Plant for producing tyres of different types simultaneously

ES 2 249 463 T3 description

Installation for the simultaneous production of tires of different types.

The present invention relates to a plant and a method for manufacturing tires that are different from each other.

A tire for vehicle wheels normally comprises a carcass structure, essentially consisting of one or more carcass pleats formed in an essentially toroidal configuration and having their axially opposite side edges engaged with corresponding annular reinforcing structures incorporating inextensible inserts usually called " heel cables ”. Each annular reinforcing structure is incorporated into what is known as a "bead" formed along a circumferential inner edge of the tire to secure the tire to the corresponding mounting rim.

A waist structure, comprising one or more waist bands in the form of a closed loop, essentially consisting of textile or metal cords suitably oriented relative to the cords belonging to adjacent carcass pleats, is applied to the structure of housing in radially outer position.

A tread band, which normally consists of a band of elastomeric material of suitable thickness, is also applied to the belt structure in a radially external position.

It should be noted that, for the purposes of the present description, the term "elastomeric material" refers to the rubber mixture as a whole, in other words the complete material made up of at least one polymer base suitably amalgamated with reinforcing fillers, and / or process additives of various kinds.

A pair of sidewalls, each of which covers a lateral portion of the tire already between what is called a lateral area, located near the corresponding lateral edge of the tread, and the corresponding bead, is applied to the sides opposites of the tire.

Given the above, it should be noted that each type of tire is essentially distinguished from the others by a set of chemical and physical characteristics, structural, dimensions and appearance.

The chemical and physical characteristics essentially refer to the type and composition of the materials, and particularly to the recipes of the different mixtures used in the production of elastomeric materials. Structural characteristics essentially define the number and type of structural components present in the tire, and their location relative to each other in the tire structure. The characteristics of the dimensions refer to geometric measurements and the profile of the tire's cross-section (external diameter, chord or maximum width, height of the side wall and its radii, in other words the section radius) and will be indicated simply as "Specification" hereinafter. The appearance characteristics consist of the design of the tread surface, the ornamental patterns and the different writing pieces or distinctive signs reproduced on the tire, for example on the sidewalls of the tire, and will be indicated as a all as "tread pattern" throughout the remainder of the present description.

Conventional production processes essentially comprise four distinct stages in tire manufacturing:

a) preparation of the mixtures,

b) production of the individual structural components,

c) assembly of the different structural components in succession, to produce a green tire on a drum or other suitable support,

d) vulcanization of the green tire with simultaneous stamping of the tread pattern on the outer surface of the tire.

For the purposes of the present invention, "tire type" indicates a tire having a given specification, given structural components of which it consists, and given tread pattern.

In an effort to reduce production costs, technological development has been basically oriented towards the search for technical solutions that lead to the production of increasingly rapid and reliable machinery, in such a way as to minimize the time required to produce each tire, while maintaining or improving the quality of the finished product.

Therefore, plants with a high production capacity in terms of parts produced per unit of time have been produced, using tire manufacturing machinery that has reduced modification options (or in other words, is capable of producing only a limited range tire types), but which maximize serial production of tires that have identical structural characteristics. By way of example only, in the most up-to-date plants the output can be up to approximately two carcasses per minute, and the average output run in one month of operation for each item (type of tire) can be 3,200 pieces, with a 375 minute item change time.

Attempts have been made to reduce or eliminate the storage of semi-finished products present between one and the other of the aforementioned four process steps, in such a way as to minimize the costs and problems involved whenever the type of tire in production must be changed. For example, document EP 922561 proposes a method for controlling tire production, in which, to reduce or eliminate both the storage time of the green tire and the number of green tires that are stored, a complex unit is provided vulcanization, with a suitable number of modules to constantly absorb the output of the complex tire manufacturing unit. The production of tires of different types, particularly those that have different specifications, is achieved through the replacement and / or adaptation from time to time of the machinery provided in the complex tire manufacturing unit, in conjunction with the replacement of the tires. molds in the complex vulcanization unit.

The applicant has found that, in all cases, the production of the tires entails costs that increase with the variety of types of tires to be produced: in particular, it is necessary to intervene in the mixing process and / or production plants to enable component production

ES 2 249 463 T3 with different physical and chemical characteristics and / or in the production plants of the individual structural components to change the specification of the tires that are produced. It is also necessary to change the operating sequence (different mounting procedure) and / or the equipment and adjustment of the manufacturing machinery whenever a change is made in the structure and / or specification of the tire to be produced. Finally, it is necessary to have at least one vulcanization mold for each design specification pair of each different tread.

All of the above entails continuous costs for the purchase of molds with different specifications and different tread designs, and different equipment, costs to install the latter, output losses due to machine downtime (a process change or equipment generally causes machine downtime), and material waste. For example, in the case of continuous component production, downstream machine downtime and / or a change in component characteristics generates excess production that has to be rejected, because it is impossible to reuse.

