EP0522893B2 - Cross-lapper - Google Patents

Abstract

A fibre web (4) is transported by belts (2, 5) passing round rollers (32 to 43, 60 to 69). Some of these rollers are carried by main carriages (10, 14) movable to and fro above an apron (8) which is displaced parallel to the axes of the rollers and which receives the web (4) in the form of a lap. Auxiliary carriages (16, 18) are provided for keeping the length of travel of the belts (2, 5) constant in spite of the to-and-fro movements of the main carriages (10, 14). Each main carriage (10, 14) is connected to an auxiliary carriage by coupling means (92, 96) which are less extendable than the belts (2, 5) and which are arranged so as to be made live under the action of the means (84, 88) for driving the carriages. The invention is used in the production of nonwovens. <IMAGE>

Description

The present invention relates to a lapper spreader 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 veil, from a card, is first transported by a first carpet, said front carpet, to an area of pinch where it is held between the first and a second mat and transported to a trolley exit. The output carriage goes back and forth of a receiving apron causes deposition of the veil that it debits, in alternating folds, in accordion, on the apron. As the apron moves in a direction parallel to the axes of the guide rollers carried by the exit carriage, successive folds are shifted along this direction and the veil forms a continuous sheet on the deck whose side edges are defined by the folds. The start of the nip is defined in position movable by an entry cart which performs a back and forth movement intended to make compatible the speed of admission of the web into the spreader and the speed of unwinding of the web by the carriage exit despite the back and forth movements of this latest. So the veil, which is fragile is not disturbed either by crowding or stretching, nor by friction.

It should be kept constant, despite the carriages back and forth the developed length of firm paths followed by the carpets.

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

In other embodiments (see FR-B- 2 234 395 or US-A- 1 886 919) are provided trolleys auxiliaries who also perform movements back and forth in translation for selectively lengthen or shorten carpets outside the pinch area and thus compensate for variations length of the pinch area.

The present application relates more particularly this second type of realization.

According to the prior art, the pinching zone comprises two horizontal sections separated by a 180 ° turn. According to FR-A-2 234 395, this turn takes place on the carriage entry. This requires, depending on the version, three auxiliary carriages connected to the main carriages, or only two auxiliary carriages, one of which is driven different speed than that of each of the main carriages, or even a single carriage auxiliary provided that it is driven at a speed different from that of each of the main carts.

This configuration is limited in speed of treatment of the veil because the path of the veil in the lapper spreader is sinuous, the carpets follow a very sinuous path and undergo strong tensile and bending stresses, masses in reciprocating motion are large and the control of auxiliary trucks is complex.

As the carpets follow winding paths at relatively high speed, their repeated tension causes some wear which generally results in an appearance cracked from their surface, to the detriment of regular and precise fiber transport constituting the veil.

The carpets are therefore replaced periodically which is expensive and immobilizes enough the machine for a long time. To resist this wear, carpets can be relatively thick, but they then move more difficult along their winding paths.

One of the aims of the present invention is to solve the above problems by offering a new rapid spreader-lapper in which the conveyor belts have a increased durability and / or less thickness.

The invention thus proposes a spreader-lapper to transform by folding a veil in a sheet, comprising at least two carpets each following a closed path and associated, for their respective guidance and training, with rollers, some are carried by two main carriages movable in translation along a horizontal direction and perpendicular to the axes of the rollers, the closed paths of carpets being exterior to each other and adjacent to each other in an area of nip bounded at an entrance to the nip by some of the rollers guidance, and at an exit from the nip area by some others of the rollers guide, carried by one of the main carriages; compensating means, comprising two auxiliary carriages movable in translation perpendicular to the axes of the rollers, to maintain the length of each of the closed paths, each closed path having a 180 ° turn around at least one guide roller carried by an auxiliary carriage; means to bring the veil to the entrance to the pinch area; a movable deck in a direction parallel to axes of the rollers and receiving the veil at its exit from the nip; and drive means for applying reciprocating translational movements to the main carriages and to the compensating means, each main carriages being connected to an auxiliary carriage by coupling means which are less extensible than the carpet and arranged to be tensioned under the action of the drive means.

