Apparatus for radially expanding the end portion of a tube mode of thermoplastic synthetic material

Claim 1

An apparatus for outwardly expanding a portion of a tube made of a thermoplastic, comprising a mandrel insertable into the tube end portion and including a cylindrical core and a sheath normally surrounding said core, said core being axially removable from said sheath, said sheath being divided into at least two groups of segments each segment having an inner surface normally tightly disposed on an upper end part of said core, said segments having lateral surfaces abutting one another when said segments are in sheath forming position, the outer surface of the segments forming the sheath including a peripheral wedge tapered radially outwardly, the segments of one group being interspersed between the segments of the second group when both of said groups of segments are in said sheath forming position, the segments of one group being disposed inside the second group, a plurality of rods each being individually driven and connected to one of said segments for oppositely radially moving said segments inwardly towards the longitudinal axis of the tube portion for placing said segments closely together to form a cluster when said core is removed, and, respectively, for radially moving said segments away from longitudinal axis of the tube end portion to form a closed sheath for said core, axial moving means, said core, sheath and rods being connected to said axial moving means, said axial moving means moving said cluster of segments in and out of said tube portion, said rods moving said segments into position forming a closed sheath onto said core for assembling said mandrel for the subsequent expanding operation.

Claim 2

An apparatus for outwardly expanding a portion of a tube made of a thermoplastic, comprising a mandrel insertable into the tube end portion and including a cylindrical core and a sheath normally surrounding said core, said core being axially removable from said sheath, said sheath being divided into at least two groups of segments each segment having an inner surface normally tightly disposed on an upper end part of said core, said segments having lateral surfaces abutting one another when said segments are in sheath forming position, the outer surface of the segments forming the sheath including a peripheral wedge tapered radially outwardly, the segments of one group being interspersed between the segments of the second group when both of said groups of segments are in said sheath forming position, the segments of one group being disposed inside the second group, a plurality of rods each being individually driven and connected to one of said segments for oppositely radially moving said segments inwardly towards the longitudinal axis of the tube portion for placing said segments closely together to form a cluster when said core is removed, and, respectively, for radially moving said segments away from longitudinal axis of the tube end portion to form a closed sheath for said core, axial moving means, said core, sheath and rods being connected to said axial moving means, said axial moving means moving said cluster of segments in and out of said tube portion, said rods moving said segments into position forming a closed sheath onto said core for assembling said mandrel for the subsequent expanding operation.

Claim 4

An apparatus for outwardly expanding a portion of a tube made of a deformable material, comprising, in combination, a mandrel removably insertable coaxially into said tube, said mandrel including a core and an expansion sheath removably disposed on said core, said sheath including segments radially movable to and from a sheath forming position and comprising at least two groups of such segments, the segments of the two groups alternating in the sheath forming position, each segment of one group having lateral surfaces diverging inwardly and each segment of the other group having lateral surfaces diverging outwardly, said lateral surfaces of the adjoining segments abutting one another when said segments are in sheath forming position, said core being movable to and from a position within said sheath, first axial drive means in driving connection with said core and operable for moving said core to and from said sheath, a plurality of radial drive means in driving connection with said segments and operable for radially displacing one group of segments in advance of the other group of segments when said core is axially displaced from said sheath, and second axial drive means coupled with said plurality of radial drive means and operable for inserting in concert with said first axial drive means said mandrel into said tube and for axially removing the radially inwardly displaced segments from the expanded portion of said tube.

Claim 5

An apparatus for outwardly expanding a portion of a tube made of a deformable material, comprising, in combination, a mandrel removably insertable coaxially into said tube, said mandrel including a core and an expansion sheath removably disposed on said core, said sheath including segments radially movable to and from a sheath forming position and comprising at least two groups of such segments, the segments of the two groups alternating in the sheath forming position, each segment of one group having lateral surfaces diverging inwardly and each segment of the other group having lateral surfaces diverging outwardly, said lateral surfaces of the adjoining segments abutting one another when said segments are in sheath forming position, said core being movable to and from a position within said sheath, first axial drive means in driving connection with said core and operable for moving said core to and from said sheath, a plurality of radial drive means in driving connection with said segments and operable for radially displacing one group of segments in advance of the other group of segments when said core is axially displaced from said sheath, and second axial drive means coupled with said plurality of radial drive means and operable for inserting in concert with said first axial drive means said mandrel into said tube and for axially removing the radially inwardly displaced segments from the expanded portion of said tube.