GB616393A - Improvements in or relating to lever-operated electric switches - Google Patents

Abstract

616,393. Switches held set and freed mechanioally. POWELL, G. F. W., and MOLINS MACHINE CO., Ltd. Sept. 3, 1946, No. 26457. [Classes 38 (iii) and 38 (v)] A switch suitable for controlling 3-phase motors, has an operating lever 6 pivoted by a pin 5 in an oblique slot 4 formed in the arms of a metal bracket 2 attached to an apertured insulating base 1. Another metal bracket 3 supports insulating contact-carrying quadrants 9 by means of a spindle 10. The operating- lever 6 carries a pin 16 which engages driving slots 17 in the quadrants, and a roller 20 which engages grooves 19, 22 in a shaped surface formed in a block 18, the grooves corresponding, respectively, to the rest and full-speed positions of the motor. An axial movement against the action of a spring 21 must be given to the lever to raise the rollers from the groove 19 before it can be moved to the other position, but a purely-pivotal movement of the lever is sufficient to disengage the roller from the relatively-shallow groove 22. One of the quadrants, Fig. 1, carries two contacts 11 pivoted at 13 and urged into engagement with three fixed contacts 15 by springs 14, the other quadrant carrying a single contact 11 which engages a further set of three fixed contacts. The circuit may be as described in co-pending Specification 615,946. Connections (not shown), are taken from the pivots 13 to the anchorages of the springs 14 and thence by leads 26 to terminals 25. A flexible rubber hood 24 protects the switch from dust. In an alternative construction, the brackets 2, 3 and the base 1, form an integral insulating member.