US 3650168 A
A rotary slitter, for slitting a strip of thin material into narrower ribbons and establishing the speed of travel of those ribbons, is provided with output-disengaging means of dynamic nature, moved by and with the elements of the slitter, enabling the minimization of tension on the exiting ribbons. A pair of ribbon-engaging rollers, driven at a peripheral speed slightly greater than the speed of travel of the ribbons, receives the ribbons from the slitter in side-by-side relationship and under slight tension. From the rollers the ribbons may optionally pass to an anvil member with which a cutter cooperates to cut the ribbons into discrete small pieces.
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Description (OCR text may contain errors)
1451 Mar.21, 1972 United States Patent Ruschmann  OPERATING IIPON STRIPS OF THIN PATENTEI] MAR 21 i972 SHEET 1 UF 2 /N VEN 70A HENRY E RUSCHMA/VN A T TOPNE Y OPERATING UPON STRIPS OlF THIN MATERIAL This invention relates to operating upon strips of thin material, typically of foil, and more particularly to continuously operating apparatus for subdividing such strips into narrower ribbons or into discrete small pieces. By the term foil I refer to material either of metal or of plastic, plated or unplated, single-ply or laminated, of a thickness which may vary from a small fraction of a mil up to many mils.
For the widthwise subdivision of such strips there is well known a rotary slitter typically made up of two interrelated elements each comprising an assembly, on a respective shaft, of concentric discs spaced from each other by circular spacing means of smaller radius, the two shafts being appropriately journaled so that the discs of one element extend slightly between the discs of the other, the shafts being subjected to rotation, in opposite directions at similar peripheral speeds, which draws the foil strip into the crevice at which the slight overlap of the discs begins and there effects the slitting of the strip. From there each ribbon must pass on through the region of overlap; as they pass the plane containing the axes of the slitter elements, alternate ones of the ribbons are disposed between discs of one element and the intervening ones are disposed between discs of the other element. The ribbons pass on to exit from the slitter beyond the region of overlap; in so passing, however, each ribbon as a result of friction between its edges and the respective discs between which it was formed is prone to remain between those discs-a tendency which unless overcome frustrates the exiting of the ribbons from the slitter. To rely solely on the exertion of tension on each output ribbon is usually quite impractical in view of the magnitude of the tension required, and recourse has therefore been had to one or another form of stationary disengaging means extending into the spaces formed between the discs of each element. Such means, however, when taken in their entirety (i.e., with mountings etc., which their incorporation necessitates) normally occupy principally space not occupied by the rotary elements of the slitter proper, they interfere with accessibility for start-up and similar purposes, and their dependability leaves something to be desired; furthermore they entail sliding friction of the ribbon surfaces against them.
It is desirable that the ribbon-disengaging action be accomplished by dynamic means-eg., which are not stationary but instead move with the elements of the slitter-which moreover are principally contained within space which is in any event occupied by the slitters rotary elements, which pose no interference with accessibility, and whose action is of enhanced dependability; furthermore they entail essentially no sliding friction of the ribbon surfaces against them. With these dynamic means the tension required on the output ribbons becomes a slight tension only. This feature, which is advantageous in any case, is especially so in the case of relatively extensible materials (such as Mylar) and small thicknesses of the strip (such for example as 0.0002 inch), in order to avoid significant stretching (which is always undesirable, and is ruinous to appearance in the case of plated foils).
For some purposes it is acceptable that the output ribbons be delivered from a slitter to subsequent functions-eg., cutting, reeling on a common reel, or other function-in sideby-side relationship; for other purposes the ribbons are to be delivered to individual destinations-eg., reeled on individual spools-each of which may for its own purposes provide some tension on its respective ribbon. In either case I have found advantageous the collection of both the alternate and intervening ribbons from the slitter in side-by-side relationship and under light tension; this may be done by a ribbon-contacting roller assembly downstream from the slitter, and means for imparting to that assembly rotation at a peripheral speed at least slightly greater than the speed or ribbon travel.
A particular such subsequent function may be the cutting of each ribbon into discrete small pieces, such as slivers. In my prior U.S. Pat. No. 3,156,283 I disclosed a method and apparatus for the production of slivers in which a rotary slitter was used at a final stage. There are, however, requirementsin respect of nature of the foil material to be cut, dimensions of the final product, or the like-for which I have found preferable an initial slitting of the strip into ribbons followed by the cutting of the slivers from those ribbons. For this purpose the exit ribbons may pass directly from such a ribbontensioning means as is referred to in the last preceding paragraph to an anvil member with which a cutter (for example, a rotary cutter of the general nature of one of the cutters disclosed, for a quite different purpose, in U.S. Pat. No. 3,491,636 to Braun) cooperates to sever the slivers form the ribbons.
