Week 5: (Outside-Lab) Primary Construction

The majority of the construction of the walker was done during free time out of class this week.  The first important task that needed to be done was to take the pipes to the machine shop in order to cut and sand them.  This was done using a table saw and sanding belt by team members, as seen in Figure 1.  The pipes were then welded by Mark, the machine shop advisor after the pipes were carefully laid out in the proper orientation.  The frame was designed in three major pieces, two sides with 4 legs total, and a square back panel.  These pieces were then held together with four door hinges as support.  Door hinges were used because they provide the flexibility needed to allow the legs to fold inward, while also being strong enough to hold weight.

Figure 1: Figure 1 displays the welding and construction of the walker's frame. 

The second major task was to use a previously-owned "rollator" walker to salvage wheels and brake levers. Two stationary wheels, which would be used in the back legs of the walker, and two swiveling wheels, which would be used in the angled front legs of the walker to provide mobility.  The team saw an opportunity to act on one of Dr. Seliktar's proposed ideas and use the existing brake to create a braking system that was always locked unless a lever was pulled.  However, the existing brake was fashioned in a way that it only locked when the brake lever was applied.  The initial braking system is shown in Figure 2 below.

Figure 2: This picture shows the initial brake system, which was unlocked unless the brake lever was applied.

While this setup did not fit the team's design plans, the parts were usable to create a new braking system.  By sawing off the initial braking bar, and using an angled bracket to create a new braking bar on the same side as the brake wire, the team created a brake that was normally locked unless the brake lever was applied, which is shown in Figure 3 below.



Figure 3: This figure shows the redesigned braking system, which is locked unless the brake lever was applied.

After the frame construction and brake redesign, the walker's wheels were attached to thinner pipes, using rivets and welding, which can be inserted inside the legs to make adjustable height.  Holes were drilled into the legs and thinner pipes, and a spring clip was inserted in the thin pipes to allow sliding.