Winding – tensioning – or guiding – Unidirectional winding and unwinding – Fixed number of windings on winding surface
Reexamination Certificate
2001-03-07
2003-05-27
Mansen, Michael R. (Department: 3654)
Winding, tensioning, or guiding
Unidirectional winding and unwinding
Fixed number of windings on winding surface
C066S13200T
Reexamination Certificate
active
06568620
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a yarn feeder which can be used particularly for positive furnishing of yarns to textile machines.
BACKGROUND OF THE INVENTION
The yarns to be furnished to individual yarn consuming stations of a textile machine can have quite different properties, depending on the material used, the twist, the yarn thickness, and other characteristics, and these properties also are found in the yarn feeder. For instance, cotton yarns, synthetic yarns, different processed or equipped yarns, such as smooth yarns, twisted yarns, kinky yarns, and so forth can behave differently. As a rule, yarn feeders should be capable of furnishing several or all of the yarns mentioned without difficulties.
Problems can arise here with yarns that shed dust, that have filaments protruding from the yarn, that carry a relatively large amount of sizing, or that in some other way leave behind or cause traces or deposits on parts of the yarn feeder. Deposits of fluff, which are located especially on the yarn feed wheel of a yarn feeder, can impair yarn travel and yarn feeding and in an extreme case can cause the yarn to tear.
From German Patent DE 35 01 944 C2, a yarn feeder is known that has a rotationally supported and driven yarn feed wheel, which is formed by a yarn storage drum provided with a plurality of conical regions. A first conical region with a cone angle of 150 forms the yarn inlet region. This is adjoined by a further yarn inlet region with a cone angle of 14, which is adjoined by a practically cylindrical yarn storage region.
The diameter of the yarn windings resting on the yarn inlet region decreases in the axial direction of the relatively long yarn inlet regions. The incoming yarn pushes the windings, already located in the inlet regions, in the axial direction, causing them to migrate toward the storage region, and the yarn tension in the individual windings can then vary. The yarn properties affect this process.
From German Patent DE 33 26 099 C2, a yarn feeder is also known which also has a rotatably supported and rotationally driven yarn feed wheel. The yarn feed wheel has a yarn inlet region, defined by two cones adjoining one another, and a yarn storage region adjoining it via a step that in one version is cylindrical or ribbed. The yarn feed wheel can be in a single part or in multiple parts. From the same patent, it is also known to provide the yarn inlet region and/or the yarn storage region with recesses, so as to bring about only a single uninterrupted support of the yarn in these regions. The storage drum in each version has a disk-like flange that extends in the radial direction on its lower end remote from the yarn inlet region and forms a step with the yarn inlet region.
A yarn feeder is also known from Published Taiwanese Patent Application, published under No. 165470, with a yarn feed wheel which has a conically tapering inlet region, an approximately cylindrical yarn storage region, and a yarn payout region, which is formed by a portion embodied on the order of a pulley. At the transition from the storage region to the pulley-like portion, there is a conical transitional region. In the yarn storage region, a flutelike groove extending around the circumference is provided, which divides the yarn storage region into individual contact faces separated from one another.
The yarn feed wheel has a relatively complicated shape.
From Taiwanese Utility Model published under No. 314077, a yarn feeder is known that has a rotationally symmetrical yarn feed wheel which is embodied in one piece and has a yarn inlet region, a yarn storage region, and a yarn payout region. The yarn inlet region with a convex curvature follows an annular cutout from a torus, while the yarn storage region is approximately cylindrical. Adjoining the yarn storage region, the diameter of the yarn feed wheel gradually increases, resulting in a conical region with a cone angle of a few degrees.
The incoming yarn presses the yarn windings located on the cylindrical yarn storage region axially away from the inlet region during operation of the yarn feeder, and the static friction of the entire package has to be overcome.
From German Utility Model DE 296 16 525 U1, a yarn feeder is known with a yarn feed wheel made up of multiple parts, in which the yarn inlet region, the yarn storage region and the yarn payout region are formed by axially extending ribs, whose outer profile defines the contour of the yarn feed wheel. The ribs are held at their ends on end disks.
The package advancement on the yarn feed wheel brought about by the incoming yarn is limited to the narrow ribs in the yarn inlet region. The ribbed yarn payout region can lead to turbulent yarn travel.
From European Patent Disclosure EP-A 0 568 762, a yarn feeder is known that has a yarn guide drum which has a conical upper and lower edge, and between them has a cylindrically embodied yarn storage region. Over a certain portion of its axial length, the cylindrical yarn storage region is provided with slots, which are covered by the yarn package. Between the slots, there are lands whose outer contour is located on the cylindrical surface that is defined by the cylindrical storage region.
The yarn wound as a package onto the storage region rests on the edges of the lands, which can be disadvantageous in the case of delicate yarns.
Regardless of wear, different yarns and packages behave differently. Differences exist particularly between smooth yarns and yarns with filaments, in which individual windings rest on filaments of adjacent windings and can firmly clamp them. It will be appreciated, however, that the usefulness of yarn feeders should not be limited to certain yarns.
SUMMARY OF THE INVENTION
With this as the point of departure, it is the object of the invention to create a yarn feeder whose operation properties are largely independent of the nature of the yarn. This object is attained by a yarn feeder having a yarn feed wheel with a special geometry that facilitates the feeding and payout of yarn onto and from the yarn feed wheel.
The yarn feed wheel of the yarn feeder may have a wearproof surface, which is applied to a carrier of lesser hardness, such as a metal body, or it may entirely comprise these substances. The yarn feed wheel is preferably in one piece, which makes economical manufacture possible. The yarn feed wheel is preferably embodied without through openings in its yarn inlet region, storage region and yarn payout region, so that it surrounds a closed interior. The storage region is preferably embodied as a substantially closed surface configuration, in which as needed relatively small openings spaced apart from the yarn bearing regions can also be provided. Fluff or other deposits are then unable to stick in the openings over which the yarn sweeps and impede yarn travel. The abrasion resistance prevents the development of scratches or bumps or other traces of wear, which over the long term could interfere with proper operation, and especially the even advancement of the package.
In the yarn feed wheel with a ceramic surface, it has also proved to be advantageous to embody the yarn inlet region and the yarn payout region as a closed surface, preferably with a circular cross section at every point. Conversely, the yarn storage region can have a cross section other than the circular form. For instance, the cross section can be defined polygonally, and either straight or indented edges may be provided between the individual, somewhat rounded corners of the polygon. The indented edges may be concave or intermittently concave and convex.
Such a design prevents the deposition of continuous rings of fluff or relatively large plugs of fluff in recesses, and the support of the yarn package remains concentrated on individual edge regions of the yarn segment. This facilitates the axial displacement of the package, so that the package can be displaced in controlled fashion even with different yarns or threads. Even if the bearing faces become worn somewhat, conditions are not fundamentally changed, and the
Lampprecht Alfred
Leins Eberhard
Schmodde Hermann
Leydig , Voit & Mayer, Ltd.
Mansen Michael R.
Memminger-IRO GmbH
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