Decompression of pressure chambers, particularly the decompression of actuating pressure chambers of mine cage holding means

摘要

Means for controlling the decompression of a pressure chamber, such as an actuating pressure chamber of mine cage holding apparatus, including an outlet passage adapted to communicate with the interior of the pressure chamber; a valve seat associated with the outlet passage; a movable valve member movable into and out of engagement with the seat, the valve member or a part movable therewith being adapted to obstruct the outlet passage during at least part of the travel of the valve member away from the seat with a resistance to the release of pressure from the pressure chamber which decreases with increasing displacement from the seat; a control fluid chamber; a control piston movable in the control chamber and adapted to urge the valve member towards engagement with its seat under the influence of fluid pressure in the control chamber; and a vent from the control chamber through which fluid can escape.