Important objects of the invention have been made apparent by the foregoing introduction. Allied and other objects will more fully appear from the following description andthe appended claims.
An important aspect of the invention, then, concerns a rotary slitter having two rotary slitter elements whose axes are parallel and each of which comprises a respective series of spaced discs centered on its axis and intertting in slightly overlapping relationship between the discs of the other element, for slitting the strip into and establishing the speed of travel of a plurality of narrow foil ribbons of which, as they pass the plane containing said axes, alternate ones are disposed between discs of one element and the intervening ones are disposed between discs of the other element. The slitter is provided with dynamic ribbon-disengaging means, comprising members moved by and with the elements, initially effective on each of the foil ribbons substantially at the axescontaning plane. With the foregoing there are employed means, including a ribbon-contacting roller assembly downstream from the slitter and means for imparting thereto rotation at a peripheral speed at least slightly greater than the speed of ribbon travel, for collecting both said alternate and said intervening foil ribbons from the slitter in side-by-side relationship and under light tension.
In another aspect of the invention there are combined, with the subject matter of the immediately preceding paragraph, an anvil member downstream from and onto which the ribbons pass in side-by-side relationship from the roller assembly, and a cutter cooperating with the anvil member to cut the ribbons into discrete small pieces. The ribbons may pass without longitudinal tension thereof from the pair of rollers to the line of interaction between cutter and anvil member, and means may be provided between the pair of rollers and that line for maintaining direct the path of the ribbons therebetween; that line may be relatively close to the pair of rollers thereby to minimize the distance of such passage.
In the detailed description of the invention hereinafter set forth reference is had to the accompanying drawings, in which F IG. 1 is a vertical cross-sectional view taken longitudinally through a typical apparatus according to the invention;
FIG. 2 is a vertical view of the rotary slitter alone, taken looking upstream (the line 1-1 in FIG. 2 indicating the plane along which FIG. 1 is taken);
FIG. 3 is a plan view of portions of the apparatus downstream of the` slitter and showing the ribbons formed by the slitter; and
FIG. 4 is a vertical cross-sectional view taken along the line 4-4 of FIG. 3.
FIG. l shows the apparatus with a strip l entering it from the left. In view of the thin nature of that strip it will be understood that its thickness-and that of the ribbons 4 and 3 into which it is subdivided by the slitter-as appearing in FIG. l has, in the interest of clarity of illustration, been greatly exaggerated. The strip may be continuously drawn from a supply roll (not shown) diagonally upwardly onto a smooth table 15; in its passage along that table the strip may slide under a transverse bar or plate 16 whose extremities may be loosely retained by stationary pins 17 and which has a smooth bottom surface resting on the moving strip. The table 15 may extend to within a short distance of the disc-overlap region of a rotary slitter 20, through which that strip passes and which slits it into a number of narrower ribbons (best seen in FIG. 3), alternate ones of which are designated as 4 and in the intervening ones as 3.
The slitter 20, in accordance with preferred known practice, may comprise interrelated lower and upper elements each comprising an assembly of concentric discs and circular spacing means on a respective shaft. The upper element,`
whose shaft is 22, may comprise an alternation of hardened discs 24 with spacing means 26 (which preferably are also hardened) of smaller radius but similar thickness; the lower element, whose shaft is 21, may comprise an alternation of corresponding spacing means 25 and corresponding discs 23-and may if desired include at each end a disc 29 of enlarged radius to provide lateral guidance for the entering strip 1. The shafts 21 and 22, which are journaled in suitable fixed bearings (not shown), are appropriately positioned relative to each other to bring the uppermost peripheral portions of the discs 23 between the lowermost peripheral portions of the discs 24; the amount of overlap, which is preferably small, has been exaggerated in the drawings for clarity of illustration.
