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Transcript of Senior Capstone Report
PENNSTATE
Fork and Spoon Holder
Final Report
May 4, 2015
Jennifer Kohler
Brian Leap
JD Maguire
Grace Warkulwiz
Evan Witmer
No - Intellectual Property Rights Agreement
No - Non-Disclosure Agreement
2
Executive Summary The objective of this project was to design a device that would allow the client, who has a
muscular/neurological disability, to eat independently. The client suffers from Charcot-Marie-Tooth
(CMT) disease, which affects the peripheral nerves and leads to muscular weakening, making eating
and holding utensils difficult. The device the client used in the past was created by previous Penn
State students. It was permanently attached to the client’s wrist brace and was used during three
meals a day, offering a more dynamic eating experience. The device accepted utensils of specific
sizes and locked them into place. The past design functioned like a ball-point pen; with each click of
the device’s bottom button on a surface, the utensil rotated 45 degrees in one direction.
Current products on the market do not meet the client’s needs as a user with CMT disease. The
devices do not accept a variety of eating utensil sizes, and they do not angle or rotate the utensil to
ease the transition from plate to mouth. Additionally, some of the products that would actually meet
the client’s primary needs are too bulky and technologically advanced; the client wishes to feel as
normal as possible while eating with his device. The past Penn State-designed product is preferred
over the competition because it permits utensils to rotate, allowing the client to feed himself.
Although it is preferred, the past design causes user dissatisfaction due to difficulties that arise when
exchanging the utensils. In addition, the client has complications with pushing the rotation button as
well as concerns with durability.
The three concerns of the client were addressed through the design of a new eating assistive
device. After talking to the client and watching him use the device, the team decided the primary
goal: improve upon the past rotational mechanism to increase the device’s durability and ease of use.
To accomplish this, a new rotation mechanism was implemented to freely rotate a utensil 360
degrees in both directions to any desired angle without using debilitating hardware. The team
implemented the new rotation mechanism through two different prototypes. The first included a
mechanism by which a key block on the terminal device fit into a key hole on a separate piece
attached to the client’s opposite wrist. Once the key block was inserted into the hole, the client could
rotate the utensil using his shoulder and upper arm strength. However, the client did not prefer this
design because the turning motion required of his shoulder was too strenuous. The second prototype
excluded the key hole piece and instead included an attachable wheel on the bottom of the key
block. When the wheel was rolled on any surface, including the client’s hand, the utensil rotated
freely. This roller device was preferred by the client and was customized to fit his needs. The team
made adjustments to the device’s dimensions to make the rolling mechanism more comfortable and
convenient. The final design shortened the device’s overall length and moved the wheel up closer to
the end of the client’s wrist brace.
To successfully develop a working prototype, the team was given a budget of $1000.00 that was
allocated strategically to successfully accommodate the client’s needs. The prototypes were 3D
printed in ABS plastic at the Learning Factory. The team finished the project with about a tenth of
their budget remaining. The total cost to manufacture one roller device, based on the final design,
was ~ $40.00. The team actively engaged with the client and sponsor to plan deadlines and set goals
for prototypes. The initial prototype of the terminal device was brought to the client and sponsor for
testing and feedback by the March 1, 2015, deadline. Since early March, the team has made three
additional trips back to the client and sponsor with modified versions of the two prototypes as they
either failed or progressed. The final design will be delivered to our sponsor and client on May 4,
2015, for permanent attachment to the client’s wrist brace for immediate use.
3
Table of Contents 1.0 Introduction ................................................................................................................................... 5
1.1 Initial Problem Statement ......................................................................................................... 5
1.2 Objectives ................................................................................................................................... 5
2.0 Customer Needs Assessment ........................................................................................................ 6
2.1 Gathering Customer Input ....................................................................................................... 6
2.2 Weighting of Customer Needs .................................................................................................. 6
3.0 External Search ............................................................................................................................. 8
3.1 Patents......................................................................................................................................... 8
3.2 Existing Products ....................................................................................................................... 9
4.0 Engineering Specifications ......................................................................................................... 10
4.1 Establishing Target Specifications ......................................................................................... 10
4.2 Relating Specifications to Customer Needs ........................................................................... 12
5.0 Concept Generation and Selection ............................................................................................ 12
5.1 Problem Clarification .............................................................................................................. 12
5.2 Concept Generation ................................................................................................................. 14
5.3 Concept Selection ..................................................................................................................... 17
6.0 System Level Design ................................................................................................................... 18
7.0 Special Topics .............................................................................................................................. 21
7.1 Preliminary Economic Analyses - Budget and Vendor Purchase Information ................. 21
7.2 Project Management ............................................................................................................... 21
7.3 Risk Plan and Safety................................................................................................................ 21
7.4 Ethics Statement ...................................................................................................................... 23
7.5 Environmental Statement ....................................................................................................... 23
7.6 Regulatory Considerations ..................................................................................................... 23
7.7 Communication and Coordination with Sponsor ................................................................. 23
8.0 Detailed Design ............................................................................................................................ 24
8.1 Manufacturing Process Plan................................................................................................... 25
8.2 Analysis ..................................................................................................................................... 34
8.3 Material and Material Selection Process ............................................................................... 35
8.4 Component and Component Selection Process..................................................................... 36
8.4.1 Component and Component Selection Process for Key Hole and Key Block Device ...... 36
8.4.2 Component and Component Selection Process for Rolling Device .................................. 36
4
8.5 CAD Drawings ......................................................................................................................... 37
8.6 Test Procedure ......................................................................................................................... 38
8.7 Economic Analyses - Budget and Vendor Purchase Information ....................................... 38
9.0 Final Discussion ........................................................................................................................... 39
9.1 Construction Process ............................................................................................................... 40
9.2 Test Results and Discussion .................................................................................................... 44
10.0 Conclusions and Recommendations ........................................................................................ 47
11.0 Self-Assessment (Design Criteria Satisfaction) ...................................................................... 48
11.1 Customer Needs Assessment................................................................................................. 48
11.2 Global and Societal Needs Assessment ................................................................................ 48
References .......................................................................................................................................... 49
Appendices ......................................................................................................................................... 50
Appendix A: Patent Descriptions ................................................................................................. 50
Appendix B: Detailed Existing Product Summary ..................................................................... 51
Appendix C: Budget Table ........................................................................................................... 54
Appendix D: Bill of Materials....................................................................................................... 54
Appendix E: Gantt Chart ............................................................................................................. 55
Appendix F: Resumes .................................................................................................................... 56
Appendix G: Deliverables Agreement ......................................................................................... 61
Appendix H: Design Changes since the SOW Report ................................................................ 62
Engineering Specifications ......................................................................................................... 62
Concept Generation and Selection .............................................................................................. 62
System Level Design .................................................................................................................. 65
Appendix I: Design Changes since the DSR ................................................................................ 67
Engineering Specifications ......................................................................................................... 67
Concept Generation and Selection .............................................................................................. 67
System Level Design .................................................................................................................. 68
Appendix J: Past CAD Drawings ................................................................................................. 70
Appendix K: Final CAD Drawings .............................................................................................. 74
5
1.0 Introduction Charcot-Marie-Tooth disease (CMT) is a genetically inherited disorder that affects the peripheral
nerves and is one of the most common neurological disorders in the United States, affecting
approximately one in every 2,500 people. People affected by CMT have mutations in the genes that
produce proteins involved in myelin sheaths and peripheral nerve function. The nerves affected by
these mutations are unable to communicate electrical signals and slowly degenerate as the patient
ages. Because both the motor and sensory nerves are affected, the patient may have difficulty
walking. As the disease progresses, the hand and wrist muscles weaken causing the patient to have
difficulty carrying out fine motor skills [1].
There is currently no cure for CMT, so doctors focus their efforts on rehabilitation and therapy,
which help the patients with managing physical challenges. Occupational therapists work with CMT
patients to help them maintain fine finger movements, while physical therapists develop
strengthening exercises to help maintain mobility [2]. Braces and orthopedic devices can be used to
prevent injury and to help manage the disability, but no device currently exists for CMT patients that
allows them to eat happily and normally on their own. The current products on the market lack the
ability to hold a variety of silverware sizes, while also rotating the silverware to various angles to
make feeding oneself easiest. A device needs to be created that can hold and stabilize a utensil so
that these patients can regain some independence and confidence.
1.1 Initial Problem Statement While therapy helps patients with CMT to maintain some mobility, very little has been done to
help patients maintain independence with everyday tasks, such as eating. The goal of this project is
to design a device that will allow a person lacking finger strength to eat independently. The team
will be provided past prototypes and designs and will be given the freedom to completely redesign a
device or modify a past design. The device must be able to hold a fork or spoon securely while the
patient eats, and the utensils must be removable and switched easily. The client desires to eat in
restaurants using the provided utensils; therefore, the device must be able to accommodate a broad
range of shapes and sizes. The utensil also needs to be able to rotate within the device, to mimic the
natural rotation of the hand while eating.
The sponsor for this project is the Central Pennsylvania Spinal Cord Injury (SCI) Support Group,
which consists of a team of doctors and therapists from the Penn State Milton S. Hershey Medical
Center. The Central Pennsylvania SCI Support Group helps individuals cope emotionally and
physically with their disease diagnosis, specializing on those affected by spinal cord injuries [3].
1.2 Objectives Through discussions with the client and the sponsor, many problems with the past PSU device
were conveyed. However, due to time and budget restrictions, some of these issues will not be
addressed in the proposed design, and only the primary issues will be addressed as stated above. The
team’s design will be different than past PSU prototypes in terms of internal hardware but will not
be significantly different in size, shape, or overall function. The device currently utilized by the
client is wearing out due to frequent use and mechanical imperfections. The mechanical wear is
mainly due to the rotating mechanism that is implemented in the device. The client also becomes
easily frustrated with the fact that he needs to rotate the utensil to a neutral position to remove it. The
new design will utilize a different rotation mechanism to increase the durability and to alleviate this
frustration. In addition, the client expressed that a device that could fit a more versatile range of
6
utensil widths would be beneficial. The team will decrease the column thickness in order to increase
the possible utensil width, keeping in mind that this might limit the structural integrity.
While examining the past PSU designs after meeting with the client, the team decided that the
utensil could fit more securely into the fork/spoon holder. To better meet this need, slight
modifications will be made to the internal pin. In addition to a more efficient rotation mechanism, a
more natural eating experience could result if the device were able to angle up and down vertically.
However, this would require some form of lever and clamp system and is therefore out of the scope
of the team’s work.
2.0 Customer Needs Assessment
2.1 Gathering Customer Input The needs of our client were acquired in a few different ways. Initially, the team discussed the
needs of the proposed device over a video call with our client, Marty. We also met with Dr. Hills and
Marty in person to discuss previous design prototypes and deliverables. To further develop the list of
customer needs, the client was observed using previous designs, while the team took note of
particular aspects that could be improved with the previous device. Through question and answer
sessions with the sponsor and client, the team was able to determine all of the needs that must be met
for this project. The client expressed a handful of requests, some being outside the scope of the
project. After some discussion, the primary focus of the device is to be functional and durable.
2.2 Weighting of Customer Needs Analytical Hierarchy Process (AHP) is a method used for multiple criteria decision-making.
Using an AHP matrix has numerous benefits. For one, an AHP derives priorities among criteria and
alternatives while keeping the judgment consistent. By using pair-wise comparisons, the team can
decompose the decision-making problem into a hierarchy. Once a hierarchy is established, the pair-
wise comparisons between each criterion can be made. By developing a scale of importance, values
can be assigned to a given relationship. For this AHP comparison, the team will use the following
scale:
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Table 1: AHP weighting scale
Scale Degree of Preference
1 Equal importance
3 Moderate importance of one factor over another
5 Strong or essential importance
7 Very strong importance
9 Extreme importance
Table 1 shows the possible ratings of comparisons between two factors. The scale includes
integers from 1 (equal value) to 9 (extreme difference) where the higher number represents that the
chosen factor is considered more important in greater degree than the other factor being compared.
