US2806413A

US2806413A - Creasing device

Info

Publication number: US2806413A
Application number: US404743A
Authority: US
Inventors: Raymond E Crooke
Original assignee: Sperry Rand Corp
Current assignee: Sperry Corp
Priority date: 1953-12-31
Filing date: 1953-12-31
Publication date: 1957-09-17
Anticipated expiration: 1974-09-17

Description

Sept. 17, 1957 Filed Dec. 31, 1953 mmilly/l /lll I R- E. CROOKE CREASING DEVICE 2 Sheets-Sheet 1 P 1957 R. E. CROOKE 2,806,413 CREASING DEVICE Filed Dec. 31, 1953 2 SheetsSheet 2 46' 50 /0 A 4 Q52 43 4 RA Y/m/vp wk:-

A TTOEWEY United States Patent CREASING DEVICE Raymond E. Crooke, Roslyn Estates, N. Y., assignor to Sperry Rand Corporation, a corporation of Delaware Application December 31, 1953, Serial No. 404,743

13 Claims. (Cl. 93-581) The present invention relates to the art of creasing comparatively stiff but pliable sheet material, such as cardboard, in preparation for folding along predetermined lines, in the manufacture of cartons, display stands and the like.

In the creasing of carboard sheet, one method of creasing is to form a depression or channel on the finished side of the sheet and a ridge on the inner side of the sheet with parallel scores flanking said ridge. Such a sheet can be creased by means of a pair of opposed relatively movable pressing members, one of which carries a creasing male die or rule adapted to bear against the finished side of the sheet, the other pressing member having a female die groove into which the sheet is adapted to be pressed by said male die. A device of this type forms a channel on the finished side of the sheet against which the male die bears and a ridge on the opposite side where the sheet is pressed into the die groove. If the grooved pressing member has square corners at the sides of the female die groove where said pressing member bears against the sheet, then the parallel scores formed on the sheet by these corners will not be sharp and clean-cut, so that the sheet may not follow well-defined hinge actions along said scores, especially when the sheet is folded rectangularly along said scores in forming a carton or other finished article from the creased sheet.

Where the creasing operation is performed with the male die rigid with the pressing member which carries said die and with the sheet stretched and clamped tautly between male dies in the formation of parallel panelling multiple creases, then such an operation presents difficulties, increasing (1) when creasing along the grain of the sheet, (2) with thicker sheets, (3) with dryer sheets, (4) as multiple parallel creasing lines come closer together, i. e., with narrow panels, (5) with rotary creasing as distinguished from flat bed creasing, (6) as the speed of operation increases, and (7) as the sheet density increases. The reasons for some of these difiiculties are as follows:

(1) When the score lines on one side are across the grain of the sheet, the surface fibres on this side of the sheet usually break along definite lines and these score lines are usually permanent. When the score lines are made along the grain of the sheet, impurities cause irregular lines and the scores tend to rebound. For these reasons, scoring and creasing are more difiicult along the grain of the board sheet.

(2) Thicker sheets have more fibres which go into the ridge, thereby presenting a stronger fulcrum resisting compression between the panels on opposite sides of said ridge, as the creased sheet is folded, and causing the sheet on the finished side to stretch and crack.

(3) A dryer sheet is less resilient, so that the finished side of the sheet cracks more easily.

(4) As multiple parallel creasing lines come closer together and the panels become correspondingly narrower, difliculties in creasing are encountered due to the fact that the sheet is stretched and held tautly between ice male creasing dies. Before creasing the sheet is flat across the area to be creased. In the formation of the ridge, as described, the sheet becomes arched across this area. The difference in length between these two crosswise areas is the draw. The material for this draw comes mainly from a movement of the sheet at either side of the crease towards the crease itself. In rotary creasing, if the longitudinal direction of the crease is at right angles to the direction of sheet travel, the sheet material for this draw comes from either the feed side or delivery side of the creasing rolls or both, so that the result is merely the use of more sheet material. If, however, the longitudinal direction of the crease is parallel to the sheet travel, and if there are multiple crease lines, then the extra sheet material for the draw comes from stretching the sheet. The tension resulting from this stretch increases as the panels become narrower, and the result is a tearing or breaking of the board sheet along the crease.

(5) With rotary creasing, as distinguished from flat bed creasing, the difficulties stated above increase, since with rotary creasing, the maximum deflection is almost instantaneous, affording thereby little time for draw adjustment in the sheet material, while with flat bed creasing, there is a finite time during which maximum deflection takes place.

