Abstract:
A green tyre disposed on a toroidal support is introduced into a vulcanisation mould. The mould is closed through axial approaching of a pair of sidewall plates acting against the sidewalls of the tyre. Circumferential sectors set to operate against the tyre tread band are maintained spaced apart from the tread band itself during admission of a working fluid designed to press the tyre against the toroidal support. Subsequently, the sectors are centripetally approached for penetration into the tread band concurrently with a step of full moulding and vulcanisation of the tyre carried out through admission of steam under pressure into the tyre itself.
Abstract:
A method of moulding and curing tyres for vehicle wheels includes the steps of disposing a tyre being processed on a toroidal support, enclosing the tyre and the toroidal support inside a moulding cavity defined in a vulcanization mould, pressing the outer surface of the tyre against the moulding cavity walls, and administering heat to the tyre to cause molecular crosslinking of the tyre. The pressing step includes the steps of compressing side portions of the tyre between the moulding cavity walls and the outer surface of the toroidal support, concurrently with the closing step, and imposing an expansion to a radially-outer portion of the tyre to bring the radially-outer portion of the tyre against the walls of the moulding cavity.
Abstract:
A tire mold 2 for curing new or retreaded tires 20 has an upper platen 4, a lower platen 6, and a central rim 30 with a frangible member 50 designed to open when a predetermined pressure P1 in excess of the normal curing pressure Pc is observed. The frangible member 50 preferably includes a rupture disk 60 that breaks upon exposure to the pressure P1.
Abstract:
A process for manufacturing, moulding, and curing a tire includes the steps of manufacturing a tire comprising a first elastomer material, providing an inner surface of the tire with a treatment to prevent permeation of a fluid under pressure through the treatment, closing the tire into a moulding cavity defined in a vulcanization mould, admitting a fluid under pressure into a space defined by the treatment in order to press an outer surface of the tire against the at least one wall of the moulding cavity, and applying heat to the tire to vulcanize the first elastomer material. A shape of the at least one wall of the moulding cavity matches a shape of the outer surface of the tire after vulcanization is complete. The treatment includes at least one layer of a second elastomer material having a sulfur-curable polymeric base and a vulcanizing system dissolved in an organic solvent.
Abstract:
An apparatus for forming curing envelopes which apparatus enables the use of a conventional inner tube mold for making a curing envelope preform in the form of an envelope tube which may have a portion thereof easily removed to provide a curing envelope suitable for use in a tire retreading process. A curing envelope is made by placing an annular tube of uncured envelope material in a curing mold having a center core and a mold insert installed therein. The insert includes a pair of coaxial annular rings projecting radially outwardly from the center core and connecting straps for maintaining the axial spacing between the rings. The mold is closed and heat and internal pressure are applied to the envelope tube for curing the envelope tube and urging the tube against the interior cavity surface with the annular rings penetrating into the inner wall of the tube for forming therein corresponding annular grooves. The mold is then opened and the envelope tube is removed from the mold after which the envelope tube is severed along the annular grooves to remove the portion of the inner wall of the envelope tube between the grooves thereby to form a curing envelope of generally U-shape cross-section.
Abstract:
A bladder for use in a tire molding and vulcanization press has grooves in its outer face and a circumferential molding flash on its inner face. A process for the manufacture of this membrane by molding uses a press having a ribbed core to produce the grooves and two shells which may have smooth walls.
Abstract:
This disclosure relates to a retreading mold which includes a pair of relatively movable platens, means for supporting the platens during relative movement therebetween, means for imparting relative motion to the platens between spaced open and closed positions thereof, a matrix carried by each platen, the motion-imparting means including a reciprocal member, and means between the reciprocal member and one of the platens for effecting self-centering between the platens in the closed position thereof, the self-centering means preferably being defined by a curved surface between one platen and the reciprocal member.
Abstract:
This disclosure relates to retread molds adapted for manual, semi-automatic, or full automatic operation particularly in bag or bladder retreading operations, and includes the following novel features:A. bead aligner wheels with circular continuous uninterrupted sealing ribs for forming annular chambers in conjunction with an associated bladder which upon pressurization of the latter results in a partial vacuum in the chambers such that the bladder will be maintained as desired during opening and closing of the matrices as well as relative movement between the bead aligner wheels;B. bladder locating means on the bead aligner wheels for centering the bladder and projections on the bead aligner wheels for preventing bladder pinching;C. cooperative means on the exterior surface of the bladder and the bead aligner wheels for venting air from between the bladder and an associated tire to atmosphere;D. port means in beads of the bladder for permitting the introduction of fluid into and the withdrawal of fluid from the interior of the bladder;E. means for achieving self-centering between a pair of relatively movable platens carrying the matrices and bead aligner wheels;F. the provision of a reservoir or sump in connection with a rotatable screw for lubricating the latter during opening of the platens, andG. a novel method of foreshortening the diameter of a tire prior to the closing of full circular matrices during a retreading operation.
Abstract:
This disclosure relates to retread molds adapted for manual, semi-automatic or full automatic operation and specifically is directed to a pair of relatively movable platens carrying matrix means for receiving a tire therein with bead aligner wheels associated therewith, the bead aligner wheels being in axially opposed relationship to each other, an annular bladder disposed between the platens, the annular bladder having innermost peripheral marginal portions, the marginal portions being in overlying relationship upon the bead aligner wheels, and means for creating an annular gap between a terminal edge of each bladder peripheral marginal portion, an outboard portion of each of the bladder peripheral margins and the associated bead aligner wheel, the annular gap creating means being defined by an annular bead carried by each outboard portion and/or terminal end of each bladder peripheral marginal portion in sealing contact with its associated bead aligner wheel.