Method of processing a fleece in a pre-needling apparatus, and an installation implementing such a method

Abstract

A needle loom (2) for the consolidation of a fleece is preceded in the same installation by a pre-needle loom (3) having an “elliptical” movement, i.e. the needles (47) of which have a component of movement in the direction (6) of the progression of the fleece of fibres when they are in penetration phase in the fleece. The component is used as an additional way of propulsion of the fleece into the entrance to the needle loom (2).

Description

This invention relates to a method of processing a fleece in a pre-needling apparatus and then in a consolidation apparatus.

This invention also relates to an installation for the implementation of the method.

A non-consolidated fibre fleece is in general made up of superimposed layers of fibres supplied for example by a crosslapper. In each layer, the fibres are parallel to each other. However, the direction of the fibres in one layer is different from the direction of the fibres in the layer immediately beneath and in the layer immediately above.

A non-consolidated fleece must be processed in a consolidation machine which has the task of interlinking the fibres, in particular from one layer to another, concomitantly compacting the fleece. Once consolidated, the fleece has considerable mechanical strength. It is therefore relatively easy to extract the fleece from the consolidation machine, for example by passing the fleece between two pinch rolls.

Upstream of the consolidation machine, the mechanical strength of the fleece is, by contrast, virtually non-existent, whether in longitudinal compression or in longitudinal traction. As a result, the introduction of the fleece into the consolidation apparatus is a difficult problem with nonwoven fabrics lines. If subjected to excessive stress during introduction into the consolidation machine, the fleece becomes irregulary deformed and is then consolidated with irreversible irregularities in its surface weight. The product obtained is then of poor quality.

A well-known apparatus for the consolidation operation is the needle loom. In such a machine, multiple needles oriented transversely to the plane of the fleece are rapidly reciprocated in order to periodically pass through the fleece and thus interweave the fibres of the different layers. If pinch rolls are placed at the exit from a needle loom, the traction on the consolidated fleece is transmitted to the entrance of the needle loom only when the needles are in their withdrawal phase, i.e. disengaged from the fleece. And in any case, given the low strength of the fleece upstream of the needle loom, this traction transmitted via the needle loom is capable of damaging the homogeneity of the fleece.

In order to deal with this problem, needle looms with a so-called “elliptical” movement have been proposed. This term means that in profile view a point of the needles describes an oval or ovoid path resembling an ellipse, without necessarily being exactly an ellipse. In the mathematical sense of the term. In such needle looms, the needles are given a combined movement comprising said reciprocating penetration movement as a first component, and a superimposed second component parallel to the direction of progression of the fleece through the needle loom. This second movement takes place in the same direction as the progression of the fleece when the needles are in penetration phase, and in the return direction when the needles are in withdrawal or disengagement phase.

Documents DE-A-1 803 342, FR-A-2 180 928, U.S. Pat. No. 5,732,453, and EP-A-892 102 describe such needle looms with an “elliptical” movement.

As the needles follow the progressive movement of the fleece while they are in penetration phase, there is no longer the problem of a stretching of the fleece between the pinch rolls and the needles when the needles are in penetration phase. At the same time, the needles in penetration phase, by their movement in the direction of the progression of the fleece, help the latter to penetrate inside the needle loom.

However, these needle looms have the drawback of being expensive and mechanically complex, and of comprising a large number of moving parts, some of which are heavy and bulky. This results in vibrations on the one hand, and air movements on the other hand. The latter are very disadvantageous for the non-consolidated fleece in the form in which it enters the needle loom. The air movements tend to disperse the non-interlinked fibres and as a result to create inhomogeneities and irregularities in the width of the fleece.

Cylinder-type pre-needle looms are also known in which pre-needling needles are linearly reciprocated transversely to the plane of the fleece leaving for example a crosslapper. Before penetrating the fleece, the needles pass through the orifices of a cylinder which is driven for rotation in the direction of progression of the fleece and the outer peripheral wall of which is in contact with the fleece. This cylinder therefore acts as a movable stripper roller, the outer surface of which, in contact with the fleece, accompanies the movement of the fleece. The strike rate of the needles and the circumferential displacement of the cylinder correspond to one or more successive circumferential pitches of the orifices. Thus the needles coincide each time with respective orifices of the cylinder.

At the exit from such a pre-needle loom, the fleece is pre-consolidated, therefore capable of transmitting a certain tractive force, and its passage through the subsequent needle loom is therefore facilitated. Moreover, the pre-consolidated fleece already has a certain cohesion allowing it for example to be stored and finally consolidated only later, and/or far away. However, cylinder-type pre-needle looms have certain limitations and drawbacks. As the needle support is inside the cylinder it can be supported only at its ends situated on either side of the width of the fleece. The problem of the bending of the needle support makes it necessary to limit the operating rate and the number of needles, especially with broad fleeces. On the other hand, the orifices of the cylinder are substantially fixed relative to the fleece, such that the pre-needling work, instead of being uniformly distributed over the surface of the fleece, is concentrated on the points of the fleece which have coincided with the orifices of the cylinder. This results in a marking which cannot always be removed by the subsequent consolidation process.

The object of this invention is thus to propose a method and an installation which make it possible to consolidate a fibre fleece at a relatively high rate with a particularly small deformation of the fleece.

According to the invention, the method of processing a fleece in a pre-needling apparatus and then in a consolidation apparatus, a method in which the pre-needling needles are caused to carry out a combined movement comprising a reciprocating movement transversely to the plane of the fleece and a progressive movement in the direction of progression of the fleece when the needles are in penetration phase in the fleece, is characterized in that the progressive movement of the pre-needling needles is used to impart to the fleece a movement promoting introduction into the consolidation apparatus.

