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Publication numberUS3655475 A
Publication typeGrant
Publication dateApr 11, 1972
Filing dateMay 26, 1969
Priority dateMay 26, 1969
Publication numberUS 3655475 A, US 3655475A, US-A-3655475, US3655475 A, US3655475A
InventorsSiegal Burton L, Stelling Walter R Jr, Talbott Michael M
Original AssigneeOrbitex Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of and apparatus for making honeycomb core
US 3655475 A
Abstract
A web of thin flexible material such as resin-impregnated cloth suitable for making expanded honeycomb core structures is drawn from a roll, the web being somewhat more than twice the width of the lay-up which is intended to be made. The double web passes through a printing station at which only one face has transverse lines of adhesive imprinted thereon. Each line extends only half-way across the web, and the lines on one half of the web are staggered along the length of the web with respect to the lines on the other half by a constant spacing. The web is slit into two halves, each being approximately one half of the width of the original double web. From the cutting station the two half webs pass over a pair of spaced turning bars which change the direction of movement of the respective half webs so that they are aligned edge to edge but with both printed faces in the same orientation so that the face of the bottom web engages the back of the top web.
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Description  (OCR text may contain errors)

[15] 3,655,475 1451 Apr. 11, 1972 Primary Examiner-Benjamin A. Borchelt Assistant Examiner-G. E. Montone Attorney-Silverman & Cass [57] ABSTRACT A web of thin flexible material such as resin-impregnated cloth suitable for making expanded honeycomb core structures is drawn from a roll, the web being somewhat more than twice the width of the lay-up which is intended to be made. The double web passes through a printing station at which only one face has transverse lines of adhesive imprinted thereon. Each line extends only half-way across the web, and the lines on one half of the web are staggered along the length of theweb with respect to the lines on the other half by a constant spacing. The web is slit into two halves, each being approximately one half of the width of the original double web. From the cutting station the two half webs pass over a pair of spaced turning bars which change the direction of movement of the respective half webs so that they are aligned edge to edge but with both printed faces in the same orientation so that the face of the bottom web engages the back of the top web.

30 Claims, 7 Drawing Figures ....B3ld 3/02 Budwig.............................,156/197 X ....l56/548 X Ballard................ ...156/512 X 7/1962 Wentworth et al. ...156/197 Bova et a1..............................156/197 United States Patent Stelling, Jr. et al.

[54] METHOD OF AND APPARATUS FOR MAKING HONEYCOMB CORE [72] Inventors: Walter R. Stelling, Jr., Wauwatosa, Wis; Burton L. Siegal, Skokie, 111.; Michael M. Talbott, Key Biscayne, Fla. [73] Assignee: Orbitex, Inc., Miami, Fla.

[22] Filed: May 26, 1969 [21] App]. No.2 827,781

[52] [51] Int. [58] FieldoiSearch..........................

[56] References Cited UNITED STATES PATENTS 412 7/ 1904 131 8/1953 Lincoln...

PATENTEDAPR'II I972 3.655.475

SHEET u UF 4 Xmrim Z .Fzlega METHOD OF AND APPARATUS FOR MAKING I-IONEYCOMB CORE BACKGROUND OF THE INVENTION 1. Field of the Invention I The invention herein relates generally to the field of manufacturing honeycomb core for use in fabricating honeycomb core structures. lt is concerned with the process and apparatus which produce the so-called lay-up just before expansion, such lay-up being a stack of sheets of flexible material properly oriented so that the lines of adhesive are arranged to produce the characteristic sixssided honeycomb cells when the stack is thereafter adhered to form a block and then expanded.

' The older methods of making honeycomb core material used webs that were imprinted with adhesive along their lengths so that the printing rolls were made as cylinders having circumferential parallel annular printing rings and the adhesive lines were parallel with the side edges of the web. Many methods of printing and handling webs were used, but the result was the same. The web is cut into equal lengths and these are laid on top of one another, but the lines of adhesive between each pair of facing sheets must be staggered with respect to lines of adhesive between either one of these sheets and the face of the succeeding sheet opposite. To be more explicit, and considering a group of sheets which may be designated A, B, C, D etc., on top of one another, the lines of adhesive joining sheets A & B, C & D, E & F, etc., all lie on top of one another in perfect alignment. The lines of adhesive joining the sheets B & C, E & E, F & G, etc., also lie on top of one another in perfect alignment, but are located between the lines of the former group. In other words the lines of adhesive on opposite faces of any sheet are staggered. The lines of adhesive in the honeycomb core material are known as node lines.

When a block of sheets so adhered is pulled apart, assuming properly chosen dimensions for the width of the adhesive lines and their spacing, there will result substantially perfect honeycomb cells, each of which has two oppositely parallel sides formed of adhesive lines secured to other cells, and the remaining four sides being free of face to face attachment.

