EP2174870B1

EP2174870B1 - Preform distributor for drop loading an open container with preforms in bulk

Info

Publication number: EP2174870B1
Application number: EP20080017872
Authority: EP
Inventors: Thomas Barry
Original assignee: La Seda de Barcelona SA
Current assignee: La Seda de Barcelona SA
Priority date: 2008-10-13
Filing date: 2008-10-13
Publication date: 2011-09-14
Anticipated expiration: 2028-10-13
Also published as: WO2010043303A1; EP2174870A1; ES2370738T3

Description

Field of the invention

The present invention relates to the field of bulk storage of plastic preforms in a container for handling and transport purposes. The invention relates to a novel solution for improving the drop loading of an open container with preforms in bulk, in order to increase the number of preforms inside the container.

Background of the invention

Receptacles made of polyester, for example bottles made of polyethylene terephthalate (PET), are conventionally manufactured in two successive stages: in a first stage, a thermoplastic preform is made by injecting one or more thermoplastic resins into a mold; in a second stage, the preform is blown and stretched in a blow mold so as to form the receptacle. These two stages are not necessarily performed immediately in line one after the other, and indeed they can be performed on different production sites. Under such circumstances, it is necessary to store the preforms on the site where they are produced so that they can subsequently be taken to the blowing machine which might possibly be situated on a different production site that is remote from the site where the preforms are produced.
A well-known storage method consists in drop loading a container with the preforms in bulk. The container can be made of various materials (metal, cardboard, ... ), and can have a variety of shapes and sizes. The preforms are inserted from above, dropping under gravity into the inside of the open container.
One major drawback of that method of drop loading lies in poor use of the storage volume of the container, which amounts to low packing density, i.e. a small number of preforms being stored per unit volume. In practice, when a container is drop loaded with preforms, it is indeed observed that a convex dome or pyramid forms at the top portion of the pile of preforms, where such a dome or pyramid is characteristic of poor utilization of storage volume. However, for manifest economic reasons, associated mainly with the cost of transporting preforms, it is naturally preferable to have as large as possible a number of preforms in a container.
At least two different technical solutions have already been proposed in the past in order to improve the packing density of preforms that are stored in bulk in a container.
A first solution is described for example in PCT application WO 95/18043 and consists in using a special apparatus for shaking the container in order to rearranged the preforms that are stored in bulk inside the container. This solution presents the drawback of requiring a special complex and expensive equipment for shaking the container.
A second solution described in US patents n° 6,820,396 and n° 7,093,411 consists in applying a lubricant on the outer surface of each preforms, for example by spraying silicone oil onto the preforms, in order to render the preforms more slippery before storing the preforms in bulk in a container. This solution presents also the drawback of requiring a special complex and expensive equipment for applying the lubricant on the preforms. A further drawback is that at least the outer surface of the preforms is soiled by the lubricant.
In order to improve the packing density of preforms in a container, proposals have also been made in the past to store preforms, not in bulk, but in ordered manner, by stacking preforms so that they are oriented in such a manner that the preforms in a given row point in the opposite direction to the preforms in an adjacent row. Such a solution is described in particular in US patent n° 5,555,706 . This solution does indeed enable the volume occupied by the preforms inside the container to be optimized in comparison with bulk storage. However, it presents the drawback of requiring special equipment that is complex and expensive in order to store the preforms in the container.

Objective of the invention

An objective of the present invention is to provide a novel solution for drop loading a container with preforms in bulk, which solution enables packing density (i.e. the number of preforms per unit volume) to be increased and which is simple and does not require the use of a complex and costly equipment compared with the aforesaid solutions of the prior art.

Summary of the invention

This objective is achieved by means of the preform distributor that is defined in claim 1.
The invention also relates to an assembly defined in claim 12 and comprising an open container for storing preforms in bulk and the said preform distributor, said container comprising a top filling opening, and said preform distributor being positioned above the top filling opening of the container.
The invention further relates to an apparatus defined in claim 14 for loading a container with preforms in bulk, and comprising the aforesaid assembly, and dropping means for dropping preforms unevenly above the preform distributor of the said assembly.
The invention further relates to a method defined in claim 18, for loading an open container with preforms in bulk, and comprising the following successive steps:

positioning the aforesaid preform distributor above the top filling opening of an open container,
dropping preforms above the said preform distributor in such a way that the preforms are unevenly distributed above the preform distributor, in order to fill the container with said preforms in bulk.

