GB1309847A - Mechanically actuated electric switches - Google Patents

Abstract

1309847 Mechanical switches; automatic circuit breakers; contacts HONEYWELL Ltd 17 Nov 1971 [20 Nov 1970] 55159/70 Heading H1N In an electric switch, a contact carrier 10, Figs. 3, 4, is pivotally mounted on an actuating member 11 by which it is moved transversely of its axis and in resilient sliding contact with a surface 14, at least one abutment 15 being provided on the surface 14 to catch the edge of the carrier 10 and cause it to rotate. In the example of Figs. 3, 4 the moving contact 12 is U-shaped with its arms recessed in the carrier 10 and two abutments 15, 16 are provided on a fixed contact 14 along which the carrier 10 is caused to slide by an actuator 11 having a retractive spring (not shown). On depression to close the switch, the carrier 10 engages the abutment 15 as shown in Fig. 3 whereby it is tilted to raise a second fixed contact leaf spring 13 which operates to snap the carrier 10 over-centre so that the contact 12 snaps to bridging engagement with the fixed contacts 13, 14 and then continues to slide. On release the carrier 10 overrides the abutment 15 and is tilted by the abutment 16 whereby the non-conducting faces of the carrier 10 engage between the free ends of the contacts 13, 14. In a modification, Figs. 6-10 (not shown), only one abutment, as 15 is provided so that the switch is of the push-push type and on retraction overrides the abutment 15 to leave the contact 12 in bridging engagement. On the next depression, the carrier 10 is again rotated to leave the carrier 10 with its non-conducting faces in engagement with the contacts 13, 14. In a further example, a contact carrier 50, Fig. 14, is mounted on a lever actuator 51 and is resiliently held in a central recess 58 of a fixed contact carrier 56 by a compression coil spring 52. Movement of the lever 51, in either direction, causes the carrier 50 to engage edges of the surface 57 of the fixed contact carrier 56 whereby the carrier 50 snaps over to either of the hatched position (shown) where contact inserts 53 or 54 bridge fixed contacts 59 or 57 with a further contact (61), Fig. 6 (not shown). In a modification, Fig. 13 (not shown), the bridging inserts 53, 54 may be replaced by contact carrying spring arms (43) engaging fixed contacts (47), (48) remotely mounted from a central member (44) having a recess (45) and surface (46) on which the carrier (40) tilts and slides. Automatic circuit breakers.-In a further example, a movable bridging contact 22, Fig. 11, on a pivoted carrier 20a is normally held by a latch 25 in a position A to bridge fixed contacts 23, 24 but is releasable by overload current resulting in a bimetal strip 27 operating to depress and release the latch 25. The actuator 21 is thereupon withdrawn by its return spring 21a whereby the carrier 20a slides along surface 31 to a stepped recess 32 in a guide block 30 in which it is tilted to the position C (shown). Reclosure of the circuit breaker by depression of the actuator 21 is thereby prevented, since the recess 32 ensures that the carrier 20a remains with the bridging contact 22 held substantially horizontally. The circuit breaker can only be reset by a further manual operation as by pivoting the fixed contact 23 away from its normal position to permit access to the carrier 20a, where it may be rotated back to the position A shown in Fig. 11.