EP0517563B2 - Cross-lapper - Google Patents

Abstract

PCT No. PCT/FR92/00461 Sec. 371 Date Feb. 1, 1993 Sec. 102(e) Date Feb. 1, 1993 PCT Filed May 22, 1991 PCT Pub. No. WO92/21799 PCT Pub. Date Dec. 10, 1992.A web of fibers (4) is conveyed by conveyor-belts (2, 5) which pass around rollers. A number of rollers are carried by an input carriage (10) and an output carriage (14), said carriages being capable of displacement in reciprocating motion above an apron (8) which moves in a direction parallel to the axes of the rollers and collects the web (4) in the form of a lap (6). A guide roller (34) defines for the web (4) on a first conveyor-belt (2) a section (22) which is inclined towards the pinching line and is located upstream of said line, said pinching line being defined by two adjacent rollers (35, 61). The pinching roller (35) associated with the first conveyor-belt (2) causes it to make a turn through an angle (B) within the range of 90 degrees to 180 degrees. The pinching line is located in an intermediate angular position between the beginning and the end of said turn. The invention is applicable to the manufacture of nonwoven fabrics.

Description

The present invention relates to a spreader lapper to transform by folding a veil into a tablecloth.

We know for example from the FR - B - 2,553,102 such a machine in which a web from of a card, is first transported by a first mat, said front carpet, up to a pinch area where it is held between the first and second carpet and transported to an exit cart. The back and forth of exit cart above a receiving apron causes a deposit of the veil which it delivers, by folds alternated, accordion-style, on the apron. Like the apron moves in a direction parallel to the axes of guide rollers carried by the output carriage, the successive folds are shifted along this direction and the veil forms a continuous sheet on the apron whose side edges are defined by the folds. The start of the nip is defined in position movable by an entry carriage which performs a movement back and forth to make speed compatible of admission of the veil in the spreader and the speed of unwinding of the web by the exit carriage despite the back and forth movements of the latter. So the veil, which is fragile in constitution is not disturbed by piling up, neither by stretching, nor by friction.

In machines of this kind, keep constant despite back and forth movements carts, the developed length of the routes closed followed by carpets.

In some realizations, the back and forth of the input carriage is compensated for by the back and forth movement of the exit trolley and vice versa thanks to an arrangement guide rollers (see for example FR - B - 2 553 102).

In other realizations (see FR-B- 2 234 395 or US-A- 1 886 919) are provided with auxiliary carriages which also perform back and forth movements in translation to selectively lengthen or shorten the mat outside the pinch area and compensate as well variations in the length of the pinch area.

In general, the front carpet, in the area where it is in contact with the veil, makes a 180 turn degrees around one or more guide rollers carried by the entry cart. The veil undergoes an acceleration centrifugal when making this 180 degree turn. In as a result, it tends to come off the front carpet at level of the entry trolley. This trend is still reinforced when the input trolley due to its back and forth movement, at a speed of movement of opposite direction to that of the speed of admission of the veil upstream. These detachments cause air pockets between the veil and the carpets in the curved regions of transport route. The veil, made up of an assembly light fiber, may then disperse, which adversely affects the homogeneity of the sheet formed. In addition, detachments can cause jams, obviously undesirable, in the pinch area of the sail. This drawback is particularly noticeable in the structure according to US-A- 1 886 919, where the turn to 180 degrees is performed without any outside support.

In some realizations, such as that shown in the drawings of FR-B- 2 553 102, which constitute the closest state of the art, the shift to 180 degrees the front mat performs on the cart input is divided into two successive 90 degree turns each performed around a respective guide roller, which creates a substantial sail transport section vertical between these two rollers. The second carpet says rear carpet, also has a substantially section vertical, delimited by two superimposed guide rollers mounted on the entry carriage, and adjacent to the section vertical of the front carpet. Pinch area has so a vertical region defined by the sections vertical adjacent front and rear belts. Has relatively high speeds, precise guidance without jerks of the veil in this vertical region becomes very delicate, especially because of the vibrations of the carpets in their respective vertical sections. This drawback can be reduced by reducing the length of these sections vertical but this requires reducing the radius of curvature guide rollers which delimit them. But we avoid usually make the carpets take turns small radius of curvature because such bends influence unfavorably their mechanical behavior.

