US3297234A - Plastic bag with inlet valve - Google Patents

Description

Jan. 10, 1967 KARL-HElNZ HONSEL ETAL 3,297,234

PLASTIC BAG WITH INLET VALVE 2 Sheets-Sheet l Filed July 6, 1965 auf.: am

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PLASTIC BAG WITH INLET VALVE 2 Sheets-Sheet 2 Filed July 6, 1965 FIG.7

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United States Patent O 3,297,234 PLASTIC BAG WITH INLET VALVE Karl-Heinz Honsel, Bielefeld, Paul Maurer, Beckum,

and Karl-Friedrich Duwe, Oberkassel, near Bonn, Germany, assignors to PSG Plastik-Sack G.m.b.I-I., Rosbach (Sieg), Manel, Germany, a limited-liability company of Germany Filed July 6, 1965, Ser. No. 469,472 13 Claims. (Cl. 229-625) The invention relates to plastic bags for packaging solid materials, such as powdered and granular objects, having formed therein a valve structure which permits the materials to be introduced and,which valve closes automatically to prevent the escape of solid material. The invention is especially applicable to filling plastic bags that are initially entirely closed save for the said valve.

Prior bags made of sheets or tubes of plastic materials usually had one end initially open, to be closed only after filling. Apart from the necessity of closing such bags, e.g., by folding and stapling, by Welding, or by the use of adhesives or cords, such bags must be distended before filling because they are made and transported in fiat condition.

It would be desirable to avoid the operations of distending the bag prior to lling and of sealing after filling, and much time can be saved by simply pushing a filling nozzle or spout into the bag and introducing the material through the nozzle. This would present a great advantage particularly when subdivided material, such as cement, flour, grain or fertilizer are packaged, both by saving time and operations and by reducing dust in the atmosphere. Prior attempts to attain this result have not been technologically successful.

A desirable characteristic of such a valve structure for filling a bag is that the valve be applied to a fiat part of the bag, so that the bags can be manufactured and stored in flat condition before use. It is essential that such a valve be economical. Further, it is desirable that such a valve structure can be applied to the bag with a minimum waste of the plastic material of Which the bag is formed.

Plastic bags are often formed of tubular stock which may include a seam but, more usually, is in the form of a sock, which is a seamless tube extruded from a die and inflated until it has the requisite circumferential dimension and is cooled, and thereafter pressed fiatly and Wound as a double layer on a roll. Much of such stock is wasted by overlaps of the fioor that includes overlapping flaps and, moreover, according to known constructions may be reinforced by an insert.

Further, it is often desirable to permit air or other gas to seep out slowly from the bag while essentially confining the solid materials. This permits the escape of air that may be introduced into the bag with the goods or formed from the goods and which, if not relieved, can bloat the bag and/or give it poor stackability.

The principal object of the invention is to provide a bag of plastic material having a part thereof that forms a bounding Wall of the bag formed as a valve structure which is adapted to receive a filling nozzle or spout through which material can be introduced, said valve being self-closing to prevent the escape of material from the bag. Ancillary thereto, it is desired to form the valve so that it may lie fiat when the bag is folded or collapsed; and/ or to construct it for the facile insertion of the lling nozzle; and to provide a valve that seals the bag to prevent entry of moisture, either as a liquid or as aircarried Water vapor.

A further object is to provide a valve structure that f ICC permits the escape of air or gas from the bag, to the exclusion of solid materials within the bag.

Still another object is to attach the valve to the bag in a manner that insures structural stability and security against leaks while avoiding Waste of plastic material, especially the stock that is used to form the side body of the bag. Ancillary ther'eto, it is an object to mount the valve so as to constitute a transverse Wall or fioor when the bag is distended, said wall or floor being folded against and parallel to the fiat side body when the bag is folded.

In summary, the plastic bag according to the invention includes a peripherally closed side body of plastic material, e.g., made of a tube, and has at least one closed end and a valve structure that includes a plurality of juxtaposed sheets or layers of plastic material of which at least the innermost is flexible, formed with displaced incisions so as to provide juxtaposed portions of said sheets between the incisions that lie in sealing relation save during filling of the bag, said valve structure being attached in sealed relation to a suitable part of the side body and forming a bounding part of the bag.

