| 摘要 |
<p>An activating device (2) is intended to be mounted in a drill string in order to control the activation and deactivation of an enlargement tool used for enlarging a bore hole. In order to assemble the activating device, pistons 8 are mounted in passages (10) and spline bars (12) in which plates (22) are screwed are then slid along T-slots of the body (1), through apertures (18) of the pistons. In order to deploy the pistons (12) and cutters (6), pressurised drilling fluid is applied to the inner faces (8a) of the pistons (8). When a pre-determined pressure level is reached, screws (20) break and the pistons move from the inward position to the outwardly deployed position.</p> |
