Brush assembly for transporting preforms

Description

[0001] The invention relates to the transport of articles, and more particularly to the transport of container preforms made of plastic material such as PET.

[0002] A preform generally comprises a tubular body closed at a lower end by a hemispherical base, and a neck, usually threaded, which extends the body from an upper end thereof. Most preforms are also provided with a flange which separates the neck from the body and which facilitates the handling of the preforms.

[0003] A container manufacturing cycle requires numerous handling operations of the preform from which the container is to be manufactured. From a bulk package in a hopper (or a bowl, or any other container), the preform is successively extracted from the hopper, oriented (neck up or neck down), transferred to a heating unit (or oven), conveyed through it to undergo thermal conditioning, then again transferred to a mold to be transformed into a container by blow molding or stretch blow molding.

[0004] The transport speed of the preforms during such a cycle is not constant. In particular, the bulk packaging of the preforms in the hopper or bowl does not allow the heating unit to be fed directly from the hopper or bowl. Therefore, an intermediate zone is provided between the hopper and the heating unit where the preforms are temporarily accumulated to allow continuous feeding of the heating unit.

[0005] To achieve this accumulation, a transport device is usually used with an endless belt which drives the preforms by friction, along a predetermined path (which can be at least locally linear).

[0006] French patent FR 2 956 652 or its American equivalent US 2012 / 312661 (SIDEL PARTICIPATIONS) describes a conveyor equipped with two endless belts, at least one of which comprises, at an active part in contact with the preforms, a natural material made of leather.

[0007] This solution, which is currently commonly used, is satisfactory in that it allows the accumulation of preforms to be carried out efficiently and without damaging them.

[0008] But friction against the preforms causes, first of all, rapid wear of the leather, which requires frequent replacement of the belt.

[0009] Secondly, friction produces dust made up of fine leather particles that tend to settle on the preforms and conveyor components. Since leather is a natural material, the resulting pollution is not harmful, but it is not acceptable to allow dust to accumulate on the conveyor, which must therefore be cleaned frequently.

[0010] Furthermore IT MO20 090 60 A1 discloses a transport device according to the preamble of claim 1.

[0011] A first objective of the invention is to propose a preform transport device which allows efficient accumulation of the preforms.

[0012] A second objective of the invention is to propose a preform transport device which has better wear resistance.

[0013] A third objective of the invention is to propose a transport device which offers better resistance to heating.

[0014] To this end, a device is proposed for transporting preforms of plastic containers, this device comprising at least one endless circulating element having an external face and carrying a series of brushes which extend projecting from the external face, capable of coming into contact with the preforms to drive them by friction along a path, this device further comprising a fixed support defining a flat support face for the preforms.

[0015] The brushes efficiently drive the preforms by friction of the tips of their bristles. This friction generates little or no dust (and therefore little pollution), and the wear of the brushes remains slow when the material chosen (for example a Nylon ®< ) is resistant to wear by friction.

[0016] According to a first embodiment, where each preform has a tubular wall defining a body and a neck separated by a collar which projects radially from the wall, the device comprises a pair of rails spaced apart from each other, which jointly define at least part of the path of the preforms, these rails having coplanar bearing faces for the suspension by their collar of the preforms oriented neck upwards.

[0017] At least a portion of the brushes may extend under the rails to contact the body of the preforms.

[0018] In this first embodiment, the device comprises for example a neck guide which extends directly above the rails at a distance from them greater than or equal to a height of the neck of the preforms;

[0019] According to a second embodiment, the device comprises a plate forming a support for the preforms oriented neck down, and the brushes extend above the plate.

[0020] In this second embodiment, the device may comprise a bottom guide which extends directly above the plate, at a distance from the latter greater than or equal to an overall height of the preforms.

[0021] The device comprises, for example, two circulating elements equipped with brushes and having, along the path, parallel strands to jointly drive the preforms by friction.

[0022] The device may further comprise, over at least part of the path, a lateral guide against which the circulating element bears by an internal face opposite the external face.

[0023] Furthermore, each brush includes, for example, a row of overlapping tufts of bristles.

[0024] Likewise, each circulating element can include brushes along its entire length.

