Department of Electronics and Mechanical MECH690...

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Department of Electronics and Mechanical

MECH690 Mechanical Design Project, Summer 2010

Final Report

VERSATILE MECHANIC’S CREEPER

Project Manager: Mathew D. Hudon Signature: ____________________ Date: ______

Team Member: Christopher J. Llanes Signature: ____________________ Date: ______

Team Member: Andrew S. McDonough Signature: ____________________ Date: ______

Team Member: Timothy J. Rachielles Signature: ____________________ Date: ______

Project Advisor: Xiaobin Le

Department of Electronics and Mechanical Wentworth Institute of Technology

550 Huntington Ave, Boston, MA 02115 August 6, 2010

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Table of Contents

Summary of Project……………………………...……………………………………………..…4 Executive Summary.…...…………………………………………………………………….……5 1.) Introduction……..…………………………………………………………………………..…6

2.) Needs Assessment….…………………………………………………………….……………7

3.) Design Specifications……………………………………………………………….…………8

4.) Design Options……………….…………………………………………………………..……9

4.1.) Analysis of Design Options…………………………………………………….……9

4.2.) Decision Matrix………………………………………………………………….....13

5.) The Design of the Project………………………………………………………………...…..14

5.1.) Mechanical Analysis and Calculations………………………………………...…...15

5.2.) Experimental Results and Analysis………………………..……………………….19

5.3.) Assembly Tolerance and Part Dimensions………………………………………....22

5.4.) Manufacturing Routing………………………………………………………….….22

5.5.) Cost of Parts………………………………………………………………………...23

5.6.) Assembly and Detail Drawings…………………………………………………….24

5.7.) Construction Photos………………………………………………………...………42

6.) User Manual…………………………………………………………………………….……48

6.1.) Parts List……………………………………………………………………………48

6.2.) Operation Instructions and Maintenance…………………………………………...50

7.) Conclusions……………………………………………………………………………….….52

8.) References………………………………………………………………………………...….52

9.) Appendices………………………………………………………………………………...…52

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9.1.) Team Qualifications………………………………………………………………..52

9.2.) Resumes of Team Members…………………………………………………….….54

9.3.) Weekly Working Notes of the Group………………………………………………60

9.4.) Samples of Engineering Notebooks of Team Members………………………...….72

9.5.) Breakdown of Tasks………………………………………………………………..80

9.6.) Group Schedule and Progress………………………………………………...…….80

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Versatile Mechanic’s Creeper

Summary of Project

The main goal of this mechanical design project is to improve a product that currently

exists on the market. We do not aim to reinvent such a valuable tool used by mechanics,

however intend to ease their everyday working conditions by making it easier for them to work

under the car.

The main objective for our creeper design is to make the mechanic capable of adjusting

the backrest of the creeper to different angles while lying down on the creeper. Current designs

require you to roll out from under the car, get off the creeper and adjust the backrest, and then

roll back under the car. This design will save time for the mechanic and increase his/her work

efficiency. This product will be geared towards the small garage owner or mechanic who cannot

afford a carlift and only has the capability of putting their car on jack stands.

After design and analysis is complete, we will build a prototype model that will

incorporate all of our design specifications, including such criteria as keeping the weight down

and keeping the cost low. We will accomplish this all while building a strong and practical

design.

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Executive Summary Breakdown of Tasks Mathew D. Hudon

! Main frame design and analysis ! Technical report writing

Christopher J. Llanes ! Design and analysis of scissor lift mechanism ! Helping with technical reports

Andrew S. McDonough ! Design and analysis of backrest subassembly, as well as input on drive system ! Helping with technical reports.

Timothy J. Rachielles ! Design and analysis of drive system, as well as input on scissor lift mechanism ! Helping with technical reports.

Performance of Team Members

Each group member completed the tasks they were assigned by the deadline they were

given. The work was split up among team members equally and the work distribution was

agreed upon by every group member. Everyone was punctual and contributed to all meetings.

Group presentations were rehearsed before all presentation dates. Manufacturing was done by

all members. A plan was laid out assigning specific components to be manufactured by each

group member. The group worked smoothly together and we are all happy with each other’s

performance and willingness to put in extra time and effort in order to complete the project.

Project Manager: Mathew D. Hudon Signature: ____________________ Date: ______

Team Member: Christopher J. Llanes Signature: ____________________ Date: ______

Team Member: Andrew S. McDonough Signature: ____________________ Date: ______

Team Member: Timothy J. Rachielles Signature: ____________________ Date: ______

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1.) Introduction

Many automotive enthusiasts, “do-it-yourself-ers”, and mechanics use what is called a

“creeper” every day. It is essentially a platform on wheels to help you slide in and out from

underneath a car. The idea to redesign the creeper came about during a routine automotive

repair. The creeper being used was uncomfortable, non-adjustable, and was overall difficult to

use to the point where it was questionable whether or not to even use one. Then, while sitting in

a La-z Boy recliner, the thought of “why can’t

someone be this comfortable while working under a

car?” came to mind. It has almost become accepted to

be uncomfortable while working underneath a car, and

this is what we are out to change.

To redesign something that already has such a

large presence in the market today is challenging and

requires a lot of research. Some of the design concepts

that have been discussed to raise the back were a pneumatic piston, a pneumatic balloon that

inflates, hydraulic piston, electronic motor, a ratchet system like in a come-along, and a hand

crank attached to a scissor lift. The creeper will have additional items that will make it more

pleasurable to use, such as work lights to see underneath the

car, and magnetic tools/parts trays to keep items at the ready.

This design will help us recreate the creeper and make it as

comfortable as possible while allowing ease of use and

keeping the cost down.

Figure 1. Current creeper used in industry

Figure 2. Original Creeper design

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2.) Needs Assessment

Our project is a new take on an old classic, the automotive creeper. Current automotive

creepers do not offer much in the way of features or even comfort and we aim to solve this

problem by incorporating some unique design features. Automotive creepers today are often not

designed with human ergonomics in mind causing lower back, neck, and shoulder strain, which

in turn causes less time working and possible minor injury. With an adjustable backrest and

head rest system, those problems will be alleviated.

Versatility is also a main concern of ours. To solve this problem, a lighting system and

tool and hardware storage system will increase time spent working, instead of sliding in and out

from under the car. The technology behind our design exists and is easily accessible to the

public. However, our design will bring profit to the potential client due to the unique design

features that no other product on the market has today. Our team is comprised of automotive

enthusiasts who are all mechanically proficient with excellent hands-on, practical, backgrounds.

After conducting a survey, we found a trend among fellow automotive enthusiasts in

what they want out of an automotive creeper. The bulk of the people who responded do most of

the work done to their own cars, meaning they don’t normally bring it to a shop and that they

normally do not use a creeper because they are constructed poorly, are inconvenient, and are

poorly designed. Most people found the quality of build, reliability, comfort, and options to be at

the top of their list when considering the purchase of a creeper. Several people actually

described our project without them knowing what our plan was to design. Weight and cost were

two of the least important things selected among the survey takers.

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3.) Design Specifications

Creepers on the market today fail to meet the requirements of DIY mechanics and car

enthusiasts alike. A survey was conducted to determine the needs of the common creeper user.

From the survey results we were able come up with design criteria to meet our needs assessment.

Most of the survey responses requested comfort and functionality as a must. Due to this request

we will not only design a strong and functional creeper, but also one that improves upon the

comfort of current creepers on the market. The design specifications for our creeper design are

as follows:

! Design Load: 300 lb

! Factor of Safety: 2

! Backrest Lift Angle: 45 degrees

! Length x Width: 48 in. x 28 in.