As known, the resulting structure has great strength in the direction T, which is perpendicular to the cells and has been used for the core of aircraft and missile members, in furniture, doors and in many other structures. The materials from which honeycombcore is made comprise aluminum and steel foil, paper, resin-impregnated fiberglass cloth, and other flexible fibrous sheeting. In large structures it is desirable to have the ribbon dimension L of the honeycomb core material as uninterrupted as possible without the need for piecing sections together. This gives greater strength to the resulting composite structure. The ribbon dimension L is the general direction defined by a single sheet of material transversely of the cells but in the direction of the undulations forming the cells. Thus, for example, in the case of lengthwise printing of adhesive, the node lines will be formed along the length of the web, the cells will have their axes also along the length of the web, but the ribbon dimension L will be transverse of the web. Accordingly the maximum ribbon dimension for a given block of expanded honeycomb (called a log in the trade) is the width of the web from which it is made. The W, or width dimension is also at right angle to the cells, but also normal to the ribbon dimension. The honeycomb core has less strength in the W'dimension than the L dimension.

In the case of transverse printing of the adhesive lines, the resulting node lines will be transverse of the log, and the ribbon dimension L will be along the length of the log. The T dimension is determined by the width of the web, and this is normally very small because of the thickness of members eventually made. There is no limitation to ribbon dimension L other than the practical problems of handling materials of great length.

Others have realized the benefits of transverse printing, but thus far the methods and apparatus for utilizing the technique are not efficient and economical. Aside from the normal problems of controlling the side lay and registration of webs passing through printing machinery, the problem of accurately laying the lengths of cut web material one on top of the other to produce a proper lay-up has been difficult to solve. Various schemes of interleaving, cutting successive or alternate sheets, and the like have been attempted. These require expensive and complex apparatus, special formulas to be used in computing the proper lengths, etc.

The invention contemplates a simplified and effective method of and apparatus for producing the lay-ups for making honeycomb core material which are based upon the use of a single, wide web that is imprinted with two patterns side by side, these patterns being accurately related so that when the two webs arecut at the same point and placed on top of one another there will be accurate staggered orientation of the adhesive lines with respect to one another. The exact nature of the invention will be described hereinafter.

2. The Prior Art It is known to print adhesive lines transversely of a web of flexible material to obtain the benefit and advantages of the longer ribbon dimension.

The following patents disclose this well-known concept:

Lincoln U.S. Pat. No. 2,649,131; May U.S. Pat. No. 3,074,839; Knoll et al. U.S. Pat. No. 2,983,640; and Bova U.S. Pat. No. 3,242,024.

Engel U.S. Pat. No. 2,609,315 discloses the concept of making honeycomb core material in which the web is corrugated prior to adhering to other webs, the corrugations being transversely of the length of the web.

SUMMARY OF THE INVENTION The invention herein is characterized by the processing of a double web as opposed to the prior art processing of single webs. The adhesive line pattern is printed on a double width web with the lines of the respective patterns staggered. Each pattemhas a line of perforations along one edge thereof the perforations being paired on the respective patterns and precisely located, but not necessarily being geometrically disposed with respect to each line of the patterns. In this way the same perforating mechanism may be used for different cell cizes.

In the double form and with the perforations, the web passes through a drying oven where the printed adhesive is dried to a temporary non-adhering condition, and then if desired, the web passes through some cooling means, such as for example, between chilling rolls. Thereafter, the web is led through a slitting station using, preferably, a pair or pairs of rotating cutting wheels. One cut divides the web in half along its central length and another cut trims off the edge. This is done to provide cut sheets with some reference edge so that variations of the actual transverse dimension of the web will result in a minimum of out of register sheets in a given lay-up.

Following the passage of the double web through the slitting station, the respective halves are separated angularly, that is, along diverging planes but without lateral separation so as to eliminate strain on the respective webs. In the preferred embodirnent, each half web passes over a turning bar which is arranged at an angle, the turning bars being spaced apart vertically but being arranged at substantially the same orientation to that the two half webs which leave their respective turning bars will be in lateral alignment, but, spaced one above the other. One of the half webs is adjusted in length by means of a suitable compensator mechanism and thereafter joins the other web substantially in registration therewith, the double thickness presented by both half webs being passed through a pair of draw rollers and into a sheeter. The sheeter includes a rotating knife that cuts the sheets simultaneously into any.

predetermined length, the length being chosen so as to provide a repeat length which will besynchronized with the location of the perforations, the perforations by this time being substantially in alignment. The sheets are accumulated in a suitable container, and when a sufficient number has been accumulated, the sheets are lifted out of the container and spindled onto a single pin provided on a board driven by a jogger or onto a plurality of pins. A guide is used to cooperate with the jogger to stack the sheets and thereafter the stack may be clamped and moved to further processing.

In anotherform of the invention, one of the half webs is led over a pair of turning bars which are spaced apart to lead the said half web to a disposition overlying the other unturned half web so that both may proceed together through the sheeter on the same path as the unturned half web.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is perspective diagrammatic view in highly simplified form showing the apparatus used in practicing the method of the invention.

FIG. 2 is a diagrammatic top plan view of the jogger of FIG. 1 with a lay-up of cut sheets in place thereon.

FIG. 3 is a fragmentary top plan view of a section of web taken approximately at the location of the arrows 2-2 of FIG.

FIG. 4 is a fragmentary sectional view diagrammatically illustrating the upper left hand corner of the stack being formed on the pin of FIG. 2.