(6) With increase in the speed of operation, the maximum deflection is more instantaneous, allowing less time for draw adjustment in sheet material.

(7) Increase in sheet density has substantially the same effect as increase in thickness of the sheet. described above under heading (2) and for the same reason.

Moreover, with the male die rigid with its supporting member, if this die is not exactly centered with respect to the opposed female die groove, one score line will be heavier than the other along a crease.

One object of the present invention is to provide a creasing device designed to apply, distribute and control the creasing forces on a board sheet in such a manner as to impress thereon, free from mutilation and defacement of the finished surface, a clean, distinct crease line having Well-defined hinge action for folding.

Another object of the invention is to provide a creasing device, which, because of the manner in which it applies, distributes and controls the creasing forces on a sheet, can be operated efiectively at comparatively high speed, to produce a clean, Well-defined crease line with a minimum of mutilation and defacement.

A further object is to provide as a new article of manufacture, a sheet of comparatively stiff but pliable sheet material creased and scored in a novel manner to permit smooth accurately conformed folding action, with a minimum of surface defacement and with such well-.defined hinge action as to permit clean rectangular folding along the crease lines.

In accordance with certain features of the present invention, the creasing device comprises a pair of opposed pressing members between which the sheet to be creased is placed or fed. One of these pressing members has a groove in which lies a male creasing die in the form of a slender rod or wire, projecting beyond. the surface of said member against which the sheet reposes during creasing operation, to imprint a shallow channel on the finished side of said sheet. The die rod is dimensioned to afford side clearances in this groove, and although seated firmly on the bottom of this groove, is free to move sideways therein as the rod and sheet are pressed relatively together.

The other pressing member has a groove opposite the male die rod to serve as a female die for the projecting part of this rod during creasing operations. The walls bounding the sides of this female die groove terminate peripherally in respective thin edges to serve as scoring blades, these edges being sharp enough to imprint definite furrows on the inner or unfinished side of the sheet, to serve as hinge orrscore lines, but not sharp enough to cut the surface or-fibers o'f'said sheet. 7

In operation, as the two pressing members move relatively towards "eachother to press the sheet 'there'between, the die rod on one of these pressing members moves against one side ofithe sheet, pressing the shee't "into the female die groove of the other pressing member, "while the edges of the score blades flanking this female die groove-clamp the sections of the sheet -on opposite sides of the die rod against the pressing member carrying the die 'rod. During this action, the sheet -is 'drawn and tension-ed and since the die rod 'is free to move sideways 'in its 'retaining grooveythe rod and the sheet will automatically adjust themselves relatively under this action, into position to equalize, centralize "and control the stresses on the sheet. As a result of this action, there *are formed a shallow channel on one side of the sheet where the die rod presses thesheet, a ridge on the opposite side of the sheet where said sheet is forced by said die rod into the female die groove, and two narrow paral- "lel hinge fur-rows on the latter side ofthe sheet flanking said ridge where the edges of the scoring blades bounding the sides of said female die groove are thrust into said sheet and serving as scores. Because of the selfequalizing and adjusting action between the die rod and the sheet described, the channel, ridge and scores are impressed upon the sheet with exactness, precision, regularity and uniformity, and compositely define a symmetri- *ca'l crease line which is clean and well-defined and which does not present any of the mutilations and surface defacements attending other known creasing operations. The sheet so creased, is adapted to be folded with the channel side outward. When so folded, the sheet will hinge neatly and cleanly about the two parallel "scores with evenness and regularity, causing the ridge on the inner side of the sheet between these scores to form a rib or head of uniform cross-section along the fold, while the crease line on the outer exposed side of the sheet is almost imperceptible. Surface ornamentation or printing on the exposed surface of the sheet will, there- "fore, not be disturbed or marred by this crease'line.

As another *featureof the present invention, the creasing device is designed to provide slacks between creasing stations during creasing operations, thereby affording the necessary sheet material for draw without stretching the sheet. In the case of a rotary creasing device, the pressing member carrying the female die groove has a series of these grooves spaced therealong for multiple creasing and annular recesses or hollows between adjacent creasing stations. The sheet may constitute a "continuous strip, which after creasing is cut transverse 'ly to form individual blanks and which, as it is fed lengthwise into position for creasing, is tensioned and pressed against the pressing member carrying "the female *die grooves. This causes the sheet to bulge transversely into the recesses between the creasing stations, thereby aflording in said sheet the "necessary slacks between adjacent creasing stations before the sheet is clamped at these stations by the creasing operation. By producing such slacks in the sheet, draw is provided, without stretching the sheet or with insignificant stretching, thereby preventing the finished surface of the sheet from cracking during creasing.

