JP3530605B2 - Thread trimming device in thread trimming sewing machine - Google Patents

Description

Detailed Description of the Invention

[0001]

Yarn of the present invention is a thread cutting sewing machine BACKGROUND OF THE INVENTION
Regarding the cutting device.

[0002]

2. Description of the Related Art FIG. 1 shows a thread trimming device for a thread trimming sewing machine.
The ones shown in FIGS. 1 to 13 are known. 11 is a top view, FIG. 12 is a perspective view, and FIG. 13 is a partially enlarged perspective view.

In the drawing, reference numeral 214 denotes a shuttle,
A fixed knife 216 fixed to the shuttle support and a moving knife 212 that can reciprocate in the direction of the arrow in the figure are provided above the table. A bobbin thread clamp spring 220 is attached to the fixed knife 216.

The moving knife 212 moves from the position shown in the direction away from the fixed knife 216, catches the bobbin thread 206 coming out of the shuttle 214, and returns to the position shown in the drawing to cut it. The lower thread 206 is held by the lower thread clamp spring 220 immediately before cutting.

At the beginning of the next sewing, it is necessary to secure a predetermined length of the bobbin thread on the hook 214 side so that the thread may be entangled and a seam may be easily formed. Before entering, when the moving knife 212 returns, the lower thread 206 is
It is drawn from 4.

[0006]

However, in the above-mentioned conventional thread cutting device, since the cutting edge of the fixed knife 216 is separated from the needle drop P of the needle plate 228 of the sewing machine, as shown in FIG. The yarn piece 206A remaining on the back side of the yarn becomes long. If, for example, the position of the fixed knife 216 is moved closer to the needle drop point in order to shorten the thread piece 206A, it is difficult because the upper and lower threads hinder the movement for knotting the stitches, but this is possible. However, as shown in FIG. 15, the length of the thread 206B from the hook toward the cutting point, that is, the vicinity of the needle drop is shortened, so that it is difficult to get entangled with the upper thread at the next sewing start after the thread cutting is finished, Are less likely to be formed.

The lower thread 206 is a lower thread clamp spring 22.
Since it is cut immediately after it is held at 0, the end of the cut thread deviates from the pressing surface of the lower thread clamp spring 220, the amount of the thread end held by the catching position decreases, and so on. May become unstable.

Therefore, an object of the present invention is to provide a thread trimming sewing machine capable of shortening the length of the thread piece 206A remaining on the back side of the cloth after thread trimming and at the same time ensuring the length of the thread side 206B from the hook to the cutting point. It is to provide a thread cutting device.

Another object of the present invention is to provide a thread trimming device for a thread trimming sewing machine capable of preventing troubles such as defective clamping and reliably holding a lower thread.

[0010]

According to the present invention in order to achieve the above object, there is provided a means for solving], the first member having a thread catching portion, wherein
A second member that is openably and closably connected to the first member and that has a blade portion; a drive unit that imparts a rotational movement to either the first member or the second member; and one end of the sewing machine frame. Connecting means that is pivotally supported and that opens and closes the first member and the second member by the action of the driving means, and the lower thread is fed to the second member and the thread is positioned at a predetermined position when the thread is cut.
And a locking member for holding, in a thread cutting operation, before
The locking member is lowered until the second member returns to the standby position.
Threads in thread-cutting sewing machines characterized by holding threads
A cutting device is provided.

Preferably, the locking member has a catching section for catching the lower thread, a holding section for holding the thread at a predetermined position when cutting the thread, and a ridge line formed between the catching section and the holding section. The lower thread caught by the catching section is moved along the ridgeline and held by the holding section.

[0012]

By the driving means, a rotational movement is imparted to either the first member having the yarn catching portion or the second member having the blade portion which is openably and closably connected to the first member. It The first member and the second member act by the action of the rotational movement.
Ri is open or closed. This closure cuts the thread. The lower thread is fed to the second member and the thread is cut at the time of thread cutting.
Is provided with a locking member for holding the in position .

