By P Hitchin

This clock is powered by 25 stainless steel balls.

The Ferris wheel holds eight balls at anyone time which drives the train. The wheel rotates once every four hours, and one ball drops off every 15 minutes. The ball drops onto a pair of contacts energizing an electric motor; an Archimedean screw which makes a single revolution lifting the ball 15mm  (the diameter of the ball) and in the process a ball is ejected from the top of the stack and rolls on to the Ferris wheel. When a ball drops off it rings a small bell.

The Ferris wheel carries two 1OO tooth wheels, one on either side. These wheels engage 25 tooth pinion wheels attached to the centre arbor, which is split Into two parts. The rear wheel and pinion drive the time train and pendulum, while the front wheel and pinion drive the motion work and hands.

The escapement wheel is made from titanium, and the pallet nibs are made from tungsten carbide. All pivots are made from high-speed drill steel running in aluminium bronze bushes with high-speed drill steel end caps. The Ferris wheel arbor runs in precision ball races.

The clock is powered by four AA rechargeable batteries which last approx two months. The base is made from Indian Laurel which accommodates the electronics; a 12volt geared motor running on 6volts, and batteries.

This fascinating clock was built to a Dick Stephen design and exhibited by P Hitchen at a National Model Engineering and Modelling Exhibition.  



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