Patent Description:
In particular, disclosed herein are a crosslapper for a card web and a method for crosslapping a card web.

The crosslapper of the present invention can be used in a textile production line, included at the exit of a carding plant, e.g. a line for processing fibres to be used for manufacturing semifinished products, commonly referred to as non-woven fabrics, or simply as nonwovens, to be subsequently used in many applications.

Nonwovens are obtained by processing fibres, generally synthetic ones, in carding machines. Carding machines for nonwoven production process the fibres to produce a web formed by the cohesion of the fibres themselves. The strength properties of such a web are insufficient for use in many fields, and therefore thicker webs are produced, having better mechanical strength properties, by coupling multiple webs together by layering. Such coupling by layering is effected directly at the exit of the carding plant by subjecting the web to a crosslapping action that causes the web exiting the carding machine to be overlapped into multiple layers. The crosslapping action is performed by a machine called crosslapper. Current crosslappers, e.g. like the crosslapper described in European patent <CIT>, generally consist of movable carriages whereon two conveyor belts are fixed which, through the reciprocating motion of the movable carriages, cause the web exiting the carding machine to be overlapped into multiple layers. The use of a pair of carriages makes it possible to store the web in the upper carriage (compensator carriage) during the step of reversing the lower carriage (layering or distributor carriage).

Another example of a crosslapper known in the art is shown in European patent <CIT>, wherein a crosslapper for a card web comprises:.

Document <CIT> discloses a machine to form carded webs. The machine has a system of continuous belts and trolleys. The belts are close together to carry the web at the upper channel between the first two belts to the lower channel across the first trolley, which is also defined by the first two belts to deliver the web to a conveyor.

Document <CIT> describes an assembly to lay the webs from a carding machine, in laying widths, having a delivery belt, several main trolleys and two continuous conveyor belts over the main trolleys. At least one support trolley supports a conveyor belt level with a number of deflection rollers for the conveyor belt levels. The belt entry and exit are generally at the same height level. At least three deflection rollers have their axes on a triangle or a polygon, forming an omega-shaped guide for the lower levels of both conveyor belts. The web layer has two support trolleys, each at a lower belt level of the two conveyor belts. The web layer has at least one self-standing and mobile support trolley, near the lower main trolley, with a drive link to the upper main trolley. The web layer has a support trolley, which is integrated with the upper main trolley. The web layer has at least one mobile tensioner trolley for at least one conveyor belt, with a drive link to at least one of the main trolleys. The assembly can have at least one additional self-standing support trolley, at one of the belt tensioner trolleys, with a drive link to a main trolley.

The crosslappers known in the art suffer from a number of drawbacks, which will be illustrated below.

A first drawback is related to the asymmetric motion of the conveyor belts. This implies less tension in the web, which, prior to entering the unloading cylinders, is dropped (or abandoned) in a downward section, the angle of which varies according to the crosslapper type and/or configuration.

Another problem is due to the formation of turbulences in the abandoned web, generated by air mass movements caused by the moving parts of the crosslapper. This results in poor quality of the layered material (called mat), which will typically suffer from bubbling and stretching.

Another drawback is related to the inertia of the abandoned web, which results in the mat being thicker in particular along the edges, where reversal of the motion of the layering carriage occurs.

A further drawback comes from the necessity of reducing the speed of the crosslapping operation in order to be able to better control the inertia effects of the abandoned web while reversing the motion of the layering carriage.

Another problem relates to the need to remove the most dense parts from the mat, and keep only the most homogeneous part of the mat. This necessarily implies the introduction of an additional step, i.e. a trimming step, in the mat production process, downstream of the crosslapping operation. Such step consists of removing the side edges of the mat exiting the crosslapper wherever the density of the mat is different (generally higher) than in the central area of the same. Typically the edges need to be trimmed by a width of approximately <NUM> to <NUM> per side: this results in a total scrap amount of <NUM>-<NUM>, which, considering an average mat width of <NUM>, is <NUM>% on average.

