| 摘要 |
In an air gun of pneumatic type, an exhaust valve assembly comprises a shuttle block (40) which is slidable along a housing (12) to engage a valve stem (32) extending from a valve closure element (28). In a rest position, the block is separated from an adjacent end face (58) of the stem, the block being retained in its rest position by means of a sprung ball catch (48, 52) which engages in a recess (50) in the housing. Upon firing the gun, the block becomes projected into engagement with the valve stem upon being hit by a hammer of a hammer mechanism of the gun, the valve so becoming opened. As the valve re-closes under the influence of gas pressure and a restoring spring (29), the ball catch serves to restore the shuttle block to its rest position. The provision of the shuttle block serves to isolate the valve stem from the hammer, to prevent accidental discharges of gas and to provide crisper closure of the valve. |
