US3179024A - Method of and arrangement for producing crimped flat material - Google Patents

Description

April 20, 1965 P. A. MULLER 3,179,024

METHOD OF AND ARRANGEMENT FOR PRODUCING CRIMPED FLAT MATERIAL Original Filed April 18, 1955 2 Sheets-Sheet 1 I Fig.3 Fig.5 u-u- M 1N VEN TOR.

ATTORNEKS April 0,1965 P. A. MULLER 3,

METHOD OF AND ARRANGEMENT FOR PRODUCING CRIMPED FLAT MATERIAL Original Filed April '18, 1955 2 sheets-sheet 2 United States Patent "ice tion Jan. 21, 1963, Ser. No. 252,909

17 Claims. (Cl. 93-1) The present invention relates to a method of and an i 4 arrangement for producing crimped, i.e., grooved, fiat material, particularly crimped paper webs for smoke filters. This application is a division of my copending application Serial No. 841,919, filed September 2, 1959, which is a division of application Serial No. 502,016, filed April 18, 1955, now Patent No. 2,995,481, which was a continuation-in-part of my application Serial No. 447,478, filed August 3, 1954, now Patent No. 2,847,086.

Crimped papers are already known and, besides other purposes, are used to an important extent for the manufacture of filters for tobacco, particularly for cigarettes. Since, with such filters, flat webs of paper have to be shaped into cylindrical plugs, the paper used must have only a slight rigidity at least in one direction. A noncrimped web of paper would, on being compressed into a cylindrical cord, have irregular folds and randomly distributed bulges, which would lead to an irregular web cross-section with hollow spaces and unconnected ducts, that is to say, the result would be a structure completely unsuited for filtering purposes. Crimped paper, on the other hand, does not have these disadvantages and for this reason paper filter plugs are almost exclusively made with such material.

The crimping of the paper web, however, also facilitates the mechanical manufacture of such filter plugs and,

furthermore, ensures that they will have the necessary porosity.

Crimped paper has so far been produced almost exclusively by a generally known method in which an endless damp webof paper runs on to a heated cylinder, dries there-to a certain extent and is peeled off by a blunt scraper, the previously smooth paper web being upset.

of length of the final product can be stretched to three times its length and ironed out into a smooth web, that is to say, in its crimped state, it is threetimes as heavy as the smooth web.

With a web of paper crimped by this method the Y crimped folds and grooves run transverse to the direction of travel. Although crimping of the web is indispensable, the fact that it runs transverse to the web complicates both the machines for the production of filters and the process employed therefor. As the filter cord is produced by the placing together of one or several paper strips of given width, which can only be done vertically to the crimped, folds, strips of the aforesaid width must be cut off the broad crimped Webs of paper so that these strips cannot be longer than the width of the crimped web. These strips are then fed to the gathering attachment of the filter plug machine in the longitudinal direction, i.e., parallel to the crimped folds.

In order to make continuous production possible, such longitudinally crimped paper strips of limitedlengthare arranged side by side and slid continuously into the 3,179,024 Patented Apr. 20, 1965 gathering attachment. Apart from the cutting and conveying devices thus required, which work intermittently and cause an increased susceptibility to breakdowns, the small length of strip provides a number of extremely troublesome shortcomings. In order to ensure that the successive strips are properly introduced into the gathering attachment, strips wider than 4 to 5 cm. cannot be used, this, as the material required is determined by the dimensions and thickness of the filter card, makes it necessary to lay four to six crimped strips one on top of the other and to work them jointly in the gathering attachment, thus complicating the feeding apparatus still further. Since no other way of continuous manufacture has been known hitherto, extensive mechanical devices have been designed for the purpose and used in practice. It has also already been suggested to paste the separate crimped strips together by hand so as to permit continuous operation (cf. German Federal Patent No. 826,257).

Apart from this feed difficulty, however, another drawback is that the first and last filter of every crimped strip of limited length have to be considered as rejects as both may contain the junction point between successive strips. This must be avoided since with strips which are not pasted together part of the filter plug may easily drop out of the cigarette and with pasted strips the filtering effect is impaired by the pasted edge.

