Method Of And Apparatus For Producing Stacks Of Folded Sheet Material

Abstract

Stacks of folded sheets with a C-fold, Z-fold, V-fold or other various kinds of folds are formed from a plurality of webs of flexible sheet material such as paper toweling or creped tissue. To form the stacks of folded sheets, the webs are longitudinally folded while traveling along a path to an accumulator at which the folded webs travel about a closed path a plurality of times and accumulate as a multiple series of webs stacked in an endless log. The endless log is severed at spaced intervals to form a plurality of individual stacks of folded sheets. When it is desired to interfold the sheets throughout the stack, the series of folded webs are first interfolded with each other while traveling to the accumulator whereat a portion of an outer one of the incoming series of webs is interleaved with a portion of an outer web of the partially formed log completing one revolution about the closed path on the accumulator.

Description

This invention relates to a method of and an apparatus for producing stacks of folded sheet material from one or more webs of flexible sheet material such as paper toweling, tissue or other cellulosic materials.

Paper toweling, facial tissue, toilet tissue and other sheets of such material are often sold as stacks of individual folded sheets which are packaged or banded. The particular shape of the fold of the sheet material varies and is commonly known as C-folds, Z-folds, V-folds or other types of folds. In many instances, the sheets are interfolded with a portion of one folded sheet interleaved with a portion of another folded sheet so that drawing of one sheet from a dispenser causes a portion of another succeeding sheet to project outwardly for grasping for pulling from the dispenser. Such packs or bands of folded sheets often come in large stacks with as many as 100 to 400 sheets in a given stack. In addition to producing such stacks at high speed and economically, it is most desirable that the stacks be formed uniformly for banding or packaging and without wrinkles in the sheets as would disturb the end user of the folded sheets.

A number of proposals have been made heretofore for folding individual long webs of cellulosic material into the various folds and then for ultimately forming stacks of the folded webs which are eventually severed into individual lengths to form the desired size sheet which is ultimately packaged and sold.

The present invention is directed to providing a new and improved method and apparatus which folds the webs and assemblies them into stacks at high speeds for commercial production while avoiding wrinkling, creasing or breaking of the individual webs. Additionally, the illustrated apparatus may be used to form various stacks with various types of folds and may be used to form either interfolded or non-interfolded stacks of folded webs. Thus, a common apparatus may be used to make production runs of various sheet folds and either interfolded or not interfolded.

Accordingly, a general object of the invention is to provide an improved method of and apparatus for producing stacks of folded sheet material of the foregoing kind.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings in which:

FIG. 1 is a diagrammatic illustration of an apparatus for practicing the method for producing stacks of folded sheets from elongated webs of sheet material;

FIG. 1A illustrates diagrammatically several stacks and sheet folds formed by the apparatus of FIG. 1;

FIG. 2 is a side elevational view of a parent roll at a folding station for forming longitudinally extending folds in the webs;

FIG. 3 is an enlarged diagrammatic view of a manner of interfolding sheets having Z-folds therein;

FIGS. 4 and 5 illustrate a lay down conveyor for use at the folding station;

FIG. 6 is a cross-sectional view taken substantially along the line 6--6 of FIG. 4 showing a cross section of the lay down conveyor;

FIG. 7 illustrates an enlarged view of sections of the lay down conveyor;

FIG. 8 is a side elevational view of a pull means for drawing a series of webs through the folding station;

FIG. 9 is an elevational view of an accumulator constructed in accordance with an illustrated embodiment of the invention;

FIG. 10 illustrates a trusswork used in the wheel of FIG. 9;

FIG. 10A is an enlarged cross-sectional view of the wheel rim;

FIG. 10B is a cross-sectional view of a stack flattener means for the webs accumulated on the accumulator;

FIG. 10C is a fragmentary perspective view of a pivotal support for the stack flattener means of FIG. 9;

FIGS. 11, 12 and 13 illustrate a means for combining a series of incoming webs with a stack of webs on the accumulator;

FIGS. 14, 15 and 16 illustrate an interfolding means for interfolding one of the incoming webs with one of the stacked webs on the accumulator;

FIG. 15A is a cross-sectional view taken substantially along the line 15A--15A of FIG. 14;

FIG. 17 illustrates an interfolding means for V-fold webs;

FIG. 18 is a plan view of a rim driving means for the accumulator wheel;

FIG. 19 is a partial and diagrammatic illustration of an integrated drive for the apparatus of FIG. 1;

FIG. 20 is a side elevational view of a drive for a tire;

FIG. 21 illustrates a disk brake for a drive tire;

FIG. 22 illustrates a drive mechanism for web feed belts at the folding station;

FIG. 23 illustrates a drive mechanism for web fed belts at the folding station;

FIG. 24 illustrates a cutting means for cutting the annular log;

FIG. 25 is a side elevational view of the compressor conveyor for compressing a log;

FIG. 26 is a perspective view of an automatic wrapping means for the log;

FIGS. 27 and 28 are diagrammatic perspective views of a folding means and shoe for the wrapping webs;

FIG. 29 is a side elevational view of a conveying means for a log at a severing station;

FIG. 30 illustrates a drive means for intermittently driving the conveying means of FIG. 29;

FIG. 31 is another plan view of the portion of the drive means shown in FIG. 30; and

FIG. 32 is a side elevational view of means for rotating and oscillating a blade for severing the log.

As shown in the drawings for purposes of illustration the invention is embodied very generally in an apparatus 11 for producing individual stacks 13a, 13b, 13c or 13d of folded sheets 15a, 15b, 15c, etc. with a large number of sheets such as, for example, 100 to 400 sheets in each stack. Each of the sheets in the stack has a fold or folds therein with the sheets having various shapes, for example, a conventional, V-fold, C-fold, Z-fold or other kind of fold. Also, the folded sheets may either be stacked with or without interfolding between adjacent portions of adjacent sheets in the stack. The preferred method practiced by the apparatus 11 comprises the following steps: each of a series (usually more than one) of webs 17a, 17b, 17c, etc. of paper or other flexible thin sheet material are folded continuously and with a longitudinal fold at a folding station 19 while traveling along a predetermined path of travel towards an accumulating station 21 at which the series of folded webs travel about a closed path a plurality of times to form a stack of the series of folded webs constituting an endless log 25 of stacked folded webs. The log 25 is subsequently severed at a plurality of spaced and predetermined locations to form the individual convenient lengths for the folded sheets and to form a plurality of individual discrete stacks of folded sheets from the log 25.

In the preferred method, the endless log 25 is formed on an accumulator 27 in which the closed path is circular and on a circular accumulating wheel 28 to form a log having a dimension about equal to the circumference of the accumulator wheel, for example, 100 feet. In the illustrated method, the log 25 is first cut by a cutting means 29 and then removed from the accumulator station 21 and subsequently banded with a band 31 before being severed into the individual stacks 13a, 13b, 13c or 13d by a severing means 30. Also, in accordance with the illustrated method, the cut log is transferred from the accumulator 27, straightened, and automatically banded with one continuous band 31 while traveling through a banding station 32. After banding, the banded log 25 is severed by a severing means 33 which cuts through the band 31 and log 25 at spaced intervals to form the desired length of divided banded stacks 13a, 13b, 13c or 13d.

The accumulator 27 provides an efficient manner for neatly aligning and stacking the incoming webs 17a, 17b, 17c, etc. into a stack having its height increased by the number of folded webs in the incoming stream or series of webs for each lap or revolution about the closed path. In the illustrated examples, a series of seven to 10 webs are superimposed and the accumulator wheel 28 is revolved 25 times before stopping to form stacks of 175 to 250 folded sheets in the log 25 and also in the ultimately formed banded stacks.

In accordance with an important aspect of the invention, the banded stacks 13a, 13b, 13c or 13d may have the sheets 15a, 15b, 15c, etc. interfolded through the height of the log and stacks. To this end, in the preferred method, the individual webs, for example, each of the seven Z-fold webs 17a-17g are interfolded with one another at the folding station 19 by interfolding devices 34, as best seen in FIG. 2, in the form of a set Z-folding shoes 35. The series of seven, superimposed folded webs is then brought to the accumulating station 21 wherein an outermost fold or edge portion, for example, edge portion 40 of web 17g as best seen in FIG. 3 is, upon making one revolution about the closed path of the accumulator 27, brought into interfolded relationship with upper fold or edge portion 41 of the uppermost web 17a of the incoming series of seven interfolded webs 17a-17g. As will be explained in detail, an interfolding means 43 opens a trough between the lowermost folds 40 and 40a of the lowermost web 17g in the partially formed log 25 and a trough between the upper two folds 41 and 41a in top web 17a in the incoming series of webs and interleaves the folds 40 and 41 near the intersection of the closed path and the straight line feed path of the incoming webs. Preferably, the interfolded relationship between the incoming webs and the stacked webs on the accumulator 27 occurs along a tangent line to the wheel 28 at a tangent point 47. Thus, in the example disclosed, at or closely adjacent the tangent point 47 each seventh web (17g) in the stack of webs on the accumulating wheel completing its first lap about the closed path is interfolded with its next lower incoming web (17a) on the straight line feed path by the interfolding means 43. The other webs were, as stated above, interfolded to each other by the interfolding devices 34 prior to reaching the accumulating station 21.

Referring now more specifically to the illustrated and specific features of the invention, at the folding station 19 one set of folding shoes 35a, 35b, 35c or 35d having a folding shoe for each web, forms the continuous longitudinal fold or folds in the webs 17a, 17b, etc. drawn through the folding station. The preferred and illustrated folding devices are those of the type disclosed in copending application entitled "Web Folding Apparatus and Method" of Charles A. Lee, Warren R. Furbeck and Horace M. Kemp, application Ser. No. 114,994, filed Feb. 12, 1971, which application is incorporated herein by reference it is fully reproduced herein. The illustrated apparatus is designated as being a vari-fold apparatus in that with a minimum of changes, principally at the folding station 19, the series of webs discharging from the folding station 19 may have a C, V, Z-folds, or another version of the Z-fold herein termed a Z-1 fold. Also, at the folding station, a parent roll 51 of paper stock is associated with a given set of folding shoes. To provide a long continuous supply source of sheet material at the folding station 19, it is preferred that the parent rolls 51 be slit into a plurality of webs 17a, 17b, 17c, etc., each leading to one of the associated folding shoes of its associated set.