Brief description of the drawings

Other characteristics and advantages of the invention will appear more clearly on reading the following description a preferred embodiment of the invention, which description is given by way of non-limiting example and with reference to the accompanying drawings, in which:

Figure 1 is schematic side view of an apparatus of the invention for drop loading preforms in bulk in a container,
Figure 2 is schematic top view of the apparatus of figure 1,
Figure 3 is a top view of an open container fitted with a distributor device of the invention,
Figure 4 is a section view of the assembly of figure 3 in plane IV-IV
Figure 5 is a section view of the assembly of figure 3 in plane V-V.

Detailed description

Referring to figures 1 and 2, an apparatus for drop loading plastic preforms P in bulk in a container comprises an assembly 1 constituted by an open container 2 fitted with a preform distributor 3, and a conveyor 4 for transporting the preforms P between an upstream unit 5 and the assembly 1.
The upstream unit 5 is for example a standard injection machine that is being used for manufacturing the plastic preforms P. The preforms manufactured by the said injection machine are ejected at the outlet of the machine 5 onto the conveyor 4, and are transported by the said conveyor 4 to the assembly 1, in order to be dropped in bulk into the open container 2 of the assembly 1.
The preform distributor 3 is an add-on piece of equipment that is removably mounted on the top part of the open container 2, and is used for obtaining a more even filling of the preforms inside the container 2. As a result, the use of this preform distributor 3 enables to increase the number of preforms that are stored in bulk in the container, in particular without using a costly vibrating system for shaking the container. Once the container 2 is being filled with preforms P, the preform distributor 3 is removed from the container 2, and can be used for drop loading another open container. Once loaded with preforms P in bulk, the container 2 is then closed, and is ready to be temporarily stored in a warehouse or to be transported to another production site where the preforms are used for manufacturing stretched-blow molded receptacles, like for example plastic bottles.
A preferred embodiment of an assembly 1 (i.e. a preform distributor 3 mounted on a container 2) is shown on figures 3 to 5 and is now going to be described in details in reference by way of a non-limiting example.
The open container 2 is a standard container that is commonly used for storing preforms P in bulk, and comprises a bottom 20 and circumferential sidewall 21 that delimits an enclosure for the preforms P. This container 2 can be made of any kind of material, including notably cardboard, metal, or plastic. The upper circumferential edge 21a of the sidewall 21 of the container 2 surrounds a top filling opening 22 for the introduction of preforms into the container. This open container 2 can be closed with a standard removable closure (not shown) suitable to be removably fitted on the upper edge 21a of the sidewall 21.
In the particular example shown on the attached figures, the container 2 has a rectangular shape, but the invention is obviously not limited to such a particular container shape, and can be also practiced with any other container shape, and for example with a container having a square shape, a round shape, an octagonal shape,.... .
The preform distributor 3 can be made of any kind of material, but is preferably a light piece of equipment, and is for example made of plastic, in order to facilitate the handling of the preform distributor 3 by an operator.
The preform distributor 3 comprises a frame 30 whose shape is adapted to the shape of the container, i.e. to the geometry of the upper circumferential 21a of the sidewall 21a of the container. This frame 30 is made of four walls 300 that are assembled together, for example by welding. The said frame walls 300 have a base 300a (figures 4 and 5) that is specifically designed in such a way that the frame 30 can be removably fitted on the upper edge 21a of the circumferential sidewall 21 of the container 2. The frame walls 300 are inclined downwardly and form a hopper of small height, in order to deflect any preform that would be dropped above a frame wall 300, towards the top filling opening 22 of the container 2.
The preform distributor 3 further comprises deflecting means 31. In the example illustrated on the figures, said deflecting means 31 comprises two main deflecting walls 310a and 310b that are spaced apart and delimit a central opening 32. Said two main deflecting walls 310a, 310b are substantially symmetrical one to the other in relation to a main central vertical plane A (figure 3) and are assembled at their extremities with two opposite frame walls 300, for example by welding, in such a way that they are inclined downwardly and away from each other. The central opening 32 extends on both sides of main central vertical plane A. The deflecting wall 310a delimits with the frame 30 a first lateral opening 33a and the deflecting wall 310b delimits with the frame 30 a second lateral opening 33b. The central opening 32 is thus positioned between the first and second 33b lateral openings 33a, 33b. Each lateral opening 33a, 33b extends on both sides of a secondary central vertical plane B that is perpendicular to the said main central vertical plane A.
The central opening 32 is designed for enabling preforms to pass through the distributor. This central opening 32 is used for enabling some preforms to be dropped into a central part of the container 2.