! Total Weight : 25 lb

! Caster Size: 3.5 in.

! Memory Foam Padding for entire creeper

! Oil resistant fabric to protect Memory Foam Padding.

It is important to note that, for the use of this creeper, the following boundary conditions

must be present:

! Car must be sitting on jackstands with a minimum ground clearance of 2 feet.

! The floor that the creeper will roll on must have a hard surface that will accommodate a creeper

ground clearance of 1.25 inches.

These parameters are described in Figure 3:

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Figure 3. Boundary Conditions

4.) Design Options To satisfy the main design criteria of adding a lifting mechanism to the backrest of a

creeper, we developed several design options. The main ideas we came up with to solve this

problem are of the following:

1.) Pneumatic piston

2.) Hydraulic piston

3.) Inflatable bag

4.) Scissor lift

5.) Ratchet system (come-along)

6.) Spring with locking capability

4.1.) Analysis of Design Options

Option 1 – Pneumatic piston

This design option would involve fastening a piston-cylinder to the main frame and,

through manual operation of a bicycle pump, the piston would extend outward and therefore lift

the backrest. Another way of getting air into the cylinder would be through the attachment of an

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airhose to the creeper. However, this could impose problems due to the fact that you may roll

over the hose with the creeper.

Option 2 – Hydraulic piston

The hydraulic piston would act on the same principle as in Option 1, however hydraulic

fluid would be forced into the cylinder. We have come across a problem when trying to figure

out how these type of piston systems could work. Because the creeper has such a low profile and

there is limited space, it is hard to mount the piston at an angle where the force would be

somewhat normal to the backrest. When the piston is mounted in a horizontal position on the

same plane as the main frame, it is hard to get a y-component force out of the piston.

Figure 4. Pneumatic or Hydraulic Piston concept.

Option 3 – Inflatable bag

This inflatable bag would be mounted behind the backrest. When air would be pumped

into the bag, the volume would increase, therefore lifting the backrest. This would also require

the attachment of an airhose.

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Figure 5. Inflatable Bag concept.

Option 4 – Scissor lift

The scissor lift would be mounted on the main frame behind the backrest. A main

concern with a scissor lift is that it usually only lifts something that is normal to where it is

extending. However, we would propose the idea of modifying the top plate of the scissor lift

where there would be a pin that slides in a slot that has been machined into the backrest. This

would account for the changing angle of the backrest relative to the scissor lift. The lift would

extend and contract due to a threaded rod connected to the bottom of the lift, which would be

driven by a crank and driveshaft mechanism (user operated).

Figure 6. Scissor lift concept.

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Figure 7. Solidworks model of our scissor lift concept.

Option 5 – Ratchet system (come along)

This system would have a hand crank with gears and chain and, through the efforts of the

user, would gradually lift the backrest. The crank would have a ratchet mechanism. The chain

would connect the hand crank to a gear mounted on the backrest pivot.

Option 6 – Spring w/ locking capability

This would involve attaching an axial spring near the pivot of the backrest. When the

backrest is horizontal, the spring would be locked, exerting no force on the backrest. If the user

wanted to increase the angle of the backrest, the spring would be unlocked.

Options 1, 2, and 4 will be investigated further through research and development.

Option 4 seems very practical to us, however 1 and 2 are definitely in consideration because a

piston can definitely provide more than enough force to lift the back rest.

The main frame of the creeper must be strong, lightweight, and relatively cheap to build.

Therefore, we have developed 3 design options for the frame:

1.) 1/16” wall, 1”x1” AISI 1020 steel tubing

2.) 1/16” wall, ¾”x¾” AISI 1020 steel tubing

3.) 1/8” wall, 1”x1” 6061 Al. tubing

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Also, for human ergonomic considerations, the padding used on the creeper must be oil

resistant as well as comfortable. Therefore, we are currently putting together ideas that would

include a memory foam style padding wrapped in an oil resistant material.

4.2.) Decision Matrix

Decision Matrix‐Lift Mechanism

Step 1: List options as rowsStep 2: Determine important attributes and add/remove columns, as appropriateStep 3: Assign relative weights to each attribute Step 4: Options with the highest scores should be considered

Scoring‐‐> 1‐5 pointsWeighing Factor 100.00 95.00 85.00 85.00 80.00 75.00 Option Cost Weight Low Profile Capabilities Availability of Parts Ease of use Total(Weighing Factor x Score)

Scissor 4 4 4 4 4 4 1829Pneumatic Cylinder 2 4 3 4 3 5 1790Hydraulic Cylinder 2 3 3 4 3 5 1695

Decision Matrix‐Frame


Scoring‐‐> 1‐5 points100.00 95.00 90.00 85.00

Option Cost Weight Strength Availability of Parts Total(Weighing Factor x Score)

1" x 1" 1/8" wall Steel 2 1 5 5 11701" x 1" 1/16" wall Steel 3 2 5 5 10103/4" x 3/4" 1/8" wall Steel 4 3 5 5 15603/4" x 3/4" 1/16" wall Steel 5 4 4 5 1665Aluminum 4 5 2 5 1480

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5.) The Design of the Project As described in the decision matrix section, we narrowed down our design options based

on criteria such as cost, weight, strength, availability of parts, capability of parts, maintenance,

etc. These factors were scored on a basis of 1 to 5 and then multiplied by a weighing factor

which gave a score indicative of our intentions for a final design. The final design parameters

are of the following:

! Lifting Mechanism: Scissor Lift

! Main Frame: ¾”x¾”, 1/16” wall AISI 1020 steel tubing

Decision Matrix‐Drive System


Scoring‐‐> 1‐5 points100.00 95.00 95.00 90.00 85.00 85.00

Option Cost Weight Durability Capabilities Minimum Maintenance Ease of Use Total(Weighing Factor x Score)

Drive Shaft 3 4 4 5 4 3 2105Chain and Sprocket 3 4 4 5 4 3 2105Pneumaitic pump 2 3 4 5 3 5 1995Hydraulic Pump 2 3 4 5 4 5 2080

Decision Matrix‐Sub Frame


Scoring‐‐> 1‐5 points100.00 95.00 90.00 80.00

Option Cost Weight Strength Availability of Parts Total(Weighing Factor x Score)

3/4" x 3/4" 1/16" wall Steel 4 4 5 5 16301/2" x 1/2" 1/16" wall Steel 5 5 4 5 1735

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! Drive System: Hand crank and driveshaft mechanism

! Sub Frame: ½”x½”, 1/16” wall AISI 1020 steel tubing

5.1.) Mechanical Analysis and Calculations Main Frame Strength Analysis

A strength analysis was performed on our main frame using Solidworks Simulation

software. A 300 lb distributed load was applied to the main frame while the caster hole locations

were restrained with a fixed geometry.

As described in the Decision Matrix section, the choice of tubing for our main frame was

based solely on weight, cost, and strength. The main frame will see a combination of static and

dynamic loading. Static loading situations call for a safety factor of between 1.25 to 1.5 and

dynamic loading situations call for a between 2 and 3. Therefore, we decided to design the

frame for a of 2.

The result of the static analysis was a maximum Von Mises stress of 24,674 psi, which

yielded a of about 2 relative to the yield strength of AISI 1020 steel.

Figure 8. Strength analysis using Solidwork Simulation software. Fixed geometry boundary conditions are set at the caster hole locations and a distributed 300 lb load is applied throughout the frame members.

