US 3333523 A
Description (OCR text may contain errors)
Aug. 1, 1967 D. TERZUQU 3,333,523
BAGS AND METHOD AND APPARATUS FOR PRODUCING THE SAME;
Filed Dec. 20, 3.965 2 Sheets-Sheet l ATTOQNEV Aug. l, 1967 D.' Tmzucm BAGS AND METHOD AND APPARATUS FOR PRODUGING THE SAME 2 Sheets-Sheet 2 Filed Dec. 2O 1965 nomma# renzuou ATTQLRNEY United States Patent O 3,333,523 BAGS AND METHOD AND APPARATUS FOR PRODUCING THE SAME Dominick Terzuoli, 2258 E. 70th St., Brooklyn, N.Y. 11234 Filed Dec. 20, 1965, Ser. No. 515,094 9 Claims. (Cl. 93-8) This invention relates generally to bags, such as, for example, disposable lter bags for vacuum cleaners, and to a method and apparatus for producing such bags.
Disposable filter bags for vacuum cleaners are generally formed of paper or other fibrous flexible material which is porous. Such bags usually are closed at one or both ends and have opposing panels which are connected at the sides of the bag by a plurality of pleats or gussets to permit expansion of the bag. Further, an apert-ure is provided either at an end of the bag or in one of the panels thereof for cooperation with the air inlet opening of the vacuum cleaner casing. Since bags of the described character are intended to be disposable, great emphasis is placed on the low cost production thereof. Low cost production of the bags obviously requires economical utilization of the fibrous liexible material forming the bags, high speed operation of any machines that may be employed for the bag production, and minimization of any manual labor.
In the production of bags of the described character, the fibrous exible material is usually supplied in the form of a continuous web, for example, unwound from a roll thereof, and is moved continuously along a predetermined path. During such movement of the web, adhesive is applied along a longitudinal edge of the web and thereafter the web is folded longitudinally upon itself so as to overlap and secure together the longitudinal edge portions of the web by means of the previously applied adhesive, thereby to form a tube. The folding operations further provide the tube with opposed panels connected, at the sides, by a plurality of pleats extending longitudinally along thetube. The pleated tube formed in the foregoing manner is transversely cut at locations spaced therealong to provide separate tube sections intended to form respective bags.
In forming a bag from each tube section, it is necessary to close at least one of the ends of the tube section. One existing method of' closing an end of the tube section involves applying a stripe of adhesive across an end portion of the tube section which is thereafter folded over. In order to ensure that both panels of the folded over end portion of the tube section will be adhesively secured, this method of closing a bag end requires that the opposed panels of the pleated tube be cut along offset lines when dividing the tube into tube sections. Although devices exist for effecting such cutting of the pleated tube during its continuous movement in the longitudinal direction, such cutting devices have a limited practical operating speed, as do the devices provided for folding over an end portion of each tube section after adhesive has fbeen applied thereto, so that the rate at which the described bags can be produced is accordingly restricted. Further, a closed bag end of the described character is not wholly satisfactory in that the end portions of the pleats in the folded over end portion of the bag are not adhesively secured to each other and thus permit the collected dust to seep therebetween.
In order to 'provide improved sealing of the bags at the closed ends thereof, it has been proposed to provide one or both of the ends of each pleated tube section with two or more transverse folds that are adhesively secured. However, where two or more folds are to be provided at each end of a tube section, such folds cannot be conveniently formed during the continuous movement of the ICC tube sections in the longitudinal direction. Thus, it becomes necessary to change the orientation of the tube sections with respect to their direction of movement, and this inherently limits the rate of production and increases the cost thereof, particularly when the closed bag ends are formed on a machine separate from the machine forming the pleated tube sections.
Further, the material required for the fold or folds at one or both ends of the bag may represent as much as one-third of the total material required to produce the bag.
In another form of disposable filter bags for vacuum cleaners, one or both ends of the pleated tube sections are closed by stitching the same transversely thereacross and then further sealing each closed bag end by means of a strip of gummed tape which is folded over amd covers the stitching. Although this form of filter bag avoids the waste of material required for the folded bag ends, there is no overall economy, as the transverse stitching of the bag ends and the application of the gummed tape thereover cannot be conveniently effected while the tube sections continue to move at high speed in the longitudinal direction. Thus, the production of the last described type of filter bag also involves either changing the orientation of the pleated tube sections with respect to their direction of movement or the transfer of the pleated tube sections to a separate machine for forming the closed bag ends, with inherent limitations on the rate of production and increases in the cost thereof, as previously mentioned.
