GB2160843A - Wrapping parcels - Google Patents

Abstract

A method of wrapping a parcel 23 is characterised in that the parcel is placed on a conveyor belt (7), a sheet of wrapping material (141) is placed around the parcel so that a portion covers at least partially the underside, the front face, and the upper face, the rear edge of the sheet extending beyond the rear face of the parcel is pushed under the conveyor belt by a bar 16 through a first slot (12) after which there is relative movement of a slot (19) in the conveyor belt and the parcel (23) without the parcel sliding on the conveyor belt, in order to position the rear edge of the sheet below the front edge portion of the sheet which is situated below the parcel. The edges of the sheet are then joined, for example, by glueing before the parcel and wrapping are passed to a heat shrinking enclosure. A machine for carrying out the method is also claimed. <IMAGE>

Description

SPECIFICATION Method of and installation for packing up a parcel by means of a sheet of wrapping material and the packed parcels obtained The invention relates to a method of and an installation for the packing of a parcel by means of a sheet of wrapping material, and also the parcels obtained.

The invention is in particular applied to the packing of parcels consisting of a group of objects such as bottles, cans or sub-groups of already packaged objects, using a sheet of thermo-shrinkable plastics materials.

At present, when it is desired to pack up a group of objects 1 (see Fig. 1) by means of a sheet of thermo-shrinkable plastics material 2, this sheet is placed around adjacently disposed objects 1 so that the two ends of the sheet are assembled at 3 by gluing or thermo-welding, the sheet then undergoing thermo-shrinking operations, the object of which is to cause the thermo-shrinkable sheet strongly to grip the group of objects which are thus rendered rigid against one another.

This known method of assembly has various drawbacks. In particular, it results in the formation of parcels which are not very attractive to look at by reason of the two assembled together edges of the sheet which form a peak on the top of the parcel and also it does involve a relatively high consumption of plastics film by reason of the assembled lengths of film used to make up the peak.

However, the most significant disadvantage lies in the fact that it produces parcels which are not assembled together in a very solid fashion by reason of the fact that the two adjacently disposed edges of the film at 3 form a crest which is orientated at a right-angle to the upper face of the parcel, that is to say perpendicularly to the zones 2 adjacent the two assembled edges 3. Well, when the film is shrunk under heat or possibly when the parcel is handled after heat shrinking, the forces engendered are exerted in zones 2,, that is to say at a right-angle to to the assembled surfaces of the ends 3, such that these forces have a tendency progressively to separate the assembled surfaces in view of the fact that they are exerted on the bottom junction line connecting these surfaces.

the special object of the present invention is to remedy these drawbacks and in particular to make it possible to produce a parcel (see Figure 2), in which the grouped together objects 1 are enclosed by a sheet 4 such as a sheet of thermoplastics shrinkable material, the ends 4, and 42 of this sheet being situated below the underside of the group of objects and being superposed and assembled one to the other by gluing or thermowelding in such a way as to form a junction surface parallel with the bottom surface of the grouped together objects.

Thus, this assembly zone, situated under the group of objects, is concealed, while this method of assembly makes it possible to reduce the length of plastics film necessary and produces a solid junction by reason of the fact that the traction forces are exerted parallel with the surfaces of the assembled ends 41 and 42 For this purpose, the invention relates to a method of packing up a parcel using a sheet of wrapping material, a method which is characterised in that a parcel which is to be wrapped is placed on a conveyor belt, a sheet of wrapping material is placed around this parcel so as to cover at least partially its underside, one of its side faces referred to as the front face and its upper face, the rear edge of the sheet extending beyond the rear side face of the parcel, the rear edge of the sheet is pushed under the conveyor belt through a first slot with which it is provided and the slot in the conveyor belt and the parcel are displaced relative to each other without the parcel sliding on the conveyor belt, in order to position the rear edge of the sheet under the front edge of the sheet which is itself situated under the parcel.

