FR3000950A1 - METHOD AND DEVICE FOR FEEDING LONG AND FLEXIBLE FOOD PRODUCTS A PACKAGING MACHINE - Google Patents

Abstract

It involves feeding, in products such as sausages, a packaging machine. For this: - the food products (1) are moved by one or more upstream conveyors (191, 193) on at least one of which is created a buffer zone (10) for accumulation of food products, - then the accumulated food products are moved by a downstream conveyor (13) provided with housings (13a) for individual or grouped reception of the food products, for feeding the packaging machine, with the particularity that: - the buffer zone (10) is created on a surface of the Upstream conveyors without accommodation for individual or group reception of food products.

Description

The invention relates to a method for feeding a packaging machine into long, flexible and naturally curable food products. Long, flexible and naturally curable food products are defined as any product of this nature that, for example, an outer envelope can cause, under constraint imposed by it, to change shape. This concerns sausages, sausages and other food products in pieces placed in a casing. One objective is to automatically package fresh sausages in natural gut. The production of fresh sausages in natural gut is not a continuous but discontinuous production, due to non-compliant sausages that are not ejected, or the change of casing which generates a slight hole in the production. The regularity of production of food products concerned is often very variable depending on the quality of the envelope (gut in particular) or the dexterity of the operator. This is a disadvantage. One solution chosen to provide a solution to this is to create an accumulation, as described in the patent FR2951444; but this technical solution requires a relatively complex mechanics which imposes an additional cost of the equipment (ancillary systems, adjustments ...). Another solution proposed here is to provide that: the food products are placed on and moved by one or more upstream conveyors on which, or on at least one of which, a buffer zone of accumulation of food products is created, - Then the accumulated food products from the upstream conveyor or conveyors are placed on and moved by a downstream conveyor provided with individual receiving housing or grouped food products, to feed the packaging machine, - and the buffer zone is created: 0 on a surface of the upstream conveyor or conveyors without receiving individual or group receiving food products (hence the name of smooth belt conveyor below), and / or a portion of soft strand on at least one of conveyors, by varying the tension of the belt with which the conveyor is equipped, and / or the length of this belt. To facilitate flow management (several thousand food products per hour), it is recommended to proceed as follows: - several upstream conveyors are used comprising a first conveyor and then at least a second conveyor, placed after one of the other or each of the other, each without receiving individual or grouped reception of food products, and - the food products from the first conveyor are then placed on and moved by the second or second conveyors where the buffer zone is created. accumulation of food products. Again for rapid management of these flows and avoid constraints on food products that may alter their shape (including excessive bending, it is recommended to arrange the second conveyors or: - in alignment with each other, if there are several, and - transversely to the first conveyor As an alternative or complementary, the following is recommended: the second conveyor (s) is set in motion so that the food products move with them in parallel in the direction of elongation of said food products brought on this or these second conveyors and, on the downstream conveyor, the food products are moved perpendicularly to their direction of elongation.The transverse or perpendicular arrangement will facilitate the loading of individual receiving houses or grouped food products.

To promote the most regular and high possible supply of packaging machine located at the end of this supply chain, it is advisable to ensure filling of the receiving housing of the downstream conveyor: - either total, - or in batches. A very high rate, more than a dozen thousand food products per hour, can typically not yet allow to manage sufficiently well the most regular and high possible diet of the packaging machine. In order to create the buffer zone and adapt the food supply of the downstream conveyor, it is advisable to: - either collect information concerning the circulation of the food products on the upper end of at least some of the upstream conveyors and adapt according to the sensed information, the velocity or the relative velocities of the upstream conveyor (s) and / or the downstream conveyor, - either: to use several second conveyors aligned in the continuity of each other, to interpose on all or part of of these second conveyors a door that is opened and closed, to collect information concerning the circulation of said food products on the upper strand of all or part of these second conveyors, * and to adapt according to the information collected openings and door closures. In connection with the foregoing, it is proposed to collect information concerning the running of the upstream conveyor (s), or the food products placed on this or these upstream conveyors, and to adapt the speed of the downstream conveyor (s) according to the information collected. , by a slowdown or a stop, at least momentary, of this or these downstream conveyors. It is further proposed that the aforementioned step of collecting information includes that of sensing a spacing between food products traveling on the conveyor or upstream. At least one camera and / or photoelectric cells coupled to a processing electronics acting on the drive motors of the conveyors would be suitable. To further refine the management of flows and / or the circulation of food products on conveyors, the following is recommended: a) - the downstream conveyor is driven at a constant speed, which may be the same as that of the conveyor (s) ) upstream, except at certain times when said downstream conveyor speed is slowed down, when there is a deficit of food products in the buffer zone, or: b) - several second conveyors aligned after each other are used, - and moving said second conveyors in motion at different relative speeds, or: c) moving the or all or part of the upstream conveyors in motion at speeds that are varied over time; the upstream conveyor, or all or part of the upstream conveyors, at least one door that is closed and opened. To adapt the product flow rate and to completely fill the trays at the exit of the conveyors, this in a single operation (typically by a robotized robotic arm at the end of the last conveyor), it is also proposed to create a portion of soft strand on at least one of the conveyors (preferably the downstream conveyor because the closest to the robot / trays), thereby varying the tension of the conveyor belt and / or the length of the belt.

