GB2103670A

GB2103670A - Stress-relieving fabric

Info

Publication number: GB2103670A
Application number: GB08214867A
Authority: GB
Inventors: Heinz Joseph Gerber
Original assignee: Gerber Scientific Inc
Current assignee: Gerber Scientific Inc
Priority date: 1981-07-20
Filing date: 1982-05-21
Publication date: 1983-02-23
Also published as: FI822538A0; FI822538L; KR840000704A; IT8267921A0; JPS5836263A; KR860000404B1; FR2509760A1; ES8401413A1; ES524983A0; IT1155559B; ES513633A0; DE3224776A1; ES8406362A1

Abstract

Fabric stored on a supply roll is stress relieved by paying it off the supply roll and vibrating a slack portion of the fabric while it is being payed-off. The fabric may be further excited to hasten relaxation of tension within its fibers by heating it and/or passing air through it while it is being vibrated. As shown in Fig. 1, fabric F from a roll or bolt B is laid on a table 12 by a carriage 16. A slack portion is formed between feed rollers 22, 22' one or both of which is or are vibrated axially and/or radially to stress relieve the fabric. The presence of the slack portion is determined photoelectrically. In other embodiments, a plate (52) on which the fabric is laid is vibrated, Fig. 3 (not shown); ultrasonic vibrations are utilized to induce vibratory motion in the untensioned fabric, Fig. 4 (not shown); and, instead of being laid, the fabric is re-wound, Fig. 5 (not shown). <IMAGE>

Description

SPECIFICATION Apparatus and method for stress-relieving fabric Background of the Invention This invention relates in general to apparatus and methods for working on fabric and deals more particularly with improved apparatus and methods for relieving stresses in fabric which is made up into a roll or bolt preparatory to further processing.

In the manufacture and processing of cloth, it is customary for the fabric to be made up into rolls or bolts for convenience in handling and storage. The process of winding cloth onto a roll or bolt subjects the material to tensional and compressional stresses which produce temporary, but significant, changes in the length and width dimensions of the material. If patterns are marked on or cut from the fabric too soon after it is unrolled, shrinkage or relaxation of the material which occurs after the pattern marking or cutting operation may cause serious errors in the size of the finished goods. An accepted procedure for overcoming this problem is to spread the material upon a supporting surface and allow sufficient time for the material to relax or shrink to its normal size. Only then can cutting, printing or other size-dependent operations be performed on the material.This waiting period may necessitate costly machine downtime. Further, the provision of special table facilities to accommodate the material, during the waiting period, while it is allowed to relax or shrink, adds further cost to the operation in the form of increased floor space requirements. The present invention is concerned with the aforesaid problems.

Summary of the Invention Fabric to be spread upon a working surface from a supply roll or bolt is stressed relieved by paying the fabric off of the roll or bolt to provide a slack region of payed-off fabric and vibrating payed-off fabric within the slack region whereby to accelerate relaxation of residual stresses within the fabric. An apparatus for stress-relieving fabric stored on a rol! or bolt includes means for payingoff fabric from the roll or bolt, means for maintaining a region of the payed-off fabric in slack condition, and means for vibrating payed-off fabric within the slack region.

Brief Description of the Drawing Fig. 1 is a somewhat schematic side elevational view of a fabric spreading apparatus in accordance with the present invention and illustrates a method for stress-relieving fabric.

Fig. 2 is a somewhat enlarged fragmentary perspective view of a portion of the apparatus in Fig. 1.

Fig. 3 is a somewhat schematic fragmentary perspective view of another machine embodying the present invention and illustrates another method for stress-relieving fabric.

Fig. 4 is a somewhat schematic fragmentary side elevational view of still another machine embodying the present invention and illustrates still another method for stress-relieving fabric.

Fig. 5 is similar to Fig. 4, but illustrates yet another machine and method for stress-relieving fabric.

Detailed Description of Preferred Embodiments and Methods Turning now to the drawing, and referring first particularly to Fig. 1, a fabric spreading apparatus embodying the present invention and illustrating a method for relieving residual stresses in fabric is indicated generally by the reference numeral 1 0.

