JPS6377490A - Blind stitching method and sewing machine - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a blind stitch method and a sewing machine, and particularly to a blind stitch method and a sewing machine that take into consideration thread end treatment at the beginning and end of sewing. It is something.

(Prior Art) As is well known, a blind stitch is a type of overlock stitch used to sew folded parts such as the hem of pants, and is sewn using a blind stitch sewing machine.

In order to automate the sewing machine mentioned above, the applicant has already proposed Japanese Patent Application No. 185557/1983, as shown in FIG.

Figure 6 shows only the main parts of the sewing machine, and its outline is that a needle storage device 2 is provided in the main body of the sewing machine, the needle inside is installed using the needle installation device W13, and the thread is threaded. Pass the thread through the needle hole using the threading means 4, and then use the thread cutting means (sixth
In the figure, the solenoid 7 transmits the signal to the link 6.5, and finally the link 5 operates the thread cutting means around the fulcrum 8. ) to cut the thread, and each of the above operations is semi-automated.

Reference numeral 9 denotes a needle, which is attached to the needle swing arm 10 and reciprocates in a needle passage 13 provided in the needle base 12 from the bottom left side to the top right side like a pendulum of a clock.

Further, the looper 11 reciprocates on the presser foot holder 14 like a clock pendulum by the operation of the upper shaft (not shown), and the above-mentioned hand 9
Blind stitching is performed depending on the relationship between the looper 11 and the looper 11.

In addition, there is a thread cutting means on the inside of the lower part of the support member 15.
At the end of the link 5 described above, a head 17 of a press rod to be described later is attached.
It is configured to press.

FIG. 7 is a view of only the thread cutting means when FIG. 6 is viewed from the direction of the arrow. As mentioned above, inside the lower part of the support member 15,
A press rod 18 integrated with the head 17 is attached to be movable by a spring 19, and a blade portion 21 is provided at the tip of the press rod 18, which is rotatable relative to a linear blade portion 20. The blade portion 20 moves forward by the operation, and the rotatable blade portion 21 rotates in accordance with this forward movement, and the looper 11
The thread 22 in the supported state is cut by the thread 22.

That is, each blade moves forward and enters into the tip of the looper 11, and cuts the hooked thread 22 at this portion.

(Problems to be Solved by the Invention) In the above-described structure, when the thread is cut, thread remains at the sewing start part and the end part (2) as shown in FIG.

Therefore, in order to finish the thread to a predetermined length, that is, to the extent that it extends slightly above the cloth, the remaining thread must be trimmed again, which poses a problem of increasing the number of man-hours.

The above discussion has been made regarding sewn products, but there are also problems with threads remaining on sewing machine needles, as described below.

That is, the thread of a predetermined size remains in the needle hole and is inserted, and the next time the needle is sewn, it is moved to the needle rest 1 as explained in FIG.
The needle moves within the needle passage 13 provided in 2 from the bottom left side to the top right side. In this case, since a predetermined tensile force is applied to the thread by the thread tension plate (Fig. 6, 23), the needle is pulled into the needle path 13.
As the thread moves through the needle and creates a loop, the thread will come out of the needle hole, and when there is little left, the needle will come out of the fabric.
(11 stitches are formed), and in the process of this needle coming out of the fabric, the thread comes out.

Therefore, after the thread has been sewn several times in this state, the thread will come back and become ready for sewing, but the sewing machine has the drawback that sewing cannot be performed until then.

The present invention has been made to solve the above problems, and provides a blind stitching method and sewing machine that automatically leaves a predetermined length of thread at the beginning and end of sewing and eliminates the need for trimming. It is an object.

[Structure of the Invention] (Means for Solving the Problems) The first invention is an invention of a method, in which a thread pulling process is performed prior to the sewing process, and the thread pulling process is performed at the same time as the thread cutting process. The thread is cut when the needle is at the highest position.

The second invention is an apparatus invention, in which a thread pulling mechanism is provided on the link for operating the thread cutting means to pull the thread in accordance with the thread cutting operation, and a thread cutting timing detection mechanism is provided on the feed base. Therefore, the thread is cut when the needle is at the highest position.

(Function) In the first invention, first, the thread is pulled in advance in accordance with the thread cutting process, and the thread cutting timing is set at the top of the needle, so that the thread remains protruding at the end of sewing and at the beginning of sewing. The length can be adjusted to an appropriate amount.