In the case of flat bed creasing, slacks .in the sheet between creasing stations may be created, by providing means to arch the sheet slightly, as the pressing members move relatively together, this sheet-arching means being yieldable, to ,permit the sheet to flatten outas the ridge-shaping operations along the creases require draw :material.

Due to the uniformity, accuracy and control inherent in the creasing operation described, this operation can be carried out a comparatively high speed without 4 any substantial impairments of the improved results described.

Various other objects, features and advantages of the present invention are apparent from the following description and from inspection of the accompanying drawings, in which:

Fig. l is a fragmentary view of a general assembly showing partly in end elevation and partly in section a rotary creasing device embodying the present invention;

Fig. 2 is a fragmentary view of the creasing device partly in end elevation and partly in section, taken on lines 2-2 of Fig. 4 but on an enlarged scale;

Fig. 3 is a detail section of the creasing device taken on lines 3-3 of Fig. 2',

Fig. 4 is a fragmentary side elevation of the creasing device;

Fig. 5 is 'a detail section of the creasing device taken on lines S -5 of Fig. 2 but showing said device on a larger scale;

"Fig. 6 is a detail enlarged section of the means for anchoring one section of the male die rod and for tensioning said rod if this is required;

Fig. 7 is a detail enlarged section of the means for holding another section of the male rod die radially inwardly from the general circumferential line of the groove retaining said die rod;

Fig. 8 is a detail section of a creasing :device of the fiat "bed 'type' embodying the present invention;

Fig. 9 is an inside face view of a part of the sheet, after it has been creased by -a device of the present invention;

Fig. '10 is an end view of the creased sheet, showing in dot-and-dash lines the sheet in fiat condition and showing in full lines the sheet folded in the process of forming the finished article, such as a carton.

Referring to Fig. 1 of fthe "drawings, the creasing device of the present invention comprises a pair of -'opposed sheet-creasing presses 10*and 11 serving as ereasin'g'die carriers between which the sheet A to be-creased 'is fed. Although these pressing members 10 and =11 are shown in the form of generally cylindrical rolls' for continuous rotary creasing operation in Figs. 1- 5, the invention also applies to a hat bed creasing operation in 'which both pressing members are flat and the creasing is accomplished by 'a reciprocating motion of one zpress'in'g member towards "and away from the other.

The axes of the two rolls 1-0 and 11 may be adjusted relatively towards or away from each other, to accommodate sheets of different thicknesses. For that purpose, one of the "roll shafts may be supported on bearings movable towards or away from the axis of the bearings for the other roll shaft, in the manner wellknown 'in the creasing art, to effect the necessary adjustments between "the rolls.

The sheet A to be creased is shown as constituting 'a continuous strip "made of comparatively stiff but pliable material, such as cardboard or pasteboard, from which such articles as cartons, display stands and the like may be manufactured. 'This sheet is shown in Fig. I pulled from a reel 12, trained over the pressing roll '10, fed through the nip or'bi'te'betwee'n the two pressing rolls 1'9 and 11 for creasing and passed to a delivery station for further processing.

The continuous s'heetJA is impressed by the device of the present invention with a crease line or with a series of crease lines according to 'thenature of the articles to be made therefrom, and after creasing, may be cut transversely .to form individual blanksfrom w hich the final articles, such as cartons, may he .made. The length of each blank maybe .sorelated to.thegperipheralilength of the roll .11, as to cause a length of section corresponding to a number of :blanks to passthrough the .field rof creasing operation (snip or bite) of the creasing device for every revolution of said roll. In the specific form of the in vention shown, the length of sheet section passing through the field of creasing operation of the device for every revolution of the roll 11 corresponds to two successive blanks, with intervening parts designated for carton closure flaps or the like. The creasing device is, therefore, designed to form two creasing patterns on the sheet for every revolution of the lower roll 11, as will be more fully described.

