US3012302A - Tobacco smoke filter manufacture - Google Patents

Description

INVENTORS.

ATTORNEYS H. B. PARMELE TAL TOBACCO SMOKE FILTER MANUFACTURE Filed Jan. 3, 1958 their 3,012,302 TOBACCO SMOKE FILTER MANUFACTURE Harris B. Parmele, Glen Ridge, and M Sabel Block,

Bloomfield, NJ., and Clifford Oliver Jensen, Greensboro, and Marcellus W. Breitmeier, Mebane, N.C., as-

signors to P. Lorillard Company, New York, N Y., a

corporation of New Jersey Filed Jan. 3, 1958, Ser. No. 706,986 4 Claims. (Cl. 28-1) This invention relates to methods and apparatus for making filters and has particular reference to methods land apparatus for making tobacco smoke filters.

In copending application Serial N0. 367,499, filed July 13, 1953, by applicant Parmele, there is described a tobacco smoke filter, one form of which comprises textile grade fibers, such as cellulose acetate filaments of about two to about five denier gauge, of random lengths which are intermingled in such a way that when gathered into a textile roving of relatively large diameter, the longer laments extend generally longitudinally and impart the necessary drawing strength to the roving, Whereas the short lengths and the free ends of the filaments extend at various angles to the longitudinal axis of the roving. Accordingly, when the roving is radially compressed and encased in a paper tube of the required small diameter for a cigarette filter, the short lengths and the free ends of the laments form with the long filaments a labyrinthine lter which causes the smoke-borne particles to be caught or deflected out of the smoke stream in an effective and eicient manner.

ln accordance with the present invention a modified method and novel apparatus are provided for rapidly and continuously manufacturing tobacco smoke filters of the aforementioned type disclosed in said copending Parmele application.

A preferred mode of conducting the tobacco smoke filter manufacturing method of this invention comprises so treating a continuously moving and tensioned hank or bundle of textile grade filaments, such as cellulose acetate filaments, that a predetermined percentage of the laments are severed one or more times and the resulting relatively short lengths and the free ends of the broken filaments are deflected at various angles to the longitudinal axis of the moving hank or bundle to form a heterogeneous mixture, the angular disposition of shorter lengths and free ends of which is augmented by a ufng action accompanying the said treatment and further enhanced by relieving the tension on the hank or bundle before radially compressing the same to a substantially smaller diameter for encasement in the paper tube to complete the manufacture of a filter for cigarettes.

Although the foregoing method of manufacturing a tobacco smoke filter of the type described may be carried out by and in various forms of apparatus, according to this invention, a preferred embodiment of such apparatus comprises means for transversely spreading into a band or ribbon the `laments of a hank or bundle thereof by known means, such as an air blast, `or by a pair of rollers, or both, through which the ribbon or band of filaments is drawn by a pair of engaging rollers, one of which is driven and which frictionally drives the other. The ribbon or band of filaments then passes between a second set of friction rolls, which are driven at a slightly greater peripheral rate so as to apply tension to the filaments to thereby substantially unkink them in case they have been initially kinked in the filament manufacturing process, and also to maintain them in a relatively taut condition in the pass between the two sets of driven friction rolls.

interposed between the two sets of driven friction rolls and engaging the ribbon or band of filaments so as t 'v nited States Patent O Ice 3,0l2,32

be driven thereby is a roller provided with a plurality of hooked barbs having knife-like tips and which penetrate the ribbon or band of filaments so that the hooks or barbs catch, pull and then sever some of the filaments when the barbs are withdrawn from the ribbon or band. The hooks of the barbs are preferably directed generally oppositely to the direction of movement of the ribbon or band and consequently also to the direction of rotation of the barbed roller, so that they readily withdraw from the ribbon or band as both it and the roller advance, except for those filaments which are caught by the barb hooks and they are not released until severed in the manner described. In order to insure that the hooked barbs penetrate through the ribbon or band of filaments, the latter is directed between fixed guides and the barbed roller is positioned to deect the ribbon or band so that it is, in effect, pressed down upon the barbs. Although the hooked barbs catch and eventually sever a predetermined percentage of the laments, those barbs which dol not perform that function and which constitute the majority of the barbs, perform a sort of carding action which causes the filaments to fluff, thus enlarging the apparent size of the ribbon or band.

