GB826889A - Archimedean-screw hand brace for drilling and the like - Google Patents

Abstract

826,889. Hand-drills. ISSARTEL, R. A. M. Jan. 3, 1958 [Jan. 5, 1957], No. 366/58. Class 83 (3). [Also in Groups XXIII and XXIV] An archimedean hand-drill comprises an archimedean screw 2 engaged by a ball 21 carried by a ring 15, which may be clutched to a collar 9 on the driving handle 5, a return spring 7 acting on the end of the screw which is guided in the handle, and a spring 22 urging the ring into driving engagement with the collar. The other polygonal end 23 of the screw engages the socket end of a drill, wrench or screwdriver (not shown). A knurled sleeve 24 in which the screw rotates in balls 25, may be gripped to facilitate guidance of the tool. A pair of diametrically opposed balls 21 in passages 17 in the ring 15 are held in the flutes of the screw by an outer ring 16 within a casing 14 secured to the collar 9 by a screw 13. Forward movements of the handle 5 engage at least two pins 19 on the ring 15 in two of a circular row of holes 12 in the collar, thus clutching the ring to the handle and rotating the screw. During return movements of the handle, effected by the spring 7, the pins 19 move out of the pockets 12, against the action of spring 22, freeing the ring for rotation on the stationary screw. In a modification, the screw 26, Fig. 6, is double-handed, one or, as illustrated, a pair of flutes of each hand being provided. Two pairs of flute-engaging balls 38a, 38b, Fig. 18, are provided, operative in opposite pairs, the inoperative pair 38b entering escape pockets 46 in the outer ring 28, which may be rotated on the inner ring 27 to change the setting of the balls. An extension 40 of the ring facilitates this rotation, and at least one ball 44 in a passage 43 in the outer ring is pressed inwardly by a spring 45 to engage index pockets 39, Fig. 17 (not shown), in the surface of the inner ring. A pair of guide-balls 42, Fig. 16, in passages in the ring 27, remain in engagement with the flutes and, located at the junction of the crossing-flutes during rotation of the outer ring in an operation to reverse the direction of rotation of the screw, prevent rotation of the inner ring during this operation, and may proceed along flutes of either hand, as decided by the operative balls 38a or 38b. In Fig. 6, the balls 42, which are phased at 45 degrees from the balls 38a, 38b, are on the level of the section 16-16.