The lower roll 11 is designed to carry the male part of a creasing die. To receive this male die part, the roll 11 has a peripheral groove 13, which is shown of rectangular cross-section with a cylindrical base 14 for seating a male die 15 in the form of a slender rod and more specific-ally in the form or" a flexible metal wire or cable. This wire 15 is preferably of round cross-section and is of a diameter greater than the depth of the groove 13, to cause the outer section of this wire to project radially outwardly beyond the outer cylindrical surface 16 of the roll 11 on the sides of said groove, when the wire is seated on the base 14 of said groove, but smaller than the width of said groove, to provide clearances 17 between the sides of said wire and the corresponding side walls of said groove.

The upper roll 11 carrying the female part of the creasing die has a peripheral groove 18 opposite to and approximately centered with respect to the wire-retaining groove 13 of the lower roll 11 to receive the projecting part of the male die wire 15 at the bite region of the rolls and 11. This female die groove 18 is wider than the wire-retaining groove 13 and has side wall members 20 projecting axially outwardly beyond the sides of the groove 13 and tapering in cross-section to form respective V- blades with scoring edges 21 located and arranged to press the sheet A against the cylindrical surface 16 of the roll 11 in the nip or bite of the

rolls

10 and 11. Those sections of the cylinder surface 16 flanking the wireretaining groove 13 and extending in opposite directions away from said groove, thereby serve as platens for the scoring blades 20 to receive the pinching pressure therefrom.

In the specific form of the invention shown, the female die groove 18 is rectangular in cross-Section, so that the inner confronting faces 22 of the scoring blades 20 are parallel and in planes at right angles to the axis of the roll it while the outer faces 23 of these scoring blades 20 slope towards the corresponding inner faces for bevelling. However, as far as certain aspects of the invention are concerned, the female die groove 18 may be of any other cross-section, and the two faces of each scoring blade may slant one towards the other, in any other V- pattcrn, to define the scoring edges 21. edges 21 are sharp enough to pinch into the sheet A and form furrows or score lines therein, without actually cutting into the surface or fibers of the sheet.

The die wire is retained in the groove 13 against its base 14 and may be tensioned to assure its proper stable seating on said base against undulating movement thereon during creasing operations, while permitting said wire to slide transversely across said base in response to the side pressure thereon of the sheet A being creased. For that purpose, the wire'15 is shown of a single length passing around the roll 11 in the groove 13 and having its ends fastened in a pair of anchoring and tensioning devices 25 located in a recess 26 in the roll 11. Each of these anchoring and tensioning devices 25 may be of any suitable type, and is shown comprising a stud 27 threaded into the roll 11 and having a diametrical slot 28 at its outer end to receive a suitable turning tool such as a screw driver. The end of the wire 15 passes through a di-ametrical hole 3% in the stud 27 and is partially wound around said stud. A collar 31 with a loose slide fit on the stud 27 between the wound end of the wire 15 and the roll 11, serves as a shoulder for said wire end, and a lock nut 32 on the stud 27 clamps the end of the wire 15 against said collar. A cotter pin 33 prevents complete detachment of the lock nut 32 from the stud 27.

These scoring r .When it is desired to adjust the tension on the wire 15, the lock nut 32 is backed away from the clamped end of the wire, and the stud 27 is turned in the direction to wind this wire end on the stud or unwind it from said stud, according to the nature of adjustment desired. After the necessary adjustment in the wire tension has been made, the nut 32 is turned into locking position against the wound end of the wire 15.

Two tensioning devices 25 may be provided to facilitate adjustment and to assure even distribution of the tensioning forces along the wire 15. These two anchoring and tensioning devices 25 are set inwardly in the roll recess 26 to define an inactive section between the ends of the wire, where no creasing in the sheet A takes place. The uncreased section of the sheet A resulting from this inactive section of the roll 11 may constitute the area between the bl-ank-defining parts of the sheet, where the sheet is to be cut and where perhaps the carton closure ilaps for the blanks are to be formed.

Since the roll 11 is designed to form on the sheet A for every revolution of the roll, two separate creasing patterns for two separate blanks, the section 35 of the wire 15 intermediate its ends is set radially inwardly from the circumferential line of the wire-retaining groove 13, by means of two holding devices 36 in a recess 37 in the roll 11. Each of these wire-holding devices 36 may be of any suitable type and is shown comprising a stud 38 threaded into the roll 11 and having a diametrical slot 4% in its outer end and a collar 41 integral with or otherwise made rigid with said stud for shouldering said stud in fixed locked position. This stud 38 has a diametrical hole 42 through which the wire 15 passes.

