BACKGROUND OF THE INVENTION
[0001] The present invention relates to a sewn product and a sewing method of material,
and particularly relates to a sewn product in which material edges having different
thickness, for example, an edge of a fastener tape and an edge of a main material
are stitched together and a sewing method for producing the same.
Related Art
[0002] For stitching a fastener tape for a slide fastener and a main material, in order
to ensure the strength of a stitched portion, the main material is overlapped on one
surface of the fastener tape at an edge-side of the tape in the width direction, and
then the fastener tape and the main material are stitched in plain seam. Subsequently,
the main material is folded back, and then, the fastener tape and the main material
are further stitched together. Generally, the main material is also overlapped on
the other surface of the fastener tape and then stitched with the tape in plain seem.
After that, the main material is folded back, and then the fastener tape and the main
material are further stitched together. Thus, the stitched portions are thick and
hard. In addition, since the main material and the fastener tape are partially overlapped
and then further folded back, both of the fastener tape and the main material are
necessary to have larger sizes for that. For example, the width of the fastener tape
is required to have five to six times of the width that is occupied by its elements.
Accordingly, both material costs for the fastener tape and the main material are high.
[0003] There is known a sewing method of material in which material edges are stitched together
without being superimposed, using a flat seamer sewing machine having four or five
needles and using six threads (e.g. refer to Patent document 1). According to the
sewing method using the flat seamer sewing machine, since the material edges are stitched
together in an abutted state, the unevenness in a stitched portion can be reduced.
In addition, since the material edges are stitched together with six threads, the
strength of the stitched portion can be ensured. However, in the sewing method of
material using the flat seamer sewing machine, the material edges are stitched together
with six threads, so that the thickness of the stitched portion is increased by thicknesses
of the threads, and the stitched portion is conspicuous due to its long width. Thus,
in a case where the edge of the fastener tape and the edge of the main material are
stitched together in an abutted state by using the flat seamer sewing machine, the
sewn width of the stitched portion is raised widely so as to cause a bumpy texture,
and the sewing holes appear complicated, which may be a damage for the design. Also,
when actually sewing them by using the flat seamer sewing machine, stopping force
against a lateral load is so weak that a gap is generated between the materials, and
thus, superimposed seam is mainly adopted for such stitching and materials-abutted
seam is rarely used.
[0004] Further, Japanese Patent No.
5,341,961 (Patent document 2) discloses a technique for solving the above-mentioned problems
in the sewing method using the flat seamer sewing machine. However, the Patent document
2 fails to disclose solving a specific technical problem which is caused when sewing
the materials with different thicknesses in materials-abutted seam. The inventors
of the present invention have found a problem that, in a case where an edge of a fastener
tape and an edge of a main material are stitched together in an abutted state by using
this technique, the fastener tape is finished waving in its longitudinal direction.
Moreover, it has been a conventional common knowledge that a fastener is sewn in the
superimposed (overlapped) seam as described above, and sewing in another method is
not suggested by the Patent document 2, nor such an idea is disclosed in any prior
art.
[Patent document 1] JP 2000-197783 A
[Patent document 2] Japanese Patent No. 5,341,961
SUMMARY OF THE INVENTION
[0005] Accordingly, the present invention has been made in view of the above problems, and
an object of the present invention is to provide a sewn product in which material
edges are stitched together and a sewing method for producing the same, in which a
thickness, a bumpy texture, hardness of a stitched portion of two materials with different
thicknesses, such as a fastener tape and a main material, would be reduced; the stitched
portion would be less noticeable and finished to be simpler; and the strength of the
stitched portion may be ensured.
[0006] Another object of the present invention is to provide a sewn product and a sewing
method of material, which would save material costs and simplify sewing processes.
[0007] Still another object of the present invention is to provide a sewing method of material,
which may reduce or prevent waving of a fastener tape.
[0008] In order to solve the above-described objects, according to one aspect of the present
invention, there is provided a sewn product in which an edge of a first material and
an edge of a second material that is thicker than the first material are stitched
together in an abutted state, wherein the edge of the first material and the edge
of the second material are stitched together with one bobbin thread and a plurality
of needle threads, the plurality of needle threads being interlocked with the one
bobbin thread to form a plurality of rows of zigzag stitched seams.
