US2449272A - Means for vacuum sealing flexible packages - Google Patents

Description

Sept 14, 1948.. sQHQ BERCH A 7 2,449,272

MEANS FOR VACUUM SEALING FI JEXIBLE PACKAGES Filed Jan. 22, 1944 5 Sheets-Sheet 1.

[NVEN TOR; 529M064 h. 51sec! Sept. 14, 1948. s. H. BERCH MEANS FOR VACUUM SEALING FLEXIBLE PACKAGES 5 Sheets-Sheet 2 Filed Jan. 22, 1944 P 4, 1948. s. H. BERCH 2,449,272.

1 MEANS FOR VACUUM SEALING FLEXIBLE PACKAGES Fild Jan. 22, 1944 -5 Sheebs-Sheet :s

jYVE/YTOK JFIMULL H. BERCH.

S. H. BERCH Sept. 14, 1948.

5 Sheets-Sheet 4 Filed Jan. 22, 1944 Patented Sept. 14, 1948 MEAN SFORVACUUM SEALING FIz'EXIBLE "PACKAGES .isamne'i H1: Berch, "Beverly Hi11s, Calif-. assignor to The Flexible Vacuum Container Corporation, Los Angeles, Calif., a corporation f.. Nevada ApphcationJanuary 22,1944; Serial No. 519,372

9 :IuClaim. 1

1 This invention relates to flexible p e 'machinery, and particularly pertains to a means "for vacuum sealing flexible packages.

" The present "application is a continuation in part of my co-pending application entit1edVac-- uum packaging'machine',Serial No. 450,297; filed by me in the United States Patent Office July 9, 1942; now Patent -No. 2,428,192, issued Septembar-30, 1947. -Thisvacuumpackaging machine is designed to-handle flexible containers which are constructedwith' an inner liner, the faces of which unite to form a vacuum-tight :seal" under "the action of-heat and pressure; Themachine is provided with a magazine carrying emptyi ipackages formed from a blank bymaking'a reentrant fold therein-and which packages are held in the "magazine in a fiat'condition and are'automatically removed therefrom, shaped t'o form a'container of final configuration and are then p'laced within individual carrying inolds, in which m'olds they are successively carried toa filling station and to a" final sealing stationj 'The'present invention is'concerned with the construction: and operation of the'sealing apparatus atsaid final sealing station, In order to obtain Volume pro--- &

duction from the machine it is'. desirable to arrange the molds in groups"extendingtransversely of the machineand to move'a group of molds through themachinein" step by-stepoperation, and to simultaneously "deposit thshaped containers' within the molds; to thereafter fill. the containers," and then vacuumize and se'al the con- 'tainers at the final 'sealingstation." Since'the 1 containers are often filled-with'finely divided materials, and since there may be a slight varia-- tion in' the thickness of the-"walls of the container at the point of forming the seam, it isnecessary to provide means which will insure that the contents of the packagewill not'be drawn between the abutting faces tobe 'seamedgand to insure that proper pressure and heat shall be'-applied individually to the containers of agro-up at the 'final seaming station; "'whereby -the' individua1 sealedpackageswill each be vacuurn tight'." It is the principal object of the present-invention, therefore, to provide a method'and apparatus for vacuum sealing packagesywhich =i'nc1udesasealwing head at which a group of-individualfiexible packages may-be 'subjected -to'vacuumaction without undue disturbance'of the contents of the packagaand to insure further that the mouth portion ofthe packages will be' gripped; and that said packages are subjected to -a-vacuum action -and then to pressure and heat-in-Ja manner to act upon each packag'e iri' dividuallyg whereby a (CL-93w6) 2 1 uniform vacuum sealing action: of.- eachtpackage 1 will takeplace.

