Textiles: cloth finishing – Expanding device for textile webs – Spreader
Reexamination Certificate
2000-02-22
2001-02-13
Vanatta, Amy B. (Department: 3741)
Textiles: cloth finishing
Expanding device for textile webs
Spreader
C026S071000
Reexamination Certificate
active
06185800
ABSTRACT:
The present invention relates to the art of spreading a reenforcing cord containing fabric preparatory to application of rubber to the fabric in a calender line and more particularly to a spreader and system using the spreader for controlling the width of fabric before entering a calender that rubberizes the fabric to produce sheet material used in the production of tires.
INCORPORATION BY REFERENCE
Incorporated by reference herein is Bulletin No. 10191 from North American Manufacturing Company entitled Calendar Lines “Total Concept” dated April 1991. This trade bulletin discloses a well known calender line for producing laminating fabric to be used in the manufacturing of tires. Disclosed herein are a number of devices for spreading the fabric which is formed from longitudinally extending, reenforcing cords spaced laterally across the fabric between two spaced edges. The fabric moves in a given path through the spreading devices and processing steps on its way to the calender where it is rubberized. This type of production line is well known and has been used for over quarter of a century. Bulletin No. 10191 is incorporated by reference herein to show the environment to which the present invention is directed which is a spreading mechanism located immediately before the calender where the fabric is encased in non-vulcanized rubber for production of tires.
BACKGROUND OF INVENTION
In the tire and rubber industry calender lines process “gray” fabric for the purpose of producing laminate sheets used to construct rubber tires. The fabric includes longitudinally extending reenforcing cords spaced laterally across the fabric between two transverse edges, which cords are held together by transversely extending picks including small strands or threads spaced longitudinally of the fabric. The fabric is unrolled and then treated in the calender line in a manner that requires periodic spreading of the fabric to a width which is carefully controlled as the fabric enters the calender. The tire cord fabric is produced with various cord counts per inch across the fabric, i.e, cord distribution. In some instances, the cord count or distribution is as low as twelve cords per inch; however, it can be as high as thirty cords per inch. These fabric cords are held together by the picks, which are woven perpendicular in the cords and spaced along the fabric with 2-3 picks per linear inch of cord. From a quality standpoint, the objective is to have the desired cord count extending uniformly over the entire width of the fabric before the fabric is introduced into the calender. However this even distribution of the cords is not accomplished in calender lines now in use. The fabric has a tendency to neck down as it travels toward the calender; therefore, the fabric must be respread several times in the calender line. Spreading devices heretofore used are not predicated on the cord count. As the fabric is respread periodically during its travel through the line, a greater number of cords remain bunched at the edges because the spreading devices are ineffective in spreading this portion of the fabric. Thus, a high concentration of cords appear adjacent the edges of the fabric as the fabric enters the calender for rubberization even though the fabric has the proper width. After processing by the calender, the edge portions of the fabric must be removed by a continuous cutting operation that results in a large amount of scrap with a corresponding reduction in yield for the calender line. Typically, the outer three to five inches at the edges of the fabric are unacceptable because of an over concentration of cords. This particular problem has troubled the tire and rubber industry for many years. To date, the industry has not developed an automatic spreading device that controls the count of the cords across the fabric preparatory to the fabric entering the calender.
Static devices, such as spread bars, have been added to the calender line immediately adjacent the entrant end of the calender. These bars have two to four indexed positions and they must be manually shifted as a different fabric is being processed. Such devices cannot control width, are not automatic and substantially increase labor costs and down time when changing fabric being processed in the calender line. The most common spreader immediately adjacent the calender is a three finger spreader. This device generally spreads to width; however, the cord count across the fabric is not controlled. Feedback arrangements for use on three finger spreaders are difficult to control and sometimes result in splitting of the fabric.
Bowed roll spreaders are commonly used to spread the fabric to the desired width. Indeed, four or five spreaders of this type may be used before the fabric enters the calender. The three finger spreaders are located six to eight feet beyond the last bowed roll spreader since a bowed roll spreader can not be located close to the calender. Consequently, the fabric necks down after the last bowed roll spreader and before it enters the calender itself For that reason, there is a need for a spreader to control fabric width immediately adjacent the entrant end of the calender. The three finger spreader is the device which is now commercially acceptable. Since a three finger spreader at this location can cause breakage of the picks and/or cords when using a feedback control, a fixed three finger spreader has been used to approximate the desired width of the fabric as it enters the calender. The only way to actually distribute the cord is the previously mentioned spreader bar that can be located immediately before the calender. This device is so labor intensive that it is not widely used. The operator must spread the fabric over the face of the bar before the line can be continuously operated. The calender lay down roll cannot be cleaned without removing the bar; therefore, the operator plays a substantial roll in a line which uses a spreader bar for distributing the cords prior to the calender. Thus, only width control devices have been used routinely in the tire industry for a calender line.
There has been, and still is, a substantial need for a device at the entrant end of the calender which can control the width of the incoming fabric while maintaining the desired cord count across the fabric and without damage to the fabric itself.
THE INVENTION
The present invention relates to a system for spreading the fabric before it enters the calender used in making rubberized tire laminating sheet material. In addition, the invention relates to a spreader for use immediately adjacent the entrant end of the calender and a grooved mandrel used in this novel spreader.
The fabric which is introduced into the calender has an upper and lower side, transversely spaced, parallel first and second edges and longitudinally extending tire reenforcing cords spaced laterally across the fabric between the edges. A system, according to the present invention, spreads this type of fabric preparatory to rubberizing the fabric in a calender as the fabric moves in a given path through a calender line to the calender so the edges of the fabric have a desired transverse location determining the desired width of the fabric entering the calender, while still maintaining an even distribution of cords across the fabric. The prior spreading devices were ineffective in correcting bunched cords at the edges of the fabric causing the edges to be scrap. The system of the present invention includes a pair of edge spreaders mounted on opposite sides of the fabric at the entrant end of the calender. Each of the edge spreaders includes a cantilever mandrel directed toward the center of the fabric, with an outer cylindrical surface concentric with a rotational axis. The mandrel is mounted so the outer surface of the rotating mandrel is generally tangential to a surface of the fabric, preferably the lower side of the fabric. The cylindrical outer surface of the rotatable mandrel includes a helical groove with convolutions having a pitch equal to the desired cord distribution
North American Manufacturing Company
Vanatta Amy B.
Vickers Daniels & Young
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