Improvements in or relating to snap-action electric switches

Abstract

Abstract 792,295. Thermal switches; snap-action switches. BRITISH THERMOSTAT CO., Ltd. Aug. 1, 1956 [May 4, 1955], No. 12974/55. Class 38 (5). In a switch employing a spring blade with outer limbs 4 anchored at one end at 2 and an integral centre leaf 5 secured to the free ends of the limbs 4, with a C-spring 12 disposed between knife-edges on the free end of the leaf 5 and the anchored ends of the limbs 4, an adjustable stop 15 acts on the centre leaf 5 at its junction point with the limbs 4, whereby an upward force applied by a plunger 14 to the leaf 5 allows the C-spring to close the contact 6 on the free end of leaf 5 on to a fixed contact 7, the force excited by the C-spring progressively diminishing towards the closed position. When the operating force is removed, the blade reassumes the position shown against a stop 16. In Figs. 4, 5, the switch is shown closed, the force-transmitting plunger 23 being actuated through a forcemultiplying lever 22 by a differentially-expanding rod-and-tube thermostat 17, 18, which is inserted in a metal sleeve 20 fixed to a bush 19 having a groove receiving a spring clip 21 on the switch body. The adjustable stop comprises a rod 31 against a head 32 on which indentations 33 on the blade are urged by a spring plunger 34. The rod 31 threadedly engages a fixed bridge 36 and carries an adjusting knob 37 formed with a saw-cut 39.

Inventors

• 👤 Eric Mcgowan

Bibliographic Details