With such a construction, the bobbin thread from the bobbin thread outlet of the shuttle can be cut at a position close to the needle drop point, so that the length of the thread piece remaining on the back side of the cloth after thread cutting is shortened. can do. Also, the locking member holds the thread even after thread cutting.
By holding it, the bobbin thread length required to start sewing after cutting
To secure the length (the length of the bobbin thread from the hook to the cutting point)
it can.

Furthermore, by providing the catching portion, the holding portion and the ridge line on the locking member, the bobbin thread caught by the yarn catching portion can be moved along the ridge line and held by the holding portion. Since the bobbin thread is fed out from the bobbin thread outlet in the process of this movement, the bobbin thread length (the length of the bobbin thread from the shuttle to the cutting point) necessary for starting sewing after cutting can be secured.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a thread trimming sewing machine according to the present invention.
FIG. 2 is a top view of an embodiment of the thread cutting device, FIG. 2 is a perspective view of the thread separating and moving knife base of the embodiment of FIG. 1, and FIG. 3 is a partially exploded perspective view of the embodiment of FIG.

In these drawings, reference numeral 2 is a thread separating member (first member) arranged on the shuttle 4, and is fixed to the thread separating base 3. The yarn handling base 3 is fixed to the upper end of a swingable drive shaft 6. Therefore, the yarn handling unit 2 is swingably rotatable by swinging the drive shaft (driving means) 6.

A moving knife base 8 is attached to the lower side of the thread separating unit 2 so as to be swingable around a fulcrum shaft 10 connected to the thread separating unit 2 (first member). A moving knife 12 (second member) and a bobbin thread picker 14 are fixed to the tip of the moving knife base 8.
A groove 15 is formed near the opposite end. In addition,
A cutting blade that cooperates with the moving knife 12 to cut the yarn is formed at the tip of the yarn handling device 2.

The lower thread picker 14 (locking member) is provided with a hook-shaped portion 14A (capturing portion) at its tip and a notch portion 14B (holding portion) near the moving knife base 8. A ridge line 14C between the hook-shaped portion 14A and the notch portion 14B has a shape capable of feeding the lower thread as described later.

Reference numeral 16 denotes a support arm which is attached so as to be rotatable around an arm shaft 18, and a pin 20 which fits into the groove 15 is attached to the tip of the support arm 16. When the support arm 16 rotates, the pin 20 and the groove 15 open and close the thread separating device 2 and the moving knife base 8. The support arm 16, the arm shaft 18, and the pin 20
The groove 15 constitutes a connecting means. A support base 19 supports the arm shaft 18 of the support arm 16 and the drive shaft 6 swingably.

The lower thread 22 held by the thread cutting device of this embodiment extends from the lower thread outlet 5 of the shuttle 4 toward the needle drop point 7. 4 to 7 are top views showing the operation of the thread trimming device of this embodiment. FIG. 4 is a standby position, FIG. 5 is an opening / closing start position, FIG. 6 is a lower thread catching position, and FIG. It is a figure which shows the thread separation 2 and the moving knife base 8 of FIG. FIG. 8 (A) shows the lower thread picker 14 and the moving knife 12 of the moving knife base 8 at the capture position.
FIG. 8B is a perspective view showing the line XX of FIG. 8A.
FIG.

When the thread cutting operation of the sewing machine starts, the thread separation 2
The moving knife base 8 rotates counterclockwise from the standby position in FIG. Up to the opening / closing start position in FIG.
And move in a closed state, and the tip of the lower thread picker 14 passes above the shuttle 4 and below the lower thread 22.

From the opening / closing start position shown in FIG. 5, the thread separating device 2 and the moving knife base 8 start to open due to the action of the drive shaft 6, the support arm 16, the pin 20, and the groove 15.

