US3763620A

US3763620A - Packaging apparatus and method

Info

Publication number: US3763620A
Application number: US00194279A
Authority: US
Inventors: G Giraudi; N Imperiale
Original assignee: WR Grace and Co
Current assignee: WR Grace and Co Conn
Priority date: 1970-11-04
Filing date: 1971-11-01
Publication date: 1973-10-09
Anticipated expiration: 1990-10-09
Also published as: ATA945571A; AT327804B; NL171788C; GB1353157A; IT954187B; AR192591A1; BR7107354D0; FI52053B; BE774853A; NL7115121A; BR7107349D0; DE2154268A1; NO134145B; DE2154268C2; NL171788B; LU64198A1; CH534611A; BR7107348D0; AU467894B2; FI52053C

Abstract

The invention relates to an automated vacuum bagging and sealing unit. In the device the size of an article is measured to determine the appropriate bag size and the article is then fed to a mechanically spreading bag holding guide. The filled bag is conveyed to a vacuum chamber including partial confinement bars and final gathering studs to effect clipping under high vacuum. Such a machine can be operated using only one operator and at throughput rates higher than previously possible.

Description

United States Patent [191 Giraudi et al.

[ PACKAGING APPARATUS AND METHOD [75] Inventors: Giorgio Aldo Maria Giraudi; Nino Imperiale, both of Milan Italy [30] Foreign Application Priority Data Nov. 4, 1970 Great Britain 52,465/70 .[52] [1.8. CI. 53/22 B, 53/59, 53/86, 53/1 12 B [51] Int. Cl B65b 31/02 [58] Field of Search 53/7, 12, 22B, 86, 53/89, 112 B [56] References Cited UNITED STATES PATENTS 2,924,924 2/1960 Garapolo et al. 53/112 B Oct. 9, 1973 2,850,856 9/1958 Mosse 53/89 Primary Examiner-Travis S. McGehee Attorney-John J. Tondy et a1.

[5 7] ABSTRACT The invention relates to an automated vacuum bagging and sealing unit. In the device the size of an article is"v measured to determine the appropriate bag size and the article is then fed to a mechanically spreading bag holding guide. The filled bag is conveyed to a vacuum chamber including partial confinement bars and final gathering studs to effect clipping under high vacuum.

Such a machine can be operated using only one operator and at throughput rates higher than previously possible.

8 Claims, 5 Drawing Figures PATENTED 9 975 SHEET 10F 4 PACKAGING APPARATUS AND METllllUlD This invention relates to apparatus for packaging articles and also to a method of packaging. A preferred form of the invention provides an apparatus and a method for vacuum-packaging hams.

In the packaging of articles such as hams it has been proposed to place the articles inside a bag of heatshrinkable thermoplastics material and to shrink the bag subsequently into a tight article-enveloping condition. In many cases the nature of the articles to be packed makes it advisable and often necessary to evacuate the interior of the bag before applying heat to shrink the bag material into a tight condition in which the space occupied by the finished package is kept at a minimum. Conventionally such vacuum packages are sealed by the applicationof a metal clip around the gathered neck of the plastics bag or by heat sealing the mouth of the bag. Any surplus plastics material can then be separated from the bag by cutting.

Among the many problems encountered with automating such packaging operations is the frequent oc currence of random-sized articles. For example, hams are conventionally pressed in moulds having an oval section and each mould is intended to pack hams of a given range of sizes or weights. Clearly the different sizes of hams will, upon compression in the mould, re sult in a different thickness of product although the mould will ensure that the length and width of the finished hams are constant for all hams within the size range intended for that mould. Thus cooked hams presented for packaging will be of varying sizes and will also have different ratios of height to length or width where the length and width are measured along the major and minor axes of an oval section of the ham.