Concerning the packaging machine and its optimized feeding, it is further recommended: - that the downstream conveyor distributes the food products to a robot manipulator of this machine which will load food products, from this downstream conveyor, trays, and / or - that the first conveyor receives the food products immediately out of the production line. Thus, the chain between production and packaging (here put in trays) will be as short as possible, guaranteeing simplicity, efficiency. Another recommendation is that the feed device of the machine is such that motors act in a different way on one of the conveyors, preferably the downstream one, with a motor at each end so that the one further downstream ensures advance of the strand after at least one product withdrawal from the conveyor and that further upstream ensures the advance after the arrival of at least one of said products on the conveyor. Thus, it will create a portion of soft strand on the conveyor whose flexible strip is flexible. More generally, concerning this feed device, it is advisable that it comprises: a buffer zone for accumulation of said products created by means for regulating the flow rate of the food products circulating on the or at least one of said upstream conveyors and / or by a portion of soft strand on one of the conveyors, which has a flexible moving band.

Preferably it will further comprise means for maintaining said food products along a portion of at least one of the upstream conveyors. Other features and advantages of the invention will appear again or more clearly from the following description of various embodiments, given by way of non-limiting examples, and the accompanying drawings, in which: FIGS. 1 and 2 are diagrams, respectively from above and from the side (according to arrow II), of the claimed device, according to a first embodiment; - Figures 3 and 4 are diagrams, respectively from above and from the side (according to arrow IV), of the claimed device, according to a second embodiment; - Figures 5 and 6 are diagrams, respectively from above and from the side (according to the arrow VI), of the claimed device, according to a third embodiment; and FIGS. 7 and 8 are diagrams, respectively from above and from the side (according to arrow VIII), of the claimed device, according to a fourth embodiment, and FIGS. 9A-14 illustrate fifth (FIGS. 13C) and sixth embodiments (FIG. 14A-14C) as follows: FIGS. 9A, 9C, 9E are views respectively along 9A, 9C and 9E (section), FIGS. 10A, 10C, 10D are views respectively along 10A , 10C and 10D (section), Figs. 14A, 14B, 14C are views respectively along 14A, 14B, 14C and Fig. 15 is the section along XV. In the accompanying drawings, all cases of operation are therefore presented as examples, for sausage packaging 1 where minced meat, mixed with other ingredients, 3, is thus wrapped with a hose 5 (natural or artificial, such as a shell of hardened skin material obtained by dipping the food product into pieces in a coagulation solution, see NL 6909339 or WO 2006/135238). 1ère solution exposed (Figures 1 and 2): After the machine 7 portioning sausages, is received, via a first axial conveyor 9 to band (here endless) smooth 9a, sausages on the smooth band 19a of a second conveyor 19 (here endless) perpendicular to the axis of travel 11 (upstream conveyor) to obtain sausages stored on the conveyor 19 in parallel with each other. This second conveyor 19 advances at the same speed as a downstream conveyor 13 which will recover the sausages so as not to have a hole in the blister strip 13a. The operation of this downstream conveyor 13 is intermittent and it operates only when there is an accumulation of sausages parallel to its inlet.

An automation system will ensure starting or stopping of the blister strip depending on the level of production. As in the other solutions, the smooth-belt conveyors 1.19 are devoid of individual or grouped receiving receptacles for food products, whereas the downstream conveyor 19 is provided with such housings, as illustrated. These housings define, around the endless belt 13a, cells or cradles extending parallel to the common axis of elongation sausages which are arranged parallel to each other on the second and third conveyors 19,13. The straight line of elongation of each of the cells or cradles of the downstream conveyor 13 is parallel to the scroll axis 11. The only three successive conveyors adjacent to each other, two by two, 1,19,13, are here sufficient to obtain this expected flow management via the buffer zone 10.