A filling nozzle can be inserted into the incision in the outermost sheet to separate the said juxtaposed sheet portions, and material can be injected into the bag through the nozzle and the several incisions. When the nozzle is withdrawn, the valve closes by the engagement of the said juxtaposed sheet portions, which are forced into sealing engagement by the force of solid material within the bag against the innermost of said layers, thereby preventing escape of solid material.

It is evident that both ends of the bag may be initially closed, save for the said valve structure, whereby no sealing or bag-closing operation is necessary after the bag is filled. When the bag is thus initially closed except for the valve, the latter is advantageously situated at or near the top of the bag, e.g., forming the upper end closure thereof. However, the invention is further conf cerned with the valve construction to be described and such a valve is applicable also to bags having an end that is initially open and which is closed by suitable means before filling, or which is closed after filling, the nozzle and valve being then used merely to inject a blast of air into the bag to distend it and facilitate loading.

In another aspect, the invention resides in a valve structure that forms a transverse, foldable Wall of the bag at an end thereof. This is useful particularly when the bag is of the type having a rectangular cross section and has a foldable fioor at one end. When such a bag is collapsed, it is folded along one or along three parallel, vertical crease lines at each end and the rectangular floor or transverse wall together with a triangular-shaped part of the bag side wall, situated at each end of said rectangular floor or wall, is folded to lie parallel to the juxtaposed side walls of the folded bag (the said triangular parts forming parts of the bag end Walls when the bag is distended). The construction according to the preceding paragraph effects an economy in the use of plastic material. This economy is enhanced by forming the bag side body with narrow flaps that project from the end of the bag side walls between the said triangular parts and lie fiatly against the marginal parts of the valve in non-overlapping relation, to leave a major part of the valve sheets uncovered.

The advantage of this construction lies in the fact that a much shorter length of the tubular stock is required to construct the side wall and its connecting appendages for forming the transverse w-all or fioor than in conventional constructions that provide fold-over floors: only very narrow flaps project beyond the ends of the side body,

in contrast to the wide over-lapping Lbase flaps commonly used to form a floor, and the transverse wall is formed essentially by -the sheets of the valve.

The innermost sheet of the valve structure may be formed of thinner material than the other foils and may have a width greater than the valve structure to provide marginal strips, suitably having widths equal to the said flaps on the bag side body, that are folded about the margins of the other sheet or sheets of the valve and lie atly against the marginal parts of the outermost sheet and are situated between said marginal parts and the said flaps; the ends of all sheets of the valve stucture then lie inwardly of the said triangular parts of the bag. The several parts mentioned are interconnected in sealed relation to the bag side body by any suitable means, usually by weldments. The term welding is used herein to denote the formation of a seal by the application of heat, if desired together with pressure, causing the thermoplastic materials to unite. However, other sealing imeans, such as the application of adhesives or strips of tacky and chemically similar strips of plastic material, are contemplated. When adhesives are used they must usually be applied in heated condition and the means for applying them must also be heated.

In a preferred embodiment the valve structure comprises three juxtaposed sheets of which the two outer sheets are formed from the same tube of plastic material (usually seamless) that is creased and pressed atly to bring the opposite parts into flat engagement. Each of these parts has an incision, and the incisions in the said parts may be mutually displaced and situated so that the incision formed in the intermediate sheet lies longitudinally between the incisions in the innermost and outermost sheets. The foil of which such a tube is formed can be considerably thinner than the foil used for a single outer sheet and can, further. lbe Imore easily worked into the lbag to form an end wall. Further, the incisions in the two outer layers, when offset, provide an additional valve that seals the bag when the said layers close on each other by juxtaposition of the parts between the said displaced incisions.

