Patent Description:
The present invention is applicable to the textile field and, in particular, relates to a shrinking machine for fabrics.

More in detail, the present invention relates to the shrinking portion of a shrinking machine.

During the processing process, a fabric is subjected to a certain tension, which causes its temporary elongation. The need therefore arises to eliminate the aforesaid elongation in order to prevent the fabric from spontaneously recovering it during or after the packaging of the final product. In fact, this aspect irremediably compromises the quality of the product itself.

To this end, fabric shrinking machines are known to induce recovery of elongation and stabilize the fabric after processing.

Among such known machines we can distinguish shrinking machines comprising a felt belt arranged in a closed loop around a series of rollers which manage, among other things, its movement.

In particular, there are an inlet roller and an outlet roller, arranged in contact with the inner side of the loop, and an intermediate cylinder interposed between the aforementioned rollers and of considerably greater diameter than these, arranged in contact with the outer side of the loop so as to create a concavity in the latter.

The fabric to be treated is made to pass between the belt and the intermediate cylinder. There is also a flexible sheet, generally of Teflon-coated glass fibre, called "shoe", arranged between the inlet roller and the intermediate cylinder so as to keep the fabric in contact with the belt on a trajectory stretch that develops around the inlet roller upstream of the intermediate cylinder.

The aforesaid flexible sheet has the advantage of easily adapting to variations in thickness of the fabric, such as those at the seams, while maintaining the fabric adhering to the belt.

The inlet roller, the intermediate cylinder and the flexible sheet define a trajectory for the fabric which comprises a first stretch with a concavity facing the inlet roller and an immediately following stretch with a concavity facing the intermediate cylinder, i.e. opposed to that of the previous stretch. Advancing along the aforementioned trajectory, the fabric is kept in contact with the surface of the felt belt and undergoes the same surface deformations of the latter.

More precisely, during the passage between the inlet roller and the intermediate cylinder, the felt belt reverses its curvature so as to shrink its outer surface. The aforementioned compression is transmitted to the fabric and causes its shrinking.

The intermediate cylinder is heated, generally by means of steam injected into a cavity of the cylinder itself, so as to heat the fabric during shrinking so as to make the latter more effective and durable. Such operation is known as fabric ironing.

Since the greater the difference in speed between the convex trajectory stretch and the concave stretch, the greater the shrinking potential of the machine, in order to try to increase the effect of fabric shrinking, an attempt was made to reduce to a minimum the diameter of the inlet roller and to increase belt thickness. With this last modification, in particular, the shrinking force exerted by the belt on the fabric is increased.

However, even with such adjustments, the outlet fabric tends, over time, to lengthen, thereby partially losing the potential shrinking obtained by affecting the quality of the product.

Since the ironing has an important effect in terms of maintaining the shrinking, the diameter of the intermediate cylinder is also increased to extend the duration of the ironing in order to increase its fixing effect of fabric shrinking.

However, this not only makes it possible to avoid totally non-negligible subsequent elongations, but constitutes an economic damage for the user since the machine has larger dimensions and higher consumption both in terms of mechanical locomotion and in terms of heat developed for ironing.

<CIT>, <CIT> and <CIT> are known and are some examples of the described prior art.

The object of the present invention is to overcome at least partially the drawbacks highlighted above by providing a shrinking machine which improves maintenance of the shrinking of fabrics leaving the treatment.

Another object is that the shrinking machine does not degrade the quality of the outlet fabric.

A further object is that the shrinking machine of the invention is shaped in such a way as not to present the above-mentioned production speed reduction, so as not to pose an economic damage to the user.

Another object is that the shrinking machine of the invention has dimensions as small as possible and low consumption both in mechanical terms and in terms of developed heat, while ensuring a degree of shrinking which lasts longer than the equivalent known machines over time.

Said objects, as well as others which will become clearer below, are achieved by a shrinking machine according to the following claims, which are to be considered as an integral part of this patent.

In particular, the machine comprises at least one flexible belt for supporting and transporting the fabric. This belt is arranged in a closed loop around at least one inlet roller and at least one outlet roller. There is also at least one intermediate body located near the flexible belt between the two inlet and outlet rollers. In this sense, a portion of the outer surface of the intermediate body identifies with a corresponding stretch of the flexible belt a sliding channel for the fabric.

