Patent GB-626034-A (GB)
Title: Improvements in web-winding devices
IPC: B65H23/198
Filed: 1947-08-05
Abstract: 626,034. Winding webs. OIL GEAR CO. Aug. 5, 1947, No. 21256. Convention date, July 3, 1939. [Class 100 (i)] [Also in Group XXIX] A hydraulic apparatus, which is especially applicable for winding a web 2, Fig. 1, delivered by a machine 4 upon a spindle 1 is constructed with a variable displacement hydraulic motor 10, geared to the spindle 1, the displacement block 11 of which is adapted to be moved by a piston 12 to the left to increase the displacement and by a piston 14 to decrease it, The motor 10 is controlled so as to vary with the speed of the web, and so as to vary the torque as the roll increases in diameter, and compensation is provided for frictional losses. The motor is driven by liquid delivered by a pump 17 which is geared to the machine 4 and acts as a metering pump since it controls the rate at which liquid is discharged from the motor 10. A booster pump 16 driven at a constant speed independently of the machine 1 also assists to drive the motor 10, and excess liquid is drained by a tension control valve 20 comprising pistons 60, 61, and a lower valve 58 connected to the supply pipe 18 of the motor. At a variable pressure controlled by an adjustable spring 64, the valve 58 opens to limit the pressure in pipe 18. If it is desired to accelerate the web by increasing the pressure of the driving fluid a valve 69 may be opened by a lever 71 to connect pressure fluid delivered by a gear pump 23 to a pipe 68 arranged above the piston 61, and to connect a pipe 67 below the piston to drain, and thus increase the pressure of the driving fluid by increasing the pressure required to actuate control valve 20. The machine 4 has a starting handle 8 connected by a link to a valve 33 shown closed in Fig. 1. The valve is moved to the right to start the motor 10 and the inlet to pump 17 is then completed via pipe 42, valve ports 38, 39, pipe 43, choke valve 44 and inlet pipe 45. The displacement of the motor 10 is then dependent upon the pressure in pipe 45 which is connected via pipe 85 to the cylinder 15 of piston 14. The opposing cylinder 13 is connected to a pipe 25 supplied by the gear pump 23 at constant pressure. To adjust the drive of motor 10 for varying speeds of web, the tension valve 20 is connected by pipes 77, 78 to the pipes 43, 45 which are connected by a resistance valve 44. Since variations of pressure in pipe 43 are transmitted slowly to pipe 45, the momentary pressure differential causes variation of pressure in the inlet pipe 18 and so varies the torque of the motor. This is due to the effect of the pressure differential in pipes 77, 78 upon the tension control valve 20.. The torque of the motor 10 increases as the roll 3 increases in diameter, due to automatic slagging of the motor with consequent drop of pressure in the pipes 85, 45, and therefore in cylinder 15 which causes displacement of the block 11 to the left and increase in torque of the motor with consequent diminished speed. To compensate for friction losses, a small pump 87 driven in unison with motor 10 is driven by liquid supplied by a pipe 89 connected to intake side of pump 17, and its outlet to low pressure pipe 27 which supplies pump 16. By extracting from the return side of the circuit, piston 14 moves to the left, and the motor displacement is increased. The choke valve 44 may be replaced by a fluidcontrolled valve which is arranged to increase the resistance to flow between pipes 43, 45, upon increase of web speed, and so automatically increase the action of the control valve 20 in raising the pressure in pipe 18 with increase torque of the motor. In a modification, Fig. 6, for increasing gradually the tension on roll 3 as it increases in diameter, the tension control valve 20 is fitted with control pipes 77b, 78b, similar to 77, 78, Fig. 1, but supplied with pressure from gear pump 23 via a pipe 25, choke valve 105. The pipe 28b is supplied with liquid via a spring-controlled valve 103, the spring of which engages the stem of piston 12, so that as piston 12 moves to left as the roll 3 increases in diameter, the resistance of valve 20 will be reduced and the tension on the web reduced gradually. By arranging the valve 103 in connection with the piston 14, the tension can be increased gradually instead of reduced gradually. In a further modification, the hand-operated valve 69 may be replaced by a valve which automatically produces increase of torque of the motor 10 in response to acceleration of the web, and in another modification the torque of motor 10 may be increased during acceleration and decreased during deceleration by varying the resistance of the tension control 'valve 20 in response to a mass-actuated governor which is driven in unison with the motor 10.