US2577386A - Bag forming machine - Google Patents

Description

D80 1951 J. G. VERGOBBI BAG FORMING MACHINE 4 Sheets-Sheet 1 Filed Aug. 14. 1946 INVENTOR. 6406;!

Dec. 4, 1951 J. G. VERGQBBI 2,577,386

' BAG FORMING MACHINE Filed Aug. 14. 1946 4 Sheets-Sheet 2 IN VEN TOR. fin l rg oo d/ dash-Q A-MQLJ Arrae/Yev Dec. 4, 1951 J. c. VERGOBBI 2,577,336

BAG FORMING MACHINE Filed Aug. 14. 1946 4 Sheets-Sheet 3 INVENTOR.

BYJOA a go/ kwmgczws LJLQ Dec. 4, 1951 J. G. VERGOBBI BAG FORMING MACHINE 4 Sheets-Sheet 4 Filed Aug. 14. 1946 Patented Dec. 4, 1951 e BAG FORMING MACHINE John G. Vergobbi, Quincy, Mass., assignor to Pneumatic Scale Corporation, Limited, Quincy, Mass, a corporation of Massachusetts Application August 14, 1946, Serial No. 690,368

This invention relates to a packaging machine and more particularly to a container forming machine.

In general the invention has for an object to provide a novel and efilcient container forming machine which among other uses may be embodied with advantage in a packaging machine for producing the inner liners for lined containers.

Another object of the invention is to provide a novel and improved container forming machine of the type provided with a mandrel or forming block and in which provision is made for opening a flat bag and transferring the same onto the forming block in a novel and efficient manner whereby to overcome difficulties formerly encountered during such operation.

- With these objects in view and such others as may hereinafter appear the invention consists in the packaging machine and in the various structures, arrangements and combinations of partshereinafter described and particularly defined in the claims at the end of this specification.

In the drawings illustrating the preferred form of the apparatus, Fig. 1 is a plan view of a packaging machine embodying the present invention; Fig. 2 is a side elevation of the machine shown in Fig. 1; Figs. 3 and 4 areend views in cross section taken on the lines 33 and 44- respectively of Fig. 2; and Fig. 5 is a perspective view of apparatus for opening and transferring a flat bag onto a collapsed mandrel.

- In general, the present invention contemplates theprovision of apparatus for the production of inner bags or liners adapted to be sealed for use in a container suitable for the packaging of dehydrated foods. In the preferred embodiment of the invention individual flat bags may be produced from a web of ba forming material comprising a heat sealable material such as the prodnot commercially obtainable in sheet form under the trade name Plyofilm. Provision is made for forming the bag forming material into a strip havingva closed top and open bottom and for sealing the strip transversely and along the iongitudinal bottom edge to form a series of connected bag sections. The strip may and preferably will be intermittently moved into position for effectingthe transverse and longitudinal sealin operations. v v p In the illustrated embodiment of the invention, provision is made for severing successive bag sections-adjacent one 'side of eachtransverse 9 Claims. (01. 93-18) on one side by the folded edge and heat sealed along two edges. Provision is also made for opening the flat bags thus formed by bag opening and transferring means arranged to engage opposed walls of the bag, and to separate the walls at the mouth of the bag sufficiently to enable the bag to be drawn over the forward end of a collapsed mandrel or forming block and then bodily transferring the bag onto the mandrel, the latter preferably forming part of a package making machine for wrapping a container about the bag thus disposed upon the mandrel. In the subsequent filling of the package the extended mouth portions of the rectangularly formed lining bag may be brought together face to face and sealed to provide a hermetically sealed container forming an eflicient package suitable for use in the packaging of dehydrated foods or the like.

