US2237327A - Method of and apparatus for making bags - Google Patents

Description

April 8, 1941., R. M. BELL METHOD OF AND APPARATUS FOR MAKING: BAGS Filed larch 7, 1940 3 Shuts-Shoat 1 April 1941- R. M. BELL "ETHOD OF AND APPARATUS FOR MAKING BAGS 3 Shoots-Shoot 2 Filad larch '1, 1940 April 8, 1941. R. M. BELL IE'I'HOD OF AND APPARATUS FOR MAKING BAGS Filed larch 7. 1940 3 Shoots-Sheet 3 Patented Apr. 8, 1941 METHOD OF AND APPARATUS FOR MAKING BAGS Raymond M. Bell, Wayne, Pa., assignorto Benjamin C. Betner Company, Devon, Pa., a corporation oi Delaware Application March 7, 1940, Serial No. 322,716

4 Claims.

My invention relates to methods of and apparatus for making, from webbing, bags, liners,

, wrappers and the like, herein generically termed "bags" which are sealed, at least in part, by adhesive applied to the webbing from which the bags are made prior to detachment of the bags therefrom. I

In accordance with my invention, the webbing, of paper or other sheet material, during feed thereof is passed adjacent a smooth, unpatterned, surface, preferably the periphery of a roll, coated with adhesive which may be a molten film-forming material, a hot-metal thermoplastic, or of other kinds herein described; one face of the webbing is intermittently pressed into contact with the coating on the surface by structure engaging its opposite face and whose webengaging surface is of a pattern or configuration corresponding with the desired pattern of adhesive to be transferred to the webbing from aforesaid coated surface.

My invention further resides in the methods of and apparatus for making bags hereinafter described and claimed.

For an understanding of my invention, reference is had to the accompanying drawings, in which:

Fig. l, in perspective, illustrates a preferred method and arrangement for transferring adhesive to webbing;

Fig. 1a., in perspective, illustrates another method and arrangement for transferring adhesive to webbing;

Fig. 2 diagrammatically illustrates the apparatus of Fig. 1 and a bag-forming machine in combination;

Fig. 3 is a plan view of a portion of the web.- bing shown in Figs. 1, 1a and 2;

Figs. 4, 4a, 5 and 6, in perspective, illustrate successive steps of formation from the webbing of Fig. 3 of the completed bag shown in Fig. 6;

Figs. 7 and 8, in perspective, schematically illustrate arrangements for sealing bags; 7

Fig. 9 is a plan view of webbing to which has been applied patterns of adhesive different from those of Fig. 3;

Fig. 10, in perspective, shows a pressure-applying tool utilizable in transfer to the webbing of the patterns of adhesive shown in Fig. 9;

Figs. 11, 12 and 13, in perspective, illustrate successive steps of forming and sealing the bottom of a bag made from the webbing of Fig. 9;

Figs. 14 to 18, in perspective, illustrate the formation in accordance with my invention of various other types of bags.

Referring to Fig. 1, the webbing W may be of any sheet material suitable for making bags; for example, it may be of paper, coated, impregnated, or otherwise treated to procure enhanced strength, resistance to penetration by moisture or grease, or to procure any other desired characteristic; it may be any ordinary untreated paper; or it may be sheet film, such as Cellophane or the like.

Webbing W is fed from roll R over the idler rolls 2, I, and over the intermediate member 3 whose raised web-engaging surface is, in this modification, the substantially rectangular face of a bar or ridge 4 extending axially of roll 3 and projecting outwardly from the periphery thereof.

Once for each revolution of member 3, the bar or projection 4, pressing against one face of the web, moves it from the position shown in Fig. 2 to the position shown in Fig. 1, thus to effect contact of the opposite face of the web with the roll 5. The periphery of roll 5 is coated with adhesive, maintained, when of hot-melt type, in molten state by heat applied in any suitable manner; for example, the axle 6 of roll 5 may be hollow to allow passage into the roll, from any suitable source, of steam of suitably high tempera'ture.

Each time the web W is pressed against roll 5 there is transferred thereto a pattern, stripe or band of adhesive corresponding with or defined by the shape and extent of raised surface 4 of member 3, which pattern, in Fig. 1, is a band or stripe S extending across web W.

The surface of the web pressed against roll 5 is cold or of room temperature, and so tends to chill the adhesive, when of the hot-melt type, which it contacts, with the result the adhesive more readily transfers from. roll ii to the web.

