Cutting – Processes – With preparatory or simultaneous ancillary treatment of work
Reexamination Certificate
2002-08-23
2003-06-10
Shoap, Allan N. (Department: 3724)
Cutting
Processes
With preparatory or simultaneous ancillary treatment of work
C083S030000, C083S039000, C083S056000, C083S951000
Reexamination Certificate
active
06575064
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates to methods and apparatus for cutting elastomeric materials at low skive angles, in particular cutting layered composites of elastomeric materials including layers containing reinforcing materials.
2. Background of the Invention
Various methods and apparatus have been used for the cutting of sheets of elastomeric material. Such elastomeric material might consist of single sheets of homogeneous material, or multiple layered sheets of materials having properties that are different from one another. In the case of multiple layered sheets of elastomeric material that, for various reasons, need to be cut, one or more of the layers might contain reinforcing cords or fibers made of metal or fabric. Such reinforcing cords or fibers might be part of a woven reinforcing fabric, or they might be simply aligned in such a way as to be parallel to one another. Furthermore, the elastomeric materials that are to be cut may or may not be cured or vulcanized at the time of cutting.
Prior art cutting methods and apparatus include cutting wheels, ultrasonic cutters, scissor type cutters, guillotine knives, wire cutters and vibrating scroll cutters whose active cutting principle is a saw blade or a tensioned wire.
While such prior art cutting methods are effective to varying degrees, each as disadvantages. For example, the guillotine knife is somewhat effective in cutting composite elastomeric materials, but it has the disadvantage of having a tendency to deform the cut surfaces of the elastomeric material as the knife penetrates the material. Such deformation of the cut edge increases the difficulty of subsequent splicing the ends of the elastomeric material. Moreover, the guillotine knife produces a continually degraded cut surface as the blade becomes dull and/or as small pieces of elastomer began to build up on the blade. Yet another disadvantage was the inability of the blade to cut at an angle less than 30 degrees relative to the plane of the material being cut. The guillotine blade also tends to generate heat during the cutting process such that, as numerous cuts are made, the temperature of the knife becomes sufficiently elevated in some cases to induce precuring of unvulcanized elastomer in the region of the cut, which then inhibits subsequent proper splicing the cut edges.
Another prior art cutting system and method, disclosed in U.S. Pat. No. 5,638,732, employs a cutting wire. This system could not, however, be used to cut preassembled elastomeric composite sheets containing reinforcing cords because the reinforcing cords themselves, though aligned more or less parallel to the direction of the cut, get severed. This deficiency is actually inherent to nearly every prior art cutting technology (including ultrasonic knives) that cut composite elastomeric preassemblies at relatively low skive angles. That is to say, nearly all prior art cutting methods tended to cut the parallel-aligned cords that are used to reinforce one or more layers of reinforced ply. (The cut is, ideally, intended to be made between the parallel-aligned reinforcing cords.) The only prior art exception being the scroll cutter, which could cut at low skive angles without also risking cutting the reinforcing cords.
The scroll cutter cannot, however, initiate its cut within the central region of a sheet of preassembled composite elastomeric sheets, because of its geometry, which includes a wire held at each end by a fixture. The scroll cutter must start its cut from the side of the preassembly, such that the cutting has difficulty entering the ply without splitting the reinforcing cords. Even at a 90 degree skive angle, the reliability of not splitting cords is in question. At low skive angles it becomes exponentially difficult to enter the ply without splitting a ply cord. Sometimes the reinforced ply end will be buried under the other layers, such as, in the case of tire manufacturing, the sidewall layer or other layers such as the extreme edge of the preassembly within the context of envelope construction. This adds another dimension of difficulty for the wire scroll cutter to cut reliably preassembly with reinforced layers, such as specifically the ply of tires.
Ultrasonic cutting systems as disclosed in U.S. Pat. No. 5,265,508, can cut stock material at low skive angles. However, they require that the material be secured to an anvil during cutting.
Another system, disclosed in U.S. Pat. No. 4,922,774, employs an ultrasonic cutting device which vibrates a knife that moves across an elastomeric strip. However, this system is limited to cutting angles of between 10 and 90 degrees, and it does not provide for cutting between parallel disposed, reinforcement cords within the strip, which is to say, the cords can get cut.
A significant problem with the prior art cutting systems and methods is the inability to cut at angles less than 30 degrees relative to the plane of the elastomeric layers being cut without deformation or precuring the material. This can be a problem in, for example, automated tire building operations wherein the cutting has to be done precisely and quickly and where the cutter can also provide improvements to the cut surface which is subsequently to be spliced.
An ideal cutting method and apparatus should be able to make cuts at low angles (relative to the plane of the elastomeric sheet being cut), and it should be able to do so without cutting the parallel-aligned reinforcing cords between which the cutter is ideally to move. It should also be able to make these low angle cuts rapidly and reliably.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide method and apparatus for cutting single or multilayered flat sheets of elastomeric materials, one or more layers of which are reinforced with cords which are aligned parallel to one another and oriented in the direction of the cut, the method and apparatus being as defined in one or more of the appended claims and, as such, having the capability of being constructed to accomplish one or more of the following subsidiary objects.
One object of the present invention to provide a method and apparatus for cutting segments of cord-reinforced elastomeric material from long, multilayered flat sheets of cord-reinforced elastomeric material, such method and apparatus overcoming the disadvantages and limitations of the prior art methods and devices.
Another object of the present invention to provide a method and apparatus for cutting segments of material from long multilayered flat sheets of cord-reinforced elastomeric material without cutting the reinforcing cords that are more or less aligned with the direction of the cut.
It is another object of the present invention to provide a method and apparatus for cutting segments of material from long multilayered flat sheets of cord-reinforced elastomeric materials by initiating the cut at a location that is between the lateral edges of the sheet of elastomeric material.
Yet another object of the present invention to provide a method and apparatus for initiating the cutting segments of material from multilayered flat sheets of cord-reinforced elastomeric materials without cutting the reinforcing cords.
Another object of the present invention to provide a method and apparatus for cutting segments of material from long multilayered flat sheets of cord-reinforced elastomeric materials by the controllable penetration of the cutting knifes such as to perform the cutting in a such a way that intentionally dulled edges of the cutting knives are in close proximity to the reinforcing cords, thereby protecting the reinforcing cords from being cut.
Another object of the present invention is to provide a method and apparatus for cutting segments of material from long multilayered flat sheets of cord-reinforced elastomeric materials at skive or cutting angles that can be varied between angles of about 5 degrees and about 40 degrees with respect to the plane of the sheet.
Still another object of the present invention to provide method and appar
Benzing, II James Alfred
Hart James Michael
Cohn Howard M.
Hamilton Isaac
Shoap Allan N.
The Goodyear & Rubber Company
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