The section of the Wire 15 where it is set inwardly in the recess 37 is inactive, so that the roll 11 has two diametrically opposite die-free sections forming on the sheet A, two spaced creasing patterns for every revolution of the roll 11. The scoring blades 20 are also interrupted to correspond to the interruption in the continuity of the wire 15. The two creasing patterns formed by this construction on the sheet A are shown identical, with the two sets of creases in respective alignment, but could be difierent and could be offset, simply by providing two wires axially offset along the roll 11 and by providing two female die grooves correspondingly offset on the roll 10.

If desired, instead of employing tensioning devices for adjustably maintaining the die wire 15 seated on the base of the groove 13 against undulating movement, the trailing end of the wire 15 may be anchored with a lost-motion connection, so that any slight slack in the wire causing slight wave movement is progressively ironed out towards said connection and released thereby, while the creasing roll 11 rotates.

In the case where the sheet A is to be creased with. a series of lines, as for example, to form a carton, the lower roll 11 carries a series of male die parts, similar to the parts described, and the upper roll 10 carries a corresponding number of female die parts and corresponding pairs of scoring blades, as shown in Figs. 3 and 5. The

grooves

13 and 18 and the scoring blades 20 in these

rolls

10 and 11 may be machined out of a solid metal block, or the

rolls

10 and 11 may be compositely formed of discs, axially arranged face to face and secured together with bolts extending therethrough to define the

different grooves

13 and 18 and the scoring blades 20. Where the roll 11 is of unitary construction, this roll may be machined or cast to provide the recesses 26 and 37 (Fig. 2) for the

wireholding devices

25 and 36. Where this roll 11 is made up compositely of discs arranged axially side by side, the appropriate discs are provided with cut-outs to define the

recesses

26 and 37.

The ridges formed on the sheet require more sheet material than is available along the crease lines prior to creasing to provide for the draw. Where multiple crease lines are to be formed on the sheet simultaneously, unless some means are provided for the purpose demass or. recesses 45 into which the, sheet A intension in the tions. between creasing stations before the creases are made at the. nip point affords sufficient slacks to form the. ridges without materially stretching the sheet or otherwise mutilating it.

In the case of a flat bed creasing device, the means for providing the necessary slacks to afford sheet material for the ridges. without substantial stretching, are shown inv Fig. 8. In this form, the sheet-slacking means comprise props 46, each disposed centrally between adjoining creasing stations and normally extending beyond the sheetsupporting surface of a lower flat creasing bed 11a, which carries said props and which cooperates with an upper pressing member a. These props 46 are yieldable to permit the sheet A to flatten out, as the members 10a and 11a come together and as the crease lines being formed require material necessary to shape the ridges along said crease linesv without stretching. To that end, these props 46 are shown of flexible resilient material, such as soft rubber, although they may be of rigid material and spring-pressed for yieldable action. In operation, the props 46 arch the sheet A supported on the flat creasing bed 11a slightly, as the two pressing members 10a and 11a move relatively towards each other, to produce slacks in the panel sections of the sheet between the areas of the sheet to be creased. As the pressing members 10a and 11a come together, these slacks are taken up by the ridges being formed along the crease lines, causing the props 46 to be depressed and distorted into clearance spaces 47 provided around the props, so that the sheet is permitted to flatten out.

Although the arrangement of Fig. 8 is described as being applicable to a flat bed creasing. device, it is applicable. to. a rotary creasing device such as that shown. in Figs. 1-5, in cases where the sheet during feed around the upper roll .10 is not tensioned sufliciently to bulge the sheet into. the recessesor hollows 45.

