EP1486419A1

EP1486419A1 - Feeding device for a packaging machine

Info

Publication number: EP1486419A1
Application number: EP03425386A
Authority: EP
Inventors: Christian Zagnoni; Gilberto Poli
Original assignee: TMC SpA
Current assignee: TMC SpA
Priority date: 2003-06-13
Filing date: 2003-06-13
Publication date: 2004-12-15

Abstract

A feed device for machines for producing packs using layers (2) of products positioned one on top of the other, starting with a feed line for single layers comprises a first fixed surface (4) and a second fixed surface (5), set at a distance from one another, coplanar and aligned, on which the single layers of products slide, a third fixed surface (7) below and parallel with the second surface, and a fourth fixed surface (8) connecting the first and the third surfaces, there being between the first and second surfaces transfer means (103,104) which collect a layer of products exiting the first fixed surface and carry it to the second fixed surface, the means alternating with empty spaces designed to allow the next layer of products to drop from the first fixed surface to the fourth fixed surface.

Description

The present invention relates to machines designed to produce packs of rolls of products, for example, packs of rolls of toilet paper, consisting of at least two layers of products.
Such machines have a line which feeds the products on various parallel rows, a station in which layers of the products are prepared, consisting of rows of products positioned side by side, a station in which at least two of the layers are stacked one on top of the other to form a pack, and a station in which the packs prepared in this way are wrapped in a sheet of synthetic material.
The machine must preferably also be able to produce a pack consisting of a single layer.
In known machines, the wrapping station comprises an elevator plate designed to receive at least one layer forming the pack, and preferably at least two layers already positioned one on top of the other, and to place said pack on the worktable of the unit designed to wrap the sheet around it.
A machine of the above-mentioned type is described in patent application number BO97A000745 by the same applicant.
Each layer consists of at least two products which normally have an almost cylindrical shape and which must be on top of two identical products with the axis horizontal. Therefore, the two layers, placed one on top of another, are characterised by a very unstable equilibrium basically because the individual products are of a soft consistency and so are deformed and slightly flattened at their contact surface.
Therefore, absolute synchronism is required when transferring the layers from the individual surfaces which receive them to the elevator plate downstream, and absolute precision for their positioning.
More precisely, in known machines there are intermediate surfaces, designed to receive each single layer, distanced from one another vertically and fed in succession by a single belt by means of an oscillating surface which is sequentially positioned in front of each surface.
The layers move forwards on said surfaces, pushed by pushers which keep them precisely one on top of the other, and are unloaded onto the elevator, forming the desired multi-layer pack of products on the elevator.
Pack transfer to the elevator surface necessitates the use of a thrust chain for each layer, therefore, at least two thrust chains, whose movements must for obvious reasons be perfectly synchronised.
This prevents the inertial stresses caused by the high speed of the machine from moving the upper layer relative to the lower layer.
The need to use the oscillating surface not only leads to mechanical complications and the necessity for the complicated adjustment and set-up operations which characterise known machines, but is also the source of vibrations and inertia phenomena which may lead to incorrect positioning of the product and, therefore, faulty pack formation on the elevator plate.
The aim of the present invention is to overcome the above-mentioned disadvantages by providing a simple, reliable and economical solution which does not include an oscillating surface.
Accordingly the machine disclosed comprises, in the direction of product feed, a first fixed horizontal surface, a second fixed horizontal surface coplanar with the first and set at a distance from the first which will be defined below, a third fixed horizontal surface below the second fixed horizontal surface and set at a distance from it equal to at least the maximum thickness of the layer of products, and a fourth fixed angled surface which connects the first fixed surface to the third fixed surface.
The distance which separates the first and second fixed surfaces must be sufficient to allow each layer to slide from the first to the fourth fixed surfaces without interfering with the second.
Said distance will certainly be sufficient if it is equal to the maximum size of the layer of products measured in the latter's direction of feed.
The above-mentioned surfaces, although defined as fixed surfaces, and remaining fixed once correctly positioned, may preferably be adjustable to adjust their distance to the thickness of the layers to be stacked.
The present invention also comprises first thrust means which act upon the layers supported by the first and second surfaces, second thrust means which act upon the layers supported by the third surface, and third thrust means which act upon the layers supported by the angled or fourth surface.
The first, second and third thrust means consist of pairs of chains bearing horizontal cross-members at right angles to the chains.
The step between the cross-members of the first thrust means is half the step between the cross-members of the second and third thrust means.
Moreover, the cross-members of the first and third thrust means are perfectly synchronised, whilst the cross-members of the second thrust means are out of phase by half a step relative to the cross-members of the second thrust means.
Between the first and second fixed surfaces there are two more side chains which between them support a slat conveyor with at least one slat section and at least one empty section whose size is at least equal to the maximum size of the layers in the direction of feed.
The slat conveyor will preferably have two equal slat sections, separated by empty spaces of the same size.
Movement of the slat conveyor is synchronised with the thrust means, the rear edge of the slat section synchronised with the cross-members of the thrust means in the direction of feed.
Below the first fixed surface there is a mobile surface driven into position as a continuation of the first fixed surface, its size, in the direction of feed, being at least equal to the distance between the first and the second surfaces minus the size of the slat section in the direction of feed.
Thanks to the layout described above, the first layer intended to form the pack is fed forwards on the first fixed surface, reaches the empty area of the slat conveyor and slides onto the fourth angled surface and then onto the third fixed surface.
The next layer intended to form the pack reaches the edge of the first fixed surface together with a slat section, goes onto the latter and is accompanied as far as the second fixed surface.
The layers positioned on the second and third fixed surfaces are then simultaneously pushed onto the elevator device downstream.
The advantages and construction and functional features of the invention are evident in the detailed description which follows, with reference to the accompanying drawings, which illustrate a preferred embodiment without limiting the scope of application, and in which:

Figure 1 is a schematic side view of the invention;
Figure 2 illustrates the same invention in a different operating position;
Figure 3 is a plan view of the invention.

The figures illustrate the surface 1 on which the single layers 2 arrive, each layer consisting of six rolls 21.
Downstream of the surface 1 there is a short section of flat conveyor 3 followed by a first horizontal fixed surface 4.
Downstream of the surface 4 and coplanar with it, at a suitable distance, there is the second horizontal fixed surface 5.
Attached to the surfaces 4 and 5 there are first thrust means 6 consisting of a pair of chains 61 stretched between pulleys from 63 to 68, and having equidistant horizontal cross-members 62.
Below the surface 5 there is a third horizontal fixed surface 7, whilst between the surface 7 and the surface 4 there is a fourth angled fixed surface 8.
Second thrust means 9, similar to the means 6 and comprising chains 91 and cross-members 92 are attached to the surface 8 and third thrust means 10, similar to the previous ones and comprising chains 101 and cross-members 102 are attached to the surface 7.
The step of the cross-members 92 and 102 of the thrust means 9 and 10 is double the step of the cross-members 62 of the thrust means 6.
The cross-members of the thrust means 6 and 9 are perfectly synchronised with one another, in the sense that the cross-members of the means 9 are positioned at every other cross-member of the means 6, whilst the cross-members of the means 10 are out of phase by half a step relative to the cross-members of the means 9.
Between the surface 4 and the surface 5, at their sides, there are two parallel chains 11, stretched between the idlers 111, their upper sections perfectly coplanar with the surfaces 4 and 5.
Two identical slat sections 104 and 103 are supported between the chains 11. Said sections are preferably separated from one another by a distance equal to the distance separating the surfaces 4 and 5, having a size in the direction of layer feed at least equal to the size of the layers.
The chains 111 are driven at the same speed, and are perfectly synchronised with the thrust means 6, 9 and 10.
Below the first fixed surface 4 there is a mobile surface 400 driven by a piston cylinder unit 401 into position as a continuation of the first fixed surface 4, having a size, in the direction of feed, at least equal to the distance between the first 4 and the second 5 fixed surfaces minus the size of the slat section 103/104 in the direction of feed.
The invention operates as follows.
When only a single layer is to be fed to the elevator plate, the chain 11 is stopped in the position in which one of the slat sections 103/104 is horizontal and adjacent to the fixed surface 5.
The surface 400 is moved forwards to guarantee the continuity of the supporting and sliding surface for the layer 2 from the surface 4 to the surface 5, from which the layer is thrust onto the elevator plate, not illustrated, by the cross-member 62.
In contrast, when two layers positioned one on top of the other are to be fed onto the elevator plate, the surface 400 is retracted under the surface 4 and the chains 11 are driven at the same speed, with the front edges of the slat sections synchronised with the cross-members 62 and 92.
A first layer 2 arrives at the end of the surface 4 with the slat section 104 positioned as illustrated in Figure 2, and continues moving onto the angled surface 8 as far as the surface 7, accompanied by the second thrust means 9 which receive it on the surface 8 and push it forwards to the surface 7.
The next, second layer intended to form the pack reaches the edge of the surface 4 together with the slat section 104, is received by the latter and accompanied to the surface 5.
When the second layer is on the surface 5, the first thrust means continue pushing it until it is on the elevator device located downstream.
At the same time the first layer lying on the surface 7 below is collected by the third thrust means 10 and pushed onto the elevator, on which it is positioned precisely below the second layer.
As already indicated, the step between the cross-members 102 of the thrust means 10 is double the step between the cross-members 62 of the first thrust means, allowing the first layer to remain stationary on the surface 7 until the second layer arrives.
The rear edge of each slat section 103/104, in the direction of feed, is synchronised with one out of every two cross-members 62.
The cycle is repeated in an identical manner.
The first, second and third pusher means, the slat conveyor 11, and the piston cylinder unit 401 are controlled in a synchronised fashion by a single programmable processor.
As indicated, downstream of the surfaces 5 and 7 there are usual elevator means, not illustrated, such as a plate which moves vertically, onto which the two layers on the surface 5 and 7 drop without sliding one on top of the other.
More details about some of the above-mentioned means are omitted since they are easily made by experts in the field according to their normal know-how.
Moreover, all of the thrust means and the slat conveyor may be driven, in such a way that they are synchronised with one another, by a single motor.

