NO134145B - - Google Patents

Abstract

Apparatus for vacuum packing.

Description

The present invention relates to an apparatus for vacuum

packaging where a filled bag with an unassembled bag neck is fed into a vacuum chamber which is then closed to empty the bag's interior and exterior before a clamp is applied to close the bag neck.

When packing items such as hams, it has been

method of placing the articles into a bag of heat-shrinkable thermoplastic material and then shrinking the bag into a tight article-wrapping condition. In many cases the nature of the items to be packed makes it advisable and often necessary to pump out the air in the bag because heat is added to shrink the bag material to a tight condition, in which the space occupied by the finished package is held a minimum.

Generally, such vacuum packs are sealed in use

by a metal clamp around the combined plastic bag neck or by heat sealing the bag opening. Any excess plastic material can then be separated from the bag by cutting.

A problem experienced in connection with the packaging of hams

and other objects of a similar shape occur where objects

they have a fatty exterior (like the exterior of a cooked ham),

which can easily be dislodged or loosened during emptying of the bag for vacuum packaging.

For the vacuum packing of objects in bags, there have been two methods to date, namely the nozzle emptying process and the chamber emptying process.

Nozzle emptying has previously been successfully carried out with objects

such as poultry. The neck of the filled bag is collected around a nozzle and the bag is emptied through the nozzle for final shearing to effect a seal. One of the disadvantages of this device is that atmospheric pressure acts on the parts of the bag that are far from the neck

during the emptying phase so as to hold these remote parts firmly against the surface of a part of the object with the result that the remote parts tend to surround air pockets. This problem is exacerbated when the item has a fatty outer covering such as for a cooked ham in that the bag tends to adhere more easily to the surface of the item. The other well-known packaging method, the vacuum chamber process, has so far not been successful with larger items such as cooked hams, as it has been necessary to collect the neck of the bag for the closure of the chamber. Certain vacuum chamber systems use e.g. a nozzle, on which the bag is collected manually to close the chamber. This allows the interior and the exterior of the bag together to be exposed to vacuum in a controlled manner so as to allow the air within the bag to escape relatively easily. However, this is not automatic, and entails the disadvantage that during the entire emptying phase the neck of the bag remains gathered around the object, thereby limiting the passages

through which air in the object will normally be drawn into the nozzle.

German Offenlegungsschrift No. 1 761 844 (Barroso) has proposed a vacuum chamber system where there is no need for an emptying nozzle, but instead the bag is first partially assembled in an arc-shaped slot along which the bag closing clip is then driven to complete the bag assembly. Nevertheless, this device shares the same disadvantages as the nozzle system in that the bag must be relatively tightly assembled before the vacuum chamber can be closed and vacuum introduced.

The present invention aims to provide a vacuum chamber packaging apparatus where the bag can be inserted in a completely unassembled form, and can be completely assembled and closed automatically by means of non-manual means while in the chamber.

The present invention is characterized by a pair of opposed slit-defining members which are mounted parallel to each other for movement towards and away from each other to define an elongate slit for partial constriction of the bag neck, a pair of collecting members which are movable towards and away from each other along paths which are parallel to the gap-defining bodies, and a conveyor which determines the feed path of an object and which passes between the gap-defining bodies when these are in their ist kt separated positions. This allows the filled bag to pass, bottom first, between the slit-defining means and the collecting means, and to be stopped with the rear mouth end of the bag in line with the slit-defining and collecting means, so that shearing can take place after collection in the closed chamber. The widest possible escape route is thus given to the air escaping from the bag.

