FR2736658A1 - DEVICE FOR INSERTING A BLIND THREAD INTO A WICK OF FIBERS - Google Patents

Abstract

The present invention relates to a device for inserting a continuous elastic core yarn into a strand of fibers in a spinning machine making it possible to obtain a finished yarn 1 of regular appearance and constant elongation. It comprises a delivery cylinder (6) driving together the strand of fibers (2) and the core thread (3), two support shafts (20) allowing the unwinding of a reel (8) of core thread. and a return roller (9) for the core wire arranged between the unwinding means and the delivery cylinder. It is characterized in that the return roller (9) is moved away from the delivery cylinder (6) by a distance (D) at least equal to 250 mm and in that the core wire (3) is free over any this distance (D), in such a way that it can follow the variations in movement of small amplitude of the wick (2) on the delivery cylinder (6). The support shafts (20) and deflection roller (9) define a first drawing train (24) of the core wire and the deflection roller (9) and the delivery cylinder (6) define a second train of core wire. 'stretching (25), the stretch coefficient of the first train (24) being greater than that of the second (25). Applications: Textile industry for the manufacture of yarns with elastic properties.

Description

DEVICE FOR INSERTING A SOUL WIRE IN A WICK

FIBER

  The present invention relates to a device for inserting an elastic core wire continuously in a fiber lock in a spinning machine, comprising a delivery cylinder driving together the fiber lock and the core wire, means for feeding a web-core spool resting on two parallel-axis bearing shafts, driven in the same direction of rotation and supporting said spool, and a web-thread return roller

  disposed between the unwinding means and the delivery cylinder.

  The manufacturing method relating to the insertion of an elastic core wire into a fiber lock in a spinning machine is well known and allows the production of a cotton thread or other material having elastic properties. , especially for the manufacture of textile articles in mesh such as T-shirts, underwear, etc., and textile articles in chains and wefts. This manufacturing process requires specific know-how to obtain a good quality elastic thread. By good quality is meant a wire produced which has, on the one hand, homogeneous elastic characteristics and therefore a percentage of elongation equivalent to different points along this wire and, on the other hand, a regular external appearance, without exceeding the outer core thread at the outer periphery of said finished thread. A product yarn whose elastic characteristics are homogeneous makes it possible to obtain a knitted or woven product of regular appearance. In the opposite case, the differences in elasticity generate tighter meshes than others. This can cause herringbone in the woven or knitted product. A product yarn whose external appearance is regular makes it possible to obtain a knitted or woven product of uniform color. In the opposite case, if the core wire appears at the periphery of the finished wire, it causes color differences since it does not have the same dyeing characteristics as that of the wick, being of a different nature. These color differences can result in darker or lighter spots or marks on the woven product

or knitted.

  Known devices do not achieve a level of quality sufficient to avoid the defects mentioned above. Generally, the return roller of the core wire is located near the delivery cylinder. It turns out that during its travel, the fiber wick does not keep a constant position on the delivery cylinder. On the contrary, this position oscillates on either side of a central point in a random manner. Therefore, the meeting point between the core wire and the fiber tow is not constant. If the return roller of the core wire is too close to the delivery cylinder, the core wire does not have enough freedom to follow the movement of the wick on said delivery cylinder. It follows from defects

  positioning the core wire relative to the center of the fiber tow.

  On the other hand, the known devices generally comprise only a single drawing train between the unwinding point of the core wire coil and the return roller. Stretching the core wire is insufficient for it to be stabilized at its remanent position. As a result, when it is inserted into the fiber bundle, it still stretches randomly and

  causes differences in elongation in the finished yarn.

  The present invention is an improvement of the device described in French Patent No. 2,668,174 and its main purpose is to overcome the

  disadvantages mentioned above.

  This object is achieved by a device as defined in the preamble and characterized in that the return roller is spaced from the delivery cylinder by a distance of at least 250 mm, in that the core wire is free on all this distance, so that it can follow the variations of displacement

  of low amplitude of the wick on the delivery cylinder.

  In a preferred embodiment of the invention, the device comprises drawing means of said core wire comprising a first drawing train defined by the support shaft and the return roller and a second drawing train defined

  by the return roller and the delivery cylinder.

  The coefficient of stretching of the first drawing gear is advantageously

  greater than the coefficient of stretching of the second drawing train.

  The coefficient of stretching of the first drawing train can be between 80 and 98% and preferably close to 95% and the drawing coefficient of the second drawing train can be between 2 and 20% and preferably close to of 5

%.

  According to the preferred embodiment, the support shafts, the return roller and the delivery cylinder are driven independently by motors

  individual powered by electronic variable speed drives.

  The device may comprise a programmable central control unit

  which controls said individual motors.

  The distance between the return roller and the delivery cylinder is preferably

adjustable.

  According to the preferred embodiment, the return roller comprises a central V-shaped groove, the bottom of said groove having a section

  in an arc whose radius depends on the diameter of the core wire.

  The present invention and its advantages will become more apparent in the

  following description of an exemplary embodiment, with reference to the drawings

  appended in which: - Figure 1 is a schematic elevational view of a part of a spinning machine provided with two devices according to the invention, and - Figure 2 is a detailed view of the return roller of the device of the invention. With reference to FIG. 1, the exemplary embodiment illustrated relates to a known type of machine, continuously manufacturing at least two similar wires 1 each of which is formed from a wick of cotton fibers 2, or of another material, and an elastic core wire 3, generally made of synthetic material of the LYCRA type. The two son I are then winded or wound together in a not shown portion of the machine. Each of the fiber tows 2 is delivered, in the direction indicated by the arrows A, by a device not shown, passes through a drawing bench 5, then passes on a delivery cylinder 6 against which it is applied by a pressure roller 7. Each core wire 3 is unwound from a coil 8 and passes over a return roller 9 before being introduced between the pressure roller 7 and the

  delivery cylinder 6 to join the wick 2 in the forming wire 1.