Given these circumstances, in the applicant's perception the production of a large number of types of tires in a single plant is generally undesirable, particularly if the objective is to minimize costs. In fact, this objective is incompatible with a frequent change of equipment and production processes. When using production processes of the conventional type, the applicant has observed that, when the sales volume of each individual type is high enough, the number of the production plants can be multiplied in such a way as to make it possible to produce a different type. continuously on each floor, thus minimizing the aforementioned disadvantages. On the other hand, where the sales volume forecasts for specific types are not particularly high, for example on an annual basis, it is also possible in each case to carry out full production for at least one year immediately and continuously, for contain production costs for these types. This system can, however, affect the quality of the product sold, and tends to increase storage costs, because the products remain in reserve for a long period. The risk associated with sales also increases, for example as a result of unforeseen rapid obsolescence of the product, and there is an increase in the financial cost of capital tied to product reserves and the installation of molds that will be used only during the strict period required to complete production of the low forecast volume.

To tackle these problems, the applicant has already developed a production procedure in which each series of tires identical to others in terms of production is divided into daily batches, each comprising a quantity of tires sufficient to cover the daily output. of a mold. In this way the production of tires that have different specifications and / or different construction characteristics is optimized by eliminating the storage of large quantities of raw and vulcanized tires. This procedure is described in the European patent application EP 875364 in the name of the same applicant.

In a tire production plant, the tire vulcanization step is carried out in a period that is essentially identical for ranges of all types of tires, but on the other hand the tire manufacturing time differs considerably depending on the type of tire. tire to produce. Additionally, the application of even a single component has different lengths of time for different types of tire.

This prevents a frequent change of type within the plant described above, due to the creation of waiting times for the vulcanization stage each time a tire to be vulcanized belongs to a different type from the preceding one in the processing sequence of the raw tire.

On the other hand, a frequent change of tire type within a processing run also implies a frequent change of equipment to make the different types, thus increasing waiting times.

For the purposes of the present invention, the term "serial processing plant" denotes a plant in which the individual processing stages of the tire can be carried out in a fixed sequence, in other words in which each stage of processing of the tire tire starts immediately after the preceding stage has finished.

The applicant has observed that, in a serial processing plant, the total production time depends on the slowest processing stage.

For the purposes of the present invention, the term "critical process period" indicates a process period in which no changes in equipment are planned during the tire processing sequence.

The applicant has tried to solve the problem of controlling the functions of the plant in such a way as to produce, within a single critical period, types of tires that are different from each other, while minimizing the waiting times that are due. primarily to the difference in the rate of the green tire manufacturing steps between tires of different types.

According to the present invention, the applicant has provided a tire processing plant in which different types of tires can be produced within the same critical processing period without increasing waiting times.

More in particular, the Applicant has provided a plant for manufacturing green tires of different types by successively mounting elementary components on toroidal drums of predetermined dimensions. Therefore, once the number of tires to be produced for each type has been decided within a critical period, it is possible to determine a sequence for introducing the different drums into the plant and a sequence for various processing stages that makes it possible to maintain the average time to produce the quantity of green tires for this essentially constant critical period. In a plant of this class, the processing and the sequence of depositing the different components of the tabor are not the same for all types of tires, and, at the same time, they differ3

ES 2 249 463 T3 all types of tires are produced within the same critical period.

The tire is mounted in successive work stations, in each of which one of said elementary components is deposited on the drum.

The applicant provides a plant in which each work station is controlled by a local unit capable of recognizing the drum arriving at it, and consequently the type of tire to be produced. Each local unit communicates with a central unit of the plant that controls the passage of a drum from one work station to the next and distributes the control to the different work stations.

One aspect of the present invention refers to a plant for producing tires of different types simultaneously, comprising a plurality of operating units operating in succession, and characterized in that it comprises:

- a central processing unit capable of causing the sequential execution of a plurality of operational stages in the work stations, each of which comprises at least one of said operational units, according to one or more predetermined sequences of types of tires,

- a local processing unit associated with each work station and capable of identifying the type of tire corresponding to a drum provided for each of said operating units, and of selecting one of a predetermined group of operating procedures for each of said operating units which is specific to the type of tire corresponding to the drum being worked on.

In particular, each drum comprises a code that identifies the type of tire to be produced on it.

In particular, each work station comprises at least one reader of said code that identifies the type of tire.

Preferably, said identification code is associated with a shaft of said drum.

Preferably, said tire type identification code is a bar code.

Preferably, said reader of said identification code is associated with each operating unit.

Preferably, said reader of said identification code is associated with a robotic arm of each operating unit.

In a further aspect, the present invention refers to a method for manufacturing tires of different types in an automatic plant comprising a plurality of operating units that operate in succession, characterized in that it comprises the steps of:

- causing, in a central processing unit, the sequential execution of a plurality of operating steps in said operating units, according to one or more predetermined sequences of types of tires;

- identifying the type of tire corresponding to a tire provided to each of said operating units;

- selecting, from a predetermined group of operating procedures for each of said operating units, a specific procedure for the type of tire corresponding to the drum being worked on.

Preferably, said step of identifying the type of tire comprises reading an identification code of this type associated with the drum being worked on.

Additional features and advantages will become clearer from the following detailed description of the present invention, with reference to the accompanying figures, provided by way of example only and without limiting purpose.

Figure 1 shows a diagram of the plant according to the present invention.

Figure 2 schematically shows the stages of a tire production process according to the present invention.

Figure 3 schematically shows the connections between the units of the plant of figure 1.

Figure 1 shows an embodiment of a plant for manufacturing tires according to the present invention. The plant comprises a complex manufacturing unit 2 for the production of green tires, in which each tire that is processed is manufactured by assembling its structural components in a predetermined sequence, and a complex vulcanizing unit 3 in which each Tire arriving from complex manufacturing unit 2 is vulcanized within a corresponding mold 34, 35, 36, 37, 38, 39.