The previous ASSELIN spreader-topper type 350FP or 360FP, which is the closest state of the art, or an embodiment described in a previous unpublished application WO-A-91 15 618, repeat the arrangement described in FR-B-2 553 102 except that the rollers of the carriage that guide the front carpet define for the veil an inclined section ending at the pinch line constituting the beginning of the pinch zone. This reduces the harmful effects, described above, of the 180 ° turn of the veil in the entry carriage because the turn is broken down into two turns like according to FR-B-2 553 102, but without resulting in a floating zone of the sailing between the two turns. One of the turns is more than 90 °, but it is itself almost divided in two by the pinch line, which is in intermediate part between the beginning and the end of the turn. Furthermore, these spreader-lappers known or described previously include a pinching zone long, made up of two rectilinear sections separated by a bend according to a angle close to 180 °.

One of the aims of the present invention is to propose a new spreader-lapper in which the stability of the veil transport is improved.

The invention thus proposes a spreader-lapper to transform by folding a veil into a tablecloth, comprising two belts each following a path closed and associated with rollers for their guidance and training respective, the closed paths being external to each other and adjacent to each other the other in a nip area delimited by guide rollers carried by an input carriage and an output carriage movable in translation along a horizontal direction and perpendicular to the axes of the rollers, the rollers of guide comprising two pinch rollers each associated with one of the belts and around which the carpets define a pinch line between them constituting a beginning of the pinching zone, means for bringing the veil to the entrance to the nip, an apron movable in a parallel direction to the axes of the rollers and receiving the veil at its exit from the nip, drive means for applying translational movements in back and forth to the input cart and the output cart, and means for defining for the veil on a first of the carpets and upstream of the nip line a section inclined towards the nip line, the nip roller associated with the first carpet causing the first carpet to turn at an angle greater than 90 ° and less than 180 °, the nip line being located in position angular intermediate between the beginning and the end of this turn.

According to the invention, the spreader-lapper is characterized in that it further includes auxiliary trolleys movable in translation perpendicular to the axes of the rollers to substantially maintain constant the length of each of the closed paths, and in that the area of nip is formed between the input and output carriages by a section substantially horizontal rectilinear.

With the machine according to the invention, the stability of the veil transport is excellent even at high operating speeds.

According to a preferred embodiment of the invention, the veil transported to the entry carriage passes first between the two carpets tightened by the rollers pinch, whose axes are preferably located substantially in the same horizontal plane.

At the pinch line, the rear mat is thus opposed to the veil separating from the front carpet. Thanks to the tilt upstream of the nip, the turn to be made is less than 180 degrees. In addition, this turn is sort of split by the line of pinching which, at a certain stage of the turn, prevents positively any detachment of the veil compared to the first carpet. So we are brought back to two corners elementaries of fairly small angle, and performed on a single pinch roller. This can have a relatively large radius, which further reduces the centrifugal force. This ensures precise transport and little disturbance of the veil in the vicinity of the entry carriage in reducing the likelihood of air pockets forming under the veil in the area immediately upstream of the line pinch.

• la figure 1 est une vue extérieure en perspective d'un étaleur-nappeur ;
• les figures 2 à 4 sont des vues schématiques en élévation d'un étaleur-nappeur conforme à l'invention dans trois positions différentes ;
• la figure 5 est une vue en élévation à plus grande échelle représentant avec davantage de détail le chariot d'entrée de l'étaleur-nappeur des figures 2 à 4 ;
• la figure 6 est une vue en plan prise selon le plan VI-VI indiqué aux figures 4 et 7 ; et
• la figure 7 est une vue en plan partielle prise selon le plan VII-VII indiqué aux figures 4 et 6 ;
• la figure 8 est une vue analogue à la figure 5 montrant le chariot de sortie de l'étaleur-nappeur.