Because the filaments in the ribbon or band are under tension and are further tensioned when caught and pulled by ya barb hook, they snap or recoil when severed, so that the shorter severed lengths and the free ends of severed filaments move at an angle, largely crosswise to the longitudinal axis of the ribbon or band, and this crosswise movement is enhanced where the filaments were originally kinked since they tend to return to the kinked attitude and recoil thereto. The usually heterogeneous `arrangement of the filaments in the ribbon or band, and the fiufiing thereof, is further enhanced after the ribbon or band leaves the second set of driven friction rolls, inasmuch as the tension in the filaments is then relaxed, with the result that the filaments tend to return to their initial kinky state and the accompanying contraction displaces the short lengths-and free ends of severed filaments still further out of longitudinal alignment in the ued ribbon. 'Ihe released ribbon or band becomes a large diameter bundle of heterogeneously arranged filaments and, when radially compressed into a materially smaller diameter rope and encased in a paper tube, becomes a highly efficient labyrinthine type of tobacco smoke filter. The filaments may bebonded together by treating the filaments with a suitable plasticizer or adhesive, preferably before the filament bundle is encased in the paper tube, as is described in Crawford and Stevens Patent No. 2,794,239, for example.

It will be seen that the method and apparatus for making tobacco smoke filters in accordance with the present invention provide for the rapid, continuous and eicient manufacture of highly effective filter units at low cost and with uniformity of filtering efficiency and draw for a great multiplicity of such units.

For a more complete understanding of the invention reference may be had to the accompanying drawings, in which FIGURE l is a vertical section through a machine constructed according to the invention for carrying out a preferred method of the invention and showing the ribbon or band of laments passing therethrough and being processed therein;

FIG. 2 is an enlarged face view of a portion of the barbed roller, showing the arrangement of the barb-carrying tapes on the roller, and

FIG. 3 is an enlarged view of one'of the barbs, show-n ing its hooked and sharpened tip.

Referring to FIG. 1 of the drawings, numeral 10 desig- A nates the frame of the apparatus of this invention where- Patented Dec. 12, 1961 out. Fixed at one end on a bracket 11 secured to the infeed side of the machine is an arm 12 carrying at its free end a cylindrical guide bar 13 under which passes a substantially coninuous bank or bundle 14 of textile grade filaments, preferably formed of .cellulose acetate and having a denier in the range between l andjlO. Suitable filaments of this class have been used in the manufacture of cigarette filters and are generally known as tow and one form is described in Crawford and Stevens Patent No. 2,794,239, issued .lune 4, 1957, although the invention is not limited to that type of lament but includes those equivalent filamentary and fibrous materials described in said copending Parrnele application.

The bank or bundle 14 of filaments passes over a perforate table 15 through which an air blast passes upwardly from nozzle 16 so that the laments thereof are spread apart and become arranged in a thin ribbon or band 17 of considerable breadth in a known manner, such as is disclosed in said Crawford and Stevens patent. Further or substitute spreading .of the filaments into a substantially wide but thin ribbon may be effected by the first set of rolls 18a and 13b after the ribbon or band 17 passes under a guide roller 19 mounted on a bracket 2) secured to the frame 10. Rolls 18a and 18h are not directly driven but are driven indirectly by the ribbon or band 17 as the latter is drawn by 4the second set of rolls 21a and 21h, the upper roll, 21a, being driven by a belt 22, in turn driven'by a motor 23 mounted on frame 1Q.

