Abstract: The invention relates to an apparatus for mechanically joining metal sheets, which lie flat one upon the other, by metal forming, having a tool set comprising at least one punch and one die which bounds a cavity in which the joining operation takes place, it being the case that at least one of these two tool parts can be driven via a driving force, produced by fluid supply, such that the punch displaces sheet-metal material out of a sheet-metal plane, and upsets it, under the action of deformation work, and the driveable tool part has a stop which is moved along with it and limits its penetration depth.

Abstract: A hydraulic ram including a stop system which defines a piston stroke. The stop system may be adjusted and the set position of the stop member may be coarsely read from graduation of a scale member while an adjustment ring has a finely graduated scale.