Schlagschrauber mit drehmomentabhaengiger Abschaltung des insbesondere elektromotorischen Antriebs

916,554. Slip couplings. FEIN, H. W., [trading as FEIN, C. & E. [Firm of]]. May 27, 1960 [June 20, 1959], No. 18830/60. Class 80 (2). [Also in Group XXII] A power - operated rotary impact tool for tightening nuts or screws comprises a tool-holder and anvil member 9 which cooperates with a hammer member on one or other of third and fourth members 12, 11 which together form a striker member and are axially and rotatably mounted in the tool housing 4, means 13 connecting the third member 12 and a drive means 5 and adapted to tend to withdraw the member axially away from the anvil during operation, a force-exerting means 14 to urge the hammer member into engagement with the anvil, the fourth member 11 being axially and rotatably movable relatively to the third member and co-operating therewith by means 15 which rotates the fourth member relatively to the third member to urge the fourth member in a predetermined axial direction against the action of spring means 31 relative to the third member and housing when the torque impact exceeds a predetermined amount to operate switch means 35 to switch off the drive means. The means 15 comprise oblique engaging teeth on the members 11, 12. The switch means 35 can be adjusted by a nut 30. The two sets of teeth can be positioned as in Fig. 4 to give a constant drive, the oblique teeth then being disengaged. In a modification, the oblique teeth are formed on pins 40, 42, Fig. 8, and the third and fourth members 38, 39 are urged together by springs 46, Fig. 7.