Other features and advantages of the present invention will appear in the detailed description below of an exemplary embodiment. In the accompanying drawings:

• Figure 1 is an external perspective view of a spreader-lapper;
• Figures 2 to 4 are schematic elevational views of a spreader-lapper according to the invention in three different positions;
• Figure 5 is an elevational view on a larger scale showing in more detail the input carriage of the spreader-lapper of Figures 2 to 4;
• Figure 6 is a plan view taken along the plane VI-VI shown in Figures 4 and 7; and
• Figure 7 is a partial plan view taken along the plane VII-VII shown in Figures 4 and 6;
• Figure 8 is a view similar to Figure 5 showing the output carriage of the spreader-lapper.

The spreader-topper shown in perspective at the Figure 1 includes a first carpet 2, said front carpet which collects the veil of fibers 4, for example from a card not shown, and transports it to enclosure 1 where it is transformed by folding into a tablecloth 6 transported by an apron 8 outside the enclosure 1. The apron 8 transports the formed sheet 6, for example to a needling machine not shown. The senses of transport of the web 4 and the web 6 are respectively indicated in Figure 1 by the arrows F and K. For the purposes reference, we will call "front side" of the spreader-lapper side 7 adjacent to the side through which penetrates the veil 4 and "rear side" of the spreader-lapper the side 9 opposite the front side 7.

The interior of the spreader-lapper is shown schematically in the elevation views of Figures 2 to 4, taken along a plane Q perpendicular to the direction for transporting the ply 6 by the deck 8.

Associated with the front mat 2, the spreader-lapper includes a second mat 5, said rear mat. Carpets 2 and 5, shown in solid lines in FIGS. 2 to 4, have the same width and have their side edges in the same planes parallel to the plane of figures 2 to 4. The front carpet 2 follows a closed path consisting of sections 20 to 31 delimited by cylindrical guide rollers 32 to 43. The rear carpet 5 follows a closed path consisting of sections 50 to 59 delimited by guide rollers cylindrical 60 to 69.

The guide rollers 32 to 43, 60 to 69 are pivotally mounted around respective perpendicular axes in the plane of FIGS. 2 to 4, that is to say parallel to the direction of movement of the deck 8. The axes of the rollers 32, 33, 39, 40, 42, 43 and 65, 66, 68, 69 are fixed by compared to chassis 1 of the spreader-lapper. The axes of rollers 34, 35 and 60, 61, 62, 63 are carried by a first movable main carriage 10, said entry carriage. The axes of the rollers 36, 37, 38 and 64 are carried by a second movable main carriage 14, said outlet carriage, and those of rollers 41 and 67 are carried by carriages auxiliaries 16, 18.

For each closed journey 20 to 31, 50 to 59 of mat, a mobile auxiliary carriage 16, 18 carries a guide roller 41, 67 around which this closed path performs a 180 degree turn. The two carts auxiliaries 16, 18 have movements which compensate for those main carriages 10, 14 to maintain substantially constant the length of each of the closed paths 20 to 31, 50 to 59.

For each carpet 2, 5, at least one of fixed axis rollers (e.g. numbered rollers 39 and 65 respectively) is rotated by known means not shown so as to circulate the belts 2, 5 along their respective closed paths 20 to 31, 50 to 59 according to kinematic laws predetermined. The directions of movement of the belts 2, 5 are indicated respectively by the arrows F2, F5 aux Figures 2 to 4.

The closed routes 20 to 31, 50 to 59 are external to each other and adjacent to each other in a nip in which the carpet sections in movement numbered 23 and 53 in Figures 2 to 5 are located one against the other so as to pinch the veil 4 between them. Veil 4 is shown in dotted lines at the Figure 4 but is not shown in Figures 2 and 3 for show the superimposition of the carpet sections 23, 53.

