JPH1085472A - Seam and its forming device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent skipping and maintain high sewing product quality. SOLUTION: A single thread ring stitch 1a formed by one needle thread 2a of two needle threads 2a, 2b and another needle thread 2b formed by two needle threads 2a, 2b. And the lock seam 1b is provided upstream of the binding portion 3 of the single thread ring seam 1a in the sewing direction.
b, the single thread ring stitch 1a is thread-tightened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seam and an apparatus for forming the seam, and more particularly to a new seam formed by two needle threads and an apparatus for forming the seam.

[0002]

2. Description of the Related Art Conventionally, in order to prevent a decrease in work efficiency due to replenishment of a bobbin thread stored in a bobbin, sewing operation can be performed for a long time using two needle threads without using a bobbin thread. Seams have been proposed.

For example, in Japanese Patent Publication No. 53-36376, as shown in FIG. 13, a single thread ring seam thread A and an upper seam thread B parallel to it are used. 13 are parallel to each other in the stitch forming direction (sewing direction) indicated by an arrow T in FIG. 13, and a loop of the upper stitch thread B is drawn on the back of the cloth such that the binding portion C of the single thread stitch thread A is drawn into the cloth. The stitched seam is described inside.

Japanese Patent Publication No. 53-45739 discloses a method for forming a seam described in Japanese Patent Publication No. 53-36376 by using one of the needles with two needles. Describes a method of forming a stitch, in which a thread loop is formed, a single thread loop stitch is formed by the other needle thread, and a crossover portion of the back of the seam of the stitch is passed through the thread loop of one needle thread.

Further, Japanese Patent Publication No. 53-45739 discloses a needle which supports a needle thread in each of two needle holes and moves up and down (two needle holes per needle have their axial directions orthogonal to each other). A needle thread catching device that forms a thread loop by timing one needle thread up and down and catching one thread at the back of the fabric; and a vertical thread movement and needle thread catching A single-threaded ring stitch forming device for forming a single-threaded ring seam by timing the other needle thread to form a single-threaded ring seam and passing a crossing portion on the back of the seam into the one-threaded yarn loop; A forming apparatus is described.

[0006]

However, in the above-described conventional seam using two needle threads and the forming apparatus therefor, the stitches are arranged on one needle so that their axial directions are orthogonal to each other. In order to form two needle holes and use the needles to form the above-described stitches, it is possible to perform a long-time sewing operation using two needle threads. Easy to twist around the needle, (2) 2 per needle
To support the needle thread, the penetration resistance when the needle passes through the cloth is large, and the through hole is large, so that the cloth resistance when forming the loop of the needle thread formed on the back of the cloth is reduced. (3) The loop between the thick thread and the thin thread becomes unstable when changing the thread count and combination of two needle threads. This is problematic in that high quality sewing products cannot be maintained.

Further, a needle having two needle holes whose axial directions are orthogonal to each other has a problem in that it has a different shape from a general needle, is expensive, and requires a long time to obtain.

Further, a special hook having a special shape for catching the needle thread is required, and there is a problem that a seam forming apparatus for forming a seam is expensive.

Therefore, a new seam using two needle threads capable of preventing stitch skipping and maintaining high sewing product quality, and an inexpensive seam forming apparatus capable of easily forming the new seam. Is desired.

[0010] The present invention has been made in view of the above points, and a new seam using two needle threads capable of preventing skipping and maintaining a high sewing product quality, and a new seam using the same. It is an object of the present invention to provide an inexpensive seam forming device capable of easily forming a seam.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, a seam feature of the present invention according to claim 1 is formed by one of two needle threads. And a lock stitch formed by the other one of the two needle threads, and the lock stitch is provided on the upstream side of the binding portion of the single thread ring stitch in the sewing direction. The point is that the single thread ring stitch is thread-tightened.

By employing such a configuration, skipping can be prevented.

The stitch forming apparatus according to the present invention described in claim 2 is characterized in that the stitch forming apparatus is arranged in parallel in the sewing direction at an interval and one of them forms a single thread ring stitch. And the other is capable of supplying a needle thread for forming a lock stitch. The two needles, each of which can reciprocate up and down, and the two needles are attached to each other. An upper shaft driving means for reciprocating the two needles in the vertical direction in conjunction with the upper shaft, and a needle bar formed on the back of the cloth in conjunction with the vertical movement of the two needles. A looper that can be captured by passing a loop of the needle thread of one needle located on the downstream side in the sewing direction through the loop of the needle thread of the other needle located on the upstream side in the sewing direction; and At least one stitch after the one stitch inside the loop of the captured needle thread of the one stitch And capable of holding the yarn spreader to the needle thread of the needle is located, is the looper and the thread spreader to a point having a lower shaft system drive means to be operated in conjunction with the vertical motion of the two needles.

