US3199861A

US3199861A - Apparatus for folding web material

Info

Publication number: US3199861A
Application number: US101757A
Authority: US
Inventors: Charles W Presnell; Walter A Schuh
Original assignee: Scott Paper Co
Current assignee: Kimberly Clark Tissue Co
Priority date: 1961-04-10
Filing date: 1961-04-10
Publication date: 1965-08-10
Anticipated expiration: 1982-08-10

Description

Aug. 10, 1965 c. w. PRESNELL ETAL 3, ,8

APPARATUS FOR FOLDING WEB MATERIAL 5 Sheets-Sheet 1 Filed April 10, 1961 INVENTORS. CHARLES W. PRESNELL WALTER A. SCHUH BY ATTOZNEY Aug. 10, 1965 c. w. PRESNELL ETAL 3,199,861 APPARATUS FOR FOLDING WEB MATERIAL Filed April 10, 1961 5 Sheets-Sheet 2 INVENTORS.

CHARLES w. PRESNELL Tmve' WALTER A. SCHUH ATTORNEY c. w. PRESNELL ETAL 3,199,861

APPARATUS FOR FOLDING WEB MATERIAL Aug. 10, 1965 5 Sheets-Sheet 3 Filed April 10. 1961 INVENTORS. CHARLES W. PRESNELL WALTER A. SCHUH ATTORNEY Aug. 10, 1965 c. w. PRESNELL ETAL 3,199,861

APPARATUS FOR FOLDING WEB MATERIAL 5 Sheets-Sheet 4 Filed April 10, 1961 INVENTORS.

CHARLES W. PRESNELL WALTER A. SCHUH ATTORNEY Aug. 10, 1965 c. w. PRESNELL ETAL 3,199,861 APPARATUS FOR FOLDING WEB MATERIAL Filed April 10, 1961 5 Sheets-Sheet 5 I81 78 i9 X 73 INVENTORS. CHARLES W. PRESNELL WALTER A. SCHUH *3 By 5/ F7 24 5551111111 M ATTORNEY United States Patent 3,199,361 APPARATUS FUR FULIDING WEE MATERIAL Charles W. Presnell, Media, and Waiter A. Schnh, Lansdowne, Pa, assignors to Scott Paper Company, Philadeiphia, Pa., a corporation of Pennsylvania Filed Apr. 10, 1961, Ser. No. 101,757 8 Claims. (Ci. 279-40) This invention relates to improved apparatus for folding webs of flexible material and more particularly for producing stacks of interfolded Webs of such material.

It is a principal object of this invention to produce in an economical manner and at a high rate of production stacks of interfolded webs, particularly webs of fragile, facial tissue and the like.

This invention is related to and constitutes improvements for the general type of web folding apparatus disclosed in Reissue Patent No. 21,785 to P. Burke et al. In the machine of the aforementioned patent, a continuous stack of folded tissure paper is formed on a moving conveyor by successively laying onto a moving conveyor webs of material which are folded as they are drawn from a plurality of parent rolls carried in a multiple spindle backstand. The moving stack of folded webs is severed at appropriate intervals to produce conveniently sized, individual stacks of folded sheets. The principal advantage of this machine over prior machines has been its ability to produce stacks of folded web material at high production rates.

Many present day brands of facial tissues, paper towels, and the like are packaged with portions of adjacent sheets interleaved, or interfolded, in such a manner that with drawal of the top-most or outer-most sheet causes a portion of the next sheet to be drawn through the delivery opening of the package Where it is readily accessible to the user. Naturally, attempts have been made to produce such interfolded products on a continuous basis, i.e., in the general manner of the machine described in the aforementioned Burke patent. To our knowledge however, such attempts have not been entirely successful in producing either a machine or a method which is both economical and reliable. This is particularly true with respect to methods and machines for interfolding webs of facial tissue which, because of their extremely fragile nature, are difficult to handle and fold without wrinkling or tearing. Prior attempts to produce machinery for interfolding facial tissue webs have resulted in large and complicated machines which are costly, and diflicult and expensive to maintain and operate.

A principal feature of this invention is that a multipleroll machine for producing interfolded webs and embodying the invention occupies substantially no more floor space than a similar machine adapted for producing noninterfolded stacks of webs, although the folding operations performed on the latter machine are considerably less extensive than those required for producing interfolded stacks.