. In the preferred embodiment of the invention the bag opening and transferring mechanism for transferring a flat bagonto a mandrel may comprise movable suction members engageable with opposed side walls of the flat bag, and said suction members are arranged to be spread apart to effect separation of the side walls and opening of the bag to permit the same to be transferred over the mandrel. Prior to the present invention difficulty has been encountered in opening a flat bag'in this manner because of the lack of an air vent leading into the interior of the bag between the contiguous side walls of the bag, the displacement of the air from the interior of the ba during its manufacture tending to hold the side walls together. In accordance with one feature of the present invention provision is made for forming a flat bag open at one end and provided with an unsealed portion forming a vent at the other end of the bag,

saidvent being subsequently sealed at a succeeding station of operation. Provision is further made for directing a stream of air through said vent into the bag and between the side walls thereof prior to and during the ba opening operation whereby to permit the bag to be successfully opened preparatory to transferring the same onto thejmandrel.

Referring now to the drawings, [0 represents a web of bag forming material such as Plyofilm. As herein shown, the web may be withdrawn 'froma roll I2 thereof by suitable unwinding mechanism indicated generally at 14, and. in the formation of the bag the web being withdrawn is arranged to pass through shaping mechanism. comprising. a generally .V-shaped sealtoform' individual open mputhbags closed flared forming member l6, and between idle and to project a stream of air through said.

opening and into the foremost bag section which is about to be transferred onto a mandrer, an

air pipe I9 is arranged to extendyertically, as

being suitably journaled in bearing members 50 attached to the machine frame.

Provision is made for continuously unwinding the Web H] of bag forming material from the roll i2 thereof at a rate sufficient to permit the strip to be intermittently advanced by the feed rollers 39, 32, and as herein shown, the web I is continuously withdrawn by cooperating; rollers 52, 5'4arranged' to bedrive'n through connections from the shaft lfi including a sprocket 56, chain 58, sprocket E0 and cooperating gears 62 and 64,

an idler sprocket 65 being provided to permit illustrated, between the side wall's of. the strip" at a point adjacent the forming member, [Bimtilf it reaches a medial point between the upper and lower edges of the strip and thereafter the pipespace between the walls of, the strip;anditheepipe terminates ata point adjacent the endmost bag section, as will be hereinafter more ,fully described. In orderto accommodatetheair-pipe [9. between the strip during the forming and sealing operations, eachiroller I8, is formed in twosections spaced apart vertically to straddle the pipe [9, and, the transverse sealing portions 22,, 24 are likewise spaced apart to. leave an unsealed. portion atthe point where thepipe-passes between the walls of the strip.

The cooperating sealing members. 22; 24 are preferably, of an L-shape arranged to formsuccessive transverse and longitudinal seals whereby to form a series of equally spaced bagrsec tions, and as herein shown' the strip of ba forming material is intermittently drawn past the shaping and sealing mechanisms by a pair of driven rolls 30,32; which are likewise formed in two, sections-sp'acedapart vertically to straddle the pipe [9' and to continue thevent opening-in the transverse portion of the strip. Therollers 3G, 32 are arrangedto advance the stripone-b'ag section each cycle of operation and toxpresent the endmost bag section into operativerel'atlon to. a, cutter indicated at 341 arranged tosever the endr'n'ost. bag section from" the strip along a line, disposed, immediately; to the rear of each transverse seal wherebythe latter forms the; end orbottom closure for" the endmost' bag section and. the, severed portion adjacentithereto" forms the openin forthe mouth ofithejsucceeding'b'ag section, thus, forming individual bags, open at the forward end toform the mbuth'of the'b'ag andjhaving an unsealed medial portion forming a vent opening at the trailing end or bottom of the bag. Thereaftenthe mouthportions of sue"- cessive individual. bags are opened by bag'opening and transferring. means, indicated generally at 36 arranged, to draw. the bagoveran'expansible mandrel 38, the latter preferablyform ing, one of; a:.plurality thereof carried by ariin termittentlyi rotatable spider 40" of the carton forming machine 41'. As illustrated Figs. 1 and 5 the pipe [9 terminates immediatelyirffront ofthe cutter 34, V