[0009] In the sewn product, two rows of zigzag stitched seams may be formed by two needle
threads, and wherein the edge of the first material may be overedge-stitched by one
of the two needle threads and the bobbin thread, and the edge of the second material
may be overedge-stitched by the other of the two needle threads and the bobbin thread.
[0010] In the sewn product, three rows of zigzag stitched seams may be formed by three needle
threads. One of the three needle threads may be stitched alternately to the edge of
the first material and the edge of the second material. The other two of the three
needle threads may be stitched to the edge of the first material or the edge of the
second material at both sides of the one needle thread.
[0011] In the sewn product, the first material may be a fastener tape to which elements
are attached.
[0012] In the sewn product, a length of the fastener tape in a width direction (see "T"
in FIG. 9) may be twice to four times of a length of the elements in the width direction
(see "E" in FIG. 9). In conventional stitching of a fastener tape and a main material,
since they are necessary to be partially superimposed or overlapped, a length of the
fastener tape in its width direction is required to be larger for that accordingly.
Thus, the length of the fastener tape in the width direction is required to be five
to six times of the width of the elements.
[0013] In addition, according to another aspect of the present invention, there is provided
a sewing method of material in which an edge of a first material and an edge of a
second material that is thicker than the first material are stitched together in an
abutted state, wherein the edge of the first material and the edge of the second material
are stitched together with one bobbin thread and a plurality of needle threads, the
plurality of the needle threads being interlocked with the one bobbin thread to form
a plurality of rows of zigzag stitched seams.
[0014] In the sewing method of material, the edge of the first material and the edge of
the second material may be stitched together with using a sewing machine which includes
a vertical full rotation shuttle and a plurality of sewing needles, wherein the plurality
of sewing needles are arranged in a direction perpendicular to a feed direction of
the first and second materials and sway in the direction perpendicular to the feed
direction.
[0015] In the sewing method of material, the first material and the second material may
be respectively fed with feed dogs that are set at different feed rates, while the
first and second materials are pressed at an equal pressure.
[0016] In the sewing method of material, the feed rate of the feed dog for feeding the
second material may be set to be higher than the feed rate of the feed dog for feeding
the first material.
[0017] In the sewing method of material, the first material may be a fastener tape to which
elements are attached.
[0018] In the sewing method of material, a length of the fastener tape in a width direction
may be twice to four times of a length of the elements in the width direction.
[0019] The present invention provides a sewn product in which material edges are stitched
together and a sewing method for producing the same, wherein a thickness, a bumpy
texture, hardness of a stitched portion of two materials with different thicknesses,
such as a fastener tape and a main material, would be reduced; the stitched portion
would be less noticeable and finished to be simpler; and the strength of the stitched
portion may be ensured. Further, the present invention provides a sewn product and
a sewing method of material, which would save material costs and simplify sewing processes.
Moreover, the present invention provides a sewing method of material, which may reduce
or prevent waving of a fastener tape.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020]
FIG. 1 is a top plan view showing one surface of a sewn product according to one embodiment;
FIG. 2 is a top plan view showing the other surface of the sewn product;
FIG. 3 is a three-dimensional view showing a sewing pattern at a stitched portion;
FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 1;
FIG. 5 is an elevation view showing one embodiment of a material sewing method;
FIG. 6 is a perspective view showing one embodiment of the material sewing method;
FIG. 7 is a front view that illustrates a state where a fastener tape and a main material
are fed with feed dogs while they are pressed by a material presser of a sewing machine,
in which the fastener tape and the main material are shown in cross-sections;
FIG. 8 is a perspective view that illustrates the feed dogs exposed above a throat
plate;
FIG. 9 is a cross-sectional view of a pair of left and right fastener tapes that are
stitched with a main material;
FIG. 10 is a top plan view showing one surface of a sewn product according to another
embodiment;
FIG. 11 is a top plan view showing the other surface of the sewn product;
FIG. 12 is a three-dimensional view showing a sewing pattern of a stitched portion;
and
FIG. 13 is a cross-sectional view taken along line 11-11 of FIG. 10.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Hereinafter, one embodiment of the present invention will be described with reference
to the accompanying drawings. FIG. 1 is a top plan view showing one surface of a sewn
product 10 according to one embodiment, and FIG. 2 is a top plan view showing the
other surface of the sewn product 10. As shown in the Figures, the sewn product 10
is produced by stitching an edge (hereinafter, also called as a "tape edge") 12A of
a fastener tape 12 as an example of a first material and an edge (hereinafter, also
called as a "material edge") 14A of a main material 14 as a second material that is
thicker than the fastener tape 12 in an abutted state without overlapping them. The
fastener tape 12 is a fabric or a knitted fabric. The main material 14 is a material
for producing clothes, a bag or the like, and examples thereof include felted fabric,
knitted fabric, compressed wool knit, jersey and the like, but the main material 14
is not limited to them. The sewn product 10 is clothes, a bag or the like which uses
a slide fastener (not illustrated).