:The' present: invention contemplates the" provision of carrier runits'fitted with 'oneruoromore 5 .inoldpockets intowhichi'fi'exible containers are positioned, and which units ma'yim'ove i to r'egister with a vacuum head actingwtol subjectthe-icontainer and its contents to progressively:increasing vacuum action, and to. engage themo'u'th of the container in a manner toapply heat and pressure to the side walls" thereof inaformin'g a.

vacuum-tight seal between said walls and a durable, strong 1 sealed seam; andmeans for "progressively subjecting the packages to a suction action prior to sealing" the-'packages' under 'con- 'ditions ofvacuum.

.The.invention is illustratedtbywayof example in the accompanying drawingsin which:

Figure 1 is a view in ,perspectiveshowingithe empty container with 'whichtheipresent invention is concerned.

Fig; 2. is a. view in perspective showing 1 the formed package ready-for filling.

(5 .Fig. 3 is a view. in.perspective."showingithe finally filled and sealed package.

'Fig. 4 is a View. in side :elevation showingthe complete packaging machine..andcindicating. the

, position of the sealing head.

Fig.5 is an enlarged view in transverse section showing thesealing head. with parts hrokenlaway for sake of convenience. V

Fig. .6, isa View in plan showing thezsealing head and. the relationship of the operating. cyl- .inders. i

. vFig. -.7 is:an enlarged fragmentary viewdnsecl tionand elevation showingthe operating: memhers of-one ofthe sealing headunits.

Fig.- 8-15 a View in- :centra-L- vertical-section 4E0 through-the sealing. head. structure-as seen on the line 9-8. ofFig. 'lzandindicates.thearelationship of the parts of thesealing-head;structure prior to a sealing operation.

Fig. 9 is a View in central "vertical sectionisim- 4.5 ilar to Fig. 8; showing theztpartsoathewsealing head in operation. .1 Fig. 10 is afragmentary viewxirrplan withiparts in section. aswseen'; gene-rallyon the line.--l-0I ll of Fig. .7 and showsrthe' operating. mechanism for the sealingiblades.

Fig; 11 is a: view: imverticalssection: andfeleva- ,tion as :seen:.on. theiline I l a! Ifyofu Fig.;.1 01 show- .ing the::mechanism:for folding thekbladeszinto r tzandoutlotsealin'g. position.

msFigy 12 is-"a view-imtransversa sectionalthrough here shown as being made of sheet material folded upon itself to form front and back wall sections II and I2. The inner face of the sheet of material carries a lamina which may be of thermoplastic material or other suitable flexible material, preferably having qualities which insure that it will not transmit oxygen when a collapsible package made therefrom is sealed in vacuum and its walls are subjected to exterior atmospheric pressure. Such material should also have the characteristic that when heat and pressure are applied to abutting sheets thereof they will be'united to form a vacuum-tight seam. Such seams are indicated at I 3 and M in Fig. 1 of the drawing. It is to be understood that due tothe construction of the sheetmaterial forming the package the walls of the package are impervious to air, other gases, and moisture.

The container formed as shown in Fig. l of the drawings, is to be shaped, filled with a commodity, and then vacuum sealed by the apparatus with which the present invention is concerned.

. The machine for handling the container It and with which the present invention is concerned is generally indicated in; Fig. 4 of the drawings. Here it will be seen that a base I 5 is provided, at

one end .of which is a magazine station A ineluding a magazine structure [6 within which the containers iii are stored and from which they may be drawn by the mechanism associated therewith. Adjacent to the magazine structure is a filling unit B. This includes a hopper l1 and filling spouts l8. Adjacent to the filling station '5 is a package spreading and creasing station C, and beyond this station is the sealing station; D, with which the present invention is particularly concerned.

