GB874425A - Snap-action electric switch - Google Patents

Abstract

874,425. Press-button retractive switches. CUTLER-HAMMER Inc. March 28, 1958 [March 29, 1957], No. 10055/58. Class 38 (5). [Also in Group XXXVI] A snap-action switch 20 is mounted, e.g. in the handle of a portable drill, and is operated by a slidable trigger 45. The latter loosely carries an insulating bar 58 carrying a spring- biased contact 69 arranged to bridge fixed contacts 27, 28 with a snap when the trigger is depressed. The trigger is biased " off " by a spring 65 and in this position a spring- pressed ball 67 carried by bar 58 engages an aperture 68 in a frame 47 supporting the trigger. A spring 63 in an opening in the bar 58 is engaged by the left-hand end of an opening 61 in the trigger when the latter is pressed in, so that the spring 63 is compressed. Eventually, the left-hand end of an opening 62 in the trigger engages the spring 64 of the ball 67 and forces it out of the aperture 68. The spring 63 thereupon snaps the bar 58 and the contact 69 to the right to the closed position where ball 67 engages a further aperture 72. The switch is normally moved "off" in a similar way when the trigger is released, but may be held " on " by depressing a button 74 into a recess in the trigger, or by moving a pin into an opening 76. Fixed contacts 27, 28 are formed by the heads of drive screws which hold spring clips 25, 26 in position, these clips having sharp edges which engage conductors L1 (see Group XXXVI). The leads L2 are in a non-switched pole and are engaged by a double clip 36 held in place by an insulating core 38 having a slot to allow the contactcarrying part of bar 58 to move. The recesses 23, 24 containing the clips 25, 26 are covered by a similarly-apertured cover 71 on which the contact 69 slides. The clips and fixed contacts are arranged in a base 22, on the top surface of which the trigger is slidable, the trigger being held to the base by frame 47 which has lugs 48 . . . 51 engaging recesses in the base. Movement of the trigger is limited by lugs 54, 55 thereon which move in slots 56, 57 in the frame. A modified base is described in which recess 35, housing clip 36, is omitted. Detent ball 67 may be released when spring 64 is overpowered by spring 63, or the latter may be arranged to become " solid," further movement of the trigger forcing bar 58 along.