Patent DE-10061337-A1 (DE)
Title: Open-end rotor spinning station has a yarn take-off tube for the yarn to travel on a straight path and then transfer into a diverging path to the take-off rollers with splicing rollers at the robot/spinner with yarn deflection
Inventor: BOCK ERICH
IPC: D01H4/40
Filed: 2000-12-08
Abstract: The yarn take-off tube, especially at an open-end rotor spinning station, leads the spun yarn (9) along an initial path (I) through the take-off tube (8) with little or no deflection. The yarn is transferred to a second path (II) at the outlet of the take-off tube, which takes it increasingly away from the line of the first path. The yarn take-off tube at an open-end spinner has a slit passage, with a decreasing length from the outlet to the inlet side. The passage has a circular cross section at the entry. The narrow side surfaces of the slit are rounded, and the long sides of the slit are parallel at least at the outlet. The yarn on the second path lies against the inner wall of the yarn take-off tube, at least at the outlet. The second yarn path is curved. The inner wall of the take-off tube is structured, at least along the second path, or it has a hard coating or an insert of a hard material at the outlet to form part of the tube inner surface. The coating or the insert are preferably of a ceramic material. The base body of the yarn take-off tube is of metal. The yarn take-off tube is extended by a take-off jet (7), which are bonded together or are in a one-piece structure. The cross section of the take-off tube can be restricted by a throttle at or near the tube outlet, using a swing plate. The mounting of the swing throttle section is vertically below the center of gravity with a horizontal offset. Or the throttle is a slide which is pushed into the take-off tube, with a spring to hold it in the open or closed position. The restricted passage, defined by the throttle, is a multiple of the spun yarn thickness and preferably three times the yarn cross section. The throttle can also be a groove or recess, to take the running yarn, and the throttle is laid at the yarn to reduce the passage cross section, using an elastic material for the throttle to apply a pliable pressure on the yarn. The throttle is of a wear-resistant material, where an opening is worn away by the running yarn. When the throttle is in place to close the yarn take-off tube, the second yarn path is free. The throttle assembly is fitted as a conversion kit, with a release clip or ratchet mounting at the yarn take-off tube. An Independent claim is included for an open-end spinning station with an operating unit to manipulate the throttle in the yarn-take-off tube. Preferred Features: The spinning station or a mobile robot (2) has a yarn transfer system (13,16) to carry the yarn from the first to the second path at the take-off tube. The yarn transfer has at least one pair of splicing rollers or a yarn deflection, where at least one of the splicing rollers (14,15) in the pair has a movement on a swing arm (17,18) at the spinning station. The yarn can be deflected by a guide roller. After the yarn has been transferred from the first to the second path, it is detached by a deflection roller or the splicing rollers and transferred to the yarn take-off rollers (10) at the spinning station. A further Independent claim is included for a yarn splicing operation where, at the start of the splicing action, the yarn travels along the first path as it is taken from the spinner, and then transferred to the second path, to be drawn along it at the nominal production speed. Preferred Features: The yarn is transferred to the second path when it has reached the nominal travel speed, and the transfer action starts when the spinner is accelerated from the splicing speed to the nominal speed. The timing of the yarn transfer from the first to the second path is dependent on the characteristics of the spinning machine and the characteristics of the yarn fibers, and especially according to the acceleration behavior of the yarn take-off and/or the shear strength of the spun yarn.