GB2085832A

GB2085832A - A packaging machine

Info

Publication number: GB2085832A
Application number: GB8129986A
Authority: GB
Original assignee: Sapal SA
Current assignee: Sapal SA
Priority date: 1980-10-20
Filing date: 1981-10-05
Publication date: 1982-05-06
Also published as: IT8123765A0; IT1138566B; FR2492345A1; FR2492345B1; GB2085832B; CH637897A5; DE3133741C2; DE3133741A1

Abstract

The present invention relates to a packaging machine for preparing triangular portions of processed cheese. It comprises a chain 1 made up of links 2 each having two laterally disposed rollers 6. The driving and indexing of the chain is carried out by means of endless screw segments 9 which comprise helicoidal grooves 27 into which the rollers 6 penetrate. Rotation of the drive shaft 7 on which the segments 9 are mounted through half a revolution causes the chain to advance by one step. <IMAGE>

Description

SPECIFICATION A packaging machine The present invention relates to a packaging machine comprising a plurality of processing stations for at least one product, an endless conveyor chain for transferring the product from one processing station to the following station, and devices for driving and/or stopping this chain in position.

Machines of this kind are already known in which the positioning which calls for a high degree of precision at the processing stations, is effected by means of a pin which can be moved lengthways to its axis and which engages periodically in indexing bores provided for this purpose on the conveyor chain (French Patent published under No 2 070 431). This is particularly the case with machines for packaging processed cheese which are used for producing triangular portions. These machines usually comprise seven stations, which are as follows: 1. A station where the aluminium shells are formed by stamping suitably cut-up aluminium foil, 2. A dosing/pouring station for the processed cheese to fill the formed shells, 3. A station for placing the cover on the filled shells, 4. A station for folding the rounded edges of the triangular portions, 5.A station for folding the straight edges of these portions, 6. A station for compacting the cheese and sealing the cover by welding, for example, 7. Adeliverystationforthe packaged portions.

The precision with which the chain is indexed should be particularly high at the stations where the sheels are stamped, the station where the covers are put on, the folding stations and the station where compacting is carried out and the covers sealed. For this purpose, at each of these stations the machine comprises a positioning arrangement known as a centring device, such as that mentioned above.

These centring devices have the disadvantage that they require an independent control mechanism, with the result that the machine is more complicated and its cost is increased.

Furthermore, the time used to carry out the precise positioning of the conveyor chain is lost, which prevents the machine from operating at high production speeds and means that it has to recoup this lost time by excessively violent acceleration when the products are being transferred from one station to the next.

The present invention is intended to remedy the abovementioned drawbacks by producing a machine in which the indexing devices are combined with the drive devices, which enables approximately 80" to be gained per 360 cycle, that is to say, it makes it possible to operate at higher production speeds and to transfer the products more gently from one station to the next.

For this purpose the machine according to the invention is characterised in that the devices for driving and/or indexing comprise at least one pair of endless screw segments, each element of which is disposed laterally on one side of the chain along one of its straight sections, each segment having a generally cylindrical shape and being mounted on a drive shaft parallel to the said straight section of the chain, this shaft being coupled to a drive arrangement capable of engendering a cyclic rotation of the said shaft and of the corresponding segment, and in that each segment comprises at least one peripheral helicoidal groove designed to co-act with a set of rollers which are integral with the chain and are mounted laterally on its links so as to be able to engage in the said groove in the endless screw segment and to be entrained longitudinally for a distance equal to the length of one step of the chain.

The present invention will be better understood with reference to the description of an embodiment example and of the attached drawing, on which: Figure 1 is a schematic view from above of the packaging machine according to the invention, showing in particular the endless conveyor chain and the devices for driving and indexing this chain, Figure 2 is a schematic elevation side view of the machine shown in Figure 1, Figure 3 is an enlarged elevation view of the front end of the machine shown in figure 2, illustrating particularly the drive mechanism for the drives which drive the conveyor chain, and Figure 4 is an enlarged view of the drives for driving and indexing the conveyor chain.

With reference to the Figures, the machine depicted comprises bascially an endless chain 1, composed of a certain number of links 2 connected to each other by suitable couplings 3, and comprising transverse bars 4 on which a set of compartments 5 is mounted, intended for producing triangular portions of processed cheese.

Located at each coupling 3 between the links 2 of the chain 1 a roller 6 is mounted; this will be described in more detail with reference to Figure 4.

As Figures 2 and 3 show particularly clearly, the chain comprises two straight sections la and 1 b, connected by two sections 1 c and 1 d which curve in the arc of a circle. Along the straight sections 1 a and 1 b of the chain 1 the machine comprises two upper drive shaft 7 and two lower drive shafts 8 on which the endless screw segments 9 (shown in more detail in Figure 4) are mounted. Along the curved sections 1 c and id the chain has rails 10, of which there are four in the example shown, since there are four compartments 5 mounted on each transverse bar 4.

Figure 2 shows schematically the various processing stations through which the compartments of the chain 1 pass successively.

Station 11 is a station for shaping the aluminium shells in which pre-cut aluminium foil is introduced and stamped, assuming the shape of little boats accommodated inside the compartments 5.

Station 12 is the dosing/pouring station in which the molten cheese is poured in to fill the aluminium boat lining the bottom and sides of the compartments 5.

Station 13 is the station where the covers are put on.

Station 14 is the folding station; this is carried out in two stages: the folding of the rounded edge of the triangular portion, and then the folding of the straight edges.

