JPH07289765A - Thread cutting device for sewing machine - Google Patents

Abstract

PURPOSE:To make possible to cut needle thread and bobbin thread in adjacency of the needle location point and upon the shuttle and to shorten the thread length left on sewn goods, by constituting a first member with a thread catching part and a second member with an edge and arranging them horizontally movable upon the shuttle respectively. CONSTITUTION:A cutting lever 4, the first member, is installed on a picker base 8, the second member, via a supporting shaft 6 rotatable in vertical direction. Fixed edges 2 and 10 to cut upper thread and bottom thread respectively are installed on the sides of the picker base 8. A picker base setting bed 14 is fixed on an oscillating shaft 18 and the oscillating shaft 18 is supported together with a first solenoid 120 rotating on a first oscillation arm 121 by a driving shaft 127 to rotate a cam 123 engaging with a second oscillating shaft 122. On the other hand, a cutting lever driving shaft 20 is installed on the oscillating shaft 18 in a way possible to move vertically and the oscillation arm 124 is linearly reciprocated by a second solenoid 125. The needle thread and the bobbin thread are cut by reciprocating the picker base 8 and moving the cut lever 4 vertically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread cutting device for a sewing machine.

[0002]

2. Description of the Related Art Conventionally, as a cutting device for upper and lower threads of a sewing machine, those shown in FIGS. 23 and 24 have been known.

The cutting device shown in FIG. 23 scoops and cuts the upper thread 203 and the lower thread 206 by means of a moving blade 204 which makes a linear reciprocating motion in a horizontal plane between a feed (not shown) and the inner hook 202. Is.

In the cutting device shown in FIG. 24, the upper thread 203 and the inner hook 20 which have been moved to the upper surface of the inner hook 202 by the moving blade 204 which rotates and swings in the horizontal plane on the inner hook 202.
The lower thread 206 arranged on the upper surface of 2 is scooped and cut.

FIG. 25 is a perspective view of a conventional thread cutting device of the type shown in FIG. A moving knife base 210 is fixed to a drive shaft 208 rotated by a driving source (not shown), and a moving knife 212 is fixed to the moving knife base 210.

When the drive shaft 208 rotates, the moving knife 212
Rotates reciprocally above the shuttle 214 around the drive shaft 208 as a fulcrum. By this rotational movement, the tip of the moving knife 212 catches the lower thread as shown in FIG.
The yarn is pulled in the direction of 6, and when the blade portion 218 of the moving knife 212 coincides with the fixed knife 216, the yarn is cut at the point T. At this time, the lower thread bobbin case side cut end is the lower thread clamp spring 22.
It is sandwiched between 0 and held for the start of the next sewing. In addition,
The fixed knife 216 and the bobbin thread clamp spring 220 are fixed to the fixed knife base. Thus, in the conventional device, the lower thread clamp spring 220 is integrated with the fixed knife 216. 224 is a feed dog, 226 is a needle hole, and 228 is a needle plate.

FIG. 27 is a perspective view showing a sewn product after thread cutting. The root of the thread piece remaining in the sewn product 228 is P, and the cutting destination is T
Then, the path from P to T in FIG. 25 determines this length L.

In any of the devices, when a thread cutting signal is output from an electric machine control system (not shown), the solenoid is energized from the electrical system, and the movable blade 204 is rotated and reciprocated by the solenoid or the cam. The upper thread 203 and the lower thread 206 are captured during the backward movement of the moving blade 204, and when the backward movement is completed, the moving blade 204 is brought into alignment with the fixed blade 222 to cut the yarn. These series of operations are performed during the operation of the sewing machine between the preset lower position stop position and the preset upper position stop, and therefore are executed with the rotation of the sewing machine.

[0009]

[Problems to be Solved by the Invention] In the sewing process,
In order to make the finish of the sewn product beautiful and to improve work efficiency, it is required to shorten the remaining length of the thread piece as a thread trimming function of the sewing machine. There is. If the remaining length of the thread piece is too long, a problem such as a thread ball being formed in the seam at the beginning of sewing occurs.

The position of the cutting point T depends on the mounting position of the fixed knife 216, but the fixed knife 216 and the bobbin thread clamp spring 220 hinder the movement of the thread between the needle hole and the shuttle due to the sewing operation of the sewing machine. You need not to. Therefore, in the conventional thread cutting device, the needle hole 2 of the feed dog 224 is
Must be placed at a certain distance from 26,
After all, the length L of the thread piece remaining on the sewing object after thread cutting (see FIG. 27).
(See) becomes long.

Even if the distance between T and P can be shortened in order to shorten L, the length of the lower thread to be held is short, so that the upper thread 203 is less likely to be entangled at the next sewing start, and the stitch There is also a problem in that it cannot be formed.

Further, in the conventional thread cutting device, the thread is cut during the operation of the sewing machine, so that the behavior of the thread is accompanied and the remaining length of the needle side upper thread after the cutting varies. If the remaining length of the needle side upper thread is too short, the next stitch cannot be formed, and if it is too long, a thread ball will be formed in the stitch at the beginning of sewing. Therefore, an object of the present invention is to provide a thread cutting device for a sewing machine having a predetermined upper thread length after cutting, which can solve the above problems.