By adopting such a configuration, the stitch according to the first aspect can be easily formed, and the respective loops of the two needle threads formed on the back of the cloth can be properly formed. Since it can be formed, skipping can be reliably prevented. In addition, common needles,
Since the seam can be formed using the looper and the thread saw, the needle can be easily obtained, and the structure can be simple and inexpensive.

[0015] The feature of the stitch forming apparatus of the present invention described in claim 3 is that in claim 2,
The point is that the needle points of the two needles are arranged stepwise.

By adopting such a configuration, the looper can easily form a loop forming a single thread ring seam formed by one needle thread in a loop formed by the other needle thread on the cloth back. It can be easily captured by passing through.

Further, the feature of the stitch forming apparatus of the present invention described in claim 4 is that, in claim 3,
The point is that the needle point and the needle hole of one of the needles located on the downstream side in the sewing direction are disposed above the needle point and the needle hole of the other needle located on the upstream side in the sewing direction.

By adopting such a configuration, the looper can easily form a loop forming a single thread ring seam formed by one needle thread in a loop formed by the other needle thread on the cloth back. It can be more easily captured by passing through.

The stitch forming apparatus according to the present invention described in claim 5 is characterized in that, in any one of claims 2 to 4, the distance between the two needles is variable. It is in the point which did.

By employing such a configuration, the binding portion of the single thread ring stitch formed by one needle thread and the lock stitch formed by the other needle thread fasten the single thread ring stitch. The distance from the position can be adjusted.

The stitch forming apparatus according to the present invention described in claim 6 is characterized in that, in claim 5,
The point is that the interval between the two needles is made variable by exchanging the staples.

By employing such a configuration, the binding portion of the single thread ring stitch formed by one needle thread and the lock stitch formed by the other needle thread tighten the single thread ring stitch. The distance from the position can be easily adjusted.

Further, the feature of the stitch forming apparatus of the present invention described in claim 7 is that in claim 5,
The present invention is characterized in that the upper shaft driving means and the lower shaft driving means are formed so as to be driven by one driving source.

By adopting such a configuration, the economic burden can be reduced and the cost can be reduced.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings.

First, an embodiment of a seam according to the present invention will be described with reference to FIG.

FIG. 1 is an explanatory view showing a seam according to the present invention.

As shown in FIG. 1, the seam 1 of the present embodiment is formed by two needle threads 2a and 2b.
One of the two needle threads 2a and 2b shown in white in FIG. 1 forms a known single thread ring seam 1a, and the other needle thread 2a shown in FIG. The needle thread 2b is the back surface of a cloth (not shown) on the upstream side (the right side in FIG. 1) in the sewing direction indicated by the arrow T in FIG. 1 at a distance Pb from the binding portion 3 of the single thread ring stitch 1a. A lock stitch 1b for threading the single thread ring stitch 1a on the back of the cloth is provided.
Further, the single thread ring seam 1a is a lock seam 1b on the back of the cloth.
Of the lock seam 1b
The position at which the single-threaded ring stitch 1a is thread-fastened on the back of the cloth is between the binding portions 3 forming the pitch of the single-threaded ring stitch 1a.

In other words, the seam 1 of the present embodiment forms the single thread ring seam 1a with one needle thread 2a and simultaneously forms the lock seam 1b with the other needle thread 2b. The upstream side of the binding portion 3 in the sewing direction indicated by the arrow T in FIG. 1 is tightened with the lock stitch 1b, whereby the single thread ring stitch 1a is reliably prevented from being frayed. I can do it.

The seam 1 of the present embodiment has two yarns each on the front and back of the cloth, and is a single thread ring seam 1a.
In addition to maintaining the elasticity of the single thread ring seam 1a, it is possible to prevent the weakness after suturing, which is a drawback of the single thread ring seam 1a, and to improve the sewing state by improving the skin contact.

Furthermore, since the seam 1 of the present embodiment is formed by using two needle threads 2a and 2b,
Since a and 2b can be supplied from a spool (not shown) having a large amount of thread, a long-time sewing operation can be efficiently performed.

Further, the seam 1 of the present embodiment is
Since the thread paths of the two needle threads 2a and 2b are divided,
Skipping is reliably prevented, and high sewing product quality can be maintained.

Next, an embodiment of a seam forming apparatus according to the present invention for forming a seam according to the present invention will be described with reference to FIGS.