As best seen in FIG. 2, each parent roll 51 is supported for rotation about a horizontal axis in a frame means 53 with a strip 55 of sheet material being stripped therefrom and fed at a constant velocity by means of a pair of endless feed drive belts 57 bearing against the periphery of the parent roll to continuously rotate the roll in a counterclockwise direction as viewed in FIG. 2. In this instance, the strip 55 of paper stock is directed downwardly from the parent roll to travel beneath a direction changing roll 59 and then travels upwardly past a bowed rod 61 for smoothing the strip and then about the upper side of a driven feed roller 63 to a slitting station 65.

At the slitting station, the strip 55 from the parent roll is slit by a plurality of slitter discs 67 spaced along the width of the strip 55 and cooperating with a hard ceramic anvil roller 73 to form the series of webs e.g., webs 17a-17g for folding by the respective Z-folding shoes 35a. By way of example, the illustrated parent roll 51 may be 100 inches weide with the slitter discs 67 spaced 14 inches apart slitting an inch wide waste web on each end of strip 55 with seven 14 inch wide webs 17a-17g formed and fed into the set of seven folding shoes 35a to form the Z-folds in each of the webs 17a-17g. For the V-fold shoes 35b, the strip 55 from the associated parent roll is slit into 10 strips and 10 folding shoes are provided in the set of folding devices 35b. Thus, it will be seen that the number and width of each web of the series of folded webs issuing from the folding station 19 may be varied. As disclosed in the aforementioned patent application the V-fold webs are alternately folded with left and right hand folds and are interfolded as the ten webs leaving the V-fold shoes 35b. The C-fold shoes form webs which are not interfolded. Both sets of Z-fold shoes 35a and 35d provide a series of interfolded webs.

To assure that the folded webs 17a-17g are properly aligned along a straight line which is tangent to periphery of the accumulator wheel 28, the inner edges 75, as best seen in FIG. 2, of the webs 17a-17g from any of the sets of folding devices 35a-35d are laid one on another on a laydown conveyor 74 and against a common vertically extending guide plate 77 on the laydown conveyors. More specifically, a first folded and/or interfolded web is laid down by its folding shoe on a continuously moving endless conveyor belt 83 supported on a dead plate 85 of the laydown conveyor means and the other webs are then laid thereon. The endless conveyor belt 83 extends beneath each of the sets of folding devices to receive the folded series of webs along its upper substantially horizontal run to discharge the same at idler rollers 87 from which the belt 83 turns downwardly about another idler roller 88 to return to tension rollers 89 and 90 prior to returning to rollers 91 and 92 which guide the endless belt upwardly to provide a space through which workers may bend and cross underneath the conveyor means. The belt 83 continues to another set of downwardly guiding rollers 93, 94 to travel past guide rollers 95 and 96 to an upper drive roller 97, which drives the belt along its upper forward run. The laydown conveyor belt 83 is sufficiently long to pass beneath each of the respective sets of folding devices and is sloped gradually downwardly from the horizontal to accommodate the increasing thickness of webs being laid thereon.

Preferably, the laydown conveyor belt 83 is also vertically adjustable to accommodate different stack heights for the varying numbers of webs and the different kinds of folds therein. To this end, as best seen in FIG. 6, a jack mechanism 98 is provided to move the dead plate 85 vertically relative to a stationary frame 99 for the laydown conveyor means. More particularly, the jack mechanism includes a handle 100 for manual turning which is connected to a jack 101 having a jack screw 103 extending vertically to a pivoted connection 105 with a rectangular shaped channel 107 carrying the dead plate 85 thereon. As best seen in FIG. 7, the dead plate 85 is formed of a connected series of plates 85 carried on several interconnected channels 107 which have interleaved portions 109 each with aligned elongated slots 111 therein through which slots extend connecting pivot pins 113. Thus, by turning the jack mechanism respective sections of the conveyor may be adjusted angularly and vertically relative to other conveyor sections to provide a continuous but adjustable path and height for the conveyor belt 83.

To draw the respective webs 17a, 17b, 17c, etc. through the folding sheets at the folding station 19 and overcome the frictional resistance and resistance of the webs to changing shape, the latter are carefully tensioned and pulled by a draw or tension means called a pull means 111 hereinafter. The preferred pull means 111 also controls the bulk, i.e., the height of the series of webs 17a, 17b, 17c, etc. traveling to the accumulating station 21 and hence effects the stack height of the log 25 on the accumulator 27. The pull means 111 is provided intermediate the folding station 19 and the accumulator 27. As will be explained in greater detail when describing the integrated drive system for the various mechanisms and devices, the pull means 111 for the stack of webs is driven by a common drive for the accumulator 27 and its speed relative to the speed of web feed at the folding station may be adjusted so that a desired tension is maintained for the series of webs 17a-17g jumping a gap 112 (FIG. 1) between the laydown conveyor 74 at the folding station 19 and the pull means 111. Adjusting of the speed of the pull means is also important in controlling the tension of the series of webs to assure smooth passage through the means 43 and good stack formation on the accumulator wheel 28.

The illustrated tension and draw means 111 comprises, as best seen in FIG. 8, an upper pull belt 115 which cooperates to form a nip with a lower endless feed belt 117. The upper pull belt 115 is carried in an upper frame means 116 and extends between an upper idler roller 119 rotatable about a horizontally disposed axle 150 at the discharge end of the pull means and a forward drive roller 121 at an inlet end of the pull means 111. To prevent wrinkling of the webs, the upper pull belt 115 is guided gradually at its inlet end downwardly to engage the webs along a downwardly inclined path from drive roller 121 to converge at a first idler roller 123 with the top of the series of webs 17a-17g supported on the lower belt 117. The upper pull belt 115 travels along its lower feed run across a series of idler rollers along a generally horizontal path parallel to the lower pull belt 119 until reaching the discharge idler roller 123 whereupon the upper pull belt travels upwardly to the idler roll 119. Thus, the upper belt is guided into gradual frictional contact with the top of the series to compress the webs against the lower pull belt 117 and to exert a frictional pulling force to draw the webs through a set of folding devices.

The amount of compression force exerted on the series of webs 17a-17g by the upper pull belt 115 is controlled by a lift means 125 which lifts at least a portion of the weight of the upper frame means 116 and also lifts the upper pull belt 115. The illustrated lift means comprises two expandable pneumatic lifts 127, each resting on a horizontal cross beam 129. The beams 129 are fixed at opposite ends to a pair of vertically upstanding columns 131 which rest on the floor 133. The uppe frame means 116, which carries the conveying belt 115 and its rollers 119 and 121, includes an overhead beam structure 137 having pads 139 resting on the two lifts 127 with the beam structure 137 being freely movable vertically relative to the columns 131 with adjustment of the lifting force from the two lifts 127. The portion of the weight of the frame means 116 lifted by the lifts 127 is controlled by adjusting a valve means 141 in a compressed air line 143 which leads to the lifts 127. The frame further includes front and rear pairs of vertical support pillars 145 and joined to fore and aft extending lower beams 147 carrying the axles for the upper belt rollers 119 and 121.

The upper pull belt 115 is tensioned by adjustment of its inlet end roller 121 upon turning an adjustment screw means 149 which comprises a screw 149a connected to axle 120 and threaded in a nut 149b on the lower beam 147. By turning the screw, the axle 120 may be shifted fore or aft to change its position relative to an axle 150 for the outlet belt roller 119. The belt roller axle 150 has secured thereto a drive sprocket 151 about which is entrained a drive chain 153 extending downwardly to a drive sprocket 155 mounted on a shaft 156 carried by a pivotally mounted bracket 154 which pivots about a rotatable drive shaft 157 mounted in the stationary frame for the pull means 111. The axles 150 and shaft 156 are maintained at a fixed distance by a link 159 fastened at opposite ends therebetween. When the upper frame means 116 is shifted vertically by the lifts 125, a gear 161 fixed to the shaft 156 rolls about the surface of adjacent drive gear 162 while maintaining a meshed relationship therewith. Thus, the input torque to the drive shaft 157 turning the gear 162 will be imparted to the meshed gear 155 to turn the chain sprocket 155 despite shifting of the upper frame means 116.

To prevent the upper pull belt 115 from traveling downstream and carrying the upper frame means 116 with it, the upper frame means 116 is held by a pair of links 164 which are pivotally connected at their forward ends 164a to the forward pair of columns 131. Rearward ends of the links 164 are pivotally connected by pins 164b to horizontal beams 147. The links 164 will pivot to allow vertical shifting of the upper frame means 116 and yet will hold the latter against walking forwardly with the series of webs 17a-17g being drawn from the laydown conveyor 74. The upper frame means 116 is constrained against lateral shifting by means not shown.

The lower pull belt 117 is generally horizontally disposed and has an upper reach guided for horizontal movement across a series of horizontally disposed idler rollers 163 from an input drive roller 165 to an output roller 167 at the discharge end of the tension and drawing means 111. The roller 165 is provided with a tension adjusting means 149 to control the tension in the lower pull belt 117 in the manner described above for the upper pull belt 115.

Referring now in greater detail to the illustrated accumulator 27, the incoming folded webs 17a-17g are wound numerous times thereon into a stacked condition to form the log 25. For instance, when the accumulator 27 is used to form stacks of C-folded paper towel sheets, the paper towel webs 17a-17g are accumulated in a log having a height of 9 or 10 inches. Later, the C-fold web log 25 will be compressed to and retained by its band 31 at a height of about 7 inches which is about the maximum for a conventional dispenser for such C-folded paper towel sheets. In the illustrated examples of the invention, the typical rotation of the accumulator wheel is 25 revolutions between start and stopping which gives a sheet count of 175 to 250 sheets depending upon the number of webs in an incoming series. Manifestly, the number of incoming webs may be varied from one to more than that described herein and the number of cycles about the closed path may also be varied from that described and still be within the scope of the present invention.