Accordingly, it is an object of this invention to provide a bag havingV opposed panels connected at the sides by a plurality of pleats so as to be particularly suited for use as a filter bag in a vacuum cleaner, which bag has one or both of its ends securely and tightly sealed in a manner that permits the high speed and economical production thereof.
Another object is to provide a bag of the described character which permits the most economical utilization of the fibrous flexible material from which the same is formed.
A lfurther object is to provide a method and apparatus by which 'bags particularly suitable for use as disposable filter bags of vacuum cleaners may be produced at a high rate of speed and in a most economical manner.
In accordance with an aspect of this invention, a bag comprises a sheet of flexible fibrous material folded upon itself and having its longitudinal edges secured together in overlapping relation to form a tube having opposed panels connected, at the sides, by a plurality of pleats extending along the tube, such sheet having a stripe of adhesive extending completely across the face of the sheet which .is at the inside of the tube and being located adjacent an end of the tube to adhesively secure together the pleats as well as the panels at the end of the tube and thereby form a closed bag end.
In a method for producing the above described bag in accordance with this invention, adhesive is applied to one face of a continuous moving web of fibrous exible material in the form of stripes of adhesive extending transversely across the Web at locations spaced apart along the latter, and adhesive is also applied to the web along a longitudinal edge thereof, whereupon the web is folded upon itself about longitudinal fold lines. Such folding of the web overlaps the longitudinal edges of the web for attachment to each other by the adhesive applied along a longitudinal edge of the web, thereby to form a continuous tube having the transversely extending stripes of adhesive at the inside thereof and further having opposed panels connected, at the sides of the tube, by a plurality of pleats extending along the tube. Subsequently, the tube is pressed at at the location of each of the transverse stripes of adhesive therein so that the adhesive of each stripe there secures together the panels and pleats of the tube. Finally, the tube is cut transversely at least at the location of each of the transverse stripes of adhesive therein to form separated bags having closed bag ends defined by the stripes of adhesive.
In accordance with this invention, the adhesive applied to the continuous web in the form of transverse stripes is thermoplastic, and heat is applied to the tube simultaneously with the pressing thereof atV the location of each stripe to render the adhesive of the latter plastic for securely bonding together the panels and pleats.
The above, and other objects, features and advantages of this invention, will be apparent in the following detailed description of illustrative embodiments which is Yto be read in connection with the accompanying drawings,
FIG. l is a perspective view of a bag embodying this invention;
FIG. 2 is an enlarged perspective view of a pleated tube from which the bag of FIG. l is formed;
FIG. 3 is a fragmentary enlarged sectional view taken along the line 3-3 on FIG. l;
FIG. 4 is a schematic perspective view of an apparatus by which bags are produced in accordance with this invention; Y
FIG. 5 is an enlarged sectional view taken along the line 5--5 on FIG. 4;
FIG. 6 is a fragmentary perspective view schematically showing an additional adhesive applying device that maybe provided in the apparatus of FIG. 4; and
FIG. f7 is a sectional view similar to that of FIG. 3, but showing a bag in accordance with the invention produced on an apparatus having the additional adhesive applying device of FIG. 6. l
Referring to the .drawings in detail, it will be seen that a bag 10 (FIG. l) in accordance with this invention is formed of a sheet of exible material, such as, paper or other fibrous material which is preferably porous when the bag 10 is to be employed as a disposable filter bag for vacuum cleaners. The sheet 11 (FIG. 2) is folded a'bout longitudinal fold lines, so that its central portion forms a panel 12 connected, at its opposite sides, by a plurality of pleats 13a and 13b with longitudinal edge portions 14a and 14b, respectively. The longitudinal edge portions 14a and 14b extend inwardly towards each other so as to overlap at their edges, and a stripe 15Vof adhesive extends along one of the overlapping longitudinal edges for securing together the latter. It will be seen that the folded sheet 11 having its longitudinal edges secured together by the adhesive stripe 15 forms a tube 10a (FIG. 2) having opposed panels 12 and 14a, 14b connected, at
the sides of the tube, by a plurality of pleats 13a and 13b extending along the tube. A bag is formed from tube 11 merely by closing at least one end thereof. Y
In accordance with this invention, closing of an end of tube 10a is effected by providing the sheet 11, while in its flat form, with an uninterrupted stripe 16 of adhesive extending completely across the face of the sheet 11 which is at the inside of the tube 10a upon folding of the sheet and which is located adjacent the end of the tube 10a intended to form a closed bag end. Thus, when sheet 11 is folded to form the tube 10a, as shown on FIG. 2, the adhesive of stripe 16 will appearat the confronting surfaces of panel 12 and panel 14a, 14b, and also at s the confronting inner surfaces of pleats 13a and 13b for adhesively securing together |both the panelsV and pleats at the related end of the tube.-
The bag shown on FIG. 1 is a disposable filter bag for vacuum cleaners of the type having both of its ends 17 and 18 closed in the manner indicated above, and an aperture 19 cut in the panel 12 and surrounded by the usual reinforcing collar 20 of cardboard or other suhstantially rigid material to cooperate with a vacuum cleaner inlet.
