GB1185612A - Snap Action Electric Switches - Google Patents

Abstract

1,185,612. Snap-action switches; retractive switches. CUTLER-HAMMER Inc. 3 Jan., 1969 [5 Jan., 1968], No. 455/69. Heading H1N. A snap action switch, Fig. 4, comprises three pairs of fixed contacts 6, 8, 10 and two movable contacts 14 pivoted on centre contacts 8 for rocking movement to contact the outer fixed contacts 6, 10 and an actuator 16 mounted on movable contacts 14. Actuator 16 has two pivot ridges 16b, 16c and the line of action of compression spring 18 in the position shown is from centre part 22a of operating member 22 to pivot 16b. Operating member 22 has a downwardly projecting arm 22c on either side of spring 18 and when member 22 is pushed down by a member such as push button 12, operating member 22 slides vertically downwards and arms 22c engage the V-shaped recess in the right-hand half of the top of actuator 16 and moves it clockwise until the point of contact 16e between actuator 16 and spring 18 has moved over the centre line of action of compression spring 18 when spring 18 snaps actuator 16 clockwise on to pivot 16c pressing movable contact 14 clockwise to contact fixed contact 10. When push button 12 is released spring 18 restores operating member 22 to its position at the top of the housing. The line of action of spring 18. now extends from centre part 22a of member 22 to pivot 16c and when member 22 is again depressed arms 22c engage the V-shaped recess in the left-hand half of the top of actuator 16 to snap it anticlockwise. The fixed and movable contacts are of brass with silver contact tips. A cover 4 is held on housing 2 to retain the parts by two arms 4b. Arms 22c provide positive actuation in the event of the contacts welding. In a second embodiment, a retractive switch, Fig. 8, operating member 24 is the same as operating member 22 except that it has two integral ears engaging in recesses in the top left-hand corners of the housing such that when member 24 is depressed it pivots clockwise instead of moving vertically downwards and arms 24c always engage the lefthand V-shaped recess in the top of actuator 16 snapping it anticlockwise, and when push button 12 is released spring 18 pivots member 24 back so that arms 24c engage the centre hump at the top of actuator 16 to move the tip of the hump where it engages spring 18 over centre so that spring 18 snaps it back clockwise.