The complex manufacturing unit 2 comprises a plurality of workstations 5, 6, 7, 8, 9, 10 arranged consecutively along a processing path, preferably of the closed loop type, shown for orientation by arrows 11 on the attached figure 1. This line also has a feeding station 20, a temperature stabilization device 21, a first blocking station 22, a multiple blocking station 23, a second blocking station 24, a third blocking station 25 and a terminal station for lock 26.

The workstations 5,6,7,8,9,10 are capable of operating simultaneously, with each one operating on at least one tire in process, to mount at least one of its structural components on the tire.

More particularly, during the assembly stages, the different structural components used in the production of each tire are conveniently coupled to a support element, which preferably consists of a toroidal support or drum whose profile essentially reproduces the internal configuration of the tire to be produced. This toroidal support is made in such a way that it can be easily removed from the tire when processing is complete.

At least a first and a second type of tire can be treated simultaneously both in the complex manufacturing unit 2 and in the complex vulcanization unit 3. By way of example, in the following description, with reference to the arrangement shown in the attached figures 1 and 2, two different types of tires, differing from each other in their dimensional characteristics, are treated simultaneously. Clearly, it is also possible to operate simultaneously on a different number of types that may have, in addition to or as an alternative to dimensional differences, differences in terms of structural components and / or chemical and physical characteristics and / or appearance.

In the arrangement shown as a guide in the accompanying figures, the toroidal supports are shown without

ES 2 249 463 T3 distinguishes between them and the tires that are processed coupled on them, and are identified by the letters A and B, each of which indicates a specific type of tire.

As can be seen, the tires being processed are distributed along the line of the complex manufacturing unit 2 in such a way that the different types A and B follow each other in a preset sequence. Additionally, the preset sequence of tires to be produced within a critical period can be divided into a plurality of series having the same sequence of tires or having a different sequence, according to the types to be produced in each series. In the example shown in figure 1, a series comprising six tires, A, B, B, A, B, A, is distributed along a line of the production plant 1. In this example, a total of six toroidal supports, on each of which a corresponding tire is manufactured, are therefore operated simultaneously within the complex manufacturing unit 2.

It should be noted that, for the purposes of the present description, the term "series" indicates a set of tires of different types or of the same type, which follow each other in a predetermined sequence. In the complex manufacturing unit 2 it is possible to provide, for example, a plurality of series, each consisting of different types of tires, which advantageously follow each other in a cyclical way, for example, according to the pattern A, B, A , B, or series each of which may advantageously consist of a tire of the first type interposed between two tires of a second type, or series each of which consists of tires that are all of the same type, or various combinations of said sequences.

Devices for the functional transfer and movement of the tires operate in the plant to sequentially transfer each of the tires that are processed A and B from one of the work stations 5, 6, 7, 8, 9, 10 of the unit manufacturing complex 2 to the next, and to the complex vulcanization unit 3. Said devices also functionally move the toroidal support during the placement of at least one of said structural components.

This functional movement comprises a rotation of the toroidal support about its axis and a rotation and / or translation of this axis in space.

Preferably, these devices comprise one or more robotic arms R1, R2, R3, R4, R5, R6, R7 and R8, each of which is associated with at least one of the workstations 5, 6, 7, 8, 9, 10 and is capable of operating on the individual toroidal supports A or B, of carrying out the sequential transfer of each tire that is processed.

The tire is manufactured by moving the toroidal support and orienting it in space and applying the extruded structural components on top by both circumferential and axial deposition.

Said robotic arms advantageously support said toroidal supports in such a way that they project, in other words, holding them only on one side of the axis of rotation, thus allowing the various components to be deposited over the entire axial extension of the support having a curvature with two angles.

A processing unit directs transfers along said loop path and determines the number and composition of said series of tires within a desired critical period. This unit is capable of controlling said functional transfer and movement devices in such a way as to coordinate the processing steps on each type of tire in the complex manufacturing unit 2 and in the complex vulcanization unit 3.

More particularly, in the illustrated embodiment there is a first robotic arm R1, movable along a guide structure 19 if necessary, and operating between the complex manufacturing unit 2 and the complex vulcanizing unit 3, to pick up a finished tire of the latter and transfer it to the first work station 5, where the tire is extracted from the corresponding toroidal support by the robotic arm R8. The toroidal support A extracted from the tire is then transferred by the first robotic arm R1 of the first work station 5 into the temperature stabilization device 21.

If the tire to be produced requires the use of a toroidal support different from the one previously dismantled, the robotic arm R1 picks up the appropriate toroidal support from the feeding station 20 and inserts it into the temperature stabilization device 21.

This device 21 is capable of bringing the toroidal support up to a preferred temperature to allow subsequent processing, and particularly to promote adhesion of the first layer of elastomeric material to the metal of the support. This temperature is preferably in the range of 80 ° C to 90 ° C.

A second robotic arm R2 serves to transfer the toroidal support from the temperature stabilization device 21 to the second work station 6 where the first building components of the tire are mounted. The mounting operation may, for example, comprise coating the outer surface of the toroidal support A with a thin layer of an airtight elastomeric material, usually referred to as a coating, carried out by a coating processing unit 61, and the application of any elastomeric bands in the areas corresponding to the bead of the tire, carried out by the band processing unit 62, and / or the formation of an additional coating layer made of elastomeric material and placed on top of the coating, carried out by the sub-coating processing unit 63.