4 Since the adhesive of each stripe 16 applied to sheet 11 before the folding thereof appears between the confront- Y of the finished bag, whereas the sheet 11 for forming the bag in accordance with this invention has a length equal to that of the finished bag and therefore effects the most to the sheet 11 prior to the folding of the latter, it is de- Y sirable that the adhesive of each stripe 16 be in a dry and, non-tacky condition during the folding operations to avoid smearing of the adhesive or interference with the folding. Thus, in accordance with ythis invention, each transverse stripe 16 is of a thermoplastic adhesive, that is, an adhesive that is rendered plastic or adherent by heat applied thereto after the folding of the sheet 11. By way of example, the adhesive of each transverse stripe 16 may be a hot melt or other thermoplastic. The hot melt is heated so as to be in a liquid condition when applied to the sheet 11 and, upon cooling, becomes solid and sub-V stantiallyV non-tacky so as to permit the folding of the sheet into the tube 10a. After such folding heat and pressure are applied at each end of the tube to be closed so as to again melt the plastic or hot melt for lbonding together the confronting inner surfaces of the panels and pleats.
Alternatively, the adhesive of each transverse stripe 16 may be of a rubber latex applied in liquid form and drying to a non-tacky, solid consistency before the folding of the sheet.V Thereaften'when heat and pressure are Y applied to the end of the tube to be closed, thegrubberbecomes plastic and is vulcanized for securely bonding having one or both of the ends thereof closed in accordance with this invention, as described above, may be produced automatically and at a high rate ofVV productionin an apparatus 21 employing, as the starting material, a.V Y continuous web W of sheet material which is unwoundY froma supply roll R. The web W being unwound from roll R moves continuouslyin the longitudinal direction and initially passes between die cylinders 22 and 23 which Vare suitably rotated and carry cooperating dies 24 for forming the apertures 19 of successive bags-at locations spaced apart along the web by a distance equal to the finished length of each bag. After passing between die cylinders 22 and 23, the web travels around a back-up roller 25 which is suitably rotated and serves to support the web during the application of the transverse stripes 16 of arl-V hesive by a device 26. v
The adhesive applying device 26 includes a reservoir 27 containing a supply of the adhesive, a pick-up roller 28 which is rotatably supported so that itslower Aportion dips into the adhesive supply, a rubber surfaced transfer roller 29 which is rotatably supported for Vrolling contact with take-up roller 28, and an applicator bar 30.`The applicator bar 30 extendsV parallel to, and is spaced radially from a support shaft 31 which is rotatably journalled lbetween back-up roller 25 and transfer roller 29 so that, during each revolution of shaft 31, applicator bar 30 first enters into rolling contact with the surface of roller 29 4to pick up adhesive from the latter and then effects rolling contact with the web on roller 25 for applying the adhesive to the web in a stripe extending completely across the web. Shaft 31 is suitably driven so that the peripheral speed of applicator bar 30 is equal to the speed of movement of the web, and the radial spacing of applicator bar 30 from the axis of shaft 31 is selected so that the circumferential distance traveled by the bar 30 during each revolution of shaft 31 is equal to the distance along web W between the transverse stripes 16 of adhesive successively applied thereto.
If the bags to be produced by the apparatus 21 are to be of the type shown on FIG. 1, that is, bags having both ends closed, the distance 'between the successive stripes 16 applied to web W is equal to the length of each bag. Further, the successive stripes |16 are located so that each aperture 19 is located midway between the adjacent transverse stripes.