Preferably, the invention is further characterized in that the gap-defining members are horizontal bars which extend across the direction of the article's feed path and are mounted for movement between a separate position, in which the lower gap-defining member is just below the article's feed path and the upper gap-defining member is widely separated from and above the web to allow an object to pass between the lower and upper members, and a gap-defining position, in which the upper member has been lowered to lie close to but just above the lower gap-defining member, and that the collecting means are pins or the like which extend vertically and are movable horizontally towards and away from each other between an open position and a closed position in which they are spaced apart to a small degree to completely constrict the neck of a filled bag on the feed conveyor. This means that the objects can pass along a flat belt or roller conveyor into the apparatus, and can first be collected by means of vertically moving, horizontally extending slot-defining means that shape the bag neck into a loose horizontal slot which is then closed by the two remaining, vertical collecting means that come together to completely constrict the bag neck for closure.

The invention is further characterized in that two side-by-side conveyors are provided to allow a pair of filled bags to be fed simultaneously into the vacuum chamber in a side-by-side relationship, that each of the gap-defining members is long enough to for-lope over the double width of the conveyors to act simultaneously on two filled bags in the chamber to partially collect the necks of these filled bags, that there are two parallel conveyors arranged side by side to feed two filled bags simultaneously to the conveyors in the chamber , that a push member is arranged to feed one of the conveyors, and that a transfer carrier is driven to alternately transfer items arriving on said one of the parallel conveyors, so that the two parallel side-by-side conveyors can be activated simultaneously after delivery of a further filled bag on said one conveyor. This allows the two bags to be emptied at the same time and reduces energy consumption by the fact that the air space in the chamber only needs to be emptied once for every two items to be packed. A collection mechanism is common to the two side-by-side conveyor feed paths in this embodiment.

Advantageously, the apparatus is further characterized in that the conveyor is in the form of a support table for holding the bag during the collecting and clamping operation and is movable between an upright object receiving position and a lowered bag closing position, and that the lower gap defining member is a roller which is located at the entrance end of the support table . This improves the gathering effect as the support table lowers relative to the roller forming the lower gap defining member and this helps to gather the lower part of the bag neck upwards towards the median horizontal plane of the article.

In addition, the apparatus can be further characterized by a per se known clamping device for applying a clamp around the combined bag neck between the collecting means and the gap-defining means, and opposite clamp-receiving slits in the collecting means which, in the closed position of said collecting means, define a clamping guide along which a clamp can pass during the clamping operation so that the clamp will be fed into the assembled bag neck during the clamping operation. In this way, where the bag is to be closed by means of a clamp, it is possible for the collecting means to serve both as collecting means and clamping liner, and this provides a particularly simple and compact device for the apparatus.

In order that the present invention may be more easily understood,

the following description is given, essentially by means of examples, and where reference is made to the accompanying drawings in which: Fig. 1 is a side view showing the bag filling station for an automated ham packaging device, which illustrates the present invention,

fig. 2 is a plan view of the body in fig. 1,

fig. 3 is a side view of the vacuum chamber to be used to empty and seal the bags filled by the apparatus of FIG. 1

and 2,

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

fig. 5 is a side view of one type of crimping unit for use with the apparatus of FIG. 1-4.

The bag filling member as shown in fig. 1 and 2 comprise a conveyor table which includes a belt conveyor 1 for receiving hams which have just been taken out of the cooking forms and cleaned, for advancing hams along the table straight ahead towards a further belt conveyor 2 which is driven from the same power -source, but through an appropriate exchange, so that the linear speed of the conveyor 2 is twice that of the conveyor 1, thereby increasing the distance between two subsequent hams

on conveyor 2. The hams are fed forward along conveyor 2

to a photoelectric source decoiler unit 3, by which each ham will break the beam, stopping the two conveyors 1 and 2. lin ham will thus be held stationary under a top decoiler plate

5, and between a pair of side deflector plates 4, which will then be driven towards the ham for contact with the top and side surfaces respectively and measure the height and width of the ham. The decoiler plates 4 and 5 start from a known reference position, and the movement of each in contact with the ham is measured and used to derive a signal proportional to the sum of the height and width of the ham. In summary, the operation is carried out by using an electrical de-sensing unit, in which downward movement of the top plate 5 and relative closing movement between the side plates 4 are added to derive a signal which, when the ham leaves the plates 4 and 5, is used to ignite a particular lamp of four selector lamps 6 placed on a battery 7 of support boards to hold different bag sizes.