It is therefore one object of the present invention to solve these and other problems of the prior art, and in particular to provide a crosslapper and a crosslapping method that allow moving the belts transporting the card web in such a way as to effectively keep the web under tension.

It is a further object of the present invention to provide a crosslapper and a crosslapping method that prevent the effect of turbulences on the card web, thus improving the quality of the manufactured product.

It is another object of the present invention to provide a crosslapper and a crosslapping method that allow obtaining a mat having a uniform thickness, particularly at the edges where reversal of the motion of the layering carriage occurs.

It is a further object of the present invention to provide a crosslapper and a crosslapping method that allow increasing the mat production rate by increasing the speed of the crosslapping process.

It is a further object of the present invention to provide a crosslapper and a crosslapping method that ensure less mat production scraps, thereby increasing the profitability of the textile production line.

The invention described herein consists of a crosslapper and a related crosslapping method that comply with two antithetical operating constraints, i.e.: the card web must be fed in at a constant speed, equal to its speed as it exits the carding machine; the material cannot exit at a constant speed, since the layering carriage must necessarily move in a reciprocating manner in order to deposit the various layers.

The principle of operation of the present invention is based on a symmetric structure in which one carriage slides within two looped conveyor belts, commonly called tables, while ensuring a constant tension of the card web.

Further advantageous features of the present invention are set out in the appended claims, which are an integral part of the present description.

The invention will now be described in detail through some non-limiting exemplary embodiments thereof, with particular reference to the annexed drawings, wherein:.

With reference to <FIG>, there is schematically shown a crosslapper <NUM> for a card web <NUM> according to one embodiment of the present invention.

The crosslapper <NUM> can be installed downstream of a carding machine in a textile production line.

The crosslapper <NUM> may be inserted in new carding lines or, alternatively, with just a few adaptations, in existing carding lines as a replacement for current crosslappers, thus improving the performance of existing plants.

The carding machine outputs a card web <NUM>, which may be, for example, a non-woven web. The card web <NUM> exiting the carding machine at a constant speed is fed into the crosslapper <NUM> by means of, for example, at least one feeding rotary cylinder <NUM>.

Said crosslapper <NUM> for a card web <NUM> comprises a first conveyor belt <NUM> and a second conveyor belt <NUM>, both arranged in a closed-loop configuration. Said conveyor belts are configured to overlap each other in at least one conveyor belt portion and are adapted to define a conveyance channel <NUM> for said card web <NUM>. In this manner, an inlet zone <NUM> and an outlet zone <NUM> for said web card <NUM> are defined in the conveyance channel <NUM>. Said first conveyor belt <NUM> and second conveyor belt <NUM> are made of substantially inextensible materials, e.g. canvas rubber and/or metal-core rubber, and can be wound, even only partially, on fixed and/or self-moving rotary cylinders (or rollers), which are in turn supported by the structure of the crosslapper <NUM>, e.g. a steel and/or iron metal structure. The rotary cylinders make it possible to move said first conveyor belt <NUM> and second conveyor belt <NUM> inside the crosslapper <NUM> and may be free to rotate and/or may be driven by actuator means, e.g. electric motors and/or electrovalves.

The actuator means are coupled to said rotary cylinders via coupling means, e.g. belts, arms, pistons and/or pulleys.

The position and trim of one or more rotary cylinders inside the crosslapper <NUM> can be modified via said actuator means and coupling means, e.g. arms operated by electric motors or pistons controlled by means of electrovalves.

The crosslapper <NUM> may further comprise sensor means for detecting the position of its moving parts, or other types of sensor means adapted to monitor production quality and/or quantity, e.g. sensors measuring the speed of the card web <NUM> and/or of said first conveyor belt <NUM> and second conveyor belt <NUM>.

The crosslapper <NUM> is provided with a control unit <NUM> adapted to control the actuator means of the crosslapper <NUM> and adapted to receive data from the sensor means of the crosslapper <NUM>.

