Winding – tensioning – or guiding – Helical or random winding of material – Distributing material along the package
Reexamination Certificate
2001-09-17
2003-07-15
Mansen, Michael R. (Department: 3654)
Winding, tensioning, or guiding
Helical or random winding of material
Distributing material along the package
C242S481200, C242S483900, C310S017000, C310S019000, C310S020000, C318S127000
Reexamination Certificate
active
06592066
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a yarn guide for the traversing feeding of yarn to a rotatingly driven winding bobbin for producing a cheese in a winding head of a textile machine.
For the creation of textile bobbins it is necessary in principle to cause the bobbin to rotate, for one, and furthermore to traverse the yarn running up on the rotating bobbin along the bobbin axis. If the yarn is traversed very slowly, a bobbin with largely parallel windings is created. If such a bobbin is to have a larger volume and flat front faces, which are essentially arranged at right angles in respect to the bobbin axis, limiting flanges are required on both sides of the winding. These limiting flanges can be omitted if the yarn traverses so rapidly that crosswise winding results. High winding speeds then also demand a very high traversing rate.
Driving means oriented parallel in respect to the bobbin axis, for example belts, can be employed for this EP 0 311 827 A2 describes such a yarn guide, wherein the belt is driven by means of a step motor controlled by a microprocessor. By means of this it is possible to achieve high traversing speeds, and the yarn guide can be controlled relatively precisely.
A yarn guide, which is roughly assigned to the category of belt yarn guides, is also described in EP 0 453 622 B 1, which can generate the most diverse winding patterns by means of an appropriately controlled step motor, or also an electronically commutated disk-armature motor. Here, the motor is coupled to a driving wheel, around which a string, which carries a yarn guide support for the yarn guide, has been wound several times. A gear wheel is arranged on the same shaft, which meshes with two gear wheels arranged on both sides. In turn, these two gear wheels are fastened on torsion bars, each of which is prestressed in such a way that they are deflected in respect to their equilibrium position during the entire traversing interval of the yarn guide. It is intended by this to avoid load changes, which could lead to damage to the gear drive, particularly at high traversing speeds.
It is intended by the use of the torsion bars to make possible the large angular acceleration required in the area of the reversing points of the yarn guide. Couplings are provided for increasing this effect, which are intended to fix the torsion bars in place near the gear drive prior to the reversing points being reached, in order to achieve with this a shortening of the effective length of the torsion bars together with an abrupt change of the spring constant. For one, this construction makes great demands on the mechanical portions of the coupling, and the gear drive is furthermore not inconsiderably stressed. As a whole, the yarn guide, its yarn guide support, which is displaceable in a sliding rail, the string moving the yarn guide, reversing rollers for this string and the gear drive add to the inertia of the entire system, which has negative effects in particular at the reversing points of the traversed area.
So-called reversing thread rollers which, in connection with rapidly running bobbin winding machines, often effect the circumferential drive for the cheese simultaneously, are widely used for creating the traversing motion. However, here the same displacement angle always prevails, regardless of the fullness of the bobbin, wherein so-called winding patterns are created at defined number of revolution ratios between the bobbin and the drive roller, which lead to considerable problems in the course of subsequent unwinding. For this reason a multitude of so-called pattern disruption methods are described by the prior art.
For being able to create a predetermined winding pattern, for example a precision winding or a stepped precision winding, the drive of the bobbin must therefore be separated from the yarn guide. Inter alia, this is possible by arranging the already mentioned reversing thread roller at a distance from the winding bobbin and to drive it separately. As a rule, a yarn guide then slides in the reversing thread groove. Because of inertia, this system also suffers from disadvantages.
So-called finger yarn guides have been known for a long time (for example, DE-AS 11 31 575, DE-OS 15 60 360), wherein a yarn guide finger is pivotable around an axis which is arranged essentially vertically in respect to the winding bobbin axis. With this finger yarn guide, the transfer of the oscillating motion also takes place interlockingly by means of a cam disk, either directly to the finger yarn guide, as in DE-OS 15 60 360, or via a traversing rod, on which a double lever is resiliently suspended, which itself engages the finger-shaped yarn guide, as in DE-OS 11 31 575. The double lever additionally receives a pulse at the reversing points by means of an abutment, which favors the rapid reversal of direction at the edge of the traversing zone. However, in this case the abutment does not lead to considerable noise emissions or to a reduction of the service life of the device, since the invention is used for the creation of flanged bobbins, with which only a very narrow displacement angle is used. The advantage of both finger yarn guides is that the finger itself constitutes the yarn guide, without a sliding piece, which increases inertia, being additionally required here. Nevertheless, these yarn guides are also limited in respect to the flexibility of the yarn traverse.
Electromechanical drive mechanisms in place of the conventional mechanical drive mechanisms for the fingers used as yarn guides described here have been proposed in the meantime, such as indicated, for example, in EP 0 808 791 A2 or EP 0 838 442 A1, which defines the species.
The energy storage devices at the ends of the stroke of the yarn guide described and represented in EP 0 838 442 A1 are intended to assist the movement direction reversal of the yarn guide and therefore to relieve its drive mechanism, as well as to reduce the dwell time at the ends of the stroke. The position of the energy storage devices can be mechanically changed, so that the stroke of the yarn guide can be adjusted in order to avoid arched edges on the cheese, for example.
Because of the relatively jolting braking of the yarn guide when dipping into the respective energy storage device, such energy storage devices lead to a reduction in the service life of the traversing system, or require that it must have sufficient sturdiness so that its mass, and therefore mass inertia, is increased. At traversing frequencies of 30 Hz and more, however, the mass inertia already plays a considerable role in connection with the drive mechanism. Moreover, noise is created when the yarn guide impacts on the energy storage device, which adds up correspondingly because of the customarily long textile machines.
If the drive mechanism of the yarn guide is regulated by a control device, load bounces result in the area where the yarn guide dips into the energy storage device, which impair the regulating quality of the control.
SUMMARY OF THE INVENTION
It is therefore the object of the invention to improve the oscillation behavior of the yarn guide.
In accordance with the invention, this object is attained by means of a novel yarn guide for the traversing feeding of a yarn to a rotatingly driven winding bobbin for producing a cheese in a winding head of a textile machine. In accordance with the present invention, the yarn guide is directly connected with at least one mechanical energy storage device which is permanently coupled with the yarn guide during the entire traversing movement for aiding the reversal of the direction of movement. The potential energy of the mechanical energy storage device continuously increases in the direction toward the dead points of the traversed area. As a result, the mechanical energy storage device together with the yarn guide constitute an essentially harmoniously oscillating mechanical system.
The invention is advantageously further developed by the below-described additional features.
The direct connection of the yarn guide with a mechan
Flamm Franz-Josef
Hermanns Ferdinand-Josef
Sturm Christian
Kennedy Covington Lobdell & Hickman LLP
Mansen Michael R.
W. Schlafhorst AG & Co.
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