| 摘要 |
<p>An expansible drive shaft tool mechanism is disclosed in which mutually cooperating parallel drive shafts carry tool elements that can be shifted into and locked by shaft expansion in any of selected positions along such drive shafts. Applied hydraulic pressure in a sealed chamber causes outward expansion of a flexible outer sleeve member on each such shaft to grip the tool elements. An inner sleeve member closely encircled by the outer sleeve member and joined in sealed relationship therewith at opposite end portions forms the radially thin elongated annular sealed chamber into which the pressurized hydraulic fluid is forced by the action of a plunger type hydraulic pressure source housed inside the inner sleeve member cavity. Actuation of the hydraulic pressure source plunger passing through a cylindrical fluid take-up chamber by longitudinal displacement is effected by means of a pneumatic piston energizable through a connecting line including a low pressure rotary seal or union. Hydraulic fluid that may leak past a primary seal along the plunger is taken up in the seal chamber which, of cylindrical form, incorporates a sliding piston or seal element contacting the plunger and cavity wall and urged by a return spring to exert pressure on such accumulating hydraulic fluid tending to return it to the hydraulic cylinder. Such seal chamber including the spring-returned seal element is thus available to take up leakage of hydraulic fluid seeping past the primary seal, whether caused by operating pressure or by thermal expansion of fluid in the system, and to urge the fluid back through a check valve when the pressure drops again.</p> |