1 terial.

Thus there exists a need for a simple method of producing fiat material crimped in any desired direction from a smooth web of material and for an arrangement for producing an endless longitudinally crimped web of material.

The present invention relates to a method of this sort and is characterized by the fact that the smooth web of material is made yielding and is then crimped and stretched by grooving so that a unit of length of the crimped web of material is at the most equal in Weight to the same unit of length of the smooth web.

Furthermore, the invention relates to an arrangement for the abovementioned purpose. This arrangement is characterized by processing devices designed to achieve a desirable yieldingness of the smooth web of material, by members for producing grooves in the web of material with simultaneous stretching of the latter, the grooves running approximately parallel to the longitudinal direction of the web of material, and by a drier for the thus crimped web of material.

The web of filtering material produced on the arrangement and by the method according to the invention is characterized by the fact that it is an' endless web with a longitudinal structure parallel to its direction of travel, consisting of alternately thicker and less thickstrip ma- A typical embodiment of the invention will now be described in detail in conjunction with FIGS. 1 to-13 of the attached drawing in which:

FIGS. 1 and 2 are a vertical and horizontal projection respectively of a typical embodiment of the arrangement according to the invention, shown diagrammatically;

FIGS. 3 to 10 are cross-sections and horizontal projections respectively, arranged in pairs; each pair is intended to indicate on an enlarged scale the appearance of the Web of material at different points as it passes through the arrangement;

FIGS. 11 and 12 are each cross-sections stretched, corrugated web; and

FIG. 13 shows a few samples of the material according to the invention.

The fundamental difference between the present method through a of crimping flat material and all previous crimping methtothe 'fact that the crimping process, contrary to the existing assumption, does not necessarily result in a compression of the material per unit of length, but can also be achieved by stretching the structure of the material. This yields a web of material which, per unit of length is at the most equal in Weight-even less. heavy in most Cases-40 the smooth web of material. In spite of this, a substantial crimping ratio can be obtained, e.g., in the order of magnitude of 1:2; so that after the crimped web of material has been ironed smooth, it will have, per unit of length of the original web, dimensions which have become enlarged in the same ratio. Sections of equal area of the original web of material and of the crimped web which has been ironed smooth again will then be different in weight, the ironed web being lighter in proportion to the crimpingratio.

The crimping and stretching processes are advantageously, but not necessarily, carried out at the same time. Accordingly, the web of flat material to be treated must be previously made yielding, which can be done'by spraying it with liquid, submitting it to steam treatment, heat: ing it, passing it through a bath of liquid or in any other suitable manner depending on the type of material. This treatment, however, is carried out continuously on the web of material which is moved at a constant speed.

The flat material which has been made yielding, is subjected to a continuous process of crimping and stretching, for instance by means of suitable stamping devices, grooves, being produced such that the two narrow zones of material are kept rigid along each groove and the central zone inbetween is deformed. Owing to the lateral zones being kept rigid, the central zone can only be deformed if the material in it is stretched at the same time. This process is carried out successively on a plurality of parallel grooves and yields a Web of material whose surface has been enlarged at the expense of the thickness of the material at the point concerned. The differences in thickness transverse to the grooves of the web of material can result, as required, in thinner groove walls and thicker edges or, conversely, in thicker walls and thinner edges (FIGS. 11 and 12).

If, by way of example, the web of material is grooved in its longitudinal direction, it will retain after the completed crimping and stretching process approximately the same width as before. In other words, the web of material is grooved while preventing any substantial transverse shrinkage so that the material is transversely stretched. If the web thus crimped is ironed smooth again, the resultant width of the web will be enlarged by the amount of the crimping ratio.

