Method For Web Guiding Of Carpet Material

Abstract

A method for guiding a moving web material such as carpet or the like which has continuous longitudinal strands woven in parallel disposition, and which utilizes an invisible dye marker which is not readily apparent to normal viewing of the material after guiding and performance through certain processing stages. The method consists in applying selected luminescent dye marking materials to a selected thread or yarns during production of the web material and then utilizing line guide illumination and sensing responsive to selected luminescence to derive positioning signals which are then utilized through suitable control means to continually maintain lateral web position of the moving web material for trimming, rolling, etc. operations.

Description

The invention relates generally to web guiding practices and, more particularly, but not by way of limitation, it relates to an improved method for web marking and guiding of continuous material woven with plural longitudinal thread or yarn.

The prior art includes many and varied types of web guiding apparatus for carrying out the guidance function utilizing either the line guide or edge guide approach, and such equipment may perform guidance in diverse cloth, paper and/or plastic processing situations. Prior art attempts at guidance of such as carpet material has been difficult since generally relied upon sensing techniques are seriously hampered by the uneven border and texture of the material itself. That is, due to the method of manufacture of carpet and the like, wherein the carpet backing may have irregular edges variably disposed outward from the tufting or weaving, conventional guidance practices encounter various shortcomings due to materials reflectivity, edge irregularity, thickness and bulk of material, and other intrinsic properties inherent with carpet and the like at the particular stage of manufacture.

The present invention contemplates a method for web guiding wherein a normally invisible substance included in carpet tufting is made to luminesce for detection by suitable line guide and web positioning mechanism. In a more limited aspect, the invention consists of placing such invisible dye marker capable of fluorescence or phosphorescence on a selected yarn, thread or position along the web of carpet through integral weaving of the marking material; thereafter, the marker is stimulated and made to emit light whereupon the web can be moved and properly positioned with line guide apparatus sensitive to the emitted light radiation of the dye marker to provide a lateral alignment indication which is then applied to control suitable web positioning mechanism, thereby to maintain continual lateral positioning of the moving web through whatever the processing, printing, trimming or other such stages being performed.

Therefore, it is an object of the present invention to provide a novel method for tracking and guidance of a moving web of material woven with plural longitudinal yarns.

It is also an object of the invention to provide such a device for web guidance of carpet which enables edge-trimming of finished material with reduced wastage.

Finally, it is an object of the present invention to provide a web tracking method which enables line guiding of carpet having diverse patterns, textures, designs, etc; without reliance on edge uniformity.

Other objects and advantages of the invention will be evident from the following detailed description when read in conjunction with the accompanying drawings which illustrate the invention.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a functional block diagram illustrating the method of the invention;

FIG. 2 is a flow diagram showing steps performed in carrying out the novel process;

FIG. 3 is a vertical sectional side view of one form of line guide sensing head which is suitable for carrying out the method of the invention;

FIG. 4 is a vertical section taken transversely through the middle of the line guide sensing head as shown in FIG. 3; and

FIG. 5 illustrates a light mask which may be employed in the sensing head of FIGS. 3 and 4.

DETAILED DESCRIPTION OF THE INVENTION

The method of the present invention deals with structure and practice for maintaining moving lengths of longitudinally woven or tufted web material in linear alignment. Thus, as shown in FIG. 1, the material 10, made up of yarns or tufting 12 and backing material 14 is maintained in longitudinal alignment through continual positioning by a suitable form of web positioning mechanism 16. The web positioning mechanism 16 receives control input from a control unit 18 which is energized in accordance with input from a line sensor 20 responsive to a registry line 22. The registry line or marker yarn 22, shown as a triangular character, is actually formed as an invisible line which can be made to fluoresce or emanate such characteristic radiation for sensing by line sensor 20, as will be further described in detail.

The registry line 22 may be effected by any of various solutions or substances applied to the web material at a desired lateral position so that it is invisible under normal viewing but can be made to fluoresce or phosphoresce for sensing about the position. The invisible radiating stripe of treated yarn or such can be formed using various solutions, e.g. zinc sulphide, selected organic and inorganic salts, and other materials to be described. Also, a phosphorescent pigment known as Shannon Glow Pigment No. B-320 is commercially available from Shannon Luminous Materials Company of Los Angeles, Calif. This pigment is capable of residual glow for several hours after exposure to light and may find various specialized marking uses.

There are many materials, organic and inorganic, which are capable of luminescing under selected stimuli to produce radiation suitable for line sensing purposes. Such luminescence may occur by either fluorescence, or phosphorescence. That is, initial persistence of luminescent emission following the removal of excitation will depend upon the lifetime of the excited state. This initial emission decays exponentially and is known as fluorescence. In many instances, there is also an additional component of afterglow which decays more slowly. This component is known as phosphorescence and it too may be utilized in line sensing applications.

