GB233411A - Improvements in or relating to electric switches - Google Patents

Abstract

233,411. Cox, F. B. Feb. 6, 1924. Automatic circuit-breakers have a pivoted contact arm held by a detent in the closed position, a pivoted striker-bar being provided which is controlled by the no-volt or overload device and is adapted when released to strike the switch-retaining detent, the striker-bar being returned to its operative position by the joint action of the angularly-moving switch part and flexible means between this part and the striker-bar. As shown in Fig. 1, the pivoted contact blade A is provided with a retractive spring C and is connected by a spring e<2> to a coaxially pivoted striker-bar E controlled by the novolt electromagnet N. When the switch is closed (Fig. 3.) a pin d' on the switch blade A is engaged by a spring-controlled hooked catch D. During the closing operation the line of action of the spring e<2> is brought across the pivot e<1> but the bar D is held up by the electromagnet N, the circuit of which is completed before the deadcentre position is reached. On failure of voltage the bar E is released and moved downward bv the spring e<2> to strike the tail d' of the detent D and so release the switch arm A, which is moved to the off position by the spring C. During this opening movement the spring e<2> is again brought across the line of centres (Fig. 5) so that the striker-bar is automatically returned to the position shown in Fig. 1 in which it is controllable by the electromagnet N. A modification of this arrangement for overload release is shown in Figs. 6 and 7, in which the spring e<2> is not brought across the dead-centre position during the closing of the switch but is moved ,across by the plunger o<1> of the overload coil O. In further modifications also described, the striker-bar may be pivoted to an arm extending from the pivoted switch member, a spring connecting a point on the striker-bar with the pivot of the contact arm or an arm on the contact member may engage a yielding member such as a plate spring connected to the striker-bar which is pivoted on an axis removed from that of the contact arm. Specification 208,731 is referred to.