CA1088486A - Sheet metal web handling method, apparatus and coil construct - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

The disclosure includes method and apparatus for handling elongated webs of sheet metal, and a sheet metal construct formed as an intermediate product and comprising a parent coil pre-divided into a plurality of ? coils. In one method sequence, separation can be completed by the end user of the coil just before it is fed into a press or the like. In another method sequence,separation is completed during wrapping of the parent coil. In still other sequences, completion of separation can be accomplished at stages intermediate these two.
Slitting may be done directly off a mill. Edge trim strip may be wound as part of the parent coil to simplify scrap handling, and may be used to protect the coil in transit.

Description

i88~36 BACKGRO~N~ OF THE INVENTION

In the manufacture of flat rolled metal it is most convenient and economical to form the web of a much greater width than is normally required by the end user and then slit the web into narrower strips of a suitable width. The metal web is coiled as it is processed, then, in a separate operation, placed on an uncoiler, unwound, trained through a slitter and then rewound as a number of separate narrower strips on the coiler. The slitting operation may be accomplished at the point o manufacture, by middlemen, such as warehousemen, or by the end user of the sheet metal.

Regardless Oe at what point the coil slitting takes place, inherent characteristics of the sheet metal and conventional coil slitting processes result in a number of difficulties to which the industry has responded in a manner which, in many cases, only solves the problems encountered by producing other, different problems.

~ or example, although the sheet of metal being sl-lt is generally thought oE as having a rect?ngular cross-sectlonal conEiguratlon, ln fact, conventlonal sheet metal manufactur:lng processes produce a sheet whlch ls crowned, l.e. ls thicker, at lts center than at its edges Obviously, as such a sheet ls rewound on a coiler as a series of separate strips followlng slitting, those strips slit from the center of the sheet are thicker and as a result are rewound more tightly than those strlps sllt from adjacent the edges of the sheet. This in turn results in so called ~'slack strands" being formed by the thinner strips between the slitter and coiler. To overcome the problem of slack strands a number of solutions have been advanced, and in fact are found in use today throughout most coil slltting operations.

1~84~6 One approach has been to insert pieces of cardboard or paper between the wraps of those coils positioned outwardly of the center coil to compensate for the differences in thickness of the strips being rewound.
This is often performed manually, which is both cumbersome and dangerous, and even where performed mechanically is still cumbersome and requires a specially designed machine. In both cases, the cardboard or paper pieces must be removed later as the strip is decoiled for punching, pressing or other operations.

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Two other, related approaches to the problem of slack strands are the looping and estooning of the strands intermediate the slitter and the coiler. Looping requires the provision of a deep pit, which is botll inconvenient and expenslve, whl]e festooning requlres the installation oE n serLe~ oE rol1s mounted in towers above the process llne, nn obviousLy costly expedient, and in both looping and festooning control of the slack stands is always a problem.

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While individual coilers could be provided for each of the strips resulting from the coil slitting operation, as a practical matter the expense of such provision will usually be prohibltive. ~nother approach which is based upon individ~lal treatment of the slit strips but whlch does not require separate coilers :Ls slip core winding. In this process, the strips are wound on nonmetallic cores that are allowed through friction to wind at a speed commensurate with the thickness o the strips. However, the cores used in this operation are in themselves expensive and must be retained within and shipped with the coils, and in addition ~hey may distort under load and cause irregular winding.

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Li 36 Another problem characteristic of conventional coil slitting operations which is independent of the crowned configuration of the metal sheet and would, therefore, exist even if the sheet were perfectly rectangular in cross section, is interleaving o~E the strip edges as they are rewound on the coiler. Interleaving in turn results in damage to the edges of coil, loss of production time resulting from the necessity of manually separating interleaved coils and diEficulties in feeding such coils, because of their damaged edges, through machinery such as punchlng presses and the like.

To prevent lnterleavlng dur:lng rewlnding, an attempt ls generally made to kcep the LndLv:Lclual strips separate from eacll othcr. This may be accomp:Llshed by pos:Ltionlng spacer plates between coils or through tho use of a serles of discs which are mounted on a shaft separate from the coiler and allowed to penetrate between the coil edges as they are rewound.

Regardless of the particular manner in which separation is attained, it will be seen that separation requires lateral displacement oE
the individual strips from each other. This in turn requires that the colLer be spaced a considerable distance ~rom the separator to allow the strips to fan out gradually from the slitter to the requIred spacing at the coiler. Ordinarily, to obtain a total lateral displacement of approxlmately two to three inches it is necessary to provide from fifteen to twenty feet of spacing between the slitter and the coiler.

From the above it will be apparent that conventional coil slitting operations possess many inherent disadvantages and present many problems which have traditionally either been accepted or only partially solved, often at the e~pense of introducing other difficulties and new problems into the process. A need therefore, has long e~isted for a new . ~
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approach to coil slitting which obviates the problems of slack strands and coil interleaving and all of their attendant disadvantages.

SUM~RY OF THE INVENTION

In accordance with the present invention coil slitting is accomplished in a two step operation which permits all of the strips slit from a single sheet to be rewound as a unit and thereby obviates the traditional coil slitting problems of slack strands and coil interleaving.

Although cutting web material in more thall one cuttLng step is not unknown (see for example, U.S. Patent No. 876,00~), :Lncluding cutting o~ metal str1ps ln more than onc step (U.S. I'atent Nos. 3,628,710 and 3,641,853), in such prior art cuttlng processes completion of cutting is accomplished before rewinding of the sheet being cut has commenced.
~s a result, the same problems of slack strands and interleaving that occur in conventional, one step cutting processes would occur in a two step process where the final cutting step is accomplished before rewinding has commenced, to the same extent that they would have occurred had the cuttlng been acco~lplished in only one step.

In contrast, in accordance with the present invention, as the unslit sheet is unwound from the uncoiler and trained through the slitter, the sheet ls only partially slit or cut, or is fully slit and immediately lightly reconnected to provide the equivalent of partial slits or cuts, resulting in a set of interconnected strips which are delivered to the coiler as a single sheet.
Thereafter, after rewinding has commenced, that is, at any t-lme between the time when the interconnected strips have begun to wrap the coiler reel and such time as the coils are unwound for use, the partial cuts or equivalents made at the slitter may be completed to provide the separate, narro~Jer coils desired.

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Since, until the partial cuts or equivalents made at the slitter are completed, the interconnected strips behave as a single she~t, they can be treated as such durlng coiling without fear of slack strands, strip interleaving and all of their attendant problems and difficulties.

In accordance with one embodiment of the invention, complete separation of the coils is not made until the coils are ultimately unwound by the end user as, for example, they are fed into a press. In accordance with this embodiment, an additional advantage is gained over and above those discussed above in that individual banding and handling of separate coils following the slitting operation are eliminated. Or the coils may be individually broken off as units, preferably by the end user, rather than being individually unwound ln whlch case lndlvlduaL handlLn~ l~ay both (1) be more eEElcient than Ln conventional practlce and (2) requ:lre llttle chall~e Erom conventlona:L practlce ln utlli~Lng ordlnary handllng eqllLpmel~t such as cranes or lift trucks to transport and position indivldual sllt colls.

In accordance wlth another embodiment of the invention, completion of the partial cut ls made during the first wrap of the coils on the coiler mandrel, In accordance with this embodiment of the invention, final separation ls made preferably as close as posslble to the beginnlng of the second wrap, alLow:Lng the E:Lrst wrap oE lnterconnected æheets to tllereby act as a wrapper Eor the separ,ated coils.

Regardless of whether final separation is accomplished on the coiler or at some later stage, the final parting arrangement can be relatively simple.

In a conventional slitter opposed pairs oE rotary cutters are used at each cut, which results in adjacent edges of ~he slit colls being momentarlly displaced from each other in a direction perpendicular to the plane of the sheet. In the practice of the present invention, the same ,.

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., : ., ... . ' :`~ ' ` ' ' 884~6 momentary displacement may occur at longitudinal locations where slitting is complete, but the resulting series of interconnected strips may also experience a degree of relative displacement of adjacent edges at longitudinal locations where slitting is not complete, which displacement may be maintained until the adjacent strips are separated, unless the strips are knocked back down into a common plane while maintaining the connection between slits, as is presently preferred. Sciving tools can then be used to separate the strips.
Or, the adjacent edges of the strips may recover from their ~omentary displacement at all locations in the practice of certain forms of the invention, particularly where the sheet is fully slit and then immediately lightly reconnected.

