Abstract: The invention relates to a process for the production of coupling pieces which possess an undercut annular groove optionally provided with a sealing ring, in which process a sleeve, having an internal diameter which increases in steps towards the open end, is initially preformed, the terminal part of the sleeve is postformed in order to form the annular groove, after having optionally introduced a sealing ring into the preformed sleeve, and, during preforming, only the terminal part of the preformed sleeve is kept at the deformation temperature and the remainder of the preformed sleeve is cooled, the terminal part of the preformed sleeve being cooled after postforming.

Abstract: Process and device for the forming, on the end of a pipe made of a thermoplastic, of a coupling piece possessing an undercut annular groove intended for receiving an annular seal, according to which process and device the coupling piece is initially preformed by means of a forming core which possesses an annular rib for forming the annular groove, the core then being withdrawn from the partially cooled coupling piece by virtue of an elastic deformation of the part possessing the groove, by means of the rib of the forming core, and this part being kept at the elastic deformation temperature, and according to which this part is subjected to a postforming operation, before it has completely cooled, by means of a postforming ring.

Abstract: Pipe coupling for the high-strength coupling of plastic pipe ends, a coupling sleeve having internal sawtooth ridges which mesh with counter profiles on the pipe ends.

Abstract: A coupling device for coupling plastic pipe to metal pipe. A metal connecting piece has one end arranged for connection to a metal pipe, and a stop at the other end. A plastic coupling member around the connecting piece can be welded to the plastic pipe and has an open inner sealing chamber for a sealing ring. A hold-down member screwed on the connecting piece applies direct axial force onto the ring in the sealing chamber and presses the coupling member against the stop at the same time.

Abstract: An apparatus for forming a bell end having a thickened portion on a pipe composed of thermoplastic material, in which an annular shaping space is established between a shaping sleeve and a mandril having an elastic shaping ring, the height of the shaping space increasing along transition portions of the surfaces of the sleeve and the mandril to a region defining a sealing chamber and then decreasing again.

Abstract: A method of shaping a bell end on a pipe of thermoplastic material, in which an elastic shaping ring is expanded radially in its operative position during the shaping of the bell end, and removed from the formed bell end by radial contraction. Part of a shaping mandril is moved to create a cavity into which the ring is free to contract.

Abstract: Tapping tee for a main pipe having integral coupling means for coupling to branch pipes made of flexible or relatively inflexible synthetic materials. A branch-receiving socket has a support pipe fitting snugly inside the branch pipe, and an integral sleeve having a part fitting snugly to the branch pipe outside, and a part with an enlarged bore for a sealing means.

Abstract: A bell end on a pipe of thermoplastic material has variable wall thickness in the axial direction, the maximum being where the inner wall acts as a sealing face. The bell end can be formed by upsetting the pipe wall into the cavity between a mandril and a shaping sleeve.

Abstract: A mandril for shaping a bell end on a pipe of thermoplastic material, having an elastic shaping ring which is expanded radially in an operative position during the shaping of the bell end and which can be removed from the bell end by radial contraction. The mandril assembly comprises a plurality of parts which are profiled and slidable with respect to each other such that in the operative position the shaping ring is locked radially and axially, and in the removal position the shaping ring can retreat into a chamber formed between the slidable parts.