Frishauf, Holtz, Goodman, Langer & Chick
Pneumatic torque impulse tool
 A pneumatically powered torque impulse delivering tool for screw joint tightening comprises a housing (10) with a forward impulse chamber (11) enclosing a hydraulic impulse generator (15), a motor chamber (12) disposed rearwardly of the impulse chamber (11) and including a vane type air motor (19), and air inlet and outlet passages (26, 27) located at the rear end of the housing (10). The motor cylinder (20) is provided with radial air communication openings (37a,b, 38a,b, 39a,b) and outer grooves (37c,d, 38c,d, 39c,d) forming passages for connecting the openings (37a,b, 38a,b, 39a,b) to the air inlet and outlet passages (26, 27). Two pairs of openings (37a,b, 38a,b) are alternatively connected to the air inlet and outlet openings (26, 27) via rearwardly extending grooves (37c,d, 38c,d) and a reverse valve (31), whereas a third pair of openings (39a,b) permanently act as outlet openings and communicate with the impulse chamber (11) via forwardly extending grooves (39c,d), and at least one groove (41a,b) extending over the entire length of the cylinder (20) without coinciding with any one of the air communication openings (37a,b, 38a,b, 39a,b) and arranged to connect the impulse chamber (11) to the outlet passage (27). 
Atlas Copco Tools
B
B25B
inventional
Lars M.
Peterson