Abstract: The power wrench comprises a housing (10) with a rearward housing member (12) which forms a protection against bursting for the hydraulic cylinder (27) arranged within the housing member (12). Through a joint (38, 40) and self-aligning, the piston (35) acts upon the lever (18) which is supported coaxially to the ring (14). The lever (18) comprises a ratchet element (17) being supported at the lever (18) by a semisperical pressure member (20). The power wrench can be submitted to extremely high hydraulic pressures without a danger to the environment.

Abstract: A power wrench operated with a pressure medium comprises a wrench head casing (10) which is engaged by a piston-cylinder unit (28,29). The other end of the piston-cylinder unit (28,29) is pressing against a support element (27) guided on a guideway (22) of the wrench head casing (10). The outer end (28) of the support element is applied to a stationary abutment. Upon rotating the wrench head (10) the ring (11) retaining the bolt or screw head is entrained by a ratchet (15) only in one sense of rotation, while the wrench head casing (10) is returned idly without entrainment of ring (11) in the other sense of rotation.

Abstract: This power wrench includes a wrench head that rotatably supports a ring having a non-circular internal profile. A ratchet device moves the ring only in one direction of rotation with respect to the wrench head. The wrench head has an internal extension and a support element is coaxially pivotally attached to the wrench head. A piston cylinder unit, including a piston and a piston rod is provided. The first end of the piston cylinder unit is rigidly connected to the integral extension of the wrench head and the second end of the unit is in contact with the support element. The distance between the center of the wrench head and the first end of the piston cylinder unit is about the same as the distance between the center of the wrench head and the second end of the unit. One end of the piston rod is flexibly held at the piston and the other end is flexibly held at the support element.

Abstract: This disclosure relates to a tool for rotating elements, such as nuts, bolts, screws or like fasteners, and includes a ring having ratchet teeth, the ring being driven by a lever, a pawl carried by the lever for engaging the ratchet teeth, a flexible tension-applying member in at least partial surrounding relationship to the ring, means for supporting the pawl, and the tension-applying member being disposed between the supporting means and the lever whereby upon movement of the lever in a first direction the pawl rotates the ring through the engagement of a tooth of the ring and the tension-applying member deforms slightly to frictionally grip the ring.

Abstract: The sun and planet gear transmission mechanism comprises a power input shaft and at least two successive gear steps including a first gear step and a second gear step disposed within a gear casing. Each gear step includes a sun gear and at least one planet gear. The sun gear of the first gear step is connected to the power input shaft. The power input shaft is axially displaceable so that the sun gear may be disengaged with the appertaining planet gear in the first gear step. Coupling means located at an adjacent gear step is effective to engage the sun gear of the first gear step when said sun gear is disengaged from said planet gear in the first gear step.