The stretchingof the flat material depends primarily on the depth of the individual grooves and may be greater or less according to the type of material. If a Web of material has to be more deeply grooved than is com patible with its stretching capacity, grooving is carried out in several successive stages, it being possible for the web of material to have a somewhat smaller width between each two stagw. The final result will then be a crimped web of material which, although having the desired depth of groove, is less wide than the original smooth web; here, too, however, the surface is enlarged at the expense of the thickness of the material. v

The crimped web of material generally requires an aftertreatment, drying for instance, in order to re-harden it, and can then be divided up into narrow strips and wound on to magazine rolls or made up into filters immediately. o

For certain purposes, for the production of webs of filtering material for instance, perforation of the flat material may be desirable. This is suitably done before the web of material has been made yielding or after it has been re-hardened with or without aftertreatment subsequent to the crimping and stretching process. The perforation methods suitable for the present purpose are describedin my U.S. Patent 2,847,086 and can, mutatis mutandis, beused here. For such webs of filtering material it may also be adayntageous to interrupt the regular i grooving of the crimped material, which can be done by means of a second grooving with the grooves running in a different direction. This cross grooving must of course also be effected when the material is still yielding. Finally, it should also be pointed out that for filtering purposes the material can be so vigorously stretched that randomly instance, runs from the delivery roll 2 through a perforator consisting of a toothed roller Sand a corresponding counter roller 4, or of other suitable perforating members. After passing through this perforator the web of material has ragged holes as shown in FIGS. 3 and 4. The perforated web then passes into a device 5, in which it is, for instance, moistened or treated with aqueous steam so as to give it the desired yieldingness. the tensile strength of the web of material must of course be great enough to ensure the faultless passage of the said material through the entire arrangement.

The web of material which has been made yielding and perforated is then deformed in a multistage crimping and stretching apparatus 6. Here it is assumed that stamping is effected by a number of pairs of rollers, the first of which is designated 7, 8 and the last 9, 10. Each roller 7, 8 and 9, 10 has a plurality of circumferential grooves alternating with stamping edges or lands of lesser width which project into the grooves of the opposed roller. In order to obtin a reduction in width, which is presumed to be desirable, the distance between the stamping edges of each successive pair of rollers is shortened. The same effect is achieved by increasing the speed of the roller pair 9, It) in relation to that of the roller pair 7, 8. The reduction in width of the web of material will not necessarily be as large as indicated in FIGS. 1 and 2. Particularly when the material is vigorously stretched, the web width shown by dot-dash lines will result.

FIGS. 5 and 6 illustrate the appearance of the web of material 1 after it has passed through the firstpair of rollers 7, 8 and FIGS. 7 and 8 after it has passed through the last pair of rollers 9, 10. According to the configuration of the stamping rollers, the thickness of the material can be greater either at the groove edges, as shown in FIG. 11, or at the walls, as shown in FIG. 12. The thinning of the web 1 formed by lateral stretching thereof, as well as the formation of randomly distributed cracks produced by vigorous lateral stretching, inherently results in the release of fiber ends which project from the web. After leaving the crimping and stretching apparatus 6 the longitudinally corrugated and perforated web of material 1 passes through a pair of rollers 11, 12-pricking or knurled rollers, or others of suitable.configurationwhich deform the regular longitudinal crimped folds in an irregular manner so that the longitudinal corrugated web of material possesses a plurality of longitudinal grooves which run into one another, as indicated in FIGS. 9 and 10. Next, the web of material 1 passes into an aftertreatment apparatus, which here consists of a drying plate 13 with electric heating element 14. The longitudinally crimped web of material 1 can be easily damaged in its yielding state and must therefore not be pressed against the drying plate 13 by mechanical means. Instead, an air stream directed via the nozzles 15 against the web of material 1 is provided for the purpose. This air stream can, in its turn, be heated if desired or can also be used to cool the web of material 1. c Q

Normally, a reduction in the width of the longitudinally crimped web of material occurs while the latter is being dried (not illustrated in FIGS. 1 and 2). If desired, this effect can be enhanced still further by gently compressing the web of material from the side, e.g., by means of lateral Furthermore,

streams of compressed air ejected from special nozzles. The extent of the lateral contraction of the drying web also depends, of course, on the type of material, as well as on the changes in thickness caused by the stretching process, which changes are, in their turn, determined by the shape of the stamping grooves. I

If desired, the hardened web of material 1 coming from the aftertreatment apparatus can pass through a second perforator consisting of the rollers 16, 17, in which case the first perforator 3, 4 may possibly be omitted. The web of material 1, which has thus received its final form, is now subdivided by rotating cutter blocks 18, 19 into three strips 1a, 1b, which are wound on to' magazine spools 20, 21, 22.