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Torque Required to Raise Backrest When operating the Versatile Mechanic’s Creeper, a force F must be applied to the

ratchet wrench in order to produce a torque T to turn the drive system and raise the backrest. In

order to figure out the force required by the user, the torque must be calculated.

A few important boundary conditions must be mentioned in order to proceed with the

calculations. First, we can assume that half of the body weight of the user will be lifted by the

backrest, which, in this case will be 150 lb. Second, the ratchet wrench being used can be

assumed to have a moment arm length of 5 inches.

When the ½”-8 ACME threaded rod turns 1 revolution and the ACME nut that rides on it

travels 1 inch, the torque can be calculated by an equation provided by Machine Elements in

Mechanical Design, 4th Edition, Robert L. Mott:

(in-lb) Eq. 1

where,

F = force to be moved (lb.)

Dp = pitch diameter (in.)

f = coefficient of friction = 0.15 for lubricated screw

= lead angle =

= thread angle

plugging in values,

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The textbook also provides an equation to find the torque required to lower the load.

However, the torque required would be less than that of raising the load because of the effects of

gravity. Therefore, no analysis was necessary. We are only interested in the maximum force the

user would have to exert.

Now that the torque required to turn the screw has been found, we can calculate the force

required to turn the ratchet wrench by:

Eq. 2

This theoretical value doesn’t take into account the frictional effects in the moving parts

of the scissor lift, however gives us an idea of how much energy the user would exert.

Stress of Components due to Torque

Both of the drive shafts in our design that are used to transmit the torque have a diameter

of 3/8” at its smallest cross-section. Therefore, torsion and axial stresses can be calculated at

those cross-sections because this is where the maximum stress will occur. Using the T obtained

!"#$%!#&'()!'(*#+%*,"$'+)!"#'+(#!++'-'.",'/!'0*1,23

Eq. 3

An axial stress is also produced due to 150 lb load being moved, and can be calculated

by:

Eq. 4

Both of these stresses are negligible because the yield strength of AISI 1020 steel is

approximately 51,000 psi. It is important to note that the diameter of driveshaft used in our

design could have been smaller. However, due to design constraints and availability of parts,

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this was not an option.

How Many Cranks of the Ratchet Wrench Until Max Backrest Angle?

The maximum angle that the backrest of our creeper can obtain is 30 . To achieve this

desired angle, the ratchet wrench must be turned by the user a number of times. From an angle

of 0 to 30 , the ACME nut travels on the threaded rod a total distance of 5 inches. For each

revolution of the threaded rod, the nut travels 1 inch. Since the mechanic is expected to turn the

ratchet wrench in ¼ turn intervals, the number of ratchets can simply be found by:

Eq. 5

Shear Stress in Scissor Lift Pins

The max shear stress on the pins for the lift mechanism will occur when the mechanism is

completely closed and the cross members are fully horizontal. At this position the weight of the

backrest will be the force on the top of the pin while the frame itself will be acting as the reaction

force. With this information we can say that:

; where F=the force, and A=the cross sectional area.

Since the maximum weight we intend to be put on the backrest is 150 pounds and the

weight will be distributed on the 2 sides of the lift mechanism, the F in our case for one pin is 75

pounds. The factor of safety for our entire design is 2; therefore the shear stress must be

calculated using 150 pounds per side of the lift mechanism. The pin cross sectional area is

determined using its diameter of 0.5 inches.

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The shear yield strength is about 60% of the tensile yield strength for the material. The

yield for 1020 steel, which the pins are made of, is around 51,000 psi. Sixty percent of this is

around 30,600 psi. Comparing this value to the max shear on the pin, we can see that this value is

almost negligible.

5.2.) Experimental Results and Analysis Weight of Main Frame

After the design of the main frame was complete in Solidworks, we went to “Mass

Properties” and obtained the weight of it. The Solidworks value was 14.2 lb.

Figure 9. Weighing the actual main frame using digital scales.

After manufacturing the main frame using AISI 1020 steel tubing, the weight using

digital scales was 14 lb. This yields a very minimal percent error of 1.5%.

Total Weight

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Our design goal for total weight was to be 25 lbs. We were on track to meet this

requirement as the main frame weighed 14 lbs. After adding the drives system and scissor lift

components, the creeper weighed 24 lbs. The casters we ordered unfortunately weighed 11 lbs

and dramatically increased the total weight to 35 lbs. The casters were selected because they

were cheap and in turn, enabled us to complete the prototype.

We have developed several design options for the future to decrease the total weight in

order to make our product more marketable. Material can be taken away from certain

components of the creeper. Also, lightweight aluminum casters can be ordered as a replacement

to the heavy steel casters.

Torque Applied by Mechanic

As described earlier in the Mechanical Analysis and Calculations section, we

theoretically obtained a required torque of 32.6 in-lb to operate the creeper. However, we also

realized that this value may end up being higher due to the frictional effects in the gears and

scissor lift mechanism.

When attaching a torque wrench to the drive system, an actual value of 40 in-lb was

recorded.

Actual Maximum Angle Achieved

Figure 10. Schematic of actual creeper dimensions with the backrest at its maximum angle.

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Manufactured Prototype

Figure 11. Pictures of our manufactured prototype of the Versatile Mechanic’s Creeper.

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5.3.) Assembly Tolerance and Part Dimensions The manufacturing process we used could produce a tolerance of 0.001” at best.

Therefore, we classified our assemblies into tolerance classes such as Running or Sliding,

Clearance, Transition, Interference, and Force. We tried to machine our parts to meet the

requirements of each classification. The following table lists some components of our design

that we assigned these classifications to:

Table 1. Clearance types for each part and assembly description. Our part drawings were assigned a tolerance of 1/16” for fractional dimensions,

for 0.0 and 0.00 dimensions, and 0.010” for 0.000 dimensions.

5.4.) Manufacturing Routing

The Versatile Mechanic’s Creeper will be manufactured at N.C. Hudon Crane & Rigging,

Inc. in New Bedford, MA. The following diagram shows the procedure in which the creeper’s

parts will be manufactured:

Part Description Clearance Type

Sliding Pins for Scissor Lift Running Bushings in Bearing Tabs Force Driveshafts in bushings Transition Bevel Gears on Driveshaft Interference Spur Gears on Driveshaft Interference Pins in Scissor Lift Members Clearance Holes in Main Frame for Casters Clearance

Cut material using cut-off saw

Manufacture part via milling machine or lathe

Weld/Assemble Component

Ensure components work properly according to spec.

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Expected manufacturing time:

1. Cutting material is expected to take approximately 2 hours. 2. Manufacturing the components is expected to take approximately 15 hours. 3. Welding, Assembly, and Quality Control is expected to take 5 hours.

