GB2119713A - Applying patterns to webs - Google Patents

Abstract

A method of manufacturing a web having a multicoloured pattern, wherein an array of applicators for each colour apply strips of colour of varying length but of modular width. Each applicator covers a modular width of the web, and the applicators together cover the width of substantially the entire web. The applicators are activated individually there being thus obtained a pattern which can be varied at will. The invention also relates to colour- applying apparatus including several applicators having modular widths, e.g. in the form of a colour roll on which colour is spread out with a scraper, together with a series of individually operable roll portions, with which portions of the web can be pressed against the colour roll or lowered out of engagement with said roll; or a screen roller similarly arranged; or an array of slot-like nozzles individually operable.

Description

SPECIFICATION A method of manufacturing a web having a mulicoloured pattern, and colour-applying apparatus for applying colours to a passing web A method of manufacturing a web having a multicoloured pattern, parts of the web being provided with layers which may have different colours. The invention also relates to a colourapplying apparatus for applying such layers to a passing web.

The invention can be used for manufacturing webs provided with camouflage patterns, but other types of pattern may also be produced, e.g.

for signs, tents, truck tarpaulins and generally where it is desired to apply coloured patterns to webs where the patterns are not simple.

In applying coloured patterns to fabrics, sheets, tarpaulins and the like, it has so far been customary to use such methods as stencils or templates and spraying colour, silk-screen printing or even painting-on by hand. Both flat and rotating surfaces have been used, although these have the disadvantages that a limited pattern repeat is obtained. A method of increasing the pattern repeat may be read from our US Patent 3 967 026, but the disadvantage with a limited pattern repeat remains even so, and it is therefore one of the objects of the present invention to achieve a possibility of extended pattern repeat and greater freedom with regard to the application of colour patterns on long web-like materials.

This is achieved in accordance with the invention in that with a method of the kind mentioned in the introduction a web rolled up on a roller is pulled past a colour-applying apparatus comprising an array of applicators for each colour to be incorporated in the pattern; in that the applicators are operable between active and inactive positions; in that each of the applicators covers a limited width of the web; in that as the web is drawn past it, the individually operable applicator appiies a strip of coloured plastics just as wide as the limited width and just as long as the length of the web which has passed the applicator during the activation time of the latter; in that each array for one and the same colour commonly extends substantially over the whole width of the web, the pattern being obtained by the different applicators being intermittently activated for applying the coloured plastics coating over the limited width and with a length corresponding to the respective time of activation.

It is thus possible to provide a kind of colour grid with a modularly determined grid pattern which is entirely controllable.

According to a preferred embodiment, particularly utilizable for providing webs intended for masking purposes, the plastics layer grid is laid on a carrier in the form of coloured plastisols, for example, upon which there is laid in a manner known per se, e.g. using a scraper blade, a further, fully covering plastics layer. After curing, the combined plastics layer thus formed is stripped off as a self-supporting web from the carrier to be a flat-lacquered carrier fabric, resulting in that the stripped-off web will have a mat surface on the pattern side, which is important for military masking purposes.

By reason of the great freedom with respect to pattern, the invention is particularly suitable for masking purposes, and can achieve quite surprising effects in this respect.

The modern, computer-aided picture analysis used militarily for aerial and satellite pictures taken for reconnaissance purposes is based, i.a. on pattern recognition which attempts to see entireties, although the picture has low resolution.

As an example of this, where the eye more or less functions as a picture-analyzing computer, Fig 1 may be considered which illustrates an eye (in black and white) with a finer and finer grid vision from A to B. If this picture is observed by the eye from a distance from 5-6 meters, a different images appear indistinguishable from each other.

It is thus possible to make a grid pattern with large squares which seems entirely arbitrary and without detail close to, but from a distance may be recognized as a definite object. It is also possible to create a pattern which dissolves well into nature with all its variations. The problem is then that nature varies, and it it obvious that a pattern which harmonizes well with Swedish forest terrain is hardly suitable in the desert or in urban snowcovered terrain. Furthermore, there are large variations in each type of terrain, not least in respect of seasonal variations. In the production of camouflage up to now it has been necessary for the sake of variation to work with material stamped out, e.g. in hexagonal shapes, from different materials which have their individual colours, the pieces being laid out manually on supporting nets in suitable patterns.For example, with Swedish standard nets hexagons with a diagonal dimension 44 cm have been used in three different colours with the proportions of 40% dark-green, 50% light-green and 10% brown, but with the brown and light-green colours having the same brightness, whereby these run together into a single colour when observed by the eye at a distance. There is thus obtained an appropriately detailed close-version pattern (distance about 200 ms) and similarly a good remote distance pattern (distance about 2000 m).