Each lateral opening 33a, 33b is also designed for enabling preforms to pass through the distributor. The inclined upper surface 310c of each main deflecting wall 310a and 310b forms a deflecting surface that is suitable for deflecting preforms that are dropped above said deflecting wall into the corresponding lateral opening 33a or 33b.
Each main deflecting wall 310a, 310b carries also a set of two auxiliary deflecting walls 311a, 311b. Each auxiliary deflecting wall 311a, 311b comprises a deflecting surface 311c (figure 3) that is positioned above and is substantially perpendicular to the upper deflecting surface 310c of the corresponding main auxiliary deflecting wall 310a, 310b. In the particular example of figures 3 to 5, each auxiliary deflecting wall 311a, 311b is a tab that is simply obtained by cutting and folding at approximately 90° a small part of the deflecting wall 310a, 310b. In another variant, the auxiliary deflecting walls 311a and 311b could be add-on pieces fixed to the main deflecting walls 310a, 310b.
The two auxiliary deflecting walls 311 a or 311 b of each set are inclined downwardly and away from each other. Preferably, but not necessarily, the two auxiliary deflecting walls 311a or 311b of one set are substantially symmetrical one to the other in relation to the said secondary central vertical plane B. The two auxiliary deflecting walls 311a or 311b of each set are suitable for deflecting the preforms that are sliding onto the upper deflecting surface 310c of the main deflecting wall 310a or 310b away from the said secondary central vertical plane B.
More particularly, in the embodiment of figures 3 to 5, the frame 30 of the preform distributor 3 has four corners 30a, 30b, 30c, 30d, and the auxiliary deflecting walls 311a, 311b are designed for deflecting preforms towards each corner of the frame. To this end, the deflecting surface 311c of each auxiliary deflecting wall 311 a 311 b is oriented towards one of the corners 30a, 30b, 30c, 30d of the frame.
As shown on figure 2, the conveyor 4 is positioned in relation to the preform distributor 3 in such a way that the conveying surface 4a of the conveyor 4 is substantially centred with the central opening 32 of the distributor device 3. The conveying direction of the preforms on the conveyor 4 is referenced by arrow T on the drawings, and is substantially parallel to the main vertical plane A. The downstream end 4b (figure 1) of the conveyor 4 is positioned above the preform distributor 3, and more preferably above the centre of the central opening 32 of the distributor device, in such a way that the preforms P are dropped into the distributor device 3 at the downstream end of the conveyor 4.
In reference to figure 2, the width (L) of the conveying surface 4a of the conveyor 4 is smaller than the width (D) of the top filling opening 22 of the container 2, but is wider than the smallest horizontal dimension (d1) of the central opening 32 between the two main deflecting walls 310a, 310b, i.e. in this example the smallest distance (d1) between the two upper edges 310d of the two main deflecting walls 310a, 310b. Preferably, but not necessarily, the width (L) of the conveying surface 4a of the conveyor 4 is substantially equal to the widest horizontal dimension (d2) of the central opening 32, i.e. this example the smallest distance (d2) between the two lower edges 310e of the two main deflecting walls 310a ,310b.
In operation, preforms P are ejected at the outlet of the upstream unit 5 onto the conveying surface 4a of the conveyor 4 and are unevenly distributed over the width (L) of the conveying surface 4a. The preforms P are transported by the conveying surface 4a to the downstream end 4b of the conveyor 4 where they are dropped above and fall down into the preform distributor 3. Depending of their position along the width (L) of the conveyor 4, some preforms (like for example the preform referenced P2 on figure 2) fall down inside the container 2 directly through the central opening 32 of the preform distributor 3, without being deflected by the deflecting means 31 of the preform distributor 3. The other preforms (like for example the preforms referenced P1 or P3 on figure 2) fall down onto the main deflecting walls 310a, 310b and are deflected, by the main deflecting walls 310a, 310b and by the auxiliary deflecting walls 311a, 311b, away from the central opening 32 and into the lateral openings 33a, 33b of the preform distributor 3. Theses preforms are thus deflected into the corner 2a, 2b, 2c 2d of the container 2. Thanks to this preform distributor device 3, an even distribution of the preforms inside the container 2 is obtained, and the building of the usual central dome or pyramid of preforms can be advantageously avoided, without shaking the container 2. The number of preforms inside the container is thus significantly increased, compared to the same operation of drop loading of the container 2, but without the distributor device 3.
The scope of invention is not limited to the particular embodiment that has been described in reference to the appended figures, but is defined by the appended claims. In particular, but not only, within the scope of the invention, the preform distributor 3 is not necessarily carried by the container 2 during the drop loading operation. In another variant the preform distributor device 3 can be indeed supported above the container by any other mechanical support means that are distinct from the container.