According to a'first aspect of the present invention there is provided apparatus for packaging articles in bags and including a bag-filling station, means for feeding random sized articles towards said filling station and a classifying system responsive to at least two dimensions of the article for determining the size of bag on the basis of simultaneous assessment of the two dimensions. Preferably the articles may be fed along a single path towards the filling station and the classifying system may include an indicator to signal to an operator the size of the bag needed for enclosing the article. Alternatively a plurality of possible paths may be provided each leading to a respective one of a plurality of bag-filling units employing different sized bags, said classifying system being effective to direct the article along an appropriate path commensurate with the size of that particular article.

In one particularly suitable form of the invention the classifying system employs sensing devices for sensing the width and height of the article to be packaged, and the size of bag is selected on the basis of the sum of the width and height determined. In such an apparatus the summation operation may be carried out by an electrical movement-responsive device. The sensing devices may conveniently comprise mechanical sensing plates movable between retracted and article raising positions, and a triggering device adapted to move the sens ing members from their retracted positions into contact with an article in register therewith. The triggering device may suitably employ a photoelectric cell placed in register with a light source which creates a beam to be cut by the article on arrival adjacent the sensing devices.

A further problem experienced in connection with packaging of hams and other articles of similar form is that the hams have a fatty exterior which may readily be damaged.

It is therefore necessary for the bag-filling station to be carefully devised so that the bags may be placed over the ham without scraping too much fat from the sides of the ham.

According to a second aspect of the present invention there is provided apparatus for packaging articles in bags, and including a bag-filling station having a bag loading chute including a plurality of relatively movable guide members for holding a bag while an article is passed along said chute into the bag, a drive device for moving the guide members between a closely spaced bag-receiving position and a more widely spaced bag-spreading position in which they define a non-tapering article guide, and a classifying unit responsive to a dimension of an article to be packed and operative to control the spacing of the guide members in said article guiding position. Preferably the guide members may be mounted so that they always remain substantially parallel to their orientation in the nontapering article guide defining position.

Since, after moulding, cooked hams have a rectangular appearance when viewed from the front, i.e., when passing along a conveyor belt with the oval section parallel to the conveyor belt and with the longitudinal axis parallel to the direction of conveyor advance, it is convenient to cause the guide members to define the corners of a rectangular section passage so that the corners of an article such as a ham may be protected from damage by insertion into the bag.

Hitherto vacuum packaging of articles by clip-sealing within the plastics bags has been carried out by inserting the article within thebag, gathering the neck of the bag around a nozzle, evacuating the bag through the nozzle and finally clipping the gathered neck of the bag to effect a seal. One of the disadvantages of this arrangement is that atmospheric pressure acts on the bags during the evacuation phase so as to hold the bag firmly against the surface of part of the article with the result that the part of the bag remote from the finally gathered and clipped end tends to enclose air pockets.

According to a third aspect of the invention there is provided a vacuum packing chamber, means for feeding a filled but ungathered bag to said chamber, means within the chamber for gathering the neck of a hitherto ungathered bag, and means for fastening the gathered neck of a bag. It is thereby possible to carry out both the operations of gathering and fastening the neck of the bag within a vacuum chamber in order to eliminate all risk of air pockets. The evacuation is preferably carried out without the insertion of a nozzle within the bag and thus operation remains entirely automatic. Desirably the fastening means may comprise a clipping device, and preferably the gathering means includes means defining an elongate slot for confining the neck of the bag and a pair of gathering studs movable between positions at respective ends of said slot and a clipping position adjacent one another close to the centre of said slot so as to gather the bag neck prior to clipping. In a particularly suitable form of the invention the gathering studs include opposed clip-receiving slots which in the clipping position of said studs define a clip guide along which a clip may be passed during the clipping operation so that the clip will entrain the gathered neck during the clipping operation.

According to a fourth aspect of the present invention there is provided a method of vacuum packing including feeding a filled but ungathered bag into a chamber, evacuating the chamber, arranging the neck of the bag into a closely gathered configuration, and finally applying a clip to the closely gathered neck of the bag. Desirably the neck of the bag may be partially confined prior to evacuation of the chamber, provided the closely gathered configuration is not arrived at until after chamber evacuation, thus obviating the possibility of forming air pockets within the bag due to insufficient passage cross-section for escape of air through the partially gathered neck.