In the second invention, since the link is provided with a thread pulling mechanism, the thread can be pulled at the same time as the thread is cut, and furthermore, the thread cutting timing detection mechanism is provided on the feed base.
You can see the timing.

(Example) Examples will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the blind stitching method and sewing machine according to the present invention.

In the blind stitching method according to the present invention, a thread retrieval step is performed prior to the sewing step, and this retrieval step is performed at the same time as the thread cutting step.
This is when the looper is in its most upright position (the needle is at its highest position).

In other words, by focusing on the fact that the state in which the looper is in its most upright position is the state in which it is easiest to cut the thread, when this state is detected and the thread is cut, and at the same time the thread is sewn to the required length in accordance with this operation, I try to ensure that there is enough length to protrude above the first seam.

In FIG. 1, the same parts as in FIG. 6 are designated by the same reference numerals.

In FIG. 1, the deaf is a thread pulling mechanism, and a link 6 is inserted between two upright plates 25.25, and a hole 26 is provided in each upright plate 25.25 and the link 6. After inserting the thread 22 through the needle, it is passed through the needle hole.

The entire thread pulling mechanism C is formed integrally with the base plate 27, and its mounting position can be adjusted using screws 28.

29 is a thread cutting timing detection mechanism, and an indicator piece 30
The best timing for cutting is when the tip 31 of the blade is positioned above the indicated position 32. This matter will be detailed later.

Next, the operation will be explained.

In FIG. 1, the parts newly added in the present invention, that is, the thread pulling mechanism U and the thread cutting timing mechanism, do not have any influence on the original processing of the blind stitch sewing machine itself. .

Therefore, the needle 9 fixed to the needle swing arm 10 reciprocates in the needle passage 13 provided in the needle base 12 from the bottom left side to the top right side like a pendulum of a clock according to the reciprocating movement of the needle swing shaft (not shown).

On the other hand, the looper 11 also reciprocates on the presser foot receiver 14 in a clock pendulum shape in response to the above-mentioned operation, and blind stitching is performed.

Note that the blind stitch itself will not be described in further detail since the structure and operation of the sewing machine are well known.

When sewing is continued in this state, the thread is pulled in sequence, as shown in FIG. The blind stitch is completed according to this movement.

Figure 2 is a top view of the thread pulling mechanism C, and shows the thread 2
State 2 is shown by a solid line.

FIG. 3 is a diagram for explaining the thread cutting timing, and this diagram is a schematic view seen from the direction of the arrow in FIG. 1. That is, FIG. 3 only shows the mutual positional relationship between the thread cutting means consisting of the blade portions 20 and 21, the needle 9 and the looper 11.

It is assumed that the sewing operation described above is performed in sequence and a predetermined final point is reached. In this case, paying attention to the needle 9, it is obvious that the needle 9 is performing a reciprocating motion according to the solid line arrow with the thread 22 passed through the needle hole 33.

That is, it is a reciprocating movement from the @ position to the @ position.

Note that when the needle is in the ◎ position, the looper 11 is in the ◎' position and in its most upright state (the tip of the looper is at approximately 90 degrees with the plane of the blade 20, 21 of the thread cutting means). situation)
From this state, as the needle 9 moves in the @ direction, the loopers 1, 1 once retreat and further move laterally in the @ direction along the arrow. During this lateral movement, the looper 11, which has been in a standing position until now, gradually lies down, scoops up the yarn at point 2, reaches point c', and becomes the most upright position.

When this ◎' point is detected and the solenoid 7 is energized, the link 5 presses the head 17 of the thread cutting means in response to the suction operation of the link 6, advances the blade part 20, 21, and moves the looper 1.
The thread 22 is cut within the tip of the first comb.

Note that when the solenoid 7 is energized, the link 6 moves in the direction of the link 5, as shown in FIG. As shown in Figure 2, a dotted line-shaped slack (excessive tangled thread) is formed.

This yarn slack will be explained next.

It has already been explained that the thread is cut at the looper @' position in FIG. This position is the position where blind stitching is completed, and the thread can be cut at a predetermined length from the end.

On the other hand, at this position, the needle is at its highest position, and since the thread is cut at this position, although the thread is inserted through the four holes, its length is the shortest.

Therefore, the next blind stitch will be started in this state, but when the sword starts moving in the @ direction from this state, the needle will become slack without applying any tension, and the needle will reach its maximum length. In this state, that is, when the needle advances to the end of the needle rest 12, a loop is formed using the extra thread.

