| 摘要 |
<p>The system prevents piston movement in a cylinder under external loads or when pressure drops inside. The piston is in two parts, movable for a limited amount in relation to each other (3a,3b) and with balls (18) between them moved against the cylinder wall on their relative movement. A step on the cylinder wall prevents the two piston parts moving past it together, the balls working against it. Fluid under pressure thrusts the parts a part so that the balls can retract between them and allow them to pass the step.</p> |