In certain prior machines in which a stack of folded webs is formed on a moving conveyor it has been the practice to provide a folding or interfolding device at the conveyor for each web that is to be added to, or connected to, the moving stack. Inasmuch as it is seldom economical to market stacks of fewer than 100 sheets, such machines have had 100 or more folding, or joining, stations along their conveyors with the result that the machines occupied an undesirable amount of floor space. In accordance with the present invention, certain pairs or sets of webs fed to the stack conveyor are preliminarily folded and interfolded away from the immediate vicinity of the stack conveyor. A reduced number of final interfold stations are thus required at the conveyor and these are of improved design capable of handling pairs or sets of preliminarily interfolded webs. In this manner, the overall length of j hfihi Patented Aug. 10, 1965 "ice the conveyor is held to a minimum, the length of the ma chine is minimized and, consequently, the amount of floor space occupied by the machine is held to a minimum.

Another problem encountered in operating prior machines for producing interfolded webs has to do with threading webs from newly placed parent rolls through the several folding devices which are required to impart the desired folds to the Webs. Such threading operations are particularly complicated in a machine for producing interfolded webs because not all of the webs are folded to the same hand. In other words, certain webs must possess right-hand folds and adjacent webs must possess left-hand folds in order for the webs to interleave in proper relationship in the finished stack.

Another important object of this invention, therefore, is the simplification of the web threading operation in multi-web folding equipment. This objective is accomplished by a novel arrangement and design for the several folding devices employed in the machine, whereby such devices are accessibly located and conveniently presented to the tender of the machine for threading purposes.

A further object of the invention is the interfolding of multiple webs of fragile facial tissue without wrinkling, tearing, or breaking any of the webs.

A still further object of the invention is the provision of improved folding devices capable of alternatively folding one or both edge portions of webs conveyed thereover to render the machine capable of producing variously folded webs and of producing interfolded and non-interfolded stacks of webs.

These and other objects, advantages, and features of the invention will be apparent from the following detailed description of the invention in which reference is made to a preferred embodiment thereof illustrated in the accompanying drawings, wherein:

FIGURE 1 is a front elevational view of apparatus for folding and assembling webs of flexible material in accordance with this invention;

FIGURE 2 is a perspective view of a plurality of webs as they appear in moving through the apparatus of FIG- URE 1;

FIGURE 3 is a diagrammatic view illustrating certain folding and inter-folding steps performed by the apparatus of FIGURE 1;

FIGURE 4 is an enlarged, side elevational view of a folding device employed in the apparatus of FIGURE 1 and which is capable of folding one or both longitudinal edges of a moving web;

FIGURE 5 is an elevational view of the web face of the folding device shown in FIGURE 4;

FIGURE 6 is a view similar to FIGURE 5 but on a reduced scale and showing a folding device of opposite hand;

FIGURE 7 is a rear elevational vieW of the folding device of FIGURE 4, but showing the components thereof in different positions by which another type of web fold is produced;

FIGURE 8 is a fragmentary, three-quarter rear perspective view of the folding device of FIGURE 4 illustrating the manner in which a web of material passes thereover;

FIGURE 9 is a transverse sectional view of the folded web leaving the folding device of FIGURE 8;

FIGURE 10 is a view similar to FIGURE 8, but showing the components of the folding device in position to produce a C-fold in the Web passing thereover;

FIGURE 11 is a transverse sectional view through the web leaving the folding device of FIGURE 10;

FIGURE 12 is a front elevational view of another folding device employed in the apparatus of FIGURE 1;

FIGURE 13 is an elevational view of the web face of the folding device of FIGURE 12;

. lurality of parent rolls 32 of web material. 31 includes a plurality of arbors, or spindles, 33, preferover its folding devices and 39.

ings.

FIGURES 14 through 16 are views illustrating the manner in which the folding device of FIGURE 12 assembles two moving webs of material, FIGURE being a sectional view taken as indicated by line I5-15 in FIGURE 14;

FIGURE 17 is a plan view of an interfolding device employed in the aparatus of FIGURE 1;

FIGURE 18 is a front elevational view of the interfolding device of FIGURE 17;

FIGURE 19 is a vertical section through the interfolding device taken as indicated by line 19-19 in FIG- URE 17;

FIGURE 20 is a fragmentary perspective view from above, illustrating the manner in which Web is folded in passing through the folding device of FIGURES 17-19.

