Method, process and apparatus for manufacturing tyres for vehicle wheels

Abstract

In an apparatus for building tires for vehicle wheels, a forming drum is loaded on a shuttle movable on a guide along a deposition line. The shuttle is moved on the guide in the two running directions to bring it to dispensing stations of semifinished products disposed in at least some deposition locations positioned in space succession along the deposition line. At each of the dispensing stations, at least one semifinished product is laid on a radially external surface to the forming drum carried by the shuttle for forming at least one component of a tire. The shuttle is moved on the guide in a different sequence from the space succession of the deposition locations along the deposition line.

Claims

1. A process for building tyres for vehicle wheels, the process comprising: forming all components belonging to a carcass sleeve of a first tyre on a first forming drum and all components belonging to a carcass sleeve of a second tyre on a subsequent second forming drum, wherein said tyre components belonging to a carcass sleeve of said first and second tyres are formed by: loading the first forming drum at a loading and unloading location of a carcass-building line, on a single shuttle movable along a straight guide; moving the shuttle on the straight guide to bring said shuttle to a plurality of dispensing stations of semifinished products, wherein each dispensing station is disposed in a respective deposition location, and each respective deposition location is included in a plurality of deposition locations positioned in a space succession along the straight guide, wherein at each of said dispensing stations of semifinished products, a semifinished product is laid on a radially external surface of the first forming drum carried by the shuttle for forming one of the components belonging to the carcass sleeve of the first tyre; and bringing the first forming drum provided with the components formed by the dispensing stations back to said loading and unloading location and unloading said first forming drum from said shuttle before loading the subsequent second forming drum, shifting the unloaded first forming drum provided with the components formed by the dispensing stations to an apparatus at which annular anchoring structures of the first tyre are placed and turned up portions of the carcass sleeve of the first tyre are formed, then carrying the first forming drum to an apparatus at which the turned-up portions are rolled, and then to an assembling station at which an outer sleeve is coupled to the carcass sleeve of the first tyre wherein the first forming drum is moved in a first sequence among a first set selected from the plurality of deposition locations, the first sequence being different from the space succession of said deposition locations along the straight guide and wherein the first forming drum is brought at least two times to one and the same deposition location of the first set; wherein the subsequent second forming drum is moved in a second sequence among a second set selected from the plurality of deposition locations and wherein the subsequent second forming drum is brought at least two times to one and the same deposition location of the second set, the number of deposition locations of the first set being different than the number of deposition locations of the second set, wherein the space succession of the plurality of deposition locations remains unchanged, wherein only a single forming drum is located on and moved along the straight guide at a time between the times of loading and unloading that single forming drum on and from said shuttle, and the shuttle holds the single forming drum during the laying of the semifinished products; and wherein a running direction of said shuttle is reversed at least twice after the loading of the single forming drum onto said shuttle and before said shuttle is further reversed to return to the loading and unloading location during movement of said shuttle along the straight guide while forming components of each carcass sleeve of the first and second tyres.

2. The process as claimed in claim 1, wherein the loading and unloading location is disposed at an end of the straight guide.

3. The process as claimed in claim 1, wherein deposition of the semifinished product on the radially external surface of the first forming drum at each of said dispensing stations comprises: moving the first forming drum close to a conveying surface of the respective dispensing station, the respective conveying surface being movable along a feeding direction; feeding the respective semifinished product onto said respective conveying surface; and setting the first forming drum in rotation for receiving the respective semifinished product on the radially external surface.

4. The process as claimed in claim 3, wherein during the deposition onto the first forming drum at each of said dispensing stations the first forming drum is moved from an upper position to a lower position, wherein, at the lower position, the first forming drum is close to a final end of the respective conveying surface.

5. The process as claimed in claim 3, wherein during the deposition onto the first forming drum at each of said dispensing stations the first forming drum is moved from a lower position to an upper position, wherein, at the upper position, the first forming drum is close to a final end of the respective conveying surface.

6. The process as claimed in claim 1, wherein, before forming the components on the first forming drum, a dispensing station of semifinished products not used with the first forming drum is removed from one of the deposition locations and replaced with one of the dispensing stations that is used on the first forming drum.

7. The process as claimed in claim 1, wherein, before forming the components on the first forming drum, one of the dispensing stations of semifinished products is removed from one of the deposition locations and added in a different deposition location of the plurality of deposition locations.

8. The process as claimed in claim 1, wherein, before forming the components on the first forming drum, a dispensing station of semifinished products not used with the first forming drum is removed from one of the deposition locations.

