EP0770723A1

EP0770723A1 - Lace fabric and method of manufacturing the same

Info

Publication number: EP0770723A1
Application number: EP96113129A
Authority: EP
Inventors: Yasuhiko c/o Sakae Lace Co. Ltd. Motoya
Original assignee: Sakae Lace Co Ltd
Current assignee: Sakae Lace Co Ltd
Priority date: 1995-10-26
Filing date: 1996-08-16
Publication date: 1997-05-02
Also published as: JPH09119046A

Abstract

A lace fabric includes a plurality of wales (1) formed of warp yarns knitted in the form of loops. A plurality of elastic yarns (4) are knitted with each one of at least some of the plurality of wales (1), with each elastic yarn being knitted under a threading tension which ranges between about 1.0 and 2.5 times as strong as a threading tension of ground yarns including the warp yarns.

Description

BACKGROUND OF THE INVENTION

1. FILED OF THE INVENTION

The present invention relates to a lace fabric, typically a raschel fabric, which includes a number of wales of warp barns knitted in the form of loops and a method of manufacturing such lace fabric. More specifically, the invention relates to a lace fabric having wale-wise elasticity and a method of manufacturing the same.

2. DESCRIPTION OF THE RELATED ART

As known, a lace fabric is formed by knitting of yarns. There is also known a lace fabric of a type which is provided with positively increased wale-wise elasticity and expansibility by introduction of an elastic yarn such as a single rubber yarn or filament into some or all of wales forming the lace fabric, in addition to the slight elasticity inherent in lace fabrics in general per se.
Fig. 3 shows a raschel warp-knitting machine which is one example of lace knitting machines for use in knitting such lace fabric as above. Fig. 4 shows an exemplary lace fabric knitted by this machine and taken up about a fabric take-up roll of the machine. This raschel warp-knitting machine 20 includes a knitting head 24 for knitting the lace fabric 10, a take-up roll 25 for taking up the fabric 10 having been knitted by the knitting head 24, a ground-yarn beam 21 for threading ground yarns 11 such as a warp yarn 2, a weft yarn 5 and the like to the knitting head 24, an elastic-yarn beam 22 for threading an elastic yarn 4 to the knitting head 24 to be interlaced with the warp yarn 2, a pattern yarn beam 23 for threading a pattern-forming yarn 6a to the knitting head 24 to be introduced between the ground yarns 11 for forming an ornamental pattern in the knitted fabric 10 and other components. The knitting head 24, though not shown, includes a plurality of guide gars for guiding the ground yarns 11, elastic yarns 4, pattern-forming yarns 6a and the like, a plurality of knitting needles for chain-stitching the warp yarns 2, and a needle bar for vertically guiding the plurality of knitting needles. The lace fabric 10 is formed by this knitting head 24 and then taken up about the take-up roll 25. One vertical reciprocating movement of the knitting bars forms one course 7 of loops 3 of wales 1. Details of these operations will not be provided herein.
Fig. 4 shows an example of the lace fabric 10 taken up about the take-up roll 25. One simultaneous reciprocating movement of the plural needles chain-stitches loops 3 of a plurality of wales 1 at a time, with the weft yarn 5 being inserted between a loop portion 3a and a sinker portion 3b of some of the loops 3 so as to interlace the adjacent wales 1. These together form a ground portion 12. Further, in this ground portion 12 formed of the ground yarns 11, there are formed through holes or meshes 14. The mesh 14 will be formed differently, depending on a course pitch by which the weft yarn 5 is inserted. Conventionally, along each wale 1, a single elastic yarn 4 is inserted among the loop portion 3a, the sinker portion 3b and the weft yarn 5. And, the insertion or knitting of this the elastic yarn 4 is effected with maintaining the yarn 4 under an expanded condition, and the elasticity of this elastic yarn 4 provides the elasticity of the lace fabric 10.
Further, among the loop portion 3a, the weft yarn 5, the elastic yarn 4 and the sinker portion 3b, there is also inserted an inserting yarn 6 such as the pattern-forming yarn 6a, so that so that this inserted pattern-forming yarn 6a forms an ornamental pattern portion 13. The above-described ground yarns 11 and the inserting yarn 6 are all knitted together with the elastic yarn 4 under its expanded condition. That is, with release of the knitting tension, the fabric is contracted along the longitudinal direction of the wales 1 by the elasticity of the elastic yarn 4. Thus, theoretically, the fabric may be expanded to the maximum length assumed by this fabric during the knitting operation.
Conventionally, in order to increase the amount of contraction of the lace fabric 10 after the elastic expansion thereof, it has been necessary to increase the distance between the courses 7 on the machine. Then, for further increasing the contraction amount, the convention has suggested increasing the thickness of the elastic yarn 5 and increasing the threading tension to be applied to this elastic yarn 4 during the knitting operation. However, if such thick elastic yarn 4 is used and this yarn is knitted with the increased tension applied thereto, as shown in Fig. 3, each of the guide bars of the knitting head 24 on which the elastic yarns 4 are respectively engaged is subjected to an excessive load which urges this guide bar downwardly. And, this excessive load may be as large as or even exceed the permissive load of the guide gar of the lace knitting machine. Then, the excessive load will lead to deterioration of durability of the machine or such load will tend to over-restrict or interfere with the movement of the guide bar.
Taking the above-described state of the art into consideration, a primary object of the present invention is to solve the above-described problem of the prior art by providing an improved lace fabric and a manufacturing method thereof which makes it readily possible to increase the amount of elastic contraction without such inconvenience.