The upper triangular matrix uses the following rules:
1. If the judgment value is on the left side of 1, actual judgment value is used.
2. If the judgment value is on the right side of 1, the reciprocal value is used.
First, a hierarchy of needs was developed to get a general idea of what categories were most
important in our design. Next, pair-wise comparisons were made according to the scale above to
“weight” each criterion. To compute the entire AHP matrix, different degrees of preference were
given to each pair-wise comparison. We came up with eight different categories that applied to our
project.
The matrix below shows that “Ease of use” was our top priority in the design of the device. This
characteristic was equally important to the next two important categories: “Functional” and
“Durable”. The client stressed the importance of these three categories due to his condition. We
decided “Ease of use” was nine times more important than “Adaptable” and “Cost” because the
device will be used exclusively by one person, daily. Hence, “Cost” was our lowest rated criteria, as
we thought the price was irrelevant for a device that will be used habitually. The “Function” and
“Durable” criterion were weighted equally, and were much more important than being reproducible.
We determined that if we made the device more durable, the reproducibility of the product is
unnecessary. The “Safety” of the device received a median weight, as we established it to be of some
importance, but not a priority.
8
Table 2: AHP Pairwise Comparison Chart to Determine Weighting for
Main Objective Categories
3.0 External Search
3.1 Patents Patents pertaining to the past Penn State fork and spoon holder are summarized in Table 2. Patent
US 3288115 A describes a ballpoint pen mechanism and the concept of protracting and retracting the
ink cartridge within it. US 5630276 A describes a self-leveling eating utensil made for people with
disabilities so that they can feed themselves. US 659341 A is a patent that focuses on a utensil’s
ability to self-stabilize using a clamp. Patent US 4389777 A pertains to a device that secures an
eating utensil to an instrument base. Additionally, patents that are relevant to the team’s new device
are charted in Table 3. A key and chuck mechanism is described in patent US 2012147 A. Each
patent focuses on a function and is categorized as affecting the mechanical, aesthetic, or technical
design for the two different devices. Additional information on all of the patents can be found in
Appendix A.
Table 3: Art-Function Matrix of Patents for Past Fork and Spoon Device
Function Mechanical Design Aesthetic Design Technical Design
Pen mechanism:
US 3288115 A
X X
Internal rotating
hardware:
US 5630276 A
X
X
Utensil clamp:
US 659341 A
X
Attachment:
US 4389777 A
X
Functional Durable Adaptable Cost Weight Reproducible Safe Ease of use Total Weight
Functional 1.00 1.00 5.00 7.00 3.00 7.00 1.00 1.00 26.00 0.19
Durable 1.00 1.00 5.00 7.00 3.00 7.00 1.00 1.00 26.00 0.19
Adaptable 0.20 0.20 1.00 3.00 0.33 1.00 0.33 0.11 6.18 0.05
Cost 0.14 0.14 0.33 1.00 0.14 0.33 0.20 0.11 2.41 0.02
Weight 0.33 0.33 3.00 7.00 1.00 3.00 1.00 0.33 16.00 0.12
Reproducabile 0.14 0.14 1.00 3.00 0.33 1.00 0.33 0.11 6.06 0.05
Safe 1.00 1.00 3.00 5.00 1.00 3.00 1.00 0.33 15.33 0.11
Ease of use 1.00 1.00 9.00 9.00 3.00 9.00 3.00 1.00 36.00 0.27
9
Table 4: Art-Function Matrix of Patents for New Fork and Spoon Device
Function Mechanical Design Aesthetic Design Technical Design
Internal rotating
hardware:
US 5630276 A
X
X
Utensil clamp:
US 659341 A
X
Key hole and key
block mechanism:
US 2012147 A
X
X
3.2 Existing Products There are a number of assistive eating devices currently available, each with its own specific
design to make eating easier for the individual end users. As shown in Figure 1, the products vary
from device cuffs that attach to the hand or arm and accept silverware (A) to adaptive utensils with
larger, softer grips that are sometimes angled or curved (B). Robotic devices also exist (C). These
three groups of products are designed in mind for a specific customer. For example, cuffs that wrap
around the palm or wrist are designed for individuals with some arm strength but little to no gripping
ability in their hands or fingers. Adaptive utensils are designed for individuals with conditions like
moderate arthritis. Robotic devices exist for individuals with limited muscle strength in their arms,
hands, and fingers. On average, attachment cuffs can cost anywhere from $5 to $30 [4-8]. Adaptive
utensils are in the $10 range [9], and robotic assistive devices are a much more expensive option,
costing hundreds to thousands of dollars [10]. An extensive summary of all research products can be
found in Appendix B.
Figure 1: A summary of the varied assistive eating devices currently on the market. Slip-on
utensil cuffs (A) and adaptive utensils (B) are some of the most common. High-tech solutions
such as robotic devices (C) are also available [5,9,10].
Although a wide range of assistive eating devices exists on the market today, similarities can be
drawn amongst the various designs. One of the most common features is an opening into which the
utensil can be inserted and held into place. This concept is seen in all of the attachment cuff products
10
and even in some adaptive silverware devices. This opening is usually a flap made out of leather,
nylon, or other materials. Most of the attachment cuff devices have utensil openings that fix the fork
or spoon parallel to the palm [4-7]. The robotic devices require purchasing customized silverware to
use with the product [10]. Specific silverware is also sometimes needed with the attachment cuffs or
adaptive utensil devices [6, 9, 10]. All of the adaptive silverware, as well as some of the attachment
cuffs, are designed to be robust and round in order to help patients maintain a firm grip during meals
[4, 7, 9].
Assistive eating devices include a broad range of products for individuals of varying disabilities.
However, there are several disadvantages specific to the Fork & Spoon semester project with the
current designs. As a result of these disadvantages, the devices do not meet the needs of individuals
with CMT disease who wish to continue to be independent eaters both at and away from home. The
first disadvantage is a lack of universal acceptance for utensil types. The existing products on the
market are not universal and usually fit only a specific type of fork or spoon. In fact, grip solutions’
“Hand Grip” is the only product that includes several differently sized slits [7]. Because of this
problem, the client with CMT disease is limited to the type of silverware he can use with these
devices, making it difficult when he goes out for meals at restaurants or friends’ houses. The second
major flaw with the current devices on the market is that most of the utensils are held in a fixed
position without the ability to rotate to additional positions once inserted. An individual utilizes
multiple rotations and anglings of the wrist while eating, and these devices do not allow for that. The
cuff products fix utensils parallel to the palm. The product “Right Angle Eating Utensil Holder” is
one of the only stationary devices that allow users to eat at an angle normal to the palm, rather than
parallel [8]. Robotic products, such as “iArm,” are large and robust [10]. Additionally, these devices
cause quite a scene for individuals. These individuals, as well as the team’s client, want to gain a
better sense of independence while staying inconspicuous.
4.0 Engineering Specifications
4.1 Establishing Target Specifications
The team redesigned the original model of the device to satisfy the new needs of the client. The
client expressed three major needs: an increase in durability, an improved rotating mechanism, and a
wider insert to fit a variety of forks and spoon sizes.
Table 4 below displays the target dimensions of the device components. The dimensions of the
key hole and key block are the most important because they need to be big enough for the client to
make the connection between the key hole and key block. These changes correspond to improving
the rotating mechanism. Another important factor is the width of the pin. The width of the pin, which
holds the utensils inside the device, must be big enough to accommodate different sizes of forks and
spoons.
11
Table 5: Initial Target Specifications and Values
Metric Importance Target Value Units
Cylinder Length 3 5.5 cm
Cylinder Outer Diameter 1 2.8 cm
Cylinder Inner Diameter 1 2.6 cm
Top Cap Length 1 1.8 cm
Top Cap Outer Diameter 1 3.5 cm
Top Cap Inner Diameter 1 3.2 cm
Bottom Cap Length 1 1.8 cm
Bottom Cap Outer Diameter 1 3.5 cm
Bottom Cap Inner Diameter 1 3.5 cm
Key Block Length 5 1.5 cm
Key Block Width 5 1.5 cm
Key Block Thickness 9 2 cm
Key Hole Length 5 3 cm
Key Hole Width 5 3 cm
Key Hole Thickness 9 3 cm
Pin Length 3 8 cm
Pin Width 7 3 cm
Area of Fabric 5 50 cm2
Spring Length 1 2.5 cm
Spring Diameter 1 2.5 cm
12
4.2 Relating Specifications to Customer Needs The team developed the Needs Metric Matrix found in Table 5. The Needs Metric Matrix
displays the client’s needs and the specification metrics that are affected by these needs. The matrix
is a tool that helped the team determine how each part of the device will be tested based off of the
specific need that it corresponds to.
Table 6: Needs Metrics Matrix
Met
ric
Cy
lin
der
Len
gth
Cy
lin
der
Ou
ter
Dia
met
er
Cy
lin
der
In
ner
Dia
met
er
To
p C
ap L
eng
th
To
p C
ap O
ute
r D
iam
eter
To
p C
ap I
nn
er D
iam
eter
Bo
tto
m C
ap L
eng
th
Bo
tto
m C
ap O
ute
r D
iam
eter
Bo
tto
m C
ap I
nn
er D
iam
eter
Key
Blo
ck L
eng
th
Key
Blo
ck W
idth
Key
Blo
ck T
hic
kn
ess
Key
Ho
le L
eng
th
Key
Ho
le W
idth
Key
Ho
le T
hic
kn
ess
Pin
Len
gth
Pin
Wid
th
Are
a o
f F
abri
c
Sp
rin
g L
eng
th
Sp
rin
g D
iam
eter
Need
Utensil stability
while eating X X X X X X X X X X X
Utensil stability
while locked X X X X X X
Internal hard-ware
can withstand
long-term use
X X X X X X X X X X X X X X X X X
Light weight X X X X X X X X X X X
Angle of fork and
spoon can be
changed
X X X X X X X X X X
Widening insert to
accept varies of
forks and spoon
X X X X X X X X X
5.0 Concept Generation and Selection
5.1 Problem Clarification
The “black-box” model and sub-function diagram of the fork and spoon holder device are shown
in Figures 2 and 3, respectively. The “black-box” model displays the inputs entering into the fork
and spoon holder device to achieve the output of the client being able to eat independently. The fork
and spoon holder device is being modified to accommodate various fork and spoon sizes. A spandex
material is used to fasten the silverware to the pin, adding overall security. The remaining parts of
the device are made out of acrylonitrile butadiene styrene (ABS) plastic, adding overall durability.
13
Figure 2: The “black-box” model graphically depicts the five inputs of the fork and spoon
holder device, outputting the overall ability to eat independently.
The sub-function diagram displays the individual functions that occur inside the device while the
client is using it. For the client to successfully eat independently, the device must be able to change
the angles of the fork and spoon easily. To ensure that the angle of the fork and spoon can change
easily, a rotating key hole and block mechanism now exists. This mechanism is ideal because the
client has limited strength to produce a force strong enough to turn the fork or spoon independently.
All the various inputs for the fork and spoon holder are necessary to achieve the required output.
Figure 3: The sub-function diagram shows how various inputs affect the individual functions
of the device and how they work together to allow the client to eat independently with the
product.
14
5.2 Concept Generation After interviewing the sponsor and client extensively, the design team has decided to focus on
tackling three primary functions. These include increasing versatility of the device to fit a broader
range of utensils, increasing durability for a longer-lasting device, and increasing security and hold
of the utensil in the terminal device. For each function, two concepts were brainstormed as possible
solutions as shown in the morphological chart in Table 6. Each of these concepts is outlined below.