Preferably, at the second work station 6, and also at the remaining work stations 7, 8, 9, 10, the formation of each structural component of the tire is carried out in conjunction with the previously described assembly step, by processing of at least one semi-finished basic product that is identical to each type of tire A or B and provided in a predetermined quantity according to the type of tire to be built.

In particular, in the second work station 6 the production of the liner, the elastomeric bands and / or the additional lining layer can advantageously be carried out by winding at least one band-shaped element made of elastomeric material on the support toroidal A that

ES 2 249 463 T3 is processed, in consecutively adjacent turns and if necessary also at least partially superimposed, this element having a width of, for example, in the range of 0.5 to 3 cm, and being extracted directly from the corresponding extruder , from a spool or from other suitable feeding devices associated with the second workstation 6.

The winding of the turns can be significantly simplified by giving the robotic arm R2 the function of holding the toroidal support A, by means of suitable clamping and driving elements, and making it rotate on its own axis, thus moving it appropriately in front of pressure rollers or application devices. equivalent (not described) combined with power devices, in such a way to produce a correct distribution of the band element with respect to the outer surface of the toroidal support.

When the assembly of the components in the second work station 6 is completed, the second robotic arm R2 deposits the toroidal support, with the corresponding tire under construction, in the first clamping station 22. A third robotic arm R3 takes the toroidal support from the first clamping station 22 to transfer it to the third work station 7, where the structural components that contribute to the formation of the carcass structure of the tire are mounted.

More particularly, in the third work station 7 one or more carcass pleats are produced and mounted, together with a pair of reinforcing ring structures in the areas corresponding to the bead of the tire. In a similar way to that described with reference to the operational steps carried out in the second work station 6, each of said structural components is produced directly in the assembly step, using a semi-finished basic product provided in a predetermined quantity according to the type of tire being processed.

For example, the carcass pleat or pleats can be formed by sequentially depositing on the toroidal support a plurality of strip pieces, individually cut from a continuous strip element formed by a strip of rubberized cords placed parallel to one another. In turn, each annular reinforcing structure may comprise a circumferentially inextensible insert consisting, for example, of at least one metal cable element wound in a plurality of radially overlapping turns, together with a filler insert of elastomeric material that may made by applying an elongated elastomeric element wound in a plurality of axially adjacent and / or radially overlapping turns.

Each of said continuous band elements, the metal cable element and the elongated elastomeric element that form the semi-finished basic product to be used in a predetermined quantity to produce the corresponding structural component, can be taken directly from an extruder, from a spool or from other suitable feed devices associated with the third workstation 7.

For further explanations of the procedure for producing the carcass structure, reference should be made to European Patent Application EP

0976535 in the name of the present applicant.

In the arrangement shown in the attached figure, the third work station 7 is designed to produce casing structures such as those described in the European patent application EP 1133389, also in the name of the present applicant. The carcass structure described in this patent application comprises two carcass pleats, each consisting of a first and a second series of band pieces deposited in an alternating sequence on the toroidal support. A pair of reinforcing structures of the type previously described is also provided in each bead of the tire, each of these structures being inserted between the terminal fins of the pieces, belonging to the first and second series respectively, and forming one of the pleats of carcass, together with an inextensible insert applied externally relative to the second carcass ply.

To facilitate the sequential assembly of the different structural components in the predetermined order, the third work station 7 is equipped with at least three work stations respectively designed for the deposition of the strip pieces (unit 17) of the metal cable element (unit 72), and of the elongated elastomeric element (unit 73), which operates simultaneously, each on the corresponding tire being processed. Subsequently, three tires, even if they are of different types from each other, can be treated simultaneously in the third work station 7, each of the tires being transferred sequentially from one of the processing units to another until they have been processed. completed the carcass structure. The sequential transfer of the tires in the different processing units provided in the third station 7 can be carried out by means of the third robotic arm R3, aided if necessary by a fourth robotic arm R4 and / or by any necessary auxiliary transfer device or by the multiple support station 23, in which more than one toroidal support may be present at the same time. This system makes it possible to minimize waiting periods when the tires that are processed in this work station are of types that differ from each other; this is because it is possible to use the multiple support station 23 to perform the processing on types that require a longer time at the most favorable moment, advantageously altering the order of the arrival sequence of the toroidal supports at the work station. In the attached figure 1, the unit 71 for depositing the carcass ply is coupled with a type B tire and the unit 72 for depositing the bead wires is coupled with a type A tire.

Upon completion of the carcass structure, the fourth robotic arm R4 deposits the toroidal support on the second support station 24.

The fifth robotic arm R5 picks up the toroidal support from the second support station 24, to take it to the fourth work station 8, which in the example shown is occupied by a toroidal support of type A. In the fourth work station 8, the structural components that serve to form what is known as the tire belt structure are produced and assembled. In particular, a first processing unit 81 provided in the fourth work station 8 deposits, directly on the previously formed carcass structure, two ban6

ES 2 249 463 T3 under the waistband extending circumferentially in the lateral areas of the tire. The belts under the waist can be extruded directly from an extruder and applied with the aid of pressure rollers or equivalent application devices. A second processing unit 82 forms first and second waist bands on the carcass structure, each band being formed by sequential deposition of band pieces positioned adjacent to each other in a circumferential manner, each piece being made by cutting to a size. of a continuous band element consisting of a plurality of cords adjacent and parallel to each other and incorporated in an elastomeric layer. Another processing unit 83 forms another waistband by winding a continuous cord in turns that are axially adjacent to each other and radially superimposed on the underlying waist layers. Other details of a possible method for producing the waist structure are described in European Patent Application EP 0943421, in the name of the present Applicant.

