Paul Horton suffered a quadriplegic spinal injury that limits mobility in his hands. This means that he cannot perform some actions such as clenching his fist tightly and also has very little strength in his thumb. Additionally, he cannot use tools such as pliers or scissors. Also, actions that requires gripping strength like, for example, using a steak knife or changing an adjustable screwdriver head are close to impossible. With this problem in mind, the team set a goal to create a set of pliers that is easy to use, lightweight, and mobile for his daily use.
From the criteria set above, the team made the decision to create an automated set of pliers powered by 8 AA batteries. The motor the team used is designed to be powered from a 12 volt power source, which 8 AA batteries provides. Additionally, Paul has expressed that he has and regularly uses rechargeable AA batteries, easing the decision making process.
Coupling together the motor shaft to a lead screw, the rotational motion of the motor is transferred to linear motion using a nut. This nut is attached to a bracket that connects to two linkages with bearings allowing for free rotation. Lastly, two plier heads are grounded fixed together at a point, forcing them to undergo pure rotational motion depending on the position of the linkages.