Referring now to Fig. 1', the presentjbag'making and transferring section of the packaging ma.- chine may be driveninlany convenientmanner, and as herein shown'pthrough; connections from a shaft42 forming a part of the carton'formirig section ofz heilmachine. herein shownpa bevel gear 44 fasten the shaft GfmeshesWitha bevel 'gear 16 fast on a camshaft? the latter tightening of ,the chain 58. The cooperating roller. 52r: is.arr'anged"to be rotated through frictional engagement with the roller 54, and as herein illustrated, the roller 52 is carried by bearing-rrnembers lifiw-hich are mounted for vertical adjustment in a bracket 10, the proper adjustment being effected by hand screws 12. In order to take up the slack in the web effected by the continuous feeding of" the material while-- the strip is atrest-i the web If? is arranged t "pass underaweighted roller 14 which latter is 'aX ially" movable in: vertically slotted brackets 16. in order to permit-a quick release of'the-upper reed roller 52 the'lattermay be rotatably mounted upon an eccentric shaft 53 provided with a handl'e' 55 fast onone" thereof whereby'upon rnanu'ar rocking of the eccentric shaft the roller is raised wardly awayfrom"the roller 54 to facilitate-the insertion ofa new Web of fiiltl iall b'iitilllefl the rolls;

I'ri' the operation of the niachir'ie-theweld'theh passes over the-flared -\"/'-sha ped" rormer: f6 and between the vertical rollers l8; ZI- arrangedtd sha e andfold the Web; as above described; to form a strip hav-ing aclosed' tdp'eiid open bot tom. The strip-advancing roller's 30, 32 aIs-best shown in Fig; 4; arearrarig'e'd tobe-interrhit-' tently rotat'ed' to advance"the-strip orie bag lengtli each cycle of operationthr'ough co'r'inectio'ns Clildilflg a cam- 18 fast -o'n the shaft 4'8"arrarig'ed' to reciprocate a" rack 81? connected to a canelever 82 which carries aroller 84 cooperating with the'cam 18';- The rack BDE'isar-i ang edtOcooperate with a piniorr BB rQtatabIy-inOunted on a shaft BB a'hd has formed integrally therewith a pawr carrier disk- QU prciV-ided withpa'wls 92 arranged to engage a ratchet- 94 fas't' o'n one-end of the shaft 88% as hereinfshown, the" rack may and preferablytwill; be held in meshi'ng' relation-- with its pinion bypa -gllidebl'a icket 9 6 rocking'ly mounted on the shaftWEZ 'Iheother end-of the shaft fis' 'is pro'vijdedjwith a bevel gear 5, 8 which mes e with a'be'vel gear l'OO fast 'on the en'd o'f the vertical shaft' I 02'- carrying the advancingroller 3'21: Each-advancingroller 3115 32 is pro Vi'de'd with an int'erme riinggear I04, I05;- as shown",- to drivethe rol-le'rsgi ri unison:

I'r'r theiope'ration of theLstrip advancing mech anis'm WhGIlft'hE' rack" 80 rocked upwardly through the connectionsabove described the pinion 86% and: pawl carrier 90} rotate idly-on the shaft 88, the'palwle 92 slipping overthef teeth of the ratchet 794': dilrihg "this stroke which com prises: the: idle period" the intermittent a'dvancementof the-strip;- Gofiverselmwh'en' the rack so isrocked downwardlyg t e-teem of has ratchet ar'ei engaged bythe pawls 92 to rotate theshaft 88 and effectro'tation the-advancing rollers 35, 32, as above described.