. Thus, for the most part, an operator only needs to select a bag from the board on it: the same level as the lamp 6, and the

the bag will fit the next ham arriving at the loading station. In practice, the lamp 6 remains illuminated during the movement of the ham from the de-coiling station over the battery of the roller 41 and to a pair of parallel conveyor belts 8 with a longitudinally extending slot 8a.

The conveyor belts 8 advance the ham past another light source and detector unit 9 which causes a beam interruption due to the ham and then restored when the ham arrives at the position between two side detector plates 10. The light source and detector unit 9 are connected so that, when the light beam is restored, the conveyor belts 8 stopped. The side plates 10 are then driven inward to contact the ham sides to measure its width, and this width signal is then fed to an appropriate control system, which performs side separation movement of the corner plates 11, which determines a load controller for receiving a bag. The separating movement is indicated by means of arrows 13 in fig. 2. The ham will be fed forward from the decoiler plates 10 simultaneously with the departure of the next successive ham from a position between the plates 4 and 5, where the lamp 6 is extinguished for the same or another lamp is lit as a result of the signal received from the decoiler plates 4 and 5, which determine the size of the next ham.

It is clear that when the plates 10 determine the width of the ham to be fed into the bag loading chute determined by the corner plates 11, the plates 4 and 5 will simultaneously determine the height and width of the next consecutive ham to thereby influence the appropriate bag size selection lamp 6 to shine. Thus, while the corner plates 11 expand to open a bag for the ham leaving the plates 10, the operator can already choose to open the bag for the next ham just leaving the plates 4 and 5.

The guide plates 11 always start from a slightly separated state, in which the bag can easily be inserted over there by the operator. In the beginning, the plates 11 are separated by a sideways outward step-by-step movement along the arrows 13, so that the width of the load guide or shaft is equal to the width of the ham as unfolded by the plates 10.

The upper pair of plates 11, which is rotatably mounted and spring-loaded, will then be raised by movement along the direction of arrow 14 until the bag is stretched to the desired length causing rotation of the spring-loaded plates and triggering of appropriate micro-switches (not shown) . The degree of tension can of course be adjusted to suit the particular bag material used.

This tripping of the limit switches, as a result of the resistance exerted by the bag on the upper arms 11, initiates the advancement of the ham from the second defiler position between the plates 10 and the non-pointing bag loading chute determined by the guide corner plates 11. This movement of the ham is carried out by using a pusher that runs in the above-mentioned column 8a. The pusher, which is omitted in the drawings, for the sake of clarity, comprises a forwardly projecting arm which grasps the back of the ham and pushes it into, longitudinally, and then out of the guide 11, thereby placing it in the bag. The movement of the ham by means of the pusher continues along the direction of the arrow 15 until the ham reaches the position indicated by dashed lines at 16 on the chamber entrance conveyor 46 on the threshold of the discharge chamber.

The pusher is arranged below the plane of the different conveyors 1, 2 and 8, when the ham is fed forward from the first or size de-filling station 4, 5 to the second or width de-filling station 10, and is then raised as soon as the ham has been cut between the side plates 10. The battery of rollers 41, carried by a pair of weights, is caused to rise to allow the pusher to move forward and upward along the direction of arrow 15 in fig. 1

to appear under the rollers 41. The advancing and retracting layers of the pusher are shown in fig. 1 at the arrows 15 and respectively. 17.

To economize on the time that the bag deflation operation takes,

then uses the device, which is illustrated in fig. 3 and 4, a double pumping-out chamber that will pump out two bags side-by-side at the same time. In this way, the amount of hams that pass can be increased to a value of the order of ten per minute, where this is the maximum practical throughput speed in today's factories for cooking and shaping hams.

