Pipe cutting mechanism

Claim 1

A mechanism for cutting pipe from the inside comprising: a. a plate rotatably mountable on the end of the pipe, said plate having an axial bore and means for axially aligning the bore of said plate with the longitudinal axis of the pipe when said plate is mounted on the end thereof; b. an elongated tubular arbor axially slidable within the bore of said plate and fixed for rotation with said plate; c. means on said plate for locking said arbor against axial sliding movement relative to said plate; d. a cutter head on one end of said arbor, said cutter head comprising, an adapter plate transversely affixed to one end of said arbor and having a recessed groove with closed ends formed in the surface thereof which faces away from said arbor and having a substantially rectangular slot extending from the recessed groove toward said arbor, said adapter plate having an axial bore formed therethrough which communicates with the interior of said tubular arbor, and a housing demountably attached to said adapter plate, said housing having an open ended channel formed in the end thereof which faces said adapter plate and having a recessed groove with closed ends formed in the bottom of the channel thereof, the channel and the groove of said housing extending in the same direction as the groove of said adapter plate, said housing having an axial bore formed therein and a pair of diametrically opposed axially extending guide slots radially extending from the axial bore thereof, the guide slots of said housing in alignment with the rectangular slot of said adapter plate in a plane transverse with respect to the extending direction of the channel and recessed groove of said housing and the recessed groove of said adapter plate; e. a pair of cutter assemblies mounted in oppositely facing directions within said cutter head, said pair of cutter assemblies in abutting engagement with each other for positioning thereof in a retracted position within the periphery of said cutter head, said pair of cutter assemblies radially movable in diametrically opposite directions to an extended position of protruding beyond the periphery of said cutter head; and f. expander means within said cutter head and passing around said pair of cutter assemblies and extending from said cutter head through said arbor, said expander means axially movable to engage and radially move said pair of cutter assemblies from the retracted to the extended position thereof.