Device for compacting a continuous textile substrate by means of an elastic band

Abstract

The invention relates to an apparatus for compacting a continuous textile substrate by means of an elastic belt, comprising: a heatable rotating drum; an endless belt, which is movable along a closed path to support and transport the textile substrate in contact with a portion of the side surface of the drum, the belt being elastically deformable in elongation; a roller system on which the belt is wound in a pre-tensioned state in elongation, the roller system comprising a plurality of idle bearing rollers and a plurality of motorized rollers, which can be operated to slide the belt along the closed path, applying an additional elongated tension on the belt in a first section of the path, the first section extending upstream of a second section of the path with respect to the direction of advancement of the belt, the belt being in contact with the drum in the second section; means for guiding the textile substrate between the belt and the drum along the second section of the path. The apparatus comprises a system for reducing the coefficient of friction between the belt and the drum, the system comprising one or more interposed strips between the belt and the drum.

Description

Technical Field

[0001] The invention relates to a device for compacting a continuous textile substrate (greige fabric) by means of an elastic band. Background Art

[0002] It is well known that the compaction process of fabric or textile substrate is one of the main processes in the field of textile finishing and aims to give stability to the fabric before proceeding to the manufacturing steps.

[0003] Usually, the stability and compaction of the fabric are imparted by machines using integrated technology, using a variation in the curvature of a felt or rubber belt on which the fabric to be imparted with compaction is placed. The variation in the curvature of the support (felt or rubber belt) then imparts a longitudinal retraction to the fabric, which is then pressed against hot rollers, which stabilizes the compaction effect, thus ensuring dimensional stability of the fabric once it leaves the machine.

[0004] All fabrics, whether orthogonal or knitted, require a stabilization and compaction process after production to make them suitable for cutting for sewing. Therefore, compaction machines are widely used in finishing processes. The compaction value that can be obtained depends on the initial degree of stability of the fabric produced. The initial degree of stability of the fabric, in turn, depends on the type of material it is made of.

[0005] Often, the same fabric must be passed through the compactor several times in order to achieve the desired compaction effect. This is especially true if the fabric has a high degree of instability to begin with. All this prolongs the processing time and affects production costs.

[0006] Therefore, there is a great need in the art to reduce the time of the fabric compaction process, especially in the case of fabrics characterized by a high degree of initial instability, such as those made of viscose fibers.

[0007] Over time, different alternative technical solutions have been proposed which aim to make compaction systems more efficient. However, these solutions have proven to be not entirely satisfactory.

[0008] In more detail, the compaction (or tightening) process of the fabric is essentially carried out by means of the so-called "compression" technique, which is based on the use of a substantially deformable belt to which the fabric to be compacted is tightly coupled. The deformation of the belt in the longitudinal direction of advance - by means of mechanical means suitable for this purpose - consists essentially of a succession of a first stretching step and a second contraction step. The fabric, which is integrally engaged with the deformable surface of the belt, undergoes a "compression" in the direction of advance, ie a compaction of its structure and ultimately a longitudinal contraction, in particular during the contraction step.

[0009] The deformability of the belt can be determined by the type and characteristics of the material from which it is made, and also by the type of mechanical stress applied to it by mechanical means suitable for deforming the belt. Thus, deformation of the belt is known by pressing, which causes its extension (elongation), followed by its contraction (shortening) to an initial relaxed state; or by a variation of the peripheral speed of the belt, obtained by sliding the belt on rollers or drums with different radii of curvature in alternating concave and convex paths, which causes an alternating increase (lengthening) and decrease (shortening) of the peripheral speed; or, finally, by a longitudinal traction (elongation) of the belt, followed by a release of the traction (shortening) to an initial relaxed state.

[0010] GB patent 563 638 describes a device for compacting fabrics which aims to improve the prior art by using an endless elastic belt supported and guided by rollers, one of which rotates at a variable speed and faster than the one preceding it. In this way, the portion of the belt comprised between the two rollers is placed in a state of extension, while in the following section, as the tension is relaxed, the belt undergoes a longitudinal contraction equal to the previous extension.

[0011] The fabric coupled to the belt at its elongated portion follows the belt in a subsequent slack portion, partially winding around a rotating and heated drum, also undergoing a corresponding longitudinal contraction or tightening.

[0012] However, this technique is not without drawbacks, the first of which relates to the fact that the elastic band rotates between the guide rollers in a completely and naturally relaxed state. Thus, in the tension release section following the section in which the longitudinal traction causing the band to elongate is applied, the band returns completely to its natural relaxed state, without maintaining any minimal residual tension that would allow it to transport and effectively guide the fabric during the tightening step, and without even providing any control over the path of the band itself around its guide rollers.

[0013] A further disadvantage is related to the fact that an elastic band subjected to longitudinal traction - and therefore extensible in length - also deforms transversely, causing a consequent and uncontrolled reduction in width. When the tensile stress ceases, both dimensions of the band tend to recover their original size, that is to say, the band widens again, and since, as mentioned, the band does not maintain any minimum residual tension, its surface tends to flow loosely and not be taut, transmitting such irregularities to the fabric coupled thereto.

[0014] The technical solution proposed in European patent application EP1657340A1 overcomes the above-mentioned disadvantages.

[0015] In more detail, this solution provides for a pre-tensioning traction to be applied to the elastic band such that the elastic band retains a minimum residual tension at the end of the release step of the traction, which causes the elastic band to elongate.

[0016] In more detail, the fabric compacting device described in EP1657340A1 comprises a heated rotating drum around which an elastic band is partially wound. The elastic band is moved according to a predefined closed path by a plurality of motorized rollers and idle support rollers.

[0017] The roller device is configured so that, by manipulating the relative position of one of the rollers, the belt itself can be pre-tensioned relative to its relaxed state during assembly on the roller. During operation of the device, the elastic belt is further tightened by elongation before coming into contact with the roller relative to this basic pre-tensioned state. When the belt comes into contact with the fabric in the winding section around the roller, the belt is free to contract in the longitudinal direction, thereby dragging the fabric in a relative movement relative to the roller. In this way, the fabric is pulled by the longitudinal contraction movement of the elastic belt and is therefore compacted in the longitudinal direction.

