FR2640603A1 - THREAD TENSIONING DEVICE FOR TEXTILE MACHINES - Google Patents

Abstract

Thread tensioning device for textile machines comprising rollers mounted free to rotate on a support housing and subjected to the action of a magnetic brake. According to the invention, the rollers are three in number and are mounted on the housing 1 such that, if we consider the passage of a point of the wire 4 around these rollers during its advance: - the first and the third rollers 5, 7 are positioned along fixed axes on the support housing 1; - the second roller 6 (intermediate roller) is, for its part, mounted movably on said housing 1 and can take two positions, one out of contact with the two aforementioned rollers 5, 7 in the absence of wire (non-working position), the other, in tangential contact with the first roller 5 during startup and in normal operation, thus ensuring immediate and automatic pre-braking of the wire, pre-braking which remains constant during operation.

Description

THREAD TENSIONING DEVICE FOR TEXTILE MACHINES.

  The present invention relates to a new type of wire tensioner which can be used on any type of textile material and more particularly on machines which make it possible to twist and / or assemble by twisting yarns.

of any kind.

  During the various processing operations that a wire undergoes during its elaboration, it is

  necessary to communicate to him such a steady

as constant as possible.

  To this end, a large number of devices

  have been proposed to date, the most

  simple process of having the wire set on

removals.

  Another widely used solution is to use tensioners consisting of two plated discs

  against each other and subjected to the action of a spring.

  Such solutions do not allow to control with

  accuracy the tension communicated over the wire,

  many other solutions have been considered. Thus, as mentioned in the preamble of French Patent 2,145,056, it has been proposed to use tensioning devices which comprise, on the one hand, a pulley whose periphery has a friction layer and which is in contact, at least on the parts of its circumference, with the textile thread and secondly,

  means for braking said pulley. These means of

  of the pulley are constituted by an eddy current brake in the form of an asynchronous type motor whose rotor is integral with the shaft

  pulley and whose stator windings are

  by an adjustable DC source.

  Such a type of tensioner which, in general,

  corresponds to the device that is the subject of the US-A-

  3 797 775 is unsatisfactory, in particular by the

  it requires a power supply

  It is therefore necessary to have as many power connections as there are tensioning devices.

  The above-mentioned French patent 2 145 056 aims to over-

  this disadvantage, the braking device de-

  crit being constituted by an electric generator whose retor is integral with the pulley shaft and whose armature is connected to a load resistor, the

  magnetic field of the generator being provided by a

permanent mantle.

  A comparable solution is described in French Patent 2 167 957, patent in which the braking of the guide pulley of the wire is obtained by using a magnet whose number of magnetic poles is even, this magnet being disposed opposite a disc whose face is pierced with several holes, disc which supports the wire guide pulley. Braking of the pulley is obtained by varying the distance between the disc and

the magnet.

  These solutions, which can be summarized by the expression "drum braked by magnetic brake", however, involve having a "drum" of relatively large diameter.

  important (around 80 to 100 mm) if we want to ob-

  hold a good bonding surface of the wire. In addition

  their, when starting, it has the disadvantage of causing voltage surges. Last but not least, these solutions require pre-braking in the absence of which there can be grip of the wire on

pulley.

  To solve these problems, it has been proposed, as is apparent from FR-A2 295 900, to provide tensioning devices comprising two rollers rotatably mounted in a housing and which touch each other along their circumferences with an adjustable pressure, at least 1 one of these rollers being provided with a tire made of a rubber-elastic material and the tendon being guided in such a manner as to cause both

  rollers as it passes through the device. Such a disc

  widely used today, is nevertheless

  the disadvantage that, particularly in view of the current high production speeds, it is

  heating of the rubber layer, which

  draws a variation in the braking rate

  functioning, a variation which affects the quality of

of the wire produced.

  Now we have found, and this is the subject of the

  present invention, a new type of device

  which overcomes the disadvantages of earlier solutions

  especially by the fact that it ensures a gradual tensioning during the launch of the machine,

  voltage that remains constant during normal operation.

