Sewing – Elements – Thread cutting – severing or breaking
Reexamination Certificate
2001-03-20
2001-12-25
Izaguirre, Ismael (Department: 3765)
Sewing
Elements
Thread cutting, severing or breaking
C112S163000, C112S253000
Reexamination Certificate
active
06332419
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an auxiliary device of a sewing machine, capable of making three straight stitches and a net-like stitch and particularly to one which can help the net-like stitch securely formed on the cloth at the beginning of the sewing.
Referring to
FIGS. 7 and 8
and
9
, a conventional sewing machine capable of making three straight stitches and a net-like stitch on a cloth has a needle holder
5
, three needles
51
secured to the needle holder
5
, and a pressing member
57
provided to press the cloth. The sewing machine further has a lower shuttle needle (not shown) for a net thread to make a net-like stitch and three straight stitches (as shown in
FIG. 10
) together with the three upper needles
51
on the bottom of the cloth.
To make the above sewing machine capable of working more efficiently, a lower thread cutting device
55
(
FIG. 11
) is fitted under the flat-bed such that the threads
511
can be cut off automatically at the end of the sewing.
Moreover, referring to
FIG. 9
, a thread hooking device
54
is fitted to screw holes
512
of the sewing machine; the thread hooking device (
FIGS. 13 and 14
) was invented by the inventor of the present invention, and patented by R.O.C Intellectual Property Office with patent no. 286691 on Sep. 21, 1996. The hooking device
54
has a hooking plate
541
, and an elastic plate
542
which can clip the ends
510
of the threads cut off by the lower thread cutting device
55
for permitting the ends
510
of the threads to be covered by stitches of the next sewing.
However, the above sewing machine can't make net-like stitches on both the upper side and the lower side of a cloth as shown in FIG.
15
. To make two side net-like stitches, a shuttle
52
has to be fitted to the sewing machine, and the thread hooking device
54
removed, and a thread guide support
53
(
FIGS. 16 and 17
) is fitted to the screw holes
512
instead. The upper net thread
531
is passed through a curved hole
532
of the thread guide support
53
. Thus, the upper net thread
53
can be made into upper net-like stitches by means of the shuttle
52
. The sewing machine capable of making two-side net-like stitches is found to have a disadvantage that three of more lower side net-like stitches would fail to form at the beginning of sewing as shown in
FIGS. 17 and 18
because, referring to
FIG. 14
, when the threads
511
are cut off, the distance L between the right one of the needles
51
and the end
543
of the hooking plate
541
is relatively long as compared with the length (4~5 mm) of the ends of the threads
51
inserted into between the looking plate
541
and the elastic plate
542
. Consequently, the ends of the threads
51
would separate from the hooking device
54
easily at the beginning of sewing, resulting in the net-like stitches falling to form at the beginning.
Another conventional sewing machine capable of making three straight stitches and a net-like stitch on each side of a cloth has upper thread cutting device
56
besides the upper shuttle
52
and the thread guide support
53
; referring to
FIGS. 16 and 17
, the upper thread cutting device
56
cuts off the upper net thread
531
, and hold the end of the same automatically at the end of a sewing. However, the ends
510
of the threads
511
for the straight stitches are not held by any clipping device when the threads
511
are cut off by the lower thread cutting device
55
, so the operator of the sewing machine has to move the ends
510
rearwards with his hands such that the threads
511
are disposed between the pressing member
57
and the cloth. Otherwise, the upper net thread
531
would fail to form upper net-like stitch because the threads
511
are not disposed in a right position; when the threads
511
are disposed correctly, in the downward movement of the needles
51
, the upper net thread
531
, guided by the thread guide support
53
, will locate between the first thread
511
(the right one) and the right one of the needles
51
; thus, the upper net thread
531
can be made into net shape by the upper shuttle
52
and the thread guide support
53
, and secured to the cloth by the threads
511
as shown in FIG.
18
.
From the above description of the second conventional sewing machine, we can see that the sewing process is not efficient because the worker has to put the ends
510
of the threads
511
at the right position at the beginning of every sewing. Consequently, the cost is relatively high. Referring to
FIG. 19
, to overcome the above inconvenience, many clothes are fed to the sewing machine one after another such that the worker doesn't have to move the ends
510
of the threads
511
every time. However, the workers still have to cut off the threads between the clothes with a scissors afterwards, a waste of labor time.
From the above description, it can be understood that the conventional sewing machines have disadvantages as follows:
1. To make net-like stitches on two sides of a cloth, the sewing machine has to be equipped with the thread guide support, and the upper thread hooking device removed, i.e. the factories have to remove and install the auxiliary devices frequently for different orders placed by the customers. A small factory can't afford to hire a technician so the workers have to do the installation, resulting in problem of calibration. If the small factory sends for a technician for the installation, the cost is high, and it is a waste of time.
2. The workers have to spend much time in putting the ends
510
of the threads
511
in a right position for permitting a upper net-like stitch to be formed. And, referring to
FIG. 18
, relatively long end portions of the threads
511
would be left on the cloth.
SUMMARY OF THE INVENTION
Therefore, it is a main object of the present invention to provide an auxiliary device for a sewing machine capable of making a net-like stitch on each side of a cloth such that the upper net-like stitch can be securely formed on the cloth without the problems as described in the Background.
It is another object of the present invention to provide an auxiliary device for a sewing machine such that the factories don't have to frequently change parts for making two-side net-like stitches on a cloth, i.e. the auxiliary device is always fitted to the sewing machine and suitable for making both two-side net-like stitches and one-side stitch.
The auxiliary device of a sewing machine includes an upper clipping plate; the upper clipping plate is connected to a lower clipping member with a hooked plate movably inserted between a clipping end portion of the upper clipping plate and a clipping end portion of the lower clipping member.
The hooked plate can pull three first kind of threads into between the clipping end portions for same to be hold by the clipping end portions when the first threads are cut off from a cloth to be sewed with net-like stitch.
The clipping end portions are disposed relatively close to needles of the first threads, and under a curved hooked portion of a thread guide of a net thread provided for making the net-like thread such that the first threads won't fall off the clipping end portions when the needles of the first threads move down in sewing; the curved end portion of the thread guide is provided to support the net thread for same to be placed on the cloth with suitable shape by an upper shuttle.
The length of the ends of the first threads held between the clipping upper plate and the lower clipping member is about three to four centimeters, long enough to present the threads from falling off the clipping end portions to wrong position where a few units of the net-like stitches would fail to form.
To make only one-side net-like stitch, the net thread provided for making upper net-like stitch is removed from the upper shuttle and the thread guide, i.e. no parts have to be removed or installed in adjusting the sewing machine for different orders of products.
REFERENCES:
patent: 4550672 (1985-11-01), Kastrup
pa
Izaguirre Ismael
Rosenberg , Klein & Lee
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