MS5210 – Product Design & Business Models

(Module 3 - Prototype)

Submitted by,

Ravi Teja G – ME08B021

Chandrasekhar G – ME08B022

Abhinay S – ME08B058

Laxmi Narayana B – ME08B014

Problem Statement:

Design a product which can easily carry water cylinders over stairs

Our Approach:

Firstly, we had a team meeting and sorted out the following criteria (The TRIZ techniques taught in module 2 were quite helpful here!) –

What is the problem? - Water cylinders are heavy

Why is it a problem? – It is tough to carry them

Where is it a problem? – When carrying them over the stairs

So, we had to design something that has some room in which a cylinder can be placed; it had to have some equipment for easy movement on stairs. That would essentially solve our problem.

Arranging the room is not something that one should think of since it is not a big issue. So, sorting out the design criteria in this manner made us think of what exactly is the prime most requirement in our product – and we narrowed it down to the “stair-climbing device”.

First thing that came to our mind was “wheel” – cliché. Arranging two wheels on either side of a frame does reduce our effort compared to lifting with hand, but it is as bad as riding a bicycle on the stairs. So, we needed a more efficient technique to serve the purpose.

After a great amount of googling, we found out something called “tri-wheel mechanism”.

(image source: Wikipedia)

As shown in the figure above, it consists of three wheels each 1200 apart. The whole assembly can rotate about an axis passing through its centre and also, each wheel can freely rotate on its own central axis.

Whenever there is an obstruction (stair in our case) in its path, the first wheel that touches the obstacle stops and the whole assembly rotates till the next wheel touches the upper face of the stair.

Then the assembly rotates again such that the whole equipment gets on to the top of the stair. The force required in this process is very less compared to a single wheel.

With this in mind, we modeled a product in 3d studio Max as shown below -

It has an adjustable belt strap for holding various range of diameters. I provided a cushion material at the point where the person using this, places his/her hand.

We then proceeded to make a prototype!

Prototype:

We used 6 wheels from the robotics team of our institute and made 2 sets of tri-wheels. We made the frame using PVC pipes and the base with wood.

Dimensions of prototype are shown in the below figures –

(Considering step dimensions as height: 12cm, width: 28cm)

ProE model:

We developed a model in Pro Engineer, keeping in mind the original dimensions of the product.

Here are the results –

(Considering step dimensions in the hostels - height: 17cm, width: 39cm)

Top view –

Side view – Front view -

*Note: all dimensions are in cm

Customers:

People who carry heavy objects over stairs in buildings/hostels without elevator

Advantages:

• Easy to use (It can be easily climbs up steps or Kerbs)

• Reduced human effort (pulling trolley is easier than carrying objects on one’s hand/shoulder)

• We can carry wide range of objects by adding extra attachments like a bag which can carry vegetables, milk packets etc.

• Time for carrying things is minimized

• Low cost, durable

• Easy to fix the spare parts like wheels

• As only wheels are in contact with the ground while climbing, no damage is done to the steps/floor.

Disadvantages:

• The product we made can carry only one heavy object (gas cylinder/water can) at a time.

• Stair climber wheels can sometimes be problematic when trying to turn on flat ground as four wheels in a fixed position will be in contact with the ground at all times unless a locking mechanism is built into the trolley.

Cost of materials used for prototype:

Object Quantity Dimensions (cm) Cost (Rs.)PVC pipe

(OD:2cm,ID:1.9cm)1 135 10.00

L and T joints 2,2 - 10.00Wooden board 1 27*22 20.00

wheels 6 Dia: 6.8 180.00Aluminum frames 14 11.2*1.3 100.00

Nuts and Bolts 6 4*0.4 10.00Nuts and Bolts 8 3*0.3 10.00

Iron rod 1 28*0.6 25.00total 365.00

Estimated cost of the product:

Object Quantity Dimensions (cm) Cost (Rs.)Steel pipe

(OD:2cm,ID:1.9cm)1 200 130.00

L and T joints 2,2 - 25.00Wooden board 1 38*32 50.00

wheels 6 Dia: 9 240.00Tri star Aluminum

frames2 8.26*2 100.00

Nuts and Bolts 6 4*0.4 10.00Nuts and Bolts 8 3*0.3 10.00

Iron rod 1 38*0.8 50.00total 615.00

Conclusion:

Thus, we have identified a problem, developed a product to solve that problem, designed a model in ProEngineer, created a prototype and estimated the cost of the product.