WO2001066447A1

WO2001066447A1 - Method for transporting articles, and air conveyor for implementing same

Info

Publication number: WO2001066447A1
Application number: PCT/FR2001/000658
Authority: WO
Inventors: Carlos Rodrigues; Joël TRENEL
Original assignee: Netra Systems
Priority date: 2000-03-08
Filing date: 2001-03-06
Publication date: 2001-09-13
Also published as: FR2806068A1; AU2001242542A1

Abstract

The invention concerns a method for transporting articles (B), in particular plastic bottles, under the action of air jets in a specific transporting direction (SDT), and between two guide rails (1) enabling the articles to be suspended, which consists in applying on the articles air jets for transporting them inclined rearwards relative to the transporting direction (SDT). More particularly, it consists in generating towards the articles and over the whole length of the conveyor low reverse air jets (R) oriented in the direction opposite to the direction transporting (SDT) the articles, and which are preferably also oriented upwards so as to enable the articles to be airborne.

Description

METHOD FOR TRANSPORTING ARTICLES, AND AIR CONVEYOR FOR CARRYING OUT SAID METHOD

The present invention relates to the field of pneumatic transport of articles guided in their movement between two guide rails, allowing their suspension, and more particularly of light articles such as for example empty plastic bottles or flasks, 0 preforms etc.

To transport light articles, and more particularly plastic bottles or the like, it is currently known to use air conveyors equipped with blowing means making it possible to create a plurality of air jets oriented on the articles in their direction. of 5 transport.

For articles which can be suspended, such as for example plastic bottles having at their neck a collar, use is more particularly of air conveyors which are equipped with two guide rails opposite, more commonly called 0 under-neck guides, between which the articles are guided and transported while being suspended by means of their flange or the like. This type of conveyor is described for example in patent US-A-4,284,370 or also in patent US-A-5,161, 919. It implements a main air duct, commonly called a plenum and extending along the path 5 of the articles, and a blowing channel communicating with the main air sheath via blowing slots or the like. The main duct is supplied with air, for example by means of several fans judiciously distributed over its entire length; this air is evacuated by the blowing slots in the form of a plurality of air jets 0 making it possible to propel the articles along the blowing channel.

In US-A-4,284,370, the blowing channel has a section rectangular and the blowing slots are arranged above the guide rail, which makes it possible to propel the articles by blowing above their flange. In patent US-A-5,161,919, the blowing channel has the shape of an inverted V, and the blowing slots are arranged below the guide rail, which makes it possible to propel the articles by blowing under their collar.

The aforementioned air conveyors have several drawbacks.

During their transport, the articles tend to oscillate longitudinally with respect to the vertical in an alternating forward / backward movement (first drawback), which affects the quality of the conveyance, and which moreover causes risks of blocking of the articles, such as for example a front or rear blocking.

Also, during their transport along their guide and suspension rails (guides under neck), the articles (second disadvantage) undergo friction forces which are detrimental to the conveyability of the articles, and which in addition can cause wear over time of the guide rails and / or marking or deterioration of the parts of the articles in contact with the guide rails.

The main object of the present invention is to provide a simple solution which overcomes the first drawback above, and thereby improves the conveyability of the articles transported in an air conveyor. This object is achieved by the method of claim 1.

In a first particular variant embodiment, the maintenance of the articles in an inclined rearward position during transport is obtained by generating, in the direction of the articles, reverse air jets oriented in the direction opposite to the direction of transport (SDT) of the items.

In a second particular variant embodiment, the maintenance of the articles in a tilted rearward position during transport is obtained by generating, towards the articles, jets of upper and lower transport air, oriented towards the front in the direction transport (SDT) of the articles, the lower air jets being generated at a level below the level of the upper air jets. In this variant, the adjustment of the backward inclination of the articles is obtained by judiciously adjusting the air power differential between the upper and lower air jets. In a preferred embodiment, which also overcomes the second drawback mentioned above, the articles are supported by means of a plurality of lower air jets which are generated below the path of the articles and which are directed upwards.