FIGS. 2 to 4 show an embodiment of a seam forming apparatus according to the present invention. FIG. 2 is a front view showing a state where needles are attached, and FIG. 3 is a perspective view showing a configuration of a main part. FIG. 4 is a perspective view showing the vicinity of the looper support.

The seam forming device 4 of the present embodiment is used by being arranged on a known sewing machine (not shown), particularly an industrial sewing machine, and the mechanism of each part such as a cloth feed mechanism and a balance mechanism will be described. Omitted.

As shown in FIG. 2, the stitch forming apparatus 4 of the present embodiment has two needles 5a and 5b. The two needles 5a and 5b are vertically moved by a well-known upper shaft driving means (not shown) called a needle bar driving mechanism which is interlocked with an upper shaft which is rotationally driven by a sewing machine motor as a driving source. A needle bar 7 is attached to a needle bar 6 which is reciprocally movable with a predetermined stroke. A detailed description of the upper shaft drive means will be omitted. The two needles 5a and 5b are disposed in parallel so as to be substantially along the sewing direction indicated by the arrow T in FIG. One of the two needles 5a, 5b located on the downstream side in the sewing direction indicated by the arrow T in FIG.
Is for forming a single thread ring seam 1a, and the other needle 5b shown on the right side in FIG. 2 located on the upstream side in the sewing direction shown by the arrow T in FIG. 2 is for forming the lock seam 1b. belongs to. The needle tip and the needle hole 5aa of the one needle 5a forming the single thread ring seam 1a are disposed above the needle tip and the needle hole 5ba of the other needle 5b forming the lock seam 1b. Further, by replacing the needle pin 7, the needle interval NP, which is the interval between the one needle 5a and the other needle 5b, can be changed. The needle interval NP determines an interval Pb of the lock stitch 1b for fastening the single thread ring stitch 1a from the binding portion 3 of the single thread ring stitch 1a. Therefore, by changing the needle interval NP to be variable, the single thread ring stitch 1a of the lock stitch 1b for thread-tightening the single thread ring stitch 1a.
The distance Pb from the binding portion 3 can be adjusted. As the two needles 5a and 5b, commercially available products generally used are used.

Incidentally, as a specific configuration in which the needle interval NP is made variable by exchanging the needle pin 7, the two needles 5
a, a plurality of staples 7 having different needle intervals NP capable of mounting the needles NP are formed, and a desired needle interval NP is selected by exchanging the needle staples 7; 2 in the needle mounting groove with the desired needle interval NP
A configuration in which the needles 5a and 5b are fixed and a desired needle interval NP is selected can be exemplified.

Further, the seam forming device 4 of the present embodiment
Has a well-known looper 8 and a thread saw 9 disposed below the needles 5a and 5b, as shown in FIG. The looper 8 and the thread saw 9 are rotatably supported inside a bed of a sewing machine (not shown), and are driven by a lower shaft system driven by a lower shaft 10 which rotates at twice the speed in conjunction with an upper shaft (not shown). By means 11, the two needles 5a,
5b can be interlocked with the vertical reciprocation.

That is, the lower shaft driving means 11 of this embodiment uses a single sewing machine motor (not shown) for driving the upper shaft driving means as a driving source.

The lower shaft drive means 11 is a lower shaft 1 output from a spur gear-shaped output gear 12 attached to the lower shaft 10.
The output rotation of 0 is transmitted to the looper 8 to drive the looper 8 to obtain a substantially trapezoidal movement locus, and the output rotation of the lower shaft 10 output from the output gear 12 is swung. And a thread rotation drive means 14 for converting the motion into a dynamic motion and transmitting the converted motion to the thread rotation 9.

The looper system driving means 13 has a spur gear-shaped driven gear 15 for a looper which is disposed diagonally below and to the right of the output gear 12 in FIG. 3 and always meshes with the output gear 12 at a rotation ratio of 1: 1. ing. The looper driven gear 15 is attached to the left end of the looper swing shaft 16 rotatably supported inside the bed (not shown), as shown in FIG. A looper rocking body 17 formed in a substantially cylindrical shape is attached to the right end shown in FIG. An eccentric pin 18 protrudes from the right end face of the looper rocking body 17 shown in the right side of FIG. 3 at a distance in a direction perpendicular to the axis of the looper rocking shaft 16. One end of a substantially L-shaped crank arm 19 is rotatably attached to the tip.
A support pin 20 is provided at the other end of the crank arm 19.
The tip of the support pin 20 is rotatably mounted.
Is projectingly provided at a substantially central portion in the longitudinal direction of the looper table 21. Further, a known looper 8 having a hook 8a at its tip for capturing one needle thread 2a is attached to the tip of the looper base 21 shown in the upper part of FIG.