The extent of feed of web W between aforesaid successive engagements of the bar 4 with the web depends, as will hereinafter appear, upon the lengths of the bags to be made and upon whether one or both ends of each bag is or are to be closed by the adhesive transferred from roll 5.

The peripheral speed of the roll 5 should be sufficiently high to insure presentation to web W for each of its successive contacts therewith of an increment of coated surface other than the one against which web ,W was pressed during the last prior revolution of member 3. When the web is fed continuously, the peripheral speed of roll 5 should approximate or equal the linear speed of the web to avoid relative wiping motion causing stringiness and irregularity of the pattern of adhesive transferred to the web.

The adhesive coating on roll 5 is continuously replenished by transfer thereto from the roll I which is to substantial extent submerged in'a mass of adhesive in fluid state held in reservoir 8, and therein maintained in fluid state, when of hot-melt type, by any suitable source of heat, for example, an electric heater 9A, Fig. 2, connected to a suitable source of current by cord 9 and plug ID.

The adhesives employed preferably are of the type known as "hot-melt, and those known as of lacquer or solvent types.

A' suitable hot-melt adhesive comprises an ethyl-cellulose base, 5% to 40%; a wax, such as Opal 10% to 50%; a natural or synthetic resin, 10% to 30%, and a chemical plasticiser, for example tricresylphosphate, 10% to 30%; it is comprised in the class known as Proxmelt.

There may be employed waxes which are themselves sticky; or waxes modified by incorporation of a resin, such as paracoumarone resin, rosin, or a modified rosin; or, the wax may be modified to give it adhesive properties by means of natural rubber, polymerized butadiene or polymerized isobutylene.

Suitable thermo sealing materials mayalso be made from the ethers' of cellulose, alone, or with modifying agents. Cellulose esters such as nitrocellulose may be used with resins capable of inducing thermo-plasticity. Also, resins may be used alone or with modifying agents. There may also be used suitable compositions made from the various resins derived from rosin, such as hydrogenerated rosin, and glycol and glycerol esters of rosin; also suitable molten film-forming agents from paracoumarone resins, shellac, polystyrene, and several of the resins derived from vinyl intermediates.

As a further specific operative example of molten film-forming material suitable for my process, there may be used the following composition: ethyl cellulose, 24 parts by weight; ester gum,

' phenol hardened, 16 parts by weight; dibutyl phthalate, 12 parts by weight; paraflln, 135 degrees, 22 parts; and fully hydrogenated cotton seed oil fatty acid, solid, 26 parts,

While the following description deals more particularly with hot-melt adhesives and adhesives consisting of molten film-forming materials. it shall be understood my invention is not I limited thereto and that other adhesives may be employed so long as they be of types suited not only to transfer thereof to the webbing by the herein described method and apparatus, but suited also to such other steps, purposes and conditions, subsequent to transfer to the webbing, as may be imposed by practical considerations.

Because the viscosity of such hot-melt adhes ves at temperatures for application to webbing W is high, as of the order of 2000 centipoises, it or other adhesives of too great viscosities or other characteristics is or are not wholly and effectively satisfactorily transferred to webbing by and directly from a stencil or equivalent coated therewith. Moreover, with the conventional stencil arrangement, the impression roll over which the web passes becomes heated, as by and due to repeated contacts with the webbing of the stencil, if heated to suit the adhesive employed, and the webbing is heated to a temperature sufficiently high to preclude proper transfer of adwith my arrangement, as above stated, the relatively low temperature of the webbing facilitates transfer of adhesive thereto, and its quick hardening thereon when of such type.

Reverting to Figs. 1 and 2, hot-melt adhesive. as it passes upwardly on the surface of roll I, is uneven and stringy because of its aforesaid high viscosity; however, due to squeezing of the adhesive between the rolls 5 and I, it is spread out or distributed to effect a smooth, even coating on the periphery of roll 5, so to insure transfer to the webbing of patterns of adhesive which are consistently similar to each other and to the surface configuration of the presser member 4, and which patterns are free of ridges of adhesive and of areas covered with insuflicient adhesive or bare. The thickness of the adhesive, whatever its type, transferred to the webbing may be accurately controlled or predetermined by adjustment, in any suitable manner, of the pressure between rolls 5 and I.