To permit air to escape from the bag after lling, for the purpose of preventing a bloated outline and for facilitating stacking the filled bags with reduced tendency to slip on each other, according to the invention the valve may be provided with an air-escape passageway that is preferably restricted and/or tortuous, so that only a slow seepage of air occurs and the entrainment of ne solid materials is minimized or wholly prevented lby the size of the passageway, In a specific embodiment to be described, utilizing the three-layer valve construction, the two inner sheets of the valve are sealed to one another, e.g., welded along a transverse line at one side of both of the incisions in the two inner sheets, to isolate a space that is situated between bounding parts of said sheets, and the innermost sheet has perforations through which air can enter the said space from the bag. The said perforations are advantageously small, eg., smaller than the particles of solids contained Within the bag, if this is feasible. The said isolated space communicates with the outside of the bag through a passageway that extends about the longitudinal margin of the two outer valve sheets at least at one side thereof and thence longitudinally between the outer face of the outermost sheet and the marginal strip trip of the innermost sheet (or, when such a strip is not provided, the Hap of the bag side body) -along the laterally outer side of the marginal weld seam or seal line, the said seam or seal line being displaced inwardly from said margin of the valve sheets. The longitudinal channel thus provided between the seam and the edge is open at the end near one or both of said triangular parts of the bag.

The incisions are prefera'bly substantially parallel slits that extend transversely across the sheets. Simple cuts, not involving the removal of any sheet material, are preferred for all incisions save that in the outermost sheet; the latter may be fonmed to provide a lip that is folded over on itself from the incision edge nearer the other incisions and is secured in flat engagement with the outermost sheet. The lip thereby reinforces the outer sheet at the incision and gives a nite width to the incision, which facilitates insertion of the filling nozzle.

To aid in guiding the filling nozzle through the several displaced incisions or slits, that edge of each incision in each sheet except the outermost which is remote from the incision in the outermost sheet is structurally connected to the next outer sheet, e.g., by a weld seam. This connection prevents the nozzle from overshooting or entering the dead pocket between the juxtaposed sheets beyond the incision or, when a shorter nozzle is inserted, aids in the ow of the material discharged therefrom into the proper incision and, therethrough, into the bag.

The invention will be further described with reference -to the accompanying drawings forming a part of this specification and showing two preferred embodiments, wherein:

FIGURE l is a perspective view of a .part of a Ibag with the end portion folded, prior to applying the valve structure thereto;

FIGURE 2 is a plan of the bag end with the valve structure partly aiiixed, before folding the flaps;

FIGURE 3 is a longitudinal section taken on the line 3-3 of FIGURE 2;

FIGURE 4 is a plan of the completed bag and valve;

FIGURE 5 is a fragmentary transverse section taken on the line 5*5 of FIGURE 4;

FIGURE 6 is a plan of a completed bag and valve showing another embodiment which uses three sheets;

FIGURE 7 is -a longitudinal section taken on the line 7-7 of FIGURE 6;

FIGURE 8 is a transverse section taken on the line 8-S of FIGURE 6;

FIGURE 9 is an enlarged fragmentary plan of a part of FIGURE 6; and

FIGURE 10 is a bottom plan of the valve, viewed from the interior of the bag.

In the several views the sheets of plastic material are shown by heavy solid lines and shown separated, for clarity, and the weldments are indicated in section lby xs and in plan lby parallel lines extending the weldment seams. It will be understood that these representations are only to indicate the construction, and that in practice the sheets are flatly juxtaposed and the weldments occupy no space,

FIGURE 1 shows the upper part of a bag formed of a tube 11 of thermoplastic material of width W (half circumference) terminating at an upper edge 12 which lies in a plane perpendicular to the tube axis, said tube forming the side ybody of the bag and including triangular parts 13, 14. The tube 11 is shown creased at diametrically opposed, vertical lines 15 meeting the outer apices of the triangles; this brings the opposite sides of the body together flatly along a line 16. It will be understood that it is also possible to fold the bag on other lines; thus, in manufacture the bag normally includes convex creases along the chained lines 17 which terminate at the inner apices of the triangles, and concave creases at the lines 15, such folding being well understood in the art of bagmaking. The marginal parts of the side body provide narrow aps 18, 19, demarcated by chain lines, the said chain lines being the fold lines described hereinafter.