[0018] The compacting device described above allows improving the compacting process by means of belt pretensioning, but the results obtained are not entirely satisfactory. The owner of the present patent application has been able to note that, in particular, the compaction of the textile substrate is disturbed by the tensioning caused in a non-uniform manner on the belt by the direct contact between the belt and the heated roller.

[0019] In more detail, in a compacting device, the contact area (direct or indirect) between the heated roller and the elastic belt is a highly unstable area, since the elastically deformable nature of the belt meets the rigidity of the steel surface of the heated roller.

[0020] As already mentioned, in this region of the compacting device the elastic band exerts its compacting action on the textile substrate, which is transmitted as a contraction of the substrate itself and then moves back to the original (pre-tensioned) length.

[0021] In this area of ​​the device, the elastic belt slides on the surface of the heated roller, since the belt and the heated roller - although moving in the same direction - never have the same speed.

[0022] In fact, it should be noted that the shortening effect of the elastic belt due to the release of tension generates a significant negative speed, resulting in a deceleration effect of the belt relative to the hot roller.

[0023] This effect exacerbates the belt deceleration caused by the friction generated by the direct contact between the belt and the drum.

[0024] In more detail, the heated roller and the elastic band are dimensioned so that their height is greater than the height of the textile substrate that is usually subjected to compaction. It is therefore inevitable that during use the elastic band comes into direct contact with the heated roller at two strips that are positioned transversely with respect to the sliding textile substrate inserted between the elastic band and the roller.

[0025] At these two side strips, due to the high coefficient of friction between the material of the elastic band and the metal of the drum, sliding and friction occur that oppose the relaxation of the band, thus locally increasing the temperature. This local braking effect on the side strips also tends to deform the band differently from the central strip, where, on the contrary, the elastic band is not in direct contact with the lateral surface of the heated drum due to the presence of the textile substrate being treated. In fact, in the central strip, the elastic band slides directly on the drum by means of a low coefficient of friction.

[0026] This local deformation creates tension throughout the belt and interferes with the tightening of the belt. This adversely affects the compaction of the textile substrate being processed, with a consequent loss of efficiency.

[0027] Furthermore, the non-uniform sliding of the belt generates undulations extending along the height of the belt itself. These undulations, besides mechanically straining the belt and reducing its operational life, are also transmitted to the textile substrate being processed, causing undesirable wrinkles and tensions in the textile substrate.

[0028] Ultimately, over time, thermal stresses caused by sliding and friction cause the elastic belt to wear prematurely, ultimately reducing the operational life of the elastic belt.

[0029] Thus, the owner of the present patent application has discovered that the phenomenon described above negatively affects the efficiency of the compaction process.

[0030] The present invention therefore aims to solve the problems associated with these phenomena and to meet the general need in the art, namely to make the compaction of textile substrates more efficient and also to increase the operational life of elastic bands. Summary of the invention

[0031] Therefore, the object of the present invention is to completely or partially eliminate the disadvantages of the prior art stated above by providing a device for compacting a textile substrate with the aid of an elastic band, which device allows the compaction process of the textile substrate to be more efficient and the operating life of the elastic band to be increased.

[0032] A further object of the invention is to provide a device for compacting a fabric by means of an elastic band which allows reducing the stress exerted on the elastic band in contact with the heatable roller during the shrinking step.

[0033] A further object of the invention is to provide a device for compacting fabrics by means of elastic bands which is simple and cost-effective to manufacture.

[0034] A further object of the invention is to provide a device for compacting fabrics by means of elastic bands which can be managed in an operationally simple manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The technical features of the present invention according to the above-mentioned purpose can be clearly seen in the content of the attached claims, and its advantages will become more easily understood in the following detailed description with reference to the accompanying drawings, which illustrate one or more merely exemplary and non-limiting embodiments of the present invention, wherein:

[0036] Figure 1 shows a schematic side view of an apparatus for compacting a textile substrate by means of an elastic band according to a first embodiment of the invention;

[0037] Figure 2 Shows Figure 1 , an enlarged view of a detail relating to a compacted area of ​​a textile substrate in which an elastic band is partially wrapped around a heated drum;

[0038] Figure 3 shows the compaction equipment Figure 2 A three-dimensional top view of the portion illustrated in FIG.

[0039] Figure 4 shows the compaction equipment Figure 2 An orthogonal side view of a portion according to arrow IV shown therein illustrated in FIG.

[0040] Figure 5 shows a schematic side view of an apparatus for compacting a textile substrate by means of an elastic band according to an alternative embodiment of the present invention;

[0041] Figure 6 Shows Figure 5 , an enlarged view of a detail relating to a compacted area of ​​a textile substrate in which an elastic band is locally wrapped around a heated roller;

[0042] Figure 7 Shows Figure 6 A perspective top view of a portion of the compacting apparatus illustrated in FIG.

[0043] Figure 8 shows the compaction equipment Figure 6 An orthogonal side view of the portion according to arrow VIII shown therein is illustrated in FIG. DETAILED DESCRIPTION

[0044] With reference to the accompanying drawings, reference numeral 1 denotes as a whole an apparatus for compacting a continuous textile substrate by means of an elastic band according to the present invention.

[0045] Advantageously, the textile substrate T may be of any type; in particular, it may be an orthogonal (woven) fabric or a knitted fabric.The textile substrate may be formed of any type of fibers used for woven and knitted fabrics.

[0046] As in Figure 1 and Figure 4 As schematically illustrated in FIG. 1 , the compacting device 1 comprises:

[0047] - a heatable rotating drum 10;

[0048] - an endless belt 20 which is elastically deformable in terms of elongation and which is movable along a closed path to support and convey the textile substrate T in contact with the side surface portion 10a of the heatable rotating drum 10;

[0049] A roller system 31 , 32 , 33 , 34 , 35 , on which the belt 20 is wound in an extended pretensioned state.

[0050] This roller system in turn comprises a plurality of idle support rollers 33 , 34 , 35 and a plurality of motorized rollers 31 , 32 .

