US3524298A - Automatic packaging apparatus - Google Patents

Description

J. A. HAMILTON AUTOMATIC PACKAGING APPARATUS Original Filed Feb. 9, 1966 Aug. 18,- 1970 9 Sheets-Sheet 1 INVENTOR J0 Z J1. Ham 51 6-012 ATTOR Aug. 1970 J. A. HAMILTON AUTOMATIC PACKAGING APPARATUS 9 Sheets-Sheet 2 Original Filed Feb. 9, 1966 owl I 1970 J. A. HAMILTON 3,524,298

AUTOMATIC PACKAGING APPARATUS Original Filed Feb. 9, 1966 9 Sheets-Sheet 5 [ELM $919M Aug. 18, 1970 J. A. HAMILTON 9 Sheets-Sheet 4.

Original Filed Feb. 9, 1965 Aug. 18, 1970 J. A. HAMILTON AUTOMATIC PACKAGING APPARATUS 9 sheets-sheet 5 Original Filed Feb. 9, 1966 Aug. 18, N70 J. A. HAMILTON AUTOMATIC PACKAGING APPARATUS 9 Sheets-Sheet 6 Original Filed Feb. 9, 1965 I ITZMVWwWmW? w I T o 3, 1970 j J. A. HAMILTON 3,524,298

AUTOMATIC PACKAGING APPARATUS Original Filed Feb. 9, 1966 9 Sheets-Sheet '7 T 9A 10A rq 11A /ZZ /Z{ a 22 v VI/I Aug. 18, 1970 J. A. HAMILTON 3,524,298

AUTOMATIC PACKAGING APPARATUS Original Filed Feb. 9, 196 9 Sheets-Sheet 8 Aug. 18, 1970 J. A. HAMILTON AUTOMATIC PACKAGING APPARATUS 9 Sheets-Sheet 9 Original Filed Feb. 9, 1965 NNN @NN QNN l L b 4, QNN l 6 [h m1 llll 3N mww 3w .5 E

United States Patent 0."

3,524,298 AUTOMATIC PACKAGING APPARATUS Joel A. Hamilton, Englewood, N.J., assignor to Mahatfy and Harder Engineering Company, Totowa, NJ. Continuation of application Ser. No. 526,081, Feb. 9, 1966. This application July 1, 1969, Ser. No. 840,131 Int. Cl. B65b 31/04, 47/10 U.S. CI. 53-22 46 Claims ABSTRACT OF THE DISCLOSURE An automatic packaging machine for making hermet ically sealed and evacuated packages from two continuous webs of flexible plastic packaging material, the machine comprising a pair of side-by-side chains driven intermittently around a closed path having upper and lower reaches, there being mounted on the chains a series of spaced clips adapted to grip the side edges of the packaging material to carry it along said path past a series of operating stations, one of said stations including vacuum forming means to draw one web into a series of cups, another operating station having a sealing die arranged to receive filled cups and to seal the margins thereof to the second web of packaging material, the sealing die also including evacuating means for withdrawing air from the sealed package through a slit which is closed olf after evacuation has been completed.

This application is a continuation of my copending application Ser. No. 526,081, filed Feb. 9, 1966, now abandoned. The invention relates to packaging apparatus. More particularly, this invention relates to such apparatus which is automatically operable to form evacuated packages, eg from roll stock of flexible film.

Various machines for making packages automatically have been proposed, and some have proven successful commercially, for example the machine described in US. Pat. 3,125,839. Such machines have been especially suited for applications where there are long packaging runs of the same or similar type of product. However, there are a number of other potential applications where it is de sired to package a variety of diiferent types of products, or products of different sizes. The machines available heretofore have not been adequately adaptable for such use, primarily because of the effect and time required to alter the machine for making packages of different size, and also because of the relatively high cost of the machines.

Accordingly, it is a general object of this invention to provide packaging apparatus, methods and techniques which are superior to those available heretofore. A more specific object is to provide automatic package-forming apparatus especially adapted to make packages of different sizes without requiring extensive change-over alternations. Still another object of this invention is to provide such apparatus which is economical to construct and operate. Other objects, aspects and advantages of the invention will in part be pointed out in, and in part apparent from, the following description, considered together with the accompanying drawings, in which:

FIG. 1 is a perspective view of a complete packaging machine incorporating the present invention;

FIG. 2 is a vertical longitudinal section of FIG. 1 to show the interrelationship of the main operating elements of the machine;

FIG. 3 is a cross-section taken along line 33 of FIG. 2, providing an end view of the forming station;

FIG. 4 is a detail section showing the clip arrangement for gripping the film;

FIG. 5 is a plan view of the clips shown in FIG. 4;

3,524,298 Patented Aug. 18, 1970 FIG. 6 is an enlarged view based on a portion of FIG. 2, to show the clips as they move around the sprocket;

FIG. 7 is a vertical section taken along line 77 of FIG. 3 to show the internal construction of the heating and forming elements;

FIG. 8 is a vertical longitudinal section showing the internal arrangement at the package finishing station;

FIGS. 9, 10 and 11 are successive plan views of one package cup showing the sealing sequence;

FIGS. 9A, 10A and 11A are detail sections showing the respective sealing elements in the positions corresponding to the sealing operations of FIGS. 9, l0 and 11;

FIG. 12 is a perspective View of the sealing die;

FIG. 13 is a perspective view of the base for the sealing die of FIG. 12, arranged as an exploded view with FIG. 12 to show the interrelationship of these two parts;

FIG. 14 is a plan view of the machine, particularly showing the adjustable frame supports and omitting certain other details;

FIG. 15 is a detail elevation taken at line 1515 of FIG. 2 and showing certain aspects of the longitudinal adjustment mechanism;

FIG. 16 is a detail vertical section taken along line 1616 of FIG. 15; and

FIG. 17 is a detail horizontal section showing further aspects of the longitudinal adjustment mechanism.

Referring to FIGS. 1 and 2, the machine comprises an outer housing 20 within which are mounted two sets of rotatable sprockets 22 and 24 adapted to receive a pair of endless side-by-side chains 26 (see also FIG. 3) for movement around parallel paths. The left-hand sprockets 22 are rotated by a conventional electric motor drive (not shown) including a four-station Geneva gear to effect an intermittent indexing movement of the chains. Beneath the chains is a roll 28 of flexible plastic packaging film 30 to be formed by the machine into cup-like receptacles or pockets (referred to hereinafter as cups).

This film 30 is fed through powered draw-rolls 32 and a slack take-up dancer 34 to the lower horizontal reaches of the chains 26. Referring also to FIGS. 3, 4, and 5, these chains are positioned within conventional guides 27 and carry a series of film-holding elements comprising spring-loaded clips 36. These clips are adapted to grip the side edge portions of the film, as it leaves the top roll 35, and to carry this film around the path defined by the chains.

