EP1036227A1

EP1036227A1 - Method and devices for producing a textile lap

Info

Publication number: EP1036227A1
Application number: EP98954520A
Authority: EP
Inventors: Bernard Jourde; Jean-Christophe Laune; Robert Jean
Original assignee: Asselin SA
Current assignee: Andritz Asselin Thibeau SAS
Priority date: 1997-11-07
Filing date: 1998-11-05
Publication date: 2000-09-20
Anticipated expiration: 2018-11-05
Also published as: WO1999024650A1; KR20010031853A; ES2227887T3; DE69825782T2; CN1285011A; DE69825782D1; CA2310121A1; FR2770855B1; CN1188556C; ATE274081T1; FR2770855A1; EP1036227B1; JP2001522949A; US6195844B1

Abstract

A carding machine or other web production device [(1)] supplies a crosslapper [(2)] with two elementary webs [(15a, 15b)] constituting a lappable web [(16)] which is deposited in a reciprocating manner on a transverse output belt [(26)].In the device [(1) means of] adjustment of the speed of rotation of doffers [(13a, 13b)], of condensers [(17, 18)], of detachers [(19a, 19b)], of the drum [(4)] and/or of the feeder [(7)], and/or [means of] adjustment of the drum-doffer spacing affect the weight per unit area of the elementary web produced taking account of the weight per unit area desired at each point in the width of the fleece [(67)] to be formed on the output belt [(26)]. There is determined the delay length exhibited by each elementary web cross-section undergoing the adjustment of weight with respect to the section of lappable web in the process of being deposited. From this there is derived the position at which each web cross-section will be deposited when it is undergoing the adjustment of thickness and consequently the weight adjustment to be applied to it.[Utilization] The present invention is useful for producing fleeces of highly varied profiles with great industrial flexibility.

Description

DESCRIPTION "Method and devices for producing a textile web" The present invention relates to a method for producing a textile web using a spreader-lapper.

The present invention also relates to various devices allowing the implementation of this method.

It is known to produce a covering veil in a carding machine or in another device such as for example a pneumatic lapper. The covering veil thus obtained feeds a spreader-lapper in which the veil is folded alternately in one direction and in the other on an output belt. The tablecloth is thus made up of overlapping segments of sail, tilted alternately in one direction and the other. The folds between successive segments are aligned along the lateral edges of the sheet produced.

The sheet of fibers obtained is generally intended for a subsequent consolidation treatment, for example by needling, by coating, and / or etc. The FR-A-2 234 395 teaches the speed relationships which must be observed in 1 ' spreader-lapper to control the thickness of the tablecloth at all points of its width.

According to EP-A-0 315 930, the ply may have, in cross section, a profile of non-uniform thickness. For this, the speed of the lapping carriage is varied, which deposits the covering veil at a point that is variable in the width of the exit belt, relative to the speed of the belts which unwind the veil on the exit belt through this carriage. If in a given position of the width of the web, the carriage moves at a speed greater than that at which it unwinds the web, the web is stretched and this reduces the thickness of the web at this location. If, on the contrary, the speed of the carriage is lower than the speed of unwinding, the web is deposited in a compressed form which increases the thickness of the sheet at this location. This method of profiling the sheet has certain limitations. With certain types of fibers or certain types of veils, in particular those in which the fibers are strictly longitudinal, the tensile or compressive stresses imposed on the veil tend to be absorbed by elasticity after the deposition of the covering veil on the exit mat , and / or to be transmitted to the neighboring regions of the veil. In addition, the traction or compression imposed on the veil cannot without risks exceed certain limits, which vary according to the nature of the veil and the fibers.

EP-B-0 371 948 describes a process intended to pre-compensate the defects occurring during the subsequent consolidation, in particular the needling, by locally varying the thickness of the covering veil introduced into the spreader-lapper. This is achieved by automatically adjusting the speed of a card comber relative to the speed of the card drum. The faster the drier turns relative to the drum, the more the veil formed by the drier has a reduced surface weight. The object of the present invention is to improve this known process with regard to at least one of the following aspects:

- inertias used to vary the surface weight of the web entering the spreader; - precision in determining the section of an elementary web where a specific surface weight must be achieved so that this section takes a determined position in the width of the sheet produced by the spreader; compatibility between the variable speeds of the doffer and the speeds, also variable, of the carriage-lapper of the spreader-lapper;

- extension of possible applications of the process;

- definition of new structures for the covering veil. According to the first aspect of the invention, the method for producing a textile sheet in which one produces at at least one elementary veil, then by means of a spreader-lapper a covering veil incorporating said elementary veil is folded, alternately in one direction and in the other on a transverse exit mat of the spreader-lapper, is characterized in that by modifying substantially according to a periodic law at least one adjustment upstream of the spreader-topper, the covering web introduced into the spreading-table is given a surface weight which varies according to the longitudinal direction of the covering web so that the sheet obtained at the outlet of the spreader-lapper has over its width a surface weight distribution which is substantially predetermined.

It may be advantageous for the adjustment which is modified upstream of the spreader-topper to include an adjustment affecting the card in a zone located downstream of a drum of the card, relative to the direction of transit of the fibers in the card, and independently of the speed of rotation of a doffer taking from the carding drum the fibers intended to constitute the elementary web. - The rotational movement of the comber involves strong inertias, which limits the speed of reaction when the speed setting is changed.

By carrying out the adjustment other than by variation of the speed of rotation of the doffer, one can carry out faster variations therefore better localized. It is in particular possible to vary the spacing between the periphery of the drum and the periphery of the painter. The greater this spacing, the thinner the layer of fibers removed by the painter from the drum. There is also the advantage that this mode of adjustment does not modify the speed of production of the web and therefore poses no particular problem when entering the spreader-lapper.

It is also envisaged, according to the invention, to vary the speed of members placed upstream of the doffer. We can for example vary the speed of the organs called "food" of the card which supply, at least indirectly, the card drum with fibers upstream of said drum. You can also vary the speed of the card drum relative to the doffer. All of these solutions also have the advantage of not affecting the speed of production of the web, which can therefore remain at any time equal to a constant speed of entry into the spreader-lapper. To reduce the inertia of the drum, it can be made of carbon.

When the doffer is followed by at least ^a condenser roller, the speed can be varied at least one roller relative to doffer condenser so as to condense more or less the elementary web drawn from the drum by the doffer.

The last element at the exit of the card is generally constituted by a member called detacher which detaches the veil from the last condensing roller, or from the doffer in the absence of condensing roller. It is also proposed according to the invention to adjust the surface weight of the sail by varying the action of the detacher. In particular, when this detacher is a rotary roller provided with a peripheral lining, the speed of rotation of the detacher can be varied relative to the rotary member, for example comb or condenser, located immediately upstream.

According to an important aspect of the invention, when the adjustment made has the effect of varying the speed at which the haze produced is supplied to the spreader-lapper, which is particularly the case when operating by varying the speed of a comber, of a condenser roll or of a detacher, the speed of entry into the spreader-topper is varied so that it corresponds substantially, at all times, to the speed at which the veil arrives at the spreader, and the length of a web accumulation path in the spreader is adjusted at all times to compensate for the differences between the instantaneous speed of entry into the spreader and the instantaneous speed at which 1 spreader-lapper unwinds the covering veil on the output belt.

