Shaft locking or manual operating apparatus

摘要

A manual operator which is useful when used with a valve or other type of device to provide either manual operation of the valve in one direction or to provide a stop against the movement of the valve away from one of its extreme positions. The device includes a ball nut (60), screw shaft (62) and balls (64) positioned in facing grooves in the nut and shaft so that relative rotation has very low friction. Thus rotation of one of the nut or screw shaft results in axial movement of the screw shaft (62) so that it can move or provide a stop. Aligned adjacent exterior surfaces are provided on a rotating part of the device and one a stationary part of the device which surfaces are engaged by a locking spring (76) which can be release from such surfaces when it is desired that the manual operator cause an axial movement of screw shaft (62). In one form of the invention the screw shaft rotates and the ball nut is stationery. In another form the ball nut rotates and the screw shaft is stationary. In a third form two locking springs are provided to lock against inadvertent relative rotation in both directions. In still another form of the apparatus, it is applied to a blowout preventer ram tail rod so that the axial movement of the tail rod is translated into rotation of a ball nut and a spring engages a surface rotating with the ball nut and a stationary aligned surface to prevent relative rotation in one direction to lock the tail rod with the piston in its inner or ram closed position.