In the preferred embodiment mentioned above, the effect of the lower air jets is to apply an upward aeraulic thrust force on the articles being transported, which makes it possible to support them relative to their guide rails, thereby reducing the forces of friction undergone by the articles in contact with the guide rails. Depending on the air power involved, the articles can be lifted relative to the guide rails, while remaining in contact with the guide rails. With sufficient air power, it is possible to obtain a slight detachment of the articles relative to the guide rails; in this case, the articles are no longer strictly speaking suspended on the guide rails during transport, but are simply guided laterally by the guide rails, and it is preferable to provide a high stop to avoid in particular the risks of blocking articles by rising and wedging between the guide rails, as provided for example in international patent application WO-A-9910263. The force applied to the articles to keep them in a tilted back position and avoid forward rocking phenomena can be an aeraulic (air jets) or mechanical (frictional or longitudinal lower stop) pushing force, the two types of force possibly being combined. In a first embodiment, the lower air jets are also oriented towards the rear in the opposite direction to the direction of transportation of items. In this variant, the lower air jets thus have the effect of applying to the articles an aeraulic thrust force allowing the articles to be tilted backwards, which makes it possible to limit and even even avoid rocking towards the front of the articles during transport, and improve the transport stability of the articles. These lower air jets thus ensure by themselves the double function of lift and tilt backwards of the articles. It is up to the person skilled in the art to adapt the power of these lower air jets case by case to obtain the required transport stability. In a second alternative embodiment, the lower air jets are oriented forward in the direction of transport of the articles. In this case, they participate in the propulsion of the articles in the direction of transport. This variant is for example, but not exclusively, advantageous to implement in the conveyor portions forming a rise.

Another subject of the invention is an air conveyor which allows the implementation of the aforementioned method. This air conveyor is known in that it comprises two guide rails on which the articles can be suspended, and aeraulic means making it possible to propel, under the action of air jets, the articles between the two guide rails and in a given direction of transport.

Characteristically according to the invention, the aeraulic means are designed to apply to the articles aeraulic thrust forces which make it possible to maintain them in a position inclined towards the rear relative to their direction of transport.

Other characteristics and advantages of the invention will appear more clearly on reading the description below of two alternative embodiments of an air conveyor in accordance with the invention, which description is given by way of non-limiting example and with reference to the attached drawings in which:

- Figure 1 is a cross-sectional view of a first variant an air conveyor with lower longitudinal guide, reverse blowing duct at the bottom, and side blowing for propelling the articles,

FIG. 2 is a schematic representation, seen from the side, of the conveyor of FIG. 1,

FIG. 3 is a cross-sectional view of a second variant of an air conveyor according to the invention,

- And Figure 4 is a schematic representation, side view, of the conveyor of Figure 3. There is shown in Figure 1 a first embodiment of an air conveyor used for transport, under the action of jets of empty plastic bottles B. Usually, this air conveyor comprises two parallel guides under neck 1, which extend over the entire length of the conveyor, and which form two parallel guide rails for bottles B More particularly, in the example of FIG. 1, the bottles B are introduced into the conveyor so that their collar C is positioned above the guides under neck 1; the spacing between the two guides under neck 1 is sufficiently small relative to the dimension of the flange C so that the guides under neck 1 allow the suspension of bottles B by means of their flange, that is to say allow the bottles to be held vertically by their collar. More generally, the bottles could be retained vertically by any part capable of serving as a bearing zone, and in particular by any portion forming a protuberance, or on the contrary forming an annular groove as illustrated in FIG. 1 of French patent FR-B -2,531,048.

In the particular embodiment of FIG. 1, the guides under the neck 1 are rigidly fixed on a profile 2 forming a closed cowling with the exception of its underside which is open, this cowling making it possible to protect the neck of the bottles B above their collar C. With reference to FIGS. 1 and 2, the transport of the bottles in the direction of transport (SDT) along the guides under neck 1 is carried out exclusively by lateral blowing by means of transport air jets J which are generated below the guides under neck 1. More particularly, for the formation of transport air jets J, the conveyor comprises two lateral blowing ducts 3, which are arranged on either side of the path of the bottles B and which are intended to be supplied with pressurized air.

Each lateral blowing sheath 3 comprises a longitudinal face 3a which is oriented towards the bottles and in which are formed slots or blowing openings 4 judiciously distributed over the entire length of the blowing sheath 3. When the blowing sheath 3 is supplied in pressurized air, the air escapes from the inside of the sheath 3 towards the outside by the blowing slots 4, in the form of the transport air jets J directed on the bottles in the direction of transport (SDT). It is up to the person skilled in the art to adapt the geometry and the orientation of the blowing slots 4 as well as the space between slots 4.