SUMMARY OF THE INVENTION

The above object is accomplished by the features of this invention set forth in the appended claims.
Namely, with a lace fabric according to the present invention, a plurality of elastic yarns are knitted with each one of at least some of the plurality of wales, with each elastic yarn being knitted under a threading tension which ranges between about 1.0 and 2.5 times as strong as a threading tension of the ground yarns.
With the above construction, a plurality of elastic yarns are knitted with the single wale. Then, the elastic yarns may be engaged on the plurality of respective guide bars without significantly increasing the threading tension to be applied by each guide bar to each elastic yarn. Thus, the threading tension of each guide bar may be not much different from that of the guide bar of a conventional machine. In other words, with the above-described fabric construction, a plurality of thin elastic yarns may be used in place of a single thick elastic yarn. So that, the threading tension of each thin elastic yarn may be maintained within a range of about 1.0 to 2.5 times as strong as the threading tension of the ground yarns. Accordingly, each elastic-yarn threading guide bar is not subjected to excessive load, and there occurs no disadvantageous effect on the durability of the machine.
As a result, the elastic contraction amount available from the lace fabric may be readily increased without deteriorating the durability of the knitting machine.
Preferably, the plurality of elastic yarns are knitted with each one of all of the wales. With this, it becomes possible to further increase the total elasticity available from the lace fabric.
Still preferably, at least two elastic yarns are knitted with each wale in such a manner that these elastic yarns cross each other within the wale.
In general, the elastic yarn has a greater frictional surface resistance than the ground yarns and other yarns to be inserted into the fabric. Then, if the two elastic yarns are knitted with the wale in the mutually crossing manner as described above, the frictional resistance between the crossing elastic yarns may be advantageously utilized for preventing these elastic yarns, when released from the threading tension, from resiliently retreating into the fabric from a length-wise cut edge of the lace fabric. Still preferably, at least some of the mutually crossing portions of the elastic yarns are heat-fused to each other by heat applied in the course of a fishing step of the lace fabric. This may restrict above-described resilient retreating dislocation of the elastic yarns more effectively.
According to a further aspect of the present invention, a plurality of elastic yarns are knitted with each one of at least some of the plurality of wales; and some of the elastic yarns are knitted across a plurality of wales at at least some of the courses of the fabric.
The lace fabric having the above construction advantageously obtains course-wise elasticity, i.e. the elasticity inter-wale direction, in addition to the wale-wise elasticity.
According to a further aspect of the present invention, there is provided a method of manufacturing a lace fabric comprising a plurality of wales including a plurality of loops of warp yarns, with a weft yarn being inserted between a loop portion and a sinker portion of some of the loops so as to interconnect the loops of adjacent wales, the method comprising the step of:

inserting a plurality of elastic yarns into each one of at least some of said plural wales by means of a plurality of guide bars to render the lace fabric into an elastic lace fabric;
wherein each said elastic yarn is inserted among said weft yarn, said loop portion and said sinker portion of the wale under a threading tension ranging between about 1.0 and 2.5 times as strong as a ground-yarn threading tension of ground yarns including said warp yarns and said weft yarns.

With the above features, a plurality of elastic yarns may be threaded by the plurality of respective guide bars without considerably changing the threading tension to be applied to each elastic yarn. Therefore, a lace fabric having stronger elasticity may be manufactured on the machine, without applying excessive load to guide bars of the machine. Moreover, it is not necessary to employ all elastic yarn having a significant thickness to achieve such strong elasticity.
As described above, the present invention has provided an improved lace fabric and a manufacturing method there for which may solve the problem of the prior art.
Further and other objects, features and effects of the invention will become more apparent from the following more detailed description of the embodiments of the invention with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is an explanatory view showing major portions of a yarn-knitted structure of a lace fabric relating to one preferred embodiment of the present invention,
Fig. 2 is an explanatory view showing major portions of a yarn-knitted structure of a lace fabric relating to a further embodiment of the present invention,
Fig. 3 is a side view of a conventional raschel knitting machine illustrating its lace knitting operation, and
Fig. 4 is an explanatory view showing major portions of a yarn-knitted structure of a lace fabric relating to the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described in particular with reference to the accompanying drawings.

[first embodiment]

Fig. 1 shows a lace fabric relating to the first embodiment. This lace fabric 10 does not differ from the conventional lace fabric with respect to a ground portion 12, an ornamental pattern portion 13 and a mesh 14. That is, warp yarns 2 form loops 3 and these loops 3 form a plurality of wales 1. Further, a weft yarn 5 is inserted between a loop portion 3a and a sinker portion 3b of some of the loops 3 so as to interconnect the adjacent wales 1. These warp yarns 2 and the weft yarns 5 knitted together form a ground portion 12. The ground portion 12 also defines a through hole or mesh 14. The shape of this mesh 14 will differ, depending on e.g. variation in the course pitch by which the weft yarn 5 is inserted. Further, among the loop portion 3a, elastic yarns 4 and the sinker portion 3b, an inserting yarn 6 such as a pattern-forming yarn 6a is inserted together with the weft yarn 5, so that an ornamental pattern portion 13 is formed by the inserted pattern-forming yarn 6a.
The elastic yarns 4, which comprise rubber yarns or filaments, are knitted along the wale 1 among the loop portion 3a, the sinker portion 3b, the weft yarn 5 and the inserting yarn 6. Each of the elastic yarns 4 is knitted under an expanded condition with a threading tension which is set to be about 1.0 to 2.5 times as strong as a threading tension of the ground yarn, i.e. the warp yarn 2 or the weft yarn 5. Further, the warp yarn 2, the weft yarn 5 and the pattern-forming yarn 6a are knitted together with the elastic yarns 4 while these elastic yarns 4 are maintained under the expanded condition. The elasticity of the elastic yarns 4 provides elasticity to the lace fabric 10.
The elastic yarns 4 include a first elastic yarn 4a and a second elastic yarn 4b. The first elastic yarn 4a is inserted between the loop portion 3a and the sinker portion 3b of each and every loop 3 of the wale. Whereas, the second elastic yarn 4b is inserted between the loop portion 3a and the sinker portion 3b of some of the loops 3 intermittently. Accordingly, the knitted fabric includes three types of loops 3; namely, one type in which the first and second elastic yarns 4a, 4b are inserted along one same direction, another type in which these yarns 4a, 4b are inserted in the mutually crossing directions, and the other type in which only the first elastic yarn 4a is inserted. For this reason, when heat is applied in the course of a lace finishing step, at those loops of the first and second types in which both of the first elastic yarn 4a and the second elastic yarn 4b are inserted, there occurs heat fusion between adjacent or crossing portions or of the first and second elastic yarns 4a, 4b, so that these fused portions become fixed in position in the longitudinal direction of the wale 1 of the ground portion 12. As a result, when this lace fabric is cut at a longitudinal end thereof, the elastic yarns 4a, 4b will not elastically recede into the lace fabric from the cut end. Moreover, as described hereinbefore, in some of the loops 3, only the first elastic yarn 4a is inserted. So that, at least these loops, with greater free space remaining therein, allow fairly loose insertion of the inserting yarns, so as to provide sufficient elasticity to the lace fabric. Incidentally, the elastic yarns 4 should be knitted with varying the pattern of insertion between the first elastic yarn 4a and the second elastic yarn 4b relative to each other. Therefore, these elastic yarns 4a, 4b are threaded by different guide bars. In this way, although the number of elastic yarns to be knitted is increased, the threading tension to be applied to each of the two elastic yarns may be maintained small so as to avoid applying excessive load to each guide bar.

