CALENDERING FACILITY FOR REINFORCEMENT PLIES FOR TIRES

Abstract

Calendering installation for the production of a reinforcing ply (600) for a tire, which has a frame (100), two extruders (200, 300) for feeding elastomer material, a reinforcing-thread feeding device (400), a calender (500) having a first pair of counter-rotating rollers, with a first working roller (52) and a first shaping roller (51), and a second pair of counter-rotating rollers, with a second working roller (53) and a second shaping roller (54), wherein a calendering nip (59) is formed between the working rolls (52, 53) in order to receive a first calendered rubber ply (57) delivered by the first pair of rollers (51, 52), a second calendered rubber ply (58) delivered by the second pair of rollers (53, 54), and the reinforcing threads (45) in order to supply the calendered reinforcing ply (600), which is conveyed to the outlet of the installation via guide rollers (62, 63).

According to the invention, the two extruders (200, 300) are superposed and arranged on either side of a horizontal plane P extending at the level of the guide rollers (62, 63).

Claims

1-14. (canceled)

15. A calendering installation for producing a reinforcing ply for a tire, the installation comprising: a frame; an outlet; two extruders supported by the frame, each extruder being structured for feeding an elastomer material; a calender; guide rollers; first and second flat dies; and a reinforcing-thread feeder structured to convey reinforcing threads into the calender, wherein the calender includes: a first pair of counter-rotating rollers formed of a first working roller and a first shaping roller, a second pair of counter-rotating rollers formed of a second working roller and a second shaping roller, wherein the first flat die is positioned between the first extruder and the first pair of counter-rotating rollers, and the first flat die projects into a first rubber-ply calendering nip located between the first pair of counter-rotating rollers, wherein the second flat die is positioned between the second extruder and the second pair of counter-rotating rollers, and the second flat die projects into a second rubber-ply calendering nip located between the second pair of counter-rotating rollers, wherein a calendering nip is formed between the first and second working rollers and is positioned to receive: a first calendered rubber ply delivered by the first pair of counter-rotating rollers, a second calendered rubber ply delivered by the second pair of counter-rotating rollers, and the reinforcing threads conveyed by the reinforcing-thread feeder, wherein the calendaring nip produces a calendered reinforcing ply from the first and second calendered rubber plies and the reinforcing threads, wherein the calendered reinforcing ply is conveyed to the outlet via the guide rollers, and wherein the two extruders are superposed and are arranged on opposite sides of a horizontal plane P that extends at a level of the guide rollers.

16. The installation according to claim 15, wherein the first extruder outputs an elastomer mixture into a first nip, formed by the first pair of counter-rotating rollers, at a pressure greater than atmospheric pressure, and wherein the second extruder outputs an elastomer mixture into a second nip, formed by the second pair of counter-rotating rollers, at the pressure greater than atmospheric pressure.

17. The installation according to claim 15, wherein that the first extruder has a longitudinal axis X-X and the second extruder has a longitudinal axis Y-Y, wherein the first extruder is arranged such that the axis X-X intersects the horizontal plane P at an angle , wherein the second extruder is arranged such that the axis Y-Y intersects the horizontal plane P at an angle , and wherein the angle and the angle have a same vertex and one common side.

18. The installation according to claim 17, wherein the axis X-X and the axis Y-Y make an angle of between 10 and 90 with each other.

19. The installation according to claim 15, wherein the horizontal plane P is situated at a distance of between 800 mm and 1400 mm from a base of the frame.

20. The installation according to claim 15, wherein the first extruder includes a first feeding device that is arranged to be close to the horizontal plane P, and wherein the second extruder includes a second feeding device that is arranged to be close to the horizontal plane P.

21. The installation according to claim 15, wherein the first extruder, the first flat die, and the first pair of counter-rotating rollers form a first assembly mounted on a first common frame, and wherein the second extruder, the second flat die, and the second pair of counter-rotating rollers form a second assembly mounted on a second common frame.

22. The installation according to claim 15, wherein the first pair of counter-rotating rollers are held by a first bracket mounted in a fixed manner on the first common frame, with the first extruder being axially movable with respect to the first bracket, and wherein the second pair of counter-rotating rollers are held by a second bracket mounted in a fixed manner on the second common frame, with the second extruder being axially movable with respect to the second bracket.

23. The installation according to claim 15, wherein one or both of the first and second extruders is or are movably mounted with respect to the frame, between a working position and a rest position.

24. The installation according to claim 15, wherein the reinforcing-thread feeder includes a thread roller arranged to convey the reinforcing threads into the calender.