When applying a clip to a filled bag it is desirable for the clip to be applied at a location symmetrical with respect to the layout of the article. Thus, in the case of a ham, it is desirable for the clip to be applied at a location lying on the major axis of the median oval section through the ham.

According to a fifth aspect of the invention there is provided packaging apparatus including a clipping station, a conveyor for feeding a bag to the clipping station, a clipping device lying substantially in the plane of the conveyor, and a support table for holding the bag during the clipping operation and movable between a raised article-receiving position and a lowered bag clipping position. Desirably means may be provided for adjusting the level of the clipping position of the support table so as to allow for adjustment to accommodate a changed height of article. If such adjustment were not provided for, the level of the median plane would tend to displace. Conveniently the clipping station may be provided within a vacuum chamber and the clipping device may be integrated with a bag-gathering device. In such a case the bag-gathering device may be positioned substantially in the plane of a conveyor surface carrying the bag to the clipping station.

According to a sixth aspect of the present invention there is provided a method of applying a clip to a filled bag comprising feeding the bag along a conveyor to a clipping station, displacing the bag laterally so as to bring the median plane of an article within the bag into a position of register with the plane of the belt conveyor and clipping the neck of the bag while in said displaced position.

According to a seventh aspect of the present invention there is provided apparatus for packaging articles and including a bag loading station, means for feeding articles to the bag loading station, means for indicating to an operator at the bag loading station the size of bag required to envelop the next successive article arriving at the bag loading station, means for holding a bag selected by the operator, means for inserting the article with the held bag and means for advancing the bag from the bag loading station. Conveniently the apparatus may further include a downstream vacuum chamber and/or bag-gathering and fastening means. Conveniently a shrinking device may be provided downstream of such a vacuum chamber.

The invention also provides a package when formed by the method or apparatus of any of the above aspects of the invention.

In order that the present invention may more readily be understood, the following description is given,

merely by way of example, reference being made to the accompanying drawings in which:

FIG. 1 is a side elevational view showing the bag filling station of an automated ham packaging device illustrating the present invention;

FIG. 2 is a plan view of the device of FIG. 1;

FIG. 3 is a side elevational view of the vacuum chamber to be used to evacuate and seal the bags filled by the apparatus of FIGS. 1 and 2;

FIG. 4 is a top plan view of the chamber of FIG. 3; and

FIG. 5 is a side elevational view of one form of shrinking unit for use with the apparatus of FIGS. 1 to 4.

The bag filling device shown in FIGS. 1 and 2 comprises a conveyor table including a belt conveyor 1 for receiving hams which have just been removed from the cooking moulds and cleaned, for advancing hams along the table rightwardly towards a further belt conveyor 2 driven from the same power source but through suitable gearing so that the linear speed of the conveyor 2 is twice that of the conveyor 1, thereby increasing the separation between two successive hams on the conveyor 2. The hams are advanced along the conveyor 2 tea photoelectric source-sensor assembly 3 at which each ham will interrupt the beam and stop the two conveyors l and 2. A ham will thus be held stationary beneath a top sensing plate 5 and between a pair of side sensing plates 4 which will all then be driven towards the ham to contact the respective top and side surfaces and measure the height and width of the ham. The

sensing plates

4 and 5 start from a known reference position and the travel of each before contacting the ham is measured and used to derive a signal proportional to the hum of the height and the width of the ham. The sum mation operation is carried out by using an electric sensing unit, in which downward movement of the top plate 5 and relative closing movement between the side plates 4 are added together to derive a signal which, on departure of the ham from the

plates

4 and 5, is used to illuminate an appropriate one of four selector lamps 6 positioned on a battery 7 of support trays for carrying different sizes of bags.