Known spreaders-lappers define a haze accumulation path. FR-A-2 234 395 teaches to vary the length of this path so that the speed at which the lapping carriage unwinds the veil on the output belt varies and in particular is canceled when the speed of the lapping carriage is itself null at its points of inversion of movement. According to the present aspect of the invention, the length of veil accumulated in the spreader is also varied, but to compensate for the fluctuations in the speed at which the lapping veil enters the spreader due to the adjustment. of surface weight operated upstream. It is also within the scope of this aspect of the invention to vary the length of sail accumulated in the spreader to take account of both variations in speed of entry of the sail into spreader and variations in speed to which the lapper carriage unwinds the veil on the output belt. - One can for example directly control the speed of an incoming section of a conveyor belt of the spreader-lapper to make this speed -.concordant with that at which the carding machine or other production device provides the veil. The speed of an accumulator trolley of the spreader-lapper is then controlled over which this conveyor belt passes, so that this same mat takes up in the lapper trolley, over which it also passes, and taking account of the speed of movement. of the lapping carriage, a speed of unwinding of the web corresponding to the desired speed. Conversely, it is also possible to directly control the speed of a section of the conveyor belt adjacent to the lapping carriage so that the unwinding speed of the lapping carriage corresponds to the desired speed. The speed of the accumulator carriage is then controlled so that the incoming section of the conveyor belt has a speed which matches that at which the card produces the web. We will call "section of veil" a cross section of the veil at a determined point of the length of the veil.

The length of the sail, between a first section of the sail, being deposited on the web being formed in the spreader-lapper, and on the other hand, will be called "delay length". a second veil section located at the point of the path of the fibers where said adjustment influences the surface weight of the elementary veil upstream of the spreader-lapper.

According to another important aspect of the invention, the delay length is determined, and according to this the point of the width of the sheet where the second section will be deposited is determined. The surface weight of the second section is then adjusted according to the surface weight programmed for said point of the width of the sheet. If the spreader-lapper, by construction or by programming, unwinds the covering veil on the output conveyor at a speed which is always equal to the speed of movement of the lapping carriage, and if there is no drawing of the veil upstream of the lapping carriage, the lapping veil to be produced is the same as that which would be obtained by unfolding the tablecloth-obtained to re-obtain the vehicle.

If a stretch with a constant factor greater than 1 (true stretch) or less than 1 (compression) occurs in the path of the web between the two sections, it is a corrected delay length that must be taken into account for the part located upstream of the stretching area. If for example a stretching factor equal to 1.1 occurs at a point in the path, the part of the delay length located upstream of this point must be multiplied by 1.1 (increased by 10%) to know the length corrected delay to be taken into account. The veil to be produced is then different from that which would be obtained by unfolding the sheet obtained. There can also be a variable stretch in the path of the web until it is deposited on the output mat, and in particular between the topping carriage and the output mat. In known manner, this typically results from a variable difference between the speed of movement of the coating carriage and the speed at which the coating carriage unwinds the covering veil on the output belt. It is then possible to provide in the central unit an integral calculation software making it possible to obtain the corrected delay length by summing the elementary displacements of the lapping carriage necessary to deposit the elementary lengths of the actual delay length on the output belt, in as a function of the stretching value provided at each point of the reciprocating stroke of the lapping carriage. This calculation can still be done outside the machine and a table of corrected delay lengths for each position of the lapping carriage can be entered into a memory of the machine. In operation, a central unit of the production device can then very quickly, for each position of the lapping carriage, with reference to the table, know the position which the sail section which will be at the moment taking will take in the width of the lap. to undergo the area weight adjustment. It can also be provided that after a programming step before the start of the production of the tablecloth, the central unit calculates the above table, and stores it in memory so that, during production, it can then be referred to for each position. of the lapper carriage. Yet another method will be explained in the body of the description.

The method according to the invention can be implemented by means of a programmable control allowing the user to enter into a memory the distribution of the surface weights desired for the covering veil arriving in a lapping carriage of the spreader-lapper at each point of a course of the lapper carriage. The programming can relate to a simple race consisting of a round trip between the two points of race reversal, or a round trip return to allow the user to adjust the surface weight of the web differently on the outward and return journey of the lapping carriage at at least one determined point of the width of the lap. In a simple version where the surface weight is only adjusted for a single stroke and where no stretching is provided at the exit of the lapping carriage (therefore no difference between the speed of movement of the lapping carriage and the speed at which the lapping carriage unwinds the veil on the exit mat), it is equivalent to programming the surface weight desired for the veil at each point of the simple stroke of the lapping carriage and to programming the surface weight desired for the tablecloth at each point of its width.

In more sophisticated versions, it is however possible to combine, as has been said above, a variation of the surface weight of the web arriving in the lapping carriage and a variation of the drawing produced by difference between the speed of movement of the lapping carriage and the speed of unwinding of the web through the lapping carriage. In this case, it is advantageous that the two parameters can be programmed separately for each point of the stroke (simple or back and forth) of the lapping carriage. The data of this program will be used by the programmable control to determine, as said above, the point of the width of the sheet where a section is to be deposited undergoing the adjustment of the surface weight, and consequently the weight area to be obtained at this time by means of said adjustment.

In some spreaders of simple construction, the variable draws at the outlet of the lapping carriage are an inevitable drawback consisting of compressions at the ends of the stroke of the lapping carriage. Adjusting the surface weight of the covering veil according to the invention makes it possible to compensate for this defect. For this, the sections of covering web intended to form the edges of the sheet have a reduced surface weight. It is possible to produce the covering veil by superimposing at least two elementary veils. Many cards indeed have at least two combers each producing an elemental veil, so as to increase the possible production from a single card drum. It is then possible to structure the covering veil by giving the two elementary veils different textures. For example, one of the food webs can be condensed to give the fibers a sinuous orientation on either side of the longitudinal direction, the other being less condensed or not condensed at all so that a certain dose of longitudinal fibers gives the covering veil a dimensional stability in the longitudinal direction, in particular with regard to the tensile forces. It may then be advantageous to reinforce the structuring effect by adjusting the respective surface weights of the two elementary webs in a different manner in order to achieve the desired covering web.

On the one hand, the delay lengths can be different for the two elementary webs. A corresponding phase shift must therefore be provided between the two adjustments made at each instant.

On the other hand, it may be desirable for the elementary sail sections which are superposed to have surface weights which are similarly affected by the adjustment, or on the contrary differently affected. One can for example provide that only one of the two elementary webs undergoes a variation in surface weight.

If the variations in surface weight are obtained in a manner which induces a variation in the speed of production of the sail, it is preferable that the lengths of delay are substantially the same for all the elementary sails and that the speed variations undergone by the sails elementary are substantially the same, so that the elementary sails have substantially the same speeds at the station of superposition of the elementary sails. Depending on the geometry of the card, it is possible in some cases to equalize the delay lengths by using different adjustment means, for example by adjusting the surface weight of an elementary veil by means of the doffer and the surface weight of the another elementary veil by means of the condenser.

One can foresee that one of the elementary veils undergoes the relatively slow surface weight variations, operated by means of a variation of the speed of rotation of the drum relative to the speed of rotation of the doffer, and that the other elementary veil undergoes the more abrupt variations, intended for example to produce a change in thickness between two zones of the final consolidated product, for example by means of a variation in the spacing between the doffer and the carding drum.

It should however be noted that such a differentiated treatment of slow variations and sudden variations in the surface weight is also possible on a single elementary veil, in particular but not limited to when the covering veil is obtained from an elementary veil unique. One can then, for example, operate the slow variations by variation of the speed of the doffer or the drum and the sudden variations by another means, for example by varying the speed of rotation of one or more condensing rollers relative to the comb or a detaching roller relative to the rotary member, comb or condenser, located immediately upstream.

It is still within the scope of the invention to produce a covering veil by means of two elementary veils, each of which has its surface weight adjusted only by variation of the speed of rotation of the doffer relative to the drum, or even only one elementary sails has its surface weight adjusted by variation of the speed of rotation of the doffer relative to the drum. The fact that the speed of rotation of the comber is used as a variable for adjusting the surface weight of the associated elementary veil does not mean that the other rotational speeds remain constant along the path of this elementary veil: when the speed of a rotary member located downstream of the drum is modified to vary the surface weight of the veil produced, the speeds drive of all drive elements located even further downstream must be modified substantially in proportion if one wishes to transmit without modifications the longitudinal profile of the surface weights generated by the adjustment. When adjusting the speed of transfer of fibers from an organ located upstream of the comber, it may be appropriate to modify the speed of transfer of fibers from organs located even further upstream.