25. The installation according to claim 24, wherein the thread roller is translationally movable with respect to the calender.

26. The installation according to claim 15, further comprising a cutter structured to cut selvedges of the calendered reinforcing ply, the cutter being arranged adjacent the calender.

27. The installation according to claim 26, wherein the cutter includes a plurality of retractable arms that each bear a cutting wheel.

28. The installation according to claim 15, further comprising a controller that controls an automatic adjustment of a geometry of the calendered reinforcing ply.

Description

[0033] The invention will be understood better from studying the attached FIGS. 1 to 3, which are provided by way of examples and are in no way limiting, and in which:

[0034] FIG. 1 shows a schematic overview in cross section of a calendering installation according to the invention in a working position,

[0035] FIG. 2 is a front view of the calendering installation of the invention in a rest position,

[0036] FIG. 3 is a front view on a larger scale of the calender of the invention.

[0037] The calendering installation shown in FIG. 1 comprises a common frame 100 for supporting two extruders 200, 300, a reinforcing-thread feeding device 400 and a calender-forming device 500 in which the reinforcing ply 600 is produced.

[0038] The extruders 200, 300 each have a device 20, 30 for feeding an elastomer mixture which is worked in a barrel 21, 31, each comprising an extrusion screw provided to send the elastomer material into a flat die 22, 32. The extruder 200 has a frame 25 which is rigidly secured to the frame 100 with the aid of a flange 10 and a rod 11. The extruder 300 has a frame 35 which is mounted so as to be movable with respect to the frame 100 between a first working position and a second rest position. More particularly, the frame 35 is mounted so as to be able to pivot under the action of an electric actuating cylinder 14 about a horizontal axis 13, situated in a plane parallel to that of the reinforcing ply 600, and supported within a securing flange 12. This makes it possible to free the ply or the reinforcing threads during the preparation of the calendering operation or at the end thereof, in order to carry out cleaning.

[0039] The barrel 21, 31 of each extruder encloses a screw that is driven in rotation by a geared motor which is powered via the power cables 82, 83.

[0040] The calender 500 comprises a first pair of rollers 51, 52 which rotate in opposite directions, one with respect to the other, about mutually parallel axes that are perpendicular to the axis X-X, and define a first nip 55 between one another, and a second pair of rollers 53, 54 which rotate in opposite directions about mutually parallel axes that are perpendicular to the axis Y-Y and define a second nip 56 between one another. The rollers 51, 52 each have their own drive and are arranged so as to be movable with respect to one another on a bracket 26, in a direction perpendicular to the axis X-X, such that it is possible to adjust the nip 55. Similarly, the rollers 53, 54 each have their own drive and are arranged so as to be movable on a bracket 36, in a direction perpendicular to the axis Y-Y, such that it is possible to adjust the nip 56 that they define. The elastomer material which is output by the extruder 200 directly into the first nip 55 between two rollers 51, 52, comprising a first working roller 52 and a shaping roller 51, forms a first rubber ply 57. The elastomer material which is output by the extruder 300 directly into the nip 56 between the rollers 53, 54, comprising a working roller 53 and a shaping roller 54, forms a second rubber ply 58.

[0041] Advantageously, each extruder 200, 300 outputs the elastomer mixture into the nip formed by each pair of rollers 51, 52 and 53, 54, respectively, at a pressure greater than atmospheric pressure. By way of example, the pressure at the outlet of the extruders is between 10 and 70 bar. Thus, each nip 55, 56 is fed under pressure, making it possible to distribute the mixture uniformly over the width of the ply and to be able to precisely control the thickness of the ply 57 or 58, respectively. The rollers 51, 52, 53, 54 have a small diameter, less than 250 mm, making it possible to apply the nozzle of the output die of the extruder in a sealed manner close to the nip. Furthermore, the shape and size of the arch of the extruder 200, 300 are designed so as to balance the pressures and the flows exiting the extruder over the width of the ply. For example, the cross section of the arch of the extruder is flattened at the centre and widened at its edges in order to achieve the desired effect.