The flexible belt, therefore, during its sliding around the inlet roller, sees at least its outer surface extend. In this situation, it receives the fabric, supporting it. Subsequently, the same flexible belt is subjected to a lower curvature, if not null or inverted, as in the case of the drawings. As a consequence, the same outer surface of the flexible belt is shrunk, which induces an equivalent effect on the fabric. The latter, therefore, is shrunk.

The aforementioned sliding channel allows first of all to keep the fabric arranged in contact with the flexible belt during its shrinking. Furthermore, since the intermediate body is typically heated, in the channel there is a heat transfer to the tissue in order to stabilize its shrinking. In other words, the shrunk fabric is ironed in the channel.

According to an aspect of the invention, the shrinking machine also comprises a limited-area pressure element arranged between the intermediate body and the flexible belt for pressing the fabric in a point of the sliding channel. In particular, this pressure element defines a pressure area having a shorter length of one or more orders of magnitude with respect to the width so as to be comparable to a line and which develops transversely to the feed direction of the fabric a point of said sliding channel.

In other words, advantageously, the limited-area pressure element exerts a pressure on the fabric because it interposes between the intermediate body and the flexible belt. This pressure is substantially punctual, given the previously defined definition of a limited-area pressure element. This pressure is therefore contained in the space, thereby advantageously avoiding having drastic effects on the fabric.

Advantageously, the limited-area pressure element acts where the shrinking effect is maximum and begins to combine with the ironing. In this sense, a sudden and punctual increase in the pressure in such points advantageously obtains significant effects on the stabilization of the shrinking of the fabric emerging from the machine of the invention, since it modifies the shape of the fabric mesh in the most important moment of the treatment. The fact that such modification takes place during the ironing of the fabric advantageously enhances the stability of the modification.

Further features and advantages of the invention will become more evident in light of the detailed description of a preferred but not exclusive embodiment of a shrinking machine according to the invention, illustrated by way of non-limiting example with the aid of the accompanying drawings, wherein:.

With reference to the mentioned figures and, in particular, to <FIG> and <FIG>, described herein is a shrinking machine <NUM> for fabrics T.

It comprises a flexible belt <NUM> with which the fabric T to be shrunk is arranged in contact. Said belt <NUM> is arranged in a closed loop around some rollers <NUM> among which an inlet roller <NUM> and an outlet roller <NUM> are identified. The first corresponds to the point from which the fabric T is arranged in contact with the flexible belt <NUM>, while the second identifies the maximum point of the path of the fabric T on the same belt <NUM>. By reaching the outlet roller <NUM>, the fabric T is taken from the flexible belt <NUM> to be conveyed to other processing steps.

For the shrinking of the fabric T, the machine <NUM> comprises an intermediate body <NUM> arranged next to the flexible belt <NUM> between the inlet roller <NUM> and the outlet roller <NUM>. On the outer surface <NUM> of the intermediate body <NUM>, a stretch <NUM> can therefore be identified which, with a corresponding stretch <NUM> of the flexible belt <NUM>, forms a sliding channel <NUM> for the fabric.

Therefore, the flexible belt <NUM>, during its sliding around the inlet roller, sees at least its outer surface extend. In this situation, it receives the fabric T, supporting it. Next, the same flexible belt <NUM> is subjected to at least one curvature decrease. As a consequence, the same outer surface of the flexible belt <NUM> is shrunk, which induces a shrinking of the fabric T.

The aforementioned sliding channel <NUM> advantageously allows, first of all, to keep the fabric T arranged in contact with the flexible belt <NUM> during its shrinking. Furthermore, since the intermediate body <NUM> is typically heated, in the channel <NUM> there is a heat transfer to the fabric T in order to stabilize its shrinking. In other words, the shrunk fabric is ironed in the channel <NUM>.

