US3889871A

US3889871A - Recloseable flexible bag

Info

Publication number: US3889871A
Application number: US335796A
Authority: US
Inventors: David B White
Original assignee: ES&A Robinson Canada Ltd
Current assignee: ES&A Robinson Canada Ltd
Priority date: 1972-09-07
Filing date: 1973-02-26
Publication date: 1975-06-17
Anticipated expiration: 1992-06-17

Abstract

The invention provides a recloseable bag formed of flexible sheet material comprising a front wall and a rear wall sealed together adjacent at least one of a pair of opposite edges thereof, said bag including in a wall thereof an elongated deformable member, such as a metal wire, extending transversely of said edges to provide for repeated closure of the bag, the ends of the elongated member being spaced from said edges of the bag and the sheet material between the ends of the member and the said edges of the bag being removed. The invention also provides a method of producing said bags.

Description

United States Patent 11 1 ml 3,889,871

White 1 June 17, 1975 1 RECLOSEABLE FLEXIBLE BAG 2.8lll,l8ll 7/1957 Rumsey. Jr 426/412 2.1197729 8/1959 Ashton ct 221.... 93/8 WA Inventor: Dav! B. White, WIHUWdilic, Adams 4 V I I I n X Canada 3.321.126 5/1967 Rivman ct al v. 229/65 i 3.402.052 9/1968 Walker 229/87 B X [73] Asslgnec' aigz i bgfig (Lanada) 3.543.999 12/1970 Kugler 1 A r v. 229/63 x 3.687.357 8/1972 Hansen .1 229/63 122] Filed: Feb. 26. 1973 Primary E.ruminerWi1liam 1. Price 12]] Appl 33s796 Assistant E.raminer-Stephen P7 Ciarbe Related US. Application Data Almrney, Agent, or Firm-Stevens. Davis. Miller & [63} Continuation-impart of Ser, Nov 288,434 Sept 12. Mosher 1972, Pat. No. 3,859,895

[57] ABSTRACT [30] Foreign Application Priority Data The invention provides a recloseable bag formed of Sept, 7. [972 Canada 151 54 flexible sheet material comprising a front wall and a rear wall sealed together adjacent at least one ofa pair 52 5. CL 229 5; 93 3 w 229 37 13; of opposite edges thereof, said bag including in a wall 229 7 425 105; 42 412 thereof an elongated deformable member, such as a [51] Int. Cl a. 865d 33/30 metal ir x nding transversely of said edges to [58] Field 01 Search 229/65. 63 62, 87 B, 87 R; provide for repeated closure of the bag, the ends of 150/3 11; 426/4; 106; 93/1 T5. 35 DS 3 WA the elongated member being spaced from said edges of the bag and the sheet material between the ends of {56] Ref n Cited the member and the said edges of the bag being re- UNITED STATES PATENTS moved. The invention also provides a method of producing said bags. 594 235 11/1897 Eaton 229/65 65l,937 6/1900 Short U 229/65 15 Claims, 19 Drawing Figures PATENTEDJUN 17 ms SHEET PATENTEDJUH 17 ms SHEET FIG. I

FIG. l2.

RECLOSEABLE FLEXIBLE BAG This application is a continuationin-p2irt. in the nature of a divisional. of application Ser. No. 288.434. filed Sept. 12. 1972 now US. Pat. No. 3.859.895.

The present invention relates to bags formed from flexible sheet material, particularly thermoplastic sheet material, such as polyolefins. preferably polyethylene and a method of producing such bags. In particular the present invention relates to recloseable flexible sheet bags which can be repeatedly closed subsequent to the breakage of the top seal thereof.

Flexible sheet bags such as thermoplastic sheet bags have heretofore been produced inter alia by continuously passing a pair of superimposed layers ofthe sheet material, which layers are suitably formed by longitudinally folding a single sheet of the thermoplastic material. along a defined path to a cutting and sealing station where the layers are cut and sealed. suitably by a vertically moving hot knife. transversely to the direction of motion of the layers in the defined path. which hot knife cuts and seals the sides of the bag to form side seams. During the passage along the defined path of the layers to the cutting and sealing station they may be longitudinally sealed adjacent to one end thereof to provide a header for the bag. the bottom of the bag being left unsealed for the insertion ofthe contents into the bag. When the bag has been filled the bottom of the bag is subsequently sealed. However. such bags have the disadvantage that once the top seal is broken to gain access to the contents of the bag the bag is not recloseable.

