A typical open end spinning machine, such as the AUTOCORO.RTM. rotor spinning machine available from Schlafhorst of Charlotte, N.C., includes a series of individual open end spinning positions on both sides of the elongate machine. At each position, sliver is drawn from a supply can and into a rotor spinning area. The spun yarn is engaged and moved by a rotating take-up shaft, through yarn tensioning components, and is wound by a drive roll to form a yarn package.
The spinning positions on each side of the open end spinning machine share several common operating components. Among the common components are a rotating take-up shaft and a reciprocating traverse bar. At each spinning position, the take-up shaft has an enlarged diameter area for engaging and moving yarn from the spinning area. The moving yarn is directed back and forth over the enlarged diameter area by a yarn guide eyelet mounted on a plate and moved in a reciprocal motion by the traverse bar.
When a yarn parts, such as downstream of the take-up shaft, it is likely to wrap around and form an entangled mass, that is, a yarn lap, on the enlarged portion of the take-up shaft in the time before the movement of the yarn is fully stopped by operation of a stop motion. Due to the loss in production time that would result if the common take-up shaft were stopped to remove a yarn lap at only a single position, the yarn lap is instead pulled to the side of the enlarged diameter portion of the take-up shaft by the machine operator while the shaft continues to rotate.
A number of such yarn laps on the take-up shaft may accumulate at each position before the open end spinning machine is shut down for other scheduled maintenance and all of the accumulated yarn laps may then be removed. Unfortunately, an accumulation of yarn laps may require that the open end spinning machine be operated at a reduced speed, thereby resulting in decreased production efficiency. In addition, the accumulated yarn laps present a potential fire hazard.
It is known that the tendency of the yarn to part may be reduced to thereby reduce the accumulation of yarn laps between scheduled maintenance activities. For example, the use of 100% cotton, rather than a blend, may reduce the likelihood of yarn breakage; however, it is the customer who ordinarily dictates the types of yarns to be produced. In addition, attempts have been made to more precisely control the tension of the moving yarn to thereby reduce the number of yarn partings. Alternatively, the speed of the open end spinning machine may also be reduced to reduce fluctuations in yarn tension which may cause yarn partings. Unfortunately, attempts to more precisely control tension have proven unsuccessful and fail to directly address the problem. In other words, controlling the yarn tension is not effective once a yarn parting has occurred. Reducing the speed of the spinning machine reduces production efficiency and is, thus, also undesirable.
The problem of preventing the accumulation of yarn laps on the take-up shaft of an open end spinning machine has not heretofore been adequately recognized or addressed to Applicant's knowledge. Moreover, any proposed solution for preventing yarn laps must desirably take into account that there is a substantial investment in open end spinning machines and, accordingly, a solution must be compatible with these existing machines. In addition, the area of an open end spinning machine adjacent the enlarged diameter area of the rotating take-up shaft provides only very limited clearances between existing fixed and moving components, such as yarn tensioning mechanisms.
USPTO Backgrounds
USPTO Backgrounds