Referring to FIGURES 2-5, the valve structure forms a transverse wall at the upper end of the bag and comprises an outer, preferably thick sheet 29 of plastic material which has the same width as the finished valve, i.e. equal to the distance between the chained fold lines of the aps 18, 19, in FIGURE 1. The valve further comprise an inner sheet 21, preferably of a very thin foil, having the same length as the sheet 20 but wider to provide marginal strips 22, 23, of widths equal to the flaps 18, 19, respectively. Both sheets and 21 underlie the margins of the triangular part- s 13, 14, as is shown in FIGURE 3, the ends of these sheets being pushed into place. The ends of these sheets are then sealed to said triangular parts, e.g., by applying heat, if desired together with pressure, along seams 24, 25, which extend transversely across the sheets. It will be noted that these seams provided weldments that join together three juxtaposed layers of plastic.

The outer sheet 20 is, prior to assembly, formed with a transverse incision 26 which is shaped to provide a lip 27 that is folded over on itself and is structurally secured to lie flatly against the sheet by a weld seam 28. Thereby the incision 26 has a substantial width and its edge at the lip 27 is reinforced against damage lwhen engaged by the nozzle. The inner sheet 21 is, prior to assembly to the bag, formed with a transverse incision 29 that is displaced from the incision 26 when the sheets are assembled. Although for clarity the incision 29 is shown to have a finite width, in the preferred device it is simply a cut without removal or folding of material. The sheets 20 and 21 are structurally joined, either before or after assembly to the `bag 11, by a transverse weld seam 30 at the edge of the incision 29 that is remote from the incision 26.

After applying the seams 24, 25, the flaps 18, 19 are folded, together with the strips 22, 23, to cause the latter to lie atly against t-he outer face of the outer sheet 20, as appears in FIGURES 4 and 5. Seals, such as weldments along seams 31, 32, are applied to join together the four juxtaposed sheets. These seams extend the full length of the valve sheets between the triagular portions 13, 14.

In use, assuming the lower end of the bag (not shown) to be closed, and the bag to be initially in empty, collapsed condition, a filling nozzle (not shown), connected to suitable supply means for the material to be packaged, is inserted into the incision 26, thereby separating the sheet portions 20 and 21' situated between the incisions 26 and 29 to permit the material to enter the bag through the latter and gradually distend it. When the nozzle is of sufficient length it extends into the bag. The seam 30 insures passage of the material-and also of the nozzle, if long enoughinto the incision 29 without entry into the inter-layer space beyond the incision. When the bag is lled to the desired extent the nozzle is withdrawn `and the said portions 20 and 21 move together into llat juxtaposition to seal t-he bag, this sealing action being aided by the pressure of the contents of the bag against the inner sheet. This seal further prevents entry `of moisture, liquid as well as air-carried moisture vapor, into the bag where it could damage the contents, such as cement or hygroscopic material.

The construction shown in FIGURES 6-10 differs from the foregoing in that the valve structure comprises, instead of a lsingle, relatively thick outer foil, a plurality of thinner sheets formed from a single tube of plastic material `which is preferably seamless; further, this embodiment includes the optional air-escape means. Reference numbers 11-14, 18 and 19 denote part previously described. The two outer layers 33, 33a, are flatly pressed, opposite sides of the samepplastic tu-be created along diametrically opposite lines as appears in FIGURE 8, and formed with longitudinally displaced, slit-shaped transverse incisions 26a and 34. The former is formed with a lip 27a, folded over on itself and secured by a seam 28a; the latter is preferably merely a cut, made without removal or folding of material. The innermost sheet 21a has the outline previously described for the sheet 21, having marginal strips 22a and 23a, which are folded about the creases of the tube to lie flatly against the outer face of the sheet 33, inside of the flaps 18, 19. The sheet 21a has a transverse slit-shaped incision 29a, formed as described above for the incision 29. The incision 26a, 34 and 29a are mutually displaced and arranged in the order stated.