[0051] The motorized rollers 31, 32 are operable to slide the belt 20 along the aforementioned closed path, exerting on it an additional state of elongation tension relative to the pre-tensioned state in a first section T1 of said path, this first section extending upstream of a second section T2 of such a path with respect to the direction of advancement X of the belt, in which said belt 20 remains in contact with the rotating drum.

[0052] The compacting device 1 further comprises means 40 for guiding the textile substrate T between the belt 20 and the heatable cylinder 10 along a second section T2 of such a closed path.

[0053] In operation, along the above-mentioned second section T2 of the closed path, a compaction effect is performed on the textile substrate T. At such a second section T2, the elastic band elastically contracts, changing from the additional elongated tension state applied to the band in the upstream first section T1 to a state close to pre-tension. The textile substrate T in the second section T2 moves integrally with the band 20 due to friction, undergoes the contraction of the band itself and then contracts in the longitudinal direction to compact itself.

[0054] As illustrated in the figures, the compacting device 1 comprises a system for reducing the coefficient of friction between the belt 20 and the heatable rotating drum 10 .

[0055] This friction reduction system in turn comprises one or more insertion strips 61, 62 or 63 which are guided to be partially wound around the drum 10 and in direct contact with the side surface 10a of the drum so as to insert itself / themselves between the belt 20 and the side surface 10a of the drum 10 along the aforementioned second section T2 of the closed path of the belt.

[0056] This insertion of one or more insertion strips 61, 62 or 63 between the belt and the drum takes place at at least two axial end strips 11, 12 of the side surface 10a of the drum 10, which are in axially opposite positions relative to the rotation axis Y of the drum itself.

[0057] The one or more inserted strips 61 , 62 or 63 are made of a material suitable for generating a coefficient of friction with the side surface of the drum 10 that is lower than the coefficient of friction generated with the belt 20 .

[0058] In operation, the friction coefficient reduction system is therefore inserted at least at the two axial end strips of the lateral surface 10a of the drum 10 which, in use, are usually not covered by the textile substrate T being treated.

[0059] In other words, the friction coefficient reducing system is configured to avoid direct contact between the elastic belt 20 and the side surface 10 a of the drum 10 .

[0060] In operation, the present invention utilizes the physical phenomena associated with the friction between the following dissimilar materials: the elastic belt material; the inserted strip material; and the metal of the heatable roller.

[0061] A friction force is generated between the elastic band and the textile material, which friction force is greater than the friction force generated between the textile material and the metal surface of the heatable cylinder.

[0062] Preferably, the insert strip is made of a material that generates the least possible friction with the metal surface of the drum.

[0063] This follows from the aforementioned one or more inserted strips tending to move integrally with the elastic band and following the contraction of the elastic band, while the one or more strips tending to slide freely on the metal surface of the drum. Thus, the inserted strips act as a solid lubricant.

[0064] In this way, at the aforementioned axial end strips of the drum, due to the one or more strips inserted between the belt and the drum, operating conditions similar to those used in the central strip occupied by the textile substrate T being processed inserted between the belt and the drum are essentially reproduced.

[0065] This creates a uniform friction reduction system between the belt and the pulley, which has beneficial effects in terms of:

[0066] - Reduced heat generation on the elastic band;

[0067] - Reduction of the mechanical stresses on the elastic band generated by local tensions due to the different sliding speeds of different parts of the band itself on the rollers;

[0068] - Reduces the disturbing phenomenon of the elastic band's shrinking / tightening movement.

[0069] Therefore, thanks to the present invention, we:

[0070] - Increased operating life of the elastic band; and

[0071] - Improved efficiency of the compaction process.

[0072] Another advantage over the prior art solutions lies in the fact that the heatable roller 10 no longer requires a special and expensive surface treatment to reduce the friction coefficient with the belt 20, but a conventional surface treatment is sufficient to obtain a roughness compatible with the material of the inserted strip to obtain a reduced friction coefficient. This can be achieved with a low-cost surface coating, which is obtained, for example, by nitriding, chrome plating, deep / intensive chrome plating.

[0073] Preferably, the side surface 10a of the drum 10 has a roughness Ra between 10 micrometers and 40 micrometers.

[0074] In other words, unlike prior art solutions, the roughness of the lateral surface 10a of the drum 10 is no longer an essential parameter, since direct contact between the belt 10 and the drum 20 is no longer provided.

[0075] Advantageously, due to the fact that the one or more inserted strips slide frictionlessly on the side surface of the drum, remaining integral with the elastic band, they are substantially no longer subject to significant sliding phenomena, nor to significant overheating phenomena. The operating life of these strips is therefore high. This results in reduced operating maintenance requirements.

[0076] Preferably, the one or more insert strips 61, 62 or 63 are made of woven or non-woven fabric.

[0077] In this way, the inserted strip has mechanical properties comparable to those of the textile substrate T treated by the compacting device 1 .

[0078] In particular, the choice of woven or nonwoven fabric, due to its intrinsic deformable nature, makes the inserted strip more able to follow the contraction movement of the belt 20. Thus, the risk that the inserted strip may interfere with the movement of the belt 20 is reduced.

[0079] According to a first embodiment, the one or more inserted strips may be made of a fabric of natural textile fibers, preferably selected from the group consisting of cotton, wool, cellulose.

[0080] According to an alternative embodiment, the one or more inserted strips are made of a woven or nonwoven fabric of synthetic fibers, preferably selected from the group consisting of polyester and nylon.

[0081] The one or more inserted strips may be made from a mixed fabric of natural and synthetic fibers.

[0082] According to a particularly preferred embodiment, the aforementioned woven or nonwoven fabric comprises elastic fibers. Preferably, the aforementioned one or more inserted strips are made of a fabric defined by a mixture of polyester elastic fibers and / or nylon elastic fibers.

[0083] Preferably, the fabric or nonwoven fabric has a basis weight of not less than 50 g / m2. In fact, it has been found that this has an improved effect on increasing compaction efficiency compared to using a fabric or nonwoven fabric with a weight of less than 50 g / m2.