FIGURE 21 is a perspective view from below of the web shown in FIGURE 20;

FIGURE 22 is a view similar to FIGURE 20, but illustrating the manner in which the interfolding device assembles a pair of webs to a moving stack of interfolded webs;

FIGURE 23 is a transverse sectional view taken generally as indicated by line 2323 of FIGURE 22;

FIGURE 24 is a diagrammatical illustration of the -web formation shown in FIGURE 23;

FIGURE 25 is an enlarged elevational view of a conveyor supporting device employed in the apparatus of FIGURE 1.

Referring particularly to FIGURE 1, the apparatus there illustrated constitutes a portion only of a machine for producing stacks of interfolded webs of material, such as webs of facial tissue, paper toweling, etc. Although it is the general practice to market facial tissues or the like in packages of 100 or more sheets and machines for producing such packages normally handle a plurality of webs equal in number to the number of sheets desired, or more, the principles of the present invention can be readily understood from an examination of but a portion of such a machine. The appartus shown in FIG- URE 1 comprises a stand 31, sometimes referred to as a backstand, which functions to provide support for a The stand stand 31. The four webs from each stack of parent rolls 52 meet at another guide roller 37 before passing into .a lower, folding and assembling region of the machine. Positioned within this region of the machine are a plurality of folding devices of two types, designated and 39 respectively. Folding devices 38 and 3% have individual webs 34 guided thereto by further guide rollers 48'.

Each web 34 receives a preliminary fold in passing For convenience in identifying this folding operation and the fold produced thereby, reference numeral I is employed in the draw- The precise nature of fold I is described herein after.

Preceding downwardly from

folding devices

33 and 39 the webs are conveyed over suitable guide rollers 41, are directed into pairs and directed to a further set of folding devices, each of which is identified generally by numeral 42. .A preliminary interfold, identified as fold II, is

.performed on each pair of webs moving over folding device 42. The pie-interfolded pairs of webs thereafter pass through pairs of press rollers into a set of final interfold devices 44, which are serially arranged along a moving conveyor 46. One or both rollers of each pair of rollers 43 may be driven for the purpose of drawing webs 34 over and through folding devices 38, 35, and 22.

Each pair of webs passing through a final interfolding device 44- has a fold, identified as III, performed thereon which assembles that pair of webs in interfolded relationship with a moving stack of interfolded webs 47 carried on conveyor 46. Conveyor 46 is driven by any suitable source of motive power, such as an electric motor, and functions to convey the assembled stack of interfolded webs to a severing device (not shown) by which individual, package-sized stacks are obtained. Conveyor 46 also functions to draw the Webs through folding devices Movement of the conveyor 46 may be either continuous or intermittent, as desired.

The above constitutes a brief description of the major components of the apparatus embodying the invention. The method of folding and interfolding webs contemplated by the invention and the steps involved in the method can be best ascertained by reference to FIGURES Zand 3 of the drawing, which diagrammatically display the folding operations performed on the webs passing through the apparatus. Continuous webs progressively being subjected to operations to produce folds I, II, and III are illustrated in FIGURE 2. FIGURE 3 contains diagrammatic illustrations of cross sections of the web folds in four webs, i.e., the number of webs fed from a single stack of four parent rolls 32 (see FIG. 1). For convenience, the four webs are identified as A, B, C, and D.

The folding method includes imparting fold I to each of webs A, B, C, and D by which one longitudinal edge portion of each web is folded back onto a contiguous portion of the web. This fold usually is described as a J-fold because when represented diagrammatically, as

shown in FIGURE 3, the folded web resembles the letter I. It will be noted that alternate ones of the webs are oppositely folded. A and C, for example, which pass over folding devices 38, have imparted thereto right-hand folds While webs B and D, which pass over folding devices 39, have left-hand folds imparted thereto. Oppositely folded pairs of webs are next assembled in superposed relationship with unfolded edge portions of each web projecting beyond the folded edge of the other web of the pair (see web pair A and B and web pair C and D in FIGURE 3). The pairs of webs are then preliminarily interfolded by means of fold II (produced by folding devices 42) whereby a longitudinal edge portion of web B is folded about the previously folded edge of web A and a longitudinal edge portion of web D is folded about the previously folded edge of web C. Here it will be noted that webs B and D are given folds of the same hand and, consequently, all folding devices 42 may be identical. The web pairs are thus prepared for assembly to the moving stack of interfolded webs 47 on conveyor 46.