TOTAL: 22 hours 5.5.) Cost of Parts

Description Qty. Price Total

1018 Carbon Steel Precision ACME Threaded Rod 1/2"‐8, 1" travel/turn, RH Thread, 8 starts 1 $24.28 24.28 Bronze Precision ACME Round Nut 1/2"‐8, 1" travel/turn, RH Thread, 8 starts 1 $31.45 31.45 Steel Plain Bore 20 deg Angle Miter Gear 12 pitch, 15 teeth, 1.25" Pitch dia., 3/8" bore 2 $18.73 37.46 Galvanized Low‐Carbon Steel Rod 1/2" Diameter, 3' Length 1 $9.67 9.67 PTFE‐Lubricated SAE 841 Bronze Sleeve Bearing for 1/2" Shaft Dia., 5/8" OD, 3/8" Length 3 $0.62 1.86 PTFE‐Lubricated SAE 841 Bronze Sleeve Bearing for 3/8" Shaft Dia., 5/8" OD, 3/8" Length 6 $0.51 3.06 Steel Plain Bore 14‐1/2 Deg Spur Gear 20 Pitch, 20 teeth, 1" Pitch Diameter, 3/8" Bore 2 $16.14 32.28 Two‐Piece Clamp‐on Shaft Collar Steel, 1/2" Bore, 1‐1/8" OD, 13/32" Width 1 $3.22 3.22 Vinyl‐Coated Polyester Fabric 0.022" Thick, 61" Width, Black, 5' Length 1 21.20 21.20 Adhesive‐Backed Polyurethane Foam 1/2" Thick, 54" Wide Sheeting 3 $9.95 29.85 PTFE‐Lubricated SAE 841 Bronze Sleeve Brng for 3/8" Shaft Dia., 1/2" OD, 1/4" Length 10 0.42 4.20 PTFE‐Lubricated SAE 841 Bronze Sleeve Brng for 3/8" Shaft Dia., 1/2" OD, 1/2" Length 4 0.63 2.52 Lubrication‐Free Delrin Ball Bearing, SS balls, 3/8" shaft dia., 1‐3/8" OD, 7/16" Width 2 5.54 11.08 Steel Tubing, Flat Stock, and Misc. Material 1 75.00 75.00 Flat Black Spray Paint 2 5.00 10.00 4" casters, steel frames w/locks 6 9.14 54.84 3/8" Drive, Pear Head Ratchet 1 12.87 12.87 9/16" Deep Socket, 3/8" Drive 1 4.99 4.99 1" Corner Braces, Steel 16 0.50 8.00 300 1/2" Self Tapping Screws 1 4.98 4.98

Subtotal 382.81

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5.6.) Assembly and Detail Drawings

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5.7.) Construction Photos

Figure 12. Mat using the belt sander to de-burr a part that was cut on the lathe

Figure 13. Chris and Andrew using the mill to fabricate parts of the lift assembly

Figure 14. Mat Welding up portions of the back rest

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Figure 15. Mat welding some pieces of the main frame together

Figure 16. Tim using the chop saw to rough cut some stock before it goes to the mill

Figure 17. Chris measuring the holes out on the lift assembly

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Figure 18. Mat using the angle grinder with a cut-off wheel to rough cut some stock

Figure 19. Chris using the snap ring pliers to begin assembly of the lift mechanism

Figure 20. Chris test fitting the casters

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Figure 21. The main frame with the casters attached

Figure 22. Andrew cutting the wood for the stationary pad

Figure 23. Andrew applying spray adhesive to the vinyl before wrapping the pad

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Figure 24. Tim stapling on the vinyl to the pad

Figure 25. The final product for the back rest pad

Figure 26. The creeper with the pads mocked up

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Figure 27. The completed creeper showing the adjusted backrest

The prototype was constructed at N.C. Hudon Crane & Rigging, Inc. in New Bedford,

MA. This site was chosen because of the selection of tools and the ability to avoid the

overcrowding in the labs at Wentworth. It allowed the team certain luxuries otherwise

unavailable, like space, and a flexible schedule. It was manufactured by all members of the

team, each of whom had an equal opportunity to try each process required to build the prototype

such as welding, grinding, machining, and upholstery work. This allowed all members to gain

an appreciation for the process.

Certain things could certainly be changed about the manufacturing process. The

prototype produced has a few minor flaws due to the lack of precision that we were able to

achieve with the tools, materials, and time allotted. These errors could easily be fixed using

CNC, and a larger budget. Having more time would have also been a benefit to our construction

process; it would have allowed for more jigs to be made which would ensure a more precise final

product. Overall a working concept model was able to be created, and further precision will

alleviate most, if not all, of the problems encountered with the current prototype.

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6.) User Manual

6.1.) Parts List

Sub Assemblies

Item # Part # Description Qty.

010 80000 Main Frame 1 020 80001 Drive System 1 030 80002 Scissor Lift 1 040 80003 Back Rest 1

80000 Main Frame Assembly

Item

# Part # Description Material Quantity

010 00001 Outside Caster Tube, 3/4" square tubing AISI 1020 Steel 2 020 00002 Straight Come Down, 3/4" square tubing AISI 1020 Steel 6 030 00003 Modified Middle Cross Tube, 3/4" square tubing AISI 1020 Steel 1 040 00004 Middle Cross Tube, 3/4" square tubing AISI 1020 Steel 2 050 00005 Gusset, 1/16" thick steel AISI 1020 Steel 6 060 00006 Parallel Short Tube, 3/4" square tubing AISI 1020 Steel 2 070 00007 Parallel Long Tube, 3/4" square tubing AISI 1020 Steel 2 080 00008 Driveshaft Cross Tube, 3/4" square tubing AISI 1020 Steel 1 090 00009 Drive Support Tube, 3/4" square tubing AISI 1020 Steel 1 100 50000 Locking Casters, 4" diameter (swivel) N/A 6

80001 Drive System

Item

# Part # Description Material Quantity

010 00001 Bearing Tab, 1/2" thick, 1" width AISI 1020 Steel 3 020 00002 Long Bearing Tab, 1/2" thick, 1" width AISI 1020 Steel 1 030 50000 Sleeve Bearing, for 1/2" shaft #1688K14 Bronze 1 040 50001 Sleeve Bearing, for 3/8" shaft #1688K9 Bronze 4 050 00003 Threaded Rod Bearing Tab, 1/2" thick, 1" width AISI 1020 Steel 1 060 00004 Driveshaft, 1/2" diameter rod AISI 1020 Steel 1 070 50002 Threaded ACME Rod, 1/2"‐8 #99030A300 AISI 1020 Steel 1 080 50003 Spur Gear, 1" pitch dia., 20 teeth, #6325K83 Hardened Steel 2 090 50004 Bevel Gear, 1.25" pitch diameter, #6529K14 Hardened Steel 2 100 50005 3/8" Drive Ratchet Wrench w/ 9/16" socket Tool Steel 1 110 50006 1/2"‐8 ACME Nut, 8 starts Brass 1

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80002 Scissor Lift Assembly

Item # Part # Description Material Qty.

010 00014 Large Cross member, Plate 1020 Steel 2 020 00015 Small Cross member, Plate 1020 Steel 2 030 00016 Left Slider Bracket, Angle Iron 1020 Steel 1 040 00017 Right Slider Bracket, Angle Iron 1020 Steel 1 050 00018 Screw Bracket, Plate 1020 Steel 1 060 00019 Spacer, Rod 1020 Steel 2 070 00020 Internally Threaded Tube, Tube 1020 Steel 1 080 00021 Connector Pin, Rod 1020 Steel 4 090 00022 Slider Pin, Rod 1020 Steel 2

80003 Back Rest Sub‐Assembly

Item # Part # Description Material Qty.

