FOR VEHICLE WHEELS^ND WORKING STATION THEREFOR

DESCRIPTION

The present invention relates to a method for controlling the application of noise reducing elements to tyres for vehicle wheels.

Typically, a tyre for vehicle wheels has a substantially toroidal structure about an axis of rotation thereof in operation, and has an axial middle plane orthogonal to the axis of rotation, said plane being typically a plane of (substantial) geometric symmetry - i.e. without considering some possible minor asymmetries due, for example, to the tread pattern and/or to writings on the sidewalls and/or on the inner structure.

The "inner cavity" is the space delimited by the inner surface of the tyre and by the surface of the mounting rim facing towards the inner surface of the tyre, when the latter is in the mounted condition.

The "inner circumferential development" is the linear development of the inner surface of the tyre in its axial middle plane.

The terms "radial" and "axial" and the expressions "radially inner/outer" and "axially inner/outer" are used herein to refer to a direction perpendicular and a direction parallel to the axis of rotation of the tyre, respectively.

The terms "circumferential" and "circumferentially" are instead used herein with reference to the direction of annular development of the tyre, i.e. the rolling direction of the same.

The expression "noise reducing element" refers to an element that, when applied to the inner surface of a tyre (typically to the inner surface portion corresponding to the tread band), has the ability to attenuate the noise generated during the rolling action because of the presence of the inner cavity (cavity noise). This ability of the aforementioned element is usually due to the type of material(s) employed for manufacturing said element and/or the dimensions of the same and/or the number of elements inserted in the cavity. Such noise reducing elements may consist of blocks, e.g. having a substantially parallelepiped shape, of porous material, e.g. polymeric foam material, which are glued to that portion of the inner surface of the tyre which corresponds to the tread band and are arranged sequentially, one after another, along the inner circumferential development of the tyre.

The term "digital image", or equivalently "image", generally refers to a data set, typically contained in a computer file, wherein each tuple of coordinates (typically each pair of coordinates) of a finite set (typically a bidimensional and matricial one, i.e. N rows x M columns) of tuples of spatial coordinates (each umpteen corresponding to one "pixel") is associated with a corresponding set of numerical values (which may be representative of different quantity types). For example, in monochromatic images (like grayscale ones) this set of values consists of a single value in a finite scale (typically with 256 levels or shades), such value being, for example, representative of the brightness (or intensity) level of the respective umpteen of spatial coordinates, when displayed . Another example is given by colour images, wherein the set of values represents the brightness level of a plurality of colours, or channels, which are typically the fundamental colours (e.g. red, green and blue in RGB coding, or cyan, magenta, yellow and black in CMYK coding). The term "image" does not necessarily imply the actual visualization thereof.

Any reference to a specific "digital image" includes, more generally, any digital image that may be obtained by subjecting said specific digital image to one or more digital processing steps (e.g. filtering, equalization, smoothing, binarization, thresholding, morphological transformations (opening, etc.), derivative or integral calculations, etc.).

Document WO2016/067192 Al, in the name of the same Applicant, describes a process and an apparatus for automatically applying a noise reducing element to a tyre for vehicle wheels. The noise reducing element is guided in a predetermined direction and, during said guiding action, an adhesive material is applied onto a first surface of the noise reducing element. In particular, the noise reducing element is disposed on a first conveyor belt movable along a feeding direction and having, on a top surface thereof, a continuous film supporting a layer of adhesive material. The noise reducing element is pressed against the first conveyor belt, so that it integrally adheres to a portion of said layer of adhesive material. Through the effect of the motion of the first conveyor belt along said feeding direction, the noise reducing element is transferred to a second conveyor belt arranged downstream of the first conveyor belt. During this transfer, the continuous film is held at the first conveyor belt and, as soon as the noise reducing element leaves the first conveyor belt, the portion of said layer of adhesive material that adheres to the noise reducing element is detached from the layer of adhesive material that is present on said first conveyor belt. The noise reducing element is then picked up by the second conveyor belt and positioned in a predetermined position on a radially inner surface of the tyre for vehicle wheels, bringing said first surface into contact with said radially inner surface.

Document EP 2 100 833 A1 describes a device for individual conveying of elongate articles. The device is provided with a video camera adapted to monitor transversal seatings as they transit, in order to detect, in each one of them, the presence or absence of elongate articles and, in the former case, the number, position and orientation thereof. The device is equipped with robotized manipulating members, serving said video camera, adapted to remove, from each one of the occupied transversal seats on arrival, at least one of said elongate articles, on the basis of the coordinates provided by the vision camera itself, in order to transfer the article to an output position downstream, with a predetermined orientation.

The Applicant has observed that, in order to effectively reduce said noise, it is appropriate to cover the radially inner surface of the tyre, almost throughout its extension, with noise reducing elements.