Sequential assembly of web pairs is effected by fold III, whereby the lower-most web of each pair, webs A and C, have their previously unfolded edge portions folded about an edge of the top-most web on the moving stack 47. As depicted by the dotted-line arrows (FIG- URE 3) indicating conveyor travel, web pair A-B, when assembled to the moving stack, receives the subsequent web pair C-D as fold III is applied to the unfolded edge of web C causing it to wrap around an edge of web B between webs A and B. It should be noted at this point that all of the final interfolds III are of the same hand; in other words, web A is folded in the same direction to join it to the moving stack 47 as is web C in joining the latter web pair to web B. As will appear in greater detail hereinafter, this is important because it enables all of the final interfolding devices 44 to be made of the same hand so that threading fresh webs through these folding devices is a relatively simple operation.

While the above description of the folding method in- D volved in this invention refers to but four webs from four parent rolls, it can be readily appreciated that the operations there described, when successively repeated along a conveyor, are capable of building a stack of interfolded tissue of virtually unlimited size. The method can be practiced on a machine having 100 or more parent rolls on but one face thereof. A similar set of rolls and folding evices may, if desired, be provided on the opposite, or back, face of the machine to double the capacity of the machine.

It will be noted from the lower-most characters in FIGURE 3 that the fully folded webs treated in the above described method have an S-configuration in cross section. This configuration is particularly beneficial for boxed, interfolded facial tissues because the edge fold on the exposed portion of the top-most web constitutes a convenient finger gripping region and facilitates dispensing individual sheets. It can be readily appreciated, however, that the basic principles of this improved method of interfolding can be practiced in the production of, so called, Z-fold inteifolded sheets and in the production of simple V-fold interfolded sheets. In the latter practice the initial edge folds, folds I, are not required and these folds are simply omitted by removing or bypassing

folding devices

33 and 39.

The remaining figures of the drawings illustrate in detail the construction and function of each of the folding devices employed in the apparatus of FIGURE 1. Folding devices 38 and 3? illustrated in FIGURES and 6, respectively, are employed to impart fold I to the webs and, consequently, are employed in aggregate number equal to the number of webs to be handled by the machine.

Folding devices

38 and 39 are similar but of opposite hand. The form of device illustrated in FIGURES 4 and 5 may be designated as being right-hand and has its components arranged to produce a longitudinal fold along the front edge of a web passing thereover, i.e., the edge of the web presented to one viewing the apparatus as it appears in FIGURE 1. The folding device in FIGURE 6 has its components arranged to produce a similar fold along the rear, or back, edge of a web passing thereover, and can be designated as being left-hand.

Folding device 38 comprises a guide plate 51 adapted to have a web trained over the face thereof. The plate 51 has a relatively wide entrance portion 52 which is angularly dispose with respect to and converges into a narrower tail portion 53. Obliquely disposed with respect to the tail portion 53 of plate 51 and positioned in closely space relationship with the back face of this plate portion is a fixedly mounted guide rod 54. Rod 54 is adapted to guide one edge of a web 34 around the adjacent edge or" plate 51 to produce a fold in the web in the manner illustrated in FIGURE 8. It will be noted that a web 3 passed through folding device 38 is bent on a transverse line in its passage from the entry portion 52 to the tail portion 53 of guide plate 51. This bending of the web enables an edge portion of the web to be deflected to the inside of the bend out of the plane of the remaining portions of the web. This bending of the web permits the edge of the web to be folded completely within but a short travel distance of the web without stretching or otherwise unduly stressing the material from which the web is made. The angular relationships between the components of folding device 38 are maintained such that the web portion being folded traverses the same distance in short-cutting the bend and moving to its folded position as do other portions of the web which are not folded. Because all portions of the web passing through device 38 traverse the same distance, there is no tendency for one portion of the web to be stretched or wrinkled with respect to another portion of the web.