Each of the clips 36 includes an upper member formed as two side-by-side fingers 38 riveted solidly to the respective chain 26, and cooperating lower fingers 40 each pivotally secured to an upper finger at circular sections intermediate the ends. The inboard tip of the lower finger normally is pressed up against the adjacent tip of its upper finger by a two-section torsion spring 42 coiled around the pivot axis. The straight ends 44 of this spring engage the upper finger while an axial center element joining the two spring sections is looped around an car 41 of the lower finger. Thus the spring serves to apply the pressure for gripping the film, and also secures the lower finger to its upper finger.

At the place where the film 30 is to enter the clips 36, two rotatable discs 46 are positioned adjacent the two chains 28 respectively. These discs engage an outboard tab 48 of the lower fingers 40 of the clips 36 as these clips are shifted along the lower horizontal reaches of the chains. The indexing movement of the chains causes this tab to ride up to the top of the disc while the disc rotates. A back-up plate 47 is provided to prevent upward movement of the upper finger 38.

The indexing movement of the chains 26 carries the film 30 first to a forming station 50 on the lower horizontal reaches of the closed path of the chains. This station basically comprises two operating members 52 and 54 disposed above and below the film respectively. The upper member 52 is bolted to a cross-arm 56 which extends out through the main machine frames 58 where it is connected to a pair of longitudinal arms 59 pivotally mounted at 60 on respective longitudinal support bars 61. Pivotal movement of arms 59 produces a motion of member 52 basically in a vertical direction. The lower member 54 similarly is secured to a cross-arm 62 supported by two longitudinal arms 64 each pivoted at 66 on bar 61, thereby to produce basically vertical motion of member 54.

These two forming station members 52 and 54 are reciprocated synchronously in opposite directions by respective rods 68 and 70 connected to a rocker 72 which is actuated by a cam (not shown) rotated by the main machine drive motor. By these means, members 52 and 54 are moved towards and away from the film together, and the motion is timed so that the members engage the film while it is stopped during the dwell periods between indexing movements, in order to efiect certain package-forming operations to be described hereinbelow.

Referring now to FIG. 7, the upper forming station member 52 is a single unit comprising a heating plate 74 alongside of a vacuum-forming die 76 The lower member 54 also is a single unit, and comprises integral sections 78 and '80 arranged to cooperate with heating plate 74 and die 76 respectively to assure that the film is held in place properly during the heating and forming operations.

The heating plate 74 includes electrical heating rods 82 and is held by an overhead support 84 arranged in conventional manner to provide self-aligning action when plate 74 engages its cooperating section 78 of lower member 54, thereby to assure that the film 30 is pressed reasonably tightly against the rubber sealing edge 75 around the plate. After sealing has been effected, air is withdrawn from above the heating plate by a vacuum line 88, so as to draw the film lightly up against the plate. Heat thus is transferred to the film so as to soften the plastic material for the subsequent forming operation.

When the two forming station members 52 and 54 move apart, the heated portion 30a of film is indexed to the next position where this portion is engaged by vacuum-forming die 76 and its cooperating lower section 80 during the subsequent dwell period. This forming die comprises four vertical walls 90, and a conventional diefiller block 92 if desired, defining a die cavity having the shape of the package to be produced. When the upper member 52 has been moved down to operating position, the lower edges of the die walls are arranged to press lightly against the film so as to eifect a moderate seal therewith.

With the forming die 76 in operating position, air is withdrawn from the die cavity by a vacuum line 94 controlled by a vacuum valve (not shown). This valve is operated in synchronism with the chain indexing movement. Evacuation of the die cavity sucks the film up against the die to effect a tight seal therewith, and thereafter causes the film to be stretched up into the die by atmospheric pressure, so as to form a cup 100 suitable to receive the product to be packaged. The depth of the cup is controlled by the die-filler 92 secured to the top of the die, whereas the lateral dimensions are determined by the length and width of the die.

The cup 100 is formed with fiat marginal portions 104 extending around the cup mouth and in the plane of the mouth. The heat previously applied to the film portion 30a by plate 74 tends to soften the plastic in a known manner to accommodate the desired stretching of the film inboard of the margins 104.

The forming die 76 carries at its forward end a slitting knife 108 (see also FIG. 3) surrounded by a springloaded pressure bar 110 normally extending down around i the knife blade when the two members 52 and 54 are separated. When these members move together towards operating position, the right-hand edge of the lower section forces bar up to produce a high pressure grip on the film between these two parts. This pressure serves to hold the film in place while the knife 108 makes a slit 112 in the trailing margin of the preceding cup for the subsequent evacuation of the completed package as will be described. This pressure grip on the film margin also prevents the preceding cup from being drawn back into die 76 when this die is evacuated, and this desired result is aided by providing the lower member with a rubber pad 114 which presses against the film. The vacuum remains on in thedie 76 substantially until the end of the dwell period. This assures maximum cooling of the previously heated portion 30a and thereby minimizes spring-back of the stretched plastic.

The cups 100 are indexed along to the right (FIG. 2) and move around with sprockets 24 up to the top horizontal reaches of the chains 26. It may particularly be noted that the clips 36 are attached to the chain at such a distance from the chain centerline that the gap between adjacent clips is essentially unchanged as the clips go around the sprocket. This prevents tearing or distortion of the film.

Further indexing movement of the cups 100 carries them beneath a loading conveyor 116 from which products, such as stacks of luncheon meat 118, are placed in the cups. Thereafter the cups move beneath a roll 120 which applies a second web of plastic packaging film 122 over the cups. From there the cups move with top web 122 to a package finishing station generally indicated at 124 and including a second pair of oppositely reciprocable members 126 and 128. At this station, the loaded cups are sealed to the top web 122 to make complete packages. These packages then are evacuated and hermetically sealed, separated from one another into individual packages, and dropped onto a chute 130 on which they slide out of the machine.

The lower finishing station member 126 is carried by a cross-arm 117 supported by a pair of longitudinal arms 132 pivotally connected at their remote ends 134 to the main machine frames 58. The upper finishing station member 128 similarly is carried by a pair of arms 136 pivotally connected at their remote ends 138 to the main machine frames. Vertical rods 140 and 142 are connected to members 126 and 128 respectively, and extend downwardly to a conventional operating mechanism (not shown) arranged to reciprocate these rods in opposite vertical directions in synchronism with the indexing movement of the cups 100. Thus members 126 and 128 are moved towards each other to engage the plastic films 30 and 122 when the cups are stopped between indexing movements, and move away when the package finishing operations have been completed.