According to another aspect of the invention, the device for implementing a method according to the first aspect, comprising a card incorporating at least one means of adjustment in operation, under the action at least indirect of a programmable control , of the thickness of at least one elementary veil produced in a veil production path, is characterized in that this adjusting means is chosen from:

a means of adjusting a spacing between a doffer and "a card drum,

a means for adjusting the speed of rotation of a condenser relative to the speed of rotation of the card doffer,

a means for adjusting the speed of rotation of a detacher relative to the speed of rotation of a fiber transfer member, such as a comber or a condenser, located immediately upstream;

- A means of adjusting the speed of a fiber transfer member located upstream of the comber.

According to another version of the device for implementing the method according to the first aspect, it comprises a sail production apparatus having at least two paths for producing a respective elementary sail, the two paths then joining at a station for superposing the two sails, and is characterized in that it further comprises at least one means for adjusting, in operation, under the action of a programmable control, the thickness of at least one of the elementary veils, so that the covering veil obtained by superposition of the elementary veils has a thickness which varies according to its longitudinal direction.

According to another aspect of the invention, the device for implementing the method, comprising: an apparatus for producing at least one elementary veil, and including means for adjusting the surface weight of at least one elementary veil produced , a spreader-lapper receiving a lapping veil incorporating said at least one elementary veil and leading the lapping veil according to a path of variable geometry to a lapping carriage movable back and forth transversely above an output conveyor , and

a programmable control capable of sending at least indirectly to said adjusting means a control signal for the surface weight to be given to the elementary web at each instant as a function of the position of the lapping carriage, is characterized in that the programmable control comprises means for taking into account the length of the sail between a first section of sail being deposited on the exit mat of the spreader-lapper and a second section of sail undergoing the adjustment, and a total distance to be covered by the lapper carriage to deposit this length, to determine the point of the width of the lap where the second section of veil will be deposited, and to form said control signal as a function of the surface weight desired for the lap veil at the point of the width of the tablecloth where this second section of the veil will be deposited. According to yet another aspect of the invention, the device for implementing the method, comprising: - a spreader-lapper including a movable lapper carriage back and forth transverse above an output belt, and an accumulation means for adjusting the length of a lapping veil accumulated in the spreader-lapper; and - an apparatus for producing at least one elementary veil for composing the covering veil sent to the entry station in one spreader-lapper, is characterized in that the production apparatus includes for adjusting the surface weight of the veil elementary an adjustment means producing a fluctuation in the speed of the covering veil around the average speed at which the lapping carriage unwinds the covering veil, and in that the accumulation means is controlled to vary the length of the accumulated veil in the spreader as a function of the difference between the speed of entry of the covering veil into the spreader and the speed at which the lapping carriage unwinds the veil on the exit belt.

Other features and advantages of the invention will emerge from the description below, relating to non-limiting examples. In the accompanying drawings:

- Figure 1 is a "--schematic side elevation view of a device according to the invention; Figure 2 is a top view of the sheet produced on the output belt;

- Figure 3 is a view similar to a part of Figure 1 but relating to another embodiment;

- Figure 4 is an explanatory view of the spreader-lapper of Figure 1; and - Figures 5 and 6 are two explanatory views of certain aspects of the method and the devices according to

1 inventio.

It is specified here that the figures are purely illustrative and do not pretend to show either the details of construction or the actual proportions of a card and a spreader-lapper. In the example shown in FIG. 1, the device comprises a card 1 and a spreader-lapper 2.

The card 1 comprises a frame 3 supporting in rotation a card drum 4 driven in rotation by a motor 6. The frame 3 also supports at least one "food" 7 essentially comprising a conveyor belt driven in rotation by a motor 8. The food 7 carries textile fibers 9 from a reserve and arranges them, in general by means of at least one cylinder 10, on the periphery of the drum 4. Thus, food 7 regularly renews a layer of fibers 11 at the periphery of the drum 4. There are around the periphery of the drum 4 cylinders of known type, such as 12, (of which only one pair is shown for clarity) which are used for working the fibers and in particular for orient them circumferentially around the periphery of the drum 4.

The fibers coming from food 7 reach the drum 4 in the beginning of the rising zone of the periphery of the drum 4. There is in the descending zone of the periphery of the drum 4 at least one comber 13a, 13b constituted by a cylinder rotating around its axis parallel to that of the drum 4 by means of a specific motor 14a, 14b. There is between each comb 13a, 13b and the periphery of the drum 4 a spacing chosen so that each comb 13a, 13b, thanks to an appropriate lining of its cylindrical periphery, takes a part of the fibers 11 driven in rotation by the drum 4 for forming with these fibers an elementary veil 15a, 15b. In the example shown, the elementary web 15a, after having completed a fraction of a turn at the periphery of the doffer 13a, is taken up by a detaching cylinder 19a to be deposited on an intermediate conveyor 21 driven by a specific motor 22.

The elementary veil 15b, after having carried out a fraction of a turn on the periphery of the doffer 13b, is resumed by a succession of two condensing cylinders 17, 18 then, from there, by a detaching cylinder 19b.

The condenser cylinders 17, 18 and the two detaching cylinders 19a, 19b have axes parallel to the combers 13a, 13b and have much smaller outside diameters than the cylinders of the combers. In general, the detaching cylinders 19a, 19b are themselves of smaller diameter than the condensing cylinders 17, 18. The first condensing cylinder 17 is substantially tangent to the periphery of the combing cylinder 13b, with however a gap between them. The same applies to the second condensing cylinder 18 relative to the first condensing cylinder 17, and to the detaching cylinder 19a relative to the combing cylinder 13a and to the detaching cylinder 19b relative to the second condensing cylinder 18.

The condenser cylinder 17 has a peripheral speed lower than that of the doffer 13b located just upstream so as to cause an increase in the surface weight of the web, accompanied by a sinuous orientation of the fibers in the web. In general, the condenser cylinder 18 rotates at a lower speed than that of the condenser cylinder 17.

Figure 1 illustrates by arrows that, conventionally, wherever cylinders are substantially tangent by their periphery, the speeds at the periphery are oriented in the same direction, except for the detachers 19a, 19b which therefore cause a reversing the direction of movement of the fibers in the vicinity of the point of tangency with the rotary element 13a and respectively 18 above. The detacher 19b deposits the second elementary web 15b directly on a front conveyor belt 24 of the lapper spreader 2 and more particularly on a section 23 by which this carpet enters the lapper spreader 2. The intermediate conveyor 21 deposits the first elementary veil 15a on the section 23 above the elementary web 15b deposited in upstream so as to compose a covering veil 16 with the superposition of the elementary veils 15a and 15b.

The function of the spreader 2 is to deposit the veil 16 in a zigzag pattern on an output belt 26 moving perpendicular to the direction of entry of the covering veil 16 in the spreader. The direction of movement of the outlet conveyor 26 is therefore approximately perpendicular to the plane of FIG. 1. To thus deposit the web, the spreader-lapper comprises a lapper carriage 27 which moves back and forth over the conveyor outlet 26 parallel to the width thereof. The lapping carriage 27 has a slot 28 above the outlet belt 26 through which the lapping veil 16 is unwound at a point variable in the width of the outlet belt 26. The lapper spreader further comprises an accumulator carriage 29 movable back and forth above the lapping carriage 27 and parallel to it.

After the entry section 23 defined by fixed rotary rollers 31, 32, the front belt 24 makes a 180 ° turn on two rollers 33 carried by the accumulator carriage 29 then defines one of the sides of the unwinding slot 28 in bypassing a roller 34 carried by the lapper carriage 27.- Next, the front belt 24 follows a return path on various fixed rollers 36, passing through a 180 ° loop on a roller 37 carried by a compensating carriage 38 which moves at all times at equal speed and in the opposite direction to the accumulator carriage 29. The length of the path followed by the conveyor belt 24 is always the same because any variation in the length of the loop formed by the conveyor belt 24 on the accumulator carriage 29 is compensated by an opposite variation in the length of the loop formed by the belt 24 on the compensating carriage 38.

