An overload-protection push-button switch with an automatic resetting mechanism, comprising:
- a housing;
- a switching circuit installed in the housing, the switching circuit including:
- a first terminal,
- a second terminal,
- a conducting leaf, and
- a bimetallic blade, having a movable closed end which is able to move from a normal position to an overload position, and an open end formed with a first and a second legs which connect the first terminal and the first conducting leaf, respectively;
- the conducting leaf being movable between a conduction position at which the second leg of the bimetallic blade is electrically connected to the second terminal and a broken position at which the second leg is disconnected from the second terminal;
- and
- an actuating unit installed in the housing, the actuating unit including:
- a pressing stem received in the housing adapted to slide between a set and a reset positions;
- a pull-push rod having two ends;
- an enabling supporter being alternatively located in a supporting position and a tripping position in response to an allocation of the bimetallic blade in its normal position and its overload position, respectively;
- a floating rocker being formed with a nose for abutting against the conducting leaf, a toe portion to be supported by the enabling supporter, a rod-engaging hole located between the nose and the toe portion to receive one end of the pull-push rod, a guided member for guiding a floating range produced by the rocker which is restricted by the pull-push rod, and a heart-shaped stepping recess located where the toe portion is;
- a guider provided on the housing to abut the guided member so as to limit the floating range of the rocker;
- a cantilever having a fixed end fixed onto the pressing stem and a free end adapted to slide in the heart-shaped stepping recess;
- whereby the toe portion of the rocker is enabled and disabled in response to the allocation of the enabling supporter in a supporting and a tripping position, respectively in which when the toe portion is enabled, the nose presses and releases the conducting leaf to its conduction position and its broken position respectively in response to the allocation of the pressing stem in its set position and its reset position respectively under being driven by the pull-push rod and being limited by the guider;
- and when the toe portion is disabled, the nose releases the conducting leaf to its broken position;
- and
- the heart-shaped stepping recess departs from the free end of the cantilever when the toe portion is disabled so as to release the pressing stem to return to its reset position;
- and subsequently the toe portion of the rocker is pulled to a standby position so as to be supported and enabled by the enabling supporter again when the bimetallic blade returns to its normal position.