Golf Prosthesis Final Design Report (P6)
The wrist hinge in a golf swing is a crucial element that adds club head speed as well as the necessary downward striking force needed to create optimal contact with the golf ball. The slotted wrist idea originated from this very need, which is apparent for double arm amputee golfers who lack rotation and the ability to flex their wrists. Our first attempt at this design is show in Figures 15, 16, and 17.
The design attaches to a golf club by attaching the terminal devices on at the head of the golf shaft, towards the head of the club, and then sliding the slotted wrist and TRS terminal device up the golf shaft towards the grip. The slotted wrist is then secured in place by friction.
The design in its entirety is composed of two key components. The left arm utilizes the TRS grip (background fig. 17), and is made from a polyurethane material. The right arm will utilize the Slotted Wrist design, and will apply a hinging force to the left terminal device during the golf swing as the user contracts their right bicep. The Slotted Wrist will be made from an aluminum alloy or composite material for high strength and light weight.
The slotted wrist uses a unique angled slot design, where the golf shaft is allowed to pivot within the cavity of the slot (Fig. 17). This design allows the user to apply a vertical force to their left wrist, storing energy in the Eagle TRS terminal device, simply by contracting their right bicep. This allows the user to hinge the golf club into the proper position on the backswing. During the down swing, the energy stored in the elastic material of the Eagle TRS grip will be released as the right bicep extends, unhinging the left wrist and returning some of the stored energy back into the ball at impact. A 3-D model of this design is located in Appendix D.
After meeting with John Lawson and speaking with Jim Taylor over the phone, we realized that our initial idea was unacceptable. Our initial idea for the Slotted Wrist would force the user to remove both hooks from their prosthetic arms, rendering them almost completely helpless to perform other necessary tasks outside of swinging a golf club. We needed to find a way to incorporate at least one hook, preferably their dominate hook, into our design. To overcome this challenge we added a wrist attachment and a quick release lever to our Slotted Wrist design. Now the golf prosthetic could be secured to their prosthetic arm without the need to remove their dominate hook. The addition of the quick release allows the Slotted Wrist to be pivoted into and out of position. In this way, the Slotted Wrist can be used during the golf swing and then repositioned afterwards so that the prosthetic device is no longer in the way, allowing the user to freely use their hook. Initial sketches of their design improvements are show below in figures 18 and 19.