[second embodiment]

Fig. 2 shows a lace fabric according to a second preferred embodiment of the present invention. This lace fabric 10 does not differ from that of the first embodiment with respect to the ground portion 12, the ornamental pattern portion 13 and the mesh 14. Namely, the warp yarns 2 form loops 3 and these loops 3 form a plurality of wales 1. Further, a weft yarn 5 is inserted between a loop portion 3a and a sinker portion 3b of some of the loops 3 so as to interconnect the adjacent wales 1. These interconnected warp yarns 2 and the weft yarns 5 together form the ground portion 12. The ground portion 12 also defines the through hole or mesh 14. The shape of this mesh 14 will differ, depending on e.g. variation in the course pitch by which the weft yarn 5 is inserted. Further, among the loop portion 3a, the elastic yarn 4 and the sinker portion 3b, an inserting yarn 6 such as a pattern-forming yarn 6a is inserted together with the weft yarn 5, so that an ornamental pattern portion 13 is formed by the inserted pattern-forming yarn 6a.
Like the first embodiment, elastic yarns 4, which comprise rubber yarns or filaments, are inserted under an expanded condition along the wale 1 among the loop portion 3a, the sinker portion 3b, the weft yarn 5 and the inserting yarn 6. The warp yarn 2, the weft yarn 5 and the pattern-forming yarn 6a are knitted together with the elastic yarns 4 while these elastic yarn 4 are maintained under the expanded condition. The elasticity of the elastic yarns 4 provides elasticity to the lace fabric 10.
Again like the first embodiment, the elastic yarns 4 include a first elastic yarn 4a and a second elastic yarn 4b. The first elastic yarn 4a is inserted between the loop portion 3a and the sinker portion 3b of each and every loop 3 of the wale. Whereas, the second elastic yarn 4b, in this embodiment, is inserted from one loop of one wale 1 to an adjacent loop of an adjacent wale 1 in one course 7 and then reversely from the loop of this adjacent wale to another loop of the original wale in a subsequent course 7. This running pattern of the second elastic yarn 4b is repeated with a skipping interval of two courses therebetween. And, in these two skipped courses 7, the second elastic yarn 4b is not inserted into the loops 3. In the adjacent wale 1 too, the first elastic yarn 4a is knitted and inserted between the loop portion 3a and the sinker portion 3b of each and every loop 3; and the second elastic yarn 4b is inserted in the same manner as above with the two-course skipping interval therebetween. With the above-described insertion patterns of the first and second elastic yarns 4a, 4b, at least the first elastic yarn 4a is inserted and knitted into the loops 3 along the longitudinal direction of the wale 1. Further, the second elastic yarn 4b too is inserted under the longitudinally expanded condition. As a result, the lace fabric 10 of this embodiment has the wale-wise elasticity, i.e. the elasticity in the longitudinal direction of the wales 1 like the fabric of the first embodiment. In addition, the fabric of this second embodiment also has the course-wise elasticity, i.e. in the width direction of the lace fabric 10. Incidentally, the first and second elastic yarns 4a, 4b are to be knitted in patterns differing from each other as described above. Thus, these elastic yarns 4a, 4b are threaded independently by different guide bars. Moreover, since the second elastic yarn 4b per se is to be knitted in the two different patterns, this second elastic yarn 4b is threaded by two guide bars. Although the construction of this embodiment requires an even greater number of guide bars, the construction has the same advantage as that provided by the construction of the first embodiment; namely, that the threading tension applied to each of the two kinds of elastic yarns 4a, 4b does not result in application of excessive load to the guide bar.
Other embodiments of the invention will be described next.