Also, the props. 46 may beiprovided in the upper'presslngrnember carrying the female die grooves instead of in thelower pressing member, as long as the lower pressing member has hollows or recesses into whichthe panelsections of. the. sheet between the areas to be creased may be arched;

In the operation of the creasing device shown in Figs. l-5.,.the.. sheetis fed. continuously into the; field of action of." the. creasing device, withits side a, which. carries: the printing. and/ or. decoratiom. if any, and which will even: tuallybecome. the outer exposed side of the. final article;

facing the rolll11. As the sheet'is fed as described,.each

die. wire 15 on the lower roll 11, in its rotary course, pushes up progressively against the under side a of. the sheet and forces said sheet progressively into the corresponding female die groove 18 in the upper roll 10. At the same time, the scoring blades 20 on the upper roll 10 move rotatively and progressively towards position to press the sheet against the cylindrical surface 16 of the lower roll 11. During these actions, just before a transverse section of the sheet reaches the bite between the two rolls 10. and 11, this transverse sheet section bulges slightly into' the recess in the upper roll 10, asshown in Fig. 3. If diewireslS areinot centralized with respect t'o'the corresponding female diegrooveslS, asthe'se'wires move into contact with thissheetsection atis'pa'ce'd' points thereac'ro'ss, the pressures" between these wires and" the sheet cause the wires to slide transversely in their. respective, retaining .grooves v13, a. condition of equilibrium isLreached-justbefore saidssheet.section reaches a point where the scoring blades 20 clamp said sheet section against the cylindrical. surface I6 of the liiwef roll. and have begun to pinch into said sheet section without-cm; ting it. As the movement of this sheet sectioncontinues towards the bite between the

rolls

10 and 11, the scoring blades 20 will continue to press deeper into this sheet section, so that by the time this sheet section reaches the nip or bite of the

rolls

10 and 11, shown in Fig. 5, shallow channels 48 free from sharp corners will be formed on the underside a of the sheet section, where the die wires 15on the lower roll 11 have been bearing against said sheet section. At the same time, ridges 50 will be formed on the opposite upper side of the sheet section where this sheet section has been forced into the female die grooves 18 in the upper roll 10 and a pair of V-shaped furrows 51 will be scored in the upper side of this sheet section flanking each of saidridges, where a corresponding pair of scoring blades 20 have been pinching into said sheet section.

As a result of the progressive self-adjusting wire actions and the sheet-shaping actions described, there is continuously formed on the sheet A, a series of crease lines 52,- each having well-defined, uniform components, consisting of. a channel 48, a ridge 50 and a pair of definite equal flanking scores 51 of substantial depth. The side a of the sheet, which bears the channel 48 with its cross-section of unbroken streamline contour and which will eventually be the exposed side of the sheet in the final article, will be free from wrinkles and defacement and will present a smooth surface on which the creasing is almost imperceptible. The other side of the sheet will have V-shaped score furrows 51 on opposite sides of each ridge 5%, defining lines about which the sheet may be folded with Well-defined hinge action toformthe final folded article. As the sheet is so folded from its flat condition shown in Fig. 9 and in dot-and dash lines in Fig. 10 to the angular condition it will assume in the final folded article, as for example, a carton, shown in full lines in Fig. 10, the ridge 50 will be compressed sideways and shaped into a bead or rib of somewhat. rounded cross-section, thereby yieldably resisting folding. action with resiliency, and afiording re inforcement for the crease line in the folded sheet. At the same: time, the folding of the sheet stretches out the channel 48 on the outer side a of the sheet, so that this channel will be smoothed out and not noticeable inthe final folded article. Any printing and/0r decoration. on the outer side: a of the folded sheet will therefore not be marred or mutilated.

The constructions and operations described. serve not only to form a neat, clean crease line, with minimum of defacement and mutilation of the sheet, but due to. the nature of these operations permit high speed operations without substantialirnpairment of these advantages.

While-the invention has beendescribed with particular reference to a specific embodiment, it is to be under.- stood that it is'not to be limited thereto but is to be construed broadlyv and restricted solely by the scope of the appended claims.

What isclaimed is:

1. A sheet-creasing device comprising a pair of op.- posed pressing members between which the sheet to be creased is adapted to be positioned, said members being mounted for relative movement towards andaway from each other for creasing operations, a wire seated on a surface of. one of said pressing members adapted to bear against one side of the sheet positioned between said members and slidable transversely across said surface forself-adjustment in response to the pressure action of the sheet, the other pressingmember having a female diegroove into. which the sheet is adapted to be pressed by saidwire during. creasing operation, to form aridge on the opposite side of the sheet, and means for form ing score-lines along said ridge on opposite sides thereof.