According to the invention, the spreader-lapper is characterized in that the guide rollers delimiting the pinch area at the entrance thereof are carried by the other carriage main, and in that the two closed paths define the pinch zone by two adjacent horizontal sections going from said entrance to said exit from the pinching.

In a preferred version of the invention, the means for coupling an auxiliary carriage and of a main cart include at least one cable fixed at one end to the auxiliary carriage and to the other end to the main carriage, this cable being guided by pulleys between the auxiliary carriage and the main cart. This mode of mating has the advantage of a reduced bulk.

• 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 crosslapper shown in perspective at Figure 1 includes a first carpet 2, said carpet front which collects the veil of fibers 4, for example from a card not shown, and transports it in enclosure 1 where it is transformed by folding in a ply 6 transported by an apron 8 to outside the enclosure 1. The apron 8 carries the ply formed 6, for example up to a needling machine not shown. The directions of transport of veil 4 and ply 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 by which penetrates web 4 and "rear side" of the spreader-lapper side 9 opposite to front side 7.

The interior of the spreader-lapper is shown schematically on the elevation views of Figures 2 to 4, taken along a perpendicular plane Q to the direction of transport of the sheet 6 by the apron 8.

Associated with the front mat 2, the spreader-lapper includes a second mat 5, said rear mat. The belts 2 and 5, shown in solid lines in the figures 2 to 4, have the same width and have their edges lateral in the same planes parallel to the plane Figures 2 to 4. The front mat 2 follows a path closed 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 rollers cylindrical guides 60 to 69.

The guide rollers 32 to 43, 60 to 69 are pivotally mounted around respective perpendicular axes in terms of Figures 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 relative to the chassis 1 of the spreader-lapper. The axes of the rollers 34, 35 and 60, 61, 62, 63 are carried by a first carriage main mobile 10, said entry carriage. The axes rollers 36, 37, 38 and 64 are carried by a second mobile main carriage 14, known as output, and those of rollers 41 and 67 are carried by auxiliary carriages 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 path closed makes a 180 degree turn. Both auxiliary carriages 16, 18 have movements which compensate for those of the main carriages 10, 14 to keep the length substantially constant of each of the closed routes 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 trained in rotation by known means not shown so as to circulate the belts 2, 5 along their respective closed journeys 20 to 31, 50 to 59 according to predetermined kinematic laws. The direction of movement of the belts 2, 5 are indicated respectively by the arrows F2, F5 in 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 pinch area in which the sections of moving carpet numbered 23 and 53 in Figures 2 to 5 are located one against the other so as to pinch the veil 4 between them. The veil 4 is shown in dotted lines in Figure 4 but is not not shown in Figures 2 and 3 to 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 nip are delimited, at the entrance to the nip area, by guide rollers 35, 61 carried by the input carriage 10, and, at the exit from the nip, by rollers guide 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 alternating in a horizontal and perpendicular direction 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 rolls of guide 34, 35 for the front belt 2 and located at inside its closed route 20 to 31. Upstream of the entry carriage 10, the front mat 2 carrying the veil 4 follows the substantially horizontal section 21 in coming from the front side 7. On reaching the input carriage 10, the front belt 2 describes a first turn around the idler roller 34 at an angle A between 0 and 90 degrees oriented downwards 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 horizontal section 23 of the zone pinch, directed towards the front side 7 of the spreader-lapper. Total angular deviation A + B of the front belt 2 around the guide rollers 34, 35 carried by the input carriage 10 is equal to 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 interior to its closed path 50 to 59 and the roller 62, moreover large radius, called detour roller, being external to this closed route 50 to 59. Upstream of the carriage input 10, the rear carpet 5, which does not carry the veil 4, follows the substantially horizontal section 59 coming from the rear side 9. On reaching the input carriage 10, the rear belt 5 describes a first turn around the idler roller 60 at an angle C between 0 and 90 degrees, oriented downwards to enter section 50, then a second 180 degree turn around the roller 61 to enter section 51, then a third turn around the detour roller 62 at a negative angle (because the detour roller 62 is outside the firm path 50 to 59) higher 180 degrees, and finally a fourth turn around of roller 63 to enter the horizontal section 53 of the pinch area, directed to the side before 7 of the spreader-lapper. Angular deviation total of the rear carpet 5 around the rollers guide 60, 61, 62, 63 carried by the input carriage 10 is zero.