[0022] In the present embodiment, the fastener tape 12 is thinner than the main material
14 (see FIG. 4, etc.), but the present invention is not limited to this embodiment,
and the main material 14 may be thinner than the fastener tape 12.
[0023] Two needle threads 16 and 18 and one bobbin thread 20 are used for stitching the
tape edge 12A and the material edge 14A. In the following description, the surface
of the sewn product 10, on which the needle threads 16 and 18 are exposed as stitched
seams is referred to as front, and the surface of the sewn product 10, on which the
bobbin thread 20 is exposed as stitched seams is referred to as rear. To the front
surface of the fastener tape 12, elements 15 (see FIG. 7, etc.) is attached.
[0024] The two needle threads 16 and 18 are arranged in parallel while positioning between
them a boundary line L where the tape edge 12A and the material edge 14A are abutted
to each other without being overlapped. The needle thread 16 forms zigzag stitched
seams on the front surface of the tape edge 12A, and the needle thread 18 forms zigzag
stitched seams on the front surface of the material edge 14A. The needle threads 16
and 18 are interlocked with the bobbin thread 20 at turning points 16A, 16B, 18A and
18B, thereby forming knots.
[0025] All of the turning points 16A of the needle threads 16 at the boundary line L-side
and the turning points 18A of the needle thread 18 at the boundary line L-side are
positioned on the boundary line L. The turning points 16A and 18B are arranged in
a direction perpendicular to the boundary line L (in X direction in the Figures) .
The turning points 16B and 18A are also arranged in the X direction. The intervals
L1 between the turning points 16A and 18B in the X direction and between the turning
points 16B and 18A in the X direction are set to a predetermined value (e.g. 2.00
mm). The interval L2 between the turning points 16A and 16B in the X direction and
the interval L3 between the turning points 18A and 18B in the X direction are set
to a predetermined value (e.g. 2.00 mm) . Accordingly, the width L4 of the stitched
seams formed by the needle threads 16 and 18 becomes a predetermined value (e.g. 4.00
mm)
[0026] As shown in FIG. 2, the bobbin thread 20 extends in the direction along the boundary
line L (Y direction in the Figures) while passing via the turning points 16A, 16B,
18A and 18B on the rear surfaces of the tape edge 12A and the material edge 14A. Here,
following the bobbin thread 20 in the Y direction, the bobbin thread 20 passes via
the individual turning points in the sequence of 18B → 18A → 16B → 18A → 18B → 16A
→ 18B (to be repeated).
[0027] FIG. 3 is a three-dimensional view showing a sewing pattern of a stitched portion
of the tape edge 12A and the material edge 14A. As shown in this Figure, following
the pattern of the bobbin thread 20 in the Y direction, the bobbin thread 20 forms
a knot together with the needle thread 18 at the turning point 18B and then forms
a knot together with the needle thread 16 at the next turning point 16A. Then, the
bobbin thread 20 passes via the same turning point 18B, forms a knot together with
the needle thread 18 at the turning point 18A and then forms a knot at the next turning
point 16B. Afterwards, the bobbin thread 20 passes via the same turning point 18A,
forms a knot together with the needle thread 18 at the turning point 18B and then
forms a knot at the next turning point 16A. This pattern is repeated.
[0028] FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 1. As shown in this
Figure, the tape edge 12A is overedge-stitched by the needle thread 16 and the bobbin
thread 20 between the turning points 16B-16A and the material edge 14A is overedge-stitched
by the needle thread 18 and the bobbin thread 20 between the turning points 18B-18A.