When the belt structure is completed, the sixth robotic arm R6 transfers the tire to be processed to the fifth work station 9. In the fifth work station 9, the toroidal support B is engaged by the robotic arm R6 with the help of which a tread band is applied, this tread being produced by winding at least one additional elastomeric band element on consecutively adjacent and radially overlapping turns until a tread having the desired configuration and thickness is obtained. In the example shown, the operation is carried out by two units 91 and 92. When said operations have been completed, the sixth robotic arm R6 deposits the toroidal support on the third support station 25.

The tire is then transferred to the sixth work station 10, occupied by a type A tire in the example shown. In the sixth work station 10, the toroidal support is coupled by means of a seventh robotic arm R7 that makes it move appropriately in front of the corresponding processing units to perform the application of abrasion resistant elements to the areas corresponding to the heels ( unit 101), and the application of the flanks, which are also produced by winding at least one elastomeric band in adjacent and / or overlapping turns (unit 102).

When this operation is finished, the seventh robotic arm R7 deposits the manufactured tire on the terminal support station 26, where the tire is supported until it is transferred to the complex vulcanization unit 3.

Each of the workstations 5, 6, 7, 8, 9, 10 not only has one or more processing units, but also comprises a feeding device to supply the basic elements required for the production of the corresponding structural element, operating in conjunction with the application devices present in the aforementioned units, which apply the basic element and / or the resulting structural component to the tire being processed.

The complex vulcanization unit 3 advantageously comprises at least one set of vulcanization molds 34, 35, 36, 37, 38, 39, the number of which is equal to the number of tires included in said series of tires that are processed in the unit. complex manufacturing 2. In the example shown, six vulcanization molds 34, 35, 36, 37, 38, 39 are provided, each corresponding to the specification of one of the types of tire that are manufactured along the line of the tire unit. complex manufacturing

2.

Preferably, the molds 34, 35, 36, 37, 38, 39 are mounted on a turntable 30 that can be rotated with a stepwise motion, such that the molds are made to follow a path, within the complex vulcanization unit 3, to provide them sequentially one after the other, then to a loading and unloading station 40 for the tires to be processed. This rotation is preferably carried out with a first rotation in a first direction of rotation, followed by a rotation in the direction opposite to the first. Alternatively, this rotation can be of the closed loop type.

Each of the molds 34, 35, 36, 37, 38, 39 is supplied with pressurized steam through a corresponding connection line (not shown) extending radially from a central column in which steam supply devices , consisting of a boiler for example, are integrated or connected in another way. The entire turntable 30 may advantageously be enclosed in an insulated structure having at least one access opening located downstream of the loading and unloading station 40, to avoid excessive heat dissipation to the outside.

Advantageously, the transfer of the individual tire that is processed in the corresponding molds 34, 35, 36, 37, 38, 39 is carried out by the robotic arm R1 with an index equal to the completion index of the tires that are processed in the stations of work distributed along the complex manufacturing unit line 2.

The plant described by way of example operates in the following stages, shown schematically in figure 2 and associated with the movements of the robotic arms R1, R2, R3, R4, R5, R6, R7 and R8. In the figure, and in the rest of the present description, the stages identified by the letter T followed by a progressive number refer to the manufacture of a green tire, and the stages identified by the letter C followed by a progressive number refer to to the vulcanization of the tire and to the disassembly of the toroidal support.

T1) The robotic arm R1 picks up a toroidal support, called the "core" below, from the feed station 20, and inserts it into the temperature stabilization device 21.

T2) The core is extracted from the device 21 by the robotic arm R2 and placed in front of an extrusion head of the unit 61. The arm R2 rotates the core in such a way that the extruder deposits a band of elastomeric material on the surface of the core.

T3) Robot arm R2 positions the core in front of an extrusion head of unit 62. Arm R2 rotates the core such that the extruder deposits a band of elastomeric material on the specified portion of the core surface.

T4) (optional) The robotic arm R2 places the core in front of an extrusion head of the unit 63.

ES 2 249 463 T3

Arm R2 rotates the core in such a way that the extruder deposits a band of elastomeric material near the heels of the core.

T5) The core is deposited by the robotic arm R2 in the first support station 22.

T6) The robotic arm R3 picks up the core from the first support station 22 and inserts it into the carcass fabric deposition unit 71, in which a first layer of carcass fabric pieces is deposited.

T7) The robotic arm R3 picks up the core from the carcass fabric deposition unit 71 and inserts it into the bead wire deposition unit 72, inside which a pair of annular reinforcing structures are deposited on the core in the areas corresponding to the beads of the tire.

T8) The robotic arm R3 picks up the core from the bead wire deposition unit 72 and deposits it in one of the positions of the multiple support station 23.

T9) The robotic arm R4 picks up the core from the support position 23 and places it in front of an extrusion head of the elastomeric filler deposition unit 73. The arm R4 rotates the core in such a way that the extruder applies a band of elastomeric material on the beads of the tire being processed.