[0084] According to an embodiment not shown in the figures, the compacting device 1 comprises means for wetting the one or more inserted strips 61 , 62 or 63 with an aqueous solution, preferably only with water.

[0085] Preferably, in the case where such strips are made of woven fabric or nonwoven fabric, wetting of the inserted strips is provided. It has been found that wetting of the strips promotes their sliding on the surface of the drum and has a beneficial effect on the compaction process of the textile substrate T to be treated.

[0086] according to Figures 5 to 8 In the preferred embodiment illustrated in FIG. 6 , the aforementioned friction coefficient reduction system comprises two different inserted strips 61 , 62 .

[0087] As in particular Figure 7 and Figure 8 As can be seen in FIG. 1 , the two different strips 61 and 62 are guided to be partially wound around the drum 10 and in direct contact with the side surface of the drum to insert themselves between the belt 20 and the side surface of the drum 10 along the aforementioned second section T2 of the closed path of the belt.

[0088] In more detail, the first insertion strip 61 is guided at a first axial end strip 11 of the lateral surface 10 a of the drum 10 , and the second insertion 62 is guided at a second axial end strip 12 of the lateral surface 10 a of the drum 10 .

[0089] The two inserted strips 61 , 62 leave the central strip 13 of the lateral surface 10 a of the drum 10 uncovered, so as to allow the textile substrate T to be treated to slide in direct contact with the drum 10 , in use.

[0090] Preferably, the axial winding position of two or at least one of the two inserted strips 61, 62 around the drum 10 is adjustable so as to change the width (height) of the uncovered central strip portion 13 in the axial direction.

[0091] This adjustment of the axial position is carried out as a function of the height H of the textile substrate T to be treated.

[0092] Preferably, since the compacting device 1 may have to handle textile substrates T having different heights H, during the design step the dimensions of the inserted strips are set according to the heights H1 and H2 with a maximum assumed value according to the minimum height Hmin that the textile substrate may have.

[0093] In more detail, the two strips 61 and 62 should have an overall height H1+H2 for covering the two end strips 11 and 12, in order to provide for the apparatus 1 to process a textile substrate having a minimum height Hmin. In other words, if the axial extension of the belt 10 is equal to Hn (which may be equal to or less than the axial extension of the drum Hc), then (H1+H2+Hmin) should be equal to or greater than Hn.

[0094] In other words, the heights H1 and H2 of the two strips 61 and 62 should be sized so that the two end strips 11 and 12 not covered by the textile substrate T can always be covered by the two inserted strips 61 and 62 .

[0095] Operationally, it is allowed that the insertion strips 61 and 62 can protrude axially with respect to the belt 20 or with respect to the drum 10 .

[0096] according to Figures 1 to 4 In an alternative embodiment illustrated in the figure, the aforementioned friction coefficient reduction system may include a single insertion strip 63, which is guided to be locally wrapped around the roller 10 and directly contact the side surface 10a of the roller for inserting itself between the belt and the side surface of the roller 10 along the second section T2 of the closed path of the belt 20.

[0097] As in particular Figure 3 and Figure 4 As can be seen in FIG. 6 , the single inserted strip 63 has an axial extension H3 that is at least equal to the axial extension Hn of the belt 20 .

[0098] Thus, in use, the single insertion strip 63 is also inserted between the textile substrate T to be treated and the side surface 10a of the drum 10 .

[0099] In this case, the textile substrate T to be treated does not come into contact with the drum 10 but with the inserted strip 63 .

[0100] Due to the friction formed between the textile substrate T and the inserted strip 63 (especially when the inserted strip is made of a woven fabric or a non-woven fabric), the inserted strip 63 will tend to follow the textile substrate T integrally and slide freely relative to the surface of the drum 10. Therefore, there will be no slip between the textile substrate T and the inserted strip 63. The textile substrate T will therefore not be disturbed by the inserted strip, and can therefore follow the contraction movement of the belt 20 to facilitate the correct execution of the compaction process.

[0101] The use of a single strap 63 as opposed to two different inserted straps 61 and 62 avoids the need to adjust the winding position around the drum 10 .

[0102] However, the embodiment with two different strips 61 and 62 whose positions can be adjusted is preferred, since in this way the strip 20 encounters substantially no thickness discontinuities in its winding around the drum 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 encounters a thickness reduction which could interfere with it.

[0103] Advantageously, as illustrated in the accompanying figures, each of the one or more inserted strips 61 , 62 or 63 forms an endless belt wound around the drum 10 and a guide system comprising one or more support rollers 71 , 72 .

[0104] Preferably, both of the two different insertion strips 61 , 62 are guided by the same guiding system.

[0105] Advantageously, the friction reducing system described above may be applied in any compacting apparatus having an elastic belt that provides pre-tensioning of the belt itself.

[0106] Preferably, the friction reducing system according to the invention is applied to a compacting device as described below, as illustrated in the accompanying drawings.

[0107] The above-mentioned roller system, on which the belt 20 is wound in a pre-tensioned state in terms of elongation, comprises:

[0108] - Motorized drive roller 31;

[0109] - Motorized brake roller 32;

[0110] a first idle bearing roller 33 arranged between the motorized drive roller 31 and the motorized brake roller 32 ; and

[0111] - A second idle support roller 34 .

[0112] With reference to the direction of advancement X of the belt 20 along the closed path, the motorized drive roller 31 is the roller placed immediately upstream of the heatable roller 10 , whereas the second idle bearing roller 34 is the roller placed immediately downstream of the heatable roller 10 .

[0113] The aforementioned first section T1 of the closed path (where the belt 20 is elastically stretched in use, receiving an additional stretched tension relative to the pre-tensioned state) extends between the motorized brake roller 32 and the motorized drive roller 31, passing through the first idle support roller 33 in a manner partially wound around it.

[0114] A second section T2 of the path, where the belt 20 itself contracts in use, losing the additional elongated tension to return to the pre-tensioned state, extends between the motorized drive roller 31 and the second idle support roller 34 .