[0029] Here, since the tension of the needle thread 16 and the bobbin thread 20 that are
interlocked together to surround the tape edge 12A acts so as to compress the tape
edge 12A, the density of the tape edge 12A is increased. In addition, since the tension
of the needle thread 18 and the bobbin thread 20 that are interlocked together to
surround the material edge 14A acts so as to compress the material edge 14A, the density
of the material edge 14A is increased.
[0030] FIG. 5 is an elevation view showing one embodiment of a material sewing method, and
FIG. 6 is a perspective view showing the material sewing method according to this
embodiment. As shown in FIG. 5, a sewing machine to be used in stitching the tape
edge 12A and the material edge 14A together includes two sewing needles 1 and 2, a
vertical full rotation shuttle 4, and a throat plate 3, which is disposed between
the sewing needles 1 and 2 and the vertical full rotation shuttle 4. The two sewing
needles 1 and 2 are arranged parallel in the direction (the right and left direction
in the Figure) that is perpendicular to the material feed direction (from the front
side to the back side of the Figure). The sewing needles 1 and 2 are configured to
be moved upward and downward and to be swayed in the right and left direction of the
Figure by a swaying mechanism, which is not shown. The needle thread 16 is passed
through a thread hole of the sewing needle 1, and the needle thread 18 is passed through
a thread hole of the sewing needle 2.
[0031] The vertical full rotation shuttle 4 is a shuttle which rotates counterclockwise
in the Figure about a rotary shaft that is parallel to the material feed direction.
The shuttle 4 includes a bobbin (not shown) around which the bobbin thread 20 is wound,
and a sword tip (not shown) which widens loops of the needle threads 16 and 18, or
the like. The throat plate 3 is formed with holes through which the sewing needles
1 and 2 pass.
[0032] The sewing machine used for stitching the tape edge 12A and the material edge 14A
comprises: a material presser 30 (see FIG. 7) for pressing the fastener tape 12 and
the main material 14 that is thicker than the fastener tape 12 against the throat
plate 3 at an equal pressure; and a material feeding mechanism which includes feed
dogs 40a, 41a, 40b and 41b (see FIG. 8, etc.) for feeding the fastener tape 12 and
the main material 14 at different feed rates (or feed speeds). Processes for stitching
the tape edge 12A and the material edge 14A by using the sewing machine which has
the above-described structure will be explained as follows, but the material presser
30 and the material feeding mechanism which includes the feed dogs 40a, 41a, 40b and
41b will be described later. As shown in FIG. 6, the sewing needles 1 and 2 with the
needle threads 16 and 18 having passed through the thread holes thereof are caused
to penetrate through the turning points 16B and 18A, respectively, and the vertical
full rotation shuttle 4 is rotated while the sewing needles 1 and 2 are being pulled
upward. Here, the loops of the needle threads 16 and 18 are widened by the sword tip
of the vertical full rotation shuttle 4, the bobbin thread 20 is caused to pass through
the loops. In that state, the needle threads 16 and 18 are pulled upward. This causes
the needle thread 16 and the bobbin thread 20 to form a knot at the turning point
16B and the needle thread 18 and the bobbin thread 20 to form a knot at the turning
point 18A.
[0033] Afterwards, the fastener tape 12 and the main material 14 are fed in the Y direction,
and the sewing needles 1 and 2 are swayed rightward in the Figure so as to penetrate
through the turning points 16A and 18B, respectively. Then, the vertical full rotation
shuttle 4 is rotated while the sewing needles 1 and 2 are being pulled upward. This
causes the needle thread 16 and the bobbin thread 20 to form a knot at the turning
point 16A and the needle thread 18 and the bobbin thread 20 to form a knot at the
turning point 18B.
[0034] In subsequence, the fastener tape 12 and the main material 14 are fed in the Y direction,
and the sewing needles 1 and 2 are swayed leftward in the Figure so as to penetrate
through the turning points 16B and 18A, respectively. The vertical full rotation shuttle
4 is rotated while the sewing needles 1 and 2 are being pulled upward. This causes
the needle thread 16 and the bobbin thread 20 to form a knot at the turning point
16B and the needle thread 18 and the bobbin thread 20 to form a knot at the turning
point 18A. The above-described sequences are repeated, and thus the tape edge 12A
and the material edge 14A are sewn in a manner of two-row zigzag stitching while being
overedge-stitched by the needle threads 16 and 18 and the bobbin thread 20.