The control unit <NUM> may comprise a processing module, a memory module, an input/output module, a communication module, an interface module and one or more buses mutually connecting said modules; said control unit <NUM> may be, for example, a PLC, an axis control system or a computer.

The memory module may consist of an electronic memory like, for example, a solid-state flash memory, which stores information and instructions implementing the present embodiment of the invention. Such information may concern, for example, the position and the revolution speed of the rotary cylinders. The instructions stored in the memory module will be described in detail later on with reference to the flow chart of <FIG>.

The processing module is constructed by using electric components such as, for example, microcontrollers or processors with an ARM architecture. The processing module processes the information and the instructions stored in the memory module.

The input/output module handles, respectively, the input devices, e.g. the sensor means, and the output devices, e.g. the actuator means.

The interface module allows users and/or service technicians to interface with the crosslapper <NUM> in order to control its functions and/or verify its operating state.

The communication module provides communication with a remote management system for managing the crosslapper <NUM> and/or the textile production plant in which the crosslapper <NUM> is included. Said communication module may comprise, for example, a Wi-Fi, GSM or ETHERNET module. Therefore, connections to the remote management system are available both in wired and wireless mode.

In another embodiment of the invention, the crosslapper <NUM> can interact with the other machines normally included in the textile production cycle via sensor means adapted to detect parameters that, after having been appropriately processed, make it possible to improve the evenness of the product exiting the carding machine and during the next processing steps, e.g. needle looming, quilting, calendering, etc..

For example, the crosslapper <NUM>, arranged upstream of needle looming machines along the textile production line, may comprise sensor means adapted to measure the thickness, and hence the density, of the final material exiting the needle looms throughout its width; said sensor means may be, for example, optical or X-ray scanners. This will allow the control unit to change, whether on average and/or locally, the density value of the layered material according to the speed of motion of the moving components of the crosslapper <NUM>, such as, for example, the rotary cylinders or the moving carriage <NUM>, which will be described in greater detail below.

Said crosslapper <NUM> comprises a collection surface <NUM> adapted to collect said layered card web <NUM>, a distributor carriage <NUM>, and may comprise first retriever means <NUM> and second retriever means <NUM>.

Said first retriever means <NUM> comprise at least one first rotary cylinder <NUM>, whereon the first conveyor belt <NUM> is at least partly wound. Said at least one first rotary cylinder <NUM> is adapted to create one or more mobile loops <NUM> of the first conveyor belt <NUM>, thus allowing it to be moved under tension. As the first conveyor belt <NUM> passes on at least one first rotary cylinder <NUM>, one or more mobile loops <NUM> of the first conveyor belt <NUM> can be formed within the crosslapper <NUM>. The extension (width) of said loops along a predetermined direction can be determined with respect to at least one fixed or self-moving element comprised in the crosslapper <NUM>, such as, for example, a pin or another rotary cylinder whereon said first conveyor belt <NUM> is at least partly wound. By moving said at least one first rotary cylinder <NUM> along said predefined direction, it is possible to vary the width of one or more loops, which are therefore referred to as mobile loops. Thus, the retriever means <NUM>, comprising components like rotary cylinders, pins and the like, permit adjusting the extension of the first conveyor belt <NUM> inside the crosslapper <NUM>, thereby causing it to be subj ected to an appropriate pull/tension, so that the card web <NUM> will be appropriately moved under tension to ensure a correct crosslapping process, as described by the present invention. In addition, with reference to the embodiment of the invention of <FIG>, the first rotary cylinder <NUM> may be operatively connected to a first actuator 171a and to a second actuator 171b adapted to tightly move the first conveyor belt <NUM> during the motion of the distributor carriage <NUM>. For example, the first actuator 171a may be operatively connected to a first end of the first rotary cylinder <NUM>, while the second actuator 171b may be operatively connected to a second end of the first rotary cylinder <NUM>, so as to move the first rotary cylinder <NUM> in an independent manner. The first actuator 171a and the second actuator 171b may be electric linear actuators, e.g. controlled by the control unit <NUM> so as to generate, respectively, a first tension T1 and a second tension T2 of the first conveyor belt <NUM>; in this way, it is possible to obtain a first average force F1 along a sliding direction of the first conveyor belt <NUM>, which can be calculated, for example, as F1=(T1+T2)/<NUM>, suitable for keeping the first conveyor belt <NUM> under tension.

Moreover, the first actuator 171a and the second actuator 171b may be adapted to move the first conveyor belt <NUM> along a first direction orthogonal to the sliding direction of the first conveyor belt <NUM>, so as to prevent the first conveyor belt <NUM> from rubbing against the structure of the crosslapper <NUM>.

For example, the first conveyor belt <NUM> can be moved along the first orthogonal direction, which may be coplanar with the first conveyor belt <NUM> itself, under a first differential force D1 that can be added to the first average force F1. Such first differential force D1 is generated by a difference between the first tension T1 caused by the first actuator 171a and the second tension T2 caused by the second actuator 171b, i.e. D1=T1-T2, and allows centering the first conveyor belt <NUM> on the first rotary cylinder <NUM> while preventing the first conveyor belt <NUM> from getting damaged by rubbing against the structure of the crosslapper <NUM>, e.g. two or more sidewalls of the crosslapper <NUM>.

In this manner, advantageously, the crosslapper <NUM> according to the present invention allows centering the first conveyor belt <NUM> without requiring the use of pneumatic centering units like those that are present on prior-art crosslappers.

Said second retriever means <NUM> comprise at least one second rotary cylinder <NUM> whereon said second conveyor belt <NUM> is wound, said at least one second rotary cylinder <NUM> being adapted to create one or more mobile loops <NUM> of said second conveyor belt <NUM> for tightly moving said second conveyor belt <NUM>. As previously specified, as the second conveyor belt <NUM> passes on at least one second rotary cylinder <NUM>, one or more mobile loops <NUM> of the second conveyor belt <NUM> can be formed within the crosslapper <NUM>. The extension (width) of said loops along a predetermined direction can be determined with respect to at least one fixed or self-moving element comprised in the crosslapper <NUM>, such as, for example, a pin or another rotary cylinder whereon said second conveyor belt <NUM> is at least partly wound. By moving said at least one second rotary cylinder <NUM> along said predefined direction, it is possible to vary the width of one or more loops, which are therefore referred to as mobile loops. Thus, the retriever means <NUM>, comprising components like rotary cylinders, pins and the like, permit adjusting the extension of the second conveyor belt <NUM> inside the crosslapper <NUM>, thereby causing it to be subjected to an appropriate pull/tension, so that the card web <NUM> will be appropriately moved under tension to ensure a correct crosslapping process, as described by the present invention. The number of mobile loops of said first conveyor belt <NUM> and said second conveyor belt <NUM> and their respective widths contribute to determining the correct feeding of the card web <NUM> in the conveyance channel <NUM>.

In addition, still with reference to the embodiment of the invention shown in <FIG>, the second rotary cylinder <NUM> may be operatively connected to a third actuator 172a and to a fourth actuator 172b adapted to tightly move the second conveyor belt <NUM> during the motion of the distributor carriage <NUM>.

For example, the third actuator 172a may be operatively connected to a first end of the second rotary cylinder <NUM>, while the fourth actuator 172b may be operatively connected to a second end of the second rotary cylinder <NUM>, so as to move the second rotary cylinder <NUM> in an independent manner. The third actuator 172a and the fourth actuator 172b may be electric linear actuators, e.g. controlled by the control unit <NUM> so as to generate, respectively, a third tension T3 and a fourth tension T4 of the second conveyor belt <NUM>; in this way, it is possible to obtain a second average force F2 along a sliding direction of the second conveyor belt <NUM>, which can be calculated, for example, as F2=(T3+T4)/<NUM>, suitable for keeping the second conveyor belt <NUM> under tension.

Moreover, the third actuator 172a and the fourth actuator 172b may be adapted to move the second conveyor belt <NUM> along a second direction orthogonal to the sliding direction of the second conveyor belt <NUM>, so as to prevent the second conveyor belt <NUM> from rubbing against the structure of the crosslapper <NUM>.

For example, the second conveyor belt <NUM> can be moved along the second orthogonal direction, which may be coplanar with the second conveyor belt <NUM> itself, under a second differential force D2 that can be added to the second average force F2. Such second differential force D2 is generated by a difference between the third tension T3 caused by the third actuator 172a and the fourth tension T4 caused by the fourth actuator 172b, i.e. D2=T3-T4, and allows centering the second conveyor belt <NUM> on the second rotary cylinder <NUM> while preventing the second conveyor belt <NUM> from getting damaged by rubbing against the structure of the crosslapper <NUM>, e.g. two or more sidewalls of the crosslapper <NUM>.

In this manner, advantageously, the crosslapper <NUM> according to the present invention allows centering the second conveyor belt <NUM> without requiring the use of pneumatic centering units like those that are present on prior-art crosslappers.

<FIG> schematically shows a detail of the crosslapper <NUM> of <FIG>, i.e. the distributor carriage <NUM>, according to the present embodiment of the invention. Said distributor carriage <NUM> comprises at least one first distributor cylinder <NUM>, whereon said first conveyor belt <NUM> slides, and at least one second distributor cylinder <NUM>, whereon said second conveyor belt <NUM> slides.

Said first distributor cylinder <NUM> and second distributor cylinder <NUM> define said outlet zone <NUM> for the card web <NUM>.

The distributor carriage <NUM> is adapted to move parallel to the collection surface <NUM> for depositing thereon the card web <NUM> in successive layers to form the mat. According to the present embodiment of the invention, the card web <NUM> is fed into the crosslapper <NUM>, e.g. by means of at least one inlet rotary cylinder <NUM> (shown in <FIG>) and is then transported, e.g. by means of the second conveyor belt <NUM>, towards the distributor carriage <NUM>. At this point, the card web <NUM> enters the conveyance channel <NUM> through the inlet zone <NUM> and exits the distributor carriage <NUM> through the outlet zone <NUM>. As it moves parallel to the collection surface <NUM> in a reciprocating manner along a direction parallel to the collection surface <NUM>, the distributor carriage <NUM> deposits the card web <NUM> in successive layers onto said collection surface <NUM> to form the mat.

Said distributor carriage <NUM> comprises at least one third distributor cylinder <NUM>, whereon said first conveyor belt <NUM> is wound, and at least one fourth distributor cylinder <NUM>, whereon said second conveyor belt <NUM> is wound. Said third distributor cylinder <NUM> and fourth distributor cylinder <NUM> are adapted to create one or more mobile loops <NUM> defined in at least one portion of said conveyance channel <NUM> for the card web <NUM>, positioned between said inlet zone <NUM> and outlet zone <NUM> by the distributor carriage <NUM>. This technical measure advantageously makes it possible to accumulate the card web <NUM> during the motion of the distributor carriage <NUM>.

With reference to <FIG>, there is schematically shown the principle of operation of the crosslapper <NUM> according to the embodiment of the invention of <FIG>, in three operating configurations thereof, respectively. The principle of operation of the present invention is based on a symmetric structure of the crosslapper <NUM> (i.e. a so-called "accordion" structure), wherein the distributor carriage <NUM> slides through said first conveyor belt <NUM> and second conveyor belt <NUM>, commonly referred to as tables.

The two tables always have a specular behaviour: when the first table becomes longer, the second table becomes shorter, and vice versa. The lengthening and shortening of the tables is made possible by the synchronous motion of one or more mobile loops, which follow the development of both tables, which are substantially inextensible, while ensuring a constant tension of the same.

The reciprocating motion of said third distributor cylinder <NUM> and fourth distributor cylinder <NUM> advantageously ensures an adequate accumulation of the card web <NUM> by means of one or more mobile loops <NUM> generated during the motion (acceleration/deceleration) of the distributor carriage <NUM>. This results in the card web <NUM> being subjected to appropriate pull/tension for a proper crosslapping process, without the web being abandoned inside the distributor carriage <NUM>.

<FIG> respectively show a first and a third operating configuration of the crosslapper <NUM> according to the present embodiment of the invention, wherein said at least one first rotary cylinder <NUM> is moved in such a way as to increase the width of the mobile loops <NUM> of said first conveyor belt <NUM> when said at least one second rotary cylinder <NUM> is moved in such a way as to decrease the width of the mobile loops <NUM> of said second conveyor belt <NUM>, and vice versa (<FIG>).

In said first operating configuration of the crosslapper <NUM>, the third distributor cylinder <NUM> and the fourth distributor cylinder <NUM> are moved in such a way as to substantially increase the width of said mobile loops <NUM> defined in at least one portion of said conveyance channel <NUM> when said distributor carriage <NUM> is decelerating.

In said third operating configuration of the crosslapper <NUM>, the third distributor cylinder <NUM> and the fourth distributor cylinder <NUM> are moved in such a way as to substantially decrease the width of said mobile loops <NUM> defined in at least one portion of said conveyance channel <NUM> when said distributor carriage <NUM> is accelerating.

<FIG> shows a second operating configuration of the crosslapper <NUM> according to the present embodiment of the invention, wherein said third distributor cylinder <NUM> and fourth distributor cylinder <NUM> are moved in such a way as to substantially nullify the width of said mobile loops <NUM> defined in at least one portion of said conveyance channel <NUM> when said distributor carriage <NUM> is moving at a substantially constant speed.

With reference to the embodiment shown in <FIG>, the crosslapper <NUM> may additionally comprise a third conveyor belt <NUM>, arranged in a closed-loop configuration, adapted to slide on a driving rotary cylinder <NUM> operatively connected to a fifth actuator <NUM>, e.g. an electromechanical servomotor. Such driving rotary cylinder <NUM> can receive the card web <NUM> fed into the crosslapper <NUM>. The third conveyor belt <NUM> may be made of substantially inextensible materials, e.g. canvas rubber and/or metal-core rubber, and may be wound, at least partly, on at least one fixed and/or self-moving rotary cylinder or roller <NUM> that may be supported by the structure of the crosslapper <NUM>. Moreover, the third conveyor belt <NUM> is adapted to slide on at least a fifth distributor cylinder <NUM> and a sixth distributor cylinder <NUM> comprised in the distributor carriage <NUM>, so as to convey the card web <NUM> towards the inlet zone <NUM>. The third conveyor belt <NUM> overlaps in at least one further portion <NUM> the second conveyor belt <NUM> so as to define a confinement zone for said card web <NUM> upstream of the distributor carriage <NUM>, wherein the third conveyor belt <NUM> is adapted to be moved by said fifth actuator <NUM> in accordance with the motion of the distributor carriage <NUM>. Advantageously, this makes it possible to create a confinement zone between the third conveyor belt <NUM> and the second conveyor belt <NUM>, where the card web <NUM> is at least partly confined, which varies in accordance with the motion of the distributor carriage <NUM> effected, for example, by a fifth actuator <NUM>. Advantageously, from such confinement zone the card web <NUM> is evenly conveyed towards the inlet zone <NUM>, thus minimizing the adverse effects of any aerodynamic turbulences on the card web <NUM>.

With reference to <FIG>, there is schematically shown the principle of operation of the crosslapper <NUM> according to the embodiment of the invention of <FIG>, in three operating configurations thereof, respectively. As described with reference to <FIG>, the principle of operation of the present invention is based on a symmetric structure of the crosslapper <NUM> (i.e. a so-called "accordion" structure), wherein the distributor carriage <NUM> slides through said first conveyor belt <NUM>, second conveyor belt <NUM> and third conveyor belt <NUM>, commonly referred to as tables. The first conveyor belt <NUM> and the second conveyor belt <NUM> always have a specular behaviour: when the first table becomes longer, the second table becomes shorter, and vice versa, while the third conveyor belt <NUM> substantially follows the second conveyor belt <NUM>. The lengthening and shortening of the tables is made possible by the synchronous motion of one or more mobile loops, which follow the development of both tables, which are substantially inextensible, while ensuring a constant tension of the same.

With reference to <FIG>, the following will describe an exemplary method for crosslapping a card web, coming from a feeding assembly, in the crosslapper <NUM> according to the embodiment of the invention shown in <FIG>, wherein said crosslapper <NUM> comprises a movement phase, in which said distributor carriage <NUM> is moved parallel to said collection surface <NUM>.

Said movement phase is controlled by the control unit <NUM> in such a way that, during said movement phase, said first conveyor belt <NUM> and second conveyor belt <NUM> are tightly moved by at least one third distributor cylinder <NUM>, whereon said first conveyor belt <NUM> is wound, and by at least one fourth distributor cylinder <NUM>, whereon said second conveyor belt <NUM> is wound, wherein said third distributor cylinder <NUM> and fourth distributor cylinder <NUM> create one or more mobile loops <NUM> defined in at least one portion of said conveyance channel <NUM> for said card web <NUM>.

The third distributor cylinder <NUM> and the fourth distributor cylinder <NUM> are comprised in the distributor carriage <NUM>. During said movement phase, the width of the mobile loops <NUM> defined in at least one portion of the conveyance channel <NUM> is changed in such a way as to accumulate the card web <NUM> during the motion of the distributor carriage <NUM>. During said movement phase, when the width of the mobile loops <NUM> of the first conveyor belt <NUM> increases, the width of the mobile loops <NUM> of the second conveyor belt <NUM> decreases, and vice versa.

At step <NUM>, the crosslapper is initialized with no material, by positioning the distributor carriage <NUM> in proximity to the centerline of the machine and the other actuators in a consequent position, defined as a function of calculated laws of motion ("electronic cams").

At step <NUM>, the crosslapper is started, accelerating up to its normal speed (corresponding to the speed out of the upstream carding machine). In this phase, the machine is already completely synchronous: the control unit <NUM> moves all machine actuators according to calculated laws of motion ("electronic cams"). The distributor carriage <NUM> is moved by using a pseudo-trapezoid speed profile, which alternates constant-speed phases, deceleration phases and acceleration phases, while the other actuators are synchronized accordingly to perform the above-described movement phases.

At step <NUM>, the crosslapper <NUM> is completely synchronous and runs at a speed similar to the speed out of the carding machine. At this point, the web is loaded and the production process begins.

At step <NUM>, the crosslapper <NUM> is fully operational, and is ready to receive any changes to its operating parameters, e.g. the output layer width or the number of overlapped layers.

At step <NUM>, the control unit <NUM> verifies whether the crosslapping operation should continue or not based on a predefined criterion, e.g. the processing time and/or in response to a command generated, for example, upon an emergency signal issued while the crosslapper <NUM> is in operation. If so, the control unit will execute step <NUM>, otherwise it will execute step <NUM>.

At step <NUM>, the control unit <NUM> executes all the operations necessary for the crosslapper <NUM> to complete the crosslapping operation. During this step, the control unit may signal the idle state of the crosslapper <NUM>, e.g. by means of luminous indicators such as LED indicators, and/or audible signals, e.g. buzzers or loudspeakers.

