Reducing The Houston Flexible Wrist To Practice

In another paper Rosa Jacobs will describe the Houston Flexible Wrist and its successful use on a nurnber of children and adults. Reported here is the method followed for generating a production version of this wrist and the several products that are now available. Figure 1 shows a cross sectional view of a typical wrist fit to a user in the Houston trials. The ball element is more accurately desaibed as a knob since there was no attempt to achieve true ball and socket fit. Rather contact between the knob and the edge of the hole in the lamination element tended toward a line contact Both elements were aluminum and the contact generated considerable wear and friction. The most important element in the wrist after the ball and socket is the cornpression pad assembly. As the hand moves with respect to the forearm, the pads are both compressed and stretched, There is a considerable absorption of energy since they are made of Poron foam; however, they do bring the wrist back to neutral whenever a deflecting torque is removed Though not shown in the drawing the glove worn with the typical hand is also part of the system tending to straighten the wrist back to neutral when it is bent.