The bend-fold principle of web folding just described is employed throughout the several folding devices of this invention in the interest of conserving space occupied by the folding devices and of insuring gentle handling of the webs. This latter consideration is of considerable importance in apparatus designed to handle fragile tissue webs, which have very low tensile strength. The bendfold principle is considered preferable to certain other types of known folding devices wherein portion of the webs are gently urged or coaxed into folded relationship as the web traverses an extended linear or near linear path of travel. These other folding device occupy considerable space, thereby greatly increasing the size of multiple web handling machines and also do not handle the webs with the same dexterity as the folding devices of the present invention.

The folding devices of FIGURES 4 through 8, i.e., both

forms

38 and 39, possess another feature, namely convertibility, which renders the devices capable of folding both longitudinal edges of a web to a conventional C- fold configuration (see FIGURE 11). This feature stems from incorporation of certain movably adjustable components into the folding device. As shown in FIGURES 4- through 7,

folding devices

38 and 39 include a movable guide plate section, or extension, 56 which is adapted to be disposed in coplanar relationship with the edge of guide plate 51 which is opposite the location of fixed guide rod 54. Guide plate extension 56 appears on the right in the right-hand folding device 38 illustrated in FIGURE 5 and appears on the left in the left-hand folding device 39 illustrated in FIGURE 6.

Extension 56 of guide plate 51 is mounted for swinging movement on a tube 57 which supports folding device 38 on the machine frame 31. Extension 56 further includes a detent, indicated generally at 58, which is capable of maintaining the extension in the position illustrated in FIGURES 4 and 5 in which the extension provides support for that edge of the web which is opposite the edge being folded (see FIGURE 8). A spring 5%, also carried by tube 57, biases extension 56 into engagement with its detent 53 but yieldingly permits sliding movement of eX- tension 5e along tube 57 when it is desired to disengage the extension from its detent 58 and move it to an inactive position, such as that illustrated in FIGURE 7.

When guide plate extension 56 is moved to its inactive position, clearance is provided for elevation of a movable guide rod 61, which comprises a stationary lower portion 62 and a movable upper portion 63. Movable portion 63 is biased downwardly to an inactive position by a spring 64 when not in use. The inactive position of guide rod 61 is shown in FIGURE 5 and its active, or raised, position is shown in FIGURE 7. Movable portion 63 is rotatable with respect to portion 62 to position a shoulder 65 thereon to engage a should 66 on portion 62 to retain rod 61 in its active position. Manual rotation of portion 63 to move

shoulders

65 and 66 out of alignment permits portion 63 to retract to its inactive position.

The manner in which folding device 33 imparts a C- fold to a web of material is illustrated in FIGURE 10. It will be noted that both guide

bars

54 and 61 are effective in this operation to guide edge portions of the Web mtg folded relationship with the remaining portions of the we Fold II, by which pairs of webs, such as A and B of FIGURE 3, are preliminarily interfolded, is performed by folding devices 42, one of which is illustrated in FIG- URES 12 and 13. This folding device operates on the same basic bend-fold principle as the folding device described previously and includes a guide plate 67 having an entry portion 63 and a tail portion 69. Folding device 4-2 further includes a single guide bar 71 mounted obliquely adjacent the back face of guide plate 67. Any suitable support such as that indicated at 72 is provided for mounting folding device 42 on the machine frame SI.

The action of folding device ,2 closely resembles that of folding device 38, described previously, with the exception that device 42 receives two webs in face-to-face relationship and in folding one edge portion of the upper web wraps this edge portion about an edge portion of the lo ver web. The folding action is illustrated in FIG- URES l4, l5 and 16, wherein the two webs are identified as A and B, which designations correspond to the design. tions employed in the diagrammatic folding illustration of FEGURE 3.

