Abstract: A tire, intended to be inflated but capable of running in a deflated condition, the carcass (2) of which incorporates, at each of the sidewalls (5) thereof, a first and a second reinforcing insert (16, 17) having in section a substantially lenticular form tapering to the ends, interposed between a first carcass ply (10) and a second carcass ply (11) and mutually joined at the tire maximum-chord point. Also applied to each sidewall against the carcass ply (10) turned to the inner part of the tire is an elastic support insert (13) of lenticular section having a maximum thickness portion (13a) disposed at the junction point (18) between the two reinforcing insertions (16, 17). The elastic support insert (13) comprises a substantially stiff counter core (14) of lenticular section, and a cover (15) made of elastomeric material have a low modulus of elasticity, coating the counter core (14) at one side thereof turned towards the carcass plies.
Abstract: A toroidal semifinished product (5) made of raw elastomeric material is semivulcanized in a semivulcanization chamber (4) defined between two half-molds (2, 3) disposed close to each other. A pressure, preferably equal to the pressure exerted by the gases generated in the semifinished product (5), is created in the mold (1a). The half-molds (2, 3) are moved apart from each other and pressure in the mold is gradually reduced, thereby giving rise to the expansion and consequent transferring of the semifinished product (5) from the semivulcanization chamber (4) to a surrounding final vulcanization chamber (6). When the inner diameter of the semifinished product (5) is larger than the inner diameter of the final vulcanization chamber (6), said chamber is closed at its inner circumferential edge and then, after possible pressure increase in the mold, at its outer circumferential edge, in order to integrally enclose the semifinished product and enable completion of the vulcanization process.
Abstract: A tire, intended to be inflated but capable of running in a deflated condition, the carcass (2) of which incorporates, at each of the sidewalls (5) thereof, a first and a second reinforcing insert (16, 17) having in cross-section a substantially lenticular form tapering to the ends, interposed between a first carcass ply (10) and a second carcass ply (11) and mutually joined at the tire maximum-chord point. Also applied to each sidewall against the carcass ply (10) turned to the inner part of the tire is an elastic support insert (13) of lenticular cross-section having a maximum thickness portion (13a) disposed at the junction point (18) between the two reinforcing insertions (16, 17). The elastic support insert (13) comprises a substantially stiff counter core (14) of lenticular cross-section, and a cover (15) made of elastomeric material have a low modulus of elasticity, coating the counter core (14) at one side thereof turned towards the carcass plies.
Abstract: A plant for assembling elastomeric pneumatic tires having a plurality of assembling drums (2) moveable along a predetermined assembling path. Each drum encounters, according to a pre-established sequence, a number of primary work stations (10, 11, 12, 13) each intended for the application of a respective main component (4, 5, 6, 7) common to a plurality of carcass types included in a predetermined production range. Alongside the primary stations are auxiliary work stations (14, 15) intended for applying specifically provided accessory components (8, 9), each being designed for a particular carcass type. Each auxiliary station can be removed and replaced by a different station depending on the type of process to be carried out and is movable between a rest position in which it is perpendicularly moved away from the assembling path and a work position in which it is operatively disposed along the assembling path, in order to execute the application of the respective accessory component.
Abstract: The invention refers to the manufacture of a pneumatic tire having a toric profile at high transversal curvature wherein the reinforcing annular structure and the tread band are shaped together, starting from a cylindrical configuration to the final topic profile, in a single shaping step, before being assembled to the carcass, the step for vulcanizing the pneumatic tire being carried out without requiring a further shaping of the pneumatic tire.
Abstract: The dynamic setting of an apparatus (1) designed to check the behavior of tires comprises a rotating drum (9) arranged to act in thrust relation on a rotatable tire. A dynamometer cell (10) is connected to an electronic processing unit (12) for detecting the dynamic forces transmitted from the tire (5) to the drum (9). The setting is carried out by applying a predetermined static load to the drum (9) and afterwards transmitting cyclic dynamic forces having a predetermined frequency, intensity and dynamic variation to said drum. The cyclic forces are produced by an eccentric (20) transmitting a reciprocating motion to a movement block (22) connected to the dynamometer cells (10) by springs (29, 31). Signals emitted by the dynamometer cells (10) are detected and stored by the processing unit (12) in order to obtain data to be compared with signals emerging during the test of a tire (5).
