Abstract: The invention relates to a hydraulic power wrench comprising a ratchet lever (16) driven by a hydraulic cylinder. According to the invention, said power wrench is provided with a friction brake (20) which operates continuously between the housing (10) and the output shaft (14). In this way, reversed rotations of the output shaft following the individual working strokes are avoided.

Abstract: The power wrench comprises a housing (10) consisting of a head portion (11) and a driving portion (12). The driving portion (12) includes a cylinder bushing (21) which is introduced into the housing (10) through an opening (22) on the side facing away from the head portion (11). The cylinder bushing (21) with the piston (28) contained therein can easily be exchanged. With a lock connection, the piston rod (29) engages the pivotable lever (17) included in the head portion so that it can be pulled off by the lever (17).

Abstract: The power wrench comprises a housing (10) consisting of a head portion (11) and a drive portion (12). The drive portion (12) contains a cylinder sleeve (21) which is introduced into the housing (10) from the side facing away from the head portion (11). A pressure channel being connected to the hose connector (41) consists of a longitudinal bore (45) extending in the wall of the cylinder sleeve (21) to supply the high pressure required to the rearward cylinder chamber (36). Thereby, it is avoided that the housing (10), in the area of support, is additionally subject to hydraulic pressure. In case of bursting of the pressure duct, the cylinder sleeve (21) is still held together by the housing (10).

Abstract: The power wrench has a substantially T-shaped configuration and comprises a transversely extending housing (10) and a headpiece (11) extending centrally therefrom. The housing (10) comprises a working cylinder (17) and an additional cylinder (21). Both cylinders guide a unit (60) having at the one end a working piston (25) and at the other end an additional piston (29). The lever (41) of the headpiece (11) engages in a coupling member (27). The additional cylinder (21) drives the return stroke. Its area is substantially smaller than that of the working cylinder (17), so that the return movement does not require much hydraulic fluid. The headpiece (11) can easily be exchanged. Its lever (41) loosely engages in the coupling member (27) of the unit (60).