FIG. 5 is a fragmentary perspective view of a portion of the apparatus of FIG. 1 but illustrating a modified form of such apparatus.

FIG. 6 is a top plan view of the structure shown in FIG. 5.

FIG. 7 is a fragmentary diagrammatic view of apparatus for performing a modified method in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic method of the invention depends on performing some of the important processes while the web of flexible material is twice as wide as the eventual lay-up. This gives rise to efficiency and economy as well as ease of handling. Registration problems are substantially decreased and uniformity is fairly well assured.

The reference character 10 in FIG. 1 designates generally apparatus for carrying out the invention. It will be appreciated that respective portions of the apparatus are well known as to their general construction and characteristics and it will also be appreciated that certain devices which are used in handling webs and printing on them are not illustrated. These will be pointed out.

A roll of flexible sheet material is illustrated at 12 and this is shown mounted on a suitable shaft 14, being arranged to have a double width web 16 unwound therefrom. The shaft 14 symbolically represents any type of unwinding apparatus which will support the roll 12. The material which is capable of being used in any of the fabrics or foils from which honeycomb core structures are made and will include aluminum foil, woven glass fabric impregnated with resin, and the like. One advantage of the invention resides in being able to use large rolls which do not necessarily require pre-slitting with resulting waste before use.

The raw web 16 passes through suitable guiding and feeding means such as for example represented by the rolls l8 and 18' to the printing station 20. Such guiding and feeding means may comprise a series of idler rollers 18 for stabilizing the web being stripped off the unwinding apparatus 14 and a series of driven in-feed rollers 18'. Combinations and variations may be used. The drive for the in-feed rollers is synchronous with the drive means for other parts of the apparatus 10. In the description of the apparatus hereinafter reference will be made to other guide rolls which assist in moving the web through the apparatus 10. It will be appreciated that the illustration of guide rolls in FIG. 1 and in FIG. 5 and 6 is merely diagrammatic, such guide rolls symbolizing some means for leading and directing the movement of the web. Any apparatus handling long lengths web will have various types of guiding means and hence it is to be understood that the illustration of rolls and their locations is not intended to be limiting or to designate any specific guide means.

At the printing station 20 the raw web 16 has a pair of patterns imprinted thereon. These patterns will be described in detail shortly. The printing station may include a well 22 having a pickup roller 24 applying a suitable adhesive which is carried in the well 22 to a printing roller 26. A doctor roller or blade 28 wipes the surface of the printing roller 26 after which the surface engages the bottom of the raw web 16 and by virtue of the back-up roller 30 applies the patterns to the raw web so that a double width imprinted web l6-P emerges from the printing station 20. The double width printed web 16-? passes to a perforating station 32 at which the web l6-P is perforated by a suitable punch and die arrangement. For purposes of simplicity there is illustrated a roll 34 having punches and a second roll 36 having the so-called dies into which the punches telescope so that the web passing out of the perforating station 32 is now printed and perforated. The web is thus designated 16-PP. Such web is shown passing over successive guide rolls 38 and 40 to enable its direction of movement to be changed and then passing through a drying station 42.

The perforating station 32, according to the embodiments of the apparatus and the method thus far described in connection with FIG. 1, is required to handle the printed web 16-? on which the lines of the adhesive are still wet. This does not pose a problem for certain apparatus but, in case it does, it is simple matter to dispose the perforating station 32 before the printing station 20, such as for example at the location designated 32. Thus, the wet printed web emerging from the printing station will also be perforated, and the raw web 16 entering the perforating station 32' will be dry.

In respect to the type of adhesive and the nature of the printing roll 26, for the production of accurate adhesive lines it is preferred that a gravure method be used. The roll 26 adhesive lines therefore is engraved or etched with the desired pattern, the doctor device 28 wipes off the excess adhesive from the surface of the roll 26 and the back-up roll 30 actually presses the bottom of the web 16 against the surface of the roll 26 so that the adhesive is picked up out of the liens engraved on the print roll 26. This method of printing is called direct gravure and provides the best results for the honeycomb core material being made according to the invention. Other printing methods may be used.

Referring now to FIG. 3 there is illustrated a short length of the double web 16-PP occurring for example at the location 2--2 of FIG. 1. But for the fact that the adhesive lines are dry at the location 2-2, there is no visible difference in appearance of the web between the perforating station 32 and the slitting station 44. The slitting station will be described below. The web length shown in FIG. 3, has been referred to as a double width web printed and perforated. There are two patterns printed on the web l6-PP each pattern being a series of lines of adhesive which eventually will form node lines. The pattern 46-A is identical to the pattern 46-B with the exception that the individual lines of adhesive do not extend uninterruptedly across the web 16-PP. Importantly the track for the perforations must be clean, in almost all cases, to prevent adhesive from interfering with the perforating means. The lines 48 of each pattern are identical in length, thickness, width and spacing and are staggered with a precise half-pitch spacing so that if the web 16-PP is slit up its center on a line 50 and the webs placed on top of one another without changing the longitudinal orientation of the lines, the lines of the adhesive of the one half of the web will lie exactly between the lines of adhesive of the other half. This will be appreciated from an examination of FIG. 4, although FIG. 4 relates to the spindling of the cut sheets to be described. The requirement of alternate lines of adhesive to form the node lines between sheets which will be pulled apart to produce honeycomb is well-known and fully described in the prior art. The dimensions of the primed lines of adhesive and their relationship to one another are chosen to produce cells of six-sided configuration. All lines 48 have the same ribbon dimension 52, the same pitch 54 being chosen so that when sheets are adhered together the adhesive lines 48 will produce the nodes and the spaces there between will produce the single thickness unadhered portions of the honeycomb cells. Due to practical considerations and geometry, the distance 56 between the printed lines 48 of the pattern is not exactly equal to three times the L dimension 52 of the printed lines.