Thus an operator merely needs to select a bag from the tray at the same level as the glowing lamp 6 and that bag will be sure to fit the next ham to arrive at the loading station. In practice the lamp 6 remains illuminated during movement of the ham from the sensing station over the battery of rollers 41 and onto a pair of parallel conveyor belts 8. having therebetween a longitudinally extending slot 8a.

The conveyor belts 8 advance the ham past another light source and sensor assembly 9 providing a beam cut off by the ham and then restored as the ham arrives at a position between two side sensing plates 10. The light source and sensor assembly 9 is connected so that, as the light beam is restored, the conveyor belts 8 are arrested. The side plates 10 are then driven inwardly to engage the sides of the ham to measure its width and this width signal is then fed to a suitable control system which effects lateral separating movement of corner plates 11 defining a loading guide for receiving a bag. The separating movement is indicated by the arrows 13 in FIG. 2. The ham will advance from the sensing plates 10 simultaneously with departure of the next successive ham from a position between the

plates

4 and 5; the lamp 6 being extinguished before the same or a different lamp is illuminated as a result of the signal derived by the

sensing plates

4 and 5 determining the size of the 7 opening the bag for the next ham just leaving

plates

4 and 5.

The guide plates 11 always start from a closely spaced condition in which the bag may easily be inserted thereover by the operator. Initially the plates 11 are spaced by laterally outward indexing movement along the arrows 13 so that the width of the loading guide or chute is equal to the width of the ham as sensed by the plates 10. Then the upper pair of plates ll which are pivotally mounted and spring loaded will be raised by movement along the direction of the arrow 14 until the bag is tensioned by the desired amount causing pivoting of the spring loaded plates and tripping of suitable microswitches (not shown). The degree of spring tensioning can, of course, be adjusted to suit the particular bag material employed.

This tripping of the limit switches, as a result of the resistance imposed on the upper arms 11 by the bag, initiates advance of the ham from the second sensing position between the plates and into the nontapering bag loading chute defined by the guide corner plates 11. This movement of the ham is effected by means of a pusher which rides in the above-mentioned slot 8a. The pusher, omitted from the drawings for the purposes of clarity, comprises a forwardly projecting arm which engages the rear of the ham and pushes it into, along, and then out of the guide 11, entraining the bag in so doing. The movement of the ham by the pusher continues along the direction of the arrow 15 until the ham reaches the position indicated in dotted lines at 16 on the chamber input conveyor 46 on the threshold of the evacuating chamber.

The pusher is disposed below the plane of the various conveyors l, 2 and 8 as the ham advances from the first or

size sensing station

4, 5 to the second or width sensing station 10, and is then raised once the ham has been sensed between the side plates 10. The battery of rollers 41, carried by a pair of levers, is caused to rise allowing the pusher to move forwardly and upwardly along the direction of the arrow 15 in FIG. 1 to appear from below the rollers 41. The advance and retraction strokes of the pusher are shown in FIG. I by arrows l5 and 17, respectively.

In order to economise on the time taken for the bag evacuating operation the device illustrated in FIGS. 3 and 4 employs a twin evacuating chamber which will simultaneously evacuate two bags side by side. In this way the throughput of hams can be increased to a value of the order of 10 per minute, this being the maximum practicable throughput rate of present day ham cooking and moulding plants.

The loading of the twin chamber is controlled by means of two parallel arrays of conveyor rollers 19, which, when required, can be driven for rotation in a ham-advancing sense. Interspersed between the rollers of the

arrays

19,20 are lateral shift bars 18 which move vertically and horizontally between the arrays so as to convey alternate hams from the position 16 on the rollers 20 to a parallel position 16a on the other of the arrays of rollers 19. The operation of the shift bars 18 is geared with respect to the operation of the ham loading guides 11 and conveyors 8 such that the shift guides execute one cycle of lateral'movement per two cycles of the loading chute. The shift bars 18 are raised to lift the ham 16 clear of the rollers 20, then moved horizontally to a position in register with rollers 19 and finally lowered to place the ham 16 on the rollers 19 after which the bars 18 move horizontally to a position below the rollers 20.