By adjusting the length of this extra slack, it becomes possible to leave a predetermined length of thread at the beginning of blind stitching.

Note that the length of the slack can be adjusted by a screw 28 at the end of the thread pulling mechanism.

FIG. 4 is an explanatory diagram of the thread cutting timing detection mechanism.

The indicator piece 30 has a ] shape, and its end is fixed to the connecting portion between the feed base 34 and the feed 35.

That is, as is well known, the feed table 34 moves the feed 35 in the direction of the illustrated arrow in response to the rotation of the upper shaft 36 connected to a pulley (not shown). This operation is performed using the instruction piece 30.
While moving in a circular motion, it also moves up and down. In this case, it is clear from the appearance that the uppermost position of the needle is the lowermost position of the indicator piece 30, so the sewing machine operator must make sure that the tip 31 of the indicator piece 30 is the indicator as shown in FIG. Position 32 (
It is set in advance so that when the indicator piece 30 is at the lowest position, its tip 31 is aligned with the indicator position 32. ), if you energize the solenoid and cut the thread, it will be at the position where it is easiest to cut the thread, and at the same time the end of the thread after cutting will be at an appropriate length, and the position will be adjusted according to the cutting operation. As a result, a predetermined length of thread can be left at the beginning of the next sewing.

FIG. 5 is a diagram of the protruding state of the thread 22-1 at the beginning and end when sewn according to the present invention, showing that according to the present invention, it is possible to automatically create an appropriate size that is neither long nor short. There is.

In the above embodiment, it was explained that the yarn cutting timing is detected at the lowest position of the indicator piece. Of course, it can be visually observed by lighting a light bulb.

[Effects of the Invention] As explained above, according to the present invention, the thread is cut when the needle is at its highest point, and the thread is pulled in accordance with this cutting operation, so that it is possible to cut the thread at the sewing start and sewing end positions. To provide a blind stitching method and a sewing machine that can leave a thread of an appropriate length and improve the efficiency of sewing work.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the blind stitching method and sewing machine according to the present invention, FIG. 2 is an explanatory diagram of the thread retrieval mechanism, and FIG. 3 is a schematic diagram illustrating the thread cutting timing. Fig. 4 is a composition for detecting thread cutting timing, Fig. 5 is a diagram of the protruding state of the thread at the starting end and end in the case of the present invention, Fig. 6 is a schematic diagram of a blind stitch sewing machine using the proposed method; FIG. 7 is a diagram showing the state in which the thread is cut, and FIG. 8 is a diagram showing the state of the thread remaining at the start and end points when sewing with a conventional blind stitch sewing machine. 1... Sewing machine body 2... Needle storage device 3.
...Needle mounting device 4...Threading means 5.6...
・Link 7... Solenoid 8... Fulcrum
9... Needle 10... Needle swinging arm 11... Louver 12... Needle rest 13... Needle passage 14...
... Presser foot holder 15 ... Support material 16 ... Thread cutting means 17 ... Head 18 ... Pressing rod
19...Spring 20.21...Blade part
22.22-1... Thread 23... Thread tension disc
24... Thread pulling mechanism 25... Upright plate 26... Hole 27... Board
28...Screw 29...Thread cutting timing detection mechanism 30...Indicator piece 31 Tip 32...
・Indicated position 33...Needle hole 34...Feed base 35...Feed 36...Upper shaft

Claims (4)

[Claims] (1) In the blind stitching method, a thread picking process is performed prior to the sewing process, and the thread picking process is performed at the same time as the thread cutting process, and the thread cutting timing is set when the needle is at the highest position. A blind stitching method featuring: (2) In a blindstitch sewing machine having a structure in which the bias of a solenoid is transmitted to a thread cutting means via a link to cut the thread caught on the tip of a louver, a thread pulling mechanism is provided in the link to cut the thread. This blind stitch sewing machine is characterized in that the thread is pulled in time with the cutting operation, and a thread cutting timing detection mechanism is provided on the feed base, so that the thread cutting timing is determined when the needle is at the highest position. (3) When the indicator piece attached to the feed stand reaches the lowest position,
A blind stitch sewing machine according to claim 2, characterized in that the thread is cut at the timing. (4) A blind stitch sewing machine according to claim 2, characterized in that a lamp is lit at the lowest moving position of the feed table to determine the thread cutting timing.