Each of the shafts 2l and 22 may be coupled to a drive motor through suitable positive-coupling means (schemativ cally indicated at 19) so that they execute oppositely directed rotations (21 clockwise, 22 counterclockwise, as viewed in FIG. 1) at identical peripheral speeds. lt is such rotation of those shafts which draws thestrip l onto and along the table l5, and which determines the speed of travel of the strip through the apparatus. A
The cutting action of the slitter and thus the formation of the ribbons 4 and 3 from the strip 1 of course takes place as that strip enters the region of overlap of the discs 23 and 24- i.e., slightly upstream from the vertical plane containing the axes of the slitter elements. At that vertical plane the ribbons 4 will be in contact with the bottom peripheries of respective discs 24, while the intervening ribbons 3 will be in contact with the top peripheries of respective discs 23.
In each of the two elements of the slitter the disengaging means according to the invention may comprise annular members-designated as 27 in the lower element and as 28 in the upper-intervening between that. elements successive discs, each in surrounding relationship to a respective one of that elements spacing means; they are at least slightly thinner than the spacing discs, so that they intervene freely between the respective discs. In each element those annular members have an external radius greater than that of the discs, and an excess of external over internal radius slightly less than the excess of disc radius ever spacing-means radius.
Means (seen in FIG. 1) are provided upstream from each slitter element for causing the centers of that elements annular members 27 or 28 to be slightly more downstream than the axis of that slitter element. Such a means for the upper element may be a roller 32 appropriately journaled at a level somewhat above the axis of the upper element; for the lower element it may be a roller 31 appropriately journaled at a level somewhat below the axis of the lower element. In the case of the upper element gravity causes an outer-peripheral point on each annular member 28 to rest or bear against the top of the respective ribbon 3; the up-and-downstream position of the roller 32 may be such that the inner periphery of that annular member 28 will just or almost contact the respective spacing means 26 at a point on the latter (such as B in FIG. l) somewhat upstream from the plane containing the axes of the slitter elements. In the case of the lower element gravity causes an inner-peripheral point on each annular member 27 to rest or bear against an upper-peripheral point on the respective spacing means 25; the up-and-downstream position of the roller 3l may be such as to cause that upper spacingmeans point to be a point (such as A in FIG. 1) somewhat upstream from the plane of the slitter-element axes, and to cause an outer-peripheral point on that annular member just or almost to contact the bottom of the respective ribbon 4.
Optionally in the case of the lower element there may be employed an additional roller 33, appropriately journaled below the axis of that element and somewhat downstream from the plane containing the slitter-element axes, against lwhich an outer-peripheral point on each of the annular members 27 may bear. When the roller 33 is employed it is that roller and the roller 31, taken together, which determine the exact positions of the annular members 27; by suitable adjustments of the positions of the two the above-mentioned bearing of each of those annular members against the spacing means 25 may be relieved, and at the same time the above-mentioned contacting of the respective ribbons 4 by those annular members may be more accurately controlled.
While the annular members 27 and 28 are free with respect to the other portions of their respective slitter elements, they nevertheless engage in rotation along with those elements, obviously however being also meanwhile forced continuously to shift radially with respect to those respective elements. By the annular-member rotation the rollers 3l and 32 (and 33 if em ployed) are rotated in the directions indicated by arrows in FIG. l.
As a result of the annular-membertodisc relationships set forth in the last few paragraphs the radial distance by which the outer periphery of each annular member 28 is inset from the peripheries of the adjacent discs 24, which distance was at a maximum at a point in radial alignment with B, progressively diminishes downstream from that point, being already diminished at the plane containing the slitter-element axes and reaching zero at a position (such as that of D in FIG. l) not far distant downstream from the region of disc overlap; likewise the radial distance by which the outer periphery of each annular member 27 is inset from the peripheries of the adjacent discs 23, which distance was at a maximum at a point in radial alignment with A, progressively diminishes downstream from that point, being already diminished at the axes-containing plane and reaching zero at a position (such as that of C IN FIG. 1) not far downstream from the region of disc overlap. Thus in passing even infinite similarly downstream from the axes-containing plane each ribbon 3 is being progressively displaced by the respective annular member 28 away from the axis of the upper element, so that static friction between it and the discs 24 between which it was formed-which tends to cause it to remain at a constant radial distance from the upper element axis-is at once overcome; a corresponding progressive displacement is effected on each ribbon 4 by the respective annular element 27, with a corresponding result. It may be that the freedom with which the annular members 27 and 28 are carried by their respective slitter elements contributes in some additionalway or ways to the effectiveness of the arrangement. In any event the net operational effects are high reliability of operation, essential elimination of friction against the surfaces of the ribbons, and the significant reduction of required exit tension introductorily referred to above.