A recloseable bag has been shown in US. Pat. No. 2.973,] 31 to Mead et al. which includes the presence of an opening and closing means including a tab which extends across the bag adjacent the top end thereof. the tab extending beyond the side seams of the bag and including wire therein as a deformable member. While this tab is effective in providing for repeated reclosing of the bag. the closure means has to be attached to each individual bag after it has been fabricated, i.e., after the cutting and sealing station which necessitates increased handling of the bag and thus substantially increases the cost of the production of the bag.

British Pat. No. l.263.76l published Feb. l6. 1972 to T(.F Canada Ltd. discloses a recloseable bag in which the bendable metal wire extends longitudinally of the bag to provide for reclosing of the bag.

The present invention provides a bag which includes a closure means for rendering the same repeatedly openable and close-able after the rupture of a seal in which less material is necessary to provide the closure means and in which the closure means can be incorporated into the bag during the course of its conventional manufacture without increased handling thereof.

It has now been found according to the present invention that by applying and sealing a continuous elongated deformable member. particularly metal wire. to the outer face of one of the layers. particularly in the aforesaid process. the member being disposed substan tially parallel and adjacent to but spaced from an edge during its passage along the defined path and by punching holes through said layers where the member inter sects the portion of the layers which are subsequently cut at the cutting station whereby the knife does not have to cut through the member thus avoiding damage thereto. a flexible bag is produced including a closure means rendering the same recloseable. In addition thereto it is found that by providing such holes in the bag communication may be provided between the interior of the bag and the external atmosphere whereby it is possible to avoid entrapment of air in the bag when the bottom of the bag is subsequently sealed.

According to the present invention there is provided in a recloseable bag formed from a flexible sheet comprising a front wall and rear wall sealed together at or adjacent at least one of a pair of opposite edges thereof. said bag including in a wall thereof an elongated deformable member extending transversely of said edges to provide for repeated closure of the bag. the improvement in which the ends of the elongated member are spaced from said edges of the bag. the sheet material between the ends of the member and said edges of the bag being removed.

in accordance with one embodiment of the present invention the pair of opposite edges are the side edges thereof both of which are sealed. the elongated defornr able member extending transversely of said side edges adjacent to either the top or bottom of the bag.

In a particularly preferred embodiment oof the pres ent invention the front wall and the rear wall are sealed together adjacent the top thereof. said wire providing for subsequent repeated closure of the bag after rupture of the seal adjacent the top thereof and said removed sheet material providing for communication between the interior of the bag and the outside atmosphere. The bag of the embodiment may be in its fillable form and has a scalable open bottom and is suitably provided with a flap to enhance the scaling of the bottom thereof or alternatively the bag may be filled with the goods to be packaged. such as cookies, and has a sealed bottom. The bag may also be provided with a reinforced header attached to the top thereof as is conventional.

In an alternative embodiment of the present invention the bag has a closed bottom. said wire being dis posed in a flap portion of the rear wall extending beyond the front wall.

Again, the bag ofthis alternative embodiment may be in fillable form and has a scalable top or alternatively the bag may be filled with the goods to be packaged and has a sealed top.

In a still further embodiment of the present invention the pair of opposite edges are bottom and top edges of the bag at least the bottom edge of the bag being sealed. the deformable member extending transversely f said edges and longitudinally of the bag suitably in the center thereof in a similar manner to the aforesaid British patent.

The present invention also provides a method of making a recloseable bag of a flexible sheet material which comprises continuously passing two superimposed layers of said sheet material along a defined path to a sealing station and a cutting station where said layers are sealed and cut transversely of their direction of travel to form a pair of opposite edges of said bag and during passage along said defined path continuously passing an elongated deformable member to and sealing said wire on the face of one of said layers substantially transverse to said edges and continually punching holes through said layers at the points where the member intersects the portions of the layers which are subsequently cut at the cutting station.