010 00030 Backrest Side Bar, 1/2" x 1/2" Tubing, 0.047 wall, 22" long 1020 Steel 2 020 00031 Backrest Corner Bar, 1/2" x 1/2" Tubing, 0.047 wall, 6" long 1020 Steel 2 030 00032 Backrest Head Bar, 1/2" x 1/2" Tubing, 0.047 wall, 9.75" long 1020 Steel 1 040 00033 Backrest Shoulder Bar, 1/2" x 1/2" Tubing, 0.047 wall, 12" long 1020 Steel 1 050 50008 Hinge Spacer, 0.5" ID 1020 Steel 2 060 50009 1/4"‐20 x 2" Bolt w/ nut and washer Grade 8 2 070 00034 Roller Bars, 1" x 1/4" flat stock, 13" long 1020 steel 2

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6.2.) Operation Instructions and Maintenance

VERSATILE MECHANICS CREEPER OPERATION INSTRUCTIONS AND MAINTENANCE

SAFETY PRECAUTIONS:

OPERATION INSTRUCTIONS: ! Jack the vehicle up a minimum of two feet above the ground before attempting to work

underneath it. ! Carefully lay down on the creeper on a smooth and level surface. ! Roll under the vehicle with the creeper at its lowest setting to avoid head injury when rolling

underneath it. ! Adjust the creeper using a 9/16” wrench, socket, or screw gun, to the desired angle by

moving the nut in a counterclockwise direction. ! Before exiting from underneath the vehicle return the creeper to its lowest setting to avoid

injury by moving the nut clockwise. ! Roll out from underneath the vehicle. ! Carefully stand up off of the creeper.

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MAINTENANCE AND STORAGE: Storage: ! Be sure to store the creeper vertically to avoid accidents such as tripping over it or driving

over it with the vehicle. ! The creeper should be stored in a dry environment to keep the pad from becoming moldy. ! Always clean the creeper before storing it to ensure a longer life. Maintenance: ! Clean the creeper after every use. ! Make sure all gears and moving parts are properly lubricated. (Any multipurpose automotive

grease can be used.) ! Check the creeper for any loose bolts, and tighten as needed. ! Make sure the bearings in the casters are clean and well lubricated.

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7.) Conclusions

After consulting many professionals and hobbyists, we found a significant interest in our

product. The adjustable backrest in our design solves many issues that professionals and

hobbyists experience that include neck and lower back pain. The alleviation of these pains

prevents potential neck and back problems further down the road and increases work

productivity due to being more comfortable and relaxed while working. The adjustable backrest

also improves the safety of the user as they are no longer working directly under potential

hazards; instead you are now at eye level with the work which in turn prevents things from

entering the eyes and mouth. Our creeper is virtually maintenance free, only requiring the

occasional greasing. Our product is designed to be priced competitively with other creepers on

the market today while increasing its versatility many times over. We plan on making a number

of changes to improve the operation of the mechanism to make it easier to operate. In addition,

these changes will also reduce the overall weight of the creeper itself.

8.) References Machine Elements in Mechanical Design, 4th edition, Robert L. Mott Applied Strength of Materials, 5th edition, Robert L. Mott Machines & Mechanisms: Applied Kinematic Analysis, 3rd edition, David H. Myszka Machinery’s Handbook, 28th Edition 9.) Appendices 9.1.) Team Qualifications This mechanical design project seems to cater to the general experience our team has

acquired over our high school and college years. As our resumes indicate, we all have

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experience working with our hands on a variety of projects. Therefore, the thought of building a

prototype was an afterthought compared to the task of designing the creeper. We generally knew

that once our concept was mapped out, we could effectively build our prototype within a short

time period. The qualifications for each team member are as follows:

Mathew D. Hudon

! Coursework excellence in the areas of Machine Design and Strength of Materials.

! Prior manufacturing experience using vertical milling machines and lathes.

Christopher J. Llanes

! Coursework excellence in the areas of Kinematics and Machine Design.

! Creative thinker and mechanically inclined.

Andrew S. McDonough

! Proficient in mechanical know-how as well as knowledge of technology used in industry,

especially the automotive field.

! Good at developing design options to an existing design in order to produce the best

design possible.

Timothy J. Rachielles

! Very creative. Came up with the Versatile Mechanic’s Creeper idea.

! Mechanically inclined and has an extensive amount of experience working on mechanical

systems.

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9.2.) Resumes of Team Members Mathew D. Hudon 7 Gabriel Farm Dr., Acushnet, MA 02743 774-644-1408 [email protected] Education Wentworth Institute of Technology, Boston, MA Exp: August 2010 Bachelor of Science: Mechanical Engineering Technology G.P.A.: 3.48/4.0, Dean’s List – Summer 2009, Spring 2010 Old Colony R.V.T.H.S, Rochester, MA June 2006 Machine & Tool Technology Certifications

! Passed the April 2010 Fundamentals of Engineering Exam (EIT License pending for work experience) ! Certified Solidworks Associate ! National Institute for Metalworking Skills (NIMS) Certified Machinist

Technical Competencies Design: SolidWorks, AutoCAD, MasterCAM Information Technology: Microsoft Office Manufacturing Technology: CNC Mill & Lathe experience, MIG welding, surface grinding Experience Triton Systems, Inc., Chelmsford, MA January 2009-December 2009 Mechanical Engineering Co-op – Advanced Materials, Products, and Systems

! Contributed to the advancement of products and systems for Department of Defense (DoD) projects. ! Helped develop a solution to lower the overall manufacturing cost of smoke grenades. ! Manufactured Armor Repair Kits for ballistic protection against armor piercing bullets. The kits are to be tested and then

eventually used on High Mobility Multipurpose Wheeled Vehicles (HMMWV). ! Machined molds from graphite for Pressurized Infiltration Casting in a vacuum furnace. Aluminum Matrix Composite

technology was used to produce a new material that had good wear resistance and thermal properties. Polyneer, Inc., New Bedford, MA May 2008-August 2008 Mechanical Engineering Co-op – Rubber Injection Mold Design

! Designed a rubber part removing fixture that connects to the press in order to decrease physical labor. ! Took part in the rubber injection mold design process, primarily using AutoCAD. ! Repaired rubber molds that had been damaged during the molding process.

James L. Gallagher, Inc., Mattapoisett, MA June 2008-August 2008 Machinist

! Analyzed drawings from Solidworks software and machined parts from those drawings. CNC and manual machining techniques were used.

! Machining was done under the supervision of an experienced machinist, and a lot was learned from this experience. Acushnet Tool Co., Freetown, MA June 2004-August 2006 Machinist

! Manufactured rubber injection molds using CNC milling and lathe techniques, surface grinding, and welding. ! Experience gained in using MasterCAM software. ! Machined and heat treated parts for customers. ! Learned a lot about materials as machining was done on many different steels and aluminums.

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Christopher J. Llanes 40 Meadow Lane Apt. 12 �4'5#%26!7"(!#&'89':;<;= � (508) 577-7113 � [email protected]

EDUCATION: Wentworth Institute of Technology- Boston, MA Bachelor of Science, Mechanical Engineering Technology, August 2010 G.P.A 3.505/4.0, Deans List: Fall 2006-Spring 2010, Merit Scholarship recipient. COURSEWORK: Mechanical CAD Applications Manufacturing Processes Mechanical Graphics Statics Fluid Mechanics Calculus 1, 2, and 3 Thermodynamics Machine Design Physics 1, and 2 PROJECT EXPERIENCE: Mechanical CAD Applications Course-Wentworth Institute of Technology: -Re-designed air powered engine to double the power output. -Created CAD drawings on Solid Works of all components. -Used AutoCAD to determine placement of inlet and exhaust holes. Chase Coating and Laminating: -Expanded upon need for new web handling machine capabilities. -Created concept design of proposed machine using AutoCAD -Evaluated used equipment to recommend modifications to fit requirements. -Completed time studies to determine operating speed. -Used Microsoft Excel to create a spreadsheet to determine oven drying requirements for coating machine. TECHNICAL COMPETENCIES: Computer Software: Solid Works, AutoCAD, Microsoft Word, Excel, PowerPoint, Adobe. Engineering: Mechanical Design process, Stress-Strain analysis, welding, casting, machining, mechanical graphics. Equipment: Lathe, milling machine, drill press, CNC machinery, press brake. LAB EXPERIENCE: Manufacturing Processes: -Utilized drawings provided to fabricate components for an air powered engine. -Used fabricated parts to assemble the engine. -Tested engines using specified air pressure and measured the RPM.