That is, the rotation of the lower shaft 10 is converted into a rocking motion and transmitted to the looper 8 by the looper rocking body 17, the eccentric pin 18 and the crank arm 19.

At the lower end of the looper base 21, a pair of left and right shaft attachment portions 22, 22 are formed, and holes 23 are formed in the shaft attachment portions 22, 22, respectively. Have been. A looper support shaft 24 that supports the looper table 21 is provided so as to pass through each hole 23. As shown in FIG. 4, the looper support shaft 24 is moved vertically by a substantially elongated guide hole 26 formed in a looper support table 25 which is disposed so as to sandwich the looper table 21 therebetween. Are rotatably supported so as to be regulated. A main roller 27 as a cam follower that contacts a cam surface 32a of a later-described looper cam 32 for vertically moving the looper table 21 is rotatably attached to the looper support shaft 24. The main roller 27 is disposed between the pair of left and right shaft mounting portions 22 of the looper table 21.

A belt pulley 28 with driving teeth is attached to one end of the lower shaft 10 shown on the right side in FIG. A driven toothed belt pulley 29 paired with the driving toothed belt pulley 28 is disposed below the driving toothed belt pulley 28 in FIG. 3, and the driven toothed belt pulley 28 and the driven A toothed belt 30 is wound so as to be in contact with each outer peripheral surface of the toothed belt pulley 29.

The driven toothed belt pulley 29 is attached to the left end of the cam shaft 31 shown on the left side of FIG. 3, and the right end of the cam shaft 31 shown on the right side of FIG. A plate-shaped looper cam 32 for movement is attached. The looper cam 32 is provided with the main roller 27.
The cam surface 32a formed on the outer peripheral surface of the looper cam 32 is in contact with the outer peripheral surface of the main roller 27 from below.

Below the looper cam 32, there is attached a sub roller 33 for forcibly lowering the looper base 21 when the looper 8 is lowered by the looper cam 32, and is formed on the outer peripheral surface of the looper cam 32. The outer peripheral surface of the sub-roller 33 contacts the cam surface 32a thus formed from below. This sub roller 33 is provided with the camshaft 3
It is rotatably attached to a side surface near the lower end of a link plate 34 bridged between the loop member 1 and the looper support shaft 24. An elongated through hole (not shown) through which the camshaft 31 is inserted in the thickness direction is formed at the center of the link plate 34, and a looper support is provided near the upper portion of the link plate 34. A through hole (not shown) through which the shaft 24 is inserted in the thickness direction is formed. Note that the link plate 34 may be formed with a single elongated common through hole through which both the cam shaft 31 and the looper support shaft 24 can be inserted.

The thread swash back drive means 14 is disposed diagonally below and to the left of the output gear 12 in FIG. 3 and has a rotation ratio of 1: 2 to the output gear 12 via an idle gear 35, that is, 1/1/2 of the output gear 12. It has a spur gear-shaped large-diameter driven gear 36 for rotation which rotates in 2. This driven gear 3 for thread thread
Numeral 6 is attached to a left end portion shown on the left side of FIG. 3 of a thread slack shaft 37 rotatably supported inside a bed (not shown). The base end of a thread saw stand 39 is attached to the right end of the thread saw shaft 37 shown on the right side in FIG. 3 via an eccentric collar 38 fixed to the thread saw shaft 37 and eccentrically rotating. 3 is attached to the end of the thread saw stand 39 shown in the upper part of FIG. 3, which is provided with a hook 9a for catching one needle thread 2a.

In the vicinity of the tip of the thread saw stand 39,
A guide hole 40 formed in a substantially arc shape is formed, and a distal end portion of a guide pin 41 fixed to a support frame (not shown) is inserted into the guide hole 40.
The shape of the guide hole 40 can regulate the movement locus of the thread saw 9.

The output gear 12, the driven gear 15 for the looper, the idle gear 35, and the driven gear 36 for the thread sabaki.
A helical gear may be used, and the looper rocking body 17 and the crank arm 19 may be replaced with a form such as an eccentric collar 38 and a thread sabaki stand 39 to reduce noise during high-speed operation.

Further, the output gear 12, the driven gear 15 for the looper, the idle gear 35, and the driven gear 3
6 may be replaced with a belt transmission to further reduce noise during high-speed operation.

Further, the looper 8 and the thread saw 9
The lower shaft driving means 11 for driving
An actuator or the like operated by hydraulic pressure or the like may be controlled by the control means in conjunction with the vertical movement of the two hands 5a and 5b.

Next, the stitch forming operation of the present embodiment using the stitch forming apparatus of the present embodiment having the above-described configuration will be described with reference to FIGS.