The base structure l5 houses parallel horizontal shafts l9 and 20. The shaft l9 carries sprockets-2| and the shaft 25 carries sprockets 22. Around these sprockets are led conveyor chains 23 and secured transversely of the conveyor chains and arranged at spaced intervals therealong are mold units 24. These units carry a"plurality of molds 25, as particularly indicated in Fig. 5 of the drawings, each of the molds being intended to receive one of the containers I!) after it has been shaped to assume the configuration shown in Fig. 2 of the drawings. When in this I shape it will be noted that the seams l3 and I4 "extend longitudinally of the narrow sides 25 and 21 of the container, and that relatively wide sides-28 and 29 are provided. The container when shaped and deposited into the pocket of a mold 25 has a square closed end, while the depth 1 v. of the mold is such as to insure that the walls forming the open mouth of the container will pro- Ii ject above the top of the molds, as particularly disclosed in Figs. 8 and 9 of the drawings.

The. mold units 24 comprise a plurality of the molds. 25 and these molds are disposed at right angles to the path of travel of the chains 23 upon which they are. carried. The conveyor chains thus move themolds successively from the magazine station A to the filling station 13 and then to the spreading and creasing station 0 and the sealing station D. The intermittent drive mechanism for the sprockets 22 and 23 will not be described, although it is understood that power is applied to main drive shaft 30 and that suitable intermittent driving mechanism transmits driving force to the shaft 20 carrying the sprockets 22. The details of construction of the apparatus shown at stations A, B and Care of no concern to the present case, and attention will therefore be directed to the construction of the sealing station D shown particularly in Figs. 5 to 11 of the drawings.

Referring particularly to Fig. 5, it will be seen that a mold unit 24 consists of a plurality of molds 25 which are spaced from each other along a plate M. The plate 3| is secured to the sprocket chains 23 by fastening means 32. Supporting rails 33 are disposed beneath the plate 3| and are spaced longitudinally thereof to maintain the plate in a rigid horizontal position during the sealing operation. Mounted upon the upper faces of the sides of the base ii are vertical standards 34. These standards consist of a block 35 secured to the base l5 by cap screws 35. The block 35 supports a vertical cylindrical shaft 31 upon which a sealing head 38 reciprocates vertically. The sealing head 38, as particularly shown in Figs. 8 and 9, includes a top'plate 39, opposite side plates 40 and 4|, and end plates 42. These form an inverted trough-like structure which may be lowered on the standards 34 to a position to form a sealed space over the mouth of the molds 25 in a mold unit registering with the sealing station. The lower edges of the side plates 45 and 4! and the end plates 42 are formed with channels 43 which are grooved to receive a packing strip 44. The packing strip 44 is intended to move into positive contact with the upper face of the plate 3| of a mold unit. This packing strip may be made of neoprene or other suitable deformable material which will form an air-tight seal between the plate 3| and the edges of the head structure 38.

The sealing head 38 reciprocates vertically upon the standards 34 as moved by pitman rods 45. The upper ends of these rods are pivotally connected to the sealing head by pins 46. The lower ends of the rods are pivotally connected by pins 4! to oscillating levers 48 mounted upon a pivot shaft 49. The oscillating levers 48 each carry cam rollers 5| at a point intermediate their ends. These rollers rest upon an eccentric cam 52 mounted upon a shaft 53. The shaft carries a gear 54 in mesh with a gear 55. This gear is mounted upon a shaft 56 which also carries a gear 51. The gear 51 is in mesh with a pinion 58 mounted upon the drive shaft 30. 7 It is to be understood that the intermittent drive of the sprocket chains 23 is such that when a mold unit 24 is in register with the sealing station D and is disposed directly beneath the sealing head 38 the drive chain and the mold units will stand stationary while the sealing head goes through a cycle of operation to be lowered onto a mold unit and V to be lifted therefrom.