[0013]

In order to solve the above object, according to the present invention, a first member having a yarn catching portion and a second member having a blade are provided, and both the first and second members are provided. Provided is a thread cutting device for a sewing machine, which is movable in a horizontal direction above a shuttle.

Preferably, the upper and lower yarns are caught by the yarn catching portion of the first member, and the first member and the second member are moved above the shuttle to cut the upper and lower yarns. Preferably, the bobbin thread cutting end is caught by the thread catching portion of the first member, and the bobbin thread cutting end is released at the beginning of sewing.

Preferably, the first member and the second member can be opened and closed in the vertical direction, and the upper and lower yarns are cut between the first member and the second member when closed.

More preferably, the first member and the second member can be opened and closed horizontally, and the upper and lower threads are cut between the first member and the second member when closed.

More preferably, the first member and the second member are linearly movable in the horizontal direction, and the upper and lower threads are cut between the first member and the second member.

More preferably, the upper and lower threads are caught before the upper thread passes over the hook, and after the upper thread is removed from the hook by the rotation of the hook, the dropped upper and lower threads are caught and cut.

[0019]

In the thread cutting device of the sewing machine according to the present invention, both the first member having the thread catching portion and the second member having the blade can be moved horizontally in the upper part of the hook, so that the upper and lower threads can be moved near the needle drop point. Can be cut. Further, the lower thread cutting end is caught by the thread catching portion of the first member, and the lower thread cutting end is released at the start of sewing. Therefore, the length of the needle side upper thread can be sufficiently secured, so that there is no trouble such as the fact that a stitch cannot be made at the time of the next sewing.

[0020]

1 to 5 show a first embodiment of a thread cutting device for a sewing machine according to the present invention, FIG. 1 is an overall perspective view, and FIG. 2 (a) is a sectional view taken along line XX of FIG. 2 (b) is a sectional view showing only the cutting blade when opened, FIG. 3 (a) is a perspective view of the thread cutting fixed blade, and FIG. 3 (b) is a perspective view of the cutting lever. 4 and 5 show the same embodiment at the thread cutting position.
(A) is a perspective view of the lower thread cutting fixed blade 2, (b) is a perspective view of the cutting lever 4, (a) is a perspective view of the thread cutting device, and (b) is a cutting lever. It is a perspective view.

In these drawings, 4 is a cutting lever (first member), 8 is a picker base (second member), and the cutting lever 4 is vertically pivotable via a fulcrum shaft 6 so as to be vertically movable. Installed to. A fixed blade 2 for cutting the lower thread and a fixed blade 10 for cutting the upper thread are attached to the side surface of the picker base 8. At the lower end of the lower thread cutting fixed blade 2, there is provided a protrusion 12 for ensuring the upper thread length.

The picker base 8 is a picker base mount 14
It is fixed by a screw 16 and can be easily removed by loosening the screw 16. The picker base mounting base 14 is fixed to a rotatable swing shaft 18, and the swing shaft 1
The rotation of 8 causes a swinging motion in the horizontal direction. Swing shaft 18
Has a first swing arm 121 and a second swing arm 122,
The swing shaft 18 is a first swing arm that swings the first swing arm 121.
The drive shaft 1 that rotates the cam 123 that engages with the second swing arm 122 together with the solenoid 120 (actuator).
It is rotatably supported by 27. The drive shaft 127 is interlocked with the main shaft of the sewing machine via the lower shaft of the sewing machine. A cutting lever drive shaft 20 is attached to the swing shaft 18 so as to be vertically movable. A screw 22 is provided at the upper end of the cutting lever drive shaft 20, and the cutting lever 4 is engaged with the screw 22. A drive arm 124 is fixed to the lower portion of the cutting lever drive shaft 20. The drive arm 124 has its center portion pivotally supported by the machine frame of the sewing machine, one end thereof is fixed to the cutting lever drive shaft 20, and the other end thereof is supported by a second solenoid (actuator) 125 capable of linearly reciprocating. . When the second solenoid (actuator) 125 moves up and down, the cutting lever drive shaft 20 also moves up and down, and the cutting lever 4 rotates up and down about the fulcrum shaft 6.

The tips of the lower thread cutting fixed blade 2 and the upper thread cutting fixed blade 10 are cutting blades. As shown in FIG. 2, angles α and β are provided at the lower and leading edges of the cutting blades of the lower thread cutting fixed blade 2 and the upper thread cutting fixed blade 10. Therefore, when the cutting lever drive shaft 20 moves downward and the tip of the cutting lever 4 rotates upward, the fixed blades 2 and 10 and the cutting blades 28 and 3 move.
The thread can be cut between 0.