For the purpose of providing a relatively long log 25 which can be severed, e.g., into 100 or more individual stacks 13a, 13b or 13c, the illustrated accumulator 27 is about 30 feet in diameter and provides a 100 foot circular log 25 prior to its removal and straightening. Because of the large diameter and also because of the relatively high speed operation desired for paper products, for example, 700 feet per minute velocity, the accumulator wheel 28 is sturdily built, carefully governed in its path of rotation and brought up to speed and stopped with controlled acceleration and deceleration. To these ends, the accumulator wheel is constructed, as best seen in FIG. 1, with a central hub 171 rotatable about a vertical central axis through a central support shaft 173 mounted in an upstanding support 175. From the hub 171 are a series of radially extending struts 177 which extend outwardly from the hub 171 to a log-carrying rim 178. The struts 177 are preferably in the form of trusses to provide a sufficient rigidity for the relatively wide diameter wheel. For example, as best seen in FIGS. 9 and 10, the wheel struts 177 comprise a lower truss beam 179 which is disposed generally horizontal and extends from the hub 171 to the rim 178. Above the lower truss beam and joined thereto by intermediate vertical rods 183 is upper truss beam 181. The upper truss beam extends radially outwardly and downwardly from the top of the hub to join the lower truss beam at the rim 178. The hub 171 is preferably formed of a generally rectangular trusswork 185 carrying bearings 186 journaling the wheel 28 on the post 173. In addition to the trusses 177 described above, the accumulator wheel may be provided with a series of push-pull spokes 187 having a length adjusting turn buckle arrangement 189 fastened at an end to a pad 199 on the rim 178 and an inner end fastened to the hub 171. By adjusting the length of the spokes 187, the rim may be moved more closely into a true circular configuration.

It will be appreciated that high speed and over a number of revolutions the edges of the incoming webs 17a-17g and the uniform positioning of the webs in the log 25 depend upon having a uniform path, in this instance, a circular path. To assure a precision circular path at a relatively low cost, the weheel rim 181 preferably is made of arcuate shaped metal sections 200 joined to each other and to the trusses 177 and spokes 187 to form a generally circular rim 178 on which is then machined a precise circular web aligning annular surface 201, the latter preferably machined after the accumulator wheel is assembled and while it is rotating. The circular web engaging surface 201 (FIG. 10A) is formed, in this instance, by machining a build-up layer 202 on the outer side of the metal sections. The layer 202 comprises an inner fiberglass layer, an intermediate putty layer and an outer fiberglass layer to provide about a three quarter inch build-up beyond the metal sections 200. Then, by mounting a lathe type cutter blade (not shown) with its tip cutting into the build-up layer 202, the outer web engaging surface 201 may be machined by cutting the high spots from the layer and also by assuring there are no low spots present so that tool cuts completely for 360.degree. of the layer 202 turning therepast. Then by moving the tool vertically, the entire web engaging surface, usually twelve inches in height may be obtained.

The accumulator wheel 28 is also provided with caster wheels to prevent wobbling of the rim 178. For instance, at about four equally spaced locations there are horizontally disposed supporting caster wheels 203 mounted for rotation on vertical axles 204. These support the weight of the rim in addition to the trusswork and hence help prevent any bouncing up and down. To assist in preventing shaking and wobbling of the rim, the rim is also provided with a downwardly extending driving flange 205.

The incoming series of the webs 17a-17g are transferred from the pull means 111 and stacked on the accumulator 27 with their inner and outer edges neatly aligned with the webs already stacked in the log and in a continuous manner by the stack separator or interfolding means 43 which, as explained before, may interfold a portion of the incoming webs with the webs already on the turntable accumulator 27 or simply stack the webs when the webs are not interfolded as with the C-fold webs. It will be recalled that the inside edges 75 of the series of webs issuing from the folding station 19 have their edges aligned by a vertical guide 77 to be aligned with a tangent to the wheel periphery at the point 47. These webs leaving the pull belts 115 and 117 jump a slight gap 211 to the means 43 which supports the series of webs as they move the final short distance to the tangent point 47. Preferably, the gap 211 (FIG. 11) is kept quite narrow and the webs are kept tensioned with a controlled amount of tension between the accumulator 27 and the pull means 111 by adjusting their speeds relative to each other so that the webs on the flange support 212 of the acculator 27 will separate from the flange support and travel smoothly through the means 43 and so that the incoming webs will not lose their folds and will readily combine with the stacked webs. The tension of the incoming series of webs 17a-17g is also important to formation of a good flat condition for the webs on the accumulator wheel 28. If the incoming web tension is insufficient, the inner edges 75 of the webs tend to rise along the annular surface 201 making an uneven stack. Alternatively, loosely tensioned webs may lose their folds while passing through the interfolding means 43. On the other hand, if the web tension is too great, the stacked webs tend to bind on the annular surface 201 of the wheel 28 or to resist lifting by bunching when pulled through the interfolding means 43.

To overcome these problems, the apparatus 11 is provided with a tension means 206, as best seen in FIG. 1, which measures the tension in the webs 17a-17g at a gap 211 between the pull means 111 and the interfolding means 43 and allows control of tension within certain prescribed upper and lower limits. Herein, the tension means 206 comprises a feeler 207 engaging the top of the series of webs and its displacement by the webs is measured by a load cell 208 which operates a meter 209 to give a tension indicating reading. By empirical methods, the operator will establish proper upper and lower limits of tension. When the operator observes that the tension is approaching a limit condition, the operator will operate an adjustable speed control device for the pull belts 115 and 117 to change the speed slightly of the pull belts relative to accumulator wheel's speed of winding whereby the tension in the incoming webs 17a-17g is adjusted.

The flange support 212 is preferably coplanar with the lower pull belt 117 and with a top surface of a supporting plate 213 of the interfolding means 43 so that the incoming series of webs are supported and transferred readily onto the support flange. Preferably, the flange support 212 is sufficiently wide, e.g. 5 1/2 inches, to accommodate the widest of the folded webs which are 5 1/4 inches in width. As illustrated, the support flange is substantially normal to the annular web engaging surface 201 on the accumulator wheel so that the stack of webs is formed with their inner and outer edges substantially aligned through the height of the log 25. Also, the smaller width of webs, for example, the 3 1/2 inch Z-fold webs 17a-17g are supported on the flange support 212 with the inner edges against the surface 201 and their outer edges spaced inwardly of the outer edge of the flange support 212.

Referring now in greater detail to the means 43, it may take the form shown in FIGS. 11, 12 and 13 where it performs no interfolding function or the form shown in FIGS. 14, 15 and 16 which the webs are interfolded with those on the log being formed on the accumulator wheel. In either event, in the preferred embodiment of the invention, the stack of webs on the flange support 212 forming a partial log 25 are lifted and the incoming series of webs 17a, 17b, 17c, etc. discharging from the pull belts 115 and 117 are placed beneath the lowermost web of the stack on the flange support 212. As best seen in FIGS. 11, 12 and 13, the stack of webs are lifted by an inclined cam or lifter 216 which has an upstream free end 221 disposed closely adjacent the top of the flange support 212. The partially formed log is cammed upwardly along the lifter 216 to a bend 219 at which the lifter joins a horizontal stack support plate 215 which holds the stack for travel above the flange support 212 on the accumulator wheel. The leading edge of the lifter 216 may be beveled to assist in lifting the lowermost web of the log 25 being formed and camming the same upwardly along the upper surface of the lifter 216 to be spaced above the incoming series of webs 17a, 17b, 17c etc. which are traveling into a space 223 between the stack support plate 215 and a lower web support plate 213. The partially formed log travels across the plate 215 in an arcuate path past the tangential point 47 to discharge at an end 224 thereof at which time the log is free to travel down onto the incoming webs which are now resting on the flange support 212 of accumulator wheel.

More specifically, the stack support plate 215 and web support plate 213 are spaced vertically and held in parallel relationship to each other by a triangular shaped spacer block 225 which extends from about the area of the bend 219 to closely adjacent the tangential point 47 and within the space between the wheel 28 and travel path of the inner edges 75 of the webs so as not to interfere with the incoming webs moving through the space 223 between plates 213 and 215. Preferably, the plates 213 and 215 have inner arcuate edges 217 disposed closely adjacent the annular surface 201 on the wheel. THe lower web support plate 213 is provided with a discharge end 227 adjacent the discharge end for the stack support plate. The plate 213 is provided with a wide outward portion to the underside of which is secured a mounting block 231 fastened to a stationary frame. In this manner, the means 43 may be mounted adjacent the accumulator wheel 28. In this manner, the C-folded webs are thus accumulated continuously throughout and for each revolution of the accumulator wheel 28.

The incoming webs 17a, 17b, 17c, etc. could be stacked in different manners, for example, on top of the stack. In any event, the incoming webs and the webs on the wheel 28 are confined and guided and tensioned to lie flat when being combined.

The interfolding of the incoming series of webs 17a-17g with the stacked webs forming a partial circular log on the accumulator 27 will be described in conjunction with the interfolding means 43 illustrated in FIGS. 14-16. The latter means will be referred by the same reference characters applied above for the means illustrated in FIGS. 11-13; but with a subscript a added for elements similar to those elements previously described. The interfolding is accomplished in this instance by opening a trough 232, as best seen in FIGS. 15 and 15a, between the upper fold 41 of the incoming web 17a and its adjacent underlying fold 41a and also likewise forming an open trough 233 between the lowermost fold 40 of the lowermost web 17g of the log 25 and its adjacent fold 40a. After opening the troughs 232 and 233 the webs are guided along opposite sides of an inclined interleaving plate 235 from the position shown in FIG. 15 to the position shown in FIG. 15a in which the folds 40 and 41 are substantially overlapped while still separated by the interleaving plate 235, as best seen in FIG. 15a. The stack of webs traveling across the upper stack support 215a are then discharged at its discharge end 224a to travel down and join the incoming webs therebeneath with the fold 41 of the web 17a being interleaved between the web folds 40 and 40a of the lowermost web 17g of the partially formed log now resting on incoming web 17a leaving the interfolding means 43.

Referring now in greater detail to the preferred manner of joining the Z-fold webs in an interfolded relationship, the stack of webs on the flange support 212 of the wheel 28 is lifted upwardly by the upwardly inclined cam lifter 216a with the fold 40a being disposed generally horizontally, as best seen in FIG. 15 on the upper side of the lifter while the lowermost fold 40 is brought about a corner 239, which joins the stack plate and interleaving plate at inner arcuate edges thereof, and extends along the underside of the interleaving plate 235. Preferably, the interleaving plate 235 opens the trough 233 between the folds 40 and 40a as illustrated prior to approaching the tangent point 47.

