US3619979A

US3619979A - Packaging machine

Info

Publication number: US3619979A
Application number: US867324A
Authority: US
Inventors: Kjell Halvard Martensson; Lars Anders Karlsson
Original assignee: Tetra Pak AB
Current assignee: Tetra Pak AB
Priority date: 1968-10-30
Filing date: 1969-10-17
Publication date: 1971-11-16
Anticipated expiration: 1988-11-16
Also published as: GB1292821A; CH518832A; DE1953727C3; NL167378C; JPS4918755B1; ES196475Y; DE1953727A1; FI47970C; JPS4918754B1; NO124984B; BR6913776D0; FI47970B; SE335090B; NO130052B; ES392874A1; ES372988A1; ES196475U; JPS4945359B1; ES392875A1; DK135665B

Abstract

A MACHINE FOR ERECTING, FORMING AND SEALING PACKAGE CONTAINERS FOR PRODUCTS SUCH AS MILK IN WHICH DIFFERENT SIZED PACKAGES MAY BE EMPLOYED AND IN WHICH VARIOUS ELEMENTS OF THE MACHINE MAY BE ADJUSTED OR ALTERED TO ACCOMMODATE THE DIFFERENT SIZED PACKAGE CONTAINERS.

Description

16, 1971 K. H. MARTENSSON EIAL 3,619,919

PACKAGING MACHINE 'F'iled Oct. 17, 1969 9 Sheets-Sheet 1 Nov. 16, 1971 MARTENSSON ETAL 3,619,979

PACKAGING MACHINE 9 Sheets-Sheet 2 Filed 001;. 17, 1969 9-Sheets-Sheet 5 PACKAGING MACHINE Fig. 3

K. H. MARTENSSON ET AL Nov. 16, 1971 Filed Oct. 17; 1969 K. H. MARTENSSON EI'AL 3,619,979

Nov. 16, 1971 PACKAGING MACHINE 9 Sheets-Sheet 4.

Filed 001;. 17, 1969 Nov. 16, 1971 K. H. MARTENSSON EFAL 3,619,979

PACKAGING MACHINE Filed Oct. 17-. 1969 '9 Sheets-Sheet 5 Fig.4

Nov. 16, 1971 K. H. MARTENSSON ETA!- 3,619,979

PACKAGING MACHINE Filed 0011. 17, 1969 9 sh86tSSh88t 6 Nov. 16, 1971 K. H. MARTENSSON EFAL 3,619,979

PACKAGING MACHINE Filed Oct. 17, 1969 9 Sheets-Sheet '7 Nov. 16, 1971 Filed Oct. 17, 1969 K. H. MARTENSSON AL PACKAGING MACHINE 9 Sheets-Sheet 8 Nov. 16, 1971 K. H. MARTENSSON ETAL- 3,619,979

7 PACKAGING MACHINE Filed Oct. 17, 1969 9 Sheets-Sheet 9 United States Patent US. Cl. 53186 16 Claims ABSTRACT OF THE DISCLOSURE A machine for erecting, forming, filling and sealing package containers for products such as milk in which different sized packages may be employed and in which various elements of the machine may be adjusted or altered to accommodate the different sized package containers.

This invention relates to a packaging machine for the production of filled and sealed packages from pre-produced blanks of a thermoplastic-coated material, e.g. plastic-coated cardboard, provided with fold lines to facilitate folding, comprising an intermittently rotatable mandrel Wheel carrying mandrels, equipment for raising up the container blanks into the shape of a tube and for placing the raised-up containers onto the mandrels, equipment for the forming and sealing of a bottom on the container blanks placed onto the mandrels, a conveyor fitted with holders that can be moved, preferably in the horizontal plane, equipment for moving the container blanks processed and fitted with bottoms on the mandrels, to the holders in the said conveyor, and equipment for pre-folding, filling and sealing of the containers carried along in the said holders.

Packages of the gable-top type have been used for a long time in packaging technology. These are almost always manufactured from pre-produced blanks which are provided with a suitable fold-line pattern in order to facilitate raising-up and forming of the packages by folding the areas forming the top and bottom respectively down into their final positions. The said container blanks are nowadays most often coated with a thermoplastic material such as polythene, the thermoplastic layer being utilised both for making the package liquid-tight and for sealing the package by the application of heat and pressure so that it is secured in the raised position.

The above packages have found their most important use as packages for liquids and particularly"for milk, and various machines have been designed for manufacturing these packages. One drawback of all known packaging machines of this type is that they cannot be changed over from one package size to another. There have been cases of two or more machines, designed for different package sizes, being combined on the same machine foundation, but the savings made in this Way have been insignificant since in principle all the machine elements have to be duplicated.

The need for a packaging machine that can be converted for different package sizes is particularly great as far as small and medium-sized dairies are concerned since it is far too expensive to purchase a number of packaging machines. The above drawbacks of known packaging machines are avoided by means of the machine in accordance with this invention, which is characterised by the mandrel wheel having two different sets of mandrels of different cross sectional areas each set comprising 11, number of mandrels; by the mandrel wheel being designed to be rotated intermittently between dif- Patented Nov. 16, 1971 ferent positions, both by an angle equal to 360/n which rotational angle corresponds to the normal indexing angle when the machine is in operation, and by an angle equal to 360/2n which rotational angle corresponds to the angular displacement necessary when changing mandrel sets.