As for the length of the lines 48 considered transversely of the web 16-PP, it will be seen that such length 58 will be the same for each pattern. There is a line of perforations 60-A on the web half A, the centers of such perforations 60A being on a line 62-A spaced from the line 64-A which represents the left hand ends of the adhesive lines 48 of the pattern 46A. Likewise, the right hand half of the web l6-PP has similar perforations as 60-B lying on the line 62-B spaced from the line 64-B by the same amount as the spacing between the lines 62-A and 64-A. The perforations occur along clear tracks, preferably.

The perforations 60-A and 60-B are identically located on each half of the web 16-PP so that each perforation forming a pair, that is, with one on the right half and one on the left half, lies at the same identical point along the length of the web l6-PP. This is indicated by lines 60-C. The perforations are spaced equally apart along the length of the web by the pitch distance indicated at 66 this being chosen so that there will be a repeat pattern coinciding at some point with identical appearance of the repeat pattern of the printed lines 48. This can be done by suitable choice of the dimensions of the printing roll 26 and the dimensions 52, 54 and 66.

Referring once more to FIG. 1, the moving web 16-PP passes through the drying station 42 where the adhesive is dried to a substantially non-adhering condition. This is so that the sheets may be handled and stacked without difficulty of adhering, since there are adjustments which normally would be made by moving sheets relative one to the other during the process. Resinous adhesives are preferred since these may be dried temporarily, and the adhesive later activated by heat and/or pressure. 1

The web l6-PP emerges from the drying station 42, passes over a guide roll 70 to the slitting station 44. If desired, the web l6-PP may be cooled after it emerges from the drying station in a cooling station 72 by passing the same over so-called chill rolls 74 which have circulating coolant as shown at 74'. The web 16-PP may also be cooled by air if desired or even handled without further cooling prior to entry into the slitting station 44.

At the slitting station 44 the web l6-PP passes around draw and/or pinch rolls 76 to the slitting means 78. Two rotating knives 80 and 82 are shown in simplified form co-operating with a backup structure 84, these knives serving to cut and trim web 16-PP so that when the web emerges from between the draw or pinch rollers 86 it is comprised of a left hand web l6-PP-A, a right hand web 16-PP-B and a small strip of waste l6-PP-W which is trimmed off during the process and passes into a suitable receptacle 88.

Referring now to FIG. 3 once more, it will be noted that the lines of cutting by wheels 80 and 82 are designated by 90 and 92 respectively. It will be recalled that the half web dimensions A and B were said to be substantially equal. It is preferred that the cut lines 90 and 92 comprise the reference edges of the resulting sheets so that the effects of any drift in the lateral position of the web 16 as it passes through the apparatus will be minimized. This will become apparent when the description relates to the matter of making the layup. Sidelay apparatus: mechanical, electrical, hydraulic, pneumatic and combinations thereof; are known, and commercially available for controlling the accurate passage of the web 16- PP through the apparatus 10 without substantial lateral drift.

From the slitting station, the two webs 16-PP-A and l6-PP-B separate along two diverging planes which are at an angle to one another but without changing the lateral reference of one web to the other. The inside edges 92 and 92' of the separating webs both lie in the same flat plane that is normal to the axes of the last guide roll engaging the webs after slitting. In FIG. 1 these would be the draw or pinch rolls 86. This arrangement prevents lateral strains on either of the web halves 16-PP-A and 16PP-B.

The next step in the method of the invention and which is required to be performed by the apparatus is to bring the two webs together in face to back relationship and with the printed surface of one web engaging the blank surface of the other. This is done at a turning station 93, there being a pair of turning bars 94 and 96 at such a station. These bars may be any known structure, and in the preferred device they were highly polished, fixed, generally cylindrical members arranged atan angle with respect to the approaching webs l6-PP-A and l6-PP-B and spaced apart vertically. In this instance the resulting half-webs 16-PP-A and l6-PP-B after turning, were both approximately as with respect to the direction of movement prior to turning, but this is a matter of choice since the webs can be turned by means of such turning bars to come together in any direction of movement. Each web half passes over its respective bar and as emerging from the turning station 93, the printed patterns are on the bottom as shown in FIG. 1. Thus, the lines of perforations are on the left of the web as shown at 60-A and 60-B. The web 16-PP-A is the bottom one. The web halves may be turned right or left, as desired, and either may be on top or bottom.