  In general, the tensioning device con-

  The invention is of the type comprising rollers mounted free to rotate on a support housing, each roller being subjected to the action of an adjustable permanent magnet system (or magnetic brake), wire guides being provided on the housing upstream and downstream of said rollers if one considers the direction of movement

  wire so that the latter can be wrapped around the periphery.

  said rollers as it passes through the.

  tensioning device, and it is characterized in that

  said rollers are three in number and are mounted on

  their support case, so that if one con-

  sneers the passage of a point of the thread around these rollers during its advance:

  the first and the third rollers are posi-

  fixed axes on the support housing; the second roller (or intermediate roller) is,

  as for him, mounted movable on said case and then

  to take two positions, one out of contact of the two

  aforementioned rolls in the absence of wire (out-of-work position

  the other in tangential contact with the first roller during start-up and in normal operation, thus ensuring an immediate and automatic pre-braking of the wire and which remains constant in

running course.

  According to the invention, the pre-braking is obtained by contact of the movable roller with the fixed input roller. The tension of the thread created contributes to the flattening of the roller

mobile on the fixed entry roller.

  Various embodiments of the device according to

  the invention can be envisaged.

  Thus, the second mobile roller can be mounted on the housing by means of a lever (or the like), subjected to the action of return means (springs or counterweight) and allowing it to receive an angular displacement

  relative to the first roller; in such a case, the first

  first roller and the intermediate roller are arranged in the lower part of the support and substantially on either side of the axis of travel of the wire, the third roller being arranged, meanwhile, above the two

  rollers, its axis of rotation being disposed substantially

  depending on the axis of the wire.

  According to another embodiment, the intermediate roller is disposed above the first roller and acts by gravity on the latter; in such a case, these two rollers are arranged substantially along the axis of travel of the wire, the third roller being, for its part, offset laterally with respect to the two aforementioned rollers. The invention and the benefits it brings will be

  however, better understood thanks to the examples of

  given below for information but not limited to

  tif and which are illustrated by the appended diagrams in which:

  - Figure i illustrates schematically, seen in

  vation, a first embodiment of a tensioning device produced in accordance with the invention; - Figure 2 is also an elevational view of a variant of such a tensioner device; - Figure 3 is a partial view of another variant showing more particularly how is ensured the contact between the first roller and the intermediate roller;

  FIG. 4 illustrates another form of embodiment

  a tensioning device according to the invention, in which the intermediate roller is

  disposed above the first roller and acts on this

deny by mere gravity.

  Referring to the accompanying figures and more particularly to Figure 1, the tensioning device according to the invention, which can be mounted on any type of textile material, more particularly on machines for twisting and / or assembling by torsion wires of any kind, consists essentially of a plurality of rollers which are mounted free in

-2640603

  rotation on a support case designated by the general reference (1). Each roller is mounted in a known manner on said support (1) and is subjected to the action of means

  to adjust the voltage you want to

  to communicate to the wire during its passage, these means

  consisting of a permanent magnet system

  glable or magnetic brake of known type. Wire guides (2, 3) for the wire (4) are mounted on the support housing (1) upstream and downstream of the rollers, if we consider the direction of movement of the wire (4) so that

  the latter embarks around the periphery of the aforementioned

  during its passage through the device

  deur. According to the invention, the rollers are three in number and are mounted on a support housing (1) so that, if we consider the passage of a point of the wire (4) around these rollers during its advance: the first and the third rollers referenced respectively (5) and (7) are positioned according to

  fixed axes on the support case; -

  - the second roller (referenced 6), also designated

  by the expression "intermediate wheel" being

  to him, mounted on a movable assembly on said wood

  tier, so that it can take two positions (shown only in Figure 1), one of which

  (in dashed lines in FIG. 1) o said intermediate roller

  diaire (6) is kept out of contact with the two rollers

  mentioned above (5,7) in the absence of wire (position outside

  vail), the other, according to which the intermediate roller (6) is brought into tangential contact with the first

  roller (5) during start-up and kept in

  tact with this roller (5) in normal operation; grace

  to such an embodiment, it thus ensures a pre-

  immediate braking of the wire during start-up, this

  pre-braking remaining constant during operation

  is lying. According to the first embodiment illustrated in Figure 1, the intermediate roller (6) is mounted at the end of a lever (8) which is articulated about the axis (9) of the housing (1). This lever (8) is subjected to the action of return means constituted for example by a spring system (10) (see Figures 2 and 3). In this embodiment, the first roller (5) and the intermediate roller (6) are mounted at the bottom of the support (1) and this, substantially from

  other than the axis XX of the thread (4). The third

  the second roller (7) is, for its part, disposed above the two aforementioned rollers (5, 6), its axis of rotation being

  located substantially along the axis XX of the wire.