At the same time, the incoming webs 17a-17g travel across the gap 211 from the pull means 111 to the web support plate 213a and travel across its upper surface with the upper fold 41 of the web 17a being cammed upwardly by the interfold plate 235 to open an angular relationship between the fold 41 and the fold 41a for the web 17a and form the trough 232. The lowermost fold 41a is drawn about a lower corner 240 joining the interleaving plate 235 to a horizontally disposed plate 242 disposed over the fold 41a and the remaining incoming webs 17b, 17c, etc. Thus, the troughs 232 and 233 are initially formed as seen in FIG. 15 and as the log 25 and webs move about an arcuate path to a tangent point, the fold 40 is brought into position vertically aligned with and beneath the fold 41 such as illustrated in FIG. 15a. At this position only the interfold plate 235 separates the folds 40 and 41 from being interfolded which they become as discharged from the ends 227a and 224a of the plates.

Referring now in greater detail to the illustrated interfolded plate 235, its upper inward edge 239 is arcuate and joined to the horizontally extending plate 215a to be positioned closely adjacent the annular surface 201 of the accumulator wheel. The interfold plate 235 extends downwardly at an inclination to the vertical to its lower and outer corner 240 which is secured to the horizontally extending plate 242, the latter being fastened at its inner arcuate edge to the top of a spacer block 243. The plate 242 is parallel to the stack support plate 215a and the web support 213a. Thus, it will be seen that the incoming series of webs 17a-17g travel in the space between overhead plate 242 and underlying web support 213a with the exception of the upper fold 41 which is on the top side of the interfold plate 235.

When interfolding incoming V-fold webs with a partially formed log of stacked V-fold webs on the flange support 212 of the wheel 28, the interfolding is achieved in generally the same manner described above for the Z-fold interleaving means 43 shown in FIGS. 14-16, only the dimensions being changed. As best seen in FIG. 17, an interfolding plate 235 opens a trough 233 and an angle between folds V1 and V2 for the lowermost web 17j of the partially formed log 25 moving into the tangent point 47 while similarly the opposite hand V-fold sheet is having its upper fold V2 opened up to forming the trough 232 with its lowermost fold V1. As the tangent point 47 is approached, the fold V1 of the incoming web 17a is brought closer to the fold V2 until they are superimposed, as described above, with the plate 235 separating them. As described hereinbefore, at the ends of the plates 213a and 215a the stack and incoming webs are discharged with the fold V2 of incoming web 17a inserted between the folds V1 and V2 of the web 17j of the stack of webs.

For the Z1 fold webs, the same general interfold means and shoes are used as described above except that the width dimension for the stack support plate 215 is increased from approximately a 3 1/2 inch width for the Z-fold webs to about 5 1/2 inches for the Z1-fold webs. Thus, a description of the interfold means and shoe for the Z1-fold webs would be redundant.

The inner edges 75 of the webs in the accumulating log 25 are bent with a smaller radius than the outer edges of the webs on the accumulator wheel. Even though the curvature is smooth and over a long radius, the webs in the log do tend to turn up from a flat planar condition when wound upon the accumulator wheel. Preferably, a stack confining and flattening means 244, as best seen in FIGS. 10c and 10b, is provided for exerting a holding force on the webs to keep them flat in the stack and in planes parallel to the flange support 212 and perpendicular to the annular surface 201. Herein, the stack flattening and confining means comprises a substantially annular belt-like ring 245 placed on the upper web 17a of the webs on the flange support 212. The ring 245 is split at slot 246 to allow the saw blade to cut the log without first removing the ring, as best seen in FIG. 10c.

The stack flattening ring 245 is free to rise as the stack of webs increases on the accumulator wheel and is carefully governed as to the force applied to the webs. To these ends, the ring 245 is carried on the outer free ends of long rods 247 pivotally mounted on the wheel trusses at pivot pins 247a. The radially extending rods 247 have belt fastening brackets 247b with downwardly extending legs 247c adjacent the annular surface 201 with outwardly bent legs 247d riveted to the ring. To control the force exerted on the webs by the ring, springs 248 urge the rods downwardly with a predetermined spring force and movable counterweights 249 are carried by the rod.

Because of the mass and inertia involved in a large accumulator 27, a drive means 251 for the accumulator 27 is of the rim drive kind for applying torque to the wheel rim 178 rather than a central drive means (not shown) applying a torque to the wheel hub 171. The illustrated rim drive means 251 comprises a pair of pneumatic drive wheels or tires 253, which are mounted on and rotated by vertically disposed axles 255, which engage the inner and outer sides of the driving flange 205 on the wheel rim. In this instance, the respective driving tires 253 are each carried on one end of the horizontally disposed support arms 257 which are pivotally mounted at their centers to turn about vertically disposed stub axles 259 carried by a support column 261 fixed to the floor.

The torque to turn the accumulator 27 may be selectively applied to and removed from the accumulator wheel by an operating means 262 which pivots the tire carrying arms 257 to swing the tires 253 into or from contact with the wheel rim 205. In this instance, the pivot arms 257 carrying the rotating wheels 253 are biased outwardly from driving relationship with the rim flange 205 by the biasing means 264 in the form of a strong compression spring which is fastened to the arms 257 forwardly of the pivot points 259 to push outwardly the tires from the rim flange 205 when the operating force from a fluid operating means 263 is released.

The compression spring 264 will be compressed from the position shown in FIG. 18 to that shown in FIG. 19 when a fluid cylinder 265 is operated to extend its ram 266 connected by a pin 267 to the outer pivot arm 257 while the cylinder body is connected by a similar pin 268 to the inner pivot arm 257. The operation of the fluid cylinder 265 thus swings the arms 257 to pinch the tires 253 against the rim flange 205 with sufficient force that there will be no slipping between the tires 253 and the accumulator wheel 28 so that the speed of the accumulator wheel is controlled by the speed of the tires 253. Of course, with removal of the pinching force from the hydraulic cylinder 265, the compressed spring 264 readily separates the wheels 253.

The acceleration and deceleration of the large mass of the accumulator 27 and its operational velocity are carefully controlled to form a smooth even aligned stack of webs on the log; and the accumulator velocity is preferably the base velocity to which the other web feed devices at the folding station 19 and the pull means 111 are subservient. Referring first to the drive of the accumulator wheel 28, only the inner tire 253 is driven. The outer tire serves a pinch member. The inner tire 253 has an axle 255 extending to a gear drive unit 271 (FIG. 20) fastened on a support 272 beneath the pivot arm 257 with an input shaft 273 to the gear unit extending horizontally to a floating gear couple 247. The latter is driven by a horizontally disposed floating shaft 275 extending to another floating gear coupling 276 driven by an output shaft 277 from a gear box unit 278 which is disposed beneath and aligned with a vertical axis through the stub shaft 259 supporting the inner tire carry arm 257. The right angle gear box 278 is driven by an input shaft from another gear box 279 which is driven by an input shaft 280 which has a gear coupling 282 with a long drive shaft 284 which extends to a main drive gear box 287. The main drive gear box 287 is connected by a shaft 288 on which is fastened a double sheave 291 driven by double belts 292 leading to double drive sheaves 293 mounted on an output shaft of a main drive motor 295. The main motor 295 is thus able through its belts 292 and shafts 288, 284, 280 and intermediate gear boxes to drive the worm gear drive unit 271 which drives the axle 255 and the inner tire 253. It is preferred that the motor 295 be speed controlled by a conventional electric motor controller (not shown) to accelerate gradually; and also to decelerate gradually the wheel 28 during the last several revolutions of the accumulator wheel prior to stopping the wheel rotation.

In the illustrated rim drive means the outer tire 253 is not driven but is merely an idler backup. To stop rotation or brake the outer drive tire 253, the latter is provided with an air disk brake means 297 which includes a caliper disk brake 298 having a brake disk 299 fastened to the lower end of the outer tire axle 255. Thus, the outer tire may be quickly brought to a stop with operation of the air disk brake 297 after the air cylinder 265 is operated to allow the compression spring 264 to separate the tires 253 from the wheel rim flange 205.

As stated previously, formation of smooth unwrinkled folds and neat stacks of folded webs on the accumulator 27 is achieved by careful control of the web tension and web velocity through each of the various portions of the folding station 19, the pull section 111 and onto the accumulator wheel 28 itself. The transport of the webs through the sets of folding shoes and through the pull section and onto the accumulator wheel is carefully controlled as to time and speed by means of an integrated drive means which in this illustrated embodiment of the invention uses a common motor 295 (FIG. 19) for driving the accumulator wheel 28, the pull means 111 and the feed rolls 73 at the slitter station 65, and the unwind belts 65 for the parent rolls 51 of paper stock. By means of a common drive, the web feed in each station is kept in synchronism during the initial acceleration of the accumulating wheel 28, at the nominal operation speed and during deceleration of the accumulator wheel 28.

The paper stock is a flexible, stretchable, and contractable material which stretches with friction and resistance to movement particularly at the folding shoes and to compensate for stretching and changes in tension; the speed of operation of pull means 111 may be adjusted relative to the speed of the accumulator wheel 28 and also relative to the speed of the paper drives through the folding station 19. Moreover, such adjustments are particularly desirable when using different sets of folding shoes and to adjust for variations in ambient temperature, humidity or when changing paper sotck or parent rolls.

Referring now more specifically to FIGS. 19 and 8, the motor 295 drives its double belts 292 to turn the double sheaves 291 and shaft 290 which is connected through an electromagnetic clutch 301 to a drive means 302 extending to the pull section 111 and to the folding station 19. On the output side of the clutch 301 is a drive shaft 304 which extends to a right angle gear unit 303. The output side of the right angle gear unit 303 drives a horizontally extending shaft 305 extending to a gear box 307 which has a right angle takeoff 309 driving a variable speed device 310 which, in turn, drives the pull belts 115 and 117 of the pull means 111. In this instance, variable speed device 310 comprises a first variable pitch sheave 312 mounted on an output shaft from the gear box 307 and it drives a short belt 311 entrained about a sheave 313. By suitable adjustment of a hand wheel 315 on the sheave 312, the nominal pitch diameter of the sheave 312 may be adjusted and thereby vary the output rotational velocity of shaft 317 carrying the sheave 313. The output shaft 317 is connected to another gear unit 318 which has a take off for rotating the axle 157 (FIG. 8) to turn the pull belts 115 and 117 of the pull means 111. While the pull means is operating, the operator may turn the handwheel 315 to increase the speed of the pull belts 115 and 117 slightly relative to the web travel speed of the stacked webs on the accumulator to decrease tension in the incoming webs or alternatively the speed of the pull belts may be decreased from the speed of the webs on the wheel 28 to increase the tension in the webs as they travel through interfolding means 43 and onto the accumulator wheel 28.