In forming the bag with the deformable member transverse to the side edges thereof the superimposed layers may be cut and scaled simultaneously by a hot knife to form a weld or can be cut subsequent to scaling using a cold knife in which case the seal generally lies slightly inwardly from the side edge of the bag.

In pro\iding the bag according to the preferred enibodiment of the present invention the layers during passage along the defined path are continuously longi tudinally sealed ad acent one edge thereof to form the top of the bag. the elongated member being sealed on the outer face of one of said layers essentially parallel to and spaced from said longitudinal seal.

In providing the bag according to the alternative embodiment of the present imention the superimposed layers are continuously formed by longitudinally folding a single sheet of said material to provide a flap portion in one of such layers extending beyond the other layer. said elongated member being sealed in the adjacent llap portion,

In forming the bag with the deformable member transverse to the bottom and top edges of the bag the seals on the side edges of the bag are formed without cutting or the superimposed layers are in the form of a continuous tube. The bottom edge only of the bag may be cut and scaled using the hot knife as the top edge must be provided open for the insertion ofthe contents of the bag and is then sealed. This may be achieved by having the sealing station separate from and upstream of the cutting station, a coid knife being u ed at the cutting station. Alternatively this may be achieved by the use of a hot knife providing a weld at the bottom of the bag which operates on a timed sequence alternately with a flying knife so as to weld and cut the superimposed layers alternately.

The flexible material is preferably a thermoplastic material whence the side, top and bottom seals of the bag are suitably heat seals, the seals suitably being produced by a hot knifei Particular thermoplastic materi' als which may be mentioned include polyoletins, par ticularly polyalkylencs. preferably lower polyalkylenes and more preferably polyethylene. The elongated deformable member is preferably a metal wire.

In accordance with one embodiment of the present invention the wire is sealed to the surface of said layer by means of an adhesive tape which is continuously passed to the face so as to be superimposed on the wire and the tape is subsequently pressed into contact with the face to seal the wire to the face In another embodiment of the present invention, where the sheet material is a thermoplastic material, a thermoplastic strip is continuously passed to the face so as to be superimposed on the wire and the strip is heat sealed to the face to seal the wire to the face,

In yet a further embodiment of the present invention where the sheet material is a thermoplastic material, a gusset is continuously formed in the layer containing the surface. the wire being continuously introduced into the gusset and heat sealed therein.

The present invention will be further il ustrated by way of the accompanying drawings in which:

FIG. 1 is a perspective view of a bag according to on embodiment of the present invention;

FIG. 2 is a vertical section through a bag according to an alternative embodiment of the present invention;

FIG. 3 is a perspective view of a bag according to yet another embodiment of the present invention;

III

HG, 4 is a perspective view partially broken away in vertical section ofa bag according to a still further embodiment of the present invention.

I IG. 5 is a schematic perspective view of an apparatus useful in making the bag according to the embodiments of the invention set forth in FIGS. I and 2;

FIG. 6 which is on the same sheet ofdrawings as FIG, I. is a detail ofthe apparatus according to FIG. 5 show ing a method ofattaching the wire to the bag according to one embodiment of the present invention using an adhesive tape:

HG. 7 which is on the same sheet of drawings as FIG. I. is a detail ofthe apparatus according to FIG, 5 showing a method of attaching the wire to the bag according to another embodiment of the present invention using a thermoplastic tape;

FIG. 8 is a detail of an apparatus according to FIG. 5 showing a method of attaching the wire to the bag ac cording to yet a further embodiment of the present invention by means of a gusset;

FIG. 9 is a schematic perspective view of an apparatus useful in making the bag according to the embodiment of the invention set forth in FIG. 3;

FIG. 10 is a schematic perspective view of an apparatus useful in making the bag according to the embodi ment of the invention set forth in FIG. 4:

FIG. I] is a perspective view of a bag according to another embodiment of the present invention;

FIG. I2 is a perspective of a bag similar to that in FIG. 11 but with a different bottom edge seal:

FIG, 13 is a schematic perspective view ofan appara tus for making the bag of FIG. II; and

FIG. 14 is a schematic perspective view of an apparatus useful for making the bag of FIG, I2.