WORK EXPERIENCE Chase Coating and Laminating-Randolph, MA September 2009-Present

Mechanical Engineer Co-Op ! Was a member of a design group with engineers from the company with the goal to design a new web

coating machine. ! Evaluated equipment that the company had purchased in order to offer suggestions for modifications to fit

concept design of new machine. ! Conducted time studies and compiled data in Microsoft Excel to analyze and offer suggestions to improve

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current process times ! Developed a new system for physical inventory counts which saves time and improves the accuracy of

count by eliminating as much human error as possible. Depuy Orthopedics, Inc.-Raynham, MA January 2009-May 2009 Manufacturing Engineer Co-Op

! Collected, compiled, and analyzed process times from existing system in order to offer recommendations to staff structure to improve productivity.

! Restructured multiple departments by organizing tools and needed equipment to provide a safer workplace and to reduce waste.

! Teamed with associates to promote and initiate a lean manufacturing movement. ! Assisted supervisor and other co-workers in various tasks, which improved teaming skills.

Prime Glazing Co.-West Bridgewater, MA June 2008-August 2008

Laborer ! Received shipments of glass and aluminum window frames from manufacturers. ! Removed old glass and window frames in order to replace them. ! Used caulking to weatherproof window frames and glass to prevent leaks.

Venture Tape Corp.-Rockland, MA May 2006-August 2006 Maintenance Engineer

! Contacted vendors to order all parts for maintenance department. ! Utilized Purchase Order Organizer Deluxe to create purchase order sheets. ! Developed a tracking system using Excel to track all orders. ! Reviewed CAD drawings of different web handling machinery ! Helped diagnose and fix problematic web handling machinery.

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Andrew McDonough 83 Brewster Road 6177971232 Medford MA, 021551641 [email protected]

Education Wentworth Institute of Technology, Boston, MA Bachelor of Science, Mechanical Engineering Technology May 2011 Coursework

Mechanical Graphics Manufacturing Processes Statics Mechanical CAD Applications Thermodynamics I Kinematics Computer Aided Manufacturing Fluid Mechanics Heat Transfer Instrumentation & Measurement Electronics & Electricity Nanotechnology Dynamics Strengths of Materials Material Science Instrumentation & Measurement Heat Transfer Intro to Nanotechnology

Lab Experience Manufacturing Processes -Fabricate an air driven motor using lathes and mills Mechanical Design -Devise and fabricate a ping pong ball launcher Mechanical CAD Applications -Model in Solid Works a double acting steam piston Technical Competencies

Engineering -Welding (Gas and Stick), Casting, Viscosimeter, Manometers Devices -Engine Lathe, Milling Machine, Gantry Mill, CNC Software -AutoCAD, Solid Works, CAM Works, Microsoft Word, Excel,

PowerPoint, FrontPage Project Experience

Manufacturing Processes Final Project -Fabricated, assembled, and operated an air driven piston and flywheel engine. Each piece was machined by hand and assembled to compete with other students’ motors in terms of highest RPM.

Mechanical CAD Applications

-Tasked with the redesign of the single acting piston used on the Manufacturing Processes air motor into a double acting piston using Solid Works. Our design was the presented to our fellow classmates.

Work Experience MIT Seagrant AUV Lab, Cambridge, MA January 2009-Present Assistant Research Engineer

-I assist in the design, fabrication, assembly, and maintenance of Autonomous Underwater Vehicles for various types of underwater research. I also assist in an education program called the Seaperch Institute which educates middle and high schoolers about marine engineering and underwater research.

Brigham and Women’s Hospital, Boston, MA July 2007-November 2008

File Clerk, Department of Cardiology -Filing of critical medical records for cardiac and cardiac transplant patients. Locating and delivering medical charts to the cardiology clinic.

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Staples, Medford, MA August 2004-December 2004 Electronics Sales Associate

-General sales of business machines (Printers, Faxes, Copiers, Computers, etc.), inventory, stocking, security of merchandise.

Honors, Awards, and Leadership -Vice President of the Society of Manufacturing Engineers, Wentworth Chapter October 2008-December 2008

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Timothy J. Rachielles 74 Hillside St. Apt. 3

Roxbury, MA 02120

(860) 729-0634

[email protected]

www.timrachielles.com

OBJECTIVE: To obtain a full time Engineering position where product development and business growth are important aspects.

EDUCATION: Wentworth Institute of Technology Boston, MA Bachelors of Science in Mechanical Engineering Technology, 2010 exp. GPA: 3.0/4.0

RELEVANT COURSES: Physics I and II, Mechanical Design, Mechanical Graphics, Statics, Strengths of Materials, Thermodynamics I and II, Heat Transfer,

Instrumentation and Measurements, Intro to Nanotechnology, Calculus I, II, and III, Differential Equations, Materials Science,

Dynamics, Electronics MECHANICAL/DESIGN: ! Full body-off restoration of a 1990 Jeep Wrangler.

! Designed a set of defroster vents for a Jeep Wrangler to redirect air flow for more effective cabin heating.

! Machined all components to build an air motor.

! Designed and built a ping pong ball launcher.

! Designing and building patentable reclining mechanic’s creeper

WORK EXPERIENCE: BioScale Inc. Cambridge, MA Spring 2009

Co-op

! Assembled BioScales Acoustic Membrane Microparticle Beta Units to be submitted for testing allowing for swift customer

feedback.

! Assisted in preparing assembly instructions to decrease the amount of time required to assemble a beta unit.

! Designed and built a dust shield for testing equipment keeping the machine protected and preventing variability in the results.

! Helped develop proper assembly technique for fluidic manifolds ensuring that leaks and particulates would not affect the data.

Henkel/Loctite Rocky Hill, CT Summer 2006-2008

Summer Intern

! Generated impact, tensile, and environmental aging data using Instron testers, aging equipment, and ultraviolet curing

equipment for new and developmental products allowing engineers to quickly get the product ready for the market.

! Assembled customer parts with various adhesives and tested to failure, and wrote engineering reports to present to customers.

! Developed testing parameters using ASTM standards, and performed the tests, and provided results for a new Ultraviolet

Cure Acrylic adhesive.

Other Work Experience

! Developed skills in consumer relations through various retail positions

ACHIEVEMENTS: ! Founding member of the WIT chapter of Phi Sigma Pi

! Eagle Scout Troop 23, Burlington, CT ! Global Youth Leadership Conference New York/Washington D.C.

mailto:[email protected]

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! 100 Mile Hike Philmont Scout Reservation, Cimarron , NM ! Listed in Who’s Who Among American High School Students

! Recipient of the National Federation of Independent Business’ Young Entrepreneur Scholarship

9.3.) Weekly Working Notes of the Group Meeting #1 – Monday, May 17th, 2010 Time: 3:20 pm – 5:20 pm Location: Beatty Library (upper level) Topic of Discussion: This meeting mainly focused on developing some ideas as to what type of mechanical design we might want to pursue. Design options that were presented are of the following:

! Automotive creeper w/ an adjustable backrest -backrest controlled pneumatically, mechanically, or hydraulically to increase human comfort and efficiency.

