Abstract: A hydraulic torque impulse generator comprises a motor rotated drive member (16) including a fluid chamber (18) into which the rear end portion (19) of an output spindle (21) extends to receive torque impulses generated in said fluid chamber (18). The rear end portion (19) of the output spindle (21) carries a radially sliding vane (23) for cooperation with the fluid chamber (18) such that a high pressure compartment and a low pressure compartment are accomplished during a limited portion of the relative rotation between the drive member (16) and the output spindle (21). A seal barrier (43-50) around the output spindle (21) prevents fluid leakage from the fluid chamber (18). The seal barrier comprises a clearance seal (43) between the fluid chamber end wall (38) and a low pressure area which is sealed off to the atmosphere by low pressure seal rings (47, 48, 60).

Abstract: A pneumatic power tool for tightening screw joints includes a primary motor 11 for a high speed running down sequence, a secondary motor 12 for a high torque final tightening sequence, a coupling gearing 18 providing a high ratio gearing for the secondary motor 12, a gearing of a substantially lower ratio for the primary motor 11 and a one-way clutch 30 by which the secondary motor 12 is automatically engaged at decreasing tightening speed. An air supply valve 33 substantially reduces the air consumption of the tool by keeping the air supply to the secondary motor 12 shut off until a certain degree of tightness in the joint is obtained, after which the valve 33 is opened and the secondary motor 12 is energized.

Abstract: A pneumatic power tool for tightening screw joints comprises a primary motor 11 for the high speed running down sequence and a secondary motor 12 for the high torque final tightening sequence. The tool includes a coupling gearing 18 providing a high ratio gearing for the secondary motor 12, a gearing of a substantially lower ratio for the primary motor 11 and a one-way clutch 30 by which the secondary motor 12 is automatically engaged at decreasing tightening speed. An air supply valve 33 is employed to substantially reduce the air consumption of the tool by keeping the air supply to the secondary motor 12 shut until a certain degree of tightness in the joint is obtained which by the supply valve 33 is experienced as an increased back pressure from the primary motor 11. At a back pressure corresponding to the predetermined certain degree of tightness in the joint the valve 33 is opened and the secondary motor 12 is energized.

Abstract: A pneumatic power tool for tightening screw joints includes a primary motor 11 for the high speed running down sequence and a secondary motor 12 for the high torque final tightening sequence. The tool includes a coupling gearing 18 providing a high ratio gearing for the secondary motor 12, a gearing of a substantially lower ratio for the primary motor 11 and a one-way clutch 30 by which the secondary motor 12 is automatically engaged at decreasing tightening speed. An air supply valve 33 is employed to substantially reduce the air consumption of the tool by keeping the air supply to the secondary motor 12 shut off until a certain degree of tightness in the joint is obtained, after the valve 33 is opened and the secondary motor 12 is energized.A reduction gearing 19 is supported in a casing 90 which is rotatively connected to the tool housing 10 and provided with a laterally extending torque reaction bar 92.