| 摘要 |
1,228,442. Automatic tension control. GOODYEAR TIRE & RUBBER CO. April 8, 1968 [May 8, 1967], No. 16718/68. Heading G3R. A signal dependent on the tension of a moving textile cord or fabric after it has been at least partially heated and tensioned in a treatment zone is compared with a signal corresponding to the desired tension, the magnitude and sign of any difference intermittently controlling the residence time in the treatment zone to correct the tension automatically. In Fig. 1, tyre cord fabric 10 passes continuously from drag rolls 11 through a heat-treating oven 15 to pull rolls 12. Dynamo-electric machines 13, 14 respectively associated with rolls 11, 12 are arranged to produce a desired stretch of the fabric. Tension is detected by an idler roll 41 associated with a load cell 40 controlling a potentiometer 43. Deviations of tension from a desired value determined by the setting of another potentiometer 44 are thus effective to operate a servomotor 33 adjusting a potentiometer 32 to a corresponding position. Potentiometer 32 controls a follow-up servosystem associated with a Ward Leonard set 27, 28 so that chains 22 are adjusted to raise or lower idler rolls 20 thereby increasing or decreasing web transit time in the oven as necessary to restore tension to the desired value. The adjustment is made intermittent by a unit 46 in which a condenser is periodically charged to a voltage corresponding to the magnitude of the deviation and causes operation of a relay 52 and hence motor 33 for periods corresponding to the magnitude of the deviation at intervals corresponding to oven transit time. Idler rolls 25 attached to the other ends of chains 22 move in the opposite direction to rolls 20 so that the total length of travel of the fabric remains constant. Potentiometer 32 is supplied from a tachometer generator 29 so that treatment time is compensated for variations of speed of travel of the fabric. By changing over switches 53a-d servomotor 33 may alternatively be controlled in a follow-up manner by a manually operated potentiometer 36. |