Previews-1 made for'separatingfthe idler rcll- V i3 2 6 alldilth Stlfilf advancin rollers taper a stripp'f Hag fbrming material o be' Y5 ihserted th'erehe-tweerfiwhewanewroll thereof 1sstarted through the machine and; as herein shown, one of each pair of rollers I8 and 30 is rotatably mounted upon an eccentric shaft I08. The upper end of each shaft I08 is provided with a handle I I fast thereon and the handles are preferably connected as by a link II2 to permit simultaneous release of each roller from its cooperating roller. In operation, when a handle is rocked clockwise, viewing Fig. 1, the eccentric shafts are rocked in their hearings to effect rocking of the rollers I8, 30 away from their co-, operating rollers.

From the description thus far it will be observed that the web of heat sealable bag forming material is folded longitudinally, andintermittently advanced through the machine, the advancing rollers 30, 32 being driven at a rate such as to effect advancement of the strip a distance of one bag length each cycle of operation. Referring now to Figs. 2 and 3, provision is made for heat sealing the bag forming material along predetermined zones during each rest period of the strip comprising a'transverse zone H4 and a marginal longitudinal zone II6, the transverse section having a vent opening therein as described. Thus a complete bag section is formed during each cycle of operation to provide a series of connected bag sections.

As best shown in Fig. 3 one of the L-shaped sealing members comprising the heated member 24 is stationary, being mounted upon and insulated from a bracket I I8 attached to the machine frame, the vertical leg of the L being open at its medial portion, as shown, to provide clearance for the pipe I0 and to form a vent between the sealed portions above and below the pipe. The cooperating sealing member 22, as herein shown, is formed in upper and lower sections corresponding to the spaced portions of the stationary sealing member 24 and is attached to a supporting bracket I formed integrally with an arm I22 pivotally mounted at I24 and which isarranged to be rocked to move the member 22 into and out of engagement with the heated member 24. Rocking movement of the arm I22 is effected through connections from a barrel cam I26 fast on the cam shaft 48 and include a ,cam lever I28 fast ona rocker shaft I30 and carrying a cooperating roller I32. The rocker shaft I30 which is journaled in brackets I34 attached to the machine frame is provided with toggle linkage including an arm I36 fast on the shaft I30 and a connecting arm I38 pivotally connected to the arm I22. A spring I40 attached to the toggle farm I36 holds the roller I32 against its cam to effect breaking of the toggle linkage to the left, viewing Fig. 3 when permitted by the cam I26 and thus rocking the member 22 away from the member 24 to permit the strip to be advanced during the strip advancing cycle of operation. When the strip comes to rest the cam I 26effects extension of the toggle linkage wherebyto provide substantial pressure of the member 22 against its cooperating heat sealing member 24 to seal the strip as above described. Thesealing member 22 may be adjustably mounted upon its supporting bracket I20 by screws I42 and In the preferred embodiment of the invention. provision is made for assuring that the sealing members 22, 24 are in their open or separated position when the machine is stopped and for this purpose, as herein shown, a solenoid operated hook I50 is arranged to engage a pin I52 carried by an arm I54 fast on the rocker shaft I 30 to rock the latter in a clockwise direction, viewing Fig. 3, when the clutch is disengaged to stop the machine. As herein illustrated, the hook I50 is .pivotally carried by a rockingly mounted arm I56, depending from the underside of the machine frame, and which is connected by a link I58 to the armature I 60 of a solenoid I62. As shown in Fig. 3, the solenoid I62 is arranged to be energized upon closing of a switch I 64 in a circuit I66 when a clutch handle I68 is moved to disengage the clutch I10 provided on the drive shaft 42. In operation, when the switch is closed to energize the solenoid I62, the hook I50 is moved to the left viewing Fig. 3 to rock the shaft I30 thus breaking the toggle linkage to the right to cause the presser member 22 to be moved away from its cooperating member 24 during the time the machine is at rest.

