TAMPER-PROOF LOCKING MECHANISM FOR QUARTER TURN VALVES

摘要

A tamper-proof locking mechanism for a rotatable control device, such as a quarter turn valve including a valve member connected to a stem journalled in a body housing the valve member and an operating handle connected to the stem for rotating the valve member between open and closed positions. The locking mechanism includes a pair lugs on the valve body at circumferentially spaced locations corresponding to the locations of an intermediate portion of the handle when the valve member is in the open and closed positions. A slider member is slidably mounted on the intermediate portion of the handle for reciprocative movement between a locked position and an unlocked position. The slider member includes a latch element having an open portion for receiving the lugs and arranged to restrain both rotational and axial movement of the handle when the handle is in the open or closed position and the slider member is in the locked position. When the slider member is moved to the unlocked position, the handle can be moved freely between the open and closed positions. An aperture in the intermediate portion of the handle adjacent the slider member can receive the shackle of a padlock which is engaged by the slider member when movement of the slider member from the locked position is attempted.