Winding – tensioning – or guiding – Helical or random winding of material – Including wound package or empty spool handling
Reexamination Certificate
2000-04-24
2001-11-13
Mansen, Michael R. (Department: 3653)
Winding, tensioning, or guiding
Helical or random winding of material
Including wound package or empty spool handling
C242S475700, C242S481400, C242S486100
Reexamination Certificate
active
06315236
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for guiding and cutting a continuously advancing yarn, and winding initial layers thereof during a package doff in a takeup device, as well as to a method of guiding and cutting a continuously advancing yarn. An apparatus and method of this general type are known from EP 0 311 827.
In textile machines, for example, a crimped yarn is continuously wound to a package. After the package is completely wound, it is doffed. To this end, it is necessary that the yarn be first cut, so that the full package with the loose yarn end can be replaced with a new empty tube. During the doff, the yarn end of the continuously advancing yarn is received and removed by a pneumatic suction device. After completion of the package doff, the yarn is caught by means of a catching device and wound on the new tube.
In the apparatus and method disclosed in EP 0 311 827, the yarn is guided by a movable yarn guide outside of the winding range to a suction device laterally adjacent the winding range, after the package is fully wound. After completion of the package doff, and once the new tube is ready for catching, the yarn guide is pivoted back to the winding range. To transfer or catch the yarn, a transfer device deflects the yarn between the suction device and the yarn guide and offers it to the yarn catching device for engagement.
The known apparatus and method have the disadvantage that at the end of a winding cycle , the loose yarn end lies against the fully wound package in an undefined manner, which complicates locating the loose yarn end in particular in the further processing.
Furthermore, the deflection of the yarn by the transfer device for engaging the yarn leads to considerable looping, which results in major tension fluctuations in the yarn in proportion with the winding tension. Such tension fluctuations may lead to lapping on upstream feed elements.
It is accordingly an object of the invention to provide an apparatus and method of the initially described kind, so as to ensure that during a package doff, when the yarn is guided and caught, and when first layers thereof are wound, the yarn is guided as gently as possible with little deflection.
A further object of the invention is to ensure after cutting the yarn that the loose yarn end lies against a tie-off bead of the full package, and that the advancing yarn is threaded on a new tube without substantial slack.
SUMMARY OF THE INVENTION
The invention is characterized in that the yarn guide and the suction device are arranged within the winding range at the beginning of the package doff. In this connection, the winding range is the range on the tube, which is covered by the traversed yarn. Thus, the yarn can be cut with relatively little deflection and be taken over by the yarn suction device, so t hat no significant fluctuations occur in the yarn tension during the doffing phase. Preferably, the suction device is stationary. In the case of a suction device that is constructed for movement substantially parallel to the package, it is possible to place the loose yarn end with the tie-off bead in any desired position within the winding range.
To ensure that when the package is replaced with the empty tube, the yarn is reliably removed by the suction device, the drive roll or the tube includes a circumferential groove. Before the tube is brought into circumferential contact with the drive roll, the yarn is guided by the yarn guide, the yarn guide groove, and the suction device. This prevents the yarn advancing between the surfaces of the new tube and the drive roll from being clamped and braked by the new tube, as long as the latter has not yet reached its predetermined rotational speed. The yarn can then be transferred, without slacking, from the full package to a new tube. The suction device receiving the yarn ensures in the doffing phase an undisturbed yarn path in the devices upstream of the takeup device. The yarn guide groove may be formed radially extending in the circumferential direction on the circumference of the drive roll or on the circumference of the tube, so that during the acceleration of the tube the yarn is reliably guided without being clamped.
In a particularly advantageous further development of the apparatus, the yarn guide groove of the drive roll is formed in the circumferential portion of the drive roll or tube, which is contacted by the full package. This permits minimizing the deflections and deviations of the yarn during the doffing phase and, thus, the fluctuations of the yarn tension.
When the yarn guide groove is provided in the tube, it advantageously extends in the region of the tube, which is covered by the wound yarn.
In a particularly preferred development of the invention, the yarn guide groove is made with a groove depth T, which is at least greater than the yarn diameter. In this instance, the yarn guide groove has a groove width B, which is substantially greater than the groove depth. This yarn guide groove that is made relatively shallow with a great width ensures that the yarn does not leave the guide groove due to its natural dynamics. When the unwound tube is in contact with the drive roll, it is made sure that the yarn advances freely through the guide groove. Both the small groove depth and large groove width further effect that the yarn guide groove on the circumference of the drive roll or on the circumference of the tube does not significantly affect the buildup of the package during the winding cycle.
In another advantageous further development of the invention, the yarn guide groove is designed and constructed such that the groove depth T is greater than the groove width B. This narrow yarn guide groove permits holding the yarn safely in the yarn guide groove. In addition, the package buildup remains unaffected during the entire winding cycle. In order that the yarn enters the narrow groove, the traversing yarn guide may guide the yarn across the groove slowly at a reduced traversing speed.
In another, advantageous further development of the invention, a plurality of narrow grooves are arranged close to one another. The yarn need not be exactly positioned and yet enters one of the narrow grooves safely. Since the package buildup is defined by a cross wind, its formation is not disturbed even in the presence of a plurality of yarn guide grooves arranged side by side.
In a particularly advantageous further development of the apparatus, the cutting device, the yarn guide, the yarn guide groove on the circumference of the drive roll, and the suction device are arranged in a transfer plane. This permits depositing the yarn at first as a tie-off wind on the full package and transferring it to the suction device without substantial deflection. Furthermore, a simple swing motion of a transfer device enables the yarn to enter the cutting device of the suction system. In this instance, a deflection is needed only in the transfer plane. The gripping arm of the transfer device engages the yarn in its advance between the previously raised package and the yarn guide. This development has furthermore the advantage that when the package is raised from the drive roll, the transfer device keeps the yarn safely guided in the yarn guide. Preferably, the transfer plane is formed as a normal plane of the package and contains the tie-off wind of the package. In this normal plane, the yarn guide groove is provided on the drive roll. However, it is also possible to design and construct the yarn guide groove obliquely to the axis of the drive roll. This imparts to the yarn a wobbling motion, which leads to an improved cohesion of the yarn layers, when the tie-off wind is wound.
In the previously described operations for doffing the package, catching the yarn, and winding initial layers thereof, there exists the possibility that an auxiliary device removes the yarn from a traversing yarn guide at the beginning of the package doff, and that subsequently the yarn guide of the auxiliary device receives the yarn. In this instance, the yarn guide is c
Dammann Peter
Oberstrass Detlev
Pyra Michael
Alston & Bird LLP
Barmag AG
Mansen Michael R.
LandOfFree
Apparatus and method for guiding and cutting an advancing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for guiding and cutting an advancing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for guiding and cutting an advancing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2605350