From the drawings it can be observed that the stretch <NUM> of the intermediate body <NUM> which shares the construction of the channel <NUM> is convex. Moreover, the intermediate body <NUM> is arranged in contact with the flexible belt <NUM> in the corresponding stretch <NUM>. In this way, the corresponding stretch <NUM> is shaped with a concavity <NUM> which in substance is immediately downstream of the convexity <NUM> generated by the inlet roller <NUM>. Consequently, the flexible belt <NUM>, in the transition from the convexity <NUM> to the concavity <NUM>, also undergoes a bending inversion which ends the shrinking effect exerted on the fabric T. In other words, advantageously, the fabric T, which is arranged in contact with the belt <NUM> in its extended stretch corresponding to the convexity <NUM>, starting from a surrounding area of the curvature inversion point, is substantially shrunk by the narrowing of the belt <NUM> in the concavity <NUM>.

Obviously, this feature should not be considered as a limiting feature for the invention. As can be deduced from the foregoing, in fact, for the purposes of fabric shrinking, a reduction of the curvature of the flexible belt is sufficient, the zeroing or the inversion of the same allowing only to increase the shrinking effect. In this sense, therefore, according to a variant embodiment of the invention, not shown in the figures, the sliding channel is rectilinear, with the absence of the curvature inversion point of the flexible belt.

The intermediate body <NUM> contributes to shrinking, primarily by favouring the change in curvature of the belt <NUM>. Moreover, it is generally heated to perform the ironing of the fabric T mentioned above so as to stabilize shrinking over time.

However, as stated, such stabilization does not yet allow the subsequent elongation of the fabric T to be avoided, which is not negligible.

For this reason, according to an aspect of the invention, the shrinking machine <NUM> also comprises a limited-area pressure element <NUM> arranged between the intermediate body <NUM> and the flexible belt <NUM>. In particular, this pressure element <NUM> defines a pressure area with a mainly longitudinal development and which develops transversely to the feed direction of the fabric T.

In particular, as mentioned, the pressure area, being mainly longitudinal and transverse to the feed direction of the fabric T, is similar to a strip that is as long as or more than the width of the fabric T and of a particularly limited width so as to be similar to a pressure line. In this way, in the feed direction of the fabric T, the additional pressure exerted is substantially punctual.

This allows the limited-area pressure element <NUM> to press the fabric T at a point in the concavity <NUM> of the flexible belt <NUM> coinciding with the curvature inversion point. In other words, the limited-area pressure element <NUM> acts when the shrinking force exerted on the fabric T is maximal.

Although it has just been said that the limited-area pressure element <NUM> at a point which is coincident or subsequent to the curvature inversion point <NUM> of the flexible belt <NUM>, according to what has been said above, it is clear that this aspect must not be considered as limiting for the invention. According to some embodiments not shown in the figures and in any case falling within the scope of protection of the present patent, the limited-area pressure element acts at the inlet point of the sliding channel, whereas according to other variants it acts at any point of the channel following this inlet.

In any case, this advantageously allows to maximize the effect of the pressure exerted, i.e. to maximize the stabilizing effect it has on the compressed fabric T.

In fact, the punctual pressure acts mechanically on the mesh of the fabric T modifying it so that it does not subsequently release its shrinking.

However, since this pressure is punctual, it does not appear to be drastic on the fabric T, thus avoiding ruining its quality.

The intermediate body <NUM>, as previously said, typically exerts an ironing of the fabric T. Because the limited-area pressure element <NUM> is interposed between the intermediate body <NUM> and the fabric T, it is in itself evident that it exerts a considerable pressure, although limited in space.

Still advantageously, since the limited-area pressure element <NUM> acts during the ironing of the fabric T, the obtained effect is even more accentuated, allowing to maximize the stability of the fabric T after the treatment.

Again and advantageously, as a consequence, with the same shrinking effect, the path of the fabric T in the ironing section can be reduced, that is, still advantageously, an increase in the production speed and, therefore, a better economic yield of the machine <NUM>, can be obtained. Also, in terms of power consumption, there is an advantageous gain, since the amount of heat necessary for the ironing itself is lower and the power required to move the various components of the machine is lower.

According to a variant embodiment not shown in the figures, the shrinking machine also comprises a thrust element arranged opposite to the limited-area pressure element on the other side of the conveyor belt. It acts on the conveyor belt and on the fabric in the direction of the pressure element.