A particularly advantageous constructional version of the invention will be described below with the aid of the attached diagrammatic drawings, of which FIG. 1 shows a perspective view of the machine,

FIG. 2 shows a side elevation of the machine,

FIGS. 3 and 3a show cross sections of the mandrel wheel,

FIGS. 4 and 4a show the mandrel wheel with various items of interacting equipment,

FIGS. 5 and 5a show a detail of a press unit and associated pressure relieving mechanism,

FIG. 6 shows a partial section of a puller mechanism, and

FIG. 7 shows a container blank.

With the packaging machine in accordance with the invention, packages are manufactured from pre-produced container blanks made from thermoplastic-coated cardboard or similar material. An example of such a container blank is shown in FIG. 7, in which the container blank 4, which is initially fiat, has been raised up to form a tube with a square section. Production of the packaging blank 4 is accomplished by a sheet of plastic-coated cardboard, after the application of pressure if necessary, being pressed out along the desired shape and provided with fold lines 103 which facilitate folding of the container blank. After the cardboard blank has been pressed out, its two longitudinal edges are united in a longitudinal joint :104 which makes possible raising-up of the blank into the shape of a tube.

The bottom end 35 of the container blank 4 exhibits two larger rectangular

bottom end areas

105 and 106, as well as two smaller triangular

bottom end areas

107 and 108, which through the fold-

back areas

109 and 110 are joined to the

larger flaps

105 and 106. All the said end areas are separated from one another and from the container body 111 by means of the fold lines 103 provided in the packaging material in order to facilitate folding.

The top portion 113' of the container blank exhibits much the same folding pattern as the bottom portion, but since the top portion is not to be folded in such a way as to produce a flat top but a gable top, the dimensions of the areas forming the top are different.

The areas 113 forming the top are in addition joined to scaling areas 112 which are designed to be brought together to form a flat fin, in which the sealing areas have been sealed to one another so as to form a leakproof and durable joint.

Both the top and bottom portions are formed in the same general manner, but for the sake of simplicity only the folding operation used for the bottom portion will be described here, which folding is accomplished by the smaller

triangular areas

107 and 108 being folded in over the opening of the container blank, after which the

larger flaps

105 and 106 are also folded in over the opening of the container blank, and at the same time the fold-

back flaps

109 and 110 are folded in against the triangular flaps, so as to be situated at the conclusion of the folding operation between, and in contact with, the larger and smaller flaps, in which position the flaps are sealed to one another with the aid of heat and pressure.

As has been pointed out before, the top portion of the package is formed in the same general Way, but with the difference that the areas forming the top, by virtue of their dimensions, cannot be folded in completely over the opening of the container, but only to a position in which the opposing pairs of areas meet each other. The sealing areas 112 are folded against one another to form a fiat fin, the smaller sealing areas being folded in, concertinafashion, between the larger ones.

For the sake of clarity, a general specification of the packaging machine will be given below first, mainly by reference to FIGS. 1 and 2, after which certain constructional components or elements of the machine, which in accordance with the invention are characteristic for the machine and interact with one another, will be specified in greater detail.

GENERAL SPECIFICATION OF THE MACHINE The fiat container blanks 1, which have not yet been raised up, are taken out of the storage unit 2, and at the same time the container blanks are formed into a tube 4 which in this case has a square section.

By means of the pusher unit 3, which consists of a rotatable chain fitted with carriers 9, the raised-up container blanks 4 are pushed onto a mandrel 5 situated on a mandrel wheel 6 which has been brought into position in front of the pusher unit. (This position is denoted on the drawing by I.) After the container blank 4 has been placed onto the mandrel 5, the mandrel wheel 6 indexes to the next stop, and since the indexing angle in this case is 60, this means that the mandrel wheel rotates 60 anticlockwise to the position II, after which the mandrel wheel again stops.

In the position II, the bottom portion 35 of the container blank 4 placed onto the mandrel 5 is situated right in front of a pre-folder unit 7 actuated by an operating unit 30, preferably a pneumatic cylinder. With the aid of the control unit 30, the pre-folded unit 7 is moved up to the bottom portion 35 of the container blank 4 protruding from the mandrel 5, whereupon the leaves of the pre-folder unit 7 are folded in against the bottom portion of the container blank, in order to pre-fold or soften up the previously provided fold lines situated in the bottom portion of the container blank 4. Pre-folding is however stopped before the wall areas of the container blank, which are to form the bottom, have been folded right into their final positions, and, owing to the elasticity of the material, the portion 35 of the container blank 4 protruding from the mandrel 5 will regain the same general position which it had before the pre-folding operation.

When the pre-folding operation has been completed, the mandrel wheel 6 again indexes, and stops in position III, in which position the pre-folded end portion 35 of the container blank is situated right in front of a heating device 8 which can be raised and lowered. By lowering the heating device 8 down into the raised-up bottom portion 35 of the container blank 4 and blowing a hot gas, preferably air, against the outer parts of the end portion which are intended to act as sealing areas, the thermoplastic coating on these parts is heated to such an extent that the thermoplastic coating softens. When sufficient heating of the sealing areas of the end portion 35 has been achieved, the heating device 8 is raised to a position outside the opening of the end portion 35, after which the mandrel wheel 6 can continue its indexing to position IV.

