Textiles: weaving – Weft manipulation – Weaving with stationary weft supply
Reexamination Certificate
2000-05-30
2001-06-05
Falik, Andy (Department: 3741)
Textiles: weaving
Weft manipulation
Weaving with stationary weft supply
Reexamination Certificate
active
06240975
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a method and a device for limiting the weaving shed opening angle, especially in a loom that manufactures a fabric having at least one laid-in selvedge of a predetermined laid-in depth. The method and device relate to looms in which the free end of at least one bound-in weft thread in a front shed is guided back and tucked or laid into a subsequent front shed by means of at least one air jet. The weaving shed is formed by shedding mechanisms and consists of main or lower warp threads and face or upper warp threads, and would normally have a shed opening angle &agr; in the area of the fabric beat-up edge.
The free weft thread end that is guided into the subsequent shed is beat-up against the fabric beat-up edge together with at least one subsequent weft thread by means of a reed within the subsequent weft insertion period and is then bound-in to form the laid-in selvedge.
BACKGROUND INFORMATION
When manufacturing a length of fabric having at least one laid-in selvedge formed by means of a pneumatically actuated laying-in inserter or tucker, for example a laid-in selvedge on the weft thread insertion side, the weft threads are conventionally guided back into a subsequently opened front shed (weaving shed) by means of an airstream. It has been observed that these weft threads poke out through openings between adjacent selvedge warp threads of the upper and lower sheds respectively. In other words, the ends of the weft threads that are guided back into a shed do not remain in the intended position between the face and main warp threads so as to be properly bound in, but instead some thread ends stick out from the plane of the finished selvedge. As a result, the woven selvedge is not of high quality.
SUMMARY OF THE INVENTION
In view of the above, it is an object of the invention to provide a method of maintaining the end of a bound-in weft thread that is guided by means of at least one airstream back into an open weaving shed in the specified position between the main and face warp threads. It is a further object to provide a device for carrying out the method. The invention further aims to avoid or overcome the disadvantages of the prior art and to achieve additional advantages, as are apparent from the present specification.
The above objects have been achieved according to the invention by providing a method of limiting the front shed opening angle a that is formed between the upper and lower sheds by shedding mechanisms, to a limited shed opening angle &agr;
1
. The limited shed opening angle &agr;
1
is smaller than the normal shed opening angle &agr; and extends at least across the laid-in depth of the laid-in selvedge to be formed, viewed in the weaving or warp direction. The normal shed opening angle &agr; is defined as the angle between two lines, of which a first line extends from the beat-up edge to the point of maximum upper shedding deflection of the upper or face warp threads by the respective upper heddles or the like of the shedding mechanism, and of which a second line extends from the beat-up edge to the point of maximum lower shedding deflection of the lower or main warp threads by the respective lower heddles or the like of the shedding mechanism, in a given open loom shed. In other words, the normal shed opening angle &agr; is the angle between the upper and lower warp threads in an open shed if no special measures are taken to limit the opening angle of the warp threads.
By limiting the shed opening angle to a smaller angle &agr;
1
at least over the laid-in depth, the method according to the invention provides the advantage that an oscillating or fluttering motion of the free weft thread end is limited in the direction of the face and main warp threads. In this context, at least one airstream that guides the free end of the weft thread back into the weaving shed can act more directly upon the end of the weft thread when the front shed at the fabric edge does not open as wide as the conventional or normal front shed opening.
A shed opening limit device is provided according to the invention to implement the method according to the invention. The shed opening limit device comprises a support beam, a support beam extension, and a two-pronged or two-tined construction. The support beam extension is angled from the support beam and extends in the vertical direction of the weaving shed opening. The two-pronged construction is mounted on the support beam extension and has a first prong or tine and a second prong or tine that are arranged parallel to each other along their axes and spaced vertically apart from each other. The two prongs are fastened to the support beam extension outside and lateral to the front shed area. The first or upper prong and the second or lower prong each have a free end that extends across the front shed for a distance corresponding to the predetermined laid-in depth of the laid-in selvedge, at approximately a right angle to the direction of the warp of the front shed. The respective face and main warp threads of the front shed are guided between the two prongs of the limit device, which are spaced at an adequate distance from the reed and from the shedding mechanism respectively.
As the front shed opens, the warp threads of the upper and lower sheds at least near the edges of the weaving width are forced against the respective upper and lower prongs, whereby their further opening travel is stopped or limited. This effectively limits the conventional shed opening angle &agr; of the front shed formed directly by the shedding mechanisms to a limited shed opening angle &agr;
1
that is smaller than the conventional shed opening angle &agr;. Also, the limited shed opening angle &agr;
1
is defined by the vertical spacing between the two prongs of the limiting device and by the horizontal spacing between the prongs and the beat-up edge, which are adjustable.
The shed opening limit device is slidable within the front shed, that is, it is slidably adjustable between the shedding mechanism and the reed along X, Y and Z planes or axes. The two prongs themselves are adjustable at the support beam extension about their arrangement axis. In this way, the limited shed opening angle &agr;
1
of the respective selvedge warp threads of the upper and lower sheds can be optimally adjusted. To adjust the support beam along the X, Y, and Z axes, the free end of the support beam is releasably connected to a suitable fixed part of the loom by any known appropriate releasable fastening means.
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Birner Werner
Czura Peter
Hehle Josef
Reinhardt Herbert
Scorl Hans-Dieter
Falik Andy
Fasse W. F.
Fasse W. G.
Lindauer Dornier Gesellschaft mbH
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