Installation for manufacturing a calendered skim ply comprising reinforcing filaments

Abstract

The invention relates to an installation for manufacturing a calendered skim ply made of rubber material and comprising reinforcing filaments, the manufacturing installation comprising, from upstream to downstream: at least two feed racks each delivering their own series of reinforcing filaments, the manufacturing installation using a single series of reinforcing filaments for the manufacture of a calendered skim ply, at least one filament-laying device associated with each feed rack, a calender for assembling the series of reinforcing filaments originating from the same feed rack with a rubber material so as to form a calendered skim ply made of rubber material comprising said reinforcing filaments, and a device for cooling the calendered skim ply. The manufacturing installation comprises a first accumulator situated between the calender and the device for cooling the calendered skim ply, this first accumulator making it possible to accumulate less than 10 meters, and preferably up to 6 meters, of calendered skim ply and being used to allow the calendered skim ply to return back through the calender in a downstream-to-upstream direction.

Description

INSTALLATION FOR PRODUCING A CALENDERED FABRIC COMPRISING REINFORCING THREADS

[0001] The present invention relates to the manufacture of a calendered sheet, preferably made from a rubbery material, and comprising reinforcing threads which may be of a textile or metallic nature.

[0002] By rubbery material is meant a rubber-based material, unvulcanized and further comprising other components such as fillers, oils, silica, carbon black, etc.

[0003] Reinforced rubber sheets are used, for example, in the manufacture of tires, and more specifically in the production of tire blanks which are then transformed into tires during a baking cycle in a mold.

[0004] More specifically, the invention relates to changes in reinforcement series in a plant for manufacturing reinforced sheets of rubber material. These changes take place to change the dimensions or nature of the reinforcement, or because the supply rack of the plant has been emptied and can no longer supply reinforcement wires.

[0005] Since they involve a shutdown of the manufacturing facility, the goal is generally to reduce the time required to carry out these series changes.

[0006] Document EP3369543 relates to an installation for manufacturing calendered sheets, made of rubber material and comprising reinforcing threads.

[0007] According to this document EP3369543, the manufacturing installation comprises at least two reinforcement wire supply racks, various mobile trolleys equipped with wire laying devices, a calender and a cooling unit.

[0008] When changing the series of reinforcing wires in such an installation, it is necessary to secure the rear ends of the reinforcing wires of the previous series to the front ends of the reinforcing wires of the following series, in order to be able to drive the wires of the following series through the calender and all the other devices present in the installation to the final winding roller of the calendered sheet.

[0009] To perform this joining of the rear ends of the reinforcing wires of the previous series to the front ends of the reinforcing wires of the following series, document EP3369543 provides for the use of a splicer that is mobile between a waiting position located away from the reinforcing wires and a joining position in which it is located at the level of the reinforcing wires to be joined. In more detail, document EP3369543 provides for the use of a rubber sheet in the splicer to perform the joining between the wires of the previous series and the wires of the following series. When the splicer is in its joining position, the operator first places the rubber sheet in the splicer, then places the rear ends of the reinforcing wires of the previous series and the front ends of the reinforcing wires of the following series on the rubber sheet, and finally performs the joining with the splicer.

[0010] To complete the joint, the splicer must cure the rubber sheet to vulcanize the rubber material around the ends of the reinforcement wires. This curing step increases the time required to complete the joint and penalizes the productivity of the manufacturing facility by extending the plant downtime.

[0011] According to another disadvantage, the joining method used in document EP3369543 requires the operator to carry out a precise placement of the ends of the reinforcement wires in the splicer to guarantee a correct connection between the reinforcements and to ensure the integrity of the future calendered sheet with respect to the placement of the reinforcement wires relative to each other. This precise placement of the ends of the reinforcement wires is carried out by the operator while the manufacturing installation is stopped, therefore it also increases the time required to carry out the joining and penalizes the productivity of the manufacturing facility. In addition, it should be noted that the precise placement of the ends of the reinforcement wires relative to each other will require more operator time when the reinforcement wires of the next series differ in diameter, number and / or pitch deviation from the reinforcement wires of the previous series.