Each pair of juxtaposed sheets are structurally interconnected on the sides of the incisions 34 and 29a remote from the incision 26a by weld seams 35 and 30a, to facilitate passage of the filling nozzle and material into the bag. Consequently the nozzle can be pushed through the incision 26a and thence through the incisions 34 and 29a while the seams 35 and 30a insure the proper direction, as previously described.

The stack of three sheets is vconnected to the side body 11 by transverse end seams 24a, 25a, and longitudinal seams 31a, 32a, corresponding to the seams 24, 25, 31 and 32 and similarly formed. However, in this embodiment, when the air-escape feature is used, as described below, at least one, and preferably, both seal seams 31a and 32a are positioned inwardly from the outer longitudinal margins of the valve sheets to provide a longitudinal channel 37 between the seam or seams and the margin or margins, said channel being open at the end thereof toward the triangular part 13, asfshown by the arrow 36 in FIGURE 9 (and also, if desired, at the other end toward the triangular part 14). This channel is indicated at 37 in FIGURE 8, and extends between the underside of the strip 22a (and 23a, if desired) and the outer face of the sheet 33. It may be noted that, as is indicated in FIGURE 8, the weldment seams 31a and 32a interconnect only the ap 18 (or 19), strip 22a (or 23a) and the outer most sheet 33; connection to the sheet 33a is optional `but not necessary, while the latter sheet and the underlying sheet 21a are preferably avoided at least in part to provide an air-escape passage.

The valve according to the second embodiment operates in the manner previously described save that it provides two valves in series. Thus, when the iilling nozzle is withdrawn, the parts of the sheets 21a and 33a between the incisions 29a and 34 move into juxtaposition; similarly, the parts of the sheets 33a and 33 between the incisions 34 and 26a move into juxtaposition. Both are aided in their sealing actions to prevent escape of materials by the pressure exerted outwardly against the sheet 21a by the said materials.

To permit air to escape from the bag, there is provided a transverse seal seam, such as the seam 38, extending fully across the valve which interconnects the two inner sheets 21a and 33a to one side of both the incisions 29a and 34, to isolate a space between the said sheets on the side of the seam 38 away from said incisions. A plurality of holes 39 is formed in the sheet 21a to establish communication between the interior of the bag and the said space. cation with the outside by one or more tortuous passageways extending about the margins of the sheet 33a to the longitudinal channel(s) 37 (FIG. 8) and the end opening(s) 36 (FIG. 9). The holes 39 permit gas to enter the said isolated space to effect a slight and localized separation between the sheets 21a and 33a. The holes 39 may be made small enough to prevent the passage of solid material; however, in the case of nely powdered material such as cement reliance is had on the slow movement or seepage of air, which entrains only a negligible amount of powder which, further, is trapped by the tortuous passageway, so that little or no powder escapes to the outside. When the solid material presses against the part of the sheet containing the holes 39 little seepage of air occurs.

It is evident that while the incisions 26a, 34 and 29a are large to permit rapid lling of the bag, the holes 39 and its connecting exit passages are restricted.

Further, certain seams were shown to interconnect only some of the juxtaposed layers or sheets. For example, the seams 31a and 32a do not connect the innermost sheet 21a to the sheet 33a, and the transverse seam 38 does not connect any sheet above the sheet 33a. Such seams can be made by inserting implements that lie adjacently to the stack of sheets to be welded together, while applying pressure thereto, the said implements hav- The said space is in communiing only the sides thereof next to said stack heated, so that any sheet adjacent to the unheated face of the implement is not heated sufiiciently to bring it to the fusion or softening temperature and, moreover, the absence of pressure will prevent thel formation of a tight seal.

We claim as our invention:

1. A bag of plastic material having a peripherally closed side body and an end closure, at least a part of said bag being formed as a valve structure for the insertion of a filling nozzle, said valve structure including:

(a) at least two parallel, juxtaposed sheets of plastic material that constitute a terminal part of said bag, are separate from said side body, and are sealed to said body,

(b) each of said sheets being formed with an incision, the incisions in different sheets being displaced from each other so that the sheet portions between incisions in different sheets lie in flat, juxtaposed relation to form a seal against the escape of material from the bag,

(c) the incision in the outermost sheet being accessible to the outside of the bag for the insertion into the incision therein of a filling nozzle to separate the said portions for introducing said material into the bag through the incisions, and

(d) the end of said side body which is adjacent to said terminal wall including a pair of narrow fiaps that lie flatly against and are in sealed relation to the outside of said terminal wall and are in laterally spaced relation to each other.