While the mandrel wheel 6 with the mandrels 5 moves on from position III to position IV, the portion 35 of the container blank 4 protruding from the mandrel 5 comes into contact with a guide rail arrangement 36 which guides two

opposite sides

105 and 106 of the end wall area of the container blank 4 towards one another, while the remaining

end wall areas

107 and 108 are folded in, concertina-fashion, between the first-mentioned end wall areas. When the mandrel 5 has reached position IV, a pressure plate 10 actuated by an operating unit 29, preferably a pneumatic cylinder, is pressed onto the folded-up bottom area, as a result of which a largely fiat container bottom is formed. By virtue of the fact that the heated-up parts of the bottom portion 35 are cooled down at the same time as the areas of the container blank 4, which form the bottom, are pressed together between the pressure plate 10 and the end piece of the mandrel 5, the heated-up thermoplastic layers, once the heated-up surfaces have been joined by surface fusion, and the areas forming the bottom are thus held together in the compressed position, are caused to form a flat liquid-tight bottom. In order to ensure satisfactory leakproofness, it is essential that the folded-up bottom areas should be pressed against one another with a great force, and press forces up to several tons are recommended since press forces of this magnitude cause satisfactory flow of the plastic material to take place in the sealing area and thereby sealing of any leakage channels which may have been formed at the joint between the overlapping layers of material.

When compression of the bottom, has been completed, the mandrel wheel indexes on to position V, in which position there is no working operation to be carried out, and the container 33, which has been provided with a bottom, is therefore moved on after a period of time corresponding to an indexing interval to position VI in which the mandrel 5 points vertically downwards.

In position VI, the container 33 is drawn off the mandrel 5 with the aid of a puller 11 that can be moved vertically, the front end of which is fitted with a suction cup 37 which can be connected to a source of vacuum not shown here.

The pulling-off operation is carried out by the puller 11 being raised by an operating unit 38, e.g. a pneumatic cylinder, to a position such that the suction cup 37 comes into contact with the fiat bottom of the container 33. When the suction cup 37 has made contact with the bottom, or before this contact has been established, the suction cup is connected to a source of vacuum that is not shown here, which means that the suction cu attached itself firmly to the bottom of the container 33. When the puller 11 is now given a downward movement, the container 33 is drawn off the mandrel 5 and is lowered in between holders fitted onto an intermittently moving chain conveyor 13, by means of which the container 33 removed from the mandrel wheel 6 is given a mainly horizontal travelling motion.

After completion of the pulling-off operation, the mandrel wheel 6 indexes to position I, in which position a new container blank 4 is placed onto the mandrel 5 by means of the pusher unit 3.

The procedure during the time that one mandrel describes a complete indexing cycle has been described above, but naturally working operations are carried out simultaneously in all positions during every indexing interval, with the exception of position V, which means that a completely processed container 33 is drawn off during each indexing interval and a new container blank is at the same time placed onto a mandrel 5. The time between two subsequent indexing movements must naturally be adjusted in such a way that there is time for the various working operations at the various positions to be completed.

The conveyor 13 consists of two parallel endless chains fitted with holders 97, pairs of holders situated opposite each other on the two chains forming between them a space 98 such that a container 33 can be placed into it upright. When a container 33 is drawn off the mandrel 5 by means of the puller 11 and is moved downwards, it is inserted between the two chains 13 and into the space 98 defined by the holders 97. In order that this should be feasible, movement of the conveyor chain must naturally be synchronised with that of the mandrel wheel, so that the conveyor chain 13 moves forward one holder division for each indexing of the mandrel wheel 6, and also in such a way that there is always a new and empty space defined by the said holder elements 97, right underneath the mandrel 5 when this is in position VI.

When the container 33 has been inserted into the space defined by the holders 97, the suction cup 37 releases its hold and is disengaged from the container 33 which is now in position between the holders 97 connected to the conveyor chain 13. As mentioned above, the conveyor chain is moved intermittently to the left in FIGS. 1 and 2 for each indexing of the wheel, the level of the containers 33 being determined by the fact that their bottoms slide along a track 12.

In position A, the top part of the container 33 is prefolded by a pre-folder 14 affixed to a yoke 25 which can be raised and lowered. Pre-folding is effected by triangular leaves 40, incorporated in the pre-folder 14, being folded in against two opposite triangular side areas of the top part 41, the remaining side areas being at the same time folded in over the opening of the container and locating between themselves the said triangular areas. The prefolding operation is however only intended to pre-fold or soften up the fold line pattern produced on the container blank in advance, with the aim of defining the fold pattern required to form the top closure of the container, and the pre-folding operation is therefore not completed, the pro-folder 14 being raised to its upper position when the fold pattern has been pre-folded.

In position B, which in the example shown is situated a container holder division away from position A, the opening of the container 33 is expanded by means of an expander 15, which opening has been somewhat reduced in area during the pre-folding operation, as a result of the fact that the top areas of the container 33 do not completely return to their initial positions. During the operation at position B, the downwardly-pointing expander 15 fitted to the yoke 25, by means of the wings 42 attached to the expander 15, presses against the inside of the top portion 41 during the downward motion of the expander, so that this is largely returned to the position it was in before the pre-folding operation.

The pre-folder 14 and the expander 15 may with advantage be placed on a common yoke 25, which may in turn be connected with an operating rod 43 common to both the units 14 and 15, the vertical movements of the rod 43 being steered by a cam 31 fitted onto the drive shaft.

