FR2553440A1 - METHOD AND APPARATUS FOR COMPRESSION SHRINKAGE OF A FABRIC - Google Patents

Abstract

APPARATUS CHARACTERIZED IN THAT IT INCLUDES A FLEXIBLE BELT16, MEANS17, 18, 19 TO GUIDE AND DRIVE THIS BELT ON A CLOSED CURVILINE LOOP TRAJECTORY, THIS BELT16 INCLUDING ON ITS SIDE TURNS TO THE OUTSIDE OF THE LOOP, FRICTION 16 INTENDED TO COME IN CONTACT WITH THE SURFACE OF THE PIECE OF FABRIC12, AN EXTENDED FLEXIBLE SHEET22 CARRYING A LOW FRICTION COEFFICIENT SURFACE, MEANS24, 25 FOR APPLYING PRESSURE TO THE SHEET PLACED AGAINST THE BELT, AGAINST THE BELT A ZONE OF COMPRESSION BETWEEN THE BELT16 AND THE SHEET 22. The invention relates to a method and apparatus for the compression shrinkage of a fabric.

Description

METHOD AND APPARATUS FOR COMPRESSION SHRINKAGE OF A FABRIC

  The present patent application is a supplement to the earlier patent application of the present invention under No. 542,794 on October 17, 1983.

  The invention relates to a method and a new apparatus for the mechanical pre-stripping of

  fabric, and in particular of closely knit fabric.

  The apparatus utilizes, at least in part, a tissue shrinkage technique illustrated in US Patent No. 4,156,955. As shown in this patent, a Teflon coated fiberglass sheet is held at one end against a dryer. or a drum type wringer, such that the sheet and its free end pass between the drum and a continuous felt belt surrounding the drum circumference. The fabric can penetrate the nip formed between the fiber sheet teflon-coated glass and the felt strap that allows

  3 G to compress or preshrink it.

  Although the compression shrinkage device described above is very efficient and allows, by the very fact of its construction and operation, to save a lot of investment costs, the method implementing this device nevertheless allows to obtain tissue shrinkage rates generally in the range of about six to twelve percent. This is sufficient for some applications, but there are cases requiring prerequisites that are greater than

  described above allow to obtain.

  The object of the invention is therefore to create a compression shrinkage system using certain characteristics of the system described above, but allowing, for a shrinkage by compulsion,

  either simple or double, to obtain higher degrees of shrinkage than those of the prior art.

  To this end, the invention relates to an apparatus for mechanically introducing a longitudinal compression into a piece of fabric, characterized in that it comprises a flexible belt, means for guiding and driving this belt on a closed curvilinear loop path. , and drive roll means for producing the curvature of portions of the belt as it passes around the roller means, said belt having on its side facing out of the loop a friction intended to come into contact with the surface of the piece of fabric, the guide and drive rollers defining with the belt, spaced curved portions of said belt and relatively straight intermediate portions between the curved portions, a flexible sheet elongate bearing a surface with a low coefficient of friction, means for attaching an end of the flexible sheet in the vicinity of a curved portion of the belt, means for applying the pressure to the sheet placed against the belt a distance corresponding to a straight portion thereof in the direction of movement of the belt, so as to define a compression zone between the belt and the sheet, means for varying the value of the pressure applied by the pressure means, and

  means for introducing the tissue into the compression zone so as to effect compression thereof.

  According to another characteristic of the invention, the means for applying the pressure to the sheet, so as to form a compression zone between the belt and the sheet, is constituted by a flat member which can be heated and conduct heat towards the sheet for producing steam and thus reducing the friction between this vapor and the tissue passing on the sheet Another way to apply the pressure above is to use a bladder

  inflatable, which may contain a heated fluid to obtain the same result.

  The invention also relates, if it is necessary to obtain an additional degree of compression, the use of a second compression stage which, in its main aspects, is similar to the stage of compression.

  compression described in the bravet U S A No. 4 156 955.

  If this second compression stage is used, the apparatus and method according to the invention relate to the use of a flexible sheet of the first compression stage for transporting the roll of fabric in this second stage under relatively high tension. low, so as to reduce the pulling risk of decreasing the compression obtained in the fabric after pressing in the

first floor.

  The invention will be described in detail with reference to the accompanying drawings in which: Figures 1 and 2 show a compression device for fabric parts using two compression stages according to the invention; and, Figures 3 and 4 show a single compression stage using an inflatable device to apply pressure to the sheet at

  the location of the compression zone.

  Referring first to Figure 1 of the drawings, this is a dual compression apparatus 10 according to the invention. This apparatus 10 comprises a steam box 11 through which a piece of fabric 12 consisting of, for example, A flattened tubular piece of closely knit fabric passing, as illustrated in the figure, on an internal spreading device. It is obvious that the apparatus can advantageously be used on open widths of tight tissue (single layer). The wetting fabric passes over a guide roll 13 and then enters the first stage 14 of the double compression device according to the invention. The compression stage 14 comprises a continuous flexible belt 16 which, in the form

  embodiment shown here is in felt.