This thrust element may consist of a cylinder or other without any limitation for the invention. What matters is that it acts at least at the pressure element. In this way, advantageously, the effect of the latter on the fabric is accentuated.

However, excessive pressure could damage the tissues. In this sense, according to further embodiments, the thrust element exerts an adjustable thrust so as to adapt it to the need and, in particular, to the fabric to be treated. Advantageously, the effect of the pressure element is thus increased and optimized according to the fabric being processed.

In order to ensure the best possible adhesion of the fabric T to the belt <NUM> in correspondence with the inlet roller <NUM> (that is, in the stretch of maximum extension of the belt <NUM>), the shrinking machine <NUM> also comprises a sheet <NUM> arranged in contact with the flexible belt <NUM> a starting from a point of the belt in correspondence of the inlet roller <NUM> and terminating at a subsequent point the curvature inversion point of the flexible belt <NUM>. This sheet <NUM> is supported by a special first cylinder <NUM> arranged near the inlet roller <NUM>. Obviously, the presence of the first cylinder must not be considered limiting for the invention, the sheet being supported by any other type of component.

Advantageously, therefore, the sheet <NUM> keeps the fabric T in position until after the curvature inversion point of the belt <NUM>, i.e. up to the shrinking of the fabric T itself.

Although mentioned and shown in the figures, this sheet must not be considered as limiting for the invention since there are some embodiments where it is absent.

Since the action of the sheet <NUM> results in a pressure exerted on the fabric T towards the belt <NUM>, according to the embodiment which is described, the starting point of this action is located laterally to the inlet cylinder <NUM> positioning the first cylinder <NUM> at least sideways to the same inlet cylinder <NUM>.

Advantageously, therefore, the fabric T is also shaped with a convexity <NUM>. The latter exerts a pressure action on the fabric T which accentuates its adherence to the belt <NUM>.

However, despite this expedient, the sheet <NUM> is not always able to correctly adhere the fabric T to the belt <NUM>, especially in the case of difficult fabrics.

For this reason, according to an aspect of the invention, the machine <NUM> also comprises a pair of tensioning elements <NUM> of the sheet <NUM> arranged at the end portions of the sheet <NUM> itself.

This advantageously allows increasing the thrust force exerted by the sheet <NUM> on the fabric T towards the belt <NUM>. This force allows to adhere to the belt <NUM> also fabrics T that usually "refuse" shrinking.

Still advantageously, this pressure makes it possible to increase the adhesion of the fabric T in the stretch of greater extension of the flexible belt <NUM> and, consequently, to increase the shrinking effect exerted on the fabric T in the subsequent compression of the belt <NUM>.

Since the increase in pressure exerted is in fact discharged on the flexible belt <NUM> and on the underlying inlet roller <NUM>, this feature could force to increase the dimensions of the inlet roller <NUM> to avoid possible unwanted bending. This increase in size, however, would decrease the shrinking effect exerted on the fabric T.

To avoid this, according to another aspect of the invention, the shrinking machine <NUM> comprises a support body <NUM> of the inlet roller <NUM>. In the embodiment that is described, the support body <NUM> is constituted by a support roller <NUM> located below the inlet roller <NUM>, but this aspect must not be considered limiting for the invention.

Likewise, the number and the form of execution of the flexible belts, of the rollers, of the intermediate bodies, of the sheets and of the tensioning elements must not be considered as limiting.

With regard to the latter, according to another aspect of the invention, a first of them consists of the first cylinder <NUM> which supports a first end portion of the sheet <NUM> retaining it.

According to a further aspect of the invention, a second <NUM> of the tensioning elements <NUM> is constituted by means for fixing the second end portion of the sheet to the outer surface <NUM> of the intermediate body <NUM>. The embodiment of the aforesaid fastening means is indifferent to the scope of protection of the present patent, since they can consist of adhesives, screw means, joints made on the intermediate body or other.

What is evident in the first instance is that, according to this embodiment, the intermediate body <NUM> is a fixed and non-moving element. In this sense, the embodiment of the same represented in the figures and constituted by a cylinder must not be considered as limiting the invention. In particular, the intermediate body <NUM> can have any shape and profile.

