Patent GB-1100816-A (GB)
Title: Tension controlling mechanism for textile machines
IPC: B65H59/24
Filed: 1966-09-05
Abstract: 1,100,816. Yarn-tensioning devices. THERMIGUIDES S.A. 5 Sept., 1966 [15 Sept., 1965], No. 39533/66. Heading D1D. In a device for controlling the tension in a yarn in which the yarn passes between a fixed member and a movable member spring-urged towards the fixed member, and a magnet, connected to a pivoted lever movable according to tension-changes in the yarn, acts to modify the pressure applied by the movable member on the yarn, the magnet is arranged to travel during its movement in parallel relationship to a magnetic member in such a way that the flux between the magnet and the surface does not exert on the magnet any force tending to impair the sensitivity of the device by causing the lever to pivot. In Fig. 1, the yarn travels through a guide 7 between fixed and movable members 2, 2a, through an eyelet 9 on a lever pivoted at 11 and a guide 14. The movable member 2a is of magnetic material and is urged towards the fixed member on a spindle 3 by a spring 4 the force exerted by which is adjustable by a nut 5. The lever is urged in the direction of the arrow by a spring 15, and is attached to a magnet 12 arranged slightly above the level of the movable member. When the yarn is adequately tensioned, the lever swings oppositely to the arrow, and the magnet attract it against the pressure of spring 4 away from the fixed member, so that no additional tension is imparted to the yarn. When the tension is inadequate, the lever is swung by the spring 15 to move the magnet to a greater or less extent away from the movable member to modify correspondingly the effect of the spring 4. During its movement, the magnet travels above an arcuate magnetic strip, the flux between the two exerting no lateral force on the magnet which would tend to affect the pivoting of the lever. The tension that can be added to the thread can be varied by adjusting the nut 5 and by changing the spring or replacing it with a mechanical, electrical or pneumatic device, the force exerted by which can be varied. To limit the upward movement of the movable member, the upper part of the spindle 3 which is encircled by the spring 4, is constituted by a nut adjustably received on a threaded part of the spindle, the upper part of the nut being threaded to receive the nut 5 (Fig. 4, not shown). In Fig. 2, the magnet 2 and lever 6 are connected together and rotatably mounted on the spindle 3, while the spring 4 is replaced by an asymmetric plate-spring 4a, so arranged that, under the influence of the magnet, that part of the rim of the movable member near the yarnpath will lift more readily than will the more remote part, and the magnet will move over the readily-liftable part when the tension is adequate. The arcuate path over which the magnet moves is constituted by a concentric rim of the movable member; alternatively, it can be constituted by a magnetic part provided on the rim which widens progressively in a radial direction, surrounded by a fixed magnetic member also widening radially but in the opposite direction, so that the radial width of the two parts taken together is constant (Fig. 8, not shown). The cooperating members 2, 2a can be bent upwardly so that their rims are spaced apart to provide room for the magnet to move between them (Fig. 5, not shown).