Abstract: In a vulcanization press of the B.O.M. type, a vulcanization chamber has respective end edges (5a, 5b) connected to a disc (6) movable upon command of an actuator (8) and a disc (9) which is fixed relative to said actuator. The movable disc is fastened to a grasping head (17) provided with quick release pins (20), integral with the end of a drive rod (7) operable by a lower piston (11) contained in the actuator. The fixed disc is engaged by radially retractable latches (29) to a grasping ring (28) fastened to the actuator. The raising of the movable disc is stopped due to the chamber tensioning. The disc descent is stopped by two semi-cylindrical elements (12a, 12b) movable close to the drive rod, acting in abutment on an upper piston (15) contained in the actuator.
Abstract: A tire tread with good noise characteristics according to the invention includes at least one circumference in which a composed sequence of a plurality of design elements, are consecutively disposed in succession. Each design element having varying circumferential lengths, or pitches wherein the pitches are reduced in number, less than or equal to 3 and preferably 2, and are disposed in a random and disordered succession is present. Also disclosed is a design method which generates automatically, in a random or pseudo-random mode, one or more sequences in which the greatest part of the obtained sequences presents good sonorous properties and are selectable across the various characteristic values obtainable from the same sequences.
Type:
Grant
Filed:
January 15, 1991
Date of Patent:
December 6, 1994
Assignee:
Pirelli Coordinamento Pneumatici S.p.A.
Inventors:
Paolo Bandel, Roberto Bergomi, Carlo Monguzzi
Abstract: A tread pattern of a radial tire for motor-vehicles offering high performance comprises oblique longitudinal grooves, inclined to the circumferential direction of the tire by an angle included between 2.degree. and 20.degree., the opposite ends of said grooves being axially offset relative to one another: all grooves may be inclined in the same direction or may converge, preferably symmetrically, towards the mid-circumferential plane of the tire, specifically for directional patterns. The longitudinal grooves are associated with a plurality of transverse grooves having their central portion inclined in the opposite sense relative to the longitudinal grooves, according to an angle included between 30.degree. and 80.degree., with respect to the circumferential tire direction. The combination of the longitudinal and transverse grooves according to the established inclinations defines plugs on the tire contact-area.
Abstract: A method for production of tires in a curing mold make of a plurality of shaped blocks. The blocks are displaced circumferentially so as to leave a width clearance therebetween, the clearance being wide enough to permit air trapped within the mold to escape, but to prevent escape of elastomeric material and thus avoid generation of burrs on the surface of the tire.
Abstract: An elasomeric mix for pneumatic tire treads to enhance driving behavior including road holding ability on wet surfaces, abrasion resistance and low rolling resistance. The inventive elastomeric mix on E"/E' ratio dynamic moduli value equal to or greater than 0.3 at 0.degree. C. and equal to or less than 0.16 at 70.degree. C. The mix is based upon natural rubber and lampblack comprising, for 100 parts of elastomer, from 5 to 20 parts by weight of a synthetic polymer selected from the group consisting polychloroprene, chlorinated butyl rubber and brominated butyl rubber.
Abstract: At least one metal wire embedded in a vulcanized elastomeric matrix obtained from a mixture comprising at least one vulcanizable elastomer and at least one vulcanization agent such as sulfur. The metal wire is galvanized steel and the vulcanizable mixture contains at least 0.2% by weight of trimercapto triazine, with respect to the weight of said elastomer, and 0.1-0.5% by weight of cobalt, with respect to the weight of said elastomer.
