Patent GB-754504-A (GB)
Title: Improvements in or relating to variable-speed gears
Inventor: GRUENBAUM HEINRICH
IPC: F16H37/00
Filed: 1954-08-18
Abstract: 754,504. Variable speed gearing. STAHLKONTOR WESER GES. Aug. 18, 1954, No. 24039/54. Class 80(2) [Also in Groups XVI and XXXV] Variable ratio gearing, particular for driving apparatus winding paper, wire, textiies, ropes &c. into coils, comprises a series of pairs of gears provided with free wheels engaging automatically and successively when the speed of rotation of an output shaft has reached that ratio to the speed of rotation of an input shaft which corresponds to the speed reduction' ratio of the gears concerned. In one form, input shafts 2, 3, Fig. 1, are driven by electric motors 5, 6 and carry fast gears 7, 8; 9. 10 meshing gears 11, 13; 12, 14, each clutchable to an output shaft 4 by a friction freewheel device. Each . gear 11, &c., it rotatable on the shaft 4 and abuts a disc 16 also rotatable on the shaft, balls 17 lying in conical recesses in the discs and gears. Adjacent to the discs 16 and fast on the output shaft 4 are friction discs 15. Pins 21 pass freely through the discs 15 and abut at one end against the gears 12, &c., and at the other against the discs 16. Pins 18 on the gears 12, &c., contact pins 19 on the discs 16 to prevent relative rotation in one direction between each gear and its disc 16. Relative rotation between a gear 11, &c., and its disc 16 causes the balls 17 to ride up the sides of the conical recesses containing them, axially separating the disc and gear and frictionally engaging the disc 16 with the disc 15 fast on the output shaft 4. The gear 11. &c.. can then drive the output shaft. The gear 11 and its disc 16 are pressed lightly into engagement with the associated disc 15 by a spring 20. A-t the commencement of a winding operation, both motors 5, 6 are set in motion. and the gears 7, 11 transmit drive to the output shaft 4. due to the light frictional engagement between the discs 15. 16 caused by the spring 20. As soon as the load is taken up. the balls 17 ride up their conical recesses in the gear 11 and disc 16, and the discs 15, 16 are more firmly urged into engagement. The motor 5 now drives the output shaft 4, the motor 6 runs free and the gears 12, 13, 14 rotate freely on the output shaft. As the diameter of the wound coil increases, so does the torque, and the speed of the output shaft 4 and motor 5 gradually decreases, the speed of the motor 6, running free. remaining constant. When the speed of the output shaft 4 has decreased to such an extent that it is the same as the speed of the gear 12, driven through the gear 9 by the motor 6, the balls 17 associated with the gear 12 ride up in their conical recesses. This axially separates the corresponding disc 16 from the gear 12 and moves it axially into engagement with its disc 15 fast on the output shaft. and simultaneously moves the gear 12 slightly to the right so that, through the pins 21, it separates the discs 15, 16 associated with the gear 11, which accordingly rotates freely on the output shaft 4. The motor 6 now drives the output shaft 4 through the gears 9, 12, and the motor 5 runs free. As the size of the wound coil increases further, the process is further repeated, first the gear 13 being clutched to the output shaft 4 and finally the gear 14. The successive ratios are arranged to form a geometric progression. More than four speed ratios can be employed, and the two electric motors 5, 6 can be replaced by means permitting slipping, such as, friction clutches. iron powder clutches, eddy current clutches, turbo-couplings, &c. In a modified form of gearing, a driving shaft 23, Fig. 2, carries a gear 25 clutched thereto by a multidisc clutch 36 and a series of gears 26 ... 33 of decreasing diameter rotatable on the shaft but frictionally engaging discs 34 splined to the shaft. The gears 26 ... 33 are pushed into engagement with the friction discs 34, and the clutch 36 is engaged, by the pressure of fluid admitted to a cylinder 37 containing an annular piston 38 urging the gear, &c. axially to the right of the Figure. The gear 25 meshes a gear 42 fast on a driven shaft 24, and the gears 26 ... 33 mesh gears 43 ... 50 mounted on the driven shaft by friction roller freewheels 51. At the 'start of a winding operation, the gear 25 drives the gear 42, and as the diameter of the wound coil increases, and hence the torque required increases, so the multidisc clutch 36 slips. Eventually the degree of slip increases to such an extent that the ratio of the speeds between the shafts 23, 24 is the same as the ratio between the gears 26, 43. The corresponding free wheel 51 then engages, and torque is transmitted not only through the slipping clutch 36. but also through the train 26, 43. With further increase in torque, as the diameter of the wound coil increases still further, the gear 26 begins to slip relatively to its adjacent friction discs 34, until the train 27. 44 is brought in on the engagement of the appropriate free wheel 51. The process is repeated until all the gears are transmitting the maximum torque, slipping taking place at all the friction surfaces. The continual slipping of the friction surfaces generates a substantial quantity of heat, which is dissipated by mounting the gear in a two part housing 22. Fig. 3, having spiral tubes 53 through which cooling water is passed. Oil can be supplied through a screw closed hole 59 and drained off through a screw closed hole 60. The slipping means can be engaged by spring or weight means, or by compressed air, instead of by the hydraulic means shown. As further modifications. the gears may be divided into groups within which mutual disengagement does not take place, while the individual groups are disengaged successively. The gears 25 ... 33 can also be arranged on different shafts grouped around the shaft 24, with a central driving shaft. Further, the individual gears may be arranged not only in parallel, as shown, but also partially in series.