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 entry of the pinch area. These two pinch rollers 35, 61 have their respective axes located in the same horizontal plane P. Bypassing the roller 63, located on the input carriage 10 under the horizontal plane P, the rear belt 5 is supported and tangentially joins the front carpet 2 in the pinch zone 23, 53. The veil 4 engages in the pinch area 23, 53 after being transported on sections 20, 21, 22 of the path of the carpet before 2 and be passed between carpet 2, 5 clamps between the rollers 35, 61 along the line of pinching. These pinch rollers 35, 61 can to be pushed elastically towards each other by known return means (not shown).

The input carriage 10 has two sides 11 located on either side of the rollers 34, 35, 60, 61, 62, 63 that he wears. These rollers 34, 35, 60, 61, 62, 63 have their respective axes fixed to their ends on the sides 11. On their opposite face with rollers 34, 35, 60, 61, 62, 63, the sides 11 of the input carriage 10 carry swivel wheels 13 around 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 carriage input 10 in its translational movement. A similar structure, visible in Figure 8, is provided to guide the output carriage 14 in its translational movement.

At the exit of the pinch zone 23, 53, the two belts 2, 5 pass between two rolls of pinch debtors 38, 64 carried by the carriage exit 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 apron 8.

Around the pinch roller 64, the mat rear 5 makes a 180 degree turn to go from horizontal section 53 belonging to the horizontal section pinch area 54 extending immediately above the deck 8. This horizontal section 54 passes under the carriage input 10 to join a guide roller to fixed axis 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 mat 2. At the end of the horizontal section 23 belonging to the area of pinch, the front belt 2 describes a first turn around the deflection roller 36 at an angle between 0 and 30 degrees points upwards to enter section 24, then a second bend around the detour roller 37, located at outside its closed route 20 to 31, following a negative angle greater than 180 degrees to enter in the horizontal section 25, and finally a third 180 degree turn around the pinch roller 38 to enter the horizontal section 26 extending immediately above the deck 8 to join a guide roller with fixed axis 39 located on the front side 7 of the spreader-lapper. The deviation total of the front belt 2 around the rollers guide 36, 37, 38 carried by the carriage exit 14 is zero.

The auxiliary carriages 16, 18 are movable in translation in a horizontal and perpendicular direction 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, away from the areas where the veil 4 and the formed ply 6. The lower passage 70 is separated of the deck 8 by a horizontal partition 72.

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

The auxiliary carriage 18 is provided to maintain constant the length of the closed path 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. Rear carpet 5 is guided between the main carriages 10, 14 and the carriage auxiliary 18 by axis guide rollers fixed 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 which it carries (see FIGS. 6 and 7). Each of these rollers 41, 67 has its axis brought to its ends on the sides 74, 78 of the carriage respective auxiliary 16, 18. On their face opposite the roller 41, 67, flanks 74, 78 carry wheels 75, 79 pivoting around 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. The side rails 76, 80 extend inside the underpass 70 on either side of the rollers 41, 67. As we see it in the partial view of figure 7, they are located at different heights. In the example shown, the bottom rails 76 support the auxiliary carriage 16 guiding the front belt 2 and the upper rails 80 support the auxiliary carriage 18 guiding the rear carpet 5. Above the wheels 79 of the carriage 18 placed on the upper rails 80 extend from the 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 motor pinions 85, 89 rotated by means not shown and intermingling respectively on toothed belts 84, 88 shown symbolically in dashes in Figures 2 to 4.

Two notched belts 84 extend from one side and other rollers and mats between the carriage input 10 and auxiliary carriage 16, passing on the rear side 9 of the spreader-lapper. Between the carriages 10 and 16 to which they are fixed by their ends the notched belts 84 bypass each two return gears 85, 86 (of which the motor pinion 85) pivoting respectively around a fixed axis parallel to the axes of the rollers 32 to 43, 60 to 69. The pinions 85, 86 are arranged so that the end sections of the belts notched 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 both sides of the rollers and belts between the output carriage 14 and the auxiliary carriage 18, 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 notched belts 88 each bypass two idler gears 89, 90 (including motor pinion 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 sections end of the toothed belts 88 are parallel in the direction of translation of the carriages 14, 18 to which they are respectively attached.