The covering veil 16 moves substantially along the outside face of the front belt 24 from the entry section 23 to the unwinding slot 28. The covering veil 16 therefore forms a length accumulation loop variable around the rollers 33 of the accumulator carriage 29 as a function of the position of this carriage along its back-and-forth travel. In certain known spreader-lappers, the accumulator carriage 29 is moved so as to vary the length of the accumulation loop to accumulate haze when the constant input speed is greater than the instantaneous speed at which the lapper carriage unwinds the veil on the exit mat, and to restore part of this loop to the lapper carriage otherwise. Less sophisticated spreader-lappers are also known where the lapper carriage unwinds the veil with a constant speed equal to the constant input speed: the accumulator trolley then only serves to keep a constant length of veil in the spreader-lapper whatever the position of the lapper carriage along its back-and-forth travel.

In the part of its path between the accumulator carriage 29 and the lapping carriage 27, the covering veil 16 is supported, on the side opposite to the front mat 24, by a rear mat 41. This passes over rollers 42 carried by the accumulator carriage 29 and bypasses on the lapping carriage 27 a roller 43 on which the rear belt defines the other side of the unwinding slot 28, facing the roller 34. The rest of the path of the rear belt 41 is defined by fixed position rotary rollers 44, 46, also passing through a 180 ° loop on a roller 47 carried by a compensating carriage 48 which moves at all times at equal speed and in opposite directions to the lapping carriage 27. Thus, the path followed by the rear belt 41 has a constant length because any variation in the length of the 180 ° loop formed by the rear belt 41 around the roller 43 of the lapping carriage 27 is offset by an opposite variation in the length of the loop e at 180 ° formed by the same mat on the compensating carriage 48. The accumulating carriage 29 is connected to the compensating carriage 38 associated by means of an inextensible cable 49 making a global turn of 180 ° between one of its ends coupled to the accumulator carriage 29 and its other end coupled to the associated compensating carriage 38. This 180 ° turn is carried out at least in part on a driving pulley 51 coupled to a motor drive 52 in both directions of travel which is of the servomotor type stepping motor ^"step, or the like. in each direction of rotation, the cable 49 takes the storage carriage 29 or the compensating carriage respectively 38 extending in the direction the loop formed on it by the front belt 24. Given the invariable length of the front belt 24, the other loop must necessarily shorten and bring the other carriage in the desired direction. avoid the resulting traction on the front belt 24 and the corresponding wear of the carpet, a second cable can connect the accumulator carriage 29 and its compensating carriage 38 passing on the other side of the output belt, com describes me in EP-B-522 893.

The control of the lapping carriage 27 and of the associated compensating carriage 48 is carried out substantially in the manner described for the accumulator carriage 29 and the associated compensating carriage 38. A cable -53 connects the two carriages 27, - 48 by making a 180 ° turn at least in part on a pulley 54 mounted in a fixed position and connected to a servomotor, stepper motor or the like in two directions of travel. 56. In each of its directions of movement, the motor 56 pulls the carriage 27 or 48 in the direction extending the loop made on this carriage by the rear belt 41. The other carriage then moves in the opposite direction thanks to the invariability of the length of the rear belt 41 or by means of an additional cable passing through the other side of the output belt 26.

Furthermore, the speed of movement of the front belt 24 is defined by a servo motor, stepping motor or the like 57 associated with one 31 of the fixed cylinders supporting the front belt 24 in the inlet section 23. The speed movement of the rear belt 41 is defined by a servo motor, stepper motor or the like 58 associated with the fixed cylinder 44 supporting the rear belt 41 along its return section comprised between the compensating carriage 48 and the accumulator carriage 29. In operation, the covering veil 16 is conveyed by the inlet section 23 of the front belt 24, then crosses the accumulator carriage 29 then the lapping carriage 27, and comes to form on the output belt 26 segments which overlap with an obliquity alternately in one direction and in the other. The rear edges of these segments, relative to the direction of movement of the output belt 26, are visible at 59 in FIG. 2.

The spreader-lapper also comprises a control unit 61 which manages at each instant the respective angular positions to be achieved by the motors 52 and 56 for controlling the position of the accumulator 29 and lapper 27 carriages along their forward travel and comes, and by the two motors 57 and 58 defining the circulation of the front belt 24 and the rear belt 41. In a manner not shown, the control unit 61 can also control a motor for driving the output belt 26 according to a known method, for example at a constant speed or on the contrary at a speed proportional to that of the lapping carriage 27 as taught by FR-A-2 234 395. The device further comprises a control unit 62 associated with the card and controlling in a coordinated manner the speed of rotation of the motors 6, 8, 14a, 14b and 22 already described and shown as well as various other motors, not shown for reasons of clarity, causing in particular the detaching cylinder 19a, the condensing cylinders 17 and 18 and the detaching cylinder 19b respectively. All these motors of the card are capable, if necessary by means of a regulation loop passing through the control unit 62, of executing an instruction of speed of rotation and even preferably an instruction of angular position determined at each instant, whence it also results a speed of rotation determined at each instant.

One of the control units, preferably the control unit 61 associated with the spreader-lapper 2, is programmable in a manner allowing the operator to define, for each position of the lapper carriage 27 along its back and forth stroke, the desired surface weight for the covering veil 16 in the section undergoing deposition by the lapping carriage 27 on the output belt. Thus, each time the lapping carriage passes at a determined point in its back-and-forth travel, the lapping veil 16 will have a determined surface weight and therefore the web produced, constituted at all points by a constant number of veil segments superimposed, will itself, at each point of its width, a surface weight respectively determined. This programming is feasible before the start of production, with improved designs allowing modification of the programming during operation.

The variations in surface weight of the successive sail sections which are unwound by the lapping carriage 27 on the output belt 26 result from an adjustment controlled continuously by the central unit 62 of the card 1. In the example shown in Figure 1, this setting can affect the speed of rotation of the motor 8 of the food 7 relative to the speed of rotation of the motor 6 driving the drum 4. If the motor 8 rotates faster, the food 7 provides more fiber at the periphery of the drum 4. Consequently, after a determined peripheral path corresponding to a fraction of a turn of the cylinder 10 and a fraction of a turn of the drum 4, more fibers 11 reach the combers 13a and 13b. This results in the production of elementary webs 15a and 15b having a higher surface weight. Conversely, a slower rotation of the motor 8 of the food 7 produces elementary webs having a lower surface weight. The area weight adjustment can also consist, at least in part, of a variation in the speed of the card drum 4. The faster the card drum rotates relative to the combers 13a and 13b, the more the elementary webs 15a and 15b collected by these are heavy, per unit of area. A variation in the speed of rotation of the drum 4 can if necessary be accompanied by a corresponding variation in the speed of rotation of the motors driving the fiber transfer members located upstream, namely the food 7 and the cylinder 10 in the example shown.

The adjustment can also affect one and / or the other of the combers 13a and 13b. If their motor drives them at a higher speed compared to the carding drum 4, they produce elementary webs 15a and 15b at a faster speed having a lower surface weight. On the contrary, if one slows down the rotation speed of at least one of the combers 13a or 13b, this produces at lower speed a web having a greater surface weight. Any variation in the speed of rotation of a doffer in order to modify the surface weight of the elementary veil must be accompanied by a corresponding variation, that is to say in principle in the same proportion, in the speed of the organs of veil transfer located downstream, therefore the detacher 19a and the intermediate belt 21 as regards the doffer 13a, and the condensers 17 and 18 and the detacher 19b as regards the doffer 13b, in the example shown. It is also appropriate to modify the speed of the input section 23 of the front belt 24 by appropriate control of the motor 57 for driving this belt, as will be explained in more detail below.