If the connection after partial cutting or equlvalent is sufficiently delicate, a contoured bending bar or knockdown bar can be utilized bearlng on the faces oE the lnterconnected strlps, if desLred wlth an endless belt or belts lnterposed between the bar and the faces of the strips to elimlnate scratching and other damage to the strlps, to break the remaining bonds between adjacent strips by presslng their edges back towards a common plane or by pressing them momentarlly out of a common plane. Or sclving tools can be used to separate the strips either upon coiling after slitting or upon flnal un-coiling. Or, the daughter coils formed by the partlal sllt~ing or equivalent can be broken away from the parent coil, either simultaneously or one at a tlme, Of course~ other separating tools can also be utilized, including, but not limited to, sharpened rotary cutters slitting the connections between adjacent strips as the strips are coiled following partial slitting or at any time following commencement of coiling but before end use.

It will also be seen that under certain circumstances an additional piece of equipment for rompleting the cut may be unnecessary Thus, where the partial cutting operation results in a series oE interconnectecl strips having the still-connected portlons of their edges displaced from each other in a ~8~4~36 direction approximately perpendicular the plane of the strips, by controlling rewind tension the remaining bonds between the sheets may be fractured as they are wrapped tightly on the coiler reel. Or, the~partial cutting or equivalent may result in a connection which will maintain itself until the connected strips are bent around the winding axis, as upon winding of the connected strips, at which point fracture may occur due to the bending incident to winding. Or, the connection may satisfactorily yield only to differential unbending around the winding axis, as upon unwinding of one of the connected strips while the other remains wound. Or, the connection may or may not resist such differential unbending to an objectionable degree, but may nevertheless satisfactorily yield to imposition of spreading forces between the strips because of the "stiEf plane"
effect of the connected strips in resisting such spreading ~orces. Or, combination of such bending or unbending together wi~h such spreading may be employed, as upon unwinding by pulling the unwlnding reacll ln an unwind path that has a vector component tllat is parallel to the axls of tlle coil, or by simply tllting ~he roll axis away from the horizontill and toward or to a vertical position to thereby allow gravlty to assert such a pull. Or,~the daugther coils may be broken away from the parent coil, either slmultaneously or one at a time, without the use of special tools but simply by impact or pressure, as upon being dropped on or forced against a flat or stepped surface, or upon being struck head-on or glanclngly by an industrial truck fork or by a crane hook or the like, or slmply by sheer weight when support~by a mandrel or the like ls removed from a daughter co:LI Ln some cases where heavy coLls have relatlvely lnfrequent and/or highly weakened tacking.

The configurations of the cuts made during the partial slitting operation or equivalent are susceptible to ~ariations within the scope of the present invention. For example, the cutters can be provided with small, profiled flats ~ground into a face of the cutter adjacent its edge, thereby providing tacks or connections across the slits made by the cul:ter. Special shapes other than flats can be used to accomplish the tacking, a~ described below.

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In a variation, the cutters may be arranged to run eccentrically very slightly and adjusted vertically so that alternate complete slitting and incomplete slitting is accomplished. The incomplete slits between completely slit sections would then be separated in any of the different separating processes described above.

In another variation, the arbor of the upper cutter could be mounted ~or a slight amount of vertical movement, ordinarily on the order of a few thousandths of an inch, and cam or otherwise controlled to provide a periodic lifting of the arbor and cutters mounted ~hereon to tack across the ~llttlng each time the arbor ls llEted.

In another variation, flats on the upper and lower cutters can be brought into and out of rotative register with each other to alternately accompllsh full slltting or tacking.

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In still another variation, the cutters can be adjusted vertically so that the sheet is sheared just short of the ?oint of fracture in a continuous, uninterrupted fashion, or as called for when sensors indicate incipient or actual nonuniformity of wrap during full slitting. This alternative is applicable, for instance, when completion of separation is made during the first wrap of the coils on the coiler mandrel. Separation of the strips at the coiler can take place in any of the methods described above.

- As indicated above, instead of partially slitting, the cutters may be arranged to continuously completely slit followed however by immediate partial reconnection at a rolling station just beyond the slitting cutters so as to thus, equivalently to partial slitting, maintain the edges of adjacent pre-slit strips connected together during winding.

In the present inventlon, the slltter ancl coller oE the slltting line can be related in a new way in which relatively close coupllng between slitter and coiler exploits and, so to speak, 1'capturesl' the momentary condition of tracking in parallel which is imposed on the edges of the daughter-coils-to-be by the action of the slitting rolls. Close coupling is therefore a positive characteristic of the preferred operation of the invention.

A8 noted above, one ma~or advantage oE the partial slitting, or e~quivalent~ of the present invention is the elimination of the problem of interleaving. As also noted above, the conventional approach to this problem is the use of separators between the slit strips, which in turn necessitates the positioning of the slitter from the coiler at a considerable distance to allow the slit strips to fan out to the lateral displacement necessary to at~tain separation. Since lateral displacement is no longer necessary when slitting in accordance with the present invention, the require-ment that the slitter be spaced a considerable distance from the coiler is eliminated with a consequently much more compact process line and a resultant .
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substantial saving in floor space. The requirement of considerable spacing is not only eliminated but significant operating improvements are achieved by the converse of considerable spacing -- a close-coupled relationship between slitter and coiler. Slitting directly from a rolling mill becomes feasible, such as at the last stand of a five-stand tandem cold mill or at a temper mill.

Where final separation is performed by the end user, the elimination of individual banding and handling of separate coils is a major advantage of the invention. Instead, the original parent coil may be formed into a coil construct comprising an array of daughter coils which can be handled together until readily separated by the end user or the warehouser or other middleman.
particular advantage is the improved handling of scrap, and improved protection of coils in trans-shipment. Edge trim can be wound as disc~like coils at each end of tlle array of regular daughter coil~, rather than llavLng to be balled, chopped or wound ln ttle conventlonaL manner. The~t3 dlsc~lLlce coils then serve to protect the edges oE the enclmost regular daughter coils during shipment, and can be readily broken away at the site of coil use and, in some applications, even handled as a unit until remelted or reclaimed.

Final separation of this construct can be accomplished by individually unwinding one after another of the daughter coils which can be supported together on a single mandrel or unwinding stand to be successively (or even simultaneously) presented and fecl to a working line or lines. Or, tlle daughter coils may be broken off as units prior to unwinding. This can optionally be done with breakaway grabs carried by cranes or lift trucks or by their own carsiages or the like, so that the daughter coils can be handled by the end user in an efficient manner but in such a way as to be compatible with past procedure in handling individual coils.

, Even with the complete elimination of edge interleaving, edge overhang can occur -- a condition where a turn of a daughter coiL being uncoiled is overhung by a~radially outward turn of an adjacent daughter coil , ' '' ' ~ ~

so that interference between the edges results. A feature of the present invention eliminates this condition by "step-traaking" the daughter coils on themselves, as more fully explained below. According to another feature, edge overhang is eliminated by dishing the daughter coils. However, in the presently preferred approach in experimental tria]s, neither "step-tracking"
as such, nor dishing is utili~ed, but natural trac:king upon winding is nevertheless sufficient to entirely avoid edge overhang and provide good coil alignment with breakable interconnections between daughter coils disposed for clean shearing action as upon lateral loading of adjacent daughter coils in opposed directions.

From the above and from the following detailed description, it will be seen that the present inventlon provldes an entlrely new approach to coll slltting operations and elim:Lnates many dlfElcultles, disadvantages nnd problen~s as~oclated wltll conventional proces3e~ by not fltten~pt:Lng to ; combat these probleols, but by slmply obviatlng their source. Further advantages of the invention will appear from the following description.

BRIEF DESCRIPTION OF T~E DRAWI~GS

Figure 1 i9 a perspective view of a prlor art slitting line;

; Flgure 2 is a cross-sectional vlew on llne 2--2 oE Flgure l;

Figure 3 is a perspective view showing a slitting line in accordance with the present invention;

Figure 4 ls an enlarged cross-sectional view taken on the plane of line 4--4 of Figures 3 and 5;

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Figure 5 is a cross-sectional view taken on the plane of llne 5--5 of Figure 4;

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Figure 6 is a diagram of the momentary positions at the slitting nip of the edges seen in Figures 4 and 5 at different rotative positions of the slitting rolls;

Figure 7 is a fragmentary view of the eclge of a relieved cutter which the invention may employ;

Figure 7a shows the edge of another relieved cutter which the invention may employ;

Figure 8 is a side elevation of an array of daughter coils;

Flgure 9 :Ls a schematic fragmentary cross-sectlonal vlew, ignoring sheet crown:Lng, oE the upper leEt edge oE the coll array seen :ln Fl~ure 8 taken on the plane of the paper;

Figure 10 is a view slmilar to Figure 8 with one of the daughter coils partially removed;

Figure ll i9 a side elevation oE another array of daughter coils;

Figure 12 is a schematic fragmentary cross-sect:lonal view, ignoring sheet crowning, of the upper left edge of the coil array seen in Figure 10, taken on the plane of the paper;

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Figure 13 is a schematic side elevation, partly in section, illustrating a means for separation of daughter coils at the point of use;