The adjacent horizontal sections 23, 53 of the closed paths followed by the two belts 2, 5 in the area are pinned, at the entrance to the nipping, by guide rollers 35, 61 carried by the entry carriage 10, and, at the exit from the nipping, by guide rollers 38, 64 carried by the output carriage 14.

The main carriages 10, 14 are located above of the deck 8 and are movable in translation alternate in a horizontal direction and perpendicular to the axes of the rollers 32 to 43, 60 to 69.

Entrance cart 10 (see also view more detailed in Figure 5) carries two guide rollers 34, 35 for the front carpet 2 and located inside its closed path 20 to 31. Upstream of the entry carriage 10, the front belt 2 carrying the veil 4 follows the section substantially horizontal 21 coming from the front side 7. On reaching the entry carriage 10, the front belt 2 describes a first turn around the idler roller 34 at an angle A between O and 90 degrees oriented down to form the inclined section 22, then a second turn around the roller 35 at an angle B between 90 and 180 degrees to constitute the section horizontal 23 of the nip, directed to the side before 7 of the spreader-lapper. Angular deviation total A + B of the front belt 2 around the rollers guide 34, 35 carried by the input carriage 10 is equal 180 degrees.

The input carriage 10 further carries four guide rollers 60, 61, 62, 63 relative to the belt rear 5, the rollers 60, 61, and 63 being internal to its closed path 50 to 59 and the roller 62, larger radius, called detour roller, being outside this path closed 50 to 59. Upstream of the entry carriage 10, the conveyor belt rear 5, which does not wear the veil 4, follows the section substantially horizontal 59 from the rear side 9. On reaching the entry carriage 10, the mat rear 5 describes a first turn around the roll of reference 60 at an angle C between 0 and 90 degrees, facing down to enter section 50, then a second 180 degree turn around roller 61 to enter section 51, then a third turn around of the detour roller 62 at a negative angle (because the detour roller 62 is outside the closed path 50 to 59) greater than 180 degrees, and finally a fourth turn around the roller 63 to enter the section horizontal 53 of the nip, directed to the side before 7 of the spreader-lapper. Angular deviation total of the rear belt 5 around the guide rollers 60, 61, 62, 63 carried by the input carriage 10 is nothing.

We see in Figure 5 that the two belts 2, 5, as well as the veil 4 passing between them, are pinched along a pinch line defined between the two rollers 35, 61 and constituting the entrance to the pinching. These two pinch rollers 35, 61 have their respective axes located in the same horizontal plane P. En bypassing roller 63, located on the input carriage 10 below the horizontal plane P, the rear belt 5 is supported and tangentially joined the front mat 2 in the pinch area 23, 53. The web 4 engages in the nip 23, 53 after being transported on the sections 20, 21, 22 of the path of the front belt 2 and be passed between the belts 2, 5 pinched between the rollers 35, 61 along the nip line. These pinch rollers 35, 61 can be resiliently pushed towards each other the other by known return means (not shown).

The entry carriage 10 comprises two sides 11 located on either side of the rollers 34, 35, 60, 61, 62, 63 he's wearing. These rollers 34, 35, 60, 61, 62, 63 have their respective axes fixed at their ends on the sidewalls 11. On their face opposite to the rollers 34, 35, 60, 61, 62, 63, the sides 11 of the input carriage 10 carry wheels 13 pivoting about a horizontal axis and placed on a horizontal lateral ramp 12 secured to the chassis 1 of the spreader-lapper, so as to guide the input carriage 10 in its translational movement. A similar structure, visible in Figure 8, is provided for guide the exit carriage 14 in its movement of translation.

At the exit of the pinch zone 23, 53, the two belts 2, 5 pass between two pinch rollers debtors 38, 64 carried by the output carriage 14 (see Figures 2 to 4 and 8). These two supply rollers 38, 64 have their respective axes in the same horizontal plane located above the deck 8.

