Patent ID: 7346141

Claim:
Apparatus for placing and moving a spacer ( 300 ) into and along an annulus ( 150 ) defined by inner and outer coaxial cylindrical tubes ( 100 , 200 ), said apparatus comprising: a first push rod ( 1000 ); a radially expandable generally toroidal pusher ( 600 ) surrounding and located at a first axial position on said push rod ( 1000 ); a collet and mandrel ( 700 ) operatively associated with the push rod ( 1000 ) axially adjacent the pusher ( 600 ) for engaging an end of said inner cylindrical tube ( 100 ) and providing a generally frusto-conical surface from the outer diameter of the push rod ( 1000 ) to the outer diameter of the inner cylindrical tube ( 100 ); a second push rod ( 1006 ) supported for axial movement by said push rod ( 100 ); a magnetic ram operatively associated with the second push rod ( 1006 ) for movement therewith from a first position located radially inwardly of the pusher ( 600 ) to a second position located within the inner cylindrical tube ( 100 ) for creating a magnetic coupling with the pusher ( 600 ) and moving the pusher from said first location on the push rod ( 1000 ) into the annulus ( 150 ); and wherein the pusher ( 600 ) comprises a plurality of arcuate ferromagnetic segments ( 601 , 603 ) forming a generally toroidal, radially expandable ferromagnetic ring surrounding the push rod ( 1000 ) and normally located axially adjacent the fixed end ( 708 ) of the collet and mandrel ( 700 ) movable under the influence of a magnetic field from the electromagnetic coil ( 500 ) along the collet and mandrel ( 700 ) toward a radial shoulder ( 706 ) on a collet and mandrel finger ( 702 ) and into the annulus ( 150 ) between the inner and outer cylindrical tubes ( 100 , 200 ) and thereafter movable under the influence of a magnetic field from the electromagnetic coil ( 500 ) to position a toroidal spacer ( 600 ) in said annular space.