It is generally done so that the speeds of the two elementary webs 15a and 15b on arrival on the entry section 23 of the front belt 24 are little different from each other and from the speed of circulation of this section, knowing that in practice speed differences of the order of 10 to 15% are tolerable.

The adjustment of the surface weight of at least one elementary veil 15a or 15b can also consist of an adjustment of the speed of rotation of the condensers 17 and 18 relative to the speed of the doffer 13b located upstream, so as to more or less condense the elementary veil produced by the painter 13b. The condensation is all the stronger, and consequently the areal weight all the higher, that the speed of the condensers is reduced compared to that of the doffer 13b. The speed of the first condenser 17 can be modified relative to the speed of the doffer 13b and the speed of the second condenser 18 can be varied proportionally. The speed of rotation of the condenser 18 relative to that of the condenser 17 can be varied than that of - either in a constant or variable relationship with that of the painter 13b. In all cases, the transfer speeds defined by the detacher 19b and the inlet section 23 of the spreader-lapper vary in proportion to that of the condenser 18, if it is desired that these elements located downstream of the condenser 18 transmit the surface area variations of the elementary web 15b without modification.

It is also possible to modify the surface weight of a web 15a and / or 15b by varying the speed of rotation of the respective detacher 19a and / or 19b relative to the speed of rotation of the fiber transfer member located immediately. upstream, that is to say the doffer 13a as regards the detacher 19a, and the condenser 18 as regards the detacher 19b. If the speed of rotation of the detacher 19a is varied relative to that of the doffer 13a, the speed of the intermediate belt 21 is correspondingly varied. Furthermore, here again, the speed of the inlet section 23 is adapted. of the carpet 24 to the variations that the adjustment of surface weight induces on the production speed of the webs 15a and 15b. FIG. 3 shows another embodiment of the card 1, according to which at least one comber 13, as well as the associated condenser 17, 18 and the detacher 19 are all supported on a carriage 63 which is movable relative to the frame 3 of the card 1 in a direction of translation varying the spacing E between the card drum 4 and the doffer 13. The movement of the carriage 63 is controlled by a positioning motor 64 receiving control signals from the control unit 62. The motor 64 actuates the carriage 63 for example by means of a screw mechanism 66. When by an appropriate control of the motor 64 the control unit 62 causes an increase in the interval E, this results a reduction in the surface weight of the web taken up by the doffer 13 without it being necessary to vary the speed of rotation of the doffer 13, of the condensers 17, 18 and of the detacher 19, therefore without variation of the speed at which the corresponding elementary veil is produced. It is therefore not necessary to adjust the speed of entry into one spreader-lapper when the -adjustment of the surface weight of the elementary web is produced only by a variation of the spacing E. An adjustment of the surface weight obtained by variation in the speed of rotation of the drum 4 or of any other fiber transfer member, such as food 7, located upstream of the comber (s) such as 13, has the same advantage.

In practice, the adjustment of the surface weight by variation of the spacing of the comber (s) relative to the carding drum is very advantageous since it does not impose any variation in speeds, either upstream or downstream. In a card with at least two combers, elementary webs having different surface weights and varying in a different manner or offset in time with respect to each other can be produced and delivered to the stacking station at a constant speed which is the same for the at least two elementary sails, this speed also being that of the inlet section 23, in principle. We can obtain a similar result by combining a variation of the speed of the drum 4 or of an organ situated upstream and a variation of the spacing E of one of the combers relative to the drum 4 to modify the weight of one of the sails elementary compared to the variable weight of the other sail.

We will now explain, with reference to FIG. 4, how, according to the invention, the speed of the incoming section 23 of the front belt 24 can be varied without disturbing the rest of the operation of the spreader-lapper, and in particular without inducing for modifying the speed at which the lapper carriage unwinds the web on the output belt 26.

In this figure, all the speeds are shown with arrows corresponding to the positive counted direction, which is the direction to the right (direction of routing by the incoming section 23) for the horizontal speeds and the downward direction for the vertical speeds.

The belts 24 and 41 have in the area between the carriages 27 and 29 a speed V ₂ , given by the following relationship:

V ₂ = V ₃ - Given the stretching factor k (if k = 1, there is neither -stretching nor compression) due to a difference between | V ₃ I and | I, we have the relation: V ₃ = | | / k

The result is:

V2 = | i / k - W (RI)

It can also be seen that, if Vi is the speed of movement of the section 23 and U is the speed of movement of the accumulator carriage 29: V ₂ = -Vi + 2U from which it results:

U = (VI + V2) / 2 and therefore, taking into account the relation (RI): U = (V _x + | w | / k - W) 12 (R2) The application of these calculations translates into practice as follows:

Depending on the speed at which the elementary veil is produced, the central unit 61 sends an instruction to the motor 57 to adjust the speed of the motor 31 in correspondence so as to give the input speed Vi of the belt before 24 the value adapted. Furthermore, the lapping carriage 27 can for example follow a predetermined periodic speed law, according to which the value of the speed of movement W of the lapping carriage 27 is determined for each point of the reciprocating stroke.

Consequently, the motor 52 driving the lapping carriage 27 is controlled so as to generate the desired speed law for the speed of movement W of the lapping carriage 27 as a function of its position along its reciprocating stroke. Vi and W being fixed at each instant as has just been said, the relation (R2) gives the value "U", the stretching factor "k" being also programmed or in any case known from the construction of the spreader for each point of the stroke of the lapping carriage 27. We therefore control, from the central unit 61, the motor 52 for driving the accumulator carriage 29 to give it the speed U determined as we have just expose according to relation (R2). The motor 58 for driving the rear belt 41 is controlled so that the speed V ₄ of circulation of the rear belt 41 in the area adjacent to the entry into the accumulator carriage 29 is such that V ₄ = V ₂ = 2U - Vi . It will easily be verified that in this way each zone of the rear belt 41 has the same speed as each zone of the front belt 24 which faces it in the path comprised between the accumulator carriage 29 and the lapping carriage 27.

The mathematical laws which have been given above are only an example to show the feasibility of the method according to the invention. In detail, these laws may vary depending on the kinematics of the spreader-lapper used. It exists many types of spreader-lappers marketed or known in the literature.

It will be understood that the calculations set out above will give the same results each time the lapping carriage passes through a given position, whatever it may be. It is therefore not necessary for the control unit 61 to redo the calculations each time. It will suffice that it makes them once at the start of a given production, then that it stores them in memory in the form of a table giving all the speeds or angular positions to be achieved for each position of the lapper carriage 27.

The process which has just been described is applicable even if the law giving the speed "W" of the lapping carriage 27 as a function of its position along its back-and-forth travel is not a constant law fixed once and for all in the control unit 61, but on the contrary a law that the control unit 61 is able to modify for example to optimize the distribution of speeds and accelerations as a function of various parameters such as width of the ply to be produced, average speed work of the spreader-lapper, spatial law of distribution of any stretching, etc.

In the implementation of the method according to the invention, it is furthermore made so that: i means = V ₃ means on each outward and return stroke of the lapping carriage. Thus, the amount of haze accumulated in the spreader fluctuates only between two limit values, and it is therefore possible to ensure that the accumulator carriage 29 only moves between two limit positions compatible with the material construction of the machine. .

Instead of driving the sections of the belts 24 and 41 moving towards the accumulator carriage 29, the motors 57 and 58 can also each drive any other guide roller of the belt which is respectively associated with it. They can in particular, as shown in dotted lines in FIG. 4, be positioned respectively at 57a and 58a to drive one of the fixed rollers 36 and respectively 46 guiding the front belt 24 and respectively the rear belt 41 at the outlet of the lapper carriage 27. In this case, the operating conditions already described are achieved if the motor 57a gives the front belt 24 a speed V ₅ such that:

V ₅ = W - V ₃ = W - | | / k and if the motor 58a gives the rear carpet 41 a speed Vε such that:

V ₆ = V ₃ + W = W + I l / k We will now explain in more detail certain features of the process according to the invention. FIG. 5 schematically illustrates the production, on the output belt 26 of the spreader-lapper which is not entirely shown, of a sheet 67 by means of a covering veil 16 whose surface weight varies thanks to to an adjustment made in card 1 which also is only partially shown.