[0042] The range of adjustment of the nip 55 and 56 is for example between 0.2 and 4 mm. Each nip 55, 56 is adjustable independently, for example using an electric actuating cylinder which moves one of the two rollers of the nip with respect to the other. Thus, one of the rollers, for example the working roller 52 or 53, respectively, is mounted, with its drive, on a bracket moved by the rod of an electric actuating cylinder in the direction of the shaping roller 51, 54. The movable roller is moved from a first position, in which the two rollers 51, 52 or 53, 54, respectively, are in contact, this position being detected for example by measuring the intensity of the current absorbed by the motor for driving the movable roller in rotation, to a second position, which corresponds to the value of the calendering nip and is obtained by moving the rod of the electric actuating cylinder for actuating the movable roller. This makes it possible to produce rubber plies 57, 58 of variable and very precise thickness, it being possible for the thickness of one ply 57 to be the same as or different from that of the other ply 58.

[0043] A calendering nip 59 is formed between the working rollers 52 and 53. The value of the calendering nip 59 is established such that the rubber plies 57, 58 are pressed against one another in order to produce rubber bridges through the reinforcing threads 45 and thus to form the reinforcing ply 600. The nip 59 is adjustable depending on the force which needs to be applied to the reinforcing ply by the rollers. This force is measured by a strain gauge arranged between the end of the rod of the actuating cylinder 14 and the frame 36 and the position of the rod of the actuating cylinder 14 is adjusted as a consequence.

[0044] In the example illustrated in the figures, the bracket 26 is secured rigidly to the frame 25 of the extruder 200 and supports the flat die 22 and the two adjacent rollers 51, 52. The same goes for the bracket 36, which is secured rigidly to the frame 35 of the extruder 300 in order to support the flat die 32 and the adjacent rollers 53, 54. Each extruder 200, 300 can be moved axially (i.e. along its longitudinal axis) with respect to its die and to the adjacent rollers for cleaning purposes.

[0045] The reinforcing-thread feeding device 400 comprises a bracket 40 which receives the reinforcing threads that arrive from a plurality of spools (not illustrated in the drawings) in the form of a plurality of mutually parallel threads, which are arranged in a horizontal plane, and directs them to a first roller 41 for guiding the reinforcing threads 45, which is grooved. The roller 41 has a plurality of circumferential grooves or slots that are spaced apart from one another by one and the same spacing in the axial direction of the roller and are each intended to accommodate a reinforcing thread. The reinforcing threads 45 are conveyed into the vicinity of the calendering nip 59 by a second thread-laying roller 42 which, for its part, is smooth and inclined slightly in the direction of the calendering nip 59. The rollers 41 and 42 are arranged with their axes of symmetry mutually parallel and parallel to the axes of the calendering rollers 51, 52, 53 and 54. The roller 42 is disposed at a height greater than that of the calendering nip 59 and, as a result, the calendered ply having the reinforcing threads 45 is diverted by a first guide roller 61, which imparts an inclined trajectory thereon, the trajectory being tangent to the rollers 52 and 53 and passing through the calendering nip 59. The calendered ply 600 is then reoriented by a second guide roller 62 and by a third guide roller 63, it being moved between the rollers 62 and 63 in a plane P which is horizontal. The rollers 41 and 42 are movable in horizontal translation together with their bracket 40 with respect to the frame 100 between a working position and a rest position, as will be explained below. The guide rollers 61, 62 and 63 are mounted so as to be free to rotate about axes that are mutually parallel and parallel to the plane P.

[0046] A selvedge cutting device 700 is positioned close to the outlet of the calendering nip 59. The cutting device has a body 71 mounted in a fixed manner on the frame 100 and two parallel arms 72 that each bear, at one of their ends, a cutting wheel 70 arranged so as to rotate about a horizontal axis. The arms 72 are mounted so as to be able to move in the widthwise direction of the ply 600 with respect to one another so as to adjust them to the final width of the reinforcing ply 600. The arms 72 are also adjustable so as to be able to be moved towards and away from the reinforcing ply 600. By way of example, it is possible to adjust the width of the calendered ply between 5 and 200 mm with a precision of +/0.05 mm.

[0047] The calendering installation also comprises a command and control unit 800 connected to the various components of the installation, the operation of which it controls. The command and control unit 800 thus has computer means controlled by at least one computer program. This program comprises, in recorded form, code instructions that are able to control the implementation of calendering when it is run on a computer of the installation.

