GB821943A - Improvements in or relating to automatic screw drivers - Google Patents

Abstract

821,943. Screwing-up screws. SCHMITT, H. Dec. 6, 1955 [Dec. 6, 1954], No. 34966/55. Class 83 (3). An automatic screw-driving device comprises guides for centring the screw-shank. In operation, with the casing 5 secured by the bayonet joint 6 to the motor 4 and with the motor rotating the screw-driver 1 and bit 32, a screw 33 is inserted manually or from a magazine through a slot in a sleeve 22. A sleeve 8 is then drawn rearwardly by a hand-grip 10 until pins 11 on the grip meet the ends of slots 12 in the casing. The sleeve 8 carries with it the sleeve 22 containing balls 35 which grip the screw as it abuts the bit 32. As the screw is gripped, the movement of the sleeve 22 is checked, but the sleeve 8 continues its movement, thus compressing a spring 28 and spring-pressed pins on a sleeve 17 engage behind a collar 15 to retain the grip in its upper position. The screw is then driven into the work. As the screw advances, a sleeve 38 is pushed back against a spring 42 until the balls 35 enter an enlargement 38b therein and release the screw. As the casing 5 moves towards the work the retaining pins are engaged by a collar 29 on the sleeve 22 and are released, thus also releasing the hand-grip and sleeve 8. A spring- pressed ball, in the sleeve 22, assists in guiding the screw-head between the balls 35. Instead of balls 35, rollers may be provided. The sleeve 38, Fig. 6, has three sets of recesses 49a-49c, 50a-50c and 51a-51c engageable by the balls 35 so that, by indexing the sleeve round by a pin 41, screw shanks of different sizes can be gripped. For screws of different lengths different bits 32 are screwed into the end of the screw-driver 1.