In this example, we describe to simplify the case where the covering veil 16 is obtained - from a single elementary veil 15 whose surface weight is adjusted by variation of the rotational speed of the doffer 13. Firstly also, it will be considered that there is no element between the comber 13 and the lapping carriage 27 of the spreader-lapper, such as a condenser or the like varying the surface weight and / or the speed of movement of the web 15, 16 It is also assumed that the speed V ₃ at which the web 16 is unwound through the lapping carriage 27 is permanently equal to the absolute value of the speed W of translation of the lapping carriage, so that no stretching or compression takes place. occurs at the time of deposition on the output belt 26. The sheet 67 is generally intended to be consolidated in a consolidation machine such as for example a needling machine which must produce a continuous textile product 68 on an output belt 69 of the consolidation machine or other suitable support. For the purpose of illustration, the thickness of the product 68 has been greatly exaggerated with respect to the width shown. It is also illustrated that the consolidated product 68 is a little narrower than the ply 67 as a result of a certain shrinkage which, in known manner, is generated by the needling process. In this example, the invention aims to manufacture a textile product having, over part of its width from one edge, a relatively thick zone 681, over another part of its width from the other edge, a zone 682 thinner, and between them a transition zone 683. Such a textile product can be useful for certain applications, in particular for floor mats used in the automobile, the part 682 thinner, therefore less robust, serving to garnish areas less exposed to wear, such as the vertical part going up towards the door sill. According to the invention, the speed of the doffer 13 is adjusted so that each section of sail takes, at the place where it undergoes the adjustment of surface weight, a value of surface weight corresponding to that which will be desired taking into account the position where the lapping carriage 27 will be located along its reciprocating travel when this same section is in turn deposited by the lapping carriage.

For this, account is taken of the cumulative length of veil that there is between the section Si being deposited on the output belt 26 (or more exactly on the segment of veil 71 previously deposited from the web 67) , and section S2, the surface weight of which is being determined by the speed of the doffer 13 at the instant considered. As the web 15, 16 is in this example transported and deposited without compression or extension of any kind along the path that section S2 will travel until it is deposited on the sheet already formed, this length of sail is equal to the total length of a certain number, in general non-integer, of strokes of the lapping carriage 27. It can thus be known that the lapping carriage 27 will have, when the section S ₂ is being deposited, a position that can be provided, for example position 27a in the situation shown in FIG. 5. This position 27a is shown in dotted lines, it corresponds to a determined surface weight and therefore the speed of motor 14 is controlled to that this surface weight is achieved by the doffer 13 in section S ₂ .

To determine the length of sail 15, 16 between sections S ₁ and S ₂ , the control unit 61 takes account of the respective positions of the carriages 27 and 29. It knows these positions from the angular positions of the motors 52 and 56 which control the position of the carriages 29 and 27 respectively. With this information, the control unit 61 is capable of calculating the length of sail 15, 16 between the sections Si and S ₂ even if this length varies. We have seen that this length could vary to allow the input speed Vi and / or the speed V ₃ to vary.

We will therefore, as shown, produce a web 15 having longitudinal regions 151 of relatively large thickness intended to form part of the area 681 of the finished product, and having a length twice the width of the corresponding area 671 of the web 67, alternating with zones 152 of smaller thickness having a length twice the width of the corresponding zone 672 of the ply 67, separated by transition zones 153 which are stacked in the zone 673 of the ply 67.

If, as a variant, the web 15, 16 undergoes at a point in its path between the sections S ₂ and If a drawing operation (true drawing or compression) with a drawing factor k ₂ as indicated in point 71, the entire length between section S ₂ and point 71 must be taken into account not for its actual value but for a value corrected corresponding to the actual length multiplied by the factor k ₂ .

For example, if k ₂ = 1.1 (actual stretch of + 10%), the entire length between section S ₂ and point 71 should be counted with an increase of 10%. This method of calculation is particularly involved when condensers ^' intervene downstream from the point where the areal weight adjustment is carried out.

In the example of FIG. 6, two arrangements are illustrated, independent of each other, with respect to the example of FIG. 5.

According to a first arrangement, a method is explained for adjusting the surface weight in a coordinated manner on two elementary webs 15a and 15b which contribute, both in the same proportions, in each cross section of the web 16, to create variations in thickness. desired for the web 16 along its length.

In a first variant of the first arrangement, it is assumed that the surface weight of each of the webs 15a and 15b is modified by variation of the spacing between each comber 13a or 13b and the drum 4. It is further assumed that the sections S2 of the web 15a and S3 of the web 15b which undergo the surface weight adjustment are separated by lengths of web different from the section Si undergoing the deposition. It is intended according to the invention to calculate these two delay lengths separately and to control the two adjustment members, that is to say in the example the two combers 13a and 13b, in a differentiated manner so that the thickness variations produced coincide with each other when the two elementary webs are superimposed at 72 so that the covering web 16 has the desired surface weight at the time of deposition on the web 67 at each point. In the case shown where it is sought that the two elementary webs 15a and 15b vary by achieving at every point in the length of the covering web each a constant proportion of the surface weight of the web covering 16, it is understood that the elementary veil having the longest path to travel undergoes in time advance over the other each modification of thickness desired for the covering veil 16. Even if the modifications desired for one and the other elementary veil result in each elementary veil 15a or 15b producing a variable proportion of the surface weight of the covering veil 16 along the length of the latter, it will be understood that the surface weight of the elementary veil having the longest distance to travel must be set with greater temporal anticipation than the other elementary veil. The difference between the commands applied to the two combers 13a and 13b therefore appears to be a time difference, although this difference must possibly vary if the speed at which the web 16 enters the spreader varies and / or if the speed to which the veil is deposited on the sheet 67 already formed varies.

In a second variant of the first arrangement, which will only be described for its differences from the first variant, it is assumed that the surface weight of each of the elementary webs 15a and 15b is modified by variation of the speed of rotation of the associated painter 13a or 13b. In addition, it has been arranged that the two elementary webs have between the section S ₂ or respectively S ₃ undergoing adjustment, and the section Si being deposited, substantially the same length of delay. This is true at all times since possible variations due to the movements of the accumulator carriage 29 affect the two delay lengths in the same way. The two elementary webs 15a, 15b always contribute in the same proportion to the surface weight of the covering web 16. Under these conditions, the motors 14a and 14b are controlled so that the rotational speeds of the two combers 13a and 13b undergo variations which are at each instant in the same proportion to each other, so that the production speeds of the elementary webs 15a and 15b are, at each instant, substantially equal to each other. Thus, at station 72, the two elementary webs 15a and 15b arrive at the same speed, which varies over time, and it is at all times possible, in particular by appropriate control of the movement of the accumulator carriage 29, to give the section d input 23 of the front belt 24 of the spreader-lapper (FIG. 4) a speed corresponding to the speed of arrival of the web 16 at this instant. Depending on the configuration of the card, the special feature of equalizing the two delay lengths as much as possible can be achieved by adjusting the surface weight of each sail with different means, respectively. One can for example adjust the speed of the doffer for one of the elementary veils, and the speed of rotation of a condenser for the other elementary veil.

The other arrangement, also illustrated in FIG. 6 but independent of the use of two elementary webs 15a and 15b, relates to the production of thinned edge zones 674 -and 676, for example to compensate for a conventional defect in thickening of the zones of edges 684 and 686, produced by the needling. With the thinned edge zones 674 and 676 of FIG. 6, these extra thicknesses are eliminated and the profile of the edge zones of the needled product takes the form shown in phantom in FIG. 5.