Referring to FIGS. 1 and 2 the bag which is suitably formed of polyethylene has a front wall I and a rear wall 2 and has heat seals 4 along the side edges thereof and a heat seal 5 adjacent the top thereof. The bottom of the bag has a flap 6 and is open. The bag may be filled through the open bottom with the desired contents and the flap then turned up and heat sealed as at 7. In the unfilled state with the open bottom, the flap 6 has holes 8 therein by which the unfilled bag may be suspended. At the top of the bag there is suitably provided a false header 9 which includes a hole 10 by which the filled bag may be suspended after the flap 6 has been scaled.

Referring particularly to FIG. 1 the bag includes a metal wire I] held in place on the front wall I by a tape 12 which may be an adhesive tape or a thermoplastic tape which thermoplastic tape is heat sealed to the front wall 1 of the bag. At the side edges of the bag semicircular holes 13 have been punched out which has also removed the ends of the wire I] and also provides communication of the interior of the bag with the external atmosphere and thus prevents entrapment of air when the bag is closed by sealing the flap 6.

Referring specifically to FIG. 2 in an alternative embodiment the wire II is held in place in a heat sealed gusset [4 in the front wall 1 of the bag.

The bags of FIG. I may be made with the apparatus of FIGi S in combination with that of HG. 6 or 7 and that of FIG. 2 with the apparatus of FIG. 5 in combination with that of FIG. 8.

Referring to FIG. 5 sheet polyethylene 20 is withdrawn from a roll 2|. The sheet 20 contains printed portions 22 which form the false header 9 in the finished bag. The sheet 20 is folded at folder 23 into superimposed

layers

24 and 25, the lower layer 25 extending beyond the upper layer 24 to form the closeable flap 6 in the finished bag. The folded sheet 20 passes from the folder 23 over tensioning rolls 26 and is contacted by a header edge sealer 27 to provide the seal 5 in the bag. The flap 6 in the lower layer 25 has holes 8 punched therein by punch 28 and the false header 9 has holes punched therein by punch 29. The folded sheet finally passes through nip rolls 30 and vertically reciprocating hot knife 31 to provide the edge seals 4 in the bag. Instead of the hot knife 31 the heat seal may be made separately at or adjacent the edge 4 and then separately cut with a knife. The procedure as set forth heretofore constitutes the standard method of making the bag. In accordance with the present invention the metal wire 11 is fed to the upper layer 24 of the sheet 20 from a reel 32 and is sealed thereto by the techniques shown in FIGS. 6, 7 or 8.

Referring specifically to FIG. 6, adhesive tape 12 is fed from reel 33 to overlay the wire 11 on the layer 24 and tape 12 is pressed into sealing contact with the layer 24 by pressure roller 34.

Referring to FIG. 7 thermoplastic tape 12 is passed from reel 35 to overlay the wire 11 on the layer 24 and is maintained in contact by pressure roller 36 and heat sealed to the layer 24 by hot pressure roller 37.

Referring to FIG. 8 a gusset 14 is formed in the upper layer of the sheet 24 by a pair of

rigid arms

38 and 39. Arm 39 extends between the layers 24 and and arm 38 extends into the gusset 14. the metal wire 11 from reel 32 is fed into the gusset 14 and the gusset 14 is then heat sealed by hot pressure roller 40.

Referring once more to FIG. 5 punch 41 punches out hole 42 in the

sheets

24 and 25 at the points where the wire intersects the portion of the

layers

24 and 25 to be cut by the hot knife 31, thus avoiding damage to the knife during the cutting operation.