According to the invention, the “elliptical”-type combined movement relates only to a pre-needling which can be carried out with a relatively small number of needles, as well as a relatively small volume and mass of moving parts, and even, according to a possible feature of the invention, at a reduced rate compared with that of the consolidation apparatus. Thus the air movements, vibrations and additional mechanical stresses inflicted on the installation by the horizontal component of the movement are limited, while still applying this horizontal component where it is really necessary, i.e. on entering the actual consolidation process.

Preferably, according to the invention, the fleece is passed directly from the pre-needling apparatus to the consolidation apparatus, preferably carrying out the pre-needling and the consolidation in the same machine. This minimizes the space requirement while further optimizing the effect of propulsion of the fleece towards the consolidation apparatus, an effect which results from the progressive movement of the pre-needling needles. If the consolidation consists of a needling with a linear movement of the needles, an advantageous version of the method according to the invention consists of actuating the pre-needling needles and the needling needles at the same rate and synchronizing the pre-needling and needling cycles such that the needling needles are in penetration phase during the withdrawal phases of the pre-needling needles, and the needling needles are in withdrawal phase when the pre-needling needles are in penetration phase.

Thus, when the pre-needling needles are in penetration phase and carry out their progressive movement with the fleece, the needling needles in withdrawal phase allow progression of the fleece which can concomitantly be pulled by pinch rolls at the exit from the needle loom. On the other hand, when the pre-needling needles are in withdrawal phase and as a result are no longer propelling the fleece, the needling needles penetrate under optimum conditions through a fleece which is stationary or moving at a reduced speed, while the pinch rolls at the exit from the needle loom being may be stopped or respectively slowed down.

The actuation of the needling needles and the pre-needling needles at the same rate or at two different rates but in a fixed ratio simplifies the drive means of the pre-needling apparatus and the consolidation apparatus. For example a single-motor system and fixed-ratio transmission means linking this motor system and the two apparatuses can be provided.

In a more sophisticated version, a separate motor system can be provided for pre-needling and needling by means of respective servomotors subject to a common control which prescribes their set position at any given moment. This defines the speed ratio between the two apparatuses and, when this ratio is an integer or a fraction the numerator and the denominator of which are integers, their cycle setting.

According to a second aspect of this invention, the installation for processing a fibre fleece, for the implementation of a method according to the first aspect, comprising, along a path for the fibre fleece, a pre-needling apparatus followed by a consolidation apparatus, the pre-needling apparatus comprising means for imparting to pre-needling needles a combined movement comprising a reciprocating movement transversely to the plane of the fleece and a reciprocating movement substantially parallel to the progressive movement of the fleece, is characterized in that the exit from the pre-needling apparatus and the entrance to the consolidation apparatus are in a relationship that preserves the progressive movement of the fleece.

It is advantageous to carry out the needling starting with needles penetrating the fleece on its face opposite that from which the pre-needling has just been carried out.

As a result, the pre-needling apparatus can be arranged closer to the needling apparatus. This improves the effect of propulsion of the fleece by the pre-needling apparatus into the needling apparatus. At the same time the overall space requirement is reduced and the textile result is improved.

Preferably, separately or in combination:

the exit from the pre-needling apparatus and the entrance into the consolidation apparatus are directly linked;

the pre-needling apparatus and the consolidation apparatus are installed in the same machine;

the pre-needling apparatus comprises, between the path of the fleece and a support for the needles, a stripper table provided with orifices through which the needles extends, these orifices having, parallel to the direction of progression of the fleece, a dimension sufficient to allow the longitudinal reciprocating movement of the needles; the stripper table preferably being extended all in one piece, by a needling table of the consolidation apparatus.

According to an aspect of this invention relating to the present pre-needling and more generally to elliptical needling, there is preferably provided on the side opposite the pre-needling needles a support means that can move with the fleece and which delimits the path of the fleece. The support means is preferably a rotating roller having recesses for the needle tips; these recesses preferably being gaps between annular strips.

According to another aspect of the elliptical pre-needling according to the invention, and of elliptical needling in general, the apparatus comprises, for delimiting the path of the fleece on the side opposite the needles having an elliptical movement:

support strips in planes parallel to the direction of progression of the fleece; and

between the strips, recesses for receiving the needle points.

In one or other of the two aspects which have just been described, the bottoms of the recesses are preferably formed by fingers which extend beyond the strips in the direction towards the following apparatus, therefore in particular the consolidation apparatus.

Another important aspect of this invention relates to a mechanism capable of giving the needles an advantageous elliptical movement.

This mechanism comprises, in particular in the pre-needling apparatus according to the invention, a movable structure with a support for the needles and attached to two crank-connecting-rod systems by two parallel positioning axes, and eccentricity radii of the two crank connecting-rod systems are capable of a mutual orientation such that dead centres of the respective strokes of the two positioning axes are time-lagged relative to each other.

The phase shift is preferably adjustable, which has the effect of adjusting the amplitude of the movement component of the needles parallel to the direction of progression of the fleece.

Preferably in this mechanism, separately or in combination:

the movable structure is slidingly guided in a slide oscillating about an axis parallel to the positioning axes and each crank connecting-rod system comprises a connecting rod one small end of which is articulated to the structure about one of the positioning axes;

the slide is placed substantially between two eccentric means turning in mutually opposite directions and each belonging to a respective one of the two crank connecting-rod systems.

Preferably, the two connecting rods are oriented with their ends forming a connecting-rod small end pointing in a direction generally away from the plane of the fleece.

Thus, the process of reversing the direction of the vertical component of the movement of the needles in the vicinity of the position of maximum penetration takes place very slowly, with a virtual stoppage time during which part of the movement of the needles in the direction of the progression of the fleece takes place efficiently and under good conditions. Moreover, so arranged, the mechanism is particularly compact.

Other features and advantages of the invention will also emerge from the following description, which relates to non-limitative examples.

