GB740664A - Improvements in and relating to electric switch mechanism responsive to temperature or other conditions - Google Patents

Abstract

740,664. Thermal switches; fluid actuation of switches. GENERAL ELECTRIC CO. Nov. 17, 1953 [Nov. 19, 1952], No. 31881/53. Class 38(5) A pressure, temperature or other condition-responsive switch, e.g. for controlling a refrigerator, comprises a fixed contact 17 mounted on a . support 5, a cooperating movable contact 20 mounted by means of a leaf spring 18 on the support and biased to engage the fixed contact, an operating lever 24 pivoted at 22 for movement between contact-open and closed positions, a toggle spring 28 continuously biasing the lever to the contact-closed position, and a further spring 45 biasing the lever to the open position. As the refrigerator temperature rises, a bellows 15 expands, and at a certain temperature, e.g. 36‹F, the combined effect of the bellows and the spring 28 overpowers the spring 45 and the lever 24 is moved upwards from the position shown in Fig. 1 to allow the contacts to close. A compressor motor is thus energized so that the refrigerator temperature gradually drops and the bellows is contracted by the spring 45 until the lever 24 is moved down to re-open the contacts. The strength of spring 45 is factory adjusted by a cam 46 bearing on the lever 24 to fix the upper position of the lever whose end moves with play in the space between the spring 18 and its turned-over free end 19, Fig. 2. Specification 738,497 is referred to.