The bag of FIG. 3 comprises a front wall 1 and a rear wall 2 and has heat seals 4 along the side edges thereof. The top of the bag is open and the bag may be filled through such top opening with the desired contents and the opening subsequently heat sealed. The rear wall 2 includes a flap 50 having a metal wire 11 held in place on the inside surface thereof by a tape 12 which may be an adhesive tape or a thermoplastic tape, the latter being heat sealed to the flap 50, and semi-circular holes 13 are punched at the side edges of the bag, which holes have removed the ends of the wire 11. The flap 50 serves to reclose the bag when the sealed opening is broken to remove a portion of the contents.

Referring to FIG. 4, the flap 50 is double folded at 51 and 52. The top of the bag is open and is filled with the desired contents through the opening which is then heat sealed. Metal wire 11 is attached to the flap 50 and is held in position on the inside surface of the flap 50 by a tape 12 as shown in FIG. 3 and semi-circular holes 13 are provided as in FIG. 3. The flap is thus ofa double thickness.

The bag of FIG. 3 may be made with the apparatus of FIG. 9 in which polyethylene sheet 20 is withdrawn from a roll 21 over tensioning rolls 3 and is folded at folder 23 into superimposed

layers

24 and 25, the lower layer 25 extending at 53 beyond the upper layer 24 to form the flap 50 in the finished bag. The folded sheet 20 passes from the folder 23 over tensioning roll 26 and then through nip rolls and vertically reciprocating hot knife 31 to provide the edge seals 4 in the finished bag. Metal wire 11 is fed to extension 53 of the lower layer 25 from a wire reel 32 and sealed thereto by the techniques shown in FIGS. 6, 7 or 8 described previously. A punch 41 punches out holes 42 in the extension 53 at the points where the wire 11 intersects the portion of the extension 53 to be cut by the wire knife 31 thus avoiding damage to the knife during the cutting operation.

The bag of FIG. 4 may be made with the apparatus of FIG. 10 in which polyethylene sheet 20 is withdrawn from a roll 21 under tensioning rolls 3 and during passage between a lower and upper tensioning roll 3 is contacted by rigid folding arm 54 which institutes the fold 51 into one edge of the sheet 20 and then rigid folding arms 55 which introduce the fold 52 into the folder portion 51 formed by the arms 54. The sheet 20 so folded is further folded at folder 23 to form an upper layer 24 and a lower layer 25, which upper layer 24 extends beyond the lower layer 25 at 53 to form the double width flap 50 in the finished bag of FIG. 4. The folded sheet 20 passes from the folder 23 under tensioning roll 26 and then through nip rolls 30 and vertically reciprocating hot knife 31 to provide edge seals 4 in the finished bag. Metal wire 11 is fed to the extension 53 of the upper layer 25 from a reel 32 and is sealed thereto by the techniques shown in FIGS. 6 or 7 as described previously. Punch 41 punches out holes 42 in the extension 53 at the points where the wire 11 intersects the portion of the extension 53 to be cut by the knife 31, thus avoiding damage to the knife during the cutting operation.

Referring to FIG. 11, the polyethylene bag comprises a front wall and a rear wall 61 sealed adjacent the bottom edge 63 thereof by a heat seal 64. The upper end of the bag is open at 65 for the insertion of the contents thereof and ise then sealed. A metal wire 66 extends longitudinally of the bag and is held in position on the front wall 60 by an adhesive or thermoplastic tape 67, the thermoplastic tape being heat sealed to the front wall 60 of the bag. At the bottom edge 63 of the bag and the top edge 68 of the bag, semi-circular holes 69 are punched out which also removes the ends of the wire 66 and provides communication with the external atmosphere thus avoiding entrapment of air when the bag is closed by sealing the top edge 68.

Referring to FIG. 12 the bag is identical to the bag of FIG. 11 except the sea] at the bottom edge 63 is a weld seal.

The bags of FIG. 11 and FIG. 12 are produced by the apparatus set forth in FIGS. 13 and 14 wherein a continuous flattened tube of polyethylene 82 is withdrawn from a supply roll 71 and has applied to one surface thereof a metal wire 66 from a supply 72, the wire 66 being attached to the surface of the bag by means of an adhesive tape by the technique shown in FIG. 6 or a thermoplastic tape by the technique shown in FIG. 7. A punch 73 punches holes 74 in the tube 82 at points where the wire 66 intersects the portion of the tube 82 to be cut by the cold knife 75 or hot knife 77 thus avoiding damage to the knife during the cutting operation.

