Three ball rotating pendulum display for clock - has spring-loaded spiked wheel driven by second shaft and providing torsion drive impulse to pendulum

摘要

The pendulum is hung by a torsion wire or tape from a fitting which is elastic on account of a spring permitting natural adjustment in the vertical direction. The pendulum is restrained from over-rotation by an attached projection stopped by striking a fixed pin. The three ball pendulum has a fixed natural frequency of about eleven seconds but is caused to oscillate at a frequency of ten seconds by means of an intermittent force applied by six spokes (25a) of a wheel (25) driven by the second shaft (27) of the clock. This wheel is driven via a coiled spring which ensures a smooth application of just sufficient torsion to turn the pendulum at this frequency.