According to another characteristic feature of the invention, the wrapping sheet comes from a roll of film intended for wrapping parcels brought in succession along the conveyor belt, a method which is characterised in that an operating cycle is established whereby the sheet is positioned substantially vertical in relation to the conveyor belt so as to form a curtain of sheet which traverses a second slot in the conveyor belt, the free end of the sheet being situated under the conveyor belt, after which the first of the parcels to be wrapped is moved over the conveyor belt and towards the curtain until such time as this first parcel is situated beyond the said second slot, the sheet then covering at least partially the underside, the front face and the upper face, the sheet being pushed in and folded between the first parcel and a second parcel until such time as the folded part of the sheet penetrates into the second slot and the part of the sheet which is folded back under the conveyor belt is then cut off transversely in such a way that the new end of the sheet from the roll forms a new curtain of sheet for the second parcel, the first parcel wrapped in the cut off portion of sheet being carried towards the first slot in the conveyor belt for wrapping.

According to another characteristic feature of the invention, the first and second slots in the conveyor belt merge into each other and the sheet, while being folded over, is pushed between a first and a second parcel until the folded part of the sheet penetrates the single slot and the single slot in the conveyor belt and the parcel are displaced relative to each other to positon the two edtes of the cut off fold of the sheet under the first parcel after which the slot is restored to the starting position.

The invention likewise relates to a machine for carrying out the method, this machine being characterised in that it comprises an endless belt stretched over rollers so that its upper run forms a horizontal conveyor belt for the parcel to be wrapped, a trolley under the upper run of the belt, the said trolley being capable of performing a reciprocating movement parallel with the conveyor belt and comprising rollers over which the upper run of the belt passes to form a first transverse solt over the conveyor belt, means situated above the upper un of the belt, said means being adapted for movement towards the upper run of the belt to penetrate into the first slot and entrain the sheet into this slot.

According to another characteristic feature of the invention, the trolley comprises at least three freely-rotatable parallel rollers, two of these being situated at the height of the conveyor belt and defining between them the first slot, the third roller being situated under the first two, the upper run of the belt passing over these rollers to form a loop underneath the conveyor belt, this loop emerging through the slot on this conveyor belt.

According to another characteristic feature of the invention, the means of pushing the sheet into the second slot while folding it comprises a bar adapted for alternating movement between an upper position and a lower position situated respectively above and below the conveyor belt and passing through the second slot, the bar when in its low position applying the fold of the sheet onto a means of cutting the sheet.

The invention is illustrated by way of non-limitative example in the appended drawings, in which: Figure 1 diagrammatically shows a parcel wrapped according to the known method; Figure 2 represents a parcel wrapped by the method according to the invention; Figure 3 is a side view of an embodiment of the machine according to the invention, for intermittent operation; Figure 4 is a plan view of Figure 3; Figures 5a to 5g illustrate the working cycle performed by means of the machine shown in Figures 3 and 4; Figure 6 is a side view of a modified embodiment of the invention, for continuous operation, and Figures 6a to 6e illustrate the working cycle of the machine shown in Figure 6.

The machine shown in Figures 3 and 4 is composed of two juxtaposed machine frames 5 and 6 mounted on wheels. The frame 5 comprises two endless belts 7 and 8 disposed one behind the other in the direction of travel of the parcel to be wrapped (arrow F) while the frame 6 comprises an endless belt 9 disposed after the belt 8 in such a way that the upper run of the belts 7,8 and 9 constitutes a conveyor belt 10 for the objects which are to be wrapped.

These belts 7, 8 and 9 are stretched taut and displaced by rollers 11. These rollers are disposed in such a way that a slot 11 is formed between the two belts 7 and 8, this slot being situated above a shoulder 13 provided on the one hand with suction means for maintaining the end of the wrapping sheet emanating from the roll 14, and on the other means of cutting this sheet.

Above the belt 7, the frame 5 comprises a support 15 provided with means 151 capable of producing vertical displacement of a horizontal bar 16.

Thus, this bar 16 is adapted for movement between a high position (see Figure 3) and a low po- sition (see Figure 5c), for which, after having traversed the slot 12, it bears against the shoulder 13.

Likewise provided on the support 15 is a horizontal plate 17 which can be moved between a high position and a low position, this plate 17 when in the low position applying itself against the upper face of the parcel to be wrapped and which is partially covered by the sheet from the roll 14.