The hot-melt so transferred directly to the inner face of the web due to pressure on its outer face by member 4, solidifies almost instantly, so permitting the webbing to be folded, rolled, or otherwise manipulated or operated upon within a short time or at a short distance beyond the applying roll 5; it may, for example, pass at once into a printing press or to a bag-making machine. Solvents may be used with the hot-melt to impart fluidity, but in such case the webbing, after application of the adhesive, may need to be passed through one or more drying chambers before it can be folded or otherwise operated upon; however, such use of solvents, so requiring drying chambers, is unnecessary when the hotmelt is transferred by and in accordance with the apparatus and methods herein described.

In the modification shown in Fig. 1a, the rotating member 3 of Fig. 1 is replaced by the reciprocating member 3A whose web-engaging face 4A is shaped to correspond with the desired pattern of adhesive to be transferred from roll 5 to the webbing W. The mechanism, not shown, which reciprocates the member 3A intermittently to cause face 4A to press the webbing against coated roll 5, is so timed with respect to the continuous or intermittent feed of web W that there is obtained the desired spacing between the successive patterns of adhesive upon the webbing. For making bags having single bands or stripes of adhesive adjacent either their mouths and/or bottoms, the timing of member 3A is such that the spacing between successive stripes S upon web W substantially correspond with the length of a single bag blank; when each of the bags shall have a plurality of stripes of adhesive, the member 3A may either be replaced by one having a suitably differently shaped pressure member; i. e., one having a double blade extending transversely of the webbing; or the mechanism for operating member 3A may be of such character that it operates it at proper times during feed of the web to efiect transfer of the adhesive in stripes which are alternately close together,

and widely spaced, generally as shown in Fig. 8 of Haskell Patent 2,062,265.

Sharply to define the edges or boundaries of the patterns or stripes of adhesive applied to the web, in avoidance of irregularities in the adhesive pattern at its edges as may otherwise occur because of the viscosity or other phoperty of the adhesive, it is desirable that the web, after engagement thereof with the adhesively coated surface, shall not too rapidly recede therefrom as the pressure member itself recedes from position corresponding with maximum pressure of the web against thecoated surface. To this end, when the structure is of the character illustrated in Figs. 1 and 2, the distance between the axes of rolls 3 and 5, and the distance of the operative surface of member 4 from its axis of rotation or the extent of projection of member 4 beyond the periphery of the roll 3, are so relatively chosen or designed to procure sufficiently slow recession of the web from the surface or roll 5. When the structure is of the character fllustrated in Fig. 1a, the same result is obtainable by suitable construction of the cam or other mechanism which effects reciprocation of member 3A.

The webbing W, after transfer of the stripes S thereto, by mechanism of Fig, 1 or la,-may be rerolled on a storage roll for immediate or delayed transport to a bag-making machine, or, and preferably, as shown in Fig. 2, the webbing W, after leaving roll 5, continues its movement toward bag-making machine M, of any conventional type suited to make the particular form of bag desired. In either case, and particularly the former, the webbing, if of untreated stock, may, after solidification or setting of adhesive stripes S, be subjected to any coating or treating process to obtain enhanced strength, resistance to mois ture, or other desired characteristic, provided such treatment does not involve subjection of the adhesive to physical or chemical effects adversely affecting its properties or effectiveness when subsequently heated for bag-sealing purposes; otherknives i I, i2 into successive tubular blanks B.

Each of blanks B in passing between the rolls i3 and it receives from the reciprocating stencil i5 9. stripe D (Fig. 4a) of adhesive over and against which the leading end of the tubular blank is bent by cooperation of the folding knife l5 with notch or recess IS in the periphery of roll Id. The stencil i5 for each revolution of roll i3 engages the coated periphery of roll 30 to receive a coating of glue, paste or other solvent-type of adhesive which it subsequently in the revolution applies to a blank B; roll 30 which is in continuous rotation dips below surface of the adhesive in reservoir 3 l. The adhesive transferred from reservoir 3| and applied by stencil i5 is preferably of aforesaid type and not of the hot-melt type.