The drive from the gear box 318 also is extended to the folding station by means of an output shaft 321 extending through several gear boxes 322 to a right angled gear box 323 having an output shaft 324 leading to a right angle gear box 325 having an upwardly extending jack shaft 326 which serves as an input drive for the web feed rolls at the slitter station and the belt unwinders for the parent rolls. The gear box 322 has an output shaft 327 which serves as a drive for the lay down conveyor 74.

To allow the draw and tension control of the webs being folded, an adjustable variable pitch device is provided for the feed rolls 63 and unwind belts 65 and also for the slitter drives. More specifically, the incoming jack shaft 326, as best seen in FIG. 23, drives a right angle gear unit 328 having a horizontally disposed output shaft 329 leading to a gear drive 330 having a transversely extending output shaft for driving a pair of variable pitch sheaves 331 and 332 fastened on opposite ends of the output shaft. The variable pitch sheave 332 drives a belt 333 and a sheave 335 on a shaft 336 which extends laterally to a belt drive 337 for driving a slitter shaft 339. The other variable pitched sheave 331 drives a belt 341 entrained about a sheave 343 mounted on a shaft 345 for driving a right angle gear unit 347 having a downwardly extending jack shaft 349 which is interconnected through suitable drive belts to the unwind belts for the parent rolls. Thus, it will be seen by adjusting the variable pitched sheave 331 the speed of the unwind from the parent rolls may be adjusted slightly from the nominal linear speed to assure that there are no wrinkles and that the proper draw tension is achieved between the unwind and the slitter devices. Also by adjusting the tension of the slitter drive by turning the variable pitch sheave 332, the draw and tension through the folding shoes and onto the lay down conveyor may be adjusted. The details of drive of the unwind belts 57 and the slitter devices is disclosed in the aforementioned application; and hence is not repeated herein.

As best seen in FIG. 19, the main drive motor 295 may be selectively coupled by operation of an electromagnetic clutch 335 to a right angled gear box 337 to provide drives for a compressor conveyor 333, and a banding means at the banding station 32. More specifically, with operation of the clutch 335, the motor 295 will turn drive shaft 339 and through a right angled gear unit 337 turns a shaft 338 connected to a variable speed takeoff means 340 which has its output connected to a compressor conveyor 333.

The variable speed takeoff means 340 is similar to the device 310 for the pull means 111 and hence will not be described in detail. Briefly, the variable speed means 340 is driven by a right angle takeoff 342 from the shaft 338 and includes an adjustable pitch diameter sheave 341 to control the rotational velocity of its output shaft which is supported by means 343 and extends to a drive for the compressor conveyor 333. The shaft 338 also extends to a similar speed reducing device 344 associated with the banding means 32. Thus, the tension in the log 25 may be controlled between the compressor conveyor and the bander conveyor, as will be explained in greater detail.

Prior to removal of the log 25 from the accumulator 27, it is first cut by a cutting means 29 which oscillates a rotating cutting blade 351, as best seen in FIGS. 1 and 24, through a slot 353 formed in the flange support 212 and rim 178 of the accumulator wheel 28 to form a split log of generally circular configuration thereby providing a free end for feeding into the nip of a compressing conveyor 333. To assure that the slot 353 in the accumulator wheel 28 is aligned with the saw blade 351, when the latter is oscillated toward the wheel and the log 25 thereon, a locating means 354 is provided which interlocks with or detents with a portion of the wheel when the slot 353 is vertically coplanar with the saw blade.

The illustrated locating 354 means includes a detent 355 carried on a detent lever 357 for insertion into and opening 359 in the rim flange 205 of the wheel 28. When the detent 355 is inserted in the notch 359, as illustrated in dotted lines in FIG. 23a, the wheel is properly located and held against turning; and lever arm 357 will actuate a switch means 359 which is in the control circuit for the means to oscillate the saw blade 351. Only when the switch means 359 is operated, may the saw blade be pivoted toward the log 25. During the terminal portion of the accumulation of the log of webs, the accumulator wheel is slowly driven and the detent slides along the driving flange until its detent 355 slides into the notch 359. The detent lever 357 is moved toward or from the wheel by an operating means in the form of an air cylinder 361 carried on a stand 363. The air cylinder 361 has an actuating rod 365 pinned to a crank arm 367 fastened to a lower end of a vertical operating shaft 369 connected at its upper end of the lever arm 357 for the detent 355. After sawing the log, the cylinder rod 365 is extended to swing the lever arm 357 to the solid line position shown in FIG. 23a and the cut log 25 is ready for removal from the accumulating wheel.

The cutting blade 351 mounted on a support shaft 369 disposed horizontally and spanning a pair of oscillating arms 370 mounted in a frame 371 for pivotal movement toward or from the accumulator 27. As best seen in FIG. 24, the cutting blade 351 is rotated by a belt drive including an upper sheave 373 fixed to the shaft 369 about which is entrained a drive belt 375 extending downwardly to a lower sheave 377 attached to and driven by a shaft 378 which in turn is driven by an attached sheave 379. The latter sheave is driven by a belt 380 extending to a sheave 381 fastened to an output shaft of a saw drive motor 382.

The motor 382 also serves to oscillate the arms 370, which are pivotally mounted axles coaxial with the shaft 378, by means 383 now to be described. More specifically, the motor 382 is operative through a one revolution clutch 385 to turn eccentrics 387 each mounted in a wrist 388 carried by horizontally extending arms 389. The latter extend horizontally from the eccentrics and are connected by pivot pins 384 to the oscillatable arms 370. As the lower ends of the oscillating arms 370 are coaxial with the shaft 378 the saw turning belt 375 will remain at the same length during the oscillation of the arms.

The oscillation of the arms occurs as follows: with operation of one revolution clutch 385, the saw motor 382 transmits its drive through its belt 380 to another sheave 390 on the support shaft 378 to turn a belt 391 and another sheave 392 on the shaft 393 carried by a portion of the frame means 371. Another sheave 395 is secured to the shaft 393 and drives a belt 396 extending to a sheave 397 secured to the input shaft 398 for the one revolution clutch 385. The output side of the one revolution clutch 385 drives a chain 399 extending upwardly to a sprocket 400 which is on a common shaft (not shown) with eccentrics 387 which are turned by this shaft while in the wrists 388 through 360.degree. during which turning the saw support arms 370 are oscillated.

More specifically, during the first 180.degree. of turning the eccentrics 387, the saw blade 351 is moved into and through the log which is at its maximum only 5 1/2 inches in width so that the throw of eccentric need not be very large. On the latter 180.degree. of turning of the eccentrics, the arms 370 are returned to the position illustrated in FIG. 24 with the one revolution clutch disengaging. An electrical control circuit (not shown) for the one revolution clutch 385 includes a detent operated switch means 359 which, when detent 355 is engaged in the notch 359, enables a circuit to be completed to operate the one revolution clutch 385.

After cutting the leg 25, one end thereof is turned while on the accumulator wheel 28 to a position adjacent a lower conveying belt 401 of the compressor conveyor 333. The leading end of the log 25 is fed into a nip formed by the generally horizontally extending lower conveying belt 401 and a downwardly inclined portion 402 of an upper compressor belt 403 disposed thereabove to engage and exert a forward driving force on the log 25. The upper belt 403 extends from a forward drive roll 404 downwardly across an inclined dead plate 405 to idler change of direction roller 407 at which location the log 25 will be compressed to the maximum extent desired prior to banding. The upper belt continues along a generally horizontal path parallel to the forward run of the lower belt 401 to a discharge roll 409 at which the upper belt 403 returns past a pair of tension rolls 410 to return to the drive roll 404. The lower belt 401 extends from an inlet roll 411 to an outlet drive roll 412 and is tensioned by an intermediate roll 413.

The compressed height desired for the leg 25 depends on the number of variations such as the type of folded sheet, the count of sheets in the log and the bulk desired for the sheets when banded. To accommodate these varying requirements, the upper compressing belt 403 (FIG. 25) and the force it exerts on the leg 25 may be varied by shifting vertically the upper belt 403 and its upper frame 419. This allows varying the height of the log issuing at the discharge end of the compressor conveyor 333. Preferably, this vertical shifting is accomplished without having to readjust the drive for the belts 401 and 403. The banding means also has a similar adjustable upper conveying belt 417 as best seen in FIG. 26. Therefore, the manner of adjusting and driving these upper belts will be identified by common numerals in both FIGS. 25 and 26. More specifically, the upper belt is carried on a vertically movable horizontal frame 419 mounted between forward and rear pairs of upstanding columns 421 and constrained by slides 423 sliding in guideways to assure a generally parallel vertical movement of the fore and aft ends of the frame means 419. In this instance, the slides 423 are fastened to the upper sides of the conveyor frame 419 and each carries a lower end of a vertically extending screw 425 which is threaded in a nut carried in an overhead cross beam 427 between the columns 421. Fastened to the screws 425 are sprockets 429 which will rotate the screws 425 in the nuts to cause frame means 419 and the slides 423 to slide vertically along guideways in the support columns 421. Each of the sprockets 429 is driven by a chain 431 which extends horizontally to a pair of internal drive sprockets 433, FIG. 25, driven by a direction changing sprocket and chain arrangement 435 which in turn, is driven by a shaft 437 on which is a manually rotatable hand wheel 439. By turning the hand wheel 439 and shaft 437, the change of direction arrangemnt 435 is operated to turn the respective sprockets 433 in opposite directions and drive the chains 431 to turn the sprockets 429 and thereby the screws 425 to raise or lower simultaneously and at equal rates the fore and aft ends of the frame means 419.