2. A bag as defined in claim 1 wherein the innermost of said sheets is thinner than said outermost sheet, has a width greater than the width of said terminal wall, and includes marginal strips that extend about the margins of the outermost sheet and lie in fiat engagement with the outer face thereof between said outer face and the inner faces of said aps, the said fiaps, marginal strips and outermost sheet being mutually sealed.

3. A bag as defined in claim 1 wherein said incisions are elongated slits extending'transversely to the axis of displacement of said incisions and the innermost sheet is structurally connected to the adjacent sheet along the edge of the slit in the innermost sheet that is remote from the slit in the outermost sheet.

4. A bag as defined in claim 1 wherein said incision in the outermost sheet is an elongated slit having that edge thereof which is nearer to the incision in the innermost sheet formed as a lip, said lip being bent over on itself and being structurally secured to said outer sheet in fiat relation thereto for reinforcing the said slit.

5. A bag of plastic material having a peripherally closed side body and an end closure, at least a part of said bag being formed as a valve structure for the insertion of a filling nozzle, said valve structure including:

(a) at least two parallel, juxtaposed sheets of plastic material that constitute a bounding part of said bag and are sealed to said body,

(b) each of said sheets being formed with an incision, the incisions in different sheets being displaced from each other so that the sheet portions between incisions in different sheets lie in fiat, juxtaposed relation to form a seal against the escape of material from the bag,

(c) the incision in the outermost sheet being accessible to the outside of the bag for the insertion into the incision of a filling nozzle to separate the said portions for introducing said material into the bag through the incisions,

(d) means including the innermost of said sheets delining an enclosed space, said innermost sheet having at least one small aperture formed therein for the fiow of gas from the interior of the bag into said enclosed space, and

(e) a passageway formed in said bag interconnecting the said enclosed space with the outside of the bag.

6. A bag as defined in claim 5 wherein:

(a) the said sheets constituting the valve are sealed to the side body along seal seams at least one of which is situated inwardly from the margin of the sheets and leaving between said margin and said seam a passage that is open to the outside of the bag, and

(b) said enclosed space is in communication with the said passage by a path that constitutes a part of said passageway.

7. A bag as defined in claim 5 wherein the said valve structure includes at least three sheets of plastic material, the said enclosed space being bounded by the innermost sheet and the sheet adjacent thereto.

8. A bag as defined in claim 1 wherein said valve structure comprises three juxtaposed sheets of plastic material, each of said sheets having an incision formed as an elongated slit extending transversely to the line joining said incisions, said slits being situated at progressively displaced positions to provide between each pair of adjacent incisions juxtaposed sheet portions to form seals.

9. A bag of plastic material having a peripherally closed side body and an end closure, at least a part of said bag being formed as a valve structure for the insertion of a filling nozzle, said valve structure including:

(a) at least three juxtaposed sheets of plastic material that constitute a bounding part of said bag and are sealed to said body, the two outer of said sheets being formed of a single tube of plastic material having the opposite parts thereof pressed fiatly against each other and being integrally joined at the lateral edges thereof,

(b) each of said three sheets being formed with an incision, the said incisions being displaced from each other so that the incision in the innermost and outermost lsheets are on opposite sides of the incision in the intermediate sheet, to provide portions of juxtaposed sheets between each pair of incisions that lie in fiat, juxtaposed relation to form seals against the escape of material from the bag, and

(c) the incision in the outermost sheet being accessible to the outside of the bag for the insertion into the bag of a filling nozzle to separate the said juxtaposed portions for introducing material into the bag through the said incisions.

10. A bag as defined in claim 9 wherein said incisions are elongated, substantially parallel slits and each pair of juxtaposed sheets is structurally interconnected along that edge of the slit in the relatively inner sheet of the respective pair which is remote from ythe incision in the outermost sheet.