4 Referring now to Figs. 4 and 5, the cutting mechanism 34 for severing the endmost bag section from the strip at each cycle of operation comprises a pair of shear blades I12, I14 carried by a horizontal rod I16 extending longitudinally beneath the end of the strip and the collapsible mandrel 38, the rod I16 comprising a guide forming a part of the transferring mechanism to be hereinafter described. One of the shear blades I12 is stationary, being provided with a depending extension I18 attached to a rectangular guide bar I extending from the transferring mechanism. The movable blade I14 is arranged to be rocked through connections from a cam I82 fast on the cam shaft 48 and, as herein shown, the connections include a cooperating roller I84 carried by a lever I86 fast on a rocker shaft I88, a lever I90 also fast on the shaft I88, and a link I 02 connecting the lever I90 to an arm I94 to which the shear blade I14 is attached. In the operation of the device the cutter is arranged to sever the endmost bag section at a point immediately to the rear of a transverse seal while the strip is at rest to form an open mouth bag section having a vent opening at the opposite end as described. A coil spring I96 on the shaft I16, held under compression by a collar I98, is provided to press the blades together in operative engagement.

Simultaneously with the severing operation or preferably immediately prior thereto the mouth portion of the endmost bag section is engaged by the bag opening and transferring mechanism 36 1 which is arranged to support the bag during and after severance thereof. Thereupon, the bag is carried forward and, as the bag is advanced, the mouth portion is opened up and the opened bag is drawn over the expansible mandrel 38 to be shaped into rectangular form in the subsequent operation of the packaging machine. The bag opening and supporting means is then returned to its initial position to grasp the mouth portion of the next succeeding bag section which has been advanced during the transferring operation. As above described, the air pipe I9 terminates 'just before it reaches the cutting mechanism 34, and in operation is arranged to blow a continuous stream of air through the vent opening and into the endmost bag section to separate the-walls thereof preparatory to transferring thebag onto miter-e1. The blower pipe 18 may be connected to I any usual or preferred sourceof air "such as an air-p'ump, not shown, and may be'co'n- 'trolle'd-by-a valve 21.

its best shown Fig. S-fthebag supporting and-'- transfer-r-ing -mechan ism preferably comprises suction means includin'g a 'pluralityof pairsof opposed nozzles 2 5:0 extending "from pipes 202 which are supported in arms 1294 fast upon studs 206- rockingly mounted in --a slide member 208. The lower-ends of pipes- 202 are connected by a flexible conduit -2 i 0 and vacuum is'suppliedtothe nozzles through a flexibl'e con-- duit 2 i2 connected to a 'valve 214' attached to themachine-irame. A conduit 216 leading from the *underside of the valve "21 may b'e'connected to any usual or preferred'sour'ce of vacuum-such as-a vacuum pump, not shown. The var/e214 is arranged to be operated by a cam 2'l8-cooperating with a roller 220 carried by 'one'arm 8" pipe and als'o' because of the-engagement o'f the vertical-1y spacedportions of the rollers- 3., 32 with the upper-and lower portionsof the strip andthe stream of air being blown through the endrnost -xba'g 'sectio'n through "the pipe 1 9'. Thus, when-the bag i'sgrasped by the su'ction nozzles 200 a'bove 'an'd loelowthe longitudinal medial 22 2 of a bell crank pivotally mounted at "224. a

The other arm 225 of the bell crank is connected bye. link 22% to the valve operating arm 228;

As herein shown,'the slidemember 268 is slidingly rnounted for reciprocation upon the guide rod I16 and is maintained in a vertical'position by. the provision of a grooved portion 209 on the underside thereof arranged to embrace the recjtangular bar l8iias clearly'shown-inFig. 5. The lowerend f each rocker stud 266 is provided with an arm- 23 0carrying-ro1lers 2-32 arranged to cooperate with a stationary cam piece 234. The ends'of the arms'Z'SQ are connected by a spring 236 t0 hold the rollers against the cam. With this construction it will be seen't-hat when the slide is advanced the rollers 232 "following the stationary cam piece 234 cause the opposed suction nozzles 200 to be separated to effect opening --of the mouth portion as described.