In the attached drawings:

FIG. 1 is a diagrammatic elevational, partly sectional view, of a first embodiment of the installation according to the invention;

FIGS. 2 and 3 are part-sectional views along II-II and III-III of FIG. 1 respectively;

FIG. 4 is a view similar to FIG. 1 but simplified and showing another operating stage;

FIG. 5 is an enlarged-scale view of part of the installation of FIGS. 1 to 4 in a part-sectional side elevation, and at a third operating stage; and

FIGS. 6, 7 and 8 are views generally similar to FIG. 1 but relating to three other embodiments of the installation according to the invention.

In the example represented in FIG. 1, the installation comprises, along a path 1 for a fibre fleece (not shown in FIG. 1), a consolidation apparatus 2 directly preceded according to the invention by a pre-needling apparatus 3. There are moreover provided a feed apparatus 4 upstream of the pre-needling apparatus 3 relative to the direction of progression 6 of the fleece, and an extractor apparatus 7 situated downstream of the needling apparatus 2 and constituted by two rotating rollers 8 defining between them a pinch line or nip 9 for the fleece along the path 1 which is substantially plane.

In the following, “distal” and “proximal” respectively mean “relatively remote from” and “relatively close to” the plane of path 1.

The pre-needling apparatus 3 and the needling apparatus 2 are jointly housed in a single box 11 and thus form part of a same machine. The box 11 has an entrance window 12 in which the feed apparatus 4 is installed and an exit window 13 in which the extractor apparatus 7 is installed.

The needling apparatus 2 is itself of standard design. Structure 14 is linearly reciprocable along a fixed sliding direction 16, which is perpendicular to the plane of the path 1 of the fleece. A sliding rod 17 forming part of the structure 14 is slidingly mounted in a sliding guide 18 which is secured to a frame 19 of the machine, to which the box 11 is also secured. The structure 14 also comprises a support 21 which is secured to the proximal end of the rod 17 and a needle bar 22 interchangeably secured onto the support 21. Needling needles 23, only two of which are shown and the others diagrammatically represented by the dot-dash line 23a, are oriented perpendicularly to the plane of the path 1 and distributed over the surface of the bar 22. In the region of the needles 23, the path of the fleece is defined by a needling table 24 adjacent to the face of the fleece opposite the needle bar 22, and by a stripper plate 26 adjacent to the face of the fleece turned towards the needle bar 22. The table 24 and the stripper plate 26 have orifices through which the needles 23 pass when they are in the position of maximum penetration shown in FIG. 1.

For the generation of the reciprocating movement, the needling apparatus 2 includes a connecting rod 27 the big end 28 of which is articulated to an eccentriated journal 29 of an eccentric shaft 31, and the small end 32 of which is articulated to the distal end of the sliding rod 17. The shaft 31, supported in rotation in a bearing 33 integral with the frame 19, is driven in rotation by an adjustable-speed motor, not shown.

The pre-needling apparatus 3 comprises a movable structure 36 (see FIG. 5) in turn comprising at least one rod 38, and in practice several rods 38 which are aligned in the direction of the width of the fleece, and only one of which is therefore visible in FIG. 5.

In the following, in order to simplify the description, it is in general considered that there is only one rod 38, as well as a single set of guiding and actuating means for this rod.

At its proximal end, the rod 38 is rigidly secured to a support 44. A needle bar 46 is interchangeably secured to the support 44, on the face of the support 44 facing away from the rod 38. The bar 46 carries pre-needling needles 47 which extend towards the fleece 41 parallel to the longitudinal axis 42 of the rod 38.

The sliding rod 38 is fitted to slide along its longitudinal axis 42 in a guide 39 which it itself pivotably supported in the frame 19 about an axis of oscillation 37 which is parallel to the width of the fibre fleece. The axis 37 intersects the longitudinal axis 42 of the sliding rod 38. The intersection of the axes 37 and 42 is in the middle of the axial length of the bore of the guide 39 in which the rod 38 slides. By actuating means which will be described hereafter, the longitudinal axis 42 oscillates about the axis of oscillation 37 on either side of a general axis 43 passing through the intersection of the axes 37 and 42, and perpendicular to the plane of the path 1, in order to impart to the movable structure 36 both a reciprocating movement in a direction of penetration transverse to the plane of the path 1 of the fleece 41, and an oscillating movement about the axis of oscillation 37 integral with the frame 19. The oscillation movement is intended to impart to the needles 47 what is called a “progressive” component of movement, essentially parallel to the direction of progression 6 of the fleece. Thus, there is between the needles 47 and the frame 19 of the machine a kinematic linkage comprising a sliding which is mechanically in series with an articulation. In this example, starting from the needles 47 there is first the sliding of the rod 38 in the guide 39, then the rotation of the guide 39 in the frame 19.

The kinematic linkage in question means that there is between the needles and the frame of the machine a mechanical part, in this case the guide 39, which is guided in rotation relative to one of the two elements, here the frame, and slidingly guided relative to the other element, here the needles. This kinematic linkage does not otherwise have an actuating function.

Moreover, in this embodiment, the sliding guide surface of the guide 39 is situated inside its cylindrical surface 40 of articulation on the frame. Thus, the two guide means are extremely close to each other, and the accumulated plays are as small as possible, the guiding of the movable structure 36 relative to the frame being almost as precise and robust as a simple and single articulation.

The pre-needling installation 3 also comprises an actuating mechanism which in turn comprises two eccentric shafts 48a, 48b rotatably supported by the frame 19 about axes 49a, 49b parallel to the axis of oscillation 37 and situated symmetrically on either side of the general axis 43. The actuating mechanism also comprises two connecting rods 51a, 51b the big end 52a, 52b of which is articulated to a respective eccentric journal 53a, 53b of the eccentric shafts 48a, 48b. The small end 54a, 54b of each connecting rod 51a, 51b is articulated to the oscillating-sliding rod 38 about a respective positioning axis 56a, 56b. The positioning axes 56a, 56b are close to the distal end of the rod 38. Along the axis 42 and the rod 38, the guide 39 is situated between the support 44 on the one hand and the positioning axes 56a, 56b on the other hand.