Figure 13a and 13b are respectively fragmentary plan and elevational views of a part of the apparatus seen in Figure 13;

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~ 3486 Figure 14 is a schematic side elevation, partly i.n cross-section, showing an operation in accordance with the present invention where separation is completed at the coiler;

Figure 15 is a view similar to Figure 14 but showing a modlfied operation for completing separation;

Figure 16 is an end elevational view of a slitting operation showing another operation for completing separation;

Figure 17 is a side elevational view illustrating the use of the invention at the outfeed end of a tandem mill;

Flgure 18 18 a perspectlve vlew Oe a working model of the invention;

Figure 19 is a perspective view o a coil construct contemplated by the invention;

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Figure 20 i5 a fragmentary detail of Figure 19;

Figures 21 and 22 are schematic cross-sectional views taken across the stralght reach of sllt skrlp seen ln Figures 18 nncl 23 at~dlfferent points prior to the wrapping thereoE to form the coil construct;

Figure 22a is a schematic cross-sectional view ~aken across the straight reach of slit strip seen in Figure 23 prior to the wrapping thereof, but when the machine is set up somewhat differently than when it produces strip having the cross-sections schematically illustrated in Figures.21 and 22;

Figure 23 is a side elevation, partly broken away~ of the working model of the invention;

Figure 2~ is an end elevation thereof, partly broken away;

, ~8~ 6 Figure 25 is a view of a sciving tool used in the model;

Figure 26 is a side elevation, partly broken away, oE a modification of the working model seen in Figures 1~, 23 and 2~;

foreshortened Figure 27 is a schematic fragmentary/view of a slit strip or unwound daughter coil containing camber;

foreshortened Figure 27a is a/view on a smaller scale showing an elongated web of sheet material with serpentine or reversing camber;

Figure 28 is a schematic fragmentary cross-sectional view, ignoring part of sheet crowning, of/a coil array containing the strip of Figure 27;

Figure 28a :Ls a very schema~lc cross-sect:Lona:l vlew, ignoring sheet part of crownlng, oe/a coll array containlng the web oE Flgure 27a, Flgure 29 ls a plan vlew, partly broken away, of a slltting llne with automated threading contemplated by the invention;

Figure 30 is a side elevation, partly in section, taken on the plane of line 30--30 in Figure 29;

Figure 31 is a schematic cross-sectional vlew oE one form of coil breakaway devlce contemplated by the lnvention;

Figure 32 ls a slde elevatlon, partly in cross-section, of another breakaway device in the form of a coil breakaway grab;

Flgure 33 ls an end elevation of the device seen in Figure 32; and , Figures 34 and 35 are side and end elevations of another breakaway grab.

: ~ DESCRIPTION OF T~E ILLUSTRATED E~IBODI~IENTS
: For purposes of background, Figure l of the drawings cliscloses, some-what schematically, a more or less conventional sllttlng llne including an un-coillng station 10, a slltting statlon 12, and a colling stat:ion 1~. In accordance with accepted pract-lce, a coil of sheet metal or the like 16 is placed upon an unwind mandrel 18 and trained through the slitting station 1~.

1~8~486 At the slitting station upper rotary c~utters, as at 20, cooperate with like cutters, not shown, disposed beneath the strip and offset with respect to the cutters 20 to slit the incoming strip into a series of narrower strips 22. The strips 22 are then rewound on a rewind mandrel 24 and a separating device 26 including separating discs 28 serves to prevent interleaving or overhang of the edges of the rewound strips 22.

It will be noted from Figure 1, that in order to provide the necessary separation at the coiling station 14, the slittlng and coiling stations must be positioned a substantial distance from each other.

Addltionally and wlth reEerence to FLgure 2 Oe thc drawLngs, It wLlL bc notecl that tlle cross-sectlona:L conelguratlon Oe the slleet 16 varles conslderably erom an ldeal rectangular conflguration, shown ln dashed lines in Figure 2, wlth the center of the sheet actually much thicker than the edges thereof. As a result, strips cut from the center of the sheet are thicker than those cut from areas dlsplaced outwardly from the center and the center strips are, therefore wrapped more tlghtly than the outside strlps.

This results, as seen in Figure 1 oE the drawings, in the outer strips sagging between the slitter and the coiler. Although only a relatively small amount of sag ls shown in the drawings, it will be appa~ent that as the slitting and coiling process proceeds, the resulting sag will be substantial, requiring pits formed between the slitter and coller or a system of rollers for festooning the outer strips above the slittlng line.

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~ 11 of the above problems are obviated with the present invention by maintaining limited connection between the slit strips at the slitting station and completing their separation after the sheet has commenced coiling on the rewind mandrel. Thus, as seen in rigure 3 of the drawings, as sheet 16 is unwound from the mandrel 18 and trained through a slitting station 30, the sheet is predivided into strips 32 while maintaining limited connection, as indicated by the dash-dot lines 34. ThereforeJ
as the interconnected strips 32 are rewound upon l:he mandrel 36 they, in effect, behave as a single sheet.

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~ s a result, there is no necessity of maintaining separation between the edges of adjacent strips, nor do the thinner strips sag between the slitter and the coiler. As will be particularly apparent from Figure 3 of the drawings, because the necessity for lateraL dlsplace~ant oE the strips at the coller is ellmlnated the coiler ~ay be pos:Ltloned adjacent thc slltter, provLdlng a much more compact sllttlng :Llne ancl, as will be dlscussccl in detail below, rendering possible the use of a single piece of equipment for both partial slitting and final separation.

Compactness of the slitting line is however only one benefit of the relative adjacency between slitter and coller. More signlficant ls ~he achleve-ment of constraints on the strips during colling to cause them~to wlnd with almost perEect track:lng into daughter co:Lls separated by flat side Eaces. It has been discovered that momentary constralnts imposed by the sl:Lttlng cutters on the side edges of the slit strips can be "extended," so to speak, by causing the sllt strlps to behave as a single sheet (by tying the edges of adjacent :trips together, durlng or lmmedlately following slitting, as herein described), and that such con-straints can be "captured," so to speak, to be made part of the coiling operation by taking up thè slit strips on a coiler before such constraints have dissipated with continuing travel of the strips away from the slitting cutters. The result is daughter coils separated by flat interfaces through which extend the break-able ties disposed for clean breakaway shearing action. The constralnts can accomplish such flat interfaces despite the almost inevitable occurrence of camber .

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in the sheet material being sllt and despite the resultant camber in the slit strips, and even despite a slight degree of yaw in the feed roll supplying the sheet material to the slitter.

The close coupling bet~een the slitter and coiler contemplated by important aspects of the invention can be eliminated, but only at a cost in reduction of tracking accu~acy that will often be unacceptable or at least pointless.

Partial pre-slitting, or the equivalent, can be accomplished periodically or non-periodically, and intermittently or non-intermittently.
An example of periodic non-intermittent pre-slitting is the use of flats on slitting cutter~; to periodically produce tacks (upon every revolution of the cut~ers) without skippLng tacks during some revolu~ions. An example of perlodlc lntermLttent pre-slittLng Ls a slmLlar arrangelllellt Ln whlch the slittlng cutters are posltloned so that tacklng does not occ~lr, but in whicll such slltting cutters are intermittently shifted to cause periodic tacking to occur. An example of non-periodic non-intermittent pre-slitting is the pro-vision of slitting cutters which continually completely slit followed by immediate partial reconnection by the continuous or non-periodic action of rollers positioned just beyond the slitting cutters, without any lnterruption of such action of the rollers that accomplish reconnecting. An example of non-periodic lntermittent pre-slitting is a similar arrangement in whlch the rollers that accomplish reconnecting are positioned so that such reconnectlng does not occur, but in which such rollers are intermittently shifted to cause such reconnection to occur.

~ s noted above, pre-division can be accomplished in accordance with the present invention in a number of different ways. ~or example, the strip can be provided with alternating fully separated and less than fully separated sections. Separated sections of say, a few feet in length, or a few inches in length in the case of thinner material, are joined by less than fully separated sections of relatively short length. ~lternatively, the strip , 34l36 can be continuously separated and then rejoined, as mentioned above. In some applications it may be possible that the opposed cutters 31 ~Figure 3) can be provided without flats or reliefs and adjusted to provide a continuous shear line between adjacent strips 32 with the strip sheared to a point just short of complete fracturing and the fracture completed after rewinding has commenced.
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The alternative separated and unseparated areas may be produced in a number of ways, including mounting one or both of the cutters somewhat eccentrically, providing one or both of the cutters with flats or other relief shapes on their peripheries or on the faces near their cutting edges, providing a cam action or the like for adjustment of one or both of the cutters relative to each other in directions perpendicular to the face of the sheet 16. The reliefs on aacll cutter may be each insuEElclent to prevent ~ull separation alone, but capable oE dolng so LE ln reglstration with tlle relleE on the assocLated cutter, an~ the relLeEs may be brought into and out oE reglster by advanclng or retarding the angular position of one cutter relative to the other, by means of a differential drive or the like, as they both continue to rotate through the cutter nlp. Combinations of these arrangements may be provided.

