Week 4: (In-Lab) Dimensions and Brakes

Today, our team discussed the physical dimensions of the walker to begin building the aluminum structure of the frame. As seen in Figure 1, a rough sketch was drawn with the determined measurements according to the estimated height of an elderly individual. The "x2" written on the right hand side of the picture indicates the dimensions applying to both sides of the walker.

Figure 1: This displays the determined dimensions of the walker. This will be applied twice, for both sides of the walker. 

After considering these dimensions, the initial idea of using a brake system with a gripping mechanism to stop the wheels from moving forward, another approach was decided. With the discussion contributed from Dr. Seliktar, the idea of using a bicycle seat and pressure obtained from sitting could potentially lock the wheels. In this sense, an individual who has difficulty applying pressure or gripping their hands tight could stop the walker easily.

Aside from the physical building process, a few tests were determined and discussed in terms of actually testing this design for an individual. Some of which will be sketched out to determine the force applied to make the walker stop as well as from tipping when going down an incline. These tests include:

• the angle of the back: range of the angle allowed and what would be typical (referenced to someone standing up)
• getting up from a seated position: applying a set amount of weight to show it won't topple over
• find coefficient of friction: make an argument of why it is sufficient, why it is stable
• maximum weight it can hold on the bicycle seat (force applied)
• maximum angle that would cause walker to tip over: measure in different positions