  In this embodiment illustrated by the FIGS.

  res 1,2 and 3, the wire (4) embeds around the various rollers (5,6,7) so that at the start

  wire and its advance, the proper voltage of

  the mechanism tends to press the roller or brake (6) against the periphery of the roller (5), which has the effect of creating an immediate pre-braking to regulate the scroll. Preferably, as well as this

  FIGS. 1 and 2 show an internal guide eyelet

  mediator (11) is provided on the housing between the output roller (7) and the wire guide (3) so that the wire

  (4) properly seam around the exit roller (7).

  The guide eyelet (11) has three functions, namely: to increase the engagement around the roller (7),

  - to divert the wire (4) from its trajectory to ob-

  to maintain a constant multiplication of tension by friction effect in the eyelets (11) and (3); - To ensure a torsion lock which must not go back to the roller (7) which, preferably is lined with rubber and which this lining would wear under the effect of the rotation of the thread back tension; this third function is necessary when the brake

  is applied to twisting processes of the wire.

  As is apparent from Figures 2 and 3, the roller

  intermediary (6) may be subject to the action of a

  fate (10) acting in tension, in compression, or even in torsion, or possibly in a steel blade

  (10) (Figure 3) ensuring the contact of said roller (6) con-

  be the input roller (5), or even by means of a

counterweight system.

  FIG. 4 illustrates another embodiment of a device according to the invention, in which the mobile roller (6) is arranged above the

  first roller (5) and acts by gravity on the latter.

  In this embodiment, the two rollers (5, 6) are arranged substantially along the axis XX of travel of the wire, the third roller (7) being, in turn, shifted

  laterally with respect to the two aforementioned rollers.

  In this embodiment, when starting the wire (4), the operating voltage ensures proper pressure between the rollers (5) and (6) and the pre-braking necessary for the smooth running.

  Such a tensioning device of particular design

  simply simple, is effective and helps to ensure

  regular and constant wire feeding without variation during operation. Such a device can be

  used on any type of textile material.

  Of course, the invention is not limited to the embodiments described above, but it covers all variants made in the same spirit. So, it should be noted that the pebbles used

  in the device according to the invention may

  a surface covered with a lining intended to increase the adhesion of the wire to the surface of the rollers, this lining being thin and possibly being based on elastomer or on the basis of any other material (flexible or even rigid), making it possible

this adhesion.

Claims (4)

  1 / Thread tensioning device for textile machines comprising rollers mounted free to rotate on a   support casing (1), each roller being subjected to ac-   of an adjustable permanent magnet system (or magnetic brake), wire guides (2, 3) being provided on the housing (1) upstream and downstream of said rollers if one considers the direction of movement of the wire. (4), so that the latter embarks around the periphery of the pebbles when   of its passage through the tensioning device,   characterized in that said rollers are three in number and are mounted on the support housing (1) so that, if we consider the passage of a point of the wire (4) around these rollers during its advance the first and third rollers (5, 7) are positioned along fixed axes on the support case (1); - The second roller (6) (intermediate roller) is, meanwhile, movably mounted on said housing (1) and can take two positions, one out of contact with the two aforementioned rollers (5,7) in the absence of wire (off-work position), the other, in tangential contact with the   first roller (5) during start-up and   normal operation thus ensuring immediate pre-braking   diat and automatic wire, pre-braking which remains con- both during operation.   2 / tensioner device according to claim 1, characterized in that the second movable roller (6) is mounted on the support housing (1) by means of a lever   (8) (or similar), subject to the action of means of   pel (10) (springs), the lever (8) being articulated about an axis (9) of the housing (1) so that the roller can receive an angular displacement relative to the first roller (5). 264060O   3 / tensioner device according to claim 2, characterized in that the first roller (5) and the roller   intermediate (6) are arranged in the lower part of the   port (1) and this, substantially on either side of the axis XX of travel of the wire, the third roller (7) being, meanwhile, disposed above the two aforementioned rollers (5,6), its axis of rotation being disposed substantially along the axis of the wire.   4 / Tensioning device according to claim 1, characterized in that the intermediate roller (6) is   arranged above the first roller (5) and acts by   on the latter, these two rollers (5,6) being   placed substantially along the axis XX of the wire (4), the third roller (7) being, in turn, shifted   laterally with respect to the two aforementioned rollers.