Table 7: Morphological Chart for Sub-Function Concept Generation
Function Concept A Concept B
Fit a broader range of
utensils
Increase all dimensions of the
terminal device
Decrease the thickness of the
cylinder
Increase Durability Use a different material Eliminate spring/clicking action for
rotation mechanism
Create a more secure
hold for utensils
Modify slightly the shape of the
clamp to increase contact points
Add an elastic-like fabric that can
better hold utensil onto clamp
For the function of versatility, two possible solutions were brainstormed. In order to accept a
wider utensil, the team initially suggested increasing all dimensions of the terminal device. Although
this concept would expand the opening to accept larger silverware, the client expressed that he is
satisfied with the overall shape and size of the device. Therefore, this idea was eliminated. The
second solution for increased versatility was to decrease the thickness of the cylinder slightly. This
change would increase the width of the pin to hold wider utensils, while keeping the overall shape
and size of the design the same. The team decided attempt to make this change; however, a possible
limitation is negatively affecting the structural integrity of the device. A basic figure for this concept
is shown in Figure 4.
Figure 4: Decreasing the thickness of the outer cylindrical casing will be explored to
improve the overall versatility of the device.
Through the investigation of old internal hardware of a recent device that failed, the team
concluded that the materials were subject to wear due to high usage of the device by the client daily.
The metal spring wore down the plastic casing and gears. In order to alleviate some of these
degradations, the team suggested using a tougher material for the device. A tougher material will
help the product last longer with time; however, hard plastics used in 3D printing are costly and
would greatly affect the team’s budget. Another concept to address the function of durability was to
include reducing the stress that the spring exerts on the terminal device. The team proposed changing
the rotation mechanism in order to (1) make it easier for the client to change the utensil angle and (2)
increase durability. The proposed rotation mechanism is a key hole and key block set, where the
client would place the device end into a hole and rotate his shoulder/arm to rotate the utensil. The
15
key hole would need to be attached to a firm surface - either the table, client’s other hand, or the
client’s thigh. This new mechanism would decrease the action of the spring and also address the
issue of having to click the button 180 degrees if the desired angle was passed. However, the client
may not prefer using his shoulder strength to rotate the device and could have difficulty inserting the
key block into the key hole. As a result, the team will test every single prototype with the client as
soon as they are 3D printed to obtain all feedback.
Figure 5: Increased durability will be addressed in the new design by altering the rotation
mechanism of the device using a key hole and key block concept.
Modifications could also be made to the current device to improve the security of the utensil and
decrease any wiggling while eating. The past device has a pin whose shape is displayed in Figure 6.
With that design, there is only one primary contact point when the utensil is locked into place. By
altering the shape of the pin, as shown in Figure 7, the team would increase the number of contact
points and therefore increase the stability of the utensil overall. The flaw with altering the pin in this
way is that the plastic material provides no stretch or give when utensils of larger sizes are inserted
into the opening. Therefore, the team might need to investigate using a more rubber based material,
which can be 3D printed.
16
Figure 6: The current shape of the pin exhibits one primary contact point with the utensil,
decreasing silverware security during use.
Figure 7: The proposed new shape of the pin will increase contact points with the utensil,
offering better overall silverware security during meal time.
An additional concept for increasing utensil stability is adding an elastic/spandex material to a
one sided pin to better hold the fork/spoon onto a clamp. This concept is depicted in Figure 8. The
material would need to conform to varying shapes and sizes and be tight enough to prevent wiggling
while eating. The fabric would line the top of the pin with an additional piece tightly fastened on top.
The two fabric surfaces would provide friction when the utensil is inserted. A spandex material
could be used for this application because it can be fastened tightly but also has the ability to stretch
to accommodate various sizes. However, the team will be challenged by this concept when attaching
the material so that it exhibits a specific tightness that accepts and holds firmly in place very thin and
flat utensils as well as large and round ones.
17
Figure 8: A spandex fabric sleeve on top of the pin has the potential to add utensil stability
due to friction, stretch, and tightness.
5.3 Concept Selection Through discussions and brainstorming sessions, the least favored ideas from Section 5.2 were
eliminated, and the remaining concepts were added to the Pugh Scoring Matrix (Table 7). Concept A
for the function of versatility is not favored because the client expressed that the current size of the
device is satisfactory. Concept B will be attempted in the final design but may limit the structural
integrity of the device; therefore, it is not a primary concern.
The concept of a new rotation mechanism (key hole and key block) had a higher rating than the
current reference. The shape of the pin that had the highest rating was the angled pin, with the fabric
sleeve pin coming in a close second. The angled pin will increase the number of contact points with
the utensil, increasing the stability of the fork/spoon. While the fabric sleeve will also increase the
security of the utensil, it will increase the cost of the device.
18
Table 8: Pugh Scoring Matrix
Concepts
Overall Design Shape of Pin
Key Hole and
Block
Spring and Gear
(Reference Device)
Angled Pin to
Increase
Contact
Fabric Sleeve
Current Shape of
Pin
(Reference)
Selection
Criteria Weight Rating
Wgtd.
Score Rating
Wgtd.
Score Rating
Wgtd.
Score Rating
Wgtd.
Score Rating
Wgtd.
Score
Functional 0.194 4 0.776 3 0.582 5 0.970 4 0.776 3 0.582
Durable 0.194 5 0.970 3 0.582 3 0.582 3 0.582 3 0.582
Adaptable 0.046 3 0.138 3 0.138 3 0.138 3 0.138 3 0.138
Cost 0.018 3 0.054 3 0.054 3 0.054 2 0.036 3 0.054
Weight 0.119 2 0.239 3 0.358 3 0.358 4 0.477 3 0.358
Reproducible 0.045 3 0.135 3 0.135 3 0.135 3 0.135 3 0.135
Safe 0.114 3 0.343 3 0.343 3 0.343 3 0.343 3 0.343
Ease of use 0.269 5 1.343 3 0.806 3 0.806 3 0.806 3 0.806
Total
Score 3.999 2.999 3.387 3.294 2.999
Rank 1 2 1 2 3
Continu
e Yes No
Yes, primary
design Yes, alt. design No
Relative Performance Rating
Much worse than
reference 1
Worse than reference 2
Same as reference 3
Better than reference 4
Much better than reference 5
6.0 System Level Design The overall design will require the use of a “key hole and block” system to rotate the piece
holding the silverware. The key block, which is attached to the bottom gear (A), protrudes through
the bottom opening of the outer shell (B). When the utensil needs to be rotated, the block is placed
into the key hole (C) and pivoted, engaging the gears and rotating the pin (D) that holds the utensil.
The key hole can be attached to the opposite hand or leg for stabilization by use of Velcro straps or
elastic bands. The spring (E) is compressed over the utensil holder pin when the cap (F) is tightened
onto the outer shell.
19
Figure 10: Assembled View of
“Keyhole and Block Device”
Within the concept above, there are two inserts that can be used to hold the utensil. The first
insert, shown as (D) in Figures 9 and 10, resembles that of a clothespin. The utensil slides between
the two jaws, and when the spring collapses, the jaws clamp onto the utensil. The jaws are tapered
outward, so that when the jaws tighten, they apply even pressure linearly along the utensil handle. A
close-up of this design shows the tapered jaws in Figure 11 below.
The second insert, shown below in Figure 12, uses fabric to enclose the utensil inside the device.
The fabric, which is elastic in nature, can adapt to a wide variety of silverware sizes and provides
360 degrees of pressure to keep the utensil steady within the device. The fabric insert and clothespin-
style insert can be interchangeable within the device and will not require any special tools or skills to
swap out. Figure 13 shows the specification drawings, and the assembly of the proposed device.
Figure 9: Exploded View of “Keyhole and
Block Device”
20
Figure 13: Specification Drawing of Clothespin Insert Assembly in Inches
Figure 11: Clothespin Style Insert Figure 12: Fabric Style Insert
21
7.0 Special Topics
7.1 Preliminary Economic Analyses - Budget and Vendor Purchase Information A budget has been developed to properly distribute the funds needed to successfully complete the
fork and spoon holder design. The initial budget, found in Appendix C, is split into four categories:
bill of materials, equipment cost, travel, and contingency. A portion of our budget (20%) will be
allotted for any contingencies that may occur. As for travel, the use of a team member’s personal car
will minimize the team’s expenses as well as being reimbursed for gas receipts instead of mileage.
The majority of the team’s expenses will come from 3D printing different prototypes for the client.
Following the initial budget is the team’s estimated bill of materials, found in Appendix D. The bill
of materials contains the estimated prices of each material used to design the fork and spoon holder.
7.2 Project Management The project Gantt chart can be seen in Appendix E. The chart is broken down into four main
categories, the “Final Report”, the “Working Prototype”, the “Weekly Progress Reports” and
“Other”. Under the “Final Report” category, there are subsections including the “Statement of Work
(SOW) and the “Design Specification Report (DSR)”. This Gantt chart was created to keep the team
on track with major deadline and to make it easy to track progress along the way.
With the team’s technical and management skills, the customer needs will be fulfilled by the end
of the semester. A resume of each team member can be found in Appendix F. The deadlines set forth
in the Deliverables Agreement can be found in Appendix G. The major work that needs to be
completed by the end of the semester includes three major reports: (the SOW, the DSR, and the final
report. In addition, the team must present the details of the SOW to the class, assemble and test an
initial prototype, construct a final working prototype, give a final presentation, and attend the
College of Engineering design showcase.
7.3 Risk Plan and Safety The device the team is designing does not cause any safety concerns for the user. Because the
device will contact both solid and liquid food at varying temperatures, the device will be made of a
plastic that will not be altered by the temperature of the food. The team’s primary focus is to design
a device that has minimal risks.
The team identified seven risks that were ranked high, moderate, or low as displayed in Table 9.
The highest risks that the team identified were scheduling delays and the product not functioning
properly for the client. Scheduling delays are high risk because on any given day, something can
occur that can cause the team to deviate from schedule and risk missing a deadline. The way the
team will handle that is by strictly following the Gantt chart and constantly staying in
communication with one another. In addition, the device not functioning properly for the client is a
high risk because it is difficult to mimic the client’s disability while testing the prototype among the
team. The way the team is handling this is by ensuring that the client tests the device as often as
possible as the team makes the appropriate modifications to the device.
The team identified not meeting client’s needs, a change in the client’s needs, a delay in
manufacturing and assembling the device, and the device having minimal longevity as moderate
22
risk. These are moderate minimal risks because the team has several strategies set in place to
minimize these risks.
As for low risk, the team only identified the device not being reproducible for this level. The
reason for this risk being low is the device is made a minimal parts and thorough documentation of
the design will ensure easy reproduction. At the end of the semester, the team must make sure the
design is saved and given to the sponsor as well as every team member future reference.
Table 9. Risk Management Plan
Risk Level Actions to Minimize Fall Back Strategy
Not meeting client’s
needs Moderate Testing prototypes
early and often
Listening to the
client’s exact needs
Focus on one main need
rather than multiple needs at a
time
Ensuring that team can print
old device in case new device
does not meet needs
Change in client’s
needs Moderate Constantly be in
contact with sponsor
and client
Making a device that
is adaptable to the
client’s needs
Make small modifications to
device to meet needs
Adjust budget for
modification and rush
assembly
Scheduling delays High Utilize Gantt chart
Working ahead of
scheduled due dates
Keep in constant contact with
team members
Include extra time before
deadlines
Delay in
manufacturing and
assembling
Moderate Provide 3D sketches
for printing two days
in advance to
Learning Factory
Make sure all parts
are correctly
measured and fit
properly
Use secondary 3D printer in
Hammond Building
Use past parts to successfully
assemble a working device
Device does not
function properly
for client
High Allowing client to
test prototypes in
advance to ensure
functionality
Keeping in mind
client’s disability as
prototypes are being
assembled
Make small modifications to
past design so client at least
has a working device
Rush to clients house to make
small repairs to device so that
it functions properly
Device has minimal
longevity Moderate Assuring that the
device is made from
Producing multiple
prototypes so if one breaks,
23
a durable material
Testing material to
ensure that it can
withstand forces
client puts on it
client will have extras
Have a back-up material if
current material used is not
durable enough
Device is not
reproducible Low Proper
documentation and
saving of all files for
future use
Having 3D prints
readily available
Ensure sponsor’s personal 3D
printer has all files relating to
device’s design
Give design files to Dr. Hills
to have future groups
reproduce device
7.4 Ethics Statement The team will conduct our research in a manner that is consistent with accepted scientific
methods, maintaining the highest standards of honesty and integrity in all professional endeavors.
