Device for providing hollow plastic bodies, and especially plastic pipes, with a reinforced sleeve-end provided with a bead

Claim 1

Apparatus for forming an internal peripheral recess adjacent an end of a hollow tubular thermoplastic body comprising: a pair of separable co-operating jaw members defining a cylindrical hollow body having an inside surface providing a circumferential radial groove; a moulding means positioned co-axially within said hollow body and comprising: a mandrel adapted to engage a portion of said thermoplastic body against said jaw members, and an end portion axially spaced from said mandrel and defining an upsetting ring adapted to engage a radial end surface of said body, said mandrel and said end portion being relatively movable axially and being connected respectively to opposite ends of a short flexible tubular forming ring positioned radially inwards of said groove and defining a pressure chamber between said mandrel and said end portion; means for producing relative axial movement between said mandrel and said upsetting ring; and means operable upon relative axial movement of said mandrel and said upsetting ring towards each other simultaneously to develop fluid pressure within said chamber to extend said forming ring radially outwards thereby moulding said recess in the end of the tubular thermoplastic body by deforming outwards into the groove in the jaw members the material of the thermoplastic body displaced by said upsetting ring.