The arrangement is such that the two connecting-rod small ends 54a, 54b obliquely point towards each other, and away from the path 1 of the fleece. The two positioning axes 56a, 56b are arranged symmetrically relative to the axis 42 of the oscillating-sliding rod 38. Moreover the positioning axes 56a and 56b are relatively very close to each other. This reduces the stresses to which the rod 38 is subjected, and therefore makes it possible to lighten the latter. The eccentricity radii 61a, 61b of the connecting-rod big end axes are the same length, and the length of the connecting rods 51a, 51b between the connecting-rod big end axis and the connecting-rod small end axis is the same.

The two eccentric shafts 48a, 48b are driven in opposite rotational directions and at equal rotation speed, as indicated by arrows 57a, 57b, for example by means of intermeshed toothed wheels 58a, 58b (FIG. 1), each turning integrally with a respective one of the shafts 48a, 48b. In the example shown, the arrangement and the rotation directions 57a, 57b are such that when the eccentrated journals 53a, 53b carry out the part of their travel directed towards the plane of the path 1 of the fleece, the connecting rods 51a, 51b work in traction and are substantially perpendicular to the plane of the fleece. They thus very efficiently transmit their force for the penetration of the pre-needling needles 47 into the fleece 41. During the lift phase, illustrated in FIG. 5, the connecting rods 51a, 51b are much more oblique, they work in compression and in a less favourable orientation, but the effort to be provided is less. Overall, the distribution of efforts over a cycle is optimized, which makes it possible to lighten the mechanism, and therefore the inertia forces and vibrations. This further increases the possible lightening.

The mechanism comprises means for shifting the phase of the shaft 48b relative to the shaft 48a. These means are diagrammatically represented in FIG. 5 by an adjustment 59 of the angular position of the shaft 48b relative to the toothed wheel 58b driving said shaft 48b in rotation about its axis 49b. In practice, in a preferred embodiment, the illustrated adjustment means 59 is replaced by:

a clutch between the toothed wheel 58b and the corresponding eccentric shaft 48b;

an angle encoder on the eccentric shaft 48a and also, preferably, another angle encoder on the shaft 48b; and

a brake on the eccentric shaft 48b.

During needling operation, the clutch is engaged and the brake is released.

In order to carry out a phase-shift adjustment, the brake is applied, the clutch is disengaged and the shaft 48a is rotated for example by means of the drive motor until the desired phase-shift is obtained, monitored by means of the angle encoder(s). Then, the clutch is re-engaged and the brake released.

Preferably the clutch discs have, on their contact surface, teeth which fit into each other while the clutch is engaged. The angular pitch of these teeth is typically of angle-degree order.

The adjustment of the phase-shift angle between the radii 61a and 61b allows adjustment of the length of the longitudinal component (parallel to the direction of progression of the fleece 41) of the movement of the needles 47.

If the phase shift 59 is adjusted such that the two eccentricity radii 61a, 61b are arranged symmetrically relative to the general pre-needling axis 43, then the pre-needling takes place strictly along the axis 43, i.e. the axes 42 and 43 coincide for all the angular positions of the eccentric shafts 48a, 48b. This is because, in any angular position of the shafts 48a and 48b, the polygon defined by the axes 37, 49a, 53a, 56a, 56b, 53b and 49b exhibits mirror symmetry relative to the axis 43. The movement obtained for the needles 47 is a movement analogous to that of a simple crank connecting-rod system such as that described for the consolidation apparatus 2, but with two exceptions:

• • thanks to the reversal of the connecting rods 51a, 51b, i.e. with the connecting-rod small ends 56a, 56b in distal position, that of the two dead centres (reversal point of the direction of movement of the rod 38) for which the absolute acceleration value is lowest is that corresponding to the maximum-penetration position of the needles 47 in the fleece 41, the position represented in FIG. 4;
  • thanks to the use of two connecting rods and two eccentrics, this effect of smoothness of the change of direction at the maximum-penetration point is further increased.

In practice, as more precisely illustrated in FIG. 5, the adjustment device 59 is set so that the eccentric shaft 48b situated to the rear relative to the direction of progression 6 of the fleece lags relative to the shaft 48a situated ahead.

This has three consequences:

• • When the rod 38 moves away from the fleece 41, the connecting rod 51a situated ahead is at the same time more distal than the other connecting rod 51b, whereby the distal end of the rod 38 is displaced towards the rear; as a result the proximal end of the rod 38 is offset towards the front, and the set of needles 47 is itself offset in the direction 6 relative to the axis 43, as represented in FIG. 5;
  • During the drop phase, this is reversed, the connecting rod 51a ahead of the other is more proximal and maintains the proximal end of the rod 38 in a position tilted towards the rear;
  • A significant part of the movement of the needles 47 towards the front occurs in the vicinity of the maximum-penetration position in the fleece, where the reversal of the direction of the vertical component of movement takes place with accelerations that are further reduced due to the non-coincidence of the dead centres of the two crank connecting-rod systems, and a significant part of the tilting from the front towards the rear takes place in the vicinity of the maximum-withdrawal position of the needles 47.

The guiding and actuating means described allow the needles 47 to be given, as “elliptical” trajectory, an ovoid trajectory tapering towards the fleece. In other words, the movement of the needles has a progressive component which accompanies the progressive movement of the fleece over a proximal part of the penetration stroke which is greater than half of the total penetration stroke. This proximal part of the penetration stroke constitutes the useful stroke along which the needles can engage the fleece while accompanying its progressive movement.

The pre-needling apparatus 3 also comprises a support means 62 for the fleece 41 on the side of the fleece facing away from the needles 47, and a stripper plate 63 which defines the path of the fleece 41 on the side of the fleece facing the needles 47.