11. A bag as defined in claim 9 wherein:

(a) said incisions are elongated and extend transversely across said sheets,

(b) the innermost and intermediate sheets are mutually sealed along a transverse line situated to one side of both the incisions in the innermost and intermediate sheets to isolate a space that is enclosed by bounding parts of the mutually sealed sheets situated on the said side of the transverse seal line,

(c) said bounding parts of the innermost sheet being formed with small perforations extending therethrough for admitting air from the bag into the said space, and

(d) said space being in communication with the outside of the bag by a passageway that extends about at least one of said lateral edges of the tube forming the two outermost sheets.

12. A bag as defined in claimv 11 wherein:

(a) said bag side body includes at one end thereof which is adjacent to said valve structure a pair of narrow, lateral aps situated outwardly from said outermost sheet at the lateral margins thereof and in parallel relation to said lateral edges of the tube lthat constitutes the two outermost sheets, and

(b) said aps are sealed to said outermost sheets along marginal seal lines at least one of which is displaced inwardly from the respective lateral edge, the longitudinal space between the said seal line and the part of the ap adjoining the bag valve immediately outward from said outermost sheet being open to the outside of the bag,

(c) whereby said passageway between the space dened in paragraph (b) 1of claim 11 and the outside extends about the outside of at least one of said lateral edges and thence through the said longitudinal space.

13. A bag as defined in claim 12 wherein:

(a) said sheets constitute a terminal wall of the bag and are situated transversely to the axis of said side body,

(b) said innermost sheet has a width greater than the Width of the outer sheets and includes marginal strips that extend about the said lateral edges and References Cited by the Examiner UNITED STATES PATENTS 3,195,801 7/ 1965 Symons et al. 229-625 3,197,119 7/ 1965 Hartig et al 229-625 3,201,029 8/ 1965 Batosti et al. 229-625 3,220,635 11/ 1965 Kasting et al. 229-625 FOREIGN PATENTS 861,352 12/1952 Germany.

20 JOSEPH R. LECLAIR, Primary Examiner.

DAVID M. BOCKENEK, Examiner.

Claims (1)

1. A BAG OF PLASTIC MATERIAL HAVING A PERIPHERALLY CLOSED SIDE BODY AND AN END CLOSURE, AT LEAST A PART OF SAID BAG BEING FORMED AS A VALVE STRUCTURE FOR THE INSERTION OF A FILLING NOZZLE, SAID VALVE STRUCTURE INCLUDING: (A) AT LEAST TWO PARALLEL, JUXTAPOSED SHEETS OF PLASTIC MATERIAL THAT CONSTITUTE A TERMINAL PART OF SAID BAG, ARE SEPARATE FROM SAID SIDE BODY, AND ARE SEALED TO SAID BODY, (B) EACH OF SAID SHEETS BEING FORMED WITH AN INCISION, THE INCISIONS IN DIFFERENT SHEETS BEING DISPLACED FROM EACH OTHER SO THAT THE SHEET PORTIONS BETWEEN INCISIONS IN DIFFERENT SHEETS LIE IN FLAT, JUXTAPOSED RELATION TO FORM A SEAL AGAINST THE ESCAPE OF MATERIAL FROM THE BAG, (C) THE INCISION IN THE OUTERMOST SHEET BEING ACCESSIBLE TO THE OUTSIDE OF THE BAG FOR THE INSERTION INTO THE INCISION THEREIN OF A FILLING NOZZLE TO SEPARATE THE SAID PORTIONS FOR INTRODUCING SAID MATERIAL INTO THE BAG THROUGH THE INCISIONS, AND (D) THE END OF SAID SIDE BODY WHICH IS ADJACENT TO SAID TERMINAL WALL INCLUDING A PAIR OF NARROW FLAPS THAT LIE FLATLY AGAINST AND ARE IN SEALED RELATION TO THE OUTSIDE OF SAID TERMINAL WALL AND ARE IN LATERALLY SPACED RELATION TO EACH OTHER.

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