GB620582A - Improvements in and relating to apparatus for indicating time intervals - Google Patents

Abstract

620,582. Switching systems for consuming devices. TELEPHONE MANUFACTURING CO., Ltd., SMITH, S. J., and TERRY, R,. ST. G. Dec. 14, 1945, No. 33901. [Class 38 (iv)] [Also in Groups XXXVII and XXXVIII] In a time-control device for effecting a recurrent cycle of operations of variable duration, a shaft 23, coupled to a motor 10 through a variable - speed gear (see Group XXXVIII), has mounted thereon a pair of cams 27, 28 which control contacts 39 and 40, whereby the current source is switched to the load for predetermined portions of the variable cycle. In the initial position the bent-over tip of armature 33 rests in the slot 26a of cam 26. Flap 29, which as shown, covers the slot under the action of a spring, is displaced by the armature 33. The cycle is initiated by operating the push-button 35, whereupon relay 34 is energized so that the armature 33 is lifted from the slot, contacts 38 are closed, and motor 10 commences. The flap 29 is now forced against the stop 32, while the tip of the armature rides in an elevated position on the periphery of the cam 26 and so keeps contacts 38 closed. After a complete rotation the armature 33 pushes aside the flap and falls once more into the slot 26a, thereby opening contacts 38 and stopping the motor. The operations are performed by cams 27, 28, which control the switching of current to a load device (not shown). The circuit is opened and closed by the parallel contacts 39, 40, the cams being so arranged that contact 39 always operates before contact 40, whereby, as may be seen from the figure, a rapid switching action is always achieved. An additional pair of cams 47, 48 may be used to effect a further cycle of operations.