Claims

A feed device for machines for producing packs with layers of products positioned one on top of another, starting with a feed line for single layers, characterised in that it comprises a first fixed surface and a second fixed surface, being set at a distance from one another, coplanar and aligned, on which the single layers of products slide, a third fixed surface below and parallel with the second surface, and a fourth fixed surface connecting the first and the third surfaces, there being between the first and second surfaces transfer means which collect a layer of products exiting the first fixed surface and carry it to the second fixed surface, the means alternating with empty spaces designed to allow the next layer of products to drop from the first fixed surface to the fourth fixed surface.
The device according to claim 1, characterised in that first pusher means are attached to the first and second fixed surfaces, being designed to accompany the product from the start of the first fixed surface to the outfeed of the second fixed surface, whilst attached to the third and fourth surfaces there are second and third pusher means driven in such a way that they are synchronised with the first pusher means and designed to accompany the single layers from the infeed to the outfeed of the respective surfaces.
The device according to claim 1, characterised in that the transfer means consist of a slat conveyor with the upper branch coplanar with the first and second surfaces, in which slat sections whose size in the direction of feed is at least equal to the maximum size of each single layer in the same direction are alternated with sections on which there are no slats, of at least the same size.
The device according to claim 2, characterised in that the first pusher means consist of a pair of parallel chains with a branch parallel with the surface attached to them, and carrying between them a set of equidistant cross-members, the distance between them being at least equal to the distance between two successive layers arriving on the first fixed surface.
The device according to claim 2, characterised in that the second pusher means consist of a single pair of parallel chains with a branch parallel with the fourth fixed surface attached to them, and carrying between them a set of equidistant cross-members, the distance between them being double the distance between the cross-members of the first pusher means.
The device according to claim 2, characterised in that the third pusher means consist of a single pair of parallel chains with a branch parallel with the third fixed surface attached to them, and carrying between them a set of equidistant cross-members, the distance between them being equal to the distance between the cross-members of the second thrust means, whilst their position is out of phase by half a step relative to the cross-members of the second thrust means.
The device according to claim 1, characterised in that below the first fixed surface there is a mobile surface designed to move into position as a continuation of the first surface and having a length, in the direction of layer feed, at least equal to the distance between the first surface and the second fixed surface minus the size of the transfer means in the direction of feed.
The device according to claim 1, characterised in that the first, second and third pusher means are driven in such a way that they are synchronised.
The device according to claim 8, characterised in that the first, second and third pusher means are driven independently by a controlled advance motor, said motors being controlled by a single programmable control unit.
The device according to claim 3, characterised in that the slat conveyor is driven at the same speed as the first pusher means, and is synchronised with the first pusher means.
The device according to claim 10, characterised in that the slat conveyor is driven by a controlled advance motor, the motor being controlled by the same programmable control unit that controls the thrust means.
The device according to claim 1, characterised in that upstream of the first surface there is a surface for arrival of the single equidistant layers.
The device according to claim 1, characterised in that downstream of the second and third surfaces there is an elevator device onto which the single layers are unloaded one on top of the other without sliding over one another.
The device according to claim 6, characterised in that the mobile surface is driven in such a way that it is synchronised with the pusher means and is moved forwards after the passage of each section of each of the transfer means.