After another indexing of the mandrel wheel 6 and a lateral movement of the conveyor chain 13, the prefolded container 33 is at position C, i.e. right underneath the filling unit 16, through the agency of which is a preset quantity of liquid is poured into the container, after which the filled container, intermittently and synchronously with the indexing mechanism, is moved to position D, where the opening of the container is situated right underneath the top heating unit or top oven 17. The top heating unit 17, like the bottom heating unit 8, consists of heating elements provided with holes, hot air being blown through the said holes which are arranged in such a pattern that heat is only supplied to those parts of the top area 41 which are to be sealed to one another. Hot air is obtained by burning gas in a special combustion chamber 28, after which air is blown through the combustion chamber and out through the holes on the heating elements. Heating of the sealing areas at the top part 41 of the container 33 is accomplished by the top heating unit 17 being lowered into and over the top part of the container 33, so that the heated air blown out through the said holes largely impinges on the thermoplastic-coated sealing areas at right angles. The thermoplastic material is quickly heated up to its softening temperature, after which the top heating unit 17 is raised to a point outside the opening of the container 33, after which the container is moved from position D to position E, the sealing areas of the top part 41 being simultaneously folded in over the opening of the container with the aid of the guide rails 114. Folding-in of the top part 41 of the container 33 is effected by the said triangular areas being folded in, Concertina-fashion, between the outer areas forming the top, in such a way that the sealing areas are brought together into a fin, which in position E is compressed between two interacting compression blocks 18, which are cooled. By virtue of the fact that the plastic is hot at the start of the sealing operation, surface fusion takes place between the heated plastic layers that have been brought together, which means that the seal obtained after compression and cooling at position E will be very strong. Another position F may be provided beyond position E, in which position labelling, date stamping or similar operations can be carried out with the aid of a stamping mechanism, marking mechanism, labelling machine or similar.

At position G at the end 19 of the conveyor chain, the holders which have been surrounding the container during its travel in the chain 13 are separated and the completed package is released from the packaging machine.

The packaging machine is powered by an electric motor 20 with a directly-coupled gear box of e.g. the worm or spur gearing type, the output shaft of which is denoted 44. On the output shaft 44, there is fitted by means of a sliding clutch a chain wheel 45, which drives through a chain another chain wheel 46 that is fitted on the input shaft 48 of bevel gearing 47. On the same shaft 48, there is fitted another chain wheel 49 which through a chain drives a chain wheel 51 fitted on the input shaft 50 of the indexing gear 23 of the mandrel wheel 6.

The output shaft 52 of the bevel gearing 47 carries a chain wheel 54 which through a chain transmission drives cams that govern the movements of the filling unit 16 and also operate the reciprocating pump forming part of the filling unit.

There is furthermore a chain transmission connected to the shaft 52 which drives the pusher unit 3.

The main shaft 21 from the bevel gearing 47 carries cams, one set 31 for driving and governing the vertical movements of the operating rod 43 and thereby also for operating the pre-folder 14 and the expander 15, the other set 32 for driving and governing the movements of the top heating device 17. The main shaft 21 also actuates an indexing gear 24 which drives the chain conveyor 13.

Apart from the driving operations obtained from the motor 20, a number of movements are carried out with the aid of pneumatic or hydraulic cylinders, as has been referred to before. The flat container blanks 1 are thus taken out of the storage unit 2 and formed into a tube with the aid of suction cups, which are capable of swivelling, fitted to an arm 115, the swivelling motion of which may e.g. be obtained with the aid of a pneumatic cylinder. The operations along the mandrel Wheel are also carried out by items of equipment which are actuated or governed by pneumatic cylinders, and there is a separate pneumatic cylinder fitted to lift the top sealing oven 17 to a position further away from the container 33 than the upper position which can be reached by the cam 32, in the event of breakdowns or when the machine is stopped. Further equiment that is driven separately and with the aid of pneumatic cylinders are the sealing blocks 18 and possibly also the marking unit 34.

The above specification of the packaging machine and its means of driving will have given a general idea of its working. As has been mentioned in the introduction, the machine described can be changed over from one size of package to another, and it is therefore to a certain extent fitted with duplicate equipment.

If we assume that the machine is to be equipped for the production of packages with a capacity of 2 litres and 1 litre respectively, the packages will be given the same height while their cross sectional areas will be different. The machine described is constructed for packaging containers with a square bottom section, but other bottom sections also can naturally be used, with the principle remaining unchanged.

The items of equipment or parts of the machine which must be made convertible or easy to replace are e.g. the

storage unit 2, the guide rails 53 of which must be arranged so that the flattened container blanks 1 are guided between the rails. In the machine specified here, the storage unit has been made convertible by virtue of the fact that the guide rails 53 can be lifted up and lowered again into one of two positions corresponding to the desired package size. Some of the rails are furthermore fitted in a guide with elongated holes, by which means the guide rails can be moved between an inner and an outer position of the said elongated holes.

When the size of package is changed, the mandrel wheel must also be converted in such a way that the duplicate mandrel set 5', which has dimensions to fit the new package size, is brought into position right in front of the pusher unit 3.

Since both the fold pattern and the opening area of the new container blanks are different when the size of package is changed, the pre-folder unit 7 at position 11 and the heating device 8 at position III must be changed. This may be done simply by duplicating the equipment for units 7 and 8 and mounting these on retractable or rotatable devices, so that the pre-folder unit and the heating device which fit the container blanks being used can be easily brought into position right in front of the mandrels 5.