[0025] Other objects and advantages of the invention will appear in the light of the description of an embodiment, given below with reference to the appended drawings in which: there figure 1 is a perspective view from above of a preform transport device equipped with belts provided with brushes, according to a first embodiment in which the preforms are transported neck up; figure 2 is a detailed view, on an enlarged scale, of the device of the figure 1 ; there figure 3 is a perspective view showing a portion of a brush belt; the figure 4 is a cross-sectional view of the transport device, according to section plane IV-IV of the figure 2 ; there figure 5 is a detailed horizontal sectional view of the transport device, according to section plane VV of the figure 4 ; there figure 6 is a detailed view in longitudinal section of the transport device, according to section plane VI-VI of the figure 4 ; there figure 7 is a detailed cross-sectional view, on an enlarged scale, illustrating the driving of a preform by the bristles of a brush of a belt; figure 8 is a sectional view similar to the figure 4 , illustrating a second embodiment of the transport device, in which the preforms are transported neck down.

[0026] On the figure 1 a device is represented 1 preform transport (or conveyor) 2 plastic containers, for example polyethylene terephthalate (PET).

[0027] Each preform 2 has a wall 3 tubular side defining a body 4 and a collar 5. The body 4 ends, at one end opposite the neck 5, by a background 6hemispherical. Neck 5 forms a rim 7 by which the container is intended to be filled. The neck 5 can be threaded to allow a cap to be screwed on after this filling.

[0028] According to an embodiment illustrated in the figures, each preform 2 also has a collar 8 annular used to facilitate the handling of preforms 2 (and also containers formed from these preforms 2).

[0029] In the example shown, the collar 8 extends to the junction between the body 4 and the collar 5, but this configuration is not limiting. In particular, the collar could extend to an end opposite the bottom 6, so as to form the rim of the container. Similarly, the neck 5is optional, so that the preform could be limited to a smooth body terminated at one end by a base and, at an opposite end, by a collar.

[0030] In addition, the collar 8 is not necessarily continuous; it can include several disjoint angular sectors.

[0031] Classically, preforms 2 Raw injection preforms are initially stored in bulk in a container such as a hopper, from which they are extracted by known means (in a hopper, this is for example an elevator; in a bowl, this is for example a rotating plate associated with a helical rail) while being oriented neck up or neck down. At the exit of the container, the preforms 2 are poured onto a support 9 linear (such as a rail in the case of preforms 2 oriented neck up, as shown in the figure 1 ) where they move by pushing each other. In certain critical areas (particularly at the junction between the container and the support 9), systems (such as blowers) can be provided to prevent preforms from jamming 2.

[0032] The preforms 2 incorrectly oriented at the exit of the container are reintroduced into it by means of anti-rotation devices, so that the flow of preforms 2 coming out of the container is not constant. This results in the preforms 2 are not necessarily grouped on the support 9 linear, trains 10 spaced preforms can then form, as illustrated in the figure 1 . In the configuration shown, where the support 9 is horizontal, a train 10 isolated from preforms (right on the figure 1 ) does not move as much as a train 10following from the container does not push it. Alternatively, to promote the evacuation of the preforms 2 of the container, the support 9 can be tilted.

[0033] The preforms 2 leaving the container are intended to be introduced into a heating unit to undergo thermal conditioning by exposure to sources of electromagnetic radiation (e.g. infrared), so as to be softened with a view to being formed into containers by blowing or stretch blowing in a forming unit equipped with molds with the imprint of the containers.

[0034] From the entrance of the thermal conditioning unit to the forming unit, the preforms 2are individually supported by gripping means (such as spinners or clamps). The start of the forming cycle, which must produce containers at a rate of several tens of thousands of units per hour, is not subject to the presence of preforms 2, so that in the absence of one or more preform(s) in the flow of preforms leaving (and therefore entering) the thermal conditioning unit, the forming unit runs empty in the mold(s) supposed to accommodate this (these) preform(s). This results in a waste of energy and a reduction in productivity.

[0035] This is why a conveyor 1 as shown on the figure 1 is interposed between the container and the heating unit. It is an accumulation conveyor designed for, from trains 10 of preforms 2 spaced from the container, forming a continuous flow of preforms 2adjacent intended to be taken care of individually.

