Tool for lowering or raising safety devices in oil wells

Claim 1

A tool for lowering and raising a safety device in an oil well, said tool comprising: a hollow cylindrical body (27), a driving member (28) actuated by a piston (26) and mounted to slide axially in said body in response to pulses imparted thereto by fluid pressure, a spring mounted in said body to resist movement of said driving member in response to said pulses and return said driving member to an initial position after each pulse, a rotating member (31) mounted in said body, an intermediate mechanism (29, 30, 32) for converting axial movement of said driving member to rotary movement of said rotating member, a driven member (41) mounted for axial movement in said body, means comprising a screw component (34) and an interfitting nut component (42) for converting the rotary movement of said rotating member to axial movement by said driven member, said rotating member being connected to one of said components and said driven member being connected to the other of said components, and pincer means (40) connected to be actuated by axial movement of said driven component to engage saId safety device.