In conclusion, according to this solution, the buffer zone will be obtained and the supply of food products of the downstream conveyor 13 will be adapted, by drive in motion (here rotation): - the upstream conveyor 19 (or both conveyors 1,19) constant speed, - and the downstream conveyor 13 also at constant speed, except at certain times when this speed is slowed, possibly to choose to cancel (in fact, we will preferably have two speeds: a first constant speed and common conveyors upstream 19 and downstream 13, and cancellation -or very sensitive reduction of the speed of the downstream conveyor 13 'with maintenance of the constant speed of the upstream conveyor 19, this via the information sensors 23,25 (associated well electronic means for processing the sensed information, so that the velocities and / or openings / closures of the door 15 are operational, as explained below, the photocells 25 and / or the a camera 23, located (s) facing the band 19a (for example above), upstream of the zone 10 (and therefore the downstream conveyor 13) can usefully intervene in the management of the filling zone 13a and / or that of accumulation 10. 2nd solution exposed (Figures 3 and 4): This is again to receive the sausage 1 by a series of carpets, or second conveyors 19, each perpendicular to the first conveyor 9 and which receive the sausages parallel to their axis to the common axis elongation.

But the second conveyors 19 have a sinusoidal or differential speed variation (s) operation which ensures a setting of the sausages to enter the cellular strip 13. During a hole, upstream, in the production, here via the machine 7, the blister strip 13 can stop to wait for a new train of sausages. In fact, the solution chosen here consists in: - using several second conveyors, here 19a, 19b, 19c, aligned after each other and driving them in motion at different relative speeds, and preferably in addition to to slow down, or even to stop, the downstream conveyor 13 with a cellular band 13a. As illustrated, the photocells 25 and / or the camera 23 are preferably also used in this case to manage the accumulation zone 10. 3rd solution (FIGS. 5 and 6): A carpet, or second conveyor, 19, perpendicular to the production line (which opens as previously on the first axial conveyor 9 smooth band 9a) receives the sausages in parallel (la). A system, here a door 15, allows the grouping of a batch 10 of products 1 which will then be brought to the blister strip 13a operating in iso-speed for its loading.

This batch 10 will continue until a robot 17 for its setting thermo-forming (trays) 21. Thus, to create the buffer zone 10 and adapt the food supply of the downstream conveyor 13, we choose here: - d ' driving in motion, at different speeds upstream conveyors 19, here the different (in this case two) second successive conveyors, coaxial, 191, 193, - and it is arranged on the upstream conveyor, or all or part of these upstream conveyors 19, at least one door (in this case door 15) that is closed and opened. To manage the buffer zone 10, and thus in this case the closures and openings of the door 15, here we have chosen: - to use several second conveyors, 191 and then 193 in the example, aligned in continuity with each other. other (axially adjacent therefore), - to interpose on all or part of these second conveyors a door 15, pass or not, - to collect information on the movement of said food products on the upper strand of all or part of these second conveyors , via the photocells 25 and / or the camera 23, in the example, - and to adapt the openings and closures of the door 15, depending on the information captured.

In practice, it is recommended that the conveyor 193, which opens on the downstream conveyor 13, rotate a little faster than the one 191 disposed between the conveyors 9 and 193. Thus, the door (forming a retractable abutment) 15 being disposed at the right place. of the second conveyor 193 of the series of second coaxial conveyors 191, 193, it will be possible to create a space 17 allowing the introduction and the opening / closing movement of the door 15.

