WO2007003735A1

WO2007003735A1 - Accumulator table comprising two adjacent conveyor surfaces which are driven in opposing directions

Info

Publication number: WO2007003735A1
Application number: PCT/FR2006/001418
Authority: WO
Inventors: Didier Droesbeke
Original assignee: Netra Systems
Priority date: 2005-06-28
Filing date: 2006-06-22
Publication date: 2007-01-11
Also published as: FR2887533B1; FR2887533A1; EP2107992A1

Abstract

The invention relates to an accumulator table (1) comprising: first (110) and second (120) adjacent conveyor surfaces, first drive means (121; 131) for driving the conveyor surfaces (110; 120) in opposing directions (D1; D2), transfer means (14) which can move in relation to the first and second conveyor surfaces and which are used to divert the articles and to guide same laterally as they are being transferred from one conveyor surface (110) to the other (120), and second drive means (141) for moving the transfer means (14) in the above-mentioned directions (D1; D2). The aforementioned transfer means (14) comprise: a carriage (140) which is positioned above the two conveyor surfaces (110; 120) and which can move and be guided in translation in the directions (D1; D2) in which the first (110) and second (120) conveyor surfaces are moved; and means (142) for the lateral guiding of the articles, which are fixed to the carriage (140) and which extend above the two conveyor surfaces (110, 120). The second drive means (141) comprise a motor (M4) which is installed on board the carriage (140).

Description

ACCUMULATION TABLE HAVING TWO ADJACENT TRANSPORT SURFACES TRAINED IN DIRECTIONS

OPPOSING

Technical area

The present invention relates to the general field of transport of articles placed on transport surfaces, and more particularly in this field the dynamic accumulation of articles. It relates to an improvement made to FIFO accumulation tables (first in / first out) having at least two adjacent transport surfaces, and driven in opposite directions, and movable transfer means for lateral guidance of articles during their transfer between the two transport surfaces. The accumulation table of the invention can be used in any industry where it is useful to control a flow of articles for example between two upstream and downstream installations. It finds for example, but not exclusively, its application to the control of a stream of light articles, such as packages, empty or filled containers, including bottles, boxes, etc.

PRIOR ART It is currently customary to use an accumulation table to manage the flow of articles transported between two upstream and downstream installations (for example in the field of bottling between an upstream bottle production machine and an downstream machine for filling said bottles), and adapting this flow of articles according to operating rates or temporary stops of upstream and downstream installations.

Among the various types of accumulation table known to date, there is a first type of accumulation table, described in particular in international patent applications WO 02/32797 and WO 01/09015, and in the US patent application. US 2003/029409. This type of accumulation table has at least two adjacent transport surfaces driven in opposite directions and movable guide means which allow the articles to be deflected and laterally guided during their transfer between the two transport surfaces.

In this first type of accumulation table, the guide means comprise a lateral guide element or equivalent, which is disposed above the two transport surfaces, and which allows to block and guide laterally transported articles by deviating their trajectory to transfer them from one transport surface to another. This lateral guide element may consist in its simplest variant embodiment in a wall or passive baffle. In a more sophisticated embodiment, this lateral guide element may also comprise an active moving part, for example in the form of a transfer belt for active lateral guidance of the articles.

This lateral guide element is movable in both transport directions of the transport surfaces and its position is automatically adjusted according to the speed differential between the two transport surfaces. The means for adjusting the position of this lateral guide element are designed such that in operation the lateral guide element automatically moves in the driving direction of the fastest conveying surface. When the speeds of the two transport surfaces are identical, this lateral guide element is stationary. In the main examples of embodiment described in the aforementioned international patent applications WO 02/32797 and WO 01/09015, the automatic adjustment of the position of this lateral guide element is obtained by mechanically coupling the movement means of the element of lateral guidance to the motorized drive means of the two transport surfaces.

The aforementioned accumulation tables allow a management of the flow of articles which is FIFO (first in / first out) type. In particular, this type of accumulation table makes it possible to guarantee, generally more than 90%, that the order of the transported articles is preserved, which is very important in all the applications where traceability of the articles must be assured. This first type of accumulation table also has the advantage of being compact because the transport surfaces are adjacent.