~ Ll of the above arrangements for providing partial pre-slittlng, or the equivalent thereof, can be referred to as ~'tacklng" arrangements. The sll~
strips are caused to continue to move together by belng tacked together, periodically or non-periodically, and intermittently or non-intermittently.

Both periodic and non-periodic or continuous tacking involve maintaining connection between the slit strip edges sufficient to cause the slit strips to wind together. Such maintaining of connection may itself be non-intermittene or it may be made intermittent by interruptions either on a pre-programmed or on a demand basis.

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As an example of a demand control, as seen in Figure 3, sensor means 33 may be provided between the slitting station 30 and winding mandrel 36 for sensing sagging or tension differences or other differences or in-cipient differences in winding of the slit strips. The sensor may be an~
appropriate device such as a tension sensor or, as shown, a photoelectric sensor.

Cutter 31 and its companion are positioned close enough for continuous slitting until such time as the sensor 33 detects differences or incipient differences in the winding of the strips 32 whereupon the cutters are moved apart or otherwise adjusted by automatic means (not shown) sufficiently to commence maintainlng periodic tacl~in~ between the edgcs of the strlp~ 32 sufElclent to cause them to wlnd together. Thls condltlon may be termLnatcd after a glven tlme, ln tcrms of dlstance or tlme units, or may be terminated after winding differences or incLpient differences are no longer detected.

Figures 4 and 5 illustrate the configuration that may result in the region of a 'Itack" or periodic partially separated area. The ad~acent strips 32 are displaced vertically with respect to each other when they engage the cutters, and spring back together when they are fully separated. }lowever in an area of partial separation, the adjacent strips continue to be ~o ned by a bri~ge 40 oE the par~nt metal connecting .

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the metal of the adjacent coils and maintaining the vertical displacement of the adjacent strips 32 with respect to each other as seen in Figure 5, thereby maintaining an increased overall thickness of the adjacent strips (considered together as a unit) and thereby an increased overall thickness at the locations of the bridges in the turns of the array of daughter coils formed upon coiling.

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Figure 6 diagrams the momentary positions at the cutter nip of the edges a b, c d seen in Figure 4 plotted against different ~otative positions of the cutters. The rotative positions of the cutters the corresponding to passage through the nlp oE/flats on the cutters are between pos;Ltlons e and f. The vertical Locatlons g and h on the diagrnm represent thc lleLght o~ the top and bottom surfaces of the metnL shect prior to close approach to the cutter, and of the fully slit portions following passage through the cutter.

Even if only one cutter is relieved, the cutting action will be similar to that illustrated in Figure 6. Although the corresponding curves would not be exactly sym?netrical about a horizontal axis, they wou:Ld be roughly similar to the illustrEIted curves because the ad;lacent not-yet-parted strlps 32 tend to center themselves vertically between cutters even if only one cutter is relieved.

Figure 7 illustrates the relief oE a single cutter 61 designed to operate with a corresponding unrelieved cutter (not shown). The circular periphery at 62 is relieved by a flat 63 which is faired into the periphery of the cutter at ends 64 and 65.

1~84~6 V

When the metal is coiled after passing through the cutters, a plurality of daughter coils 71 are formed, as seen in Figure 8. The transverse profiles of the turns of the array comprise raised portions 72 and notched portions 73, as seen in Figure 9.
.~ ' .
The notched portions such as 73 may be slightly downwardly penetrated by a succeeding wrap of the corresponding daughter coil. Thus in Figure g each notch 73 is slightly penetrated by the first succeeding wrap 74 of its corresponding daùghter coil 75. (Similarly the second succeeding wrap may penetrate the slight gap 76 left by wrap 74, and so forth in respect of still later wraps, but the occurence of such penetration beyond the flrst succeedlng wrap is not illustrated.) CorrespondLng upward penetration may also occur wlth respect to the relie~s under the raised ~, portlon~ 72, as shown, although any such upward penetratlon wlll tend to be minlmlzed by the effect of winding tension.

The edges of the daughter coils are thereby kept in alignment to prevent edge overhang in circumstances where edge overhang might otherwise occur due to the particular circumstances of coiling. Thus as a daughter coil 71a is uncolled as ln Figure 10, there is no interference with the Eace 77 comprlslng the edges oE the turns oE the adjacent daughter coil 71b.

.
The array of daughter coils may be formed in a dished configuration as seen in Figure 11. This may be done by shifting the coiler axially ;~:, in one direction throughout the c~iling operation. Each of the daughter coils 81 and e~ch of the interfaces 86 between daughter coils is dished.
The edges of adjacent daughter coils are thereby stepped in a uniform direction, as seen in Figure 12, whereby edge overhang is avoided and no . , .
~ edge interference occurs when the daughter coils are lndividually uncoiled.
.,; ' . . . .
.
~ ~22-The arrays of daughter coils are removed from the rewind mandrel and shipped to the end user or the warehouseman or other middleman still interconnected. Final separation takes place as the strips are needed, using any of the final separating processes mentioned herein.

One particular arrangement for final cutting is shown in Figure 13. Here a daughter coil 88 is being unwound from its parent coil 89, the unwrap reach being indicated by reference number 90. In this case, to aid separation of the daughter coil, a prizing blade 91 is provided as most clearly illustrated in Figures 13a and 13b. This blade is bolted to and hel(l by a wedge finger 92 over wlllctl the un~/rap reach 90 slides an(l un(ler whLch the wouncl turns of the. claugllter coLl 88 pass. The unwrap reach 90 41 Lcles on top Eace 93 of Elrlger 92. Flnger 92 :Ls ~upl)ortecl on a flange 97 by a pivot bolt 94 provided with a spring 95 adapted to yieldingly center finger 92 in the illustrated horizontal position. Flange 97 projects from crosshead 98 which slides vertically on four columns (two of which are shown) protruding from a pair of spaced pedestal supports tone of which is shown). Raising and lowering ls done by actu~tln~cylinder 96. The underside of f:Lnger 92 can ride directly on the still wrapped portlon of claughter coLl 88.

The leading edge of prizing blade 91 may, as illustrated, depend slightly below top face 93 of finger 92, so that the blade projects partly ; into the shear line associated with the next succeeding wrap of the daughter coil to pre-initiate separation at the turn that precedes actual unwrapping or at least to~aid in maintaining the positioning of the prizi~g blade 91 immediately next to the edge of the adjacent layer of still wrapped coil that corresponds to the then-unwrapping layer of the daughter coil. In some cases such pre-initiation or position-maintaining aid is unnecessary and the depending portion of blade 91 can be omitted.

i -~3-, ~8~34~3~

The prizing blade 91 acts to laterall~ wedge or prize the top turn of the daughter coil that is being unwrapped away from the corresponding layer of the adjacent still-wrapped coil to a sufficient extent to break the remaining connection between the two. As intimated in the foregoing description, the action may be one more of wedging or priæing than of cutting.

It will be appreciated that various combinations of partial slitting techniques and separating techniques may be utilized in accordance with the present invention. For example, after partial slitting is .: .
accomplished by any of the various methods discussed above, the cut may be complete(l at any tLme aeter rewlnding has commencod by any of the method~ describe~ hereLn.

~ n another aspect of the invention, final separation may be accomplished upon rewind. As shown in Figure 14, one possible method of completing the cut formed at the slitter 30 is through the use of a contoured bending bar 38 bearing against the interconnected strips 32 just as they approach the second wrap in the coil belng built on the rewlnd mandrel 36. Because of the lncreased thlckness at'the conn~ctlng bridges, the pressure of the bar 33 bearlng against the strlps fractures the remaining bond between adjacent strLps and completes the cut ~ust before the strlps enter the second wrap of the coil. Preferably endless belts 39 are interposed between the bar 38 and the coil being bullt to prevent scratching or other damage to the faces of the strips being rewound, and the belts can ldle or be driven from pulleys 40 which are in tu~rn drlven by gears ~1 ln mesh wlth like gears 42 fixed to the arbor of the lower cutters.

_2 , J ,'' Alternatively, as shown in Figure 15,~a roller 43 can be used in place of the contoured bar 38 to complete cutting of the strips as they enter the second coil. In this regard, a segmented roller 43 can be provided having relatively larger diameter areas 44 in contact with the strips adjacent their longitudinal edges and with the larger diameters 44 interconnected by smaller diameter portions 45.

In another alternative, sharpened rotary cutters (not shown) driven by motors may simply be positioned at the rewind mandrel to complete the cuts between adjacent strips 32 after they have begun to rewind on the mandrel. Of course, the unfractured areas between adjacent strips can,part:LcuLarly where the materla'L bclng s:LLt :Ls solllcwllat brittle, l~e ~rRcturcd by s:LTnply controllLng the rew:Lnd tension.

