Equalizing mechanism for robotically carried spot weld guns

Abstract

A spot welding apparatus having a welding gun with movable and fixed electrodes carried on an articulating wrist, the apparatus comprising: a) a robotically actuated articulating wrist carrying the gun for movement to and from a welding position for a workpiece; b) a primary cylinder assembly connecting the wrist to the movable electrode of the gun for imposing pressure by such movable electrode to the workpiece and to the fixed electrode during a welding stroke toward the workpiece; and c) a fixing cylinder assembly connecting the wrist to the fixed electrode, the fixing cylinder assembly having (i) a fixing cylinder housing with a movable fixing piston therein connected to the fixed electrode of the welding gun and having a fixing piston stop, (ii) a primary balancing spring acting between the fixing cylinder housing and the movable fixing piston to carry the weight of the gun, (iii) structure for introducing a fixing air pressure into the fixing cylinder housing to urge the fixing piston to a position locked against the fixing piston stop, and (iv) a secondary modulating device acting between the fixed electrode of the gun and the fixing cylinder housing to dampen vibratory movement of the gun upon release of the fixing air pressure for initiation of the welding stroke.

Dependencies are inferred from the claim text.