For the supply of pressurized air to the ducts 3, the conveyor comprises a plurality of fans (not shown) judiciously distributed along the length of the conveyor, the outlet of each fan being locally connected to a distribution panty 5. Each distribution panty 5 is connected locally with each blowing duct 3 by a fitting 6. Each fitting 6 is equipped with a damper 7 or any other equivalent means allowing adjustment of the air flow entering the blowing duct 3, which allows to adjust the air pressure inside and over the entire length of each duct 3. By means of the registers 7, it is thus possible to control the aeraulic power of the transport air jets J, and even see d '' interrupt these jets of transport air. The air conveyor is equipped in the lower part with a lower blowing duct 8 which extends along and below the path of the bottles B. This sheath 8 is designed to be supplied with pressurized air, from each distribution pant 5, and via a connector 9. Each connector 9 is equipped with a register 10, allowing an adjustment of the air flow entering the lower blowing duct 8, which makes it possible to adjust the air pressure inside and over the entire length of the lower blowing duct 8.

The lower blowing sheath 8 is closed in the upper part by a flat sheet 11, which forms the upper longitudinal face 8a of the sheath 8, and in which a row of blowing slots 12 is formed. These slots 12 have a geometry and a orientation such that once the sheath 8 is supplied with air, the air under pressure inside the sheath 8 escapes through the blowing slots 12 in the form of a plurality of reverse air jets R which are directed both upwards and rearwards of the conveyor, that is to say in the direction opposite to the direction of transport (SDT) of the bottles.

FIG. 2 shows schematically by the arrow V, a speed vector of the reverse air jets R at the outlet of the blowing slots 12. The air speeds at the outlet of the slots 12 have a vertical component (Vz) and a horizontal component (Vh), which depend on the geometry of the slots and on the air pressure inside the lower blowing duct 8.

The reverse air jets R located immediately downstream of a bottle B apply aeraulic thrust forces on the visible front face F of the bottle. The horizontal component of these aeraulic thrust forces contributes to tilt the cylinder backwards with respect to the vertical. The bearing surface of this visible face being large, a low air force is sufficient to tilt the bottle backwards. The reverse reverse air jets R which are generated at the base of the bottle apply aeraulic thrust forces to the underside of the base of the bottle, and contribute essentially by their vertical component to obtaining of the bottle's lift effect. The reverse air jets R generated at the bottom face of the base of the bottle also contribute by their horizontal component to the tilting effect towards the rear of the bottle, but their contribution to this effect is more weak than that of the reverse air jets R generated downstream of the bottle.

We understand in light of the above explanations, that during transport, under the action of the transport air jets J from the blowing slots 4, a bottle B is propelled in the direction SDT (Figure 2). Under the action of the reverse reverse air jets R, the bottle B is simultaneously (1 ^st effect) lifted from its support points on the guides under neck 1, and (2 ^nd effect) kept inclined towards the rear relative to the vertical at conveying angle A '(bottle in solid line in Figure 2).

Depending on the air power used for a given type of blowing slots 12, a more or less significant detachment of the bottle B is obtained during transport relative to the guides under neck 1, which reduces or even cancels friction, and thereby reduces the wear phenomena of the guides 1 and improves the conveying. With sufficient air power (adjusted by means of registers 10), it even becomes possible to transport the bottles, by lifting them slightly relative to the guides under neck 1, the flange C of the bottles being almost no longer in contact with the guides under -col 1.

By increasing the horizontal component (Vh) of the reverse air jets R, by a greater opening of the registers 10, the conveying angle A ′ of the transported bottles is increased. This forced inclination towards the rear of the bottles by the reverse air jets R makes it possible to obtain good transport stability of the bottles, since the risks of front / rear oscillations of the bottles are limited.

According to an advantageous characteristic, the air conveyor of FIGS. 1 and 2 is also equipped with a lower longitudinal guide 13, which extends along the path of the bottles, over all or part of the length of the conveyor, and which is positioned near and above the lower blowing duct 8.

