US3036486A - Slotting segments with v-shaped cutting portion for corrugated paperboard and the like - Google Patents

Description

May 29, 1962 w. M. WILCOX 3,036,486

SLOTTING SEGMENTS WITH V-SHAP CUTTING PORTION FOR CORRUGATED PAPERBOAR ND THE LIKE Filed March 7, 1958 Izwezzimfl:

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by 8, 92 0W, *H/W ate dfidfiA d Patented May 29, 1962 ffice 3,636,486 SLOTTENG SEGMENTS WETH V -SHAfEl) CUTTENG PORTKON FOR CORRUGATED PAPEOARD AND THE LlKlE Walter M. Wilcox, Westminster, Mass, assignor to Simonds Saw and Steel Company, Fitchburg, Mass., a corporation of Massachusetts Filed Mar. 7, 1958, Ser. No. 719,872 3 Claims. (ill. 83-671) This invention relates to slotting equipment for cutting slots in compressible sheets such as corrugated paperboard used in the corrugated container industry, as Where carton tops are to be folded or where partition inserts for separating bottles, cans or the like are slotted to overlap.

Due to the compressible nature of such corrugated and laminated paperboard difficulty is experienced in slotting it on rotary machines, with frequently resultant objectionable tearing, compression and irregular deformation along one or both side walls of the desired slot.

The similar slotting irregularities are experienced in greater or less degree with the various constructions of corrugated paperboard, whether single or double faced, or of relatively heavy or light weights and grades of paper, or with one or a plurality of the fluted strata, or with the fluting of one or another form as to steepness and pitch. In general, the softer the paperboard, in the sense of yielding under lateral pressure, the greater the difficulty in effecting acceptably regular slotting.

Accordingly the present invention aims to provide im proved slot-cutting instrumentalities herein termed slotting segments, for rotary slotting machines for paperboard and the like, and which are adapted for better coaction with the opposed rotary cutter elements in such machines so as to afford more regular and generally improved slot formation.

In the drawings illustrating by way of example one em" bodiment of the invention:

FIG. 1 shows in side elevation a slotter assembly of a standard or preferred machine for feeding and acting on corrugated paperboard blanks, with the supporting arbors in cross-section, including an upper arbor mounting a holder equipped with the slotting segments of the invention and a lower arbor carrying the cooperating pair of spaced cutter discs;

FIG. 2 is a corresponding view at right angles to FIG. 1;

FIG. 3 shows an assembly of slotting segments of the invention upon a larger scale;

FIG. 4 is a cross-sectional view through one such segment, upon a still larger scale;

FIG. 5 is a fragmentary enlargement corresponding to a central portion of FIG. 2 illustrating the slotting action; and

FIG. 6 is a diagrammatic view of a portion of a corrugated paperboard blank for a box or carton typical of the products with which the invention is concerned.

With further reference to the drawings, FIGS. 1 and 2 illustrate the segmental slotting means of the invention in use at a slotting station of the usual or preferred machine for acting upon corrugated paperboard and the like compressible r heets to be slotted, as in the manufacture of boxes and cartons. Such station is generally defined by spaced parallel arbors 7 and 3, herein called upper and lower merely for identification. It will be understood that the sheets or blanks S of the paperboard are advanced along a generally horizontal path between the arbors as by rotary feed means not shown and whereby the blanks are presented in appropriately spaced and timed relation for slotting at the desired areas.

One of the arbors, herein the upper arbor 7, carries a disc-like holder or spider 9 in which the segmental circular cutter device of the invention is mounted as by means of bolts 11 adjustably receivable in ar-cuate slots 12 of the holder. The other or lower arbor 8 has fixed on it a pair of square-edged or slightly concaved rotary cutters 15, 15 spaced and aligned to receive between them the segmental cutter means to be described.

One unit of the segmental slotting means of the invention is designated as a whole at 20. It has an angular extent corresponding to the length of the particular slot to be formed, as for example a segment in the illustrated example. Such unit 20 may comprise a single arouate piece, whether for relatively short slots or in any case. For adaptability to different lengths of slots, it conveniently is made up of a plurality of segmental portions such as herein shown at 21, 22, 23. These are made available in different angular lengths adapted to be combined to provide slotting units of a total length as appropriate to the given work. For example in the instance shown there is an intermediate segment 22 of about 50 and two end segments of about 20 each, together furnishing the approximate 90 of segmental cutter unit desired in this case. Obviously the unit for the particular slotting requirement may be assembled from other lengths of segments, such as three 30 segments for a 90 unit, two 50 and one 20 segment for a unit, or four 30 segments for such latter unit, to mention but a few examples. Thus the segments may be supplied in appropriate angular lengths for production of whatever length of slotting is likely to be required.

In the illustrated example the segment unit 20 is assumed to be for slots let into an edge portion of the paperboard blanks, such for example as diagrammed at S in FIG. 6, the slots s accordingly having one end upon. The trailing slotter segment such as the member 23 herein has at the terminal edge a projection 24 with transverse cutting edge for contacting with the adjacent end of the scrap cut from the slot and for forming the closed end of the slot. It will be understood that in the case of slots other than at the edge of a blank and hence closed at both ends a similar projection is provided at the leading edge of the leading segment such as 21 hereof. Each segment member 21, 22, 23 has one or more mounting formations for cooperation with the holder 10 and bolt and slot means 11, 12, such as the bolt-receiving apertures 20 of preferred closed or open elongate form.