Rolls 18a, 18h, 21a and 21bare corrugated longitudi-v nally or axially as shown, with the resulting teeth-like ribs meshing loosely, so that they do not injure the filament but grip it sufficiently to advance it in the case of driven rolls 21a and 21h and to cause the filaments to drive rolls 18a and 18h as the ribbon or band 17 thereof is drawn through the meshing rolls. Roll 21h is loosely journalled on frame 1% and is urged bodily upwardly against a stop by spring 24 mounted so as to retract in case of an excess of thickness of lthe bank of filaments. Roll 21!) may be rubber surfaced instead of corrugated.

Although rolls 18a and '13b are driven by the ribbon or band 17 drawn between themA by rolls 21a and 2lb, the upper roll 18a is suitably braked, as by an oil pump 25 driven thereby against a resistance to ow of the oil stream, for example, by means of a throttle valve connected to the discharge port of the pump in a known manner forming no part of the present invention. Friction or other braking means may be employed with equal facility. The drag created by the braked roll V18a on the ribbon or band 17 of Yfilaments causes them to be unkinked and consequently to duif to a degree and alsoY drawn tautly by rolls 27a and 27`b journalled on ,theV Vframe and comprising looped meshing corrugated rolls similar to rolls 18a and 18b, with the upper roll 27a being driven by belt 28 from a variable speed drive 29, whose speed is so adjusted to cause upper roll 27a to rotate fat a slightly greater peripheral speed than roll 21a, so that the filaments are further straightened but not tautened to the degree resulting in breakage of the tilaments for that reason. Lower roll 2711 may be rubbersurfaced insead of corrugated, and if desired, both rolls 27a and 27b may be rubber-surfaced.

' interposed between the two sets of driven rolls 21a, 2lb and 27a, 27b, and following the guide 26, is a barbed roller 30 journalled on the frame 10 in such position that its periphery extends above the straight pass of the ribbon or band 17 of filaments between guide 26 and a fixed guide 31 mounted on the frame. l

The barbs 32 extending generally radially from the roller 30 are of special construction, comprising not only barbs having the rearwardly deected hooks 32' of a textile card but barbs whose tips 33 are ground or other- Wise sharpened so as to be provided with a relatively sharp, knife-like edge, as is shown in the enlarged elevation of FIG. 3. These sharpened hooked barbs 32 are arranged in closely spaced relation on the roller 3G in the manner illustrated in FIGS. l and 3, with the curved portions or hooks 32 with the sharpened tips 33 thereof deected rearwardly or opposite to the direction of rotation of roller 30, as previously stated. As is also shown in FIG. 2, the hooked barbs 32 are mounted on tapes 34 which are wound spirally around the roller 39, so that the hooks 32 of the barbs 32 are arranged at a small angle to the plane of rotation of roller 30 and consequently extend partially across the line of rectilinear movement of the filaments of ribbon or band 17, which is indicated by the arrows in FIG. 2.

Barbed roller 3G is not positively driven but is rotated by the ribbon or band 17 drawn over it in the manner described, and its rotation is braked by oil pump 35 operating like oil pump brake 25 previously described, but any suitable friction brake retarding the rotation of roller 3b* may be employed with equal faciiity. The purpose of so braking the barbed roller 3d is to insure that the barbs 32 penetrate through the band or ribbon 17 On penetration by the barbs 32 into and through the ribbon or band 17, the barbs do not catch or hook onto the filaments, but on withdrawal therefrom some of the hooks 32', not only because of their hooked configuration but also because they are inclined at an angle to the filaments. in the ribbon or band 17, catch and hold certain individual filaments and when the barbs are withdrawn from the ribbon or band their relatively sharphooked tips 33 sever the caught filaments. rl`he percentage of severed laments ranges between 5 and 30% of the filaments, depending on requirements, some of the filaments being severed more than one time so as to leave short fibers of random lengths.