The apparatus 10 may, for example, comprise a part of a machine for working on a single sheet or layup of fabric, such as an automated cutting machine for cutting patterns from fabric in accordance with a predetermined program, and includes a lay table assembly 12 which has a generally horizontally disposed and upwardly facing working surface 14. The spreading apparatus 10 further includes a carriage assembly indicated generally at 1 6 and supported on ways mounted on the table assembly 12 for reciprocal movement longitudinally of the working surface 14 in one and an opposite direction, as indicated by directional arrows in Fig. 1.The illustrated carriage assembly 1 6 is driven by a drive unit (not shown) and may be arranged to move relative to the working surface 14 in response to signals received from a programable numerical controller (not shown), in a manner well known in the fabric processing art. A pay-off mechanism, indicated generally at 1 8 and mounted on the carriage assembly 1 6, supports a roll or bolt of fabric indicated by the letter B, the fabric being indicated by the letter F. The bolt B is supported for rotation about an axis which extends transversely of the working surface 14.A drive mechanism, which includes a motor 20, comprises part of the pay-off mechanism 1 8 and drives the bolt B to pay-off fabric from the bolt at a linear rate generally corresponding to the rate of relative linear movement between the carriage assembly 1 6 and the working surface 14.

In accordance with the invention, at least one feed roller 22 is supported on the carriage assembly 1 6 for rotation about an axis parallel to the axis of the bolt B. Preferably, and as shown, the apparatus 10 includes a plurality of feed rollers 22, 22'. The feed rollers 22, 22' are driven in timed relation to the bolt B and to each other by a drive mechanism 24 and function to maintain a free handing loop of payed-off fabric F in a substantially slack condition within a region R between the rollers 22, 22'.

It is recognized that the longitudinally extending fibers of the fabric F within the region R may be under slight tension due to the weight of the fabric which comprises the free hanging loop, however, the magnitude of this stress is negligible as compared to the magnitude of stress to which the fibers are subjected when the fabric is wound to form the bolt B. A sensing device, such as a photosensor indicated generally at 26, which may, for example, comprise a photocell, phototube, phototransistor, or the like, indicated at 27, and a light source 28 is preferably connected through an amplifier 30 to the drive motor 20 and/or the drive mechanism 24 to control dispensing of fabric whereby a free hanging loop of slack fabric is at all times maintained within the region R between the rollers 22, 22'.

Further, and in accordance with the invention, means is provided for vibrating payed-off fabric F within the region R to effect mechanical excitation of the fabric whereby to relieve residual stresses in the fabric and thereby induce the material to rapidly return to its relaxed or normal state. In the illustrated embodiment 10 this vibratory motion is imparted to the fabric F by vibrating either or both of the rotating rollers 22, 22' in one or more directions. A preferred arrangement is shown in Fig. 2 where the roller 22, illustrated somewhat schematically, is shown supported for reciprocal vibration in an axial direction 32 and in radial directions 34 and 36.The roller 22 is further arranged for angular oscillation, as indicated at 38, while it is simultaneously rotated about its axis in a direction indicated by the directional arrow 40, as the spreader assembly 1 6 travels from right to left relative to the work surface 14, for example, as shown in Fig. 1.

Relaxation of the payed-off, slack fabric F may be further hastened by heating the fabric within its slack region R and/or by controlling humidity within the latter region. The fabric, may, for example, be heated by direct contact with a heated member, such as one of the rollers 22 or 22'. Alternatively, heated air within the region R may be utilized to heat the slack fabric or, if desired, a suitable heater, such as a microwave heater, may be provided for this purpose and may comprise a part of the fabric spreader 10.

The porous fabric F may be further mechanically excited by passing air through it. In the illustrated embodiment the roller 22 comprises a hollow perforated roller into which air may be forced or from which air may be withdrawn to cause air to flow through the perforated surface of the roller. A shoe 44, shown in Fig. 1 , which complements an associated portion of the peripheral surface of the roller 22, blocks openings in the roller which are not engaged by fabric to effect more efficient air movement through the fabric. Air is preferably withdrawn from the roller 22 so that air is drawn through the porous fabric to hold the fabric in engagement with the vibrating roller. Vacuum is, of course, maintained at low level so as not to apply significant stress to the fibers which comprise the fabric.

