Week 6: (In-Lab) Further Construction and Planning

This week, our team took the constructed frame to the Drexel Machine Shop to address the issue of adjustable height on each of the legs. Initially when the wheels were fitted to each leg, there was only one hole to adjust the height of the walker. With careful measurement, the team decided it would be best if 4" of the legs were cut off, allowing there to be more options of height.

Figure 1: This figure displays one of our teammates cutting the excess piping on the front and back side legs. 

As seen in Figure 1, one of our teammates created a rivet in each leg to aid the movement of the handsaw as each leg was shortened. This would allow the decision of space between each hole to be made, prior to constructing in the Machine Shop.

After precise measurements, each hole was drilled 1" apart, allowing there to be four options of height for the proper use of the walker. The wheels that were previously disassembled from one of the out of lab activities were tested to make sure the pin could be easily adjusted between holes. In Figure 2, one teammate was marking out where the holes would be with a measuring tape, prior to drilling them.

Figure 2: One teammate marking holes for the pin of the wheels.

After each of the four holes were carefully drilled into the bottom of the legs, the two sets of wheels were fitted to see if the holes were big enough to hold the adjustable pin. As seen in Figure 3, the wheel pin is set to the tallest height option of the walker. The holes were drilled at a downward angle, allowing the pin to remain in place after being set to the proper height. 

Figure 3: This picture displays the four rivets that were made for the adjustable pin. 

Next, the set of wheels were modified using Gorilla Tape, around the piping of the wheel to prevent wobbling or slipping out of place. As shown in Figure 3, the wheel displayed is one of the back right wheels with the beginning stages of the attached braking system. This modification of using the black Gorilla Tape helped to thicken the thinner rod that slides into place of the legs. The stopper located on top of the wheel will be configured so that a braking line runs from the wheel to the brakes that will be attached to each arm rest. This stopper is attached to a spring that when pressed, drops the metal stopper onto the rubber coating of the wheel, allowing the walker to stop in motion. This system is the next step in the construction of the walker. 

As seen in Figure 4 below, this is the initial structure of the walker that was completed with the help of the Machine Shop workspace. The multi direction wheels have been attached, allowing the front wheels to freely move in place. The back wheels, however, will be able to move as soon as the braking system is attached to the springs of the stopper. 

Figure 4: This picture displays the beginning stages of construction of the walker. 

The next plan for this design includes the finer details that will allow the walker to remain sturdy and withstand the designated tests to ensure results of proper posture. These tests, among others, will include the coefficient of friction and the range of movement the individual has when using the walker. The black back rest hanging freely on the back of the walker will be moved to a position that would be comfortable and supportive for any user. The other pieces of padding will also be added as soon as the walker withstands the team's expectations of providing proper posture and movement to an elderly individual. 

Week 5: (In-Lab) Designing Phase

When initially designing the side frames of the walker, our team was going to use Aluminum pipes and rivet the pieces together. However, after going to the Drexel Machine Shop, we were advised it would be best to use Steel piping and weld the pieces together instead. Although we were unable to work on the physical construction of the frame, we were able to further design the minor details of the walker.

Next, we discussed the finer details of the walker, including the braking system and the wheels that would be attached to the legs. Essentially we decided we would use a brake line, as seen in Figure 1, from a disassembled bike that when pulled, would press the stopper against the wheel and allowing the walker to stop moving forward. The design of the wheel was originally supposed to be built with a thick plastic caster and spherical wheel, but it was decided to use wheels that were previously assembled. Then, the stopper was designed so that when it will be attached to braking line system, a metal stopper will press against the rubber wheel, with the use of a small spring.

Figure 1: This displays an example of the braking like we would like to disassemble from an old bike. <http://www.aliexpress.com/bike-brake-set_price.html>

After the realization of having to add the sensor for proper placement, our team decided it was best to not include this because it would be quite bulky when connected to the side arms. The trouble of compacting the walker was already a difficulty so adding this feature would have significantly impacted the minor goal of easy storage.

This In-Lab meeting helped the team to discuss finer details of the walker prior to construction. Although we were unable to begin building the basic frame, the brainstorming helped the team to see future goals that we would like to achieve in the few weeks ahead of us.

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.