The final interfold devices 44 which join a pair of previously interfolded webs to the moving stack of webs 47 on conveyor 46 employ a bend-fold principle of fol-ding which differs from that practiced by the previously described folding devices. One of the final interfolding devices is shown in FIGURES 17, 18, and 19 and its folding action is illustrated in FIGURES 20 through 23. This folding device 44 comprises a frame 73 by which the device is mounted on the machine frame 31. A rear upright face 7a of frame 73 acts as an entry guide surface for the major transverse portion of the pair of webs entering this folding device. This portion of the web pair turns to a horizontal path of travel about a tapered roller '76 which is journaled for rotation about a horizontal axis in frame '73. Roller 76 has been determined to be particularly effective for turning the multiple assembly of two prefolde-d webs without wrinkling the Webs at or near their folds. The folding of one longitudinal edge of one of the webs passing through the device 44 is effected by a pan 77 having a guide portion 78 which is slightly oblique with respect to a line parallel to the direction of travel of the multi-web stack 47, extends upwardly and outwardly from a point near one end of roller 76 and presents an edge 79, disposed obliquely with respect to the path of the webs entering the folding device. The unfolded portion of one of the webs passing through device 44- rnakes an initial turn about edge 79 of pan 77 (see FIGURES 18 and 29). Pan 77 also has a horizontal extension 81 having an edge 82 which is oblique with respect to the path of travel of the mu'lti-web stack 47. The edge portion of a web being folded in device ,4 passes around pan edge 7?, follows the rear and lower faces, respectivey, of

pan portions

78 and 81, bends upwardly about edge 32 into a path parallel to the direction of travel of web stack 47 in folded condition. A portion of the top-most web on moving stack 47 is trained over the ripper surface of pan portion 81 with the result that the portion of the web being applied to this stack by folding device 44, and which passes under and around pan portion 81, is folded about an edge of this upper-most web on the moving stack. This is illustrated in FIG-

URES

23 and 24 in which the two webs being assembled to the moving stack 47 are identified as A and B, respectively, and the web stack 47 is shown in dotted lines. Web A has a previously unfolded edge portion folded beneath a portion of the top-most web on the moving stack 47.

The path of web A through folding device 4-4 is illustrated schematically in FIGURE 21 from which it will be noted that one portion, identified as 33, which is traveling along the underface of pan portion 81, is actually moving obliquely with respect to the path of travel of the web as it leaves the folding device. This exit path is, of course, parallel to the longitudinal path of movement of stack .-7 on conveyor 46. As a consequence of this relationship, portion 83 of web A is moving obliquely with respect to a juxtaposed portion of a web on moving stack 47. In order to preclude these relatively moving areas of the two webs from contacting one another, which contact could produce wrinkling or tearing of one web or the other, folding device 54 is equipped with spacer means in the form of a spacer plate 84 which is secured to the lower face of pan extension 81. Spacer plate 8 is provided with a recess 36 in its upper face beneath the region of pan portion 81 over which web A travels. Recess 86 receives portion 33 of the web, as shown in FIGURES 19 and 23.

Folding pan '77 of folding device 44 preferably includes an extension coplanar with portion 81 to the opposite side of slot 8.2 so that a substantially flat surface is provided over which the webs travel. Edge portions of this pan extension 87 are preferably beveled as indicated in FiGURES l7, l9, and 23.

The manner in which a pair of webs, A and B, are directed down nto moving stack 47 and th previously unfolded edge of web A is folded beneath an edge of the top-most web on the stack is sh wn in FIGURE 22. The final configuration of the fully folded and assembled webs is illustrated in FIGURE 24 in which, again, the webs in the moving stack are shown in dotted lines.

it is significant that all pairs of webs entering folding devices have identical fold orientation. Thus, all of the final interfolding devices 3 are of the same hand and can be threaded from the same side, i.e., the front face, of the machine. This feature represents a substan tial improvement over certain prior interfolding machines which were dimcult to thread because the machine tender was required to reach over and behind certain of the interfolding devices in order to thread in a fresh web of material. Although

folding devices

33 and 39, referred to previously, are of opposite hands, their relatively simple construction and their open disposition render all of them relatively easy to thread from the front face of the machine.

Conveyor 46 preferably takes the form of a flexible belt which is resiliently supported from beneath by suitable means such as that illustrated in FIGURE 25 on Sheet 1 of the drawings. The supporting means shown comprises a roller 91 carried by a bell crank 2, which is pivotally mounted on a shaft 93 and biased in clockwise direction by means of a tension pring 94. The construction is such as to urge conveyor id and such iuterfolded webs as may be contained in the stack 47 thereon gently upwardly against a series of rollc s 9-3 which position the top of the moving stack with respect to interfolding device 44. A lurality of these sp'ing biased support rollers 91 are positioned along the length of conveyor 46 so as to support it throu hout its length and permit successive portions of the conveyor to occupy progressively lower positions and thereby compensate for the growth in the height of web stack 4-7 toward the exit end of the conveyor. With the resiliently supported conveyor of the present invention, all interfolding devices 44 can be positioned the same distance above a horizontal reference line, thereby simplifying initial setup and alignment of the machine.