Although all the masking nets in a delivery are seldom made up to be exactly the same, particularly patterns easily occur due to the minor number of modifications which a computer can be programmed to recognize, making it important to provide great richness in variation and a repeat length substantially longer than that of the individual masking net. This can be provided in accordance with the invention.

Theoretical and practical investigations which we have carried out have shown that in practice it is suitable for masking purposes to work with a least pattern element in the form of a square with a side of 20 cm (modular dimension 20 cm). The patterns can then be made effective for both close and long distances with appropriately accentuated contrasts for short distance and sufficient contrast for long reconnaissance distances at the same time. Such a system can also be put in order technically for computer-controlled manufacturing methods.

A suitable method of obtaining a pattern is to use an aerial photograph of nature, which is "squared-up" with adequately large spaces between the lines of the grid and in three different colours, for example, suitable for illustrating the type of terrain in question. The corresponding operation can be carried out on a picture of a "quickly masked" military target, enemy reconnaissance thus being lured to believe that masking laid out is a military target.

The invention also relates to colour-applying apparatus for applying plastic layers to a passing web.

Spotwise or gridwise application of coloured plastics layers to webs and fabrics has been carried out up to now with the aid of flat stencils, silk-screen and the like, or rotating, patterned rolls, leading in both cases to limited pattern repeat and flexibility, for obvious reasons. These disadvantages are avoided in accordance with the invention by a kind of series printing, where what is printed continuously and under control varies as the web passes by, in that the colour-applying includes a plurality of applicators each arranged for coating strips of a web in the travelling direction of the web, said strips together covering the width of the passing web, and where the applicators are selectively and individually operable to an active state for colour-application or to an inactive state for the exclusion of colour-application.

In accordance with a presently preferred embodiment colour applicators are used, each including a nozzle with a slit arranged transversely travelling direction of the web, an input for the supply of plastics composition under pressure, a signal-operated valve arranged between the input and the slit for feeding the plastics composition out through the slit, and means for altering the distance between web and slit for taking the slit close to the web for application of the plastics composition. The applicator thus functions similar to a roller peculiar scraper blade continuously supplied with the plastics composition.

It is also possible to use a roller-shaped applicator, either one in which the composition is applied on its outside and smoothed out with a scraper blade (gravure roll or counter-rotation roll) or a silk-screen printing roll. The applicators can be brought into their active positions against the web either by being moved themselves towards the web or by the web being moved towards them with the aid of holding-up means, which may be holding-up rolls but may also be such as are non rotating and which have low friction so that the web can glide over them.

For avoiding any interference between applicators disposed mutually adjacent, it may be suitable to place them zig-zag, in different rows arranged transverse the longitudinal direction of the web, and such that two sequential applicators, as seen in the transverse direction, are always disposed in different rows.

The invention will now be described in conjunction with the drawings, which illustrate embodiments of the invention.

Fig 1, which has already been described, illustrates an example of picture analysis with different grid densities. Fig 2 illustrates an example of a suitable masking pattern intended for Swedish summer terrain. Fig 3 schematically illustrates a paste composition applicator for applying two colours. Figs 4 A-C illustrate a special paste composition applicator in cross section, Fig 4A illustrating the principle for the paste application itself, while Figs 4B and C illustrate raising and lowering of the applicator. Fig 5 illustrates a mounting arrangement for a paste composition applicator, e.g. of the type illustrated in Figs 4 A-C. Fig 6 illustrates the disposition of the application in the form of strips adjacent each other, the applications being applied zig-zag.Fig 7 illustrates the principle of applying colour with the aid of a so-called gravure roll. Fig 8 illustrates colour application with the aid of a counterrotation roll. Fig 9 illustrates an application roll with the roll shouldered. Figs 10 and 11 are sections through the roll in Fig 9 along the sections X-X and Xl-Xl, respectively. Fig 12 illustrates the arrangement of movable holding-up rolls for a row according to Figs 9-11. Fig 13 is a perspective view of an applying roll with uniform spread, coacting with a divided holding-up roll, the parts of which are individually raisable and lowerable. Fig 14 is a schematic side view of the roll in Fig 13. Figs 1 5 and 16 illustrate the construction of a silk-screen roll operable for moving.Fig 17 illustrates an example of a plant with nine separate application roll units with associated means for thermo-setting.