Abstract: A metal wire for reinforcing articles made of elastomeric material, especially vehicle tires. The subject wire has a coating formed by two concentric layers of zinc-nickel or zinc-cobalt alloys, the radially inner layer of which has a zinc content greater than 90% while the radially outer layer has a nickel or cobalt content greater than 50%.
Type:
Grant
Filed:
September 9, 1992
Date of Patent:
August 16, 1994
Assignee:
Pirelli Coordinamento Pneumatici S.p.A.
Inventors:
Wim J. Van Ooij, Jayaramachandran Giridhar
Abstract: A tread for motor vehicle tires having circumferential grooves (3) and transverse grooves (4), a plurality of tread blocks (5, 6) circumferentially spaced apart to form two shoulder rows (5) and at least one central row (6) located between the shoulder rows. Each block (5, 6) is provided with one or more sipes or slits (11, 12) that are rectilinear and inclined with respect to the axis of rotation of the tire (2). The sipes (11, 12) of the blocks (5, 6) which constitute each of the shoulder and central rows are parallel to one another. The sipes (12) of the central rows (6) have an inclination, with respect to the axis of rotation, that is greater than the inclination of the sipes (11) of the blocks (6) which constitute the shoulder rows. This arrangement of the sipes (11, 12) substantially reduces the rolling noise of the tire.
Abstract: In the manufacture of a tire having a metal bead core, a covering structure (6) is associated with each bead core, which structure consists of a sheet (7) made of unvulcanized elastomeric material wrapped around the bead core and a strip of unvulcanized rubberized fabric (8), reinforced with heat-shrinkable material cords, wound around the elastomeric material sheet (7). The bead cores (3) are subsequently assembled with other tire components, and afterwards a tire vulcanization step is carried out. During this step the chemical bonding between the elastomeric sheet (7) and the bead core (3) is achieved, which bonding is promoted by the simultaneous shrinkage of the cords provided in the rubberized fabric strip (8).
Abstract: A pneumatic tire having a carcass 1 and at each sidewall 5 thereof are a first and a second elastomeric reinforcement inserts 13, 15 interposed between a first and a second carcass plies 10, 11. Each insert is thinner towards the respective opposite radial ends of its section. The reinforcement inserts 13, 15 are adjacent and in alignment with the maximum width of the tire 2 at a point 14. A third elastomeric insert 16 of lenticular section, internally covers the first carcass ply 10 and has an area of maximum thickness 16a in substantial alignment with the point of adjacency 14 between the reinforcement inserts 13, 15. The first and second reinforcement inserts 13, 15 behave like stiff arms, mutually hinged at their point 14 of adjacency. The movement of the arms toward each other is counteracted by a third elastomeric insert 16 acting as a spring therebetween.
Abstract: In a metallic mold, all or a part of the annular portion for molding at least the tread of the tire is formed by a plurality of small separate pieces that can be combined to form said annular portion. Between these small pieces, during the molding of the tire, clearances are maintained so as to permit the passage of air but not the passage of rubber. The above clearances are connected through vent holes to air suction means. Such vent holes are also connected with means for blowing pressure fluid through the clearances. The construction of this mold portion by means of small pieces made with cuts of the aforementioned portion in the axial and the circumferential direction permits regulation of the width of the clearances with respect to the rheometric characteristics of the elastomeric material to be molded and to adapt easily the mold to different tire sizes by increasing or decreasing the number of such pieces.
Abstract: A process for applying a belt structure during the manufacture of a large heavy duty tire such as for an earthmover machine including forming a belt band 5 obtained by adhering together two rubberized fabric strips 8, 9 so as to be laterally offset with respect to each other. Each strip has reinforcing cords 8a, 9a disposed according to symmetrically cross-biased orientations. A belt band made of at least two adhered together strips is wrapped on the carcass 2 of a tire being manufactured with one or more complete turns around the radial outer circumferential surface of the carcass. The end edges 5a, 5b of the belt band 5 are cut perpendicularly to the longitudinal axis thereof and are disposed to overlap each other with the amount of overlap ranging between 20 and 80 mm.