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Device for equalizing the tension in a filament
US3279670A
United States
- Inventor
Martin Jean Claude - Current Assignee
- Rhodiaceta SA
Worldwide applications
Application US430364A events
1965-02-04
1966-10-18
Application granted
1966-10-18
1983-10-18
Anticipated expiration
Status
Expired - Lifetime
Description
translated from
Oct. 18, 1966 J. c. MARTIN 3,279,670
DEVICE FOR EQUALIZING THE TENSION IN A FILAMENT Filed Feb. 4, 1965 lnvenlur A Home United States Patent 3,279,670 DEVICE FOR EQUALIZING THE TENSION IN A FILAMENT Jean Claude Martin, Lyon, France, assignor to Societe Rhodiaceta, Paris, France, a French body corporate Filed Feb. 4, 1965, Ser. No. 430,364 Claims priority, application France, Feb. 12, 1964, 963,519 6 Claims. (Cl. 226-195) This invention relates to a device for equalizing the tension in travelling yarn, for example during win-ding.
Fluctuations of the tension in a yarn during winding result in irregularities in the product obtained, and many devices are known for equalizing this tension.
For example, there may be employed a supply cylinder rotating at a peripheral velocity higher than the winding speed of the yarn and about which the latter passes. The cylinder thus tends to drive the yarn continuously and to supply it to the winding members almost without tension. This device has the disadvantage that it possesses no means of adjustment.
In another device, the yarn passes round a portion of the periphery of a roller driven at a peripheral velocity higher than the speed at which the yarn is travelling, and a current of air is provided to lift the yarn from the roller. The force exerted by the current of air on the yarn tends to reduce the arc embraced by the yarn on the roller, while increase of the tension in the yarn as it leaves the device tends to increase the arc embraced. The change in the length of the arc embraced produces a change in the frictional forces between the yarn and the roller, which results in a regularisation of the tension in the filament as it leaves the device. This device operates perfectly only with low yarn tensions.
It is an object of the present invention to provide a device for automatically equalizing the tension in a moving yarn, regardless of the variations of tension which occur upstream or downstream of the device.
According to the invention a device for automatically equalizing the tension in a travelling yarn comprises a cylinder adapted to be rotated at a peripheral speed greater than the rate of travel of the yarn and in the same direction, yarn guide means positioned to cause the yarn to travel through at least one arc in contact with the surface of the cylinder and including at least one movable yarn guide mounted so as to be moved by an increase in the tension of the yarn in a direction which increases the length of at least one are over which the yarn makes contact with the cylinder, and return means tending to move the said movable guide in a direction which decreases the length of the said arc.
Preferably, the device comprises two movable yarn guides.
In a preferred embodiment of the/invention the movable yarn guide or guides are each mounted at or towards the end of a bar pivoted about a point between its two ends, and the return means operate on each bar on the other side of the pivot. Advantageously the return means comprises a spring. For example when there are two yarn guides carried on pivoted bars, the return means may comprise a single spring acting on both bars, e.g., a tensioned spring joining the two bars. It may be convenient to use curved bars one on either side of the rotating cylinder, the curvature being suflicient to keep them out of contact with the cylinder. The surface of the guide with which the yarns make contact will usually be such as to reduce friction to a minimum; thus it may be provided by a freely running pulley.
The invention is illustrated in the accompanying drawing, in which,
ice
FIGURE 1 is a diagrammatical lateral view illustrating one form of yarn tension equalizing device, and
FIGURE 2 is a similar view illustrating another form of such device.
, The device of FIGURE 1 comprises a cylinder 1 which is rotated at a peripheral velocity higher than the speed of travel of the yarn, two yarn guides 2 and 2 each comprising a freely running pulley mounted at the end of a curved bar 3, 3, the bar 3 being adapted to pivot about a point 4 and the bar 3' about a point 4'. The other ends of the said bars (i.e., the ends remote from the yarn guides 2 and 2) are connected by a spring 5 working in tension. Alternatively, there may be employed two independent return springs, one for each bar. The path of the yarn is indicated at 6.
The device of FIGURE 2 comprises, in addition to the same elements as that of FIGURE 1, two fixed y-arn guides 7 and 7'. The path of the yarn diliers from that of FIG- UR-E 1 and is illustrated at 6'. Y
In both devices, when an increase of the tension in the yarn occurs, the yarn guides 2 and 2' move towards one another, so that the arc embraced by the yarn on the cylinder 1 is increased. Since the cylinder 1 rotates at a peripheral velocity higher than the linear speed of the yarn, as the arc of contact is increased so is the driving force exerted by the cylinder on the yarn and the tension in the yarn is thus reduced.