The loading of the double chamber is controlled by means of two parallel rows of conveyor rollers 19, 20, which, when desired,

can be operated for turning in a ham feeding direction. Hospitalized

between the row rollers 19, 20 there are side shift rods 18 which move

themselves vertically and horizontally between the rows in order to transfer . alternate hams from position 16 on the rollers 20 to a parallel position 16a on the second of the row rollers 19. The operation of the shift rods 18 is adapted to the operation of the ham loading guides 11 and the conveyors 8, so that the shift guides carry out a transverse movement cycle per . two cycles for the loading chute. The shifting rods 18 are raised to lift the ham 16 clear of the rollers 20,

is then moved horizontally to a position in agreement with the rollers 19 and finally lowered to place the ham 16 on the rollers

19, after which the bars 18 move horizontally to a posi-

tion under the rollers 20.

As soon as the machine has turned to a degree corresponding to the arrival

of two consecutive hams on the row of rollers 19, 20, and the retraction of the side shift rods 18 to a level below the row of rollers 20, the rollers 19 and 20 are driven for forward movement to send two hams in side-by-side relationship into in the open vacuum chamber. The chamber comprises a pair of feed conveyor belts 21 and main conveyor belts 22 which are arranged to define two parallel ham paths with one along each side of the chamber. The conveyor belts 21 are separated from the belts 22 by a gap within which a vertical movable deburring roller 24 is placed. To the left of the deburring roller 24 there is a groove which runs laterally across the chamber and contains four clamping pins, the operation of which will be described separately later. The conveyors 22 are stopped

pet as soon as the trailing edge of each ham has passed over the deburring roller 24, and has allowed the roller to rise, indicating the arrival of the two hams at their clamping positions. The conveyor belts 22 are vertically movable to be able to lower a dis-

equal to half the height of the average ham being packed, so that when the clamp is put on, it is essentially at the median plane of the ham (i.e. the plane halfway between

loin the top and bottom of the ham).

After clamping has been completed, the conveyors 22 are raised

again, and transports the ham forward to a dip shrinking bath 37 (fig^ 5). Naturally, the movement of the ham along the conveyors 21 d 22 will be carefully synchronized with the operation

of the vacuum chamber, so that the cap for the vacuum chamber only descends when the ham is placed completely on the conveyor 22. The cap will then be brought into contact with the chamber's base in a sealing manner, after which the air can be pumped out of the chamber, which now contains two bags in side- side-by-side conditions, and which have their necks narrowed as will be described below. After achieving the desired degree of vacuum within the chamber, an air pressure switch is triggered to effect both the final gathering and clamping, and also a cutting operation during which the excess bag material is substantially separated from the remainder of the bag. It will be understood that the separation operation is intentionally left incomplete to ensure that excess material remains loosely attached to the remainder of the bag for subsequent removal by an operator, thereby avoiding the necessity of separate means for removing the separated end from the chamber, and also avoid the possibility of clogging of the discharge pipes due to loose separated bag ends.

The subsequent feeding of the vacuum-packed ham into the shrinking tank is carried out automatically as soon as the hood 26 for the vacuum chamber is raised.

The dip shrink bath which is shown in side view in fig. 5 comprises a tank 37 with double walls, which has in its upper part a support comprising a plurality of driven rollers 38, which are connected by means of an uninterrupted chain to a driven shaft which, in the position in fig. 1 is in cooperation with a drive shaft and can be connected thereto by means of a pneumatically operated tooth claw coupling (not shown). Upon the arrival of a vacuum-packed ham on the row of rollers 38, the rollers stop rotating, the coupling is disconnected and the row of rollers is lowered into the tank 37.

The tank 37 is also equipped with an automatic level sensor and control unit to ensure that the level of the shrinking water remains constant. A heater and thermostatic control system are also provided.

