Golf Prosthesis Final Design Report (P12)
Jim Taylor made his final appearance on November 18th, 2011. Jim drove from Longview, WA to San Luis Obispo, CA in order to help us complete our senior project. At this point in the design process we were able to create two working final designs, the golf sleeve and golf cuffs. After testing both designs Jim provided us with numerous recommendations for the future ranging from functionality to material selection.
The main concern for Jim when he was swinging a golf club with our designs was holding on to the club for the duration of the swing. With Jim’s current device the grip of a club is actually connected to his left prosthetic arm via a clamp. This acts as a safety net so the club doesn’t fly out of his grasp. While testing both of our final designs it was difficult for Jim to hold on to the club the entire time. This limitation is due to the fact that when Jim swings, his shoulders extend away from his body, forcing his hooks to open up. With no other channel for Jim to be attached to the golf club it was easy for Jim to lose control of the club. Not only is this detrimental for completing a golf swing, it could also develop into a hazard for the user and others in the surrounding area.
The next suggestion Jim had for us concerned the grip angle. With his current design, the golf club becomes an extension of his left arm as seen below in Figure 32.
Normally a golfer would have a hinge in their wrists while addressing a golf club as seen in Figure 33.
Jim has no such angle change from his prosthetic arms to the golf club. This was an oversight in our final designs. We assumed the wrist hinge would still be in effect so we adjusted our designs to provide a slight hinge when addressing a club. Because of this flaw Jim wasn’t able to grip the club comfortably. The angle which he needed to address the club was so severe he was forced to contort his upper body, causing discomfort. In the future Jim would like to see us correct our designs in this area. As a note of caution, we are unaware if this is an issue for all bilateral amputees or if it is a single instance for Jim. Jim has a custom set of “golf arms” that are designed just for him. In our designs, we were attempting to simulate the natural angle of a person’s wrists while addressing a golf club. In the future, more research should be done on more bilateral amputees to confirm this notion.
Another suggestion Jim had for us was the position of his hooks while attached to a device. With Jim’s current device he is able to overlap his hooks so they’re resting at the same location on the grip of the club. This set up is shown in Figure 34. With our final designs we have the user attaching their hooks onto the device with the left hand slightly higher on the club than the right hand. This was done to simulate the natural grip of a golf club where one hand rests below another. What we overlooked was that because of Jim’s hooks he can actually grip the club in a single location by overlapping his hooks. By doing this Jim alleviates some discomfort by keeping his shoulders in a plane parallel to the ground. He doesn’t have to extend one arm further from his body than the other. This specification should be taken into account for future iterations.
The final major recommendation involves material selection for the final design. In our initial attempts to manufacture our products we created silicon molds to inject mold our design. If done correctly, this allows the maker to mold several parts out of different materials. We had hoped to use polyurethane as a final material but were unable to render a working silicon mold. This forced us to use the UV Resin rapid prototyper instead. In the future more research can take place to look at varying manufacturing processes. A suggestion would be to involve an Industrial Manufacturing Engineering (IME) major in the design process. Their insights would prove useful for not only manufacturing a final design but selecting a proper material that is flexible and durable.
Other recommendations for the future involve further customer research. First and foremost, more bilateral amputees should be contacted. Their insight and experience has proved invaluable for us in our design process. The more information gathered from more sources the better the final design will be. Also, we believe our devices can be used in other fields for bilateral amputees. The concept of a universal sleeve where amputees only need to use their hooks to attach onto an object can be further developed. Some rough ideas we had involved kitchen/house appliances. With a sleeve similar to our final designs, amputees could experience more independent freedom.