The (axial) length L of the second conveyor 193 will be such that it can take all the batch of products accumulated in zone 10. If the door 15 is at the entrance of the second conveyor 193, this second conveyor can be stopped as long as the desired batch (quantity) of products grouped in zone 10 is not reached. As for the conveyor 13, it can rotate at the same speed as that 191. According to this solution, the cells 13a of the downstream conveyor 13 are folded in batch of products 1, in the example by batch of six sausages as numbered, with the possibility that two successive batches following each other immediately, hence the possibility in the example of 6xN consecutive products (N, nonzero natural integer). Door 15 opens only when 6xN consecutive products have accumulated behind it. 4th solution (FIGS. 7 and 8): On, but especially downstream of, the production line (first axial conveyor 9 with a smooth band 9a), an accumulation system, for example with a door 15 or with controlled variation (s). (s) speed (s) linked to the upstream conveyor (second group of conveyors 19, each smooth band 19a, aligned -so coaxial-with first axial conveyor 9), retain the sausages 1 longitudinally (along their axis of elongation assumed rectilinear la which is also the common axis of elongation and scroll 11 of the two second consecutive conveyors 191,193), by group or batch 10, before releasing them on the honeycomb conveyor (third conveyor 13) perpendicular which will advance at the time of the discharge of the accumulation to fill all the cells. Thus, to create the buffer zone 10 and adapt the food supply of the downstream conveyor 13, the following are chosen here: to train in motion, at speeds that are varied over time, the whole or part upstream conveyors, here the successive conveyors, coaxial, 9,191,193, and / or to retain the products 1 by a door 15 interposed in the path of the upper band of the two conveyors 191, 193, for example between these conveyors, the closing and opening of the door 15 managing or participating in the management of the flow of the products 1. The four systems developed will require an operator to control the correct filling of the blister strip and to ensure the robot 17 the correct filling trays 21. In each illustrated case, it has been preferred, in order to create the buffer zone 10 and to adapt the food supply of the downstream conveyor 13, to resort to at least a fine control of the batching of the products 1 before loading them onto the Downstream engine 13: solutions 1 to 4: information on the circulation of said products is collected on the upper run of at least some of the upstream conveyors 19, for example via a camera 23 and / or photocells 25, and the velocity or the relative velocities of the upstream conveyor (s) 9/19 and / or the downstream conveyor 13 are adapted according to the sensed information; solutions 3.4: * several second conveyors 191, 193 are used which are aligned in continuity with each other. other, it is interposed on all or part of these second conveyors a door 15 which is opened and closed, via for example a camera 23 and / or photocells 25, it captures information on the movement of said food products 1 on the upper strand of all or part of these second conveyors, and the openings and closures of the door 15 are adapted according to the sensed information.

Finally, it is recalled that a processing electronics 29 will be associated with the information sensors 23, 25 and / or the door (s) 15, if any, to coordinate the modes of action and the operational adjustments (rotational speeds of the conveyors via the motors 31 which drive them, settings of the door 15 ...). Regarding the feeding device of the packaging machine 17,21 long food products, flexible and likely to bend naturally, also to consider here, it will be understood that it will include: - one or more upstream conveyors (9,19 ) without individual or group receiving accommodation of said food products 1 and where these products are placed, at the output of the production line, means 23,25 for regulating the flow of food products circulating on the one or more at least said upstream conveyors 9, 19, to create therein a buffer zone (10) for accumulating said products, - a downstream conveyor 13 provided with housings 13a for receiving, individually or in groups, accumulated food products, for feeding the machine of conditioning. In the following, one or more upstream conveyors, such as 9, 19 may be used, likewise for the (s) downstream conveyors, such as 13. 5th solution (FIGS. 9A to 13B): In these alternatives of the same type of solution, there is accumulation of the products, therefore at least one buffer zone 10, on one, or preferably several, conveyor (s) upstream (s) feeding the (or the) strip (s) blister (s) downstream 13 which is (are) here transverse (s). As illustrated, at least one wide-angle camera 23 and / or photoelectric cells 25 coupled to the processing electronics 29 acting on the drive motors 31 of the conveyors will be suitable. Thus, the food products concerned which run on the upstream (s) 9,19 (191/193), in particular the sausages 1, may in particular be controlled during this scrolling by the or one of the device (s) sensor "visual (s)" 23 and / or 25. As a function of spacing (s) between several products, such as the possible spacing L1 between two successive products at a specific location on an upper strand (FIGS. 9A-13B), will be able to adjust the speed of the downstream honeycomb conveyor, according to the information provided by the sensor (s) 23,25. With each food product leaving production (so just from the machine 7 portioning especially in the case of sausages) spread, because non-compliant (defect of its casing or casing 111 to completely surround the flesh 110, or too curved product, for example, see Figure 15), a L1 type space will be formed on at least one of the conveyor (s) upstream (s) 9,19, at least at the beginning of scrolling sausage flow.