At the tip of the cutting lever 4, the lower thread catching projection 24 for catching the lower thread 36 from the lower thread outlet 37 provided in the inner hook and the upper thread 38 for catching the upper thread 38 extending from the needle 41 are provided. A catching protrusion 26 is provided, and cutting blades 28, 30 are provided at the front end. Further, the lower thread clamp spring 32 for holding the lower thread 36 is provided on the upper surface of the cutting lever 4.
Is provided. This bobbin thread clamp spring 32 has a screw 3
3, the spring pressure can be adjusted.

As described above, in the thread cutting device of the first embodiment, the thread cutting portion and the lower thread holding portion for the next sewing are integrally provided.

FIG. 6 shows a first solenoid for rotating the picker base mounting base 14 and a second solenoid for vertically moving the picker base 8 and the cutting lever drive shaft 20 in accordance with the rotation of the picker base mounting base 14. 3 is a timing chart showing the operation curve of the solenoid of FIG. 3 together with the movement curves of the needle bar of the sewing machine, the balance, and the shuttle. Unlike the conventional example, this timing chart is a timing chart during the thread cutting operation after the sewing operation of the sewing machine is completed.

7 to 10 are views showing a series of operations associated with the rotation of the swing shaft 18. FIG. 7 shows a state in which the picker base 8 is in an initial (standby) position, and FIG. 9 shows a state in which the picker base 8 has moved to the forward position, FIG. 9 shows a state in which the picker base 8 has moved to the cutting position to cut the thread, and FIG. 10 shows a state in which the picker base 8 has returned to the initial position after cutting the thread.

As shown in these figures, the picker base 8
Etc. are arranged on the shuttle 34 so as to be horizontally rotatable.
During operation of the sewing machine, the picker base 8 is in the initial position shown in FIG. At this time, the cutting lever drive shaft 20 is in a state of moving upward, and the cutting lever 4 has its tip lowered about the fulcrum shaft 6 and the blades 28, 30 are opened. In the figure, 4
Reference numeral 0 is a needle plate, 42 is a feed dog, 44 is a needle, and 46 is a needle drop point.

The thread cutting device of this embodiment operates after the sewing operation of the sewing machine is completed. Figure 6 after the sewing operation of the sewing machine is stopped
As shown in, a thread trimming signal is output from an electric machine control system (not shown) at the needle stop position. In synchronization with this thread trimming signal, the first solenoid and the second solenoid are energized for a certain period of time or a certain phase of spindle rotation.

As a result, the swing shaft 18 is driven by the first solenoid to move the picker base 8 from the initial position to the most advanced position shown in FIG. The second solenoid lowers the cutting lever drive shaft 20 and raises the cutting lever 4 to close the blades 28 and 30. A cam or the like can be used instead of the first solenoid. In this way, when moving from the initial position to the most advanced position of FIG.
4 moves the upper part of the lower thread 36 coming out of the shuttle 34, so that the lower thread 36 is not locked.

Thereafter, the cutting lever drive shaft 20 moves upward, and the tip of the cutting lever 4 moves downward to move the blades 28, 30.
The picker base 8 moves back from the most advanced position in FIG. 8 to the cutting position in FIG. During this movement, the lower thread 36 is captured by the lower thread capturing projection 24 of the cutting lever 4 as shown in FIG.

As shown in FIGS. 5A, 8 and 9, the cutting position is the needle drop point 46 and the rotation center of the swing shaft 18 (screw 2).
The line segment L connecting 2) and the center line M of the cutting lever 4 are located at the same position.

Stop the movement of the picker base 8 at the operating position,
Wait for the upper thread 38 to cross the hook. The upper thread 38 is drawn by the balance and is caught by the protrusion 12 at the lower end of the lower thread cutting fixed blade 2 (FIG. 4 (a)), but when the upper thread 38 is further drawn by the balance, it is removed from the hook and the cloth side. The upper thread 38a is caught by the upper thread catching protrusion 26 of the cutting lever 4 (FIGS. 9 and 4).
(B)). That is, since the needle thread that has passed through the hook and drawn on the balance is locked by both the protrusion 12 and the needle thread catching protrusion 26 of the fixed blade for cutting the lower thread, the needle side needle thread after thread cutting has a predetermined length. .

This state is maintained until the upper stop position of the sewing machine as shown in the timing chart of FIG. At the upper stop position, the second solenoid is energized to move the cutting lever drive shaft 20 downward to raise the cutting lever 4.

As a result, the cutting blade 28 of the cutting lever 4,
30, the fixed thread 2 for cutting the lower thread, and the fixed blade 10 for cutting the upper thread match, and the cloth side upper thread 38a and the lower thread 36 captured by the cutting lever 4 are cut. FIG. 5 shows the cut state. Simultaneously with the cutting, only the shuttle-side lower thread cutting end 36 is held between the lower thread clamp spring 32 and the upper surface of the cutting lever 4.

As shown in FIG. 10, the picker base 8 is returned from the cutting position to the standby position by the first solenoid while the lower thread 36 is held. The clamp pressure by the lower thread clamp spring 32 is adjusted to be larger than the lower thread press tension by the bobbin case by the adjustment by the lower thread clamp spring 32. Therefore, the bobbin thread 36 is pulled out from the inner hook bobbin thread outlet when the picker base 8 moves from the cutting position to the standby position. At the time of returning to the standby position, the second solenoid is de-energized, the cutting lever drive shaft 20 is moved upward, the holding state of the lower thread is released, and the machine waits for the next sewing.

