Abstract: A pneumatically operating device comprising a cylinder in which a piston can reciprocate by varying the pressure on at least one side of the piston, which piston is connected on the working side with a projecting pin passed (in gastight manner) through the working end of the cylinder, while on the side opposite the working side the piston is connected with a projecting pin passed (in gastight manner) through an end of the cylinder opposite the working end, the projecting end extending by a given length through a hole of a setting ring and having, on the side of this ring remote from the cylinder, a stop exceeding the dimensions of the hole in said setting ring, the setting ring being displaceable in the direction of length of the cylinder.

Abstract: A welding head for resistance welding, in particular for spot welding, comprising a frame to which a first welding electrode is fastened in a fixed position and a carrier for a second electrode lying substantially opposite the first electrode, said carrier being movable with respect to the frame in a manner such that the second electrode can be displaced in the direction to the first electrode, the second electrode being fastened to an element which is displaceably connected with the carrier in a manner such that it can perform a movement in a direction substantially parallel to the direction of movement of the carrier.