Claims

A preform distributor (3) for improving the drop loading of an open container (2) with preforms (P) in bulk, said distributor comprising a central opening (32), at least two lateral openings (33a ; 33b), and deflecting means (31) for deflecting preforms that are dropped above said deflecting means (31) into the lateral openings (33a ; 33b), and wherein the central opening (32) and each lateral opening (33a, 33b) are designed for enabling preforms to pass trough the distributor.
The preform distributor of claim 1, wherein the deflecting means comprise two main deflecting walls (310a ; 310b) that are spaced apart, and wherein said two main deflecting walls are inclined downwardly and away from each other, one (310a) of the main deflecting walls being provided for deflecting preforms into one lateral opening (33a), and the other deflecting wall (310b) being provided for deflecting preforms into the other lateral opening (33b).
The preform distributor of claim 2, wherein the two main deflecting walls (310a ; 310b) are substantially symmetrical one to the other in relation to a main central vertical plane (A).
The preform distributor of any one of claims 1 to 3, wherein the central opening (32) extends on both sides of a main central vertical plane (A), wherein each lateral opening (33a, 33b) extends on both sides of a secondary central vertical plane (B) that is perpendicular to the said main central vertical plane (A), and wherein the said deflecting means (31) further comprise auxiliary deflecting means (311a ; 311b) for deflecting the preforms away from said secondary central vertical plane (B).
The preform distributor of claim 4, wherein the said auxiliary deflecting means (31) comprise a set of two auxiliary deflecting walls (311a ; 311b) for each lateral opening (33a ; 33b) and wherein the two auxiliary deflecting walls of each set are inclined downwardly and away from each other and are suitable for deflecting the preforms away from the said secondary central vertical plane (B).
The preform distributor of claim 5, wherein each auxiliary deflecting wall (311a, 311b) is carried by one main deflecting wall (310a : 310b).
The preform distributor of claim 5 or 6, wherein the two auxiliary deflecting walls (311a ; 311b) of one set are substantially symmetrical one to the other in relation to the said secondary central vertical plane (B).
The preform distributor of any one of claims 5 to 7, wherein each main deflecting wall (310a, 310b) comprises an upper deflecting surface (310c), and wherein each auxiliary deflecting wall (311a; 311b) comprises a deflecting surface (311c) that is positioned above and is substantially perpendicular to the upper deflecting surface (310c) of one main auxiliary deflecting wall (310a, 310b).
The preform distributor of any one of claims 4 to 8, comprising a frame (30) having four corners (30a, 30b, 30c, 30d), and wherein the auxiliary deflecting means (311a ; 311b) are designed for deflecting preforms towards each corner of the frame.
The preform distributor of claim 9, wherein each auxiliary deflecting wall (311a; 311b) comprises a deflecting surface (311c) that is oriented towards one corner of the frame.
The preform distributor of any one of claims 1 to 10, comprising a frame (30) that is suitable to be removably fitted on the upper part of an open container (2), and that carries the deflecting means (31).
An assembly (1) comprising an open container (2) for storing preforms in bulk, and a preform distributor (3) defined in any one of claims 1 to 11, wherein said container (2) comprises a top filling opening (22), and wherein said preform distributor (3) is positioned above the top filling opening (22) of the container.
The assembly of claim 12, wherein the preform distributor (3) is carried by the container (2).
Apparatus for loading a container with preforms in bulk, comprising the assembly of claim 12 or claim 13, and dropping means for dropping preforms unevenly above the preform distributor (3) of the said assembly (1).
The apparatus of claim 14, wherein the dropping means comprises a conveyor (4) for transporting preforms and having a downstream end (4b) that is positioned above the preform distributor (3).
The apparatus of claim 15, wherein the conveyor (4) comprises a conveying surface (4a) that is centred with the central opening (32) of the preform distributor (3).
The apparatus of claim 16, wherein the width (L) of the conveying surface (4a) of the conveyor (4) is smaller than the width (D) of the top filling opening (22) of the container (2), and is wider than the smallest horizontal dimension (d1) of the central opening (32) of the preform distributor (3).
Method of loading an open container (2) with preforms in bulk, comprising the following successive steps :
- positioning a preform distributor (3) defined in any one of claims 1 to 11 above the top filling opening (22) of an open container (2),

- dropping preforms (P) above the said preform distributor (3) in such a way that the preforms are unevenly distributed above preform distributor (3), in order to fill the container (2) with said preforms in bulk.
The use of the preform distributor (3) of any one of claims 1 to 11 for drop loading an open container (2) with preforms (P) in bulk.