Mounted upon the top plate 39 of the head 38 is a plurality of vertical brackets 59. These brackets are formed by parallel arms 60 and BI which are integral with a base plate 62 and are secured by suitable fastening means 63 to the plate 39. Carried at the upper ends of the brackets are cylinders 64. These cylinders are open at their lower ends and arethreaded at their upper endsto i receive I a cylinder head*-65. "Ih'e cylinder heads 65 are-each formedwitha-central threaded opening -66 to-receive an extension of a manifold pipe 61; This pipe is fitted at one end witha flexibleconnection 68 leading to a source of "air under'pressure not shownin the drawings; Reciprocably mounted within the cylinder 64 is a piston 69 carried upon" a-piston rod The piston rod it extends downwardly through a guide bore inthebas'e 62 of the bracket -59 and'projects into the sealing head structure i 38." Suitable packing 1 i2 is disposed aroundthe piston'rodto' prevent aleakage of air into or from the sealing head. Mounted" upon the'pistonrodsiiiand extending between the arms Wand (ii of the bracket 59 is a cross-head '13, at the opposite ends of which springs M are secured The upper ends or these springs are securedto across-head mounted upon-thetop of each'of the cylinder heads '65. It' is intended thatthe delivery of air under pressure to the cylinders through the manifold 57 will cause the pistons 69 inallof the cylinders 64 to move down simultaneously, and-when'pressure is relieved for the springs "i l to retract the pistons upwardly within the cylinders. A suitable timing valve it is: interposed between the source of fluid under pressure and the connection 68 so that the piston 69 will be reciprocated "only when th -sealing head and a mold unit are in proper registered position with each othen as shown in Figs. 8 and!) ofthe drawings. I

Also "mounted upon the top plate til' oi' the sealing headtii are valve structures 11, i8 and F91 Theseare shown'particularly' inFigs'. 12, 13 and 145; respectively. These-valves are provided to carry out the vacuum sealing operation of the machine in accordance with*:the method set forth in Letters Patent No. 1 2,241,943 and issued 'towmeMay 13; 1941. In this patent it wasrex- 'pla'ined that prior to the sealingofaapaokage or the type here indicated bythe numeral.iilfthe openipackage was subjected" to suction faction, whereby a vacuum would be created'within the headi 38, and that thereafter the package would be'sseale'dn When this operation. is completed 'accordihgrsto the invention of the Iaforem'entioned patent. the interior of the sealing s-head 238 and the molds ofthe mold-unit aredisconne'cte-d from the suctionrpumpiand a connection to the' atmosphere is made, whereby the interior of thezstructure: will: .ber subjected to .atmospheric. pressure and the individual packages will becompacted and 'shaped to conform to the mold, asindicated in of the drawings.

In&view of the fact that the containers Il'i'are usedtoa great extent in packaging finely'divide-d lmateria'lgasuch as. coffee; millnwand thalike; it has b'een'foundthat if the contents of thexpackage are subjected to a violent'suction;actionrthe lighter-"material in the 'packageis liablei tobe lifted from"the' m'ass and drawn betweenrrthe abutting faces which" are to comprise the sealed area of the mouth of the finished container. For that reasonit is desirablefirst to subject the contents within the-package to a relatively low degree*' of suction and 'to' thereafter subject it to 'increasedsuction; so that a high vacuum will be attained without disturbing the contents oftthe package violently; In order to accomplish this the is valve: Ti "m -closed? and 1 the a valve 78wis openedz The"*valve' -'18 causes the high d'egree of vacuum-to-becreated Within -the sealing hea'd and the mold unit. When the desired mriod' of suction action "has been concluded the valves" Tl 'and 18"ar'e both placed in: a closed position'and thevalVe-IB is opened. This establishes== communication between the sealing" head and the atmosphere. In order to accomplish this action of'the valves in synchronism' a cam shaft is 4 mounted in suitable bearings iii emu driven through a fie'xible drive 82-from timing gears, whereby'the valves 11; 18 "and 'I-il will operate in sequence: The valve 'l'l'isfitted with abracket 83 which carries a pivot '84 upon which a rocker arm 85 is pivotallymounted. The lower end of this arm ridesovera cam 86 'upon' the shaft flll and the uppcr end or the arm bears against a valve-plunger 87 by'which the valve 11 is opened. 'Suitable'spring means forming a part ofthe valve structure restore "the plunger" 81 to its original position:and'cl'ose the valve. The valvestructure 'i'fi iricludes a bracket fifi carrying a pivot pin 89 upon which arocker arm Si) is plvotally mounted. The lower end of this arm rides over a cam 9!. The upper end of ';the arm'- bears against a valve plunger 921by which the valve i8 may be opened, it being understoodthat suitable means within the valve structure closes the valve and restores theiplunger 92 toits original position. The valve 75! includes abracket 93 carrying a pivot pin iii-upon which a rocker :arm 95 is pivotally mounted; The lower end :of 'this rocker arm bears against a camilt carriedupon the cam shaft to." The upper end of the armlcears against a valve plunger s1 by Whichthe valve iii maybeopened, afterwhich it is closedby suitable spring means .within the :valvevstrncture. It will baunderstood that thevalvesr'il, i8 and? 9 openand close in sequence.-