9. The process as claimed in claim 1, wherein, as the first forming drum is moved to each of the dispensing stations disposed in the first set of deposition locations, the first forming drum is disposed above an end of a conveying surface of the respective dispensing stations.

10. The process as claimed in claim 1, wherein, in the first set of deposition locations, the first forming drum is lowered until the first forming drum bears against the semifinished product dispensed from the respective dispensing stations.

11. The process as claimed in claim 1, wherein, in each of said deposition locations in the first set, the semifinished product is dispensed from a removable carriage that is housed in a frame that is locked in and removable from the respective deposition location.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Further features and advantages will become more apparent from the detailed description of a preferred but not exclusive embodiment of a method, a process and an apparatus for building tyres for vehicle wheels, in accordance with the present invention.

(2) This description will be set out hereinafter with reference to the accompanying drawings, given by way of non-limiting examples, in which:

(3) FIG. 1 diagrammatically shows a plan view of an apparatus for manufacturing tyres for vehicle wheels according to the present invention;

(4) FIG. 2 is a view of a portion of the apparatus seen in FIG. 1 according to an alternative embodiment;

(5) FIG. 3a is an elevation side view of an element of the apparatus in FIG. 2;

(6) FIG. 3b shows a variant of the element seen in FIG. 3a;

(7) FIG. 3c shows a portion of a further variant of the element in FIG. 3a;

(8) FIG. 4 is a radial half-section of a tyre built using the apparatus seen in FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

(9) With reference to FIG. 1, an apparatus for building tyres for vehicle wheels in accordance with the present invention has been generally identified with reference numeral 1.

(10) A tyre 2, manufactured in said apparatus and using the method and the process according to the present invention, is shown in FIG. 4 and it essentially comprises a carcass structure 3 having two carcass plies 4a, 4b. A layer of airtight elastomeric material or so-called liner 5 is internally applied to the carcass ply/plies 4a, 4b. Two annular anchoring structures 6, each comprising a so-called bead core 6a carrying an elastomeric filler 6b at a radially external position, are in engagement with respective end flaps of the carcass ply/plies 4a, 4b. The annular anchoring structures 6 are integrated in the vicinity of regions usually referred to as beads 7, at which usually engagement of the tyre 2 with a respective mounting rim occurs. A belt structure 8 comprising several belt layers 8a, 8b is circumferentially applied around the carcass plies 4a, 4b and a tread band 9 circumferentially overlaps the belt structure 8.

(11) So-called under-belt inserts 10 can be associated with the belt structure 8 and each of them is placed between the carcass plies 4a, 4b and one of the axially opposite end edges of the belt structure 8. Two sidewalls 11, extending each from the corresponding bead 7 to a corresponding side edge of the tread band 9, are applied at laterally opposite positions to the carcass plies 4a, 4b.

(12) Said components of tyre 2 are manufactured on one or more drums shifting said drums between different dispensing stations of semifinished products at each of which suitable devices apply the aforesaid semifinished products onto the forming drum or drums.

(13) The apparatus 1 shown in the accompanying figures comprises a carcass-building line 12, at which forming drums 13 are moved between different dispensing stations of semifinished products provided to form, on each forming drum 13, a carcass sleeve comprising the carcass plies 4a, 4b, liner 5, annular anchoring structures 6 and possibly at least part of the sidewalls 11.

(14) Simultaneously, in an outer-sleeve building line 14, one or all auxiliary drums are sequentially moved between different work stations designed to form an outer sleeve on each auxiliary drum, which outer sleeve comprises at least the belt structure 8, tread band 9 and possibly at least part of the sidewalk 11.

(15) The apparatus further comprises an assembling station 15 at which the outer sleeve is coupled to the carcass sleeve.

(16) The built tyres 2 are finally transferred to at least one vulcanisation and moulding unit, not shown.

(17) The carcass-building line 12 comprises a guide 16 preferably extending straight along a deposition line L. Mounted on guide 16 is a shuttle 17 capable of moving, driven by a suitable motor not shown, along guide 16 and in both the running directions S1, S2. Shuttle 17 is able to support a forming drum 13 at a time, and rotate it around a rotation axis X-X coincident with the longitudinal symmetry axis of the drum 13 itself and with the rotation axis of tyre 2 under production. In the embodiment shown, the drum 13 is carried in overhanging by shuttle 17, which comprises a grip element adapted to retain or release a final end of a central shaft of the forming drum 13.

