GB1052334A - - Google Patents

Abstract

1,052,334. Thermal switches. CALOR APPAREILS ELECTRO - DOMESTIQUES. April 28, 1964 [May 9, 1963], No. 17585/64. Heading H2B. [Also in Division G1] A thermostat for an electric iron utilizes the difference in expansion between the iron soleplate 10 and a rod 12 of substantially non- expanding material, e.g. " Invar " (Registered Trade Mark) to actuate switch contacts 35, 64 to control the heater for the iron. The rod 12 is fixed at one end to a member 14 on the sole-plate 10 and at the other end is secured to a pin 49, engaging a lever 46, the lever 46 being pivoted at 50 to a fixed assembly on the plate 10. The fixed assembly 24 carries a cam 32 on a spindle 28 and an insulating block 42 supporting blades 34, 36. The blade 36 carries an insulating block 44 engaging the cam 32, and is provided with a knife edge 38 to contact the blade 34. A spring 40 is provided between the blades 34, 36 and the blade 34 is snap-acting between the position shown in Fig. 1 where the contacts 35, 64 are in engagement and a position wherein they are disengaged. The lever 46 carries by way of an insulating block 58 a movable assembly 56, with the contact 64 and an adjustable insulating stop member 62. A spring blade 52 acts on the lever 46 although a coil spring may be substituted. In operation, as the soleplate expands the movable assembly moves so that the contact 64 forces the blade 34 to pass from the position shown to its other position to cut-off the supply to the iron heater. The temperature at which this occurs is controlled by the position of the cam 32 which is adjusted normally by the operator. As the temperature falls the stop member 62 will ensure the return of the contacts to their closed position. An insulating stop member 70 is also provided on the assembly 24. In an alternative embodiment the lever 46 may incorporate pivot-pin connections with the rod 12 and assembly 24.