However, even these aspects of the invention should not be considered as limiting. In particular, according to an embodiment variant not shown in the figures, the second tensioning element comprises means for thrusting the second end portion of the sheet against the outer surface of the intermediate body. In this sense the latter could be rotating and therefore shaped like a cylinder or similar.

A further embodiment of the machine of the invention, not shown in the figures, shows the second tensioning element comprising a second cylinder to which the second end portion of the sheet is stably coupled. In particular, the second cylinder is arranged operatively downstream of the intermediate body, for example near the outlet roller. Even in this case, obviously, the intermediate body can be rotating.

Since, from what has been said, it is clear that an important aspect of the shrinking machine <NUM> of the invention is the increase of the pressure exerted by the sheet <NUM> on the fabric T against the flexible belt <NUM> at least in correspondence with the inlet roller <NUM>, the same sheet <NUM> is subject to greater stresses that could compromise its integrity.

For this reason, according to a further aspect of the invention, the sheet <NUM> is constituted by a metal mesh.

Advantageously, this embodiment allows to considerably increase the tensioning of the sheet <NUM> and its consequent effects on the fabric T.

Still advantageously, it improves the wear resistance over time of the sheet <NUM> with respect to the known sheets even in the absence of tensioning.

Typically, the metal mesh is of the type woven on a loom, to optimize its flexibility, but also this aspect must not be considered limiting for the invention.

In any case, the same mesh is appropriately subjected to abrasion treatment with abrasive paste that not only smooths out any protrusions, but also fills any depressions, reducing the roughness. Finally, typically, a polishing treatment is carried out to obtain the best possible result.

As regards the aforementioned limited-area pressure element <NUM>, according to the embodiment described herein, it consists of a cylinder with a mainly longitudinal development arranged in contact with the intermediate body <NUM>. In other words, it is similar to a rod or the like.

It is permanently coupled to the sheet <NUM>, i.e. the shoe, to stabilize its position. However, such aspect must not be considered limiting for the invention. According to some embodiments, in fact, it is permanently coupled to the casing of the shrinking machine <NUM>.

However, according to other embodiments, not shown here, it is coupled to the intermediate body. In this case, obviously, it is a variant of the above-mentioned shrinking machine and in which the intermediate body is stationary.

In this sense, it is also evident that the aforementioned same embodiment of the limited-area pressure element should not be considered limiting for the invention. For example, in the case of a shrinking machine with a stationary intermediate body, according to an embodiment not shown in the figures, the limited-area pressure element consists of a rib protruding from the intermediate body.

In light of the foregoing, it is understood that the shrinking machine of the invention achieves all the prefixed purposes.

In particular, it allows the correct processing also of difficult fabrics which, in the known machines, tend to refuse shrinking.

On closer inspection, it also makes it possible to improve shrinking maintenance of fabrics leaving the processing avoiding, at the same time, lowering of production speed.

This machine, however, has small dimensions and low consumption both in mechanical terms and in terms of developed heat, while guaranteeing a degree of shrinking that is durable over time and superior to known equivalent machines.

Claim 1:
A shrinking machine for fabrics (T), comprising:
- at least one flexible belt (<NUM>) for supporting and transporting a fabric (T), said flexible belt (<NUM>) being arranged in a closed loop around at least one inlet roller (<NUM>) and at least one outlet roller (<NUM>);
- at least one intermediate body (<NUM>) of which at least one stretch (<NUM>) of the outer surface (<NUM>) identifies with a corresponding stretch (<NUM>) of said flexible belt (<NUM>), between said two rollers (<NUM>, <NUM>) a sliding channel (<NUM>) for the fabric (T);
characterized in comprising at least one limited-area pressure element (<NUM>) disposed between said intermediate body (<NUM>) and said flexible belt (<NUM>) to define a pressure area having a shorter length of one or more orders of magnitude with respect to the width so as to be comparable to a line and which develops transversely to the feed direction of the fabric (T) to press the fabric (T) at a point of said sliding channel (<NUM>).