Patent ID: 8113544

Claim:
A fluid union comprising: a rotatable member having an axis about which the rotatable member rotates; a non-rotatable member; and an actuating member disposed between the rotatable member and the non-rotatable member; wherein the actuating member is moveable along a line between an engaged position and a non-engaged position, the line being parallel to the axis about which the rotatable member rotates; wherein the actuating member is biased towards the non-rotatable member; wherein the actuating member comprises sealing elements disposed to face the rotatable member; wherein the non-rotatable member comprises an inlet configured to receive a fluid under pressure, the inlet being configured to communicate with a recess in the actuating member and being configured to lead the fluid under pressure to the actuating member; wherein the rotatable member and the actuating member form together two enclosures at an interface between the rotatable member and the actuating member; and wherein the sealing elements press on the rotatable member such that the two enclosures are formed by the actuating member, the sealing elements and the rotatable member when the fluid under pressure actuates the actuating member.