"The banks B discharged beyond the rolls i3, it fall upon belt l'l which, in cooperation with belt l8, transfers the blanks to a receptacle, such as hopper l9, and, during transfer, between belts i1 and IS, the folded bottom of each is held against the adhesive applied by stencil 15' for a time sufficient to insure sealing of the bottom of the bag; during their transport by and between stripes S which are spaced longitudinally of the webbing, Fig. 3. The longitudinal margins of the web W are shortly thereafter overlapped and joined by adhesive, preferably in a bag-making machine as previously described, to form a longitudinal seam A, Fig. 4, of a tube whose opposite sides may be tucked in to form gusset or reentrant folds C, C, Fig. 4. The tubing is cut, as by knives Ii, l2, Fig. 2, to form individual bag blanks, Fig. 4. The stripe D, Fig. 4a, applied across one exterior face of the bottom portion of blank B, preferably within a bag-making machine, may be any suitable solvent type of adhesive, or it may be of the hot-melt type, in which latter case it should be applied by an arrangement similar to that shown in Figs. 1

. or 1a of which it is characteristic the transfer of adhesive is effected not by a stencil, but by pressing the bag material against a smooth surface coated with hot-melt. When the adhesive applied at D is of the solvent type, the bottom of the blank B is substantially at once folded over stripe D, Fig. 5, and held in engagement for a length of time to insure setting of the adhesive; when stripe D is of hot-melt, the bottom of the bag may be closed at any suitable time after the application of stripe D by folding the bag bottom and applying pressure and heat thereto. Such subsequent formation of the bottoms of the bags may be of advantage because they may be shipped fiat, and because it permits formation of bags of somewhat different sizes from identical blanks, so to suit the bags to the needs of a particular customer or for particular materials or commodities to be enclosed in the bags, without need to maintain on hand a large assortment of bags of different sizes.

The mouth of the individual bags, Fig. 6, may be sealed, after filling, by pressing together the sides of the bag above the filling and concurrently applying heat thereto; for example, the mouth end of the bag may be fed between rolls 20, 2|, Fig. 7, either or both of them heated, or,

as shown in Fig. 8, the open end of the bag may.

be flattened between the plates or members 22, 23 either or both of which may reciprocate, and either or both of which may be heated.

When both the bottom and mouth of the bag blank are to be sealed by hot-melt" adhesive transferred from roll 5, the member 3 may be provided with an additional bar to provide, longitudinally of webbing W, pairs of more or less closely spaced stripes S of adhesive, one eventually to appear as a band within the mouth of one bag, and the other to appear as a band within the bottom-forming end of the succeeding blank formed from the webbing. In such case, each blank comprises a tubular section of webbing formed by adhesive joinder of the longitudinal margins of the webbing and within which, at opposite ends thereof, there are encircling bands or stripes of thermoplastic which can be reactivated by application of heat and joined to each other to form a seal by substantially concurrent application of pressure.

Although it usually is desirable that the stripe of thermoplastic applied to the webbing should extend entirely thereacross, so to provide within the mouth of each bag formed therefrom a band of adhesive which is continuous, for at least some purposes, the stripe may be discontinuous or extend only partly around the inner periphery of the bag blank; in such cases, the web-engaging surface 4 or 4A of the web-actuating member 3 or 3A will be correspondingly modifled in shape.

When the bags to be made from the webbing W, Fig. 9, are of the so-called automatic" or self-opening type, the blade .or bar 4, Fig. 1, is replaced by the two bars 4a, 4b, Fig. 10, of suitably different lengths to effect transfer from roll 5 to the webbing for each revolution of member 3 two stripes SI, S2, Fig. 9, of adhesive whichare in substantial alignment with each other transversely of the webbing. Before, or preferably after, application of a pair of stripes SI, S2, the webbing is slitted, as at E, E, to provide, upon severance of the webbing at El, a flap F whose purpose will later appear in discussion of Figs. 11 to 13.

The longitudinal margins of the webbing are adhesively joined at A, Figs. 11 to 13, to form a succession of tubular blanks whose opposite sides are tucked or folded in, in suitable manner, as by mechanism known in the art, to form gusset or reentrant folds C. The leading end of each tubular blank is in turn folded, as shown in Fig. 11, to provide four. bottom-forming panels F2, F3, F4 and F5, the last-named including aforesaid flap F, defined by folding along lines Bf, Bf. To close and form the bag bottom, the panel F3 is moved from the position shown in Fig. 11 toward and beyond the position shown in Fig. 12 to bring the under face thereof into engagement with panels F2, F4 and to effect overlying relation of the portions of stripes Si, S2 on the under face of panel F3 upon the portions of stripes Si, S2 of adhesive on the panels F2, F4; the panel F5 is thereafter folded from the position shown in Fig.- 12 to the position shown in Fig. 13 to effect engagement of that portion of stripe S2 on panel F2 with the portion of the same stripe on panel F5, and to effect engagement of that portion of stripe SI on panel F5 with the portion of "the same stripe on panel F4, and also to effect engagement of flap F with that portion of stripe SI on flap F3 visible in Fig. 12. While the panels are so folded, Fig. 13, they are subjected to heat and pressure so to effect an adhesive-to-adhesive bond of panel F3 with panels F2 and F4., and an adhesive-to-adhesive bond between panel F5 and panels F2 and F4, and to effect engagement of flap F with the adhesive on panels F2, F3 and F4.

