Open end spun slub yarn method and apparatus

#Open-end spinning of yarn is becoming increasingly commercially popular because of a number of inherent advantages of open-end spinning over conventional ring spinning. Some of the advantages of open-end spinning over ring spinning are: yarn formation and winding are not interdependent, allowing for removal of full packages while the machine is running; package size is theoretically unlimited; power consumption increases little with package weight; and package shape is suitable for most of the succeeding operations so that rewinding is eliminated. Additional advantages are the appearance, processability, and economy of the open-end yarns, and generally improved performance of end-products made with open-end yarns.

#While it is desirable to be able to produce open-end novelty yarns (particularly open-end slub yarns), there have been a large number of practical problems associated with conventional techniques and proposals for making open-end novelty yarns. As a result, most novelty (particularly slub) yarns now produced are ring spun. Present conventional and proposed methods for formation of slubbed open-end yarns include applying the slubs to the sliver before it is fed to the spinner; rapidly increasing or decreasing the feeding rate of the sliver; varying the withdrawal speed of the yarn from the spinner (U.S. Pat. No. 4,144,730); and forming the slubs exteriorly of the open-end spinning operation and then adding the slubs in a separate path to a point just before the yarn spinning device.

#All conventional and proposed techniques for making open-end novelty yarns have disadvantages associated therewith. For instance slubs added to the sliver require extra processing, they have a tendency to become lost as "trash" during the fiber separating stage (e.g. carding and combing), and they interfere with the combing of the fibers. Slubs made by controlling the feeding and withdrawal speeds of the sliver and yarn respectively do not allow production of a wide variety of different types of novelty yarn, and the slubs produced have a character that is undesirable for many operations. The feeding of slubs in a different path exterior of the open-ended spinning device requires the construction of an entirely separate system which can be expensive, takes up valuable room, and does not lend itself to ready adaptation to pre-existing equipment.

#FIG. 1 is a diagram illustrating the principle of open-end spinning, including a modification thereof to produce novelty yarns according to the present invention;

#FIG. 2 is a diagrammatic exploded view illustrating all of the component parts of an exemplary open-end spinning machine according to the present invention;

#FIG. 3 is a detailed sectional view illustrating fiber collection on a physical structure inserted in the fiber stream of the apparatus in FIG. 2;

#FIG. 1 shows an entirely diagrammatic representation of open-end spinning, illustrating the basic principles thereof. FIG. 1 indicates that in the first stage of the open-end spinning process the fibers are separated (from a source, such as a sliver) to provide a fiber supply. Next the individual separated fibers are transported as free fibers, primarily in a fiber transport section. The free fibers are then twisted to form the open-end yarn, and the yarn package is taken up. According to the present invention, the basic open-end spinning technique illustrated diagrammatically in FIG. 1 is modified so that novelty yarns in general, and slub yarns in particular, are produced. This is accomplished by forming effects from the free fibers during transport of the fibers from the separating to the twisting stages, and occasionally (preferably pseudo-randomly) allowing the effect fibers to pass to the twisting stage to be formed with the rest of the fibers flowing therewith into a slub yarn.

#An exemplary apparatus according to the present invention is illustrated schematically in FIG. 2. The structure illustrated therein comprises a conventional open-end spinning machine of the rotor type which has been modified to practice the present invention, the machine specifically illustrated being a modified SPIN-FLEX rotor spinning machine manufactured by Barber-Colman Company of Rockford, Ill.

#The apparatus of FIG. 2 includes a fiber separating device, illustrated generally at 12, and a fiber twisting device, illustrated generally at 14. A fiber transport section 15, defined by a conventional fiber transport tube 16 having a decreasing diameter conical cross-section, is disposed between the separating 12 and twisting 14 devices.