FIGS. 5 to 12 show the stitch forming operation of the present embodiment using the stitch forming apparatus of the present embodiment, and FIG. 5 is an explanatory view showing a state after passing through the loop. 6 is an explanatory view showing a loop catching state, FIG. 7 is an explanatory view showing a loop catching passing state, FIG. 8 is an explanatory view showing a loop transfer state, and FIG. 9 is a view showing a state immediately before forming a single thread ring stitch. 10 is an explanatory view showing a state of forming a single thread ring stitch, FIG. 11 is an explanatory view showing a state after passing through a re-loop, and FIG. 12 is an explanatory view showing a state where a re-loop is captured. is there.

In the stitch forming apparatus 4 of the present embodiment, when the sewing machine starts, a sewing machine motor (not shown) is driven to start rotation of the upper shaft, and the rotation of the upper shaft is controlled by a known upper shaft driving means (not shown). Transmitted to the needle bar 6, and the needles 5a,
5b starts operation in conjunction with it. The rotation of the upper shaft is
It is transmitted to the lower shaft 10 by a known transmission mechanism (not shown),
The lower shaft 10 operates in conjunction with the upper shaft. At this time, the lower shaft 10
Rotates twice as much as the upper shaft, and the rotation of the lower shaft 10 is transmitted to the lower shaft driving means 11 via the output gear 12, and as a result, the rotation of the two hands 5a and 5b is linked. The looper 8 and the thread saw 9 start operating.

Then, with the rotation of the upper shaft, the two hands 5a, 5b descend in conjunction with the upper shaft, and the respective hands 5a, 5b
The needle thread 2a, 2b is positioned on the back of the cloth by penetrating, for example, a cloth as a sewing product (not shown). At this time, since the needles 5a and 5b are arranged stepwise, two needles 5a and 5b are provided.
The penetration resistance when penetrating the cloth can be reduced as compared with the case where a and 5b penetrate the cloth at the same time. FIG.
Needle tip and needle hole 5aa of one of the needles 5a forming the single thread ring stitch 1a located on the downstream side in the sewing direction indicated by arrow T
Are arranged above the needle tip and the needle hole 5ba of the other needle 5b forming the lock seam 1b located on the upstream side in the sewing direction indicated by the arrow T in FIG. 2, so that the lock seam 1b is formed. Needle thread 2b is a single thread ring stitch 1a
Is drawn out to the back of the cloth more than the needle thread 2a that forms

Next, as the rotation of the upper shaft progresses,
When each needle 5 rises, for example, by about 1 to 1.5 mm from the bottom dead center, the loops La, L of the needle threads 2a, 2b are formed by resistance of the cloth.
b is formed. At this time, since the needle thread 2b forming the lock seam 1b is drawn out more to the back of the cloth than the needle thread 2a forming the single thread ring seam 1a, the loop Lb of the needle thread 2b forming the lock seam 1b is The loop Lb of the needle thread 2b forming the lock seam 1b can be made surely larger than the loop La of the needle thread 2a forming the single thread ring seam 1a, and the loop Lb of the needle thread 2a forming the single thread ring seam 1a. It can be formed below the loop La.

Then, the needle thread 2a, 2b of each of the needles 5a, 5b
When the loops La and Lb are formed, the looper system driving means 13 which operates in conjunction with the lower shaft 10 which rotates at twice the speed of the upper shaft, causes the eccentric pin 18 to move the crank arm 19 to the left in FIG. Biasing the looper table 21 forward,
The looper cam 32 operates to lower the looper table 21 downward, whereby the looper 8 advances and descends toward the needle thread 2a, 2b on the back of the cloth, and the hook 8a of the looper 8 moves in the sewing direction. It passes through the inside of the loop Lb of the needle thread 2b forming the lock seam 1b located on the upstream side, and passes below the loop La of the needle thread 2a forming the single thread ring seam 1a located on the downstream side in the sewing direction. It becomes the state after passing through the loop. FIG. 5 shows the state after passing through the loop.

At this time, as shown in FIG. 5, the loop Lb of the needle thread 2b forming the lock seam 1b is larger than the loop La of the needle thread 2a forming the single thread ring seam 1a, and the lower part of the loop Lb is downward. , The loop 8, more specifically, the hook 8 a of the looper 8 is passed through the loop Lb of the needle thread 2 b forming the lock seam 1 b to form the loop of the needle thread 2 a forming the single thread ring seam 1 a It can be easily and reliably positioned below La.