The stripper plate 63 (see also FIG. 2) comprises a core 64 which is generally plane and parallel to the plane of the path 1 (plane of the fleece 41), and longitudinal ribs 66 extending from the core 64 towards the path 1 so that the free longitudinal edges of the ribs 66 define the position of the face of the fleece 41 facing towards the needles 47. The core 64 has, between the ribs 66, longitudinal slots 67 through which the needles 47 pass in order to pierce the fleece 41. In the example represented in FIG. 2, there are three slots 67 between two adjacent ribs 66.

In the example, the needles 47 are represented arranged in rows parallel to the longitudinal direction of the fleece (FIG. 5). Each row occupies a slot 67. The length of each slot 67 is sufficient for the needles 47 to be able to carry out the longitudinal component (parallel to the direction of progression 6 of the fleece 1) of their movement.

The support means 62 comprises a rotating roller 68 having an axis 69 parallel to the width of the fleece 41. The cylinder 69 comprises a core 71 and annular ribs 72 which project outwards from the core 71. The annular ribs 72 extend in planes parallel to the direction of progression of the fleece 41 and support the fleece 41 in its portion located in front of the needles 47, on the side of the fleece 41 facing away from the needles 47. Preferably, as represented in FIG. 2, the ribs 72 are facing the ribs 66 of the stripper plate 63. The cylinder 68 is driven in rotation in a manner which will be described in detail hereafter so that the free peripheral edges of the ribs 72 contribute to the movement of the fleece 41 by means of a frictional contact with the latter.

The ribs 72 form recesses 73 (FIG. 2) therebetween, which receive the tips of the needles 47 when they are in maximum-penetration position through the fleece 41. The bottoms of the recesses 73 are formed by fingers 74 which, as shown in FIGS. 1, 4 and 5, extend beyond the ribs 72 towards the consolidation apparatus, until they are virtually in contact with the needling table 24, in order to define the corresponding side of the path of the fleece between the action zone of the pre-needling needles 47 and the needling consolidation apparatus 2. The core 71 of the cylinder 68 turns inside a circular bore 76 of each of the fingers 74. Upstream of the action zone of the pre-needling needles 47 (FIG. 5), each finger 74 forms a boss 77 supporting the fleece 41 substantially in the same plane as the most proximal point of the ribs 72. Downstream of this boss 77, the fingers 74 are hollowed out at 78 in order to create the recesses 73 (FIG. 2) allowing the needles 47 to travel.

On the side of the fleece 41 which faces the needles 47, the stripper plate 63 extends on one side downstream as far as where the stripper plate 26 of the needling apparatus 2 begins, and on the other side upstream by an introductory guiding part 79 (FIG. 5) profiled in the form of an introduction ramp.

An arrow 80 illustrates that the stripper plate 63 is vertically adjustable relative to the frame 19. Similarly, the arrows 81 illustrate a possibility of vertically adjusting the support means comprising the cylinder 68 and the fingers 74. It is thus possible to adjust on the one hand the distance between the stripper plate 63 and the support means 62, and on the other hand the depth of penetration of the needles 47 through the fleece 41.

The feed apparatus 4 comprises, just upstream of the pre-needling apparatus 3, two cylinders 82 situated on either side of the plane of the path 1, defining between them a pinch slot—or nip—for gripping the fleece 41 and controlled to turn in opposite directions to each other so as to drive the fleece in the direction of progression 6, by motor means not shown in FIG. 1. As shown in FIG. 3, each cylinder 82 comprises a core 83 and a peripheral coating 84, for example of rubber, which defines peripheral grooves 86 in which are accommodated non-rotating fingers 87 which extend towards the support means 62 and the stripper plate 63 respectively. The two sets of fingers 87 delimit between them the path of the fleece between the cylinders 82 and the pre-needling apparatus 3. The nip formed between the cylinders 82 receives the fleece from an upstream convergent-belts conveyor system 88, which is sometimes called a “pre-compressor”.

In the example represented in FIGS. 1 and 5, the consolidation apparatus 2 and the pre-needling apparatus 3 have the same strike rate. This rate identity is imposed by a timing belt or a chain 89 linking the eccentric shaft 31 of the consolidation apparatus 2 to one 48a of the eccentric shafts of the pre-needling apparatus 3. In FIG. 4, two solutions are shown for the belt, in which the lower half-view of the belt, numbered 89, corresponds to the solution of FIG. 1, i.e. identity of rates. Moreover, the orientation of the eccentric shaft 31 of the consolidation apparatus 2 relative to that of the eccentric shafts 48a and 48b is such that when the needles 23 of the consolidation apparatus 2 are in maximum-penetration position (FIG. 1), the pre-needling needles 47 are in maximum-withdrawal position, and conversely, as shown in FIG. 4, when the needles 23 of the consolidation apparatus 2 are in maximum-withdrawal phase, the pre-needling needles 47 are in maximum-penetration position. In this position, as has been seen, and as indicated by an arrow 91a in FIG. 4, the needles 47 also have a component of movement in the direction of progression 6 of the fleece and the withdrawal of the consolidation needles 23 allows the fleece 41 to follow this movement. At the same time, the cylinders 8 of the extractor apparatus 7 and the cylinders 82 of the feed apparatus 4 are controlled to rotate in the direction where they drive the fleece in the direction of progression 6. Conversely, in the situation represented in FIG. 1, the penetration of the needles 23 tends to block the progressive movement of the fleece. In order to avoid unnecessary stress on the fleece, the cylinders 8 and 82 can be stopped or slowed down. At the same time, the pre-needling needles 47 in withdrawal position carry out their component of movement towards the rear of the fleece as indicated by the arrow 91b.

It can be arranged for the displacement measured at the periphery of the cylinders 82 and 8 at each pre-needling cycle to be equal to the amplitude of the component of movement of the pre-needling needles 47 parallel to the path 1 of the fleece. But different adjustments are also possible, depending on prior tests for each individual production task.