[0012] Finally, in the joining method proposed in document EP3369543, and before proceeding with the joining of the ends of the reinforcing wires in the splicer, the operator must extract the ends of the reinforcing wires of the previous series located under a pressing roller and place them above this pressing roller and another roller. This manipulation can prove complex for the operator given the large number of reinforcing wires, a calendered sheet generally comprising between 1000 and 2000 reinforcing wires.

[0013] The present invention aims to overcome the drawbacks of the solution proposed in document EP3369543 by proposing an installation and a method for manufacturing a calendered sheet in which the method of changing the series of reinforcing threads is faster and easier to implement.

[0014] At the same time, the installation and the manufacturing process of a calendered sheet according to the invention also make it possible to limit the waste of reinforcing threads when changing the series of reinforcing threads, and therefore to limit material losses from the installation.

[0015] To this end, the invention relates to an installation for manufacturing a calendered sheet of rubber material and comprising reinforcing threads, the manufacturing installation comprising from upstream to downstream: - at least two feed racks each delivering their own series (A, B) of reinforcing wires, the manufacturing facility using a single series of reinforcing wires for the manufacture of a calendered web, - at least one wire laying device associated with each power supply rack, - a calender for assembling the series of reinforcing wires from the same feed rack with a rubbery material and so as to form a calendered sheet of rubbery material comprising said reinforcing wires, and - a device for cooling the calendered sheet.

[0016] According to the invention, the manufacturing installation is characterized in that it comprises a first accumulator located between the calender and the device for cooling the calendered sheet, this first accumulator making it possible to accumulate less than 10 meters, and preferably up to 6 meters, of calendered sheet and being used to allow a return of the calendered sheet from downstream to upstream through the calender.

[0017] Advantageously, but not necessarily, it may also be provided in the installation that: - each wire laying device is mobile between the rack to which it is associated and the calender, - each wire-laying device is movable between a preparation position located near the rack with which it is associated and a production position located near the calender, - each wire-laying device is movable in translation parallel to the upstream-downstream direction in which the various devices of the manufacturing installation are arranged, - each wire-laying device is movable in translation in a transverse direction perpendicular to the upstream-downstream direction in which the various devices of the manufacturing installation are arranged.

[0018] The invention also relates to a method for manufacturing a calendered sheet made of rubber material and comprising reinforcing threads used with the manufacturing installation according to the invention.

[0019] According to the invention, this manufacturing method is implemented with a method of changing the series of reinforcing wires in which a non-zero length of the calendered sheet manufactured with the previous series of reinforcing wires is driven backward and from downstream to upstream when changing series of reinforcing wires.

[0020] In this manufacturing process, the method of changing the series of reinforcing wires may also provide for preparing the ends of the reinforcing wires of the new series while the reinforcing wires of the previous series are used by the calender to produce a calendered sheet, this preparation consisting of positioning in an orderly manner the ends of the reinforcing wires of the new series on a first wire-laying device, then fixing the positions of the ends of the reinforcing wires of the new series relative to each other.

[0021] In this manufacturing process, once the reinforcing wires of the new series have been prepared on the first wire-laying device, the method for changing the series of reinforcing wires may provide: - to stop pulling the previous series of reinforcement wires and to move the second wire-laying device backwards and from downstream to upstream, then - to cut the previous series of reinforcement wires between the second wire laying device and the calender, and - to evacuate the second wire laying device.

[0022] Following the evacuation of the second wire laying device, the method of changing the series of reinforcement wires may provide: - to position the first wire laying device and the first feed rack in the axis of the calender, then - to move the first wire-laying device and the prepared ends of the reinforcement wires of the new series to the production position located near the calender, and - to drive backwards and from downstream to upstream a non-zero length of the calendered sheet manufactured with the previous series of reinforcement wires.

[0023] After the calendered sheet made with the previous series of reinforcing wires has been returned upstream and downstream, the method of changing the series of reinforcing wires may provide for assembling the ends of the reinforcing wires of the new series prepared with the two sheets of rubber material to the sheet made with the reinforcing wires of the previous series.