The compactness of the s'Litting line that results from the partial slitting techniques of the present invention permits the incorporation into the partial slitting system of special slitting and separating mechanisms. Thus, as seen in Figure 16 of the drawings, sheet 16 is uncoiled from the mandrel 18 and passed through a cutting statlon 50 before being rewound on the mandrel 49. ~t the cutting station SO pairs of opposed cutters 52 and 54 are positioned above and below ~he she2t similarly to the opposed cutters 31.

However, cutter 54 includes a satellite cutter 56 at its periphery, spring loaded radially outwardly of the cutter 54. Mandrel 49 is mounted for movement in the direction indicated by the arrow 58 such that the relative positions of 'the cutter 54 and the ad~acent surface of the roll being built on a mandrel are maintained during the rewindin~ process. Thus, as the strip 16 passes between cutters 52 and 54 it will be slit into a plurality of narrower strips except at those areas where the strip 16 is contacted by the spring loaded satellite cutter 56.

-?~--~L~131!34~f~

The pressure of spring 60 is selected to be insufficient to force cutter 56 completely through the strip 16 during the pass of the strip between the cutters 52 and 54. However when the partially cut areas thus produced in the strips are again engaged by the satellite cutter 56, the now partially cut areas have been weakened sufficiently that the cutter 56 may complete the cut initiated at the slitting station 50. Because the distance between partially slit areas created by the satellite cutter 56 is a function of the diameter of the cutter 54, there is an automatic synchronization which permits the partial cut areas to be presented precisely to the satellite cutters after rewinding of the strips has commenced.

Collln~ ancl uncolllng between mllllng and partLal or total slLttlng can be avolded altogether Ln the practlce of the LnventLon.
Ln Flgure 17 partlal slltting ls accomplLshed at cutter head 100 whlch carr-les a gulde roll 102 and a palr of cutters 101 which, on a periodic basls, partlally pre-sllt the outfeed from the mill prior to coiling on the mandrel 103. The head 100 may also carry suitable conventional stripper fingers (not shown) on the infeed side of the cutters, and guide boards (not shown) on the outfeed slde immedlately beyond the stripper fingers.
The cutter head :ls moved on an inclined track lOS by cyllnder 106 as the coll i9 built to its full dlmension shown in phantom. The retractlng cylinder 107 moves the entire slitting assembly out of the way on slideways 108 when it is not to be used. The partially slit coil can be started on the mandrel by a conventional beltwrapper 109 and can be supported and removed after winding by a conventional coil car and lift 110. The stand on which the slitter is mounted may for example constitute the last stand of a five-stand tandem coLd mill. A like arrangement may be used on a temper mill constituting only a single stand. Instead of being partly s:Lit, the roll in ~igure 17 may be fully slit by completion of slitting by any of the means prevlously described as winding on mandrel 103 occurs.

34~3i In a presently preferred form of the invention, the "tacks" are not allowed to remain with the increased overall thickness as seen in Flgure 5, but are instead knocked down by passing the slit strips between a pair of knock-down rolls spaced apart a distance approximately equal to or slightly less than or, less preferably, greater than the thickness of the sheet metal prior to slitting. The bridge ~8 is thereby caused to partially shear as the adjacent slit strips at the "tack" are brought back to level with each other.
I have discovered that in at least some if not many applications the daughter coils will wind with good tracking and no edge overlapping even in the absence of the tracking arrangements described earlier herein due to the "capture" upon winding of constraints imposed by the slitting rolls on the side edges of the daughter~coils-to-be, as previously mentioned.

In one partlcular experlmental set-up lllustrated Ln Flgures 1~, 23, and 24 a steel coll 121 (Figure 23) oE .015 lnclles tlllcknes~ l~
unwound through gulde 122, rotary 3-inch slitting cutters 123, and knock-down rolls 12~ to a winding mandrel 125 driven by a motor 126 (Flgure 18) through a suitable reducer and coupling. A control handle 127 operates through the illustrated gear train to change the rotative position of an eccentric mounting for the upper cutter 123, thereby adjusting the spaclng between the cutters. Each wheel of the lower cutter 123 is provi~ed wlth a Elat as lllustrated ln Flgure 7, the Elat beLng .125 lnch Erom edge to edge and oE a max:Lmun~deptll~ (maximulll chord-to-arc spacing) of .006 inches from the cutter circumference.

The cutters 123 each may include the spaced discs or cutters proper 130, coacting pairs of which on the upper and lower cutter rolls act to shear th~e metal, and the strippers or elastomeric sleeves 131 arranged to push the sheared metal away from the shearing edges as the metal leaves the nip. A crank 132 is provided for manually driving the upper cutter 123 during set-up.

. .
.. , .~ , , .

8~

With the dimensions given, the tacking established by the flats remains sufficiently connected even after passing through the knock-down rolls to cause the slit strips to wind together into a plurality of daughter coils 140 (Figure 19) constituting a parent coil 141. In the illustrated example the two endmost daughter coils 140a constitute edge trim strip and are therefore considerably narrower than the other daughter coils. I have used pre-trimmed unwind rolls in experiments, givlng them narrow edge cuts to simulate edge trimming.

When the handle 127 is shifted to lower the upper cutter 123, tacking ceases and the slitting is continuous. The slit strips continue to track nicely as they wlnd lnto the dallghter coils belng formed. As soon a8 a sllght fluttering or looseness of one or both o the outerlllost or ncxt-to-outermost da~lghter c0119 iS detected, the handle ls rcshLEted to raise the upper cutter and re-establish tacking. The fluttering or looseness immediately disappears as the slit strips are constralned by the tacking to wind together.

Figures 21 and 22 are schematic cross-sections of the slit strips immediately downstream of the knock-down rolls. Figure 21 shows a region oE tacklng, the bridges between the ad~acent str:Lp6 being shown as more or less sbeared but rlot completely parted. Flgure 22 shows a fully sllt region.

Because of the crown seen in Figures 21 and 22, the edgeward daughter coils forming the parent coil 141 are wrapped more loosely than the more central daughter coils. However because the daughter coils are constrained to wrap together they all have the same number of turns per unit length. The "tacks" are such that the connections ..

8~ 8G

between adjacent daughter coils are contained entirely between the front and back faces or surfaces of the sheet metal. The front or back faces are not uninterrupted across the "tacks," as would be the case if slitting were entirely discontinued at the connecting regions. The opposite edge faces of adjacent daughter coils created by the slitting operation each have a continuous corner edge throughout the length of the daughter coils, including the "tacked" portions thereof.

- The "tacks" or connections between the slit strips may be established in such a manner as to seek only a minimal constraint to cause the slit strips to wind together. Thus in tlle above e~amp:Le, when elutterLng or Loosene0s of nny of the daugll~er coLLs is de~ectecl, tllc, upper cutter 123 ls not abruptLy raisecl but Lnstead the hanclle l27 15 shifted enougll to lnltlate a minlmal degree of tacking which ls usually too weak to both survlve the knock-down bars and hold the strips together until they wind on the mandrel 125. Shifting of the handle 127 is continued until the tacking is just strong enough to re-establish the constraint of forcing the slit strips to wind together.
When this contraintis established, the upper cutter may be maLntained Ln its position or, preEerably, it may agaln be lowered to repeat the cycle. Such lowerlng may be graclual an~ may be contlnued only until the looseness or fluttering is again detected. This manually controlled system can obviously be replaced by an automatic system which in effect "hunts" back and forth between a condition of being just barely able to maintain the constraintand a condition oE being just barely unable to maintain th~e constraint.

Instead of employing the illustrated flat of a depth of .006 inches, I contemplate employing coacting flats on the upper and lower cutters 123, each .003 inches deep for a similar but more sym~letric tacking . .

~884~6 .

action. In such case the upper and lower cutte~s 123 would be geared together for rotation to maintain the proper register of the flats.
The cutters 123 are not geared together in the illustrated embodiment.

For better control of tacking strength as a function of rGll adjustment, I propose to use shapes other than a flat. Thus in Figure 7a the relief ground onto the cutters by a suitable grinding roll is in the form of gullwings formed;by a pair of arcs whose points of tangency with the circumference of the 3-inch diameter cutter are .125 inches apart. The centers and radii of these two arcs are such that they intersect .006 inches below the roll periphery.
. ' .
More preEerably, two slmilarly conElgured relleEs can be provided on a pair oE cutters geared to rotate together, each relleÇ havlng an ;i arc-intersect that ls .003 inches deep.
: ' ', .
With these shapes, the cross-sectional area of the connecting bridges formed by the reLief varies with roll spacing in a more definite manner, making for more precise control. With both rolls belng relieved with such a shape, as the cutters are brought together, the mlrror-lmage "gullwings" of the two relleEs increaslng:Ly overlap to provide a diamond shape of diminlshlng slze whlch will finally disappear although presumably the degree of tacking necessary for winding constraint ; ceases before such point of disappearance is reached.
~ -. .
.