Referring now to Fig. 3, another machine embodying the invention is indicated somewhat schematically and illustrated generally by the reference numeral 42. The machine 42 includes a lay table assembly indicated generally at 44 which has a working surface 46. A carriage assembly, such as the carriage assembly 16, but not shown, is supported on the lay table assembly 44 to move in one and an opposite longitudinal direction relative to the working surface 46. The carriage assembly carries a bolt B1 and includes a pay-off mechanism (not shown) for paying fabric F1 from the bolt B1 onto the working surface 46 in timed relation to movement of the carriage assembly relative to the lay table assembly 44.The working surface 46 is defined by a plate 52 which comprises a part of the table assembly 44 and which is supported for vibrational movement in at least one direction. The illustrated plate 52 is supported for horizontal vibratory movement in both longitudinal and transverse directions indicated respectively by the arrows 54 and 56 and for vibratory movement in vertical directions indicated by the arrow 58. A suitable mechanical vibrating mechanism (not shown) is provided for imparting the latter motions to the plate 52.

The illustrated plate 52 is preferably perforated, as shown, so that air may be passed through it to impart further mechanical excitation to fabric supported on the plate. Preferably, vacuum is drawn on the underside of the plate 52 so that air is drawn downwardly through the porous fabric and through the plate 52. A relatively low level vacuum is maintained to avoid development of stresses within the fabric as it is drawn toward engagement with the plate 52. Alternatively, air may be forced upwardly through the perforations in the plate 52 and through the porous fabric supported on it. However, if this procedure is employed care must be taken to avoid excessive air pressure so that an air bearing will not be developed between the plate 52 and the fabric F1 to nullify the vibratory effect of the plate upon the fabric.If desired, the plate 52 may be heated whereby to heat the fabric and thereby further accelerate fiber relaxation.

In Fig. 4 there is shown another apparatus embodying the invention, indicated generally at 60, which utilizes sonic or ultrasonic vibrations to induce vibratory motion in cloth supported in an untensioned condition. The apparatus 60 includes a spreader assembly indicated generally at 62 which carries a bolt B2 and which includes a suitable pay-off mechanism (not shown) for unwinding fabric F2 from the bolt. The fabric F2 is fed into a chamber 64 where portions of the fabric pass over a plurality of driven rollers 66, 66 which maintain free hanging loops of fabric in substantially slack condition within the chamber 64. A sensing mechanism, such as the mechanism 26 hereinbefore described, may be provided for maintaining free hanging loops of fabric which defines a region of slack fabric, R'. An acoustic generator, such as indicated at 68, for propagating sonic or ultrasonic waves is disposed within the chamber 64 to impart vibrations to the loops of slack fabric in the region R', as the fabric passes through the chamber 64. Specifically, the payedoff fabric which comprises the loops is driven at a resonant frequency by energy from the adjacent wave generator 68. The characteristics of the waves which must be produced by the wave generator to effect sympathetic vibration of the fabric will, of course, be determined by the characteristics of the fabric being processed.

Various types of wave generators as, for example, whistles, horn-shaped matched systems, and audio drivers with exponential acoustic applicators may be utilized to produce outputs matched to the particular resonant characteristics of materials to be processed.

It will now be apparent that various combinations of vibration generating apparatus may be utilized to produce the desired vibrations within the fabric whereby to hasten its return to a normally relaxed state. Thus, for example, vibrations may be produced within the fabric by direct contact with a vibrating body or by sympathetic vibration whereby the fabric is caused to vibrate at a resonant frequency by energy from an adjacent system vibrating at the same frequency.

Referring now to Fig. 5, another machine embodying the present invention is indicated generally by the reference numeral 69. The machine 69 is similar in some respects to the machine 10 previously described, but includes a stationary roll stand 70 which supports a bolt B3.

A pay-off mechanism which includes drive motor 72 is provided to pay-off fabric F3 from the bolt B3 at a controlled rate. The payed-off fabric travels over a pair of rollers 74, 74 which are driven by a drive mechanism 75. The rollers 74, 74 advance the fabric F3 at a linear rate substantially equal to the linear rate at which it is unwound from the bolt B3 by the pay-off mechanism whereby a free hanging loop of material is maintained between the rolelrs 74, 74. A sensing mechanism indicated generally at 76 and substantially identical to the sensing mechanism 26 previously described, operates to maintain the free hanging loop of slack fabric in the region between the rollers 74, 74.