[0115] The above closed path is completed by a third section T3 of the path extending between the second idle bearing roller 34 and the motorized brake roller 32. In use, along such third section T3 of the path, the belt 20 is in a tensioned state relaxed relative to the first section T1 of the path, substantially corresponding to a pre-tensioned state.

[0116] The "closed path" corresponds to the total extension of the belt 20 when mounted on the roller system with pretensioning. The closed path is not affected by local contractions and local extensions of the belt.

[0117] Due to this particular configuration of the roller system, a path section different from the contraction path section in contact with the drum is provided in the closed path, in which provided path section the belt is free to gradually return to the pretensioned state without being subjected to an additional elongation state.

[0118] On the other hand, in the prior art solutions providing pre-tensioning of the belt, but with a different roller system configuration, the closed path of the belt is divided into only two sections with respect to the tensioned state of the belt:

[0119] a first “elongated” section extending from a brake roller arranged immediately downstream of the heatable roller to a drive roller arranged upstream of the heatable roller; and

[0120] - A second "constriction" section, which extends from the driving roller to the braking roller, partially wraps around the heatable cylinder.

[0121] Therefore, according to the prior art, the belt is continuously stressed in an elongated or contracted manner, without actually being kept in a pre-tensioned state, i.e. in a state of minimum elongation that can be considered a rest state. In fact, the belt immediately downstream of the brake roller already begins to experience the elongation exerted by the drive roller.

[0122] On the contrary, due to the aforementioned configuration of the roller system, the aforementioned third section T3 has been introduced into the closed path, in which third section the belt is free to remain in a pre-tensioned state after having been contracted in the second section T2. ​​In other words, the third section T3 can be considered as a rest section of the belt, in contrast to the first section of extension T1 and the second section of contraction T2.

[0123] This has many advantages:

[0124] - the tensioning elongation effect exerted on the belt is concentrated on a shorter section of the path (equal to the extension of the closed path and the second section T2); in this way, by acting on the speed of the motorized drive roller and the brake roller, it is possible to more accurately control the elongation exerted on the belt and thus better control the compaction of the textile substrate;

[0125] - The belt is subject to less mechanical stress, since it is free to reach a resting state after having shrunk and remain so for certain sections; the reduced stress on the belt allows the useful life of the belt itself to be extended.

[0126] These advantages are enhanced by employing the friction reduction system according to the invention.

[0127] Preferably, the motorized drive roller 31 and the brake roller 32, the idle support rollers 33, 34, 35 and the heatable cylinder 10 are made of metal, preferably steel.

[0128] According to a particularly preferred embodiment of the invention, as illustrated in the accompanying drawings, both the motorized braking roller 32 and the motorized driving roller 31 are provided with a rubber coating 36 covering the respective cylindrical side surfaces intended to come into contact with the belt 20 .

[0129] Due to the rubber coating 36 of the motorized roller, the coefficient of friction between the motorized roller and the belt is increased relative to the situation where the belt is in contact with the bare surface of the roller, usually smooth metal.

[0130] Operationally, the increase in the coefficient of friction reduces the risk of slippage between the belt and the roller. This helps to improve the control of the elongation effect of the belt and therefore helps to increase the efficiency of the compaction process of the textile substrate.

[0131] Preferably, both the first idle support roller 33 and the second idle support roller 34 are not coated with rubber, unlike the two motorized rollers 31 and 32. In other words, both the first idle support roller 33 and the second idle support roller 34 are provided with a cylindrical side surface, preferably made of metal material, intended to come into direct contact with the belt 20 without the interposition of a rubber coating covering such cylindrical side surface.

[0132] In operation, since the idle support rollers 33 and 34 are not rubber coated and the elastic belt 20 is in direct contact with the metal side surfaces of the aforementioned idle support rollers, the friction between the belt and the idle rollers is reduced. Thus, due to the reduced friction, the belt encounters less resistance in its elastic extension and subsequent contraction.

[0133] In operation, by acting on 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), an additional elongation tension is imposed on the belt 20. As the difference in these speeds increases, the elongation tension (measurable, for example, by a percentage of elongation relative to the pre-tensioning state) increases.

[0134] Advantageously, the device 1 may comprise a control unit 50, preferably electronic, configured to control the rotation of the motorized drive roller 31 and the motorized brake roller 32 so that the two motorized rollers 31, 32 rotate in the same direction and so that the tangential speed Vt of the motorized drive roller 31 is higher than the tangential speed Vf of the motorized brake roller 32 according to a predefined ratio Vf / Vt.

[0135] Advantageously, this predefined ratio Vf / Vt between the tangential speed of the motorized braking roller 32 and the tangential speed of the motorized driving roller 31 is adjustable according to the degree of additional longitudinal extension to be applied to the belt at the first section T1 of the path.

[0136] Preferably, said predefined ratio Vf / Vt is between 0.5 and 0.9, and is preferably equal to 0.7.

[0137] Preferably, the heatable rotating drum 10 is motorized. "Heatable drum" means in particular a drum provided with or associated with heating means. The heating means may be of any type suitable for the purpose, ie heating the surface of a rotating drum.

[0138] Advantageously, the control unit 50 is configured to control the rotation of the heatable drum such that its tangential speed (with respect to the side surface 10 a ) is as close as possible to and preferably equal to the tangential speed of the motorized drive roller 31 .

[0139] It can be verified that under these conditions, the best results are obtained with regard to the compaction of the textile substrate. In other words, under these conditions, the efficiency of the compaction process is increased.

[0140] Preferably, the motorized drive roller 31 , the motorized brake roller 32 and the first idle support roller 33 are positioned relative to each other so that the above-mentioned first section T of the closed path has a length extending not more than 35% of the entire closed path and preferably not less than 10% of the entire closed path.

[0141] Advantageously, as in Figure 1 As schematically shown in FIG, the motorized drive roller 31, the motorized brake roller 32 and the first idle support roller 33 are positioned relative to each other so that a compact configuration is adopted. A compact configuration means a configuration in which the three rollers 31, 32 and 33 are close to each other when compared to the other rollers 34 and 35 of the roller system.