Once the machine has cycled to an extent commensurate with arrival of two successive hams on the arrays of

rollers

19 and 20 and retraction of the lateral shift bars 18 to a level below the array of rollers 20, the rollers I9 and 20 are driven for advancing movement to forward two hams in side by side relationship into the open vacuum chamber. The chamber includes a pair of feed conveyor belts 21 and main conveyor belts 22 disposed to define two parallel ham paths one along each side of the chamber. The conveyor belts 21 are separated from the belts 22 by a gap within which is positioned a vertically movable sensing roller 24. To the left of the sensing roller 24 is a track extending laterally across the chamber and containing four clipping studs the operation of which will be described separately later. The conveyors 22 are stopped once the trailing edge of each ham has passed over the sensing roller 24 and has allowed the roller to rise, indicating arrival of the two hams at their clipping positions. The conveyor belts 22 are vertically movable to descend through a distance equivalent to one half the height of the average ham being packaged, so that when the clip is applied it is substantially at the median plane of the ham, (i.e., the plane midway between the top and the bottom of the ham).

After clipping has been completed, the conveyors 22 again rise and advance the ham forward to a dipshrinking bath 37 (FIG. 5). Naturally, the movement of the ham along the

conveyors

21 and 22 will be carefully synchronised with operation of the vacuum chamber so that the hood of the vacuum chamber descends only when the ham is positioned entirely on the conveyor 22. The hood will then engage the base of the chamber in a sealing manner following which the air may be evacuated from the chamber which now contains two bags in side by side relation and having their necks confined as will be described below. Upon attainment of the desired degree of vacuum within the chamber an air pressure switch is tripped to actuate both the final gathering and clipping and also a cutting operation in which the surplus bag material is to a considerable extent severed from the remainder of the bag. It will be understood that the severing operation is deliberately left incomplete to ensure that the surplus material remains loosely attached to the remainder of the bag for subsequent removal by an operator, thereby avoiding the need for separate means for removing the severed end from the chamber, and also avoiding the possibility of obstruction of the evacuating conduits by the loose severed bag end. The subsequent advance of the vacuumpacked ham into the shrink tank is automatically effected once the hood 26 of the vacuum chamber is raised.

The dip shrinking bath shown in side elevation in FIG. includes a double walled tank 36 having in its upper part a support comprising a plurality of driven rollers 38 linked by a continuous chain to a driven shaft which, in the FIG. 1 position, is in register with a drive shaft and may be clutched thereto by means of a pneumatically operated dog clutch (not shown). However, upon arrival of a vacuum-packed ham on the array of rollers 38, the rollers stop rotating, the clutch becomes disengaged and the array of rollers is lowered into the tank 37.

The tank 37 is also provided with an automatic level sensing and control unit for ensuring that the level of shrinking water remains constant. A heater and thermostatic control system are also provided.

In order to avoid loss of steam from the hot water shrink bath, with the ensuing need to restore the lost heat and with the disadvantage that the escaping steam absorbed into the atmosphere surrounding the bag filling station may damage any loose unwrapped hams awaiting processing, the support rollers 38 are positioned above a plate 39 which engages sealingly with an inwardly extending flange 39a of the bath. Thus when the support rollers 38 are in their raised positions the shrink bath is sealed. Before downward movement of the rollers 38 to immerse the package, a dome-like hood 40 descends and sealingly engages the upper wall of the bath 37. Only when the hood 40 is in its sealing position will the support rollers 38 descend to immerse the ham in the shrinking medium, in this case, hot water.