In this first type of accumulation table, to obtain a transfer of articles from one transport surface to another, the spacing between the two transport surfaces must be smaller than the dimension of an article, so that that in the course of transfer an article can be supported simultaneously by the two transport surfaces. For this transfer to be reliable and effective, it is preferable to reduce to a minimum the spacing between the two transport surfaces (1 strain ^AD). Furthermore, in this first type of accumulation table, the lateral guide element, which allows the guidance of the articles from one transport surface to the other, undergoes during operation significant mechanical forces under the pressure of the articles, particularly when articles accumulation phases ^(2nd constraint). In the above-mentioned US patent application US 2003/0209409, two variants are proposed, which are respectively illustrated in FIGS. 7 and 8, and which are satisfactory with regard to the first aforementioned constraint, since they make it possible to reduce to a minimum very low value the spacing between the two transport surfaces. The technical solution adopted in these two embodiments consists in fixing the lateral guide element on at least one lateral transport belt, which extends on one side of one of the transport surfaces, opposite the other transport surface.

These two embodiments are however not satisfactory with regard to the second aforementioned constraint (significant pressures experienced by the lateral guide element). Indeed, the conveyor belt or belts of this lateral guide element are characterized by a large operating clearance, and in case of significant pressure exerted by the articles on this lateral guide element, they do not allow to guarantee a sufficient mechanical strength of this lateral guide element. In particular, in the variant of Figure 7 of the aforementioned US patent application US 2003/0209409, the cantilever mounting of the lateral guide member considerably increases the mechanical strength problems of this guide, and requires in practice to limit the width of the

5 accumulation table, to avoid excessive pushes on this guide.

Also, in the variant of Figure 8 of the aforementioned US patent application US 2003/0209409, there is a risk of creation over time of a mechanical shift between the two conveyor belts on which the guide element is fixed. lateral of the articles, in particular because of the elongation over time of these belts. This mechanical shift is detrimental to the proper functioning of the accumulation table.

These two variants of FIGS. 7 and 8 also have the disadvantage of making the transported articles less easily accessible for an operator.

A second type of accumulation table is also known, employing two rectilinear and spaced main conveyor belts, and an intermediate curved conveyor belt interposed between the two main conveyor belts. This second type of accumulation table is described for example in the US patent application

US 20003/0155212 and in the French patent application FR 2 766 803.

Since this type of accumulation table does not include a lateral guide element for the articles, it makes it possible to avoid the effects of the pressure of the articles, in particular in the accumulation phase, which are inherent in the aforementioned first type of table. accumulation. However, this second type

. The accumulation table is less compact than the accumulation tables of the first type mentioned above. In addition and above all, the intermediate curved conveyor belt, which is used for the transfer of articles from one main conveyor belt to another, is very complex to implement and implement, which disadvantageously , makes this second type of accumulation table more complex and more expensive to manufacture than the tables accumulation of the aforementioned first type.

Objective of the invention

The present invention aims at providing a new article accumulation table which is of the aforementioned first type (adjacent conveying surfaces driven in opposite directions, in combination with means for lateral guidance of the articles during their transfer from a transport surface to the other, which lateral guide means are movable in the two directions of advancement of the adjacent transport surfaces), and which makes it possible to respond simultaneously satisfactorily to the two aforementioned constraints inherent to this type of table. accumulation: obtaining a small gap between the two adjacent transport surfaces; realization of lateral guide means characterized by a very good mechanical resistance to pressure, which contributes to improved reliability and improved strength of the accumulation table.

Summary of the invention

This objective is achieved by the accumulation table defined in claim 1.

In the accumulation table of the invention, the lateral guide means of the articles being subject to a carriage which is positioned and movable above the two transport surfaces, the spacing between the two adjacent transport surfaces can be very small, and the guide means are more robust than the aforementioned variants with conveyor belt (s) described in the aforementioned US patent application US 2003/0209409 (Figures 7 and 8).