The percentage yof laments that `are severed by the barbs 32 may be adjusted either by changing the spiral pitch at which the barb-carrying tape 34 is wound on the roller 30, or by tilting the rotational axis of the roller 39 relatively to the rectilinear direction of movement of the filaments, indicated by the arrows in FIG. 2. This tilting may be effected by pivoting one journal 36 of the roller 3l) on its pillow block 37 and making the opposite ljournal 38 slidable on its pillow block 39 with the lock bolts 4() thereof passingV through an arcuate slot 41 in the pillow block 39, as shown in FIG. 2. Thus, when journal 3S is adjusted so that the axis of the barbed roller 35 is moved to a position such as is indicated by the dotted line 42, the angular relation between the hooks 32 of the barbs 32 and the rectilinear path of the filaments in ribbon orband 17 is increased, thereby increasing the number of filaments that will be caught and severed by the barbs 32. It will be Vunderstood that either the spiral winding of the barb tapes 34, or the angular adjustment of the barbedy roller 3), or both, may be employed to increase or decrease the percentage of filaments in ribbon or band 17 that are severed.

As the barbed roller 36 is rotated by the moving ribbon or band 17 against the drag of oil pump 3S or other braking means, the counterclockwise rotation thereof and the rearward deection of the hooks 32', causes the barbs 32 to be Withdrawn from the ribbon or band in the manner shown in FIG. l, save only those filaments which are caught .by the barb hooks 32', and which are pulled downwardly out of the relatively straight pass of the tensioned ribbon or band 17 and severed in the manner described. VThe uns'evered filaments are accordingiy carded after theV fashion of the conventional carding operation. Those filaments that are severed are relieved of Vtension and accordingly recoil, not only because of the tension imposed on them by rolls 21a, 2lb and 27a, 2717, but because of their tendency to return to their original kinked or crimped condition. Consequently, the

severed ends of the filaments as well as the short lengths where the filaments are severed more than once, assume heterogeneous crosswise positions with Vrespect to the unsevered filaments, thereby forming a rudimentary labyrinthine structure within the ribbon or band 17.

The operation of severing and cai-ding the filaments in ribbon or band 17 is a continuous one as the latter moves under tension between rolls 21a, '2lb and 27a, 27h. Following rolls 27a and 27h, the tension on the filaments in ribbon or band 17 may be entirely relaxed, preferably only partly so, but in either case the tendency of the filaments to restore themselves to their original kinked or crimped state is augmented, thereby resulting in an increase in the mutual heterogeneous arrangement of the filaments, both severed filaments, with accompanying fluffing of the ribbon or band to something resembling a large diameter roving 17 and having the drawing strength of a textile roving.

If desired, the filaments in band or ribbon 17 pass through a spray booth 43 While they are still spread out as a ribbon or band and to that end additional rollers 44a and 44b may be provided beyond the spray booth 43. ln the spray booth 43, upward and downward sprays of a suitable plasticizer of the filaments are directed upon the filaments, such asdibutyl phthalate, triacetate triacetin, triethyl citrate or other suitable odorless and tasteless plasticizer, or an adhesive like a solution of cellulose acetate, in the manner described in said Crawford and Stevens patent. In this way the filaments become tacky and adhere at their points of Contact. The spray booth 43 may be installed between the barbed roller 30 and the outfeed rolls 27a, 27b, in which case the supplementary rolls 44a and 4417 will not be necessary to hold the filaments spread out to permit greater coverage of the plasticizer or adhesive.

The band or ribbon 17 of filaments expanded into an enlarged bundle or roving 17 in the manner described, whether or not the filaments have been rendered tacky, is then fed to a suitable machine for forming it into filter plugs. This may be a plug-making machine of the type disclosed in Parmele U.S. Patent No. 2,793,572, dated May 28, 1957, and is indicated generally by the numeral 45. Preferably by feed rolls located within machine 45, which are adjustable, the tension on thev bundle or roving 17 may be varied at will, in the manner described in connection with rolls 2in, 2lb and 27a, 27b. In that way the draw and filtering action `of the ultimate cigarette filter may be adjusted and closely controlled, i.e., by applying tension on the crimped filaments they are straightened so as to decrease the suction necessary to draw smoke therethrough and vice versa. In the same way the increase or decrease of tension on the filaments will vary the filtering effectiveness of the filter, since the heterogeneous relation constituting the labyrinthine effect will thus be modified.