All sources of inspiration, information, and assistance with the project design will be recognized and
stated. The safety of the design for the user will be guaranteed and will always be the top priority of
the team. All progress, ideas, and concerns regarding the design will be shared immediately between
team members, the user, and the team’s sponsor. Current patents will not be infringed upon. The
team’s intentions and concerns will never veer from improving the life and daily habits of the
disabled user.
7.5 Environmental Statement The team does not expect major environmental concerns in the manufacture of the design or its
materials. The team will abide by environmental regulations and standards in the creation of its
design. Environmental impact will be strongly considered with each of the team’s decisions. The
processes selected for the manufacture of the design will produce the minimum environmental
impact achievable. There will be an emphasis on using recycled and biodegradable materials
whenever the option is available.
7.6 Regulatory Considerations FDA review will not be necessary as the device is categorized as a low-risk medical device since
it is not inserted into the user’s body. Low-risk medical devices do not require premarket review
when they are for the same use as an already legally-marketed device. Splints and gloves for helping
users with difficulty using their fingers already legally exist on the market place. Of the four major
forms of certification (UL, CSA, ETL or CE), the only certification that would apply to the design
would be UL. Due to the low safety risk of the design, a UL certification does not seem necessary.
The device will most likely be assumed safe by any user familiar with splints and other assistive
living devices.
7.7 Communication and Coordination with Sponsor The team communicates with the primary contact, Dr. Hills, and the client via different methods
dependent on the purpose of the interaction. Email is used in order to quickly send the sponsor
documentation such as progress reports, design ideas, and other important documentation involved
in the creation of the team’s design. Email is also used in order to set up the site visits to the sponsor.
The site visits occur whenever new prototypes need to be tested by the user or when supplies and
24
models from past designs need to be collected and analyzed. When the team wants to have an
interactive discussion with the client, a Skype session is set up.
8.0 Detailed Design
Section 8.0.1 Modifications to Statement of Work Sections
8.0.1.1. Introduction – no change
8.0.1.2. Customer Needs – no change
8.0.1.3. External Search An additional patent has been found that is relevant to the roller wheel of the rolling device’s
design. Information on this patent can be found in Appendix A.
8.0.1.4. Engineering Specifications
At the request of the client, several changes have been made to the engineering specifications of
the initial prototype designs. The importance of the cylinder length was changed from a 3 to a 6 due
to new concerns from Marty. The client’s thumb was dragging through his food on a daily basis, and
as a result, the team revised the length of the cylinder to attempt to fix this issue. The original
cylinder’s length value of 5.5 cm was changed to 9.2 cm. In order to accommodate for the added 2
cm to the cylinder length value, 2 cm was added to the original key block length as well. The target
value of 1.5 cm was changed to 3.5 cm. The original key hole width target value was changed from 3
cm to 1.5 cm to match the key block width target value of 1.5 cm.
Several metrics and values have been removed from the target specifications because some
aspects of the original prototype are longer relevant or present in the team’s new prototypes. The
spring length and spring diameter target values were removed because the team decided to not
incorporate a spring into the design. The area of fabric target value was removed because the team is
no longer pursuing the fabric pin insert. Revisions to the target specifications can be seen in Table
H.1 in Appendix H.
8.0.1.5. Concept Generation and Selection
The primary design concept has been modified to include an additional prototype design with a
rolling rotation mechanism. In addition, the key hole piece of the key block and hole prototype has
been redesigned to more comfortably fit the client’s wrist during use. Details of these modifications
are described in Appendix H along with Figures H.1-H.3.
8.0.1.6. System Level Design
A revised exploded view of the system is shown in Appendix H in Figures H.4-H.6. The changes
include a modified pin insert, an extended outer shell, a different key hole attachment, and an
additional roller prototype.
8.0.1.7. Special Topics The Gantt Chart has been updated to reflect current timeline of deliverables as seen in Appendix
E. The Bill of Materials in Appendix D has been updated to include material purchased since the
SOW Report. These materials include fabric, Velcro, suction cups, Dycem, and 3D printed
prototypes.
25
8.1 Manufacturing Process Plan If the device was to be manufactured by a non-Fork & Spoon team member, the team will provide
the party with the proper STL files. The necessary files were finalized by the team in SolidWorks
and converted to STL files in March 2015. The team will share the files via email with those
manufacturing the device. The manufacturing process currently takes place at the Penn State
Learning Factory. All one needs to do is provide the Learning Factory employees with the Fork &
Spoon STL files obtained from the team. The employees take care of uploading the files to the
printer, programming the printer with various settings, and removing support material. As a result,
the team cannot contribute any details regarding the printing process since they rely on an outside
source for printing.
The following materials are needed to successfully manufacture the key hole and key block
device: a total of five STL files (one for each piece of the device), Dimension 1200es 3D printer,
ABS plastic (to be printed), ½” thick blue open-cell T-stick foam*, superglue, and 1” wide non-
industrial Velcro. The following steps are summarized in Table 10:
1. Upload the five STL files at the Penn State Learning factory to the Dimension 1200es 3D
printer with the help of an employee.
2. Print all five pieces on the Dimension 1200es 3D printer using ABS plastic (~ nine hours
total). The pieces include the outer casing, key block piece, pin, cap, and radial key hole
piece.
3. Prepare the foam piece: cut a piece of ½” thick blue open-cell T-foam 2 inches (48 mm) long
and 0.8 inches (21 mm) wide. Leave the adhesive backing on the foam. Seal the front edge of
the foam completely with a layer of superglue. Let it dry until it hardens. See reference image
below.
4. Prepare the pin piece: cut a piece of ½” thick blue open-cell T-foam 2 inches (48 mm) long
and 0.8 inches (21 mm) wide. Secure the piece of foam with superglue to one of the pin
sides. Be sure to superglue the piece foam side down. Keep the adhesive backing on the foam
and unsecured. See reference imagine below.
26
5. Hold the outer casing with the large opening facing upwards and the small opening facing
downwards. Drop the key block piece to the bottom with the gears facing up. Pull on the
block to ensure that the piece is as far down as it can go inside of the casing. See reference
image below.
27
6. Drop the pin insert with the gears facing down into the outer casing so that it falls on top of
the key block piece. See reference image below.
7. Locate the circular knobs on the outside of the outer casing piece. Place the cap onto the top
of the outer casing, making sure that the knob enters the opening of the cap’s “L” slit. Once
the knob has made it to the back of the “L” slit opening, turn the cap piece so that the knob
slides along the horizontal length of the “L” slit. One will know when the knobs are securely
in the slits because the cap will not rotate further. Although the material is durable, take
caution with this step and be gentle so that the cap piece does not break. See reference
images below.
28
8. Cut a piece of the 1” wide Velcro 8 inches (203 mm) long. Insert it through the openings of
the radial key hole piece with the Velcro side facing upwards.
* The color of open-cell T-foam in medical applications corresponds to different resistances. This is
universal. For example, blue open-cell T-foam is more resistive than pink, yet less resistive than
black.
The following materials are needed to successfully manufacture the rolling device: a total of five
STL files (one for each piece of the device), Dimension 1200es 3D printer, ABS plastic (to be
printed), ½” thick blue open-cell T-stick foam, superglue, and Dycem. The following steps are
summarized in Table 11:
1. Upload the five STL files at the Penn State Learning factory to the Dimension 1200es 3D
printer with the help of an employee.
2. Print all five pieces on the Dimension 1200es 3D printer using ABS plastic (~ nine hours
total). The pieces include the outer casing, key block piece, pin, cap, and roller wheel.
3. Prepare the foam piece: cut a piece of ½” thick blue open-cell T-foam 2 inches (48 mm) long
and 0.8 inches (21 mm) wide. Leave the adhesive backing on the foam. Seal the front edge of
the foam completely with a layer of superglue. Let it dry until it hardens. See reference image
below.
29
4. Prepare the pin piece: cut a piece of ½” thick blue open-cell T-foam 2 inches (48 mm) long
and 0.8 inches (21 mm) wide. Secure the piece of foam with superglue to one of the pin
sides. Be sure to superglue the piece foam side down. Keep the adhesive backing on the foam
and unsecured. See reference imagine below.
5. Prepare the roller wheel: cut a piece of Dycem 1.4 inches (35 mm) long and 0.3 inches (6.5
mm) wide. Superglue it to the outer rim of the roller wheel.
6. Hold the outer casing with the large opening facing upwards and the small opening facing
downwards. Drop the key block piece to the bottom with the gears facing up. Pull on the
block to ensure that the piece is as far down as it can go inside of the casing. See reference
30
image below.
7. Drop the pin insert with the gears facing down into the outer casing so that it falls on top of
the key block piece. See reference image below.
31
8. Locate the circular knobs on the outside of the outer casing piece. Place the cap onto the top
of the outer casing, making sure that the knob enters the opening of the cap’s “L” slit. Once
the knob has made it to the back of the “L” slit opening, turn the cap piece so that the knob
slides along the horizontal length of the “L” slit. One will know when the knobs are securely
in the slits because the cap will not rotate further. Although the material is durable, take
caution with this step and be gentle so that the cap piece does not break. See reference
images below.
9. Put a layer of superglue in the circular indent on the roller piece. Snap the roller wheel onto
the key block by lining up the circular block with the circular indent on the roller piece and
pushing down.
Table 10. Manufacturing Process Plan for Key Hole and Key Block Device
ASSEMBLY NAME MATERIAL
TYPE
RAW
STOCK
SIZE
OPERATIONS
Outer casing ABS plastic N/A Load STL file and print piece on
Dimension 3D printer.
Check for the circular knobs – are there
four raised printed circles?
Key block ABS plastic N/A Load STL file and print piece on
Dimension 3D printer.
32
Check gears - are there 3D rectangles all
the way around the top of the piece? Are
any of the gears missing or not fully
printed?
Key hole ABS plastic
N/A
Load STL file and print piece on
Dimension 3D printer.
Velcro 12’ x ¾”
roll
Cut an 8 inch piece - insert through
straps with Velcro side facing up.
Pin ABS plastic
N/A
Load STL file and print piece on
Dimension 3D printer.
Check gears - are there 3D rectangles all
the way around the bottom of the piece?
Are any of the gears missing or not fully
printed?
½” thick blue
open-cell T-stick
foam
Superglue
1/2" x 6" x
72" sheet
Cut a piece of foam 2 inches long and
0.8 inches wide. Secure the pieces with
superglue to either side of the pin.
Cap ABS plastic N/A Load STL file and print piece on
Dimension 3D printer.
ASSEMBLY NAME MATERIAL
TYPE
RAW
STOCK
SIZE
OPERATIONS
Terminal device
(everything excluding
the key hole piece)
Obtain outer casing - large opening
facing upwards.
Drop the key block into casing with
gears facing up.
Drop the pin into casing with gears
facing down.
Lock cap onto casing using slits and
knobs.
33
Table 11. Manufacturing Process Plan for Rolling Device
ASSEMBLY
NAME
MATERIAL
TYPE
RAW
STOCK
SIZE
OPERATIONS
Outer casing ABS plastic N/A Load STL file and print piece on Dimension
3D printer.
Check that locking knobs on the outside of
the case were printed successfully.
Key block ABS plastic N/A Load STL file and print piece on Dimension
3D printer.