Around the pinch roller 64, the mat rear 5 makes a 180 degree turn to go from horizontal section 53 belonging to the nip zone at a horizontal section 54 extending immediately above of the apron 8. This horizontal section 54 passes under the input carriage 10 to join a roll of fixed axis guide 65 located on the rear side 9 of the spreader-lapper.

In addition to pinch roller 38, the carriage output 14 carries two guide rollers 36, 37 (figure 8) relating to the front belt 2. At the end of the section horizontal 23 belonging to the pinch zone, the mat before 2 describes a first turn around the roll of reference 36 at an angle between 0 and 30 degrees oriented upwards to enter section 24, then a second turn around the detour roller 37, located at the outside of its closed path 20 to 31, at an angle negative greater than 180 degrees to enter the stretch horizontal 25, and finally a third 180 degree turn around the pinch roller 38 to enter the horizontal section 26 extending immediately above of apron 8 to join an axis guide roller fixed 39 located on the front side 7 of the spreader-lapper. The total deviation of the front belt 2 around the rollers of guide 36, 37, 38 carried by the output carriage 14 is nothing.

The auxiliary carriages 16, 18 are movable in translation in a horizontal direction and perpendicular to the axes of the rollers 32 to 43, 60 to 69. The auxiliary carriages 16, 18 are located in a lower passage 70 extending under the apron 8, at distance from the zones where veil 4 and the web pass formed 6. The lower passage 70 is separated from the deck 8 by a horizontal partition 72.

The auxiliary carriage 16 is provided for keep the length of the closed path constant 20 to 31 followed by the front belt 2. It carries a guide roller 41 around which the front carpet 2 turns 180 degrees. The front mat 2 is guided between the carriages main 10, 14 and the auxiliary carriage 16 by fixed axis guide rollers 32, 33, 39, 40, 42, 43 located on the front side 7 of the spreader-lapper.

The auxiliary carriage 18 is provided for keep the length of the closed path constant 50 to 59 followed by the rear carpet 5. It carries a roll of guide 67 around which the rear belt 5 performs a 180 degree turn. The rear carpet 5 is guided between the main carriages 10, 14 and the auxiliary car 18 by fixed axis guide rollers 65, 66, 68, 69 located on the rear side 9 of the spreader-lapper.

Each auxiliary carriage 16, 18 comprises two sides 74, 78 located on either side of the roller 41, 67 he wears (see Figures 6 and 7). Each of these rolls 41, 67 has its axis carried at its ends on the sides 74, 78 of the respective auxiliary carriage 16, 18. On their face opposite the roller 41, 67, the flanks 74, 78 carry wheels 75, 79 pivoting about a horizontal axis and which roll on horizontal side rails 76, 80 integral with the chassis 1 of the spreader-lapper so as to guide the auxiliary carriages 16, 18 in their translational movements. Side rails 76, 80 extend inside the underpass 70 and other of the rollers 41, 67. As can be seen from the view partial of figure 7, they are located at heights different. In the example shown, the rails lower 76 support the auxiliary carriage 16 guiding the front belt 2 and the upper rails 80 support the auxiliary carriage 18 guiding the rear belt 5. Above wheels 79 of the carriage 18 placed on the rails upper 80 extend from side angles 82 integral with the chassis 1 and forming a support for the partition 72 which delimits the upper part of passage 70.

To drive the main carriages 10, 14 and auxiliaries 16, 18, the spreader-lapper comprises pinions motors 85, 89 rotated by means not represented and meshing respectively on belts notches 84, 88 symbolically represented in dashes with Figures 2 to 4.

Two notched belts 84 extend on either side other rollers and mats between the carriage input 10 and the auxiliary carriage 16, passing from rear side 9 of the spreader-lapper. Between the carriages 10 and 16 to which they are fixed by their ends the toothed belts 84 each bypass two sprockets gear 85, 86 (including motor pinion 85) pivoting respectively around a fixed axis parallel to the axes of rollers 32 to 43, 60 to 69. The pinions 85, 86 are arranged so that the end sections of the toothed belts 84 are parallel to the direction of translation of the carriages 10, 16 to which they are respectively fixed.

