GB842485A - Improvements in or relating to electric switches and covers therefor - Google Patents

Abstract

842,485. Retractive switches; snap-action switches; momentary-contact switches. ELECTRICAL APPARATUS CO. Inc. Nov. 25, 1957, No. 36636/57. Class 38 (5). A switch base 32 of insulating material carriers two fixed contact members 111, 112, and a spring blade moving contact member 114 (Fig. 3), by means of hollow rivets 61, 62 and 63, respectively. The rivets are internally threaded to accommodate terminal screws and the end rivets 61 and 63 also accommodate screws 161 and 162 which secure an insulating cover 33. Screws 161, 162 may also act as terminals or may be of nylon to provide a fully insulated cover. An actuator 181 is slidably carried in cover 33 in alignment with the rivet 62 which may support a spring 186 to assist in retraction. A spring 185 changes the leverage of the moving contact blade 114 during operation and thus provides a wiping action of the contacts. One of the stationary contact members 111 or 112 may be omitted if a single-throw action only is desired. The switch may be mounted on an insulating panel by means of terminal strips fastened under the screws in rivets 61, 62 and 63 (Fig. 12, not shown), or by replacing screws 161, 162 by studs each having a nut to hold the cover 33 and another for panel mounting (Fig. 13, not shown). Alternatively small bolts through holes 95, 96 in the cover 33 may fasten the switch to supporting members (Fig. 14, not shown). Bolts through lateral holes 65 and 66 in the base 32 may be used to mount the switch or to join several switches together. A spring arm carrying a roller on its free end may be secured under screw 161 to engage the actuator 181 and operate it in accordance with a cam, for example, followed by the roller (Fig. 15, not shown); or a rigid member having a spring-loaded roller-carrying plunger to engage the actuator 181 (Fig. 16, not shown), may be secured to the top of the switch by means of screws 161, 162. In the embodiment of Fig. 17, the contact blade 114 is replaced by a snap-action assembly comprising a rigid frame 301 and a bowed spring strip 302. In this case the hollow rivet 62 carries a second actuator 312 for returning the switch to the position shown. In a further embodiment (Fig. 19), a modified snap-action assembly co-operates with a stop member 328 to restore the moving contact against member 111 on the one downward operation of the actuator and thereby provides only a momentary contact with member 112.