2. A sheet-creasing device comprisingapair of op; posed pressing members between which the sheet to be creased is adapted to be positioned, said members being mounted for relative movement towards and away from each other for creasing operations, a wire seated on a surface of one of said pressing members and adapted to bear against one side of the sheet positioned between said members, said wire being slidable transversely across said surface for self-adjustment in response to the pressure action thereon of the sheet being creased, means for adjusting the tension on said wire, the other pressing member having a groove into which the sheet is adapted to be pressed by said wire during creasing operation; to form a channel on one side of the sheet and a ridge on the other side, and a pair of scoring blades on the latter pressing member flanking said groove, to form on the sheet on opposite sides of said ridge a pair of score lines about which the sheet may be hinged for folding.

3. A sheet-creasing device comprising a pair of opposed creasing members between which the sheet to be creased is adapted to be positioned, said members being mounted for relative movement towards and away from each other for creasing operations, one of said pressing members having a groove facing the other pressing member, a wire retained in and extending along said groove, said wire being seated on the base of said groove and having a diameter smaller than the width of the groove to provide clearances between said wire and the sides of said groove, but larger than the height of the groove to cause said wire to project beyond the surface of the pressing member having said groove, said wire being adapted to bear against one side of the sheet between said members, the other pressing member having a groove into which the-sheet is adapted to be pressed by said wire during creasing operations to form a ridge on the opposite side of said sheet, said wire during said bearing action being adapted to slide transversely in its retaining groove in response to any unequal transverse pressure action thereon of the sheet for self-adjustment, and means for forming in the sheet on opposite sides of said ridge a pair of score lines, about which the sheet may be bent for folding.

4. A sheet-creasing device comprising a pair of opposed rolls between which the sheet to be creased is adapted to be fed, one of said rolls having a circumferentially extending peripheral groove and a cylindrical surface on opposite sides of said groove, a wire retained in and extending along said groove and seated on the base thereof for rotation with the latter roll, said wire being of a diameter smaller than the width of said groove to provide clearance for sidewise self-adjusting movement of the wire in said groove, but larger than the depth of said groove to cause said wire to project radially outwardly beyond said cylindrical surface and to bear thereby against one side of the sheet, the other roll having a circumferentially extending peripheral groove opposite said wire-retaining groove and into which the sheet is adapted to be pressed by said wire to form a ridge on the opposite side of the sheet, and a pair of rotary scoring blades on the latter roll flanking the groove carried by the latter roll and having scoring edges extending axially outwardly beyond the sides of the wire-retaining groove, to pinch the sheet against said cylindrical surface and to form thereby on the sheet on opposite sides of said ridge a pair of score lines about which the sheet may be folded.

5. A sheet-creasing device as defined in claim 4, comprising means for adjusting the tension on said wire.

6. A sheet-creasing device as defined in claim 4, said scoring blades having V-shaped peripheries terminating in edges sharp enough to pinch into the sheet to produce score lines in the form of furrows of V-shaped crosssection, but not sharp enough to cut into the sheet.

7. A sheet-creasing device comprising a pair of opposed substantially flat pressing members movable relatively towards and away from each other for creasing a sheet therebetween, one of said pressing members having a straight groove, and substantially flat surfaces on opposite side of said groove, a wire retained in and extending along said groove and seated on the base thereof, said wire being of a diameter smaller than the width of said groove to provide clearance for sidewise self-adjusting movement of the wire in said groove, but larger than the depth of said groove to cause said wire to project outwardly beyond said surfaces and to bear thereby against one side of sheet, the other pressing member having a groove opposite said wire into which the sheet is adapted to be pressed by said wire to form a ridge on the opposite side of the sheet, and a pair of scoring blades on the latter pressing member flanking the groove carried by the latter pressing member and having scoring edges extending axially outwardly beyond the sides of the wire-retaining groove, to pinch the sheet against said surfaces and to form thereby on the sheet on opposite sides of said ridge a pair of score lines about which the sheet may be folded.

8. A sheet-creasing device comprising a pair of opposed rolls defining therebetween a bite or nip into which the sheet to be creased is adapted to be fed, a series of male dies extending circumferentially around one of said rolls and spaced therealong in position to bear against one side of the sheet, said dies being carried by the latter roll for rotation therewith, the other roll having a series of circumferentially extending peripheral female die grooves opposite said male dies respectively and into which the sheet is adapted to be pressed by said male dies during creasing operation, to form a series of ridges on the opposite side of said sheet, and means for forming on the sheet on the opposite sides of each ridge a pair of score lines about which the sheet may be folded, one of said rolls having annular recesses between adjoining creasing elements thereon, the sheet when feeding into said bite being wrapped partially around the latter roll and being tensioned, whereby the sheet bulges slightly in said recesses before reaching said bite.

