BLADDER, AN APPARATUS AND A METHOD FOR SHAPING AND CURING A TIRE
First Claim
1. A bladder for shaping and curing a green tire comprising an endless ribbon of elastomeric membrane, the ribbon comprising a main circumferential portion which comes into contact with the cavity of the tire upon full inflation of the bladder and two circumferential edges which are adapted to be fastened to two axially opposite flanges of a tire mold, respectively;
- wherein the membrane of the main circumferential portion of the ribbon is structurally weakened in two circumferential strip-like regions, the rigidity of the membrane at the remaining regions of the main circumferential portion being higher than at the two structurally weakened circumferential strip-like regions, in such a way that the two structurally weakened circumferential strip-like regions are able, upon inflation of the bladder, to stretch substantially more than the remaining regions.
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Accused Products
Abstract
A method, a bladder and an apparatus for shaping and curing a tire, wherein the bladder has two weakened regions corresponding to the shoulder regions of the tire when the bladder is expanded in the cavity of the tire. Upon inflation of the bladder and its expansion in the tire, the bladder contacts first the inner surface of the cavity at the bead regions and progressively the sidewalls, the shoulders and then the center of the tire. The weakened regions are designed to stretch more under a given tension than the remaining regions in order to allow a progressive contact movement of the lateral regions of the bladder with the sidewalls with very little tension and relative movement between the lateral regions of the bladder and the sidewalls of the tire.
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Citations
20 Claims
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1. A bladder for shaping and curing a green tire comprising an endless ribbon of elastomeric membrane, the ribbon comprising a main circumferential portion which comes into contact with the cavity of the tire upon full inflation of the bladder and two circumferential edges which are adapted to be fastened to two axially opposite flanges of a tire mold, respectively;
- wherein the membrane of the main circumferential portion of the ribbon is structurally weakened in two circumferential strip-like regions, the rigidity of the membrane at the remaining regions of the main circumferential portion being higher than at the two structurally weakened circumferential strip-like regions, in such a way that the two structurally weakened circumferential strip-like regions are able, upon inflation of the bladder, to stretch substantially more than the remaining regions.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus for shaping and curing a green tire, comprising
a tire mold comprising at least two axially opposite circumferential anchoring flanges; -
a tire bladder comprising an endless ribbon of elastomeric membrane, the ribbon comprising a main circumferential portion which comes into contact with the cavity of the tire upon full inflation of the bladder and two circumferential edges being fastened to the two axially opposite anchoring flanges, respectively; wherein the membrane of the main circumferential portion of the ribbon is structurally weakened in two circumferential strip-like regions, the rigidity of the membrane at the remaining regions of the main circumferential portion being higher than at the two structurally weakened circumferential strip-like regions, in such a way that the two structurally weakened circumferential strip-like regions are able, upon inflation of the bladder, to stretch substantially more than the remaining regions. - View Dependent Claims (12, 13, 14, 15)
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16. A method for shaping and curing a green tire, the method comprising the steps of:
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providing a mold comprising a bladder, the bladder comprises an elastomeric membrane; putting a green tire into the mold, the tire comprising an inner surface forming a cavity; inflating the bladder so that the bladder expands in the cavity of the tire;
curing said tire;wherein the elastomeric membrane of the bladder is weakened in those regions which come into contact with the shoulder portions of the tire cavity when the bladder is fully inflated in the tire cavity, the rigidity of the membrane in the regions coming into contact with the remaining portions of the tire cavity when the bladder is fully inflated being higher than at those regions coming into contact with the shoulder portions. - View Dependent Claims (17, 18, 19, 20)
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Specification