Metal working – Method of mechanical manufacture – Disassembling
Reexamination Certificate
1999-04-19
2001-09-25
Mackey, James P. (Department: 1722)
Metal working
Method of mechanical manufacture
Disassembling
C029S428000, C425S046000, C425S047000, C425S195000
Reexamination Certificate
active
06292993
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vulcanizing machine for manufacturing pneumatic tires and, in particular, to a vulcanizing machine that is provided with an exchangeable segmented mold for selectively producing tires of different sizes or specifications.
2. Description of the Related Art
In the tire industry, it is a recent trend to use vulcanizing machines with segmented molds for manufacturing pneumatic tires, in particular high performance radial tires. Typically, a segmented mold includes a plurality of tread mold pieces for defining the outer contour of a tire tread portion, and upper and lower side mold members engaged with the tread mold pieces, for defining the outer contours of tire sidewall portions. The tread mold pieces are detachably connected to respective connector segments which are slidably engaged with a container ring so that vertical movement of the container ring causes radial movement of the connector segments relative to the tread mold pieces. Such segmented mold is disclosed, for example, in U.S. Pat. Nos. 4,872,822 and 4,883,415.
In order to achieve a satisfactory manufacturing productivity of tires, however, known vulcanizing machine requires further improvement. Specifically, besides a complicated structure arising from a large number of associated components and a high initial cost, there is a serious a problem that substantial labor and time are required for manually assembling or disassembling the segmented mold when, for example, changeover is to be effected in respect of size or specification of tires to be manufactured. Moreover, because the assembly or disassembly of the segmented mold is manually carried out within the vulcanizing machine, it is often necessary to wait the required operations until the vulcanizing machine has been sufficiently cooled down, which involves considerable loss time and waste of the heat energy which had been supplied to the vulcanizing machine and used for previous vulcanizing steps.
DISCLOSURE OF THE INVENTION
It is therefore an object of the present invention to eliminate the above-mentioned problems of the conventional vulcanizing machine.
It is another object of the present invention to provide an improved vulcanizing machine with an exchangeable segmented mold which can be installed into the machine or removed therefrom in a facilitated manner.
It is still another object of the present invention is provide an improved method for exchanging a segmented mold of a vulcanizing machine, wherein the segmented mold can be installed into the machine or removed therefrom within a significantly reduced time, thereby making it possible to readily perform the changeover in size or specification of the tires to be produced by the vulcanizing machine and thereby achieving a marked improvement in the manufacturing productivity.
According to one aspect of the present invention, there is provided a method of exchanging a segmented mold of a vulcanizing machine for producing pneumatic tires, wherein the segmented mold is of a type which comprises a plurality of tread mold pieces for defining an outer contour of a tire tread portion, said tread mold pieces each having an outer peripheral surface, and upper and lower side mold members engaged with said tread mold pieces, for defining respective tire sidewall portions, and wherein said vulcanizing machine further comprises a plurality of connector segments detachably connected to said outer peripheral surfaces of the respective tread mold pieces, said connector segments each having a tapered portion on back sides thereof, a container ring having a tapered surface which is slidably engaged with said tapered portions of the connector segments such that an axial movement of the container ring in the axial direction of the vulcanizing machine causes a radial movement of said connector segments relative to said tread mold pieces, and a top plate detachably connected to said upper side mold member.
The method according to the present invention comprises the step of removing a first segmented mold for tires of a first size, which is comprised of first tread mold pieces, a first upper side mold member and a first lower side mold member, from the vulcanizing machine in its non-operative condition, after disconnecting the connector segments from the respective first tread mold pieces while moving the container ring upwards such that the connector segments are moved radially outwards and disconnected from the respective first tread mold pieces, and disconnecting the top plate from the first upper side mold member.
The method according to the present invention further comprises the step of installing a second segmented mold for tires of a second size, which is comprised of second tread mold pieces, a second upper side mold member and a second lower side mold member, onto the vulcanizing machine, after placing the second mold into the vulcanizing machine, centering the second mold with reference to said vulcanizing machine, moving the container ring downwards such that the connector segments are moved radially inwards relative to the second tread mold pieces and are connected to the respective second tread mold pieces, and connecting the top plate to the second upper side mold member.
According to another aspect of the present invention, there is provided a vulcanizing machine for producing pneumatic tires, comprising: upper and lower holders; upper and lower side mold members for defining respective the sidewall portions, said upper side mold member being detachably connected to said upper holder through a top plate, and said lower side mold member being detachably connected to said lower holder; a plurality of tread mold pieces for defining an outer contour of a tire tread portion, said tread mold pieces each having an outer peripheral surface and being engaged with said upper and lower side mold members; a plurality of connector segments detachably connected to said outer peripheral surfaces of the respective tread mold pieces, said connector segments each having a tapered portion on back sides thereof; a container ring having a tapered surface which is slidably engaged with said tapered portions of the connector segments such that an axial movement of the container ring causes a radial movement of said tread mold pieces; clamp means for detachably connecting said upper side mold member to said top plate; and actuator means for moving said upper holder toward and away from said upper side mold member together with said top plate connected thereto.
REFERENCES:
patent: 4580959 (1986-04-01), Pizzorno et al.
patent: 4872822 (1989-10-01), Pizzorno
patent: 4883415 (1989-11-01), Salvadori
patent: 5118269 (1992-06-01), Klose et al.
patent: 5234326 (1993-08-01), Galli et al.
patent: 24 20 404 A1 (1975-11-01), None
patent: 324 00 591 A1 (1985-07-01), None
patent: 0 701 894 A2 (1996-03-01), None
patent: 1 248 891 (1971-10-01), None
Goto Tomotaka
Ito Taizo
Nagata Masami
Bridgestone Corporation
Mackey James P.
Oliff & Berridge PLC.
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