Further, with the rotation of the lower shaft 10, the thread buckling drive means 14 pushes up the thread buckling stand 39 to advance the thread buckling 9 toward each of the loops La and Lb. The operating speed of the looper 8 is slowed down by the driven gear 36 for the thread slack. More specifically, since the thread slack 9 operates at a half speed of the looper 8, the thread slack 9 is formed by the loops La and Lb of the loops La and Lb. Does not reach the forming position.

Then, as the rotation of the upper shaft progresses, the rotation of the lower shaft 10 progresses in conjunction therewith, and the looper 8 retreats and rises by the looper system driving means 13 so that the hook 8a of the looper 8 moves downstream in the sewing direction. The loop La of the needle thread 2a forming the single thread ring seam 1a located on the side is hooked from below to catch the loop, and a loop catching state is obtained. FIG. 6 shows this loop capture state.

Then, as the rotation of the upper shaft progresses, the rotation of the lower shaft 10 progresses in conjunction therewith, and the looper 8 continues the retreating motion to form the loop La of the needle thread 2a forming the single thread ring seam 1a. In the captured state, the needle thread 2b that forms the lock seam 1b passes through the loop Lb inside the loop. At this time, the loop Lb of the needle thread 2b forming the lock seam 1b
Is formed so that the loop La of the loop La of the needle thread 2a forming the single thread ring seam 1a easily passes through the loop Lb of the needle thread 2b forming the lock seam 1b. Becomes This loop capture passing state is shown in FIG.

Then, as the rotation of the upper shaft further proceeds, the two hands 5a, 5b rise toward the top dead center, and each of the loops La, Lb tries to be pulled up to the cloth surface. The loop La of the needle thread 2a forming the single thread seam 1a is held by the looper 8 on the back of the cloth, and the loop Lb of the needle thread 2b forming the other lock seam 1b is the needle thread forming the single thread ring seam 1a. The loop La of the thread 2a is fastened at the upstream side in the sewing direction at a distance Pb from the binding part 3 of the single thread ring stitch 1a. At this time, the looper 8 continues to retreat,
When the looper 8 retreats, the loop La of the needle thread 2a forming the single thread ring stitch 1a captured and held by the looper 8 is detached from the looper 8 by the advancing thread saw 9 and the hook of the thread saw 9 9a catches and holds the loop La detached from the looper 8, and thereafter, the thread saw 9 starts retreating.

That is, the loop La of the needle thread 2a forming the single thread ring stitch 1a is delivered from the looper 8 to the thread saw 9 and is in a loop delivery state. This loop transfer state is shown in FIG.

While the loop La is being transferred from the looper 8 to the thread slack 9, the cloth is set at a predetermined interval Pa.
Is moved according to the feed pitch of, and is fed by one stitch.

Then, with further progress of the rotation of the upper shaft, the two needles 5a and 5b descend again after reaching the top dead center, and the needles 5a and 5b move the cloth as a sewing product (not shown). Each of the needle threads 2a and 2b penetrates and is positioned on the back of the cloth. At this time, the two needles 5a and 5b and the thread slack 9 holding the loop La which is one stitch before the needle thread 2a forming the single thread ring seam 1a are located below the needle hole of the needle plate (not shown). The needle 5a that meets the back of the cloth and forms the single thread ring seam 1a is located inside the loop La one needle before the needle thread 2a that forms the single thread ring seam 1a held by the thread saw 9 and is locked. The needle 5b forming the stitch 1b is positioned outside the upstream side in the sewing direction of the loop La held by the thread saw 9 and is in a state immediately before the formation of the single thread stitch. FIG. 9 shows a state immediately before the formation of the single thread ring stitch.

That is, the thread saw 9 is provided at least one stitch later in the loop La of the needle thread 2a of the needle 5a forming the single thread stitch 1a captured by the looper 8.
a can be held until the needle thread 2a of the needle 5a forming the position a is located.

Then, as the rotation of the upper shaft further proceeds, the two hands 5a, 5b descend toward the bottom dead center, and before the two hands 5a, 5b reach the bottom dead center, The thread Sabaki 9 further retreats, and the previous loop La held by the thread Sabaki 9 separates from the thread Sabaki 9 and wraps the needle thread 2a of the needle 5a forming the single thread ring seam 1a located on the back of the cloth. As a result, the first single thread ring stitch 1a held by the needle 5a is formed. That is, the needle thread 2 forming the single thread ring seam 1a
a is located inside the loop La of the needle thread 2a forming the single thread ring seam 1a one stitch before. FIG. 10 shows the formation state of the single thread ring seam.