  In other applications, the belt may be of rubber or any other suitable material. The belt 16 passes around the rollers 17, 18 and 19, the surface of these rollers 17 to 19 consisting of rubber coming into contact with each other. friction against the inner surface of the belt 16 Either or both of the rollers 18 and 19 may be driving rollers advancing the belt 16 in the direction of the arrows An envelope guiding roll 20, outside the 30 belt buckle, is used to hold the belt

  16 centered with respect to the adjacent parts.

  Next to and below the roller 13 is a bracket 21 for mounting and anchoring

  cylindrical which can be attached to one end of a flexible sheet 22 made of fiberglass coated

  Teflon green or any other equivalent material.

  The sheet 22 is wrapped around the bracket 21 and its length is sufficient to come under most of the horizontal length 16 'of the flexible belt 16 When the free length 22' of the sheet 22 is supported, as illustrated in the figure, by a flat and rigid sheet support member 23, this element 23 can come closer and stare away from the portion 16 'of the belt 16 and tighten to a position to bring the end of the sheet 22 'in contact with the adjacent surface of the belt 16, by means of bolts 24, 25 being able to move vertically in sheets 26, 27 of a mounting bracket 28 This movement makes it possible to apply 1 different pressures on the length of sheet 22 'to ensure that the fabric does not form a loop in the compression zone Lthe heating element 29 provides heating of the support member 23 and

the length of sheet 22 '.

  As a result, a compression zone is formed between the belt length 16 'and the length 22' of the flexible sheet through which the piece of fabric 12 can pass. The piece of fabric 12 enters this area after being contacted. friction with the lower surface of the belt 16 and after having begun to pass around the curved portion 30 of the belt 16 defined by the curvature of the roll 19 When the piece of cloth 12 continues to advance in the compression zone formed between the belt portion 16 'and the portion 22' of the flexible sheet, this piece of fabric 12 is compressed in a conventional manner in the direction of its course As the piece of cloth has been previously wet, the heat produced by the The heating element 29 and transmitted through the portion 22 'of the flexible sheet causes the evacuation of a certain amount of moisture from the piece of fabric in the form of steam providing lubrication. However, this lubrication is already ensured by the presence of the Teflon coating on the sheet 22. The device thus described above, that is to say the compression stage 14, can be expected to shrink or longitudinally compressing the piece of cloth by six to twelve percent, it being understood that the degree of compression can be varied to a certain extent by varying the curvature of the roll 19, as well as the thickness and nature of the material of the belt 16. Just one side of the compression or contraction stage 14 is a compression stage 15 comprising a heated drying drum 31 surrounded by a continuous felt belt 32 whose displacement in the direction of the arrows causes the drum 31 to rotate clockwise The belt 32 is driven by the drum 31 and this movement of the belt is supported by the rollers 33 and 34 Just above the roll at 34 is a bracket-36 to which is attached by its lower end, the end of a sheet

  flexible 37 of the same construction as the sheet 22.

  The remainder of the sheet 37 is placed between the drum 31 and the face of the belt 32 facing the drum, and this is the frictional contact between the free end 37 'of the sheet 37 and the drum 31, as well as This thinning, as well as the tension of the belt 32 and its contact with the drum 31, produces a niping zone between the drum and the drum.

  part 32 'of the belt and part 37' of the sheet.

  After having passed through the nip zone of the compression stage 14, the fabric 12 advances between the belt 32 and the flexible sheet 37 following the curvature defined by the roll 34, and then in the nip zone between the part belt 32 'and the leaf portion 37' passing through this area is from

again compressed.

  It will be appreciated that a very short space 38 exists between the end of the sheet 22 and the beginning of the sheet 37, and that the tension of the piece of fabric 12 can be seen as it passes into this space. the embodiment illustrated here, there is shown a very slight downward curvature which could indicate the complete absence of tension of the piece of fabric 12 If the piece of fabric 12 was stiffened in the space 38, this would indicate a state longitudinal tension and the fact that at least part of the compression introduced into the piece of fabric by the compression stage 14 would have

deleted or eliminated.

  Referring now to FIG. 2, this represents an alternative embodiment of the invention. As the embodiment of FIG. 2 uses exactly the same mechanical elements as those described in FIG. 1, with the exception of the two flexible sheets 22 and 37, the same references have been used to denote the same parts or elements appearing in FIG. 2 In this embodiment of FIG. 2, it will be noted that a single sheet 40 is attached to the console 21 of the same way that the sheet 2 was attached to the console 21; however, the sheet 40 extends lengthwise to pass around the roll 41, and its end portion 40 'passes along the

8 2553440

  drum 31 to come between the belt of felt 32

and the drum.

