Patent Number: 
Section: claims

1. 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); andwherein 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. 2. Apparatus as defined in claim 1 further comprising:a source of electrical current (1200);an electric actuator and drive (1050) electrically connected to the source of electric current (1200);said magnetic ram (400) including a coil (500) electrically connected to the source of current (1200) for generating a magnetic field; andcontrols for switching and regulating the flow of electric current (1200) associated with the source of electrical current (1200) and electrically connected to the electric actuator and drive (1050) and the coil (500). 3. Apparatus as defined in claim 2 further comprising:an axially movable, radially expandable collet (350) mounted on the push rod (1000) and normally located radially inwardly of the collet and mandrel (700) for expanding the collet and mandrel (700) into engagement with the inner cylindrical tube (100).