Referring also to FIG. '8, the lower finishing station member 126 includes a base 144 and a sealing die 146 comprising four vertical walls and a floor (e.g. a conventional die-filler block 147) defining a cavity 148 to receive the loaded cup 100. This cavity is the same size as the forming die 76, so that the cup fits snugly in the sealing die. The upper finishing station member 128 comprises a sealing clamp 150 arranged to press down against the die 146 to create an air-tight compartment and efii'ect a sealing around the mouth of the cup 100A then in the die.

Extending up into the sealing die cavity 148, just forward -(to the left, in the drawings) of the rear die wall 152, is an actuator support plate 153 integral with the base 144 and shaped to conform with the interior outline of the die cavity. Support plate 153 is formed with a vertical evacuation passageway 154 through which extends an elongate hollow gas stud 156, also fixed to the base 144. The top of this gas stud engages the trailing margin 104T of cup 100A, slightly outboard of the evacuation slit 112,

and holds this outboard margin approximately up against the top web 122.

At the lower end of passageway 154 there is a vacuum valve 158 which is opened (as by a cam-operated link controlled by the main machine drive) at the start of the dwell period to withdraw air from the interior of the cup 100A through slit *112, the air passing around a fluted stud support 160 in passageway 154. Other passages 162 connect the vacuum directly to the die cavity 148 under the plastic film, to assure that the pressure on the outside of the cup 100A is equalized with that inside the cup. Similarly the spaces 164 within the top clamp 150 are connected to the vacuum passageway 154 by a conduit 166 to maintain equal pressure on both sides of the top web 122. It may be noted that, during evacuation, the cup marginal portion '4T inboard of the slit 112 (i.e. towards the center of the cup) is drawn down slightly by the outflow of air so as to produce a somewhat enlarged evacuation opening and assure reasonably rapid evacuation.

While evacuation of cup 100A is proceeding, a serrated knife 168 in the forward wall 170 of the die 146 is shifted up to cut through both webs of plastic film, throughout the full width thereof, to free the next preceding package 100'P for removal when the finishing station members 126 and 128 subsequently move apart. This knife can be actuated by any conventional means, e.g. by overtravel of the cam-operated link used to open the vacuum valve 158. Reverting to FIG. 5, clips 36 are pro vided with uniformly spaced slots 37 into which the cutting knife passes, thereby permitting the Webs to be cut Without striking the clips. The spacing of these slots longitudinally is precisely proportioned to the amount of indexing movement of the clips, so as to assure that the knife always will pass into a slot and not Strike one of the clips.

Simultaneously with evacuation of cup 100A, a permanent seal is made between this cup and the top web 122 completely around the mouth of the cup. For this purpose, the top clamp 150' is provided with conventional heater rods 172 adapted to raise the temperature of the clamp surfaces to a level suitable for producing a permanent seal between the two plastic films. FIG. 9 shows the permanent seal line 174 extending around the entire periphery of the mouth of cup 100A. The rear (righthand in the drawings) transverse section of this seal line extends along the leading margin 104L of the following cup 100F. In other words, the seal effected by the die 146 and the heated clamp 150 extends not only around the cup 100A then being operated on, but also encompasses a part of the following cup IMF in the next position to the rear.

After the evacuation has been completed, the vacuum valve 158 is closed and a permanent seal is made around the evacuation slit 112. This seal is effected by a movable pressure bar 176 (FIG. 8) advantageously located within the sealing die 146. This bar surrounds the gas stud 156 and is mounted on actuator rods 177 (FIG. 10A) for sliding movement up to force the plastic film material against a recessed section 178 of the heated clamp 150. FIG. 10 shows the resulting oval seal 180 which surrounds the slit 112 in the trailing margin 104T of the cup 100A. It may particularly be noted that the movable bar 176 does not require heating elements because the sealing heat is provided by the clamp 150, thus simplifying the construction. Also, by locating the bar 176 intermediate the sides of the die (preferably on the machine center-line, as in this embodiment) and making the evacuation slit 112 correspondingly, problems of interference at the sides of the package are eliminated.

The pressure bar actuator rods 177 extend up through the actuator support plate 153 on both sides of the gas stud 156. These rods are reciprocated vertically in synchronism with the machine cycling, for example by any conventional means such as a cam-controlled link operated by the main machine motor. After the evacuation seal 180 has thus been completed, the vacuum passage 154 is vented to atmosphere through the usual vent valve (not shown) operated, for example, by overtravel of the cam-operated link used to actuate the pressure bar 176. Thereafter, the pressure bar is moved back down to its normal position.

In some applications, it may be desired to inject a small amount of inert gas into the package. In this case, before the pressure bar 176 is raised, the predetermined amount of gas is forced into the gas stud 156 by the usual gas line (not shown) at the lower end of the stud. This gas is emitted from the top of the stud through a lateral port 182 which directs the gas into the evacuation slit 112. Thereafter the evacuation slit will be closed off by the pressure bar 176 as previously described.

When the die 146 and clamp 150 separate at the end of the sealing operation, the completely evacuated and sealed package A is indexed to the next position (to the left (in the drawings). As shown in FIG. 11, when the die and clamp are reengaged, a further transverse seal line 184 is placed across the trailing margin 104T of this package 100A, just inboard of the evacuation slit 112 and overlapping the slit seal 180. Thus, when the knife 168 separates the two packages 100A and 100F (the latter now being in the sealing die), there will be no loss of vacuum.

Reverting to FIG. 10, it may be noted that the forward (left-hand) transverse section 174' of the seal line of the cup in the die cavity falls exactly on top of the transverse heat-seal line previously made by the rear edge 186 (FIG. 9A) of the clamp during the preceding cycle. Thus, when using this dimensional relationship, it may not be essential to provide heat sealing along that forward transverse seal line 174 and for some applica tions the corresponding sealing surface 188 (FIG. 11A) may be omitted while retaining the next adjacent seal surface 189. An important aspect, however, is that the clamp makes a permanent seal in any part of the peripheral seal line 174 where such permanent seal does not already exist when the cup is indexed into evacuating position.

Wherever a permanent seal line is to be made, the sealing surfaces of the die 146 (i.e. the top edges of the die walls) are provided with a resilient beading 149 of known composition, such as rubber, adapted to press the plastic film up against the mating sealing surfaces of the clamp 150. A layer of such material also is placed on the top of the pressure bar 178 for the same purpose.

One of the special features of the disclosed machine is its adaptability to making changes in package size. Generally, any change in length or width of the package requires substitution of new forming and sealing dies sized in correspondence to the new package size. This modification can readily be effected in a simple manner as a result of the novel machine design disclosed herein. This design has been based on the principle of reducing the number of packaging stations where operations must be performed on the film, thereby to minimize the number of elements which must be repositioned (longitudinally) when the length of the package is altered.