In this embodiment, after the sewing machine has made one cycle and stopped, the picker base 8 returns from the standby position to the most advanced position, the cutting position, and then to the standby position again.

The sewing machine stop in the above description may be not only the sewing machine stop in the normal sewing but also the sewing machine stop in the backward sewing, and the thread is always cut after the sewing machine is stopped.
The lower thread 36 is paid out and the picker base 8 is returned to the standby position. Further, the cutting position is not limited to the position where the line segment L connecting the needle drop point 46 and the rotation center of the swing shaft 18 and the center line M of the cutting lever 4 coincide. That is, after the upper and lower yarns are captured (the cutting position at which the cloth-side yarn remains are the minimum), the swing shaft 18 can be rotated to cut at a predetermined position. As a result, the length of the thread piece remaining on the sewn product can be adjusted freely. According to the first embodiment, the following effects can be obtained.

(1) Unlike the conventional thread cutting device in which the movable blade and the fixed blade move in different horizontal directions, the two blades integrally move in the horizontal direction, so that the thread on the cloth side It is possible to cut at the position of the minimum length, the thread picking step after thread cutting can be eliminated, and productivity is improved.

(2) Since the upper thread 38 is held by the projection 12 of the fixed thread 2 for cutting the lower thread and the upper thread 38 is cut, the needle-side upper thread 38a can have a sufficient length, so that the next stitch At the time of, there is no trouble such as not being able to stitch. (3) Since the lower thread 36 is not pressure-held at the time of the next sewing, the finish at the beginning of sewing becomes beautiful.

(4) By separating the operation operation of the sewing machine and the thread cutting operation, the next sewing that is caused by tensioning the thread with the moving blade for thread cutting during the operation of the sewing machine as in the conventional thread cutting device. The skipping at the beginning and the variation in the remaining length of the needle side upper thread are improved, and the productivity is greatly improved.

Next, a second embodiment of the thread cutting device for a sewing machine according to the present invention will be described. FIG. 11 is an exploded perspective view of the yarn cutting device according to the second embodiment. In the drawing, 50 is a thread separating base, and the supporting holes 50a and 50b are provided in the thread separating base 50.
Thus, the yarn handling arm shaft 52 and the yarn handling drive shaft 54 are rotatably attached. And thread separation base 5
0 is adjustably fixed to the shuttle shaft base 12 by screws 133, 133 and elongated holes 50c, 50c provided in the base 50.

A thread-separating arm 56 is attached to the thread-separating arm shaft 52.
It is attached so as to be rotatable around the yarn handling arm shaft 52. A moving knife guide pin 58 is attached to the thread separating arm 56.
Is fixed.

A thread separating member 60 is fixed to the thread separating shaft 54 by screws 62 and 64. Therefore, the thread handling unit 60 is rotatable around the thread handling drive shaft 54.

The moving knife shaft 6 is attached to the thread separating member (first member) 60.
6 is fixed, and the moving knife (second member) 68 is provided rotatably around the moving knife shaft 66. The thread separating drive shaft 54 includes a hole 50b of the thread separating table 50 and rings 130, 13 for supporting the drive shaft in the vertical direction thereof.
0 and screws 131, 131 are supported so as to be vertically movable.

Long grooves 60A and 68A are provided on the thread separating member 60 and the moving knife 68, respectively, and the moving knife guide pin 58 penetrates these long grooves 60A and 68A. The yarn handling drive shaft 54 is rotated by a drive source (not shown), and the yarn handling 6
When 0 rotates around the thread separating drive shaft 54, the moving knife 6
8 is moved by being guided by the moving knife guide pin 58, and the long grooves 60A and 68A are formed in such a shape that the yarn separating drive 60 and the moving knife 68 are opened and closed in the horizontal direction by the rotation of the thread separating drive shaft 54. There is.

As described above, the yarn handling arm 56 connects the yarn handling drive shaft 54, the yarn handling 60, and the moving knife 68.
Since the tip end of the thread separating member 60 is provided with a concave portion 60B into which the upper and lower threads 84 and 86 are inserted and an inclined blade surface 60C, and the blade portion 68B is provided at the tip of the moving knife 68, the upper and lower threads are provided in the concave portion 60B. When the both are closed while the 84 and 86 are captured, the upper and lower threads 84 and 86 are cut.

The lower thread clamp spring 7 is attached to the tip of the moving knife 68.
0 is fixed. The lower thread clamp spring 70 is provided with a predetermined gap between the lower thread clamp spring 70 and the moving knife 68, and the thread separating member 60 can be inserted into this gap.

A lower presser pin 72 is fixed to the lower surface of the tip end portion of the thread separating unit 60, and a lower presser 74 is attached to the outer periphery of the lower presser pin 72.

