Apparatus for facilitating the descent of cable-suspended well tools through deviated well bores

Claim 1

Apparatus adapted for passage through well bores having deviated intervals therein and comprising: a well tool having a body member with a longitudinal bore in the upper end thereof; a supporting member slidably disposed in said longitudinal bore and adapted for relative axial movement therein upon imposition of axial loads thereon; stop means arranged on said members for limiting axial movement of said supporting member to a span between upper and lower spaced positions within said longitudinal bore; a suspension cable including electrical conductor means, and an armor sheath operatively arranged around said conductor means and adapted for carrying axial compressive loads of a predetermined magnitude; means coupling said armor sheath to said supporting member and adapted for transmitting axial compressive loads from said armor sheath to said supporting member in its said upper position and responsive to axial compressive loads of a lesser magnitude imposed on said supporting member for allowing said supporting member to move toward its said lower position and impose such axial compressive loads on said body member; and switching means arranged on said well tool and including a switch mounted on one of said members and operatively coupled to said electrical conductor means, and switch-actuating means mounted on the other of said members and operatively arranged for selectively operating said switch only when said supporting member moves to its said lower position to provide an electrical signal designating that axial compressive loads are being transmitted from said armor sheath to said body member.