Equalizing mechanism of welding apparatus

1. An equalizing mechanism for use in a welding apparatus that includes a fixed bracket configured to be connected to a robot arm or a mount, a pair of electrodes for applying a weld to a workpiece, a movable pressure shaft for moving one of the electrodes, and an apparatus body, wherein the equalizing mechanism connects the fixed bracket and the apparatus body, is configured to correct an error in position of the work piece and the electrodes, and comprises:

a fixed member provided on the fixed bracket;

a movable member provided on the apparatus body;

a restrictive member provided between a side face of said fixed member and a side face of said movable member such that said fixed member and said movable member are capable of relative movement only in a direction parallel to the pressure shaft;

a cutout provided on a surface of the pressure shaft facing said fixed member;

a driven lever pivotally supported on said fixed member so as to be rotatable, as the pressure shaft is moved, between a first state, in which one end of said driven lever abuts a front portion of said movable member and another end of said driven lever engages with said cutout of the pressure shaft, and a second state, in which the one end of said driven lever abuts with the front portion of said movable member and the other end of said driven lever engages with an outer surface of the pressure shaft other than the cutout;

a spring provided between a back portion of said fixed member and a back face of said movable member so as to press said movable member away from said fixed member;

wherein the pressure shaft is configured to support, at one end, the one of the electrodes and to move the one of the electrodes in a first direction to approach the other of the electrodes and so that the other end of said driven lever faces said cutout;

wherein said driven lever is configured such that in said second state, movement of said movable member is locked by said driven lever, and in said first state said movable member is movable over a predetermined distance to correct the error in position of the work piece and the electrodes; and

wherein the predetermined distance is set to be larger than a range of the error in position of the work piece and the electrodes.

2. The equalizing mechanism of claim 1 , wherein said restrictive member comprises a groove portion on one of the side face of said fixed member and the side face of said movable member and a protrusion portion on the other of the side face of said fixed member and the side face of said movable member.

3. The equalizing mechanism of claim 2 , wherein at least one of the one end and the other end of said driven lever comprises a roller.

4. The equalizing mechanism of claim 1 , wherein at least one of the one end and the other end of said driven lever comprises a roller.

5. An equalizing mechanism of a welding apparatus comprising:

a fixed bracket configured to be connected to a robot arm or a mount;

a pair of electrodes for applying a weld to a workpiece;

a movable pressure shaft for moving one of the electrodes; and

an apparatus body, wherein the equalizing mechanism connects the fixed bracket and the apparatus body, is configured to correct an error in position of the work piece and the electrodes, and comprises:

a fixed member provided on said fixed bracket;

a movable member provided on said apparatus body;

a restrictive member provided between a side face of said fixed member and a side face of said movable member such that said fixed member and said movable member are capable of relative movement only in a direction parallel to the pressure shaft;

a cutout provided on a surface of the pressure shaft facing said fixed member;

a driven lever pivotally supported on said fixed member so as to be rotatable, as the pressure shaft is moved, between a first state, in which one end of said driven lever abuts a front portion of said movable member and another end of said driven lever engages with said cutout of the pressure shaft, and a second state, in which the one end of said driven lever abuts with the front portion of said movable member and the other end of said driven lever engages with an outer surface of the pressure shaft other than the cutout;

a spring provided between a back portion of said fixed member and a back face of said movable member so as to press said movable member away from said fixed member;

wherein the pressure shaft is configured to support, at one end, the one of the electrodes and to move the one of the electrodes in a first direction to approach the other of the electrodes and so that the other end of said driven lever faces said cutout;

wherein said driven lever is configured such that in said second state, movement of said movable member is locked by said driven lever, and in said first state said movable member is movable over a predetermined distance to correct the error in position of the work piece and the electrodes; and

wherein the predetermined distance is set to be larger than a range of the error in position of the work piece and the electrodes.

6. The equalizing mechanism of claim 5 , wherein said restrictive member comprises a groove portion on one of the side face of said fixed member and the side face of said movable member and a protrusion portion on the other of the side face of said fixed member and the side face of said movable member.

7. The equalizing mechanism of claim 6 , wherein at least one of the one end and the other end of said driven lever comprises a roller.

8. The equalizing mechanism of claim 5 , wherein at least one of the one end and the other end of said driven lever comprises a roller.