12 to 14 are views showing a series of operations accompanying the rotation of the yarn spreading drive shaft 54. FIG. 12A shows a state in which the thread separating unit 60 is in the initial (standby) position.
13B is a cross-sectional view taken along the line AA of FIG. 12A, and FIG. 13A is a state in which the thread separating member 60 is moved to the most advanced position.
13B is a sectional view taken along line BB in FIG. 13A, FIG. 14A is a state in which the yarn is moved to a cutting position, and FIG.
14A is a cross-sectional view taken along line CC of FIG. 14A, and FIG.
The partially expanded view of (a) is each shown.

In the initial position of FIG. 12, the thread separating unit 60 and the moving knife 68 are closed. The bobbin thread 84 extending from the shuttle to the needle hole is caught by the recess 60B of the thread separating member 60 while the thread separating member 60 moves from the initial position to the most advanced position in FIG. On the other hand, when the hook rotates, the upper thread 86 firstly moves the thread 6
It is captured in the concave portion 60E of 0. Further thread 86 crossing the hook
Is pulled up by a balance (not shown) of the sewing machine, the protrusions 60D are passed over, and the cloth side thread 86a is captured in the recess 60E. Thereafter, the thread separating member 60 rotates in the opposite direction and moves to the cutting position shown in FIG.

At the position shown in FIG. 14, the thread separating member 60 and the moving knife 68 are closed, and the blade surface 60C and the blade portion 68B coincide with each other at the position where the tips of the thread separating member 60 and the moving knife 68 are closest to the needle drop 78. 84 and 86 are cut.

In FIG. 14, 78 is the needle drop point and T is the cutting point. Since the cutting point T is closer to the needle drop 78 than the conventional cutting point, it is possible to shorten the length of the thread piece after cutting. In addition, after cutting, the thread separation 60 and the moving knife 6
No. 8 returns to the initial position so that it does not interfere with the sewing operation.

FIG. 15 is an enlarged view showing the ends of the thread separating member 60 and the moving knife 68 immediately after cutting, (a) is a perspective view,
(B) is the perspective view seen from the D direction of (a), (c) is sectional drawing.

Just before the thread is cut, the end of the bobbin thread coming out of the shuttle is sandwiched between the bobbin thread clamp spring 70 and the lower surface of the thread separating member 60 by the elasticity of the bobbin thread clamp spring 70. After that, the bobbin thread is sandwiched and held between the front end surface of the bobbin thread clamp spring 70 and the lower presser foot 74 at the time of cutting in FIG.

Thereafter, the bobbin thread 84 moves toward the initial position while being held by the thread separating member 60. With this movement, the bobbin thread 84 is pulled out from the hook as the distance between the thread separating member 60 and the hook lower thread outlet increases. Be done. Long groove 60A, 68
Due to the shape of A, the thread separating member 60 and the moving knife 68 are gradually opened and the holding of the lower thread 84 is loosened until the thread returns to the initial position shown in FIG.

The lower presser foot 74 of the second embodiment is shown in FIG.
As shown in (c), a chamfer 74 is formed at the base of the lower presser foot 74.
A is applied to make it easier to hold the lower thread. Further, the holding force can be improved by using an elastic material such as plastic as the material of the lower presser foot 74.

In the second embodiment, the threading drive shaft 54 is driven by a solenoid from the state shown in FIGS. 12 to 13 to the state shown in FIG. 13 through the state shown in FIG. Until it returns to the state, it is done by the cam. Further, the timing of the operation of these solenoids and cams can be made equivalent to the timing chart of the first embodiment described in FIG.

As described above, this embodiment is similar to the first embodiment in that both the first member (thread separating member 60) and the second member (moving knife 68) are horizontally rotatable. However, the difference is that the first member and the second member can be opened and closed horizontally instead of being opened and closed vertically. According to the second embodiment, the rings 130, 13
By changing the fixed position of 0, the vertical height of the first member and the second member can be adjusted. Further, when the relative position between the shuttle shaft base and the thread separating base 50 is changed by using the screw 133, the relative position of the moving knife guide pin 58 and the long grooves 60A, 68A via the thread separating arm shaft 52 and the thread separating arm 56. Because of the change, the thread cutting position and the standby position also change.
According to the second embodiment, the following effects can be obtained.

(1) Without using a conventional fixed knife, both the thread separating member 60 mainly for separating the thread and the moving knife 68 driven by the thread separating member 60 can be horizontally rotated to capture and cut the yarn. By doing so, the thread cutting point T can be set to a position near the needle drop point 78 of the feed dog. Therefore, the length of the thread piece remaining on the sewing object can be made short and stable. In addition, this eliminates the need for the work of processing the unnecessary thread of the sewing object.

(2) Even if the length of the bobbin thread 84 coming out of the shuttle as a result of cutting the bobbin thread at a position near the needle drop 78 becomes short, the bobbin thread 84 is pinched and held at the same time as the cutting and is pulled out. It is possible to secure a long length and make it easy for the seam to be formed at the start of the next sewing.

