GB583722A - Improvements relating to snap-action electric switches of the enclosed type - Google Patents

Abstract

583,722. Snap - action switches. MIDLAND ELECTRIC MANUFACTURING CO., Ltd., and VICARY, A. W. Nov. 22, 1944, No. 23225. [Class 38 (v)] An enclosed snap-action switch having contacts carried by a spindle actuated by an external handle which interlocks with the lid of the switch casing, is provided with a spring catch which engages a projection on the spindle and is so arranged that if the spindle is removed and replaced incorrectly proper engagement is effected on the first subsequent actuation of the switch. Figs. 1 and 3 show a switch having a removable spindle d provided with a spigot c which engages a socket in a stub axle b. The axle b carries a handle h which has a limited freedom of movement on the axle and interlocks with the lid when the switch contacts are closed. Secured to the axle b are two plates m to which is pivoted a snap-action toggle lever arrangement n. The spring catch comprises a wire spring s surrounding the axle b between the plates m to which one end of the spring is anchored, the other end being supported by a stop u fixed to the plates m. The end of the spring terminates in a hook t which engages a projection w on an arm v carried by the spindle d. The arm v is formed with a gap x in which lies a projection y extending from the plates m. The projection y imparts the necessary rotation to the spindle d to open and close the contacts when the axle b is rotated. When the spindle, after removal, is to be replaced, it is not necessary to engage the projection w with the hooked end t of the spring catch. As the handle h is moved to the closed position the spindle d will rotate till the moving contacts are temporarily arrested by the fixed contacts whereupon continued movement of the plates m and catch will cause the hooked end t of the Catch to ride over the projection wand effect proper engagement. Fig. 6 shows a modification in which a coiled spring p engages the lever n directly to form the snap-action device and in which the projection w on the arm v engages in a gap x in the plates m.