In order to avoid the loss of steam from the hot water shrink bath, with the consequent necessity of rebuilding the lost heat, and with the disadvantage that the steam escaping and being absorbed into the atmosphere around the bag filling station may spoil any lot of unwrapped ham awaiting processing, the supporting rollers 38 are placed over a plate 39 which is brought into sealing engagement with the inwardly extending flange 39a in the bath. Thus, the shrink bath is sealed when the support rollers 38 are in their raised positions.. For downward movement of the rollers 38 to lower the package, a dome-like cap 40 descends and in a sealing manner is brought

in engagement with the upper wall of the bathroom 37. Just reaches the hood 40

is in its sealed position, the support wells 38 will descend to immerse the ham in the shrink medium, in this case hot water. •<->*>■•■'■<->"<-->" ;In order to protect against floating of the ham during the immersion operation, the hood 40 of the dip shrink tank is equipped with a perforated basket 45, which, after sealing of the cap 40,, becomes auto- ■' ■''. X'-l" mechanically locked to the support rollers 38 and sinks with them. In this way the ham is pulled under water for the desired time interval; to effect crimping. After the crimping operation is completed, the support rollers 38 rise until the plates 39 are brought into engagement with the flange 39a to reseal the tank. At this stage, the perforated basket 45 is detached from the rollers 30 and reattached to the cap 40, which then rises as it follows the basket. At this point, the tooth claw coupling is re-engaged, and the rollers 38 is operated to advance the product to a collection station. It is obvious that the basket 45 can be used in applications where there is no likelihood that the package will float on the water instead of sinking due to its own weight. Any steam which can be trapped inside the cap 40 during the immersion operation, and which may otherwise tend to spread after the opening of the dip shrink tank, will become hotter than the surrounding air, and will be held inside the cap. d, any tendency for the steam to condense, condense and precipitate in the air under the hood can be prevented by operating, within the hood 40, appropriate means for forced cooling, such as a cloak. In this case, the means for forced cooling are in the form of water vaporizers which condense, the steam in the course of "a very short moment for the dip shrink bath ..opens, and the condensed steam; together with the first water" water falls between the support rollers 38 to mix with the rest of the water, in the bath 37 during the next immersion cycle."' v ;It will be seen that the machine illustrated in the accompanying drawings and described above constitutes a fully automated packaging device in which the only need for manual intervention is by placing the bag of suitable size over the corner plates li which determine the loading chute. The operation of selecting the correct bag size is even done mechanically, and thus there is virtually no chance of the machine malfunctioning due to operator error. In the event that a bag that is too large is selected by the operator, the machine will function quite normally, and no stoppage will occur, although it is possible that even after shrinking, the bag that is too large will be stuck on the ham. However, if a bag of too small a size is selected, the two upper guide plates 11 will sense in advance the tension in the bag, thus stopping their upward movement, and correspondingly preventing the arrival of the next ham passing into the load guide. In any case, the bar 12, which extends across the machine at the entrance to the load guide, is raised together with the upper corner plates or guide members 11 and, if the raising of the bar 12 stops short of arriving at a position in which it would clear the top of the next successively emerging ham, this ham would hit an upstream breaker plate 12a to stop the conveyors 8 and the push mechanism. Stopping the conveyors 8 will cause another subsequent ham to interrupt the light beam at the decoiler unit 9 at the input end of the width determination plates 10 and will prevent the beam from re-emerging. Thus, the conveyors 1 and 2 will stop and the flow of hams will increase until the operator has had a chance to remove the incorrectly placed bag and attach a correct bag for the stem movement of the ham that then arrives at the loading station. Although not described above, the downstream side of the jet 12 has a further switch plate 12b which, when operating the bag filling unit, must be pressed by the operator to signal that a bag is in position on the control elements 11. The pusher will not feed the ham into the loading chute for the switch plate 12b is pressed down. ;The relative separation and approach of different: control elements or corner plates 11 is controlled by means of a closed hydraulic system which acts as a combined brake and lock on the drive of the corner plates 11. The movements of the elements 11 are carried out by means of pneumatic jacks which, in the appropriate moment" will force their respective piston rods in a direction corresponding to the separating movement of the corner plates 11. Each piston rod carries a secondary piston and extends in a sealed manner through a secondary cylinder within which the secondary piston is slidably sealed, where the opposite ends of the secondary cylinders are connected by means of a closed hydraulic circuit which includes a shut-off valve. The degree of horizontal separation movement 13 of the corner plates 11 is controlled in such a way that as soon as the separation of the corner plates 11 is equal to the width of the ham that is felt by the plates 10, the hydraulic shut-off valve is closed, and the hydraulic system instantly locks the piston rod against further movement. Likewise, in the case of vertical separation movement along the direction of the arrow 14, the vertical movement will be stopped by its associated hydraulic mechanism at the moment that the associated limit switch detects the rotation of the upper corner plates 11 which originates from the tension of the bag. The clamping and gathering operation carried out within the vacuum chamber will be better understood from the following description of the clamping and gathering means which are provided. ;The chamber in fig. 3 and 4 comprise a magazine 29 for holding two parallel rows of clamps where each row drills the clamping system for one of the two bags within the chamber. The operation of the means is such that the leading clamp in each row is moved laterally along the direction of the arrow 31 to a position indicated by 36, in which it is aligned with the respective Jclamp guide 35, which is carried by the cover 26. At this stage the clamp is ready for attachment to the bag and attachment essentially involves pushing the clamp upwards at the appropriate moment by means of the clamp blade 30, which is operated by means of a pneumatic piston and cylinder device '34.* However, the actuation of the pneumatic jack 34 may only start when the neck of the bag has been finally gathered.

