GB935952A - Improvements in thermostatically controlled electrical switching devices for refrigerators - Google Patents

Abstract

935,952. Thermal switches. BRITISH THERMOSTAT CO. Ltd. (Soc. Francaise des Thermostats). Aug. 18, 1961 [Aug. 22, 1960], No. 28964/60. Class 38 (5). A refrigerator switch is provided with a defrost button coaxial with the normal range knob but operable independently thereof to apply an additional spring loading to the thermal element so as to cause defrosting to take place. The switch disclosed in Specification 867,245 is modified by the provision of a push rod 2 and button 3 extending through the range knob 4. The end of rod 2 engages an extension 6 to the switch operating lever 19 which thus opens the contacts when the button 3 is depressed. A spring-loaded detent 8, 9, 10 holds the button in its depressed condition. Before the switch contacts are reclosed the thermal element must overcome not only the normal range spring bias on the lever 19 but also the detent 8, 9, 10. The operating temperature of the switch is thus raised causing defrosting to take place. The action of the spring 10 and therefore the defrosting temperature is variable by means of a screw 12. In a modification (Fig. 2, not shown), the action of the spring 10 varies with the setting of the range knob so that whatever the normal working temperature the defrost temperature is the same.