GB747052A - Improvements in or relating to devices for indicating the condition of rest or movement of a rotatable shaft - Google Patents

Abstract

747,052. Cam-operated switches. EDEL. BLUT, J. March 10, 1954 [March 10, 1953; June 27, 1953], No. 6972/54. Class 38(5) [Also in Group XIX] A device for indicating the condition of rest or movement of a rotatable shaft comprises two-spring-loaded tappets actuated alternately by a cam device driven by the shaft for operating electrical contacts controlling an indicator provided with an intermittent contact device, the arrangement being such that when the shaft is at rest the indicator gives an intermittent indication whilst when the shaft is rotating the intermittent contact device is rendered inoperative. In one embodiment, Fig. 1, the shaft 2 is connected by a one-way coupling to a cam 3 which alternately pushes tappets 4, 4a outwardly of the casing 1 to close switches 7, 7a connected across an intermittent contact device 11 in circuit with a hand switch 13, a battery 15 and a lamp 18. The tappets move in extensions 1a of the casing 1 against springs 6 and pistons 5 delay their return movements. When the shaft 2 rotates counter-clockwise the cam 3 closes the switches 7, 7a in turn and the delay provided by the pistons 5 is such that the switches 7, 7a remain closed to short-circuit the intermittent contact device 11. The lamp 18 is therefore constantly lit. When the shaft 2 stops or rotates clockwise one or both of the switches 7, 7a will open and the intermittent contact device 11 will control the lamp 18. In a modification (Fig. 2, not shown) the tappets are replaced by spring- pressed pivoted levers each of which control pairs of contacts and the return movement of each lever is delayed by a diaphragm and associated spring-controlled non-return valve.