As a result, in the situation represented in FIG. 4, the pre-needling needles 47 in maximum-penetration phase engage the core of the fleece of fibres and effectively propel the fleece directly into the consolidation apparatus 2 while moreover giving the fleece a preliminary cohesion allowing the traction exerted by the extractor rollers 8 to be effectively transmitted to the whole of that part of the fleece situated between the pre-needling needles 47 and said rollers 8.

In the situation illustrated in FIG. 5, the structure 36 carries out its withdrawal movement, the axis 42 is inclined about the axis of oscillation 37, relative to the general axis 43, so that the needles 47 are offset downstream.

In the modified embodiment illustrated by the belt 89a in FIG. 4, the strike rate of the pre-needling apparatus 3 is equal to half that of the needling apparatus 2.

In this case, it is no longer possible to strictly satisfy the condition according to which the needles 23 and 47 alternately engage the fleece 41. But a particular cycle setting of the two movements relative to each other can nevertheless be sought. For example, it can be arranged for there to be a progressive movement 91a of the pre-needling needles 47 engaged in the fleece when the consolidation needles 23 are in maximum-withdrawal phase. The pinch rolls 7 can also be controlled to drive the consolidated fleece when the consolidation needles 23 are withdrawn from the fleece, and the feed cylinders 82 can be controlled to rotate when the pre-needling needles 47 engage the fleece.

The example of FIG. 6 will be described only where it differs from that of FIGS. 1 to 5.

In the movable structure 136 of the pre-needling mechanism the oscillating-sliding rod 38 of FIG. 5 is replaced by a bell-crank 138 a proximal end of which is fixed to the support 44, and the bent part of which is articulated about an oscillation axis 137 to an intermediate part 92 which is integral with the sliding rod 17 of the consolidation apparatus 2.

There is thus in this example, starting from the needles 47, a kinematic linkage comprising firstly a rotation about the oscillation axis 137, followed by a sliding, namely the sliding of the rod 17 in a guide integral with the frame. In other words, there is between the needles 47 and the frame a part, the rod 17, which is linked to the needles 47 by a rotation means and which is linked to the frame by a sliding means.

The distal end of the crank 138 is articulated about a positioning axis 156 to the small end 93 of a connecting rod 94 the big end 96 of which is articulated to the eccentrated journal 97 of an eccentric shaft 98 which is rotatably mounted relative to the frame 19 and driven at the same rotation speed as the eccentric shaft 31 of the apparatus 2. The eccentricity radius 161b of the eccentric shaft 98 lags relative to the eccentricity radius 161a of the eccentric shaft 31, which actuates the oscillation axis 137 via the connecting rod 127 and the rod 17. Thus, when the consolidation needles 23 are in maximum-penetration position, the eccentric shaft 98 will carry out a part of its stroke in which it will push the small end of connecting rod 93 further downwards and therefore cause the bell crank 138 to pivot in anti-clockwise direction in FIG. 6. This results in the component of movement as indicated by the arrow 91a when the pre-needling needles 47 are substantially in a substantially maximum-penetration position.

This embodiment reduces the distance between the pre-needling needles 47 and the entry of the fleece between the table 24 and the stripper plate 26 of the needling apparatus 2. On the other hand it does not allow the penetration phases of the needles 23 to be alternated with those of the pre-needling needles 47, or to give the pre-needling needles 47 a strike rate which would be different from that of the consolidation needles 23.

The example of FIG. 7 will be described only where it differs from that of FIGS. 1 to 5.

In the example of FIGS. 1 to 5, the pre-needling apparatus 3 and the consolidation apparatus 2 are situated on the same side of the path 1 of the fleece. In the example of FIG. 7, the needling apparatus 2 is situated on one side of the path 1, in the example the upper side, and the pre-needling apparatus 3 is situated on the other side of the path 1, in the example the lower side. In a manner not shown, this allows, like the example of FIG. 6, the pre-needling needles 47 to be brought close to the entrance to the consolidation apparatus 2. But with the solution of FIG. 7, it is possible to enjoy this advantage while still being able to choose the solution where the penetration phases of the consolidation needles 23 alternate with those of the pre-needling needles 47 with an identical strike rate, or also the solution of different strike rates.

The more particular example of FIG. 7 diagrammatically shows a programmable control 201 and bidirectional links 202, 203, 204 and 207 between this control 201 on the one hand, and respectively a servomotor (not shown) for driving the eccentric shaft 31 of the needling apparatus 2, a servomotor (not shown) for driving one 48a of the eccentric shafts of the pre-needling apparatus 3, a servomotor (not shown) for driving the cylinders 82 of the feed apparatus 4, and a servomotor (not shown) for driving the cylinders 8 of the extractor apparatus 7. The cylinder 68 can be driven by a servomotor linked by another bidirectional line to the programmable control 201, or also be actuated via a transmission device from the servomotor actuating the cylinders 82 of the feed apparatus 4. In a manner known per se, such a structure is capable of managing at any given moment the angular position of all the motor shafts that it controls, thus consequently their respective speed during each incremental period. See on this subject U.S. Pat. No. 5,636,420.

The control can be programmed by the user in order to define, before each individual production step, the strike rates of the two apparatuses 2, 3, their mutual setting if the ratio of the rates is a rational number (resulting from the division of two integers, one by the other), the law governing the velocity of the feed apparatus and that of the extractor apparatus.

The control 201 can also be programmed then operate to provide other functions such as for example the adjustments 79 and 81 of FIG. 5, using respective servomotors. Finally, the control 201 can form part of a control assembly managing other elements of the production line, or even the whole line, from the carding at the start of the line to the reeling at the end of the line.