To compensate for this at the downstream conveyor which supplies the robot 17 for trapping the products 1 (as in FIG. 5), the conveyor (s) downstream will then be acted upon, by varying the speed of the scrolling. . In particular, it will be possible to temporarily slow down the downstream conveyor 13 and / or stop it. Thus, if desired, a batch 10 corresponding in number to the capacity of a tray 21 may be loaded in one go by the robot 17 and / or the loading of the downstream conveyor 13 may be total, if desired (each cell can be filled). Instead of a spacing between products (L1), one could for example provide a statement (calculation) speed of the products or the (the) conveyor (s), or a calculation of product flow. Figure 9 is illustrated the case where sausages are in maximum accumulation on the series of upstream conveyors, here all aligned. The downstream honeycomb conveyor 13, here transversal, then scrolls at a constant speed, as shown schematically in FIGS. 11A, 11B. If a short gap L1 is detected between two sausages, the honeycombed conveyor is slowed slightly to catch up (Figs. 12A, 12B).

If a longer gap L10 is detected between two sausages (for example due to two successive rejects), the downstream conveyor 13 will then be slowed down further, if necessary until it stops to wait for the next sausage (FIGS. 13A, 13B).

Note that the creation of the buffer zone 10 by a pilot gate 15 could also be provided, in addition or alternatively, on one (one) of the conveyor (s) upstream, for example on the conveyor 193. The solution of piloted conveyors 19a, 19b, 19c of Figure 4 is also applicable, in combination with the downstream conveyor 13 itself piloted of these Figures 9A to 13B. Right maintenance: In all or some of the aforementioned situations, it is furthermore advised that (here again) means 33 are provided for the straight maintenance of said food products 1 along at least a portion of the upstream conveyor (s) 9, 19 ( a priori the terminal part located just before the access to the downstream conveyor (s)); see Figures 9B, 9D, 10B, 10D. Thus, each product 1 will arrive "straight" (substantially along a common axis) in the elongated cell 13a which presents itself in front of it, transversely. For example, as illustrated, by using means 33 of straight support which will surround at least locally products 1 scrolling, we can either straighten them or maintain substantially straight along at least part of the / upstream conveyors (axis 11) . Figures 9B, 9D, 9E, it is two conveyors chute 33a, 33b between which scroll products 1, in the direction of their length. It can be two endless motorized belts. The trough conveyors 33a, 33b may be only two, located on either side (laterally) of the place where the products run along the conveyor (s) upstream 9 and / or 19. They will advantageously be substantially parallel to each other and to the axis 11 and spaced apart so that the products circulate straight, without being blocked or crushed. As will be understood from the foregoing, the / each upstream conveyor 9, 19, as well as the / each downstream conveyor 13, is arranged flat, in a prior horizontal plane so that the products 1 rest above by simple gravity. However, another solution is illustrated in FIGS. 10B, 10D: replace all or part of the upstream conveyor (s) 9, 19 by, for example, several, such as four, adjacent conveyors: 119a, 119b for the two lower ones arranged in a V following or parallel to the axis 11 and preferably one or two upper conveyors 119c, 119d arranged, in the example, inverted V in the same direction. Thus, these adjacent conveyors will define along the axis 11 a central space 35, which may be square in which is inscribed, in the figure, the diameter of the sausages 1.

One could also imagine a triangle arrangement with an orientation of one of the points down, or not, depending on the preferred choice. Such a passage in chute can therefore apply any flow management solution presented here, such as the following upstream of the downstream conveyor. It can be provided that the electronic processing means 29 act on the means 33 for maintaining the right to scroll more or less quickly, if it is moving strips, such as motorized endless belts. It should be noted that these means 33 for maintaining straight can allow a gain of: - speed of manufacture and / or material on the casing 111 to surround the flesh 110 of the product, - product flow. In fact: - products that are discarded as "non-compliant" are typically those that are curved, - guiding right products allows to aim for high production rates, - guiding right products can aim for envelopes 111 less thick than currently and / or more flexible, without this hindering the production at high rate. heme solution (FIGS. 14A, 14B, 14C): This solution aims to completely fill the trays, such as the one 21 (as in FIG. 5), at the exit of the conveyors, this in a single operation, here via the robot 17. For that a soft strand portion 130 is made on the flexible strip of at least one of the conveyors, here preferably on the downstream conveyor 13, by varying the tension of the conveyor belt and / or its length.