[0024] Other characteristics and advantages of the invention will appear in the description which follows. This description, given by way of example and not as a limitation, refers to the attached drawings in which: - [Fig.l] is a schematic representation of a front view of a manufacturing installation according to the invention, without its feed racks, - [Fig.2] is a schematic representation of a top view of the feed racks of a manufacturing installation according to the invention, - [Fig.3] is a schematic front view of a first step leading to the cutting of the previous series of reinforcing wires, - [Fig.4] schematically represents a top view of the cutting of the previous series of reinforcing wires, - [Fig.5] schematically represents a front view of the cutting of the previous series of reinforcing wires, - [Fig.6] schematically represents in top view a step prior to the assembly of the reinforcing wires of the new series with the length of calendered sheet which has just been drawn back, - [Fig.7] schematically represents in front view a step prior to the assembly of the reinforcing wires of the new series with the length of calendered sheet which has just been drawn back, - [Fig.8] schematically represents in front view the assembly of the reinforcing wires of the new series with the length of calendered sheet which has just been drawn back, - [Fig.9] schematically represents in front view a step of opening the calender necessary for restarting the production of a calendered sheet with the new series of reinforcing wires, and - [Fig.10] schematically represents in front view a final stage necessary for restarting the production of a calendered sheet with the new series of reinforcing wires.

[0025] The invention relates to the manufacture of a calendered sheet 12, preferably made of a rubbery material, and comprising reinforcing threads 14 which may be of a textile or metallic nature. For example, the reinforcing threads 14 are metallic or synthetic cables. For example, a calendered sheet manufactured according to the invention comprises between 1000 and 2000 reinforcing threads arranged substantially parallel to each other and in a single layer in the rubbery material.

[0026] The rubbery material from which a calendered sheet according to the invention can be manufactured is a rubber-based material, unvulcanized and also comprising other components such as fillers, oils, silica, carbon black, etc.

[0027] Preferably, the reinforcing threads are entirely encased in the rubber material. Preferably, each reinforcing thread is located substantially equidistant from the lower and upper surfaces of the calendered web. For example, a calendered web according to the invention has a thickness of between 0.6 and 10 mm. For example, the reinforcing threads have a diameter of between 0.3 and 5 mm. For example, the reinforcing threads present in a calendered web according to the invention all have the same diameter.

[0028] The manufacturing installation according to the invention makes it possible, for example, to manufacture calendered plies used for the manufacture of tires, and more specifically for the production of tire blanks which are then transformed into tires during a baking cycle in a mold.

[0029] As shown in Figures 1 and 2, the manufacturing installation 10 of a calendered sheet 12 according to the invention comprises from upstream to downstream (see arrow F in the figures): - at least two supply racks 16A, 16B each delivering their own series A, B of reinforcement wires 14, - at least one wire-laying device 18A, 18B associated with each supply rack, and - a calender 20 making it possible to assemble the series of reinforcing wires coming from the same supply rack with a rubbery material and so as to form a calendered sheet of rubbery material comprising said reinforcing wires.

[0030] A feed rack 16A, 16B comprises a plurality of supports receiving a plurality of spools of reinforcement wires and means for guiding each wire from its respective spool to the outlet of the rack. Preferably, the outlet of the rack is equipped with a device allowing an orderly outlet of the reinforcement wires.

[0031] The feed racks 18A, 18B of the installation can be juxtaposed as illustrated in Figure 2. Alternatively, the racks could be superimposed or arranged in any other configuration allowing them to supply the calender in turn with reinforcing wires. Advantageously, the feed racks 18A, 18B are mounted movably so as to be able to invert their position and position themselves in the axis of the calender 20 to supply it. For example, the feed racks 18A, 18B are movable in translation. For example, the feed racks 18A, 18B can be mounted movably in translation in a transverse direction DT perpendicular to the upstream-downstream direction.

[0032] In the present invention, the manufacturing facility 10 uses only one set of reinforcing yarns at a time for manufacturing a calendered web 12.

[0033] A wire laying device 18A, 18B comprises at least one grooved roller and a device for locking the ends of the reinforcement wires in an ordered position relative to each other, such as for example a clamping or magnetic device. In addition, combs for guiding the reinforcement wires can be added to the wire laying device. Each wire laying device 18A, 18B offers a configuration adapted to the number, size and nature of the reinforcement wires in the series delivered by the feed rack with which it is associated.