In order to compensate for any difference in total length of the respective webs from the slitting station 44 to the sheeter 98, a compensation device 99 conveniently may be provided operating on one of the webs. In FIG. 1 the web l6-PP-A passes from its turning bar 96 to the laminating guide roll 101 directly. The half web 16-PP-B however, first passes around a guide roll 102 whose shaft axis is fixed and then over a compensating roll 104 which is adjustable bodily by having its axis vertically movable so that a loop 106 is formed in web 16-PP-B. This loop may be increased or decreased as desired to bring the two webs 16-PP-A and 16-PP-B into substantial registration by the time both of them pass around the laminating roll to the pinch and draw rolls 108. These two latter rolls may be considered a part of the sheeter 98.

At 109 there is shown in block form an apparatus which may occur prior to or after the pinch rolls 108 and having a cable 111 which is shown extending to control means. In operating the compensating device 99 the roll 104 is raised or lowered. This can be done mechanically by a workman watching the perforation registration after the half webs come together, either between the roll 100 and the pinch rolls 108, or at the location where the device 109 is shown in FIG. 1. Preferably this can be done photoelectrically. The device 109 directs a beam of light through the perforations and two photo-responsive transducers receive the light in substantially equal amounts when the perforations are aligned. The overlap of perforations results in one or the other receiving more or less light. Suitable electrical equipment energizes means to move the roll 104 up or down. This type of equipment is known. The control may also be coupled to operate the rotating drum 1 10.

The sheeter is intended to cut the now doubled web 16-PP-A-B into sheets of pre-determined length. There is illustrated a simplified rotating drum 110 having a radial knife 112 that cooperates with a backup roll 114 so that each rotation of the drum 110 will produce a cut transversely of the double web l6-PP-AB enabling the resulting pair of sheets to be drawn through the discharge rollers 116 and be discharged into the movable bin 118.

All of the important rotating parts of the apparatus 10 are suitable synchronized by means of drive mechanisms which are driven from a common power source (not shown). Thus for example, infeeding, printing, perforating, slitting and sheeting will have the rolls for the most part driven by connection gears, chains, and the like. In the case of the sheeter, the

pull rolls 108 would be driven at slightly greater than the same speed that the other rolls are driving the webs to maintain tension thereon. This may be true likewise of the rolls 116. As for the drum 110, its speed is controlled by a variable speed mechanism (not shown) controlled by the operator or automatically so that it revolves at such speed relative to the rate of passage of the double web 16-PP-AB to give the desired length of sheet.

The sheeter is arranged to cut at a repeat length that will provide the same end edge relationship to the respective patterns 46A and 468 on every sheet coincident with the occurrence of a repeat relationship between perforations 60-A and 60-8 at the same location. This assumes nominal registration of perforations. Thus, the perforations resulting at any place along the pair of sheets will enable the sheets to be properly aligned for making the necessary lay-up.

When a sufficient number of pairs of sheets has been accumulated in the bin 118, the stack such as indicated at 120 is transferred to the board 122 of a jogger 124. Preferably, the bin 118 is on small casters 126 arranged to roll along guide rails 128 maintaining the bin at an angle downwardly away from the sheeter so that the sheets emerging from the sheeter 98 will drop by gravity into the bin 118. When filled, the bin is simply rolled into the position shown at 118' and a new bin placed at the location to receive the discharged sheets so that the apparatus 10 need not be interrupted for any substantial time.

The jogger 124 vibrates the stack 120 to align the sheets. In FIG. 2 the jogging board 122 is shown, this being at an angle with the horizontal of approximately 5 to and having a lower guide member 130 along one edge At its upper left hand corner, the jogging board 122 has a perpendicular spindling pin 132, this being located to engage one of the end, or close to end perforations of the stack of sheets 120. The lower reference edges 92 and 90 are aligned against guide 130.

In removing the stack 120 from the bin 118 as viewed in FIG. 1, since the sheets have their upper faces blank and the perforations 60-A and 60-B are on the left as viewed in that figure, it is convenient to rotate the stack as it is removed and as indicated by the arcuate arrow for spindling operation. After the stack has been built up on the jogging table 124 it is clamped or otherwise secured together or could even be removed with the board 122 bodily to provide the completed block or stack of unexpanded honeycomb illustrated at 136.

The flipping of sheets as described is to ensure that no pairs will be split, as might be the case if sheets were removed and stacked elsewhere erectly. It is not essential to use the rolling bins 118. One could have a jogger right at the discharge of the sheeter and build the stack 120 right at that point. Also where the automatic control gives good perforation register, one could easily stack by using a bin having a plurality of stacking pins, instead of the scheme described, which uses a combination of one pin 132 and a guide 130 engaging the reference edges 90 and 92.

This stack or block is placed under pressure, passed into an oven and heated so as to activate the adhesive and cure the same after which the stack is expanded by any suitable or well known mechanism. Expansion will be effected vertically but obviously the stack may be otherwise oriented during expansion relative to the stack shown in FIG. 2.

Assuming the top sheet in FIG. 4 to be one of a pair cut by the sheeter 98, and realizing that the stack 120 has been turned up side down to spindle the same, it will be seen that the top sheet in FIG. 4 is derived from the web 16-PP-A, the next sheet from the web 16-PP-B and so on and it will also be noted that each of the sheets has the adhesive lines 48 thereon staggered when compared to the adhesive lines on its adjacent sheet.