(3) The bobbin thread 84 after thread cutting can be reliably clamped. Third Embodiment Next, a third embodiment of the sewing machine thread cutting device of the present invention will be described. 16 is an exploded perspective view of the yarn cutting device of the third embodiment, FIG. 17 is a control plate of the embodiment of FIG. 16, (a) is a perspective view, and (b) is a front view.

In the drawing, 111 is a thread separating member (first member), and 112 is a moving knife (second member). Thread separation 1
A bobbin thread catching notch 111C, an upper thread catching notch 111D, and a cutting protrusion 111E are provided near the tip portion of 11. A cutting blade 112C is provided at the tip of the moving knife 112.

Further, a long hole 111A and a small hole 111B are formed in the thread separating member 111, and the small hole 11 is formed in the moving knife 112.
2A and the long hole 112B are formed. Threading 11
1 is fixed to the female mount 109 by a guide pin 110 passing through the small hole 111B. The female mount 109 is formed with a forked portion 109A and a protrusion 109B, and the drive pin 108 is fitted into the forked portion 109A through the long hole 111A and the small hole 112A. Therefore, when the drive pin 108 horizontally moves in the longitudinal direction of the moving knife 112, the moving knife 112
Slides in a horizontal direction with respect to the thread separating unit 111.

Reference numeral 102 denotes a control plate, which has a control groove 102A and holes 102B, 102 having a shape as shown in FIG. 17 (b).
C and 102D are formed. The drive pin 108 is fitted in the control groove 102A, and the shaft 109B of the female mount 109 is fitted in the hole 102B. The control plate 102 is fixed to the base 101 by screws 131 shown in FIG. The screw 130 fixes the base 101 and the shuttle shaft base.

Reference numeral 103 denotes a drive shaft that penetrates through the base 101 and has a forked portion 103A at the upper end. The converter 104 is rotatably attached to the base 101 via a shaft 113, and the converter 104 is provided with a forked portion 104A and a protrusion 104B for fitting with the forked portion 103A of the drive shaft 103. There is.

Reference numeral 105 denotes a drive arm, to which a drive link 106 is rotatably attached via a step screw 107. The drive arm 105 is formed with a projection 105A that fits into the forked portion 104A of the converter 104.

Holes 105B and 106A are formed in the drive arm 105 and the drive link 106, respectively. Hole 10
The shaft 109B of the female mounting base 109 is fitted in 5B, and the drive pin 108 is fitted in the hole 106A. In addition,
The drive shaft 103, the hole 105B, the protrusion 109B, and the guide pin 110 are provided so as to be aligned.

In the above structure, when the drive shaft 103 is rotated by a drive source (not shown), the conversion body 104 is rotated around the shaft 113 via the bifurcated portion 103A and the protrusion 104B, and the conversion body 104 is rotated. Rotational movement is forked part 104A,
Although transmitted to the drive arm 105 via the protrusion 105A, the drive link 106 rotatably connected to the drive arm 105 is guided by the movement of the drive link 106 according to the shape of the control groove 102A engaging with the drive pin 108. Non-through hole 105
The end portion on the B side and the end portion on the non-through hole 106A side of the drive link 106 perform opening / closing movement.

18 to 21 are plan views showing a series of operations accompanying the rotation of the drive shaft 103, and FIG.
11 and the moving knife 112 are in the initial (standby) position,
FIG. 19 shows a state in which the thread separating unit 111 and the moving knife 112 have moved to the most advanced position, and FIG. 20 shows a thread separating unit 111 and the moving knife 1.
FIG. 21 shows a state in which 12 moves to the cutting position and cuts the thread, and FIG. 21 shows a state in which the thread separating 111 and the moving knife 112 have returned to the initial position after cutting the thread. 22 is a partially enlarged perspective view of FIG.

In the initial position of FIG. 18, the drive arm 1
05, the drive link 106 is open, and the cutting blade 112C of the moving knife 112 projects forward from the tip of the thread separating unit 111. In FIG. 18, the straight line L1 is the drive shaft 10
3 is a line segment connecting 3 and the protrusion 104B.

The drive shaft 103 is rotated by a predetermined angle from the position shown in FIG. 18 by a drive source (not shown) to obtain the state shown in FIG. 19. However, when the line segment connecting the drive shaft 103 and the projection 104B in FIG. 19 is L2. , L1 and L2 form an angle α1 which is the rotation angle of the drive shaft 103 from the initial position. When the drive pin 108 moves from the initial position to the most forward position in this way, the drive pin 108 moves from the position a to the position e of the control groove 102A of the control plate 102 of FIG.
1 and the moving knife 112 are positioned above the inner hook lower thread outlet. The position shown in FIG. 19 is the most advanced position.

In FIG. 19, L3 is the position of the thread separation 111 and the moving knife 112 at the initial position, L4 is the position of the thread separation 111 and the moving knife 112 at the most forward position, β
1 is the thread handling when moving from the initial position to the most advanced position 1
11 is a horizontal rotation angle of the moving knife 112 and the moving knife 112. At the most advanced position, the moving knife 112 moves the cutting protrusion 11 of the thread separating member 111 as the drive pin 108 moves.
Sliding away from 1E.