As illustrated herein, the slide memberE-OB is reciprocated through connections from a cam '240 including a cooperating cam roller 2'42 'carried by a lever 2 4 i fast on arocker shaft 246, lever 248'also fast on the'sha'ft 2 16, and which is connected by a link- 2 50 to-a lever 252 pivoted 'at' 254, and a link 2% connecting thelever 252 to theslide member. In the operation of the device when the slide member 2fi8 is-in its fully retracted position the suction'nozzl'es Zfifiengage opposed sides of the endmost bagsectio'n and the vacuum-valve Ht-is then opened to efiect adherence of-thebag to the-nozzles. Upon severance ofthe bag section the bag is'transferred to the mandrel as above described and 'when the slide member is in its fully extended position the vacuum -valvefl is closed to-release the 'ba'g from'the nozzles whereupon the slide member is returned to its retracted'position.

In the operation of the 'machine prior to and during the transferring operation a "continuous stream of air may be directed through th'e vent opening and into the endin'ost bag section to permit separation thereof by" the suction members 2B0 in 'engagement with the outer surfaces or the sidewalls. In practice, the-longitudinal medial portions of the-sidewalls of the bag: are bulged out slightly in passing'over the pipe l e-to provide a continuous vent in-alignment'with the unsealed portion of the transverse-seal and communicating with theopen'mouth portionof the bag. In passing between and *beyoridthe feed rollers 30, 3'2 and'bey'ond' the end offthe'pipe l9, this bulged out relationship betweenthe wallsis 'piontinued dueito the relatively fixed or "set' posiportion the b'ulged out relationship is maintained to continue the vent opening; Thereafter the cuttin -mechanism 34 15 operated to sever the endmo'st bag section, and upon rocking of the blade' l'|4 out of cutting positionythe blower pipe 1 9 may "continue to direct air into the vent opening- 23 du'rin'gthe -tran'sfer ofthe bag onto the collapsed man'drel, as above described. It will be understood that after the severing operation the vent-opening '23 may remain partially open duetdthe relatively set "position of the side wal1safter passing over the pipe" [9 and which is'maintaine'd in 'such position'by the suction-members -2110. Thusyin one aspect of the invention, th'e -vent opening alone in communi- 'CatiOIbWi-th the atmosphere may be sufficient to permit separation of the side Walls by the suction memb'ers during thetransferring operation. However,-inpraotioe it is preferred to continue thestreamor air in the direction of the vent opening after severance of th'e -endmostbag section from the stripto assure separation of the side walls. While itis preferred to providea continuous stream of air, in'pra'ctice, the valve 2i may-be controlled bya cam if desired todiscontinue the stream of air during the severing operation. I

Upon transference of the bag onto the collapsed mandrel' '38 the latter is expanded during subsequentmovement of the intermittently operated-"spider "40 of the carton forming machine tothe nextstation of operation-to square up the hat bagintorectangular form, and, when the mandrel comes to rest at this station provision may be rriade-ior sealing the vent opening 23 in the endof the bag. As herein shown, this may be ao'complished'by a pair of presser members 300; -302 =oneof which may be heated. The

ip'resser m'embers 3B0; 3ii'2 'are-carri'ed by arms 304,

306 respectively mounted on vertical shafts 3G8, 3L0 connected to, be rocked simultaneously in opposed directions by cooperating gears "3 l 2, 3-! 4. The arms -304,3Ii6 'are arranged to be 'rocked'into and'out of pressing engagement with the extended unsealed portion 'ofthe bottom seam by '-a-cam 3 i5 -'fast' on an extended portion of the cam shaft 48 and through connections including a bell crank, one-arm'iHfi-o'f Which carries'a cam roller -3|="8 cooperating with the cam, and the other arm 320 of which is connected by a link 7 322 to anarm 3'24 fas'ton the vertical shaft 308.