[0035] As described above, the stitched portion of the sewn product 10 produced by sewing
the tape edge 12A and the material edge 14A together via two-row zigzag stitching
with two needle threads 16 and 18 and one bobbin thread 20 has a sufficient amount
of tensile strength since the density of the tape edge 12A and the material edge 14A
is increased by the tension of two needle threads 16 and 18 and one bobbin thread
20.
[0036] Since the tape edge 12A and the material edge 14A are sewn with a small number of
threads, i.e. three threads, it is possible to reduce the thickness of the stitched
portion compared to that of the stitched portion with six threads using a flat seamer
sewing machine. This can reduce the unevenness of the stitched portion and a bumpy
texture or make the stitched portion less noticeable. In addition, since the width
of the stitched portion can be reduced compared to that of a stitched portion with
six threads using a flat seamer sewing machine, the former stitched portion can be
made much less noticeable. Here, when the sewn product 10 is a garment such as an
outerwear in which the stitched seams are exposed to the outside, it is possible to
improve the quality of design by making the stitched portions less noticeable.
[0037] In addition, in the sewn product 10 according to this embodiment, since the tape
edge 12A is overedge-stitched with the needle thread 16 and the bobbin thread 20 and
the material edge 14A is overedge-stitched with the needle thread 18 and the bobbin
thread 20, the tape edge 12A and the material edge 14A can be prevented from being
untied.
[0038] While stitching the tape edge 12A and the material edge 14A as described above, the
fastener tape 12 and the main material 14 are pressed onto the throat plate 3 at an
equal pressure by the material presser 30 (see FIG. 7). In addition, the feeding of
the fastener tape 12 and the main material 14 in the Y direction is set such that
the feed rate of the main material 14 which is placed in the right side will be slightly
higher than the feed rate of the fastener tape 12 which is placed in the left side,
by the left-hand feed dogs 40a and 41a and right-hand feed dogs 40b and 41b (see FIGs.
7 and 8) of the material feeding mechanism. The reason for such control is as follows.
Since the main material 14 is thicker than the fastener tape 12, if they are sewn
by using a usual sewing machine foot, the thinner fastener tape 12 could not be pressed
firmly by the sewing machine foot. If they are actually sewn in such a state, since
the sewing machine feeds the fastener tape 12 intermittently, the pressure to press
the material and tape would be changed, resulting in uneven feeding or pitch failure.
In order to prevent them, for applying an equal pressure to the fastener tape 12 and
the main material 14 respectively even if they have different thicknesses, the sewing
machine foot that has a seesaw function as the material presser 30 is used to press
the material and tape. However, the inventors of the present invention have found
that, when the fastener tape 12 and the main material 14 are sewn while they are pressed
at the same pressure, there are generated in the fastener tape 12 wrinkles that wave
in the longitudinal direction. Further, the inventors have found a cause that, when
the fastener tape 12 and the main material 14 are withdrawn underneath the material-press
parts that apply the equal pressure to them respectively, the main material 14 that
is thicker than the fastener tape 12 is stitched in a state of being slightly stretched
in the feed direction, and the stretched main material 14 is shrunk after being stitched,
thereby causing such wrinkles. In order to prevent this, the feed rate of the thicker
main material 14 under the equal press is set to be slightly higher than the feed
rate of the fastener tape 12.
[0039] FIG. 7 is a front explanatory view that illustrates a state where the fastener tape
12 and the main material 14 are pressed against the throat plate 3 at an equal pressure
by the material presser 30 of the sewing machine. In this Figure, the reference numerals
40a and 41a denote left feed dogs for feeding the fastener tape 12 in the feed direction
(the direction from front to rear of FIG. 7), and the reference numerals 40b and 41b
denote right feed dogs for feeding the main material 14. The fastener tape 12 has
elements 15 on its edge which is opposite, in the width direction, to the edge that
is to be stitched with the main material 14. The material presser 30 comprises: a
main body 31; and a pair of left and right material- press parts 32a and 32b that
are extended downward and frontward (toward the front of FIG. 7) from the main body
31. In this embodiment, the left material press part 32a presses the fastener tape
12, and the right material press part 32b presses the main material 14. The main body
31 incorporates an interlocking mechanism (a seesaw mechanism), which can equalize
both pressures of the material-press parts 32a and 32b for pressing materials with
different thicknesses, by accordingly lowering one of the material-press parts 32a
and 32b when the other is raised.