[0142] The “compact configuration” essentially aims at minimizing the extension of the first section T1 of the path, in favor of the third section T3 of the path.

[0143] In particular, the three rollers 31, 32 and 33 can be arranged to form a triplet roller with aligned centers of rotation. This option is preferred from a construction point of view, since it allows to reduce the overall dimensions and simplifies the support structure of the rollers themselves. However, a construction of a triplet roller can be provided in which the rollers are not aligned with each other.

[0144] Preferably, the motorized drive roller 31 , the motorized brake roller 32 and the first idle support roller 33 are positioned relative to one another so that the wrapping angle of the belt 20 around the motorized drive roller 31 and the motorized brake roller 32 is not less than 90°.

[0145] In particular, as in Figure 1 , the belt is mounted on a triplet of rollers so as to follow an S-shaped path between the three rollers. In particular, the two motorized rollers 31 and 32 contact the belt on its inner surface, while the first idle bearing roller 33 contacts the belt on its outer surface. The first idle bearing roller 33 inserted between the two motorized rollers 31 and 32 can thus push the belt against the two motorized rollers to facilitate the winding of the belt. The "pushing" action of the bearing rollers and therefore the effect in terms of winding can be calibrated by operating on the nominal diameter of the rollers and / or on the relative position of the center of rotation.

[0146] In operation, the greater the winding angle of the belt on the drive roller 31 and the brake roller 32, the greater the friction generated between the motorized rollers and the belt, and therefore the more effective the dragging action of the rollers on the belt, which reduces the slip phenomenon between the rollers and the belt.

[0147] This helps to improve the control of the elongation effect of the belt and therefore helps to increase the efficiency of the compaction process of the textile substrate.

[0148] As already described above, with reference to the advancement direction X of the belt 20 along the closed path, the motorized drive roller 31 is the roller placed immediately upstream of the heatable drum 10 , whereas the second idle bearing roller 34 is the roller placed immediately downstream of the heatable drum 10 .

[0149] Preferably, the motorized drive roller 31 and the second idle support roller 34 are positioned relative to the drum 10 such that:

[0150] - the distance D1 between the lateral surface 31a of the motorized drive roller 31 and the lateral surface 10a of the drum 10 is equal to or less than the thickness S of the belt 20; and

[0151] The distance D2 between the side surface 10 a of the drum 10 and the side surface 34 a of the second idle support roller 34 is equal to or greater than the thickness S of the belt 20 .

[0152] Preferably, the distance D1 is smaller than the thickness S of the belt 20 by a value between about 0% and about 50%, and the distance D2 is larger than the thickness S of the belt 20 by a value between about 0% and about 100%.

[0153] Advantageously, the aforementioned second idle bearing roller 34 is movable relative to the other rollers 31 , 32 , 33 to vary their relative position and allow:

[0154] - Assembly and disassembly of the belt on said roller system;

[0155] -with maintenance operations; and

[0156] - Pre-tensioning of belt 20.

[0157] according to Figure 1 In a particularly preferred embodiment shown, the second idle bearing roller 34 is movable relative to the other rollers 31 , 32 , 33 along a circumferential arc concentric with the axis of rotation of the drum 10 between a maximum winding position of the belt around the drum and a minimum winding position around the drum.

[0158] For this purpose, the second idle bearing roller 34 is slidably engaged at its two axial ends to guides (not shown in the drawings) which are shaped according to said circumferential arc.

[0159] Advantageously, the second idle support roller 34 can be locked both in the aforementioned two extreme positions of the aforementioned circumferential arc and in one or more intermediate positions in order to adjust the extension of the second section T2 of the closed path and thus the degree to which the belt is wound around the drum 10. In this way, the compaction effect on the textile substrate can be calibrated according to the requirements determined by the fiber type and the result to be obtained. In this way, the friction effect of the belt on the hot drum can also be precisely improved and reduced due to the reduction of the winding angle. This has a beneficial effect on the result of the compaction process.

[0160] The locking of the second idle support roller 34 along the aforementioned shaped guide can be implemented by means of a bracket, which also includes a bearing suitable for rotating the pin of this roller and which can be fixed to the supporting structure of the device, for example by means of a screw. In particular, the fixing of the roller takes place at a shoulder that is suitable for being perforated beforehand, along said guide, in a predefined angular position corresponding to the adjustment position to be provided.

[0161] Preferably, as in Figure 1 As shown in FIG. 1 , the circumferential arc has an extension of 90°. Depending on operational requirements, a circumferential arc with a smaller width can be provided.

[0162] The position adjustment of the second idle support roller 34 relative to the drum 10 changes the tension state of the belt.

[0163] Preferably, as in Figure 1 As illustrated in , the device 1 comprises a third idle bearing roller 35 which engages the belt at the third section T3 of the path and which is movable relative to the other rollers 31 , 32 , 33 to compensate for position variations of the second idle bearing roller 34 .

[0164] The third idle bearing roller 35 can also be slidably engaged at its two axial ends to suitably shaped guides (not shown in the drawings), similar to those provided for the second idle bearing roller 34. The third idle bearing roller 35 can also be fixed and stopped in an intermediate position between the two compensation positions, maximum and minimum. The fixing can be carried out by means of a bracket, which includes roller bearings and is fixed by screwing at a shoulder of the device that is suitably perforated at a predefined position.

[0165] Preferably, the third idle support roller 35 is also not coated with rubber, like the first and second idle support rollers 33 and 34. In other words, the third idle support roller 35 is also provided with a cylindrical side surface, preferably made of a metal material, which is intended to be in direct contact with the belt 20 without the interposition of a rubber coating covering such cylindrical side surface.

[0166] In operation, as already mentioned with respect to the idle bearing rollers 33 and 34, for the third idle bearing roller 35, the friction between the belt and the idle roller is also reduced due to the absence of a rubber coating and therefore the fact that the elastic belt 20 is in direct contact with the metal side surface of such third idle bearing roller 35. In this way, due to the reduction in friction, the belt encounters less resistance in its sliding, avoiding localized tension due to friction.