From the description above it will be seen that the presentbag -forming apparatus is adapted to produce a flat-bag offheatfsealable material such as Plyofilm"provided withface to face marginal seam's -wherebyg-to produce a bag which maybe 'usedto advantage inthe production of an her.- metically sealedi container for dehydrated foods 'o'rthe lik'e. It wil1=a1sobeobserved'that thepresent bag opening and transferring mechanism may beuse'dwith advantage for supportingand 'aoni o f-"thabag-material aiter passingpventhe to following claims.

Having thus described the invention, what is claimed is: 1. In a bag forming mechanism, in combination, an expansible mandrel, container form- ,ing means comprising means for forming a flat bag having an open mouth portion and provided with an unsealed portion forminga vent in the opposite end of the bag, said container forming means being disposed with relation to the mandrel to support the formed bag in substantial alignment with said mandrel, bag opening means cooperating with said bag forming means andarranged to engage opposed side walls of the flat bag to spread them apart, means for drawing the opened bag onto the mandrel, and means for directing a stream of air through said vent and between the side walls of the bag to facilitate separation thereof during the opening operation.

2. In a packaging machine, incombination, an "expansible mandrel, means for supportinga flat bag in alignment with said mandrel, said bag having an open mouth portion and provided'with an unsealed portion forming a vent in the opposite end of the bag, means for opening and transferring the bag onto said mandrel including means arranged to engage opposed side walls of the flat bag to spread them apart, means for directing a stream of air through said vent and between the side walls of the bag to permit separation thereof during the opening operation, and means for moving said bag engaging means to effect opening of the bag and for drawing the bag onto said expansible mandrel.

3. In a packaging machine, in combination, an expansible mandrel, means for supporting a fiat bag in alignment with said mandrel, said bag having an open mouth portion and provided with an unsealed portion forming a vent in the opposite end of the bag, means for opening and transferring the bag onto said mandrel including suction means arranged to engage opposed side walls of the flat bag to spread them apart, means for directing a stream of air through said vent and between the side walls of the bag to permit separation thereof during the opening operation, and means for moving said bag engaging means to effect opening of the bag and for drawing the bag onto said expansible mandrel and means for sealing said vent while the bag is disposed on said mandrel.

4. In a bag forming machine, in combination, bag forming means comprising means for folding a web of bag forming material longitudinally to form a U-shaped strip, means for sealing the strip transversely at spaced intervals and along the open marginal edges of said strip to form a series of connected bag sections, said sealing means being constructed and arranged to incompletely seal the strip transversely to provide an unsealed portion forming a vent therein, means for intermittently advancing the strip a distance of one bag length each cycle of operation, a cutter for severing successive endmost bag sections to form individual flat bags each having an open mouth portion and provided with an unsealed portion forming a vent opening in the opposite end thereof, bag opening means cooperating with said bag forming means and arranged to engage opposed side walls of the flat bag to spread them apart, andmeans comprising an air pipe disposed longitudinally" of and within the U-shaped strip and having its end terminating adjacent said cutter for directing a stream of air through said vent and between the side walls of the endmost bag 10 'to' facilitate separation thereof during th'e'op'ening operation, said air "pipe being of a sufiicient size to provide a bulge in the side walls of the bag. 5. In a packaging machine, in combination, bag forming means comprising means for folding a web of bag forming material longitudinally to form a U-shaped strip, means for sealing the strip transversely at spaced intervals and along the open marginal edges of said strip to form a series of connected bag sections each having an unsealed portion forming a vent in said transversely sealed portions, means for intermittentlyadvancing the strip a distance of one bag length each cycle of operation, a cutter for severing successive endmost bag sections to form individual flat bags each having an open-mouth portion and provided with an unsealed portion forming a vent opening in the opposite end'thereof, bag opening means an air pipe passing'between the folds of said strip and through said unsealed portions for directing a stream of airthrough said vent and between the side walls of the bag to facilitate separation thereof during the opening operation.

