The slide valve includes a pre loaded spring, capable in the absence of other force of moving the slide valve to {HEAD ~ its closed position} to lock {TAIL ~ the member} against movement 
to lock
The slide valve includes a pre loaded spring , capable in the absence of other force of moving the slide valve to { HEAD ~ its closed position } to lock { TAIL ~ the member } against movement
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH