EA039952B1 - Apparatus for compacting a continuous textile substrate by means of elastic belt - Google Patents

Abstract

The invention relates to an apparatus for compacting a continuous textile substrate (T) by means of an elastic belt, comprising a heatable rotating cylinder (10); an endless belt (20) movable along a closed path (P) to support and transport the textile substrate (T) in contact with a side surface portion (11) of said heatable rotating cylinder (10), said belt being elastically deformable in elongation; a roller system (31, 32, 33, 34, 35) on which said belt (20) is wound in a state of pretensioning in elongation, wherein said roller system comprises a plurality of idle return rollers (33, 34, 35) and a plurality of motorized rollers (31, 32) which may be operated so as to slide said belt (20) along said closed path (PC), imposing on said belt an additional tensional state of elongation at a first section (T1) of said path which extends - with respect to a direction of advancement (X) of the belt - upstream of a second section (T2) of said path in which said belt (20) is kept in contact with the rotating cylinder; means (40) for guiding said textile substrate (T) between said belt (20) and said heatable cylinder (10) along said second section (T2) of said path. The apparatus comprises a system for reducing friction coefficient between the belt (20) and the heatable rotating cylinder (10), said system for reducing friction coefficient comprising one or more interposition tapes (61, 62; 63) between the belt and the cylinder.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a device for sealing a continuous textile substrate with an elastic band.

State of the art of the present invention

As is known, the process of compacting webs or textile substrates is one of the main processes in the field of finishing textile materials and has the aim of imparting stability to the webs before being sent to the production stage.

Generally, stability and densification of the web is achieved using a consolidated technology machine that uses a change in the curvature of the felt or rubber band on which the web is placed to effect densification. Changing the curvature of the backing (felt or rubber band) then causes a longitudinal contraction of the web, which is subsequently pressed using a hot cylinder that stabilizes the sealing effect, ensuring dimensional stability of the web after it exits the machine.

After manufacturing, all fabrics (including woven and knitted fabrics) require a stabilization and compaction process that makes them suitable for cutting and sewing. Thus, sealing machines are widely used in finishing processes. The resulting degrees of compaction depend on the initial degree of stability of the fabric produced. The initial degree of stability of the canvas, in turn, depends on the type of material from which it is made.

It is often necessary to repeatedly pass the same web through densification machines in order to obtain the desired densification results. This is the case, in particular, if the original web has a high degree of instability. All this increases processing time and affects production costs.

Thus, in the art there is a very urgent need to reduce the duration of the web densification processes, especially in the case of webs (for example, made from viscose), which are characterized by high degrees of initial instability.

Over time, various alternative technical solutions have been proposed, the purpose of which was to make sealing systems more efficient. However, these solutions were not fully satisfactory.

More specifically, the treatment for densification (or shrinkage) of the webs is carried out mainly by means of the so-called compression technique, which is based on the use of a highly deformable tape against which the web to be densified is pressed tightly. The deformation of the belt in the longitudinal direction of travel by means of a mechanical device suitable for the purpose consists essentially of a sequence of a first expansion stage and a second compression stage. In particular, during the compression stage, the web, firmly connected to the deformable surface of the tape, undergoes compression in the direction of travel, i.e. compaction of its structure and, ultimately, longitudinal shrinkage.

The deformability of the tape can be determined by the type and characteristics of the material from which it is made, as well as the type of mechanical stress produced on it by a mechanical device made with the possibility of its deformation. Thus, there are known deformations by pressing the tape, which cause it to stretch (elongate), followed by compression (contraction) in the original unstressed state; or deformations by changing the peripheral speed of the belt, resulting from its sliding on rollers or cylinders with different radii of curvature along an alternately convex and concave path, which causes an alternate increase (elongation) and a decrease (reduction) in the peripheral speed; or, finally, deformation by longitudinal stretching (elongation) of the tape, followed by a weakening (reduction) of the traction force and a return to its original unstressed state.

British Patent No. 563,638 describes a web densifier which aims to improve on the prior art by using an endless elastic band supported and guided by rollers, one of which rotates at a variable speed greater than the previous roller.

Thus, the part of the belt contained between said two rollers goes into an elongated state, while in the next section, in which there is no tension, the belt undergoes a longitudinal compression equal to the previous elongation. The web, attached to the tape in its elongated part, follows it in the subsequent unstressed part, being partially wound around a rotating and heated cylinder and also undergoing a corresponding longitudinal compression or shrinkage.

However, this technology is not without drawbacks, the first of which is that the elastic band rotates between the guide rollers in a completely natural, unstressed state. Therefore, in the tension release section that follows the section to which a longitudinal traction force is applied causing it to elongate, the belt returns completely to its natural relaxed state without maintaining any minimum residual tension that allows it to move and effectively guide the web in during the shrinkage stage and does not even provide for any control of its own trajectory along its guide rollers.

A further negative aspect is that the elastic band, which is thus designed to increase in length and which is subjected to a longitudinal traction force, also deforms in the transverse direction with a subsequent and uncontrolled reduction in width. When the tensile stress is released, both dimensions of the belt tend to regain their original values, in other words, the belt expands again and since, as mentioned above, it does not maintain any minimum residual tension, its surface tends to flow freely without overstretching, transmitting such inhomogeneity of the canvas attached to it.

The technical solution proposed in European patent application EP1657340A1 partially overcomes the disadvantages described above.

More specifically, this solution provides for a pre-tensile tension applied to the elastic band in such a way that it maintains a minimum residual tension at the end of the pull release stage which causes it to elongate.

More specifically, the web sealing device described in EP1657340A1 comprises a heated rotating cylinder around which an elastic band is partially wound. The elastic band is moved by a plurality of motorized rollers and back-up rollers according to a predetermined closed path.

The roller device is designed in such a way that, by operating in the relative position of one of the rollers, it is possible - during the installation of the belt on the rollers - to pretension said belt with respect to its relaxed state. During operation of the device with respect to this basic pretensioning state, the elastic band is further elongated by stretching before coming into contact with the cylinder. When the tape comes into contact with the web in the winding section on the cylinder, the tape is freely compressed in the longitudinal direction and as a result, drags the web along with it in its movement with respect to the cylinder. The web is thus carried along by the longitudinal compressive movement of the elastic band and as a result is compressed in the longitudinal direction.

The sealing device described above makes it possible to improve the sealing process by pretensioning the belt, but nevertheless the results obtained are not entirely satisfactory.

The holder of the present patent application may note, in particular, that the seal of the textile substrate is disturbed by the stresses induced in the tape in a non-uniform manner as a result of direct contact between the tape and the heated cylinder.

More specifically, in the sealing device, the area of contact (direct or indirect) between the hot cylinder and the elastic band is a highly unstable area because in this area, the elastic deformability features of the band correspond to the hardness of the steel surface of the hot cylinder.

As already mentioned, in this region of the sealing device, the elastic band exerts its sealing action on the textile substrate, imparting to the substrate its own contraction and return movement to the original length (in the pretension state).

In this region of the device, the elastic band slides over the surface of the hot cylinder because the band and the hot cylinder, despite their movement in the same direction, can never have the same speed.

As such, it should be noted that the effect of contraction of the elastic band due to the release of tension produces an apparent negative velocity, resulting in the effect of slowing the band down with respect to the hot cylinder.

This effect amplifies the deceleration of the belt caused by the frictional forces created by the direct contact between the belt and the cylinder.

More specifically, the heated cylinder and the elastic band are sized such that their height is greater than the height of the textile substrates that are typically densified. Thus, during use, it is inevitable that the elastic band comes into direct contact with the heated cylinder in two areas perpendicular to the textile substrate, which slides in the space between the elastic band and the cylinder.

In these two side sections, due to the high coefficient of friction between the material of the elastic band and the metal of the cylinder, sliding and friction occur, which prevent the release of stresses of the tape, and as a result, a local increase in temperature occurs. This localized braking effect produced on the side sections also tends to deform the belt in a different way than in the central section, in which, on the contrary, the elastic tape does not come into direct contact with the side surface of the heated cylinder due to the presence of the textile substrate to be treated. In the central region, the textile substrate essentially slides directly over the cylinder due to the low coefficient of friction.

Such localized deformations create tension on the entire tape and disrupt its shrinkage. This adversely affects the compaction of the treated textile substrate, which

- 2 039952 thus loses its effectiveness.

In addition, non-uniform sliding of the tape produces waves in the direction of stretching said tape in height. These waves, which in addition to the mechanical tension of the tape, reduce its service life, are transmitted to the treated textile substrate, causing it to undesirably fold and stress.

Finally, over time, thermal stresses caused by sliding and friction contribute to premature wear of the elastic band with a subsequent reduction in its service life.

Thus, the holder of the present patent application has found that the phenomena described above adversely affect the efficiency of the sealing process.

Therefore, the purpose of the present invention is to solve the problems associated with these phenomena and to fulfill the general requirements in this field, that is, to make the sealing of the textile substrate more efficient and, possibly, also to increase the service life of the elastic tape.

Brief summary of the present invention

Thus, the object of the present invention is to eliminate, in whole or in part, the disadvantages of the prior art documents cited above by providing a device for compacting textile substrates by means of an elastic band, which allows the tension of the elastic band to be more precisely controlled in such a way as to make the process of compacting the textile more efficient. web substrate and increase the life of the elastic tape.

A further object of the present invention is to provide a device for sealing webs by means of an elastic band, which makes it possible to reduce the stresses imparted to the elastic band during the compression step in contact with a heated cylinder.

A further object of the present invention is to provide a device for sealing webs with an elastic band, the production of which is simple and economical.

A further object of the present invention is to provide a device for sealing webs with an elastic band, which can be operated in an easy-to-operate manner.

Brief description of the figures

The technical features of the present invention according to the above objects can be clearly seen in the content of the following claims, and its advantages will become more apparent from the following detailed description given with reference to the accompanying figures, which illustrate one or more exclusively exemplary and non-limiting embodiments of its implementation, and:

in fig. 1 is a schematic side view of a device for sealing textile substrates with an elastic band according to a first embodiment of the present invention;

in fig. 2 is an enlarged view of part of the diagram of FIG. 1 with respect to the densification zone of the textile substrate, in which the elastic band partially wraps the heated cylinder;

in fig. 3 is a top perspective view of a portion of the sealing device illustrated in FIG. 2;

in fig. 4 is an orthogonal side view of the part of the sealing device illustrated in FIG. 2 in the direction of the arrow IV drawn thereon;

in fig. 5 is a schematic side view of an apparatus for sealing textile substrates with an elastic band according to an alternative embodiment of the present invention;

in fig. 6 is an enlarged view of part of the diagram of FIG. 5 with respect to the densification zone of the textile substrate, in which the elastic band partially wraps the heated cylinder;

in fig. 7 is a top perspective view of a portion of the sealing device illustrated in FIG. 6;

in fig. 8 is an orthogonal side view of a portion of the sealing device illustrated in FIG. 6 in the direction of the arrow VIII drawn thereon.

Detailed disclosure of the present invention

As shown in the accompanying figures, reference number 1 denotes in general a device for sealing a continuous textile substrate with an elastic band according to the present invention.

Advantageously, the textile support T may be of any type; in particular, it may be a woven (shuttle) fabric or a knitted fabric. The textile backing can be made from any type of fiber used for shuttle and knitted fabrics.

- 3 039952

As schematically illustrated in FIG. 1 and 4, the sealing device 1 comprises:

heated rotating cylinder 10;

an endless belt 20 which is elastically deformable upon elongation and also movable along a closed path to support and bring the textile substrate T into contact with a side surface part 10a of said heated rotating cylinder 10;

a system of rollers 31, 32, 33, 34, 35, on which the tape 20 is wound in a state of pretension during elongation.

In turn, such a system of rollers contains a plurality of supporting return rollers 33, 34, 35 and a plurality of motorized rollers 31, 32.

The motorized rollers 31, 32 can be operated so as to cause the belt 20 to slide along said closed path, giving the belt a state of additional tension when elongated with respect to the pretension of the belt in the first section T1 of said path, which runs, with respect to the direction X of the belt movement. , upstream of the second section T2 of such a path in which said tape 20 is held in contact with the rotating cylinder.

The sealing device 1 further comprises a means 40 for guiding the textile substrate T between the belt 20 and the heated cylinder 10 along the second section T2 of such a closed path.

During operation, the sealing action on the textile substrate T takes place along said second section T2 of the closed path. In such a second section T2, the elastic band is elastically compressed from a state of additional elongation tension, which was given to the tape upstream in the first section T1, to a state close to a pretension state. The textile substrate T, which in the second section T2 moves integrally with the web 20 under the action of friction forces, undergoes compression of said web and, in turn, is compressed in the longitudinal direction and thereby compacted.

As illustrated in the accompanying figures, the sealing device 1 includes a system for reducing the coefficient of friction between the belt 20 and the heated rotating cylinder 10.

This friction-reducing system in turn comprises one or more intermediate strips 61, 62 or 63, which are guided into a partially wound state on the cylinder 10 and into direct contact with its side surface 10a to be between the belt 20 and the cylinder side surface 10a. 10 along the above second section T2 of the closed belt path.

The placement of one or more such intermediate strips 61, 62 or 63 between the tape and the cylinder occurs at least on two axial end sections 11, 12 of the side surface 10a of the cylinder 10, which occupy axially opposite positions with respect to the axis of rotation Y of the specified cylinder.

One or more of said intermediate strips 61, 62, or 63 are made of a material that is suitable for creating a lower coefficient of friction with the side surface of the cylinder 10 than the coefficient of friction created with the belt 20.

Thus, in use, the friction reducing system is located on at least two axial end portions of the lateral surface 10a of the cylinder 10, which are generally left uncovered by the treated textile substrate T during use.

In other words, the friction reducing system is configured to prevent direct contact between the elastic band 20 and the side surface 10a of the cylinder 10.

The operation of the present invention utilizes physical phenomena related to friction between various materials, including elastic band material, intermediate strip material, and heated cylinder metal.

Friction forces arise between the elastic band and the textile material, which exceed the friction forces that occur between the textile material and the metal surface of the heated cylinder.

Preferably, the intermediate strips are made of a material that produces the lowest possible frictional forces with the metal surface of the cylinder.

It appears that one or more of said intermediate strips tend to move with the elastic band and follow its compression movements, while one or more of said strips tend to slide freely on the metal surface of the cylinder. Thus, the intermediate strips act as a kind of solid lubricant.

Thus, on the specified axial end sections of the cylinder, due to the placement of one or more of the specified strips between the tape and the cylinder, the conditions are practically recreated

- 4 039952 operation, similar to the conditions that find application in the central area occupied by the processed textile substrate T, which is located between the tape and the cylinder.

This creates a homogeneous friction-reducing system between the belt and the cylinder, which produces the following beneficial effects:

reduction of heat generation on the elastic band;

reduction of mechanical stresses on the elastic tape produced by localized tensions due to different sliding speeds of various parts of the specified tape on the cylinder;

reducing the phenomenon of violation of the movements of compression/shrinkage of the elastic band.

Therefore, thanks to the present invention, the authors provide:

increase in the duration of the operation of the elastic tape; and improving the efficiency of the compaction process.

A further advantage over prior art solutions is that the heated cylinder 10 no longer requires a special expensive surface treatment to reduce the coefficient of friction with the belt 20, but the conventional surface treatment is sufficient to obtain a roughness compatible with the material of the intermediate strips in in order to provide a reduced coefficient of friction. This can be achieved by economical surface coatings, such as nitriding, chromium plating, deep/hard chromium plating.

Preferably, the side surface 10a of the cylinder 10 has a roughness Ra of 10 to 40 microns.

In other words, in contrast to prior art solutions, the roughness of the side surface 10a of the cylinder 10 is no longer the main parameter, since there is no longer direct contact between the belt 10 and the cylinder 20.

Advantageously, because one or more of said intermediate strips slide without friction on the side surface of the cylinder, still being integral with the elastic band, they are practically not affected by either significant slip phenomena or significant overheating phenomena. Thus, these strips have a long service life. This results in a reduction in the required ongoing maintenance.

Preferably, one or more of said intermediate strips 61, 62 or 63 are made from a web or non-woven web.

Thus, the intermediate strips have mechanical characteristics comparable to those of the textile substrates T, which are processed using the sealing device 1.

In particular, the choice of web or nonwoven web makes the intermediate strips more capable of following the compression movements of the tape 20 due to the inherent deformability properties. In this way, the risk that the intermediate strips may interfere with the movements of the belt 20 is reduced.

According to a first embodiment, one or more said intermediate strips can be made from a web containing natural textile fibers, preferably selected from the group consisting of cotton, wool, cellulose.

In an alternative embodiment, one or more of said intermediate strips are made from a web or non-woven web containing synthetic fibers, preferably selected from the group consisting of polyester and nylon.

One or more of said intermediate strips may be made from a blended web containing natural fibers and synthetic fibers.

According to a particularly preferred embodiment, said web or nonwoven web contains elastomeric fibers. Preferably, one or more said intermediate strips are made from a web which is a mixture of polyester and elastane and/or nylon and elastane fibres.

Preferably, said web or said nonwoven web has a basis weight of at least 50 g/m ² . In fact, it has been found that there is an improvement in the effects in terms of increasing the sealing effect compared with the use of canvases or non-woven fabrics, in which the basis weight is less than 50 g/m ² .

According to an embodiment not shown in the accompanying figures, the sealing device 1 comprises a means for wetting with an aqueous solution, preferably only water, one or more of said intermediate strips 61, 62 or 63.

Preferably, wetting of the intermediate strips is provided in the case in which such strips are made of a woven fabric or a non-woven fabric. It has been found that the wetting of the strips facilitates their sliding over the surface of the cylinder and has beneficial effects on the compaction process of the treated textile substrate T.

According to the preferred embodiment illustrated in FIG. 5-8, said friction reducing system comprises two separate intermediate strips 61,

62.

As can be seen in particular in FIG. 7 and 8, said two separate strips 61 and 62 are guided into a state of partial winding on the cylinder 10 and in direct contact with its side surface to be between the tape 20 and the side surface 10a of the cylinder 10 along the above second section T2 of the closed tape path.

More specifically, the first intermediate strip 61 is directed to the first axial end section 11 of the side surface 10a of the cylinder 10, and the second intermediate strip 62 is directed to the second axial end section 12 of the side surface 10a of the cylinder 10.

These two intermediate strips 61, 62 leave an uncovered central portion 13 of the side surface 10a of the cylinder 10 in order to allow the treated textile substrate T to slide in direct contact with the cylinder 10 during use.

Preferably, the position of the axial winding of both or at least one of said two intermediate strips 61, 62 on the cylinder 10 can be adjusted in such a way as to change the amount in the axial direction (along the height) of the uncovered central portion 13.

This adjustment of the axial position is carried out depending on the height H of the textile substrate T to be treated.

Preferably, since the sealing device 1 can be used to process textile substrates T having different heights H, during the design phase, the dimensions of the intermediate strips are determined in relation to the heights H1 and H ₂ at the level of the maximum hypothetical value according to the minimum height H _min that can be textile backing.

More specifically, the two strips 61 and 62 should have a total combined height H1 + H2 such that they cover the two end portions 11 and 12 when the device 1 processes the textile substrate with a minimum height H _min . In other words, if the axial extent of the tape 10 is equal to H _n (it can be the same or less than the axial extent of the cylinder H _c ), the value of (H1 + H ₂ + H _min ) must be the same or greater than H _n .

In other words, the heights H1 and H2 of the two strips 61 and 62 must be determined in such a way that the two end sections 11 and 12 left uncovered by the textile backing T can always be covered by the two intermediate strips 61 and 62.

During operation, it is assumed that the intermediate strips 61 and 62 may protrude in the axial direction with respect to the tape 20 or to the cylinder 10.

According to an alternative embodiment illustrated in FIG. 1-4, said friction reducing system may comprise a single intermediate strip 63 which is directed to be partially wound on the cylinder 10 and in direct contact with its side surface 10a to be positioned between the tape 20 and the side surface of the cylinder 10 throughout said second closed section T2. tape trajectory.

As can be seen in particular in FIG. 3 and 4, said single intermediate strip 63 has an axial extent H3 at least equal to the axial extent H _n of said tape 20.

Thus, during operation, said single intermediate strip 63 is also located between the textile substrate T to be treated and the side surface 10a of the cylinder 10.

In this case, the textile substrate T to be treated does not come into contact with the cylinder 10, but with the intermediate strip 63.

Due to the friction that occurs between the textile substrate T and the intermediate strip 63 (in particular when it is made of a woven fabric or non-woven fabric), the intermediate strip 63 will tend to follow the textile substrate T, forming an integral whole with it, and slide freely with respect to the surface of the cylinder 10. Thus, there will be no sliding between the textile substrate T and the intermediate strip 63. As a result, the textile substrate T will not be affected by the intermediate strip and can thus follow the compression movements of the belt 20, which is favorable for the correct implementation of the compaction process.

Compared to the case of two separate intermediate strips 61 and 62, the use of a single strip 63 eliminates the need to adjust the winding position on the cylinder 10.

However, the embodiment with two separate adjustable strips 61 and 62 is preferable because this results in strip 20 having little or no thickness inhomogeneity when wound around cylinder 10. On the other hand, in the case of a single strip 63 at the side edges of the textile substrate T, the strip 20 experiences a reduction in thickness that may be affected.

Preferably, as illustrated in the accompanying figures, each of one or more of these intermediate strips 61, 62 and 63 forms an endless tape that is wound around a cylinder 10 and a guide system containing one or more return rollers.

71, 72.

Preferably, both of the two separate intermediate strips 61, 62 are guided by the same guide system.

Advantageously, the friction reducing system described above is applicable to any elastic band sealing device that provides pretension to said band.

Preferably, as illustrated in the accompanying figures, the friction reducing system of the present invention is applied to a sealing device as described below.

The above-described system of rollers, on which the tape 20 is wound in a state of pre-tension during elongation, comprises:

motorized drive roller 31;

motorized brake roller 32;

the first supporting return roller 33, which is between the motorized brake roller 31 and the motorized brake roller 32; and a second supporting return roller 34.

Consider the direction X of movement of the belt 20 along a closed path, where the motorized drive roller 31 is the roller immediately upstream of the heated cylinder 10, while the second back-up return roller 34 is the roller immediately downstream of the heated cylinder. ten.

The first section T1 of this closed path (in which the belt 20 elastically elongates during operation, entering into a state of additional tension when elongated with respect to the pre-tension state) passes between the motorized brake roller 32 and the motorized drive roller 31, partially winding around the first supporting return roller 33.

The second section T2 of the path (in which the belt 20 is compressed during operation, leaving the state of additional tension during elongation and returning to the state of pre-tension) passes between the motorized drive roller 31 and the second support return roller 34.

The closed path described above is completed by a third path section T3 extending between the second support return roller 34 and the motorized brake roller 32. pretension state.

The term closed path corresponds to the full extent of the belt 20 when it is installed in a state of pretension on the roller system. The closed trajectory is not affected by local compressions and local elongations of the tape.

Due to this particular configuration of the roller system, the path section other than the compression section in contact with the cylinder is provided in a closed path where the belt can gradually return to the pre-tension state without going into the additional elongation state.

On the other hand, according to the solutions of the prior art, in which the belt is pre-tensioned, with respect to the belt tension state, but with a different configuration of the roller system, the closed belt path is divided into only two sections:

a first extension section where the belt extends from a brake roller immediately downstream of the heated cylinder to a drive roller immediately upstream of the heated cylinder; and a second compression section where the tape passes from the drive roller to the retard roller, being partially wound around a heated cylinder.

Thus, according to the prior art, the tape is continuously stressed in the elongation or compression state, without actually being able to remain in the pre-tension state, which is the state of minimum elongation and which can be considered as the state of rest. As such, immediately downstream of the retard roller, the belt begins to experience a tensile force produced by the drive roller.

On the other hand, according to the present invention, said third section T3 enters a closed path in which the belt, after being compressed in the second section T2, can remain in a pretension state. In other words, the third section T3 can be considered as a resting section for the belt, in contrast to the first extension section T1 and the second compression section T2.

This has a number of advantages:

the effect of the tensile tension exerted on the belt is concentrated on the short section of the path (which is equal to the tension of the closed path and the second section T2); thus, by influencing the speeds of the motorized drive and brake rollers, it is possible to more precisely control the elongation imparted to the belt, with subsequent improved control of the sealing effect on the textile substrate;

the tape experiences less mechanical stress, because after the implementation of its compression, it can reach a state of rest and remain in it in a certain section; reducing the voltage acting on the tape, allows you to increase the duration of the specified tape.

These advantages are enhanced by the use of the friction reducing system according to the present invention.

Preferably, the motorized drive rollers 31 and brake rollers 32 supporting the return rollers 33, 34, 35 and also the heated cylinder 10 are made of metal, preferably steel.

According to a particularly preferred embodiment of the present invention, as illustrated in the accompanying figures, both the motorized brake roller 32 and the motorized drive roller 31 are provided with a rubber coating 36 which is applied to respective cylindrical side surfaces intended to be in contact with the belt 20.

By means of the rubber coating 36 of the motorized rollers, the coefficient of friction between the motorized rollers and the belt is increased compared to the case of the belt being in contact with an uncoated cylinder surface, which is typically smooth metal.

During operation, an increase in the coefficient of friction reduces the risk of slipping between the belt and the rollers. This contributes to better control of the tensile action of the belt and thus to an increase in the efficiency of the densification process of the textile substrate.

Preferably, unlike the two motorized rollers 31 and 32, both the first return support roller 33 and the second return support roller 34 are not rubber coated. In other words, both the first back-up return roller 33 and the second back-up return roller 34 have a cylindrical side surface, preferably made of a metallic material, and designed to come into direct contact with the belt 20 without an intermediate rubber coating applied to such a cylindrical side surface.

In use, since the back-up return rollers 33 and 34 are not coated with rubber and the elastic band 20 comes into direct contact with their metal side surface, the friction between the belt and the back-up rollers is reduced. Thus, by reducing friction, the belt encounters fewer obstacles during its elastic expansion and subsequent contraction.

In operation, a state of additional elongation tension is imparted to the belt 20 by influencing the speeds of the motorized drive roller 31 and the motorized brake roller 32 so as to create a difference between the tangential speeds of the side surfaces of the two rollers (intended to contact the belt). The degree of tension at elongation (measured, for example, by percentage elongation with respect to the pre-tension state) increases as the difference between said speeds decreases.

Advantageously, the device 1 may comprise a control unit 50, preferably electronic, adapted to regulate the rotation of the motorized drive roller 31 and the motorized brake roller 32 so that said two motorized rollers 31, 32 rotate in the same direction, and as a result, the tangential speed Vt of the motorized drive roller 31 is more than the tangential speed Vf of the motorized brake roller 32 according to the predetermined ratio Vf/Vt.

Advantageously, such a predetermined ratio Vf/Vt between the tangential speed of the motorized brake roller 32 and the tangential speed of the motorized drive roller 31 can be adjusted depending on the amount of additional longitudinal elongation imparted to the belt in the first section of the path T1.

Preferably said target ratio Vf/Vt is 0.5 to 0.9 and preferably 0.7.

Preferably, the heated rotary cylinder 10 is motorized. The term heated cylinder means in particular a cylinder provided with or connected to a heating device. The heating device may be of any type suitable for the purpose, i. e. to heat the surface of the rotating cylinder.

Preferably, the control unit 50 is configured to control the rotation of the heated cylinder so that its tangential speed (determined by the side surface 10a) is as close as possible to and preferably equal to the tangential speed of the motorized drive roller 31.

It turned out to be possible to verify that under the specified conditions the best results are obtained with regard to the compaction of the textile substrate. In other words, under these conditions, increases

- 8 039952 efficiency of the compaction process.

Preferably, the motorized drive roller 31, the motorized brake roller 32, and the first return roller 33 are positioned relative to each other such that the aforementioned first closed path section T1 has a length that does not exceed 35% of the entire closed path, and is preferably not less than ten%.

Advantageously, as schematically represented in FIG. 1, the motorized drive roller 31, the motorized brake roller 32, and the first return support roller 33 are positioned relative to each other so as to assume a compact configuration. The term compact configuration means a configuration in which said three rollers 31, 32 and 33 are in close proximity to each other compared to the other rollers 34 and 35 of the roller system.

The compact configuration is mainly intended to reduce as much as possible the stretching of the first path section T1 in favor of the third path section T3.

In particular, said three rollers 31, 32 and 33 can be arranged to form a three roller system with aligned centers of rotation. Such a variant is preferable from a structural point of view, since it allows for a reduction in overall dimensions and simplifies the support structure of said rollers. However, three-roller system configurations may be proposed in which the rollers are not aligned with each other.

Preferably, the motorized drive roller 31, the motorized brake roller 32, and the first back-up roller 33 are positioned relative to each other such that the winding angle of said tape 20 on the motorized drive roller 31 and the motorized brake roller 32 is not less than 90°.

In particular, as shown schematically in FIG. 1, the belt is mounted on a system of three rollers in such a way as to pass in an S-shaped path between the three rollers. In particular, two motorized rollers 31 and 32 come into contact with the belt on its inner surface, while the first back-up roller 33 comes into contact with the belt on its outer surface. Thus, the first supporting return roller 33 located between the two motorized rollers 31 and 32 can push the tape towards them, which is favorable for winding the tape. !The pushing action of the return roller and thus the effect on winding conditions can be calibrated by changing the nominal diameters of the rollers and/or the relative position of the centers of rotation.

In operation, the greater the angle of winding the tape on the drive roller 31 and the brake roller 32, the greater the friction that is generated between the motorized rollers and the belt, and thus the more effective the traction effect of the rollers on the belt with the reduction of slip phenomena between the roller. and tape.

This contributes to better control of the stretching action on the belt and thus to an increase in the efficiency of the densification process of the textile substrate.

As already mentioned above, consider the direction X of movement of the belt 20 along a closed path, where the motorized drive roller 31 is the roller immediately upstream of the heated cylinder 10, while the second return support roller 34 is the roller immediately below. downstream relative to the heated cylinder 10.

Preferably, the motorized drive roller 31 and the second return roller 34 are positioned relative to the cylinder 10 such that:

the distance D1 between the side surface 31a of the motorized drive roller 31 and the side surface 10a of the cylinder 10 is the same as or less than the thickness S of the belt 20; and the distance D2 between the side surface 10a of the cylinder 10 and the side surface 34a of the second supporting return roller 34 is the same as or greater than the thickness S of the belt 20.

Preferably, the above distance D1 is less than the thickness S of the tape 20 by about 0 to about 50%; wherein said distance D2 is greater than the thickness S of the tape 20 by an amount from about 0 to about 100%.

Preferably, said second back-up return roller 34 is movable relative to the other rollers 31, 32, 33 to change their relative position and allows:

installation and removal of the tape on the specified system of rollers;

tape maintenance operations; and pre-tensioning the belt 20.

According to a particularly preferred embodiment shown in FIG. 1, the second supporting return roller 34 is movable with respect to the other rollers 31, 32, 33 along an arc of a circle concentric with respect to the axis of rotation of the cylinder 10 between the position of the maximum winding of the tape on the cylinder and the position of the minimum winding.

- 9 039952 per cylinder.

For this purpose, the second supporting return roller 34 forms a sliding connection at both of its axial ends with a guide (not shown in the accompanying figures), the shape of which corresponds to the indicated circular arc.

Preferably, the second back-up return roller 34 is designed to be locked both in said two limit positions of said circular arc and in one or more intermediate positions, so as to regulate the stretching of said second section T2 of the closed path and, consequently, the degree of winding of the tape on the cylinder. 10. In this way it is possible to calibrate the sealing effect on the textile substrate according to the requirements determined by the type of fiber and the result to be obtained. In this way, it is also possible to improve and reduce the friction effect of the tape on the hot cylinder, in exact proportion to the decrease in the winding angle. This is favorable for the result of the compaction process.

Fixation of the second supporting return roller 34 along the above-shaped guide can be carried out by means of consoles, which also contain bearings suitable for the rotating pin of the roller, and which can be attached, for example, by screws, to the supporting structure of the device. In particular, the attachment of the roller takes place on protrusions suitably perforated in advance along said guide at predetermined angular positions corresponding to the adjustable positions to be obtained.

Preferably, as shown in FIG. 1, the circular arc has a magnitude of 90°. Arcs of a circle of smaller size can be provided according to technological requirements.

Adjusting the position of the second supporting return roller 34 with respect to the cylinder 10 changes the tension state of the belt.

Preferably, as illustrated in FIG. 1, the device 1 includes a third back-up roller 35 which comes into contact with the belt in the third section T3 of the path and is movable with respect to the other rollers 31, 32, 33 to compensate for position changes of the second back-up roller 34.

Similar to that provided for the second return support roller 34, the third return return support roller 35 also forms a sliding connection at both of its axial ends with a guide (not shown in the accompanying figures) which is suitably shaped. The third support roller 35 can also be fixed and stopped also in intermediate positions between the two positions of maximum and minimum compensation. Fixation can be carried out by means of consoles which contain roller bearings and which will be attached with screws on the protrusions of the device, suitably perforated in the given positions.

Preferably, similarly to the first and second return rollers 33 and 34, the third return roller 35 is also rubber-free. In other words, the third back-up roller 35 also has a cylindrical side surface, preferably made of a metallic material, designed to come into direct contact with the belt 20 without an intermediate rubber coating applied to such a cylindrical side surface.

In use, as already mentioned with respect to the return support rollers 33 and 34, also for the third return support roller 35, due to the lack of rubber coating and thus the fact that the elastic band 20 comes into direct contact with the metal side surface such a third support roller 35, the friction between the belt and the support roller is reduced. Thus, by reducing friction, the belt encounters fewer obstacles in the course of its sliding, which prevents localized stresses due to friction.

Preferably, the aforementioned belt 20 is configured to elastically deform at a percentage elongation of 5 to 100% of its unstressed length before pretension, and preferably in its pretension state at a percentage elongation of 30 to 50% of its length at relaxed state.

Preferably, the tape 20 has a thickness S of about 4.0 mm to about 16.0 mm, and preferably about 10 mm.

The tape 20 may be made from an elastic material having significant extensibility, and in particular from natural or synthetic rubber, or combinations thereof. Advantageously, the material may contain additives suitable for improving its mechanical properties and thermal stability.

The present invention achieves several advantages, some of which have already been described.

- 10 039952

The device for sealing textile substrates with an elastic band according to the present invention makes it possible to make the sealing of the textile substrate more efficient and increase the service life of the elastic band by reducing the frictional forces between the tape and the cylinder.

The device for sealing textile substrates with an elastic band according to the present invention makes it possible to reduce the stresses acting on the elastic band during its use, and in particular in the compression zone on the heated cylinder.

The apparatus for sealing textile substrates with an elastic band according to the present invention is simple and economical to manufacture.

The device for sealing textile substrates with an elastic band according to the present invention can be operated in a technologically simple manner.

The device for compacting textile substrates by means of an elastic band according to the present invention makes it possible, in particular, due to the particular configuration of the roller system, to adjust the tension of the elastic band more precisely, so as to make the web compaction process more efficient.

The apparatus for sealing textile substrates with an elastic band according to the present invention makes it possible to reduce the stresses imparted to the elastic band during use as a whole, and not only in the compression zone.

Additional benefits achieved with the sealing device according to the present invention are listed below:

high accuracy of tape stretching, elongation due to the use of rubber rollers;

guarantee of perfect drive without slipping of the tape on the drive and brake rollers due to the wide winding angle on these rollers (this is provided by the intermediate supporting roller);

high process speed, high productivity;

high compaction efficiency, high degree of compaction for all blades;

no need to repeatedly pass the same web through the device to obtain the required degree of compaction (implementation of the process in one stage);

the possibility of processing both woven (shuttle) and knitted fabrics;

the possibility of processing fibers of all types used for shuttle and knitted fabrics;

excellent compaction results at high speed even with viscose fiber webs;

excellent compaction results at high speed even with cotton and denim-like fabrics.

Of course, according to a practical embodiment, the device can also take on forms and configurations that differ from those described above, without departing from the scope of the patent protection of the present invention.

In addition, all parts can be replaced with technically equivalent elements, and the dimensions, shapes and materials used can be any according to needs.

Claims (25)

1. A device for sealing a continuous textile substrate (T) with an elastic band, comprising: heated rotating cylinder (10); an endless belt (20) configured to move along a closed path (P) to support and bring the textile substrate (T) into contact with a part (11) of the side surface of said heated rotating cylinder (10), said belt being elastically deformable when elongated; a system of rollers (31, 32, 33, 34, 35), on which the specified tape (20) is wound in a state of pre-tension during elongation, and the specified system of rollers contains a plurality of supporting return rollers (33, 34, 35) and a plurality of motorized rollers ( 31, 32) made in such a way as to make the specified tape (20) slide along the specified closed path (P), bringing the specified tape into a state of additional tension when elongated in the first section (T1) of the specified trajectory passing, with respect to the direction ( X) the movement of the tape, upstream relative to the second section (T2) of the specified trajectory, in which the specified tape (20) is maintained in contact with the rotating cylinder; a device (40) for guiding said textile substrate (T) between said tape (20) and said heated cylinder (10) along said second section (T2) of said path, the device comprising a system for reducing the coefficient of friction between tape (20) and heated rotating cylinder (10), and the specified system for reducing the coefficient - 11 039952 friction contains one or more intermediate strips (61, 62; 63), which: are directed to the state of partial winding on the specified cylinder (10) and in direct contact with its side surface (10a) to be between the specified tape (20) and the side surface (10a) of the specified cylinder (10) throughout the specified second section (T2) a closed path of the tape on at least two axial end sections (11, 12) of the side surface of the specified cylinder (10), which are in axially opposite positions with respect to the axis of rotation (Y) of the specified cylinder; and made of a material that is suitable for creating with the side surface of the cylinder (10) a lower coefficient of friction than the coefficient of friction created with the tape (20), characterized in that said system for reducing the coefficient of friction contains two separate intermediate strips (61, 62), which are directed to the state of partial winding on the specified cylinder (10) and in direct contact with its side surface to be between the specified tape (20) and the side surface of the specified cylinder (10) along the specified second section (T2) of the closed trajectory tape, and in which the first intermediate strip (61) is directed to the first axial end section (11) of the side surface (10a) of the specified cylinder (10) and the second intermediate strip (62) is directed to the second axial end section (12) of the side surface (10a ) of said cylinder (10), wherein said two intermediate strips (61, 62) leave an uncovered central part current (13) of the side surface (10a) of the cylinder (10) to allow the treated textile substrate (T) to slide in direct contact with the cylinder (10) during use. 2. Device according to claim 1, in which the position of axial winding of both or at least one of said intermediate strips (61, 62) on said cylinder (10) is adjustable so as to change the value in the axial direction of said uncovered central plot (13). 3. The device according to claim 1, in which each of the two said intermediate strips forms an endless tape, which is wound on the specified cylinder and on the guide system containing one or more return rollers (71, 72). 4. The device according to claim 1, in which each of the two said intermediate strips forms an endless tape, which is wound on the specified cylinder and on the guide system containing one or more return rollers (71, 72), and in which both of the two separate intermediate strips (61, 62) are guided by one guide system. 5. Device according to claim 1, wherein both of said intermediate strips are made from a web or non-woven web. 6. Device according to claim 1, wherein both said intermediate strips are made from a web containing natural textile fibers, preferably selected from the group consisting of cotton, wool, cellulose. 7. Device according to claim 1, wherein both said intermediate strips are made from a web or non-woven web containing synthetic fibers, preferably selected from the group consisting of polyester and nylon. 8. Device according to claim 1, wherein both said intermediate strips are made from a blended web containing natural fibers and synthetic fibers. 9. The apparatus of claim 5, wherein said web or said nonwoven web comprises elastomeric fibers. 10. The apparatus of claim 5, wherein said web or said nonwoven web has a basis weight of at least 50 g/m ² . 11. The apparatus of claim 1, wherein said roller system comprises a motorized drive roller (31), a motorized brake roller (32), a first back-up roller (33) that is between said motorized drive roller and said motorized brake roller, and the second supporting return roller (34), and at the same time the first section (T1) of the specified trajectory passes between the specified motorized brake roller (32) and the specified motorized drive roller (31), partially winding on the specified first supporting return roller (33), while while said second section (T2) of the path passes between said motorized drive roller (31) and said second supporting return roller (34), wherein said closed path is completed by a third section (T3) passing between said second supporting return roller (34) and specified motorized brake roller (32), and at the same time during operation on the tension of the specified third section (T3) of the trajectory, the specified tape (20) is in a state of relaxed tension with respect to the first section (T1) of the trajectory. 12. The device according to claim 11, in which both the specified motorized brake roller (32) and the specified motorized drive roller (31) are provided with a rubber coating applied to the respective cylindrical side surfaces intended to come into contact with the specified - 12 039952 with tape (20). 13. Apparatus according to claim 12, wherein said first back-up roller (33) is provided with a cylindrical side surface made of metallic material and intended to come into direct contact with said belt (20). 14. Apparatus according to claim 11, wherein said second supporting return roller (34) is provided with a cylindrical side surface made of metallic material and intended to come into direct contact with said belt (20). 15. Apparatus according to claim 11, wherein said motorized drive roller (31), said motorized brake roller (32) and said first supporting return roller (33) are positioned relative to each other such that said first section (T1) of the closed path has a length whose value does not exceed 35% of the entire closed path and preferably is not less than 10%. 16. Apparatus according to claim 11, wherein said motorized drive roller (31), said motorized brake roller (32) and said first back-up roller (33) are positioned relative to each other such that the winding angle of said tape (20 ) to said motorized drive roller (31) and to said motorized brake roller (32) is at least 90°. 17. Device according to claim 11, comprising a control unit (50) configured to control the rotation of said motorized drive roller (31) and said motorized brake roller (32) so that said two motorized rollers (31, 32) rotate in the same direction, and in such a way that the tangential speed (Vt) of said motorized drive roller (31) is more than the tangential speed (Vf) of said motorized brake roller (32) according to a predetermined ratio (Vf/Vt). 18. Apparatus according to claim 17, wherein said predetermined ratio (Vf/Vt) between the tangential speed of said motorized brake roller (32) and the tangential speed of said motorized drive roller (31) is adjusted depending on the degree of longitudinal elongation to which said belt is subjected in said first section (T1) of said path. 19. An apparatus according to claim 18, wherein said predetermined ratio (Vf/Vt) is between 0.5 and 0.9 and preferably is 0.7. 20. Device according to claim 1, wherein the heated cylinder (10) is motorized. 21. The device according to claim 17, in which the heated cylinder (10) is motorized and in which the specified control unit (50) is configured to control the rotation of the specified heated cylinder (10) in such a way that its tangential velocity, determined by its side surface (10a), preferably equal to the tangential speed of the motorized drive roller (31). 22. The device according to claim 11, in which the specified second support return roller (34) is movable in relation to other rollers (31, 32, 33) to change its relative position and provide assembly and pre-tensioning of the specified tape (20) on the specified roller system. 23. Device according to claim 11, wherein said second supporting return roller (34) is movable with respect to the other rollers (31, 32, 33) along an arc of a circle concentric with respect to the axis of rotation of the cylinder (10) between the position the maximum winding of the tape on the specified cylinder and the position of the minimum winding on the specified cylinder, and is also made with the possibility of fixing in one or more intermediate positions between the specified two positions to control the stretching of the specified second section (T2) of the closed trajectory, and the specified device (1) contains the third supporting return roller (35), which comes into contact with the specified tape in the specified third section (T3) of the trajectory and is movable in relation to other rollers (31, 32, 33) to compensate for changes in the position of the specified second support return roller ( 34) and thus maintaining the pretension of said belt. 24. Apparatus according to claim 23, wherein said second supporting return roller (34) is provided with a cylindrical side surface made of metallic material and intended to come into direct contact with said belt (20). 25. The device according to claim 1, containing a device for wetting with an aqueous solution, preferably only water, one or more of these intermediate strips (61, 62; 63).