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TIRE MOLDING SYSTEM
Patent Pending – Serial # 11/505,765
TECHNICAL FIELD
In general, the present invention relates to a tire molding system. More particularly, the present invention relates to a method of molding tires where a texture is applied to a surface of the tire. Most particularly, the present invention relates to a method of molding tires, wherein a fine texture is applied to at least the sidewall of the tire during molding to enhance easthetics, conceal blemishes, and dissipate gas generated by the molding process.
BACKGROUND OF THE INVENTION
To manufacture a pneumatic tire, a raw tire is vulcanized in a mold. Typical tire molds are constructed of steel or aluminum. Heat is applied to the mold and transferred to the raw or "green" tire to form the tread and sidewall surfaces. To form these surfaces, the raw tire typically is in close contact with the interior surface of the mold. This close contact requires the venting of gases generated during the molding process. If these gases are not adequately released, they become trapped and create imperfections in the finished tire.
To that end, it is common to provide vents in the mold to release gas generated during molding. These vents typically take form of narrow tubular passages that extend outwardly of the mold. These vents may be referred to as mini vents in the art. Scratch vents are vents that direct gases to an interface between parts of the mold allowing the gas to escape through the gap created by the interface. Scratch vents are often formed near the bead ring portion of the tire mold. For sake of simplicity, mini vents and scratch vents will be collectively referred to as "vents" throughout this application.
In most molds, numerous vents are used to release gas. This is true even in mold systems that use vacuum, die casting, and other methods. During molding, material flows into these passages forming small protrusions on the surface of the finished tire. These protrusions are often referred to as "sprew" and generally detract from the appearance of the tire. At times the sprew will break off in the vents creating a service issue in that the vents must be kept clear to perform their function.
Even with vents present, gas may still become trapped against the surface of the raw tire resulting in imperfections in the surface of the finished tire. These imperfections may be removed during subsequent machining processes adding additional cost and time needed to manufacture the tire. It will be understood that these imperfections may detract from the appearance of the tire to the extent that the tire cannot be sold and must be scrapped.
It has also been common to decoratively configure the sidewall of the tire, but the decoration of the tire has been limited. Inlays to effect a "white sidewall," raised letters and the like have all been employed. However, regardless of the decorative means, the sidewall itself has generally been smooth and uniform, interrupted only by decorative features as mentioned above. More recently, "serrations" have been used to create decorative patterns on the sidewall of the tire. Serrations are raised parallel lines formed on the sidewall by a series of grooves cut into the mold by a CNC machine. Since the patterns are formed by a series of parallel lines, the designer is limited in terms of the forms that can be created. No attempt has been made to add decoration to the entirety of the tire, or specific parts of the tire such as the sidewall, treads, buttresses, or grooves of the tire or portions thereof as by texturing or the like.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved tire molding system that provides any of a multitude of decoration to the sidewall, buttress, grooves, or tread, while limiting or eliminating the need for venting.
In view of this object, the present invention provides a method of molding a tire including the steps of providing a mold having an interior surface, where the interior surface includes at least a buttress portion, a tread portion and a sidewall portion; defining a texture on at least one of the said portions, providing a raw tire in the mold and heating it to form a finished tire, channeling gases generated during molding through the texture.
The present invention further provides a method of molding a tire including the steps of providing a tire mold having an interior surface, defining a texture on a substantial portion of the interior surface, defining a vent hole in the interior surface opening externally of the mold, and fluidly connecting the vent hole to the texture.
The present invention further provides a method of molding a tire including the steps of providing a tire mold having an interior surface adapted to mold a raw tire placed within the mold, dissipating gases formed as the raw tire is heated through a texture formed in the interior surface.
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