Plastic article or earthenware shaping or treating: apparatus – Reshaping – resizing or vulcanizing means for tire – tire... – Toroidal or annular female shaping means and coacting means...
Reexamination Certificate
2000-06-29
2002-06-04
Mackey, James P. (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Reshaping, resizing or vulcanizing means for tire, tire...
Toroidal or annular female shaping means and coacting means...
C425S812000
Reexamination Certificate
active
06398533
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mold for a pneumatic tire, more particularly to a mold used with an inflatable bladder which is capable of minimizing air staying between the bladder and tire.
2. Description of Related Art
In general, during vulcanizing a pneumatic tire, as shown in
FIG. 8
, the inside of the green tire T in a mold (a) is pressured by a bladder (b) inflated by a heating and pressurizing medium. The bladder (b), during inflating, first contacts with the tread portion Tt and bead portion Tb, and as indicated by arrows f
1
and f
2
, the contact region expands toward the sidewall portion. Therefore, air (e) is liable to remain between the bladder (b) and green tire T in the sidewall portion especially near the shoulder portion Ts
1
. The remaining air (e) partially decreases pressure which presses the green tire T against the mold (a). Therefore, carcass cord tension decreases partially, and accordingly, cord elongations, cord spacings and cord directions are liable to become ununiform, which results in deterioration of tire performances such as steering stability, road noise, force variation, bulge/dent on the tire outside, rubber bare and the like.
SUMMARY OF THE INVENTION
It is therefore, an object of the present invention to provide a tire mold for use with a bladder which can minimize air between the bladder and green tire.
According to the present invention, a tire mold comprises a pair of bead rings, each of the bead rings provided with a bead bottom molding face for molding the bead bottom surface of the tire, and further each bead ring provided radially inside the bead bottom molding face with a protrusion protruding axially inwardly from the axially inner end of the bead bottom molding face so that the axial extent of the protrusion from the axially inner end of the bead bottom molding face is in the range of from 0.05 to 0.4 times the axial distance between the axially inner ends of the bead molding faces.
REFERENCES:
patent: 2025992 (1935-12-01), Laursen
patent: 2734225 (1956-02-01), Glynn
patent: 3278990 (1966-10-01), Joseph et al.
patent: 3563831 (1971-02-01), Clapp et al.
patent: 4028029 (1977-06-01), MacMillian
patent: 4035118 (1977-07-01), MacMillian
patent: 5078584 (1992-01-01), Drewel et al.
patent: 5961913 (1999-10-01), Haase
patent: 1231597 (1971-05-01), None
Hanya Masahiro
Ono Ryo
Sakamoto Masayuki
Yamamoto Emiko
Birch & Stewart Kolasch & Birch, LLP
Mackey James P.
Sumitomo Rubber Industries Ltd.
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