Then, when the two needles 5a, 5b slightly rise from the bottom dead center with further progress of the rotation of the upper shaft, a new loop is formed on the needle thread 2a, 2b of each of the needles 5a, 5b. While La 'and Lb' are formed, the looper 8 advances and descends again, and the hook 8a of the looper 8 forms a new loop Lb 'of the needle thread 2b forming the lock seam 1b located on the upstream side in the sewing direction. After passing through the inside of the new loop La 'of the needle thread 2a forming the single thread ring stitch 1a located on the downstream side in the sewing direction. FIG. 11 shows the state after the re-loop.

Then, as the rotation of the upper shaft progresses, the rotation of the lower shaft 10 progresses in conjunction therewith, and the looper 8 retreats and rises by the looper system driving means 13 so that the hook 8a of the looper 8 moves downstream in the sewing direction. A new loop La 'of the needle thread 2a forming the single thread ring stitch 1a located on the side is hooked from below to catch the loop, and the state becomes the re-loop catching state. This re-loop capture state is shown in FIG.

The loop transfer state shown in FIG. 8, the state immediately before the formation of the single thread stitch shown in FIG. 9, the formation state of the single thread stitch shown in FIG. 10, the state after passing through the re-loop shown in FIG. 11, and the state shown in FIG. By repeating the re-loop capture state shown in this order, the seam 1 of the present embodiment in which the single thread ring seam 1a and the lock seam 1b shown in FIG. 1 are combined can be continuously formed.

According to the stitch forming apparatus 4 of the present embodiment having such a configuration, by using two needles 5a and 5b, a needle thread for forming a single thread ring stitch 1a called a thread path is provided. The thread path of the needle 2a and the thread path of the needle thread 2b forming the lock stitch 1b can be formed independently, and the sewing operation can be performed in a form in which the two needles 5a and 5b are arranged in parallel. In addition, it is possible to reliably prevent twisting of the needle threads 2a, 2b and winding of the needle threads 2a, 2b around the needles 5a, 5b. Sewing product quality can be maintained.

Since two needle threads 2a and 2b can be used individually for the two needles 5a and 5b, the conventional one
Compared to the seam using two needle threads with two needles, the needles 5a,
It is possible to reduce both the penetration resistance when the 5b penetrates the cloth and the size of the through hole when the needles 5a and 5b penetrate the cloth, and to stabilize the loops La and Lb of the needle threads 2a and 2b. Can be. As a result, it is possible to reliably prevent stitches from skipping in the seam 1 and to maintain high sewing product quality. In addition, since the through holes when the needles 5a and 5b penetrate through the cloth can be made smaller than before, the sewing holes are small but the sewing marks are small, so that they can be used for sewing leather products.

Further, since the two needle threads 2a and 2b can be used individually for the two needles 5a and 5b, the two needle threads 2a and 2b can be used with different yarn counts and combinations. , Even when thick yarn and thin yarn are used, each needle yarn 2a,
The loops La and Lb of the line 2b are stabilized, and it is possible to reliably prevent stitches from skipping in the seam 1 and to maintain high sewing product quality.

Since the two needles 5a and 5b used in the seam forming device 4 of the present embodiment are generally commercially available, the needles 5a and 5b can be easily obtained. It is also inexpensive.

Further, the seam forming device 4 of the present embodiment
According to the above, the two needles 5a, 5b,
The seam 1 is formed by the lower shaft driving means 11 which operates the looper 8 and the thread saw 9 in conjunction with the vertical movement of the two needles 5a and 5b, so that the structure is simple and the manufacturing is simple. In addition to being easy, it is possible to surely reduce the cost, that is, the economical burden.

Furthermore, according to the seam forming device 4 of the present embodiment, the interval NP between the two needles 5a and 5b is
Is changed by exchanging the
Since the interval Pb between the binding portion 3 of the single thread ring stitch 1a formed by one needle thread 2a and the position where the single thread ring stitch 1a is threaded by the other needle thread 2b can be easily adjusted, the entirety can be adjusted. It is possible to easily change the pattern of the stitches formed by the two needles 5a and 5b arranged in a line as necessary according to the type of sewing product.

Further, according to the stitch forming apparatus 4 of the present embodiment, the drive source of the lower shaft drive means 11 is a sewing machine motor for driving the upper shaft drive means, ie, one drive source Since the upper shaft drive means and the lower shaft drive means 11 are formed so as to be drivable, the economic burden can be further reduced and the cost can be reduced. The present invention is not limited to the embodiment, and can be changed as needed.

[0078]

As described above, according to the seam of the present invention, it is possible to perform a long-time sewing operation efficiently, and it is possible to prevent skipping and to maintain a high quality of a sewn product. It has the effect. Further, according to the seam forming device of the present invention, it is possible to form the seam of the present invention reliably and easily, and it is possible to reduce the economic burden.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a seam according to the present invention.