Mounted within the sealing :head. 33ers sep arateiunits for folding and sealingtheamouths of the individualfille'd'packages after they have been vacuumiz'ed.' Attention is directed tothe fact-that while the pistons 69 and their rods iii are simultaneously moveddcy action of the-air under press-ure'idelivered through. the manifold 61 and 'thatwthese rods operate various folding andsealingmechanisms, it is desirable that each of the folding and sealing mechanisms shall adapt itself to the individual package upon which it acts without reference to :the other packageszbeing folded and "sealed, thusinsuringithat each package will be properly folded andseale'd regardless of variation inits wall thickness. This .structureis particularly'shown in Figs. 7 to 11 of the drawings.

iBy referencetoFigs; 8 and 9=of thedrawings it will. be seen that the individual molds 25 project a-distanceabove thelupper surface 0f the anold plate 3i andthus beyondthalower-edges of. the wallshof the sealing head 38. Mounted within the sealingihead, to beidisposed suponopposits 1 sides :of the upwardly projecting portion ofthamolds- Zip-when the head is in its lowermost-position, are==iolding and. sealing'arms 98 and 99m These arms :arezcarried uponq parallel shaft-s aim] and iilinwhich extend longitudinally ofithe'sealing head and are supported at inter vals along thelength of the sealing'head by bearing brackets ifi2.- The shafts iilil and illi are disposedzin "a horizontal plane parallel to the plane ofthelcwersedge of the sealing head-38 :and spaced a .desire'd'idistanc'e. thereabove, a1-

thoughipo'sitioned to occupy a plane. lower ithan l-thataof: theiupperzedge of the-molds @Zmwhemthe sealing head is in position over the molds. "The arm 99 is intended to fold down over the top of a mold 25 and to engage the upwardly projecting portion Ia of the container I0 to fold the upwardly projecting portion of the side wall of the package downwardly and at right angles to the filled portion of the package. The filled level of material within the package occupies substantially the same plane as the plane of the upper lip of a mold. The arm 99 includes a flat blade I03 which is formed integral with supporting portions I04 disposed at right angles to the plane of the blade. The supporting portions terminate in bosses I05 disposed adjacent to opposite ends of the blade I03 and through which shaft IOI extends. Attention is directed to the fact that shafts IOI are provided, one for each of the molds 25, and that while the ends of the shaft are supported in the bearing brackets I02 with the shafts in longitudinal alignment, the shafts are individually rotatable. The free end of the folding blade I03 is offset and has a relatively thin end portion forming a face I05 and a shoulder I0'I. The end of the blade 99 is of a length to terminate along the vertical median line of the filled package I0 within a mold 25.

