Selective no-go apparatus

Claim 1

A no-go apparatus for positioning a tool at a desired location within an associated nipple in a tubular conduit in a subterranean well by preventing downward movement past the desired location, comprising; an annular landing nipple within the tubing string having a pair of vertically adjacent annular grooves formed on the inside cylindrical surface of said nipple; an annular mandrel, connectable to a work string for insertion in the tubing string; means on said mandrel for attaching the tool to be positioned; radially shiftable latch means on said mandrel resiliently urged into an expanded position in engagement with said annular grooves said latch means being axially shiftable relative to said mandrel, annular recess means on the periphery of said mandrel for receiving the latch means in a radially retracted position, said latch means being normally maintained in radially retracted position within said annular recess means by the inside bore surfaces of the tubing string and said nipple to permit movement of said mandrel and said latch means relative to said tubular string; a downwardly facing external shoulder on said mandrel spaced above said annular recess means, said shoulder being abutable with said latch means when said latch means is radially expanded; an annular surface on the periphery of said mandrel between said annular recess means and said downwardly facing shoulder, said latch means being positioned between said annular surface and at least one of said annular grooves when axially shifted into abutment with said downwardly facing shoulder; said latch means defining a pair of vertically adjacent radial projections contoured to simultaneously enter said annular grooves to oppose further downward displacement of said mandrel.

Claim 6

The apparatus defined in claims 1, 2, 3 or 4 wherein said latch means comprises a collet axially slidably mounted on the outside surface of said mandrel, said collet including an annulus and resilient latch fingers extending axially upwardly from said annulus, said latch fingers having said radial projections formed on the free ends thereof, and means on said mandrel for limiting axial movement of said collet relative to said mandrel.

Claim 8

The apparatus defined in claims 1, 2, 3 or 4 wherein said latch means comprises a collet axially slidably mounted on the outside surface of said mandrel, said collet including an annulus and resilient latch fingers extending axially upwardly from said annulus, said latch fingers having said radial projections formed on the free ends thereof, means on said mandrel for limiting axial movement of said collet relative to said mandrel, said mandrel having an exterior cylindrical surface axially movable into radially abutting relation with said collet arms after said radial projections enter said annular grooves, thereby locking said radial projections in said annular grooves.