Check gears to make sure that they were
printed successfully.
Roller wheel ABC plastic
N/A
Load STL file and print piece on Dimension
3D printer.
Dycem
Superglue
16’ x 1-⅛”
strip
Cut a strip 1.4 inches long and 0.3 inches
wide. Superglue to the outer edge of the
wheel.
Pin ABS plastic N/A Load STL file and print piece on Dimension
3D printer.
Check gears to make sure that they were
printed successfully.
½” thick blue open-
cell T-stick foam
Superglue
1
1/2" x 6" x
72" sheet
Cut a piece of foam 2 inches long and 0.8
inches wide. Secure the pieces with
superglue to either side of the pin.
Cap ABS plastic N/A Load STL file and print piece on Dimension
3D printer.
ASSEMBLY
NAME
MATERIAL
TYPE
RAW
STOCK
SIZE
OPERATIONS
34
Terminal
device
Superglue Obtain outer casing - large opening facing
upwards.
Drop the key block into casing with gears
facing up.
Drop the pin into casing with gears facing
down.
Lock the cap onto casing using slits and
knobs.
Fasten the roller wheel to the bottom of the
key block piece with superglue.
8.2 Analysis The team did not find it necessary to do any Finite Element Analysis to prove our design. The
initial prototype designs were modeled after past working Penn State prototypes that the client is
currently using. Because the client has had successful experiences with the past Penn State
prototypes that were printed using ABS plastic, the material was assumed to be strong enough to
withstand any stresses or forces exerted on it during use.
Because the team was unsure as to how the new assembly and rotation mechanism would work,
the group was careful not to waste part of the budget by printing a full prototype in ABS plastic.
Therefore, experimentation of the preliminary printing of the main parts was carried out using the
MakerBot printer in the Learning Factory. The MakerBot printer was free to use; however, the
quality was very poor. The MakerBot only printed one piece before the machine broke. The team
analyzed what was printed and consulted the Learning Factory employees. During the consultation,
the employees notified the team that the MakerBot breaks down almost every time a user tries to
print on it. As a result, the team came up with a plan B.
The team decided to print some of the pieces from the initial prototype using a more reliable
printing machine: the Dimension 1200es 3D printer. Only the pin insert, the key block, and the key
hole pieces were printed to save material and money because they were the only new or modified
pieces. The group obtained past prototype pieces from the sponsor and used them in combination
with the newly printed pieces to test the assembly method and rotation mechanism. Through this
experiment, the team found that some of the pieces needed to be redimensioned slightly in order to
fit together properly and carry out the desired functionality. Initially, the team spent some time in the
Learning Factory filing the plastic and eventually redimensioned the SolidWorks drawings to
finalize the design dimensions. These new dimensions are reflected in the Engineering Specification
section.
The rotation of the two prototypes was analyzed for functionality and ease of rotation. The
rotation of the key hole and key block device resulted from friction between the gearing pieces and
the outer casing. Therefore, the force needed to rotate the utensil could not be directly measured.
Through initial testing, the team was able to rotate the utensil with minimal shoulder force.
Subsequent testing was carried out with the client. A greater force was required when using the key
hole piece that was attached to the table compared to the key hole piece attached to the client’s
opposing hand. Movement with both hands afforded by attachment to the opposing hand allowed for
easier rotation; however, the team felt that the client exerted too much energy and effort in order to
35
turn the utensil a small angle. The team simulated Marty’s motions while using the device and
determined that the utensil would rotate at most 45 degrees with each shoulder movement. The client
would then need to reposition the device to continue rotating the utensil.
During the team’s meeting with the client and during testing of the key hole and key block
prototype, a new idea for a different rotation mechanism was created. A rotation mechanism that
could be implemented by the client by simply rolling the block piece along the table edge or a pant
leg would require less effort from the client. After the prototype was designed and 3D printed, the
team analyzed its ease of rotation by measuring the distance it needed to be rolled along the table
edge in order to rotate 180 degrees which measured approximately 2.7 inches (68.6 mm). Because
the rotation of the utensil is solely dependent on the rotation of the gear piece, the relationship was
linear, and minimal rolling was necessary to rotate the utensil.
8.3 Material and Material Selection Process To successfully design a prototype tailored to the team’s client, three major needs must be
satisfied – versatility, security, and durability. Material selection for the prototype was used to
satisfy the need for durability. To ensure that the team’s prototype was durable, a relatively strong
material was essential. Because the team intended to 3D print the prototype, a specific type of
thermoplastic polymer had to be chosen. Due to the constraints of 3D printing in the Penn State
Learning Factory, the team had to choose from three different materials – acrylonitrile butadiene
styrene (ABS), polylactic acid (PLA), and high impact polystyrene (HIPS). After thoroughly
researching these materials, the team decided to print the prototypes with ABS. ABS is the strongest
and cheapest of the three, exhibiting high temperature resistance. HIPS is dissolvable in most
liquids, which is unacceptable for a device that comes in close contact with liquids during meals.
PLA stores moisture from the air, diminishing the strength of the material over time.
All three prototypes constructed to date have been printed with ABS. There are only two
components of the prototypes that include other materials adhered to them. The first is the pin that
holds the utensil in place. Because the client stressed that he liked the foam inserts in the model he
uses now, it was obvious to insert foam into the team’s newly designed pin. Marty’s occupational
therapist placed closed-cell foam in the model he uses now; therefore, the team reached out to her to
obtain similar materials for the new prototypes. The team experimented with both open-cell and
closed-cell foam in the new pin insert. After many tests, the team decided to use the open-cell foam
because it had better memory than the closed-cell foam allowing the foam to mold better around the
utensil.
The second part of the new prototype design that has material adhered to it is the wheel
attachment at the bottom of the roller prototype. Because the wheel must be in contact with another
surface and the coefficient of friction must be high in order to rotate the wheel, the team researched
non-slip materials. A material that is commonly used by physical therapists is Dycem. Dycem is
non-slip, rubber-like plastic. The team decided to purchase Dycem and adhere it to the entire wheel,
increasing the coefficient of friction when the wheel comes in contact with a surface. With much
research and trial of materials, the team has decided that the prototypes will be constructed from
three different materials: ABS, open-cell foam, and Dycem.
36
8.4 Component and Component Selection Process 8.4.1 Component and Component Selection Process for Key Hole and Key Block Device
There are five main components for the key hole and key block device. These include the outer
casing, the key block/gear piece, the key hole, the pin, and the cap. Due to the ease of
manufacturing, availability, cost, and time, all components were designed in SolidWorks and printed
on a 3D printer.
The outer casing of the device was designed to be cylindrical, with an overall length of 3.63
inches (92.20 mm) and a diameter of 0.886 inches (22.50 mm). This shape and size were based on
those of the past Penn State device, due to previous client satisfaction with the size of device. The
outer casing in combination with the cap has an indentation that allows for easy attachment of the
device to a splint worn by the client. The cap has grooves that align with knobs on the outer casing,
and when twisted, the cap is securely fastened into place. The cap holds the pin securely in the
device.
The pin shape was also kept similar to past Penn State designs, because it has proven to hold a
utensil securely in place. The pin resembles a clothespin, in which a utensil can be inserted and
removed with ease. The team has attached one open-cell foam insert to one side of the pin in order to
cushion and hold the utensil in place. The team also experimented with Dycem, a non-stick material,
to see how well it held the utensil in place. However, the group found that the hold would be too
strong for the client to manipulate, and he would not be able to remove the utensil from the Dycem.
For this particular prototype design, a key hole and key block were designed together in order to
enable rotation of the utensil. The gear piece that previously had a button on the end (used in the past
Penn State prototype) was redesigned to have a rectangular block on the end. This block was
designed with the client in mind and is fairly large and simple in shape to ensure easy insertion into
the key hole piece. The key hole piece was designed with a semi-circle shape to comfortably fit on
the side of the client’s wrist. There is a large rectangular hole for insertion of the key block. This
wrist piece has slots for Velcro to be attached and used for attachment to the client’s wrist. Velcro
was chosen for this design because the client can successfully attach and detach the Velcro on his
splint using his mouth.
8.4.2 Component and Component Selection Process for Rolling Device There are five main components for the rolling device. These include the outer casing, the pin, the
cap, the gear piece/roller cylinder, and the wheel attachment. The pin, outer casing, and cap designs
were all chosen for the same factors described in the section 8.4.1.
This prototype was designed to have a different rotation mechanism, where the client can roll a
wheel along a table edge or pant leg to rotate the utensil. The gear piece that previously had a button
on the end (used in the past Penn State prototype) was redesigned to be a simple cylinder. An
attachable wheel with a circular cut-out can be secured onto the end of the gear piece/cylinder block.
This wheel was designed to be the same diameter as the base of the outer casing. The wheel has been
made detachable so that during the prototyping process, it can be reprinted in different sizes without
having to re-print the entire gear piece. Dycem, a readily available and low-cost material, will be
added to the wheel surfaces to increase friction between the wheel and table edge.
37
There were minimal tradeoffs created by modifying the design to a roller. By changing the key
block to a cylinder with a wheel, we decreased the contact point for rotation. The ease of wheel
rotation depends slightly on the shape and thickness of the table it will be used on. However, the
client can easily rotate the wheel on his opposite hand. Moreover, there is an additional material and
cost necessary for assembly (Dycem). This new design also requires more ABS plastic to be printed
due to elongation of the device and an added wheel piece.
8.5 CAD Drawings The assembled view of the key block device can be seen in Figure 14 below. This prototype uses
the square key and key hole to rotate the inner pin that holds the utensil. Within this prototype, the
inner pin that holds the utensil has been expanded and fitted with compressive foam to better secure
the fork or spoon. The key hole at the bottom of the picture has been designed with an arc to be
strapped to the user’s wrist.
Figure 14: Assembled view of key hole and block device
The assembled view and drawing of the wheel roller device can be seen below in Figure 15. This
prototype uses the same internal pieces as the key block device. However, there is a cylinder that
extends below the casing with a rotational wheel at the end. The wheel rotates the inner pin when
rolled along a table edge or pant leg. This wheel is covered with Dycem to increase the coefficient of
friction between the wheel and the material it comes in contact with to induce rotation.
Figure 15: Assembled view of roller device
38
All individual dimensioned component drawings are shown in Appendix J in Figures J.1-J.8.
8.6 Test Procedure All prototypes and final designs will be tested for the following characteristics: ease of utensil
rotation, ease of inserting and removing utensils, and stability of the utensil while eating. All designs
will be tested by our client Marty at his home for convenience.
Ease of rotation will assess how easy it is to use the key hole and key block or roller components.
Our client will rotate a utensil in the holder to three positions he finds essential for his daily eating
habits and judge how difficult it was to accomplish. Ease of insertion/removal will assess the
versatility of utensils capable of being used in the new design. Our client will attempt to insert then
remove three different forks with varying sized handles ranging from thin to thick. He will then
judge how difficult each fork was inserted and then removed. Stability of the utensil will test how
still and secure the utensils remain within the holder during dining. Our client will cut and eat a roll
with a fork inserted into the holder. The client will judge how steady the fork felt within the holder
while dining.
The client will rate each of these three tests on a scale of 1 to 5; 1 being much worse than his
current holder, 3 being the same, and 5 being much better. An example of the evaluation form can be
seen in Table 12.
Table 12. Sample Design Evaluation Form
Design Evaluation Sheet Design Creator: Fork & Spoon Holder Capstone Project
Tested By: Marty Kester
Prototype with Key Hole and Key Block Mechanism
Name of Test Ease of
rotation test
Ease of
insertion/removal test
Stability of the
utensil test
Rating (1-5)
Comments (Suggestions,
Improvements, etc.)
8.7 Economic Analyses - Budget and Vendor Purchase Information The budget and Bill of Materials (BOM) tables have been updated in Appendix C and D. The
team spent a majority of the budget on developing different prototypes to meet the client’s needs.