6. In a machine of the character described, in combination, ba'g' forming means comprising means for folding a web of bag forming material longitudinally to form a U-shaped strip, an air pipe passing between the folds of said strip, feed rollers for intermittently advancing the strip a distance of one bag length each cycle of opera-. tion and arranged to straddle said air pipe, sealing means comprising a pair of L-shaped cooperating presser members arranged to provide a transverse seal at spaced intervals and a longitudinal marginal seal, the vertical leg of said L being spaced to straddle said pipe and to provide an unsealed portion in said transverse seal, a cutter for severing successive endmost bag sections to form individualflat bags each having an open mouth portion and provided with an unsealed portion forming a vent in the opposite end thereof, bag opening means cooperating with said bag forming means and arranged to engage opposed side walls of the fiat bag to spread them apart, said air pipe terminating adjacent said cutter and being arranged to direct a stream of air through said vent and between the side walls of the bag to permit separation thereof during the opening operation.

7. In a machine of the character described, in combination, bag forming means comprising means for folding a web of bag forming material longitudinally to form a U-shaped strip, an air pipe passing between the folds of said strip, feed rollers for intermittently advancing the strip a distance of one bag length each cycle of operation and arranged to straddle said air pipe, sealing means comprising a pair of L-shaped cooperating presser members arranged to provide a transverse seal at spaced intervals and a longitudinal marginal seal, the vertical leg of said L being spaced to straddle said pipe and to provide an unsealed portion in said transverse seal, a cutter for severing successive endmost bag sections to form individual flat bags each having an open mouth portion and provided with an unsealed portion forming a vent in the opposite end thereof, bag opening means cooperating with said bag forming means-including suction members engageable with opposed side walls of the fiat bag at points above and below the line of communication between said vent and the mouth of thewbagprior toitheaseveringioperation means for moving said: suction members -to,;,effeot.openingof the? bag, said-:air pipe beingiarrangedi to direct? a "stream: of air through sa-id went? and: between :the sidewalls of thebaaprioratoand duringthe-openingioperation;

8.. Imamachine. of: thecharacter:descrlbed,.-in combination, means for supporting a flat-bag having, an open mouthgportiomat one'end-otthe ,bag and providedwith an: interrupted transverse sealto:providelan-unsealed portion forming avent .in-theopposite endmf the bag, bag opening means ,arranged'to engagewopposed side walls of the flat :bag; to spread themapart, means for directing a streamSofa-1rthrough; said ventand between the sidewallsofzthebagtoiacilitate separation thereof during ,theopening operatiomian expansible mandrel uponwhich the;openedibagisdrawn: and meansifor subsequently sealing said ventiopening while the bag is dis-posed on the mandrel;

:9. In a .bag forming'machine, inoombination, container: form-ingmeans-:comprismg means for forming a fiatbagandmeans for effecting; an :in-

complete transversewsealat one-end-thereof to provide 1 a. flat bagihaving an open mouth- Eportion at one end of the.:bag;andlranaunsealed portion forming -a vent in the opposite "end' of the bag, bagropening :means mooperating with :said bag forming means arranged toengage opposed side walls? of the flat bag-"t cs spread themapart, and

means including a longitudinally extended-elevmentof. less Width than aaflat-bag disposed in a position v. to :extend :between the side walls of, the

,flat bag during the ,formingoperation and; means holdingv said-walls .togetherlon oppositesides of said element for shaping portionsoiitheside walls of theibag toprovide a relatively narrow distended passageway between tbezmouth, portion; oi the .bag and, saidunsealedportionwherebyto admit ,air between: the. side .walls to. ,-facl1itate separation thereof during the bagopening operation.

7 JOHN ,G. VERGOBBI.

REFERENCES CITED The. ifollowing;;references rare iOf" record:v .in th file ofthis "patent:

UNITED STATES PA'IENTS Vergobbi Aug, 10,..1948

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