The endless belt 8 constitutes the actual wrapping belt and under the conveyor belt 10 it is provided with four rollers 181,182" 183 and 184 over which the upper run of the endless belt 8 passes in order to form a loop 8,.

Thus, according tothis embodiment, the rollers 18 and 183 are disposed at the height of the conveyor belt 10 and confine between them a transverse slot 19, while the other two rollers 183 and 184 are disposed at a lower level to form this loop 8i.

Above the slot 19, the frame 5 comprises a support 20 over which there is a vertically sliding shutter 21 adapted to penetrate into the loop 8 by passing through the slot 19.

These rollers 18i, 183, 18s, 184 are disposed on the frame 5 through a carriage or trolley on which they are free to rotate, the carriage being adapted to perform a reciprocating movement parallel with the conveyor belt 10, that is to say in the direction of the arrow F and in the opposite direction thereto. It will be appreciated that by the displacement of this carriage in the direction of or in opposition to the direction of the arrow F, the loop 8 and the slot 19 are displaced without the movement of the endless belt 8 itself being altered.

After the wrapping of a parcel by the elements 7, 8, 13, 16, 17 and 21, the parcel arrives on the endless belt 9 and enters a heated enclosure 22 in which the plastic film enclosing the parcel is subjected to heat shrinking.

In the foregoing description, with a view to simplification, no mention has been made of the means for gluing or thermally welding the two edges 41 and 43 of the sheet 4 surrounding the parcel (see Figure 2). The said means, which are known per se, may be provided either at the heigh of the shoulder 13 or between the slots 12 and 19 if the assembly process involves gluing. On the other hand, if assembly is carried out by welding under heat, the said means will be provided between the slot 19 and the enclosure 22 or even inside the said enclosure 22.

The way the machine operates is illustrated in Figures 5a to 5g.

At the commencement of the working cycle, it is considered that a parcel 23 is offered up on the endless conveyor 7, moving in the direction of the arrow F, while the sheet of plastics material 141 emanating from the roll 14 forms a vertical curtain passing through the slot 12, its bottom end being maintained on the shoulder 13 by the suction means comprised therein.

As it continues to advance in the direction of the arrow F, the parcel 23 pushes into the curtain consisting of the sheet 14" unrolling it from the roll 12 and separating its free end from the shoulder 13.

At this stage, the sheet 14, is disposed partly under the underside 23 of the parcel, it also covers the front face 232 and prepares to cover totally the upper face 232. When the parcel 23 has passed beyond the slot 12, the two rollers 11, and 112 which define the slot 12 move aside from each other while maintaining the belts 7 and 8 under tension, the belt 8 being immobilised.The plate 17 is then lowered until it applies the sheet 14 to the upper face 232 of the parcel while the bar 16 is lowered through the widened slot 12 until it applies the sheet of plastics material against the shoulder 13, which has the effect of cutting off the sheet and of maintaining, by the action of the suction means, the part 142 of the sheet which is connected to the roll so that this part constitutes a fresh curtain for the subsequent parcel 24. The endless belt 8 is then set in motion again and the parcel 23 which is partially covered by the sheet 141 moves towards the slot 19 (Figure 5d).

When the parcel 23 has passed beyond the slot 19, the shutter 21 descends through this slot into the interior of the loop 811 the effect of this being to push into the interior of this loop and through the slot the rear part of the sheet 141 which extends beyond the rear edge 234 of the parcel.

The shutter 21 then rises to the high position then (see Figure 5f) the carriage which support the rollers 18" 182, 182 and 184 so that they can rotate freely is displaced in the direction of the arrow F, the effect of this being to displace the slot 19 without giving rise to relative displacement of the endless belt 9 in relation to the parcel 23, which are both preferably immobile. During the course of this operation, the part of the sheet 14 introduced into the loop 81 becomes positioned against the underside 231 of the parcel 23 so that the rear end of the sheet is superimposed on the front end, itself applied against the underside of the parcel.The parcel is then completely enclosed by the wrapping sheet and the endless belt 9 is set in motion again, while the carriage comprising the rollers 18" 182, 182 and 184 returns to the starting position (see Figure 5g). The parcel 23 is then displaced towards the heat shrinking enclosure 22 after the two superimposed ends of the sheet have been suitably glued or heat-shrunk.

