Abstract: First and second hollow bodies each having at least one opening are joined by first forming a fracture zone in a joint region of the first body and then juxtaposing the bodies in a closed cavity of an internal high-pressure shaping tool with the second body spaced from and open toward the fracture zone of the first body. The first body is then internally pressurized with a hydraulic medium until a burst pressure at the fracture zone is exceeded and the first body ruptures and is deformed outward at the fracture zone into engagement with the second body. The medium then flows through the ruptured fracture zone into the second body.

Abstract: A press frame has an upper frame member, a lower frame member, a platen having a tool mounted thereon and disposed at the lower frame member, a working piston-and-cylinder unit disposed at the upper frame member and centered on an upright axis, the piston of the working piston-and-cylinder unit being displaceable and formed with a chamber in alignment with the platen and adapted to receive the tool, an elastomeric pad disposed in the chamber for evenly distributing pressing forces acting on a workpiece on the tool upon the supply of a hydraulic medium under pressure to the piston, whereby an outward force from the chamber is applied to the piston, with means forming a ring space between the piston and cylinder of the working unit at least in part peripherally surrounding the chamber, and means for supplying the ring space with the pressurized hydraulic medium, whereby a pressing force is applied to the piston to counterbalance the outward force.