! Chimney turbine system -utilize the hot air from the fire in a chimney to power a turbine further up the chimney. -could be applied to a home chimney or a clothes dryer vent.

! Sink drainage power generation -drain water from home sink powers a fluid motor.

! Self car jacking system -when pulling a car over on the highway, this system could enable the driver to press a button and the car would jack itself up via a hydraulic system running off of the battery or off of the engine.

Topics for next meeting:

1.) Bring in more ideas/vote on idea.

Meeting #2 – Tuesday, May 18th, 2010

Time: 2:30 pm – 4:30 pm

Location: Beatty Library

Topic of Discussion:

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The team couldn’t think of any more design options. We then held a vote for what design we wanted to pursue. The choice was: Automotive creeper w/ an adjustable backrest. We then discussed why there is a need for a product like this (Needs Assessment). Reasons brought up were: 1.) current creepers on the market require you to lift your back and adjust a steel swing arm, 2.) human ergonomic comfort can be increased. No more need to strain your neck to wrench a bolt under the car, 3.) human work efficiency can be increased, 4.) could be of interest to mechanics, especially small garage owners, racecar garages. We also discussed cost and support. We didn’t see any reason that the manufacturing of this creeper should exceed $1000. We expect it to cost a lot less to build. We have access to a garage in New Bedford, MA for the construction of it, where there is a lathe, Bridgeport, and all 3 types of welding. Topics for next meeting: 1.) Develop a plan using Microsoft Project. 2.) Prepare the preproposal. Meeting #3 – Thursday, May 20th, 2010 Time: 2:30 pm – 4:30 pm Location: Beatty Library Topic of Discussion: We talked about how we will complete the pre-proposal. Tim will do the “Introduction”, Andrew will do the “Needs Assessment”, Chris will do “Predicted Results”, and I will take care of the Microsoft Project planning as well as the “Cost and Support” section. We also talked about different lifting mechanisms for the creeper’s backrest. We have many different ideas of how to build the creeper and the coming meetings will help us determine which idea works best. For next week: 1.) Complete the pre-proposal. 2.) Continue Needs Assessment and design options. 3.) Bring in some more ideas. Meeting #4 – Monday, May 24, 2010 Time: 2:15 pm – 4:15 pm Location: Beatty Library Topic of Discussion: In this meeting, we worked on the pre-proposal. We tried to figure out what we want to name this project. We talked about names such as “Versa-creep” and “Versatile Creeper”. We finally came up with “Versatile Mechanic’s Creeper.” Some minor design issues were discussed.

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Talk about design options / finish preproposal.

Meeting #5 – Tuesday, May 25, 2010

Time: 2:20 pm – 3:35 pm, 3:50 – 4:35 pm

Location: Beatty Library


We completed and signed the pre-proposal. Also, the electronic version was submitted. We think it might be a good idea to include locking casters as well as a maximum of 30 degrees for the backrest angle. Topics for next meeting: Discuss design options in case our pre-proposal isn’t accepted. Meeting #6 – Thursday, May 27, 2010 Time: 2:30 pm – 4:30 pm Location: Cafeteria Topic of Discussion: We delegated the work for the final proposal, assuming the pre-proposal gets accepted. Andrew will add some content to the needs assessment portion. Chris will complete the design options and specifications portion. A backup idea we thought of was a jackstand with a built-in piston, where the car can be jacked up, and then the jackstand can lock into place. Design specs for the creeper were established. For next week: Complete formal proposal / start sketches and drawings for creeper. Meeting #7 – Tuesday, June 1, 2010 Time: 2:30 pm – 4:30 pm Location: Library

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Topic of Discussion: We set up a timeframe for when the design and analysis of the creeper needs to be completed by. We figure that it should be complete by the end of June, and then we can start building the prototype. Design criteria and specs were established and discussed.


Continue to discuss design / formal proposal status

Meeting #8 – Thursday, June 3, 2010

Time: 2:30 pm – 6:30 pm

Location: Library


For the main frame of the creeper, a key issue that was discussed was trying to keep the weight down while keeping the integrity of the design intact. Many options were discussed and the design will be modeled in Solidworks and then analyzed for strength. A model of the scissorlift mechanism has been started and we are working to make sure that will fit into the frame properly as well as if it will be strong enough. We talked about methods to drive the scissorlift via a handcrank/driveshaft mechanism and where to install it in the frame. Also, our progress on the formal proposal was discussed. Topics for next meeting: Bring in design ideas and strength analysis results for frame. Work on formal proposal. Keep working on solid models. Meeting #9 – Monday, June 7, 2010 Time: 2:30 pm – 4:30 pm Location: Wentworth 208 Topic of Discussion: Today’s meeting was mainly focused on a design problem. How is the backrest going to attach to the frame? Also, can we get the backrest to lay flat? We drew a bunch of ideas on the board and we will put together a model on Solidworks. We thought of putting a notch in one of the main frame members in order for the

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backrest to lay flat. We figure ½” x ½” AISI 1020 steel tubing will work. After the back assembly is designed, we will analyze for strength. Topics for next meeting: Finish formal proposal / Finish powerpoint for thursday

Meeting #10 – Tuesday, June 8, 2010

Time: 2:30 pm – 4:30 pm

Location: Wentworth 208


Chris finished up the design specifications for the formal proposal and Andrew added some information to the needs assessment. We conducted a survey online regarding what people would like to have in a creeper. This will be included in the needs assessment. I worked on the design options section and Tim worked on the powerpoint presentation. Design ideas were also discussed regarding the backrest design. Topics for next meeting: Discuss solid model of backrest assembly / possibly conduct strength analysis. Meeting #11 – Thursday, June 10, 2010 Time: 4:30 pm – 6:30 pm Location: Beatty Library Topic of Discussion:

We are on track to meet our goal of designing and analyzing the creeper by the end of June. The main frame assembly is designed. We spent this meeting discussing how we will mount the scissor lift to the main frame. The goal is to have the backrest lay very close to flat when the scissor lift is completely retracted. Also, ideas were discussed regarding the drive mechanism to the scissor lift. Modeling and further development of our design will continue over the weekend and into next week. Topics for next meeting: Work on completing main frame and scissor lift assembly model / keep making design progress Meeting #12 – Monday, June 14, 2010

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Time: 2:30 pm – 4:30 pm Location: Beatty Library Topic of Discussion: We conducted a strength analysis on the latest design of the main frame of the creeper. It produced a maximum stress of 27,000 psi, which gives us a 1.9 safety factor. We are making modifications to the backrest assembly to accommodate the scissorlift mechanism, as well as the linkage components that will operate it. We started to focus our attention towards the mid semester report, as it is due Thursday. Topics for next meeting: Assemble, organize, and complete the mid-semester report / work on design


Time: 2:30 pm – 4:30 pm



The mid-semester report was close to being complete at the meeting and will be finished by wednesday night. The scissorlift design problem has been fixed and will soon be analyzed for strength. Our main design focus has now shifted towards the drive system. Potential design problems we will face is to create a system that has a low profile, will transfer the torque effectively, as well as keep the cost at a minimum. Topics for next meeting: Bring in ideas and solutions to complete the drive system. Meeting #14 – Thursday, June 17, 2010 Time: 2:30 pm – 4:30 pm Location: Wentworth 208 Topic of Discussion: A parts list was created so that we can start to order the build material for the creeper. The drive system and scissor lift are still the main concern, and all of our efforts will be towards finishing those designs so that we can start building. We are definitely on track to finish the design of the entire creeper within the next week. Topics for next meeting:

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Talk about drive system design and how it will adapt to the scissor lift. Meeting #15 – Monday, June 21, 2010 Time: 2:30 pm – 4:30 pm Location: Wentworth 208 Topic of Discussion: Today’s meeting consisted of finding the parts online that we will need to order. Andrew ordered the casters and the tubing and scissor lift component material has been ordered. Mat will order the materials for the drive system and Chris and Tim will work on getting some padding and vinyl. We all agreed that the drive system design will work with a few minor changes. Topics for next meeting: Keep developing the design and possibly start making assembly drawings.