In FIG. 13 the bottom of the bag is sealed by hot bars 76 before cutting by downstream cold knife 75 to produce seals 64 in the bag of FIG. 11. In FIG. 14 tube 82 is alternatively cut by hot knife 77 to form the bottom edge 63 of a pair of bags each with weld seal and then by upstream flying knife blade 78 on chain 79 driven by sprockets 80 in timed sequence to form unsealed open tops 65 of the pair of bags which are subse quently sealed after insertion of the Contents ofthc bag.

Heretofore, there has generally been disclosed a recloseable bag formed for a flexible sheet material comprising a front wall and a rear wall scaled together at or adjacent to at least one pair of opposite edges thereof. the bag including in a wall thereof an elongated deformable member extending transversely of the edges to provide for repeated closure of the bag in which the ends of the elongated member are spaced from the edges of the bag. the sheet material between the ends of the member and the edges of the bag being removed.

In the embodiments specifically shown in the drawings, the bag before filling has one end thereof sealed and the other end thereof open for filling of the bag with its contents which end may subsequently be sealed or closed by the elongated deformable member which is located in a wall of the bag adjacent the open end The present invention also specifically includes bags open at both ends thereof for insertion of the contents such as are used in cooking meat and poultry in ovens, which bags are sometimes referred to as oven sheaths, the open ends of the bag being closeable by elongated deformable members in a wall of the bag adjacent each open end of the bag.

According to a particular embodiment of the invention therefore there is provided in a closeable bag formed of flexible sheet material comprising a front wall and a rear wall sealed together at or adjacent to both of the side edges thereof and are unsealed at the top and bottom edges thereof, said bag including in a wall thereof, an elongated deformable member extending transversely of said side edges adjacent each unsealed edge to provide for closure of said bag, the improvement in which the ends of each elongated member are spaced from the edges of the bag. the sheet material between the ends of each member and the edges of the bag being removed.

The present invention also provides a method of making such a bag of flexible sheet material which comprises continuously passing a pair of superimposed layers of said sheet material along a defined path to a sealing station and a cutting station where said layers are sealed and cut transversely of their direction of travel to form a pair of opposite side edges of said bag with the bottom and top edges thereof open and during passage along said defined path continuously passing an elongated deformable member to and sealing said member on the face of one of said layers transversely of said side edges adjacent each open edge and continually punching holes through said layers at points where the member intersects the portion of the layers which are subsequently cut at the cutting station.

The superimposed layers may be formed of two separate sheets. Alternatively, the superimposed layers may be formed from a single sheet folded in half during its passage along the defined path and the sheet is slit along the fold. Further, the superimposed layers may be formed from a single sheet by folding over its longitudinal edges to lie in abutment with each other during passage along the defined path, the sheet being slit longitudinally along each fold and also along the center between the adjacent abutting edges.

The further particular embodiment of the present invention will be further illustrated by way of FIGS. 15 to 19 of the accompanying drawings in which;

FIG. 15 is a front elevation of an oven sheath accord ing to one embodiment of the present invention;

FIG. 16 is a front elevation of an oven sheath according to the alternative embodiment of the present inven tion;

FIG 17 is a schematic perspective view of an apparatus useful for making the oven sheath of FIG. 15 and 16 according to one embodiment of the present invention;

FIG. 18 is a schematic perspective view of an apparatus useful for making the oven sheath of FIGS. 15 and 16 according to another embodiment of the present invention and FIG. 19 is a schematic perspective view of an apparatus useful for making the oven sheath of FIGS. 15 and 16 according to yet another embodiment of the present invention.