Either or both of the rollers 74, 74 may be vibrated in a manner as aforedescribed with reference to the roll 22 whereby to impart mechanical vibration to pay-off, slack fabric within the region of the free hanging loop. Further means may be provided to hasten relaxation of the fabric as by heating it, subjecting it to controlled humidity, or passing air through it, as has been hereinbefore discussed.

After the payed-off fabric has been vibrated it is wound onto a take-up roll indicated at T, supported on a take-up stand 78. A take-up mechanism 80 which includes a drive motor operates in timed relation to the drive motor 72 and drive mechanism 75 to wind the relaxed fabric in a substantially relaxed condition upon the takeup roll T whereby to avoid development of undesirable stresses within the material. After the material has been transferred from the bolt B3 to the take-up roll T, the take-up roll may be removed from the roll stand and transferred to other equipment for immediate use.

Claims

1. A method for stress relieving fabric stored on a supply roll and comprising the steps of payingoff fabric from the supply roll, controlling the pay off to maintain a slack region of payed-off fabric, and vibrating payed-off fabric within the slack region.

2. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 wherein the step of vibrating payed-off fabric is further characterized as continuously vibrating payed-off fabric as it is payed-off the supply roll.

3. A method for stress relieving fabric stored on a supply roll as set forth in either claim 1 or claim 2 wherein the step of paying-off the fabric is further characterized as advancing the fabric in engagement with a feed roller at a linear rate substantially equal to the linear rate at which the fabric is payed-off the supply roll and the step of vibrating payed-off fabric is further characterized as vibrating the feed roller.

4. A method for stress relieving fabric stored on a supply roll as set forth in claim 3 wherein the step of vibrating the feed roller is further characterized as vibrating the feed roller in at least one radial direction.

5. A method for stress relieving fabric stored on a supply roll as set forth in claim 3 wherein the step of vibrating the feed roller is further characterized as vibrating the feed roller in an axial direction.

6. A method for stress relieving fabric stored on a supply roll as set forth in claim 3 wherein the step of vibrating the feed roller is further characterized as angularly oscillating the feed roller about its axis while the feed roller is simultaneously rotated about its axis.

7. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 wherein the fabric is porous and the step of vibrating the fabric is further characterized as passing air through the porous fabric.

8. A method for stress relieving fabric stored on a supply roll as set forth in claim 7 wherein the step of vibrating payed-off fabric is further characterized as applying vacuum to an associated portion of the fabric surface to draw air through the fabric.

9. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 wherein the fabric is porous and the step of vibrating payed-off fabric is further characterized as mechanically agitating payed-off fabric within the slack region while simultaneously passing air through it.

10. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 wherein the step of vibrating payed-off fabric is further characterized as inducing vibrations within the fabric with a sonic wave generator.

11. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 including the additional step of winding the payed-off fabric onto a take-up roll after the step of vibrating payed-off fabric and controlling the take-up roll to wind the fabric thereon in a substantially unstressed condition.

12. A method for stress relieving the fabric as set forth in claim 1 including the additional step of spreading payed-off fabric onto a working surface.

1 3. A method for stress relieving fabric as set forth in claim 12 wherein the step of vibrating payed-off fabric is performed before the step of spreading payed-off fabric.

14. A method for stress relieving fabric stored on a supply roll as set forth in either claim 12 or claim 1 3 wherein the step of spreading payed-off fabric is further characterized as spreading payedoff fabric onto the working surface at a linear rate equal to the linear rate at which the fabric is being payed-off the supply roll.

1 5. A method for stress relieving fabric as set forth in claim 12 wherein the step of vibrating payed-off fabric is further characterized as vibrating the working surface with payed-off fabric spread thereon.

1 6. A method for stress relieving fabric as set forth in claim 1 5 wherein the step of vibrating payed-off fabric is further characterized as passing air through payed-off fabric.