.' ' ' .

, ' ' ' ; ' ~ ' ! .

1~884~6 If one of the upper and lower cutters is advanced angularly relative to the other while they turn together with the reliefs in register, such advance has the effect of "tilting" the diamond shape. This tilt can be either "forward" or "backward" depending Otl the relative direction of the angular advance. Such relative angular advance can be accomplished by any conventional control means which allows a differential angular movement ~o be introduced between two counter-rotating rolls turning together.

The two cutters can be both moved toward and away from each other and advanced angularly relatively to each other For different tacking effects.

~ g lncreaslng Eamlllarlty with n glven slleet materlal 19 galnecl, n pre-set clegree oE tacklng n~ay be selected. A feature oE tlle lnventlon ls that the degree of cohesion between daughter coils can actually be modified, -from parent coil to parent coil, by adjusting the strength and frequency of the tacks, as for example by adjusting the slitting cutters to make the cross-sectional extent of the individual tacks greater or less, and/or adjusting the frequency of tacking or degree of intermittent operation.

In the apparatus of Figure 3 a knock-down roll 35 may be provided together wlth a similar roll underneath the strlp. With the provision of the knock-down rolls, it will be understood that the configuration of the coil wound on mandrel 36 is similar to coil 141.

In Figure 17, knock-down rolls 111 may be provided immediately beyond the cutters 101.

.

.

: . : : . ~

1~8~348~
Instead of functioning as knock-down rolls, rolls such as 124 of ~igures 18 and 23, and 35 of Figure 3, may be set by appropriate shims or the like (not shown) to a spacing about the thickness of the sheet material being slit, or preferably slightly under such thickness, and the slitting cutters may be set to slit continuously. I have found that, under at least certain conditions, when the slits pass under the rolls 124 or 35 following their formation by the slitting cutters, they are rejoined to accomplish non-perio~ic tacking. In one particular experimental set-up of the apparatus illustrated in Figures 18, 23 and 24 dead soft copper of .005 inches thickness is slit and passed between the rolls 124 which are shimmed apart by shim plates (not-shown) of .004 inches thickness to give a nominal reduction of .001 inch or 20%. ~lowever any actual reduction is difficult to observe in terms of sheet width growth, and is not believed to be significant.
The slits are tacked or rejoined by the rolling operation, and the connection appears to be stronger ln the dLrectlon of travel than in a dlrectLon perpendLcular to the sheet. Tlle rejolnlng ls not presently clearly understood and may be a pressure weldlng phellomenon or the lLke, and/or result Erom mecllanlcal ln~erengagemellt oE
burrs or the llke formed by the slitting operation. In Flgure 22a I have schematically illustrated burrs as small curved lines at the tops and bottoms of the slits seen in Figure 22a, which is a schematic cross-section o:E a sheet which has been non-periodically tacked as just described, although if burrs form part or all of the interconnection they may occur at other locations within the interfaces formed by the slits as well as or ra~her than, as shown, toward the outer extrelllltles of the lnterfaces. Such operation as described is non-intermittent since the shims cannot be changed during slltting.

In Flgure 26 I illustrate a modification of the apparatus shown in Figures 18, 23 and 24 which includes a control handle 127a which operates through a gear train, similarly to the handle 127, to change the rota~ive position of an eccentric mounting ~not shown) for the upper roll-124, thereby adjusting the spacing between the rolls 124. Such handle can be shifted from a tacking position at whlch the rolls 124 are fairly close together to a non-tacking position at which the rolls are spaced apart to thereby give an intermittent type operation. To some degree, adjustment of tacking strength may be possible by adjustment of spaclng of the rolls 124 through a range, from B~

relatively strong at relatively close spacing tovprogressively weaker at progressively less close spacing.

The interconnections between the daughter coils such as the coils 140 are breakable either by unwinding such as that described in connection with Figure 13 or by simultaneous breaking away oE all connections. In the experimental apparatus of Figures 18, 23 and 24, unwinding separation can be accomplished by removing mandrel 125 with roll 141 on it from the wind-up station, turning it end for end, and substituting it for the' original unwind mandrel (for the original unslit roll 121) at the unwind station. A single edgemost daughter coil 140, or 140a if the original roll 121 was not pre-trLmmed, i8 tralned over a wedge Lnger 13l~ pivoted on ~ slide l35 (Flgure 25) carried ln a frame 136 tFIgures 1~3, 23, 25) and through any ~uitable gulde SUCIl as the knock-down roLls (the cutters may be moved apart if in the way). The leading ends of the remaining daughter coils 140 are taped down to the parent coil 141 to prevent them from flapping and snagging. The wedge finger 134 may be thinnest at its inboard side and increase in thickness toward its outboard side, as indica~ed by the flare of the stem portion of the finger seen in Figure 25, to provide good lifting or prizing action. Unwinding may be d,one manually by pulling on the unwinding strip. As the daughter coLl unwinds, the slide 135 allows the finger 134 to follow the diminishLng periphery.
A slight drag is applied to the parent coil 140 to prevent it from overrunning. The unwinding strip breaks readily and clearly from the parent coil. Subsequent daughter coils can be similarly unwound by shifting the frame bracket in which the slot 136 is formed laterally by the width of a daughter ~oil in order to establish the proper lateral position for the finger 134. The bracket is held in adjusted position on the fixed frame by the illustrated hold-down bolts.

I have found that in many cases a prizing device such as wedge f~nger 134 is unnecessary and the daughter coils will unwind readi]y :Ln response , . . . . ......................... . .. ..
.; . . , ~ . . .
., , , . : . : :

34~6 to an unwinding pull, even that imposed only by the unsupported weight of a just-unwound reach or fall of daughter coil material.

As previously indicated, the constraints on the strips during coiling that can be accompllshed by the invention provide flat interfaces between daughter coils despite almost inevitable cambering of the sheet materlal and the slit strips formed therefrom. The camber is accommodated by variations in tightness of wrap as schematically illustrated in Figure 2~. Figure 27 shows on a reduced scale one of the strips resulting from uncoiling one of the daughter coils of Figure 28, with camber clearly present. Nevertheless, the interfaces between daughter coils are substantially planar as seen in Figure 28.
Thus, although in a general sense "tacking" according to the Lnvention causes all daughter coils to wind together at the samc unlform lenghts per unit turn de~pite varlation ln their thicknesses, there are speclflc sllght varlations from one daughter coll to tlle other of turns per unit length, such varLatlons belng a function of the degree of camber being encountered. More precisely, there are very slight differences in tightness of wrap of the opposite side edges of each daughter coil, beyond that incident to sheet crowning, just sufficient to accommodate the camber in each coil. It appears that the invention can force these slight variations in turns per unit length and these slight differences in tightness oE wrap of opposite side edges of each daughter coil to occur to ~ust the extent necessary to accomplish the substantially planar interfaces between daugther coils.

. , .
Figures 27a and 28a illustrate, even more schematically, the situation when the camber is serpentine or reversing, as may be caused for example by slight variations in the feed to the slitting cutters. In Figure 28a the interfaces between adjacent pairs of daughter coils are flat desplte the camber, and the two side edges of each daughter coil and of the parent coil incrementally along their lengths differ from each in t:ightness of wrap, .

_3~_ , ., . , ~ ,. , .. " ' , ': ' ' ': , ' : . . . ': ' ' ' : .
. ~

1~8~486 beyond the differences incident to crowning of the sheet from which the coils are formed, as a function of the degree and direction of camber of the strip material incrementally along its length. Figure 27a shows on a reduced scale the development of the coil shown in Figure 28a, illustrating the serpentine or reversing nature of the camber. In such a situation the outside ends of the parent coil may be very uneven, as seen in Figure 28a, yet the interfaces between adjacent daughter coils are flat, as shown.

Figure 28a also illustrates parts of the disc-like coilsof scrap, indicated at 3~a,that can be used to protect the edges of the parent coil in trans-shipment, as previously mentioned, and that can be broken off or unwound from the parent coil either prior to trans-shipment or by the final user. Such dlscs of scrap are not specLPically i:llustrated ln FLg~lre 3 due to the small scale tl-~ereo~.

The outer ends of the parent and daughter coils may be secured against unwindlng by being taped down to the next turn of material. For trans-shipment it may be desirable to band the parent coil through the coil core say with th~ee bands spread 120 degrees apart. The disc-llke coils 3~1aof scrap or edge trim protect against the bite of the banding.

ALthough the outslde edges of the edge tr:Lm colls may be quite irregular, as shown, the internal interfaces are flat, as also shown in Figure 28a.

