Dressing device for tip of welding gun

A dressing device for a tip of a welding gun, comprising:

• a base;
• a driving device movably provided on said base and being movable relative to the base from a nondressing position into a dressing position;
• dresser means movably supported on said driving device for movement with said driving device and relative to said base, said dresser means being movable relative to said driving device along a direction which is generally parallel to the direction of relative movement between said driving device and said base;
• said dresser means including rotatable blade means for dressing said tip and air motor means for effecting rotation of said blade means;
• on-off valve means for controlling flow of air to said air motor means;
• control switch means coacting between said driving device and a body of said dresser means for controlling the actuation of said on-off valve means;
• timer circuitry means responsive to pressure supplied to said air motor means for controlling the duration of the dressing operation when the blade means is rotatably engaged with the tip;
• changeover valve means for supplying air to said driving device to control movement thereof between said dressing and nondressing positions, said changeover valve means being connected to said timer circuitry means;
• a quick return mechanism mounted on said driving device and coacting with said base for effecting quick return of said driving device from said dressing position to said nondressing position, said quick return mechanism including pneumatic cylinder means;
• and
• control valve means for controlling flow of air to said pneumatic cylinder means, said control valve means being connected with said timer circuitry means.