The drive shaft 103 is rotated in the opposite direction from the state shown in FIG. In FIG. 20, the drive shaft 103 and the protrusion 104
If the line segment connecting B is L5, the angle α2 formed by L2 and L5
Is the rotation angle of the drive shaft 103 from the most advanced position. At this time, the drive pin 108 is connected to the control groove 102 of the control plate 102.
Move from e to d of A to c.

The drive pin 108 is the control groove 1 of the control plate 102.
By moving from the position e of 02A to the position d, the thread separating member 111 and the moving knife 112 are horizontally rotated by β2 from the most advanced position to the position (cutting position) shown in FIG.
Move to. In FIG. 20, when L6 is the position of the thread separating unit 111 and the moving knife 112, the angle formed by L4 and L6 is β2.

At the beginning of this movement to the cutting position, the lower thread 115 is caught by the lower thread catching notch 111C of the thread separating 111, and then the upper thread 115 is caught by the upper thread catching notch 111D.
Is captured. After that, the drive pin 108 moves from d to e of the control groove 102A of the control plate 102, so that the moving knife 112 slides in the direction of the cutting protrusion 111E of the thread separating unit 111 and moves vertically between the cutting protrusion 111E and the cutting edge 112C. Thread 1
14 and 115 are cut. After cutting, lower thread 1 on the shuttle 120 side
14 is held between the thread separation 111 and the moving knife 112.

The drive shaft 103 is further rotated from the cutting position in FIG. 20 to return to the initial position as shown in FIG. During this return movement, the bobbin thread 114 held between the thread separation 111 and the moving knife 112 is fed out from the shuttle.

As described above, in the present embodiment, both the first member (thread separating member 111) and the second member (moving knife 112) can be horizontally rotated so that the first member and the second member can be rotated.
However, the first and second members are different from each other in that they can be slid in the horizontal direction and the linear direction instead of being opened and closed.

In the third embodiment, the drive shaft 10
Driving of No. 3 is performed after the operation of the sewing machine is stopped, and can be made equivalent to the timing chart of the first embodiment described in FIG. Further, as described above, when the fixing position of the control plate 102 and the base 101 is changed by the screw 131, the relative position of the control plate 102 and the drive pin 108 is changed.
The operating position (cutting position, standby position) of the member and the second member changes. Therefore, the operating position can be easily changed by the fixing position of the screw 131. According to the third embodiment, the same effects as (1) to (3) mentioned as the effects of the second embodiment can be obtained. The present invention is not limited to the above-described embodiment. For example, in the second and third embodiments, the cam is used to rotate the first member and the second member and to perform the opening / closing operation in the horizontal direction or the linear direction. However, instead of this, it is easily conceivable to make the first member and the second member perform the same operation by using an independently driven actuator or the like. Also,
The present invention includes a moving position (initial position, most advanced position, cutting position,
The upper and lower thread lengths are determined by the standby position). The length of thread remaining on the sewing product and the length of needle thread remaining on the needle side depend on the cutting position.
When moving to the power standby position for cutting, both determine the remaining length on the bobbin hook side. Each moving position can be easily changed. That is, by controlling the rotation of the first and second solenoids, which are the drive means in the first embodiment, the cam attachment position, which is the drive means in the second and third embodiments, can be changed, and the cam can be changed. By exchanging with a different shape. As described above, each of the above embodiments also has a unique effect that the upper and lower threads can be freely changed to a predetermined length after being cut.

[0080]

In the thread cutting device for a sewing machine according to the present invention, the movable member which is movable in the horizontal direction above the shuttle comprises the first member having the thread catching portion and the second member having the blade.
The upper and lower threads can be cut above the shuttle and near the needle drop point. Therefore, it is possible to shorten the length of the thread piece remaining on the sewing object after thread cutting.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a thread cutting device for a sewing machine according to the present invention.

2 shows a first embodiment, (a) is XX of FIG.
Sectional drawing, (b) is sectional drawing which showed only the cutting blade at the time of opening.

FIG. 3 shows the first embodiment, (a) is a perspective view of a thread cutting fixed blade, and (b) is a perspective view of a cutting lever.

FIG. 4 shows the first embodiment, (a) is a perspective view of a thread cutting fixed blade, and (b) is a perspective view of a cutting lever.

5A and 5B show a first embodiment, FIG. 5A is a perspective view of a thread cutting device, and FIG. 5B is a perspective view of a cutting lever.

FIG. 6 is a timing chart showing the operation curves of the picker base and the like associated with the rotation of the picker base mount of the first embodiment, together with the movement curves of the needle bar, the balance and the shuttle of the sewing machine.

FIG. 7: The picker base of the first embodiment is initial (standby)
It is a top view of the state in the position A.

FIG. 8: The picker base of the first embodiment is at the most advanced position B
It is a top view of the state which moved to.

FIG. 9 is a top view showing a state where the picker base of the first embodiment moves to the cutting position C and cuts the yarn.