FIG. 2 is a front view showing an attached state of a needle in the embodiment of the seam forming device according to the present invention;

FIG. 3 is a perspective view showing a configuration of a main part of the embodiment of the seam forming apparatus according to the present invention.

FIG. 4 is a perspective view showing the vicinity of a looper support of the embodiment of the seam forming apparatus according to the present invention.

FIG. 5 is an explanatory diagram showing a state after a loop of a stitch forming operation of the present embodiment using the stitch forming apparatus of the present embodiment;

FIG. 6 is a view similar to FIG. 5, showing a loop capturing state of a stitch forming operation of the present embodiment using the stitch forming apparatus of the present embodiment;

FIG. 7 is a view similar to FIG. 5, showing a loop capture passing state of a stitch forming operation of the present embodiment using the stitch forming apparatus of the present embodiment;

FIG. 8 is a view similar to FIG. 5, showing a loop transfer state of the stitch forming operation of the present embodiment using the stitch forming apparatus of the present embodiment;

FIG. 9 is a view similar to FIG. 5, showing a state immediately before formation of a single thread stitch in a stitch forming operation of the present embodiment using the stitch forming apparatus of the present embodiment;

FIG. 10 is a view similar to FIG. 5 showing a state of forming a single thread ring stitch in a stitch forming operation of the present embodiment using the stitch forming apparatus of the present embodiment;

FIG. 11 is a view similar to FIG. 5, showing a state after a re-loop of a stitch forming operation of the present embodiment using the stitch forming apparatus of the present embodiment;

FIG. 12 is a view similar to FIG. 5, showing a re-loop capture state of a stitch forming operation of the present embodiment using the stitch forming apparatus of the present embodiment;

FIG. 13 is an explanatory view showing a stitch that enables long-time sewing work using two conventional needle threads.

[Explanation of symbols]

Reference Signs List 1 stitch 1a single thread ring stitch 1b lock stitch 2a needle thread (forming a single thread ring stitch) needle thread 2b (forming a lock stitch) needle thread 3 (single thread ring stitch) binding part 4 stitch forming device 5a (single thread Needle 5b (to form a lock seam) Needle 5aa (to form a lock seam) Needle hole 5ba (to form a lock seam) Needle hole 5ba (to form a lock seam) 6 Needle bar 7 Needle clamp 8 Looper 9 Thread Sabaki 10 Lower Shaft 11 Lower Shaft Driving Means 13 Looper Driving Means 14 Thread Sabaki Driving Means La, La '(for needle thread forming single thread ring seam) Loop Lb, Lb' (lock seam is formed) Loop of needle thread Pa Pa (Between tying portions forming the pitch of single thread ring stitch) Pb (Bundling of single thread ring stitch where lock stitch is a position where single thread ring stitch is tightened with cloth back Department ) Intervals NP (2 needles) interval T sewing direction

Claims (7)

[Claims] 1. A stitch having a single thread ring stitch formed by one of two needle threads, and a lock stitch formed by another needle thread of the two needle threads. A seam characterized in that a thread is fastened to the single thread ring seam by the lock seam on an upstream side in a sewing direction from a binding portion of the single thread ring seam. 2. A needle thread for forming a single thread ring seam can be supplied, and the other thread needle for forming a lock seam can be provided in parallel in a sewing direction at intervals. It is provided with two needles which can be supplied and can reciprocate up and down, respectively, and a needle bar to which the two needles are attached. An upper shaft driving means for reciprocating the needle; and a needle thread loop of one of the needles located on the downstream side in the sewing direction formed on the back of the cloth in conjunction with the vertical movement of the two needles in the sewing direction. A looper that can be captured by passing through the inside of the loop of the needle thread of the other needle located on the side, and the one loop after at least one stitch inside the loop of the needle thread of the one needle captured by the looper A thread sabaki that can be held until the needle thread of the needle is positioned, the looper and the thread Stitch forming apparatus characterized by having a lower shaft system driving means for operating with the spreader in conjunction with the vertical motion of the two needles. 3. The seam forming apparatus according to claim 2, wherein the needle points of the two needles are arranged stepwise. 4. A needle tip and a needle hole of one of the needles located on the downstream side in the sewing direction are arranged above the needle tip and a needle hole of the other needle located on the upstream side in the sewing direction, respectively. The seam forming device according to claim 3, wherein: 5. The seam forming apparatus according to claim 2, wherein a distance between the two needles is variable. 6. The stitch forming apparatus according to claim 5, wherein an interval between the two needles is made variable by exchanging a needle pin. 7. The apparatus according to claim 2, wherein the upper shaft drive unit and the lower shaft drive unit are drivable by a single drive source. Seam forming device.