The above steps can be repeated a plurality of times, depending on the type of tire that is produced. For this purpose, the multiple support station 23 is provided, which has multiple positions, each capable of supporting a core, together with two robotic arms R3 and R4 to produce the carcass structure.

T10) The robotic arm R4 deposits the core in the second support position 24.

T11) The robotic arm R5 picks up the core from the second support position 24 and places it in front of an extrusion head of the belt deposition unit under the waist 81. The arm R5 rotates the core in such a way that the extruder deposits a band of elastomeric material on the lateral areas of the tire.

T12) The R5 robotic arm inserts the core into the 82 waistband deposition unit.

T13) The robotic arm R5 picks up the core from unit 82 and inserts it into processing unit 83, which forms another waist layer by winding a continuous rope in turns axially adjacent to each other and radially superimposed on the waist layers underlying.

T14) The robotic arm R5 deposits the core back in the second support position 24.

T15) The robotic arm R6 picks up the core from the second support position 24 and places it in front of an extrusion head of the band deposition unit under the tread band 91. The arm R6 rotates the core in such a way that the extruder deposits a band of elastomeric material on the crown area of ​​the tire being processed.

T16) The robotic arm R6 places the core in front of an extrusion head of the tread deposition unit 92. The arm R6 rotates the core in such a way that the extruder deposits a band of elastomeric material on the area of ​​the crown of the tire being processed.

T17) The robotic arm R6 deposits the core in the third support station 25.

T18) The robotic arm R7 picks up the core from the third support station 25 and places it in front of an extrusion head of the deposition unit of the abrasion resistant layer 101. The arm R7 rotates the core in such a way that the The extruder deposits a band of elastomeric material on the beads of the tire being processed.

T19) The robotic arm R7 places the core in front of an extrusion head of the sidewall deposition unit 102. The arm R7 rotates the core in such a way that the extruder deposits a band of elastomeric material on the sides of the tire that is processes.

T20) The R7 robotic arm deposits the core on the terminal support station 26.

The green tire is now complete; the later stages are related to the vulcanization of the tire and its removal from the core.

C1) The robotic arm R1 picks up the core, with the green tire manufactured on it, and transfers it to the complex vulcanization unit, and in particular to an empty vulcanization mold 39.

C2) The vulcanizer closes the mold and rotates one position. The tire is vulcanized within the period of one complete rotation of the vulcanizing apparatus. At the end of each stage of this rotation, each of the other molds is loaded with a green tire to be vulcanized.

C3) The first robotic arm R1 picks up the vulcanized tire, together with the corresponding toroidal support, from the mold 39, and deposits it in the first manufacturing station 5, in a station 16 to disassemble the toroidal support.

C4) The eighth R8 robotic arm removes the toroidal support and deposits it in a recovery station 28.

C5) The eighth robotic arm R8 picks up the vulcanized tire and deposits it on a storage platform 14, where tires previously produced by the plant can be placed while they wait to be sent to the subsequent finishing and inspection stages.

The process for the treatment of the individual tires along the line of the complex manufacturing unit 2 is such that the deposition of a structural component can be advantageously carried out independently of the completion of the production of another component on the tire. immediately earlier in the production process. A characteristic of the invention is that the structural components of the tire are essentially prepared at the time of their deposition, thus making it possible to operate without previously stored semi-finished products, and to adapt each unit immediately to the type of tire being processed, thus avoiding the expense of material.

Furthermore, the operation of each of the processing units in the individual workstations 5, 6, 7, 8, 9, 10, and that of each of the robotic arms, is controlled by a programmable local processing unit, such that the quantity of semi-finished commodities supplied is properly controlled, along with the movement imparted to the toroidal support, to ensure that the individual structural components of the tires being processed are formed correctly. In particular, this local processing unit can be programmed in such a way as to adapt the

ES 2 249 463 T3 operation of the robotic arm processing units to the type of tire being treated each time at each individual work station.

Furthermore, to impart greater operational flexibility to the plant, without limiting predetermined sequences of different types of tires, it is preferably envisaged to associate each of the workstations 5, 6, 7, 8, 9, 10 with devices to identify the type of tire being processed, interacting with selection devices to determine the amount of basic element to use to produce each structural component at the work station in question. For example, these identification devices may advantageously comprise a barcode reader or other types of codes associated with the toroidal support of the tire, which can be identified, by suitable reader devices, by the local processing unit, for the purpose of select the quantity of semi-finished product, for example using predetermined tables of values.

The moment a tire is transferred to any of the workstations 5, 6, 7, 8, 9, 10, the barcode reader identifies the type to which the tire belongs, allowing the processing unit to local adjust the operating program of the workstation in a suitable way, in addition to or as an alternative to the instructions received from the central unit.

In particular, Figure 3 shows an arrangement in which the communications between the central unit 111 and the local processing units 106, 107 and 108 associated with each of the workstations 6, 7 and 8 are clearly seen. This figure shows only three work stations, particularly the second work station 6, the third work station 7 and the fourth work station 8, in which the liner layer, the carcass structure and the belt structure are applied. , respectively. A unit for producing semi-finished products 206 or 207 or 208, otherwise known as a feeding device for supplying the basic semi-finished product to be placed on the drum, is shown at each station. In particular, in the second work station 106 this unit 206 produces the elongated elastomeric element; in the third work station 107 this unit 207 produces the continuous band element formed, for example, from a band of rubberized cords parallel to each other; and in the third station 108 this unit 208 produces the continuous belt element, consisting for example of a plurality of cords adjacent and parallel to each other and incorporated in an elastomeric layer.