The preferred manner of driving the upper conveyor belt 403 for the compressor conveyor shown in FIG. 25 automatically adjusts irrespective of any vertical repositioning of the frame means 419. This drive means is shown only in FIG. 25 and a description thereof will suffice for an understanding of how the upper conveyor 417 for the banding means shown in FIG. 26 is also driven. More specifically, the drive roll 404 for the upper conveyor belt is driven by its supporting shaft 441 which carries a sheave 443 about which is entrained the drive belt 445. The drive belt 445 has a vertical run parallel to the adjacent column 421 and is wrapped about the sheave 443 by a pair of guide rollers 446 and 447. The guide rollers 446 and 447 are mounted in the frame means 419 with their supporting axles 449 disposed horizontally and parallel to the axle 441 which is mounted the sheave 443. Thus, it will be seen that the frame means 419 may be shifted vertically without the length of the drive belt 445 having to be changed between an upper idler sheave 450 journaled on an axle 451 on a bracket 453 secured to the column 421 and a lower input sheave 455 mounted on a shaft 457 on the lower stationary frame means 456. The shaft 457 is driven by an input sprocket 459 from a chain 460 extending to a sprocket 461 driven by a shaft 462 extending to the adjustable pitch diameter speed controlled means 340 shown in FIG 19.

At the banding station 30, the compressed log 25 is received from the compressing conveyor 333 and is automatically banded while traveling between upper endless conveyor belt 417 and a lower conveyor belt 465. The banding or wrapping of the log 25 may be made in various manners but in the illustrated embodiment of the invention the band 31 is made in a continuous manner from two elongated banding webs 467 and 469 which are formed into elongated channel shaped webs by folding means comprising folding shoes 471 and 473. More specifically, the lower banding web 469 is formed into a channel shape with a flat central portion 469a for abutting against a bottom side of the log 25 with upwardly extending margins 469b engaging the vertical sides of the lower portion of the log 25. In a similar manner, the folding shoe 471 forms a generally central flat top portion 467a to engage the top of the log 25 and a pair of downwardly extending portions 467b are turned downwardly along the vertical sides of the log 25 to overlap and be external of upper marginal edges 469c of the lower web 469.

The folding shoes 471 and 473 are generally similar in operation; and, as best seen in FIGS. 27 and 28 comprise a generally inclined trapezoidal shaped plate 475 having side edges 477 across which the web is drawn toward a small central edge 480 which is parallel to a forward edge 479 for the plate 475. A rotatably roller 481 is mounted to turn about a horizontal axis adjacent edge 479 of the plate 479 to assist in drawing the web about the inclined edges 477 of the plate 475. At the edge 480, the outer margins of the web 469 are drawn along inclined edges 483 of a pair of triangular plates 485. The triangular plates 485 are bent to project generally at right angles from a central horizontal portion 482 therebetween, the triangular shaped plates 485 for the upper folding shoe 473 being bent outwardly from a right angular relationship, as best seen in FIG. 28. The triangular shaped plates 485 are disposed vertically and complete the forming of upwardly extending sides 469b for the now channel shaped web which then moves against the log 25 and belt 465 which pulls the same through the banding apparatus.

The longitudinally extending overlapped marginal edges 467b and 469b of the respective banding webs 467 and 469 may be joined in a number of manners such as by having preformed pressure adhesives thereon, by applying an adhesive to one of the facing edges or by applying a hot-melt adhesive. Herein, applicator nozzle means 487 on opposite sides of the log apply thin beads of hot-melt adhesive along the outwardly facing side of the web portions 469b for contact with the incoming downwardly extending web portions 467b of the upper web 467. A series of pressure rollers 489 downstream of the applicator nozzles means 487 may press the marginal edges of the webs against each other to assure adhesion thereof to form a continuous enveloping band 31 about the log 25 at the same speed as the log moves through the banding station. Thus, it will be seen that the log 25 may be readily banded prior to severing into the individual stacks, 13a, 13b, 13c or 13d of sheets.

After banding the leg 25, the operator will cause the clutch 335 (FIG. 19) to open and disconnect the motor drive from the motor 295 to the banding station's conveying belts 417 and 465; and begin formation of another log 25. The banded log discharged from the banding station is laid on an intermittently movable log conveyor 486, as best seen in FIG. 19, which is sufficiently long, 100 feet in this instance, to hold the log for severing by the severing means 33 at the severing station. The log 25 is moved intermittently by the log conveyor 486 by its drive motor 488 which operates an overrunning one way clutch 490 connected to the conveyor 486. The clutch 490 is a conventional clutch of a kind which is described in more detail hereinafter in connected with the banding station.

The severing means 33 for severing the log at the severing station 30 preferably has the ability to change the length of the severed log portion or stack severed from the long log 25. Also, the illustrated severing means 33 will accommodate various heights of banded logs 25 due to the various kinds of folds and the counts of webs in the various logs formed. As will be explained in connection with FIG. 29, the incoming log is tensioned and taut at the area being cut to provide a cleaner and better cutting operation.

To these ends, the illustrated severing means 33 comprises a set of input pull belts 491 and 493 which are driven at a slightly slower speed than a pair of output conveyor belts 495 and 497 which discharge the cut stacks of fold sheets. This difference in speed is provided by having driven sprockets 499 for driving the output driven drums 500 for the output belts 495 and 497 of a smaller size than the drive sprockets 501 for the drive drums 503 for the input conveyor belts 491 and 493. The respective sets of upper and lower sprockets 499 and 501 are joined by chains 505 on the side of the apparatus opposite the path of the rotating saw blade 506 so as not to interfere with cutting of the log 25 held between the infeed and outfeed conveying belts. As the output conveying belts 495 and 497 are driven at a faster speed they exert tension on the log 25. When the cutting is completed, the output belts 495 and 497 accelerate the stack to space it from the slower moving new leading end of the log moved forwardly by the infeed belts 491 and 493.

Each of the upper conveyor belts 493 and 495 is mounted on a vertically movable support frame means 509 carried on a vertically extending adjustable screw 511 which allows vertical shifting of the frames 509 relative to the supporting columns 512 in a manner described above in connection with the compressing and banding stations. Common reference characters have been applied to the hand wheel and chain drives for raising or lowering the frame 509 and the belts 493 and 495.

The upper conveyor belts 493 and 495 may be shifted vertically without changing belt tension as drive belt 513 for the upper conveyor belts has a first straight line run between sheaves 515 and 517 and second straight line run between guide rolls 522 and 523. These straight line runs merely change length with movement of the vertical position of the input belt frame means 529. The sheave 527 is fastened to a shaft 519 for driving a drive roller 521 to turn the upper infeed conveyor belt 493. The sheave 515 is journaled on an axle 520 carried on a bracket arm 524 fastened to the column 512. The change of direction sheave 522 is mounted on an axle on the upper frame means 509 and the lower roller 523 is journaled on an axle secured to a lower stationary frame member 526. The drive belt 513 receives its input drive from drive sheave 525 fastened to a shaft 527 for a lower drive drum 529 for the lower infeed conveyor belt 491. Each of the four conveyor belts is also provided with a tension roller 530 which may be shifted in a known manner to provide the desired tension in the respective conveyor belt associated therewith. The output conveyor belts 495 are provided with discharge rollers 532 about which the belts 495 and 497 being return movement to the left as viewed in FIG. 29.

In accordance with the illustrated embodiment of the invention, the leg 25 is moved intermittently with the saw blade 506 severing the log 25 while it is stationary. Also as mentioned hereinbefore, the preferred length of travel between saw cuts is readily adjusted to as to provide the desired length of sheet in each stack. To these ends the feed for driving the input shaft 527 for the conveyor belts 491, 493, 495 and 497 is through a motor drive means 535 which includes a one way clutch 534 (FIG. 30) connected to the drive axle 527 and having a variable throw crank means 539 for determining the amount of turning the axle 527 and feeding of the log 25 with each operation of the one way clutch 534.

More specifically, the motor drive means 535, as best seen in FIG. 31, comprises a motor 536 having an output shaft 540 driving a belt 541 entrained about a sheave 543 secured to a shaft 545 which in turn drives a double sheave 547 to turn a pair of belts 549 extending to a pair of double sheaves 551 on a shaft 553.

The shaft 553 is connected to the input side of a one revolution clutch 554, as best seen in FIG. 31, which has an output shaft 556 connected to a gear box 555. The gear box 555 has an output shaft 557 extending to a right angle gear box 558 which has an output shaft 559 for operating a variable throw mechanism 560 for the one way clutch 534 shown in FIG. 30.

The illustrated variable throw mechanism 560 controls the length of log movement between serving operations and comprises a circular disk 561 fixed to the shaft 559 to turn about a horizontal axis through the shaft 559. Formed in the disk 561 is an elongated radially extending slot 563 (FIG. 30). A slide 565 is mounted on the disk 561 and may be slid along the length of the slot 563 and locked in different radial locations thereon by tightening appropriate nuts (not shown). The slide 565 carries a driving pin 567 to which is fastened one end 569 of an adjustable link 571 extending to a pivot pin 573 carried by a crank arm 575 for the one way, over-running clutch 534. In this instance, the clutch 534 has ratchet teeth thereon, not shown, and the crank 575 carries a pawl (not shown) which is operative when turned in the counterclockwise direction by a pulling force from the link 571 to turn the shaft 527 and thereby drive the conveying belts at the severing stations. The link 571 is operative through a maximum of 180.degree. of movement of the disk 561. The pawl merely slides past the ratchet teeth of the clutch 534 without turning the same when in the over-running portion of its revolution. This is a conventional one way, over-running clutch 534. By adjusting the radial position of the slider 565 the amount of effective displacement of the link 571 and degree of rotation of axle 527 for each revolution of the disk 561 can be varied. This in turn, varies the length of the stack cut from the log 25.

The severing blade 506 for cutting the stacks from the log 25 is secured to a horizontally extending shaft 579, as best seen in FIG. 30, journaled for rotation in bearings on the upper ends of pivotally mounted, saw carrying arms 581. The lower ends of the arms 581 are pivotally mounted by bearings on stub shafts 583 to pivot about an axis through these shafts 583 which is coaxial with the shaft 545 carrying a drive sheave 587 for turning a belt 589 to rotate an upper sheave 591 fastened to the saw blade carrying shaft 579. Thus, the belt 589 will not be extended as the saw blade is oscillated by the arms 581 toward and from the leg 25. Preferably, the saw blade is continually rotated by the motor 536 which through the drive belt 541 and sheave 543 continuously turns the shaft 545 carrying the sheave 587 for turning the saw blade 506.

