| 摘要 |
<p>SPECIFICATION SECURITY DEVICES FOR ROTATABLE MEMBERS AND FLUID FLOW CONTROL VALVES INCORPORATING SUCH DEVICES A security device for a rotatable member of a machine element, such as the spindle or nut of a fluid-flow control valve, to prevent the unauthorised operation thereof. A turning member having a cylindrical surface is fitted to the valve spindle and a shroud is rotatably mounted on the member, the shroud having lugs which engage parts of the valve to prevent rotation of the shroud when the device is fitted to the valve. Projections upstand from the cylindrical surface and the turning member can be operated only by a key able to fit within the shroud and over the cylindrical surface, with recesses appropriately positioned to accommodate the projections, such that torque can be imparted to the turning member through the interengagement of at least one projection with a wall of the key defining the associated recess. A locking device including a pin spring-urged out of a bore in the base of the shroud may engage an appropriate recess in the turning member, further to enhance security. Such a lock may only be released by use of the appropriate key, to press the pin downwardly to move free of the turning member. The security device m y be modified for use with a rising stem fluid-flow control valve, and furthermore may be arranged to hold the key in the shroud until the valve has been set to one extreme position either fully open or fully closed.</p> |
