US4230649A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for continuous tread production
Assignee: Bridgestone Research LLC
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Filing: 1978-06-12
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Granted: 1980-10-28
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Expires: 1998-06-12
Abstract
Abstract An apparatus and processes for the production of a continuous rubber strip which is molded with surface designs, such as tire treads, in the uncured state and then cured, after removal from the mold, by heat or radiation is disclosed. In the apparatus the extruded rubber strip is passed between cooperating mold segments carried by respective endless belts which, along with related components, apply suitable temperatures and pressures to the strip to produce the surface designs. The molded uncured rubber strip is removed from the molds and then completely cured by radiation and/or heat. Process embodiments are also disclosed wherein partial curing of the rubber while in the molding apparatus is performed.
Inventors
- 👤 George G. A. Bohm
- 👤 Stanley S. Gross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:26
CPC Classifications
B; B29; B29D; B29D30/00; B29D30/06; B29D30/52; B29D30/54
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
127 words
A method for producing a continuous rubber strip with a surface design comprising the steps of: extruding uncured rubber into a continuous strip at a temperature below its curing temperature; impressing a design on said continuous strip by passing said strip between moving cooperating mold segments while impressing a high pressure of about 1000 psi to force the rubber into the design pattern of the mold at a temperature below the curing temperature of the rubber; maintaining a lower pressure on said strip after the imposition of said high pressure while said strip remains between said cooperating mold segments; removing the molded strip in the uncured state from between the moving mold segments; and curing the rubber of the molded strip after removal from the mold segments.
Claim 2
Independent Claim
127 words
A method for producing a continuous rubber strip with a surface design comprising the steps of: extruding uncured rubber into a continuous strip at a temperature below its curing temperature; impressing a design on said continuous strip by passing said strip between moving cooperating mold segments while impressing a high pressure of about 1000 psi to force the rubber into the design pattern of the mold at a temperature below the curing temperature of the rubber; maintaining a lower pressure on said strip after the imposition of said high pressure while said strip remains between said cooperating mold segments; removing the molded strip in the uncured state from between the moving mold segments; and curing the rubber of the molded strip after removal from the mold segments.
Claim 3
Dependent Claim
15 words
A method of claim 1 wherein the curing of the rubber is accomplished by radiation.
Claim 4
Dependent Claim
21 words
The method of claim 1 wherein the curing of the rubber is accomplished by partial radiation curing and partially heat curing.
Claim 5
Dependent Claim
27 words
The method of claim 1 comprising the further step of applying a release agent to said strip to facilitate its removal from between the moving mold segments.
Claim 6
Dependent Claim
27 words
The method of claim 1 further comprising the step of applying a release agent to the moving mold segments to facilitate the release of said strip therefrom.
Claim 7
Dependent Claim
21 words
The method of claim 1 wherein said lower pressure is in the range from ambient to just below said high pressure.
Claim 8
Dependent Claim
19 words
The method of claim 1 wherein a sulfur package is added to the rubber of said strip before molding.
Claim 9
Dependent Claim
27 words
The method of claim 1 comprising the further step of spraying the back of the uncured molded strip with a solution of a sulfur package before curing.
Claim 10
Dependent Claim
17 words
The method of claim 1 comprising the further step of trimming the uncured molded strip before curing.
Claim 11
Dependent Claim
17 words
The method of claim 1 comprising the further step of cooling the uncured molded strip before curing.
Claim 12
Dependent Claim
18 words
The method of claim 1 comprising the further step of preheating the strip before impressing the design thereon.
Claim 13
Independent Claim
152 words
A method for producing a continuous rubber strip with a surface design comprising the steps of: extruding uncured rubber compounded with a heat curing agent into a continuous strip at a temperature below the curing temperature of the rubber; after extrusion, heating said continuous strip uniformly to a temperature sufficient to induce partial curing throughout the uncured rubber; before the onset of cure in the rubber, impressing a design on said heated continuous strip by passing said strip between cooperating mold segments moving therewith while impressing a high pressure of about 1000 psi to force the rubber into the design pattern of the mold; maintaining a lower pressure on said strip after the imposition of said high pressure while partial curing is occurring in the rubber and said strip remains between said cooperating mold segments; completing curing of the rubber throughout the molded strip by heat after removal from the mold segments.
Claim 14
Independent Claim
152 words
A method for producing a continuous rubber strip with a surface design comprising the steps of: extruding uncured rubber compounded with a heat curing agent into a continuous strip at a temperature below the curing temperature of the rubber; after extrusion, heating said continuous strip uniformly to a temperature sufficient to induce partial curing throughout the uncured rubber; before the onset of cure in the rubber, impressing a design on said heated continuous strip by passing said strip between cooperating mold segments moving therewith while impressing a high pressure of about 1000 psi to force the rubber into the design pattern of the mold; maintaining a lower pressure on said strip after the imposition of said high pressure while partial curing is occurring in the rubber and said strip remains between said cooperating mold segments; completing curing of the rubber throughout the molded strip by heat after removal from the mold segments.