Also, the trolley of the accumulation table of the invention does not reduce accessibility to items for an operator, compared to the aforementioned variants with conveyor belt (s) described in the aforementioned US patent application US 2003/0209409. Advantageously, with the accumulation table of the invention, when a blockage of articles occurs during transfer or when a that excessive pressure is exerted by the articles carried on the lateral guide means, it is possible to back the motorized carriage relative to the blocking or overpressure point, without affecting the speed differential between the two transport surfaces . Thus, in case of blockage or excessive pressure, it is not necessary to intervene manually by removing one or more articles from the flow of articles accumulated on the table.

More particularly, the accumulation table of the invention comprises the additional and optional features of the dependent claims 2 to 13, said characteristics being able to be taken separately or, if necessary, in combination with each other.

According to another aspect, another object of the invention is an accumulation table comprising: at least a first and a second adjacent transport surface,

first drive means for driving said transport surfaces in opposite directions (D1; D2),

transfer means which are movable relative to the first and second transport surfaces, and whose function is to deflect and guide the articles laterally during their transfer from one transport surface to the other, second means for drive for moving said transfer means in directions (D1; D2) for moving the transport surfaces;

means for detecting the pressure exerted by the articles on the transfer means, electronic control means which are designed to drive the motor of the second drive means as a function of the pressure detected by the detection means.

Another subject of the invention is a method for controlling a flow of articles by means of an accumulation table as defined above.

Preferably, during the implementation of this method, the pressure exerted by the articles on the transfer means of the accumulation table is automatically detected, and when excessive pressure is detected, the transfer means or the displacement of the transfer means is stopped in order to reduce said pressure.

DESCRIPTION OF THE FIGURES Other features and advantages of the invention will appear more clearly on reading the detailed description below of several variants of an accumulation table of the invention. This detailed description is given by way of nonlimiting and non-exhaustive example of the invention, and with reference to the appended drawings in which:

FIG. 1 is a view from above of a first variant embodiment of an accumulation table of the invention

FIG. 2 is a side view of the accumulation table of FIG. 1; FIG. 3 is a rear view of the accumulation table of FIG. 1;

FIG. 4 is a detailed view of the motorized drive means of the transfer means of the accumulation table of FIG. 1;

FIG. 5 is a schematic representation of a second alternative embodiment of the table of FIG. 1, also showing the various motors and sensors used,

FIG. 6 is a schematic representation of the accumulation table of FIG. 5, the transfer means being in an intermediate position; FIG. 7 is a block diagram of the electronic control means of the motor used for the displacement of the means of transfer, and

- Figure 8 a schematic representation of a third embodiment of an accumulation table of the invention.

DETAILED DESCRIPTION FIGS. 1 to 4 show a first variant embodiment of an accumulation table 1 of the invention that makes it possible to dynamically control a stream of articles conveyed between an upstream zone Z1 and a downstream zone Z2.

The accumulation table 1 comprises four mechanical conveyors 10, 11, 12, 13 supported in height relative to the ground by a carrier frame B '. The conveyor 11 comprises a conveyor belt 110 forming a first main conveying surface, and motorized drive means 111 comprising a motor or gear motor M2, and allowing the driving of this transport surface 110 in a first transport direction D1

The conveyor 12 comprises a conveyor belt 120 forming a second main conveying surface which extends parallel and which is adjacent to the first conveying surface 110. The spacing between the two transport surfaces 110 and 120 is in a manner general, less than the size of an article, such that an article being transferred from one transport surface 110 to the other 120 is simultaneously supported by the two transport surfaces. Preferably, this spacing between the two transport surfaces 110 and 120 is very small, or even zero, the two transport surfaces 110, 120 can be in contact or almost in contact with each other along their selvedge longitudinal.

The conveyor 12 also comprises motorized drive means 121, comprising a motor or gear motor M3, and allowing the driving of this transport surface 120 in a second transport direction D2 opposite to the first transport direction D1. The conveyor 10 fills the input interface function. It comprises a transport surface 100 juxtaposed and parallel to the surface of transport 110 and motorized drive means 101, comprising a motor or gear motor M1, and allowing the driving of this transport surface 100 in the same direction (arrow E) that D1 of the transport surface 110. Above and straddling the two transport surfaces 100 and 110 are mounted two substantially parallel fixed guides G and delimiting an entry guide corridor for the articles.

