GB468235A - Devices for momentarily interrupting electric circuits - Google Patents

Abstract

468,235. Momentary - contact and electromagnetic switches. CRABTREE & CO., Ltd., J. A. (Schiele & Bruchsaler Industriewerke Akt.-Ges.) Jan. 3, 1936, No. 233. [Class 38 (v)] A device for effecting momentary interruptions in supply station circuits comprises a switch which is adapted to be moved into and held in the " on " position by suitable forces and on impact, ballistic or inertia arrangement under the control of an operating member which comprises a reciprocating or rectilinearlymoving plunger which is so projected against the movable contact of the switch as to cause the forces holding the said contact in the " on " position to be overcome momentarily. As shown in Fig. 1, on energization of an electromagnet 3 a core 4 rises rapidly and owing to its inertia passes rapidly through the point of maximum attraction and engages a bridging contact bar 2 at the upper part of its initial movement. The bridging member is thus momentarily raised against a spring 1 from its co-operating contacts 2a, 2b and after this short interruption the core returns towards its central position in the solenoid while the bar is again moved by the spring 1 to its bridging position. Thus an extremely short interruption of the controlled circuit is produced which is of a duration of the order of one cycle of an A.C. supply. In alternative modifications described, an auxiliary weight may be inter. posed between the core and the contact bridging bar and the latter may be fitted with main and auxiliary contacts which are sequentially operated. In a further modification shown in Fig. 3, the electromagnetic operation is dispensed with, the impact member consisting of a weight 4 in a cylinder 8 which is normally held by toggle mechanism in the position shown in which an upper spring 3a is tensioned and a lower spring 3b compressed. When the toggle mechanism is released by operation of a tripping push-button 9b, the weight is released and rises rapidly under spring action. The bar 2 is then momentarily raised by an auxiliary weight 7 normally resting on a fixed plate 6 but momentarily impelled in an upward direction by the casing 8.