If the adhesive employed for the transverse stripes 16 is a hot melt or thermoplastic, the reservoir or tank 27 is suitably heated, for example, by electric heaters (not shown) provided therein, so as to maintain the adhesive in a liquid condition until applied to the web by the applicator bar 30. Such adhesive dries to a non-tacky consistency on web W during movement of the web `from back-up roller 25 to an idler roller 32 which guides theweb to a back-up roller 33. Back-up roller 33 is suitably driven to support the web during the application of the longitudinal stripe 1S of adhesive to the web along one of the longitudinal edges thereof by means of the adjacent device 34.
The adhesive applying device 34 is shown to include a reservoir or tank 35 containing a supply of suitable adhesive, a pick-up roller 36 rotatably supported to dip into the supply of adhesive in reservoir 35, and a suitably driven adhesive applying wheel 37 which is rotatably supported to effect peripheral rolling contact with the surface of roller 36 for receiving adhesive from the latter and with the web W on back-up roller 33. If desired, adhesive applying wheel 37'may have a pair of parallel, spaced ribs extending circumferentially therearound so as to apply the adhesive to web W in the form of two narrow,
parallel bands which are spaced apart laterally by a small distance, and which are adapted to merge into the single stripe 1S of adhesive when the overlapped longitudinal edges of the web are pressed together, as hereinafter described. v
After the adhesive for the longitudinal stripe has been applied to the web, the latter moves continuously through a folding device 38 which may be of a conventional type, as shown. Such folding device 38 generally includes upright guide posts 39 (FIGS. 4 and 5) which are spaced apart by a distance approximately equal to the width of panel 12 of the finishing bag, and which operate to upwardly bend the lateral portions of the web. The device 38 furthergenerally includes inner and outer pleating plates 40 and 41 which are suitably supported, as at 42 and 43, respectively, and which act on the lateral portions of the web bent upwardly by the posts 39 to form the pleats 13a and 13b a'nd the inwardly directed, overlapping edge portions 14a and 14h of the tube 10a shown on FIG. 2. It Will be noted that thel folding of the web W to form the, tube causes the transverse stripes 16 to be disposed within the tube.
After the web W has been folded by device 38 into a continuous tube having opposed panels connected, at the sides of the tube, by pleats extending therealong, such tube passes between rollers 44 and 45which are suitably driven to pull the web through the folding device. The drive rollers 44 and 45 further press the tube flat and thereby achieve secure bonding of the overlapping edges of panel portions 14a and 14b "by the adhesive of stripes 15.
In order to effect closing of the tube at the locations of the transverse stripes 16 of adhesive within the tube, the latter travels continuously through a pressing and heating device 46'located along a section of the path of travel of the tube following the drive rollers 44 and 45. The pressing and heating device 46 includes pairs of upper and lower blocks 47a` and 47b engageable with the tube from above and below, respectively, and extending transversely across the tube.
The blocks 47a and 47b are respectively carried by chains 48a and 48b running around sprockets 49 which are rotatably supported so that the lower runs of chains 48a and the upper runs of chains 48b extend parallel to the path of movement of the tube 11 above and below the latter. Blocks 47a and 47b are spaced apart along the respective chains by a distance equal to the spacing between the adhesive stripes 16 within tube 11. The sprockets 49 are suitably driven in synchronism with the movement of tube 11 so that each pair of blocks 47a and 47b will move at the same speed as the tube while compressing the tube therebetewen at the location of a transverse stripe 16 of adhesive Within the tube. Each of the blocks 47a and 47b is further preferably heated, for example, by an electric resistance heater 50 disposed therein. Each heater 50 can receive energizing current through contacts 51 which engage tracks 52 extending'parallel to the paths of the respective support trains and being suitably connected to an electrical energizing circuit. f
. Thus, as tube 11 moves between the adjacent parallel runs of chains 48a and 4Sb, each of the stripes 16 of adhesive within the tube is subjected to heat and pressure by a pair of the blocks 47a and 47b to cause the thermoplastic adhesive of such stripe 16 to effect secure bonding together of the confronting surfaces of the panelsV and the confronting inner surfaces of the pleats of the tube.V
At the discharge end of the pressing and heating device 46, the tube 11 may be further engaged by drive rollers 53 and 54 which are suitably driven to ensure the continuous movement of the tube 11 at a uniform speed to a following cutting device 55. The cutting device 55, as shown, may include a fixed blade or anvil 56 disposed below the path `of movement of tube 11 and a rotary cutter 57 located above the tube 11 and capable of cooperating with the anvil 56 to transversely shear the tube 11. The rotary cutter 57 is suitably driven so as to cut the tube 11 when the length of the latter extended beyond the cutting edge of anvil 5,6 is equal tothe length of the bag to be formed.