Conveyor 13 performs the function of output interface. It comprises a transport surface 130, which in the example of FIG. 1 is adjacent and extends perpendicular to the transport surface 120, and motorized drive means 131, comprising a motor or gear motor M5 (not visible on the 1), and allowing the driving of this transport surface 130 in the direction of exit S perpendicular to the direction D2. Above the transport surface 120 is mounted a fixed guide G 'which enables the articles at the outlet of the conveyor 12 to be deflected towards the output conveyor 13.

In the context of the invention, the technology used to make the conveyor surfaces of the various conveyors is irrelevant. In particular, and in a non-exhaustive manner, a transport surface 100, 110, 120 or 130 may be made by means of a belt or conveyor belt, which preferably forms a slippery surface, and which extends over the entire width of the conveyor, or by means of a plurality of parallel conveyor belts or chains. For the same accumulation table, the conveyors 10 to 13 may comprise different technology transport surfaces. The accumulation table 1 comprises transfer means 14 whose function is to deflect and guide the articles laterally during their transfer from the first transport surface 110 to the second transport surface 120. These transfer means 14 comprise:

a mobile carriage 140 which is supported on the carrier frame B ', and which can move above the two conveyors 11 and 12 being guided in translation in the two directions D1 and D2 between two extreme positions A and B,

drive means 141 for moving this carriage 140;

a lateral guide element 142, which is mounted on the carriage 140, and which in the particular example illustrated is constituted by a curved guide forming a deflection baffle of the articles and positioned above the two transport surfaces 110 and 120 Referring to Figure 4, the carrier frame B 'has two fixed guide rails 144, and the carriage 140 is supported and guided on these two guide rails 144 by rollers 143. The carriage 140 can thus move on carrier frame B 'by rolling on the two guide rails 144 in the directions D1 or D2.

The drive means 141 of this carriage 140 comprise:

- On each longitudinal side of the frame B ', a rack 141a which is fixed on the carrier frame B' and which extends substantially over the entire travel path of the carriage 140 between the two extreme positions A and B;

in combination with each rack 141a, a driving pinion 141b which is integral with the carriage 140 and which is carried at the end of a transmission shaft 141c, the pinion 141a meshing with said rack 141a,

a motor gearbox (or motor) M4 embedded on the carriage 140,

coupling means 141 d of the output shaft of this gearmotor M4 with the transmission shafts 144. The aforementioned kinematic chain (141a, 141b, 141c, 141d) makes it possible, when the gearmotor M4 rotates in one direction or in the other, the displacement of the carriage 140 relative to the carrier frame B 'in the direction D1 or in the direction D2 between the two extreme positions A and B.

Preferably, the carriage 140 is centered with respect to the two guide rails 144 of the carrier frame B ', and is also centered with respect to the two racks 141a. Also, the M4 engine on the carriage 140 is centered between the two racks 141a.

Referring to Figure 3, the carriage 140 is not positioned in the immediate vicinity of the two transport surfaces 110 and 120, but is advantageously raised relative to the first 110 and second 120 transport surfaces. This feature facilitates access to these two transport surfaces 110, 120. It also facilitates the cleaning or lubrication of the transport surfaces 110 and 120, and reduce the risk of contact of the M4 engine with the products of cleaning or lubrication. FIGS. 5 and 6 show diagrammatically an accumulation table of the invention similar to that of FIGS. 1 to 4, the only two differences being the orientation of the surface 130 of the exit conveyor 13 relative to at the conveying surface 120, and the curved shape of the lateral guide 142 for the transfer of articles. With reference to FIG. 5, the guide 142 is equipped with two pressure sensors CP1 and CP2 which make it possible to detect the pressure exerted on the guide 142 by the articles. Preferably at least one pressure sensor is provided above each main transport surface 110 and 120 as illustrated in the example of FIG. 5. Also, the accumulation table is equipped with two end-of-travel sensors. Fdc1 and Fdc2, for detecting respectively the two extreme positions A and B above the guide 142. In Figure 5, the guide 142 is in the extreme upstream position A.