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 shown symbolically in dashed lines in Figures 2 to 4. These cables 92, 96 are less extensible than the carpet 2, 5.

Two cables 92 extend on either side rollers and mats between the input cart 10 and its associated auxiliary carriage 16, passing on the front side 7 of the spreader-lapper. Between the carriages 10 and 16 to which they are fixed by their ends, cables 92 each bypass two deflection pulleys 93, 94 pivoting respectively around a fixed axis parallel to the axes of the rollers 32 to 43, 60 to 69. The pulleys 93, 94 are arranged so that the end sections 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 rollers and mats between the exit carriage 14 and its associated auxiliary carriage 18, passing on the rear side 9 of the spreader-lapper. Between the carriages 14 and 18 to which they are fixed by their extremities. cables 96 each bypass deflection pulleys 97, 98 pivoting respectively around a fixed axis parallel to the axes of the rollers 32 to 43, 60 to 69. Pulleys 97, 98 are arranged so that the end sections cables 96 are parallel to the direction of translation of the carriages 14, 18 to which they are respectively fixed.

In operation, we control the drive belts 2, 5 via the rollers motors 39, 65 and that of the carriages 10, 14, 16, 18 via the driving pinions 85, 89 meshing on the toothed belts 84, 88. We thus animates the carriages 10, 14, 16, 18 of movements of synchronous back-and-forth translation. The kinematic laws to be applied to the main carriages 10, 14 can for example be those taught by FR-8- 2 234 395.

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

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

These kinematic relationships between associated carriages are obtained by cables 92, 96 which mate. In the first phase of the movement back and forth going from the position shown to Figure 2 to that illustrated in Figure 3, the gables motors 85, 89 are driven in the direction indicated by the arrows G in figure 2. The belts notched 84 then pull the input carriage 10 towards the rear side 9 and the toothed belts 88 pull the auxiliary carriage 18 towards the front side 7. A traction force towards the front side 7 is transmitted to the auxiliary carriage 16 via the cable 92 which couples it to the entry carriage 10. An effort traction to the rear side 9 is transmitted to the exit 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 in Figure 3 to that illustrated in Figure 2, the drive gears 85, 89 are driven in the direction indicated by the arrows H in figure 3. The toothed belts 84 then pull the auxiliary carriage 16 towards the rear side 9 and the toothed belts 88 pull the exit carriage 14 to the side front 7. Tractive effort towards the front side 7 is transmitted to the input carriage 10 via of the cable 92 which couples it to the auxiliary carriage 16. Traction force towards the rear side 9 is transmitted to the auxiliary carriage 18 via of the cable 96 which couples it to the carriage 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 extensible than the carpets 2, 5.

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

If the angle B was too large (180 degrees or more), we could observe, for cadences high, unwanted peeling of the veil immediately upstream of the pinch roller 35 due to excessive angular deviation or a certain sag of the front carpet 2 in upstream of the pinch roller 35. If the angle B was too weak (90 degrees or less), veil 4 does not would not be transported reliably on the section too inclined 22 preceding the pinch roller 35. The prior pinching of the web 4 between the rollers 35, 61 and the appropriate value for angle B thus ensure the best stability of the transport of veil, which results in a sheet 6 of optimal quality.

In the example of embodiment described, the roller 34 deflecting veil 4 at angle A before the line pinch is mounted on the input carriage 10. It will be understood that the roller 34 could have its axis fixed relative to the chassis 1 of the spreader-lapper. In this case, the angles A and B are variable, but the input cart is lighter and the roller 34 contributes to supporting the mat 2 in upstream of the entry carriage.

After having traversed the pinch zone 23, 53 the web 4 reaches the outlet carriage 14 which deposit by alternating folds on the apron 8 to form tablecloth 6.

The formed sheet 6 is, in a certain measurement, sheltered from the air currents created by the back and forth movements of the carriages 10, 14, 16, 18 due to the presence of the carpet sections 26, 54 located immediately above the deck 8. The presence of the adjacent vertical sections 27, 55 to these sections 26, 54 further contributes to prevent lateral drafts at the level of the tablecloth formed 6. Like the carriages auxiliaries 16, 18 move in the passage lower 70 of the spreader-separator separated from the apron 8 by the partition 72, the air currents caused by their movements basically remain confined inside the underpass 70, at distance from the areas where veil 4 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 great speed.