Each of the units for producing the semi-finished products 206 or 207 or 208 communicates with the respective local unit 106 or 107 or 108. The programs for placing the semi-finished products on the drum, corresponding to the types of tires that can be manufactured at the plant, they are loaded into each local drive associated with a workstation. A database 222 that can be interrogated by the central unit contains all the programs for the placement of the different components for the types of tires that can be manufactured in the plant. This database is updated whenever a new type is produced.

In particular, the programs comprise instructions for the robotic arms related to the movement of the drum and instructions for the units for producing the semi-finished products. These programs are made available, preferably when the plant is started, to local units according to the operations to be carried out.

The flow of operations is carried out as follows:

The central unit 111 receives a production request comprising the types to be produced and their measurements and quantity.

This unit prepares one or more series of tires to be produced in a continuous flow, and allows each work station, through communication with each local unit, to pick up a drum from a support station, in such a way that it remains the default sequence. The central unit also places the correct molds on the vulcanizing table to produce these types.

Each local unit recognizes the drum to be picked up by means of said identification means located on the drums, for example the barcode mentioned above. Recognition of the drum and therefore the type of tire to be produced enables the local unit to activate the correct program for the operation to be performed on the drum of the work station in question. At the end of the operation, each local unit sends a signal to the central unit which controls the flow of tires to be processed and which determines their progress from one work station to the next.

For example, said barcode can be placed on an axis of said drum. The robotic arm picks up the drum by gripping it through this shaft.

The devices for reading said barcode are preferably associated with each operating unit. Even more preferably, these devices for reading said barcode are associated with each workstation. In addition, these devices to read said bar code can be associated with each robotic arm present in each work station.

The movement of the tires to be processed is advantageously controlled in the form of a continuous flow in which the complex manufacturing unit 2 is directly connected to the complex vulcanization unit 3, the sequential transfer of the individual tires being carried out according to an index equal to completion rate of tires in complex manufacturing unit 2, thus advantageously eliminating the need to store green tires in storage accumulations provided between the complex manufacturing unit and the complex vulcanizing unit.

The possibility of changing the assembly sequence of the different structural components according to the type of green tire to be produced allows the average manufacturing time to coincide with the vulcanization time.

In the above description, the production of different types of tires, A and B, was covered by way of example. The first type A refers to a tire that has the specification 195/65 R15, with which it is known as a “plain cloth” carcass structure, and the type B refers to a tire that has the specification 215/45 R17, with which a "two-ply" carcass structure is known. Type A comprises a single layer of carcass fabrics, while

ES 2 249 463 T3 that type B comprises a double layer of carcass ply. Due to the diversity of dimensions and, consequently, the different volumes of the two different types, the processes carried out on type B require a longer time than the processes carried out on type A. However, while the processes in the first, second, fourth and fifth workstations are compatible with the total cycle times, the process in the third workstation 7, in which the carcass structures are produced, is significantly different for the two types, particularly as it requires repeat deposition of a layer of carcass fabrics for type B.

If the processes carried out previously were carried out in succession, then it would be necessary to extend the cycle time by adapting it to the type that requires the longest times, or to provide an additional workstation.

However, the pair of robotic arms R3 and R4 and the multiple support station 23 are capable of changing the processing sequence.

For example, if the first tire to arrive at the third work station 7 is a type B tire, in other words the one that requires the longest processing time, the predetermined processing sequence is modified. This is possible by the fact that some processes require a time shorter than the rate required to keep the complex vulcanizing unit always fed with a tire for each rotation of the turntable 30. Thus, it is possible to recover useful time to make the change in the sequence.

The processing time in each processing unit and the transfer rate are determined according to the number of movement stages required along the line of the complex vulcanizing unit 3, such that each tire A, B can remain in the complex vulcanization unit for a time at least sufficient to complete the vulcanization process.

For example, in the production station of the carcass structure (third work station) type A requires a minimum processing time of approximately 1.5 minutes, and type B requires a minimum processing time of approximately 3 minutes, due to the fact that this type requires a double application of the carcass fabrics, as described above.

At work stations applying the coating and sub-coating (second work station), the belt frame (fourth work station), sidewalls and abrasion resistant belt (sixth work station), the time Processing time (minimum) is less than 2.5 minutes for both types A and B. The work station applying the tread (fifth work station) requires a processing time (minimum) of approximately 2.5 minutes for both types A and B.

The complex vulcanization unit 3 has six vulcanization molds; To perform vulcanization under the chosen conditions, each mold is required to remain in the vulcanizer for 15 minutes. To achieve this vulcanization time while the rotary support of the vulcanizer performs six stages of rotation, a tire has to be supplied to the complex vulcanization unit once every 15: 6 = 2.5 minutes.

According to the data provided above, this time is compatible with the times of stations 6, 8, 9 and 10, while the third work station 7 is critical, since type B requires a processing time that here is too long for the desired index.

To allow the third stage to be carried out, a plurality of series of types are provided that are initially fed to the complex manufacturing unit.

Each series consists of a plurality of tires equal to the number of vulcanization molds.