[0040] Such an interlocking mechanism is disclosed in, for example,
JP S56-17112 B. With such an interlocking mechanism, the fastener tape 12 and the main material
14 are pressed onto the throat plate 3 at an equal pressure by the material press
parts 32a and 32b, respectively.
[0041] FIG. 8 illustrates the left feed dogs 40a and 41a and the right feed dogs 40b and
41b that are exposed upward from openings of the throat plate 3 that is incorporated
in a table (not illustrated) of the sewing machine. These feed dogs 40a, 41a, 40b
and 41b are shown also in FIG. 7. The feed dogs 41a and 41b are divided into forth
and back portions in the feed direction with a needle hole between the forth and back
portions. In the present embodiment, the left feed dogs 40a and 41a are for feeding
the fastener tape 12, and the right feed dogs 40b and 41b are for feeding the main
material 14. Further, a feed rate of the right dogs 40b and 41b is set to be slightly
higher than that of the left feed dogs 40a and 41a. Such a technique that can set
each feed rate of the left and right feed dogs separately and independently is disclosed
in
JP H3-191984 A, for example.
[0042] As described above, by setting the feed rate of the thicker main material 14 to be
higher than that of the fastener tape 12 while pressing the fastener tape 12 and the
main material 14 at an equal pressure, the tape edge 12A and the material edge 14A
are stitched together without overstretching or overshrinking one of the fastener
tape 12 and the main material 14 compared to the other. Thereby, waving of the fastener
tape 12 in the longitudinal direction can be prevented. In addition, it is not necessary
to fold back the main material 14 at the time of stitching, and a facing is also unnecessary,
whereby material costs for the fastener tape 12 and the main material 14 may be saved,
and the sewing processes may be simplified.
[0043] FIG. 9 is a partial cross-sectional explanatory view that illustrates a pair of the
left and right fastener tapes 12 that are stitched with the main material 14. In the
present invention, the tape edge 12A and the material edge 14A are stitched together
in an abutted state without being overlapped. Thus, it is possible to shorten the
length of each of the fastener tapes 12 in the width direction compared to that of
a conventional fastener tape, and material costs may be saved for that. More in detail,
it has conventionally been necessary to set a total length (T) of the left and right
fastener tapes 12 in the width direction to be five to six times of a length (E),
in the width direction, occupied by the left and right elements 15 that are engaged
with each other, in consideration of margins to be overlapped with the main material
14. Whereas, in the present invention, it is possible to curtail the length (T) of
the left and right fastener tapes 12 in the element-closed state as small as twice
to four times of the length (E) of the left and right elements 15 in the width direction.
Usually, in a case of sewing fastener tapes in a state of overlapping with a main
material, when the length (E) of elements in the width direction ranges between 5
mm to 6 mm, the fastener tapes are mostly sewed while being pressed by a sewing machine
foot with a width of 4 mm. In this case, the length (T), in the width direction, of
the fastener tapes that are exposed after being sewn ranges from 13 mm to 14 mm, namely,
5 mm to 6 mm + 4 mm + 4 mm. This is one of the standard products that are familiar
to current consumers, and is a good-looking product that is demanded by consumers.
From this point of view for providing such a sewing product which is matched with
the consumers' needs, also in the present invention, the most preferable range of
the length (T), in the width direction, of the left and right fastener tapes 12 in
the element-closed state is 2.33 to 2.60 times (14/6 to 13/5) of the length (E) of
the left and right elements 15 in the width direction. In a practical sense, however,
the preferable range is twice to three times, if considering error spans of the processing
of the sewn products and their visual impressions. On the other hand, however, for
mass-producing such fasteners by existing automatic manufacturing equipment, the fastener
tapes are required to be held by being pinched by grippers of the automatic manufacturing
equipment for being conveyed between their respective production processes. Accordingly,
such fastener tapes are necessary to have a width which is enough to be held by the
grippers, whereby, from this technical limitation, it has found that the length (T)
of the left and right fastener tapes 12 in the element-closed state in the width direction
is required to be at least four times of the length (E) of the left and right elements
15 in the width direction. Therefore, in the case of mass-producing the fasteners
by the existing automatic manufacturing equipment while minimizing the exposed width
of the fasteners, four times is an upper limit.