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

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

We can of course bring various variants in the embodiment described above all remaining within the scope of the present invention.

Claims (7)

1. A crosslapper for folding a web (4) so as to convert it into a fleece (6) and comprising :

   at least two belts (2, 5) each following a closed path (20 to 31, 50 to 59) and associated with rollers (32 to 43, 60 to 69) for their respective guiding and driving, some of the rollers being supported by two main carriages (10, 14) which are movable for translation along an horizontal direction which is perpendicular to the axes of the rollers (32 to 43, 60 to 69), the closed paths (20 to 31, 50 to 59) of the belts being one outside the other and adjacent one another in a pinching zone (23, 53) bounded by some of the guide rollers (35, 61) at an inlet of the pinching zone and by some others of the guide rollers (38, 64) borne by one of the main carriages at the outlet of the pinching zone;

   compensating means comprising two auxiliary carriage (16, 18) movable for translation perpendicular to the axes of the rollers (39 to 43, 60 to 69) in order to keep the length of each closed path (20 to 31, 50 to 59) substantially constant, each closed path (20 to 31, 50 to 59) having a 180° turn around at least one guide roller (41, 67) borne by a respective one of the auxiliary carriages (16, 18);

   means (20, 21, 22) for bringing the web (4) to the inlet of the pinching zone (23, 53);

   an apron (8) movable in a direction parallel to the axes of the rollers (32 to 43, 60 to 69) and receiving the web (4) on leaving the pinching zone (23, 53);

   drive means (84, 85, 88, 89) for applying reciprocating movements of translation to the main carriages (10, 14) and to the compensating means (16, 18); and

   coupling means (92, 96) which are less extensible than the belts (2, 5) and connect each main carriage (10, 14) with an auxiliary carriage (16, 18), the coupling means being arranged to be tensioned under the action of the drive means (84, 85, 88, 89),

      characterized in that the guide rollers (35, 61) bounding the pinching zone (23, 53) at the inlet thereof are supported by the other main carriage (10), and in that both closed paths define the pinching zone by two adjacent horizontal portions (23, 53) extending from said inlet to said outlet of the pinching zone.
2. A crosslapper according to claim 1, characterized in that the coupling means (92, 96) connect a main carriage (10, 14) to an auxiliary carriage (16, 18) which are to be reciprocated at the same speed to maintain the length of one of the closed paths (20 to 31, 50 to 59) at a constant value.
3. A crosslapper according to claim 1 or 2, characterized in that the drive means (84, 85, 88, 89) comprise at least one transmission member (84, 88) which engages a drive pinion (85, 89), one end of the transmission member (84, 88) being secured to a main carriage (10, 14) and the other end being secured to an auxiliary carriage (16, 18), the main carriage (10, 14) and the auxiliary carriage (16, 18) also being connected by said coupling means (92, 96), and when the drive pinion (85, 89) rotates in one direction it pulls the main carriage (10, 14) in a first phase of reciprocating motion whereas when the drive pinion (85, 89) rotates in the other direction it pulls the auxiliary carriage (16, 18) in a second phase of reciprocating motion.
4. A crosslapper according to any of claims 1 to 3, characterized in that the means for coupling an auxiliary carriage (16, 18) to a main carriage (10, 14) comprise at least one cable (92, 96) secured at one end to the auxiliary carriage (10, 16) and at the other end to the main carriage (10, 14), the cable (92, 96) being guided by pulleys (93, 94, 97, 98) between the auxiliary carriage (16, 18) and the main carriage (10, 14).
5. A crosslapper according to claim 4, characterized in that the means for coupling an auxiliary carriage (16, 18) to a main carriage (10, 14) each comprise two side cables (92, 96) secured to said carriages on either side of the rollers (32 to 43, 60 to 69).
6. A crosslapper according to any of claims 1 to 5, characterized in that each auxiliary carriage (16, 18) is situated in a bottom passage (70) extending under the apron (8) and separated therefrom by at least one partition-wall.
7. A crosslapper according to claim 6, characterized in that both auxiliary carriages (16, 18) are slidably mounted on respective side rails or the like (76, 80) extending along the bottom passage (70), the rails (76, 80) being situated at different heigths.

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