To oscillate the saw blade 506 to cut log 25 the arms 581 are oscillated by a crank means 591 (FIG. 32). More specifically, the latter comprises rotatable crank arms 593 pinned to laterally extending connecting rods 595 pinned at first ends to the crank arms 593 and pinned at the other ends thereof to the oscillatable arms 581. As the crank arms 593 rotate through 360.degree. with a turning of a common supporting shaft 597, the saw blade 506 is swung about the stub axles 583 toward and from the log 25. The shaft 597 is disposed horizontally and journaled in the upper ends of a pair of upstanding posts 599. The shaft 597 is rotated through one revolution by a chain drive including a sprocket 600 secured thereto and a chain 601 extending downwardly to a sprocket 603 mounted on the shaft 577 (FIG. 31). The shaft 577 is driven by the gear reducer 555 when the clutch 554 has been operated.

The timing of the saw blade oscillation is such that the saw blade 506 moves into the log 25 and returns from the log during the non-driving portion of the cycle of the clutch 534. That is, during the at least 180.degree. movement in which the clutch pawl is simply sliding by the ratchet teeth, the saw blade 506 moves into the log to sever the same and then retracts from the log. Thus, it will be seen that a common drive may be provided for synchronizing the log transport and the severing of the log while it is stationary.

The log conveyor 486 (FIG. 19) initially carries the bulk of the log with only a short forward portion thereof being gripped by the input pull belts 491 and 493; and the motor 488 for the log conveyor is slaved to the severing station's motor 536. The log conveyor clutch 490 is similar to the over-running clutch 534 with the result that the log conveyor 486 and the input conveyor belts are synchronized and travel through equal increments.

A brief description of the preferred method and operation of the illustrated apparatus will now be described in connection with forming and stacking Z-fold sheets. A parent roll 51 at the folding station is slit into seven webs 17a-17g each fourteen inches wide and folded by seven folding shoes 35a to form longitudinally extending Z-folds in each web. As disclosed in the aforesaid copending application, the Z-fold webs are interfolded with each other as they are carried by a lay down conveyor to a pull means 111.

The pull means 111 pulls the webs 17a-17g from the folding station 19 and the speed of the pull belts 115 and 117 determine the tension in the webs as they move into the interfolding means 43 and onto the accumulator wheel 28. Preferably, the tension in the webs is sensed by tension means 206 and is dept within predetermined limits by adjustment of an adjustable speed control device 310 of the integrated drive for the folding station and accumulator wheel. A speed adjustment of the pull means 111 automatically results in the same speed adjustment at the slitting station and at the parent roll unwind belts. The force exerted by the upper pull belt 115 is adjusted to control the compression of the series of webs 17a-17g and their bulk as they travel to the interfolding means 43.

At the beginning of the formation of a log, the leading end of the webs 17a-17g is threaded between the plates 213a and 215a and placed between the ring 245 and and flange support 212 of the accumulator wheel and secured thereto by a clip (not shown). The wheel 28 is rotated through almost 360.degree. to bring the leading end of the webs to the stack lifter 216a with the lowermost fold 40 of the lowermost web 17g threaded along the underside of interleaving plate 235. The upper fold 41 of the webs was threaded to travel along the upper side of the interleaving plate 235. Except for the fold 40 of lowermost web 17g of the stacked webs, the remaining leading web ends are placed over the support plate 215 and brought forward past the tangent point 47 and the interfolding means to be again placed beneath the ring 245 and clipped to the flange.

The accumulator wheel 28 is then accelerated to operational speed with the stacked webs on the accumulator being opened by the interleaving means and a fold of the incoming webs being opened and then interleaved with fold of the stacked webs with the incoming series of webs being inserted on the support flange beneath the opened stack of webs. The stack being formed is confined between the ring 245 and support flange 212 and gradually builds during each revolution of the wheel. After a predetermined number of revolutions, e.g. 25 revolutions, the clutch 301 is opened to stop drive to folding station 19, pull means 111 and the accumulator wheel 28.

With the detent 355 inserted into opening 359 in the wheel 28, the cutting blade 351 is pivoted to cut the log 25 with the blade traveling through a slot in the wheel. After the log is severed and the blade is retracted, the wheel 28 is turned to bring the leading end of the log to the compressor conveyor 333 with the log resting on the lower conveyor belt 401, as best seen in FIG. 25. The log is compressed between the upper and lower conveyor belts 401 and 403 to a predetermined height. The conveyor belts are driven by the integrated drive means with the clutch 335 operated and the clutch 301 opened. From the compressor conveyor 333, the log travels continuously forward through the banding station at which webs 467 and 469 are continuously formed into channel shaped configurations with their overlapped longitudinally extending edges adhered to each other to form a continuous band 31 about the log 25.

The banded log 25 is discharged to a log conveyor which holds the entire length of the banded log. Once the log is banded, the clutch 335 may be opened to stop further operations at the banding station and by the compressor conveyor 333 until the next log is formed.

The severing of the banded log 25 to form the individual banded stacks of Z-fold sheets is accomplished at the severing station 30 at which a saw blade 506 is oscillated to sever the banded log while it is stationary. The portion of the log being cut is pulled taut between input conveyor belts 491 and 493 which travel at a speed slower than the output conveyor belts 495 and 497. The latter separate the severed stack from the leading end of the log when the conveyor belts are next operated. The increment of feed of the conveyor belts between severing operations may be adjusted to control the length of the sheets in the stack. This is accomplished by varying the radial location of throw of a slider 565 on a disc 561 (FIG. 30) and thereby the displacement of a link 571 extending to and operating the over-running clutch 534 which drives the conveyor belts 491, 493, 495 and 497.

From the foregoing, it will be seen that webs may be folded longitudinally and form into a small stack or series of webs and then run continuously into an accumulating stack which is opened to receive the incoming webs and then closed during travel of the stack about a closed path. The incoming webs may be interfolded with each other and an interfolding means is provided to interfold a portion of one of the incoming webs with a portion of a web on the accumulator thereby forming a stack of interfolded webs throughout the height of the stack. By controlling the tension of the incoming webs and the tension of the webs being stacked on the accumulator, the webs may be stacked neatly and in a flat condition with their folds in place and without wrinkles therein. Preferably, the webs on the accumulator are confined between a lower support and an upwardly liftable retainer member placed on top of the stack.

While a preferred embodiment has been shown and described, it will be understood that there is no intent to limit the invention by such disclosure but, rather, it is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention as defined in the appended claims.

Claims

What is claimed is:

1. A method of producing individual stacks of folded sheets from a plurality of webs of stretchable sheet material, said method comprising the steps of:

continuously, longitudinally folding each of a series of webs of sheet material while the webs travel along a feed path, traveling the folded webs about a closed path about a vertical axis, lifting the traveling webs as they make a revolution about said closed path and traveling the incoming webs therebeneath, and accumulating a multiple series of the folded webs in a vertically stacked condition constituting an endless log at an accumulating station, and severing the endless log at predetermined and spaced locations to form a plurality of individual stacks of folded sheets. 9

2. A method in accordance with claim 1 including the further step of:

cutting the endless log while in a closed loop at the accumulating station, and feeding one end of the severed log forwardly from the accumulating station to a severing station and then severing the log into the individual stacks.

3. A method in accordance with claim 1 including the steps of drawing the series of web along a straight line feed path to the accumulating station and traveling the folded webs about a circular path which is tangential to said straight line feed path.

4. A method of producing individual stacks of folded sheets from a plurality of webs of stretchable sheet material, said method comprising the steps of:

continuously, longitudinally folding a series of webs of sheet material, superimposing the folded webs to form a series of folded webs and drawing the series of webs along a path tangential to and leading to an accumulating wheel rotatable about a fixed axis and having a circumferential supporting means for said webs, continuously winding webs with their edges in planes substantially perpendicular to said axis and at a substantially constant radius from said axis and continuously winding said stack of folded webs about said accumulating wheel for a plurality of revolutions of said accumulating wheel to form a circular log having multiple layers of said stacked folded webs thereon, cutting the circular log while on said accumulating wheel to form an elongated log, feeding one end of said log from said accumulating wheel toward a severing station along another path from said accumulating wheel, and severing said elongated log at spaced locations to form said individual stacks of folded sheets.

5. A method in accordance with claim 4 including the further steps of:

stopping said accumulating wheel prior to cutting said circular log,

straightening said elongated log from said circular configuration, and banding said straightened elongated log with a wrapper band prior to severing the banded log into the individual banded stacks of folded sheets.

6. A method in accordance with claim 4 including the further step of accumulating the stacks of folded webs vertically on the accumulating wheel and traveling the incoming series of webs beneath the webs already on the accumulating wheel.

7. A method in accordance with claim 6 including the further steps of:

compressing the elongated log and banding the compressed elongated log with a wrapper band prior to severing the banded log into individual banded stacks of folded sheets.

8. A method of producing individual stacks of interfolded sheets from a plurality of webs of flexible material comprising,

continuously, longitudinally folding a plurality of webs of sheet material, interfolding adjacent folds of adjacent webs to provide a series of interfolded webs traveling along a predetermined path to an accumulating station, accumulating said interfolded webs while traveling about a closed path at said accumulating station, interfolding at the accumulating station an outermost fold of the outer web of the series of interfolded incoming webs with an outermost fold of the outer one of the series of webs traveling about said closed path whereby the successive loops of webs are interfolded with one another to constitute a log of interfolded webs, and severing the log at spaced locations to form the individual stacks of interfolded sheets.

9. A method of accumulating a circular log of folded webs from a stack of incoming folded webs of stretchable sheet material, said method comprising the steps of: feeding said stack of incoming webs along substantially linear path to a tangential intersection with an accumulator rotatable about a vertical axis, bending said incoming series of webs about said accumulator sheel to form a circular stack with the inner edges of said webs aligned at a substantial constant radius from said vertical axis and with the webs in substantially horizontal planes, shifting vertically the circular stack of webs on the accumulator adjacent said tangent point and joining the incoming stack of webs with the vertically shifted circular stack of webs on the accumulator.

10. A method in accordance with claim 9 including the further step of confining the webs in the circular stack between overlying and underlying surfaces to hold the webs in flat horizontal positions while bent and accumulated into said circular stack.

