GB684137A - Improvements in thermostatic and circuit breaker devices - Google Patents

Abstract

684,137. Thermal switches. PIERCE FOUNDATION, J. B. March 5, 1951 [March 7, 1950], No. 5276/51. Class 38 (v) In a thermal switch having a bimetallic dished disc 30 fixed at its centre to a post 27, its periphery is engaged and biased by a dished spring disc 34 which serves to maintain good contact between the discs during the initial 'creepage' of the bimetallic disc just prior to its snapping over. The two discs may be connected to terminals of a circuit so that current passes through them, heating the disc 30 which thus snaps into the open position at a given overload. Adjustment of the spring pressure of the disc 34 may be made by rotating a knob 36 and the disc 34 is loosely mounted so that it may be rotated about its axis should sparking tend to occur always at the same points. In modifications, a second spring disc may be arranged on the other side of the bimetallic disc thus producing a two-way switch, Fig. 7 (not shown); the spring disc may overlap the bimetallic disc, Fig. 3 (not shown); the spring disc may be a bimetallic disc and produce ambient temperature compensation, Fig. 4 (not shown); the discs instead of being themselves switch contacts may actuate contacts, Figs. 8, 9 (not shown).