1 7. A method for stress relieving fabric as set forth in claim 1 6 wherein the step of passing air through payed-off fabric is further characterized as drawing a vacuum on the surface of payed-off fabric engaged with the working surface.

1 8. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 wherein the step of controlling the pay-off fabric is further characterized as maintaining a free hanging loop or payed-off fabric and the step of vibrating payedoff fabric is further characterized as vibrating payed-off fabric in the region of the loop.

19. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 including the additional step of heating payed-off fabric within the slack region.

20. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 including the additional step of controlling humidity in the slack region of payed-off fabric.

21. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 wherein the step of vibrating payed-off fabric is further characterized as driving payed-off fabric at its resonant frequency by energy from an adjacent system vibrating at the same frequency.

22. A method for stress relieving fabric stored on a supply roll as set forth in claim 21 wherein the step of vibrating payed-off fabric is further characterized as driving payed-off fabric with an acoustic wave generator.

23. Apparatus for stress relieving fabric stored on a supply roll and comprising means for payingoff fabric from the supply roll, means for controlling said payed-off fabric to maintain a slack region of payed-off fabric, and means for vibrating payed-off fabric within said slack region.

24. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 23 wherein said vibrating means comprises a vibrating system proximate said slack region of payed-off fabric for causing payed-off fabric in said slack region to vibrate sympathetically at its resonant frequency.

25. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 24 wherein said vibrating means comprises an acoustic wave generator.

26. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 25 wherein said apparatus includes a chamber and said slack region and said acoustic wave generator are disposed within said chamber.

27. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 23 wherein said apparatus includes means for controlling humidity within said slack region of payed-off fabric.

28. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 23 wherein said apparatus includes means for heating payedoff fabric within said slack region.

29. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 23 wherein the fabric is porous and said vibrating means includes means for passing air through payed-off fabric within said slack region.

30. Apparatus for stress relieving fabric substantially as described herein with reference to Figs. 1 and 2 of the accompanying drawings or Figs. 1 and 2 as modified by Fig. 3 or Fig. 4 or Fig.

5 of the accompanying drawings.

30. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 23 wherein said apparatus includes a spreader table having a working surface and carriage means supported for reciprocal movement relative to said working surface for spreading payed-off fabric onto said working surface.

31. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 30 wherein said paying-off means and said controlling means are supported on said carriage means and said controlling means comprises said vibrating means.

32. Apparatus for stress relieving fabric stored on a supply roll as set forth in any one of claims 23, 30 or 31 wherein said controlling means comprises at least one feed roller engaged by the fabric and said vibrating means comprises means for vibrating said one feed roller.

33. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 30 wherein said vibrating means comprises said working surface.

34. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 30 wherein said vibrating means comprises a plate defining said working surface and means for vibrating said plate.

35. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 34 wherein said plate comprises a perforated plate and said vibrating means includes means for moving air through said plate.

36. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 35 wherein said means for moving air through said plate comprises means for producing a vacuum adjacent an associated surface of said perforated plate.

37. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 23 wherein said apparatus includes take-up means for winding payed-off fabric onto a take-up roll and means for controlling said take-up means to wind said payed-off fabric onto said take-up roll in a substantially non-stressed condition.

38. A method for stress relieving fabric substantially as described herein with reference to the accompanying drawings.

39. Fabric treated by a method according to any one of claims 1 to 22 and 38.

40. Apparatus for stress relieving fabric substantially as described herein with reference to Figs. 1 and 2 of the accompanying drawings or Figs. 1 and 2 as modified by Fig. 3 or Fig. 4 or Fig.

5 of the accompanying drawings.

New claims or amendments to claims filed on 16 Sept '82.

Superseded claims ALL New or amended claims:

1. A method for stress relieving fabric stored on a supply roll and comprising the steps of payingoff fabric from the supply roll, advancing the payed-off fabric in engagement with a feed roller at a linear rate substantially equal to the linear rate at which the fabric is payed-off the supply roll, maintaining a free hanging loop of advancing fabric defining a slack region of the fabric, and vibrating the feed roller to vibrate the payed-off fabric within its slack region.

2. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 wherein the step of vibrating the feed roller is further characterized as vibrating the feed roller in at least one radial direction.