The Applicant has also observed that, still for the purpose of effectively reducing noise, it may be appropriate to employ noise reducers having different lengths in the circumferential direction. In particular, the Applicant has observed that, by using noise reducing elements of different length, it is possible to limit the generation of harmonics due to the presence of an excessively regular pattern, created by noise reducing elements all having substantially the same length.

The Applicant has also observed that these two arrangements require that the noise reducing elements be positioned on the radially inner surface of the tyre with particular precision and accuracy.

However, the Applicant has verified that, in a situation like the one described in WO 2016/067192 Al, the position of the noise reducing elements on the conveyor belt that is supporting them as they are picked up, e.g. by a robotized arm, to be applied to the radially inner surface of the tyre is essentially unpredictable a priori. In particular, the Applicant has verified that this is caused by the pulling action to which each noise reducing element is subjected when, jointly with the associated adhesive, it is separated from the contiguous noise reducing element, and also by the transverse movements/oscillations (which are small but not negligible) of the conveyor belt itself. The Applicant has thus verified that a robotized arm employed for picking up and applying the noise reducing elements in a situation like the one described in WO 2016/067192 Al, since it does not know the exact position of the noise reducing element on the conveyor belt, cannot pick it up in a precise manner and apply it to the tyre with the desired accuracy. This implies the risk, for example, of adjacent noise reducing elements overlapping each other, misalignment and/or wrong orientation of the noise reducing elements relative to the axial middle plane of the tyre. The Applicant has also verified that, once a noise reducing element has been incorrectly applied to a tyre, dedicated operations need to be carried out in order to remove such noise reducing element and clean the corresponding portion of the radially inner surface of the tyre. Such operations may be carried out manually by an operator, when action is taken with sufficient rapidity; otherwise, it will be necessary to employ specific equipment, e.g. machines using dry ice. At any rate, an incorrectly positioned noise reducing element will cause wasted time and resources.

The Applicant has perceived that, by improving the knowledge of the position wherefrom the noise reducing elements are picked up, e.g. by a robotized arm, it is possible to improve the precision of the positioning of the noise reducing elements themselves on the radially inner surface of the tyre.

As perceived by the Applicant, such a solution should also allow handling noise reducing elements having different dimensions, without adversely affecting the cycle time, i.e. the total time necessary for the application of all the noise reducing elements required by a given tyre.

The Applicant has then found that, by using an image detection system aimed at precisely detecting the noise reducing elements on the moving elements (e.g. conveyor belts, conveyors, etc.) that are carrying them to the respective pick-up zone/point for application to the inside of a tyre, it is possible to have such elements be picked up, e.g. by a robotized arm, with the desired accuracy and then positioned correctly on the radially inner surface of the tyre, in accordance with the design specifications.

According to a first aspect, the invention relates to a method for controlling the application of noise reducing elements to tyres for vehicle wheels.

Preferably, it is envisaged to feed a sequence of tyres to a working station.

Preferably, it is envisaged to feed to said working station, by means of a first conveyor, a first set of noise reducing elements.

Preferably, it is envisaged to activate a detection system in order to detect one or more first images.

Preferably, said one or more first images are representative of at least one noise reducing element of said first set.

Preferably, it is envisaged to activate a processor for determining first parameters.

Preferably, said first parameters are determined as a function of said first images.

Preferably, said first parameters are indicative of coordinates, in a first plane parallel to said first conveyor, of a point representative of said at least one noise reducing element of said first set.

Preferably, said first parameters are indicative of an angle of orientation of said at least one noise reducing element of said first set relative to a direction determined on said first plane.

Preferably, it is envisaged to send to a robotized arm, included in said working station, a first movement command.

Preferably, said first movement command is sent on the basis of said first parameters.

Preferably, said robotized arm is equipped with a terminal tool.

Preferably, said first movement command causes said robotized arm to position and orient said terminal tool in accordance with said first parameters, so as to couple said terminal tool to said at least one noise reducing element of said first set.

Preferably, said first movement command causes said robotized arm to pick up, from said first conveyor, said at least one noise reducing element of said first set.

Preferably, said first movement command causes said robotized arm to apply said at least one noise reducing element of said first set to the radially inner surface of a tyre of said sequence.

The Applicant believes that, in this manner, the application of the noise reducing elements to the radially inner surface of the tyre can be effected with the required precision, thereby attaining the desired performance in terms of noise reduction and avoiding the need for interventions for removing any incorrectly positioned noise reducing elements. In particular, the Applicant has verified that it is possible to keep the positioning errors below a threshold of approx one millimetre and the orientation errors below a threshold of approx. 0.1 degrees.

The Applicant also believes that this solution allows handling noise reducing elements having different dimensions, because the use of an image detection system makes it possible to work with different elements, even without particularly complex and sophisticated hardware/software structures.

Finally, the Applicant believes that this solution allows the cycle time to remain essentially unchanged, because the image acquisition and processing tasks take negligible times in comparison with the operations necessary for preparing, picking up and positioning the noise reducing elements.