Materials such as Velcro, Dycem, foam, adhesives, fabrics, and suction cups were also purchased to
test different ways to improve the team’s prototype. After travel expenses were calculated, the team
has approximately 65% of the budget remaining. The budget contains some rough estimates for how
much money the team will spend on each category.
39
9.0 Final Discussion Section 9.0.1 Modifications to Statement of Work and DSR Sections
9.0.1.1. Introduction – no change
9.0.1.2. Customer Needs – no change
9.0.1.3. External Search – no change
9.0.1.4. Engineering Specifications
Several changes were made to the engineering specifications to achieve a final prototype as a
result of client and team discussions. Some specifications were deleted from the table, including the
key block and key hole components as they are no longer relevant to the final design. Due to
Marty’s concerns with the device sticking out too far and being too close to his hand, the team
modified the outer casing. An extension length of approximately 1.0 cm was attached to the top of
the outer casing. To address the device being too long, the outer casing was shortened to 6.4 cm.
Lastly, the team decided to simplify the device’s design by combining the two original pieces for the
pin and key block into one long pin piece with a longer mouth. Doing so effectively increased the
security of the utensil because the utensil could then be inserted farther into the device. The
importance of the pin length was changed from a 3 to a 6. The length of the pin is now much longer
due to combining the pin piece and the lower gear block piece. The entire pin length is now 14.5 cm.
Lastly, a roller wheel was added as a metric in the target specifications table. The wheel has a
diameter of 3.2 cm. All revisions to target specifications can be seen in Table I.1 in Appendix I.
9.0.1.5. Concept Generation and Selection
The general concept of a roller wheel rotation mechanism did not change since the DSR.
However, the team did design a thumb rest cap attachment piece for added comfort to the client. The
client ended up not liking the thumb rest, and the design concept was disregarded in the final device.
Details regarding the thumb rest cap can be found in Appendix I.
9.0.1.6. System Level Design
A revised exploded view and assembled view of the system is shown in Appendix I in Figures
I.3-I.4. New CAD specification drawings can be found in Appendix K, Figures K.1-K.8. The final
prototype utilizes the roller wheel rotation mechanism. It has been shortened to better satisfy the
client and a dropdown component has been added to the outer shell to drop the device away from the
palm for a more comfortable thumb position. The pin piece has been combined with the key block
gear piece to simplify the design and to elongate the pin gap. This allows the client to insert the
utensils further into the device and for better security of the utensil. In addition, the wheel
attachment hole has been modified to a square shape to minimize slipping between the cylinder
block and the wheel.
9.0.1.7. Special Topics
The Gantt Chart has been updated to reflect the complete timeline of deliverables as seen in
Appendix E. Appendix C and D contain the finalized budget and Bill of Materials (BOM). The
majority of the budget (~50%) was spent on 3D printing the team’s prototypes. It was important that
the team develop the best prototype to fit the client’s changing needs. A total of fourteen prototypes
were printed to ensure that the client was satisfied with the team’s final prototype. Of the $1000
allotted to the team, all but $88.61 was used. The budget breakdown is as followed: $65 for the
showcase poster, $192.25 for traveling to and from the team’s client/sponsor at Hershey Medical,
40
$112.30 for materials used to construct the final prototype, and $541.84 for 3D printing all of the
prototypes.
9.0.1.8 Detailed Design
The key hole and key block device was not changed or modified. As a result of the feedback from
the client, the team concluded to leave this design behind and continue further with the roller device.
The manufacturing and construction process for the final roller device can be found in Section 9.1.
9.1 Construction Process
If the device was to be constructed by a non-Fork & Spoon team member, the team will provide
the party with the proper STL files. The necessary files were finalized by the team in SolidWorks
and converted to STL files in April 2015. The team will share the files via email with those
manufacturing the device. The manufacturing process currently takes place at the Penn State
Learning Factory. All one needs to do is provide the Learning Factory employees with the Fork &
Spoon STL files obtained from the team. The employees take care of uploading the files to the
printer, programming the printer with various settings, and removing support material. As a result,
the team cannot contribute any details regarding the printing process since they rely on an outside
source for printing.
The following materials are needed to successfully manufacture and construct the finalized roller
device: a total of four STL files (one for each piece of the device), Dimension 1200es 3D printer,
ABS plastic (to be printed), ½” thick blue open-cell T-stick foam*, superglue, and Dycem. The
following steps are summarized in Table 13:
1. Upload the four STL files at the Penn State Learning factory to the Dimension 1200es 3D
printer with the help of an employee.
2. Print all five pieces on the Dimension 1200es 3D printer using ABS plastic (~ nine hours
total). The pieces include the outer casing, key block piece, pin, cap, and roller wheel.
3. Prepare the foam piece: cut a piece of ½” thick blue open-cell T-foam 2 inches (48 mm) long
and 0.8 inches (21mm) wide. Leave the adhesive backing on the foam. Seal the front edge of
the foam completely with a layer of superglue. Let it dry until it hardens. See reference
images below.
41
4. Prepare the pin piece: Slide the foam piece from Step 3 into the pin mouth until is it
completely inserted (no adhesive is needed).
5. Prepare the roller wheel: cut a piece of Dycem 1.4 inches (35 mm) long and 0.3 inches (6.5
mm) wide. Superglue it to the outer rim of the roller wheel. See reference imagine below.
6. Hold the outer casing with the large opening facing upwards and the small opening facing
downwards. Drop the pin piece to the bottom with the mouth of the pin facing up. Pull on the
cylindrical extension to ensure that the piece is as far down as it can go inside of the casing.
See reference image below.
42
7. Locate the circular knobs on the outside of the outer casing piece. Place the cap onto the top
of the outer casing, making sure that the knob enters the opening of the cap’s “L” slit. Once
the knob has made it to the back of the “L” slit opening, turn the cap piece so that the knob
slides along the horizontal length of the “L” slit. One will know when the knobs are securely
in the slits because the cap will not rotate further. Although the material is durable, take
caution with this step and be gentle so that the cap piece does not break. See reference
images below.
8. Put a layer of superglue in the circular indent on the roller piece. Snap the roller wheel onto
the key block by lining up the circular block with the circular indent on the roller piece and
pushing down. See reference image below.
43
Table 13. Manufacturing/Construction Process Plan for Final Roller Device
ASSEMBLY
NAME
MATERIAL
TYPE
RAW
STOCK
SIZE
OPERATIONS
Outer casing ABS plastic N/A Load STL file and print piece on Dimension
3D printer.
Check that locking knobs on the outside of the
case were printed successfully.
Roller wheel ABC plastic
N/A
Load STL file and print piece on Dimension
3D printer.
Dycem
Superglue
16’ x 1-⅛”
strip
Cut a strip 1.4 inches long and 0.3 inches
wide. Superglue to the outer edge of the
wheel.
44
Pin ABS plastic N/A Load STL file and print piece on Dimension
3D printer.
½” thick blue open
cell T-stick foam
1
1/2" x 6" x
72" sheet
Cut a piece of foam 2 inches long and 0.8
inches wide. Slide the foam piece into the pin,
keeping the white adhesive backing attached.
Cap ABS plastic N/A Load STL file and print piece on Dimension
3D printer.
Complete roller
device
Superglue Obtain outer casing - large opening facing
upwards.
Drop the pin into casing with the mouth facing
upwards.
Lock the cap onto casing using “L” slits and
knobs.
Fasten the roller wheel to the bottom of the
key block piece with superglue.
A picture of the final assembled roller device can be seen below in Figure 16:
Figure 16: Assembled roller device
* The color of open-cell T-foam in medical applications corresponds to different resistances. This is
universal. For example, blue open-cell T-foam is more resistive than pink, yet less resistive than
black.
9.2 Test Results and Discussion The team identified five possible modes of failure to test. These modes of failure include
component stress due to rotation, breakage or slipping of Dycem, decreased friction between the
wheel and block (slipping), versatility of utensils that can be inserted/removed, and foam security on
utensil. The team designed tests to analyse each of these modes of failure, and these included three
45
durability tests, a utensil versatility test, and a foam security test. Table 14 briefly describes each of
the tests and their results.
Table 14. Failure Modes and Test Results Failure mode Test Results
1. Component stress due
to rotation
Screw gun rotation test Rotated 1,805 times without failure
2. Breakage or slipping of
Dycem
Grip strength test Did not break or slip with team
member’s greatest strength
3. Friction between block
and wheel
Rotation test Minimal slipping occurred; team
changed attachment shape from a
circle to a square
4. Versatility of utensil
width
Tested widest/thickest
and thinnest forks in the
device
Thick fork is held tightly and is
more difficult to insert; thin fork is
easy to insert with minimal sliding
5. Foam security Added weight to utensil
and held upside down in
device
Foam held up to 54.1 grams, which
is more than the heaviest spoon on
the market
The first test that was conducted was a rotation test to determine how many times the device
could be rotated prior to failure due to component stress. The team attached the device to a setup
with a screw gun drilled into a wooden peg that was attached to the wheel of the device. The outer
casing of the device was held in place with duct tape. This setup can be seen below in Figure 17.
Figure 17: Screw gun setup with device for rotation testing
The screw gun was set to a continuous speed, and the team calculated the rpm by counting the
number of rotations in 15 seconds and multiplying this value by 4. The screw gun was then left on
for a set period of time, and the number of rotations was calculated by multiplying the rpm by the
time in minutes. The utensil was rotated a total number of 1,805 times before the prototype was
damaged by the speed of the drill and could no longer rotate. After these rotations, the device was
still functional. Failure occurred when the drill was set on too high of a speed. The ABS plastic of
46
the device melted the cap shut onto the outer casing. This would not happen during client use as he
would never rotate the pin at such a high speed. The team is confident that minimal wear occurs on
the device as it is rotated, and the stress put on the device by the client is considerably less than that
of the drill.
The second test was to test the durability of the Dycem on the wheel. To ensure that the Dycem
that is glued to the end of the wheel will not rip or slip off, a strength test was conducted. A member
of the team used a device to measure his grip strength. The wheel was then taken and dragged
against a table. The wheel took a lot of force before it slipped on the pin, and the Dycem did not rip
off. This confirms that the Dycem on the end of the wheel would withstand the force that the client
would exert on the Dycem.
During a second rotation test, the friction between the wheel and the cylinder block piece was
tested. The block was held steady, and the wheel was rotated by itself. After approximately 10
minutes of rotating the wheel on high speed with the screw gun, the wheel began to slip off of the
cylinder block. In order to address this potential issue, the team modified the base of the cylinder
block and changed the shape of the hole in the wheel from a circle to a square. That way, the wheel
would not slip off of the block after an extended duration of use. A picture of the modified block
attachment hole is shown below in Figure 18. In addition to the altered shape of the wheel
attachment hole, the team designed an additional wheel shape to further increase ease of rotation.
The new wheel was designed with four spokes, which allows the user to hook his or her finger in
between the spokes and rotate the device. The spoked wheel was mainly designed with
manufacturing purposes in mind (i.e. for a universal device). However, the client will receive a
spoked wheel as well as a regular wheel, and he will chose which wheel he wishes to have on his
device. The client will be provided multiple wheels with Dycem in case of failure of either the
Dycem or of the wheel slipping off.
Figure 18: Modified square wheel holes to prevent slipping
The overall versatility of the device was tested using the client’s thickest/widest fork and the
thinnest fork that the team could find. These utensils were inserted into the device, and the ease of
rotation was observed. The thick fork was more difficult to insert and remove than the thin fork but
was held tighter in the foam. The thin fork was easily inserted and removed and only had minimal
sliding within the device during use. The test also showed that thicker forks require slightly more
work to rotate the pin.
The final test was to determine how well the foam would secure the utensils in within the device.