[0167] Preferably, the belt 20 is elastically deformable in elongation by a percentage between 5% and 100% of its length in a relaxed state before being pre-tensioned, and preferably in its pre-tensioned state, is elastically deformable in elongation by a percentage between 30% and 50% relative to its relaxed length.

[0168] Preferably, the belt 20 has a thickness S comprised between about 4.0 mm and about 16.0 mm, and preferably of about 10 mm.

[0169] The belt 20 may be made of a substantially extensible and elastic material, in particular of natural or synthetic rubber or a combination thereof. Advantageously, the material may contain additives suitable for improving its mechanical and thermal properties.

[0170] The invention allows several advantages to be achieved, some of which have already been described.

[0171] The device according to the invention for compacting a textile substrate by means of an elastic belt allows making the compaction of the textile substrate more effective and increasing the operational life of the elastic belt, due to the reduction of the friction between the belt and the drum.

[0172] The device according to the invention for compacting a textile substrate by means of an elastic band allows reducing the stresses exerted on the elastic band during use, and in particular in the shrinkage zone around a heatable cylinder.

[0173] The device according to the invention for compacting a textile substrate by means of an elastic band is simple to produce and cost-effective.

[0174] The device according to the invention for compacting a textile substrate by means of an elastic band can be managed in an operationally simple manner.

[0175] The device according to the invention for compacting a textile substrate by means of an elastic band allows, in particular due to the specific configuration of the roller system, a more precise control of the tensioning of the elastic band in order to make the textile compacting process more efficient.

[0176] The device according to the invention for compacting a textile substrate by means of an elastic band allows reducing the stress exerted on the elastic band during use as a whole and not only at the contraction zone.

[0177] Listed below are further advantages which can be obtained with the compacting device according to the invention:

[0178] - High precision of belt elongation, thanks to the use of rubber rollers;

[0179] - Perfect drive guaranteed without belt slipping on the drive and brake rollers due to the wide winding angles on the rollers themselves (given by the inserted idler rollers)

[0180] -High processing speed, high productivity

[0181] -High compaction efficiency, high compaction value for all fabrics

[0182] - No need to run the same fabric several times in the machine to obtain the correct compaction value (one-step process)

[0183] -Can process both orthogonal (woven) and knitted fabrics

[0184] -Can process all types of fibers for woven and knitted fabrics

[0185] -Excellent compaction at high speeds, even in the case of viscose fabrics

[0186] -Excellent compaction at high speeds, even on cotton and denim-like fabrics

[0187] Obviously, in its actual implementation, shapes and structures other than the above may also be adopted without departing from the scope of protection.

[0188] Moreover, all the details may be substituted with technically equivalent elements and the dimensions, shapes and materials used may be any according to requirements.

Claims

1. A device for compacting a continuous textile substrate (T) by means of an elastic band, the device comprising: - a heatable rotating drum (10); - an endless belt (20) movable along a closed path (P) to support and convey the textile substrate (T) in contact with the side surface (10a) of the heatable rotating drum (10), the endless belt being elastically deformable in terms of elongation; - a roller system on which the endless belt (20) is wound in an extended pre-tensioned state, wherein the roller system comprises a plurality of idle support rollers and a plurality of motorized rollers, the plurality of motorized rollers being operated to slide the endless belt (20) along the closed path (P), applying an additional extended tensioned state to the endless belt in a first section (T1) of the closed path, the first section of the closed path extending upstream of a second section (T2) of the closed path with respect to the advancement direction (X) of the endless belt, in which the endless belt (20) remains in contact with the heatable rotating drum; - means (40) for guiding the textile substrate (T) along the second section (T2) of the closed path between the endless belt (20) and the heatable rotating drum (10), Characterized in that the device comprises a system for reducing the coefficient of friction between the endless belt (20) and the heatable rotating drum (10), the system for reducing the coefficient of friction comprising at least two inserted strips, - the inserted strip is guided to be partially wound around the heatable rotating drum (10) and to be in direct contact with the side surface (10a) of the heatable rotating drum, so that the inserted strip is inserted between the endless belt (20) and the side surface of the heatable rotating drum (10) along the second section (T2) of the closed path of the endless belt, at least at two axial end strip portions of the side surface (10a) of the heatable rotating drum (10), the two axial end strip portions being axially located at opposite positions with respect to the rotation axis (Y) of the heatable rotating drum; and - the inserted strip is made of a material suitable for generating a smaller coefficient of friction with the side surface of the heatable rotating drum (10) than with the endless belt (20), The insertion strip comprises a first insertion strip (61) and a second insertion strip (62), wherein the first insertion strip (61) is guided to be located at a first axial end strip portion (11) of the side surface (10a) of the heatable rotating drum (10), and the second insertion strip (62) is guided to be located at a second axial end strip portion (12) of the side surface (10a) of the heatable rotating drum (10), and the first insertion strip (61) and the second insertion strip (62) leave a central strip portion (13) of the side surface (10a) of the heatable rotating drum (10) uncovered, so as to allow the textile substrate (T) to be treated to slide in direct contact with the heatable rotating drum (10) during use.

2. The device according to claim 1, wherein: The axial winding position of at least one of the first insertion strip (61) and the second insertion strip (62) around the heatable rotating drum (10) is adjustable so as to change the width of the uncovered central strip portion (13) in the axial direction.

3. The device according to claim 1 or 2, wherein: Each of the first inserted strip (61) and the second inserted strip (62) forms an endless belt wound around the heatable rotating drum and around a guide system comprising one or more support rollers.

4. The device according to claim 3, wherein: Both the first insertion strip (61) and the second insertion strip (62) are guided by the same guiding system.

5. The device according to claim 1, wherein: The first insertion strip (61) and the second insertion strip (62) are made of fabric.

6. The device according to claim 1, wherein: The first insert strip (61) and the second insert strip (62) are made of fabric of natural textile fibers.

7. The device according to claim 6, wherein: The natural textile fibers are selected from the group consisting of cotton and wool.

8. The device according to claim 1, wherein: The first insert strip (61) and the second insert strip (62) are made of synthetic fiber fabric.

