摘要 |
<p>Pressure responsive piston valve with spring controlled detent balls; a detent pressure spring extends longitudinally through the piston and urges a biasing ball against detent balls which are longitudinally offset from the biasing ball; the detent balls are driven into a detent groove in the cylinder for the piston; pressure on the piston forces the detent balls out of the detent groove; calibrating means for the spring.</p> |