If it is desired that the mouth of the bag, Fig. 13, also be provided with a band of adhesive, suited to seal it after filling of the bag, the member 3, Fig. 10, may be provided with additional bar structure suitably angularly spaced with respect to bars 4a, 4b to provide, in addition to stripes SI, S2, continuous stripes, such as transverse strips S of Fig, 3.

As shown in Fig. 11, the adhesive stripes SI and S2 are continuous from end to end, and especially so across the folds or fold lines Bf, Bf; these stripes being so applied in continuity, in the method or apparatus of either Fig. 1 or Fig. la, i. e. before the adhesively striped webbing is formed into a bag destined to be of the selfopening type, there are prevented the unavoidable gaps in the continuity of adhesive stripes formed adjacent the fold lines, such as Bf, Bf, which gaps heretofore have been occasioned by the fact the adhesive stripes, generally like SI, S2, are applied after the tube has been folded, as shown in Fig. 11, and is pinched at the fold lines Bf, Bf. In brief, by applying the stripes SI s2 in continuity, as appearing in Fig. 11, when first applying adhesive to the webbing, before formation thereof into a bag, there are avoided the aforesaid gaps which are occasioned by aforesaid late application of the adhesive stripes during the formation of the bottom of the bag.

By transversely cutting the webbing, Fig. 3. along substantially the middle of each stripe S, there are formed blanks, such as shown at B3 in Fig. 14, each having along each of its longer margins a stripe S3 of thermoplastic adhesive. The blank B3 is transversely folded, as shown at Z in Fig. 14, substantially midway of its length, to bring into overlying relation those areas of the blank which, upon application of heat and pressure thereto, form the side seams or seals G, G, Fig. 15

To make this type of bag, Fig. 15, though it is desirable that the stripes S extend entirely across the webbing, Fig, 3, it sufilces if they extend from one edge of the webbing to the center or fold line Z, or preferably at least to slight extent beyond it.

The severance of the webbing W to form the blanks B3 is effected after hardening or setting of the adhesive S, but since this is a matter of relatively short time, as of seconds, the web W may be immediately passed from the roll 5, Fig. 1, to the knife or shearing device, such as H, i 2 of Fig. 2, which forms the blanks B3 by cutting transversely through the webbing along substantially aforesaid middle of the width of the successive stripes S.

The stripes S4 of adhesive, Figs. 14 and 15, which may be applied to the webbing longitudinally thereof when it is desired to seal the mouths of the bags after filling, are preferably of hotmelt, and may be applied by a reciprocating pressure-applying member generally similar to that shown in Fig. 1a and which operates upon the web between successive feeding movements thereof.

More generally stated, when the adhesive is applied to the webbing as a transverse stripe, Fig. 3, the feed of the web may be continuous, as in Figs. 1 and 2; but when the applied stripe of adhesive, such as S4, Fig. 14, is to extend parallel to the direction of feed of the webbing, the web should be at rest between successive movements of feed thereof when pressed by a pressure-applying tool corresponding with member 3A of Fig. 1a, against a plate or other structure coated with hot-melt; alternatively, the web may be in motion during transfer of hot-melt thereto provided that the pressing tool and the coated member are, during their engagement with the web, moving with it and at substantially the same speed. Otherwise, because of the viscous character of the "hot-melt, the transfer is unsatisfactory and the patterns are stringy, irregular, and non-uniform in appearance.

The bag shown in Fig. 16 may be made from the webbing striped as shown in Fig. 3 by folding its longitudinal margins into adhesive engagement with each other to form longitudinal seam A; except that the sides of the tubular blank so formed are not folded or tucked in, it is similar to the blank B shown in Fig. 4. One end of the tubular blank B4 is folded and flattened to form the bottom of the bag, generally in the manner shown in Figs. 4a and 5; the bottom may be held so folded by adhesive suitably applied, as at D, either manually or, Fig. 2, during passage of the webbing through mechanism suitable for makingthis type of bag. The blanks B4 are so cut from the webbing, as by knives H, l2, Fig. 2, that each of them has adjacent its mouth one of the internal bands or stripes S of thermoplastic adhesive which, at any time, after filling of the bag, may be reactivated by subjecting it to heat and pressure, as in Fig. 7 or Fig. 8, to seal the mouth of the bag.

