Textiles: spinning – twisting – and twining – Apparatus and processes – Splicing
Reexamination Certificate
1999-04-01
2001-01-09
Calvert, John J. (Department: 3741)
Textiles: spinning, twisting, and twining
Apparatus and processes
Splicing
C057S023000
Reexamination Certificate
active
06170247
ABSTRACT:
The present invention relates to a device for preparing the end of a thread to be spliced with an apparatus for the knotless pneumatic splicing of textile threads and yarns.
As is known, apparatus of this kind, commonly called “splicers”, comprise a small splicing chamber in which the knotless splicing of the ends of the two threads to be spliced takes place under the effect of a compressed fluid, normally air, introduced in the form of a jet through a nozzle.
These apparatus also usually provide devices for preparing or pre-treating the ends of the two threads to be spliced. In fact it is well known in the trade that to obtain a good join of the ends of the threads by splicing it is necessary to provide for accurate preparation by means of a pre-treatment of the ends of the said threads so as to eliminate the twist in them over a certain length and parallelize their fibers.
According to the prior art this pre-treatment takes place in various types of devices usually mounted on the pneumatic splicing apparatus.
For each thread to be spliced a known device of this type (U.S. Pat. No. 4,494,366) comprises a small tube which is mounted laterally with respect to the splicing chamber with its axis perpendicular to the plane in which the threads reach the splicing chamber and is passed through axially by a stream of pressurized fluid created by suction and/or intake of compressed fluid in a direction which is oblique with respect to the axis of the tube, into which tube the end of the thread to be pre-treated is inserted by means of the vacuum created at the inlet of the tube by the stream of pressurized fluid, to then undergo untwisting and parallelizing of the fibers on the part of the compressed fluid introduced in oblique direction. In this type of device problems may arise in inserting the thread end into the tube, particularly in the case of rigid or highly twisted yarns, as a result of insufficient vacuum at the tube inlet. A further problem which is encountered in the known device is that in order to obtain a good preparation of the ends, of the threads to be spliced it is necessary for the duration of treatment to be rather long, thus also prolonging the overall splicing time.
Other types of devices (German patent 3.804.648 or U.S. Pat. Nos. 4,829,759 and 4,890,451) have therefore been proposed, which still provide a small tube passed through axially by a stream of pressurized fluid and in which is inserted longitudinally a flexible plate locked at one end and free to oscillate at its other end under the effect of a pressurized fluid introduced in an oblique direction with respect to the axis of the tube.
In this case the end of the thread to be pre-treated and inserted into the tube is beaten by the vibrating free end of the flexible plate which facilitates and improves the untwisting and parallelizing of the fibers.
Although this device provides optimum pre-treatment results for all types of threads and yarns, including those which are highly resistant to untwisting, it has the disadvantage of comprising a moving component (the flexible plate) which is subject to fatigue and ageing phenomena over time and thus requires maintenance and replacement with some frequency.
Further known devices for pre-treating a thread end for knotless pneumatic splicing (German patent 38.28.319 or U.S. Pat. No. 5,175,983) still comprises a small tube intended to receive the thread end to be prepared, opposite which tube and axially at a distance in correspondence with one of its inlet ends for the end of the thread to be prepared is a nozzle for blowing a jet of pressurized fluid, while the internal surface of the small tube is rendered at least partially rough, so that the thread end introduced into the small tube is beaten against the said rough surface for a certain amount of time by the turbulent stream of fluid passing through the tube and thus undergoes the desired untwisting and parallelization of the fibers which make up the thread end. This type of device chiefly lends itself to the preparation of yarns with an irregular and non-traditional twist, of the open-end type of yarns and further comprises the risk of the fibers of the treated yarn being damaged by sharp edges on the rough surface of the small tube against which the end of the thread is repeatedly beaten. A device of this kind does not guarantee good pre-treatment results of yarns obtained by the traditional ring spinning methods and having a more or less strong S or Z intrinsic twist. In fact, to untwist such yarns, the stream of fluid acting on their end must be directed obliquely in the direction opposite to the intrinsic twist of the said yarn, otherwise, instead of causing them to untwist it would cause the intrinsic twist to increase. Therefore, for yarns with different twists, the direction of the stream of fluid used for untwisting should also be selected in a different manner from time to time.
The object of the present invention is to provide, for an apparatus for the knotless pneumatic splicing of textile threads or yarns, a device for preparing the thread end for splicing which-guarantees an optimum and reliable pre-treatment of the thread end in a reduced time so as not to impact excessively on the total time of the splicing operation, which may be used for all the various types of yarns to be treated, regardless of the direction of their intrinsic twist and of the fact that the twist is more or less strong, and which does not require any maintenance/replacement of component parts. Furthermore, the preparation device should permit a reliable capture of the thread end to be treated and rule out any risk of the thread reaching the pneumatic splicing operation without having undergone the necessary pre-treatment of its end or of the capture of the thread end requiring too long a time so as to reduce the time available for the preparation operation proper.
In view of this object, for an apparatus for the pneumatic splicing of textile threads and yarns having a small splicing chamber the invention proposes a device for preparing a thread end for splicing comprising a small treatment tube which is open at its opposite ends and suitable for receiving the end of the thread to be treated in correspondence with a peripheral point of its inlet end, and, at a distance from and opposite the said inlet end of the small tube, a circular nozzle for blowing a jet of pressurized fluid which is axially aligned with the said small tube and connected by means of a shut-off element to a source of pressurized fluid, characterized in that the end from which the jet of fluid emerges from the said nozzle is cut obliquely with respect to the axis of the nozzle so as to form an elliptical aperture, that the nozzle is mounted in rotatably adjustable manner about its own axis and that the nozzle's elliptical outlet aperture faces towards the peripheral point of the inlet end of the small tube in correspondence with which the latter receives the thread to be treated.
The invention is based on the observation that the jet of a pressurized fluid emerging from an aperture cut obliquely to the axis of a nozzle undergoes a diversion of its axis with respect to the axis of the nozzle so that when the diverted jet enters the small treatment tube axially aligned with the nozzle, the jet acts not centrally but in decentralized manner in the tube with the result that it causes the thread end inside the tube to untwist. If the nozzle is orientated about its own axis so that the major axis of its elliptical outlet aperture is in the plane passing through the axis of the tube and through the peripheral point of its inlet end in correspondence with which it receives the thread end to be treated, the nozzle is in a neutral position and the preparation device has no preference between treatment of yarns with an S-twist and yarns with a Z-twist. By rotating the nozzle by a certain angle about its own axis in one direction or the other it is possible to incline the major axis of the nozzle's elliptical outlet aperture with respect to the said plane
Ragnoli Fabrizio
Veronese Ruggero
Calvert John J.
Kramer Levin Naftalis & Frankel LLP
Mesdan S.p.A.
Welch Gary L.
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