In order to guard against flotation of the ham during the immersion operation the hood 40 of the dip shrink tank is provided with a perforated basket 45 which, after sealing of the hood 40, becomes automatically locked to the support rollers 38 and descendswith them. In this way the barn is dragged under water for the desired time interval to effect shrinking. After the shrinking operation is completed the support rollers 38 rise until the plates 39 engage with the flange 39a to reseal the tank. At this stage the perforated basket 45 becomes released from the rollers 39 and re-attaches to the hood 40 which rises carrying with it the basket. At this time the dog clutch re-engages and the rollers 38 are driven to advance the product to a collection station. It will be appreciated that the basket 45 may be dispensed with in applications where there will be no likelihood of the package floating on the water rather than sinking under its own weight.

Any steam which may become trapped inside the hood 40 during the immersion operation, and which might otherwise tend to disperse after opening of the dip shrink tank, will be hotter than the surrounding air and will be retained within the hood. However, any tendency for the steam to cool, condense and precipitate into the air below the hood can be averted by incorporating, within the hood 40, suitable forced-cooling means such as a cooling jacket. In this instance the forced-cooling means is in the form of water sprays which condense the steam during a very short interval before opening of the dip shrink bath and the condensed steam together with the spray water falls between the support rollers 38 to mingle with the remainder of the water in the bath 37 during the next immersion cycle.

It will be seen that the machine illustrated in the accompanying drawings and described above provides a fully automated packaging device in which the only need for manual intervention is in the placing of the appropriate sized bag over the corner plates 11 defining the loading chute. Even the operation of selecting the correct size of bag is carried out mechanically and thus there is virtually no chance that the machine will malfunction due to operator inefiiciency.

In the event of an oversized bag being chosen by the operator the machine will function quite normally and no stoppage will result, although it is possible that even after shrinking the oversized bag will be a loose fit on the ham. However, if an undersized bag is selected the two upper guide plates 11 will prematurely register tensioning of the bag, thus ceasing their upward movement, and accordingly obstructing the arrival of the next ham passing into the loading guide. In any event, the bar 12 extending across the machine at the inlet to the loading guide rises together with the upper corner plates or guide members 11 and, if raising of the bar 12 is stopped before arrival at a position in which it would clear the top of the next successive advancing ham, that next ham will strike an upstream switch plate 12a to shut down the conveyors 8 and the pusher mechanism. Shutdown of the conveyors 8 will cause a second successive ham to interrupt the light beam at the sensing assembly 9 at the input end of the width determining plates 10 and will prevent the beam from being restored. Thus the

conveyors

1 and 2 will stop and the flow of hams will cease until the operator has had a chance to remove the incorrectly positioned bag and to attach a correct bag for the size of ham next arriving at the loading station.

Although not described above, the downstream side of the beam 12 has a further switch plate 121; which in operation of the bag filling unit must be pressed by the operator to signal that a bag is in position on the guide members 1 1. Until the switch plate 12b is depressed the pusher will not advance the ham into the loading chute.

The relative separation and approach of the various guide members or comer plates 11 is. controlled by a closed hydraulic system which acts as a combined brake and lock on the drive to the corner plates 11. Movement of the members 11 is effected by means of pneumatic jacks which, at the appropriate instant, will urge their respective piston rods in a direction commensurate with separating movement of the corner plates 11. Each piston rod carries a secondary piston and extends sealingly through a secondary cylinder within which the secondary piston is sealingly slidable, the opposite ends of the secondary cylinder being linked by a closed hydraulic circuit including a shut-off valve. The degree of horizontal separating movement 13 of the corner plates 11 is controlled in such a way that once the separation of the comer plates 11 is equivalent to the width of ham sensed by the plates 10 the hydraulic shut-off valve is closed and the hydraulic system immediately locks the piston rod against further movement. Likewise, upon vertical separating movement along the direction of the arrow 14 the vertical movement will be stopped by its associated hydraulic mechanism the instant that the associated limit switch senses the pivoting of the upper comer plates 11 resulting from tensioning of the bag.

