Patent GB-1375467-A (GB)
IPC: F16H3/093
Filed: 1972-05-30
Abstract: 1375467 Change-speed gear WERKZEUGMASCHINENKOMBINAT "FRITZ HECKERT" KARL - MARX - STADT VEB 30 May 1972 25231/72 Heading F2D A machine-tool change-speed gear, shown in Fig. 1, as producing eighteen ratios forward and reverse, and in Fig. 2, not shown, twenty-four ratios, but capable of two hundred ratios, comprises a main train of four parallel shafts 2, 3, 4, 7, which can, through a friction clutch 25, selectively directly connect the input and output shafts 2, 7, at, e.g. six, or eight ratios, and an auxiliary gear on parallel shafts 5, 6, which can, through at least one positive selector clutch 34, 37, be selectively interposed between the main train and the final output shaft 7, to provide, e.g. three ranges of ratios, the main gear having wheels which can be selectively clutched thereto by friction clutches, whilst the positive clutches 34 or 37 select ratios in the auxiliary gear. Synchronization is therefore necessary for only these two positive clutches 34, 37 of the auxiliary gear. The input shaft 2 is driven through a clutched reverse gear 40-51 by a motor 9 capable of being mounted in different positions, and optionally of polechanging to increase the number of ratios. The clutches are all electromagnetically engaged, and control may be by punched card, magnetic tape or computer. In Fig. 1, the auxiliary train provides three ranges, high, medium and low, each giving six ratios as follows. High range.-The main gear drives direct from input 2 to output 7, ratios one to six being as follows. First (highest output speed), friction clutch 12, gears 11, 16, 22, friction clutch 23, shaft 4, friction clutch 25, gears 24, 38 and output shaft 7. Second, friction clutch 15, gears 14, 19 shaft 3 to gear 16, then as for first. Third, gears 13 17, friction clutch 18, shaft 3 to gear 16, then as for first and second. Fourth, friction clutch 12, gears 11, 16, shaft 3, gears 20, 26, friction clutch 27, shaft 4, friction clutch 25, and gears 24, 38 to output 7. Fifth, clutch 15, gears 14, 19, shaft 3, then as for fourth. Sixth, gears 13, 17, friction clutch 18, shaft 3, then as for fourth and fifth. Medium range.-The friction clutch 25, used only for direct connection of the main gear to output 7 in the'high range, is released, and replaced by engagement of the friction clutch 31 connecting the main to the auxiliary gear 5, 6, and the auxiliary gear dog clutch 34 on the output shaft 7 is engaged. In the six to seven shift to medium range the dog clutch 34 synchronizes as the output shaft 7 slows down during shift, synchronism being detected by input and output driven tacho-generators 10, 39, controlling a bridge circuit, not described, permitting clutch engagement. The six medium range ratios (seventh to twelfth) follow the six high range ratios above described, as far as the shaft 4, and thereafter pass to output 7 through gears 21, 28, 29, friction clutch 31, shaft 5, gears 32, 33 and dog clutch 34 to output 7. Low range.-The friction clutch 31 is released and the main gear connected to the auxiliary by engagement of a dog clutch 37, whilst dog clutch 34 remains engaged. Ratios thirteen to eighteen again follow the six ratios of the main gear up to shaft 4, then through gears 21, 28, 29, 30, 36, dog clutch 37, shaft 6, gears 35, 32, 33 and dog clutch 34 to output 7. The dog clutch 37 is engaged when the output shaft 7 slows down to synchronism during the twelfth to thirteenth shift, the tacho-generators 10, 39 again detecting synchronism to control clutch engagement. By attaching the drive motor 9 to different shafts (Figs. 3, 4, not shown) the ratio range may be extended to fifty and doubled to one hundred by pole changing. Fig. 2, not shown, provides twenty-four ratios in three ranges of eight. The main gear has an additional meshing pair (63, 68) and friction clutch (69) between the first two shafts to provide the eight main ratios. The auxiliary gear has an additional stepped wheel pair (81, 82) meshing a wheel (86) fast on the second shaft (56), and a wheel (91) clutchable (at 90) to the final output shaft (57). Two dog clutches (84, 90) are used for the medium range, and two dog clutches (84, 92) for the low.