As regards the embodiment shown in <FIG>, during the movement phase of the above-described method the first actuator 171a and the second actuator 171b operatively connected to the first rotary cylinder <NUM> cause the first conveyor belt <NUM> to move under tension during the motion of the distributor carriage <NUM>, and move the first conveyor belt <NUM> along the first direction orthogonal to the sliding direction of the first conveyor belt <NUM> so as to prevent the first conveyor belt <NUM> from rubbing against the structure of the crosslapper <NUM>.

In addition, during the movement phase of the above-described method the third actuator 172a and the fourth actuator 172b operatively connected to the second rotary cylinder <NUM> cause the second conveyor belt <NUM> to move under tension during the motion of the distributor carriage <NUM>, and move the second conveyor belt <NUM> along the second direction orthogonal to the sliding direction of the second conveyor belt <NUM> so as to prevent the second conveyor belt <NUM> from rubbing against the structure of the crosslapper <NUM>.

In addition, the third conveyor belt <NUM>, arranged in a closed-loop configuration, slides on a driving rotary cylinder <NUM> operatively connected to the fifth actuator <NUM>. The third conveyor belt <NUM> overlaps in at least one further portion <NUM> said second conveyor belt <NUM> so as to define a confinement zone for the card web <NUM> upstream of the distributor carriage <NUM>, wherein the third conveyor belt <NUM> is moved by the fifth actuator <NUM> in accordance with the motion of the distributor carriage <NUM>.

The advantages of the present invention are apparent from the above description.

The crosslapper and the crosslapping method of the present invention advantageously permit crosslapping a card web while keeping the web tighter, by symmetrically and synchronously moving the tables that transport the web.

The crosslapper and the crosslapping method of the present invention advantageously improve the quality of the manufactured product by reducing the effect of turbulences on the card web during the process.

Another advantage of the present invention lies in the fact that a mat is obtained which has a uniform thickness, due to the reduction of the turbulences to which the card web is subjected during the process.

The crosslapper and the crosslapping method of the present invention advantageously allow increasing the mat production speed, in that the crosslapping process can effectively control the card web so as to reduce any imperfections in the mat caused by the inertia of the card web.

A further advantage of the crosslapper and crosslapping method of the present invention lies in the fact that mat production scraps are reduced, since the mat exiting the crosslapper requires less trimming of its edges.

Claim 1:
Crosslapper (<NUM>) for a card web (<NUM>), comprising:
- a first conveyor belt (<NUM>) and a second conveyor belt (<NUM>), both arranged in a closed-loop configuration, overlapping each other in at least one conveyor belt portion and adapted to define a conveyance channel (<NUM>) for said card web (<NUM>), wherein an inlet zone (<NUM>) and an outlet zone (<NUM>) are defined for said card web (<NUM>);
- a collection surface (<NUM>) adapted to collect said layered web (<NUM>);
- a distributor carriage (<NUM>) comprising at least one first distributor cylinder (<NUM>), whereon said first conveyor belt (<NUM>) slides, and at least one second distributor cylinder (<NUM>), whereon said second conveyor belt (<NUM>) slides, wherein said first distributor cylinder (<NUM>) and second distributor cylinder (<NUM>) define said outlet zone (<NUM>) for said card web (<NUM>), said distributor carriage (<NUM>) being adapted to move parallel to said collection surface (<NUM>),
wherein said distributor carriage (<NUM>) comprises at least one third distributor cylinder (<NUM>), whereon said first conveyor belt (<NUM>) is wound, and at least one fourth distributor cylinder (<NUM>), whereon said second conveyor belt (<NUM>) is wound, wherein said third distributor cylinder (<NUM>) and fourth distributor cylinder (<NUM>) are adapted to create one or more mobile loops (<NUM>) in at least one portion of said conveyance channel (<NUM>) for said card web (<NUM>) in order to accumulate said card web (<NUM>) during the motion of the distributor carriage (<NUM>),
said crosslapper (<NUM>) being characterised in that said third distributor cylinder (<NUM>) and fourth distributor cylinder (<NUM>) are horizontally mobile with respect to said first (<NUM>) and second (<NUM>) distributor cylinder.