The clipping and gathering operation carried out within the vacuum chamber will be more clearly understood from the following description of the clipping and gathering devices provided.

The chamber of FIGS. 3 and 4 includes a magazine 29 for holding two parallel rows of clips each row being associated with the clipping system for one of the two bags within the chamber. The operation of the device is such that the leading clip in each row is moved laterally along the direction of the arrow 31 into a position referenced 36in which it is in alignment with the respective clipping guide 35 carried by the cover 26. At this stage the clip is ready for attachment to a bag and attachment merely involves pushing the clip upwardly at the appropriate moment by means of the clipping blade 30 driven by a pneumatic piston and cylinder arrangement 34. However, the actuation of the pneumatic jack 34 can only commence once the neck of the bag has been finally gathered.

The final gathering is effected by movement of the respective pairs of gathering studs 33 laterally across the device towards one another into a position in which they serve as guides for a single U-shaped clip.

However, before the final gathering step, the bag neck is initially partially confined by descent of a transverse bar 32 with the cover 26 of the chamber into a position in which it is above and spaced from the sensing roller 24. In this position the bag neck will be confined between the sensing roller 24 and the bar 32 but will be able to occupy the whole lateral extent of the respective half of the vacuum chamber. Thus the action of closing the chamber simultaneously effects partial confining of thebag neck. Evacuation of the chamber then takes place until the pressure switch indicates that the desired degree of vacuum has been attained, at which time the gathering studs 33 of each pair move together to effect final gathering of the neck of the bag by causing the lateralledges of the confined bag to approach a position in which they are very closely spaced. Once the studs are in this position they serve as guides for the clip since each stud has a slot extending longitudinally along one edge, the studs of each pair being arranged so that their slots face one another. It only remains then for the clipping blade 30 to rise pushing the clip 36 up along the guide slots in the co-operating studs 33 so that the free ends of the limbs of the U engage the clipping die 35 and are bent over to form a sealing closure around the neck of the bag.

Once the clips have been securely attached to the neck of the bag a severing knife blade 28 carried within the cover 26 of the chamber descends to effect partial severenceof the surplus bag material from alongside the clip. This hasthe result that the severed material remains within thecharnber and located by attachment to the bag from which it may be torn subsequently by an operator, for example during stacking of the packaged hams at the collection station.

The arrangement of the clip magazine outside the vacuum chamber in the device illustrated is considered particularly advantageous in that the chamber volume to be evacuated includes only the vertical passage through which the clip 36 moves between its ready position shown in FIG. 1 and the spent" position in which it is clipped on the bag. This volume is sealed from the remainder of the clip magazine so that there is no need for the clip magazine to be continually evacuated and re-exposed to atmospheric pressure. This reduces significantly the evacuation volume of the chamber. 1

Although the present invention has been described specifically in relation to the packaging of hams, and

equally to the packaging of a wide range of other types of articles. Thus the invention is by no means to be considered as limited to packaging of hams. Likewise, although in the preferred embodiment described and illustrated the components of the apparatus are joined together and interact to provide a fully automatic device for filling bags, evacuating the bags, clipping the bags, and shrinking the bags, it is contemplated that the present invention should include within its scope the employment of one or more of the components of the inventive apparatus with other conventional components. For example, the bag filling unit of FIGS. 1 and 2 may be employed with any other different type of bag evacuating and clipping device, and/or other forms of shrinking unit. Likewise the vacuum chamber of FIGS. 3 and 4 may be employed with an alternative arrangement of feed system and shrink tank.

We claim:

1. Packaging apparatus including a clipping station, a vacuum chamber within which the clipping station is disposed, a conveyor for feeding the bag to the clipping station, a clipping device lying substantially in the plane of the conveyor and a support table for holding the bag during the clipping operation and movable between a raised article receiving position and a lowered bag clipping position.

