Textiles: spinning – twisting – and twining – Apparatus and processes – Piecing up
Patent
1987-05-08
1988-11-01
Watkins, Donald
Textiles: spinning, twisting, and twining
Apparatus and processes
Piecing up
57301, D01H 1500, D01H 7885
Patent
active
047810173
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND AND SUMMARY OF THE INVENTION
The instant invention relates to a process for piecing to an open-end friction spinning device in which a yarn is back-fed into the nip, is connected therein with fibers and is then again drawn off continuously from said nip. The invention also relates to a device to carry out such process.
When a yarn breaks, or following a stoppage of the spinning process due to other causes, the feeding device is immediately stopped in order to prevent unnecessary fiber feeding which would clog and damage the spinning device. However, the opening roll continues to run as a rule, since stopping it separately for each spinning station would not only require a great technical effort, but starting and slowing down would take up a considerable amount of time. As a consequence, the fiber tuft which extends from the stopped feeding device into the range of the opening roll would be completely removed.
Based on the recognized fact that each stoppage of the feeding device causes a certain amount of damage of the fiber tuft, depending on the duration of the stoppage, proposals have been made in the past to divert the stream of fibers on its way to the fiber collecting surface and to guide it past the fiber collecting surface into a suction device. For this purpose, suction openings (see British patent publication 1,170,869 corresponding with U.S. Pat. No. 3,521,440) or compressed air openings (see German patent publication 3,104,444 corresponding with U.S. Pat. No. 4,384,451) have been provided in the feeding channel. Although undamaged fibers are fed precisely at the desired moment to the fiber collecting surface thanks to the uninterrupted fiber feeding and opening process, such openings within the highly sensitive fiber conveying path between the opening roll and the fiber collecting surface interfere with the spinning process. None of these proposals were therefore of practical significance.
It is the object of the instant invention to create a process and a device for piecing to an open-end friction spinning device which makes it possible to carry out faultless and secure piecing without affecting the subsequent spinning process.
This objective is achieved according to the invention in that the fibers are fed continuously to the nip but are then first taken out of the nip, in that the friction spinning elements are driven in spinning direction and in that the removal of the fibers is ended, in that the yarn end is back-fed to the forming accumulation of fibers and in that the yarn is drawn off from the nip while the fibers fed to said nip are continuously incorporated into the yarn. The removal of the fibers from the nip causes first of all those fibers which had been damaged through stoppage of the feeding device while the opening roll continues to run to be removed. Then, when the removal of the fibers from the nip during continuous feeding of fibers into the nip is ended, the undamaged fibers are deposited on the friction spinning elements and constitute a fiber accumulation there which is incorporated into the yarn end after said yarn end is back-fed, thus producing a piecing joint of great strength.
According to a preferred process, the fibers are brought through the nip onto the side of the friction spinning elements away from the nip, and are removed from there. In this way it is not necessary, for their removal, to greatly change the path of the fibers coming out of the fiber feeding channel. To remove the fibers it is advantageous if the spinning element normally rotating out of the nip is reversed in its rotation and is then again returned to its normal direction of rotation so that it again rotates out of the nip in order to terminate the removal of the fibers from the nip. Removal of the fibers if preferably effected by pneumatic, not by mechanical means.
Instead of going through the nip, the fibers can also be sucked away at a parallel to the nip, with a suction nozzle being used on the side of the friction spinning elements opposite to the draw-off side. The aspiration o
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Schubert & Salzer
Watkins Donald
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