l When the bags produced by the apparatus 21 are of the type shown on FIG.V l, that is, bags that are closed at both ends, rotary cutter 57 is driven so as to sever tube 11 along the medial line of each adhesive stripes 16 within the tube. Thus, half of each stripe 16 will form the closed bag end at one end of one bag, while the otherv half of the same stripe 16 will form the closed bag end at the adjacent end of the next bag being formed from the continuous tube 11.
However, if apparatus 21 is to be employed-for producing bags that are closed at only one end, then adhesive applying device 26 is driven so as to apply the transverse stripes 16 of adhesive to the web W with a distance therebetween equal to twice the length of each bag. In that case, rotary cutter 57 is driven to sever the tube 11 alongthe medial line of each stripe 16 and also along a transverse line` that is midway between the successive stripes 16.
The individual bags cut from the continuously moving tube 11 by the cutting device' 55 may drop into a receptacle 58, or may be further transported to an apparatus (not shown), for example, as disclosed in my co-pending application for U.S. Letters Patent, Ser. No. 417,611, tiled Dec. 11, 1964, by which a reinforcing collar 20 is applied to each bag.
It will beV apparent that, in the above described apparatus 21 conventional -mechanical transmissions, such as,
7 drive rollers 44 and 45, and 53 and 54 heating and pressing device 46 and cutting device y55. Such conventional drives have not been shown in order to simplify the drawing and thereby avoid confusion of the important -features of the apparatus with conventional mechanical elements.
In the apparatus 21 embodying this invention, all of the operations performed on the web W for producing lthe successive bags occur during the continuous movement of the web in the longitudinal direction so that a very high rate of production can be achieved. The possibility of effecting all of the bag forming operations during the high speed continuous movement of the web particularly arises from the closing :of the bag and merely yby the application of heat and pressure to the folded tube at the location of each transverse stripe of thermoplastic adhesive applied transversely across the web prior to Y the folding thereof.
' clude a reservoir 27a containing a supply of thermoplastic adhesive in liquid form, a pick-up roller 28a which is rotatably supported so that its lower portion dips into the adhesive supply, a rubber surfaced transfer roller 29a in rolling contact with pick-up roller 28a and applicators 30a mounted on a shaft 31a so that, during rotation of the latter, the bar-shaped applicators 30a pick-up adhesive from roller 29a and then apply such adhesive to the web W in the form of transversely aligned stripes 16a which are spaced from each other and from 'the` longi-y tudinal edges of the web. The device 26a is located so that applicator bars 30a engage the web during travel of the latterV over a back-up surface which may, for example, be constituted by the idler roller 32, as shown, and the distance from roller 32 to roller 33 should be sufficiently large to permit the stripes 16a to become solid or nontacky before reaching roller 33.
The stripes 16a are applied to the surface of `web W opposed to the surface receiving stripes 16, and device 26a is suitably driven so that each set of stripes-16a will register with a stripe 16 at the opposite surface of the web. Further, the applicator bars 30a are transversely dimensioned and located so that stripes 16a will appear onthe portions of web W destined to form the pleats 13a and 13b of the tube shown on FIG. 2.
Thus, when theweb W is folded, as described above, the adhesive of stripes 16a will lie between the confrontingV outer faces `of the pleats and will securely bond together such outer faces of the pleats, as shown on FIG. 7, when the tube is subjected to heat and pressureby the device 46 of FIG. 4.
Although the applicator bars 30a are shown in a form to provide two elongated stripes 16a of adhesive during each contact thereof with the web, such bars may be formed with spaced raised areas (not shown) to apply mere dots or spots of adhesive located to come between Vthe confronting outer faces of the lpleats, thereby effecting a saving" in the amounts of adhesive required for each bag. Y
Although illustrative embodiments of the invention have been described in detail herein with reference to the accompanying drawings, it is to be noted Ythat the inventionis not limited to those precise embodiments, and that various changesY and modifications may be effected thereinby one skilled in the art Without departing from the scope or spirit of the invention, except as defined in the appended claims.
