US Patent 7827903 Fluid operated device with improved seal valve

A seal valve arrangement is provided for a hydraulic device (10). The hydraulic device has an inner bore (14). The seal valve arrangement includes an element (45) disposed in the bore. The element is constructed and arranged to define a fluid passage (47) so fluid can move from one side thereof to a side opposite the one side. An elastomer seal member (39) is adjacent to the fluid passage and to a seal portion (r) of the element. A spring member (41) biases the seal member to engage the portion (r) to maintain sealing of the fluid passage under certain fluid pressure conditions, and under different fluid pressure conditions, permits the seal member disengage from the portion of the element to open the fluid passage. A tipping point is disclosed as a point when a fluid pressure condition alone causes the seal member (39) to fully engage the portion of the element and fully seal the fluid passage.