The example in FIG. 8 will be described only where it differs from that of FIG. 7. The table 124 and the stripper plate 126 of the needling apparatus 2 are extended upstream in order to constitute, respectively, the stripper plate and the pre-needling table of the pre-needling apparatus 3. The stripper plate 63 and the support means 62 of the pre-needling apparatus 3 of the previous desvibed drawings figures are omitted. The feed apparatus 4 opens directly between the two plates 123 and 126 which have, for the pre-needling needles 47, slots 167, 173 elongated parallel to the direction of progression 6 of the fleece (not shown), in order to allow the needles 47 to carry out their movement component which is parallel to the direction of progressive movement of the fleece.

In this solution, the working zone of the pre-needling needles is brought closest to the consolidation zone. Moreover, the means which guide the fleece between the pre-needling apparatus 3 and the consolidation apparatus 2 are fully continuous.

The drive of the pre-needling mechanism 3 can be linked by a mechanical transmission to the eccentric shaft 31 of the consolidation apparatus 2, so that the strike rates are in a specific ratio; alternatively, the two apparatuses can be controlled by servomotors and a programmable control unit as described with reference to FIG. 7.

In yet another modified embodiment, not shown, the pre-needling mechanism of FIG. 8 could be replaced by a structure similar to that of FIG. 6. Starting from the needling apparatus 2 and more particularly from the rod 17, the intermediate part 92 would be extended on either side of the fleece in order to contribute to the drive of the positioning axis such as 156a (FIG. 6), now situated on the other side of the fleece. An advantage compared with the embodiment of FIG. 6 would then be that the penetration phases of the pre-needling needles 47 would correspond to the withdrawal phases of the needling needles 23, and vice-versa.

Of course, the invention is not limited to the examples described and shown. The solution of the programmable control 201 (FIG. 7) can for example be used in an architecture such as that of FIGS. 1 to 5 where the belt 89 would then be omitted or retained.

The needling apparatus can comprise several modules, in particular at least one module on each side of the fleece, in order to needle the fleece from each of its two faces.

The support means for the fleece on the side opposite the pre-needling needles could be stationary instead of accompanying the progressive movement of the fleece. It could in particular comprise longitudinal strips which are stationary instead of turning.

The invention can be used when the consolidation is of a type other than a mechanical needling. It can for example be needling by water jet, sewing, impregnation, heat or chemical treatment etc.

In the pre-needling mechanism of FIG. 5, the two positioning axes 56a and 56b could be merged.

Claims

1- A method of processing a fleece in a pre-needling apparatus (3) and then in a consolidation apparatus (2), wherein pre-needling needles (47) are caused to carry out a combined movement comprising a reciprocation transversely to a plane (1) of the fleece (41) and a progressive movement in a direction (6) of progression of the fleece (41) when the needles (47) are in penetration phase in the fleece (41), characterized in that the progressive movement of the pre-needling needles (47) is used to impart to the fleece (41) a movement promoting introduction into the consolidation apparatus (2).

2- A method according to claim 1, characterized in that the fleece (41) is directly passed from the pre-needling apparatus (3) to the consolidation apparatus (2).

3- A method according to claim 1, characterized in that the pre-needling and the consolidation are carried out in a same machine.

4- A method according to claim 1, characterized in that during said combined movement, the penetration recirpocation is slowed down in the vicinity of a maximum-penetration position of the pre-needling needles (47) and during this slowing down a substantial part of the progressive movement in the direction (6) of progression of the fleece (41) is carried out.

5- A method according to claim 1, characterized in that the consolidation is carried out in the form of a needling imparting an essentially linear reciprocating movement to needling needles (23).

6- A method according to claim 5, characterized in that the pre-needling is carried out only from a first face of the fleece (41), and the needling is carried out starting with needles (23) penetrating into the fleece (41) through a face thereof opposite the first face.

7- A method according to claim 1, characterized in that the amplitude of the progressive movement of the pre-needling needles (47) is adjusted.

8- A method according to claim 7, characterized in that the amplitude of the progressive movement is adjusted so that the progression of the needles (47) during the penetration phase substantially corresponds to the progression of the fleece (41) during said phase.

9- A method according to claim 5, characterized in that, between the pre-needling cycle and the needling cycle, a cycle setting is defined such that the needling needles (23) are in penetration phase when the pre-needling needles (47) are in withdrawal phase, and the needling needles (23) are in withdrawal phase when the pre-needling needles (47) are in penetration phase.

10- A method according to claim 5, characterized in that the pre-needling is carried out at a slower strike rate than that of the needling.

11- A method according to claim 5, characterized in that the fleece (41) is driven at a speed which is lower when the pre-needling needles (47) are in withdrawal phase and higher when the pre-needling needles (47) are in penetration phase.

12- An installation for processing a fibre fleece, for implementation of a method according to claim 1, comprising, along a path (1) for the fibre fleece (41), a pre-needling apparatus (3) followed by a consolidation apparatus (2), the pre-needling apparatus (3) comprising means for imparting to pre-needling needles (47) a combined movement comprising a penetration reciprocation transversely to the plane of the path (1) of the fleece and a progression reciprocation substantially parallel to the direction (6) of the progressive movement of the fleece (41), characterized in that an exit from the pre-needling apparatus (3) and an entrance into the consolidation apparatus (2) are in a relationship such as to preserve the progressive movement of the fleece (41).

13- An installation according to claim 12, characterized in that the exit from the pre-needling apparatus (3) and the entrance into the consolidation apparatus (2) are directly linked.

14- An installation according to claim 12, characterized in that the pre-needling apparatus (3) is installed between a feed apparatus (4) mounted upstream, propelling the fleece (41) by friction, and the consolidation apparatus (2).

15- An installation according to claim 12, characterized in that the pre-needling apparatus (3) and the consolidation apparatus (2) are installed in a same machine.

16- An installation according to claim 12, characterized in that the consolidation apparatus (2) comprises actuating means for giving consolidation needles (23) an essentially linear reciprocating movement transverse to the plane of the path (1) of the fleece (41).

