Pressure medium pliers

Pressure medium pliers for clamping rings, comprising a pressure medium connection (71) and a pressure medium valve (60, 61, 66, 67, 69) connected thereto, several pistons (32, 41, 42) controlled by the pressure medium valve, a traverse member (28) drivable by the pistons, pivoted pliers members (12, 13) at the inner lever ends (14, 15) of which the traverse member engages for pivoting them, the pressure medium valve (60, 61, 66, 67, 69) having a valve pin (61) which is driven shiftably in the traverse direction of the piston movement and operatable by a release trigger (75), the valve pin blocking the connection of the pistons (32, 41, 42) with the pressure-medium connection and connecting those with a lower pressure level in a rest position and blocking the connection of the pistons with the lower pressure level and connecting those (32, 41, 42) with the pressure medium connection in a working position being reachable by operation of the release trigger (75), a switching bar (52) which is held in a slideway (49) movable in the direction of the pistons (32, 43, 44) and which is mechanically biased by a spring (55) towards the valve pin (61), the switching bar (52) having an outer step as cam (53) and the pistons having a bored shaft which receives the switching bar (52) and has an inner step as stop (54) corresponding to the outer step (53) for engaging the switching bar in the last part of its movement for closing the pliers members (12, 13), and the valve pin (61) having a locking seat (62) into which the switching bar (52) snaps under action of the spring (55) at movement of the valve pin (61) from the rest into the working position and which the switching bar (52) releases at its engaging by the piston (42), characterized in that an intermediate wall (37) is fixedly mounted at an inner wall of the housing between pressure medium valve (60, 61, 66, 67, 69) and pistons (32, 41, 42), with the spring supported at the intermediate wall (37), and that the piston (42) arranged adjacent to the intermediate wall (37) is T-shaped and supports its shaft (40) which is directed to the traverse member and provided the inner step at the following piston (41).