Likewise, two toothed belts 88 extend on either side of the rollers and belts between the exit carriage 14 and auxiliary carriage 18, in passing from the front side 7 of the spreader-lapper. Between the carriages 14 and 18 to which they are fixed by their ends, the toothed belts 88 each bypass two idler gears 89, 90 (including the motor gear 89) pivoting respectively around a fixed axis parallel to axes of the rollers 32 to 43, 60 to 69. The pinions 89, 90 are arranged so that the end sections of the toothed belts 88 are parallel to the direction of translation of the carriages 14, 18 to which they are respectively fixed.

In addition, the main carriages 10, 14 and auxiliaries 16, 18 are coupled in pairs 10, 16 and 14, 18 by means of cables 92, 96 represented symbolically in dashed lines in Figures 2 to 4. These cables 92, 96 are less stretchy than mats 2, 5.

Two cables 92 extend on either side of the rollers and mats between the input carriage 10 and its associated auxiliary carriage 16, passing from the front side 7 of the spreader-lapper. Between carriages 10 and 16 to which they are fixed by their ends, the cables 92 each bypass two deflection pulleys 93, 94 respectively around a fixed axis parallel to the axes of rollers 32 to 43, 60 to 69. The pulleys 93, 94 are arranged so that the end sections of the cables 92 are parallel to the direction of translation of the carriages 10, 16 to which they are respectively fixed.

Two cables 96 extend on either side of the rollers and belts between the output carriage 14 and its associated auxiliary carriage 18, passing from the rear side 9 of the spreader-lapper. Between carriages 14 and 18 to which they are attached by their ends, the cables 96 each bypass two idler pulleys 97, 98 pivoting respectively around a fixed axis parallel to axes of the rollers 32 to 43, 60 to 69. The pulleys 97, 98 are arranged so that the end sections of the cables 96 are parallel to the direction of travel carriages 14, 18 to which they are respectively fixed.

In operation, we control the drive belts 2, 5 via the driving rollers 39, 65 and that of the carriages 10, 14, 16, 18 by via the driving pinions 85, 89 meshing on the notched belts 84, 88. We thus animate the carriages 10, 14, 16, 18 of synchronous translational movements in back and forth. Kinematic laws to be applied to main carriages 10, 14 can for example be those taught by FR-B- 2 234 395.

The extreme positions of the back and forth movements are shown schematically in Figures 2 and 3 and an intermediate position in FIG. 4.

If we denote by L the width of the sheet formed 6, the output carriage 14 and its carriage associated auxiliary 18 follow back and forth movements amplitude L performed with velocities snapshots with the same values and opposite directions, so that the length of the closed path 50 to 59 relative at the rear carpet 5 is kept constant. Carriage input 10 and its associated auxiliary carriage 16 follow back and forth movements of amplitude of the order of L / 2 carried out with instantaneous speeds having the same values and opposite directions, so the length of closed path 20 to 31 relative to front belt 2 is kept constant.

These kinematic relationships between carriages associated are obtained by cables 92, 96 which mate. In a first phase of the back-and-forth movement going from the position illustrated in figure 2 to that illustrated in FIG. 3, the driving pinions 85, 89 are driven in the direction indicated by the arrows G at the figure 2. The toothed belts 84 then pull the input carriage 10 to the rear side 9 and the toothed belts 88 pull the auxiliary carriage 18 towards the front side 7. A pulling force towards the front side 7 is transmitted to the auxiliary carriage 16 by via cable 92 which couples it to the carriage input 10. Tractive effort towards the rear side 9 is transmitted to the output carriage 14 via cable 96 which couples it to the auxiliary carriage 18.

