Device for fastening and loosening threaded members

A device for fastening and loosening threaded members comprising:

• a motor rotatable in the one direction,
• a drive bevel gear coupled to the motor,
• a pair of driven bevel gears arranged as opposed to each other in orthogonal relation to the axis of the drive bevel gear and meshing with the drive bevel gear,
• an output shaft rotatably extending through the driven bevel gears and having a guide bore and cutouts formed in it,
• means for selectively engaging one of the pair of driven bevel gears with the output shaft to rotate the shaft with the engaged gear or disengaging the gear from the shaft, the engaging means comprising:
• a spool having a circumferential groove in its outer periphery and slidably disposed in the guide bore of the output shaft,
• balls rollably fitting in the cutouts of the output shaft and engageable in the circumferential groove of the spook, the balls projecting beyond the output shaft so as to be engageable with either of the driven bevel gears,
• a spool guide formed with an axial groove and held to the housing,
• a spool holder provided with a projection having a pin and slidably fitting in the groove of the spool guide, the spool holder being retained in the spool guide so as not to be rotatable relative to the spool guide,
• a tubular change drum rotatably fitting around the spool guide and formed with a slanting groove having the pin of the spool holder slidably fitted therein, and
• a change grip attached to one end of the change drum,
• a planetary gear mechanism coupled to the output shaft, and
• a socket mechanism coupled to the planetary gear mechanism for engaging the threaded member,
• the engaging means being operable to subject the torque of the motor to a changeover to forward rotation or reverse rotation by selectively engaging one of the driven bevel gears with the output shaft.