11. A method of accumulating a circular stack of webs from an incoming linear stack of webs, said method comprising the steps of:

continuously traveling said linear stack of webs along a substantially linear path to an accumulating station having a circular accumulator rotatable about a vertical axis to intersect the linear path at a tangent point, bending the linear incoming stack of webs about an annular surface on said accumulator and into a circular stack, raising the circular stack of webs from a horizontally disposed annular support on said accumulator at a position adjacent said tangential intersection, inserting continuously said incoming linear stack of webs beneath the lifted circular stack of webs, applying a force to the top of the circular stack to maintain webs in flat horizontal positions, and controlling the tension in webs to within predetermined limits to avoid loose or overly taut webs.

12. A method in accordance with claim 11 in which said all of webs in said circular stack are interfolded said method comprising the further steps of: interfolding each of the webs of said linear stack, opening a fold in the outermost web of said linear stack adjacent said tangential intersection, opening a fold on a lowermost web of the circular stack of webs on said accumulator, and interleaving the opened folds of said respective webs adjacent said tangential intersection.

13. A method of producing individual stacks of folded sheets from a plurality of webs of stretchable sheet material, said method comprising the steps of:

continuously, longitudinally folding each of a series of webs of sheet material while the webs travel along a feed path, interfolding portions of each of the series of webs into interfolded relationship and subsequently traveling the interfolded webs about a closed path, traveling the folded webs about a closed path a plurality of times, accumulating a multiple series of the folded webs in a vertically stacked condition constituting an endless log at an accumulating station, continuously interfolding an edge portion of an outer web of the stacked webs finishing a lap about said closed path with an edge portion of an outer web of the series of interfolded webs incoming into the closed path to provide a stack of webs interfolded throughout its height, and severing the endless log at predetermined and spaced locations to form a plurality of individual stacks of folded sheets.

14. A method of producing individual stacks of folded sheets from a plurality of webs of stretchable sheet material, said method comprising the steps of:

continuously, longitudinally folding a series of webs of sheet material, superimposing the folded webs to form a series of folded webs and drawing the series of webs along a path tangential to and leading to an accumulating wheel, interfolding a portion of each web of the series of webs prior to being accumulated, continuously winding said stack of folded webs about said accumulating wheel for a plurality of revolutions of said accumulating wheel to form a circular log having multiple layers of said stacked folded webs thereon, continuously interfolding the outermost portion of an outermost web of an incoming series of interfolded webs with a portion of an outermost web of the circular log being formed on the accumulator wheel so that all of the webs on the accumulator wheel are in interfolded relationship throughout the log, cutting the circular log while on said accumulating wheel to form an elongated log, feeding one end of said log from said accumulating wheel toward a severing station along another path from said accumulating wheel, and severing said elongated log at spaced locations to form said individual stacks of folded sheets.

15. A method of accumulating a circular log of folded webs from a stack of incoming stretchable sheet material, said method comprising the steps of: means at said folding station for interfolding portions of said series of webs into interfolded relationship with each other, feeding said stack of incoming webs along a substantially linear path to a tangential intersection with an accumulator rotatable about a vertical axis, means at said accumulating station for interfolding an outer portion of one of the webs of the incoming series of webs into interfolded relationship with a portion of the series of webs finishing a lap about said closed path whereby all of the webs in the log on the accumulating means are interfolded with each other bending said incoming series of webs about said accumulator wheel to form a circular stack, shifting vertically the circular stack of webs on the accumulator adjacent said tangent point and joining the incoming stack of webs with the vertically shifted circular stack of webs on the accumulator.

16. An apparatus for producing individual stacks of folded sheets from a plurality of webs of stretchable sheet material, said apparatus comprising folding means at a folding station for folding each of a series of webs of sheet material with at least one longitudinally extending fold while the webs travel along a feed path, an accumulating means for receiving said series of folded webs and for carrying the webs about a closed path about a fixed axis for a plurality of times, support means on said accumulating means for supporting said webs with inner edges thereof aligned at a predetermined distance from said axis and with said folded webs being stacked in planes substantially perpendicular to said axis and to accumulate said folded webs in a stacked condition constituting an endless log at an accumulating station, means for displacing the accumulating folded webs on said support means and for guiding the incoming webs on to said support means, and means for severing the endless log at predetermined and spaced locations to form a plurality of individual stacks of folded sheets.

17. An apparatus in accordance with claim 16 in which a cutting means severs the endless log while on said accumulating means and in which a conveying means carries said log from said accumulating station to said severing means.

18. An apparatus in accordance with claim 17 in which said accumulating means comprises a rotatable wheel having a circular closed path for accumulating a circular log of folded webs thereon, said circular closed path being tangential to the feed path of said series of webs from said folding means.

19. An apparatus in accordance with claim 16 in which a banding means is provided for banding said log with a band to hold said folded sheets in a stacked condition and in which said severing means severs said banded sheets subsequent to banding so that the stacks are already banded when severed from said log.

20. An apparatus for producing individual stacks of interfolded sheets from a plurality of webs of sheet material, said apparatus comprising means at a folding station for forming continuous, longitudinally extending folds in each of a series of webs of sheet material, means for closing the portions of adjacent folds of adjacent webs into interfolded relationship while traveling along a predetermined path to an accumulating station, an accumulating means at said accumulating station for carrying said interfolded webs about a closed path for a series of cycles for stacking the incoming series of webs into an endless log, means interfolding a fold portion of one of the incoming series of webs from the folding station with a fold portion of one of the webs completing a cycle about said closed path to cause the webs on the accumulator to be interfolded with each other throughout the height of the stacked condition, and means for severing the log at spaced location to form individual stacks of interfolded sheets.

21. An apparatus in accordance with claim 20 in which said means for interfolding one of the incoming series of webs with the webs making a cycle on the accumulating means comprises an interfolding shoe for forming troughs in said webs for inserting a longitudinally extending portion of a web on the accumulating means into a portion of the incoming web of the series of webs.

22. An apparatus in accordance with claim 21 in which said interfolding shoe lifts the stack of webs on the accumulating means while forming the troughs to interfold the webs together.

23. An apparatus in accordance with claim 20 in which means are provided for sensing the tension in the webs traveling along said predetermined path to said accumulating station, and means are provided for varying travel speed of said incoming webs relative to the travel speed of said webs traveling about said closed path to cause the tension in said webs to be within predetermined limits of tension.

24. An apparatus in accordance with claim 20 in which said accumulator comprises a wheel rotatable about a vertical axis, a support on said accumulator wheels supports the webs in a circular stacked condition on said wheel, and means on said accumulator confines and flattens the webs being stacked on said support.

25. An apparatus for producing individual stacks of folded sheets from a plurality of webs of flexible sheet material, said apparatus comprising: folding means at a folding station for folding each of a linear stack of webs of sheets material with at least one longitudinally extending fold while the webs travel along a substantially linear feed path, means for feeding said sheets along said feed path to an accumulating station, an accumulating wheel at said accumulating station rotatable about a vertical axis for receiving said series of folded webs and for carrying the webs in a circular path for a plurality of times to accumulate the incoming webs in a circular stack constituting an endless log, means adjacent a juncture of said feed path and said circular path to shift vertically the circular stack of webs on the accumulator wheel relative the plane of linear stack of webs to allow joining of the incoming webs with the circular stacked webs, means for confining the circular stack of webs and for holding the same in flat horizontal positions on said accumulator wheel, means for adjusting the speed of travel of said linear stack of webs relative to the speed of web travel on said accumulator wheel to maintain tension in the webs within predetermined limits of tension, and means for severing the endless log at predetermined and spaced locations to form a plurality of individual stacks of folded sheets.

26. Apparatus in accordance with claim 25 in which said stack separating means comprises a surface for lifting the bottom of the stack on the accumulating wheel and a surface for supporting and guiding said incoming webs to a tangent point for insertion beneath the lifted circular stack of webs.

27. An apparatus in accordance with claim 26 in which said confining and flattening means for said stack comprises an overlying ring means resting on the top of the circular stacked webs on the accumulator wheel for holding the webs in a substantially horizontal flat condition while being accumulated.

28. An apparatus in accordance with claim 26 in which said stack separating means further comprises an interfolding shoe for opening a fold in the lowermost web of the circular stack of webs and for opening an upper fold on the incoming linear stack of webs, said interfolding shoe guiding said open folds into superimposed relationship for interleaving upon discharge from said stack separating means.

29. In an accumulator for interfolding a fold of an incoming linear stack of webs traveling along a linear path with a circular stack of webs traveling through said interfolding shoe, a shoe means comprising a first support surface for said linear stack of webs, a camming surface for lifting the circular stack of webs on an accumulator, a second support surface for receiving said lifted stack and for guiding the same to adjacent a tangent point between the circular path and the intersecting linear path, a first interleaving surface for opening a trough within the folds in the lowermost web of the lifted webs, a second interleaving surface for forming a trough within the folds of the upper web of the incoming stack of webs, a supporting surface for supporting the incoming stack of webs for travel along a linear path to the tangent point, said first and second interleaving surfaces extending toward said tangent point for guiding said opened folds into superimposed relationship so that upon discharge from said interfolding shoe means and the closing of said folds and the closing of the troughs the webs are all interfolded.

30. An accumulator in accordance with claim 29 in which an inclined plate extends between said first and second supporting surfaces, said first interleaving surface comprising the underside of said inclined plate, and said second interleaving surface comprising the upper side of said inclined plate.

31. An accumulator in accordance with claim 29 in which a lower horizontal extending plate has its upper surface constituting said first supporting surface, an upper plate is disposed parallel to said lower plate and spaced therefrom with said incline plate being intermediate said upper and lower plates, said upper surface of said upper plate constituting said second supporting surface and said camming surface comprises the upper surface of a downwardly inclined plate projecting from said upper plate.

32. An apparatus for producing individual stacks of folded sheets from a plurality of webs of stretchable sheet material, said apparatus comprising folding means at a folding station for folding each of a series of webs of sheet material with at least one longitudinally extending fold while the webs travel along a feed path, means at said folding station for interfolding portions of said series of webs into interfolded relationship with each other, an accumulating means for receiving said incoming series of folded webs and for carrying the webs about a closed path for a plurality of times to accumulate said folded webs in a stacked condition constituting an endless log at an accumulating station, means at said accumulating station for interfolding an outer portion of one of the outer webs of the incoming series of webs into interfolded relationship with a portion of the series of webs finishing a lap about said closed path whereby all of the webs in the log on the accumulating means are interfolded with each other and means for severing the endless log at predetermined and spaced locations to form a plurality of individual stacks of folded sheets.