Fig 2 illustrates an example of a masking pattern of the kind which can be produced in accordance with the invention. In this Figure there is schematically illustrated a portion of a web conceived as being modularly divided into striplike surface portions A-I. With the aid of special, individually controllable applicators, one for each strip A--l and one for each different colour, there have been applied three different colours L (lightgreen, M (dark-green) and BR (brown). in accordance with the invention and seen as in the Figure, the boundaries between different colours must be delimited from each other by vertical lines coinciding with the boundaries between the strips A-I, while the horizontal boundaries are at right angles to the boundary lines just mentioned. In spite of this limitation it is possible to obtain a pattern which is rather rich in detail. It is a usual desire that this pattern will imitate some kind of nature, but it is also possible to allow the pattern to imitate some object made by man, or even prepare an advertisement sign, decorated tent or tarpaulin etc.

The principle for applying two different colours on a crossing web 1 travelling according to the arrow 2 is illustrated in Fig 3. Two sets of applicators 3 and 4 with a colour each are each mounted in a row transverse the travelling direction 2 of the web.

During the nearest passed period of time, the applicator 3' has been activated and has generated a coloured strip 3". During a somewhat shorter time the applicator 4' in the row 4 has been activated and has thus covered the web area 4" with another colour. It is clear that with this principle and by activating the different applicators in the rows a two.colour pattern of the same type as the pattern in Fig 2 is enabled.

Figs 4 A-C illustrate an embodiment of an applicator of a type which may be used according to Fig 3. The cross-section of a nozzle is illustrated in Fig 4A. There is a channel system 6 in the nozzle, fed with a paste composition in a manner not more closely illustrated, the composition preferably being of the plastisol type, which is supplied under control and pressure and is fed out through the slit 7 towards the passing web 1. The paste is smoothed out with the aid of the lip 8, the past obtaining a finished thickness a due to the dynamic factors, this thickness being somewhat greater than the distance b between the web 1 and the lip 8.For obtaining a clear beginning and end of the coloured areas, seen in a direction at right angles to the plane of the paper, it is suitable to raise the lower the jet 5 in time with applying pressure for the colour application, since there is otherwise the risk of paste being fed up even after the colour has ceased to be printed. (It is alternatively possible to allow the paste to be sucked back again to a small extent by activating an unillustrated piston when the colour-feeding pressure is removed). A practical container enabling pneumatic raising and lowering is illustrated in Figs 4B and 4C.The nozzle 5 not shown in detail in these Figures is disposed between the flat legs of a forked structure 9, where a return spring is arranged on one side and on the other there is an O-ring accommodated in a groove, within the confines of which there is a compressed air canal, coupled via a solenoid valve 10 to an unillustrated compressed air source. The solenoid valve has two states, one where the compressed air is allowed to pass so that the nozzle 5 will be pressed downwards against the bias of the spring 12, as in Fig 4C, and another state when the compressed air canal is vented to atmosphere, the spring 12 returning the nozzle 5 to the position illustrated in Fig 4B. Apart from its sealing function, the O-ring also has a dampening function for eliminating vibrations.

Fig 5 illustrates a method of mounting a row' of nozzles 5 on a boom 20 disposed transverse the travelling direction of the web. The fork structure 9, retaining the jet 5, has an extension in the form of a plate 9' accommodated in a clamping joint between two jaws 21 and 22, which are kept together by bolts 23, of which only one is shown.

The bolts 23 pass through the jaw 21, extension 9', jaw 22 and a retainer 24, wherein the bolt heads are accommodated. Spring means 25 is biased to keep the retainer 24 and the jaw 22 from each other, thus indirectly via the bolts 23 providing clamping force between the jaws 21 and 22 such that the fork extension 9' will be retained.

However, the jaw 22 is united with the boom 20 via a support bracket 27 with the aid of a series of bolts, whereof only the bolt 28 is shown. The retainer 24 is accommodated in a cylindrical hole in the bracket 27 and sealed at its circumference with an 0-ring 26, and the space between the retainer 24 and bracket 27 can be filled with compressed air in a manner not illustrated in the Figure. It will be seen from the Figure that if this takes place, the retainer 24 will be pressed against the jaw 22 attached to the bracket 27 by the action of the bias of the spring means 25 such that the clamping force between the jaws 21 and 22 exerted by the fork extension 9' via the bolts 23 can be decreased or eliminated entirely.The bolts 23 are taken through rather large holes, enabling the fork extension 9' to be moved to its position for adjusting the height (and slope in a plane at right angles to the paper). It is possible to provide this equipment with a compressed air supply either individually, or for each nozzle 5 on the boom 20 or for all the nozzles 5 simultaneously.