In this regard, the forming operations at station 50 are effected by two opposed mating members 52 and 54 which can readily 'be replaced with corresponding members of a different size. Moreover, these two members are arranged to be moved as a unit longitudinally to accommodate the change in package repeat dimension which occurs when the length of the package is altered. The package finishing operations at station 124 similarly are carried out by two opposed mating members 126 and 128 which are so arranged that they perform the bulk of the evacuating and sealing operations at a single package position. That is, at that single position the package is provided with a permanent seal around its entire peripheral seal line, evacuated, and then permanently sealed at the evacuation opening. The finishing station die and clamp which perform these functions are unitary, integral parts which can quickly be removed and replaced by similar units of different size.

Referring to FIGS. 12 and 13, the sealing die 146 may be removed from its base 144 simply by disengaging the hold-down bolts 190 and lifting the die up. Essentially, only the walls and floor defining the cavity 148 are removed, and the evacuation elements including the gas stud 156 with its associated operating parts remain as an integral portion of the base for use with a new die of the desired size. The base is provided with a gasket 145 to assure an air-tight seal when bolted together with any size die 146. Also, the base carries pivoted side arms 169 adapted to be pushed up to engage a knife actuator 168a to operate the knife 168, regardless of the distance between that knife and the rear (right-hand) edge of the sealing die then installed on the base.

Thus the die 146 is removable and replaceable in its entirety without the need for making dimensional adjustments between multiple parts. All of the peripheral sealing surfaces 190-198 are part of a single module, formed as a single casting, and only that module is replaced to provide an entirely new set of sealing surfaces. The mating top clamp 150 similarly is replaced as a unit merely by unbolting it from its support and substituting a new one matching the new die.

If the width of the package is changed, it is necessary to change the lateral spacing of the film clips 36 carried by the chains 26. Referring now to FIG. 14, this is accomplished by a crank 200 which directly rotates a first threaded shaft 202, and indirectly rotates a second threaded shaft 204 through the intermediary of a gear-chain connection 206. Screwed onto shafts 202 and 204 are hubs 208 carrying spaced vertical walls 210 to which the chain guides 27 (see FIG. 3) are attached. Thus, as the crank 200 is turned, the walls 210 move in or out to alter the spacing between the clips 36, as required for the new film width.

The movable walls 210 also include means for rotatably supporting the sprockets 22 and 24 for the chains 26. At the left-hand end of the machine, sprockets 22 are mounted on a splined shaft 212 which is rotated by a drive mechanism 214 connected to the main machine motor (not shown). To effect movement laterally of these sprockets 22 on the splined shaft, the walls 210 are provided with yokes 216 adapted to engage the opposite sides of the sprockets. The movable walls 210 also are secured to respective horizontal cover plates 211 (see FIG. 1) which are positioned out over the chains 26 and are shiftable with the Walls 210, back and forth under the horizontal surface of the main housing 20.

When the length of the package (i.e. the repeat dimension) is changed, it ordinarily will be necessary to change the longitudinal positioning of the forming die 76, in order to provide a whole number of package repeats between the edge of the forming die and the corresponding edge of the sealing die 146. Referring now to FIGS. 15l7, this adjustment is made by a mechanism arranged to move longitudinally the support bars 61 (see also FIG. 2) to which the forming station arms 59 and 64 are pivoted at 60 and 66 respectively, thereby moving the entire forming station 50 to any desired new position. This adjustment mechanism includes a rack 220 for each plate 61, and a pinion 222 engaged with each rack. These pinions are mounted on a shaft 224 carrying another pinion 226 engaged with a worm 228 which is rotatable by a knob 230. Thus when the knob is rotated, both plates 61 are moved correspondingly to adjust the longitudinal distance between the forming station 50 and the finishing station 124.

A change of the package repeat dimension also requires a change in the amount of indexing movement produced each cycle, i.e. a change in the effective gear ratio of the machine drive train. In the present embodiment,

this change is accomplished by altering the number of teeth on the Geneva sprocket, in incremental steps of two teeth at a time. The arrangement is such that for each two teeth added to this sprocket, the longitudinal movement of the clips 36 during indexing is increased by /8". Since as explained hereinabove the slots 3'7 of the clips 36 are uniformly spaced at intervals, the incremental change in indexing movement of /8" (or multiples thereof) will maintain the alignment between these slots 37 and the cutting knife 168; that is, the knife will always enter the slots and not strike the clips.

Another important feature of the disclosed machine is its compact configuration. In one aspect thereof, the overall length is minimized by providing the forming station 50 at the lower horizontal reaches of the chain movement, so that the length of the upper horizontal reaches need not be so great as to accommodate both the forming and finishing stations. This lower placement of the forming station requires that the film 30 be conducted around the curved path of the sprockets, but as noted hereinabove the problems of film tearing or distortion while traversing that curved path have been solved by using a special dimensional relationship between the clips 36 and the chain center-line which maintains virtually constant the gap between adjacent clips. The construction of the machine also has been simplified by placing the roll of top film 122 behind the machine (where it cannot be seen in FIG. 1), on a level with the bottom of the machine, and feeding the film from this roll through two right-angle turns around a triangular guide 230 having a smooth outer surface. Thus the machine framework need not be designed to carry the roll in the usual position above the line of packages, and this provides important simplifications in construction. Overall construction also has been simplified by arranging the sealing die so that evacuation takes place in the same position as does the peripheral heat sealing. By this means, atmospheric pressure during evacuations provides a substantial amount of the force required to make the seal, and thus the machine framework need not be designed to apply this force.

Referring again to FIG. 2, to the left of the package finishing station 124 are mounted a second pair of discs 232 which are engaged by the tabs 48 of the film clips 36 to open these clips for removal of the completed packages. Adjacent these discs are respective curved guides 234 positioned to engage the marginal side edges of the released packages, and arranged to cam these edges upward and out from between the fingers 38 and 40 of each opened clip in succession. Thereafter, the completed package rides down the far side of the guides 234 and lands on the chute 130, on which it exits from the machine.

Although a specific preferred embodiment of the present invention has been described hereinabove in detail, it is to be understood that this is merely to illustrate the invention and is not to be construed in a limiting sense, for it is clear that numerous modifications within the scope of the invention will be apparent to those skilled in this art.

What is claimed is:

1. Packaging apparatus comprising a plurality of elements arranged for intermittent indexing movement around a closed path, said elements including means to grip and support the opposite side edges of a series of cups so that the cups are suspended in position to be operated on to make packages, said cups having marginal portions around the open mouths thereof with an evacuation opening in the marginal portion for each cup, each of said cups being provided over the mouth thereof with packaging material adapted to form a top for closing the cup; a package finishing station adjacent one index position on said path and including a die defining a cavity shaped to receive said cups, a clamp operable with said die, said die and said clamp having seal means to engage said marginal portions of each cup, said seal means being arranged along a line extending around the entire periphery of the mouth of the cup at said one position and operable to efiect a permanent seal of said cup to its corresponding top at all points along said line to form an enclosed package; said seal means being located outboard of the evacuation opening of the cup at said one position so that the evacuation opening is located interiorly of said permanent seal line around the cup month; said finishing means further including vacuum means adjacent the evacuation opening of the cup at said one position and operable to withdraw air from the sealed package before it is moved to another position; and close-off means adjacent said vacuum means, said close-elf means being operable after the evacuation of said package to permanently seal together the cup and its top around said evacuation opening before the package has been moved to the next position, thereby to provide both evacuation and complete hermetic sealing of the evacuated package at a single position.