The blank B5 for making a square or gusseted bag, Figs. 17 and 18, is, before folding, similar to blank B3 of Fig. 14. After each blank, B5, Fig. 17, is cut from the web W, Fig. 3, it is first folded lengthwise along the lines X, XI, Y, Yi, and then folded crosswise along the line Z to bring into engagement with each other the faces of the outwardly-turned panels H, Fig. 18, coated with stripe or stripes S3 of thermoplastic adhesive. The side seams J, J are formed by application of heat and pressure to the outside faces of the pairs of panels H, H.

When it is desired to provide for sealing of the mouth of the bag B5, after filling thereof, each. of the blanks has adjacent and parallel to its opposite narrow edges a transverse band or stripe S it, preferably of hot-melt, applied generally as described in connection with Figs. 1, 1a and 2. Thus, when blank B5 is folded as shown in Fig. 18, the ends of stripes 84 are joined at H so to form a continuous band or ring of adhesive extending completely around the inside of the bag adjacent its mouth, with the end portions of each stripe 54 extending half way across the gusset fold C, i. e. to the inner edge of each panel H. After filling of the bag, the mouth is sealed by flattening the top portion of the bag above the contents and applying heat and pressure thereto, for example by an arrangement similar to that shown in Fig. '7 or 8, so

to unite with each stripe S4 its aforesaid end portions, and to unite the two stripes S4 throughout their lengths between their said end portions.

From all the foregoing, it is evident that various other types of bags, and liners, wrappers and the like, as well may be formed from webbing prepared by transfer thereto of patterns of thermoplastic or other adhesive by arrangements of the characters of those exemplified by Figs. 1, lo and 2; it is therefore to be understood my invention is not limited to formation of bags or the like of the kinds specifically illustrated and described, but is coextensive in scope with the appended claims.

I disclaim from the scope of the appended I claims those methods and mechanisms characterized by impression of adhesive on one face of the web by pressure exerted on its opposite face by an uncoated pressure-applying surface whose configuration and extent are different from the configuration and extent of the applied adhesive.

Certain of the herein described bags and methads of producing them are claimed in my divisional application, Serial Number 380,859, filed February 27, 1941.

What I claim is:

l. A method of operating upon webbing for production of bags therefrom which comprises feeding the webbing, coating an unpatterned surface with thermoplastic adhesive, intermittently pressing the webbing, at intervals spaced in the direction of its feed, between said unpatterned coated surface and a patterned uncoated surface to effect transfer to the webbing from said unpatterned coated surface of adhesive in predeter-' adhesive thereon, feeding webbing adjacent said so-coated surface, and intermittently, at intervals spaced along it in the direction of its feed, pressing the webbing by an uncoated surface into contact-with the molten adhesive on said coated surface to effect transfer thereof to the webbing in predetermined patterns corresponding in extent and configuration with said uncoated surface.

3. A method which comprises heating solid thermoplastic adhesive to temperature sufficient to transform it into molten state with high vis cosity, spreading the viscous molten adhesive upon a surface at temperature sufficient to prevent substantialsolidification of the adhesive thereon, feeding adjacent said so-coated surface webbing from which are to be produced bags having seals, intermittently, at intervals spaced along it in the direction of its feed, pressing the webbing by an uncoated surface into contact with the molten adhesive on said coated surface to effect transfer thereof to the webbing in predetermined patterns corresponding in extent and configuration with said uncoated surface, and, after setting of the transferred adhesive, cutting and shaping the webbing to form bags each having exposed within it at least part of. one of said patterns of thermoplastic adhesive.1

4. The combination with mechanism for making bags from webbing and means for feeding the webbing thereto, of a roller adjacent the path of feed of the webbing and coated with molten viscous thermoplastic adhesive, means for heating said roller to maintain said adhesive molten, a member having a web-engaging surface shaped to define the pattern of adhesive transferred to said webbing, and means operating in timed relation to said web feeding means intermittently to press said surface of said member against one face of the Webbing to effect contact of the opposite face thereof with the coating on said roller for transfer of molten adhesive to the webbing in a series of patterns.

RAYMOND M. BELL.

Images