| 摘要 |
<p>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 17 having a cylindrical surface 21 is fitted to the valve spindle 11 and a shroud 12 is rotatably mounted on the member 17, the shroud having lugs 13 which engage parts of the valve to prevent rotation of the shroud when the device is fitted to the valve. Projections 28 upstand from the cylindrical surface 21 and the turning member can be operated only be a key 29 able to fit within the shroud 12 and over the cylindrical surface 17, with recesses 31 appropriately positioned to accommodate the projections 28, 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 25 spring-urged out of a bore in the base 14 of the shroud may engage and appropriate recess 27 in the turning member 17, further to enhance security. Such a lock may only be released by use of the appropriate key 29, to press the pin 25 downwardly to move free of the turning member 17. The security device may 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> |