[0036] The conveyor 1 includes an element 11 circulating endlessly. In the example shown, the element 11 circulating is a belt, that is, a continuous band, but it could be a chain, formed by a looped series of links hinged to each other. In the following, it is assumed that the element 11 circulating is a belt, which does not exclude another embodiment (in particular a chain). As illustrated, the belt 11 runs on a pair of pulleys or gears, namely a wheel 12 motor and one wheel 13 follower. Each wheel 12, 13 is mounted in rotation on a frame 14 including a tray 15 which forms a horizontal support plane for the belt 11.

[0037] The belt 11 has a face 16internal and one side 17 external opposite. According to an embodiment illustrated in the figures, the face 16 internally is notched to engage with the teeth of the wheels 12, 13. The face 17 external forms a succession of slots 18. This configuration gives the belt 11 good flexibility.

[0038] The belt 11 is driven into motion at a noted speed V1 on the figure 7 . The belt 11 carries a series of brushes 19 which extend outward from the face 17 external. In the example shown, each slot 18 carries a brush 19, which includes a row of tufts 20 layered with hairs 21.

[0039] The belt 11 is designed to come into contact with the preforms 2 to drag them by friction along a path T.Given the flexibility of the belt 11, this journey T is not necessarily flat; it could also be curved. However, in the example shown, this path T is both flat and linear and defines a so-called longitudinal direction, which extends in a substantially horizontal plane (with, where appropriate, a slight slope). Any direction that is both horizontal and perpendicular to the longitudinal direction is called transverse.

[0040] The belt 11 is preferably positioned so that the plan 22 (materialized in dotted line on the figure 7 ) swept by the ends of the hairs 21 either offset, towards the inside of the preforms 2, of the plan 23 (materialized by the solid line on the figure 7 ) swept by the body part 4 preforms 2 closest to the belt 11.This offset results in the brush depth of pass 19 and noted P on the figure 7 , that the hairs 21 of each tuft 20 come, during the movement of the belt 11, rub against the wall 3 side of the preform 2. Due to their flexibility, the hairs 21 undergo, in contact with the wall 3, a bend that puts the hairs 21 under tension and thus increases the force exerted by each tuft 20 on the wall 3, tending to drive the preform 2 in motion. According to a preferred embodiment, the depth P pass is between 0.5 and 3 mm, and for example of the order of 1 mm.

[0041] As there is a slippage of the hairs 21 on the wall 3 lateral, part of the kinetic energy of the belt 11 is dissipated at the interface between the hairs21 and the side wall 3, so that the speed, noted V2, of preform movement 2, is less than the speed V1 belt movement 11.

[0042] A single belt could be provided 11 which would drive the preforms 2 by rubbing against them on one side only. But in such a configuration, a proper rotation of the preforms can occur 2 around their axis, likely to reduce their speed V2 of displacement.

[0043] Therefore, according to a preferred embodiment illustrated in the figures 1 , 2 , 4 And 5 , the conveyor 1 includes two straps 11 similar, arranged on either side of the route T. More specifically, the belts 11 present, along the route T, strands 24parallel (longitudinal in the illustrated example) to jointly drive the preforms 2 by friction, along diametrically opposed meridians on the preforms 2. This configuration limits the risk of inherent rotation of the preforms 2 and provides more efficient transmission of the kinetic energy of the (or each) belt 11 to preforms 2.

[0044] The material of the bristles 21 is advantageously chosen so that the frictional forces against the wall 3 lateral are high enough to transmit effectively to the preforms 2 the kinetic energy of the belt 11, so that the heating due to friction remains measured (for the benefit of better control of the thermal conditioning of the preforms 2), so that the wear of the bristles 21 by friction against the wall 3lateral is however relatively slow, and so that any scratches on the wall 3 lateral are imperceptible. Polyamides, and more particularly Nylon ®< , provide all of these advantages. The low wear of the bristles 21 guarantees a long lifespan for the (or each) belt 11.

[0045] Given the relative flexibility of the (or each) belt 11, the hairs 21 tend, under the effect of their support against the wall 3 side of the preforms 2, to transmit to the belt 11 a transverse force which, if it remained free, would tend to make it bend and consequently move the brushes away 19 preforms 2 and therefore to reduce the efforts transmitted to them.

[0046] Also, to maintain a certain transverse rigidity of the (or each) belt 11 along the wayT, and thus maintain a relatively high friction force, it is preferable to equip the conveyor 1 of a guide 25 lateral, which extends over at least part of the path T preforms 2, and against which the belt 11 leans on its face 16 internal.