In the example illustrated, this guide 13 is produced in the form of two identical longitudinal sections 14 mounted parallel to each other, and each having an internal face oriented towards the bottles, in the form of a guide wall 15, which in the preferred embodiment of Figure 1 is planar. These two sections 14 are mounted so that the guide walls 15 are opposite one another and each form a plane PP inclined relative to the vertical of an angle E. The two planes PP formed by each guide wall 15 converge towards each other downwards. This lower longitudinal guide 13 is mounted on the conveyor vertically and below the guides under the neck 1 so that the axis of symmetry of this guide 13 coincides with the axis of symmetry SS of the conveyor. Preferably, the two sections 14 of the guide 13 are made of a material with a low coefficient of friction and for example of plastic material such as PE (Polyethylene).

When a bottle B is suspended on the two guides under the neck by means of its collar C, under the action of its own weight and in the absence of reverse air jets R, it comes to its base in contact with the two guide walls 15, being inclined by a minimum conveying angle A (see bottle in dotted lines in FIG. 2). This minimum conveying angle A is fixed by adjusting the vertical distance which separates the guides under neck 1 and the lower longitudinal guide 13. The lower longitudinal guide 13 constitutes a mechanical safety device making it possible to prevent any risk of tilting of the bottles towards the front transported. Thus, whatever the power of the reverse air jets R, and in particular in the event of a momentary and / or localized failure of the reverse air jets R, it is certain to prevent rocking of the bottles towards the front, and thus avoids any risk of forward / backward rocking of the bottles. However, during transportation, under normal non-breaching action and jets ^of lower air inverse R, the bottles are transported by being inclined rearwardly from a conveying angle A 'the value of which may fluctuate but which is preferably always slightly greater than the value of the minimum conveying angle A guaranteed by the longitudinal guide 13. Thus, during normal transport, the bottles at their base are not or almost not in contact with this guide 13. It is therefore understood , that the implementation of this longitudinal guide 13, although preferred, is however optional in the context of the variant of FIGS. 1 and 2. Preferably, the blowing slots 12 are aligned in the direction of the length of the conveyor under the shape of a row of slots which is centered on the axis of symmetry (SS) of the conveyor, that is to say essentially the axis of symmetry between the two guides under neck 1. As a result, the jets reverse air s R come to apply on the base of the bottles B an aeraulic thrust force, which tends to tilt the bottles B backwards essentially in a longitudinal vertical plane passing through the axis of symmetry (SS) of the conveyor, and which does not little or no tendency to tilt the bottles sideways.

To prevent the bottles from leaving the longitudinal guide 13 in the event of lateral rocking of the bottles, the conveyor of FIGS. 1 and 2 is also equipped with lateral guides 16, which are mounted along the conveyor on either side of the path of the bottles B. The risk of lateral rocking of the bottles during transport is particularly high in the curved portions of the conveyor (turns). Indeed, in these curved portions, the bottles tend, under the effect of centrifugal force, to shift laterally outward.

In a simplified alternative embodiment of the invention, one could remove the lower longitudinal guide 13, ^and do use such that the side guides 16. But in this case, the conveyor can no longer guarantee a minimum conveying angle A , in the event of failure of the reverse air jets R. In the particular variant embodiment of FIG. 1, the two guide walls 15 form a plane PP inclined at an angle E being substantially equal to 45 °. This characteristic, although preferred according to the invention, is however not limitative of the invention. In another embodiment, this angle could be more or less important. It is furthermore not essential that the two guide walls 15 form a plane, these walls possibly in other variants having any curved shape, in particular convex or concave.

Another possible use of the reverse air jets R in the conveyor of FIGS. 1 and 2 is to achieve, in a given portion of the conveyor, an aeraulic slowing down of the bottles, and even even an aeraulic stopping of the bottles, or even to perform an unlocking. of a bottle by reversing the aeraulic thrust force applied to the train of accumulated bottles. In this case, the transport jets J in the portion of the conveyor concerned will be temporarily interrupted or at least reduced (by closing the registers 7 controlling this portion of the conveyor).

In accordance with a preferred but not limiting characteristic of the invention, the vertical distance between the guides under the neck 1 and the lower blowing sheath 8 is adjustable. This characteristic advantageously makes it possible to produce a multi-format air conveyor, that is to say a conveyor which can easily be adapted to transport bottles of various shapes and sizes.

