
Revolution counter, inscribed with numbers
- Made:
- 1862 in Manchester
- maker:
- Richard Roberts

Revolution Counter by engineer Richard Roberts, 1862
This counter indicates by the use of two concentric revolving dials geared together by an epicyclic train. The dials are on a central fixed stud, which also carries a double-ended pointer. The larger dial has a toothed edge and is driven by a worm from the shaft whose revolutions are to be counted; the ratio of the gearing is 1 : 100, so the dial counts up to 100 rev. The dial carries at the back a pin, upon which runs a long pinion gearing into a spur wheel of thirty-nine teeth fixed to the stud, and also into a wheel of forty teeth secured to the back of the inner dial. By this means the inner dial, which reads up to 4,000, is rotated at 1-40th of the speed of the outer one.