To produce such edge zones, it is possible, for example by means of an appropriate control of the motor 14a and / or of the motor 14b, to modify correspondingly the longitudinal profile of at least one of the elementary webs 15a and 15b. It is also possible to create in these zones a reduction in the speed V ₃ of unwinding of the web by the lapping carriage 27, with respect to the absolute speed | w I of the lapping carriage, this reduction being increasingly strong up to the reversal of the direction of travel of the lapping trolley 27 then gradually reducing to disappear when the lapping trolley 27 crosses the limit separating the area of edge 674 of the thick zone 671 and respectively the limit between the edge zone 676 and the relatively thin zone 672.

When the web is thus deposited on the sheet 67 already formed with a stretching factor which is different from 1 over at least part of the stroke of the lapping carriage, one of the possible calculation methods for determining the thickness settings to give to sections S2 and S3 consists in reasoning in fictitious strokes of the lapping carriage 27. A fictitious stroke is that which the lapping carriage would have carried out if it had moved at every moment with a speed whose absolute value | w I would have was equal to the speed V ₃ of unwinding of the web at the point considered. In addition, a central table 61 is created in correspondence between each point of the fictitious course, each point of the real course and the desired surface weight for the covering veil, before stretching, at each of these points. We calculate the delay length for sections S2 and S3 respectively undergoing the adjustment, we convert these delay lengths into the number of fictitious strokes, and we interpret the decimal part of this number to know the fictitious position or positions that the carriage will have lapper when it deposits sections S ₂ and S ₃ . The surface weight to be given to each of the sections S ₂ and S ₃ is then deduced from the correspondence table.

Of course, the invention is not limited to the examples described and shown. It is possible, in very many different ways, to combine different surface weight adjustment modes which have been described by way of examples. The invention can be used to produce, using the adjustment means provided in the card, a sheet profile which is simply intended to compensate for the excess thickness defects at the edges introduced into the needling machine or other consolidation machine, or in certain types. of less sophisticated design capable of controlling the speed of unwinding of the web at all points of the course of the lapping carriage.

It may be advantageous, in the case of a card producing at least two elementary webs such as 15a and 15b, to produce different longitudinal profiles for these two webs. For example, in the example of FIG. 6, the adjustment made on the veil 15b could be used to produce the two zones 671 and 672 of different thickness as well as the transition zone 673 and the veil 16a could undergo the adjustments producing the thinned edges 674 and 676.

Since it is preferred according to the invention to control the whole process according to the real or fictitious position of the lapping carriage at all times, and according to the position taken correlatively by the accumulator carriage 29, it is also preferred that the control unit 61 of the spreader-lapper has a master role in the implementation of the method. This control unit 61 sends to the sail production machine and in particular to its control unit 62 instructions which the control unit 62 transforms into commands applied to the engine (s) affecting the adjustment of the surface weight of the or elementary sails. But it could also be conceived that the programming takes place on the control unit 62 of the sail production machine, which could then, at any time, call from the control unit 61 of the spreader-lapper the information whose it would need to determine at all times the commands to be applied, in particular the information relating to the position of the two carriages 27, 29.

It is also conceivable that the two control units 61, 62 are grouped into a single one, the machine for producing the sail and the spreader-lapper then forming, conceptually, only one machine.

In certain installations, in particular when the sail production machine is pre-existing, the control unit 62 may take, at least in part, the form of an added intermediate module, capable of taking into account and to inject into the control circuit of the production machine variable instructions for the motors affecting the surface weight adjustment. Alternatively, the control unit 61 may include outputs capable of being directly connected to the sail production machine.

The invention makes it possible to carry out any kind of profiling, in particular with more than two zones of different thicknesses over the width of the sheet, or with a profile of thickness which varies all along at least one zone or all. of the width of the web, to produce a profile which can be concave, convex or alternately concave and convex.

The invention is not limited to assemblies in which possible variations in the speed of production of the web are compensated for by variation of an accumulation in one spreader-lapper. It is also possible to vary the working speed of the whole spreader-lapper, and for example to create a variable accumulation downstream of the spreader-lapper or to vary the speed of the following machines accordingly , such as a needling machine.

Claims

CLAIMS 1- Method for producing a textile sheet (67), in which at least one elementary veil is produced (15, 15a, 15b) then by means of a spreader-lapper (2) a covering veil (16) is folded , incorporating said elementary web, alternately in one direction and in the other on a transverse output belt (26) of one spreader-lapper, characterized in that by modifying at least one adjustment upstream of the spreader-lapper (2) the covering veil (16) introduced into the spreader-lapper is given a surface weight which varies according to the longitudinal direction of the covering veil so that the lap (67) obtained at the outlet of the spreader-lapper has a substantially predetermined surface weight distribution over its width. 2- A method according to claim 1, characterized in that the setting that is modified upstream of the spreader-lapper comprises an adjustment affecting a card (1) in an area located downstream of a drum (4) of the card, relative to the direction of transit of the fibers (11, 16) in the card, and independently of the speed of rotation of a doffer (13; 13a, 13b) taking the fibers (11) from the card drum (4) intended to constitute the elementary veil (16, 16a, 16b).

3- A method according to claim 1, characterized in that to modify said setting, a spacing (E) is modified between a card drum (4) and a doffer (13) removing fibers (11) from the drum intended to constitute the elementary veil (16).

4- Method according to claim 1, characterized in that the setting that is modified upstream of the spreader-lapper comprises an adjustment affecting a speed of transit of the fibers in a card (1) upstream of at least one doffer (13, 13a, 13b) of the card.

5- Method according to claim 4, characterized in that the speed of rotation of a drum (4) of the card 1 is varied. 6- A method according to claim 1, characterized in that an instantaneous speed (Vi) of input into the spreader-lapper (2) fluctuates as a function of an arrival speed of the lapping web, which is influenced by the setting that is modified upstream of the spreader, and in that one compensates for the differences between the instantaneous speed (Vi) of entry into the spreader and the instantaneous speed (V ₃ ) at which the spreader unwinds the covering veil (16) by adjusting at all times the length of a course of accumulation of veil in the spreading spreader.

7- Method according to one of claims 1 to 6, characterized in that to modify the surface weight of the elementary veil is modified with respect to the speed of a card doffer (13, 13a, 13b) the speed of minus a condenser member (17, 18) placed downstream of the doffer.

8- Method according to one of claims 1 to 7, characterized in that to modify the surface weight of the elementary veil is modified with respect to the speed of a card doffer (13, 13a, 13b) the speed of a detacher (19a, 19b) delivering the elementary web (15a, 15b) at the outlet of the card (1).

9- Method according to one of. Claims 1 to 8, characterized in that, in order to modify the surface weight of the elementary veil, the speed of a detacher (19b) delivering the elementary veil (15b) at the output of the card is modified, relative to the speed of transit of the fibers defined by a condenser member (18) receiving fibers taken from a card comber (13b).

10- Method according to one of claims 1 to 9, characterized in that according to the length of sail between a first section of sail (SI) being deposited on the output belt (26) in 1 'spreader-lapper (2) and a second sail section (S2, S3) located at the point of the path of the fibers where said adjustment influences the surface weight of the elementary sail (15, 15a, 15b) upstream of the spreader - lapper, we determine the point (27a) of the width of the sheet where the second section will be deposited (S2, S3) and said adjustment is made according to the surface weight programmed for said point of the width of the sheet.

11- Method according to claim 10, characterized in that to determine the point of the width of the sheet where the second section of the web will be deposited, account is taken of at least one stretching factor (k, k2) applied to the veil downstream of said point of the fiber path.

12- Method according to claim 10 or 11, characterized in that programs at least by zones (671,

672, 673) the distribution of the surface weights desired for the covering veil (16) arriving in a lapping carriage (27) of the spreader-lapper at each point of a course of the lapping carriage, and according to this program , a control device (61, 62) sends information or instructions at each instant on said adjustment to be made upstream of the spreader-lapper (2) at this instant.

13- Method according to one of claims 1 to 12, characterized in that one produces the covering veil (16) by superimposing at least two elementary veils (15a, 15b), and in that one modifies said differently adjustment for each of the elementary sails.