The final assembly is performed by moving the respective pairs

of bus pins 33 laterally across the device against each other to a position in which they serve as guides for a simple U-shaped clamp.

For the final assembly step, however, the bag neck is first partially constrained by the lowering of a transverse rod 32 with the cover 26 for the chamber in a position in which it is above and separated from the deflating roller 24. In this position, the bag neck will be constrained between the deflating roller 24 and the rod 32 , but will be able to occupy the entire lateral extent of the respective half of the vacuum chamber. Thus, the closing action of the chamber simultaneously performs partial restriction of the bag neck. the deflation of the chamber then takes place until the pressure switch indicates that the desired degree of vacuum has been achieved, at which time the collection pins 33 of each pair come together to effect final collection of the bag neck by causing the side edges of the restricted bag to approach themselves a position in which they are very close to each other. As soon as the pins are in this position, they serve as guides for the clamp, each pin having a slot which runs longitudinally along an edge, where the pins for each pair are arranged so that their slots face each other. It then only remains for the clamp blade 30 to rise, whereby the clamp 36 is pushed up along the guide slots in the cooperating pins 33, so that the free ends of the branches of the U are brought into engagement with the clamp form 35 and are reshaped to form a sealing closure around the bag neck.

As soon as the clamps have been:securely attached to the bag neck,

if a cutting knife blade goes down NOK 28. which is carried within the chamber cover 26, to effect partial separation of excess bag material along the clamp. This results in separated material remaining within the chamber and located by attachment to the bag from which it can then be torn off by an operator, e.g. during stacking of the packed hams at a collection station.

The arrangement of the clamp magazine outside the vacuum chamber in the device shown is considered particularly advantageous in that the chamber volume to be pumped out comprises only the vertical passage through which the clamp 36 moves between its "ready" position shown in fig. 1, and the "used" position, in which it is clamped on the bag. This volume is sealed from the rest of the clamp magazine, so that there is no need for the clamp magazine to be continuously pumped out and re-exposed to atmospheric pressure. This significantly reduces the pump-out volume of the pump-out chamber"