According to another aspect, the invention relates to a working station for the application of noise reducing elements to tyres for vehicle wheels.

Preferably, a robotized arm is used.

Preferably, said robotized arm is configured for picking up noise reducing elements of a first set, supplied by a first conveyor.

Preferably, a detection system is used.

Preferably, said detection system is configured for detecting one or more first images.

Preferably, said one or more first images are representative of at least one noise reducing element of said first set.

Preferably, a processor is used.

Preferably, said processor is configured for determining first parameters.

Preferably, said first parameters are determined as a function of said first images.

Preferably, said first parameters are indicative of coordinates, in a first plane parallel to said first conveyor, of a point representative of said at least one noise reducing element of said first set.

Preferably, said first parameters are indicative of an angle of orientation of said noise reducing element of said first set relative to a direction determined on said first plane.

Preferably, said processor is configured for sending a first movement command to said robotized arm.

Preferably, said first movement command is sent on the basis of said first parameters.

Preferably, said first movement command causes said robotized arm to position and orient said terminal tool in accordance with said first parameters, so as to couple said terminal tool to said at least one noise reducing element of said first set.

Preferably, said first movement command causes said robotized arm to pick up, from said first conveyor, said at least one noise reducing element of said first set.

Preferably, said first movement command causes said robotized arm to apply said at least one noise reducing element of said first set to the radially inner surface of a tyre.

Under at least one of the above aspects, the present invention may have at least one of the following preferred features.

Preferably, the noise reducing elements of said first set are arranged in order on said first conveyor starting from a first initial noise reducing element.

Preferably, the first initial noise reducing element is the noise reducing element that precedes, in the advancing direction of said first conveyor, all the other noise reducing elements of the first set.

Preferably, said first images are representative of said first initial noise reducing element.

Preferably, said first parameters are associated with said first initial noise reducing element.

Preferably, upon receiving said first movement command, said robotized arm couples said terminal tool to said first initial noise reducing element.

Preferably, upon receiving said first movement command, said robotized arm applies said first initial noise reducing element to the radially inner surface of said tyre.

Preferably, it is envisaged to activate said processor for determining at least one first length of said at least one noise reducing element of said first set.

Preferably, said first length is determined on the basis of said first images.

Preferably, it is envisaged to activate said processor for making a first comparison between said first length and one or more first reference values.

Preferably, it is envisaged to activate said processor for selectively generating said first movement command as a function of said first comparison.

Preferably, the noise reducing elements of the first set substantially have a first dimension.

Preferably, the first dimension of the noise reducing elements of said first set is greater than or equal to 100 mm and/or smaller than or equal to 300 mm. Preferably, said first conveyor has a first terminal zone, wherefrom said at least one noise reducing element of said first set is picked up.

Preferably, it is envisaged to provide a contrast wall at said first terminal zone.

Preferably, it is envisaged to activate said processor for generating a discard signal to move said contrast wall and cause said at least one noise reducing element of said first set to be discarded.

Preferably, said discard signal will be generated if said first length does not match said one or more first reference values.

Preferably, it is envisaged to feed to said working station, by means of at least one second conveyor, at least one second set of noise reducing elements.

Preferably, it is envisaged to activate a detection system in order to detect one or more second images.

Preferably, said second images are representative of at least one noise reducing element of said second set.

Preferably, it is envisaged to activate said processor for determining second parameters.

Preferably, said second parameters are determined as a function of said second images.

Preferably, said second parameters are indicative of coordinates, in a second plane parallel to said second conveyor, of a point representative of said at least one noise reducing element of said second set.

Preferably, said second parameters are indicative of an angle of orientation of said at least one noise reducing element of said second set relative to a direction determined on said second plane.

Preferably, based on said second parameters, it is envisaged to send a second movement command to said robotized arm.

Preferably, said second movement command causes said robotized arm to position and orient said terminal tool in accordance with said second parameters, so as to couple said terminal tool to said at least one noise reducing element of said second set.

Preferably, said second movement command causes said robotized arm to pick up, from said second conveyor, said at least one noise reducing element of said second set.

Preferably, said second movement command causes said robotized arm to apply said at least one noise reducing element of said second set to the radially inner surface of said tyre.

Preferably, the noise reducing elements of said second set are arranged in order on said second conveyor starting from a second initial noise reducing element.

Preferably, the second initial noise reducing element is the noise reducing element that precedes, in the advancing direction of said second conveyor, all the other noise reducing elements of the second set.

Preferably, said second images are representative of said second initial noise reducing element.

Preferably, said second parameters are associated with said second initial noise reducing element.

Preferably, upon receiving said second movement command, said robotized arm couples said terminal tool to said second initial noise reducing element.

Preferably, upon receiving said second movement command, said robotized arm applies said second initial noise reducing element to the radially inner surface of said tyre.

