GB559114A - Improvements in and relating to control devices for refrigerating apparatus - Google Patents

Abstract

559,114. Thermal switches. BRITISH THOMSON-HOUSTON CO., Ltd. June 29, 1942, No. 8946. Convention date, July 1. 1941. [Class 38 (v)] An adjustment device for temperature control of, for example, refrigerators comprises an operating member moving a switch member through a resilient connection after a predetermined movement, a stop for the switch member and means for allowing greater movement of the operating member before causing movement of the switch member when desired. In the example, Fig. 3 as applied to defrosting refrigerators, the thermal element 17 operates on an arm 15 which actuates a contact arm 10 through a pivoted tail 18 and spring 22 to give snap action. An extension 26 of arm 10 has a part 26b which is moved to the right in the extreme position of the regulating knob 30 whereby a spring 32 engages a latch 34 and the contacts 13, 14 are separated to require a greater movement of the operating arm 15 before moving the switch member 10. A spring 40 additional to the normal control spring 37 applies increased resistance to movement of the operating arm, in this position. In the modification, Fig. 6, the contacts 64, 68 are on the end of spring plates 63, 69 and, in normal use, contact operation is effected through contact arm 66, extension 61 of which abuts on spring plate 63. A further extension 52 with spring latch 53, 54 for defrosting, is actuated by a press knob 50 on the adjusting knob 51. In addition a " quick-freeze " is obtained by pulling knob 50 swinging the contact arm extension 61 to the left when it rides up on a bent portion 65 of spring contact plate 63 to latch the contacts in closed position until, by an extreme contraction of the bellows the operating arm 58 opens the contacts, through the snap action 71. Specification 363,121 is referred to.