The motor M4 of the carriage 140 is controlled by electronic control means of which an example of a block diagram is given in FIG.

These electronic control means comprise a variator VAR which drives in a manner known per se the motor or gear motor M4 of the carriage 140 by means of a control signal S1. This variator VAR is controlled (signal S9) by a programmed control unit, which is for example made by means of a PLC industrial program controller, and which allows to run a trolley management program 140 (and its embedded guide 142) stored in a memory.

This programmed control unit (PLC) receives as input several coding signals S2 to S8:

the signal S2 is delivered by an encoder (Cod1) mounted for example on the output shaft of the gearmotor M2 and supplies the control automation (PLC) with information making it possible to characterize the instantaneous speed of displacement (V1) of the first transport surface 110,

the signal S3 is delivered by an encoder (Cod2) mounted for example on the output shaft of the geared motor M3 and supplies the control automation (PLC) with information making it possible to characterize the instantaneous speed of displacement (V2) of the second transport surface 120,

the signal S4 is delivered by an encoder (Cod3) mounted for example on the output shaft of the geared motor M4 and provides the control automation (PLC) with information making it possible to characterize the instantaneous position of the carriage 140, - the signals S5 and S6 are presence detection signals of the carriage 140, and are respectively delivered by the end-of-stroke sensors Fdc1 and Fdc2,

the signals S7 and S8 are pressure measurement signals delivered by the pressure sensors CP1 and CP2, and provide the control automation (PLC) with information making it possible to characterize the instantaneous pressure exerted by the articles on the guide .

The coders Cod1 and Cod2 are used to detect the actual speeds of displacement (V1; V2) of the transport surfaces 110 and 120. These detection means Cod1 and Cod2 are, however, optional and not necessary for carrying out the invention. In particular, in another variant embodiment, one can remove these sensors Cod1 and Cod2 and replace them for example by any means providing the control automation (API) an indication of these speeds of movement. For example, the motors M2 and M3 are in a manner known per se controlled by variable speed drives, which make it possible to adjust the speed of each motor M2, M3 and which are controlled by means of a control signal whose frequency is characteristic the speed of the motor associated with the drive; it is conceivable in this case that the control automatism

(API) is informed of the moving speeds (V1 and V2) of the transport surfaces 110 and 120, knowing the frequencies of the control signals applied to the variable speed drives associated respectively with the two motor M2 and M3.

The operation of the accumulation table will now be detailed with reference to FIGS. 5 and 6. Normal operation without incident

The programmable logic controller PLC executes a program for managing the position of the guide 142 embedded on the carriage 140.

When this program is executed, in normal operating mode, the programmable logic controller PLC controls the speed controller VAR according to the measured speeds V1 and V2 (signals S2 and S3) of the transport surfaces 110 and 120.

More particularly, the speed of the motor M4 driving the carriage

140 is controlled so that the speed V of carriage movement is given by the following relation: (1) V = (V1 -V2) / 2

V2 being the speed of displacement of the transport surface 120 in the direction D2,

V1 being the speed of displacement of the transport surface 110 in the direction D1. Fill phase

When the speed V1 is greater than the speed V2, the guide 142 is moved automatically at the speed V in the direction D1. This operating mode corresponds to the filling phase of the accumulation table illustrated in FIG. 6. During this phase, the articles 15 which are fed at the entrance of the transport surface 110 by the input conveyor 10 accumulate on the two transport surfaces 110 and 120, the guide 142 retreating towards the extreme downstream position B at the speed V. Drain phase

When the speed V2 is greater than the speed V1, the guide 142 is automatically moved at the speed V in the direction D2, which corresponds to the emptying phase of the accumulation table. During this phase, the articles 15 that have accumulated on the two transport surfaces 110 and 120 are progressively evacuated by the second transport surface 120. At the same time, the guide 142 advances toward the extreme upstream position A to the speed V. Transfer phase

When the speeds V1 and V2 are equal, the guide 142 is stationary (V = 0). The articles 15 pass through the accumulation table 1. The guide 142 can be immobilized at any position between the two extreme positions A and B.

The velocity relationship (1) above is given as a preferred example, but is not limiting of the invention.