The applicator nozzles 5 described so far can be mounted individually movable side by side without any particular problems, and such that two nozzles mounted side by side provide a rather invisible colour junction at the boundary of the areas of action, and all applicators working with the same colour can therefore be mounted on a single boom. This is not the case with some types of applicator, however, and here they may be mounted on two different booms and in alternating positions as indicated in Fig 6.

Instead of using the slit applicators as described, it is also possible to make the application by means of rollers. Figs 7 and 8 shows the principle for two embodiments of this method, where paste is brought onto a roller 30 or 30', which applies paste on to a web 1, supported by a counter-roller 31. The paste 33 is applied in an even layer by scraping with a doctor blade 32.

In Fig 7, the colour roller 30 is a so-called gravure roller, generally provided with some kind of pasteaccepting gravure pattern, and the roller 30 rotates in the same direction as the web passes. In Fig 8, however, the colour roller is brought to rotate contrary to the passing web 1.

In both cases, according to the invention, the object is to obtain paste-application in band form.

It is possible to arrange separate applicators, each having a width corresponding to the desired modular width (e.g. 20 cm), and as a rule, it is then necessary to arrange the roller devices in alternating positions as indicated in Fig 6. In order to reduce the number of rolls for each colour to two it may be suitable to proceed in the way apparent from Figs 9, 10 and 11. Both rolls for the same colour are then disposed such that they are provided with diameter reductions 35 alternating with active cylinder portions. which are just as long as the portions with reduced diameter, a portion of reduced diameter on one roll corresponding to an active portion on the other according to the principle illustrated in Fig 6.

In this case the same scraper blade 32" may be used, which has its edges along two lines for applying according to Fig 10 a suitable paste thickness along the active part and scraping away substantially all the paste on the reduced parts, in a manner apparent from Fig 11.

In order to control what portions on the passing web are to be provided with paste and which are to be without paste separate holding-up rolls 31" are arranged as illustrated schematically in Fig 12, these rolls being individually raisable and lowerable, e.g. by their being mounted in forks which are raisable and lowerable by means of compressed air cylinders. When such a short roll is iowered, the web 1 at this point will be free from the paste on the upper roll.

It is also possible to arrange a series of holdingup rolls 31 disposed mutually adjacent and individually raisable and lowerable, with their axes coinciding, in this case it being sufficient with a single colour roll 30 which can be counter-rotating or rotating in the same direction. A plan view illustrates schematically in Fig 14 a series of such rolls, while Fig 13 illustrates the colour roll and holding-up rolls in perspective. The short rolls are hollow and function on a common boom (not shown), provided with exterior mounting means which are raisable and lowerable and against which the hollow rolls glide on their internally directed surfaces. It is also possible to allow the movable roll portions lying adjacent each other to rest against raisable and lowerable bearing rockers against which the roll portions glide.

Instead of rolls taking up paste on their outsides, so-called silk-screen rolls may be used.

This kind of roll functions such that paste composition is arranged on the inside of a cylindrical fine-mesh net and urged towards the outside of the net against which engages a web which is to be coated with colour, the paste composition being pressed out with a scraper arranged on the inside opposite the web. A cross section of such a construction is illustrated schematically in Fig 15, where the net is denoted by the numeral 43 and the scraper by 32. The screen roll 43 is rotatably mounted on a swinging arm 42 with the aid of rollers 44, 45, 46 in a manner which will be explained with reference to Fig 1-6, the arm being swingable about a fixed shaft 40 in a boom structure 40. One end of a compressed air cylinder 41 is pivotably mounted on the boom structure 40 and its other end mounted on the shaft 42' in the swinging arm 42.The roll 43 is thus raisable and lowerable.

As will be seen from Fig 16 the roll 43 is provided with rings at its ends, said rings having an inner support surface 47 and an outer support surface 48. Two rollers 45, 46 at different places along its circumference (see Fig 1 5) engage against an outer surface 48, while one roller 44 engages against an inner surface 47 of each ring.

The roller pairs 44, 45 and 46 are rotatably mounted in the swinging arm 42, which is formed with fork-like arms for mounting the roll 43 at either end. Due to the construction it is difficult to arranged the screen rollers side by side, and they must therefore be arranged on two boom structures 40 for each colour.

A plant is illustrated in Fig 17 for coating and drying a web in accordance with the inventive principles. A web is pulled from a supply roll 50 through a number of roll stands which partly serve to provide suitable tension and partly to cure and dry the web after the application of colour. At 52 there is illustrated a pair of rolls for colour application, after which the web goes into a roll stand where at least the first roll is heated, there being evacuation means 53 for evacuating the solvent thus liberated.