Time: 2:30 pm – 4:30 pm



We discussed how the brass nut, that the threaded rod goes through for the scissor lift, will be connected to the cross-brace. The backrest is being modified on Solidworks to accommodate the scissor lift connection. We will possibly start building the creeper on Saturday. Topics for next meeting: Continue the design process Meeting #17 – Thursday, June 24, 2010 Time: 2:30 pm – 4:30 pm Location: Wentworth 208 Topic of Discussion: Today we addressed what needs to be done by next Thursday for the 2nd informal presentation. This includes bill of materials, decision matrix, and final design option in the presentation. The building of the creeper

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will start on Saturday so a drawing with dimensions of the main frame will need to be done. We are finishing up our models on Solidworks. We also talked about how to incorporate tolerances on our dimensions and what interfaces should have tight or loose fits. Topics for next meeting: Work on powerpoint presentation for Thursday/parts drawings Meeting #18 – Monday, June 28, 2010 Time: 2:30 pm – 4:30 pm Location: Wentworth 208 Topic of Discussion: Tim has volunteered to organize the powerpoint presentation for Thursday’s second informal presentation. Chris will submit the BOM for the scissor lift to him, Andrew will submit the BOM for the backrest assembly, and Mat will prepare the BOM for the main frame and drive system. We discussed the successful build of the main frame for our prototype. We will continue our build in the coming weeks. Topics for next meeting: Fully prepare the second presentation / discuss design issues


Time: 2:30 pm – 4:30 pm



We all worked on our bill of materials for the presentation. Creeper build dates have been set for Saturday, July 10 and Saturday, July 17. The powerpoint presentation for Thursday was assembled. The drive system and scissor lift still need some final design modifications but we are very close to a finished model. Topics for next meeting: Work on finalizing our model so that we can develop detail drawings. Meeting #20 – Thursday, July 1, 2010 Time: 4:30 pm – 6:30 pm

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Location: Library Topic of Discussion: After our 2nd informal presentation was complete, we shifted our attention towards the building of our creeper. Building will resume on July 10th as we will assemble the backrest, and hopefully start to build the drive system and scissor lift. Topics for next meeting: Assess status on the build / update final report? Meeting #21 – Monday, July 12, 2010 Time: 2:30 pm – 4:30 pm Location: Beatty Cafeteria Topic of Discussion: Today we discussed our progress on the building of the prototype. Most of the parts were manufactured over vacation and the main frame is completed. We are scheduled to continue our build on Saturday, July 17 and expect to finish it or come close to finishing it. A design issue involving how to join the brass ACME nut to the steel cross brace of the scissor lift was talked about. Part drawings will start to be made by the group. Topics for next meeting: Assess progress on design issue and update final report.

Meeting #22 – Tuesday, July 13, 2010

Time: 2:30 pm – 4:30 pm



The website needs to be updated and Tim has volunteered to take care of that. We talked about what kind of foam and material should be ordered for the part of the creeper where you lay. We will manufacture a 15/16”-16 internally threaded piece of steel to solve the ACME nut problem. We have decided to continue with making part drawings. We will meet on Saturday, July 17 to continue the build of the creeper. Topics for next meeting: Resolve any design issues before Saturday and prepare for saturday

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Meeting #23 – Thursday, July 15, 2010 Time: 2:30 pm – 4:30 pm Location: Wentworth 208 Topic of Discussion: We discussed how we will divide the work on Saturday. We plan to start at 9 am. We worked on detail and assembly drawings. Topics for next meeting: Assess status on build and work on final report Meeting #24 – Monday, July 19, 2010 Time: 2:30 pm – 4:30 pm Location: Wentworth 208 Topic of Discussion: On Saturday, we came across a critical design issue. As the scissor lift extends and lifts the backrest, it binds. We found that it bound because there is a solid connection between the scissor lift and the backrest where there should be a sliding connection. We are in the process of redesigning this issue. Topics for next meeting: Work on design issue, fix website

Meeting #25 – Tuesday, July 20, 2010

Time: 2:30 pm – 4:30 pm



Our website was modified in today’s meeting. More pictures were added giving a better look to the website. We have modified the scissor lift design and will order material as needed. We will finish the build this weekend and meanwhile we will work on part and assembly detail drawings. Topics for next meeting: Technical poster status? Meeting #26 – Thursday, July 22, 2010

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Time: 2:30 pm – 4:30 pm Location: Wentworth 208 Topic of Discussion: On Saturday, we intend to complete the creeper prototype. Our design changes to the scissorlift should eliminate any problems. In this meeting, we worked on the technical poster as well as updated the final report. Once the prototype is completed this weekend, our full attention will be on getting the presentation ready for August 2nd. Topics for next meeting: Assess prototype status / prepare presentation / continue working on final report and technical poster. Meeting #27 – Monday, July 26, 2010 Time: 2:30 pm – 4:30 pm Location: Room #409, Building 610 Huntington Ave. Topic of Discussion: The prototype has been transported from N.C. Hudon Crane & Rigging, Inc. to Wentworth. We just need to mount the seats to it and we will have a fully functional prototype. This will be part of our presentation on August 2nd. We have shifted our attention to preparing a presentation for next Monday as well as completing the technical poster and final report. Topics for next meeting: Work on part drawings / finish prototype Meeting #28 – Tuesday, July 27, 2010

Time: 2:30 pm – 4:30 pm

Location: Wentworth Projects Lab


Today’s meeting was strictly focused on mounting the seats to the creeper. The prototype is officially finished and ready to present on Monday. We assessed our status on the final report and started to throw around ideas regarding the powerpoint presentation for Monday. Topics for next meeting: Prepare poster, presentation, final report Meeting #29 – Thursday, July 29, 2010

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Time: 2:30 pm – 4:30 pm Location: Beatty Library Topic of Discussion: We finished up the technical poster and we all approved its layout. Then, we went to Staples and had it printed. Each group member was given sections of the final report to complete. We will meet Sunday to assemble the powerpoint presentation. Topics for next meeting: Assess our presentation and organize final report / DVD

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9.4.) Samples of Engineering Notebooks of Team Members Mathew D. Hudon

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Christopher J. Llanes

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Andrew S. McDonough

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Timothy J. Rachielles

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9.5.) Breakdown of Tasks Mathew D. Hudon

! Main frame design and analysis ! Technical report writing

Christopher J. Llanes ! Design and analysis of scissor lift mechanism ! Helping with technical reports

Andrew S. McDonough ! Design and analysis of backrest subassembly and drive system ! Helping with technical reports.

Timothy J. Rachielles ! Design and analysis of drive system and scissor lift mechanism ! Helping with technical reports.

9.6.) Group Schedule and Progress

Department of Electronics and Mechanical MECH690...

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