The enlarged roving or bundle 17 is first compressed into a small diameter rope, then encased in a paper Wrapper of the filter plug diameter and severed into filter plugs in the manner described in said copending Parmele application.

The barbed roller may be mounted above the ribbon or band 17 instead of beneath it as shown, a card roll similar to roller 30 may follow the hooked barb roller 30, but the barbs of such following roller would not be hooked and would lie parallel to the filaments and perform a carding function to augment the aforementioned flufiing and modify to a degree the heterogeneous arrangement of' the filaments, or a second hooked barb roller like 30 would follow 30 to perform the same function as 30, this second hooked barb roller being arranged in tandem or above but ahead of the roller 30 shown in FIG. 1.

The operation of the filter making apparatus of this invention has been described and also the conduct of the novel process of this invention, but it wiil be understood that the invention is not limited thereto or thereby, except within the scope of the appended claims.

We claim:

1. A method of making tobacco smoke filters, which comprises subjecting a band of elongated textile filaments to longitudinal tension, severing a predetermined percentage of said filaments in said band while under such tension, whereby the Severed portions of said filaments assume heterogeneous angles with relation to the longitudinal axis of said band, relaxing the tension on said band to enhance said heterogeneous angular relation and allow the band to expand into a bundle of enlarged crosssecti-onal dimensions, and compressing Iand encasing said bundle in a Itubular wrapper while said filaments are in said heterogeneous angular relation.

2. A method of making tobacco smoke filters, which comprises subjecting a band of kinked elongated textile filaments to longitudinal tension to thereby at least partially unkink the filaments, severing a predetermined percentage of said filaments in said band while under such tension to enable said severed filaments to assume heterogeneous angular relations to the unsevered filaments, relaxing such tension to cause the unsevered filaments to retract to at least partial kinked condition and thereby assume heterogeneous angles with relation to the longitudinal axis of said band and allow the band to expand into a bundle, and encasing said bundle in a tubular wrapper while said filaments are in said heterogeneous angular relation.

3. A method of making tobacco smoke filters, which comprises subjecting a band of kinked elongated textile filaments to longitudinal tension to thereby at least partially unkink the filaments, severing a predetermined percentage of said filaments in said band while under such tension, whereby the severed portions of said filaments retract to at least partial kinked condition and thereby assume heterogeneous angles with relation to the longitudinal axis of said band, relaxing the tension on said band to cause the unsevered filaments to retract to at least partial kinked condition and thereby enhance said heterogeneous angular relation and allow the band to expand into a bundle of enlarged cross-sectional dimensions, and encasing said bundle in a tubular wrapper while said filaments are in said heterogeneous angular relation.

4. In apparatus for making tobacco smoke lters, the combination of spaced means for holding a band of elongated filaments in substantially parallel relation, a plurality of acutely inclined barbs having knife-like tips and interposed between said spaced means, means for relatively moving said band and barbs into and out of mutual engagement for severing a predetermined proportion of said filaments within said band, means for forming said band into a bundle and means for encasing said bundle in a tubular wrapper.

References Cited in the file of this patent UNITED STATES PATENTS 1,764,524 Reber June 17, 1930 1,933,222 1 Rooney Oct. 31, 1933 2,077,320 Hale et al. Apr. 13, 1937' 2,419,320 Lohrke Apr. 22, 1947' 2,469,245 Russell lviay 3, 1949 2,641,027 Taylor .lune 9, 1953 2,707,308 Taylor et al. May 3, 1955 2,748,427 Stewart et al. .Tune 5, 1956 2,794,480 Crawford et al. June 4, 1957 `739,549 Germany Sept. 29, 1943

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