(18) Alongside guide 16 and preferably, as shown, on a side alone of the latter, deposition locations 18i, 18ii, 18iii, 18iv, 18v, 18vi are present (six in number in the example in FIGS. 1 and 2) which are disposed consecutively after each other. More generally, in other variants of the apparatus, not shown, the n number of the deposition locations can be preferably included between four and ten.

(19) At least some of said deposition locations 18i, 18ii, 18iii, 18iv, 18v, 18vi house each a respective dispensing station of a semifinished product. More generally, preferably, the m number of deposition locations 18i, 18ii, 18iii, 18iv, 18v, 18vi occupied by a dispensing station is preferably included between three and ten.

(20) As shown in the accompanying FIG. 1, a first deposition location 18i houses a dispensing station 19 for supplying liner 5, a second deposition location 18ii and a third deposition location 18iii are empty, a fourth deposition location 18iv houses a dispensing station 20 for supplying the first carcass ply 4a, a fifth deposition location 18v is empty and a sixth deposition location 18vi houses a dispensing station 21 for supplying the second carcass ply 4b. The apparatus shown in FIG. 1 is therefore provided for building tyre 2 shown in FIG. 4.

(21) According to an alternative embodiment shown in the accompanying FIG. 2, the first deposition location 18i houses a dispensing station 22 for feeding the complex-liner 22a (intended as single semifinished product comprising liner, under-liner and abrasion-proof elongated elements), the second deposition location 18ii houses a dispensing station 23 for feeding sidewall inserts 23a, the third deposition location 18iii is empty, the fourth deposition location 18iv houses a dispensing station 24 for feeding a first carcass ply 24a, the fifth deposition location 18v houses a dispensing station 25 for feeding edges 25a and the sixth deposition location 18vi houses a dispensing station 26 for feeding a second carcass ply 26a. The apparatus shown in FIG. 2 is therefore intended for building the run-flat tyre, not shown.

(22) Each of the mentioned dispensing stations 19, 20, 21, 22, 23, 24, 25, 26 substantially has the same structure as diagrammatically shown in FIG. 3a with reference to the dispensing station 24 for the first carcass ply 24a of FIG. 2, so that in the following the same reference numerals of the components of the dispensing station 24 will be used for the corresponding components of the other dispensing stations of semifinished products.

(23) This dispensing station 24 comprises a frame 27 lying in the respective fourth deposition location 18iv. Frame 27 can be locked in the respective fourth location 18iv during the work steps and can be removed away from said fourth location 18iv, preferably by means of wheels not shown, secured to the frame 27 itself in a removable manner. Frame 27 internally delimits a space 28 designed to house a carriage 29 movable on wheels 30. The carriage 29 carries the semifinished product (in the concerned case the first carcass ply 24a) coupled to a service fabric 31 and wound up into a coil on a rotatable reel-holder 32 freely rotating or powered.

(24) At an upper portion of frame 27, above the space 28 for carriage 29, a first conveyor belt 33 is placed which has a horizontal upper conveying surface 34. This horizontal upper conveying surface 34 is moved forward along a feeding direction F. Downstream of the first conveyor belt 33, relative to said feeding direction F, a second conveyor belt 35 is consecutively disposed, which has an upper conveying surface 36 inclined downwards starting from the first conveyor belt 33. This inclined upper conveying surface 36 is moved forward along the feeding direction F. The two upper conveying surfaces 34, 36 define an overall conveying surface for the semifinished product wound into a coil in carriage 29, which extends starting from a rear portion of the dispensing station 24 and ends at the guide 16, when the dispensing station 24 is installed in the respective deposition location 18iv. In a plan view (FIGS. 1 and 2), the feeding direction F is perpendicular to said guide 16.

(25) The semifinished product 24a is unwound from the reel and separated from the service fabric 31. The service fabric 31 is wound up on a respective collecting reel 37. The semifinished product 24a forms a festoon and is then guided and directed, from bottom to top, to the horizontal upper conveying surface 34, at the rear portion of the dispensing station 24, by means of guide elements 38 (rollers for example) carried by the carriage and/or installed on frame 27.

(26) In a variant, shown in FIG. 3b, a semifinished product of a type different from the carcass ply 24a, is directly delivered onto the conveying surfaces 34, 36 by an extruder E.

(27) Positioned on top of the conveyor belts 33, 35 is a cutting device 39 for cutting to size the semifinished product 24a fed onto the conveying surface. The cutting device 39 diagrammatically shown in FIG. 3a is placed between the first and second conveyor belts 33, 35.

