1. Field of the Invention
This invention relates to an apparatus in which a whirling air current is exerted on an untwisted short fiber bundle drafted by a draft device to twist it thereby producing spun yarns.
2. Related Art Statement
The present applicant has previously proposed a pneumatic type spinning apparatus for producing real twist spun yarns, which has been already filed separately (U.S. Pat. No. 5,159,806, etc.).
The aforesaid apparatus Is a spinning apparutus having a rotational or a non-rotational hollow spindle and a guide member which protrudes with an extreme end thereof directed at an inlet thereof, wherein a whirling air current is jetted toward the spindle inlet to twist a fiber bundle moved out of a draft device.
In the above-described conventional spinning apparatus, a proportion of waste discharged along with an air current with respect to a total amount of supplied fibers (a waste rate) is a few percent, which is uneconomical.
In the above-described conventional spinning apparatus, fibers fed out of the front rollers are sucked in an inlet portion of a spindle and are applied twists at an extreme end of a guide member since progation of twists toward the upper stream side is stomped at the extreme end of the guide member. So, in this spinning apparatus, splicing-off amount of short fibers from the transferring fiber bundle becomes large under the influence of the air current if the distance between the front rollers to the extreme end of the guide member is long. Accordingly, the produced yarn is really twisted but the distribution of length of fibers of the spun yarn tends to be deviated toward long fibers, and the spun yarn becomes quite different yarn from a ring spinning yarn. On the other hand, if the distance between the front rollers to the extreme end of the guide member is short (,for example, using the sliver of mean avarage of fiber length to be 25.2 mm and setting the distance between the nip point of front rollers to the extreme end of the guide member to be 16 mm), a bounded spun yarn shown in FIG. 6b which comprises parallel core fibers and winding fibers is produced. During the process in which the fiber bundle transfers toward the extreme end of the guide member, breakage of fibers occurs and the rate of splicing-off of short fibers is 1.5%.