[0034] The calender 20 is preferably a four-roll calender. This calender 20 is fed by two extrusion devices, such as cylinder tools for example, and it makes it possible to form two intermediate plies of rubber material between which the reinforcing threads are inserted. For example, each extrusion device is associated with two rollers of the calender. The two upper rollers of the calender are for example associated with a first extrusion device to generate an upper intermediate ply, and the two lower rollers of the calender are for example associated with the second extrusion device to generate a lower intermediate ply. Advantageously, the lowest of the upper rollers and the highest of the lower rollers are used to assemble the reinforcing threads with the lower intermediate ply and the upper intermediate ply.For this purpose, the upper intermediate ply, the reinforcing wires and the lower intermediate ply pass between the lowest of the upper rollers and the highest of the lower rollers.

[0035] Preferably, a device 28 for cooling the calendered sheet is provided downstream of the calender 20. This cooling device 28 comprises, for example, cooled rollers (not shown) around which and / or on which the calendered sheet circulates. For example, the rollers of the cooling device are cooled by being passed through by a cooling fluid.

[0036] According to the invention, and in order to facilitate the implementation of a change of series of reinforcing wires, the manufacturing installation 10 comprises a first accumulator 22 located between the calender 20 and the device 28 for cooling the calendered sheet, this first accumulator making it possible to accumulate less than 10 meters, and preferably up to 6 meters, of calendered sheet and being used to allow a return backward of the calendered sheet from downstream to upstream through the calender.

[0037] After cooling, the calendered sheet 12 is stored on a storage reel 26 provided at the end of the manufacturing installation 10.

[0038] Advantageously, the manufacturing installation 10 may also comprise a second accumulator 24 making it possible to accumulate several tens of meters of calendered sheet 12. This second accumulator 24 is for example interposed between the cooling device 28 and the storage reel 26 located at the end of the manufacturing installation. This second accumulator 24 is used to keep the calendered sheet under tension during manufacturing and to temporarily store a large length of calendered sheet during a change of storage reel 26.

[0039] According to the invention, each wire laying device 18A, 18B is movable between the rack with which it is associated and the calender 20. For this purpose, each wire laying device 18A, 18B is for example mounted on a mobile carriage 30 having its own means of locomotion. Alternatively, each wire laying device 18A, 18B could be mounted on rails or any other suitable guide means and driven in its movements by actuators such as a motor and one or more jacks.

[0040] This mobility of the wire laying devices 18A, 18B is intended to allow the removal of the wire laying device which has just been used to supply the calender and its replacement by another wire laying device when changing the series of reinforcing wires.

[0041] In more detail, each wire-laying device 18A, 18B is movable between a preparation position PRE located near the rack with which it is associated and a production position PRO located near the calender. In the example illustrated in FIG. 2, the first wire-laying device 18A is located in the preparation position PRE located near the rack 16A with which it is associated, and the second wire-laying device 18B is located in the production position PRO located near the calender 20.

[0042] For example, each wire-laying device 18A, 18B is movable in translation parallel to the upstream-downstream direction (see arrow F in figure 1) in which the different wire-laying devices are arranged. the manufacturing facility: calender 20, first accumulator 22, cooling device 28, second accumulator 24, and storage coil 26.

[0043] In addition, each wire-laying device 18A, 18B can also be movable in translation in a transverse direction DT perpendicular to the upstream-downstream direction.

[0044] The invention also covers a method for manufacturing a calendered sheet which is implemented with the manufacturing installation which has just been described and with a method for changing the series of reinforcing threads specific to the invention and adapted to this manufacturing installation. This method for changing the series of reinforcing threads advantageously uses the first accumulator 22 making it possible to accumulate up to 6 meters of calendered sheet 12 to drive backwards and from downstream to upstream a non-zero length of the calendered sheet manufactured with the previous series of reinforcing threads during a change of series of reinforcing threads.

[0045] Different phases and steps of this manufacturing process and method of changing the series of reinforcing wires are illustrated in Figures 1 to 10. PRODUCTION

[0046] In the production phase illustrated by Figures 1 and 2, the second feed rack 16B is used to feed the calender 20 with reinforcement wire of series B via the second wire laying device 18B. The second wire laying device 18B is located in the production position PRO located near the calender and the calender 20 is closed. During this production step, the reinforcement wires 14 are driven from upstream to downstream (see arrow F in Figure 1) through the calender 20 to be assembled with the rubber material and thus form the calendered sheet 12. The calendered sheet 12 is also driven from upstream to downstream (see arrow F in Figure 1) to pass through the first accumulator 22, through the cooling device 28, then through the second accumulator 24 and end up wound on the storage reel 26.During this production phase, the reinforcing wires 14 and the calendered sheet 12 are pulled from upstream to downstream by rotating the rollers of the calender 20 and the storage reel 26, this storage reel 26 being, for example, motorized for this purpose.