For the provision of the appropriate slight exit tension-or of more were there to be employed lesseffective-ribbon-disengaging means-I provide a ribbon-tensioning means 40 acting in common on all the side-by-sde exiting ribbons. Between the slitter 20 and the ribbon-tensioning means 40 the tensioned ribbons may slide along the top surface of a table 35, whose upstream portion may be a plate 34 extending to within a short distance of the region of slitter-disc overlap. The top of portion 34 may be in horizontal alignment with the top peripheries of the discs 23, thus affording an opportunity for the ribbons 3 to leave the slitter in a quite horizontal path; to accommodate to the slightly inclined path which the ribbons 4 must take (whose inclination has suffered exaggeration in F IG. l in the interest of clarity of illustration) the marginal upstream surface of portion 34 may be slightly rounded. In their passage along the table 35 the ribbons may if desired slide under a smooth-bottomed transverse bar 36 whose extremities are loosely retained by stationary pins 37; the bar 36, if employed, is preferably of light material so as not to contribute appreciably to the ribbon-tensioning requirement.
The ribbon-tensioning means 40 may comprise a ribboncontacting roller assembly made up of a pair of ribbon-engaging rollers 4l and 42 between which the ribbons pass in sideby-side relationship, and into close proximity to which the table 35 may extend. The rollers are biased toward each other so as to grip the ribbons. They are appropriately driven at a peripheral speed slightly greater than the linear speed of travel of the ribbons established by the slitter; thus there is at least slight slippage of each ribbon relative to the rollers, accompanied by a tensioning of each ribbon in its extent between slitter and rollers. The surface of at least one and preferably of each of the rollers is resilient, thereby to enhance the independence of the action of the pair of rollers on each ribbon from its action on the other ribbons; desirably that surface is also friction-prone but wear-resistant, and Neoprene rubber has been found suitable for the purpose.
In the drawings the lower roller is 41, its surface layer (e. g., of Neoprene rubber) is 43, and its terminal shafts are 45; the upper roller is 42, its surface layer 44, and its terminal shafts 46. For the journaling of those shafts there may be provided at each side of the apparatus an appropriate fixed standard such as illustrated at one side as 50; the shafts 45 may be journaled in those standards. In its upper portion each of those standards may have formed into spaced bifurcations 51 and 52, surmounted by a crossmember 53. Between the bifurcations of each standard there may float a block 54 into which the respective shaft 46 is -journaled; a screw 58 may extend downwardly through that standards crossmember 53 carrying at its bottom an inverted cup 57, and between the upper inner surface of that cup and the bottom ofa recess 55 in the top of the block 54 therebelow there may be compressed a spring 56 whose effect is to bias the roller 42 against the roller 41. With any given roller surfaces the tension exerted by the tensioning means 40 on the ribbons exiting from'the slitter 20 may be regulated by the choice of roller speed and the adjustment of the roller bias-the latter of course by adjustment of the screws 58.
At a common end of the rollers 41-42 their shafts 45 and 46 may respectively carry intermeshing identical gears 47 and 48 commanding the rotation of the rollers (4l clockwise, 42 counterclockwise, as viewed in FIG. 1) at identical peripheral speeds. The shaft of one of the rollers (e.g., that of the lower roller 41) may be coupled to the drive motor 10 through suitable positive-coupling means (schematically indicated at 49 in Flg. l) chosen to result in the rotation of the rollers at the peripheral speeds above referred to. Vertically the rollers 41-42 may be positioned so that the bottoms of the ribbons 4 and 3 passing between them are at the level of the top of the table 35 above-mentioned.
From the pair of rollers 41-42 the ribbons 4 and 3 may of course pass on in any desired paths to any desired destinations, which may for example be individual to the respective ribbons. On the other hand there are various end-product requirements for which advantage may be taken of the presentation of the ribbons in side-by-side relationship from that pair of rollers. One such end-product requirements is for small discrete pieces to be cut from the ribbons-by way of nonlimitative but specific example, slivers of stainless-steel foil of about 0.002 inch thickness, each sliver being about 0.004 inch width and about 0.080 inch length, that length being conveniently the width of the ribbon. For such purposes it is highly convenient that the ribbons pass, still in side-by-side relationship, from the pair of rollers 41-42 onto an anvil member which is provided downstream form the rollers and with which a suitable cutter cooperates to cut the ribbons into the discrete small pieces-eg., the slivers just mentioned.
