Driving device for a wireline conveyed tool

摘要

A driving device for assisting the movement of a wireline tool is adapted for mounting on a toolstring (3) in such a way as to allow relative longitudinal movement between the device and the toolstring (3). The device includes a spring portion (2) and a gripping portion (1) and in use upward force applied via the wireline causes the gripping portion (1) to grip the wall of a casing. When the upward force is released, the energy released by the spring (2) drives the toolstring (3) downwards which in turn "picks up" the gripper portion (1) and spring portion (2); the process can be repeated.