[0048] In operation, as is best visible in FIG. 1, the extruder 300 is arranged in the working position, its bracket 35 being brought into the high position by the actuating cylinder 14. The bracket 40 is pushed in the direction of the calender 500 such that the circumference of the second roller 42 is close to the nip 59 of the calender 500. More particularly, the roller 42 is pressed against the first ply 57 so as to come into contact therewith. Its position is advantageously adjusted automatically depending on the thickness of the first ply 57 by a pneumatic actuating cylinder (not illustrated). This actuating cylinder is arranged so as to move the bracket 40 depending on the pressure (measured with the aid of a strain gauge) that the roller 42 exerts on the roller 52. The extruders 200 and 300 are fed with strips of rubber via their feed orifices 20 and 30 and each die 22, 32 feeds the nip of the calendering rollers 51, 52 and 53, 54, respectively. The reinforcing threads 45 are coated with rubber coming from the rollers 52 and 53, passing through the calendering nip. The reinforcing ply obtained is driven in translation in order to exit the installation, by being oriented by the guide rollers 61, 62, 63, and is then wound up on a spool in a storage location (not illustrated in the drawings). In this way, a calendered ply of controlled thickness and width, which travels at high speed, is obtained, the speed being able to be adjusted up to 125 m/min.

[0049] FIG. 2 illustrates the calendering installation of the invention in the rest position, understood to be a position in which the various components have been moved with respect to their working position, for the purpose of cleaning or replacing the reinforcing threads, the elastomer mixture, or for the purpose of cleaning the extruders 200, 300 or replacing some of the components thereof (for example the extrusion screw or the die). In the rest position, the extruder 300 has been lowered by pivoting in the direction of the ground by actuation of the actuating cylinder 14 and is located at a distance from the extruder 200 and from the reinforcing-thread feeding device 400. The bracket 40 for the grooved roller 41 has also been moved away from the calender 500, as have the arms 72 of the cutting device 700. The operator can then replace the reinforcing threads 45, replace the elastomer mixtures by emptying each extruder 200, 300, and maintain or replace the various components of the installation.

[0050] The longitudinal axis X-X of the extruder 200 and the longitudinal axis Y-Y of the extruder 300 are inclined with respect to a horizontal plane P extending at the level of the guide rollers 62, 63 for the reinforcing ply 600 and each form an angle or , respectively, therewith. The angle or , respectively, is between 5 and 45 and is preferably around 15. In the example illustrated in the figures, the angles and are the same and the plane P forms a plane of symmetry for the arrangement of the extruders 200 and 300 in the working position. In one variant, the angles and are not the same as one another.

[0051] Advantageously, the horizontal plane P is situated at a distance of between 800 and 1400 mm from the base of the frame 100. The frame 100 of the installation is generally positioned on the ground, meaning that the components of the installation in which an operator needs to intervene are all located within his reach. Thus, he can fit the reinforcing threads 45 in the grooves of the grooved roller 41, feed the extruders with rubber via the feeding devices 20, 30, collect the rubber of the selvedges after cutting, or during the cleaning of the extruders, etc.

[0052] The calendering installation of the invention makes it possible to automatically adjust the thickness of rubber plies and the thickness of the reinforcing ply by controlling, via the command and control unit 800, the movement of the rollers 51, 52 or 53, 54 and that of the extruder 300. The width of the reinforcing ply 600 is also automatically adjustable, by adjusting the distance between the cutting wheels 70 of the cutting device 700. The calendering installation of the invention is thus readily adaptable and automatically adjustable.

[0053] This installation is also very compact, on account of the advantageous arrangement of its components, while having good ergonomics for the operator. Moreover, on account of its construction and given the flexibility of adjustment of its components, it makes it possible to obtain a very precise reinforcing ply, while making it possible to choose and adjust the dimensions thereof easily.

[0054] The calendering rollers 51, 52, 53, 54 are rigid and each have a diameter of around 250 mm. The diameter of the extruders is around 70 mm. Such an installation makes it possible to manufacture fairly narrow plies, with a width of between 5 and 300 mm with greater precision. Furthermore, on account of its reduced size and the ergonomic arrangement of the feeding extruders, the installation can be set up directly on the ground. Thus, the operator standing on the ground can easily and directly access the region of the calendering nip without it being necessary for the installation to be established in a pit, or to provide raised access for the operator, as in the majority of installations known from the prior art. Furthermore, the operator can easily access all of the intervention points from one side of the machine. Moreover, the various actuators used are electric, making it easier to install the installation in the workshop, for example by avoiding connections to a hydraulic or pneumatic network.

[0055] On account of the advantageous arrangement of its components and of the optimized dimensioning of the assembly, the calendering installation of the invention is able to fit in a container transported by a semi-trailer, its dimensions being less than those of the container.

[0056] Further variants and embodiments of the invention may be envisaged without departing from the scope of these claims. Thus, it is conceivable to arrange at least one of the extruders parallel to the plane P and the other inclined with respect thereto.