The conveyor chain 13 must naturally contain duplicate holders and the conveyor chain 13 must in addition be rendered adjustable in such a way that the holder which fits the container blank being used can be brought right underneath the mandrel 5' in position VI. Once the mandrel wheel has been moved on and the conveyor chain 13 re-positioned so that the mandrels 5' and the holders which fit the new container blanks will be correctly positioned, no further adjustment will be required since the indexing intervals, the indexing angle of the mandrel wheel 6 and the feed movement intervals of the conveyor chain 13 remain unchanged.

The pre-folder 14, expander 15 and the heating unit 17 must naturally be changed over for the same reason as that which necessitates changing of the corresponding parts on the mandrel wheel 6. Change-over of units 14, 15 and 17 is effected in the simplest manner by duplicating the units and mounting them on a retractable or rotatable arm which allows the appropriate unit to be placed into the operating position manually.

The filling unit 16 can also be made exchangeable, even if this does not appear to be absolutely necessary. It is however necessary to alter the stroke of the reciprocating pump or to fit a duplicate pump, since the packages are not intended to be filled with the same quantity of liquid.

The packaging machine in accordance with the specification has been found particularly reliable in operation and is in addition considerably cheaper than known machines, which, if they are to be capable of use for different sizes of package, must largely be duplicated with the exception of the actual machine foundation.

It is naturally possible to use e.g. hydraulic cylinders or electromagnetic power units instead of pneumatic cylinders, but we have found that pneumatic cylinders produce a fast and sure movement and they are in addition easy to operate.

After this introductory general specification of the operation of the packaging machine, a more detailed specification will be given below of certain units of vital importance for the packaging machine, and the way in which these interact in order to achieve the desired result, namely a cheap, fast and convertible packaging machine which in addition exhibits good operational characteristics.

(PARTICULAR MACHINE SPECIFICATION Since the mandrel wheel 6 and the items of equipment interacting with the mandrel wheel are a vital part of the machine in accordance with the invention, the mandrel wheel will be made the subject below of a particular and more detailed specification. The design of a mandrel wheel 6 shown in FIG. 3 comprises a hub 56 which can be freely rotated on the driving shaft 54. On the hub 56, there are fitted a number, in the present case twelve, mandrels which are divided into two mandrel sets denoted 5 and 5'. The mandrel sets 5 and 5' each contain six mandrels which are identical. The mandrels in the two sets are the same length but differ in that e.g. they have different cross sectional areas. The mandrels in the two sets are naturally suited to packaging containers of different size, and the mandrel wheel 6 is arranged so that either one or the other mandrel set may be brought into the working position, while the mandrel set which is not in the working position is caused to passively rotate with the mandrel wheel 6 during its rotation.

A ring 63 is aflixed to the hub 56 of the mandrel wheel 6 by means of bolts 64, which ring exhibits a number of connector seats 67 which are also divided into two sets, one set of connector seats having an angular displacement of 30 in relation to the other set of connector seats, all measured from the centre of rotation of the mandrel wheel.

On the head 62 of the shaft 54, there is fitted a disc 72 which is firmly secured to the driving shaft and exhibits a number of locating slots 66 as well as connectors 65 fitted into these slots, which connectors have the shape of elongated bodies or pins with rounded or chamfered ends. It is also possible to use balls as connectors, but since the locating slots must have a certain length for reasons of strength, the balls which must have a diameter larger than the legnth of the locating slots will have unnecessarily large dimensions.

The locating slots 66 on the disc 72 are placed so that they coincide with either of the said connector seat sets 67. The number of locating slots 66 is thus equal to half the number of connector seats 67 and since in this case the disc 72 is provided with four locating slots, each set of connector seats will contain four sets. The disc 72 and thereby the driving shaft 54 can be connected to the mandrel wheel by connectors 65, which are placed in the locating slots 66, being fitted into one of the sets of connector seats, and by moving the position of the connectors from one to the other of these sets of connector seats 67, the mandrel wheel 6 can thus be given an angular displacement, relative to the shaft 54, of 30.

In order to retain the connectors 65 in position inside the connector seats 67, the connectors are pressed against the seats 67 by means of the pressure plate 73 which is fitted on the hub 78 of the disc 72, and which is pressed against the ends of the connectors 65 protruding from the locating slots 66 by a compression spring 57. In order to retain the spring in position and to make possible adjustment of the spring force, a thrust washer 60 is fitted on the shaft head 62. The thrust washer 60, onto which one end of the spring 57 abuts, is held in position by a nut 58, and the disc 72 which is wedged onto the shaft head 62 is secured to this in the axial direction by the nut 59. The driving shaft 54 further exhibits a cooling duct 79 drilled in the axial direction, which through radial ducts 63 is in communication with annular grooves 81 situated 1n the hub 56 of the mandrel wheel. From the annular grooves 81, cooling ducts radiate outwards through the hub 56, which cooling ducts are in connection with the cooling ducts 55 situated inside the mandrels 5.

In order to prevent leakage, there are sealing rings 82 fitted on both sides of the annular grooves 81. Coolant is supplied through the end 68 of the shaft head 62 and is caused to circulate through the mandrels 5 with a view to removing the heat transmitted to the container blanks in conjunction with the sealing operation.