(1) In the foregoing first embodiment, the first elastic yarn 4a is inserted and knitted between the loop portion 3a and the sinker portion 3b of each of all of the loops 3, while the second elastic yarn 4b is inserted and knitted between the loop portion 3a and the sinker portion 3b of some of the loops 3 intermittently. Instead, both of these first and second elastic yarns 4a, 4b may be inserted and knitted intermittently into some of the loops, rather than all of them.
Incidentally, it is preferred that the first and second elastic yarns 4a, 4b cross each other at respective portions thereof inserted into the loop. Further, it is conceivable to insert both the first and second elastic yarns 4a, 4b into all of the loops. In this case too, it is preferred that the first and second elastic yarns cross each other at the respective portions thereof inserted into the loops.
(2) In the second embodiment, the first elastic yarn 4a is inserted into all of the loops of the wale, while the second elastic yarn 4b is inserted intermittently into some of the loops and across adjacent wales with a course skipping interval therebetween. Instead, it is also conceivable to insert the first elastic yarn 4a intermittently into some of the loops of one wale and insert the second elastic yarn 4b into the other loops of the wale skipped by the first elastic yarn 4a.
(3) In the second embodiment, the second elastic yarn 4b is inserted intermittently from one wale to another adjacent wale. Instead, the second elastic yarn 4b may be inserted from one wale to another wale apart therefrom across two or more wales therebetween.
(4) In the first and second embodiments described above, the two elastic yarns 4 are employed. In this invention, however, the number of the elastic yarns 4 is not limited to two, but may also be any number greater than two, such as three, four and so on.
(5) In the first and second embodiments, only the pattern-forming yarn 6a is inserted as the inserting yarn 6. Instead, any other inserting yarn 6 may be inserted so as to obtain a variety of the shape of the mesh 14. Conversely, the pattern-forming yarn 6a may be eliminated entirely. Further, in the first and second embodiments, the weft yarns 5 are inserted across the adjacent wales 1, 1 with a predetermined course-wise inter-distance therebetween. Instead, the weft yarns 5 may be inserted across the adjacent wales 1, 1 in each and every course 7 without such course-wise inter-distance. In these manners, the knitting patterns of these ground yarns 11 and the inserting yarn 6 are not particularly limited in the present invention.
(6) In the first and second embodiments, rubber yarns or filaments are employed as the elastic yarns 4. Any other elastic yarn or filament members may be used instead, as long as the members may be inserted into the wale to provide elasticity to the lace fabric.
(7) In the first and second embodiments as well as the above-described other embodiments, the elasticity of the elastic yarns 4 is used for providing elasticity to the lace fabric into which the elastic yarns 4 are knitted. Instead, the elasticity of the elastic yarns may also be utilized for a different purpose of floating up piles on the back side of the lace fabric. In this case, for instance, in addition to the construction shown in Fig. 1, a yarn having a good skin-feel, such as a cotton yarn, will be knitted along the wale into some of the loops thereof intermittently. Then, with the contraction of the elastic yarns knitted into the wale, the cotton yarn or the like will float up on one side, e.g. the back side of the knitted lace fabric.

