Patent GB-974000-A (GB)
Title: Torque controlled strand tensioning system and method
IPC: D01H13/16
Filed: 1960-12-06
Abstract: 974,000. Variable-speed gearing. WHITIN MACHINE WORKS. Dec. 6, 1960 [Dec. 11, 1959], No. 41869/60. Heading F2D. [Also in Divisions D1 and H2] The winding-speed and tension are controlled in a roving frame having rotating flyers for winding a roving on to rotating bobbins, by applying to the flyers or bobbins a control torque and sensing the torque transmitted from the bobbins to the flyers through the strands and varying the relative speeds of the flyers and bobbins in response to any tendency for the transmitted torque so sensed to vary relatively to the control torque. The tension may thus be kept constant by maintaining the control torque constant; or the tension may be varied during a winding cycle according to a predetermined programme by suitably changing the control torque. Further, the spacing of the times of roving laid on the bobbins may be kept constant or varied by changing the speed at which the flyers and the bobbins are traversed relatively to one another according to variations on the said rotational speeds. General arrangement, Fig. 1.-Rovings pass from rollers D driven by a shaft 50 to flyers 22 on spindles 21 each driven from a shaft 20 and bobbins 31 each driven from a shaft 37. The main drive is a shaft 10 driven at constant speed by motor 12; shafts 50 and 20 are geared directly to shaft 10, but bobbin shaft 37 is driven at variable speed by the output gear 42 of a compound differential 40 of which the input is derived from constant speed shaft 10 and, through a gear 121, from variable-speed shaft 124. The latter is the output shaft of a "variator " 125 of which the input shaft 132 is connected through a torque-sensing device 131 to a shaft 130 driven from constant-speed shaft 50 through a chain and sprockets. Changes in torque between flyers and bobbin cause the device 131 to adjust the output of the variator to change the speed of shaft 124 and hence, in the form described, of the bobbins to restore the desired tension. The senser may be such as to keep the winding tension constant during a run, or to vary it according to a programme, and a second " variator " may vary the " lay " according to the changes in bobbin speed. The " variator " and senser may be used in conjunction with a conventional double-cone arrangement, and the senser may be interposed in shaft 124. The " variator " 125 and torque-senser 131, Fig. 2.-The variator comprises input and output shafts 132, 124 connected by a belt 137 over expansible pulleys 135, 136. The senser comprises a differential gear assembly in a housing 133; the equal internal torques exerted by the oppositely rotating shafts 132, 130 are balanced by a torque of twice the value of each internal torque applied externally by a weight B on a cord wrapped around a drum 152. When the internal and external torques get out of balance the housing is rotated; this rotation is transmitted through gears 145, 144 to a shaft 143 with oppositely-threaded portions at 142 whereby the cones of the pulleys are moved oppositely to change the drive transmitted to shaft 124 to restore the balance. The speed of shaft 130 corresponds to the starting bobbin speed, and the initial position of shaft 143 is such that when output shaft 124 is driven it immediately establishes the desired tension. The weight B is then at its lowest position, and is gradually wound up as winding proceeds. A brake 177 is applied to the housing to restrain the weight when the machine is not operating, means being provided to keep the brake on until the driving-motor reaches full speed at starting. To reset the parts after a cycle, a low-speed auxiliary motor 172 is connected to shaft 130 by chain and sprockets, the sprockets at 165 and 157 embodying one-way drives, Figs. 8, 9, 10, not shown, so that when shaft 130 is driven by sprocket 165 it will not drive sprocket 157 and vice versa. To relieve shaft 143 and gear 144 of the full effect of weight B during resetting, a gear 234 is connected to shaft 132 by a one-way drive, Fig. 11, not shown, so as to be capable of driving, but not being driven by, shaft 132; this gear meshes with gear 232 operatively connected to gear 145 on the housing. As shaft 130 slowly rotates to reset the weight, there is no appreciable torque between it and shaft 132 and the housing is free to be rotated by the descent of weight B, but only at a rate controlled by the speed of shaft 132; the winding tension may be adjusted by changing the weight B; drum 152 may be non- cylindrical to vary the winding tension as the winding operation proceeds; also an additional weight on an extension of the drum may be used to compensate for friction. The weight may be replaced by-springs, hydraulic or pneumatic means. Traverse arrangements. Fig. 1.-Shaft 37 is carried in bobbin-supporting brackets carried by the bolster rail which is raised and lowered through an arcuate rack 76 meshing with gear 75 on shaft 74 geared to shaft 61 carrying bevels 57, 58 moved by a reversing lever 80 alternately into engagement with a bevel on a shaft 55. Lever 80 is moved to and fro by an eccentric 81 on shaft 51, which is rotated through half a revolution at the end of each stroke of the traverse. For this purpose, shaft 51 carries a mutilated pinion 91 in engagement with a constantly rotating bevel 92 on constant-speed shaft 50. Shaft 51 is biased to rotate, but is restrained by one of two arms 83, 84 engaging jaws 85, 86 on a shaft 90 which is raised and lowered with the bolster rail. As the jaws move clear of the restraining arm, the shaft 51 rotates to bring teeth on bevel 91 into engagement with bevel 92 so that shaft 51 is rotated through half a revolution. The opposite arm now engages the jaws and a second gap in the teeth of pinion 91 comes opposite the teeth of bevel 92. As shaft 51 rotates, it moves a rack 102 to rotate shaft 90 through a gear 105 keyed thereon, and the jaws 85, 86 which are on oppositely-threaded portions of the shaft are thus moved together with each stroke to shorten the traverse. A handle 106 is provided for re-setting the jaws. To correlate the traverse with the winding tension, shaft 55 is driven from the output shaft of a second variator 245 which may be of the same design as 125 and have its output similarly adjusted by the rotation of shaft 143. To vary the build of the package the variators may be controlled together, but in adjustable relation to one another by dividing shaft 143 into two sections each serving one variator, a change gear assembly being provided between the two sections.