Station 15 allows the cheese in the boat to be compacted, and the folded over edges of the cover to be welded.

Station 16 is a delivery station for the finished portions.

On this Figure it will be seen that each compartment has a movable base 17 attached to the upper ed of a rod 18, the lower end of which rests on a guide rail 19 comprising several sections. In particular, the trail 19 comprises a ramp 20 which is intended to cause the movable base 17' of the compartment 5' to lift up (see Figure 2).

Figure 3 shows schematically the drive mechanism of the upper drive shafts 7 and the lower drive shafts 8.

This mechaism comprises two drive wheels or pinions 21 which are linked together (in a manner which is not shown) so that they are driven in a synchronised fashion, and connected via bells or chains 22 to an upper drive shaft 7 and a lower drive shaft 8 respectively. In the example shown, the mechanism is designed to make the drive shafts 7 and 8 turn through half a revolution on each working cycle, and a tensioner 21' is mounted on each belt of the machine.

As is shown in more detail in this Figure, the compartments 5 comprise a support 23 at their base which allows them to be mounted on the transverse bar 4 of the chain 1. This support is made integral with the transverse bar by means of some fixing device such as a screw, a bolt or a pin 24 which engages in the periheral groove 25 provided in the support 23. The support 23 comprises a bore through which the rod 18 passes, bearing on its upper end the movable base 17. The lower end of the rod 18 is equipped with a bearing 26 the task of which is to rest on the guide rail 19 and espcially on the ramp 20.

The driving and indexing of the chain 1 is effected by means of endless screw segments 9, each of which has two peripheral helicoidal grooves 27. These grooves have a straight trapezoidai section which corresponds substantially to the truncated cone shape of the rollers 6 engaged in one of the grooves 27.

To prevent the movable bases 17 from coming out of the compartments when the chain is inverted (lower section 1 b), longitudinal guides 28 are disposed under each line of compartments to act as supports for the bases 17 and for the rod 18.

With reference to Figure 4, the endless screw segments 9, viewed from above, are slightly longer than one step of the chain. In fact, this length is substantially equal to or slightly greater than the length of one step of the chain plus a length which is equal to one diameter of a roller 6. This characteristic, combined with appropriate positioning of the segments 9 along the straight sections of the chain, makes it possible to obtain an embodiment in which two rollers 6 and 6' (see Figure 4) are simultaneously accommodated in one and the same helicoidal groove 27 when the chain stops.

Each segment 9 has two grooves 27 and 27' provided symmetrically along its periphery in such a way that half a revolution by the drive shaft 7 causes the chain to advance by one step.

One of the functions of the endless screw segments consists in making the chain advance step by step. A second function consists in indexing this chain, that is to say, in correcting any errors in positioning which may arise when the chain is being displaced. For this purpose the entrance to each groove 27 is slightly widened so as to allow the rollers to enter without a joit, even if they are not in their theoretical position at the moment when they enter the corresponding groove 27.

Because of this second function it is essential to place a segment 9 at each processing station where a high degree of precision is required in the positioning of the compartments.

The number of grooves provided on each segment is limited only by practical constructive considerations.

The number of grooves, as well as their step, determines the number of revolutions or the numercial fraction of a revolution of a segment engendering the advance of the chain by one step. It is therefore conceivable to make one step of the chain correspond to one whole revolution or a whole multiple of revolutions of the drive shaft 7, or to a whole sub-multiple of a revolution of this shaft.

Claims

1. A packaging machine comprising a plurality of processing stations for at least one product, an endless conveyor chain for transferring the product from one processing station to the following station, and devices for driving and/or stopping this chain in position, characterised in that the devices for driving and/or stopping the chain in position comprise at least one pair of segments of an endless screw each element of which is disposed laterally on one side of the chain along one of its straight sections, each segment having a generally cylindrical shape and being mounted on a drive shaft parallel to the said straight section of the chain, the said shaft being coupled to a drive arrangement capable of engendering a cyclic rotation of the said shaft and of the corresponding segment, and in that each segment comprises at least one peripheral helicoidal groove designed to co-act with a set of rollers which are integral with the chain and are mounted laterally on its links in such a way as to enable them to engage in the said groove in the endless screw segment and to be entrained longitudinally over a distance equal to the length of one step of the chain.

2. A machine according to Claim 1, characterised in that the length of the endless screw segment is at least equal to one step of the machine, and in that the shape of the helicoidal groove is designed so that the rotation of the segment by a whole multiple or sub-multiple of a revolution corresponds to the advance of the chain by one step.

3. A machine according to Claim 1, characterised in that the endless screw comprises two symmetrically disposed peripheral helicoidal grooves, and in that the rotation of the segment through half a revolution corresponds to the advance of the chain by one step.

4. A machine according to Claim 1, characterised in that the helicoidal groove has a straight trapezoidal section which is open towards the outside and in that the rollers have a truncated cone shape such that they are able to penetrate into the groove the rest against its lateral walls.

5. A machine according to Claim 4, characterised in that the entrance to the helicoidal groove widens out, this widening out being such that is allows a positioning error in the rollers to be accommodated.

6. A machine according to Claim 2, characterised in that the length of the endless screw segment is equal to the length of one step of the chain plus a length which is equal to at least one roller diameter, the endless screw segments being disposed along the chain in such a way that every time the chain stops, two rollers will be engaged in one and the same helicoidal groove in the screw segments.

7. A packaging machine constructed, arranged and adapted for use substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.