Building and shaping a tire

A tire building apparatus comprising:

• carcass shaping means having a first pair of end ring assemblies and three annular inflatable chambers;
• the first chamber thereof being defined by an outer wall and an inner wall each terminating axially in end rings located concentrically in the respectively associated one of said ring assemblies, both walls being of elastomeric material reinforced by cords extending axially between and into each respective end ring;
• the second and the third chambers thereof being disposed coaxially between said outer and said inner wall and each being defined by a cord-reinforced annular wall having a solid elastomer ring concentrically integral therewith disposed concentrically between and in circumferential contact with the respectively associated end rings of said inner and said outer wall in said assemblies, said second and said third chamber each having an axial length when not inflated not greater than one-third of the uninflated axial length of said first chamber;
• a pair of turnup means including a second pair of end ring assemblies disposed in coaxial abutting relation each respectively with the associated one of said first pair of end ring assemblies;
• each turnup means including an inner and an outer annular inflatable chamber, said outer chamber, having a cord-reinforced elastomeric membrane having two circular end rings, said inner chamber being defined by an annular membrane having a solid elastomeric circular ring integrally thereon, the latter said ring being disposed concentrically in contact with and between the associated two end rings of the outer chamber membrane to form one of the second pair of end ring assemblies;
• said inner chamber being disposed inside the outer chamber and at least approximately equal in uninflated axial length to the uninflated axial lengths of the second and the third chamber of said shaping means.

A tire building drum comprising, a circumferentially continuous first annular envelope axially continuous between two bead-locating planes and a pair of second annular envelopes disposed coaxially of said first envelope and extending oppositely outward respectively from said planes, the first and the second said envelopes cooperating to provide the cylindrical building surface of said drum;

• a pair of carrier means mounted for equal and opposite movement coaxially of said drum and a plurality of rigid segments mounted on each said carrier means for symmetric movement radially of the drum axis, each segment having a surface underlying said first envelope and the respectively associated second envelope and extending axially in each direction from the respective bead-locating plane not more than one-third of the axial dimension of said first envelope, said first envelope comprising an inner and an outer wall member co-operating to define therebetween a first inflatable annular chamber, said inner and said outer member being circumferentially connected to one another adjacent each respective bead-locating plane, a first pair of independently inflatable anular bladders disposed within said first chamber and connected respectively to said inner and said outer wall member close to the respective bead-locating planes, and a second pair of annular inflatable bladders disposed respectively within said second envelopes and concentrically connected respectively to said second envelopes adjacent to said bead-locating plane, each first annular bladder being cooperable with the associated second annular bladder to apply a circumferentially continuous squeeze to compress the bead region of the tire therebetween.

Tire building apparatus comprising:

• drum means providing a straight cylindrical building surface;
• shaft means rotatably supporting the drum means for rotation;
• center support means fixed coaxially and corotatably on said shaft means;
• a pair of carrier means slidably and corotatably disposed on said shaft means for axial movement symmetrically toward and away from each other between a building position and a shaping position;
• on each of said carrier means a plurality of clamping segments arranged to provide bead clamping rings in substantially continuous circular array mounted for symmetric movement radially of said shaft means, each of said segments extending axially from a respectively associated bead-locating plane a predetermined distance respectively toward and away from said center support means to provide two rigid cylindrical reaction surfaces;
• each of said segments having a slot open radially outwardly thereof and in circumferential alignment to form a pair of axially spaced apart grooves extending circumferentially of the respective bead clamping rings;
• bladder means defining said cylindrical band building surface and comprising:
• a pair of dual turnup bladders disposed circumferentially of each of said bead clamping rings and extending axially outwardly from the bead engagement plane bisecting the respectively associated dovetail or T-groove;
• each turnup bladder having a bead engagement ring disposed in the respectively associated dovetail or T-groove, an outer cord-reinforced membrane forming a first closed inflatable annular envelope attached to said bead engagement ring and extending in uninflated state axially outward therefrom;
• an inner cord-reinforced membrane forming a second closed inflatable annular envelope inside said first envelope and attached to said bead engagement ring and extending axially in uninflated state outwardly therefrom about one-quarter of the axial extent of said outer membrane in its uninflated state;
• and a shaping bladder disposed circumferentially of said clamp ring segments symmetrically of said center support means and extending axially in uninflated state from one to the other of said clamp rings, said shaping bladder having a pair of second bead seat rings disposed respectively in said dovetail or T-groove and respectively abutting the first bead seat rings of said turnup bladders;
• an inner cord-reinforced wall and an outer cord-reinforced wall each attached to and extending in uninflated state between said two second bead seat rings, the walls forming a closed inflatable annular envelope, a pair of inside bladders each forming a closed inflatable annular envelope attached to a respectively associated one of said second bead seat rings and extending axially about one-fifth to one-third the distance between said second bead seat rings toward the other thereof inside said shaping bladder envelope formed by said walls;
• said outer wall having an outer layer and an inner layer, and blade means disposed between and affixed to said inner and said outer layers for modifying the shape of said shaping bladder when inflated with respect to the inflated shape of said bladder absent such blade means;
• said blade means comprising a plurality of long narrow blades extending parallel to said shaft and equally spaced thereabout, each blade having near each end thereof a side extension projecting in a circumferential direction sufficiently to overlap a next adjacent blade, and each blade being thicker, in depth radially of the drum, at its mid-length and graduated to lesser thickness radially of the drum progressively axially outward toward its end portions;
• each of said clamp rings of segments being extendable radially of the drum means to engage at least one carcass ply between an endless inextensible bead core and one of each said first and said second bead seat ring in initial axially coplanar registry with said bead core;
• said shaping bladder being inflatable to shape said carcass ply from its cylindrical form as laid about said building surface to said toroidally shaped carcass form, said clamp rings being concurrently movable axially toward said shaping position;
• said inside bladders and said second annular envelopes when inflated cooperating after shaping said ply with respectively associated ones of said reaction surfaces to turn ends of said ply about the respectively associated bead cores and radially outwardly along respective carcass sidewalls and to compress and to consolidate the ply with circumferentially uniform pressure in the regions of the sidewalls close to said bead cores while said sidewalls extend radially of said bead cores at or about the orientation thereof to be had in the tire after it has been cured, whereby relative rotational movement of the bead core and the adjacent carcass ply can be avoided.

A method of building and shaping a tire comprising providing flat cylindrical surface means including a center envelope terminating in spaced planes normal to an axis and turnup bladders respectively abutting and extending oppositely outward coaxially from said envelope;

• forming a precarcass band in flat cylindrical form on said surface means;
• positioning a pair of preformed inextensible bead cores in radially and coaxially spaced relation to lie respectively in said planes and about said band;
• expanding said band first at circumferential locations respectively coplanar with the terminii of said envelope and with the bead cores to initiate conformation of the band about said bead cores;
• expanding portions of said band then at locations immediately adjacent to and respectively inward and outward of each bead core to roll said portions simultaneously progressively radially outward of each bead core to enclose at least partially each bead core respectively between said portions while moving said bead cores axially toward each other sufficiently only to accommodate such expansions;
• thereafter shaping said band with said envelope between said bead cores to a toroidal form having a shape ratio of radial height to axial width at least approximately that of the tire after the same has been cured by applying to said envelope radially outward pressure and by concurrently moving said bead cores toward each other to the spacing therebetween desired in the tire after curing the same;
• and subsequently completing and curing the tire.

A method of building and shaping a tire comprising:

• building a precarcass band on flat cylindrical surface means comprising a shaping envelope and a pair of turnup bladders coaxially abutting respectively the axial ends of the envelope;
• disposing a pair of tire bead cores in coaxially spaced relation around said band and expanding first regions of said band respectively coplanar with said bead cores to conform said regions to said cores;
• then conforming said band to said bead cores before shaping the remainder of said band by simultaneously inflating a pair of annular bladders respectively adjacent to the axially inward and the axially outward sides of each of said bead cores;
• said bladders adjacent the axially inward sides of the respective bead cores being fixed inside of and respectively to the axial ends of the envelope, said bladders adjacent to the axially outward sides of said bead cores being inside of and fixed respectively to the axial ends of the turnup bladders which respectively abut the envelope so that the bead cores are at least partially wrapped by said band before the band is shaped toroidally;
• then shaping said envelope to shape said band between said cores by pressurized air while moving said bead cores axially inward to the spacing therebetween desired in the tire after molding and curing the same;
• and controlling the toroidal shape of said envelope when the same is expanded, to a shape ratio of radial height to axial width which is at least approximately equal to the shape ratio of said tire when the same has been molded and cured;
• and subsequently completing and curing the tire.