Patent ID: 7858896
Filing Date: 2010-12-28
Classification: B23K

Abstract:
1. A spot welding gun ( 1 ) for resistance welding of workpieces ( 1 a ), including a base body ( 2 ), a bracket ( 3 ) having a C-shaped configuration, and electrode holders ( 6 ) carrying electrodes ( 7 ) arranged on the bracket, each electrode having a respective spacer and a respective pressure element arranged on an end of the electrode, each respective spacer and respective pressure element being connected with the electrode so as to be movable along with the electrode in a longitudinal direction, the pressure element exerting a force on the spacer, wherein at least one electrode holder ( 6 ) is fastened to an actuating means ( 5 ) via which the electrode holder ( 6 ) fastened thereto is displaceable together with one of said electrodes ( 7 ) in the longitudinal direction to a further one of said electrodes ( 7 ), wherein a winding device ( 9 ) including an associated strip ( 8 ) is each provided for the protection of an associated electrode of the electrodes ( 7 ), one winding device being arranged on the bracket ( 3 ) mounted on the base body ( 2 ) and another winding device being arranged on the actuating means ( 5 ), each strip ( 8 ) being arranged to be displaceable relative to the associated electrode ( 7 ) between the contact surface of the electrode ( 7 ) and a workpiece ( 1 a ), and wherein the winding device ( 9 ) associated with the displaceable electrode ( 7 ) is connected with the displaceable electrode ( 7 ) so as to follow a longitudinal movement of said electrode ( 7 ), wherein each spacer and pressure element form a respective guide for the strip, wherein the strip is located in a spaced apart relationship to the electrode above the spacer and the pressure element with the spot welding gun being not closed, wherein the spacer lifts the strip from an electrode surface or an electrode cap during or after opening of the spot welding gun on account of the pressure exerted via the pressure element, whereas the spacer is pushed back against the pressure element during a welding procedure with the spot welding gun being closed, so that the electrode or electrode cap will contact the strip, wherein a pressure or force is exerted by the spacer on the workpiece in addition to the pressure force exerted by the spot welding gun on account of the pressure element, and wherein the electrode holders ( 6 ) and the electrodes ( 7 ) comprise means for guiding the strip ( 8 ) from the winding device ( 9 ) axially along the electrode holder ( 6 ) to the electrode ( 7 ) and again axially along the electrode holder ( 6 ) back to the winding device ( 9 ).