The desirable luminescing properties are present in many organic and inorganic materials which may exist in suitable form for application as linear markers. Generally, good organic materials may be the aromatic molecules related to dyes such as the sodium salt of fluorescein in dilute aqueous solution, Terphenyl in Xylene, Anthracene in Napthalene, Rhodamine and many other solutions and organic crystal gels and suspensions. There are also numerous inorganic substances or phosphors having the desirable applications and marking properties, e.g. certain doped alkali halides, ZnS, and various silicates and phosphates properly suspended in fluid form or as might be utilized in dust form.

The radiative material is applied to a selected portion or position of the moving web to provide the desired registry line for guide sensing. Thus, as shown in the flow diagram of FIG. 2, a selected dye marking substance 24 may be applied to dye a specific yarn in yarn supply 26 prior to material production 28 and previous to any additional web processing 30. Thus, following arrow 32, the dye marking substance 24 is contained in a selected skein of input yarn, i.e. the yarn forming a selected row of pile or tufting along backing 14, e.g. the antepenultimate warp yarn on a selected side. If desired, the dye marking substance 24 can be washed or otherwise cleaned out of the finished material after all processing is completed; however, it may not be required since with some marker substances the fluorescent quality does not usually persist for more than a few hours.

The inclusion of such as a marker yarn in initial weaving has also been recognized to be valuable in production of tire cord. In this application the marker yarn is generally woven along a lateral mid-point of the tire cord web. In any event, the dye marking substance should serve its function to enable web guiding through various stages of material coloring, printing, trimming through final roll-up, and in some cases the luminescing or fluorescing property will dissipate to leave no visible trace of the registry marker on the finished product.

One form of the line guide sensing head which is suitable for use in the present invisible line method is illustrated in FIGS. 3 and 4. A sensing head 40 is disposed in close viewing relationship to material 10 as supported to pass over a platen 42. The platen 42 is deemed desirable to maintain the plane of material 10 constant as changes in plane can cause variations in output of the sensing head 40.

Sensing head 40 consists of a housing 44 which is formed in generally rectangular shape to contain a pair of fluorescence stimulation light sources 46 and 48 as disposed on opposite sides of the interior of housing 44, and an optical unit 50 is affixed centrally therebetween. The fluorescing light sources 46 and 48 are suitably supported in electrical contacting sockets 52 as disposed at opposite ends of housing 44. A 110 volt line power input (not specifically shown) is applied in conventional manner to energize each of the light sources 46 and 48.

The fluorescing elements or light sources 46 and 48 may be any of various types which are capable of irradiating the invisible line to cause emanation of the fluorescent radiation. One form of bulb which gives good results is the General Electric type No. F4T5-BLB, a mercury arc type of lamp which is coated to block white or visible light while passing largely black light for irradiation purposes.

The optical unit 50 is centrally secured by means of fasteners 54 within the housing 44 at a central location between light sources 46 and 48. The optical unit 50 contains a cylindrical lens 56 as secured across the bottom in viewing relationship to a marker yarn registry line 22 along the edge of material 10. A mask 58 may be disposed immediately above lens 56 to define apertures 60 and 62 admitting fluorescing light radiation to respective photo cells 64 and 66. The photo cells 64 and 66 may be conventional photo cells, e.g. photoconductors of selected sensitivity, and the electrical output is provided through respective leads 68 and 70 passing through feed-through grommet 72 for external connection to a suitable control unit such as control unit 18 (FIG. 1).

The aperture mask 58 is formed with two apertures 60 and 62 which are triangular in shape and arranged in oppositely-disposed orientation. Thus, when aperture mask 58 is aligned along the marker yarn registry line 22, any sideways movement of the line relative to aperture mask 58 will cause oppositely varying light characteristics as viewed through each of apertures 60 and 62. This form of edge or line guide detection utilizing such as aperture mask 58 is fully taught in U.S. Pat. No. 3,431,425 entitled "System for Photoelectric Control of Moving Webs," issued on Mar. 4, 1969 in the name of Brown et al. and assigned to the present assignee. The particular control unit and web positioning mechanism as disclosed in the above-identified patent may also find particular use in carrying out the method of the present invention.

In performing the method with a device such as that of sensing head 40, it is important that the housing 44 be positioned down reasonably close to the upper surface of the yarn or tufting 12. It has been found in practice that placement of the cylindrical lens 56 no more than one-quarter inch above yarn 12 will provide good tracking operation with delivery of sufficient fluorescence generating illumination to cause emanation of fluorescent light passing upward through cylindrical lens 56 to each of the photo cells 64 and 66.

Thus, in the case of web guiding of material 10, the marker yarn is woven into the web at one or more places, depending upon requirements. The marked web is then moved continuously along its processing route with the edge or such other portion having the marker yarn registry line 22 passing beneath the optical unit 50. The energized light sources 46 and 48 then irradiate the immediate portion of material 10 such that the marker yarn registry line 22 luminesces in detectable manner. That is, emanation of short-wavelength light, such as ultra violet, excites electrons to an upper-energy state to cause fluorescence which is then detectable by the photo cells 64 and 66. These photo cells are preferably chosen from photo-conductive or photo-voltaic elements which exhibit specific sensitivity at the luminescing light energy wavelengths.