  The return roller 9 is positioned at an adjustable distance D from the delivery cylinder 6 so that the core wire 3 is free to follow the movement of the fiber lock 2 on the delivery roll 6. In this way, the core wire 3 is automatically positioned inside the wick whatever the position of the insertion point on the delivery cylinder 6. The distance D is adjustable, the return roller being mounted on a mobile support by means of a screw / nut system or by a jack (not shown). It can be variable from 250 to 400 mm but must not be less than 250 mm

  for the reasons mentioned above.

  In the device according to the invention, each coil 8 of core wire 3 rests freely on two similar rotating horizontal bearing shafts 20 rotating in the same direction, as indicated by the arrows. However,

  two coils 8 rotate in opposite directions in the example shown.

  The two support shafts 20 of the same device are driven in synchronism at a speed V20 by means of an electric motor 21 powered by an electronic speed controller. Similarly, the delivery cylinder 6 and the return roller 9 are driven individually and respectively at a speed V6 and V9 by an electric motor 22, 23 powered by an electronic variable speed drive or by any other control device such as pulleys and timing belts. This type of drive makes it possible to precisely adjust the respective speeds V20 and V9 as a function of the speed V6 which is generally defined according to the technical characteristics of the fiber tow. The adjustment, once performed, remains stable and ensures a circumferential speed quite constant coil 8 relative to that of the return roller 9 and the delivery cylinder 6, so a regular tension of the wire 3 between these three elements. This insertion device is provided with means for drawing the elastic core wire 3 between the bearing shafts 20 and the delivery cylinder 6. These drawing means comprise two drawing trains, a first 24 defined by the support shafts 20 and the return roller 9 and a second 25 defined by the return roller 9 and the delivery cylinder 6. The draw coefficient of the first drawing bench 24 which is obtained by the difference of the speeds V9 - V20 is greater than the draw coefficient of the

  second drawing bench 25 which is obtained by the difference of the speeds V6 -

  V9. For example, if the total draw coefficient of the core wire is to be 3.38, the first draw bench 24 will be set to obtain a coefficient of 3.25 and the second draw bench 25 to a coefficient of Generally, the draw coefficient of the first drawing train is between about 98% and is preferably about 95% and the drawing coefficient of the second drawing train is between 2 and 20% and is preferably close to 5%. It is obvious that a wide range of draw coefficient can be obtained without limitation. This double stretching train makes it possible to stabilize the elasticity of the core wire 3 at its residual position after a pre-stretching obtained thanks to the first drawing bench 24. The adjustment values of these speeds V20 and V9 are dependent on the nature and quality of the core wire 3 and the desired elastic properties in the wire produced 1. According to these criteria, the operator sets the speeds V20, V9 and V6 at startup by testing. These adjustments are easily achievable via the electronic variable speed drives associated with each motor 21-23. A programmable central control unit 26 can advantageously supplement this device in such a way as to centralize the adjustment criteria and the control parameters of the variable speed drives, and to memorize adjustment programs defined with respect to a

  type of core wire 3 and a type of fiber tow 2.

  Figure 2 illustrates in detail the return roller 9 of said device. This roller is preferably made of heat treated steel to have a surface state with a very low coefficient of friction and a high mechanical strength. It comprises a V-shaped groove 27 making it possible to perfectly guide the core wire 3. The bottom 28 of the groove comprises an arcuate profile whose radius depends on the diameter of said core wire 3. This rounded profile allows to guide the soul wire in good conditions without risking

  to damage it, to cut it or to scrape it by a sharp angle.

  The present invention is not limited to the embodiment described but extends to any modification and variation obvious to a person skilled in the art.

Claims (8)

claims   Device for inserting an elastic core wire (3) continuously in a fiber bit (2) in a spinning machine, comprising a delivery cylinder (6) together driving the fiber tow (2) and the core wire (3), means for unwinding a web core coil (8) (3) resting on two parallel axis bearing shafts (20) driven in the same direction of rotation. rotation and supporting said coil (8), and a return roller (9) of the core wire (3) disposed between the unwinding means (8, 20) and the delivery cylinder (6), characterized in that the roller a distance (D) at least equal to 250 mm from the delivery cylinder (6) and that the core wire (3) is free over the entire distance (D) of such distance way that it can follow the variations of small amplitude displacement of the wick (2) on the delivery cylinder (6).   2. Device according to claim 1, characterized in that it comprises drawing means of said core wire (3) comprising a first drawing train (24) defined by the support shaft (20) and the return roller (9) and a second   stretching machine (25) defined by the return roller (9) and the delivery cylinder (6).   3. Device according to claim 2, characterized in that the draw coefficient of the first drawing train (24) is greater than the drawing coefficient. the second stretching train (25).   4. Device according to claim 3, characterized in that the coefficient of stretching of the first drawing train (24) is between 80 and 98% and preferably close to 95% and the draw coefficient of the second train of 'drawing   (25) is between 2 and 20% and preferably close to 5%.   5. Device according to claim 1, characterized in that the bearing shafts (20), the return roller (9) and the delivery cylinder (6) are independently driven by individual motors (21-23) supplied with   electronic speed controllers.   6. Device according to claim 5, characterized in that it comprises a programmable central control unit (26) which controls said individual motors (21-23).   7. Device according to claim 1, characterized in that the distance (D)   between the return roller (9) and the delivery cylinder (6) is adjustable.   8. Device according to claim 1, characterized in that the return roller (9) comprises a groove (27) central V-shaped, the bottom (28) of said throat having a section in an arc whose radius depends the diameter of the core wire (3).