2. Apparatus as claimed in claim 1, wherein said elements comprise a plurality of clips arranged to grip a web of packaging film at the sides thereof; a forming station adjacent said path to form said web of material into said series of cups to be carried by said clips around to said finishing station; mean adjacent said path to make said evacuation opening in the marginal portions around each cup; means to apply said packaging material over the mouths of said cups to form said tops; and means to permit adjustment of said forming station longitudinally to accommodate changes in the package length.

3. Apparatus as claimed in claim 2, including a support base for said die, said base being mounted for reciprocating motion towards and away from the cups held by said clips; said vacuum means forming part of said base and including means extending up into the interior of said cavity; fastening means securing said die to said base, said fastening means being readily disengageable to permit the die to be removed and replaced with one of another size.

4. Packaging apparatus comprising a plurality of elements adapted to grip the side edges of a first continuous web of packaging material, said elements being arranged for intermittent indexing movement around a closed path; a forming station adjacent said path for forming said first web into a series of cups each having a margin around the open mouth thereof; means for making an evacuation slit through the trailing margin in each cup; means to apply a second web of packaging material over the mouths of said cups; package finishing means adjacent said path at one cup position subsequent to said web applying means; said package finishing means comprising seal means arranged to engage said two Webs along a line extending completely around the mouth of the particular cup at said one cup position to form a package; said seal line passing over the leading margin of the next following cup, said seal means at said leading margin forming a permanent seal between said two webs, said seal means at the remaining sections of said seal line providing a permanent seal between said two webs at least in all parts of said line not already permanently sealed; vacuum means adjacent the evacuation slit of the cup being sealed at said one position; said vacuum means being operable to evacuate the package through said evacuation slit before the package is moved to the next position; close-off means adjacent said vacuum means and operable after evacuation of said package to seal said two webs together around said slit before the package is moved to the next position, so as to complete the hermetic sealing of the package; and means forming part of said finishing means for sealing together the trailing margin of the next preceding cup while said means is operatively engaged With said particular cup to be sealed, thereby to make a seal line sealing otf the evacuation slit of that next preceding cup. 1

5. Apparatus as claimed in claim 4, wherein said seal means comprises a reciprocable die formed of wall means each having planar end surfaces serving as sealing elements, said wall means further being arranged to define a cavity to receive the cups after they arrive at said one position; said wall means including first and second walls extending along the outer side margins of each cup at said one position; a third wall extending transversely along the leading margin of the cup at said one position, and a fourth wall extending transversely along the leading margin of the following cup at the next position behind said one position.

6. Apparatus as claimed in claim 5, wherein said die includes a fifth sealing element located a small distance ahead of said third wall and arranged to effect a seal on the trailing margin of the preceding already-formed package in the position ahead of said one position.

7. Apparatus as claimed in claim 6, including knife means between said third and fifth sealing elements arranged to cut the package material transversely to separate the sealed packages into indiivdual units.

8. Packaging apparatus comprising a plurality of elements arranged for intermittent indexing motion around a closed path to carry a series of cups having margins around the mouths thereof and with an evacuation opening in the margin for each cup, means to apply packaging material over each cup to form a top therefor; a package finishing station adjacent one cup position on said path, said finishing station comprising first and second heat seal means both engageable with the margins of a cup at said one position; said first heat seal means extending at least substantially around the mouth of a cup at said one position and arranged to make a permanent seal between said cup and said packaging material completely around the mouth of the cup at said one position; said second heat seal means being located interiorly of said first heat seal means, said second heat seal means being movable towards and away from the margin of a cup at said one position and arranged to heat seal said packaging material to said margin completely around said evacuation opening.

9. Apparatus as claimed in claim 8, wherein said first seal means comprises a reciprocable die and a cooperating heated clamp, said die having wall means defining a cavity arranged to receive said cup at said one position, said wall means having planar end surfaces serving as seal elements to engage the margins around said cups, said second seal means including a member mounted for reciprocating motion within the cavity defined by said wall means and operable to press the packaging material adjacent the evacuation opening against the heated clamp to complete the seal around that opening.

10. Packaging apparatus comprising a plurality of elements arranged for intermittent indexing movement around a closed path to carry a series of cups having marginal portions around their mouths for sealing the cups to respective tops; means for applying packaging material over said cup mouths to form said tops; a package finishing station comprising a clamp member arranged to engage marginal portions of a cup stopped at that station; a die member including wall means defining a cavity shaped to receive the cup at that station, said die and clamp members having mated sealing elements for establishing a hermetically sealed chamber holding said cup and its top with said sealing elements gripping said marginal portions; means for effecting relative movement between said die and clamp members to permit operations to be carried out on successive cups; heating means in said clamp member to heat the sealing elements thereof to effect a permanent heat seal at said marginal portions; vacuum means to evacuate said chamber and to withdraw air from the package contained therein through an evacuation opening in a part of the marginal portions of the respective cup; and close-01f means reciprocable within said die member for pressing said marginal portion part of each cup against said heated clamp member to seal off the evacuation opening.

11. Apparatus as claimed in claim 10, wherein said elements comprise clip means arranged to grip the sides of a web of plastic film formed into said series of cups, thereby to hold the cups suspended in position to have packaging operations performed thereon.

12. Packaging apparatus comprising clip means arranged for indexing movement around two parallel closed paths, said clip means being adapted to grip the side edges of a series of cups and to support said cups suspended from said side edges to permit packaging operations to be performed thereon; means to apply packaging material to said cups to form tops thereof; a sealing die adjacent the line of movement of said cups and including wall means arranged to receive said cups; means mounting said sealing die for movement towards and away from said line of movement to engage said cups in succession; a sealing clamp on the side of said cups opposite to said sealing die and including sealing surfaces mating with corresponding surfaces of said sealing die to grip marginal portions around the mouth of a cup in the sealing die and to form an air-tight compartment around that cup; said clamp having a section inboard of said sealing surfaces which is recessed relative to said sealing surfaces to be normally out of contact with said packaging material; means for heating said clamp sealing surface and said recessed section; vacuum means to evacuate the air from the cup through an evacuation opening in one part of a marginal portion thereof inboard of said sealing surfaces; and a reciprocable pressure bar located within said sealing die and arranged to move against said marginal portion part to press it tightly together with the adjoining packaging material against said heated recessed section to heat-seal together the material around the evacuation opening.

