Patent ID: 6417756
Filing Date: 2002-07-09
Classification: H01H

Abstract:
A push-button switch with overload protection and automatic reset, comprising:a housing; a conducting unit installed in the housing and including a first terminal, a second terminal, a first conducting leaf, and a flat bimetal sheet; the bimetal sheet being supported in the housing and having a movable working end, being able to move to an overlord position from a normal position in case of overload, and a fixed opening end formed with first and second legs for respectively connecting with the first terminal and the first conducting leaf; the first conducting leaf being movable between a closed position in which the second leg of the bimetal sheet is electrically connected to the second terminal and a normal-open position in which the second leg is disconnected from the second terminal; and an actuating unit installed in the housing and including: a stem provided with a heart-shaped stepping recess and slidably moving between an upper reset position and a lower set position; a locating cantilever provided with a first hand pivotally mounted at the housing and a second hand movably inserted into the heart-shaped stepping recess for locating the position of the stem; a rocking lever pivotally supported on the stem along a shaft and formed with a nose for depressing the first conducting leaf and with a resting tail opposite to the nose across the shaft; an enabling rest capable of moving between a supporting position to support the resting tail and a withdrawing position to withdraw from the resting tail, in correspondence with the location of the bimetal sheet in the normal position and the overload position, respectively; a cantilever pusher for pushing the locating cantilever away from the heart-shaped stepping recess in response to the change of the bimetal sheet into its overload position; and a lever reseating member for pushing the rocking lever into an idle position in which the resting tail could be supported by the enabling rest, during a reset course in which the stem moves from the set position to the reset position; whereby the nose can depress and release the first conducting leaf so as to make the first conducting leaf move into the closed position and the normal-open position in response to the movement of the stem to its set position and its reset position, respectively, in a situation that the enabling rest locates in its supporting position, and whereby the first conducting leaf and the stem can move to its normal-open position and its reset position, respectively, in response to a change of the bimetal sheet into its overload position.