What is claimed is: p l 1. A method of producing a bag from a sheet of flexible fibrous material comprising the steps of applying a stripe of adhesive to one face of the flexible material so that said stripe extends completely across the sheet adjacent an end edge thereof, applying adhesive to the opposite with said stripe of adhesive, applying adhesive to said sheet along a longitudinal edge thereof, folding saidr sheet upon itself to overlap the longitudinal edges for attachment to each other by said adhesive along a longitudinal edge, thereby to form a tube having said stripe of adhesive at the inside thereof and having opposed panels connected, at the sides of the tube, -by a plurality of pleats extending along the tube and having said spaced-areas of adhesive disposed between the confronting outer faces of the pleats, and pressing at said tube adjacent the end of the latter having said stripe of adhesive therein so that the adhesive of said stripe secures together said panels and the confronting inner faces of said pleats and said spaced areas of adhesive secure together said confronting outer faces of the pleats at said end of the tube and thereby form a closed bag end.
2. A method of producing bags from a continuous web of fibrous flexible material comprising the stepsfof apply-V ing adhesive to one face of said web in the form of stripes extending transversely across the web at locations spaced apart along the latter applying adhesive to the web along a longitudinal edge thereof, folding said web upon itself about longitudinal fold lines to overlap the longitudinal edges of the web for attachment to each other by said adhesive 'along a longitudinal edge, thereby to form a continuous tube having saidstripes at theV inside thereof and having opposed panels connected, at
the side of the tube, by a plurality of pleats extendingV `Y along the tube, pressing ilat said tube at the location of f each of said stripes of adhesive therein so that the ad-V hesive of each stripe there secures together said panels and pleats, and cutting lsaid tube transversely at least at the location of each of said stripes of adhesive therein to form separated bags having closed bag ends defined' by said stripes of adhesive.
3. A method according to claim 2; wherein said adhesiveapplied to the web in the form of stripes is thermoing and heating of the tube and said cutting of the tube, and wherein the adhesive applying, folding, pressing and heating, and-cutting operations are performed successively at spaced apart locations along said path.
5. A method according to claim 2; wherein said transverse cutting of the tube substantially bisects each of said stripes so that each stripe of adhesive forms closed bag ends for two bags. y K
6. A method according to claim 2; further comprising applying adhesive to the web at transversely spaced areas on the face thereof which is opposed to the face receiving said stripes of adhesive, with said areas of ad-A hesive registering, in the direction along the web, with said stripes so that, when the tube is pressed at at the location of each of said stripes, the corresponding transversely spaced areas of adhesive secure together the-confronting outer faces ofthe pleats.
7. VApparatus for producing lbags, from, a continuous web of brous flexible material, comprising means continuously moving said web along a predetermined path, means operative during the continuous movement of the web to apply adhesive thereto in the form ofrtransverse stripes extending across one face of the web at locations spaced apart along the web and in the form of at least one continuous longitudinal stripe along a longitudinal edge of the web, folding means acting on the `moving web after the adhesive applying means and being operative to fold the moving web upon itself to overlap and secure together the longitudinal edges of the web by means of said longitudinal stripe of adhesive so as to form a tube having said transverse stripes at the inside thereof and further having opposed panels connected, at the sides of the tube, by a plurality of pleats extending along the tube, pressing means moved with said tube along a section of said path and acting on said tube at the location of each of said transverse stripes therein to cause the latter to securely bond together said panels and pleats, and cutting means acting on said tube after the latter has moved through said section of the path to transversely cut said tube at least at each of said transverse stripes, thereby to divide said tube into bags having closed ends formed by said transverse stripes.
8. Apparatus according to claim 7; wherein at least said transverse stripes are of thermoplastic adhesive, and further comprising means heating said pressing means so that heat and pressure are simultaneously applied to the tube at the location of each of said transverse stripes to render the adhesive thereof plastic for ensuring secure bonding together of said panels and pleats.
9. Apparatus according to claim 8; further comprising means acting on said web in advance of said folding means to apply transversely spaced areas of thermoplastic adhesive to the other face of the web at locations corresponding to the transverse stripes, said spacedi areas of adhesive being transversely located relative to the web to come between the confronting outer faces of said pleats of the tube, whereby said heat and pressure also causes said spaced areas of adhesive to bond together the confronting outer faces ofthe pleats.
BERNARD ST ICKNEY, Primary Examiner.