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The Motorized Book Rest

THE PROBLEM:  The client has a very limited vertical field of sharp vision, very limited range of motion of his head, and restricted arm motion and arm strength. He wants to be able to read books, and has to use a book rest as he is unable to hold a book for more than a few minutes. But his off-the-shelf book rest holds a book at one height only. This enables him to read only few lines of print clearly. He requested something to raise and lower his books so that he can read complete pages.

THE SOLUTION:  The solution was a motorized book rest that is driven by an available 6 Volt battery-operated two-speed reversible electric drill/screwdriver. The casing of the drill was opened and cut in half to separate the handle (complete with battery and switch) from the motor. The handle rests in a cradle made of MDF at the front of the book rest. The motor is mounted to the back of the main plate, and it turns a threaded rod that drives a carrier up and down a slot in the main plate. The carrier drags the book carriage up and down. The MDF main plate is hinge connected to MDF base rails, and its angle is set using overlapping aluminum strips and screws. The book carriage has a stained and varnished oak ledge (client request) with holes in it sized to fit pencils - these are used to keep pages open. The back of the book carriage is clear acrylic per client request. The maximum torque of the drill/screwdriver is set at the lowest point (2 ft-lb) which provides more that enough power to raise a thick telephone directory. Locked nuts on the threaded rod provide travel end stops, and the noise of the torque mechanism indicates that the limit has been reached. The client selects the up/down direction using the forward/reverse selector switch of the drill, and operates the on/off trigger using a pencil as a lever. Later modifications: 1. The pencil used as a lever on the trigger has been replaced by a 1/4 inch eye bolt as pencils broke too frequently. Slop has been reduced with locknuts. 2. The client found the small UP switch difficult to push. A large flat paddle has been put in front of the switch, which the client finds much easier to operate. He has no problem operating the small DOWN switch. 3. The drill handle (complete with battery and switch) was jammed into the the MDF cradle with pieces of wheelbarrow tire to prevent any movement. The switches now operate with the precision of a new BMW gearbox instead of with the slop of an old Austin 7 gearstick

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