The folding arm as is formed with portions I03 connected to bosses I 09 through which shafts I00 extend. The portions I 08 are formed with blades H0. The free end of the blade H0 has an enlarged portion forming an inclined seat for a sealing pad II I. This pad is preferably made of rubber and extends longitudinally of the blade to form a face against which the sealing operation takes place. The enlarged end of the blade H0 has an oifset portion H2 which overlies the narrow extension at the end of blade I03 when the blades I03 and H0 assume a position in substantially the same horizontal plane over the end of a complementary mold 25.

The shafts I00 and lill carry gear segments H3 and H4, respectively. These segments are in mesh with gears H5 and H0, respectively, which are carried upon shafts II] and H8, respectively, secured to the brackets I02. The gears H5 and H6 are in constant mesh, and as shown in Fig. 11 of the drawings the gear H5 is fitted with a crank pin I I9 receiving a shackle I20. The opposite end of the shackle M0 is pivotally connected to a lever arm I2! by a pin I22. The lever arm is mounted upon a shaft I23. This shaft carries a radially extending screw I24 which projects through a circumferentially extending slot I 25 in the boss of the lever I2I. Due to this arrangement the shaft I23 will have limited rotation with relation to the lever arm I2I, as represented by the space between end shoulders I20 and I2! of the slot I25. The shaft I23 is journaled within contiguous brackets I02 of the sealing head and is disposed within a plane above the shafts II! and H8 and offset from the central median line of the sealing head. The shaft I23 also supports a sealing bar structure I28. This structure is formed with a base plate I29 carrying arms I30. The arms I39 are formed with bosses I3I through which the shaft I23 extends. Set screws are provided to secure the arms against rotation on the shaft. A pressure bar I33 is secured to the face of the portion I29 and is formed to receive an electric heating element I34. A pressure face I35 is formed on the bar I33 so that when the bar is swung downwardly in a sealing operation it will be aligned with the face of the pad III and will thus co- .operate. with therpad to pressuthe side wallsof the mouth portion of the container I0; as shown in Fig. 9 of the drawings. The portion I29 of the sealing bar unit I28 is provided with a pin I30 to receive shackles I31. The opposite ends of the shackles I31 are connected to the lower ends of the piston rods I0 by pins I38. Thus, as the piston rods 10 reciprocate they will oscillate the sealing bar units I28 around the axis of shaft I23. It will be seen that-when the shaft I23 rotates it will impart rotation to the gears H5 and H6. The rotation of the shaft I23 to the gears H5 and H6 is imparted through a helical spring I39 which is wound around the shaft I23 and is secured to the shaft at one end by a collar I40. The opposite end of the'spring is secured to the boss of the lever arm I2I, thus making it possible-for a flexible drive to be establishedso that after the folding blades I03 and H0 have swung to their folding position, as shownin Fig. 9, the'sealing bar structure I08 may continue to swing toward its sealing position and exert a desired pressure upon the seam to be formed without restriction from the folding mechanism. Attention is directed to the fact that at opposite ends of the blades II 0 downwardlyextending fingers I4I occur. These pass down along opposite sides of the mold, as indicated by dotted lines in Fig. 9.

In operation of the present invention flexible containers of the general character shown in Fig. 1 of the drawings are placed within the hopper I6 of the magazine unit A. They are then automatically withdrawn and shaped, as shown in Fig. 2 of the drawings, during which time they are deposited within molds 25 of a mold unit 24. The drive shaft 30 acts through a suitable intermittent drive mechanism to impart a step-by.- step motion to the sprocket chains 23 and successively move a mold unit with a set of containers I0 to the filling hopper B and the spreading and stretching station C, and then in register with the sealing head 38 at the sealing station D. When the mold unit 24 is directly beneath the sealing head, as shown in Fig. 4 of the drawings, the cam 52 will be driven to lower the cam arm 48 and to thus act through the side arms 45 to lower the sealing head 38 into a position of rest upon the plate 3| of the mold unit.