When the driving shaft 54 is rotated during the indexing process, the mandrel Wheel 6 is rotated along with the shaft, since the hub 56 of the mandrel wheel is connected to the driving shaft by means of the connections 65. If there should arise some obstacle to the rotation of the mandrel wheel, e.g. a faultily formed container or something similar, the mandrel wheel 6 should be disengaged since the mandrels may otherwise be damaged through being deformed. This disengagement takes place automatically, through the connectors 65 being forced out of seats 67 in the event of the force transmitted between the mandrel wheel and the disc 72 becoming excessive, and being pressed against the pressure plate 73 so that this is displaced from the disc 72 against the spring force exerted by the spring 57. The connectors 65, if the force transmitted is excessive, can therefore leave their seats 67., from which they will be automatically displaced owing to the conical or rounded shape of the end of the connectors. When the connectors 65 have been forced from the connector seats 67, the mandrel wheel hub 56 is disengaged and the mandrel wheel 6 ceases to rotate along with the driving shaft 54. Since in most cases the obstacle causing disengagement remains, it is not desirable that the connectors 65 should slide along the disc 72 and drop into a connector seat 67, only to be forced out again, every time they pass a seat. In order to prevent this happening, the machine is equipped with a sensor unit 69 shown in FIG. 4, which may be a micro-interruptor or an air valve, which detects the position of the pressure plate 73 by means of a sensor arm, and which, if the pressure plate is moved towards the left as a result of its having become disengaged, actuates an operator 70 e.g. an air valve, which in turn operates a lever 71 that moves away the pressure plate 73 against the spring force and thus definitely disengages the mandrel wheel 6. The valve 69 can naturally also transmit an impulse to a relay which switches off the current to the driving motor and thus stops the machine.

In position [[V, the pressure plate 10, as described earlier, is pressed against the top side of the mandrel 5 in order to seal the folded-up bottom flaps 35 of the container blank 4. Since the compressive force on the mandrel 5 and thereby on the driving shaft 54 of the mandrel wheel 6 will be considerable, steps have been taken in the present design to prevent excessive stresses and consequent deformation of the driving shaft. The steps taken to prevent the driving shaft 54 being subjected to excessive stress are described by reference to FIG. 5 which shows a detail of the pressure unit 10 and associated equipment.

As will be seen in FIG. 5, there is a frame 89 attached to the machine framing 88. The frame 89 is furthermore firmly secured to two carrier plates 90, each of which at their ends have resilient units 87 of the type shown in FIG. 5a.

The resilient unit 87 consists in. principle of a rubber ring element 92 which is retained between a hole in the carrier plate 90 and the shaft 91 connecting pairs of resilient units 87. In order that the rubber elements 92 should be retained in position, they are located both by spacer sleeves 96 and locating washers 95, which are in turn held in the intended position with the aid of washers 94.

The shafts 911 are joined to both the pneumatic cylinder 29, by means of which the pressure plate is operated, and to the rods 84 which take up the force, which are in addition joined to one another by a yoke 85 that passes round the hub of the mandrel wheel 6, while allowing some clearance between the yoke and the hub, so that rotational movement of the latter should not be prevented. The rods taking up the force are connected to the carrier plates 90 by means of a fixture 86, and the positions of the rods 84 and thereby also that of the yoke 85, in relation to the hub of the mandrel wheel, can be adjusted by means of the nuts 93.

The method of operation of the equipment is as follows:

When the mandrel wheel 6 has completed its indexing movement and a mandrel 5 with a container blank on it has been brought into position IV, an impulse is delivered to the pneumatic cylinder 29 by a programming device, not shown here, which may conveniently consist of a cam disc, causing the cylinder to push the pressure plate 10 down to the top side of the mandrel 5, whereby the heated and pre-folded bottom portion 35 of the container blank 4 is completely folded and compressed between the pressure plate 10 and the mandrel. Since, as has been mentioned previously, the compressive force transmitted by the pressure plate 10 is very large, the reaction from the mandrel 5 will force the pressure plate 10 and the pneumatic cylinder 29 against the direction of compression, i.e. away from the mandrel. If the pneumatic cylinder 29 were rigidly fixed to the machine base 88, the above reaction force would only be transmitted to this, without the pneumatic cylinder being moved out of its position, and the mandrel wheel shaft 54 would have to absorb the whole compressive force. Since, however, the pneumatic cylinder 29 is fixed to the carrier plate 90 connected to the machine base 88 in a resilient manner, the pressure plate 10 and the pneumatic cylinder 29 can move away somewhat through the rubber element 92 being compressed, which also means that the shaft 91 and the rods 84, which take up the force, are displaced somewhat in a direction away from the mandrel 5.

After the rods 84 have been displaced somewhat (in the present case about 0.25 mm.), yoke comes in contact with the hub of the mandrel wheel 6, thus preventing further elastic movement of the pneumatic cylinder 29, pressure plate 10 and the rods 84, which take up the force, away from the mandrel. The shaft 54 of the mandrel wheel 6, during the initial stage, before contact has been reached between the yoke 85 and the mandrel wheel hub, is subjected to a load of the same magnitude as the force exerted by the pressure plate 10 against the top side of mandrel 5, but when the yoke 85 comes into contact with the hub of the mandrel wheel, the force from the pressure plate 10 is transmitted, by way of the mandrel 5, the mandrel wheel hub and the yoke 85, to the tension rods 84 which, by virtue of the fact that they are firmly secured to the pneumatic cylinder 29, form a closed force system of which the shaft of the mandrel wheel does not form a part, an dthe shaft will not therefore be subjected to load.