In order to act most effectively on the flow of the products just upstream of the sampling zone by the arm or robot 17, the portion 130 is located between the upstream zone 131 where the products 1 arrive on the conveyor 13 and the downstream zone 133 where the same products come out. Thus, in the illustration in particular of FIG. 14C and on the upper run of the conveyor concerned, the position / zone 131 is that of introduction of the sausage into the cell 13a which receives it and the position / zone 133, that of grip of the robot 17. It will have been noted that, as previously: the position or zone of introduction 131 is at (or immediately ready for) the top of the impeller or input pulley 35a located in front of the adjacent upstream conveyor , here transversely (conveyor 193, FIGS. 14A, 14B), and the position or zone 133 for sampling (by the robot 17 of FIG. 5) is, at the opposite longitudinal end, at (or immediately close to) the top of the For example, if the soft-section portion 130 is not supported, for example (here two) motors 31a, 31b act differently on the honeycomb conveyor 13, one at each end. , we will be able to act on the tension of the upper strand of the band 13 flexible, or deformable, of the conveyor. The head motor 31b (MT, 133 / 35b side) can ensure the advance after each or some sample (s) of product (s) 1 out of the conveyor 13 considered (for example by the robot 17), and the engine of tail 31a (MQ, 131 / 35a side) can ensure the advance after the arrival of / some products on the conveyor. This will result in creating the soft section portion between the setting and removal positions. The upper strand may thus evolve between a substantially tensioned state (mixed treads Figure 14C, at the location of the zone 130) and the relaxed state, with soft strand, materialized by the concave curved zone 130 (solid line). A movable wheel 39, for example following the arrows 41 may also allow to stretch more or less the upper strand and / or catch slack. This portion 130 of soft strand may be managed by a tape tension automatism 37. The automatism 37 can (it) act on the engines.

It will further be possible to combine the solutions with one another, for example: by obtaining the buffer zone 10 by a piloted gate 15, in addition or alternatively, on one of the upstream conveyor (s), on the conveyor 193. The solution of the driven conveyors 19a, 19b, 19c of FIG. 4 is also applicable, in combination with the downstream conveyor 13 itself controlled by these FIGS. 14A to 14C, and / or by functionally linking the automatism 37 and the electronic processing means 29, or the means 23,25. In this regard, it will be possible to vary the speed (s) of rotation of the wheels 35a, 35b and / or the motors 31a, 31b, as a function of the space (s), such as L2, detected between products on the upstream conveyor (s) 9/19. One could also provide that this 6th solution is used alone, independently of the other solutions 1-5, in particular with products (such sausages) as that of Figure 15.

We would then be dealing with a process for feeding a packaging machine with long, flexible, or even naturally curable food products, this process comprising a step where a portion of soft strand (130) is thus created on one side. at least conveyors, by varying the tension of the belt (preferably flexible) of the conveyor and / or the length of the belt. Preferably, this will be created between an upstream zone where the food products (1) arrive on said conveyor and a downstream zone where the food products come out.

Claims (21)