FIG. 10 is a top view showing a state where the picker base has returned to the initial position A after the thread is cut in the first embodiment.

FIG. 11 is an exploded perspective view of a yarn cutting device according to a second embodiment.

12A and 12B show a second embodiment, FIG. 12A is a top view of a state in which the thread separation is in an initial (standby) position, and FIG.
FIG.

13A and 13B show a second embodiment, FIG. 13A is a top view of a state in which the yarn handling is moved to the most advanced position, and FIG. 13B is a sectional view taken along line BB of FIG. 13A.

14A and 14B show a second embodiment, in which FIG. 14A is a top view showing a state in which the thread separation is moved to the thread cutting position, FIG. 14B is a sectional view taken along line CC of FIG. 14A, and FIG. ) Is a partially enlarged view of FIG.

FIG. 15 is an enlarged view showing the tip of the thread separating blade and the moving knife immediately after cutting in the second embodiment, (a) being a perspective view;
(B) is the perspective view seen from the D direction of (a), (c) is sectional drawing.

FIG. 16 is an exploded perspective view of a yarn cutting device according to a third embodiment.

FIG. 17 shows a control plate of a third embodiment, (a) is a perspective view and (b) is a front view.

FIG. 18 is a top view showing a state in which the thread separating device and the moving knife of the third embodiment are in the initial (standby) position A.

FIG. 19 is a top view showing a state in which the thread separating and moving knife of the third embodiment have moved to the most advanced position B.

FIG. 20 is a top view showing a state in which the thread separating device and the moving knife of the third embodiment have moved to the cutting position.

FIG. 21 is a top view showing a state in which the thread separating device and the moving knife of the third embodiment have returned to the initial position A.

22 is a partially enlarged perspective view of FIG. 20. FIG.

FIG. 23 is a top view of an example of a conventional upper and lower thread cutting device of a sewing machine.

FIG. 24 is a top view of another example of a conventional upper and lower thread cutting device of a sewing machine.

FIG. 25 is a perspective view of a conventional yarn cutting device of the type shown in FIG. 24.

FIG. 26 is a perspective view showing the manner in which the yarn is cut by the device of FIG. 25.

FIG. 27 is a perspective view showing a sewn product after thread cutting.

[Explanation of symbols]

2 Fixed blade for bobbin thread cutting 4 Cutting lever (first member) 8 Picker base (second member) 12
Protrusion 10 Fixed blade for needle thread cutting 18 Swing shaft 24 Lower thread catching protrusion 26 Upper thread catching protrusion 2
8,30 Cutting blade 32 Lower thread clamp spring 34 Hook 3
6 Lower thread 38 Upper thread 46 Needle drop point 5
8 Moving knife guide pin 60 Thread separation (first member) 6
0A, 68A Long groove 60B Recess 60C Blade surface 6
0D Protrusion 60E Recess 66 66 Moving knife shaft 6
8 Moving knife (2nd member) 68B Blade portion 70 Lower thread clamp spring 7
2 Lower presser pin 74 Lower presser foot 78 Needle drop 8
4 Lower thread 86 Upper thread 102 Control plate 1
02A Control groove 111 Thread separation (first member) 1
11C Lower thread catching notch 111D Upper thread catching notch 1
11E Cutting Protrusion 112 Moving Knife (Second Member) 1
12C Cutting blade 114 Upper thread 114,115 Upper and lower thread 1
15 bobbin thread

Claims (7)

[Claims] 1. A sewing machine characterized in that a first member having a thread catching portion and a second member having a blade are provided, and both the first and second members are movable in the horizontal direction above the shuttle. Thread cutting device. 2. The thread cutting device for a sewing machine according to claim 1, wherein the upper and lower threads are caught by the thread catching portion of the first member, and the first and second members are moved to a position above the shuttle to remove the upper and lower threads. A thread cutting device for a sewing machine, which is characterized by cutting. 3. The thread cutting device for a sewing machine according to claim 1, wherein the thread catching portion of the first member catches a bobbin thread cutting end, and the bobbin thread cutting end is released at the start of sewing. Sewing machine thread cutting device. 4. The thread cutting device for a sewing machine according to claim 1, wherein the first member and the second member can be opened and closed in the vertical direction, and when the first member and the second member are closed, the upper and lower yarns are threaded between the first and second members. A thread cutting device for a sewing machine, which is characterized by cutting. 5. The thread cutting device for a sewing machine according to claim 1, wherein the first member and the second member can be opened and closed in a horizontal direction, and when the first member and the second member are closed, upper and lower yarns are laid between the first member and the second member. A thread cutting device for a sewing machine, which is characterized by cutting. 6. The thread cutting device for a sewing machine according to claim 1, wherein the first member and the second member are linearly movable in a horizontal direction, and upper and lower threads are cut between the first member and the second member. A thread cutting device for a sewing machine. 7. The sewing machine according to claim 1, wherein the upper thread catches the upper and lower threads before the upper thread crosses the shuttle, and the shuttle rotates to remove the upper thread from the shuttle. A thread cutting device for a sewing machine, which captures and cuts a lower thread.