The arrangement shown in FIGS. 1 and 2 can be substantially simplified, according to the type of the web of material to be worked and the purpose intended for the strip filtering material produced. By way of example, the perforators 3, 4 and 16, 17 can be completely dispensed with, particularly, if randomly distributed cracks and holes are produced by adequately vigorous stretching of the material. Furthermore, grooving with only one pair of stamping rollers 7, 8 already yields a perfectly usable, longitudinally corrugated web of material, the width of the original smooth web remaining virtually unchanged. In this case, to be sure, it is advisable to employ a fineknurled pair of rollers 11, 12 so as to avoid through longitudinal ducts.

FIG. 12 shows a photograph of four samples of material, A, B, C and D which were produced with an arrangement of the type described above and having only one pair of stamping rollers. With all four samples crimping was effected in the same maner; with samples A and B, however, perforation was effected before or after the crimping and stretching process respectively, but treatment with a knurled roller was dispensed with. C and D are samples of a crimped and stretched web of material subsequently treated with a coarse or fine knurled roller respectively. In all cases the longitudinal grooving is clearly visible, the material herea thinblotting paperbeing so vigorously stretched that large cracks occur, which greatly facilitates the gathering of the webs of material, which is done transverse to the longitudinal direction of the grooves, and yields highly effective filter cords. In addition the longitudinal structure consisting of an alternately larger and smaller material thickness transverse to the longitudinal direction of the groove is clearly recognizable.

What is claimed is:

1. The method of treating an elongated web of fibrous strip material to render the same particularly adapted to be gathered laterally, formed into a cylindrical rod, and enclosed in a wrapper to make a filter for tobacco smoke, the steps comprising: treating said web to soften and render the same yielding; longitudinally grooving the softened web while preventing any substantial transverse shrinkage thereof to both form therein a plurality of closely spaced longitudinal corrugations. and laterally stretch the material of the softened web to form therein laterally spaced longitudinal zones of lesser thickness where the fibers of the material are somewhat separated; and treating the corrugated stretched web to reharden the same and set said corrugations therein.

2. The method of treating an elongated web of fibrous strip material to render the same particularly adapted to be gathered laterally, formed into a cylindrical rod, and

. corrugated torn web to reharden the same and set the enclosed in a wrapper to make a filter for tobacco smoke,

the steps comprising: treating said web to soften and render the same yielding; longitudinally grooving the'softened web while preventing any substantial transverse shrinkage thereof to both form therein a plurality of closely spaced longitudinal corrugations and laterally corrugations therein.

3. The method defined in claim 2 in which the softening step comprises moistening the web and the rehardening step comprises drying said web.

4; The method defined in claim 2 including the additional step prior to the rehardening step of somewhat flattening the corrugated torn web.

5. The method defined in claim 2 in which the softening step comprises moistening the web andthe rehardening step comprises drying said web, and including the additional step prior to the rehardening step of somewhat flattening the corrugated torn web.

6. The method defined in claim 2 including the additional step, subsequent to the grooving and stretching step, of somewhat flattening the corrugated torn web.

7. Apparatus for treating an elongated web of fibrous strip material to render the same particularly adapted to be gathered laterally, formed into a cylindrical rod, and enclosed in a wrapper to make a filter for tobacco smoke, comprising: means for treating the web to soften and render the same yielding; roller means for simultaneously longitudinally grooving and laterally stretching the material of the web to provide therein a plurality of both closely spaced longitudinal corrugations and laterallyspaced longitudinal zones of lesser thickness where the fibers of the material are somewhat separated, said roller means including at least one pair of rollers each of rigid material and having a plurality of circumferential grooves separated by lands of lesser width which project into the grooves on the other roller of said pair; and means for treating the grooved and stretched web to reharden the same and set said corrugations therein.