[0047] According to an embodiment illustrated in the figures 2 , 4 And 5 , the position of the guide 25 is transversely adjustable. For this purpose, a part 26 horizontal of the guide 25 is provided with holes 27 oblongs into which screws are inserted 28 guide fixing 25 on the set 15. By loosening the screws 28, it is possible to move the guide transversely 25. In this way, it is possible to adjust the depth P of the pass, and therefore the friction force applied by the brushes 19to preforms 2. This adjustment also helps compensate for bristle wear over time. 21 to keep the depth P of the pass relatively constant.

[0048] As seen on the figures 2 , 4 And 8 , the conveyor 1 includes a stand 29 fixed which defines a face 30 support plane for preforms 2.

[0049] According to a first embodiment, illustrated in the figures 4 And 6 , the preforms 2, provided with a collar 8, are oriented neck up. The support 29 comes in the form of a pair of rails 31 apart from each other. The rails 31 jointly define at least part of the journey T preforms 2. The rails 31 have faces 30upper coplanar supports, allowing suspension, by their collars 8, preforms 2 oriented neck up. The spacing between the rails 31 is slightly greater than the under-neck diameter of the preforms 2. The game between the rails 31 and the body 4 preforms 2 is sufficient to allow the preforms to slide 2 without jamming, while being weak enough to prevent the collar from passing through 8 and the fall of the preforms 2.

[0050] In this embodiment, at least a portion of the brushes 19 (all brushes 19 in the example illustrated on the figure 4 ) extends under the rails 31 to come into contact with the body 4 preforms 2.

[0051] Some of the brushes 19 could however extend above the rails 31to rub against the collar 5.

[0052] In this first embodiment, the conveyor 1 preferably includes a guide 32 of collar which extends directly above the rails 31 at a distance from them greater than or equal to a height of the neck 5 preforms 2, that is to say that a gap is made between the guide 32 of collar and drinking it 7 of preforms 2. This guide 32 The neck has the function of preventing the preforms 2 do not lift and that the collars 8 preforms 2 do not overlap, so as to maintain constant (and equal to the diameter of the collar 8) the distance between two preforms 2 successive. In the illustrated example, the guide 32 neck is in the form of a bar with a rectangular section, which has a face 33 lower plane distant from the drinking edge7 preforms 2 of a few tenths of a millimeter (1 to 2 mm at most).

[0053] According to a second embodiment (illustrated on the figure 8 ), the preforms 2 are oriented neck down (and where they can possibly be without a collar, although in the example illustrated on the figure 8 ). In this case, the support 29 is presented for example in the form of a plate on which the preforms 2 rest by their drinking 7. In this configuration, the brushes 19 extend above the plate 29 and come to rub could be in the form of a pair of rails on which the preforms 2 would rest by their collar (when they have one).

[0054] In this second embodiment, the conveyor 1 can understand a guide 34background which extends directly above the plate 29, at a distance from it greater than or equal to an overall height of the preforms 2. This guide 34 limits the risk of preforms tipping forward 2 under the effect of the friction forces induced by the brushes 2. This guide 34 can be mobile to accompany the preforms along their path and thus further limit the risk of tipping. In this case, the guide 34 can be presented in the form of an endless circulating belt mounted between two pulleys.

[0055] To further prevent any lateral tilting of the preforms 2, slides 35 can be provided, positioned on either side of the body 4 and / or the collar 5.

[0056] As we see in particular on the figure 1 , the (or each) belt 11 may include brushes 19along its entire length. The placement of the brushes 19 may be vertical or, alternatively, oblique (i.e. the different tufts may be arranged in a staggered pattern). In addition, the conveyor 1 may be equipped with rollers 36 tensioners to put the (or each) belt 11 under tension and thus avoid ripples in the strand 24 along the route T and maintain a constant orientation of the hairs 21, for the benefit of the efficiency of preform training 2. Each pebble 36 tensioner is for example mounted on a plate 37 fixed in an adjustable manner transversely on the tabletop 15 of the conveyor 1.

[0057] Various alternative or additional provisions may be provided.

[0058] First, the brushes 19could be mounted on several independent superimposed belts, which would circulate for example at different speeds so as to maintain permanent friction of the brushes 19 with the wall 3 lateral of the preforms.