A slitting line embodying novel self-threading concepts is illustrated in Figures 29 and 30. The pass line is relatively constantly horizontal. A
slitter carriage 176 is vertically movable on the posts 177 by a cylinder 178, the carrlage being further constrained in a well-known manner against cocking to one side or the other by the illustrated fixed racksand coacting linked pinions carried at each side of the carriage.

8~
The coil stands are driven by DC motors which can also act as back drag generators. The leading end of the off-feed coil 179 is slowly driven forward to be initially peeled by a retractable peeling member 180, and to be guided by a fixed rise surface 181 to pinch rolls 182. Thelower pinch roll is on a fixed mounting while the upper one is mounted on carriage 176 which is raised slightly and then lowered to accept and then tightly engage the leading end to the slitter cutters 184 of the tacking type contemplated by the invention.
~n auxiliary slitter drive including a cylinder (not shown), a vertically moving rack 185 and a spur gear 186 enclosing a one-way overrunning clutch (not shown) powers the slitters, the "threading" stroke of the rack 185 being just sufficient to advance the leading end, which is now "tacked" as will be seen below, from its point of first engagement with the slitters through the illustrated knock-down rolls and to the take-up mandrel, and into position as shown to engage or be xeadlly brought lnto engagement with the llp 187 whlch has been Eormed in a conventlonal manner by the inltially collapsed segments oE ~he take-up mandrel.
Ttle mandrel is then expanded to cause the lip 187 to grlp the "tacked" leading , end to complete threading.

The flats (not shown due to small scale) on the slitter cutters are positioned to place "tacks" at or very near the leading end of tlle strip when it first engages and is drlven through the slitter cutters. This positioning of the flats may be automatically accomplished by any suitable means, such as an Index cam (not shown) associated with one oE the slltter cutters and adapted to control a solenoid to deactivate the advance oE the actuator for the rack 185 at the proper position during an "indexing" stroke prior to the "threading" stroke previously described.

In the illustrated apparatus, the handwheel 188 may actuate a gear linkage (not shown) to control spacing between the slitter cutt:ers 18l~ and thereby control the depth of tacking and to also perhaps only apply tacking intermittently.

. ' ~C~81~348~i As slitting proceeds, a microswitch or other sensor (not shown) at corner 189 on the slitter carriage senses buildup of the coil on the take-up mandrel and actuates cylinder 178 on a demand basis. The carriage 176 thereby continues to rise during the slitting operation, and the pass line continues to be generally horizontal until slitting is comple~ed.

The off-feed coil is originally carried onto its mandrel by the coil car illustrated in Figure 30.

The ready threading just described is to be contrasted with the difficulties of setting up for conventional slitting, particularly the necessity to properly start, thread and clamp to the mandrel each separate strlp belng sllt.

~ n exyerlmelltal breakaway devlce ~or slmultalleously braal~Lng away all the connectlons o~ a daughter coll ls schematlcally lllustrated ln FLgure 26.
A parent coil is clamped on a frame 151 by a clamping member 152 releasably flxed to the frame at partlng line 156 by clamping bolts or other clamping fasteners (not shown). The endmost daughter coil is received on a mandrel 155 which is initially al:Lgned wlth the open core 150 of the parent coll.
The mandrel 155 ls eccentrlally mounted ln the frame 151 and has a squared end L53 whlch recelves a wrench 15~. Turnlng the wrench turns the mandrel 155 ln lts eccentrlc mountlng and twlsts the endmost daugllter coil relatlve to the adjacent daughter coil, causlng the endmost daughter coll to break away. The break ls clean and the points of former connection between the coils are barely discernable~ if at all. To break off a succeeding daughter coil, the clamp is loosened and the parent coil is advanced to the left by the~width of one daughter coil and reclamped.

~ breakaway grab device such as illustrated in Figures 32 and 33 can be utilized by the end user of the pre-slit parent coil in a manner that i~8~486 can be more efficient than conventional practice and require little cha~ge from conventional practice in utilizing ordinary handling equipment such as cranes or lift trucks to transport and position individual coils broken away from the parent coil. The illustrated grab includes an upper frame 161 which includes a suspension eye 162, a slideway 163 and a yoke 164. An upper gripping strap 165 of somewhat flexible material such as a flexible steel strap is pivoted on small stubs carried at each end of the yoke 164 in the manner shown.

A lower frame 166 includes a slideway 167 and an arcuate lower gripper 168. The upper and lower frames slide with respect to each other along a slideway 169. A clamping linkage including the motor 170 and screw 171 is associated with a clamp drive frame 172 received in the slideway 169 and a ~crew nut 173 received ln the slldeway 163.

The device may be suspended from a crane ln the manner shown. To break away a daughter coil the member 168 is slipped into the coil and.under the endmost daughter coil with the strap member 165 positioned just beyond the endmost daughter coil and over the next daughter coil, so that the members 165 and 168 engage the coil on opposite sides of the plane of the lnterface 174. The motor 170 is then actuated to close the clamp whereby the endmost daughter coll breaks away but rests on the member 168 wlth the outer slde face of lts upper half perhaps l.ightly engaged or at lcast retained by slight lnterference wlth one slde of the strap member 16S. The separated daughter coil can then be transported to its particular place of use by the crane and can be released by actuating the motor 170 to open the clamp to the point where the strap 165 no Ionger interferes with the outer side face of the daughter coil.

The slideways 163 and 167 allow the clamping linkage to be adjusted laterally Eor accommodation of daughter coils of different widt:hs, since it ; ~;

; -38-~8~86 is generally desirable to position the linkage as close as possible to the endmost daughter coil prior to breakaway.

Instead of or in addition to the eye 162, mounting brackets (not shown) can be provided to.fix the frame member 161 or 166 to the llfting member of a lift truck. Or any special carriage or the like (not shown) may be provided for the grab.

Another form of grab is shown in Figures 34 and 35. A pair of clamping members 191 and 192 are shaped to penetrate the core of a parent coil and engage different segments thereo~. Member 191 engages the coil at arcuate face 193 and member 192 engages the coil at arcuate face 194.
Members 191 and 192 may be tapered forwardly as shown to aid in guidin~
the lnsertion of the grab. The members are urged apart by the illustratecl hydraullcally powered frustro-conlcal wedging member 196 against the biasing o springs associated with draw rods or bolts which guide members 191 and 192 in their relative motion in the manner illustrated.

A stop member 197 deines the depth of penetration of the grab, and its position may be adjusted along a marked scale (not shown) by loosening and retightening a tie-bolt in a T-slot, as illustrated, to thereby set the depth of penetratlon oE the grab accorcllng to the thickness o the daughter coils.

Surfaces 193 and 194 terminate in slightly spaced relationship from each other so that~they may be spaced slightly to each side of the interace 198 between the adjacent segments they are grabbing, as shown in Figure 34. This reduces the criticality of the magnitude of the depth of penetration of the members 191 and 192.

.

',, ! ' . ' , . . , . . ' , .~, , ' , ' ' .. , ' ' ' ~ ' ' '' ~, " '. ' ' ' ' "
.. . . ' . , . . , , . ' '.. , ~. ' ~ ,, 1~8~86 Means (not shown) is provided to fix the back end of the member 191 to the lifting member of a lift truck, or to suspend it Erom a crane or mount it on a special carriage for the grab.

When the endmost daughter coil is broken off by expansion of the members 191 and 192, this coil remains supported on the surface 193. At this point the grab may be slightly contracted and backed out of the core far enough to clear member 192 from the daughter coil which it engaged.
The members 191 and 192 may be then expanded again, to a further clegree, until the relief surface 195 engages the core of the broken off daughter coil. The coil is now securely grasped and may be tilted :Ln handlillg, if deslred.

It may be noted that when a daughter coil is unwound from the parent coil, rather than being broken away as just described, the unwinding may be arranged to give a spreading action whereby the path of movement of the separating strip has a vector component parallel to the roll axis. (One example of such an arrangement is shown in Figure 13 and involves use of the pri~ing blade 91.) Movement along such vector cannot be accommodated by flexlng of the strip material around the axls of the roll but rather is stiffly resisted by reactlon forces actlng parallel to the axls and to the surface of the strip material. Unwlndlng arrangements involvlng a separatlng movement wlth such a vector component therefore can be very effective in subjecting the tacks to concentrated tensile stresses for good breaking action. In some instances this can be accomplished by gravi~y alone, as when a starting end of an endmost daughter coil is dropped from the lower end o~f a parent coil which is tilted toward a vertical positlon so that the startlng end continues to unwind by its own weight. I have unwound hand-held experimental coils in this manner, allowing the endmost daughter coil to rapidly unwind in a falling helix and accumulate as loose strip on the floor, with the remainder of the parent co:Ll remaining intact and the exposed side of the next-to-endmost daughter co:il remaining a smooth -~0-8~

and well-defined surface.
.
' It may also be noted that the compactness of the slitting line contemplated by the present invention increases the practicality of shielding the fast-moving slit edges for the protection oE the operator (although no such shielding is shown in the drawings). This is therefore one respect in which the invention offers substantial safety advantages.