Preferably, it is envisaged to activate said processor for determining, based on said second images, at least one second length of said at least one noise reducing element of said second set.

Preferably, it is envisaged to activate said processor for making a second comparison between said second length and one or more second reference values. Preferably, it is envisaged to activate said processor for selectively generating said second movement command as a function of said second comparison.

Preferably, the noise reducing elements of the second set substantially have a second dimension, different from said first dimension.

Preferably, the second dimension of the noise reducing elements of said second set is greater than or equal to 100 mm and/or smaller than or equal to 300 mm.

Preferably, a difference between the first dimension of the noise reducing elements of said first set and the second dimension of the noise reducing elements of said second set is greater than or equal to 10 mm and/or smaller than or equal to 80 mm.

Preferably, said second conveyor has a second terminal zone, wherefrom said at least one noise reducing element of said second set is picked up.

Preferably, said contrast wall is positioned at said second terminal zone.

Preferably, it is envisaged to activate said processor for generating a discard signal to move said contrast wall and cause said at least one noise reducing element of said second set to be discarded.

Preferably, said discard signal will be generated if said second length does not match said one or more second reference values.

Preferably, said processor is configured for determining at least one first length of said at least one noise reducing element of said first set.

Preferably, said processor is configured for making a first comparison between said first length and one or more first reference values.

Preferably, said processor is configured for selectively generating said first movement command as a function of said first comparison.

Preferably, said processor is configured for generating a discard signal to move said contrast wall and cause said at least one noise reducing element of said first set to be discarded.

Preferably, said robotized arm is configured for picking up noise reducing elements of a second set, supplied by a second conveyor.

Preferably, said detection system is configured for detecting one or more second images representative of at least one noise reducing element of said second set.

Preferably, said processor is configured for determining second parameters as a function of said second images.

Preferably, said processor is configured for sending to said robotized arm, based on said second parameters, a second movement command.

Preferably, said detection system comprises a first detection device configured for detecting said first images.

Preferably, said detection system comprises a second detection device configured for detecting said second images.

Preferably, said processor is configured for determining, based on said second images, at least one second length of said at least one noise reducing element of said second set.

Preferably, said processor is configured for making a second comparison between said second length and one or more second reference values.

Preferably, said processor is configured for selectively generating said second movement command as a function of said second comparison.

Preferably, said processor is configured for generating said discard signal to move said contrast wall and cause said at least one noise reducing element of said second set to be discarded.

Preferably, said robotized arm is an anthropomorphic robotized arm with at least six axes of rotation.

Further features and advantages will become more apparent in the light of the following detailed description of a preferred but non-limiting embodiment of the invention. Reference will be made in the following description to the annexed drawings, which are also provided by way of illustrative and non-limiting example, wherein:

- Figure 1 schematically shows, for descriptive purposes only, a sectional view (not in scale) along the axial middle plane of a tyre provided by a working station in accordance with the invention;

- Figure la shows one possible deformation profile of a noise reducing element applied to the inner surface of a tyre;

- Figure 2 shows a block diagram representing a schematic plan view of a working station in accordance with the present invention;

- Figure 3 shows a block diagram representing a schematic side view of the working station of Figure 1;

- Figure 4 schematically shows an element associated with the working station of Figures 2-3;

- Figure 5 schematically shows one possible embodiment of a part of the working station represented in Figure 2.

With reference to Figure 1, the tyre 100 has an axis of rotation Z and an inner circumferential development of the radially inner surface 3 in the axial middle plane.

A sequence of noise reducing elements 2, preferably having at least two different dimensions (circumferential lengths), is applied circumferentially onto the radially inner surface portion 3 of the tyre, preferably in a position corresponding to the tread band 4.

In the tyre shown by way of example in Figure 1, the sequence of noise reducing elements consists of nine elements, wherein five noise reducing elements 6 have a dimension LI greater than the dimension L2 of the remaining four noise reducing elements 7. Figure la shows one possible deformation profile of a noise reducing element 2, which is implemented, by way of example, as a right parallelepiped in its undeformed configuration (although other shapes are also possible, such as prisms, non-right parallelepipeds, etc.).

Each noise reducing element, when undeformed (continuous line), has a length L, a width (orthogonal to the plane of Figure la), and a thickness T.

When it is applied to the tyre (dashed line), the element 2 is subjected to a deformation to adapt its own shape to the curved inner surface of the tyre. The nature and extent of the deformation depends on one or more factors, such as the material and shape of the undeformed element 2, the curvature profile of the tyre, and the mode of deformation of the element.

It must be pointed out that, because of said deformation, the distance between two adjacent elements may change along the direction of the thickness of the elements (i.e. along the radial direction). For example, the lateral faces of the elements 2 applied to the tyre may converge towards the Z axis and get closer to each other (as shown in Figure 1), so that the distance between two adjacent elements measured at the radially inner faces 5 will be smaller than the distance measured at the radially inner surface 3.

