Mechanical Seven-Segment Display Clock

Abstract

Over the ages, many different styles of clocks have been designed, but the seven-segment digital display supplanted most because of its simplicity when using LEDs to illuminate each segment. This project explores how the seven-segment display could be realized in an entirely mechanical clock out of curiosity. This is a great platform to study mechanism design because of the complexity of the problem and the many potential solutions that could exist. To solve this problem, many different mechanisms were considered, but ultimately a barrel cam was chosen to drive linkages that controlled the segments of the clock display. Barrel cams have great versatility; for example, they are widely used in motorcycle gearboxes and controlling tool motion in manufacturing equipment. Through multiple iterations, a successful mechanism using a barrel cam was prototyped that easily cycled through the required numbers when rotated.