  However, in the embodiment of FIG. 2, the piece of fabric 12 is first compressed into the nip formed between the lower portion 16 'of the flexible belt 16 and the portion 40 "of the flexible sheet. Next, the piece of fabric 12 passes along the upper surface of the sheet 40 (as shown in Fig. 2) before passing around the roll 41 and entering the nip defined by the portion 40 'of the sheet 40 and the portion of the felt belt 32 When the piece of fabric 12 passes from the stage 1 to the stage 2 of the compression device, this piece of fabric is exposed in a space 38 'where one can observe its degree of tension Generally the piece of cloth is found without any tension in

  this space and may be a little wrinkled, but as it is supported by the sheet 40 above, this piece of cloth is not affected by its weight.

  As a result, there is no reason for the compression applied to the piece of fabric in the first

  This shrinkage stage is eliminated when this piece of cloth is transported on the sheet 40 to the second compression stage.

  The apparatus of FIG. 1 may be preferred to the apparatus of FIG. 2, since the compression of the fabric in the different stages is applied to the two opposite sides of this fabric; That is to say that the sliding of the fabric against the respective sheets 22 and 37 is with respect to the opposite faces of the fabric, which makes it possible to eliminate the single-face treatment. The apparatus of FIG. 2 can, for this However, it nevertheless illustrates the basic principle of the invention that the piece of fabric is supported throughout its length by a flexible compression sheet, when this piece of fabric passes through two stages of compression. The apparatus of FIG. 2 may advantageously be used to pre-shrink a non-tubular tissue in which it may be desirable to expose only one side of the tissue to the sliding effects with respect to the tissue.

flexible sheet 40.

  Referring now to FIGS. 3 and 4, these show an alternative method and apparatus for applying pressure to a flexible sheet used to shrink the fabric and define the compression zone in the apparatus of FIG. 3. and 4, a conventional endless rubber belt 50 passes around the rollers 51 and 52 (of which

  one or both may be driving rollers), and around a small diameter roll 53.

  The roller 53 is rotatably supported in the frame 54 which also serves to mount the rollers 56, 57 and 58. The latter are mounted so as to abut against the inner surface 50a of the belt 50 to prevent the deflection of the belt in

  the area delimited by the rollers 56 to 58.

  A chassis or bracket 59 is located right next to the roll 53, but outside the closed loop constituted by the rubber belt 50. In the frame 59 is housed a flexible sheet mounting bar 60 fixed to the chassis by a small rod 61 preventing the rotation of the bar 60 relative to the frame 59 A teflon-coated fiberglass flexible sheet 62, as shown in US Pat. No. 4,156,955, is attached to the bar 60 by passing its portion end 62a around the bar 60 and fixing this end portion 62a against a flattened area of the bar

  a, by means of screws 63 and a retaining plate 64.

  The flexible sheet 62 is allowed to pass around the upper portion of the belt 50 (as shown in FIG. 3) along the outside thereof, in the vicinity of the roll 53. The fabric 65 is admitted between the outer surface 50 b, the belt and the inner surface 62a of the sheet 62 after passing over the tensioner 66 In the embodiment illustrated here, the fabric is a textile material

tubular tight woven.

  The sheet 62 comes against the outer surface 50b of the belt 50, a distance which, in the embodiment illustrated here, exceeds a little beyond the position of the roller 57 In the area coming laterally in the vicinity of the roller 53, to a position approximately adjacent to the roller 57, the apparatus forms a compression zone in which the fabric 56 is compressed according to well-known principles The fabric is in frictional contact with the outer surface 50 b of the belt 50 and after passing around the arc defined by the belt 50 and the roller 53, this tissue is compressed between the belt 50 and the sheet 62. The degree of compression depends on the curvature of the belt produced by the belt 50. roll 53, and is performed in the compression zone between the outer surface 5 C-b 'and the inner surface 62 respectively of the belt 50 and the sheet 62, insofar as the sheet 62 prevents the tis to train

  loops in the compression zone The means for preventing phenomena will now be described.

  Just beside the compression zone is an apparatus consisting of a box-shaped beam 67, a retainer 68, and an inflatable bladder 11. The box-shaped beam 67 and the bladder 69 are disposed longitudinally in the box. width of the fabric to be compressed The ends of the beam 67 (not shown) are attached to adjacent frame members (not shown), and a retainer 68 can slide along the beam so as to be able to locate itself. to properly retain the bladder 69, the rim of the retainer 68 being to prevent movement of the bladder relative to the beam 67. As a result, air or any other suitable fluid (which may be heated to produce steam from the wetted tissue, as it passes into the compression zone), can enter the bladder 69 through fluid splashing 70, and fluid pressure within the bladder 69 the The pressure exerted by the bladder 69 against the sheet 62 must be sufficient to prevent the tissue from forming loops in the compression zone 67. pressure can be adjusted accurately in order to vary conditions such as compression speed, fabric thickness etc.

  in order to obtain a uniform compression of the desired degree.