Considering FIG. 2, it should be appreciated that if there is a slight difference between sheets in their widths because of slight lateral departure of the web from its normal line of passage through the apparatus 10, that amount in a stack 120 will be negligible, because as seen the dimension 62A to 90 is always substantially equal to the distance between 628 and 92 even where the web drifts. Gradual drift will not substantially change the register in the ribbon dimensions any appreciable amount. Each sheet is rotated around its upper left hand comer so that both reference edges and 92 are engaged against the guide member 130. There will be substantially no variance in length between each of the sheets forming the pair since they are both being cut by the sheeter simultaneously.

The apparatus described thus far is conveniently used where the available floor space permits the equipment being arranged substantially at an angle. In other words the sheeter 98 has the web l6-PP-AB passing through it on a line which is substantially perpendicular to the line of movement of the webs passing out of the slitting station 44. An establishment where the apparatus is located may prefer that the line along which the webs move be rectilinear beginning to end and in such case the structure of FIG. 5 may be used.

In FIGS. 5 and 6 the webs 16PP-A and 16-PP-B are shown on the right emerging from a slitting station 44 (not shown in this view) and passing under a guide roll 86 after which they diverge vertically. Again the edges 92 and 92 lie in the same vertical plane, but in this case the web 16-PPA continues along the same line of movement to the sheeter (not shown) by way of the laminating guide roll 101. In this view the compensating mechanism is not shown for simplicity. The web 16-PP-B however, passes over two turning bars which are here designated 94' and 96 whose purpose it is to move the web 16-PP-B laterally so that it lies directly on top of the web 16-PP-A. The turning bars 94 and 96' are arranged at an angle and vertically spaced and it is believed that their function in effecting the result desired is obvious.

Each pattern may have different forms of indicia as at -A and 100-B to assist in visual identification to assist in identification of side by side half-webs for a multiplicity of maintenance and adjustment purposes.

It will be appreciated that the apparatus illustrated will normally have structure well known in the trade that is common in the handling of moving webs. Electronic registration and compensating mechanism can be used, but according to the invention are not essential. Since the two halves of the web are printed side by side and perforated side by side, the spindling on both perforations of an exactly located pair of opposite perforations is bound to produce substantially perfect placement of the printed patterns staggered with respect to one another exactly as printed. By choosing the proper repeat pattern at which point the sheeter 98 cuts the sheets lengthwise, registration of the lines is assured from pair to pair when the pairs are stacked onto the spindling pin 132.

The apparatus and method which have thus far been disclosed relate to a web which is imprinted on one face and unprinted on its back surface. Two variations of this scheme are worthy of mention.

In one example, the pattern 46A is imprinted on the one half of the face of the web while the pattern 468 is imprinted on the other half of the back of the web. The dividing of the web and directing the two halves to move into face to back engagement is accomplished in this instance by folding the web up its center and swinging the two halves into surface to surface engagement about the fold. The nature of this method will be understood from a study of the discussion above, and apparatus for accomplishing the same is capable of being devised by those skilled in this art.

The second example utilizes a method and apparatus which will vary from those methods and apparatus detailed above by little. In this case, quite simply, the patterns are printed on both sides, a blank web is laminated to one surface prior to perforation and the laminated two-ply web being thereafter treated exactly as a single ply web. In FIG. 7 the apparatus 200 has a first roll of flexible material at 212 on an unwinding apparatus 214 and providing a web 216 passing through guide roller means 218 and in-feed rolls 218' to the printing station 220. In this case there are two fountains 222, two pick-up rollers 224, two printing rollers 266 two doctor rollers 228 and two back-up rollers 230. This arrangement will print patterns on both faces of the single thickness web 216 and the patterns will be exactly as described in connection with FIG. 3, but staggered front and back. In other words, the pattern on the back of the half that carries the face pattern 46A will be staggered but identical thereto, and hence identical in length-wise disposition with respect to the pattern 468. The pattern on the back of the half that carries the face pattern 463 will be staggered but identical therewith and hence identical in lengthwise disposition with respect to the patterns 46A.

The two surface printed web 216 is now passed through laminating rollers 231 where it is laminated to another web 217 which is derived from a second roll 212' passing through guide roll means 218" and in-feed rollers 219. The laminated web passes through a perforating station at 232 which is identical to the station 32. After emerging from the perforating station 232, the laminated web has the same characteristics as the web 16 described as 16-PP, that is, it has a pair of staggered patterns on one face and is blank on its rear surface or back. It can thereafter be passed through a drying station, chill rolls, slitter, turning station, etc. and handled exactly as though it was made out of a single ply of flexible web material. When finally discharged from the sheeter, each pair of sheets will actually comprise a total of four plies, but the resulting product will be no different than if it comprises two plies. Thus reference to a blank surface does not exclude a web having a ply of flexible material covering a printed pattern and presenting an outward unprinted appearance. An additional drying step may be required as shown at 270 between the printing stations, to prevent wet adhesive from interfering with the operation of the second printing station, but this depends on the adhesive characteristics. Likewise the lamination could be done to the already printed side between printing stations, which might eliminate the need for drying at 270, leaving the full drying step for a later point in the process.

