US-20260124816-A1 - METHOD FOR CHECKING A PROCESS FOR BUILDING A TYRE AND SYSTEM FOR CHECK THEREOF

US20260124816A1US 20260124816 A1US20260124816 A1US 20260124816A1US-20260124816-A1

Abstract

A method and system for checking a process for building a tyre including sequential deposition of an ordered plurality of N semi-finished elements on a drum. The method includes: establishing an ordered plurality of N classes of drum states, wherein a first class corresponds to a bare drum state and an i-th class corresponds to a drum state including the i-1th semi-finished element deposited in radially outermost position; before the deposition of the i-th semi-finished element: processing an acquired image of a drum state to associate to the current drum state a current class among the ordered plurality of N classes of drum states; authorising the deposition of the i-th semi-finished element based on a comparison between the current class and the expected class.

Inventors

Fabio REGOLI
Daniele PECORARO
STEFANO MARTINA

Assignees

PIRELLI TYRE S.P.A.

Dates

Publication Date: 20260507
Application Date: 20231212
Priority Date: 20221219

Claims (18)

1 .- 17 . (canceled)
18 . A method for checking a process for building a tyre, the process for building comprising the sequential deposition of an ordered plurality of N semi-finished elements on a drum, the method comprising: establishing an ordered plurality of N classes of drum states, wherein a first class corresponds to a bare drum state and an i-th class, with i ranging from 2 to N, corresponds to a drum state including an i-1th semi-finished element deposited in radially outermost position; wherein the method comprises, before deposition of the i-th semi-finished element: acquiring at least one image of a current drum state; processing said at least one image to associate to said current drum state a current class among said ordered plurality of N classes of drum states; authorising the deposition of said i-th semi-finished element on the basis of a comparison between said current class and an expected class, said expected class being the i-th class in said ordered plurality of classes.
19 . The method according to claim 18 , wherein said acquiring, processing and authorising are performed before the deposition of each i-th element of said ordered plurality of N elements.
20 . The method according to claim 19 , wherein said acquiring, processing and authorising are performed on condition of a restart from a downtime of machine.
21 . The method according to claim 20 , wherein, provided that said current class is equal to said expected class, the method further comprises authorising said deposition of said i-th semi-finished element.
22 . The method according to claim 20 , wherein, provided that said current class is different from said expected class, the method further comprises not authorising said deposition of said i-th semi-finished element.
23 . The method according to claim 20 , wherein said predetermining includes, for each class, acquiring a respective set of images of drum states belonging to said class, and associating said respective set with said class.
24 . The method according to claim 23 , where said processing comprises processing a visual appearance of a radially external surface of the current drum state.
25 . The method according to claim 23 , including comparing said at least one image with each set of images, said current class being associated as a function of a comparison between a visual appearance of a radially external surface of the current drum state in said at least one image and a respective visual appearance of a radially external surface of the drum state in each set of images.
26 . The method according to claim 25 , where said current class is the class corresponding to the set of images having overall the visual appearance of the respective surface structure most similar to the visual appearance of the surface structure of the radially external surface of the current drum state in said at least one image.
27 . The method according to claim 26 , wherein said at least one image is a two-dimensional and matrix image and said at least one image is acquired at least in a visible spectrum.
28 . The method according to claim 27 , wherein each semi-finished element is a strip of material having a length equal to or slightly greater than a circumferential development of the drum state prior to a deposition of said semi-finished element, or it is obtained by spiral winding of a continuous elongated element on the drum state.
29 . The method according to claim 28 , where semi-finished elements are selected from the group consisting of: underbelt inserts, first belt layer, second belt layer, zero-degree belt layer, tread band underlayer, tread band, sidewalls or a portion thereof.
30 . The method according to claim 28 , where semi-finished elements are selected from the group consisting of: liner, underliner, complex, first carcass ply, second carcass ply, sidewall inserts, sidewalls, underbelt inserts, anti-abrasive inserts, circumferential reinforcing elements.
31 . A process for building a tyre, the process comprising: depositing in sequence an ordered plurality of N semi-finished elements on a drum, wherein said process comprises a checking method according to claim 28 .
32 . A system for checking a machine for building a tyre, the machine being structured to deposit in sequence an ordered plurality of N semi-finished elements on a drum, the system comprising: an image acquisition device, and a command and control unit programmed and configured for, before deposition of an i-th semi-finished element: acquiring from said image acquisition device at least one image of a current drum state, processing said at least one image to associate to said current drum state a current class among an ordered plurality of N classes of drum states, wherein a first class corresponds to a bare drum state and an i-th class, with i ranging from 2 to N, corresponds to a drum state including the i-1th semi-finished element deposited in radially outermost position, and authorising the deposition of said i-th semi-finished element on the basis of a comparison between said current class and an expected class, said expected class being the i-th class in said ordered plurality of classes.
33 . The system for checking according to claim 32 , comprising a lighting system structured to illuminate at least partly said drum state.
34 . A plant for building a tyre, the plant comprising: a machine for building a tyre structured to deposit in sequence an ordered plurality of N semi-finished elements on a drum and the system for checking according to claim 32 .