A 24.1 gram spoon was inserted into the foam. Weights were tied to the head of spoon, and the
device was held upside down to test if the spoon would slip from the grip of the foam. The foam
47
held up to a total of 54.1 grams before the spoon fell. The heaviest spoon found on the market was
45.6 grams, so the foam should sustain a secure hold on utensils of any weight. In addition, the client
never holds the device directly vertical during use, so the added balancing force of the bottom pin
further secures the utensil during use. After testing the device for possible modes of failure, the team
is confident that the final device satisfies all client needs and will hold up after being used daily for a
long duration.
10.0 Conclusions and Recommendations The Fork and Spoon design team set out to create a device that would assist our client with CMT
disease in eating independently despite his lack of finger and wrist mobility. Assistive eating devices
on the market are not universal and only fit specific utensils. Additionally, they are held in a fixed
position without the ability to rotate as required by our client. At the start of the project, the client
used a device designed by past Penn State students. It rotated via a spring and gear mechanism,
which lead to internal wear on the components. The utensil could only be inserted and removed
when the pin piece was in a neutral position. In addition, it only rotated in one direction in 45 degree
increments and produced a loud clicking noise with each rotation. The team’s objectives for the
semester were to increase the durability of the device by introducing a new rotation mechanism,
increase the versatility of utensils that could be inserted into the device, and to increase the security
of the utensil within the device to reduce wiggling.
The team implemented a new rotation mechanism to freely rotate a utensil 360 degrees in both
directions to any desired angle and to increase the durability of the device. The new rotation
mechanism was applied through two different prototypes. The first included a mechanism by which
a key block on the terminal device fit into a key hole on a separate piece attached to the client’s
opposite wrist. The second prototype excluded the key hole piece and instead included an attachable
wheel on the bottom of the key block. The client could roll the wheel on the base of the device on his
opposite hand to easily rotate the utensil to a desired position. The client preferred the roller device
as the turning motion required for the key block model was too strenuous on his shoulder.
Additionally, to increase utensil versatility and security, the team incorporated medical foam and
widened the pin to keep utensils in place and to accept a greater variety.
The client and the sponsor have both showed high satisfaction with the solution that the final
design proposes. Further additions to the design could over-complicate an overall simple design for a
complex problem. If improvements are made, a rest for the clients thumb could be implemented. The
team attempted to create a thumb rest, but it was too uncomfortable for the client so it was removed.
A new version could be created that better suit the customer needs. In addition, the ABS plastic
primarily used in the design’s structure is able to be 3D printed and is durable and cost effective;
however, higher quality materials could be used to increase the longevity of the device even further.
Lastly, other materials could be added to the device to increase friction of the rotation mechanism.
The team discussed with the sponsor the potentiality of marketing the device in the future. Four
main considerations were formulated. The first was coating the roller wheel with rubber dip instead
of Dycem. The second was coating the foam with latex instead of superglue. Both the first and
second considerations would speed up the manufacturing process and eliminate tedious tasks that
currently exist. The third consideration was selling the device with differently shaped wheels (i.e.
smoothed versus spoked). Depending on the condition, potential customers who would be using this
48
device could vary in their mobility and find one wheel easier to use than another. The final
consideration made by the team and the sponsor was selling the device along with a specific fork and
spoon. By doing so, the device would be guaranteed to securely hold this set of utensils, despite
being fairly versatile with others on the market.
In conclusion, the roller device and was customized to fit the client’s specific needs. The team
made adjustments to the device’s dimensions to make the rolling mechanism more comfortable and
convenient. The new device is easy to use, durable, and quiet, while offering multidirectional
rotation in 360 degrees. Furthermore, it includes no neutral position necessary for insertion and
removal of the utensil, and it secures utensils of all sizes. The total cost to manufacture the final
design is ~ $40.00. The client is happily using this device as of April 2015 for daily meals both at
home and in public.
* The team would like to note that Marty made a last minute request to remove the dropdown
extension piece on the outer casing. After he began to use the device, he decided that he could not
get used to the device being further away from his palm. As a result the team provided him with a
new device without the dropdown piece to satisfy his needs. CAD drawings of the assembled model
without the dropdown piece can be seen in Appendix K.
11.0 Self-Assessment (Design Criteria Satisfaction)
11.1 Customer Needs Assessment
Throughout the entirety of the project, our team has focused on refining and satisfying the needs
of our customer. Our number one priority was to make the device easy to use for our client. In
addition, we focused our efforts on the functionality and durability of the device. To self-assess our
team on meeting these customer needs, 9 out of 10 would be appropriate. From an ease of use
standpoint, the device allows the user to insert and remove silverware almost effortlessly. Once the
silverware is inserted, the utensil can be rotated with a minimal amount of work by rolling the wheel
along the customer’s opposite hand. The functionality of the device has also been met. The fork and
spoon holder allows various sizes of utensils to be held securely while still being able to rotate the
way it was designed. The removal of gearing previously used to rotate the device has also made the
device much more durable than previous designs. All in all, the customer needs have been met on a 9
out of 10 basis; the device satisfies all needs with the exception that all designs can be improved.
11.2 Global and Societal Needs Assessment
As stated in Section 11.1, our team has made our client, Marty, our main priority. His happiness
with us and with our device was extremely important to our project’s success. We prioritized
listening to his needs and noting each one because our team truly wanted to provide him with a
device that he would enjoy using by the end of the semester. Because we kept Marty always at the
front of every new design choice, we excelled in meeting the basic human needs and safety for the
project. Additionally, we found ourselves solving problems involving bioethics. At times Marty
would suggest problems with the design that were very specific for his needs - sometimes these
suggestions would cause us to start from scratch (i.e. a new method for smooth multidirectional
rotation) or make changes that could put us weeks behind as a team (i.e. a method for lowering or
raising the utensil). As a team facing these challenges, we had to weigh the pros and cons and make
the most ethical choice for Marty and for ourselves - what was worth the risk, time, and money
49
versus what was not. Could we still provide Marty with a device that satisfied most of his needs, and
kept us from failing as a team? We overcame those bioethical issues, and succeeded. Unfortunately,
we failed to think much about the environment. We printed over $500 worth of plastic throughout
our prototyping stage, utilizing energy and material that might not have been as necessary if we were
more careful and tedious with our concept generations and modifications. As a result of it all, our
team would give ourselves 9 out of 10 for meeting global and societal needs.
References
[1] NIH, “Charcot-Marie-Tooth Disease Fact Sheet,” National Institute of Neurological Disorders
and Stroke. June 2013.Retrieved February 5, 2015 from
http://www.ninds.nih.gov/disorders/charcot_marie_tooth/charcot-marie-tooth_fs.pdf,
[2] POSNA, “Charcot-Marie-Tooth Disease,” American Academy of Orthopaedic Surgeons. Feb.
2014. Retrieved February 5, 2015 from
http://orthoinfo.aaos.org/topic.cfm?topic=A00706
[3] Milton S. Hershey Medical Center, “Support Groups,” 2013. Retrieved February 5, 2015 from
http://www.pennstatehershey.org/web/guest/community/classessupportgroups
[4] Palmar Clip ADL Cuff. Retrieved February 2, 2015, from
http://www.alimed.com/palmar-clip-adl-cuff.html
[5] Fabrication Enterprises Utensil Holder. (n.d.). Retrieved February 2, 2015, from
http://www.devinemedical.com/Fabrication-Enterprises-Inc-61-0112
Utensil-Holder-p/fab1-61-0112.htm
[6] Utensil Holder With Elastic Opening. (n.d.). Retrieved February 2, 2015, from
http://healthproductsforyou.com/p-28265-utensil-holder-with-elastic
opening.html
[7] Grip Solutions Hand Grip. Retrieved February 2, 2015, from
http://www.wrightstuff.biz/grip-solutions-hand-grip.html
[8] Right Angle Utensil Pocket. Retrieved February 2, 2015, from
http://www.allegromedical.com//daily-living-aids-c519/right-angle-pocket
[9] Utensils. Retrieved February 2, 2015, from
http://www.especialneeds.com/dining-utensils.html?page=2
[10] iArm. Retrieved February 2, 2015, from
http://www.assistiveinnovations.com/index.php/en/ourproducts/robotics/iarm
50
Appendices Appendix A: Patent Descriptions
The following patents are relevant to the Penn State fork and spoon devices:
1) US 3288115 A: Ball-point pen mechanism
This patent describes a ball-point pen mechanism, and more importantly, the concept of
protracting and retracting the ink cartridge within it. This patent is relevant to the past design
because the rotating mechanism of the utensil is based on the protracting and retracting
events that occur with a retractable pen.
2) US 5630276 A: Eating utensil
This patent describes an eating utensil that is made for people with disabilities so that they
can feed themselves. It maintains the idea of a self-leveling spoon. This patent is relevant
because the idea for the internal rotating hardware is based off of the gears in this eating
utensil.
3) US 659341 A: Self-leveling spoon
This patent describes a utensil’s ability to self-stabilize. Due to its weighted bottom, the bowl
of the spoon maintains its level when the device is held. This patent is relevant because the
clamp with which the utensils are fastened is similar in shape to the self-leveling spoon.
4) US 4389777 A: Eating utensil for use by the manually impaired
This patent describes a device that allows a utensil to be secured into an instrument base.
This patent is relevant the entire attachment concept of the past design is based on this
invention.
5) US 2012147 A: Chuck operating key
This patent relates to the key and chuck mechanism seen in drills. The invention involves
inserting a key into a chuck, causing rotation within the drill. This patent is relevant because
it explains the concept that the rotating mechanism is based off of for the new design.
6) US 1136839 A: Car wheel
This patent describes a car wheel that rotates when a center bar, perpendicular to the wheel,
is moved by inner mechanics of the car. As far as the art-function matrix goes, this patent
affects the mechanical, aesthetic, and technical design of the device.
Patents 1 through 4 are relevant to the past fork and spoon device. Patents 2,3, and 5 are relevant
to the new fork and spoon device. Patent 6 is relevant to the rolling rotation mechanism.
51
Appendix B: Detailed Existing Product Summary
These are the major assistive eating devices currently on the market today. Each one is classified
as a cuff, adaptive utensil, or robot. The prices are listed if applicable and available.
1) Alimed - “Palmar Clip ADL Cuff” [4]
Classification: Cuff
Cost: $25.75 This device is a strapless device that slides onto the hand
and uses spring action to hold utensils. The pivoting
pocket permits more effective utensil position than
devices with a fixed pocket.
2) Fabrication Enterprises – “Utensil Holder” [5]
Classification: Cuff
Cost: $5.00
This device is an eating aid for people who have trouble
grasping and holding small utensils. The spring action
plastic clip fits the hand snugly without pinching, and
the utensil is held in a fixed position through a slit in the
cuff fabric.
3) “Utensil holder with elastic opening” [6]
Classification: Cuff
Cost: $12
Allows all utensils with hooks to be inserted into the
cuff. The Velcro hook and loop provide easy closure.
The beige cotton webbing is durable for long-term use.
52
4) Grip Solutions – “Hand Grip” [7]
Classification: Cuff
Cost: $37.95
The material of the device is a no slip, non-sticky one.
There are four different slits of various sizes, which
eliminate the need to ever have to adjust. It can fit a
variety of items, ranging in size from a pen to a
hairbrush.
5) “Right Angle Eating Utensil” [8]
Classification: Cuff
Cost: $20
This device allows an inserted utensil to be positioned at
a right angle to the palm. It accommodates standard
eating utensils, but not all sizes. The device is fabricated
using a combination of leather and metal materials. It is
one of the only products on the market that allows the
user to have some angled movement while eating.
6) “Assistive Dining Utensils” [9]
Classification: Adaptive utensils
Cost: $10 per set (on average)
These devices have large grips, creating an easy hold.
Many are designed for people with unsteady hands or
arthritis. Some utensils come angles, while others do not
– it all depends on the product brand.