Modifications in the method and apparatus may be made without departing from the spirit or scope of the invention as defined in the appended claims.

What it is desired to be secured by Letters Patent of the United States is:

1. The method of making honeycomb core structure in a stack suitable for further processing by at least expanding the same, which comprises:

A. imprinting parallel lines of adhesive transversely of an elongate substantially continuously moving web of flexible material suitable for making honeycomb core structure, said parallel lines i. being imprinted as two spaced side by side patterns, each pattern being continuous along the length of the web, occupying substantially half of the lateral width of the web, and being disposed only on one face of its respective half width with the back of said half width being unprinted,

ii. each pattern having its lines staggered with respect to the lines of the other pattern along the length of the web,

B. dividing the web substantially along the center to form two half webs each provided with one of said patterns only on one face thereof,

C. directing the two half webs angularly one relative to the other divergingly and then convergingly' to move same into surface to surface engagement one over the other with the pattern carrying face of one half web engaged with the unprinted back of the other half web but maintaining the said staggered disposition of the lines of one pattern with respect to the lines of the other pattern substantially unaltered,

D. cutting equal lengths of the two webs simultaneously at a predetermined repeat location to provide pairs of face-toback sheets of said flexible material of substantially half the width of the said original web,

E. accumulating and stacking said pairs of sheets into a stack while maintaining at least the same cut ends of each pair as a reference for said stack.

2. The method as claimed in claim 1 in which the two patterns are disposed on the same face of the moving web.

3. The method as claimed in claim 1 in which the direction of movement of at least one of the half webs is changed after division to convert the moving half webs from side-by-side disposition to a disposition which will bring them into said face-to-back engagement.

4. The method as claimed in claim 2 in which said dividing is accomplished by slitting, and in which said directing is effected by diverting at least one of said half webs independently of the other to convert the side-by-side disposition of said half webs to dispositions which will bring them superposed into said face-to-back engagement, one of said half webs being laterally shifted relative the other.

5. The method as claimed in claim 4 in which both half webs are turned on different levels and in'which the half webs are brought into face-to-back engagement both moving in a directional path that is angular with respect to the path of both half webs prior to the diversion of either.

6. The method as claimed in claim 4 in which only one of said half webs is turned whereby the directional path of both half webs when in said face-to-ba ck engagement is not substantially different from the lateral location of the path of the unturned half web after dividing.

7. The method as claimed in claim 1 in which said web is perforated prior to dividing along the same respective edges of both patterns with the perforations lying in a line spaced from said one pattern equally along the length of said web and with the perforations equally spaced apart each perforation having a companion located at an identical point along the length of the web but laterally spaced from itself whereby there will be pairs of perforations along the length of the web, and the perforations having a repeat grouping that recurs at a rate capable of being synchronized with the said repeat locations at equal points along the length of the web, the perforations of each cut sheet also aligning with the perforations of its companion forming the pair of sheets so that when said pairs of sheets are cut at one of said points, the perforations of any one pair will be registrable with the perforations of all other pairs to enable alignment by spindling during stacking.

8. The method as claimed in claim 7 in which the perforating is done before imprinting.

9. The method as claimed in claim 7 in which the perforating is done after imprinting.

10. The method as claimed in claim 4 in which the said web is perforated prior to dividing along similar edges of the respective patterns, there being a line of individual perforations along each such similar edge, the perforations being identically equally spaced along the length of the web and located at identical points along the length so that each perforation has an identical perforation spaced laterally thereof to form therewith a pair, one of each pair of perforations being alongside of the respective patterns, the perforation pairs having a repeat grouping that recurs at a rate capable of being synchronized with the said repeat locations at equal points along the length of the web, so that when said pairs of sheets are cut at one of said points, the perforations of any one pair will be registrable with the perforations of all other pairs to enable alignment by spindling during stacking.

11. The method as claimed in claim 4 in which said slitting is effected by slitting along two lines, one slit line being spaced laterally a predetermined distance from one edge of the web and having one pattern between it and said edge and located between the two patterns, the other slit line being substantially the same predetermined distance from the one slit line and having the second pattern between it and the first slit line and being closely adjacent to the second edge of the web, whereby the cut sheets of each pair will be substantially the same width notwithstanding lateral drift of the web.

12. The method as claimed in claim 10 in which the line of perforations of one pattern is located adjacent one edge of said web between said one pattern and said one edge, and the line of perforations of the other pattern occurs between the said other pattern and the center of said web whereby when so slit, each half web will have one line of perforations along the similar edge thereof.

13. The method as claimed in claim 12 in which said slitting is effected by slitting along two lines, one slit being spaced laterally a predetermined distance from said one edge of said web whereby to have said one pattern and one line of perforations between it and said one edge and being located substantially at the center of the web between the two patterns, the other slit line being substantially the same predetermined distance from the one slit line and having the second pattern and second line of perforations between it and the first line and being closely adjacent the second edge of the web, whereby the cut sheets of each pair will be substantially the same width notwithstanding lateral drift of the web.

14. The method as claimed in claim 13 in which the said one edge and second slit line of each pair of sheets are used as lateral references in stacking said sheets.