Symmetrically, in the second phase of the back and forth movement from the illustrated position to Figure 3 to that illustrated in Figure 2, the gables motors 85, 89 are driven in the direction indicated by the arrows H in Figure 3. The toothed belts 84 pull then the auxiliary carriage 16 towards the rear side 9 and the toothed belts 88 pull the output carriage 14 towards the front side 7. A pulling force towards the side before 7 is transmitted to the input carriage 10 by via cable 92 which couples it to the carriage auxiliary 16. A pulling force towards the rear side 9 is transmitted to the auxiliary carriage 18 by via cable 96 which couples it to the exit 14.

The tensile forces mentioned, useful for synchronize the movements of the associated carriages, are advantageously absorbed by the cables 92, 96 because these are less stretchy than mats 2, 5. This provides a significant advantage over the spreader-lappers of the prior art, in which these efforts of traction are essentially absorbed by the mats. In As a result, carpets are less stressed and may be lighter in constitution while having a improved durability. The light construction of the carpets is very advantageous because it reduces the inertia of the machine and facilitates movement in the curved regions of their closed journeys, which improves the regularity of transport of veil 4 in these regions.

The web 4 from the card is placed on the inclined section 20 followed by the front belt 2 (see Figure 4). After deflection on the roller 33, it is transported horizontally on the section 21 to the input carriage 10. On this, the web 4 is first deflected by the roller 34 at the angle A between 0 and 90 degrees. The moderate value of the angle A prevents the veil from being disturbed when it is deflected by the roller 34. After being transported on the inclined section 22 of the front belt 2, the veil 4 bypasses the pinch roller 35. The pinch line defined between the rollers 35, 61 prevents the web 4 from peeling off the front belt under the action of centrifugal force. As the web 4 describes around the nip roller 35 a turn at an angle B = 180 ° - A between 90 and 180 degrees and as the nip is in an intermediate angular position along this turn, the nip between the rollers 35, 61 does not cause disturbances in the inclined section 22 preceding this nip.

If angle B was too large (180 degrees or more), we could observe, for high rates, undesirable detachments of the veil immediately in upstream of the pinch roller 35 due to deflection angular too great or to a certain sagging of the front belt 2 upstream of the pinch roller 35. If angle B was too small (90 degrees or less), the haze 4 would not be reliably transported on the section too inclined 22 preceding the pinch roller 35. The prior clamping of the web 4 between the rollers 35, 61 and the appropriate value of the angle B thus ensures the better stability of the veil transport, from which it results a tablecloth 6 of optimal quality.

In the example of embodiment described, the roller 34 deflecting the veil 4 at the angle A before the line of pinch is mounted on the input carriage 10. On will understand that the roller 34 could have its fixed axis relative to the chassis 1 of the spreader-lapper. In this cases, the angles A and B are variable, but the carriage input is lighter and roller 34 contributes to support the belt 2 upstream of the entry carriage.

After traversing the pinch zone 23, 53 the web 4 reaches the outlet carriage 14 which deposits it by alternating folds on the apron 8 to form the ply 6.

The formed ply 6 is, to a certain extent, sheltered from drafts created by back and forth movements carriages 10, 14, 16, 18 due to the presence of the carpet sections 26, 54 located immediately above the deck 8. The presence of vertical sections 27, 55 adjacent to these sections 26, 54 further contributes prevent side air currents from reaching the level of the tablecloth formed 6. Like the carts auxiliaries 16, 18 move in the underpass 70 of the spreader-lapper separated from the apron 8 by the partition 72, the air currents caused by their movements remain essentially confined within the passage lower 70, away from the areas where the veil 4 passes and the tablecloth 6. Consequently neither the veil 4 nor the tablecloth 6 are only disturbed by these drafts and homogeneity of the formed ply 6 is improved, in particular when the spreader-lapper operates at high speed.