In the present description, any reference to the length, width and thickness of an element 2 will relate to the element in the undeformed condition. Reference may however also be made, without departing from the present invention, to the deformed element. For example, it will be possible to consider either the circumferential length L' of the face in contact with the radially inner surface 3 of the tyre or the circumferential length L" at any point along the thickness, e.g. at half height (as shown in Figure la), or at the radially inner face 5.

Likewise, the inner circumferential development C as measured on the radially inner surface 3 (typically the radially inner surface of the liner) in the axial middle plane will be considered herein. It may however also be possible to consider, without departing from the present invention, other linear circumferential developments dependent on said inner circumferential development C. For example, with reference to Figure 1, one may consider the circumference of the circle enveloping the radially inner surfaces 5 of the elements 2.

Figures 2-3 schematically show a working station 1 in accordance with the invention.

The working station 1 comprises a robotized arm 50.

Preferably, the robotized arm 50 is an anthropomorphic robotized arm. More preferably, said robotized arm 50 is an anthropomorphic robotized arm with at least six axes of rotation.

Preferably, the robotized arm 50 is equipped with a terminal tool 51 (Fig. 5), which is positioned and oriented through movements of the robotized arm 50 itself.

By means of the terminal tool 51, the robotized arm 50 carries out the task of picking up noise reducing elements supplied to the working station 1 and applying the same to the radially inner surface of a sequence of tyres.

In one embodiment, the terminal tool 51 may have a plurality of suction channels (not shown) fluid-dynamically connected to a selectively operable suction device. Therefore, the gripping of the noise reducing elements and the holding thereof during the movements of the robotized arm 50 towards the tyre occur through the effect of the suction force exerted on the noise reducing elements when said suction device is activated. The noise reducing elements are released onto the radially inner surface of the tyre following the deactivation of said suction device.

Preferably, the terminal tool 51 comprises an engagement surface 52 having a curved profile. Preferably, the profile of the engagement surface 52 has a radius of curvature that is substantially the same as that of the radially inner surface 3 of the tyre 100 along the circumferential direction of the latter. In particular, the value of the radius of curvature of the engagement surface 52 is substantially equal to a mean value of the radii of curvature of the inner surfaces of a lot of tyres whereon the noise reducing elements have to be glued.

The sequence of tyres is fed to the working station by suitable feeding devices (not shown). For simplicity, Figure 2 shows only one tyre 100, to which the noise reducing elements are applied by the robotized arm 50.

Preferably, each noise reducing element comprises or is made of a soundproofing material, preferably a polymeric foam, preferably polyurethane foam, preferably of the open-cell type.

Preferably, the soundproofing material has a density in the range of approx. 5 kg/m ³ to approx. 60 kg/m ³ .

Preferably, each noise reducing element is a parallelepiped (typically, but not necessarily, a right one) having a length, a width and a thickness. Preferably, each noise reducing element has, in a plan view, a rectangular shape having said length and said width. For example, said length may be the major side of the rectangular shape. When in use, the thickness is disposed radially and the width is substantially disposed in the axial direction (not considering possible deformations of the element).

As will become clearer hereinafter, the noise reducing elements employed in the present invention are divided into at least a first set SI and a second set S2.

Preferably, all the noise reducing elements belonging to each set have the same three-dimensional shape and/or substantially the same length, the same width and the same thickness, thus facilitating the handling thereof.

Preferably, all the noise reducing elements of all sets have the same width and/or thickness. In other words, the noise reducing elements belonging to different sets differ only in the length value. In this manner, each sequence of noise reducing elements is substantially uniform throughout its development as far as the transversal dimension is concerned, thus preventing the rolling tyre from suffering from unbalancing problems and obtaining an even occupation of the cavity.

Preferably, all the noise reducing elements belonging to all sets have the same three-dimensional shape, thus facilitating the handling thereof.

Preferably, the length of all noise reducing elements is greater than or equal to 100 mm, more preferably greater than or equal to 150mm, and/or smaller than or equal to 300 mm, more preferably smaller than or equal to 250mm. Preferably, the width of all noise reducing elements is greater than or equal to 80 mm and/or smaller than or equal to 160 mm, more preferably smaller than or equal to 140 mm.

Preferably, the thickness of all noise reducing elements is greater than or equal to 10 mm and smaller than or equal to 50 mm.

Such noise reducing elements have good noise attenuation properties; they can be easily attached to the inner surface of the tyre by gluing by means of an adhesive; once glued, they will not deteriorate and will not detach when subjected to the deformation cycles undergone by the tyre rolling on the road; they will also keep the other performances of the tyre substantially unchanged.

Preferably, the noise reducing elements cover at least 80%, more preferably at least 90%, of the inner circumferential development of the tyre 100.

Preferably, the distance between two adjacent noise reducing elements, measured along the direction of inner circumferential development of the tyre 100, is comprised between 5mm and 20mm, in particular between 10mm and 15mm. A first conveyor 10 supplies a first set SI of noise reducing elements to the working station 1.

