Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2001-12-13
2004-08-31
Knable, Geoffrey L. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S130700, C156S133000, C156S396000
Reexamination Certificate
active
06783618
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing a tire for vehicle wheels, of the type comprising the steps of: forming a carcass sleeve comprising a pair of annular reinforcing structures at the beads axially spaced apart from each other and at least one carcass ply having opposite end flaps each turned up at one of said annular reinforcing structures; transferring the carcass sleeve onto a shaping drum; shaping the carcass sleeve into a toroidal configuration to apply it to a belting structure at a radially inner position thereof and to a tread band circumscribing said belting structure; applying a pair of sidewalls against side surfaces of the carcass sleeve, each of said pair of sidewalls extending radially between one of the annular reinforcing structures and a side edge of the tread band.
The invention also relates to an apparatus for manufacturing a tire for vehicle wheels comprising: a building drum to form a carcass sleeve comprising a pair of annular reinforcing structures at the beads axially spaced apart from each other, and at least one carcass ply having opposite end flaps each turned up at one of said annular reinforcing structures; a shaping drum to form a tire comprising said carcass sleeve, a belting structure paired with a radially external tread band, and a pair of sidewalls applied against respective side surfaces of the carcass sleeve, each of them extending between one of said annular reinforcing structures at the beads and a side edge of the tread band, applicator devices being associated with the shaping drum to apply each sidewall to the respective side surface of the carcass sleeve; transfer devices for moving the carcass sleeve from the building drum to the shaping drum.
2. Description of the Related Art
A tire for vehicle wheels generally comprises a carcass structure having at least one carcass ply provided with respectively opposite end flaps each turned up in the form of a loop around annular reinforcing structures, each of which is usually made up of a circumferentially inextensible annular insert to which at least one filling insert is applied at a radially outer position thereof.
Associated with the carcass structure is a belting structure comprising one or more textile belt layers disposed in radial superposed relationship with respect to each other and to the carcass ply and provided with textile or metallic reinforcing cords of a respectively crossed orientation or substantially parallel to the circumferential extension direction of the tire. Applied to the belting structure, at a radially outer position thereof, is a tread band also made of elastomer material like other semifinished constituent parts of the tire.
It is to be pointed out that, to the aims of the present invention, by the term “elastomer material” it is intended a rubber blend in its entirety, that is the assembly made up of a base polymer suitably amalgamated with reinforcing fillers and/or process additives of various types.
Also applied to the side surfaces of the carcass structure, each extending from one of the side edges of the tread band until close to the respective annular reinforcing structure at the beads, are respective sidewalls of elastomer material that, depending on the different embodiments, can have respective radially-external end edges either superposed on the side edges of the tread band to form a construction pattern of the type usually referred to as “overlying sidewalls” or interposed between the carcass structure and the side edges of the tread band, according to a construction pattern of the type referred to as “underlying sidewalls”.
In most of the known processes for tire building the carcass structure and the belting structure, together with the respective tread band, are provided to be made separately from each other at respective work stations, to be subsequently mutually assembled.
More particularly, accomplishment of the carcass structure first involves that the carcass ply or plies should be laid down on a first drum, usually identified as “building drum”, to form a cylindrical sleeve. The annular reinforcing structures at the beads are fitted or formed on the opposite end flaps of the carcass ply or plies, that are then turned up around the annular structures so as to enclose them as in a loop.
Simultaneously, on a second or auxiliary drum an outer sleeve is buildingd which is made up of the belt layers laid down in radially superposed relationship with respect to each other and to the tread band applied to the belt layers at a radially outer position. The outer sleeve is then picked up from the auxiliary drum to be transferred onto the carcass sleeve for the purpose of carrying out coupling therewith.
Assembling between the carcass sleeve and outer sleeve can be executed on the same drum used for making the carcass sleeve, in which case the concerned process is identified as “one-step manufacturing process”. Alternatively, assembling can be executed on a so-called shaping drum onto which the carcass sleeve and outer sleeve are transferred, to carry out tire building following a so-called “two-step manufacturing process”.
In the one-step process, application of the sidewalls takes place with the aid of the same building drum as used for formation of the carcass sleeve. The process varies depending on whether the sidewalls are first laid down on the drum or they are directly laid down on the carcass sleeve after the end flaps thereof have been turned up around the annular reinforcing structures. In the last mentioned case, in order to obtain a construction pattern of the “underlying sidewall” type, each sidewall is provided to be made by laying down a strip of elastomer material on the carcass sleeve disposed in a cylindrical conformation on the drum, taking good care that the axially outer edge of the elastomer material strip should be positioned in superposed relationship with the end flap of the carcass ply already turned up around the annular reinforcing structure. The width of the elastomer material strips is such selected that the outer end flaps of the sidewalls lend themselves to be covered with the side edges of the tread band when, concurrently with an axial approaching movement of the two halves forming the drum and retaining the respective annular reinforcing structures of the carcass sleeve, said carcass sleeve is shaped into a toroidal configuration for matching with the inner surface of the outer sleeve previously placed at a centred position on the drum.
On the contrary, in order to obtain a construction pattern of the “overlying sidewall” type, it is preferable for the strips of elastomer material designed to make the sidewalls to be laid down on the building drum at an axially outer position with respect to the annular reinforcing structures.
The sidewall strips can be paired with the end flaps of the carcass ply so as to be turned up together with the latter, or they may stay separated from said flaps in order to enable turning up of the end flaps around the annular reinforcing structures at the beads separately from turning-up of the sidewalls, generally before shaping the carcass sleeve into a toroidal conformation.
At all events, after the carcass structure has been shaped into a toroidal configuration and matched with the outer sleeve, appropriate expandible portions of the building drum, consisting of a system of levers or of inflatable bags for example, cause overturning of the strips of elastomer material in order to apply them against the side surfaces of the carcass structure.
Methods and apparatuses operating in accordance with the above-mentioned principles are described in documents FRA-2.093.180 and U.S. Pat. No. 3,990,931, for example.
Referring now to the two-step manufacturing processes, the construction pattern of the “underlying sidewall” type is obtained by laying down the elastomer material strips on the carcass sleeve in the same manner as above described with reference to the one-step manufacturing process.
In fact, the sidewalls are a
Bosio Gian Luigi
Lacagnina Claudio
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Knable Geoffrey L.
Pirelli Pneumatici S.p.A.
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