The mandrels 5 attached to the mandrel wheel 6 are divided into two

groups

5 and 5, as has been mentioned before. In the figure, mandrels 5 have a larger cross sectional area than the mandrel 5', and the mandrels 5 are all so oriented in relation to the mandrel wheel 6 that their central axes, when produced, intersect at points which coincides with the centre of rotation of the mandrel wheel. The mandrels 5 thus project radially from the mandrel wheel 6. Since as little adjustment work as possible is to be carried out when mandrel sets are being changed over, the arrangement chosen is such that the side edges of the mandrels 5 and 5', which are the rear edges when seen in the direction of rotation, have the same positions in both sets of mandrels. This means that the feed table near the pusher unit 3 need not be adjusted when the size of package is changed, and that in position VI the side of the mandrel, which is turned towards the container track 12, is always in the same position relative to the near end of the container track, regardless of which mandrel set is being used.

In order to achieve this, the mandrels in the set 5' must be positioned asymmetrically in relation to the centre of rotation of the mandrel wheel, i.e. the central axes of the smaller mandrels 5, when produced, do not all intersect at one and the same point, nor do they pass through the centre of rotation of the mandrel wheel 6.

Account must naturally be taken of the asymmetrical positioning of the smaller mandrels 5 when locating the pre-folding equipment in position II and the heating unit in position III, but this adjustment is no appreciable problem since the said units are nevertheless duplicated and are arranged in such a way that they are swung or displaced between two positions, ie a working position and a non-working position. The holders 98 in the chain conveyor 13 must also be located in such a way that they are suited to the placing of the mandrels 5 on the mandrel Wheel 6. The smaller holders 98 thus cannot be placed exactly between the larger holders, since the

mandrels

5 and 5 have different widths, and it is only the edges of mandrels S and 5', which are the rear edges when seen in the direction of movement, that have the same position in position VI. This means that the edges of the holders, which are the front edges when seen in the direction of movement, will be spaced equally on the chain conveyor 13, and that the conveyor moves forward a distance corresponding to two divisions for every indexing movement of the mandrel wheel 6. The reason why the feed movement is two divisions is naturally that every other holder 98 belongs to the same holder set and thus takes place in the operation, while every other holder belongs to the holder set which is not used.

The holders within each holder set must naturally be arranged at an even spacing, and when changing over the packaging machine from one size of package to the other,

care must be taken that the chain conveyor 13 is displaced so that the holders 98 in the holder set being used corre spond to the positions of the mandrels 5 in position VI.

The holders 98 are formed by angle-section holder elements 97 which are attached to two interacting endless chains running between chain wheels 99. The holder elements in the sides 100 of the chains, which are turned towards one another, together form a space that is the same size as, or somewhat larger than, the cross section of the container 33. Since the containers may have two different sizes, every other holder is smaller and every other one larger. The positions of the holders 98 are adjusted when a change is made from one size of package to the other by the chain wheels 99 being turned, and the chain wheels 99 may in addition be fitted with advantage with a disengagement device of the same kind as the one already described in connection with the specification of the mandrel wheel 6.

The puller device shown in FIG. 6 consists, as mentioned before, of a suction cup 37 made from an elastic material, which through a duct 75 is in communication with a valve 76, which connects the duct 75 either with a source of vacuum or the ambient atmosphere, or with a source of compressed air, depending on the position of the control arm 77 of the valve 76. The suction cup 37 is attached to a pusher rod 74 which is connected to, or is the piston rod of, a pneumatic cylinder 38. The pneumatic cylinder 38 is operated by a valve that is not shown here, which is most conveniently operated by a cam disc,

and the pneumatic cylinder 38 must naturally work synchronously with the indexing wheel 6.

The valve 76 is designed so that its position in relation to the container track 12 can be adjusted, and the control arm 77 of the valve 76 is designed to be capable of being actuated by the pusher rod 74 or by a unit 101 connected to the pusher rod. When the control arm 77 is not actuated by the unit 101, the duct 75 is connected to a source of vacuum through the valve 76, but when the control arm 77 is actuated by the unit 101, the duct 75 is connected to the ambient atmosphere.

The method of operation of the puller device is as follows:

When a mandrel 5 has indexed to position VI, the pusher rod 74 is lifted up by the pneumatic cylinder 38 until the suction cup 37 is pressed against the bottom of a container 33 situated on the mandrel 5. In this position, the duct 75 is in communication with a source of vacuum and the suction cup will thus be clamped onto the bottom of the container 33.

When the pusher rod, driven by the pneumatic cylinder 38, is thereafter moved downwards, the container 33 is drawn off the mandrel 5 and into a holder 98 which is situated directly underneath the mandrel 5. When the unit or rod 101 connected to the pusher rod 74, during e dO I WaId stroke, comes into contact with the control 12 arm 77 of the valve 76, the suction cup 37 is placed in communication with the ambient atmosphere or with a source of compressed air through the duct 75, which means that the suction force is lost and the suction cup is released from the container 33.

By adjusting the position of the valve 76 or more correctly that of the sensor arm 77 in relation to the container track 12, release of the suction cup 37 from the container 33 can be adjusted to coincide with a position where the container 33 is situated on or immediately above the container track 12. The reason why the container 33 is to be disengaged from the suction cup 37 before the edge of the container has reached the container track 12 is that the suction force is considerable and the container may become damaged, and a breakdown ensue, if the container is drawn off against the edge of the container track 12 with the suction cup 37 exerting the full suction force.