[0059] Second, the conveyor 1 can be equipped, as shown in the figure 1 , of one or more device(s) 38 cleaning (or decontamination) of brushes 19, operating for example by suction, by exposure to ultraviolet or ionized air. This results in a decontamination of the conveyor 1 (and therefore preforms 2), and its compliance with current health standards.

[0060] Third, the conveyor 1 can be equipped with at least one preform ejector, allowing extraction from the flow of preforms circulating in the conveyor 1any preform that is incorrectly oriented and risks causing blockage or intermingling of the preforms 2 along the route, likely to damage or break at least one of the conveyor components 1. This ejector would, for example, be in the form of a mobile section of the support 29, which would form a retractable trapdoor controlled by the detection of one or more incorrectly oriented preform(s).

Claims

1. Device (1) for transporting preforms (2) of containers made of plastic, of the type of preforms that are intended to be transformed into containers by blow-moulding or stretch-blow-moulding, which preforms are made of plastic and each have a tubular wall (3) defining a body (4) and a neck (5) that are separated by a collar (8) that protrudes radially from the wall (3), said device (1) comprising an endless circulating element (11) that has an external face (17) and bears a series of brushes (19) that protrude from the external face (17), which are able to come into contact with the preforms (2) so as to drive them by friction along a path (T), the device (1) comprising a pair of rails (31) that are spaced apart from one another, which jointly define at least a part of the path (T) of the preforms (2), these rails (31) having coplanar bearing faces (30) for the suspension, by their collar (8), of the preforms (2) oriented neck up, the belt (11) having an internal face (16) opposite the external face (17), said device (1) also comprising a neck guide (32) that extends vertically in line with the rails (31) at a distance therefrom that is greater than or equal to a height of the neck (5) of the preforms (2), the guiding of the preforms by the neck guide (32) preventing the collars (8) of two successive preforms from overlapping, and a lateral guide (25) on which the circulating element (11) bears via the internal face, over at least a part of the path (T), characterized in that the external face (17) of the belt (11) forms a succession of crenellations (18), each crenellation (18) bearing a brush (19), and in that a horizontal part (26) of the guide (25) is provided with oblong holes (27) into which screws (28) are introduced for fastening the guide (25) to the plate (15) so as to transversely adjust the position of the guide (25).

2. Transport device (1) according to Claim 1, characterized in that at least some of the brushes (19) extend beneath the rails (31) so as to come into contact with the body (4) of the preforms (2).

3. Transport device (1) according to Claim 1, characterized in that all the brushes (19) extend beneath the rails (31).

4. Transport device (1) according to either one of Claims 1 and 2, characterized in that some of the brushes (19) extend above the rails (31) so as to rub against the neck (5).

5. Transport device (1) according to Claim 1 or 2, characterized in that the neck guide (32) is in the form of a bar of rectangular section, which has a flat lower face (33) that is a few tenths of a millimetre away from a mouth (7) of the preforms (2).

6. Transport device (1) according to any one of Claims 1 to 5, characterized in that it comprises two circulating elements (11) that are provided with brushes (19) and have, along the path (T), parallel strands (24) for jointly driving the preforms (2) by friction.

7. Transport device (1) according to one of the preceding claims, characterized in that each brush (19) comprises a row of superposed tufts (20) of bristles (21).

8. Transport device (1) according to one of the preceding claims, characterized in that each circulating element (11) comprises brushes (19) over its entire length.

9. Transport device (1) according to any one of the preceding claims, characterized in that the installation of the brushes (19) is vertical.

10. Transport device (1) according to any one of Claims 1 to 8, characterized in that the installation of the brushes (19) is oblique, i.e. the various tufts can be installed in a staggered manner.

11. Transport device (1) according to any one of the preceding claims, characterized in that the brushes (19) are mounted on a plurality of independent superposed belts.

12. Transport device (1) according to Claim 11, characterized in that the independent superposed belts circulate at different speeds so as to maintain permanent friction of the brushes (19) with the lateral wall (3) of the preforms.

13. Transport device (1) according to any one of the preceding claims, characterized in that it comprises one or more devices (38) for cleaning or decontaminating the brushes (19).

14. Transport device (1) according to Claim 13, characterized in that the one or more cleaning or decontaminating devices (38) operate by suction, by exposure to ultraviolet radiation or to ionized air.

15. Transport device (1) according to any one of the preceding claims, characterized in that it comprises at least one preform ejector.