Patent GB-282817-A (GB)
Title: Process and machine for making integral securing-dies or screw-plates
IPC: B23P15/48
Filed: 1927-12-29
Abstract: 282,817. Ziegler, A. Dec. 31, 1926, [Convention date]. Screwing-dies.-A machine for making integral screwing dies or screw-plates from circular blanks comprises a work-carrying headstock 6 and a vertical tool-turret 4 carried by a common bed 41. The tool turret has eight stations, six of which carry tools rotated by a central gear wheel 23 on a belt driven sleeve 21, while one of the others carries a sliding sleeve 34 for guiding a non- rotating tap, and the remaining one carries a file which is reciprocated, together with the turret for finishing off the cutting edges of the die. The turret is mounted on a compound slide 2, 3, and is angularly adjustable on a turntable 7, adjustment to and from the headstock along the slide 3 being effected by a hand-lever 29 carrying a pinion 31 engaging a rack on the turret and transverse adjustment being effected by means of a handoperated screwed spindle having a graduated, collar to facilitate setting. The blank 8 is held in a chuck 10 controlled by a hand-lever 12, two index plates 14, 17 being provided for positioning the blank when drilling it, and filing the cutting edges respectively, and the blank being rotated by pulleys 13 during the tapping of the central hole. In operation, the central hole 24, Fig. 6, is centred, drilled and tapped in the blank, after which the clearance holes 15 are drilled and the blank is gashed at 18 by an end mill to form the cutting edges, the gashing being performed in two stages, 18<1> and 18<2>, so that the final stage shall leave sharp cutting edges. The first cut 18<1> just penetrates to the threaded opening 24 while the second cut 18<2> completes the gash and the hole is retapped after each cut to remove burns. The clamping-screw holes 16 are then drilled, and the faces of the die are next finished by fine cutters or grinders. At the last station the turret is anglarly adjusted, and a flat or round file is reciprocated by the hand-lever 29 to form the cutting edges 33, the angle of which is determined by setting the file in its holder VIII, Fig. 2, by means of graduations on the holder according to the kind of metal which the die is designed to cut. The file is held in a holder slotted at 37, Fig. 4, and is adjuistably clamped by a screw 38. A star shaped head 35 on the spindle 20, which slides the turret, carries adjustable stops 26 which co-operate with a boss on the turntable 7 to limit the depth of feed by the hand-lever 29, and the turret is indexed by a lever 27 oscillated by a handle 27' against a spring 27<2> to registering slots in the turret and its surrounding sleeve. The turntable is angularly adjusted by means of graduations, and is set in the zero position by means of a stop screw 40. The tool-spindles are set laterally in relation to the blank axis by the band-operated screw 43, and its graduated collar, or an adjustable stop screw 44, while a second stop screw 47, operated by a hand-lever 46, has two notches engaged by a spring pressed ball to determine the depth of the two gashing operations 18<1> and 18<2>. An adjustable stop is also provided on the slide 2 to determine the angular setting of the file when forming the cutting edges 33, and a locking device, released bv a hand-lever, is provided for maintaining the slide 2 in any laterally adjusted position. The head 25 serves for rotating the turret by hand, and the tool-spindles and the work-spindle 11 are mounted in ball bearings.