| 摘要 |
647,653. Thermal switches. GREEN, J. D. F., and PYE, Ltd. Dec. 10, 1947, No. 32538. [Class 38(v)] In a thermal time-delay switch, a snapaction is provided by means of a resilient metal strip 62 of curved cross-section which on the application of an actuating force of sufficient magnitude collapses abruptly to a flattened form in the region of an abutment or gearing 72 to cause the rapid movement of the end of the strip. The switch is fully compensated for changes in ambient temperature. The free end of the curved strip 62 is moved to close contacts 63, 73, when a bimetallic strip 64 is heated by a heating coil 75 to a temperature at which the end 68 of the strip 64 applies sufficient pressure to cause the curved strip 62 to buckle about the abutment 72. The abutment 72 is formed by the end of a strip 69, which is bimetallic so that changes in ambient temperature, which would cause the bimetallic strip 64 to move the end of the curved strip 62, are compensated for by a corresponding movement of the abutment 72. The fixed contact supporting strip 74 is also bimetallic to enable the initial gap between the contacts 63, 73 to be maintained as the ambient temperature changes. |