From the above lt will be apparent that the present invention provides a fresh approach to the solution of problems associated with conventional slitting operations.

~ tlle the metho(ls nnd Eormf; o~ apparatUE~ nnd con~ltructf~ here:Ln described constitute preferred embodiments of the invention, :it is to be understood that the invention is not limited to these precise methods and forms of apparatus and constructs, and that changes may be made therein without departing from the scope of the invention.
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1~8~Li3~i SUPPLEMENT~RY DISCLOSURE

Figure 36, shows a somewhat modified form of the cutter of Figure 7a.

Figures 37 through 40 show alternative :Eorms of cutter notch profiles similar to those shown in Figures 7, 7a and 36 that may be utilized in the practice of the invention.

For better control of tacking strength I propose to use cutter relief shapes other than the chordal flat 63 as provided in the cutter 61 shown in Figure 7. Such control may be necessary in order to accommodate variations in the thickness of the sheet metal transversely of the web as i.llustrated in Flgure 2. Alternatively sllch control.tnay be des:Lrable ns wllt~n the lateral di-mens:Lon of tllc web Ls extensive, as Eor example up to as much as E:lEty-two Inches, whlch gives rlse to the posslb:Llity of deflectlon oE the arbor that mounts a plurality of slitting cutters. In each of these instances there is a possibility of significant variations in the vertical spacing between the cutting edge of the blade and the material being slit. Thus, it is desirable in a practical application of the described organization that the tack-produc:Lng relief in the slitting cutters be capable of producing interconnecting tacks o:E nearly ~mlform strength regardless oE the variations in web thickness or of the presence of sllght bowlllg of the arbor. It is furtller ~les:Lrable that the relief provided on the slitt:Lng cutters be effective to relieve the normal cutting action produced by circular slitting edge of the cutter 61 indicated as 62' in Figure 7 in a gradual manner so as to minimize the possibility of de-forming the surface of the web material adjacent the tacks in order to reduce the danger of marlcing the material surface which marking is obviously detri-mental to the finished product.

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Thus, as shown in Figure 7a, the tack-forming relief provided on the cutter 61~ is defined by a notch ground into the slitting edge of the cutter in the form of gullwings. The gullwing notch is substantially symmetrical about its midpoint, having its flanks 63' provided with a contour that is generally cycloida] in shape. The flanks 63', as shown in the figure, are convex and have a slope that increases gradually from their points of tangency 64' and 65' with the circular edge 62' of the c~ltter to the midpoint of the ; notch. This convexity of the flanks maintains the cutting angle or rake of the slitter edge and even causes it to increase toward the notch midpoint where-by the shearing of the web materiaL in the vicinity of the tack i5 clean and without material deformation that would mark the product.

AclclLt-lotlally, altllough the shnpe oE the g(lllwLnla notch shown in FLgure 7a Ls representocl n~ a "common" cycloLcl, :Lt sllouLcl ba urldarstoocl that shape~ in the Eorm of a "prolate" cyeloid as illustratecl ln Flgure 36 can also be employed.

.
It should be appreciated that these notches are symmetrical about their midpoint and possess Elanks having a slope that increases gradually from the point of tangency of the relief with respect to the circular eclge 62' oE
the rotary cutter. The convexity oE the arcuate flanks maintains the cutting angle or ralco oE the s:Lltter eclge ancl causas Lt to incraase towarcl the notch midpoLnt whereby the shearing of the web material in the vicin:ity of the tack is clean and without material deformation that would mark or distort the product.

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1C188~6 Accordingly, other cutter relief profiles having shapes comparable to the gullwing shape hereindescribed have utility in the practice of the in-vention. Such profiles are illustrated in Figures 37 through 40. The notch profile illustrated in Figure 37 is similar to the prolate cycloid profile of Figure 36 except that the Elanks 142 are formed as circular arcs and the root 143 is formed as a circular arc tangent to the arcs of the flanks. That illustrated in Figure 38 possesses flanks having a compound shape, the radially outer portion 144 being substantially cycloidal and the radially inner portion 145 being an inclined edge that extends tangentially from the outer portion.
The root 146 may be a generally flat edge that merges at each end with the inclined edges 145 by means of circular fillets 147 or, as shown in Figure 39, the root may be circular in shape, as :Lndlcatecl at 148, wLtil its opposite ends tangent to the refipectlve lncllned edges L45.

The notch o~ Flgure 40 ls similar to that shown in Figure 38 but wherein the radially inner portions 145' of the flanks are substantially parallel.

:
Also similarly configured reliefs can be provided on each pair of cooperating cutters geared to rotate together, each relief having an arc-Lntersect that ls, for example, .003 :Lnches deep.

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Claims (22)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In slitting apparatus having cooperating pairs of rotary slitting cutters defined by generally circular cutter bodies adapted to be rotatively driven, the outer periphery of each of said bodies defining mutually cooperating slitting edges engaging the opposite faces of an elongated web of sheet metal to impose a shearing action on the web material which progresses therethrough to an extent sufficient to effect severance of the residual portion of said material by fracture thereof, the improvement comprising at least one of said rotary cutters in each of said pairs containing a relief in its cutting edge, the radial depth of said relief being such that the edges defining the relief form a continuation of the slitting edge of said cutter that is operative to penetrate the web material but effective to terminate said shearing action short of the extent required to fracture said residual web portion whereby the adjacent facing edges of the slit web material are interconnected by said residual web portion.

2. Apparatus as recited in claim 1 in which said relief is defined by a chordal flat faired into the periphery of said cutting edge.

3. Apparatus as recited in claim 1 in which said relief is defined by a gullwing notch formed in the periphery of said cutting edge.

4. Apparatus as recited in claim 3 in which said gullwing notch comprises converging convex, arcuate flanks.

5. Apparatus as recited in claim 4 in which said arcuate, convex flanks are generally cycloidal.

6. A rotary slitting cutter effective in association with a cooperating cutter to slit an elongated web of sheet metal along a continuous line of shear wherein said web is completely severed along part of said line of shear and only partly severed at intermittently spaced locations along said line of shear comprising:
a generally circular cutter body adapted to be rotatively driven, the outer periphery of said body defining a slitting edge cooperable with the peripheral edge of the cooperating cutter;
means forming a relief in said outer periphery of said body, said relief being of a radial depth that the edges of said relief cooperate with the slitting edge around said body to provide an uninterrupted cutting edge around the full circumference of said body capable of penetrating the web continuously throughout the full rotation of said body.

7. A rotary slitting cutter as recited in claim 6 in which said relief is a chordal flat.

8. A rotary slitting cutter as recited in claim 6 in which said relief is a gullwing notch.

9. A rotary slitting cutter as recited in claim 8 in which the flanks of said gullwing notch comprise converging convex arcs.

10. A rotary slitting cutter as recited in claim 9 in which said arcuate, convex flanks are generally cycloidal.

CLAIMS SUPPORTED BY SUPPLEMENTARY DISCLOSURE

11. Apparatus as recited in claim 5 in which said gullwing notch is defined by flanks substantially forming a prolate cycloid.

12. Apparatus as recited in claim 4 in which said converging flanks terminate in a root formed as an arc tangent to each of the respective flanks.

13. Apparatus as recited in claim 3 in which said gullwing notch is defined by converging flanks terminating in a root, said flanks containing a radially outer portion formed by convex, arcuate curves and a radially inner portion formed by substantially straight edges that are at one end tangent to the curved outer portion and at the other end tangent to said root.

14. Apparatus as recited in claim 13 in which the straight edges of said radially inner portion are convergently inclined.

15. Apparatus as recited in claim 14 in which said root is formed as an arc tangent to each of the respective straight edges.

16. Apparatus as recited in claim 13 in which said root is a generally flat edge joined to the respective straight edges by tangent curved edges.

17. A rotary slitting cutter as recited in claim 10 in which said gullwing notch is defined by flanks substantially forming a prolate cycloid.

18. A rotary slitting cutter as recited in claim 9 in which said converging flanks terminate in a root formed as an arc tangent to each of the respective flanks.

19. A rotary slitting cutter as recited in claim 8 in which said gullwing notch is defined by converging flanks terminating in a root, said flanks containing a radially outer portion formed by convex, arcuate curves and a radially inner portion formed by substantially straight edges that are at one end tangent to the curved outer portion and at the other end tangent to said root.

20. A rotary slitting cutter as recited in claim 19 in which said straight edges of said radially inner portion are convergently inclined.

21. A rotary slitting cutter as recited in claim 20 In which said root is formed as an are tangent to each of the respective straight edges.

22. A rotary slitting cutter as recited in claim 19 in which said root is a generally flat edge joined to the respective straight edges by tan-gent curved edges.