The invention nay be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

A lace fabric including:
a plurality of wales (1) formed of warp yarns (2) knitted into the form of loops;
characterized in that
a plurality of elastic yarns (4) are knitted with each one of at least some of the plurality of wales (1), with each elastic yarn (4) being knitted under a threading tension which ranges between about 1.0 and 2.5 times as strong as a threading tension of ground yarns including said warp yarns (2).
A lace fabric as defined in claim 1,
characterized in that
the plurality of elastic yarns (4) are knitted with each one of all of the wales (1).
A lace fabric as defined in claim 1 or 2,
characterized in that
at least two elastic yarns (4) are knitted with each wale (1) in such a manner that these elastic yarns (4) cross each other within the wale (1).
A lace fabric as defined in any one of claims 1 through 3,
characterized in that
said elastic yarns (4) include a first elastic yarn (4a) and a second elastic yarn (4b); said first elastic yarn (4a) is inserted between a loop portion (3a) and a sinker portion (3b) of each and every said loop (3) of the wale (1), whereas, said second elastic yarn (4b) is inserted between the loop portion (3a) and the sinker portion (3b) of some of the loops (3) of the wale (1) intermittently.
A lace fabric as defined in claim 3,
characterized in that
at least some of the mutually crossing portions of the elastic yarns (4) are fused to each other.
A lace fabric as defined in claim 2,
characterized in that
said elastic yarns (4) include a first elastic yarn (4a) and a second elastic yarn (4b); said first elastic yarn (4a) and said second elastic yarns (4a), (4b) are inserted between a loop portion (3a) and a sinker portion (3b) of some of the loops (3) of the wale intermittently.
A lace fabric as defined in claim 1,
characterized in that
some of said plurality of elastic yarns (4) are knitted across a plurality of wales (1) in at least some courses (7) of the fabric.
A lace fabric as defined in claim 7,
characterized in that
said elastic yarns (4) include a first elastic yarn (4a) and a second elastic yarn (4b); said first elastic yarn (4a) is inserted between a loop portion (3a) and a sinker portion (3b) of each and every loop (3) of the wale (1), whereas, said second elastic yarn (4b) is knitted with a pattern in which said second elastic yarn (4b) is inserted from one loop (3) of one wale (1) to an adjacent loop (3) of an adjacent wale (1) in one course (7) and then reversely from the loop (3) of said adjacent wale (1) to another loop (3) of the original wale (1) in a subsequent course (7); and said pattern of the second elastic yarn (4b) is repeated with a skipping interval of two courses (7, 7) therebetween.
A method of manufacturing a lace fabric comprising a plurality of wales (1) including a plurality of loops (3) of warp yarns (2), with a weft yarn (5) being inserted between a loop portion (3a) and a sinker portion (3b) of some of the loops (3) so as to interconnect the loops (3) of adjacent wales (1),
characterized by the step of:
inserting a plurality of elastic yarns (4) into each one of at least some of said plural wales (1) by means of a plurality of guide bars to render the lace fabric into an elastic lace fabric;
wherein each said elastic yarn (4) is inserted among said weft yarn (5), said loop portion (3a) and said sinker portion (3b) of the wale (1) under a threading tension ranging between about 1.0 and 2.5 times as strong as a ground-yarn threading tension of ground yarns (11) including said warp yarns (2) and said weft yarns (5).
A method as defined in claim 9,
characterized in that
at least two elastic yarns (4) are knitted with each wale (1) in such a manner that these elastic yarns (4) cross each other within the wale (1).