GB690659A - Electric snap switch - Google Patents

Abstract

690,659. Snap-action switches. RANCO, Inc. May 4, 1951 [June 17, 1950], No. 10480/51. Class. 38(v) A switch in which the contact-pressure is maintained up to the instant of snap-action and in which the required movement of the actuating member is small, comprises a U-shaped strip 20 pivotally mounted on a bracket 21 and carrying a contact 22 engageable with fixed contacts 12, 15. A U-shaped toggle arm 25 has notches 27 in the ends of its legs whereby it is pivoted to the strip 20, the yoke end of the arm 25 being connected by a spring 26 to an actuator 32 having pivot notches 35 which engage lugs 37, 38 on the bracket 21, pivoted movement of the arm 25 being limited by flanges 29, 30 thereon which engage a tongue 31 on the bracket. In the switch position shown in Fig. 3, the spring 26 causes flange 30 to engage the tongue 31 and contact 22 to engage fixed contact 12. Depression of the actuator 32 moves the spring 26 into alignment with the toggle arm 25, in which condition there is no pressure on the tongue 31, but contact pressure is maintained since the line of action, a, a, of the spring on the strip 10 is still inclined to the latter. Continued movement of the actuator causes the spring to move over-centre relatively to the toggle arm 25 whereupon the flange 29 engages the tongue 31. The spring is thereby moved over-centre relatively to the strip 20 which pivots to engage the contact 15, Figs. 4-6, (not shown). Release of the operating pressure on the actuator permits it to be returned by the spring to its original position.