In the variant of FIG. 1, this adjustment is obtained by adjusting the position of the guides under the neck 1 in a vertical plane, the blowing sheath 8 being fixed relative to the ground. To this end, the profile 2 supporting the guides under the neck 1 is movable along a vertical axis by being mounted on a plurality of slides 17 which are judiciously distributed over the length of the conveyor and which are vertically movable between two columns 18. Each slide 17 can be moved vertically by means of a jack 19 which is mounted on a frame 20 and whose rod 19 'is rigidly connected by any means suitable for the slide 17. The jacks 19, the frame 20, the columns 18, the lateral blowing sheaths 3, the lower blowing sheath 8, the lower longitudinal guide 13 and the lateral guides 16 form an assembly rigid and fixed to the ground. Thus, the adjustment in the vertical position of the guides under the neck 1 by means of the jacks 19 makes it possible to adjust the distance separating the guides under the neck 1 not only from the lower blowing sheath 8, but also from the lower longitudinal guide 13 (adjustment of the 'minimum conveying angle A). It is up to the person skilled in the art to adjust on a case-by-case basis the distance separating the guides under neck 1 from the lower blowing sheath 8 and from the lower longitudinal guide 13 so as to obtain optimum conveying of the bottles. In practice, after carrying out tests with different formats of bottles, it was found that for most of the bottles existing on the market, the bottles were transported under optimal conditions by adjusting the minimum conveying angle A between 2 ° and 20 °, and preferably between 5 ° and 10 °, the choice of the angle in this range of values having to be made on a case-by-case basis empirically by a person skilled in the art for a given type of bottles. These values of minimum conveying angle A are, however, given purely by way of indication, and are not limitative of the invention, the invention being able to be implemented with minimum conveying angles A outside of the above-mentioned range of values. .

In the variant of FIGS. 1 and 2, the transport under the action of air jets J of the bottles along the conveyor is not carried out by means of transport air jets generated above the flange of the bottles, but is carried out exclusively by a side blowing by means of transport air jets J which are generated below the guides under the neck 1. This advantageously limits the risks that the air may be in direct contact with the neck of the bottles and / or can penetrate inside the bottles B and come to contaminate them.

It should be emphasized that prior to the invention, it was already known to transport bottles suspended under the action of air jets generated below the point of lift of the bottles and to obtain the aforementioned advantage relating to the non-contamination of the bottles. However, to date this lower blowing has been carried out to the detriment of the proper conveying of the bottles, the latter tending under the action of the transport air jets to oscillate forward at a greater angle compared to blowing carried out exclusively above the collar. Thanks to the implementation mainly of reverse air jets R, and moreover in the particular variant of Figures 1 and 2 of the lower longitudinal guide 13, this drawback is now eliminated.

There is shown in Figures 3 and 4 another alternative embodiment of a conveyor according to the invention.

A first difference with the variant of FIGS. 1 and 2 resides in the orientation of the blowing slots 12 'of the lower blowing sheath 8, which are oriented opposite the slots 12 of the variant of FIG. 1, c' that is to say the direction of transport (SDT) of the bottles B. Thus, lower air jets J 'are formed which always have a vertical component (Vz) oriented upwards (same effect of lift of the bottles and same advantages arising from this lift only for the variant of FIGS. 1 and 2) but this time with a horizontal component (Vh) which is oriented in the direction of transport of the bottles. These lower air jets J ′ consequently participate by their horizontal component (Vh) in the propulsion of the bottles in the direction of transport (SDT).

A second difference with the variant of FIGS. 1 and 2 lies in the implementation of two additional lateral blowing ducts 3 ′ which are arranged on either side of the path of the bottles, and which are designed to generate jets of reverse air R 'towards the bottles. To this end, each blowing duct 3 'has at its face 3'a oriented towards the bottles a plurality of blowing slots 4 ′, which are oriented opposite the blowing slots 4 of the sheath 3.

In the particular variant illustrated in FIG. 3, the lateral blowing ducts 3 and 3 ′ are produced by means of the same box 3 "separated into two upper and lower compartments by a partition plate 21, the upper compartment forming the sheath supply 3 for the formation of the transport jets J and the lower box forming the supply duct 3 'for the formation of the reverse air jets R'. In another variant, the positions of the supply ducts 3 and 3 'could be inverted (the duct 3 'being positioned above and no longer below the duct 3) Also, the supply ducts 3 and 3' could be constituted by two separate boxes, which can be supplied with air under pressure of independently or not.