Each series consists of three type A tires and three type B tires, according to a first order, defined as follows: A1 B1 B2 A2 B3 A3 (the numbers 1, 2, 3, etc. associated with each type A, B in the sequence identify the succession in time of the different types of tires supplied in the sequence).

After the application of the coating and the sub-coating (second work station) the order in each series remains unchanged.

On the third workstation, the processing sequence requires, for example, the execution of the following consecutive steps:

1. production of the single carcass fabric on A1; A1 continues to the next lock stations^jo;

two. production of the first carcass fabric on B1; B1 is put on hold at multiple support station 23;

3. production of the first carcass fabric on B2; B2 is put on hold at the multiple support station 23 (in a different position from that occupied by B1);

Four. production of the second carcass fabric on B1; b1 continues to the next workstations;

5. production of the simple carcass fabric on A2; A2 continues to the next workstations;

6. production of the second carcass fabric on B2; B2 continues to the next workstations;

7. production of the first carcass fabric on B3; B3 is put on hold at multiple support station 23;

8. production of the simple carcass fabric on A3; A3 continues to the following workstations;

9. production of the second carcass fabric on B3; B3 continues to the next workstations.

After the third work station, the series has a second order, as follows: A1 B1 A2 B2 A3 B3; this second order is different from the initial order. The number of stages carried out is nine; each stage requires a processing time of 1.5 minutes, and therefore the total time for which the workstation is occupied applying the carcass structure on all six tires is 1.5 x 9 = 13.5 minutes . The total time is less than 15 minutes, which represents the desired rate for the vulcanization of the six tires.

As a result of the predetermined order of the series, along with the steps performed in the third work station as described above, the time for the production of the carcass structure on type B is no longer critical.

In this example, the order is not changed any more on the following workstations, and the 2.5 minute rate is maintained on all subsequent workstations.

ES 2 249 463 T3 nes, since they require a processing time that is less than or equal to 2.5 minutes.

Furthermore, type A1 is ready for the next station after 1.5 minutes, while another 4.5 minutes pass between it and the next type B1.

In the following processes, type A1 can be slowed down by about 1 minute, while type B1 processing has to be sped up by 1 minute. The slowdown is done by the support station 23, or by slowing down the application rate of one or more of the downstream components.

The acceleration of the B1 type is achieved by performing the following processing in the minimum time, particularly by performing the deposition operations of the belt structure and the flanks in 2 minutes each.

The vulcanization molds are placed according to the second order, in other words in the sequence A1 B1 A2 B2 A3 B3, such that type A is received when a vulcanization mold is provided for this type.

The series follow each other along the manufacturing and vulcanization lines until the end of the critical period, at which point the molds can be replaced if different types are to be produced in the next critical period.

With the procedure described above, within a critical period of, for example, eight hours, 96 type A tires and 96 type B tires are produced.

In view of the above, for two types, such as A and B, it is necessary to specify a series in which one type B is followed by at least one type A, so that the sum of the times for the processing of type A tires by means of a predetermined work station (for example the one in which B undergoes the same process at least twice) until the end of the manufacture of the tire in Crude oil is shorter than the average total time of said processes by a time that corresponds to the time difference between types A and B in said predetermined stage.

This makes it possible to perform the processing step that requires the longest time without causing a delay in the execution of the following steps.

A change in the order of the series in the third work station 7 that forms the carcass structure has been described above; The present invention is also applicable to types of tires that also differ from each other in the deposition of other components, for example belt structures. In this case, the sequence will also be modified at the fourth workstation 8, providing an additional multi-support station.

More generally, depending on the position of the critical stage in the processing sequence, the stages will be sped up or the waiting times between the stages before or after said critical stage will be shortened, such that the excess time introduced is compensated by the critical stage.

If necessary, a special support station can be provided.

In the plant according to the present invention, predetermined series and modifications of the order of each series are made possible by functional transfer and movement devices, particularly robotic arms, which allow the processing steps to be dissociated from each other. This is because a change in the order of the series means that one type of tire follows a different processing path than another type. The functional transfer and movement devices make it possible, within a single critical operating period, to use a plurality of trajectories simultaneously, one for each type of tire being processed.

Each series represents a time package of stages organized in trajectories, each one corresponding to a type of tire produced. The path through the different processing stages determines the type of tire manufactured.

Furthermore, the numbers of said support stations, of said molds, and of said functional transfer and movement devices, may vary according to how many, and what types of tires are to be produced within a critical period, as well as in relation to the performance of used equipment.

If required, it is also possible to reduce the effective time of the vulcanization process carried out on the individual tires, for example by delaying the injection of steam into the mold 34, 35,36,37, 38, 39 after the tire is has been introduced inside it. Therefore, it is alternatively possible to set different effective vulcanization times for the different types of tires that are produced.

The present invention also makes it possible to eliminate or at least minimize downtime on each occasion when a type of tire that is produced is changed.

This is because, in these cases, the toroidal supports and the vulcanization mold suitable for the production of one type have to be replaced with toroidal supports and the vulcanization mold suitable for the production of the new type.

This replacement, which, however, is only required when dimensional characteristics and / or tread design are changed, can be done with minimal effect on production, providing the appropriate equipment if necessary.

Thus, the invention makes it possible to conveniently produce tires in very small batches, of a few units, without requiring significant increases in the unit cost of the tires.

It is also possible to produce batches of tires comprising tires that are all of different types from each other, without requiring changes to the equipment that produces the green tires.