Heretofore the slotting of corrugated paperboard has been in the nature of a punching action performed by a substantially blunt-cornered segmental rotary plate element operating in opposition to square-edged cutters generally like those at 15, 15 herein. Such prior segmental elements have substantially solid circumferentim portions with the peripheral face substantially flat or slightly concaved and providing blunt punch-like opposed corner zones for punchshearing coaction with the opposed rotary disc pair.

In contrast to such prior practice the present invention provides slotting segments adapted to have in coaction with the opposed pair of sheet-supporting rotary members a rotary knife-cutting or slicing action whereby the resulting slots have clean straight side edges, substantially free of tearing or other irregularities and with minimum deformation of the adjacent blank material.

Accordingly, as best seen in FIGS. 4 and 5, the segmental elements such as 21, 22, 23 of the illustrated unit 20 are novelly fashioned along the outer circumference to present in effect a pair of sharp knife- edge lineal cutters 25, 25 having the cutting edges substantially in the plane of the side faces of the segment. Each such cutter 25 is defined between the adjacent side face of the segment and an inner face 26, 26 disposed at an acute angle, preferably not more than about 20 to 25 to the plane of the segment side wall and to the medial plane of the segment. Such inner walls 26 of the respective cutters 25, 25 are oppositely and inwardly inclined, defining between them a steep-walled groove of general V-form and preferably somewhat rounded at the bottom 27 where these opposed inner walls intersect in the region of the medial plane of the segment. As shown the inner walls 26 are continuous uninterrupted planar surfaces but may be stepped or otherwise formed so long as they are symmetrically oppositely disposed to provide between them a channel of a depth at least approximating that of the sheet or paperboard to be slotted, and forming at their outer junctures with the side walls of the segments: of the thin-knife-edged cutters proper such as 25. {In the illustrated example such channel has the form of a narrow deep V-groove with the walls 26, 26 thereof presenting between them an angle of approximately 45 One or more of the mounting formations such as the apertures 29, FIGS. 3 and 4, are provided in appropriate location on each plate or segment such as 21, 22, 23 of each segmental slotting unit 20, 'for cooperation with the nut and bolt or other fastener means 11 of the rotary holder 9. Such mounting formations 29 may be more or less elongate radially of the segments and may extend in from the inner margins of the segments -for adjustment and adaptability to various supporting holders.

In operation at the cutting station the knife- edge cutters 25, 25 slice through the plural layers of the sheet or blank S along spaced lines cleanly defining the sides or" a slot s. As represented in FIG. 5 the material at the respective outer sides of the cutter receives little or no compressive deformation. The scrap sc cut from the slot is in efiect straddled by and largely received between the cutters 25, 25 or may in some part enter the underlying space between the lower rotary members 15, 15. It is usually freed from the slot under the cross-cutting action of the terminal projection 24. Stripper means such as fingers (not shown) in the scrap path may if desired be provided to deflect the scrap and assist in clearing it from the cutters and the sheet.

My invention is not limited to the particular embodiments thereof illustrated and described herein, and I set forth its scope in my following claims.

I claim:

'1. For slotting corrugated paperboard and the like plural laminar composite paper webs, a slotting segment comprising a metal plate with arcuate outer margin described about a central axis of rotary support, the plate having a formation for mounting it on a rotary holder concentric with such axis, said outer margin of the plate fashioned to present in substantially the planes of the plate side faces a pair of knife-edge arcuate cutters transversely spaced by the width of the slot to be formed, each said knife-edge cutter comprising an outer side face coplanar with one side face of the segment plate and an inclined inner face at a small acute angle of not more than about 25 to the outer side face and to the medial radial plane of the segment plate, said angular inner faces of the cutter pair being oppositely and symmetrically disposed with respect to and converging inwardly substantially to meet in said medial plane and presenting between them an angle of approximately relative to each other thereby defining between them a steep-walled V-groove of an open depth at least approximating that of the laminar paper web to be slotted and adapting the peripheral knifeedges of the cutters to cleanly slice with minimal compressive action through corrugated paperboard laminae along slot-defining spaced cutting lines to provide a cut scrap having smooth sidewalls whereby said scrap will be releasably carried by said angular inner faces of the cutter.

2. A slotting segment according to claim 1 wherein an end of the segment has a generally radial outward projection with a transverse cutting edge for forming the corresponding end of a slot.

3. A slotting segment according to claim 1 wherein the bottom of the V-groove is rounded in the region of the medial plane of the segment.

References Cited in the file of this patent UNITED STATES PATENTS Re. 19,059 Schillo Jan. 23, 1934 609,896 Morris Aug. 30, 1898 1,123,532 Heynan Jan. 5, 1915 1,404,788 Moore Jan. 31, 1922 2,015,877 Thompson Oct. 1, 1935 2,117,220 Sieg May 10, 1938 2,808,106 Belton Oct. 1, 1957

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