In the embodiment shown in Figures 3, 4 and 5a to 5g, the machine comprises two slots 12, 19 through which pre- packaging and then wrapping of the parcel by the sheet are respectively performed. In the example shown in Figures 6 and 6a to 6e, a modified embodiment of this machine is shown in which these two slots 12, 19 are merged into a slingle slot 23 formed between two endless belts 25 and 26 of which the top run forms a conveyor belt 27 for the parcels to be wrapped, for continuous operation.

The construction of this machine will be described at the same time as its operation.

According to Figure 6 which shows the machine in a position taken as the point of departure of the working cycle, the parcel 28 pushes into the curtain formed by the sheet or film 291 emanating from the roll 29, the said sheet or film having its bottom end passing through the slot 24. On either side of the conveyor belt are two endless chains 30 maintained under tension by rollers 31, the said chains being connected by a transverse bar 32 designed to push the sheet 291 through the slot 24 and by a cutting bar 33 adapted to cut off the sheet. The cutting bar 33 is disposed after the pushing-in bar 32 in the direction of travel (arrow F1) of the chains 30 and the cutting bar 33 is to co-operate with a counter cutting bar 34 situated under the slot 24.

According to Figure 6a, the parcel 28 continues its movement of pushing into the curtain of film 291 and this advacing movement is produced continuously until the end of the working cycle.

According to Figure 6b, the parcel 28 has moved beyond the slot 24 and is enclosed over its upper face, its front face and partially its underside, by film 291. At this stage of operations, the bar 32 entrained by the chains 30 becomes applied to the film 29" folding it over and pushing it through the slot 24.

According to Figure 6c, the sheet 29 entrained by the bar 32 continues its descent in the foldedover state and the cutting bar 33 co-operates with the countering cutting bar 34 in order to cut through the film 29,, the slot 24 then comprising the cut off rear end of the film 29, and the front edge of the film 292 which is joined to the roll 29.

In the subsequent stage (see Figure 6d), the rollers 25, and 26, of the endless belts 25 and 26 which define the slot 24 are displaced in the direction of travel of the parcel 28 so that this slot tightens up the parcel, until such time as the roller 25 applies the rear edge of the film 29, below the front edge which is itself positioned under the parcel 28. During the course of this movement, the film 292 which is still attached to the roll 29 is likewise entrained but its bottom end remains hanging below the slot 24, having regard to its greater length.

Finally (see Figure 6e), the rollers 25 and 26, move in the opposite direction to the parcel 28 in order to return to the starting position (Figure 6) to carry out the wrapping of a fresh parcel 35 using the sheet 292 which forms a curtain through the slot 24.

During the return movement of the rollers 25, and 26, it will be noted that the rear edge of the film 29, remains applied against the underside of the parcel 28 due to its shorter length and hence to its low weight while on the other hand the front edge of the sheet 292 becomes disengaged from the underside of the parcel 28 by virtue of the fact that this front edge is not totally withdrawn from the slot 24 and also by virtue of its greater length and hence its greater weight.

Claims (11)

1. A method of wrapping a parcel using a wrapping sheet, the said method being characterised in that a parcel (23) which is to be wrapped is placed on a conveyorbelt (10), a sheet of wrapping material (14,) is placed around the parcel so that it covers at least partially its underside (23,), one of its lateral faces (232) referred to as the front face, and its upper face (233), the rear edge of the sheet extending beyond the rear lateral face (234) of the parcel, the rear edge of the sheet being pushed under the conveyor belt (10) through a first slot (19) with which it is provided after which there is relative movement of the slot (19) in the conveyor belt and the parcel (23) without the parcel sliding on the conveyor belt, in order to position The rear edge of the sheet (14,) below the front edge of this sheet which is itself situated below the parcel (23).