Although, within the general framework of the invention, the auxiliary carriages can be located in separate underpasses, it is advantageous, for reduce clutter, provide a lower passage single 70 in which the two carriages move auxiliary 16, 18. Like the auxiliary carriages 16, 18 are placed on rails 76, 80 located at heights different in the underpass 70, the belts of transmission 84, 88 and coupling cables 92, 96 are also arranged at different heights, and they do not interfere in operation.

The underpass 70 has a length at least equal to 3L / 2, i.e. the sum of the amplitudes of back and forth movements of the main carriages 10, 14 (or auxiliary carriages 16, 18).

Claims (6)

1. A crosslapper for converting a web (4) to a fleece (6) by a folding operation, comprising two conveyor-belts (2, 5) which are each intended to follow a closed path (20 to 31, 50 to 59) and are associated with rollers (32 to 43, 60 to 69) for respective guiding and displacement of said conveyor belts, the closed paths (20 to 31, 50 to 59) being external to each other and adajcent to each other in a pinching zone (23, 53) delimited by guide rollers (35, 61; 38, 64) carried by an input carriage (10) and an output carriage (14) which are capable of displacement in translational motion in a horizontal direction perpendicular to the axes of the rollers (32 to 43, 60 to 69), the guide rollers comprising two pinching rollers (35, 61) which are each associated with one of the conveyor-belts and about which the conveyor-belts (2, 5) define between them a pinching line constituting a beginning of the pinching zone, means (20, 21, 22) for bringing the web (4) to the entrance of the pinching zone (23, 53), an apron (8) which is movable in a direction parallel to the axes of the rollers (32 to 43, 60 to 69) and which receives the web (4) as it passes out of the pinching zone (23, 53), driving means (84, 85, 88, 89) for applying reciprocating movements of translation to the input carriage (10) and to the output carriage (14), and means (34) for defining a section (22) for the web (4) on a first conveyor-belt (2) , said section (22) being located upstream of the pinching line and inclined towards said line, wherein the pinching roller (35) associated with the first conveyor-belt causes said first conveyor-belt (2) to make a turn through an angle (B) greater than 90 degrees and smaller than 180 degrees, and wherein the pinching line is located in an intermediate angular position between the beginning and the end of said turn, characterized in that it furthermore comprises auxiliary carriages (16, 18) capable of translational motion in a direction perpendicular to the axes of the rollers (32 to 43, 60 to 69) so as to maintain substantially constant the length of each closed path (20 to 31, 50 to 59) , and in that the pinching zone is constituted between the input and output carriages (10, 14) by a substantially horizontal rectilinear section (23, 53).
2. A crosslapper according to claim 1, characterized in that the two pinching rollers (35, 61) carried by the input carriage (10) are located substantially in the same horizontal plane (P).
3. A crosslapper according to claim 1 or 2, wherein the web (4) is conveyed on a substantially horizontal section (21) of the first closed path (20 to 31) upstream of the input carriage (10), characterized in that the downstream end of said substantially horizontal section (21) is defined by a guide roller (34) which is carried by the input carriage (10) and about which the first closed path (20 to 31) makes a turn through an angle (A) within the range of 0 to 90 degrees.
4. A crosslapper according to one of claim 1-3, characterized in that the input carriage (10) moreover carries a detour roller (62) located on the outside of the second closed path (50 to 59) and in that the second closed path (50 to 59) passes successively around the pinching roller (61) located on the inside and said detour roller (62) located on the outside of said closed path then meets the first closed path (20 to 31) tangentially so as to form the pinching zone (23, 53).
5. A crosslapper according to one of claims 1-4, characterized in that the input carriage (10) moreover carries a supporting roller (63) located on the inside of the second closed path (50 to 59) and beneath the two pinching rollers (35, 61) in order to support the second conveyor-belt (5) in the pinching zone (23, 53).
6. A crosslapper according to one of claims 1-5, characterized in that the means which define for the web (4) the section (22) which is inclined towards the pinching line comprise a roller (34) mounted on the input carriage (10).

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