[0044] FIG. 10 is a top plan view showing one surface of a sewn product 100 according to
another embodiment, and FIG. 11 is a top plan view showing the other surface of the
sewn product 100. As shown in these Figures, three needle threads 16, 18 and 22 and
one bobbin threads 20 are used for stitching the tape edge 12A and the material edge
14A. Also in this embodiment, the above-mentioned equal press of the fastener tape
12 and the main material 14 and an increase in the feed rate of the main material
14 are adopted.
[0045] The two needle threads 16 and 18 are arranged in parallel while positioning between
them the boundary line L at which the tape edge 12A and the material edge 14A are
abutted to each other. The needle thread 16 forms zigzag stitched seams on the front
surface of the tape edge 12A, and the needle thread 18 forms zigzag stitched seams
on the front surface of the material edge 14A. In addition, the needle thread 22 forms
zigzag stitched seams on the front surfaces of the tape edge 12A and of the material
edge 14A while bridging over the boundary line L. The needle threads 16, 18 and 22
are respectively interlocked with the bobbin thread 20 at the turning points 16A,
16B, 18A, 18B, 22A and 22B, thereby forming knots.
[0046] The turning points 22A and 22B of the needle threads 22 are positioned on the tape
edge 12A and the material edge 14A, respectively. The turning points 16A, 22B and
18B are arranged in the direction perpendicular to the boundary line (X direction
in the Figure), and the turning points 16B, 22A and 18A are arrange in the X direction.
[0047] As shown in FIG. 11, the bobbin thread 20 extends in the direction along the boundary
line L (Y direction in the Figure) on the rear surfaces of the tape edge 12A and the
material edge 14A while passing via the turning points 16A, 16B, 18A, 18B, 22A and
22B. Following the bobbin thread 20 in the Y direction, the bobbin thread 20 passes
via the individual turning points in the sequence of 18B → 18A → 22B → 16B → 22B →
18A → 18B → 22A → 16A → 22A → 18B (to be repeated).
[0048] FIG. 12 is a three-dimensional view showing a sewing pattern of a stitched portion
of the tape edge 12A and the material edge 14A. As shown in this Figure, following
the pattern of the bobbin thread 20 in the Y direction, the bobbin thread 20 forms
a knot together with the needle thread 18 at the turning point 18B, and forms a knot
together with the needle thread 22 at the next turning point 22B. The bobbin thread
20 forms a knot together with the needle thread 16 at the turning point 16A, passes
via the turning points 22B and 18B, and forms a knot together with the needle thread
18 at the turning point 18A. The bobbin thread 20 forms a knot together with the needle
thread 22 at the turning point 22A, and forms a knot together with the needle thread
16 at the turning point 16B. The bobbin thread 20 passes via the turning points 22A
and 18A and then forms a knot together with the needle thread 18 at the turning point
18B. This pattern is repeated.
[0049] FIG. 13 is a cross-sectional view taken along line 11-11 of bobbin thread 20 which
are interlocked together surround the tape edge 12A and the material edge 14A while
bridging over the boundary line L. At one side of the boundary line, the needle thread
16 and the bobbin thread 20 which are interlocked together surround the tape edge
12A. At the other side of the boundary line, the needle thread 18 and the bobbin thread
20 which are interlocked together surround the material edge 14A.
[0050] Here, the tension of the needle thread 22 and the bobbin thread 20 acts so as to
compress the portions of the tape edge 12A and the material edge 14A that are surrounded
by the needle thread 22 and the bobbin thread 20. This consequently increases the
density of the surrounded portions of the tape edge 12A and the material edge 14A.
In addition, the tension of the needle thread 16 and the bobbin thread 20 acts so
as to compress the portion of the tape edge 12A that is surrounded by the needle thread
16 and the bobbin thread 20. This consequently increases the density of the surrounded
portion of the tape edge 12A. Moreover, the tension of the needle thread 18 and the
bobbin thread 20 acts so as to compress the portion of the material edge 14A that
is surrounded by the needle thread 18 and the bobbin thread 20. This consequently
increases the density of the surrounded portion of the material edge 14A.