Such an anvil member is shown in the drawings as 60. Its top may lie in the plane of the tops of plate 34 and table 35. The top downstream portion 61 of the anvil member 60 may be formed as an insert removable from the rest of that member, and the downstream face of the portion 6l may be inclined so as to render acute its angle of intersection with the top surface of that portion-which intersection, lying on the locus of movement of the cutting edges of the cutter referred to in the next succeeding paragraph, forms the line of interaction between cutter and anvil member. To minimize the frequency of required resharpenings of the portion 61 at that line the portion 61 may be formed of hard and abrasion-resistant material such as tungsten carbide.
The cutter 70 may for example be, and for such an end product as the slivers mentioned above preferably is, a rotary cutter. lts shaft 71 may be appropriately journaled, for example at the level of the top of 60-61, to bring the locus of the cutters teeth into the above-described relationship to 61, and may be coupled through suitable positive-coupling means (schematically indicated at 69 in FIG. l) to result in rotation of the cutter (counterclockwise as viewed in FIG. 1) at a peripheral speed appropriate to the desired dimension of the final product taken in the direction which is longitudinal ofthe ribbons. If that product is to be a sliver of which the width of the ribbon will be the length, that it is of course the width of the sliver which will be established by the cutter-rotation speed. That final product will of course be discharged downwardly by the cutter, and may be collected below the cutter by any suitable means (not shown).
In this organization, in which the ribbons pass without longitudinal tension from the pair of rollers 4h42 to the line of interaction between cutter and anvil, it is desirable to provide means between the roller and that line for maintaining direct the path of the ribbons therebetween. Such a means may for example be a smooth-bottomed transverse bar 66, typically of metal, resting on top of the ribbons and under which they slide in their passage along the top of 60-61. The extremities of the bar 66 may be loosely retained by stationary pins 68; preferably the holes in that bar accommodating those pins will be lined with nonmetallic inserts 67 such as of Bakelite.
,It will of course be appreciated that the invention is appropriate not only to operation upon materials of a wide range of thicknesses, as introductorily pointed out, but also to the production of ribbons of a wide variety of widths, determined of course by the thickness of the discs and spacing means in the slitter 20. (In the drawings that thickness, when taken relatively to other dimensions in the drawings, may be considered as having been chosen, arbitrarily, for a ribbon width of the very general order of 0.125 inch.) Of course likewise when the ribbons 4 and 3 are cut into discrete pieces the dimensions of those pieces longitudinal of the ribbons may be widely varied by the geometry, nature and speed of the cutter.
Whilethe entering strip l has been shown as a single one, it will of course be understood that two or more strips, in sideby-side relationship and drawn from respective rolls, may equally well be accommodated; thus for example I have with highly satisfactory results employed the disclosed apparatus, with appropriately wide slitter and appropriately long rollers 41-42 and anvil member 60 and cutter 70, to operate on two strips, in such relationship, each of 4 inch width, for the production of the above-described slivers therefrom.
While I have disclosed my invention in terms of a particular embodiment thereof, I intend thereby no unnecessary limitations. Modications in many respects will be suggested by my disclosure to those skilled in the art, and such modifications will not necessarily constitute departures from the spirit of the invention or from its scope, which I undertake to define in the following claims.
1. A machine for continuous operation upon a strip of foil comprising, in combination, (l) slitter means, having two rov tary elements whose axes are parallel and each of which comprises a respective series of spaced discs centered on its axis and intertting in slightly overlapping relationship between the discs of the other element, for slitting the strip into and establishing the speed of travel of a plurality of narrow foil ribbons of which, as they pass the plane containing said axes, alternate ones are disposed between discs of one element and the intervening ones are disposed between discs of the other element; (2) dynamic ribbon-disengaging means, comprising members carried by and moved with said elements, initially effective on each of said foil ribbons substantially at said axescontaining plane; and (3) means, including a ribbon-contacting roller assembly downstream from the slitter means and means for imparting thereto rotation at a peripheral speed at least slightly greater than said speed of ribbon travel, for collecting both said alternate ancll said intervening foil ribbons from the slitter means in sidebyside relationship and under light tension.
2. The subject matter claims in claim l wherein said collecting means further includes, upstream from said roller assembly, a surface onto which there pass, in two respective planes only slightly inclined relative to each other, the ribbons from between the discs of one of said elements and the ribbons from between the discs of the other element.
3. The combination, withv the subject matter claimed in claim 1, of an anvil member downstream from and onto which