8. Apparatus for treating an elongated web of fibrous strip material to render the same particularly adapted to be gathered laterally, formed into a cylindrical rod, and enclosed in a wrapper to make a filter for tobacco smoke, comprising: means for treating the web to soften and render the same yielding; roller means for simultaneously longitudinally grooving and laterally stretching the material of the web to provide therein a plurality of both closely spaced longitudinal corrugations and randomly distributed discontinuous longitudinal tears, said roller means including at least one pair of rollers each of rigid material and having a plurality of circumferential grooves separated by lands of lesser width which project into the grooves on the other roller of said pair; and means for treating the grooved and stretched web to reharden the same and set said corrugations therein.

9. The structure defined in claim 8 in which the softening means comprises means for moistening the web.

10. The structure defined in claim 8 in which the softening means comprises means for moistening the web and the rehardening means comprises means for drying the web.

11. The structure defined in claim 8 including means for somewhat compressing the grooved and stretched web in advance of the rehardening means.

12. The structure defined in claim 8 in which the roller means includes at least two successive pairs of rollers, the width of the grooves on the rollers on each succeeding pair being less than the width of the grooves on the rollers of the preceding pair.

13. The structure defined in claim 8 in which the softening means comprises means for moistening the web and the rehardening means includes means defining a smooth fiat heated surface and means for blowing air against one side of the web to pneumatically press the latter against said surface.

14. The structure defined in claim 13 including means for blowing air laterally against the side edges of the web to reduce the width thereof.

15. The structure defined in claim 8 including means for somewhat compressing the grooved and stretched web following the grooving and stretching means.

16. Process of manufacturing an elongated strip of cellulosic material particularly adapted for the formation of filters for tobacco smoke, comprising the steps of: grooving paper strip longitudinally While preventing any substantial transverse shrinkage thereof to provide strip characterized by a plurality of parallel connected loops each having a ridge portion, the adjacent ridges being faced in opposite directions, and the fibers of said strip being at'least partially pulled apart laterally thereof so that said strip has projecting fiber ends on the outer surface of said ridge portions; and flattening the grooved strip somewhat to decrease its thickness.

17. Process of manufacturing an elongated rod of cellulosic material adapted for the efficient filtration of tobacco smoke comprising the steps of: grooving the paper strip longitudinally while preventing any subhaving projecting fiber ends on the outer surface thereof;

compressing the grooved strip to flatten the said loops somewhat; and consolidating said strip to form a substantially cylindrical rod longitudinally permeable to gases.

References Cited by the Examiner UNITED STATES PATENTS 8/25 Lorenz. 7/39 Davidson.

FRANK E. BAILEY, Primary Examiner.

Claims (1)

1. THE METHOD OF TREATING AN ELONGATED WEB OF FIBROUS STRIP MATERIAL TO RENDER THE SAME PARTICULARLY ADAPTED TO BE GATHERED LATERALLY, FORMED INTO A CYLINDRICAL ROD, AND ENCLOSED IN A WRAPPER TO MAKE A FILTER FOR TOBACCO SMOKE, THE STEPS COMPRISING: TREATING SAID WEB OF SOFTEN AND RENDER THE SAME YIELDING; LONGITUDINALLY GROOVING THE SOFTENED WEB WHILE PREVENTING ANY SUBSTANTIAL TRANSVERSE SHRINKAGE THEREOF OF BOTH FORM THEREIN A PLURALITY OF CLOSELY SPACED LONGITUDINAL CORRUGATIONS AND LATERALLY STRETCH THE MATERIAL OF THE SOFTENED WEB TO FORM THEREIN LATERALLY SPACED LONGITUDINAL ZONEZ OF LESSER THICKNESS WHERE THE FIBERS OF THE MATERIAL ARE SOMEWHAT SEPARATED; AND TREATING THE CORRUGATED STRETCHED WEB TO REHARDEN THE SAME AND SET SAID CORRUGATIONS THEREIN.

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