Patent ID: 6445273
Filing Date: 2002-09-03
Classification: H01H

Abstract:
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 first conducting leaf, and a bimetal sheet, having a movable closed end which is able to move to an overload position from a normal position in case of overload, and an open end formed with a first and a second legs which connect the first terminal and the first conducting leaf, respectively; the first conducting leaf being movable between a conduction position at which the second leg of the bimetal sheet 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 slidable pressing stem actuated to one of a set and a reset positions; a positioning unit including a cantilever and a heart-shaped stepping recess and being able to position the pressing stem in the set position when the pressing stem is pressed downward; an enabling supporter connected to the closed end of the bimetal sheet, the enabling supporter being alternatively located in a supporting position and a tripping position in response to the normal position and the overload position of the bimetal sheet, respectively; a rocking lever pivotally supported on the pressing stem along a pivoting axle provided on the pressing stem; the rocking lever being formed with a nose for abutting against the first conducting leaf, a toe portion to be supported by the enabling supporter, and a pivoting hole located therebetween for receiving the pivoting axle, whereby the rocking lever is actuated by the pressing stem; a wrecking bar for departing the cantilever from the heart-shaped stepping recess when being actuated by the rocking lever; and a lever-reseating member for abutting against the rocking lever in a stroke of the pressing stem returning back to its reset position at which the toe portion is supported by the enabling supporter; whereby when the bimetal sheet is located in its normal position, the toe portion is enabled by the enabling supporter and the nose makes the first conducting leaf be alternatively located in its conduction position and its broken position in response to the location of the pressing stem at its set position and its reset position, respectively, and whereby when the bimetal sheet is deformed to its overload position, the toe portion trips and is disabled so as to release the nose from abutting against the first conducting leaf and to make the wrecking bar depart the cantilever from the heart-shaped stepping recess, thereby the pressing stem automatically returns back to its reset position at which the first conducting leaf is in its broken position.