13. Apparatus as claimed in claim 12, wherein said pressure bar is located between the sides of said sealing die.

14. Packaging apparatus comprising a large number of clips arranged to grip the side edges of a first web of packaging material and to provide intermittent motion of that web around a closed path having lower and upper reaches; means to feed said first web of packaging material to said clips at a position thereof on said lower reaches; a vacuum forming station on said lower reaches to form said web into a series of cups before said web arrives at said upper reaches, said vacuum forming station comprising a die mounted above said lower reaches and operable to form said cups with the mouths thereof facing downwardly; means at said upper reaches for applying a second web of packaging material over the upwardly facing mouths of said cups; a package finishing station at said upper reaches including means to seal the two webs of material together, said finishing station fur ther including means to evacuate the package formed by said sealed webs; said clips being carried by chains and positioned with respect to the corresponding chain centerline so that there is essentially no change in the gap between adjacent clips as they move around the curved portions of the path of movement, thereby to eliminate tearing or distortion of said firstweb as it is moved from said lower to said upper reaches.

15. Packaging apparatus comprising a large number of clips arranged to grip the side edges of a first web of packaging material and to provide intermittent motion of that web around a closed path having lower and upper reaches; means to feed said first web of packaging material to said clips at a position thereof on said lower reaches; a vacuum forming station on said lower reaches to form said web into a series of cups before said web arrives at said upper reaches, said vacuum forming station comprising a die mounted above said lower reaches and operable to form said cups with the mouths thereof facing downwardly; means at said upper reaches for applying a second web of packaging material over the up- Wardly facing mouths of said cups; a package finishing station at said upper reaches including means to seal the two webs of material together, said finishing station further including means to evacuate the package formed by said sealed webs; and means supporting said vacuum forming die in different positions providing difierent longitudinal distances between said die and the package finishing station, thereby to accommodate a change in the longitudinal dimension of the package.

16. Packaging apparatus comprising a pair of side-byside chains mounted for movement around a closed path having upper and lower reaches; a plurality of spaced clips mounted on said chain and facing inwardly to grip the side edges of a web of packaging material to carry that web around at least part of said closed path including a curved section thereof extending between said upper and lower reaches; a series of stations adjacent said path at both said upper and lower reaches, said stations including means for operating on said web of material to form packages therefrom; said clips being positioned with respect to the corresponding chain centerline so that there is essentially no change in the gap between adjacent clips as they move around said curved section of said path, thereby to eliminate tearing or distortion of said web as it moves around said path.

17. Packaging apparatus comprising a pair of side-byside chains mounted for movement around a closed path having upper and lower reaches; a plurality of spaced clips mounted on said chains and facing inwardly to grip the side edges of a web of packaging material to carry that web around at least part of said closed path; a series of stations adjacent said path including means for operating on said web of material to form packages therefrom; each of said clips comprising first and second cooperating fingers for gripping the web there'between; said first finger being fixedly secured to the corresponding chain; both of said fingers being formed with circular sections intermediate the ends thereof, said circular sections being in engagement to define a pivot axis extending parallel to the chain axis and accommodating rotary movement of said second finger with respect to said first finger; and spring means applying a force to said second finger urging it to rotate about said pivot axis in a direction to effect engagement between the outboard tips of said fingers, thereby to grip the web between said tips.

18. Apparatus as claimed in claim 17, wherein said second finger is formed with a tab portion located between its pivot axis and the corresponding chain; and cam means arranged to engage said tab portion to rotate said second finger about its pivot axis to spread said tips apart and permit insertion of the web of packaging material.

19. Apparatus as claimed in claim 17, wherein said spring means includes means to secure said second finger to said first finger.

20. Packaging apparatus comprising a plurality of elements arranged to hold a first continuous web of packaging material for intermittent indexing movement around a closed path, said web being formed into a series of cups each having margins around the open mouth thereof; means for making an evacuation slit through one margin of each cup; means to apply a second web of packaging material over the mouths of said cups; package finishing means adjacent said path at one cup position subsequent to said web applying means, said package finishing means comprising first seal means arranged to engage said two webs along a line extending completely around the mouth of the particular cup at said one cup position and including a section passing along the adjacent margin of another cup next in sequence, said seal means at said adjacent margin forming a permanent seal between said two webs, said seal means at the remaining sections of said seal line providing a permanent seal between said two webs at least in all parts of said line not already permanently sealed; vacuum means adjacent the evacuation slit of the cup being sealed at said one position and operable to evacuate the package through said evacuation slit before the package is moved to the next position; close-off means operable after evacuation of said package to seal said two webs together around said slit before the package is moved to the next position, so as to complete the hermetic sealing of the package; and second seal means operable subsequent to said first seal means for making a perment seal at said one margin of each cup interiorly of said evacuation slit to seal said slit from communication with the interior of the cup.

21. Apparatus as claimed in claim 20; wherein said second seal means is integrally mounted to said first seal means and is operative to make said permanent seal on a cup in the position next following said one position.

22. The method of making sealed packages from a continuous web of packaging material comprising the steps of advancing the web; forming the web into a sequential series of cups having a predetermined repeat spacing along the longitudinal axis of the web and with marginal portions around the mouth of each cup; applying a second web of packaging material over the mouths of said cups to provide tops therefor; sealing said second web to marginal portions at each cup in sequence, the seal line extending completely around the mouth of one cup and having a section thereof passing along a marginal portion of an adjacent cup so as to leave one marginal portion of said one cup unsealed; evacuating the. package thus formed through an opening between said seal line section and said unsealed one marginal portion; closing off said evacuation opening by sealing the two webs together in the region of said opening; advancing the evacuated package to a subsequent station; and sealing said two webs together along said one marginal portion of said cup to make a complete closed seal line passing over all of the marginal portions of said one cup.

23. Packaging apparatus comprising means arranged for motion around a closed path to carry a series of cups having marginal portions around the mouths thereof; means to apply packaging material over said cup mouths to make complete packages; a package finishing station adjacent said path and including a sealing die defining a cavity to receive and surround each cup in succession; a sealing head cooperable with said sealing die to heat seal said packaging material to the cup and effect a permanent outer seal line extending completely around the mouth of the cup; evacuation means at said finish ing station to evacuate the package while still in said sealing die to effect said heat seal, the evacuation taking place through an evacuation opening located interiorly of said permanent seal line; and close-01f sealing means at said finishing station and operable while the cup is still in said sealing die to effect a permanent seal between the cup and said packaging material around the. evacuation opening after the evacuation has been completed; the combination of the means for etfecting the outer seal line, evacuation, and close-off seal at the single finishing station making it readily possible to accommodate a change package size by replacing the sealing die with a different die suited to the changed package size.