53
7) Assistive Innovations – “iArm” [10]
Classification: Robot
Size: $100s-1000s
iArm is a robotic assistive eating device. In order to
move the hand around, the user needs to control a
joystick to feed oneself. The spoon used in the device
is customized and cannot be changed. It is a big,
black, bulky piece of equipment used by many
confined to wheelchairs.
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Appendix C: Budget Table
Item Cost (Dollars)
Bill of Materials 112.30
Prototyping 541.84
3D Printer Usage 541.84
Travel 192.25
Poster 65
Total 911.39
Appendix D: Bill of Materials
Item Number Description Vendor Quantity
Cost per
Item
(Dollars)
Total Item
Cost
(Dollars)
10333024
Suction Cup
Combo Michaels 1 3.49 3.49
10597609 Foam Sheets 12x18 Michaels 1 0.99 0.99
46232
Velcro 3/4"x12'
black Lowes 1 8.97 8.97
1037357
Kunin 9x12 white
felt Jo Ann 2 0.49 0.98
xprd821459 Darice 9x12 foamie Jo Ann 1 0.89 0.89
zprd_04700415a
Darice 9x12 ex
thick black Jo Ann 1 1.99 1.99
8514721 Suzh navy sd solid Jo Ann 1 2.12 2.12
5734272
Nipk swimwear
lining nude Jo Ann 1 1.25 1.25
13856687
Nipk confetti multi
ity k Jo Ann 1 1.31 1.31
50-1560B
Dycem non-slip
adhesives strips
(16"x1-1/8) Amazon 1 13.99 13.99
56060984
Memorex CDs (10
pack) Target 1 6.35 6.35
538301 Plasti-dip spray Lowes 1 6.34 6.34
75815116031 Plasti-dip liquid
Home
Depot 1 7.40 7.40
N/A Shipping of device FedEx 1 56.23 56.23
Total 112.3
55
Appendix E: Gantt Chart
56
Appendix F: Resumes
57
58
59
60
61
Appendix G: Deliverables Agreement
62
Appendix H: Design Changes since the SOW Report
Engineering Specifications
Table H.1: Revised Target Specifications and Values
Metric Importance Target Value Units
Cylinder Length 6 9.2 cm
Cylinder Outer Diameter 1 2.8 cm
Cylinder Inner Diameter 1 2.6 cm
Top Cap Length 1 1.8 cm
Top Cap Outer Diameter 1 3.5 cm
Top Cap Inner Diameter 1 3.2 cm
Bottom Cap Length 1 1.8 cm
Bottom Cap Outer Diameter 1 3.5 cm
Bottom Cap Inner Diameter 1 3.5 cm
Key Block Length 5 3.5 cm
Key Block Width 5 1.5 cm
Key Block Thickness 9 2 cm
Key Hole Length 5 3 cm
Key Hole Width 5 1.5 cm
Key Hole Thickness 9 3 cm
Pin Length 3 8 cm
Pin Width 7 3 cm
Concept Generation and Selection
During initial testing with the client of the key hole and block prototype, it was found that the
client could use the rotation mechanism successfully when the key hole was attached to the opposing
hand. However, the amount of work that the client had to put in did not result in fast enough rotation.
The client expressed that with the amount of shoulder force needed to rotate the utensil just a small
amount he would lose stamina. The team decided to find a way to rotate the utensil with less effort.
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During testing with the client, an idea was generated to possibly add a rubber wheel to the bottom of
the device for easy rotation. The client could easily roll the device along the table edge or on the side
of his pant leg to adjust the angle of the utensil. The team had the client practice this motion of
rolling the terminal piece along the table, and the client expressed great interest in this prototype
design. A sketch of the rolling wheel concept can be seen in Figure H.1.
Figure H.1: A rolling wheel attachment on the base of device to increase ease of utensil
rotation and eliminating unnecessary shoulder force.
Another issue that was brought up during discussion with the client was that his thumb drags in
his food while eating due to the positioning of the device on the splint. The team suggested
extending the device and possibly lowering the device away from the splint so that the client can
place his thumb on top of the piece while eating to reduce dragging. The thumb would rest more
naturally on top of the device and would also help reduce wiggling of the utensil by helping to hold
the fork in place. Figure H.2 shows the team generating this concept with the client and determining
how long to extend the device to solve this issue.
64
Figure H.2: Client’s thumb drags in food. The team measured how much to elongate the
terminal piece to address this issue.
As stated above, the client had a difficult time rotating the utensil with the key hole and block
design due to deteriorating shoulder strength. When discussing initial testing of this prototype with
the sponsor, the team (including the sponsor) decided to continue to simultaneously work on
improving the key hole and block prototype as well as designing the new roller prototype. The
sponsor sees promise in the key hole and block design for other patients that are not as far along in
the progression of the disease. During testing with the client, the Velcro straps that attached the key
hole piece to the opposing hand were not tight enough to stop the device from moving around on the
hand. The team came up with a design idea to place the device on the side of the wrist, which would
be more of a natural position for the client. In addition, if this piece was designed to fit over the side
of the wrist in a semi-circle shape, the piece would not be able to slide around during use. A sketch
of this design concept is seen in Figure H.3.
Figure H.3: Block piece moved to the side of the wrist to reduce wiggling during use.
The two pin inserts were also tested during the meeting with the client. The fabric pin was too
difficult for the client to insert utensils. This concept has therefore been eliminated from future
65
design plans. The tapered pin accepted and held some utensils during testing; however, with the
foam inserts, the pin did not accept the client’s thickest utensil. To address this issue, the team will
increase the pin gap to accept thicker utensils.
System Level Design
The pin insert was modified to allow a wider range of utensils to fit inside the prongs and can be
seen in Figure H.4. By widening the overall gap from 2 mm to 5 mm, almost all thicknesses of
silverware should fit inside the prongs. Open-cell foam will be added to the inside of one or both
pins to mold around the silverware and hold the utensil more securely. By using foam that can be
easily compressed, the insertion and removal of the silverware also becomes much easier.
Figure H.4: Widened pin with added room for foam inserts.
The key block device was modified to improve ease of use and functionality. The outer shell was
extended 20 mm to allow the user’s thumb to rest on top of the device. With the previous shorter
design, the user’s thumb rested underneath the device and often came in contact with food on the
plate. To compensate for the additional 20 mm length of the shell, the upper piece of the key block
was extended by 20 mm. The key hole attachment was also redesigned to offer better usability. The
radial arc was ergonomically redesigned to be placed on the inside of the user’s wrist. The key hole
was extended to provide a deeper pocket for the key block could be inserted and rotated. These
adjustments can be seen in Figure H.5.
Figure H.5: Exploded view of key block device
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When testing, a slightly different prototype was generated. This design does not use a key block
system, but rather a roller. The terminal device is essentially the same, except that the square bottom
of the key block is traded for a round cylinder. This cylinder is then locked into the hole in the wheel
piece. To rotate the inner pin, the user pushes the wheel against the edge of a table or pants leg, and
moves the device laterally in either direction. By adding Dycem to the wheel, the friction
encountered between the wheel and table edge or pant leg induces rotation when moved laterally.
This system reduces fatigue, as well as significantly enhances ease of use. This design can be seen in
Figure H.6 below.
Figure H.6: Exploded view of wheel device
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Appendix I: Design Changes since the DSR
Engineering Specifications
Table I.1: Revised Target Specifications and Values
Metric Importance Target Value Units
Cylinder Length 6 6.4 cm
Cylinder Outer Diameter 1 2.8 cm
Cylinder Inner Diameter 1 2.6 cm
Cylinder Extender Piece 5 1.0 cm
Top Cap Length 1 1.8 cm
Top Cap Outer Diameter 1 3.2 cm
Top Cap Inner Diameter 1 2.9 cm
Bottom Cap Length 1 1.6 cm
Bottom Cap Outer Diameter 1 3.5 cm
Bottom Cap Inner Diameter 1 3.5 cm
Pin Length 6 14.5 cm
Pin Width 7 2.4 cm
Pin Square Attachment Block 5 1.0 cm
Roller Wheel Diameter 5 3.2 cm
Concept Generation and Selection
After initial testing with the roller mechanism prototype, the client was very happy with the
design. The team had both extended the device and added a dropdown piece to allow the user’s
thumb to rest more comfortably on top of the device to avoid dragging in food. Instead of solely
resting on top of the cap piece of the device, the team considered designing a thumb rest for the user
to place his thumb into. This thumb rest would be attached to the cap and would resemble a J-hook.
A basic sketch of what this concept would look like is shown below in figure I.1.
68
Figure I.1: Sketch of thumb rest concept
The team designed this thumb hook in SolidWorks and 3D printed a modified cap in the Learning
Factory. During client assessment of the thumb rest prototype, the team discovered the client’s
thumb was locked in a position that made using the thumb rest too uncomfortable. The thumb rest
was also too brittle due to being thin and extruded from the device. A SolidWorks model of the
thumb rest prototype can be seen in Figure I.2 below. The client decided against a thumb rest and
would rather just rest his thumb on top of the device.
Figure I.2: SolidWorks model of thumb rest roller prototype
System Level Design
The final design of the fork and spoon holder is shown below in Figures I.3 and I.4. A few
changes were made from preliminary prototypes to enhance the ergonomics and functionality of the
device. The device now consists of just 4 pieces in total. A dropdown was added to the outer shell to
extend the device a few centimeters from the user’s palm. This would allow for the user’s thumb to
rest above the device when in use, keeping the thumb clear of any contact with the contents of the
plate. This dropdown was made hollow as opposed to solid in order to make the device lighter and to
reduce material and cost. The shell was also shortened, to provide a better angle for when the client
uses a stabbing motion. The shorter the shell, the less the client has to raise his shoulder to provide
the right angle to stab a piece of food. The inner pin and lower cylinder were combined into one
piece for two reasons. For one, the reduction in the number of pieces makes the design simpler, in
addition to removing the need for any gears-a possible mechanism for failure. The slot in the pin has
69
also been extended to allow the utensil to be inserted farther. This extra length within the slot not
only holds the utensil more securely, but further aids in reducing the stabbing angle needed by the
client. Medical grade T-foam is cut and inserted into the pin to compress the utensil against the
opposite wall of the pin. The smooth adhesive backing on one side of the foam allows for the utensil
to be inserted and removed easily, while still compressing the utensil when fully inserted. The
bonding of the wheel and inner pin has also been modified. The wheel and lower cylinder now use a
square shape to join the two pieces. This will prevent any slippage between the wheel and pin,
keeping a constant connection between the wheel, pin, and ultimately the utensil.
Figure I.3: Exploded view of final prototype
Figure I.4: Assembled view of final prototype
70
Appendix J: Past CAD Drawings
Figure J.1: Assembled specification drawing of key block device (mm)
Figure J.2: Assembled specification drawing of wheel device (mm)
71
Figure J.3: Specification drawing of shell (mm)
Figure J.4: Specification drawing of the cap (mm)
72
Figure 23: Specification drawing of cap
Figure J.5: Specification drawing of cylinder key block (mm)
Figure J.6: Specification drawing of square key block (mm)
73
Figure J.7: Specification drawing of pin insert without foam (mm)
Figure J.8: Specification drawing of key hole wrist piece (mm)
74
Appendix K: Final CAD Drawings
Figure K.1: Assembled specification drawing of final roller device with extender piece (mm)
Figure K.2: Specification drawing of final roller device outer shell with extender piece (mm)
75
Figure K.3: Specification drawing of final roller device pin (mm)
Figure K.4: Specification drawing of final roller device cap (mm)
76
Figure K.5: Specification drawing of final roller device round wheel (mm)
Figure K.6: Specification drawing of final roller wheel device spoked wheel (mm)
77
Figure K.7: Assembled specification drawing of final roller wheel device without extender
piece (mm)
Figure K.8: Specification drawing of final roller device outer shell without extender piece
(mm)