Method for depositing a piece of band-like elastomeric element on a forming support in a process for building a tyre for vehicle wheels

Patent metadata

Field	Value
Publication number	US-11433631-B2
Application number	US-201415102764-A
Country	US
Kind code	B2
Filing date	Dec 12, 2014
Priority date	Dec 13, 2013
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

A method for depositing a piece of band-like elastomeric element on a forming support in a process for building a tyre for vehicle wheels. The method includes feeding a piece of band-like elastomeric element having a predetermined nominal length towards the forming support along a predetermined feeding direction and measuring the actual length of the piece along the feeding direction. If the actual length is lower than or equal to a circumferential length of a deposition surface defined on the forming support, the piece is deposited on the deposition surface while the forming support rotates about a rotation axis thereof. During such deposition the piece is pressed on the deposition surface with a pressing force selected as a function of the actual length.

First claim

The invention claimed is:

1. A method for depositing a piece of band-like elastomeric element on a forming support in a process for building a tyre for vehicle wheels, comprising:
providing a reference image acquired in a previous calibration process in which a template of a known length of the band-like elastomeric element was used;
feeding a piece of band-like elastomeric element having a predetermined nominal length towards said forming support along a predetermined feeding direction;
measuring an actual length of said piece of band-like elastomeric element along said feeding direction via the following steps:
a) detecting a first instant of passage of a head end of said piece of band-like elastomeric element;
b) determining a second instant of passage of a tail end of said piece of band-like elastomeric element as a function of said first instant of passage, said nominal length and a speed of movement of the band-like elastomeric element;
c) acquiring a single image of the tail end at the second instant determined in step b); and
d) calculating the actual length of said piece of band-like elastomeric element based on the detection of said first instant and second instant;

wherein calculating the actual length of said piece of band-like elastomeric element comprises:
comparing the single image with the reference image; and
determining the actual length of said piece of band-like elastomeric element based on a comparison between said single image and said reference image,
if said actual length is lower than or equal to a circumferential length of a deposition surface defined on the forming support, depositing said piece of band-like elastomeric element on said deposition surface while said forming support rotates about a rotation axis thereof;
if said actual length is lower than said circumferential length of said deposition surface, then:
i) obtaining from an adaptive correlation table a pressing force that corresponds to the actual length; and
ii) during the deposition of said piece of band-like elastomeric element on said deposition surface pressing said piece of band-like elastomeric element on said deposition surface with said pressing force, thereby stretching said piece so that, at the end of the deposition of said piece, a corrected actual length of said piece that substantially coincides with said circumferential length of said deposition surface is obtained.

2. The method according to claim 1 , wherein said piece of band-like elastomeric element is a tread band.

3. The method according to claim 1 , further comprising, updating the adaptive correlation table in real time.

4. The method according to claim 1 , wherein determining said second instant comprises:
determining, starting from said first instant, the instant at which said piece of band-like elastomeric element moved along said feeding direction by a length equal or close to said nominal length.

5. The method according to claim 1 , wherein said single image and said reference image are acquired through a telecamera.

6. The method according to claim 1 , wherein comparing said single image with the reference image comprises:
determining in said single image the position of a first theoretical line representative of said tail end.

7. The method according to claim 1 , comprising, at the end of the deposition of said piece of band-like elastomeric element on said deposition surface:
reversing at least once the direction of rotation of said forming support;
increasing said pressing force by a predetermined value.

8. The method according to claim 1 , wherein pressing said piece of band-like elastomeric element comprises pressing, instant by instant, two circumferentially adjacent portions of piece deposited on said deposition surface.

9. The method according to claim 1 , wherein said pressing force has different values along a transversal direction substantially perpendicular to said feeding direction.

10. The method according to claim 1 , wherein said piece of band-like elastomeric element is moved along said feeding direction up to said forming support with a substantially constant feeding speed.

11. The method according to claim 1 , comprising, during the deposition of said piece of band-like elastomeric element on said deposition surface, increasing the rotation speed of said forming support by a predetermined value selected as a function of said pressing force.

12. The method according to claim 1 , wherein said pressing force produces a stretching of said piece of band-like elastomeric element up to a maximum of 5% of its actual length measured along said feeding direction.

13. The method according to claim 1 , wherein if said actual length is greater than said circumferential length of said deposition surface defined on the forming support, said piece of band-like elastomeric element is discarded.

Assignees

• Pirelli

Inventors

• Pulici Lorenzo
• Paleari Stefano

Classifications

• B29D30/44 Primary

  Stretching or treating the layers before application on the drum (during application B29D30/30) · CPC title

• G01B11/043

  for measuring length · CPC title

• G01B21/042

  Calibration or calibration artifacts (G01B3/30, G01B9/02072 take precedence) · CPC title

• B29D30/30

  Applying the layers; Guiding or stretching the layers during application {(applying tread bands to carcasses B29D30/58; retreading B29D30/54)} · CPC title

• B29D30/3007

  by feeding a sheet perpendicular to the drum axis and joining the ends to form an annular element (bending sheets and joining the edges B29C53/42) · CPC title