Claim 15
Independent Claim
185 words
A method for producing a continuous rubber strip with a surface design comprising the steps of: extruding uncured rubber compounded with a heat curing agent into a continuous strip at a temperature below the curing temperature of the rubber; impressing a design on said heated continuous strip by passing said strip between cooperating mold segments moving therewith while impressing a pressure of about 1000 psi to force the rubber into the design pattern of the mold; heating the mold surfaces to a temperature sufficient to induce partial curing of the surface portion of the rubber strip in contact with the mold surface; before the onset of surface curing in the rubber releasing the pressure of about 1000 psi and maintaining a lower pressure on said strip after the imposition of said 1000 psi pressure while partial curing is occurring in the surface of the rubber and said strip remains between said cooperating mold segments; removing the molded strip with the partially cured surface from between the moving mold segments; and completing curing of the rubber throughout the molded strip after removal from the mold segments.
Claim 16
Independent Claim
185 words
A method for producing a continuous rubber strip with a surface design comprising the steps of: extruding uncured rubber compounded with a heat curing agent into a continuous strip at a temperature below the curing temperature of the rubber; impressing a design on said heated continuous strip by passing said strip between cooperating mold segments moving therewith while impressing a pressure of about 1000 psi to force the rubber into the design pattern of the mold; heating the mold surfaces to a temperature sufficient to induce partial curing of the surface portion of the rubber strip in contact with the mold surface; before the onset of surface curing in the rubber releasing the pressure of about 1000 psi and maintaining a lower pressure on said strip after the imposition of said 1000 psi pressure while partial curing is occurring in the surface of the rubber and said strip remains between said cooperating mold segments; removing the molded strip with the partially cured surface from between the moving mold segments; and completing curing of the rubber throughout the molded strip after removal from the mold segments.
Claim 17
Dependent Claim
14 words
The method of claim 11 wherein the strip is preheated to about 120° C.
Claim 18
Dependent Claim
15 words
The method of claim 1, wherein the mold segments are heated to about 120° C.
Claim 19
Dependent Claim
27 words
The method of claim 1 further comprising the step of interposing a meltable strip film between said strip and the design pattern in said block mold segments.
Claim 20
Dependent Claim
34 words
The method of claim 16 further comprising the steps of heating said meltable strip to above its melting temperature before said interposition; and cooling said meltable strip to below its melting temperature while interposed.
Claim 21
Independent Claim
25 words
The method of claims 1, 12, or 13 wherein the lower pressure is maintained on the strip for a longer time than the high pressure.
Claim 22
Independent Claim
20 words
The method of claims 1, 12, or 13 wherein the mold segments are moved at about 6 feet per minute.
Claim 23
Independent Claim
16 words
The method of claims 12 or 13 wherein said heat curing agent comprises a sulfur package.
Claim 24
Dependent Claim
25 words
The method of claim 20 wherein said sulfur package contains between 50 to 100% of constituents normally used for a full cure of the rubber.
Claim 25
Independent Claim
172 words
A method for producing a continuous rubber strip with a surface design, such as a tire tread, thereon comprising the steps of: extruding uncured rubber into a continuous strip at a temperature of about 100° C.; preheating said continuous strip to a temperature in the range between 120° C. to just below its curing temperature to soften said rubber; impressing a design on said continuous strip by passing said strip between moving cooperating mold segments while impressing a high pressure of the order of 1000 psi to force the rubber into the design pattern of the mold at a temperature below the curing temperature of the rubber; maintaining a lower pressure, in the range from ambient to just below said high pressure, after the imposition of and for a longer time than said high pressure while said strip remains between said cooperating mold segments; removing the molded strip in the uncured state from between the moving mold segments; and curing the rubber of the molded strip after removal from the mold segments.
Claim 26
Independent Claim
172 words
A method for producing a continuous rubber strip with a surface design, such as a tire tread, thereon comprising the steps of: extruding uncured rubber into a continuous strip at a temperature of about 100° C.; preheating said continuous strip to a temperature in the range between 120° C. to just below its curing temperature to soften said rubber; impressing a design on said continuous strip by passing said strip between moving cooperating mold segments while impressing a high pressure of the order of 1000 psi to force the rubber into the design pattern of the mold at a temperature below the curing temperature of the rubber; maintaining a lower pressure, in the range from ambient to just below said high pressure, after the imposition of and for a longer time than said high pressure while said strip remains between said cooperating mold segments; removing the molded strip in the uncured state from between the moving mold segments; and curing the rubber of the molded strip after removal from the mold segments.
Claim 27
Dependent Claim
20 words
The method of claim 22 wherein the preheating step is performed by heating the mold segments to about 120° C.
Claim 28
Dependent Claim
15 words
The method of claim 22 wherein the preheating step is performed with a microwave oven.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-28 | 1984-04-28 | 1984-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-28 | 1988-04-28 | 1988-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-28 | 1992-04-28 | 1992-10-28 | $7700.00 | Window Closed / Lapsed |