9. A sheet-creasing device comprising a pair of opposed pressing members relatively movable towards and away from each other for creasing a sheet therebetween, one of said pressing members having parallel grooves separated by sections presenting sheet-supporting surfaces, wires extending in and along said grooves respectively for retention therein and seated on the bases of said grooves, each of said wires having a diameter smaller than the width of its retaining groove to afford clearance permitting sidewise self-adjusting movement of said wires in their retaining grooves, but larger than the height of its retaining groove to cause said wires when seated on the bases of their retaining grooves to project radially outwardly beyond said surfaces, and to bear thereby against one side of the sheet, as the pressing members come together, the other pressing member having a ser'es of grooves opposite said wires respectively and into which the sheet is adapted to be pressed by said wires during creasing operation, to form a series of ridges on the opposite side of the sheet, a pair of scoring blades on the latter pressing member flanking each of the latter grooves and having its edges extending axially outwardly beyond the sides of the corresponding wire-retaining groove to press the sheet against said surfaces and to form on said sheet on the opposite sides of each ridge a pair of score lines, said scoring blades having bevelled sides adjacent to said edges, whereby the score lines formed constitute furrows of V-shaped cross-section, one of said pressing members having recesses between adjoining creasing elements thereon, and means for arching said sheet into said recesses just prior to the instant of maximum creasing deflection to provide slacks in said sheet for draw in the formation of the crease line ridges.

10. A sheet-creasing device comprising a pair of opposed pressing members relatively movable towards and away from each other and having creasing stations for producing on a sheet between said pressing members a "sheet, one "of said pressing members having recesses between adjoining creasing stations thereon, and props carried by the pressing member other than the one having said recesses adapted topress said sheet at the panel section's between creasing stations into said recesses, to arch said 'sheet'into said recesses prior to the instant of creasing deflectionto provide slacks in said sheet for draw in the formationof the crease line ridges, said props being yieldable to permit said sheet at the arched sections to 's'traig'htenout as dr aw takes place.

11. A sheet-creasing "device as described in claim 10, 'vvhereinsaid-device is of the flatbed type.

'12. A sheet-creasing device comprising a pair of opposed pressing members between which the sheet to be creased is adapted to be positioned, said members being mounted for relative movement towards and away from each other for creasing operations, a. plurality of creasing means for producing a corresponding plurality of creasing 'lines on the sheet, each of said creasing means comprising a slender rod-like creasing male die carried 'by one of said pressing members and adapted to bear against one side of the sheet positioned between said members, the other pressing member having a corresponding female die groove into which the sheet is adapted to be pressed by said male die during creasing operations to form a ridge on the opposite side of the sheet, said die groove having a width greater than that of the male die and having a depth and configuration in relation to the depth and configuration of the male die to cause said ridge to extend into said die groove with freedom between "the outer surface of said ridge and the opposed wall of 12 the said die 'roo'v'e in the region ef the bite or said press- 411g members where the sheet is fiilly creased, and a pair of -scor'ing blades on the pressing member carrying "the female die groove flanking said female die groove and having respective V-shaped cross-sections terminating in edges sharp enough to pinch and indent the sheet biit 'n0t'sharp e'nough to'cut into the sheet, the pressing member carrying the male die presenting a surface having sections which fifank and extend in opposite directions away from said male die and which are located opposite said edges to receive the pinching pressure from said scoring blades respectively as said pressing mern'bers' come "together, said s'cor'ing blades being adapted to impress furrows of corresponding V-shapied cross-section in the sheet, and means for arching the sheet between the scoring blade of one creasing means and the adjoining scoring blade of the next creasing means to provide slack in the sheet for draw in the formation of'the corresponding creaseline ridges, said arching means including a recess extending transversely from one or the last-two mentioned 'blades to the other blade and extending longitudinally across the region-of'th'e bite of said pressing members.

13. A sheet creasing device as described in claim 1-2, wherein said pressinginembers are in the form of rot'a'table rolls.

References Cited in the file of this patent UNITED STATES PATENTS 1,090,139 Wyman "a Aug. 8, 1911 1,302,831 Naugler May 6, 1919 1,941,484 Nasmith Ian. '2, 1934 2,612,305 Klas'ing et a1. 'Sept. 30, 1952