Referring to FIGS. 15 and 16, the oven sheath which is suitably made of polyethylene comprises a front wall 101 and a rear wall 102. Referring to FIG. 15, the oven sheath has heat seal 103 along the side edges thereof and referring to FIGv 16, the oven sheath has weld seals 104 along the side edges thereof. The top and bottom edges of the oven sheath are open. The oven sheath includes an elongated metal member such as a metal wire 111 or metal foil, which is held in place on the front wall 101 in a similar manner as in FIG. 1. At the side edges of the sheath, semicircular holes 113 have been punched out with the removal of the metal member 111.

Referring to FIG. 17, the oven sheath of FIG. 16 is produced by withdrawing a pair of sheets from supply rolls 121 and passing the superimposed sheets along a path over tensioning rolls 126 to a pair of nip rolls 130. Metal wire 111 is fed from rolls 133 onto the upper sheet 120. After the superimposed sheets 120 have left the last tensioning roll 26, wires 111 are attached to the upper sheet 120 at six points by the tech niques described with respect to FIGS. 6 and 7. The su perimposed sheets 120 are further cut longitudinally of their path by knives 134 to provide for the simultaneous production of three oven sheaths. Holes 142 are punched out of the sheets 120 by punches 141 at the points where each wire 111 intersects the portion of the sheets 120 which are to be cut by the hot knife 131 thus avoiding damage to the knife 131 during the cutting operation. The sheets 120 are subsequently cut transversely of their path on passage through the nip rolls 130 by the hot knife 131 to produce a weld seal on each side edge of the oven sheath.

Referring to FIG. 18, the sheath of FIG. 16 is produced by folding the longitudinal edges of a sheet 120 of polyethylene withdrawn from a supply roll 121 upwardly and inwardly until their longitudinal edges contact at 135. The superimposed layers of the sheet 120 are then passed along a path over the tensioning rolls 127 to nip rolls 130. Subsequent to the passage of the superimposed layers of the sheet 120 over the last tensioning roll 126, the superimposed layers are longitudinally cut by a knife 134 at the abutment of the longitudinal edges and also along the longitudinal folds as to simultaneously produce a pair of oven sheaths. As in the process of FIG. 17, metal wire 111 is fed from supply reels 133 to the upper layer of the superimposed layers according to the techniques of FIGS. 6 and 7 and holes 142 are punched in the superimposed layers by punches 141 at points where each wire lll intersects the portion of the superimposed layers which are to be cut by the hot knife 131 thus avoiding damage to the knife 13! during the cutting operation.

The superimposed layers of the sheet 120 are then cut transversely of their path on passage through the nip rolls 130 by the hot knife 131 to produce a weld seal on each side edge of the sheets.

Referring to FIG. 19, the oven sheath of FIG. 16 is formed by folding in half a sheet 120 withdrawn from supply roll 121 by means of the folder 123 to provide equal superimposed layers. These layers then pass along a path through tensioning rolls I26 to a pair of nip rolls 130. During passage along the path and after leaving the last tensioning roll 126, the folded edge of the sheet 120 is slit by a knife 134. As in FIG. 17, metal wire 11] is fed from supply reels 133 to the superimposed layers according to the techniques of FIGS. 6

and 7 and holes 142 are punched in the superimposed layers by punches 141 at points where each wire lll intersects the portion of the superimposed layers which are cut by the hot knife 131 thus avoiding damage to the knife 13! during the cutting operation. The superimposed layers are then cut transversely of their path on passage through the nip rolls 130 by the hot knife 131 to produce a weld seal on each side edge of the oven sheath.

To form the oven sheath of FIG. I5, there is used instead of a hot knife 13] in the apparatus of FIGS. 17 to 19 to produce a weld seal, a pair of hot bars and a cold knife to effect cutting and sealing of the side edges in a similar manner as in FIG. I3.

I claim:

I. In a recloseable bag formed of flexible sheet material comprising at least a front wall and a rear wall at least one edge of each of said front and rear walls being sealed together, and said bag including in the surface of at least one wall thereof at least one elongate deformable member extending in a direction transverse to the common direction of said edges which are sealed together. wherein the improvement comprises that an end of said elongate member stops short of a line formed by extending the common direction of said edges which are sealed together, and none of said flexible sheet material lies in an area between said end of said deformable member and said line, said area being located between the ends of said edges which are sealed together, and said deformable member does not extend into said area.

