GB564029A - Improvements in or relating to revolution and like counters - Google Patents

Abstract

564,029. Stop watches. VICKERS. ARMSTRONGS, Ltd., and WILKINS, H. C. Dec. 2, 1942, No. 17161. [Class 139] [Also in Group XIX] A revolution counter is associated with means for indicating the periods of time over which the revolutions are counted, the counter being connected and disconnected by an electricallyenergized device, the switch controlling this device being arranged to control also the starting and stopping of the time-indicating means. Movement of a hand lever 21, Fig. 3, into the " start " position slides a cam bar 23 to start a stop watch 27 and also closes contacts in the circuit of the winding 10, Fig, 1, of an electromagnetic clutch 15. An armature 8 is thus slid along a square part of a shaft 4 to couple the shaft to a hub 3 connected by worm gearing 2 to the shaft 1 under test. The shaft 4 drives a pointer 5 and drums 18 indicating number of revolutions. Movement of the hand lever 21 to the " stop " position slides the cam bar 23 to stop the watch 27, breaks the circuit of the winding 10 and closes the circuit of an opposing winding 11. This causes the armature 8 to slide to the left to declutch the shaft 4 from the driven hub 3 and, by reason of the contact between the armature 8 and a fixed part 12 to hold the shaft 4 against rotation. The revolutions indicator 5, 18 may be zeroized manually when the circuits of both windings 10, 11 have been broken by a switch 17. The stop watch is mounted in a spring support 28 adjusted by a screw 29 and is reset by a manually-operated lever 26.