Each noise reducing element of the first set SI has substantially a first dimension LI. In practical terms, this means that all the noise reducing elements of the first set SI have a length substantially equal to the first dimension LI.

The term "substantially" referred to the dimensions of the noise reducing elements is meant to take into account production tolerances (due, for example, to the cutting operations) and/or manipulation tolerances (e.g. the adaptation to the curved inner surface). Said production and/or manipulation tolerances usually imply dimensional variations in the noise reducing elements not exceeding approx. ±3% of the nominal dimension. For example, for a circumferential dimension comprised between approx. 150 mm and approx. 250 mm, the tolerance may be, for example, approx. 1.5 mm.

A second conveyor 20 supplies a second set S2 of noise reducing elements to the working station 1.

Each noise reducing element of the second set S2 has substantially a second dimension L2. In practical terms, this means that all the noise reducing elements of the second set S2 have a length substantially equal to the second dimension L2.

Preferably, a difference between the first dimension LI and the second dimension L2 is greater than or equal to 10mm, more preferably greater than or equal to 20 mm, and/or smaller than or equal to 80 mm, more preferably smaller than or equal to 60mm.

The noise reducing elements of the first and second sets SI, S2 may be disposed, for example, as described in international patent application WO 2016/067192 A1 in the name of the same Applicant, wherein the noise reducing elements are initially positioned on a first conveyor belt; the noise reducing elements are then transferred onto a second conveyor belt, whereon they are coupled to a continuous film of adhesive material; as they are transferred onto a third conveyor belt, the adhesive material is cut to size, so that the noise reducing elements on the third conveyor belt are separated from one another, each one coupled to the respective portion of adhesive material.

The first conveyor 10 and the second conveyor 20 preferably correspond to said third conveyor belt.

In other words, it is envisaged that a group of conveyor belts (e.g. first, second and third conveyor belts as described in WO 2016/067192 Al) feed the noise reducing elements of the first set SI, and another group of conveyor belts (e.g. other first, second and third conveyor belts) feed the noise reducing elements of the second set S2. The first conveyor 10 may correspond, for example, to the third conveyor belt of the first group, while the second conveyor 20 may correspond, for example, to the third conveyor of the second group.

Preferably, the first conveyor 10 and the second conveyor 20 are made of non-stick material, e.g. rendered anti-adhesive by means of a surface treatment with silicones, so as to not hinder the picking up of the noise reducing elements by the robotized arm 50.

The noise reducing elements of the first set SI are arranged in order on the first conveyor 10 starting from a first initial noise reducing element El. The latter is the noise reducing element that precedes, in the advancing direction of the first conveyor 10, all the other noise reducing elements of the first set SI.

The noise reducing elements of the second set S2 are arranged in order on the second conveyor 20 starting from a second initial noise reducing element E2. The latter is the noise reducing element that precedes, in the advancing direction of the second conveyor 20, all the other noise reducing elements of the second set S2.

Preferably, the noise reducing elements of the first set SI are fed to the working station 1 in alternation to the noise reducing elements of the second set S2.

In general, the noise reducing elements of the first set SI and of the second set S2 are fed to the working station 1 in accordance with a work program that must be executed by the robotized arm 50 in order to apply the noise reducing elements to the radially inner surface 3 of the tyre 100.

The sequence of tyres supplied to the working station 1 may comprise either substantially equal tyres, in which case the noise reducing elements are applied according to the same pattern, or different tyres, in which case the noise reducing elements are applied according to different patterns. The robotized arm 50 is appropriately controlled to apply to each tyre the specific pattern associated therewith.

The robotized arm 50 picks up one noise reducing element at a time (from the first set SI or from the second set S2, in accordance with said work program) and applies it to the tyre 100.

In the example of Figure 2, the robotized arm 50 is working on the first initial noise reducing element El in a first terminal zone Z1 of the first conveyor 10. The second initial noise reducing element E2 is drawn with dashed lines, because it preferably reaches a second terminal zone Z2 of the second conveyor 20 at a later time.

When the application of noise reducing elements to the tyre 100 is complete, the working station 1 starts working on the next tyres, according to the order defined by said sequence of tyres.

It should be noted that, in the present description, reference is specifically made to the first set SI of noise reducing elements and to the second set S2 of noise reducing elements, fed by the first conveyor 10 and by the second conveyor 20, respectively. The invention may however also be implemented with a greater number of sets of noise reducing elements and respective conveyors. The working station 1 comprises a detection system 30 (Fig. 3).

The detection system 30 is configured for detecting one or more first images A, representative of at least one noise reducing element of the first set SI .

In particular, the detection system 30 may be equipped with a first detection device 31, e.g. implemented as a video camera sensitive to infrared radiations, for detecting the first images A.

