Winding – tensioning – or guiding – Tension control or brake – Supply controlled
Reexamination Certificate
1999-07-06
2001-05-01
Walsh, Donald P. (Department: 3653)
Winding, tensioning, or guiding
Tension control or brake
Supply controlled
C242S419300, C242S14700M
Reexamination Certificate
active
06224009
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a device for modulated braking of a weft yarn for textile machines.
More specifically, the invention relates to a device of the type disclosed in the prior EPA No. 99103942.1 by same Applicant, which comprises a set of three fixed yarn guiding eyes, which determine a straight path of the weft yarn through the device, and at least one controlled braking element, which is adapted to engage the yarn in the spaces between said yarn guiding eyes in order to divert its straight path for braking.
In such conventional device, a movable electromagnetic yoke, subjected to the interacting actions of a constant magnetic field and of a current which circulates in an excitation coil, actuates a first oscillating lever with which the braking element proper is rigidly coupled. Said braking element is constituted by a second U-shaped oscillating lever which arranges itself so as to straddle the central yarn guiding eye and engages the yarn in the free portions that lie between the central eye and the end eyes.
The movable yoke is formed by a hollow cylindrical support on which the excitation coil is wound; the coil is immersed in the field of a permanent magnet which generates a flux which circulates in a cylindrical shroud of a material having high magnetic permeance.
Although this conventional device has a response which is generally adequate in terms of reaction to the extremely rapid variations in the mechanical tension of the yarn that occur in modern weaving processes, it is not entirely satisfactory from the constructive point of view, because of a certain mechanical fragility of the movable yoke, whose mass is intentionally very modest, and from the functional point of view, due to some uncertainty in the operation of the movable yoke, which sometimes, especially in the processing of higher-count yarns, can be subject to an electromotive force which is insufficient to produce an adequate response to the device in the above specified terms.
SUMMARY OF THE INVENTION
The aim of the present invention is to provide a modulated braking device improved so as to eliminate the above mentioned drawbacks.
Within the scope of this aim, a particular object of the present invention is to provide a device for modulated braking of a weft yarn for textile machines, comprising a set of three yarn guiding eyes, which form a straight path for the yarn, and an oscillating lever, which is connected to a U-shaped braking element which straddles a central eye of said eyes and engages the yarn in free portions that lie between said central eye and the end eyes of said eyes in order to divert its straight path for braking, characterized in that said oscillating lever is controlled by an electromagnetic actuation means which comprises at least one permanent magnet which is constituted by a cylindrical body having a N-S polar axis arranged radially, said body being associated with a stem which is articulated to said oscillating lever and can move in a linear fashion inside a cylindrical shroud with high magnetic permeance, on which at least one coil is wound, an excitation current flowing through said coil; the axis of said cylindrical shroud, which coincides with the axis of the movable stem, being perpendicular to the polar axis of said cylindrical permanent-magnet body.
Advantageously, according to the present invention, said cylindrical permanent-magnet body is made of one of the magnetic materials neodymium, samarium-cobalt and alloys thereof, and is connected on a support of nonmagnetic material, typically polymeric material, which is stably rigidly coupled to said movable stem.
According to a different embodiment of the present invention, a linear motion sensor is associated with the movable stem of the electromagnetic actuation means and is capable of providing a feedback signal which allows to control the current supplied to the excitation coil and accordingly control the speed and/or method of motion of said stem.
REFERENCES:
patent: 357374 (1887-02-01), Darling et al.
patent: 1619677 (1927-03-01), Pierce
patent: 2635854 (1953-04-01), Richards et al.
patent: 2861778 (1958-11-01), Spurlin
patent: 3300161 (1967-01-01), Hermanns
patent: 3448307 (1969-06-01), Duris
patent: 3549917 (1970-12-01), Espenschied et al.
patent: 3709332 (1973-01-01), Rosen
patent: 4909379 (1990-03-01), Albeck et al.
patent: 4927093 (1990-05-01), Weidmann
patent: 4928028 (1990-05-01), Leibovich
patent: 5077515 (1991-12-01), St. Arnauld
patent: 5155399 (1992-10-01), Zimmermann
patent: 5309050 (1994-05-01), Morinigo et al.
patent: 5520351 (1996-05-01), Prospero et al.
patent: 5738295 (1998-04-01), Flamm et al.
patent: 5833440 (1998-11-01), Berling
patent: 5857637 (1999-01-01), Straaten et al.
patent: 5871163 (1999-02-01), Bertoli et al.
patent: 6066998 (2000-05-01), Trumper et al.
patent: 4335089 (1994-04-01), None
patent: 0467059 (1992-01-01), None
patent: 0527510 (1993-02-01), None
patent: 0826806 (1998-03-01), None
patent: 942083 (1999-09-01), None
patent: 97 49630 (1997-12-01), None
Josif Albert
L.G.L. Electronics S.p.A.
Modiano Guido
O'Byrne Daniel
Walsh Donald P.
LandOfFree
Device for modulated braking of a weft yarn for textile... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for modulated braking of a weft yarn for textile..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for modulated braking of a weft yarn for textile... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2572402