The resiliently supported conveyor 36 of this invention affords the additional advantage of automatically and continuously compensating for variations in thickness, or bulk, of the web material handled by the machine. in spite of close quality control, some variation in material thickness can be expected from various lots of parent rolls. These variations, naturally, result in variations in the thickness of the moving stack 47 during prolonged periods of operations. The resiliently supported conveyor permit the stack to grow or decrease in height without requiring changes in the positions of folding devices The principal benefits and advantages of this invention can be summarized as follows: The method practiced, whereby pairs of webs are preliminarily interfolded prior to bringing them into assembled relationship with other webs on the conveyor, simplifies the final interfold operation performed at the conveyor, i.e., reduces the number of individual operations which must be performed t the conveyor to produce a stack of any given number of Webs. The apparatus required to practice this novel interfolding method is of less complexity than prior interfolding apparatus and employs, to a large extent, relatively simple, easily threaded, foldin devices. Performance of certain folding and inter-folding operations away from the assembly conveyor of the machine admits of these folding devices being stacked or pyramided to achieve compactness of the overall machine. Moreover, these advantages are achieved while yet retaining sur'licient versatility of the apparatus to permit it to be converted to the production on non-interfolded stacks of webs and of insuring careful handling of the web material during both conditions of operation.

What We claim is:

1. In apparatus for forming stacks of folded Webs, the combination of a conveyor for a stack of folded webs, a preliminary folding device adapted to have a web passed thereover, said folding device being capable of alternative- 13/ folding one or both edge portions of the web conveyed thereover, final folding means disposed adjacent the stack of webs on said conveyor, said final folding means being adapted upon receiving a Web having but one folded edge portion to fold the other edge portion of said web about an edge portion of the top-most Web on said stack of Webs and upon receiving a web having both edge portions folded of guiding said web onto the top-most web on said stack of webs, and means for adjusting said preliminary folding device to thereby set the apparatus for the production of a stack of interfolded Webs or the production of a stack of non-interfolded Webs.

2. A folding device for interfolding with a longitudinally moving stack of interfolded webs of flexible material another web moving obliquely toward and onto said stack of webs comprising means for folding and guiding a longitudinal edge portion of said other Web beneath an edge portion of the top-most web on said stack, said means directing said other web through a path, at least a portion of which extends obliquely with respect to the direction of movement of said stack, and spacer means adjacent said folding means and disposed between said obliquely moving portion of said other web and the next-to-topmost web in said stack for preventing contact between said obliquely moving portion of said other web and the nextto topmost web in said stack.

3. In a device for folding longitudinal edge portions of a web conveyed thereover, the combination of a guide plate having entrance and exit portions obliquely disposed with respect to one another, the construction and arrangement of said guide plate being such that a web passing over the convex face thereof executes a bend which is transverse of the web, a turning member positioned adjacent one edge of said guide plate and obliquely disposed with respect to the path of travel of a web over said guide plate, said turning member deflecting a longitudinal edge portion of said web about said one edge of the guide plate, a second turning member and means supporting said second turning member for movement into and away from a position adjacent the opposite edge of said guide plate, said second turning member when positioned adjacent said opposite edge of said guide plate being effective to deflect another longitudinal edge portion of said web to fold other said web portion about said opposite edge of said guide plate.

4. In a device for folding longitudinal edge portions of a web conveyed thereover, the combination of a guide plate having entrance and exit portions obliquely disposed with respect to each other, the construction and arrangement of said guide plate being such that a web passing over the convex face thereof executes a bend which is transverse of the web, a turning member positioned adjacent one edge of said guide plate and obliquely disposed with respect to the path of travel of .a web over said guide plate, said turning member deflecting a longitudinal edge portion of said web to fold said web portion about said one edge of the guide plate, a guide plate extension adapted to occupy a position adjacent the opposite edge of said guide plate, means supporting said extension and permitting movement of the extension away from said guide plate, a second turning member and means supporting said second turning member for movement into and away from a position adjacent said opposite edge of said guide plate in a region occupied by said plate extension when the extension is disposed adjacent said guide plate, said second turning member when positioned adjacent said opposite edge of said guide plate being effective to deflect another longitudinal edge portion of said web to fold said other web portion about said opposite edge of said guide plate.