In the variant of FIG. 3, the supply of pressurized air to the blowing duct 3 is carried out by means of the duct 3 ′ and an inlet opening 22 provided in the partition wall 21. Au level with this intake opening 22 is mounted an air distribution slide 23 provided for being actuated between a high position and a low position by a jack 24. In the low position (position of the slide 23 on the right in FIG. 3 ), the slide 23 connects the supply connection 6 to the inlet opening22, isolating the interior of the blowing duct 3 'from the fitting 6, and connecting the interior of the blowing duct 3 with the duct distribution 5, which makes it possible to generate the transport air jets J in the direction of the bottles. Conversely, in the high position, such as in the position of the drawer 23 on the left in FIG. 3, the interior of the blowing duct 3 is isolated from the distribution duct 5, and the blowing duct 3 ′ is supplied with pressurized air, which allows the formation of reverse air jets R 'towards the bottles.

In operation, the drawers 23 on the left and on the right will either be in the high position (generation of reverse air jets R 'on the bottles) to, for example, unlock, or slow down and possibly aeraulically stop the bottles in a given section of the conveyor, either in the low position (generation of transport air jets J towards the bottles) to propel the bottles in the normal transport direction SDT. It is also possible with the conveyor of FIG. 3, to reverse the normal direction of transport of the bottles in the conveyor, the roles of the air jets coming from the blowing ducts 3 and 3 ′ being in this case reversed. The conveyor is thus perfectly reversible from a point of view of the normal direction of transport of the bottles, and this in an easy and rapid manner, without requiring any structural modification of the conveyor.

In the variant of FIG. 3, the blowing ducts 3 and 3 ′ are supplied from the same source of pressurized air. In another variant, these blowing ducts could be provided to be supplied independently from different air sources. In the variant of FIGS. 3 and 4, the lateral transport air jets J apply aeraulic thrust forces to the bottles which make it possible to propel the bottles in a slightly inclined rearward position. The lower air jets J ′ essentially have a lifting effect on the bottles and to a lesser extent participate in the propulsion of the bottles. The lift of the bottles relative to the guides under neck 1 makes it easier to tilt the bottles towards the rear under the action of the lateral transport air jets J. The lower air jets J 'certainly have a tendency, unlike side transport air jets J, to tilt the bottles forward. However, by judiciously adjusting the air power differential between the side transport air jets J and the lower air jets J ', the air power of the side transport air jets J being greater than that of the lower air jets J ', the bottles are conveyed in an inclined rearward position by a conveying angle A'. This angle A 'depends on the power differential between the air jets J and J'. In this case, in a manner comparable to the variant of FIGS. 1 and 2, the implementation of the lower longitudinal guide 13, although preferred, is optional and only constitutes a safety device making it possible to guarantee a minimum conveying angle for bottles. Conversely, on the contrary, for the case where the lateral transport air jets J and the lower air jets J 'are adjusted so that the resulting aeraulic thrust forces applied to the bottles cause them to tilt towards the front relative to the vertical, the implementation of the lower longitudinal guide 13 would in this case be essential to keep the bottles in a tilted back position. The invention is not limited to the implementation of lower air jets R (variant of FIGS. 1 and 2) or J ′ (variant of FIGS. 3 and 4), but more generally extends to any conveyor in which the air jets generated make it possible to maintain the transported articles in an inclined rearward position. In another alternative embodiment (not shown), it is possible in particular to modify the conveyor of FIGS. 1 and 2 by replacing the lower blowing duct 8 with two blowing ducts 3 ′, which would be arranged on either side of the path of the articles and below the air ducts

3, and which would make it possible to generate lateral reverse air jets R ′, simultaneously with the transport air jets J. In this other variant, in a manner comparable to the lower blowing sheath 8 of the variant of the figures 1 and 2, and unlike the variant of FIGS. 3 and