When the tension in the yarn falls, the yarn guides 2 and 2' move away from one another under the action of the spring 5; the arc embraced by the yarn on the cylinder is reduced, and with it the force with which the yarn i driven by the cylinder, so that the tension in the yarn is increased.
The device of the invention is thus self-adjusting, and makes it possible to maintain a uniform tension in the travelling yarn. The value of this tension may be ad justed in various Ways, notably by varying the return force of the spring 5, an increase of which produces an increase in the tension, or by varying the surface state of the cylinder 1 or by changing the material of which it is made, whereby the coefficient of friction between the yarns and the cylinder, and consequently the tension in the yarn for a given ratio of a cylinder speed to yarn speed, is changed.
The spring working in tension may be replaced by any other equivalent system, e.g., by a spring working in flexure, in torsion or in compression,.a counter-weight, a pneumatic jack, or a magnetic or electromagnetic device of the plunger type or the repulsion type.
I claim:
1. A device for automatically equalizing the tension in a travelling yarn, comprising a cylinder adapted to be rotated at a peripheral speed greater than the rate of travel of the yarn and in the same direction, yarn guide mean positioned to cause the yarn to travel through at least one are in contact with the surface of the cylinder and including at least one movable yarn guide mounted so as to be moved by an increase in the tension of the yarn in a direction which increases the length of at least one arc over which the yarn makes contact with the cylinder, and return means tending to move the said movable guide in a direction which decreases the length of the said arc.
2. A device according to claim 1, comprising two such movable yarn guides.
3. A device according to claim 1, wherein each movable yarn guide is mounted on a bar pivoted at a point between its two ends, and the return means operates on the bar the other side of the pivot.
4. A device according to claim 3, comprising two yarn guides and a tension spring joining the two bars as the return means.
5. A device according to claim 1, wherein each yarn guide comprises a freely rotatable pulley adapted to make contact with the travelling yarn.
6. A device for automatically equalizing the tension in a travelling yarn, comprising a cylinder adapted to be rotated at a peripheral speed greater than the rate of travel of the yarn and in the same direction, yarn guide means positioned to cause the yarn to travel through at least one are in contact with the surface of the cylinder and including two movableyarn guides, each comprising a freely rotatable pulley mounted at one end of a bar pivoted at a point between its two ends, the said bars being joined beyond the said pivots by a tension spring, the arrangement being such that in operation the yarn between the movable yarn guides traverses at least one are on the cylinder, and that an increase in the tension in the yarn causes the movable yarn guides to move towards each other and so increase the distance over which the yarn make contact with the cylinder.
References Cited by the Examiner UNITED STATES PATENTS 1,752,604 4/1930 Massingham 24247.l2 X 2,854,197 9/1958 MacNcil 242-5512 3,114,512 12/1963 Peshel et a1 242-75.3 X
FOREIGN PATENTS 135,615 3/1952 Sweden.
M. HENSON WOOD, JR., Primary Examiner.
I. N. ERLICH, Assistant Examiner.
Claims (1)
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Claims (1)
Hide Dependent
translated from
1. A DEVICE FOR AUTOMATICALLY EQUALIZING THE TENSION IN A TRAVELLING YARN, COMPRISING A CYLINDER ADAPTED TO BE ROTATED AT A PERIPHERAL SPEED GREATER THAN THE RATE OF TRAVEL OF THE YARN AND IN THE SAME DIRECTION, YARN GUIDE MEANS POSITIONED TO CAUSE THE YARN TO TRAVEL THROUGH AT LEAST ONE ARC IN CONTACT WITH THE SURFACE OF THE CYLINDER AND INCLUDING AT LEAST ONE MOVABLE YARN GUIDE MOUNTED SO AS TO BE MOVED BY AN INCREASE IN THE TENSION OF THE YARN IN A DIRECTION WHICH INCREASES THE LENGTH OF AT LEAST ONE ARC OVER WHICH THE YARN MAKES CONTACT WITH THE CYLINDER, AND RETURN MEANS TENDING TO MOVE THE SAID MOVABLE GUIDE IN A DIRECTION WHICH DECREASES THE LENGTH OF THE SAID ARC.