Textiles: weaving – Warp manipulation – Traversing
Reexamination Certificate
1999-06-02
2001-05-08
Falik, Andy (Department: 3741)
Textiles: weaving
Warp manipulation
Traversing
C057S334000, C057S341000, C057S908000
Reexamination Certificate
active
06227253
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method and apparatus to twist at least two running threads about each other.
Methods and apparatus to twist at least two moving threads about each other are used on twisting devices to twist threads. Furthermore methods and apparatus to twist at least two moving threads are used in weaving machines to form a selvage weave, with at least two selvage threads being twisted around each other and filling threads being inserted between them. In this manner a selvage or a waste edge will be made.
2. Description of the Related Art
In a known weaving machine selvage forming device (U.S. Pat. No.
4,478,256),
reciprocating thread guides are used. A first kind of thread guide consisting of a needle with a thread eye is employed to guide a first selvage thread. Moreover, a second thread guide is employed, consisting of two elements fitted with diagonally opposite slits to guide a second selvage thread. The two thread guides are moved oppositely to each other in order to build a shed from the selvage threads. Also, the two elements of the second thread guide are simultaneously moved in mutually opposite directions with a slight gap between the elements to implement a lateral motion of the selvage thread that is guided through the slits. Such selvage forming devices employ reciprocating thread guides that cause excess noise and vibrations that arise from the additional wear in the drive device of the thread guides.
Another design for a selvage forming device (U.S. Pat. No. 3,880,199) provides a rotating disk with a pair of thread-guiding eyes that are situated diametrically opposite one another, with the axis of rotation positioned between the eyes and each eye guiding one selvage thread.
Another apparatus (French patent document A 2,095,367) uses a pair of eyes oppositely connected to an endless, driven belt, with each eye guiding one selvage thread, to form selvages or waste strips, with the belt driving the eyes substantially synchronously with the weaving machine's shed-forming device.
It is also known (as in British patent 819,583) to false-twist two or more threads and to wind them on a spool. As each of the threads is guided through an axial hole of a toothed wheel, the threads are twisted when the toothed wheel is driven in alternating directions of rotation.
SUMMARY OF THE INVENTION
The object of the invention is a method and apparatus to twist at least two running threads about one another without resorting to thread guide eyes or the like.
This problem is solved by making the threads move substantially transversely and at least approximately tangentially to a rotatable element and are guided in at least one guide passage of the rotating element. This guide passage forces the threads to reciprocate between two end positions in the axial direction of the rotating element and to mutually cross between these end positions.
Such apparatus is easily manufactured and requires only a single drive device. Furthermore, the threads moving along the guide passage migrate over a short distance of their lengths therein, and the wear on the apparatus, which is practically unavoidable, takes place not only at a single site, but instead, the wear is uniformly spread over the length of the guide passage(s). Accordingly, longer service life can be expected in comparison to an apparatus that guides each of the threads through a guide eye as disclosed in the prior art.
In a further development of the invention, at least one thread guide passage, during the thread crossing operation, guides threads at a radial distance from one other. This feature assures that the at least two threads when crossing will not hamper one other, and furthermore the threads will always cross in a predetermined direction.
The present invention solves the stated problem by providing a rotatable element having at least one endless guide passage that runs helically in an axial direction, with at least one crossing site and guiding at least two threads that are directed substantially transverse and approximately tangential to the rotatable element.
A similar rotatable element is known as a thread guiding drum according to the German patent document Al 4,237,860. The thread guiding drum is rotationally driven and which in turn, frictionally drives a bobbin. The thread guiding drum is configured with a thread guide channel to lay crosswise the individual thread moving onto the bobbin.
In an embodiment of the invention, the crossing segments of the guide channels are of differing radial depths, at least at the thread crossing. As a result, the threads will be crossed in a defined manner at the crossing site without hampering or running against each other.
In another embodiment of the invention, the guide passage comprises segments in the zone of the axial end positions and runs in the peripheral direction of the element such that the axial end positions can be reliably be kept constant over a period of time. This feature is especially advantageous when the apparatus is used to form selvages in a weaving machine because the shed formed by the selvage threads can be kept open longer to reliably permit the insertion of one or more fillings.
In a further embodiment of the invention, the rotatable element is mounted on the shaft of an electric drive motor. This design is especially preferred as a weaving machine's selvage forming device because of compactness and ease of assembly on the weaving machine. Moreover, the rotatable element can easily be rotated at constant speed.
In one embodiment, the rotatable element comprises a guide passage with a zone running 360° over the periphery of the cylinder surface from one axial end position to the other. In addition, a zone running at the oppositely directed slope also runs over 360° of the periphery of the cylinder surface between the two axial end positions, whereby the two zones form a crossing site approximately at the middle of the cylinder surface. In this embodiment the diameter of the cylindrical element may be comparatively small and as a result the apparatus may be kept compact and will be especially suitable as a weaving machine's selvage forming device.
In a further embodiment, the rotatable element comprises at least two endless guide passages running over a peripheral angle of 360° of the rotatable element, at least twice between the axial end positions and crossing each other at least twice per revolution of the rotating element. In this embodiment the threads can be looped twice about each other per each revolution of the rotatable element.
In yet another embodiment, at least two guide passages run between an end position in the zone of an axial end of the rotatable element and an end position in the zone of the axial middle position of this element, the crossing locations being provided in the zone of the middle end positions.
REFERENCES:
patent: 1216147 (1917-02-01), Lipps
patent: 4204394 (1980-05-01), Luthi
patent: 5456417 (1995-10-01), Kusters
patent: 5518039 (1996-05-01), Haeussler et al.
Bacon & Thomas PLLC
Falik Andy
Picanol N.V.
LandOfFree
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