  The support formed by the frame 54 and the rollers 56-58 constitutes a low-friction support support (solid), for the belt 50, so as to enable it to withstand the pressure exerted by the bladder 69 and not to In the embodiment illustrated here, the roller 53 is very small, so that the curvature of the belt around the roller 53 is more pronounced than if this roller 53 were larger. The reduction of the radius of curvature produces greater compression in the compression zone, so that it is extremely important to hold the flexible sheet 62 firmly and firmly against the tissue as it passes through the compression zone. bladder 69 is in itself flexible and can conform to the surface of the sheet 52 over the entire width of the fabric which may vary, to a certain extent, depending upon the

  characteristics of this fabric and the compression produced in the compression zone.

  It being possible for the fabric to be further subjected to a second compression stage such as that of FIGS. 1 and 2, after it has been compressed in the apparatus of FIGS. 3 and 4, because the the curvature of the belt 50 around the roller 53 is very large, it is very likely that a high compression percentage can be obtained in a single compression stage when using the

  configuration and apparatus of Figures 3 and 4.

Claims (8)

  Apparatus for mechanically introducing a longitudinal compression into a piece of cloth, characterized in that it comprises a flexible belt (16), means (17, 18, 19) for guiding and driving this belt on a looped path curvilinear closed, and drive roll means 10 for producing the curvature of certain portions of the belt as it passes around the roller means, said belt (16) having on its outwardly facing side the loop, a friction surface (16 ') intended to come into contact with the surface of the piece of fabric (12), the guide and drive rollers defining with the belt, spaced curved portions of this belt and relatively straight intermediate portions between the curved portions, an elongated flexible sheet (22) having a low friction surface, means for attaching an end of the fire it is flexible in the vicinity of a curved portion (30) of the belt, means (24, 25) for applying the pressure to the sheet placed against the belt a distance corresponding to a straight part thereof in the direction of the belt. moving the belt so as to define a compression zone between the belt (16) and the sheet (22), means (24, 25) for varying the value of the pressure applied by the pressure means, and means for introducing the tissue into the compression zone so as to effect the compression of it.   2 Apparatus according to claim 1, characterized in that the means for applying the pressure consist of a flat member relatively not flexible.   3 Apparatus according to claim 1, characterized in that the means for applying pressure are constituted by an inflatable flexible bladder (69).   4 Apparatus according to claim 1, characterized in that the means (29) for applying the pressure are heated to release steam in the compression zone.   Apparatus according to any one of   Claims 1 to 4, characterized in that it comprises   in addition a heated drying drum, means for rotating the drum, a continuous flexible envelope surrounding the major part of the drum circumference, means for introducing a piece of cloth between the drum and the envelope so as to dry this a piece of fabric as it is driven around the drum, these means comprising a curved portion of the envelope, an elongate flexible sheet having a low friction surface, means for introducing the free end of the sheet between the envelope and drum and for introducing the piece of cloth between the flexible sheet and the wrapper after the piece of cloth has passed around the curved portion of the wrapper, this wrapper and the sheet then defining a nip in which an additional compression of the piece of cloth.   Apparatus according to claim 5, characterized in that the sheet consists of two parts of which at least one is attached in the vicinity of   means for introducing the fabric into the drying drum.   Apparatus according to any one of claims 5 and 6, characterized in that the 2553440   leaves are separated by a short distance over which the piece of fabric can pass without being supported by either sheet, thereby indicating the degree of longitudinal tension applied to this piece of fabric before it is subjected to compression in the second nipping zone 8 Method implementing the compression apparatus of a piece of tissue, according to any one   Claims 1 to 7, characterized in that it comprises the various steps of passing the workpiece   of fabric, in frictional contact around a flexible belt, along a curved path, and then along a straight path, to form a compression zone in the straight path portion of the fabric piece by pressing it against a straight portion of the belt by means of a low-friction sheet, applying pressure to the sheet over the entire area of the compression zone and varying this pressure to suit the speed of passage of the workpiece 20 tissue, the thickness of the fabric, and the degree of compression to obtain.   9 Method implementing the apparatus according to claim 8, characterized in that it comprises the step   consisting of producing steam on the compression zone 25 heating the fabric.   Process using the apparatus according to any one of claims 8 and 9, characterized in that   it comprises the step of subjecting the fabric to a second compression step and transporting the fabric in a substantially voltage-free state between an initial compression stage and a second compression stage