14- The method of claim 13, characterized in that one modifies said setting according to laws offset from one another said setting for each of the elementary webs respectively.

15- A method according to claim 13, characterized in that the constant setting is left for one of the elementary sails. 16- Method according to one of claims 13 to 15, characterized in that the setting that is changed upstream of one spreader-lapper has no effect on the speed of production of elementary webs.

17- The method of claim 13, characterized in that the setting that is changed affects the speed of production of elementary sails, in that it changes adjustment so that the production speeds of the elementary webs (15a, 15b) are equal to each other at all times, and in that the web lengths each comprised between a first web section (Si) being deposited on the outlet belt (26) in the spreader-lapper and a second section of web (S ₂ , S ₃ ) located at the point of the path of the fibers where said adjustment influences the surface weight of a respective elementary web (15a , 15b) are, at each instant, substantially equal to each other. 18- Method according to one of claims 1 to 17, characterized in that the surface weight distribution is predetermined over the width of the web (67) so that a consolidated textile product (68) obtained at the outlet of at least one consolidation machine placed downstream of the spreader-lapper (2) has a surface weight distribution varying at least by zones (681, 682, 683) over the width of the consolidated textile product.

19- Device for implementing a method according to one of claims l to 18, comprising a card (1) incorporating at least one leveling means in operation, under the action at least indirect of a programmable control (61, 62), of the thickness of at least..an elementary veil (15, 15a, 15b) produced in a veil production path, characterized in that this adjustment means is chosen from: - a means adjusting a distance (E) between a doffer (13) and a drum (4) of the card (1),

- a means of adjusting the speed of rotation of a condenser (17, 18) relative to the speed of rotation of the doffer (13) of the card, - a means of adjusting the speed of rotation of a detacher (19 , 19a, 19b) relative to the speed of rotation of a fiber transfer member, such as a doffer (13, 13a) or a condenser (17, 18), located immediately upstream; - A means for adjusting the speed of a fiber transfer member (4, 7) located upstream of the comber. 20-Device according to claim 19, characterized in that the card comprises at least two sail production paths to produce two elementary webs (15a, 15b) intended to be superimposed. 21- Device for implementing a method according to one of claims 1 to 18, comprising at least two production paths of elementary veil which then meet at a superposition station (72) of the two sails, characterized in which it further comprises at least one means for adjusting, in operation, under the action of a programmable control (61, 62), the surface weight of at least one of the elementary webs (15, 15a, 15b ), so that a covering veil (16) obtained by superposition of the elementary veils has a surface weight which varies according to its longitudinal direction.

22- Device according to claim 20 or 21, characterized in that it comprises at least one adjustment means for each sail production path, and in that the programmable control (61, 62) actuates, at least indirectly, the two means of adjustment in a different and coordinated manner.

23- Device according to claim 22, characterized in that the programmable control (61, 62) actuates, at least indirectly, the two adjustment means with a time offset such as sections of elementary sail (15a, 15b) having weights Surfaces similarly affected by the adjustment are superimposed in the covering veil (15).

24- Device according to claim 22 or 23, characterized in that the adjustment means are of different type for each of the two paths.

25- Device according to one of claims 17 to 21, characterized in that the means for adjusting one of the paths is a means for adjusting the speed of rotation of a doffer (13a, 13b) relative to the speed of rotation of a card drum (4). 26- Device according to one of claims 17 to 25, characterized in that the second production path keeps the thickness of the corresponding elementary web constant during operation. 27- Device according to one of claims 17 to 21, characterized in that it comprises for each path of production of elementary sail an adjusting means affecting the speed of production of each elementary sail, in that a length of sail between the section (SI) being deposited on the output belt (26), and each section (S ₂ , S ₃ ) undergoing the weight adjustment is the same for all the elementary webs, and what the programmable control (61, 62) actuates, at least indirectly, the two adjustment means so that the production speeds of the elementary webs are at each instant equal to each other.

28- Device for implementing a method according to one of claims 1 to 18, comprising: an apparatus for producing at least one elementary veil, including means for adjusting the surface weight of at least one veil elementary (15, 15a, 15b) produced,

- a spreader-lapper (2) rece _. in front of a covering veil (16) incorporating said at least one elementary veil and leading the covering veil along a path of variable geometry to a lapping carriage (27) movable back and forth transversely above a mat outlet (26), and

- a programmable control (61, 62) capable of sending at least indirectly to said adjustment means a signal for controlling the surface weight to be given to the elementary web (15, 15a, 15b) at each instant as a function of the position of the lapper carriage , characterized in that the programmable control (61, 62) comprises means for taking into account the length of the sail between a first section (SI) of sail being deposited on the exit belt (26) of the spreader-lapper (2) and a second section (S2) of sail undergoing the adjustment, and a total distance that the lapper carriage will have to travel to deposit this length, to determine the point (27a) of the width of the lap where the second section (S2) of sail will be deposited, and to form said control signal in function of the desired surface weight for the web (67) at point (27a) of the width of the web where this second section of the web will be deposited.

29- Device according to claim 28, characterized in that when taking into account said length of sail and said total distance, the programmable control takes into account at least one drawing factor (k, k2) undergone by the sail downstream of the area where said adjustment is made.

30- Device according to claim 28 or 29, characterized in that when taking into account said length of sail and said total distance, the programmable control takes into account a succession of stretching factors (k) undergone by the lapping veil (16) at each position of the lapping carriage (27) due to a variable difference between the speed (W) of movement of the lapping carriage and the speed (V ₃ ) at which the lapping carriage (27) unwinds the topping web (16) on the outlet belt (26).

31- Device according to one of claims 28 to 30, characterized in that when taking into account the length of the sail, the programmable control takes into account the position of an accumulator carriage (29) provided in 1 spreader -tapper (2) to vary over time the length of sail accumulated in one spreader-lapper (2).

32- Device for the implementation of a method according to one of claims 1 to 18, comprising: - a spreader-lapper (2) including a lapper carriage (27) movable back and forth transverse below an exit belt (26), and an accumulation means (29) for defining the length of a covering veil (16) accumulated in the spreader-lapper; and - an apparatus (1) for producing at least one elementary veil (15, 15a, 15b) for composing the covering veil (16) sent to the spreader-lapper, characterized in that the apparatus (1) includes for adjusting the surface weight of the elementary veil an adjustment means producing a fluctuation in the speed of production of the elementary veil (15, 15a, 15b), and in that the device comprises means for making the speed (Vi ) entry of the covering veil (16) into one spreader-lapper.

33- Device according to claim 32 characterized by means for controlling the accumulation means (29) so as to vary the length of sail accumulated in one spreader-lapper (2) as a function of the difference between the instantaneous speed ( Vi) of entry of the covering veil (16) into one spreader-lapper (2) and the instantaneous speed (V ₃ ) at which the lapping carriage (27) unwinds the covering veil (16) on the output belt (26).

34- Device according to claim 33, characterized in that the speed (V ₃ ) at which the lapping carriage (27) unwinds the lapping veil (16) on the output belt (26) is in a variable relationship with the speed (W) movement of the lapper carriage.

35- Device according to claim 33 or 34, characterized in that it comprises a control unit (61,

62) which includes:

- Means (61, 62) for programming a distribution of the surface weight over the width of the sheet to be produced; - Means for knowing at all times the length of lapping veil accumulated in one spreader-lapper (2), respectively the point of the back and forth stroke of the lapping carriage where the section (S2, S3) of veil will be deposited elementary undergoing the effect of the thickness adjusting means; - Means for controlling the adjustment means of the sail production apparatus (1) according to the surface weight programmed at said point of the width of the sheet;

- Means for controlling the accumulation means (29) as a function of the input speed (Vi) of the covering veil (16) which results from the control applied to the adjustment means of the apparatus (1).

36- Device according to claim 32, characterized in that the means for causing the input speed to fluctuate (Vi) are means for causing the running speed of the assembly of the spreader-lapper to fluctuate.