In order to detect the first images A, the detection system 30, and in particular the first detection device 31, operates in the first terminal zone Z1 of the first conveyor 10. In practice, the first terminal zone Z1 of the first conveyor 10 is framed, and the first images A are taken when a noise reducing element of the first set SI is in said first terminal zone Zl .

The first images A are representative of the first initial noise reducing element El, when the latter is in the first terminal zone Zl .

As will become more apparent below, the first initial noise reducing element El may be either applied to the tyre or discarded. In any case, it will then be replaced by another noise reducing element of the first set SI arriving at the first terminal zone Zl, which will thus become the new first initial noise reducing element.

Therefore, the first images A are preferably representative of all the noise reducing elements of the first set SI, each first image A (or each group of first images A) being representative of a single noise reducing element of the first set SI when it is in the first terminal zone Zl of the first conveyor 10.

The detection system 30 is configured for detecting one or more second images B representative of at least one noise reducing element of the second set S2.

In particular, the detection system 30 may be equipped with a second detection device 32, e.g. implemented as a video camera sensitive to infrared radiations, for detecting the second images B. In order to detect the second images B, the detection system 30, and in particular the second detection device 32, operates in the second terminal zone Z2 of the second conveyor 20. In practice, the second terminal zone Z2 of the second conveyor 20 is framed, and the second images B are taken when a noise reducing element of the second set S2 is in said second terminal zone Z2.

The second images B are representative of the second initial noise reducing element E2, when the latter is in the second terminal zone Z2.

The second conveyor 20 operates in much the same way as the first conveyor 10.

Therefore, the second images B are preferably representative of all the noise reducing elements of the second set S2, each second image B (or each group of second images B) being representative of a single noise reducing element of the second set S2.

Preferably, the working station 1 comprises a contrast wall 60.

The contrast wall 60 is positioned at the first terminal zone Z1 and at the second terminal zone Z2.

In particular, the contrast wall 60 is mounted lower than the first conveyor 10 and the second conveyor 20, so that the first terminal zone Z1 and the second terminal zone Z2 are interposed between the detection system 30 and the contrast wall 60 (as schematically shown in Figure 3).

The contrast wall 60 is preferably light in colour, so as to facilitate the detection by the detection system 30. It is envisaged, in fact, that the noise reducing elements are dark in colour.

Advantageously, the contrast wall 60 can be switched between an operating position and a discarding position.

In the operating position, the contrast wall 60 is at the first and second terminal zones Zl, Z2 and, as aforesaid, facilitates the detection by the detection system 30.

In the discarding position, the contrast wall 60 is moved away from the first and/or second terminal zones Zl, Z2, thus letting the noise reducing element coming from the first conveyor 10 and/or from the second conveyor 20 fall down when it has to be discarded.

For the purpose of moving the contrast wall 60 from the operating position to the discarding position, an actuator 61 is advantageously employed, which may be a pneumatic one, for example.

The contrast wall 60 is normally in the operating position. When it has to be moved into the discarding position, the actuator 61 is activated, which will then cause the necessary movement (translation and/or rotation) of the contrast wall 60.

When the discarding operation is complete, the contrast wall 60 will be brought back into the operating position.

It should be noted that the contrast wall 60 has been described above as a single element associated with both the first terminal zone Zl and the second terminal zone Z2. However, within the scope of the present invention it is envisaged that two distinct walls may be used, one dedicated to the first terminal zone Zl and the other one dedicated to the second terminal zone Z2. Such two distinct contrast walls may be controlled by the same actuator or may be each associated with a dedicated actuator.

The working station 1 comprises a processor 40.

The processor 40 may be implemented, for example, as a conventional computer or be a part of a PLC supervising the entire operation of the working station 1. In general terms, the processor 40 may be integrated into any computer capable of interfacing with the robotized arm 50.

The processor 40 receives the first images A.

Based on the first images A, the processor 40 determines first parameters PI, associated with the noise reducing element represented in such first images A. The first parameters PI are indicative of coordinates, in a first plane parallel to the first conveyor 10, of a point representative of the at least one noise reducing element of the first set SI .

For example, the first parameters PI comprise an abscissa and an ordinate, referred to a bidimensional reference system defined on said first plane, of a geometric centre of the represented noise reducing element.

The Applicant observes that, given the substantially homogeneous structure of the noise reducing elements, their geometric centre can represent the centre of gravity with sufficient precision.

The first parameters PI are also indicative of an angle of orientation of the at least one noise reducing element of the first set SI relative to a direction determined on the first plane.

Said determined direction may be, for example, the advancing direction of the first conveyor 10.

In practical terms, the first parameters PI are indicative of where the geometric centre of the noise reducing element is located (in a plan view), and how the same noise reducing element is oriented relative to the advancing direction of the first conveyor 10.

Figure 4 schematically shows the first conveyor 10 and the first initial noise reducing element El of the first set SI positioned thereon x and y indicate the coordinates of the geometric centre of the noise reducing element, while b is the angle of orientation relative to the advancing direction D of the first conveyor 10, the axis of abscissas x being preferably parallel to said advancing direction D.

