| 摘要 |
<p>A fluid-pressure-operated reciprocating drive device comprising a housing (11) defining a chamber (20) separated into two parts (20a, 20b) by a movable partition member (21) carrying a valve (32) resiliently biased to a closure position in which the two parts (20a, 20b) of the chamber (20) are isolated from one another by the partition member (21), the partition member (21) being movable between two end positions and there being means for opening the valve (32) when the partition member (21) is at or in the vicinity of one of the two end positions whereby to open communication between the two parts (20a, 20b) of the chamber (20). The partition member (21) may act to drive a pump piston (27) for delivering a fluid. A particular application for such a vacuum-operated pump is in the delivery of wash fluid from a reservoir or a vacuum cleaner to the region of a working head thereof for use in shampooing carpets or the like.</p> |