24. Packaging apparatus comprising a plurality of elements arranged for intermittent indexing movement about a closed path to carry a continuous web of packaging material formed into a series of cups having marginal portions around the mouths thereof; means to apply a second web of packaging material over each cup to form a top therefor; a package finishing station adjacent one cup position on said path, said finishing station comprising means for heat sealing said two webs together to form a permanent seal line extending completely around the mouth of a cup at said one position; said heat seal means comprising a sealing die defining a cavity shaped to receive the cups and having sealing elements to engage the web of packaging material around each cup; evacuation means to withdraw air from the interior of each cup through a slit in one marginal position thereof; and a stud fixedly mounted within said cavity adjacent one wall of said die and directly beneath the part of said one marginal portion which is outboard of said slit, the top of said stud being aligned with the under surface of said one marginal portion so as to tend to hold the packaging material on one side of said slit in position during evacuation of the cup.

25. Apparatus as claimed in claim 24, including a heated part above said second web of packaging material in the region of said evacuation slit, and pressure bar means mounted for reciprocating motion along side of said fixed stud to engage the under surface of said one margi nal portion and press it up against said heated part to close off said evacuation slit after evacuation has been completed.

26. Apparatus as claimed in claim 25, wherein said stud is formed with an internal bore to permit the introduction of gas into the finished package after evacuation thereof.

27. Apparatus as claimed in claim 24, wherein said finishing station includes a base member mounted for reciprocating movement towards and away from the two webs of packaging material, means mounting said sealing die to said base for ready removal therefrom to permit replacement by a sealing die of different dimensions; said stud being fixedly secured to said base member for operation with any sealing die secured thereto.

28. Packaging apparatus comprising a plurality of elements arranged for intermittent indexing around a closed path to carry a series of cups having margins around the mouths thereof, means to apply packaging material over each cup to form a top therefor; a package finishing station adjacent one cup position on said path, said finishing station comprising heat seal means for making a permanent seal between said cups and said packaging material along a line extending completely around the mouth of a cup at said one position; said heat seal means having a portion thereof disposed to engage the margin of a cup at the next position beyond said one position so as to overlie part of the heat seal line previously produced by said heat seal means when the cup was in said one position.

29. Apparatus as claimed in claim 28, including second heat seal means located interiorly of the first heat seal means and movable relative thereto to heat seal an interior marginal portion of a cup in said one position to provide for closing off an evacuation opening therein.

30. Apparatus as claimed in claim 29, including third heat seal means integral with said first heat seal means and located exteriorly thereof, said third heat seal means being arranged to engage the cup at said next position so as to form a heat seal line overlying the close-ofi seal produced by said second heat seal means.

31. Apparatus as claimed in claim 30, wherein said third heat seal means is positioned to form a seal line running alongside said part of the previously produced heat seal line, whereby an evacuation opening therebetween can be isolated from the interior of a cup at said next position.

32. Packaging apparatus comprising means arranged for motion around a closed path to carry a series of cups having marginal portions around the mouths thereof; means to form evacuation openings in said marginal portions; means to apply packaging material over the cup mouths and said marginal portions to make complete packages; a package finishing station adjacent said path and including a sealing die defining at least one cavity reciprocably operable to surround each cup; a sealing head co-operable with the sealing die to establish a closed evacuation chamber within which an enclosed package is to be evacuated and hermetically sealed, said head and said die including interengageable means providing a gastight seal along an outer seal line extending completely around the mouth of a cup within the die and at least approximately coplanar therewith; evacuation means at said finishing station to evacuate the package while still in the sealing die, said evacuation means being positioned interiorly of said outer seal line and including means to evacuate the package through the evacuation opening in said marginal cup portion of a cup in said sealing die; and heating means at the finishing station operable, While the cup remains enclosed in the chamber formed by the sealing head and the sealing die, to effect a permanent heat seal between the cup and packaging material entirely around the cup mouth, said heating means including means operable to form a permanent heat-seal interiorly of the evacuation opening after the evacuation has been completed so as to prevent leakage of atmosphere into the package interior.

33. Packaging appears as claimed in claim 33, wherein said evacuation means comprises means interiorly of said outer seal line to establish a vacuum channel passing through said sealing die and communicating with an evacuation opening in said marginal portion outboard of the cup mouth.

34. Packaging apparatus as claimed in claim 33, including means operable to cut said evacuation opening in said marginal portion.

35. Packaging apparatus as claimed in claim 33, wherein said outer seal line is at least approximately rectangular in plan view, said evacuation opening being located adjacent one of the sides of the rectangle, said sealing means including means operable to form a permanent heat seal along a line parallel to said one side of the rectangle and at least partially interiorly of the evacuation opening.

36. Packaging apparatus as claimed in claim 33, wherein said sealing die includes flange portions surrounding said cavity and arranged to receive said marginal portions, said sealing head and sealing die being mounted for relative reciprocating motion, said sealing head including means engageable with said flange portions to establish said outer seal line.

37. Packaging apparatus as claimed in claim 36, wherein said sealing head has mounted therein heated means interiorly of the means for making said outer seal line and operable to form said permanent heat seal interiorly of the evacuation opening.

38. Packaging apparatus comprising means arranged for motion around a closed path to carry a first continuous sheet of plastic packaging material through a series of stations where packaging operations are performed along that path; first means adjacent said path to form said first sheet into cups having marginal flange portions around the mouths thereof; second means adjacent said path to cut the packaging material of a flange portion adjacent each cup so as to make an evacuation opening through the flange; third means adjacent said path to apply a second continuous sheet of packaging material over the cup mouths to make complete packages; a package finishing station adjacent said path and including a sealing die defining at least one cavity to receive and surround each cup in succession; a sealing head co-operable with said sealing die to establish a closed evacuation chamber, the engagement of said head and said die providing a gas-tight seal along an outer seal line extending completely around the mouth of the cup and coplanar therewith; evacuation means at said finishing station to evacuate the package while it remains in the sealing die cavity, said evacuation means being positioned inboard of said outer seal line and adjacent the cut flange porttion of the cup so as to communicate with the evacuation opening and evacuate the package through the flange interiorly of the outer seal; and heating means at the finishing station operable, while said cup remains in said die cavity and said evacuation means is in communication with said evacuation opening, to effect a permanent heat-seal between the cup flanges and the overlying second sheet of packaging material entirely around the cup mouth, said heating means including means arrranged to effect such permanent heat-seal in the region between the evacuation opening and the package cup while the package remains in said die cavity, so as to prevent leakage into the package interior after the package has been removed from said sealing die cavity.