9. The device according to claim 8, wherein: The synthetic fibers are selected from the group consisting of polyester and nylon.

10. The device according to claim 1, wherein: The first insert strip (61) and the second insert strip (62) are made of a mixed fabric of natural fibers and synthetic fibers.

11. The device according to claim 5 or 8, wherein: The fabric includes elastic fibers.

12. The device according to claim 5 or 8, wherein: The fabric has a weight of not less than 50 g / m2.

13. The apparatus according to claim 1, wherein: The plurality of motorized rollers include a motorized drive roller (31) and a motorized brake roller (32), the plurality of idle support rollers include a first idle support roller (33) and a second idle support roller (34), the first idle support roller being arranged between the motorized drive roller and the motorized brake roller, And wherein the first section (T1) of the closed path extends between the motorized brake roller (32) and the motorized drive roller (31), passing through the first idle support roller in a manner partially wrapped around the first idle support roller (33), and the second section (T2) of the closed path extends between the motorized drive roller (31) and the second idle support roller (34), wherein the closed path is completed by a third section (T3) extending between the second idle support roller (34) and the motorized brake roller (32), and the endless belt (20) is in a tensioned state along the third section (T3) of the closed path in use, which is relaxed relative to the first section (T1) of the closed path.

14. The device according to claim 13, wherein: Both the motorized braking roller (32) and the motorized driving roller (31) are provided with a rubber coating covering the respective cylindrical side surfaces intended to come into contact with the endless belt (20).

15. The device according to claim 14, wherein: The first idle support roller (33) is provided with a cylindrical side surface made of a metal material, the cylindrical side surface of the first idle support roller being intended to be in direct contact with the endless belt (20) without the interposition of a rubber coating covering the cylindrical side surface.

16. The apparatus according to any one of claims 13 to 15, wherein: The second idle support roller (34) is provided with a cylindrical side surface made of a metal material, the cylindrical side surface of the second idle support roller being intended to be in direct contact with the endless belt (20) without the interposition of a rubber coating covering the cylindrical side surface.

17. The apparatus according to any one of claims 13 to 15, wherein: The motorized drive roller (31), the motorized brake roller (32) and the first idle support roller (33) are positioned relative to each other so that the first section (T1) of the closed path has a length extending no more than 35% of the entire closed path.

18. The apparatus according to any one of claims 13 to 15, wherein: The motorized drive roller (31), the motorized brake roller (32) and the first idle support roller (33) are positioned relative to each other so that the first section (T1) of the closed path has a length extending not less than 10% of the entire closed path.

19. The apparatus according to any one of claims 13 to 15, wherein: The motorized drive roller (31), the motorized brake roller (32) and the first idle support roller (33) are positioned relative to each other so that the winding angle of the endless belt (20) around the motorized drive roller (31) and around the motorized brake roller (32) is not less than 90°.

20. Apparatus according to any one of claims 13 to 15, comprising a control unit (50) configured to control the rotation of the motorised drive roller (31) and the motorised brake roller (32) such that the motorised drive roller (31) and the motorised brake roller (32) rotate in the same direction and such that the tangential speed Vt of the motorised drive roller (31) is higher than the tangential speed Vf of the motorised brake roller (32) according to a predefined ratio Vf / Vt.

21. The apparatus according to claim 20, wherein: The predefined ratio Vf / Vt between the tangential speed of the motorized brake roller (32) and the tangential speed of the motorized drive roller (31) is adjustable according to the degree of longitudinal extension to be applied to the endless belt at the first section (T1) of the closed path.

22. The apparatus according to claim 21, wherein The predefined ratio Vf / Vt is between 0.5 and 0.

9.

23. The apparatus of claim 21, wherein: The predefined ratio Vf / Vt is equal to 0.

7.

24. The apparatus according to claim 1 or 2, wherein: The heatable rotating drum (10) is motorized.

25. The apparatus of claim 20, wherein: The control unit (50) is configured to control the rotation of the heatable rotating drum (10) so that the tangential speed of the heatable rotating drum with respect to the side surface (10a) of the heatable rotating drum is equal to the tangential speed of the motorized drive roller (31).

26. The apparatus of claim 13, wherein: The second idle support roller (34) is movable relative to the other rollers to change the relative position of the second idle support roller and to allow assembly and pretensioning of the endless belt (20) on the roller system.

27. The apparatus of claim 13, wherein: The second idle support roller (34) is movable relative to the other rollers along a circumferential arc concentric with the rotation axis of the heatable rotating drum (10), between a maximum winding position of the endless belt around the heatable rotating drum and a minimum winding position around the heatable rotating drum, and can be locked in one or more intermediate positions between the maximum winding position and the minimum winding position to adjust the extension of the second section (T2) of the closed path, And wherein the device comprises a third idle support roller (35) which engages with the endless belt at the third section (T3) of the closed path and is movable relative to the other rollers to compensate for position changes of the second idle support roller (34) and thereby maintain the pretensioning of the endless belt.

28. The apparatus of claim 27, wherein: The third idle support roller (35) is provided with a cylindrical side surface made of a metal material, the cylindrical side surface of the third idle support roller being intended to be in direct contact with the endless belt (20) without the interposition of a rubber coating covering the cylindrical side surface of the third idle support roller.

29. Apparatus according to claim 1 or 2, comprising means for wetting said first insert strip (61) and said second insert strip (62) with an aqueous solution.

30. Apparatus according to claim 1 or 2, comprising means for wetting said first (61) and said second (62) insert strips only with water.

31. The apparatus of claim 1, wherein: The first insert strip (61) and the second insert strip (62) are made of non-woven fabric.

32. The apparatus of claim 1, wherein: The first insert strip (61) and the second insert strip (62) are made of a nonwoven fabric of synthetic fibers.

33. Apparatus according to claim 31 or 32, wherein: The nonwoven fabric includes elastic fibers.

34. Apparatus according to claim 31 or 32, wherein: The nonwoven fabric has a weight of not less than 50 g / m2.

35. The apparatus of claim 7, wherein: The natural textile fibers include cellulose.

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