Also, the program for managing the position of the guide 142 executed by the programmable logic controller API can be designed to select different preprogrammed velocity relationships, [V = f (V1, V2)], the selection being made depending in particular on the type of items transported and / or the operating phase of the table (filling, transfer or emptying).

In particular, certain types of articles require a specific conveying speed during the filling or emptying phases. Thanks to the implementation according to the invention of a mobile guide 142 independent whose movement can be controlled independently of the differential between the speeds V1 and V2 of the main transport surfaces 110 and 120, one can control the speed of movement of the guide so as to adapt to this specific conveying speed during the phase of filling or emptying phase.

Operation with a truck detected at the end of travel When the programmable logic controller PLC detects that the truck is in one of the extreme positions A or B, thanks to the signals S5 and S6 delivered by the limit switches Fdc1 and Fdc2, stops the motor M4 (V = O) in the two following cases:

- V1> V2 (carriage 140 moving in the direction D1) and the sensor Fdc2 detects the presence of the carriage 140. The guide 142 is stopped in its downstream extreme position B. The accumulation table 1 is configured with its maximum capacity d accumulation of items. - V2> V1 (carriage 140 moving in the direction D2) and the sensor Fdc2 detects the presence of the carriage 140. The guide 142 is stopped in its upstream end position A (position of Figure 5). The accumulation table 1 is configured with its minimum capacity of accumulation of articles. Operation with incident (overpressure on the guide 142 or debourraqe) Overpressure on the guide 142

During operation, the pressure exerted by the articles 15 on the guide 142 is preferably constantly controlled by the industrial programmable logic controller PLC, by means of the signals S7 and S8 delivered by the pressure sensors CP 1 and CP 2, in order to detect any excessive pressure (overpressure) exerted by the articles on the guide 142. For example, the pressures measured by the sensors CP1 and CP2 are compared by the PLC with at least a predetermined pressure threshold. This pressure threshold is for example an operating parameter of the program executed by the PLC, and is preferably adjustable. An overpressure on the guide 142 can be in practice caused by several situations:

When the travel speeds for the input transport surface 100 and the first main transport surface 110 are poorly adjusted (for example when the displacement speed of the input transport surface 100 is greater than the traveling speed of the first main transport surface 110).

- When the travel speeds for the output transport surface 130 and the second main transport surface 120 are poorly adjusted (for example, when the displacement speed of the output transport surface 130 is less than the travel speed of the second main transport surface 120).

- When one or more items are accidentally locked in position in the transfer zone of the accumulation table and prevent the correct operation of the accumulation table

(whatever the operating / filling phase, transfer or emptying).

When the PLC controller detects excessive pressure on the guide 142, two situations may arise: the accumulation table is transfer phase or in the filling phase (V1 ≥V2); in this case, the PLC PLC controls the variator VAR so as to move the guide 142 in the direction D1 at a predetermined speed V (and for example constant) independent of the differential speed V1 and V2 so as to back the guide 142 in the direction D1 until the pressure measured by the pressure sensors CP1 and CP2 becomes acceptable again (below the predetermined pressure threshold).

- The accumulation table is emptying phase (V2>V1); in this case, the PLC PLC controls the VAR in order to stop the movement of the guide 142 until the pressure measured by the pressure sensors CP1 and CP2 becomes acceptable (in below the predetermined pressure threshold).

This advantageously results in automatic operation of the table without excessive pressure on the guide 142.

Also, when the overpressure is due to an article accidentally locked in position, the recoil of the guide 142 in most cases allows to unblock said article, without manual intervention. Manual debauchery

When a malfunction requires manual intervention débourrage, one can also manually control the recoil of the guide 142 in the direction D1 in order to decompress the articles locked in position on the accumulation table and facilitate manual unclogging operations.