5. In apparatus for folding webs of flexible material to provide a multiple stack of interfolded webs, the combination of an assembly conveyer, a first set of folding devices spaced from said conveyer, all of said folding devices of said first set being of the same hand, means for supplying a pair of webs to each folding device of said first set, each folding device of said first set folding a longitudinal edge portion of one web of the pair about a longitudinal edge portion of the other web of the pair, and a second set of folding devices arranged along said conveyor, all of the folding devices of said second set being of the same hand and of the hand opposite to said first set of folding devices, each of the folding devices of said second set being positioned to receive a prefolded pair of webs from one of the folding devices of said first set, each folding device of said second set including means for folding a longitudinal edge portion of the said other web of the pair passing therethrough about a longitudinal edge of a web previously directed onto said conveyor.

6. Apparatus as set forth in claim 5 in which said Web supplying means comprises a stand and a plurality of rolls of web material carried by said stand in stacked relationship above said assembly conveyer and wherein said first set of folding devices are disposed beneath said rolls and above said conveyer.

7. In apparatus for folding webs of flexible material to provide a multiple stack of interfolded webs, the combination of an assembly conveyer, a first set of folding devices spaced from said conveyer, means for supplying a web to each folding device of said first set, said first set of folding devices alternately folding opposite edge portions of successive webs, a second set of folding devices spaced from said conveyer, each folding device of said second set being positioned to receive a pair of oppositely folded webs from two of the folding devices of said first set, all of the folding devices of said second set being of the same hand, each folding device of said second set folding an unfolded longitudinal edge portion of one web of the pair passing therethrough over a folded longitudinal edge portion of the other web of the pair, and a third set of folding devices arranged along said conveyer, all of the folding devices of said third set being of the same hand and of the hand opposite to the folding devices of the second set, each folding device of said third set being positioned to receive a prefolded pair of webs from one of the folding devices of said second set and including means for folding an unfolded longitudinal edge portion of the said other web of the pair passing therethrough about a folded longitudinal edge of a web previously directed onto said conveyor.

8. Apparatus as set forth in claim '7 in which said web supplying means comprises a stand and a plurality of rolls of web material carried by said stand in stacked relationship above said assembly conveyer and wherein said first and second sets of folding devices are disposed beneath said rolls and above said conveyer.

References Cited by the Examiner UNITED STATES PATENTS 229,479 6/80 Scholfield 27094 654,515 7/00 Casterline 270-40 770,508 9/04 Sexton 270-40 2,642,279 6/53 Teall I 27040 3,066,932 12/62 Greincr et al. 270-40 EUGENE R. CAPOZIO, Primary Examiner.

R. A. LEIGHEY, WILLIAM B. PENN, Examiners.

Claims

1. IN APPARATUS FOR FORMING STACKS OF FOLDED WEBS, THE COMBINATION OF A CONVEYOR FOR A STACK OF FOLDED WEBS, A PRELIMINARY FOLDING DEVICE BEING CAPABLE OF ALTERNATIVE THEREOVER, SAID FOLDING DEVICE BEING CAPABLE OF ALTERNATIVELY FOLDING ONE OR BOTH EDGE PORTIONS OF THE WEB CONVEYED THEREOVER, FINAL FOLDING MEANS DISPOSED ADJACENT THE STACK OF WEBS ON SAID CONVEYOR, SAID FINAL FOLDING MEANS BEING ADAPTED UPON RECEIVING A WEB HAVING BUT ONE FOLDED EDGE PORTIN TO FOLD THE OTHER EDGE PORTION OF SAID WEB ABOUT AN EDGE PORTION OF THE TOP-MOST WEB ON SAID STACK OF WEBS AND UPON RECEIVING A WEB HAVING BOTH EDGE PORTIONS FOLDED OF GUIDING SAID WEB ONTO THE TOP-MOST WEB ON SAID STACKD OF WEBS, AND MEANS FOR ADJUSTING SAID PRELIMINARY FOLDING DEVICE TO THEREBY SET THE APPARTUS FOR THE P OF A STACK OF INTERFOLDED WEBS OR THE PRODUCTION OF A STACK OF NON-INTERFOLDED WEBS.