Although the present invention has been described particularly with respect to the packing of hams, and although some of the preferred features of the invention were derived as a result of the necessity of packing hams in a fully automatic machine and without damage to the hams, it can be understood as a matter of course that many of the inventive features of this description can also be used for packing a large range of other types of objects. Thus, the invention shall in no way be considered to be limited to the packaging of hams. Although the components, in the preferred embodiment of the apparatus described and illustrated, are linked together and mutually act to provide a fully automatic device for filling bags, pumping out the bags, crimping the bags, and shrinking the bags, it is intended that the present invention should include within its scope the use of one or more possible components of the inventive apparatus with other conventional components. E.g. can the bag filling unit in fig. 1 and 2 are used in conjunction with any other different type of bag pumping and clamping device, and/or other forms of shrinking device. Likewise, the vacuum chamber in fig. 3 and 4 are used together with an alternative arrangement of the feeding system and shrink tank.

Claims (6)

1. Apparatus for; vacuum packaging where a filled bag with an unassembled bag neck is fed. efcivacuum chamber. which is then closed to empty the interior of the bag and the exterior of a clamp is placed to close the neck of the bag, kara k<*>..t;,"e.;r i s' e r t . w e d a pair of opposing r gap-defining members (24, 32) which or fitted together parallel for movement towards and away from each other to define an elongated slot for partial constriction of the bag neck, a pair of collecting means (33) which are movable towards and away from each other along paths parallel to the gap-defining means (24, 32), and a conveyor (21, 22) which determines the feeding path of an object and which passes between the gap-defining means ( 24, 32) reach these cr in their strongly separated positions. 2. Apparatus as set forth in claim 1, characterized in that the gap-defining members (24, 32) are horizontal bars which extend across the direction of the object, feed path and are mounted for movement between a separate position, in which the lower slit-defining member (24) is just below the nuitebano of the object and the upper slit-defining member (32) is strongly separated from and above the web to allow an object to pass between the lower and upper members, and a slit-defining position in which the upper the body (32) has been lowered to ,. lie closely adjacent, but just above the lower gap-defining member (24), and that the collecting members are sticks or the like which extend vertically and are movable horizontally towards and away from each other between an open position and a closed position in which they are. separated from each other, to a small extent to completely restrict the neck of a filled bag' on the feed conveyor. 3. Apparatus as set forth in claim 2, characterized in that two side-by-side conveyors (21, 22) are provided to allow a pair of "filled" bags to be fed simultaneously into the vacuum chamber in side-by-side relationship, that each of the gap-defining members (24,-: 32) is (.long enough to extend over the double: width-; ofV the conveyors' f of1 to act simultaneously on two filled bags in the chamber to partially collect the necks of these filled bags, that there are two parallel conveyors (19, 20] arranged side by side to feed two filled bags simultaneously to the conveyors (21, 22) in the chamber, that a push member (8b) is arranged to feed one of the conveyors (20), and that a transfer carrier (18) is driven to alternately transfer objects that arrive on said one of the parallel conveyors, so that the two parallel side-by-side conveyors (19, 20) can be activated simultaneously after delivery of a further filled bag on said one conveyor (20). 4. Apparatus as set forth in claim 2 or 3, characterized in that the conveyor (22) is in the form of a support table to hold the bag during the collecting and clamping operation and is movable between an upright object receiving position and a lowered bag closing position, and that the lower slit-defining member ( 24) is a roller which is placed at the entrance end of the support table (22). 5. Apparatus as stated in claim 4, characterized by an adjustment means for adjusting the level of the clamping position for the support table to thus allow adjustment to be able to accommodate a changed object height. 6. Apparatus as stated in any one of the preceding claims, characterized by a per se known clamping device (30, 35) for applying a clamp around the combined bag neck between the collection members (33) and the gap-defining members (24, 32), and opposite clamp receiving slots in the collecting means (33) which in the closed position of said collecting means define a clamping guide along which a clamp (36) can pass during the clamping operation so that the clamp will be fed into the assembled bag neck during the clamping operation.