Tire cure control system and method
First Claim
1. A method of controlling the cure of a rubber compound containing a reinforcing agent or filler, comprising the steps of closing a mold with the rubber compound therein, applying heat to the rubber compound to initiate curing of the rubber compound, passing a microwave signal through the rubber compound, measuring the attenuation of the microwave signal, calculating from the microwave attenuation measurements the rate of change of microwave attenuation, using the rate of change of microwave attenuation to determine when to issue a press opening signal, and automatically initiating a press opening sequence in response to the press opening signal.
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Accused Products
Abstract
A tire cure control system and method characterized by a computer-based data acquisition and process control unit that uses non-invasive, direct cure measurements to adjust the length of cure so that all cured articles such as tires will be cured to the same extent in the minimum amount of time, thereby to maximize production while providing uniformly cured products. The unit generally includes at least one microwave probe, although preferably multiple microwave probes, placed in the mold and a processor to process probe data and to initiate a control action principally initiating a mold opening sequence at the optimal time. Initiation of the mold opening sequence at least in part is based upon a measurement of the time rate of change of the attenuation of microwave energy caused by the curing rubber compound in the mold.
56 Citations
19 Claims
- 1. A method of controlling the cure of a rubber compound containing a reinforcing agent or filler, comprising the steps of closing a mold with the rubber compound therein, applying heat to the rubber compound to initiate curing of the rubber compound, passing a microwave signal through the rubber compound, measuring the attenuation of the microwave signal, calculating from the microwave attenuation measurements the rate of change of microwave attenuation, using the rate of change of microwave attenuation to determine when to issue a press opening signal, and automatically initiating a press opening sequence in response to the press opening signal.
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7. A method of vulcanizing a rubber tire in a closed mold having a generally toroidal mold cavity wherein a green tire is expanded in the mold by supplying a pressure fluid to the interior of the green tire, comprising the steps of:
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in a first stage, supplying high-pressure steam to the interior of the green tire to shape and heat the green tire; in a second stage, circulating hot media through the interior of the green tire by passing the hot media into and out of the interior of the green tire; in a third stage, shutting off outward flow of the hot media from the interior of the green tire while supplying the hot media to the interior of the green tire; and in a fourth stage, removing the hot media from the interior of the tire and opening the mold to permit removal of the tire; and wherein the first and second stages are of fixed duration and the duration of the third stage is based on a selected characteristic of the tire measured during the curing thereof, and wherein the selected characteristic is the rate of change of attenuation of a microwave signal passed through the tire. - View Dependent Claims (8)
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- 9. In a system for vulcanizing a rubber product containing a reinforcing agent or filler in a closed mold, comprising at least one microwave probe proximate the surface of the mold cavity and having an input and an output, means for applying a microwave signal to the input of said probe, means connected to the output of said probe for measuring the microwave signal at the output of said probe, and means for comparing the amplitudes of said microwave signal at the input and output of the probe and for calculating the rate of change of the attenuation of the microwave signal, whereby the rate of change of the attenuation of the microwave signal is determined for use in determining the state of cure of the rubber product.
- 16. A method of controlling the cure of a rubber compound containing a reinforcing agent or filler, comprising the steps of closing a mold with the rubber compound therein, applying heat to the rubber compound to initiate curing of the rubber compound, measuring a characteristic of the rubber compound having relation to the state of cure of the rubber compound by passing a microwave signal having a frequency of at least 1 Ghz through the rubber compound, determining from the measured characteristic an optimal time to initiate a press opening sequence, and automatically initiating a press opening sequence at the optimal time, and wherein the measured characteristic is the rate of change of attenuation of the microwave signal passed through the tire.
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19. A non-destructive quality assurance method for determining the state of cure of a rubber product containing a reinforcing agent or filler during curing thereof in a mold comprising the steps of (a) passing a microwave signal through the rubber product, (b) measuring the attenuation of the microwave signal, (c) calculating from the microwave attenuation measurements the rate of change of microwave attenuation, and (d) using the rate of change of microwave attenuation to obtain an indication of the state of cure of the rubber product.
Specification