2. Apparatus for packaging articles in bags and including a bag loadingstation, means for feeding articles to the bag loading station, means for indicating to an operator at the bag loading station the size of bag required to envelop the next successive article arriving at the bag loading station, means for holding a bag selected by the operator, means for inserting said successive article within the held bag and for advancing the filled bag from the bag loading station, and including a vacuum chamber disposed to receive filled bags forwarded by the bag advancing means for evacuatingand sealing the filled bags.

3. A method of vacuum'pack'aging including the steps of feeding filled but ungathered bags into a chamber along a first path onto the threshold of the chamber and then alternate filled bags are shifted laterally toa second position also on the threshold of the chamber, closing and evacuating the chamber, arranging the neck of the bag into a closely gathered configuration, and fi nally applying a clip to the closely gathered neck of the bag.

4. Apparatus for vacuum packaging articles in bags, comprising a vacuum chamber, means for feeding a filled but ungathered bag to said chamber, means within the chamber for gathering the neck of a hitherto ungathered bag, and means within the chamber for fastening the gathered neck of a bag.

5. Apparatus as set forth in claim 4, wherein the fastening means comprises a clipping device; and wherein the gathering means includes meansdefining an elongate slot for partially confining the neck of the bag, and a pair of gathering studs movable between starting positions at respective ends of said slot and a clipping position adjacent one another close to the centre of said slot so as to gather the bag neck prior to clipping.

6. Apparatus as set forth in claim 5, wherein the gathering studs include opposed clip-receiving slots which in the clipping position of said studs define a clip guide along which a clip may be passed during the clipping operation to entrain and fasten the gathered bag neck.

7. Apparatus for vacuum packaging comprising a vacuum chamber; means for filling heat scalable bags; a conveyor for transporting the filled bags towards said vacuum chamber; a pair of parallel conveyors arranged side by side to feed two filled bags simultaneously into the chamber, one of said parallel conveyors being arranged to receive the filled bags from the first mentioned conveyor; transfer means driven to transfer alroller conveyors onto the other of the roller conveyors. k i a: i

Claims

2. Apparatus for packaging articles in bags and including a bag loading station, means for feeding articles to the bag loading station, means for indicating to an operator at the bag loading station the size of bag required to envelop the next successive article arriving at the bag loading station, means for holding a bag selected by the operator, means for inserting said successive article within the held bag and for advancing the filled bag from the bag loading station, and including a vacuum chamber disposed to receive filled bags forwarded by the bag advancing means for evacuating and sealing the filled bags.

3. A method of vacuum packaging including the steps of feeding filled but ungathered bags into a chamber along a first path onto the threshold of the chamber and then alternate filled bags are shifted laterally to a second position also on the threshold of the chamber, closing and evacuating the chamber, arranging the neck of the bag into a closely gathered configuration, and finally applying a clip to the closely gathered neck of the bag.

5. Apparatus as set forth in claim 4, wherein the fastening means comprises a clipping device; and wherein the gathering means includes means defining an elongate slot for partially confining the neck of the bag, and a pair of gathering studs movable between starting positions at respective ends of said slot and a clipping position adjacent one another close to the centre of said slot so as to gather the bag neck prior to clipping.

7. Apparatus for vacuum packaging comprising a vacuum chamber; means for filling heat sealable bags; a conveyor for traNsporting the filled bags towards said vacuum chamber; a pair of parallel conveyors arranged side by side to feed two filled bags simultaneously into the chamber, one of said parallel conveyors being arranged to receive the filled bags from the first mentioned conveyor; transfer means driven to transfer alternate filled bags arriving on said one of the parallel conveyors onto the other of said parallel conveyors; and means for actuating the two parallel conveyors simultaneously after delivery of a further filled bag on said one of the parallel conveyors.

8. Apparatus as set forth in claim 7, wherein said parallel conveyors are roller conveyors and said transfer means comprises pushers arranged to project upwardly through the inter-roller spacings of the parallel conveyors to urge an article laterally from said one of the roller conveyors onto the other of the roller conveyors.