Patent ID: 7128560

Claim:
An expansion tool apparatus for pliers used for producing sockets at ends of a pipe, the apparatus comprising: a plurality of sector-shaped jaws movable between a first position in which said plurality of sector-shaped jaws define a cylindrical end piece and a second position in which said plurality of sector-shaped jaws are moved radially outwardly from said first position; a conical needle means axially insertable in a conical recess within said plurality of sector-shaped jaws for moving said plurality of sector-shaped jaws from said first position to said second position, said conical needle means suitable for being actuated by the pliers; and an insert axially movable between said plurality of sector-shaped jaws, said insert having a conical cavity at one end which is cooperative with said conical needle means, said insert having a conical form at an opposite end thereof, said conical form conforming to said conical recess, said conical form and said conical cavity being of substantially identical coning angles but of different diameters, said conical needle means for urging said insert axially in said conical recess of said plurality of sector-shaped jaws, said insert having a narrowing with a frustoconical surface formed at an end of said cavity opposite said one end of said insert, said frustoconical surface conforming to a portion of an external surface of said conical needle means.