[0047] According to an important point of the invention, when the manufacturing installation is in a production phase, the first accumulator 22 is in an extended configuration which allows it to accumulate a maximum length of calendered web. For example, when it is in an extended configuration, the first accumulator 22 makes it possible to accumulate a length of calendered web of up to 6 meters. For example, in the case where this first accumulator 22 comprises two upper rollers and a lower roller between which the calendered web circulates, the lower roller is in a low position distant from the upper rollers when the first accumulator 22 is in its extended configuration. PREPARATION

[0048] During this production phase with the previous series B of reinforcement wires supplied by the second supply rack 16B, the new series A of reinforcement wires supplied by the first supply rack 16A can be prepared in masked time and without requiring a shutdown of the manufacturing facility.

[0049] This step of preparing the new series A of reinforcing wires is for example carried out using the first wire-laying device 18A associated with the first supply rack 16A. In more detail, the ends of the reinforcing wires 14 of the new series A are positioned in an orderly manner on the first wire-laying device 18A, then the position of the ends of the reinforcing wires of the new series A relative to each other is fixed. For this purpose, the changing method according to the invention provides for immobilizing the ends of the reinforcing wires of the new series A between two sheets of rubber material and to fix this assembly by vulcanization. In more detail, this assembly by vulcanization of the ends of the reinforcement wires of the new series A with two sheets of rubber material is carried out by an operator using a splicer 19 which is also part of the manufacturing installation 10. This splicer 19 is mobile and it can be received by the first wire laying device 18A located in the preparation position PRE in front of its supply rack 16A, and for example between the grooved roller and the device for locking the reinforcement wires of this wire laying device. Of course, the splicer 19 can also be received by the second wire laying device 18B when the latter is located in the preparation position PRE in front of the second supply rack 16B.

[0050] When the preparation of the ends of the reinforcement wires of the new series is completed, the splicer is moved away from the wire laying device.

[0051] This step of preparing the ends of the new reinforcing wires constitutes a first step in the method of changing the series of reinforcing wires according to the invention.

[0052] The method of changing the series of reinforcing wires according to the invention therefore provides for preparing the ends of the reinforcing wires of the new series while the reinforcing wires of the previous series are used by the calender to produce a calendered sheet. PRODUCTION STOP

[0053] Once the reinforcing wires 14 of the new series A have been prepared on the first wire-laying device 18A, the production cycle can be stopped to carry out the other steps of the method for changing the series of reinforcing wires according to the invention.

[0054] In a second step, the method for changing the series of reinforcing wires provides for stopping the drawing of the previous series B and moving the second wire laying device 18B backwards, that is to say from downstream to upstream (arrow R in figure 3), by a horizontal distance of approximately 2 meters for example. This backward movement of the second wire laying device 18B is carried out through the reinforcing wires of the previous series B. During this horizontal backward movement, the second wire laying device 18B moves away from the calender 20, by approximately 2 meters for example. During this second step, the first accumulator 22 remains in its extended configuration. CUT

[0055] In a third step and as illustrated in Figure 4, the method for changing the series of reinforcing wires according to the invention provides for cutting the previous series B of reinforcing wires between the second wire laying device 18B and the calender 20. This cutting is for example carried out by an operator using a shear-type cutting tool. Once the cutting of the reinforcing wires of the previous series B has been carried out, the second wire laying device 18B is removed, for example by being moved away from the calender 20 again by another movement towards the rear and from downstream to upstream. The second wire laying device 18B is for example returned to its preparation position PRE located near the rack 16B with which it is associated, as illustrated in Figure 5. Optionally, this return movement of the wire laying device 18B towards its position PRE may also comprise a movement in a transverse direction DT perpendicular to the upstream-downstream direction.As shown in Figure 5, during this third step, the first accumulator 22 is still in its extended configuration. FEED RACK CHANGE

[0056] In a fourth step, and following the evacuation of the second wire laying device 18B towards the second supply rack 16B, the method of changing the series of reinforcement wires provides: - to position the first wire-laying device 18A and the first feed rack 16A in the axis of the calender 20, for example by translating these devices in the transverse direction DT perpendicular to the upstream-downstream direction, then - to move the first wire-laying device 18A and the prepared ends of the reinforcement wires of the new A series to the production position PRO located near the calender 20, and - to drive backwards and from downstream to upstream a non-zero length L of the calendered sheet 12 manufactured with the previous series B of reinforcing wires (see figure 6).