4, the reverse lateral blowing ducts 3 ′ will be provided to be supplied independently with respect to the blowing ducts 3, that is to say so that the air pressure inside the blowing ducts 3 'can be adjusted to a value different from the air pressure inside the supply ducts 3. To do this, the ducts 3' and 3 can for example either be supplied with pressurized air from sources of 'air (fans) different, either be supplied in parallel with pressurized air from the same air source, means for adjusting the air supply flow rate such as, for example, registers being designed to independently adjust the air pressure inside each duct 3 and 3 '. In this variant, the position and the power of the reverse air jets (supply duct 3 ') with respect to the power of the transport air jets (supply duct 3) must be carefully chosen so as to apply to the bottles a couple of forces keeping them in a tilted back position. In this perspective, and unlike the variant of FIGS. 3 and 4, the reverse blowing ducts 3 ′ will preferably be separate and distant from the blowing ducts 3. In the variant of Figures 3 and 4, the lower air jets allow both to ensure the lift of the bottles during transport and in combination with the transport air jets J, to adjust the tilt towards the rear of the bottles by a judicious adjustment of the air power differential between the jets of air J and J '. In the context of the invention, the lower air jets J ′ are not necessarily generated below the articles transported so as to support them. In another variant, these lower air jets J ′ could be lateral transport air jets, oriented towards the front in the direction of transport of the articles, and generally generated at a level situated above below the level of the upper lateral transport air jets J. For this purpose, it will be possible to generate these lower transport air jets, use a lateral supply duct of the same type as the supply duct 3, and positioned at a lower level. It is appropriate for the skilled person to adapt the distance separating the air ducts in height allowing the generation of the upper lateral and J lower transport air jets J ', as well as the aeraulic power differential between these upper J and lower J 'air jets, so as to obtain the desired inclination towards the rear of the articles being transported. In the particular variant embodiments of FIGS. 1 to 4, the side blowing on the bottles is carried out each time by means of two blowing ducts arranged on either side of the cylinder path (blowing ducts 3 for the transport air jets J, and blowing ducts 4 for the reverse air jets R '). This is not limitative of the invention. In another alternative embodiment, it is possible to no longer carry out a bilateral blowing, but to carry out a monolateral blowing by means of a single blowing sheath. This principle of one-sided blowing can be applied both to the lateral air jets of forward-facing transport in the direction of transport of the bottles, and to the reverse air jets R 'oriented in the opposite direction to the direction of transportation of items.

An air conveyor can be produced over its entire length by using only the solution of FIGS. 1 and 2 or the solution of FIGS. 3 and 4. It is also possible to implement these solutions only on a limited portion of the conveyor, the rest of the conveyor being of conventional embodiment and known prior to the invention. Also, the conveying solution of the variant of Figures 1 and 2, and the conveyor solution of the variant of Figures 3 and 4 may advantageously be implemented together on the same conveyor, on different sections of this conveyor. In particular, it may be advantageous to produce for example a conveyor which over its entire length, with the exception of its uphill portions, conforms to the variant of FIGS. 1 and 2, and for the uphill portions of the conveyor put implementing the variant of FIGS. 3 and 4 (that is to say the formation of lower air jets J 'participating in the propulsion of the articles in the direction of transport SDT). Also in the lowering portions of a conveyor, it is preferable and advantageous to use the variant of FIGS. 1 and 2 (formation of reverse lower air jets R) rather than the solution of FIGS. 3 and 4.

Claims

1. Method for transporting articles (B) suspended between two guide rails (1), under the action of air jets and in a given direction of transport (SDT), characterized in that one applies to the articles of the air thrust forces which allow them to tilt backwards with respect to the direction of transport (SDT).

2. Method according to claim 1 characterized in that to maintain the articles in an inclined rearward position during transport, it generates in the direction of the articles and over the entire length of the conveyor reverse air jets which are oriented in the opposite direction to the direction of transport (SDT) of the articles.

3. Method according to claim 1 characterized in that to maintain the articles in an inclined rearward position during transport, it generates in the direction of the articles of the upper transport air jets (J) and lower (J ') which are oriented forward in the direction of transport (SDT) of the articles, the lower air jets (J ') being generated at a level below the level of the upper air jets (J).

4. Method according to one of claims 1 to 3 characterized in that the articles are transported by being inclined backwards by an angle of at least 2 ° and preferably at least 5 °.

5. Method according to one of claims 1 to 4 characterized in that the articles are supported by a plurality of lower air jets (R; J ') which are generated below the path of the articles and which are directed upwards.

6. Method according to claim 5 characterized in that the lower air jets (R) are also oriented towards the rear in the direction opposite to the direction of transport (SDT) of the articles.