This position is particularly shown in Figs. 8 and 9 of the drawings. Here it will be seen that the packing strips 44 form a seal between the vertical walls of the sealing head 38 and the plate 3I. It is to be understood that the pressure exerted against the packing strips 44 is suflicient to hold the sealing head vacuum-tight, so that when suction is exerted from a suitable suction-pump and through the valves 11 and 18 the filled containers within the mold unit will be subjected to suction action so that a vacuum will be drawn in the containers and the molds within which they r are placed. After the sealing head 38 has been swing the sealing bar structure downwardly and to rotate the shaft I23 upon which it is mounted. Simultaneously a torque force will be imparted through the spring I39 to swing the lever arm I2I downwardly and to impart rotation to gear I I5 through the shackle I20 and the pin II.9. In

view of the fact that the gears .I I5. and .I I6 are in constantzmesh', .thegearl I will-rotate counterclockwise; and the'egean H6 will rotate clockwise: The? gear; segments :II 3. and I It will then be row tated to swing the folding arms 98 and"99.:around the axes of the shafts 400 and II. The blade I03 of arm 99 will. precede theblade I II] of the arm 98 so that the enlarged end' portion of blade III will overlap the narrow. end portion of blade I I33. As these blades swing from the: position shown in Fig. 9 to the position shownin Fig. 10 the portion Illa of the mouth of a container I ll will be folded togethere and then the portion II2 of the-blade l lilhvillfifoldia length .IDIII'OVBIifihzfflCG I06: bflthe blade. -:I 031-:h1nview of. the..length .z'of the original portions. IIIatthere -Will..be.. a surplus amount of the packageawallwhich would then'fold upwardly andilieagainst thev outer .face ofathe pressurepad III .As thetpiston. 69 continues to move'idownwardlyiit may do. sowhile rotating. the shaft "I 23 and while permitting the lever arm I2I to stand stationary due to the provision for a lost motion between the screw I25 on the shaft I23 and the ends I26 and I2! of the slot I25 in the lever arm I2I. Thus. while holding the arms 98 and 99 in their folding position the heat sealing bar I33 may be swung downwardly to bring its face I 35 against the end portion of the container walls which now occur between the outer face of the pressure pad III and the face I35 of the sealing bar structure. Any desired pressure is then exerted directly through the piston rod Ill to the sealing bar structure I29 to force and hold the bar I33 against the side of the surplus end of the package. A clamping action will take place between the pressure pad III and the face I35 of the sealing bar, and since the sealing bar is being heated by the heating element I34 it will be recognized that since the inner surfaces of the walls of the package II) are covered with thermoplastic material or the like a heat seal will be formed between these walls, and in actual practice this heat seal has proved to be vacuum-tight. It is to be understood that at a desired interval after the sealing head 38 has moved to a sealing position with relation to the plate 3I of the mold unit and before the time the sealing bar I33 is forcefully pressed toward the pad I II to form the complete seal, the desired suction action takes place to create a condition of vacuum within the container I0 and around the container I0 within the mold 25 which it occupies. This operation is produced by first opening the valve 11 to permit a low negative pressure to be created by suction through the valve 11. After this has taken place the valve 11 may be closed and the valve I8 opened. This causes a high negative pressure to be created within the sealing head 38 and within and around the package. The heat sealing bar I33 is then forced firmly against the walls of the portion [0c of the container to produce the seal while the entire sealing head and mold unit are maintained under high negative pressure. When the heat sealing interval has been completed, valves 11 and I8 are both closed and valve 19 is opened to atmosphere. This permits air under atmospheric pressure to enter the sealing head 38 and to pass into the space between the sealed package and its mold 25, with the result that instantly the material within the package is compacted and the package is given permanent form and a shape agreeing with the configuration of the mold.