[0057] The return back of the calendered web manufactured with the previous series B of reinforcement wires is enabled by the first accumulator 22. In more detail, the non-zero length L of the calendered web 12 which is driven backward is delivered by the first accumulator 22 which passes from its extended position to a retracted position in which it allows a minimum length of calendered web to be stored. This retracted position of the first accumulator is illustrated in Figure 7. For example, in the case where this first accumulator 22 comprises two upper rollers and a lower roller between which the calendered web circulates, the lower roller is in a high position close to the upper rollers when the first accumulator 22 is in its retracted position.

[0058] For example, the backward and upstream movement of the calendered web 12 can be achieved by means of the calender 20 and its rollers. For example, in the case where the calender comprises four rollers, the lowest of the upper rollers and the highest of the lower rollers are rotated in the opposite direction to the direction in which they rotate during the production phase to pull the calendered web forward and from upstream to downstream.

[0059] Alternatively, the backward and downstream movement of the calendered sheet 12 can be carried out manually by an operator or with the aid of an external pulling device. In this case, the calender 20 is opened before the backward pulling. ASSEMBLY

[0060] In a fifth step, and after the calendered ply 12 manufactured with the previous series B of reinforcing wires has been returned backwards and from downstream to upstream, the method for changing the series of reinforcing wires provides for assembling the ends of the reinforcing wires of the new series A prepared with the two sheets of rubber material to the ply manufactured with the reinforcing wires of the previous series, and more precisely to the end of the non-zero length L of the calendered ply which has just been driven backwards and from downstream to upstream.This assembly can be carried out by pressing the ends of the reinforcing wires of the new series prepared with the rubber material sheets onto the end of the calendered ply manufactured with the previous series of reinforcing wires, or conversely by pressing the end of the calendered ply manufactured with the previous series of reinforcing wires onto the ends of the reinforcing wires of the new series prepared with the rubber material sheets. This pressurization can be carried out manually by an operator because it does not require the application of significant force. Optionally, a solution intended to make the rubber material more adhesive can be applied to the rubber material sheets enclosing the ends of the reinforcing wires of the new series and / or to the end of the calendered ply manufactured with the previous series of reinforcing wires to reinforce their assembly.As shown in Figure 8, a movable table 32 can be positioned between the first wire laying device 18A and the calender 20.

[0061] This assembly solution is advantageous because, firstly, it does not require a vulcanization step while the installation is stopped, and secondly, because it remains easy and quick to implement when the nature, diameter and / or number of reinforcing wires are very different from one series to another. RESTART

[0062] In a sixth step, the method of changing the series of reinforcing wires aims to restart the production of the calendered sheet 12, but with the reinforcing wires of the new series A.

[0063] For this purpose, during this sixth step, the method for changing the series of reinforcing wires provides for opening the calender 20, putting the calendered sheet 12 back under tension, and then closing the calender 20. The opening of the calender 20 is obtained by moving the two rollers of the calender apart from each other, which allow the reinforcing wires and the intermediate sheets to be assembled when the calender is closed. The tensioning of the calendered sheet 12 is obtained using the first accumulator 22. In more detail, the first accumulator 22 returns to its extended position, as shown in Figure 9.

[0064] Finally, during this sixth step, the method for changing the series of reinforcing wires also provides for bringing the first wire-laying device 18A into contact with the calender 20, and more precisely into contact with one of its rollers. This position of the first wire-laying device 18A against the calender 20, illustrated in FIG. 10, corresponds to its production position PRO. Of course, this production position PRO is also that of the second wire-laying device 18B when it is used to supply the calender with reinforcing wires. Advantageously, the speed of movement of the first wire-laying device 18A towards the calender 20 is controlled by the drawing speed of the calendered sheet 12.

[0065] Once the first wire-laying device 18A is in contact with the calender 20, the manufacturing cycle of a calendered sheet can be restarted with the new series of reinforcing wires.