2. A method according to Claim 1, characterised in that the wrapping sheep (14.) emanates from a roll of film I i adapted for the wrapping of parcels brought in succession on the conveyor belt (10), the said method being characterised in that a working cycle is established whereby the sheet (14,) is positioned substantially vertically in relation to the conveyor belt (10) so as to form a curtain of sheet which traverses a second slot (12) in the conveyor belt (10), the free end of the sheet being situated under the conveyor beit, the first of the parcels (23) to be wrapped being moved on the conveyor belt and towards the curtain until such time as this first parcel is situated beyond this second slot (12), the sheet then at least partially covering the underside (23), the front face (232) and the upper face (233), the sheet is folded over and pushed between the first parcel (23) and a second parcel (24) until such time as the folded-over part of the sheet penetrates the second slot (12) and the part of the sheet which is folded over under the conveyor belt is cut off transversely so that the new end (142) of the sheet from the roll (14) forms a fresh curtain of wrapping sheet or film for the second parcel (24), the first parcel (23) wrapped in the cut-off part of the sheet (14) being conveyed towards the first slot (19) in the coniC/Or belt (10) to be wrapped.

3. A method according to Claims i and 2, according to which the first and second slots in the conveyor belt merge and according to which the sheet (29,) is pushed in and folded over between a first parcel (28) and a second parcel (35) until such time as the folded-over part of the sheet penetrates the single slot (24) and there is a relative displacement between the single slot (24i in the conveyor belt and the parcel (28) in order eo position the two edges of the cut off fold (28,, 292) of the sheet under the first parcel (28), after which the slot (24) is returned to its starting position.

4. A machine for carrying out the method according to Claims 1 or 3, characterised in that it comprises an endless belt (9) maintained under tension over rollers (11), its upper run forming a horizontal conveyor belt (10) for the parcel (23) which is to be wrapped, a carriage or trolley (18,, 182, 182 and 184) under the uppar run of the belt, the said carriage being adapted to perform a reciprocating movement parallel with the conveyor belt and comprising rollers over which the upper run of the belt passes to form a first transverse slot (19) on the conveyor belt, means (21j situated above the upper run of the belt, the said means being adapted for movement towards the upper run of the belt to penetrate the first slot (19) and entrain the sheet into this slot.

5. A machine according to Claim 4, characterised in that the carriage comprises at least three freely rotatable parallel rollers (18,, 182, 182), two of them (18,, 18,) being situated at the height of the conveyor belt and defining between them the first slot (19), the third roller (183) being situated under the first two, the upper run of the belt passing over these rollers (18?,182,133) to form a loop (8,) under the conveyor belt, this loop emerging through the slot (19) on this conveyor belt.

6. A machine for carrying out the method according to Claim 2, characterised in that the means of folding over the sheet and pushing it into the second slot (12) comprises a bar (16) adapted for movement alternately between an upper position and a lower position situated respectively above and below the conveyor belt (10), and passing through the second slot (12), the bar (16) when its in its lower position applying the fold in the sheet 11A) against a sheet cutting means (13).

7. A machine according to Claim 6, characterised in that the sheet cutting means are provided on a shoulder (13) disposed below the second slot (12), the said shoulder likewise comprising suction means for maintaining the cut off sheet positioned against this shoulder.

8. A machine according to Claim 7, characterised in that the height of the shoulder (13) is adjustable.

9. A machine according to any one of Claims 4 to 7, characterised in that the endless belt of which the upper run forms the conveyor belt is constructed by means of two endless belts (7-8; 25-26 maintained under tension on rollers and defining between them a slot (12, 24).

10. A machine according to Claim 9, characterised in that the rollers (11,, 112) of the two belts (7, 8) defining between them the slot (12) are regulable in the amount by which they are spaced apart.

11. A machine according to Claims 4 and 9, in which the two slots merge, characterised in that the means adapted for movement towards the upper run of the belt to penetrate the slot consist of bar (32) movable in a closed circuit supported laterally to the conveyor belt by chains for entraininc the sheet (29,) into the slot (24L) formed between the rollers (25, and 26,), the said chains (30) likewise supporting a cutting bar (33) situated behind the bar (32) for pushing in the sheet in relation to its direction of -travel, this bar (33) co-operating with a counter cutting bar (34) situated below the slot (24) for cutting off the sheet.