Description

TECHNICAL FIELD OF THE INVENTION The present invention concerns a method for checking a process for building a tyre, a relative system for checking and a relative process and plant for building a tyre. PRIOR ART In the context of the industrial production of tyres, processes for building green (i.e. unvulcanised) tyres are known in which an ordered plurality of semi-finished elements is deposited in sequence on a building drum, rotatable around an axis. Typically, these depositions are carried out automatically by a machine. WO2012001562A1 describes a method for checking the deposition of semi-finished elements for the production of tyres. DE 102019211023A1 describes a method for measuring a junction that is open or overlapping of a layer of material during the production of green tyres. DEFINITIONS The terms “radial” and “axial” and the expressions “radially internal/external” and “axially internal/external” are used with reference to the radial direction and to the axial direction of the tyre that is being processed/green/moulded and vulcanised or of the building drum, hereinafter more simply “drum”, i.e. to a direction perpendicular to the axis of rotation of the aforementioned tyre/drum and to a direction parallel to the axis of rotation thereof, respectively. The terms “circumferential” and “circumferentially” are instead used with reference to the annular development of the tyre or said drum. By “drum state”, or similar expressions, it is intended to mean the assembly comprising the drum as such and all the elements possibly deposited on the drum. “Bare drum state” means a drum state consisting of the drum alone as such, without any element deposited on the drum. “Class of drum states” means the set of all possible drum states homogeneous with each other in relation to the presence of semi-finished elements. “Semi-finished element” means any element that is incorporated into the green tyre during the building step on the drum and that acts as a precursor of all or part of a component of the finished tyre. One or more of (in one embodiment all) such semi-finished elements may wrap around the entire circumferential development of the drum. One or more of the (in one embodiment all) semi-finished elements may be radially superimposed on each other, for example each element is deposited on top of the previously deposited element. One or more of the semi-finished elements may comprise, or consist entirely of, elastomeric compound, typically unvulcanised. “Component of the tyre” means any component, or a portion thereof, adapted to perform a function in the tyre, for example, components such as the liner, the underliner, the complex, the carcass ply(s), the underbelt inserts, the belt layers both crossed one another and at zero degrees, the tread band underlayer, the tread band, the bead core, the bead fillers, the textile reinforcement inserts, either metallic or elastomeric material only, the anti-abrasive inserts, the sidewall inserts. “Two-dimensional image”, or “2D image”, of a surface means a digital image to each pixel of which there is associated a piece of information representative of the reflectivity/diffusivity and/or colour of the surface, such as the images detected by the common digital cameras (e.g. CCD). In other words, the 2D image represents the visual appearance of the surface. “Matrix image” means a digital image whose pixels form a rectangular matrix having the two dimensions of comparable length (for example, the two dimensions differ by less than an order of magnitude, as in 4×3 or 3×2 formats). SUMMARY OF THE INVENTION As part of the process for building a tyre, the Applicant has observed that it is necessary for the semi-finished elements to be deposited correctly and/or in the correct sequence. According to the Applicant, the method for checking the deposition of semi-finished products based on the detection, directly or indirectly, of the thickness and/or of height profile of the radially external layer of the drum state, as for example described in WO2012001562A1 and DE102019211023A1, may in certain circumstances be unreliable (for example in the case of semi-finished elements that are very thin and/or with complex patterns, as in the case of bicycle tyres), and/or entail high costs for example due to the protection systems necessary for the personnel involved due to the use of laser radiations, and/or execution times not compatible with current industrial needs. The Applicant therefore dealt with the problem of checking the correct deposition of semi-finished elements in an automatic, reliable, fast manner, and/or at low cost. The Applicant has found that the use of predetermined classes of the drum state, where the current drum state is classified into one of these classes by processing an image acquired before the deposition of a semi-finished element, and where said current class is compared with the class previous to the one corresponding to the deposition of said semi-fini