7. Air conveyor for transporting articles (B), comprising two guide rails (1) on which the articles can be suspended, and aeraulic means making it possible to propel, under the action of air jets, the articles between the two guide rails and in a given direction of transport (SDT), characterized in that the aeraulic means are designed to apply to the articles aeraulic thrust forces which make it possible to keep them in a tilted back position in relation to their direction of transport (SDT)

8. Conveyor according to claim 7 characterized in that the aeraulic means comprise a blowing sheath (8) which is mounted in the lower part of the conveyor below the path of the articles, which is intended to be supplied with air under pressure, and which comprises an upper face (8a) in which are formed a plurality of slots or openings (12; 12 ') distributed over the length of the blowing duct, and allowing the exhaust of the pressurized air inside the sheath in the form of a plurality of air jets oriented upwards.

9. Conveyor according to claim 8 characterized in that at least a portion of the blowing slots or openings (12) of the lower blowing sheath (8) allow the escape of pressurized air inside the duct in the form of a plurality of reverse air jets (R) which are oriented not only upwards but also in the opposite direction to the direction of transport (SDT) of the articles, and which therefore make it possible to apply on the articles an air pressure force having the effect of tilting the articles backwards.

10. Conveyor according to claim 8 or 9 characterized in that at least a portion of the blowing slots or openings (12 ') of the lower blowing sheath (8) allow the escape of pressurized air to the interior of the sheath in the form of a plurality of air jets (J ') oriented in the direction of transport (SDT) of the articles.

11. Conveyor according to any one of claims 7 to 10 characterized in that it comprises a lower longitudinal guide (13) which comprises two longitudinal guide walls (15) opposite, which is positioned or is able to be positioned with respect to the guide rails (1) of the articles so that an article suspended on the guide rails (1) comes into contact at its base with the two guide walls in being kept inclined with respect to the vertical and rearward with respect to the direction of transport (SDT) at a minimum conveying angle (A).

12. Conveyor according to claim 1 1 characterized in that each guide wall (15) of the lower longitudinal guide (13) forms an inclined plane (PP) relative to the vertical, the planes (PP) formed by the two walls of guide converging towards each other downwards.

13. Conveyor according to claim 12 characterized in that the inclined planes (PP) formed by the two guide walls of the longitudinal guide (13) are inclined relative to the vertical by the same angle (E).

14. Conveyor according to claim 13 characterized in that the angle (E) is substantially 45 °.

15. Conveyor according to any one of claims 1 1 to 14 characterized in that the position of the lower longitudinal guide (13) relative to the guides under the neck (1) is such that the minimum conveying angle (A) of the articles is between 2 ° and 20 °, and preferably between 5 ° and 10 °.

16. Conveyor according to any one of claims 8 to 15 characterized in that it is equipped with means for adjusting the vertical distance separating on the one hand the guides under the neck (1) and on the other hand the blowing sheath lower (8) and if necessary the lower longitudinal guide (13).

17. Conveyor according to any one of claims 7 to 16 characterized in that the aeraulic means are designed to generate air jets exclusively below the guide rails (1).

18. Conveyor according to claim 17 characterized in that for the formation of transport air jets the aeraulic means comprise at least one blowing duct (3) which is designed to be supplied with air under pressure, and which comprises a face (3a) oriented towards the articles in which slots are provided or blowing openings (4).

19. Conveyor according to any one of claims 7 to 18 characterized in that the aeraulic means are designed to generate on the articles of reverse air jets (R ') oriented in the opposite direction to the direction of transport (SDT) of items.

20. Conveyor according to claim 19 characterized in that the reverse air jets (R ') are lateral air jets generated below the guide rails (1).

21. Conveyor according to claim 20 characterized in that for the formation of reverse lateral air jets (R '), the aeraulic means comprise at least one blowing duct (3') which is intended to be supplied with pressurized air , and which has a face (3'a) oriented towards the articles in which are provided slots or blowing openings (4 ') for the exhaust of pressurized air inside the sheath (3') in the form of reverse air jets (R ').

22. Conveyor according to claims 18 and 21 characterized in that the blowing ducts (3) and (3 ') are arranged below the guide rails (1), in that each blowing duct (3') for the formation of the reverse air jets on the one hand is arranged above or below, and is preferably distant from, a blowing duct (3) for the formation of the transport air jets, and on the other hand is supplied with pressurized air independently from the blowing duct (s) (3).