Abstract: An actuator assembly for a welding gun is provided that has at least three positions in the example. The actuator assembly includes separate working and retract actuators. The working actuator includes a working rod movable between first and second positions. The retract actuator includes a retract rod independently movable relative to the working rod between third and fourth positions. The retract actuator is external to and non-concentrically arranged relative to the working actuator in the example shown. Actuation of the working and retract actuators is coordinated to provide at least three positions while enabling the actuators to be changed or modified independently from one another. A latching device is configured to selectively interlock the working and retract actuators to one another automatically in response to movement the working rod from the first position to the second position.

Abstract: An actuator assembly for a welding gun is provided that has at least three positions in the example. The actuator assembly includes separate working and retract actuators. The working actuator includes a working rod movable between first and second positions. The retract actuator includes a retract rod independently movable relative to the working rod between third and fourth positions. The retract actuator is external to and non-concentrically arranged relative to the working actuator in the example shown. Actuation of the working and retract actuators is coordinated to provide at least three positions while enabling the actuators to be changed or modified independently from one another. A latching device is configured to selectively interlock the working and retract actuators to one another automatically in response to movement the working rod from the first position to the second position.

Abstract: A low-impact drive unit operates by air under pressure. It includes aligned working and pressure chambers. The working chamber contains a working piston and a working piston rod extending from an end of the chamber. The pressure chamber contains a rear outer piston having a cylindrical recess and a central bore. An inner piston is located in the cylindrical recess and has a main piston rod extending through the bore, a bore in a separator separating the chambers, and is affixed to the working piston, so as to move together. The main rod has a longitudinal passage which supplies air from the pressure chamber to the back of the working piston under certain conditions. After the working piston rod contacts a workpiece, force of air pressure on all three pistons act on the working piston rod. An air return passage is provided to return the various components to their initial position after the working operation is complete.