| 摘要 |
PURPOSE:To restrain the change of characteristics due to the repetition of operation by specifying the material of a shape memory alloy and realizing orthorhombic phase transformation in the device wherein a circuit breaker mechanism operates with the shape change of the shape memory alloy upon the supply of overcurrent to a heater coil. CONSTITUTION:When overcurrent flows to a heater coil 9, heat generated thereby causes a rise in the temperature of a shape memory alloy spring 8. When the temperature exceeds a phase transformation start temperature level, the shape memory alloy spring 8 suddenly tends to be deformed in such a way as to push up a plunger 7. The concerned spring 8 is in a restrained condition and, therefore, when a load exceeds a sum of loads generated from the constant load bias application spring 12 of a load lever 6, the latch mechanism of a circuit breaker connected to the load lever 6 is unlocked and a circuit is thereby broken. In this case, the shape memory alloy spring 8 is made of nickel-titanium- copper metal and the phase transformation mechanism thereof related to a shape change is so made as to give orthorhombic phase transformation. |