In order to facilitate vertical positioning of the container 33, the near part 102 of the container track 12 slopes, and care is taken that the valve device is adjusted so that the container 33 is released before reaching the sloping near edge 102 of the container track 12, but that the container is not disengaged before it has been brought to a position underneath the level defined by the container track 12 at the end of the sloping part 102. When the container 33 has been disengaged from the puller, it is positioned inside a holder 98 situated on the chain conveyor 13, by means of which it is intermittently moved onto position A. On the way to position A, the bottom of the container 33 is in contact with the container track somewhere along the sloping part 102, and the container 33 is steered in the vertical direction by the container track 12 until at the end of the sloping part 102 it has reached the correct level, with the bottom of the container resting on the container track 12.

We claim:

1. A packaging machine for the production of filled and sealed packages from package blanks of thermoplastic coated packaging material provided with fold lines to facilitate folding, said machine comprising an intermittently rotatable mandrel wheel, mandrels mounted outwardly thereabout, means for erecting the package blanks to form a rectangular shape, means for placing the erected blanks onto said mandrels, means for forming the bottoms of the packages, means for sealing the bottoms while on said mandrels to form open packages, conveyor means, adjustable holders provided thereon for the open packages, means for transferring the open packages from said mandrels to said conveyor means, means for prefolding the open ends of the open packages, means for filling the packages, means for closing the packages, means for sealing the packages, said mandrels comprising two sets of an equal number of mandrels, each set having a different cross-sectional area and being arranged alternately about said mandrel wheel, the mandrels of each set being spaced equidistantly from each other, means for intermittently rotating said mandrel wheel so that one set of mandrels moves consecutively between a series of stations arranged about said mandrel wheel for operations thereat and means for angularly displacing the mandrel wheel so that the other set of mandrels intermittently rotates between the series of stations for operations thereat.

2. A packaging machine as claimed in claim 1 wherein each of one set of said mandrels extends outwardly radially from the mandrel wheel and each of said alternating set of mandrels extends outwardly and parallel to but spaced from a radius of the mandrel wheel.

3. A packaging machine as claimed in claim 2 wherein the trailing face of each mandrel of each set of said mandrels takes the same position at each of the series of stations when each of said sets of mandrels is disposed to intermittently rotate between the stations for operations thereat.

4. A packaging machine as claimed in claim 1 wherein the means for sealing the bottoms of the packages while on the mandrels comprises a pressure means for sealing the bottom of the packages and means connecting said pressure means with said mandrel wheel to relieve stresses on said mandrel wheel caused by said pressure means.

5. A packaging machine as claimed in claim 4 wherein said connecting means includes a resilient means connecting said pressure means with said mandrel wheel so as to take up some of the pressure exerted by said pressure means.

6. A packaging machine as claimed in claim 1 and further comprising a drive shaft for said mandrel wheel, detent means, means resiliently mounted about said drive shaft for releasably engaging said detent means with said mandrel wheel whereby said mandrel wheel becomes disengaged from said drive shaft when said mandrel wheel is overloaded.

7. A packaging machine as claimed in claim 6 and further comprising means for continuously applying pressure to said resiliently mounted means to prevent said detent means from becoming permanently disengaged from said mandrel wheel.

8. A packaging machine as claimed in claim 1 wherein said mandrel wheel is provided with two sets of alternately arranged indentations to permit engagement of said detent means with one set of said indentations.

9. A packaging machine as claimed in claim 8 wherein one indentation of one set thereof is spaced equidistant from the adjacent indentations of the other set.

10. A packaging machine as claimed in claim 6 and further comprising means for restraining all of said detent means to prevent said detent means from engaging any of said indentation whereby said mandrel wheel may be disengaged from the said drive shaft.

11. A packaging machine as claimed in claim 10 wherein said restraining means comprises means for detecting the position of the resiliently mounted means for releasably engaging said detent means with said mandrel wheel and means cooperating with said detecting means for preventing engagement of said mandrel wheel with said drive shaft.

12. A packaging machine as claimed in claim 1 wherein said means for transferring the open packages from said mandrels to said conveyor means comprises reciprocal suction means for engaging the packages to withdraw them from said associated mandrel and deposit the package on said conveyor means, means for operating said suction means when a mandrel is in proper position with respect to said conveyor means.

13. A packaging machine as claimed in claim 12 and further comprising a suorce of vacuum and means for applying a vacuum to said reciprocal suction means when a package on a mandrel reaches the station and for releasing said vacuum when the package is adjacent said conveyor means.

14. A packaging machine as claimed in claim 13 wherein the vacuum is released when the package approaches said conveyor means.

15. A packaging machine as claimed in claim 1 wherein the package receiving end of the conveyor means includes a downwardly sloping ramp portion onto which the packages are transferred whereby said packages move upwardly along at least a portion of said sloping ramp portion before the bottoms of said packages move in continuous contact with the remaining portion of said conveyor means.

16. A packaging machine as claimed in claim 15 wherein the means for transferring the packages to said conveyor means releases the packages at a point below the level of the remaining portion of the conveyor means and above the downwardly sloping ramp portion.

References Cited UNITED STATES PATENTS 3,405,505 10/1968 Mistarz 53375 X THERON E. CONDON, Primary Examiner E. F. DESMOND, Assistant Examiner US. Cl. X.R.