Senior Design Project

The goal of this project was to develop a concept for a reacher/grabber tool that would reduce stress on the extremities of users with limited hand mobility. The reacher/grabber is a tool that is used to aid the user in retrieving an item without having to bend over. This is particularly beneficial for those who might have limited mobility. The design of a grabber requires the user to squeeze a handle and lift the item with their hand. Current mechanical grabbers do not offer a solution for users who have weak hands and wrists, perhaps due to arthritis. The solution being proposed is an arm braced grabber that is operated with an electric motor, thus removing the need for strength in the hands and wrists that is required in existing grabbers. The electro-mechanical grabber fills a void in the market, while offering a solution to those who are physically impaired.

The mechanical pulley system is controlled by an Arduino, programmed by myself. The Arduino uses a DC gearmotor to provide tension to a wire, which runs down the length of the pole, and into the jaw mechanism. To provide sufficient power and response time, the torque and rotational speed of the motor were carefully considered.

The parts shown in blue are currently in the process of being printed using my own personal 3D printer.

The pulley system was designed to input up to ten pounds of force, which culminates in approximately 15 pounds of closing force. A low tension spring is used to return the jaws to their outermost position, without inhibiting the force applied by the gear motor. The pulley system redirects the wire in order to apply the force perpendicular to the jaw's movement.

The arm support is designed to redirect the stress induced on the user's wrist and hands, into the upper arm. The adjustment mechanism was constructed using leftover pieces from old crutches, and operates in the same manner. The recycling of materials significantly reduced costs, and allowed the mechanism to be adjusted to fit a range of arm lengths.

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