[0051] Since the density of the stitched portion of the sewn product 100 according to this
embodiment is increased by being compressed with three needle threads 16, 18 and 22
and one bobbin thread 20 at three positions, including the center and both sides in
the width direction, the tensile strength of the stitched portion can be increased
than that of the sewn product 10 according to the above-described embodiment. The
sewn product 100 may be made using three sewing needles in the similar method as in
the sewn product 10 as described above.
[0052] Although some embodiments of the present invention have been described, these embodiments
are provided only for better understanding of the invention but not intended to limit
the interpretation of the invention. The invention can be altered and improved without
departing from the purpose thereof, and includes equivalents thereof. For example,
in the above-described embodiment, the tape edge 12A of the fastener tape 12 and the
material edge 14A of the main material 14 that is thicker than the fastener tape 12
are stitched together, but the main material 14 may be thinner than the fastener tape
12. In this case, the feed rate of the fastener tape 12 is set to be slightly higher
than that of the main material 14 while they are pressed at an equal pressure. In
addition, in the sewn product 10 according to the above embodiment, although the turning
points 16A and 18A are disposed on the boundary line L of the tape edge 12A and the
material edge 14A, the turning points 16A and 18A may be disposed on the tape edge
12A or on the material edge 14A.
DESCRIPTION OF REFERENCE NUMBERS
[0053]
1, 2 sewing needle
3 throat plate
4 vertical full rotation shuttle
10 sewn product
12 fastener tape
12A tape edge
14 main material
14A material edge
15 element
16 needle thread
16A, 16B turning point
18 needle thread
18A, 18B turning point
20 bobbin thread
22 needle thread
22A, 22B turning point
30 material presser
32a, 32b material press part
40a, 41a, 40b, 41b feed dog
100 sewn product
1. A sewn product in which an edge of a first material and an edge of a second material
that is thicker than the first material are stitched together in an abutted state,
wherein the edge of the first material and the edge of the second material are stitched
together with one bobbin thread and a plurality of needle threads, the plurality of
needle threads being interlocked with the one bobbin thread to form a plurality of
rows of zigzag stitched seams.
2. The sewn product according to claim 1,
wherein two rows of the zigzag stitched seams are formed by two needle threads, and
wherein the edge of the first material is overedge-stitched by one of the two needle
threads and the bobbin thread, and the edge of the second material is overedge-stitched
by the other of the two needle threads and the bobbin thread.
3. The sewn product according to claim 1,
wherein three rows of the zigzag stitched seams are formed by three needle threads,
wherein one of the three needle threads is stitched alternately to the edge of the
first material and the edge of the second material, and wherein the other two of the
three needle threads are stitched to the edge of the first material or the edge of
the second material at both sides of the one needle thread.
4. The sewn product according to claim 1, wherein the first material is a fastener tape
to which elements are attached.
5. The sewn product according to claim 4, wherein a length of the fastener tape in a
width direction is twice to four times of a length of the elements in the width direction.
6. A sewing method of material in which an edge of a first material and an edge of a
second material that is thicker than the first material are stitched together in an
abutted state,
wherein the edge of the first material and the edge of the second material are stitched
together with one bobbin thread and a plurality of needle threads, the plurality of
the needle threads being interlocked with the one bobbin thread to form a plurality
of rows of zigzag stitched seams.
7. The sewing method of material according to claim 6, wherein the edge of the first
material and the edge of the second material are stitched together with using a sewing
machine which comprises a vertical full rotation shuttle and a plurality of sewing
needles, wherein the plurality of sewing needles are arranged in a direction perpendicular
to a feed direction of the first and second materials and sway in the direction perpendicular
to the feed direction.
8. The sewing method of material according to claim 6, wherein the first material and
the second material are respectively fed with feed dogs that are set at different
feed rates, while the first and second materials are pressed at an equal pressure.
9. The sewing method of material according to claim 8, wherein the feed rate of the feed
dog for feeding the second material is set to be higher than the feed rate of the
feed dog for feeding the first material.
10. The sewing method of material according to claim 6, wherein the first material is
a fastener tape to which elements are attached.
11. The sewing method of material according to claim 10, wherein a length of the fastener
tape in a width direction is twice to four times of a length of the elements in a
width direction.