17- An installation according to claim 16, characterized in that said installation comprises actuating means common to the pre-needling needles (47) and the consolidation needles (23).

18- An installation according to claim 16, characterized in that said installation comprises means (89; 92) for giving the pre-needling needles (47) and the consolidation needles (23) the same strike rate.

19- An installation according to claim 16, characterized in that said installation comprises means for defining a cycle setting between the movement of the pre-needling needles (47) and the movement of the consolidation needles (23).

20- An installation according to claim 19, characterized in that the means for defining a cycle setting are adjustable.

21- An installation according to claim 19, characterized in that the cycle setting is such that the pre-needling needles (47) are in a withdrawal phase when the consolidation needles (23) are in a penetration phase, and the pre-needling needles (47) are in a penetration phase when the consolidation needles (23) are in a withdrawal phase.

22- An installation according to claim 16, characterized in that said installation comprises means (89a; 201) for giving the pre-needling needles (47) a strike rate different from that of the consolidation needles (23).

23- An installation according to claim 16, characterized in that said installation comprises means (201) for adjusting the strike rate of the pre-needling needles (47) relative to that of the consolidation needles (23).

24- An installation according to claim 12, characterized in that said installation comprises means of propulsion (4, 7) of the fleece (41) by friction which are actuated at a greater speed when the pre-needling needles (47) are in penetration phase than when the pre-needling needles (47) are in withdrawal phase.

25- An installation according to claim 12, characterized in that the pre-needling apparatus (3) comprises, between the path (1) of the fleece (41) and a support (44) for the needles, a stripper plate (63; 126) provided with orifices (67; 167) through which the needles (47) pass, these orifices having, parallel to the direction of progression of the fleece (41), a sufficient dimension to allow the progression component of the movement of the needles (47).

26- An installation according to claim 25, characterized in that a needling table (124) of the consolidation apparatus (2) is an integral extension of said stripper plate.

27- An installation according to claim 12, characterized in that the pre-needling apparatus (3) comprises a support means (68) that can move with the fleece, which delimits the path (1) of the fleece (41) on the side opposite the pre-needling needles (47).

28- An installation according to claim 27, characterized in that the support means is a rotating roller (68) having recesses (73) for the needle tips (47).

29- An installation according to claim 28, characterized in that the recesses (73) are gaps between annular ribs (72).

30- An installation according to claim 12, characterized in that the pre-needling apparatus (3) comprises, for delimiting the path (1) of the fleece (41) on the side opposite the pre-needling needles (47): support ribs (72) in planes parallel to the direction of progression of the fleece (41); and between the ribs (72), recesses for receiving the needle tips (47).

31- An installation according to claim 29, characterized in that the bottoms of the recesses (72) are formed by fingers (74) which extend beyond the ribs (72) in a direction towards the consolidation apparatus (2).

32- An installation according to claim 12, characterized in that the pre-needling apparatus (3) is mounted so that the pre-needling needles (47) penetrate the fleece through a first face of the fleece (41) and the consolidation apparatus (2) comprises consolidation needles (23) which penetrate through a second face opposite the first face of the fleece (41) as resulting from the pre-needling.

33- An installation according to claim 12, characterized in that the pre-needling apparatus comprises a movable structure (36, 136) intended to carry needles (47), and an actuating mechanism for imparting to the needles (47) an elliptical-type movement having a penetration component and a progression component, and in that one of the components, preferably the progression component, is at least to a large extent generated by angular oscillation of the movable structure.

34- An installation according to claim 33, characterized in that the movable structure (36, 136) is guided relative to a frame of the machine by a functional chain comprising a sliding in series with an articulation about an oscillation axis (37, 137) parallel to the width of the fibre fleece.

35- An installation according to claim 34, characterized in that the sliding and the articulation are carried out by means situated one inside the other.

36- An installation according to claim 34, characterized in that the movable structure (36) is slidingly guided in a guide (39) mounted for oscillation in said articulation.

37- An installation according to claim 34, characterized in that the actuating mechanism comprises two crank connecting-rod systems, each system comprising a connecting rod (51a, 51b) a small end of which (54a, 54b) is articulated to said movable structure (36) about a so-called positioning axis (56a,56b) parallel to said oscillation axis (37).

38- An installation according to claim 37, characterized in that the two crank connecting-rod systems are similar and capable of a mutual phase shift, one being situated in front of and the other behind the positioning axis (56a, 56b), relative to the direction (6) of progression of the fleece.

39- An installation according to claim 37, characterized in that there is a respective positioning axis (56a, 56b) for each of the two crank connecting-rod systems.

40- An installation according to claim 39, characterized in that the two positioning axes (56a, 56b) are very close to each other.

41- An installation according to claim 37, characterized in that the two connecting rods (51a, 51b) are oriented with their connecting-rod small end (54a, 54b) pointing in a direction generally away from the plane (1) of the fleece (41).

42- An installation according to claim 37, characterized in that the oscillation axis (37) is placed substancially between two eccentric means (48a, 48b) turning in mutually opposite directions and each forming part of a respective one of the two crank-connecting-rod systems.

43- An installation according to claim 34, characterized in that the movable structure (136) is articulated by said articulation to a slider (17) actuated by a first reciprocation generator, in particular a crank connecting-rod system (31, 127) generating one of the components, preferably the penetration component, and the movable structure (136) is moreover articulated about a positioning axis (156) to a second crank-connecting-rod system (94, 98) generating said angular oscillation of the movable structure (136) about said articulation of the slider (17).

44- An installation according to claim 12, characterized in that said installation comprises: means (79) for adjusting the depth of penetration of the pre-needling needles in the path of the fleece (41); means (57) for adjusting the amplitude of the progression component of the movement of the pre-needling needles (47); means (201) for adjusting a progression pitch of the fleece for each operating cycle of the pre-needling needles.