Improvements in or relating to thermostatic control means particularly for electric hand irons

Abstract

Abstract 671,069. Thermal switches. GENERAL ELECTRIC CO., Ltd., and HUMPHREY, R. Sept. 1, 1950. [Sept. 2, 1949] No. 22804/49. Class 38 (v). A thermal switch, particularly for an electric hand iron, comprises a bimetallic strip 23 clamped at one end, a substantially rigid member 25 connected at one end to the free end of the bimetallic strip and resting at its other end on a rotatable cam 28, and a rigid insulating member 34 to transmit the motion of the member 25 to a switch of the trifurcated spring blade type. Lateral displacement of the member 25, which may be of stainless steel, is prevented by a tongue 24 at the end of the bimetal strip engaging in an aperture in the end of the member 25, which at its other end has arms engaging round the adjusting spindle '29 for the cam 28. The member 34 which may be a glass rod is seated at its lower end in a thimble 32 carried in an aperture 53 in the member 25 and at its upper end passes through an aperture 50 to engage the central tension limb of the switch blade 42. As the temperature rises, the free end of the bimetallic strip 23 curls upwards causing the member 25 to pivot about its point of engagement with the adjusting cam 28, so raising the rod 34 to cause the blade 42 to move over its dead centre position to open contacts 44, 45. The operating temperature of the switch is adjusted by rotating the cam 28 by means of a knob 31 on the spindle 29, the cam surface changing in height in a direction at right angles to the plane of the bimetallic strip. The provisional specification states that the spindle 27 may be axially adjustable to permit initial calibration of the switch to be made.

Inventors

No inventors recorded.

Bibliographic Details