Patent GB-1051736-A (GB)
IPC: B65H59/38
Abstract: 1,051,736. Winding yarns. I. S. ROBERTS. June 5, 1963 [June 6, 1962], No. 22291/63. Headings DID and D1J. The invention relates to a machine for winding yarn fed thereto at constant speed, the rotational speed of the yarn package being varied by friction gearing to maintain the yarn take-up speed of the package equal to the speed of the yarn supply, there being means for reducing the tension in the yarn as the package diameter increases. As shown in Figs. 1, 3 (not shown) and 4 the friction gearing comprises a friction disc 32 driven by a motor M and a friction disc 34 that is used to drive the package 19, the disc 32 driving the disc 34 via a friction wheel 40. The friction wheel 40 is carried by a bracket 49 that is slidable on a bar 44 carried by a U-shaped frame 46, the frame 46 being pivoted at 47. By rocking the frame 46 the axis of the friction wheel 40 can be moved to either side of a common plane A-A, Fig. 4, passing through the axes of the two discs 32, 34. Yarn delivered by a constant feed mechanism 10, Fig. 1, passes under a dancer roll 11 and thence via a traversing device 18 onto a package 19, the dance roll 11 being part of a lever mechanism 12, 43, 58 that is used to vary the setting of the frame 46 and hence the position of the friction wheel 40 relatively to the plane A-A. Speed control. If the package 19 rotates too fast the dancer roll 11 rises and the levers 12, 43, 58 move in a manner permitting the friction wheel 40 to move to a point below the plane A-A in Fig. 4 whereby the friction wheel 40 tends to follow a spiral path on the disc 32 and so moves to the right. This decreases the speed ratio between the discs 32, 34 and the speed of the package 19 falls. If the package 19 rotates too slow the dancer roll 11 falls and the levers 12, 43, 58 rock the friction wheel 40 to a point above the plane A-A whereby the friction wheel 40 tends to follow a spiral path on the disc 34 and so moves to the left. This increases the speed ratio between the discs 32. 34 and the speed of the package 19 increases. The take-up speed is then kept constant. Tension. During formation of the package 19 it is desirable to provide a predetermined initial tension in the yarn which gradually decreases during the winding operation. As shown, Fig. 1, the initial tension is set by a spring 61 that tends to rock the dancer roll 11 downwardly. Since the diameter of the package 19 gradually increases its speed must be gradually reduced and the friction wheel 40 thus moves gradually to the right as viewed in Fig. 4. The downward thrust of the discs 32 and 34 on the friction wheel 40, being a function of torque, increases as the friction wheel 40 moves to the right. Since this downward thrust on the friction wheel 40 acts through the linkage 43 its effect is to counter the force of the spring 61 and hence the net reaction force at the dancer roll 11, which determines the tension in the yarn, is decreased. Modified constructions. In Fig. 6 (not shown) the rotational axes of the friction discs 132, 134 lie in a common plane B-B, the friction wheel 140 being carried by brackets 149 that are normal to the plane B-B but are slidable along a bar 144 that is inclined to the plane B-B. This modified arrangement is stated to give inherent damping. The embodiment illustrated in Fig. 4 may be damped by fitting a stationary piston 70 on the bar 44 and enclosing it in a cylinder forming part of the assembly sliding on the bar 44, the cylinder being filled with fluid that is metered through a clearance between the piston and the cylinder. The bar 44 may be associated with means whereby it can be inclined to the plane A-A to vary the speed ratio between the discs. Starting. The machine is started by manually raising the dancer roll arm 12 from the inclined position show in broken lines in Fig. 1 toward a horizontal position whereby the outer end of lever 50 disengages a contact of a switch S to start the constant speed motor M. The motor M drives the disc 32 which, through the friction wheel 40, rotates the disc 34 which in turn acuates the winding spindle 16.