The invention is not limited to the preferred embodiment which has just been described with reference to the appended figures. In particular, and in a non-exhaustive manner, the guide 142 could be replaced by any equivalent means fulfilling the same deflection and lateral guiding function of the articles of the first main transport surface 110 towards the second transport surface 120 in the opposite direction of travel. . For example, the guide 142 could be replaced by an active lateral guide comprising a belt or the equivalent making it possible to exert on the articles a positive transfer action such as, for example, the guide with transfer belt of the accumulation table of FIGS. to 3 of the international patent application WO 02/32797. Also the orientation of the input conveyors 10 and output 13 is of no importance for the invention and mainly depends on the implementation constraints of the article conveying line. As a further example, there is shown in Figure 8 another alternative embodiment of an accumulation table according to the invention, wherein the input conveyor 10 is oriented perpendicular to the directions D1 and D2 displacement transport surfaces main 110 and 120.

Claims

An accumulation table (1) having at least a first (110) and a second (120) adjacent conveying surface, first drive means (121, 131) for driving said transport surfaces (110; 120) in opposite directions (D1;

D2), transfer means (14), which are movable with respect to the first and second conveying surfaces, and whose function is to deflect and guide the articles laterally during their transfer from a transport surface (110) to the other (120), and second drive means (141) for moving said transfer means (14) in directions (D1; D2) for moving the transport surfaces (110; 120), characterized in that the transfer means (14) comprise a carriage (140) which is positioned above the two transport surfaces (110, 120) and which is movable and guided in translation in the directions (D1; D2) of movement of the first (110) and second (120) conveying surfaces, and means (142) for lateral guidance of articles which are secured to the carriage (140) and which extend above the two transport surfaces (110, 120), and in that the second drive means (141) comprise a motor (M4) embedded on the carriage (140).

2. Accumulation table according to claim 1, characterized in that the motor (M4) of the second drive means (141) allows, if necessary, to move the transfer means (14) independently of the speed differential between the two transport surfaces (110; 120).

3. Accumulation table according to one of claims 1 or 2, characterized in that the second drive means (141) comprise at least one fixed rack (141a) meshing with a motor pinion (141b) coupled to the motor ( M4).

4. Accumulation table according to claim 3, characterized in that that the second drive means (141) comprise at least two parallel fixed racks (141a) meshing respectively with two pinions (141b) coupled to the motor (M4).

5. Accumulation table according to claim 4, characterized in that the motor (M4) is centered between the two racks (141a).

6. Accumulation table according to one of claims 1 to 5, characterized in that the carriage (140) is supported by two guide rails (144) and is centered with respect to the two guide rails (144).

Storage table according to one of claims 1 to 6, characterized in that the carriage (140) is raised relative to the first (110) and second (120) transport surfaces, so as to facilitate the access to these two transport surfaces.

8. Accumulation table according to one of claims 1 to 7, characterized in that it comprises first detection means (Cod1; Cod2) for measuring the speeds (V1; V2) of displacement of the first (110) and second (120) transport surfaces.

9. Accumulation table according to one of claims 1 to 8, characterized in that it comprises electronic control means (API, VAR) which are designed to control the motor (M4) of the second drive means in function of the speed differential of the first (110) and second (120) transport surfaces.

10. Accumulation table according to one of claims 1 to 9, characterized in that it comprises second detecting means (CP1, CP2) of the pressure exerted by the articles on the transfer means (14).

11. Accumulation table according to claim 10, characterized in that it comprises electronic control means (API, VAR) which are designed to control the motor (M4) of the second drive means as a function of the detected pressure. by the second detection means (CP1, CP2).

12. Accumulation table according to claim 11, characterized in that the electronic control means (API, VAR) are designed to drive the motor (M4) of the second drive means so as to maintain the pressure exerted on the means transfer

(14) below a predefined pressure threshold.

13. accumulation table according to one of claims 9 or 11, characterized in that the electronic control means comprise a programmed control unit (API) which controls the motor (M4), and a program for managing the movement of transfer means (14) which is stored in memory and is executable by said programmed control unit (API).

14. A method of controlling a flow of articles (15), characterized in that an accumulation table according to any one of claims 1 to 13 is used.

15. The control method as claimed in claim 14, characterized in that the pressure exerted by the articles is automatically detected.

(15) on the transfer means (14) of the accumulation table, and when excessive pressure is detected, the transfer means (14) are moved back or the transfer means are stopped

(14) to decrease said pressure.