An actuator designed for use with a welding gun of the type having a first
electrode movable in a straight line toward and away from a second
electrode supported by a welding arm. The actuator includes a housing with
a first and second end. A bushing with a generally square opening defined
therethrough is supported in the first end of the housing. An actuator rod
extends through the square opening in the bushing and has a first end
inside the housing and a second end disposed external to the housing. The
actuator rod has an external surface with a generally square cross section
such that the external surface engages the square opening to prevent
rotary motion of the rod with respect to the housing. A drive mechanism is
disposed in the housing and is operable to move the rod with respect to
the housing. The drive mechanism may be a pneumatic actuator or a rotary
screw drive.