Although the invention can be applied in many different ways, which will be understood from the aforesaid, it is preferred to use such methods where the amount of solvent can be kept down.

Paste compositions suitable for distribution with scrapers are therefore preferred. Such colour pastes have been found very usable with the nozzle arrangement described in conjunction with Figs 4 A-C and Fig 5. These function very well when provided with raising means, and even with rather primitive trial equipment it has been found possible to obtain well defined rectangular colour patches with a web speed of 11 m/minute. A speed of 1 5 m/minute is within immediate reach at present, and a considerably greater speed is awaited after operation has been tuned up.

The webs which are to be coated are not entirely inelastic in the stretching direction, and when it is desired to lay several different coatings of colours, the problem arises of getting the joints between the fields of colour in the transverse direction of the web to be positioned with the minimum amount of overlap and without gaps. In order to provide suitable correction for the elasticity in the webs, it is therefore suitable to provide these right from the start with a periodical pattern at the edges which is monitored by photodetectors during the subsequent operations, the control of colour application for each applicator being arranged with the aid of electrical pulses from the detectors, said pulses being taken to a computer which controls the activation of the different applicators.

Claims (14)

1. A method of manufacturing a web provided with a multicoloured pattern, portions of the web being provided with coatings of different colours, characterized in that a web rolled up on a roller is pulled past a colour-applying apparatus comprising an array of applicators for each colour to be incorporated in the pattern; in that the applicators are operable between active and inactive positions; in that each of the applicators covers a limited width of the web; in that as the web is drawn past it, the individually operable applicator applies a strip of coloured plastics just as wide as the limited width and just as long as the length of web which has passed the applicator during the activation time of the latter; in that each array for one and the same colour commonly extends substantially over the whole width of the web, the pattern being obtained by the different applicators being intermittently activated for applying the coloured plastics coating over the limited width and with a length corresponding to the respective time of activation.

2. Method as claimed in Claim 1, characterized in that the coloured plastics layers which are preferably of the plastisol type, are applied with the aid of an applicator onto a carrier and cured, over this layer there being applied a further totally covering plastics layer which is also cured, subsequent to which the entirely covering plastics layer together with the coloured plastics layer being stripped off as a self-supporting web from the carrier.

3. Method as claimed in Claim 2, characterized in that the carrier is a mat carrier weave, wherebv the stripped-off self-supporting web is given a mat surface on its colour-patterned side.

4. Method as claimed in any of the preceding claims, characterized in that the different applicators are activated in accordance with a pattern resulting from a picture analysis pattern produced from a picture of nature or a picture of an object preferably for likening to an aerial photograph.

5. Colour-applying apparatus for applying colour to a passing web, characterized in that the apparatus includes a plurality of applicators each adapted for coating strip-like portions in the travelling direction of the web, said portions together covering the width of the passing web, said applicators being selectively and individually operable for application or inoperable for excluding application.

6. Colour-applying apparatus as claimed in Claim 5, characterized in that each applicator includes a nozzle with a slit arranged transverse the travelling direction of the web, an input for supplying colour paste composition under pressure, a valve operable with the aid of a signal and arranged between the input and the slit for feeding out paste through the slit, and means for changing the distance between web and slit for bringing the slit close to the web for applying the paste.

7. Apparatus as claimed in Claim 5, characterized in that the applicators have the shape of rolls and together take up substantially the whole width of the web.

8. Apparatus as claimed in Claim 7, characterized in that the applicator rolls are equipped with blades for evening out the paste on the rolls.

9. Apparatus as claimed in Claim 7, characterized in that the applicators are silkscreen printing rolls, applied with paste on their insides.

10. Apparatus as claimed in any of Claim 5-9, characterized in that the individual applicators are activatable by means for individual movement towards the passing web.

11. Apparatus as claimed in any of Claims 5-9, characterized in that the web opposite the individual applicators may be individually approached by the respective applicator.

12. Apparatus as claimed in Claim 11, characterized in that opposite the applicators and on the opposite side of the web there are arranged individual holding-up means which are movable with aid of signals.

13. Apparatus as claimed in Claim 12, characterized in that the holding-up means comprise free-rolling rolls.

14. Apparatus as claimed in any of Claims 5-13, characterized in that the applicators for one colour are disposed in at least two separate rows, so that in the transverse direction of the web two sequential applicators are always disposed in different rows.

1 5. A method of manufacturing a weg substantially as hereinbefore described.

1 6. Colour-applying apparatus as hereinbefore described with reference to and as shown in the accompanying drawings.