15. The method as claimed in claim 14 in which said sheets are jogged while stacking.

16. The method as claimed in claim 15 in which said sheets are spindled into at least one perforation of each sheet at an end thereof during stacking and jogging.

17. The method of making honeycomb core structure in a stack suitable for further processing by at least expanding the same, which comprises:

A. imprinting parallel lines of adhesive on the face and transversely of an elongate substantially continuously moving web of flexible material suitable for making honeycomb core structure, said parallel lines being arranged in two independent patterns on respective lateral halves of the web with the lines of one pattern staggered relative to the lines of the other,

B. slitting the web up its center to divide the same into two half webs moving side by side,

C. turning the half webs relative to one another diverting at least one first in a plane diverging relative the other and then in a plane converging relative the other so as to bring the half webs into laterally aligned face to back engage ment with one another with the face of one engaging the back of the other,

D. cutting predetermined lengths of the engaged sheets simultaneously,

E. accumulating the sheets to form a stack of aligned sheets referenced from a cut end thereof.

18. The method as claimed in claim 17 in which the patterns are imprinted on the face of the web only and the back of the web is unprinted.

19. The method as claimed in claim 18 in which the adhesive is resinous and the web is temporarily dried prior to slitting but is capable of being heated to activate the adhesive to a permanently adhering condition after stacking.

20. The method as claimed in claim 19 in which the web is temporarily dried by heating and is thereafter cooled prior to slitting.

21. The method as claimed in claim 18 in which the web is perforated prior to slitting along a pair of lines of perforations, each line being spaced laterally of one another and having equal spacing along the length of the web, with the individual perforations of one line having identically laterally located perforations in the other line, each line being equally laterally spaced relative to one pattern and having a repeat grouping capable of being synchronized with the repeat of the patterns to enable the use of said perforations for registration during stacking.

22. The method as claimed in claim 17 in which the back of the web is imprinted with the identical patterns but each back pattern is staggered with respect to the pattern on its face half and with respect to its companion pattern on back half of the web, and in which a blank web is laminated to one of the face or back before slitting.

23. Apparatus for making honeycomb from flexible sheet material, comprising:

A. means for mounting a roll of raw sheet material and feeding and guiding the same in a substantially continuous movement through said apparatus,

B. a printing station for applying adhesive lines to said web and comprising a printing roll having axially extending printing lines in two axially spaced continuous patterns with the lines of said patterns staggered one relative to the other whereby to print two side by side patterns staggered on one surface of said web as it passes said printing station,

C. a drying station having the imprinted web passing through the same, and serving to dry temporarily the adhesive imprinted thereon,

D. a slitting station having means for slitting the web up its center to form two half webs, each with a pattern on one face thereof and being blank on the back thereof,

E. a turning station for angularly diverting at least one of said webs to change the side by side disposition of said half webs to a laterally aligned face to back disposition, said turning station including at least one pair of half web direction-changing turning bars and at least one of said half webs being directed to move divergingly from the other and thereafter turn to shift laterally and convergingly relative to the other,

F. means for laminating the two half webs in said face to back engagement with the imprinted face of one engaging the blank back of the other,

G. a sheeter receiving the laminated half webs from the laminating means and arranged to cut the same simultaneously in predetermined lengths and discharging same in pairs and,

H. means for accumulating the cut sheets for stacking.

24. The apparatus as claimed in claim 23 in which means are provided for adjusting the relationship of said patterns to maintain their original staggered relationship along their lengths after having been separated by slitting and prior to laminating.

25. The apparatus as claimed in claim 24 in which perforating means are provided for applying a line of perforations adjacent each pattern along the same edge thereof prior to slitting so that each half web has a line of perforations for aid in stacking.

26. The apparatus as claimed in claim 24 in which means are provided for drawing the two half webs prior to passage to said sheeter for maintaining tension therein at said sheeter.

27. The apparatus as claimed in claim 23 in which said accumulating means includes a bin slanted downwardly away from said sheeter and disposed to receive the sheet pairs discharged therefrom by gravity.

28. The apparatus as claimed in claim 27 in which the bin is laterally shiftable to enable quick replacement thereof by a second bin when said first bin has accumulated a desired amount of sheets.

29. The apparatus as claimed in claim 23 in which said slitting means comprise two knives, a first knife for cutting the web at the center and a second knife for trimming along one edge a predetennined distance from the first knife to enable establishment of lateral edge references for the resulting half webs.

30. The apparatus as claimed in claim 23 in which said turning bars are arranged at an angle to the movement of the half webs before turning, one being spaced from the other perpendicularly relative to the movement of the half webs before turning, each half web being directed to engage over one turning bar but at difierent levels, and both half webs thereafter moving in a direction angled relative to their direction of movement before turning.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3912573 *Feb 11, 1974Oct 14, 1975Bernard P KunzApparatus for producing core material for honeycomb panels
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US8142592Oct 1, 2009Mar 27, 2012Mylan Inc.Method for making a multilayer adhesive laminate
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Classifications
U.S. Classification156/197, 156/260, 156/512
International ClassificationB31D3/00, B31D3/02
Cooperative ClassificationB31D3/0276
European ClassificationB31D3/02C4