3. A method for stress relieving fabric stored on a supply roll as set forth in either claim 1 or claim 2 wherein the step of vibrating the feed roller is further characterized as vibrating the feed roller in an axial direction.

4. A method for stress relieving fabric stored on a supply roll as set forth in claim 3 wherein the step of vibrating the feed roller is further characterized as angularly oscillating the feed roller about its axis while the feed.roller is simultaneously rotated about its axis.

5. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 wherein the fabric is porous and including the additional step of passing air through the porous fabric to vibrate the fabric in its slack region.

6. A method for stress relieving fabric stored on a supply roll as set forth in claim 5 wherein the step of passing air through the porous fabric is further characterized as applying vacuum to an associated portion of the fabric surface to draw air through the fabric.

7. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 including the additional step of inducing vibrations within the fabric with a sonic wave generator.

8. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 including the additional step of winding the payed-off fabric onto a take-up roll after it has been vibrated and controlling the take-up roll to wind the fabric thereon in a substantially unstressed condition.

9. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 including the additional step of controlling humidity in the slack region of payed-off fabric.

1 0. A method for stress relieving fabric stored on a supply roll as set forth in claim 1 including the additional step of vibrating payed-off fabric at its resonant frequency by energy from an adjacent system vibrating at the same frequency.

11. A method for stress relieving fabric stored on a supply roll as set forth in claim 10 wherein the step of vibrating payed-off fabric at its resonant frequency is further characterized as driving payed-off fabric with an acoustic wave generator.

1 2. A method for stress relieving fabric stored on a supply roll and comprising the steps of paying-off fabric from the supply roll, controlling the pay-off to maintain a slack region of the payed-off fabric, and driving the payed-off fabric at its resonant frequency by energy from an adjacent system vibrating at the same frequency.

1 3. A method for stress relieving fabric stored on a supply roll as set forth in claim 12 wherein the step of driving the payed-off fabric is further characterized as driving the payed-off fabric with an acoustic wave generator.

14. Apparatus for stress relieving fabric stored on a supply roll and comprising means for payingoff fabric from the supply roll, means for controlling said payec(-off fabric to maintain a slack region of payed-off fabric, and means for vibrating payed-off fabric within said slack region including a vibrating system proximate said slack region of payed-off fabric for causing payed-off fabric in said slack region to vibrate sympathetically at its resonant frequency.

1 5. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 14 wherein said vibrating means comprises an acoustic wave generator.

1 6. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 1 5 wherein said apparatus includes a chamber and said slack region and said acoustic wave generator are disposed within said chamber.

1 7. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 1 4 wherein said apparatus includes means for controlling humidity within said slack region of payed-off fabric.

1 8. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 14 wherein said apparatus includes means for heating payedoff fabric within said slack region.

1 9. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 14 wherein the fabric is porous and said vibrating means includes means for passing air through payed-off fabric within said slack region.

20. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 14 wherein said apparatus includes a spreader table having a working surface and carriage means supported for reciprocal movement relative to said working surface for spreading payed-off fabric onto said working surface.

21. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 20 wherein said paying-off means and said controlling means are supported on said carriage means and said controlling means comprises said vibrating means.

22. Apparatus for stress relieving fabric stored on a supply roll as set forth in any one of claims 14, 20 or 21 where-in said controlling means comprises at least one feed roller engaged by the fabric and said vibrating means comprises means for vibrating said one feed roller.

23. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 20 wherein said vibrating means comprises said working surface.

24. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 20 wherein said vibrating means comprises a plate defining said working surface and means for vibrating said plate.

25. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 24 wherein said plate comprises a perforated plate and said vibrating means includes means for moving air through said plate.

26. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 25 wherein said means for moving air through said perforated plate comprises means for producing a vacuum adjacent an associated surface of said perforated plate.

27. Apparatus for stress relieving fabric stored on a supply roll as set forth in claim 14 wherein said apparatus includes take-up means for winding payed-off fabric onto a take-up roll and means for controlling said take-up means to wind said payed-off fabric onto said take-up roll in a substantially non-stressed condition.

28. A method for stress relieving fabric substantially as described herein with reference to the accompanying drawings.

29. Fabric treated by a method according to any one of claims 1 to 12 and 28.