Preferably, the processor 40 determines at least one first length XI of the initial noise reducing element El of the first set SI represented in the first images A. In particular, the processor 40 can determine both the length and the width of the represented noise reducing element.

A first comparison is then made between the dimensions thus acquired and first reference values REF1.

The first reference values REF1 are representative of correct dimensions of the noise reducing element.

If the acquired dimensions are excessively different from the first reference values REF1, i.e. the acquired dimensions do not match the first reference values REF1, then the processor 40 will prevent the initial noise reducing element El from being applied to the tyre 100.

For example, if the first length XI does not match the first dimension LI, the processor 40 will not send the movement commands to the robotized arm 50 for picking up the initial noise reducing element El and will let the first conveyor 10 move on and cause the initial noise reducing element El to fall down past the first terminal zone Zl.

Conversely, if the acquired dimensions do match the first reference values REF1, then the processor 40 will generate a first movement command MCI intended for the robotized arm 50.

Preferably, the first movement command MCI is generated on the basis of the first parameters PI.

In particular, the first movement command MCI takes into account the position (abscissa x, ordinate y, orientation b) of the initial noise reducing element El, and guides the robotized arm 50 into a corresponding configuration, so that it will be able to pick up the initial noise reducing element El correctly.

In this regard, the Applicant observes that the first initial noise reducing element El may have been arranged on the first conveyor 10 in a non-ideal manner, i.e. it may not be centred (in the transverse direction) on the first conveyor 10 and/or may not be oriented parallel to the advancing direction D of the first conveyor.

Based on the first parameters PI, the processor 40 preferably determines to what extent the position and orientation of the first initial noise reducing element El differ from the ideal ones - i.e. those which the robotized arm 50, in the absence of further information, would use as a reference in order to position and orient the terminal tool 51 for picking up the first initial noise reducing element El.

The first parameters PI are thus used for correctly positioning and orienting the terminal tool 51, so as to precisely couple it to the first initial noise reducing element El. In particular, the engagement surface 52 comes to substantially match a top surface of the first initial noise reducing element El.

The first movement command MCI also causes a further movement of the robotized arm 50 in order to apply the initial noise reducing element El to the radially inner surface of the tyre 100.

In any case, due to the motion of the first conveyor 10, a next noise reducing element of the first set SI will take the position of the first initial noise reducing element El just picked up or discarded.

The processor 40 also receives the second images B and operates in the same way, thus determining second parameters P2 associated with the noise reducing elements of the second set S2 represented in said second images B (i.e. the second initial noise reducing element E2).

Such second parameters P2 are indicative of the position and orientation of the second initial noise reducing element E2.

The schematic representation of Figure 4, concerning the first conveyor 10 and the first initial noise reducing element El, also applies to the second conveyor 20 and the second initial noise reducing element E2. The second parameters P2 are preferably indicative of an abscissa, an ordinate and an orientation of the second initial noise reducing element E2.

Based on the second images B, the processor 40 determines at least one second length X2 of the second initial noise reducing element E2 of the second set S2. In particular, the processor 40 is configured for determining both the length and the width of the second initial noise reducing element E2 of the second set S2.

The second length X2, and preferably all measurements taken, are compared with second reference values REF2.

If the values match, a second movement command MC2 will be generated for the robotized arm 50 to pick up the noise reducing element and apply it to the tyre 50; as previously described with reference to the first initial noise reducing element El, the terminal tool 51 of the robotized arm 50 will be positioned and oriented according to the second parameters P2, so as to couple said terminal tool 51 to the second initial noise reducing element E2.

Conversely, if there is no matching between the second length X2 and the second reference values REF2, then the second initial noise reducing element E2 will not be applied to the tyre 100. For example, if the second length X2 does not match the second dimension L2, the second conveyor 20 will be moved on, without the second initial noise reducing element E2 being picked up, until the second initial noise reducing element E2 goes past the second terminal zone Z2.

In any case, due to the motion of the second conveyor 20, a next noise reducing element of the second set S2 will take the position of the second initial noise reducing element E2 just picked up or discarded.

When a noise reducing element has to be discarded, i.e. when there is no matching between the at least one first length XI and the first reference values REF1 and/or between the at least one second length X2 and the second reference values REF2, the processor 40 will preferably generate a discard signal DS.

The discard signal DS will be sent to said actuator 61 and cause a displacement of the contrast wall 60. In this way, the contrast wall 60 will not support or hold the discarded noise reducing element, which in the meantime will have arrived at the end of the respective conveyor 10, 20 and fallen down in front of it. The noise reducing element can then be collected in a suitable container positioned underneath the contrast wall 60 at the first and second terminal zones Zl, Z2, so that it can be further machined and given more precise dimensions, or else definitively discarded.