REVENDICATIONS1. A process for feeding a packaging machine into long, flexible and naturally curable food products, the method comprising steps wherein: - the food products (1) are placed on and moved by one or more upstream conveyors (9, 19) on which, or on at least one of which, a buffer zone (10) for accumulation of food products is created, - then the accumulated food products from the upstream conveyor (s) are placed on and moved by a downstream conveyor (13) provided with housings (13a) for individual or grouped reception of the food products, for supplying the packaging machine, characterized in that: - the buffer zone (10): 4 is created on a surface of the upstream conveyor or conveyors without receiving individual or grouped food products, and / or a portion of soft strand (130) on at least one of the conveyors, by varying the tension of the band whose nvoyeur is equipped, and / or the length of this band. 2. Method according to claim 1, wherein: - we use several upstream conveyors comprising a first conveyor (9) and then at least one second conveyor (19), placed one after the other or from each other, each of them having no housing for individual or grouped collection of food products, and - the food products from the first conveyor are then placed on and moved by the second conveyor or second conveyors where the buffer zone (10) for accumulation of food products is created. 3. Method according to claim 2, wherein one or more second conveyors are arranged: in alignment with each other, if there are several, and transversely with respect to the first conveyor. 4. Method according to one of claims 1 to 3, which ensures a total filling of the food products housing (13a) for receiving the downstream conveyor. 5. Method according to one of claims 1 to 3, which ensures a batch filling (10) of food products receiving housing (13a) of the downstream conveyor. 6. Method according to one of claims 1 to 4 wherein, to create the buffer zone (10) and adapt the food supply of the downstream conveyor, it captures (23,25) information on the circulation of said food products on the upper end of at least some of the upstream conveyors (9, 19) and the speed or the relative speeds of the upstream conveyor (s) and / or the downstream conveyor (13) are adapted according to the sensed information. 7. Method according to one of claims 1 to 6 wherein, to create the buffer zone and adapt the food supply of the downstream conveyor: - is moved in the or all or part of the conveyor (s) upstream, at a constant speed, and driving the downstream conveyor at a constant speed, which may be the same as that of the upstream conveyor (s), except at certain times when said downstream conveyor speed is slowed down, when it has a deficit of food products in the buffer zone (10). 8. A method according to claim 2, or claim 2 and one of claims 3 to 5, wherein a plurality of second conveyors aligned following each other are used and said second conveyors are driven in motion at different relative speeds. 9. Method according to one of claims 1 to 8 wherein, to create the buffer zone and adapt the food supply of the downstream conveyor: - it drives in movement or all or part of the upstream conveyors at speeds that the it is varied in time, and / or is arranged on the upstream conveyor, or all or part of the upstream conveyors, at least one door (15) that is closed and opens. 10. A method according to claim 2, or claim 2 and one of claims 3 to 5, wherein, to create the buffer zone and adapt the food supply of the downstream conveyor: - several second conveyors are used aligned in the continuity of each other, - is placed on all or part of these second conveyors a door (15) that is opened and closed, - it captures information on the movement of said food products on the upper strand of all or part of these second conveyors, - and adapted according to the information received openings and closures of the door. 11. The method of claim 2, or claim 2 and one of claims 3 to 10, wherein the second conveyor or second conveyors is moved so that the food products move with them parallel to the direction of elongation of said products. fed to this or these second conveyors and on the downstream conveyor, the food products are moved perpendicularly their direction of elongation. 12. Method according to one of claims 1 to 11 wherein the downstream conveyor distributes the food products to a robot manipulator of the packaging machine which loads food products from the downstream conveyor trays. 13. The method of claim 2, or claim 2 and one of claims 3 to 12, wherein the first conveyor receives the food immediately output of the production line. 14. Method according to one of claims 1,2,4,5,11,12,13, where it captures (23,25) information on the scroll of the conveyor or upstream conveyors (9,19) or food products (1) on this or these upstream conveyors, and the speed of the downstreamconverter (s) (13) is adapted according to the information collected, by a slowdown or by a stop, at least momentary, of this or these downstream conveyors (13). 15. Method according to one of claims 6 or 14, wherein the step of sensing information comprises that of sensing a spacing between food products (1) traveling on the conveyor or upstream (9,19). 16. Method according to one of claims 1 to 15 wherein used as food products (1) placed on and moved by the conveyors are (9,19) fresh sausages each wrapped with a natural gut. 17. Method according to one of claims 1 to 15 wherein said food products (1) are straightened or kept substantially rectilinear along at least part of the upstream conveyor (9, 19) by passing them through means (33) for maintaining straight. 18. The method of claim 12 wherein the portion of soft strand (130) is created between an upstream zone where the food products (1) arrive on said conveyor and a downstream zone where the food products (1) come out, taken by the robot (17). 19. Device for supplying, in long, flexible and naturally curable food products, a packaging machine, the device comprising: - one or more upstream conveyors (9, 19) without receiving receptacles (13a) individual or group of said food products (1) and where these products are placed at the output of the production line, - a downstream conveyor (13) provided with housings (13a) for individual or group receipt of accumulated food products, to feed the machine for packaging, and a buffer zone (10) for accumulating said products created by means for regulating the flow rate of the food products (1) circulating on the or at least one of said upstream conveyors (9, 19) and / or by a portion of soft strand (130) on one of the conveyors, which has a flexible moving band. 20. Device according to claim 19 which comprises means (33) for maintaining said food products (1) along at least a portion of the upstream conveyor (9,19). 21. Device according to claim 19 or 20, wherein the soft strand portion (130) is obtained by motors (31a, 31b) acting differently on one of the conveyors, with a downstream motor (31b) which provides the advancing the belt after at least one product sample (1) out of the conveyor and an upstream motor (31a) which provides advance after the arrival of at least one of said products on the conveyor. 30