2. A bag as claimed in claim 1 in which the front and rear walls are sealed together at two opposite side edges thereof.

3. A bag as claimed in claim 2 in which said elongate member extends in a direction transversely of the side edges adjacent a top end of the bag.

4. A bag as claimed in claim 3 in which the front wall and the rear wall are sealed together adjacent the top thereof. said elongate member providing for subse' quent repeated closure of the bag after rupture ofa seal adjacent the top thereof. and the absence of flexible sheet between said end and said line material providing for communication between the interior of the bag and the outside atmosphere.

5. A bag as claimed in claim 4 which has a scalable open bottom.

6. A bag as claimed in claim 4 which has a sealed bottom.

7. A bag as claimed in claim 4 including a reinforced header attached to the top thereof.

8. A bag as claimed in claim 1 in which the front and rear walls are sealed together at least at the bottom edge thereof, said elongate member extending transversely of top and bottom edges of the bag.

9. A bag as claimed in claim 1 in which the elongate member is attached by means of an adhesive tape.

10. A bag as claimed in claim I formed of a thermoplastic sheet material the seals being heat seals.

11. A bag as claimed in claim 1 which is formed of a thermoplastic sheet material the seals being heat seals, the elongate member being attached by a heat sealed thermoplastic tape.

I2. A bag as claimed in claim 1 which is formed of a thermoplastic sheet material the seals being heat seals, the elongate member being attached in a heat sealed gusset in said wall.

13. A bag as claimed in claim 1 in which the elongate deformable member is a metal wire.

14. In a recloseable bag formed of a flexible sheet material comprising a front wall and a rear wall sealed together at or adjacent two opposite side edges thereof and unsealed at the top and bottom edges thereof said bag including in a wall thereof an elongate deformable member extending transversely of each of said side edges and extending adjacent each unsealed edge to provide for closure of said bag. the improvement in which the ends of each elongate member are spaced from said sealed side edges of the bag, without sheet material between the ends of the member and a line formed by extending the direction of the side edges of the bag.

15. A bag as claimed in claim 14 in which the elongate member is a metal foil.

Claims

1. In a recloseable bag formed of flexible sheet material comprising at least a front wall and a rear wall at least one edge of each of said front and rear walls being sealed together, and said bag including in the surface of at least one wall thereof at least one elongate deformable member extending in a direction transverse to the common direction of said edges which are sealed together, wherein the improvement comprises that an end of said elongate member stops short of a line formed by extending the common direction of said edges which are sealed together, and none of said flexible sheet material lies in an area between said end of said deformable member and said line, said area being located between the ends of said edges which are sealed together, and said deformable member does not extend into said area.

4. A bag as claimed in claim 3 in which the front wall and the rear wall are sealed together adjacent the top theReof, said elongate member providing for subsequent repeated closure of the bag after rupture of a seal adjacent the top thereof, and the absence of flexible sheet between said end and said line material providing for communication between the interior of the bag and the outside atmosphere.

5. A bag as claimed in claim 4 which has a sealable open bottom.

6. A bag as claimed in claim 4 which has a sealed bottom.

10. A bag as claimed in claim 1 formed of a thermoplastic sheet material the seals being heat seals.

12. A bag as claimed in claim 1 which is formed of a thermoplastic sheet material the seals being heat seals, the elongate member being attached in a heat sealed gusset in said wall.

14. In a recloseable bag formed of a flexible sheet material comprising a front wall and a rear wall sealed together at or adjacent two opposite side edges thereof and unsealed at the top and bottom edges thereof said bag including in a wall thereof an elongate deformable member extending transversely of each of said side edges and extending adjacent each unsealed edge to provide for closure of said bag, the improvement in which the ends of each elongate member are spaced from said sealed side edges of the bag, without sheet material between the ends of the member and a line formed by extending the direction of the side edges of the bag.

15. A bag as claimed in claim 14 in which the elongate member is a metal foil.