| 摘要 |
A shape memory effect (SME) spring (20) is thermally responsive to currents sensed in itself or in a heater element (66) to pivot an actuator (16) against a bias spring (22) to operate a switch (32) in response to sensed currents above a given level. The actuator (16), bias spring (22) and SME spring (20) are carried by a pivotally mounted support beam (12) which is driven by an ambient temperature compensation mechanism (40,52) to change the amount of switch actuating travel of the actuator (16) in response to ambient temperature changes. The ambient temperature compensation mechanism comprises a pivotal lever (42,54) translationally coupled (42a,54a, 12b) to the support beam (12). In a first embodiment the lever (42,54) is driven by a temperature sensitive bimetal (46), and in a second embodiment it is driven by a temperature sensitive SME spring (58) biased to a reference position by an adjustable (62) spring (60).
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