(28) A final end 40 of the second conveyor belt 35 is positioned close to guide 16 so that the shuttle 17 and drum 13 carried thereby can be disposed above a final end of the overall conveying surface 34, 36. As the shuttle 17 moves along guide 16, it is able to bring the drum 13 above each of the overall conveying surfaces 34, 36 of each dispensing station 19, 20, 21, 22, 23, 24, 25, 26 and stop it at this position.

(29) In an alternative embodiment shown in FIG. 3c, the final end 40 of the conveying surface 34, 36 is disposed on top of the forming drum 13, for deposition of a strip of self-sealing material for tyres, for example.

(30) In a further preferred embodiment (not shown) the final end 40 of the conveying surface 34, 36 is substantially disposed at the height of the rotation axis X-X of the forming drum 13, should it be necessary to spiral a semifinished product having nylon cords, for example.

(31) The shuttle 17 further comprises actuating devices, not shown, adapted to vertically move the grip element and drum 13 secured thereto in the two ways V1, V2, along a direction orthogonal to the longitudinal extension of guide 16. The drum 13 is therefore movable between a first position at which a radially external surface thereof 13a approaches the upper conveying surface 34, 36, and a second position at which said radially external surface is moved away from said overall conveying surface 34, 36.

(32) The feeding direction F of the semifinished product is perpendicular to a plane containing the rotation axis X-X at the winding-up point on the drum 13.

(33) At one of the final ends of guide 16 a loading and unloading location 41 is placed where, by suitable devices not shown, each forming drum 13 can be loaded on the shuttle 17 or unloaded therefrom.

(34) Also positioned at the loading and unloading location is an apparatus 42 for placement of the annular anchoring structures 6 and turning up of the end flaps of the carcass plies 4a, 4b and an apparatus 43 for rolling the turned-up portions, known by themselves and therefore not further described or illustrated.

(35) In use, in accordance with the method and process of the invention, based on the recipe of the tyre to be built, installed in some or all of the n deposition locations (six in number in the examples shown) are m dispensing stations (m corresponding to three in FIG. 1, m corresponding to five in FIG. 2).

(36) A control unit U, only shown in FIG. 2, operatively connected to sensors and motors of apparatus 1, is programmed in such a manner that the dispensing stations lay down the respective semifinished products in a predetermined sequence on each forming drum 13.

(37) With reference to the embodiment in FIG. 1, the shuttle 17 carries the empty forming drum 13 close to the first deposition location 18i. In this location, the dispensing station 19 feeding liner 5 has already carried out the cut to size of a strip of liner 5 lying immobile on the conveying surface 36 of the second conveyor belt 35. The forming drum 13 is lowered until it bears against the strip of liner 5 and set in rotation until it fully winds said strip of liner 5 on its radially external surface 13a while the conveying surface 36 is moving forward along the feeding direction F so as to help this winding operation. When winding has been completed, the shuttle 17 raises the forming drum 13 and moves it to the fourth deposition location 18iv, skipping the second 18ii and third 18iii deposition locations, for receiving the first carcass ply 4a, and then to the fifth deposition location 18v for receiving the second carcass ply 4b, in the same manner as done for liner 5, and forming a carcass sleeve.

(38) With reference to the embodiment in FIG. 2, the shuttle 17 is moved to and stopped at the first 18i and second 18ii deposition locations, the third deposition location 18iii being skipped, and then moved to and stopped at the fourth 18iv, fifth 18v and sixth 18vi deposition locations.

(39) With reference to both the embodiments shown (FIGS. 1 and 2), the shuttle 17 then changes its running direction and is brought back to the loading and unloading location 41 where the mentioned suitable devices pick up the forming drum 13 provided with the just formed carcass sleeve and shift it into apparatus 42 for placement of the annular anchoring structures 6 and carrying out turning up of the end flaps of the carcass plies 4a, 4b.

(40) The forming drum 13 is then carried to apparatus 43 for rolling the turned-up portions and then to the assembling station 15.

(41) To change the type or design of tyre being built, in the carcass building line 12 it is possible: to remove and/or add and/or replace one or more dispensing stations of semifinished products and/or change the position thereof in the deposition locations, and/or to replace the carriages and/or the reels carried thereby, and/or to change the sequence according to which the shuttle 17 brings the drum 13 to said dispensing stations of semifinished products. By suitably installing the dispensing stations of semifinished products, the drum 13 can be, for example, first brought to the sixth deposition location 18vi, subsequently to the fourth 18iv, then to the first 18i and the second 18ii, then again to the sixth 18vi and finally brought back to the loading and unloading station 41.