39. Packaging apparatus as claimed in claim 38, wherein said sealing die is reciprocably-operable into a closed position providing said sealing chamber within which packages are both evacuated and heat-sealed at one stop; and vacuum means for evacuating said sealed chamber, above and below the package, so as to provide reduced pressure both inside and outside each package during the heatsealing thereof. 40. Packaging apparatus as claimed in claim 38, wherein said sealing head and sealing die include aligned surfaces which establish said outer seal along a line extending entirely around the mouth of one package and additionally encompassing at least a portion of the packaging material defining an immediately adjacent package, said evacuation means being positioned to evacuate said one package through an evacuation opening in the flange portion between the two packages prior to heat-sealing the pack age to cut off communication between that evacuation opening and the evacuated cup.

41. Packaging apparatus comprising means movable around a closed path to carry a continuous sheet of plastic packaging material for packaging operations at spaced positions along that path, said carrying means including two sets of clips mounted for movement on parallel paths and havmg opposed elements urged together to grip and support the side edges of the sheet of plastic packaging material, the interior regions of said sheet being formed into cups having marginal flange portions around the open mouths thereof; means to apply a second sheet of packaging material over the first sheet of packaging material to cover the cup mouths and make complete packages; said sheet-gripping clips being arranged to carry said first sheet with the second sheet positioned thereover into a package finishing station where the packages are evacuated and completely sealed hermetically at a single stop; said finishing station including a sealing die defining at least one cavity to receive and surround each formed cup; a sealing head co-operable with said sealing die to form a closed evacuation chamber, said head and said die providmg a gas-tight seal along an outer seal line extending completely around the cup, said outer seal line including sections running alongside the inboard ends of said clips immediately adjacent thereto; evacuation means at said finishing station to evacuate the package while it is in the cavity of said sealing die, said evacuation means including means defining a passage extending up through a part of said sealing die interiorly of the said outer seal line and positioned to evacuate the package through an evacuation opening in a marginal flange portion adjacent the package cup being evacuated; and heating means at the finish- 1ng station operable, while the cup remains in the cavity of said sealing die for evacuation of the package, to elfect a permanent heat-seal between the first and second sheets of packaging material extending entirely around the cup, said heating means including means operable after evacuation to effect such permanent heat-seal on an inner seal between said evacuation opening and the evacuated cup to prevent leakage of atmosphere into the package interior after the package has been removed from the sealing die cavity.

42. Packaging apparatus as claimed in claim 41, wherein said evacuation means includes means defining a vacuum passage located a substantial distance inboard of the sides of said sealing die which are next to said sheetgripping clips, said vacuum passage being positioned to communicate with an evacuation opening in a marginal flange portion between said outer seal line sections.

43. Packaging apparatus comprising a plurality of elements adapted to grip the side edges of a first continuous web of packaging material, said elements being arranged for movement around a closed path; means for moving said elements with an intermittent indexing motion providing a dwell period between indexing steps for carrying out packaging operations; a forming station adjacent said 17 path for forming said first web into cups having margins around the open mouths thereof; means for making an evacuation slit in the packaging material between pairs of adjacent cups; means to apply a second web of packaging material over the mouths of said cups and the margins thereof to form complete packages; a package finishing station adjacent said path at one position subse quent to said web applying means for evacuating and hermetically sealing each package at a single stop; said package'finishing station comprising a reciprocably-cooperable sealing die and sealing head having engageable seal means arranged to form an air-tight seal along an outer line extending completely around the mouth of one cup at said one position, said outer seal line encompassing the slitted margin adjacent said one cup and also encompassing at least a portion of the packaging material of the next adjacent cup beyond said evacuation slit; vacuum conduit means within said die aligned with the marginal evacuation slit of the package in said die at said one position; said vacuum conduit means being operable during a single dwell period to evacuate the package through said evacuation slit; and heating means operable at the package finishing station during the evacuation dwell period for producing a permanent heat seal between said two webs ofpackaging material entirely around the mouth of said one cup in said sealing die, said heating means including means operable to seal said two webs together between said evacuation slit and the mouth of said one cup before the package is moved to the next position, so as to evacuate and hermetically seal the package during a single dwell period of said intermittent indexing motion. 44. Packaging apparatus of the type wherein package sealing and evacuation take place at a single station, said apparatus being adapted for convenient changing of package dimensions and comprising:

a plurality of spring-loaded clips adapted to grip the side edges of a first continuous web of packaging material, said clips being arranged for movement around a closed path;

means for moving said clips with an intermittent in-' dexing motion providing a dwell period between indexing steps for carrying out packaging operations;

a forming station adjacent said path for forming said first web into cups having margins around the open mouths thereof;

means for making an evacuation slit in a margin in the packaging material between pairs of adjacent cups;

means to apply a second web of packaging material over the mouths of said cups and the margins thereof to form complete packages;

a package finishing station adjacent said path at one position subsequent to said web applying means for evacuating and hermetically sealing each package at a single stop;

said package finishing station comprising a reciprocable sealing die having a cavity to receive a cup;

a sealing head having means arranged to contact said die to form an air-tight seal between the two webs of packaging material along an outer seal line entirely encompassing the mouth of a cup in said die, said outer seal line comprising portions extending alongside but interiorly of said clips at the edge of the web of packaging material, said outer seal line also encompassing the slitted margin adjacent said one cup whereby access to the interior of the package in the die can be had through the slitted margin while the cup is sealed in the die;

heating means for maintaining the seal means at an elevated temperature so that the engagement between the seal means and the packaging material produces along said outer seal line between the two webs a permanent seal which is hermetically effective after removal of the package from the die;

vacuum conduit means at said die, said vacuum conduit means being aligned beneath the marginal evacuation slit of the package in said die at said one position and operable during a single dwell period to evacuate the package through said evacuation slit; and

close-01f sealing means operable at the package finishing station at the completion of evacuation for producing a permanent heat seal between said two webs of packaging material in a region between said evacuation slit and the mouth of said one cup before the package is removed from the die for transfer to the next position, thereby to evacuate and hermetically seal the package within a die which can readily be replaced with a similar die of different size to form different-sized packages.

45. Apparatus as claimed in claim 44, wherein said close-off sealing means comprises a heated element in said sealing head; and

reciprocable means operable to effect compressive engagement between the packaging material and said heated element while the package remains in the die after evacuation thereof.

46. Apparatus as claimed in claim 44, wherein said closed path of movement of said clips is generally oval in configuration, as seen in an elevation view, and includes both lower reaches and upper reaches;

means adjacent said lower reaches for applying said first web of packaging material to clips at said lower reaches;

said forming station being located at said lower reaches and operable to form cups in an upside-down position, the movement of the clips serving to carry the first web with the formed cups around the oval path to the upper reaches whereby the cups are inverted to right-side-up position to be loaded with product for packaging; and

said package finishing station being located at said upper reaches.

References Cited UNITED STATES PATENTS TRAVIS S. McGEHEE, Primary Examiner US. Cl. X.R.

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