The fluorescent light emanating from marker yarn registry line 22 is thus collected through cylindrical lens 56 and directed to greater concentration upon each of photo cells 64 and 66. These photo cells 64 and 66 are able to generate a differential signal output relative to lateral variations of registry line 22 due to the aperture mask 58. That is, the triangular mask openings 60 and 62 are oppositely disposed to cause inversely varying signal generation characteristics in response to side-wise movement of registry line 22. Such signal outputs from photo cells 64 and 66 are then applied in conventional manner to control unit 18 so that the necessary control signal output is applied to web position mechanism 16 to re-position the material 10, i.e. to bring the registry line 22 back to its center or nulling position.

It should be understood that while specific reference is made to fluorescent illumination and properties of suitable fluorescing dye marker, there are many other materials and detectors which might gain advantage of the luminescing property, i.e. either fluorescing or phosphorescing of the material, to emit characteristic radiation. Thus, black light irradiation of register line 22 with emission of fluorescent light for detection in sensor photo cells 64 and 66 is but one application which is suitable for the line sensing function. It may well be that the dye marking substance applied to form marker yarn register line 22 is a substance capable of scintillating in the presence of such as gamma or beta ray radiation whereupon phosphorescent illumination is emanating for sensing detection purposes.

No matter what the type of dye marker and detector used, the method enables an essentially invisible marker yarn register line 22 to be placed or integrally woven along a specific area or line on a web of carpet material, tire cord or such in non-destructive manner. Thereafter, the carpet or such web material can be processed through various printing and trimming stages utilizing the marker yarn registry line 22.

One of the very valuable attributes with regard to carpet material is the use of the invisibly dyed marker yarn as a register line 22 in the final processing stages, i.e. the carpet trimming operation. It is inherent in carpet manufacture that the backing 14 have relatively rough edge dimensions while the pile or weave tuft material 12 may be maintained in its true, linear alignment. The backing material 14 is so irregular that carpet is generally trimmed by cutting a given, large dimension from the average edge registry in order that an even edge will be finally produced. The necessity for trimming at an average distance along the edge of the carpet backing results in great wastage of the carpet material, and although various sensing devices have been tried, this wasteful edge trimming practice is prevalent in the carpet manufacturing field.

Institution of the present method has enabled carpet to be trimmed by guiding the trimming mechanism relative to the invisible marker yarn registry line 22. It would be possible to place invisible marker on the extreme outside pile or weave of the fabric; however, in the interest of allowing some safety margin, and to give a better trim, it is the general practice to weave the invisible dye marker yarn as the second or third row of pile or tufting, and subsequently to scan the marker yarn in accordance with the present method to provide relative position guidance to the trimming mechanism.

The foregoing discloses a novel method for web guiding of woven materials having particular characteristics which hamper or lessen the accommodation of established techniques and systems. The present method is particularly attractive due to the fact that the alignment mark can be woven integrally with the web material with no outward visible appearance, and even the fluorescing or phosphorescing property can be removed or may soon loose its luminescent strength so that, in effect, the method can be employed with no after affects of visible nature. The method is performed with variations of existing equipment such that it is essentially a low cost operation, especially when considering the possibilities as to reduced wastage in processing and final trimming of certain carpet materials.

Changes may be made in the combination and arrangement of steps and elements as heretofore set forth in the specification and shown in the drawings; it being understood that changes may be made in the embodiments disclosed without departing from the spirit and scope of the invention.

Claims

What is claimed is:

1. A method for web-guiding of a moving web of carpet material for trimming and rolling operations, said web of carpet material having continuous warp components and utilizing invisible dye marking substance having particular luminescence characteristics, comprising the steps of: weaving a selected warp yarn as one of said warp components along said web of carpet material as a register point at a pre-selected transverse position of the web proximate the outer edge warp component said selected warp yarn carrying said invisible dye marking substance; irradiating said moving web proximate said transverse position to cause predetermined luminescence of said dye marking substance; detecting transverse positional variations in said luminescence indicative of transverse positional variations of said moving web; generating a control function proportional to said detected transverse positional variations in said luminescence; re-positioning said moving web in an amount proportional to said control function to counteract said transverse positional variations until said invisible dye marking substance is at said pre-selected transverse position; and processing including edge trimming of said moving web of carpet material in order to form a carpet edge while maintaining minimal wastage of edge fabric of said carpet material and thus eliminating the need for overcutting with a selected safety margin.

2. A method as set forth in claim 1 which is further characterized in that: said invisible dye marking substance is fluorescent, and said irradiation is black light to generate detectable light emanations.

3. A method as set forth in claim 2 which is further characterized in that: said fluorescent substance is in liquid form and is contained throughout a selected yarn of said moving web continuously therealong.

4. A method as set forth in claim 1 which is further characterized in that: said invisible dye marking substance is a liquid substance capable of emitting phosphorescent light radiation in response to characteristic irradiation.