Textiles: weaving – Special-type looms – Multiple-shed
Reexamination Certificate
1999-05-26
2001-02-13
Calvert, John J. (Department: 3741)
Textiles: weaving
Special-type looms
Multiple-shed
C139S037000, C139S055100
Reexamination Certificate
active
06186186
ABSTRACT:
This invention relates to a weaving machine for manufacturing a face-to-face pile fabric, comprising a weft insertion device provided in order according to a top and a bottom insertion path to insert a respective weft thread between warp threads, and shed-forming means working together with a lifting device, of which first shed-forming means are provided in order to bring warp threads above and between the insertion paths, second shed-forming means are provided in order to bring warp threads between and below the insertion paths, and third shed-forming means are provided in order to bring warp threads above, between and below the insertion paths.
This type of face-to-face weaving machine enables pile fabrics to be woven according to a method whereby it is necessary to have at least three different operating (series of) shed-forming means.
Hence with these weaving machines among others a method can be utilized whereby in successive insertion cycles according to a top and a bottom insertion path a respective weft thread is inserted between warp threads while the positions of the warp threads are determined by shed-forming means working together with a lifting device, whereby first backing warp threads are brought alternately above and between the insertion paths so that a top backing fabric is woven, whereby second backing warp threads are brought alternately between and below the insertion paths so that a bottom backing fabric is woven, whereby pile warp threads are brought alternately above and below the insertion paths so that they form pile or are brought alternately above and between or between and below the insertion paths so that they are inwoven in the top or the bottom backing fabric, and whereby the pile-forming pile warp threads are cut through between the two backing fabrics. In that manner two pile fabrics are obtained.
This invention also relates to such a method, and the pile fabric manufactured according to such a method.
The above described weaving machine and method are known and are among others provided for face-to-face weaving of pile fabrics with areas in which pile-forming pile warp threads form a design, figure or pattern, and with other areas in which no pile is formed, and in which a pattern or effect (hereinafter called backing-warp-thread effect) is then made visible by the course of the warp threads of the backing fabric (hereinafter called backing warp threads).
A particular field of application of this weaving machine and method consists of weaving jacquard velvet with the characteristics mentioned in the preceding paragraph and with so-called weft effects by inserting (e.g. by means of a weft selection device) different colored weft threads. These weft effects contribute to a significant degree toward the typical wealth of colors of these types of fabrics. Such velvet cloths with areas without pile (chiseled) in which backing-warp-thread effects and weft effects appear are called “Italian Style Jacquard Velvet”.
When weaving on a face-to-face weaving machine with double weft insertion according to the above described method the shed openings between the warp threads may not be too small in order not to hinder the weft insertion. On the other the hand the shed openings may not be too large either in order, through the greater liftings which the lifting device has to perform, not to restrict the weaving speed too much.
With a weaving machine with a weft insertion means movable according to a top and a bottom insertion path with the shed forming between the backing warp threads the following must also be taken into account: the backing warp threads are preferably brought to such a height between and below the insertion paths that they can guide the top, respectively the bottom, insertion means during its movement. If the shed opening is to great, this advantage is then lost.
For the pile warp threads the position between the insertion paths is lower than this position for the backing warp threads for the top backing fabric and higher than this position for the backing warp threads for the bottom backing fabric. From their position between the insertion paths the pile warp threads must therefore be brought upward over a greater height than the backing warp threads for the top backing fabric in order to extend above these insertion paths, and be brought downward over a greater height than the backing warp threads for the bottom backing fabric in order to extend below these insertion paths.
The ideal shed opening for the pile warp threads with this method is therefore larger than the ideal shed opening for the backing warp threads.
A first embodiment of the known weaving machine with the above described characteristics is a double-rapier weaving machine provided with three separate jacquard machines, namely a three-position open-shed jacquard machine for the pile warp threads, a first two-position open-shed jacquard machine for the backing warp threads of the top backing fabric, and a second two-position open-shed jacquard machine for the backing warp threads of the bottom backing fabric.
With the above described weaving machine the positions of the pile warp threads and the positions of the backing warp threads are determined by shed-forming means (e.g. tackle devices) of various jacquard machines. On each jacquard machine the level at which the shed is formed and the size of the shed opening can be separately adjusted, so that an ideal shed opening can be obtained both for the pile warp threads and for the backing warp threads. The adjustment of the shed opening occurs through an alteration in the lifting height of the knife devices of the jacquard machines.
A second embodiment is distinguished from the first because of the fact that only one two-position jacquard machine is provided for all backing warp threads. All shed-forming means of the two-position jacquard machine work together with the same knife device, so that the shed between the backing warp threads for the top backing fabric is the same size as the shed between the backing warp threads for the bottom backing fabric. The shed between the backing warp threads for the top backing fabric must be formed at a higher level than the shed between the backing warp threads for the bottom backing fabric. This difference in height is adjusted by a suitable levelling of the harness of the two-position jacquard machine. The shed-forming means which position the pile warp threads are however part of yet another jacquard machine. Hereon, by increasing the lifting height of the knife system, a larger shed opening can be set. An ideal shed opening can therefore be set both for the backing warp threads and for the pile warp threads.
The known weaving machines however have the disadvantage that on the jacquard machine for the pile warp threads and on the jacquard machine(s) for the backing warp threads a different lifting height of the knife system has to be set in order to obtain a different shed opening. Furthermore each jacquard machine requires a separate drive, so that three or two separate jacquard drives must therefore be provided. This makes the unit rather complex and expensive.
All shed-forming means of the known weaving machines have one and the same ratio between on the one hand the intermediate distance between two warp thread positions and on the other hand the lifting height applied by the lifting device. Were these shed-forming means provided in one and the same jacquard machine they would be driven by the same knife system and therefore work together with knives with one and the same lifting height. Because of this between the various positions for the pile warp threads and between the various positions for the backing warp threads the same intermediate distance would be obtained. The shed between the pile warp threads would therefore always be the same size as the shed between the warp threads.
Were a shed opening then set, which is ideal for the backing warp threads, and is therefore just large enough so that the backing warp threads would not obstruct the weft insertion, but is also neve
Debaes Johnny
Vanderjeugt Bram
Calvert John J.
Creighton Wray James
Muromoto Jr. Robert H.
N.V. Michel Van de Wiele
Narasimhan Meera P.
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