[0066] Once this new series A of reinforcing wires has been exhausted or production has simply stopped, a new change of series of reinforcing wires can take place on the same principle and following the same steps which have just been described. For this, it is sufficient to transpose the movements of the second wire-laying device 18B to the first wire-laying device 18A, and the movements of the second supply rack 16B to the first supply rack 16A.

[0067] Thanks to the method of changing the series of reinforcing threads according to the invention, the calendered sheet which is manufactured immediately after a change of series of reinforcing threads is compliant from the first meters, which makes it possible to greatly limit material losses, particularly in comparison with the methods of the prior art.

Claims

CLAIMS 1. Manufacturing installation (10) of a calendered sheet (12) made of rubber material and comprising reinforcing threads (14), the manufacturing installation comprising from upstream to downstream: - at least two feed racks (16A, 16B) each delivering their own series (A, B) of reinforcing wires, the manufacturing installation using a single series of reinforcing wires for the manufacture of a calendered sheet, - at least one wire laying device (18A, 18B) associated with each supply rack, - a calender (20) for assembling the series of reinforcing wires from the same feed rack with a rubbery material and so as to form a calendered sheet of rubbery material comprising said reinforcing wires, and a device (28) for cooling the calendered sheet, the manufacturing installation is characterized in that it comprises a first accumulator (22) located between the calender (20) and the device (28) for cooling the calendered sheet, this first accumulator making it possible to accumulate less than 10 meters, and preferably up to 6 meters, of calendered sheet and being used to allow a return backward of the calendered sheet from downstream to upstream through the calender.

2. Manufacturing installation according to claim 1, in which each wire laying device (18A, 18B) is movable between the rack with which it is associated and the calender.

3. Manufacturing installation according to claim 2, in which each wire-laying device (18A, 18B) is movable between a preparation position (PRE) located near the rack with which it is associated and a production position (PRO) located near the calender.

4. Manufacturing installation according to claim 2 or claim 3, in which each wire-laying device (18A, 18B) is movable in translation parallel to the upstream-downstream direction in which the different devices of the manufacturing installation are arranged.

5. Manufacturing installation according to one of claims 2 to 4, in which each wire-laying device (18A, 18B) is movable in translation in a transverse direction (DT) perpendicular to the upstream-downstream direction in which the different devices of the manufacturing installation are arranged.

6. Method for manufacturing a calendered sheet of rubber material and comprising reinforcing threads, the manufacturing method being characterized in that it is implemented with a manufacturing installation according to one of the preceding claims and with a method for changing the series of reinforcing threads in which a non-zero length of the calendered sheet manufactured with the previous series of reinforcing threads is driven backwards and from downstream to upstream during a change of series of reinforcing threads.

7. Manufacturing method according to claim 6, in which the method for changing the series of reinforcing wires provides for preparing the ends of the reinforcing wires of the new series while the reinforcing wires of the previous series are used by the calender to produce a calendered sheet, this preparation consisting of positioning in an orderly manner the ends of the reinforcing wires of the new series on a first wire-laying device, then fixing the position of the ends of the reinforcing wires of the new series relative to each other.

8. Manufacturing method according to claim 7, in which, once the reinforcing wires of the new series have been prepared on the first wire-laying device, the method for changing the series of reinforcing wires provides: - to stop pulling the previous series of reinforcement wires and to move the second wire laying device backwards and from downstream to upstream, then - to cut the previous series of reinforcement wires between the second wire laying device and the calender, and - to evacuate the second wire laying device.

9. Manufacturing method according to claim 8, in which, following the evacuation of the second wire-laying device, the method for changing the series of reinforcing wires provides: - to position the first wire laying device and the first feed rack in the axis of the calender, then - to move the first wire-laying device and the prepared ends of the reinforcement wires of the new series to the production position located near the calender, and - to drive backwards and from downstream to upstream a non-zero length of the calendered sheet manufactured with the previous series of reinforcement wires.

10. Manufacturing method according to claim 9, in which, after the return backward and downstream upstream of the calendered sheet manufactured with the previous series of reinforcing threads, the method of changing the series of reinforcing threads provides for assembling the ends of the reinforcing threads of the new series prepared with the two sheets of rubber material to the sheet manufactured with the reinforcing threads of the previous series.

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