Attention is directed to the fact that when the folding arms 98 and 99 have moved to the position shown in Fig. 9 a point III) on the blade III] will assume a position agreeing with the faces I 06 and I01, of, the blade: I I13. 3 This causes the length-of theapackage walls, indicated-,atwlllc, to-be folded 8.13:2 an; acute; an le-to the length of zthegp cka walrindicated: at Iflb, with: 5119311681115; that ,-the suction action-;will-- evacuate; air I from; within :the packagalil; butwdue-to thefoldwill prevent small particles dust from, :within 'the,-package ;l II :to be;.drawn.between; the two surfacesywhich. are to be :23 ointedi a in lthe: rh'eat sealin'g operatiom, *zThe valves, sass previously'r;explained;:operatez-inv see quence: as: controlled; by .rthe rotation; of the- .-oam shaft; Bil-randithe camszllfipflI;::and%96.;r I I :Atten'tian is. directed. to. ithetifactz thatusincei :the sets of folding;- arms:.i93- and '99 which. areiprovided to act'upon.theZfiexiblewcontainers in eachzofithe molds will: beiagiven yieldable pressurezas =.;.they move toltheir foldedpositions, and that ithefplies sure bar "I 28 1 will thereafter .impose...a. positive pressure upon-the portion Beef thexcontainer III, this is due to the fact that a spring I39 is interposed between the positively rotated shaft I 23 and the operating lever IZI for the gears I I! and H8. Thus, the folding arms 98 and 99 will fold down from the position shown in Fig. 8 to the position shown in Fig. 9, and thereafter while they are yieldably held the piston 69 provided for each of the molds 25 willcontinue t move downwardly, exerting pressure upon the sealing bar I28, so that a sealing action will take place between the pad III carried by the folding arm 98 and the face I35 of the sealing bar as the piston moves to the end of its power stroke. When this operation has been completed the springs I4 will retract the piston 69 and swing the sealing bar I28 from the position indicated in Fig. 9 to the position indicated in Fig, 8 and the folding arms 98 and 33 will swing from their commonly aligned position, as shown in Fig. 9, to the position shown in Fig. 8.

It will thus be seen that the method and means here disclosed insures that a filled flexible package will be subjected to suction action in a manner to prevent disturbance of the contents of the package, and that the mouth of the flexible package will be sealed vacuum-tight while an operation takes place to shape the package into fixed final form, all of which method is performed automatically by the apparatus here disclosed.

While I have shown the preferred form of apparatus by which my method of vacuum sealing flexible packages is performed, and have indicated the preferred steps of this method, it is to be understood that various changes in the combination, construction and arrangement of the parts of the apparatus and variations in the steps of the method may be made by those skilled in the art without departing from the spirit of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

Means for shaping and vacuum sealing filled flexible containers, which includes a mold within which a filled container is positioned and which mold agrees substantially with the final configuration of the sealed package desired, a sealing head adapted to assume a sealed position with relation to the mold and whereby a vacuumtight chamber will be formed including said head and the mold, a pair of blades mounted within the head adapted to assume positions at opposite sides of the flexible unfilled portion of the container projecting above the mouth of the mold, pivotal mountings for said blades whereby the blades may swing to positions in a common 6 plane normal to the top of the package being 11 sealed, the free edges of said blades engaging opposite side walls of the mouth 01 the flexible container, whereby said side walls will be moved together substantially along the median line of the package, said free blade edges overlapping when lying in the same plane to fold the free portion of said side walls substantially in a plane parallel to that assumed by the blades, a sealing bar adapted to move with relation to said blades when they have assumed a common plane to fold the outer end of the container walls in a reverse direction from the original fold and at an acute angle thereto, means for heating said sealing bar, means for moving said folding blades and the sealing bar in synchronism to fold the mouth of the package and thereafter seal the same by the exertion of heat and pressure by the sealing bar, and suction means associated with the vacuumtight vchamber whereby the interior and exterior of thepackage will be subjected to suction action and after which the sealin bar will cooperate with a folding blade to heat seal the mouth of the package.

' SAMUEL H. BERCH.

REFERENCES CITED The following references are of record in the file of this patent:

Berch Mar. 24, 1942

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