At the catching position in FIG. 6, the hook portion 1 at the tip of the lower thread picker 14 is rotated by the counterclockwise rotation of the moving knife base 8.
The bobbin thread 22 enters 4A, and until the most advanced position of FIG.
As shown by an arrow A in FIG. 8 (A), a portion (bent portion) 22A that contacts the lower thread picker 14 of the lower thread 22 is the lower thread picker 1.
It moves to the notch 14B along the ridgeline 14C of No. 4 and is held by the notch 14B. During this period, the bobbin thread exit 5
A ridge line 14C from the hook-shaped portion 14A to the notch portion 14B of the lower thread picker 14 is formed so that the lower thread 22 is fed out from the lower thread picker 14. The ridge line 14C is formed by a continuous curve so that the lower thread can move smoothly during the operation of the lower thread picker 14.

In this way, the notch portion 14B returns to the standby position in FIG. 4 while holding the lower thread 22, but the position in FIG. 5, which was the opening / closing start position in the forward movement, becomes the cutting position in the backward movement. At this cutting position, the thread separating member 2 and the moving knife base 8 are closed, and a thread cutting operation is performed between the moving knife 12 and the tip of the thread separating member 2. At this cutting position, the distance between the needle drop point 7 and the cutting portion is minimized, so that the length of the thread piece remaining on the back side of the cloth after thread cutting can be shortened.

The bobbin thread 22 moves to the notch portion 14B during the forward movement to the most advanced position in FIG.
Since the bobbin thread 22 is cut after returning to the cutting position shown in FIG. 5 after being held by, the end of the thread after cutting is different from the conventional method in which the bobbin thread 22 is held immediately before cutting. The bobbin thread will not become unstable due to, for example, being disengaged from the holding portion or the amount of held thread ends being reduced.

While the bobbin thread 22 is cut at the cutting position shown in FIG. 5, the notch portion 14B holding the cut end of the bobbin thread 22 moves away from the bobbin thread outlet 5 while returning to the standby position shown in FIG. Therefore, the end of the held bobbin thread 22 is pulled toward the bobbin thread exit 5 side and moves while sliding the bobbin thread picker 14. Therefore, the length of the end of the lower thread 22 being held becomes shorter. However, in the present embodiment, as described above, the lower thread outlet 5 is provided between the standby position of FIG. 4 and the most advanced position of FIG.
The bobbin thread 22 is being fed from the. Therefore, by determining the shape of the bobbin thread picker 14 so that the amount to be paid out at this time is appropriate, the bobbin thread length required to start sewing (from the hook to the cutting point) even after returning to the standby position in FIG. The length of the lower thread) can be secured.

FIG. 9 shows a thread trimming sewing machine according to the present invention.
It is a partial top view of other examples of a thread trimming device. In this embodiment, the bobbin thread clamp spring 30 is provided near the tip of the moving knife base 8, but other points are the same as the embodiment shown in FIG. The lower thread clamp spring 30 is used for the lower thread picker 14
Is arranged above the notch portion 14B.

In the case of this embodiment, after the lower thread is captured, the lower thread 22
Immediately before entering into the notch portion 14B, the lower thread 22 is securely held by the pressing of the lower thread clamp spring 30 because it enters the gap between the lower thread picker 14 and the lower thread clamp spring 30. The lower thread clamp spring 30 is provided with a hook-shaped portion 1 before the lower thread 22 enters the notch portion 14B after being caught by the hook-shaped portion 14A.
The lower thread 22 may be pressed and held while moving the ridge line 14C between the 4A and the notch portion 14B.

In the thread trimming device of each of the above embodiments, as shown in the accompanying drawings, the present embodiment is applied to a sewing machine having a horizontal hook in which the hook is horizontally arranged. Not limited to this, the present invention can be applied to a sewing machine having a vertical shuttle in which the shuttle is arranged vertically. Although the lower thread picker 14 has a plate-like shape, the lower thread 2 is
It is only necessary that 2 can be moved as in the embodiment.

FIG. 10 shows an example in which a thread cutting device using a lower thread picker 24 made of a wire is applied to a sewing machine having a vertical shuttle 23. This lower thread picker 24 has a hook-shaped portion 2 at the tip.
The lower thread 22 is captured by 4A, and the lower thread 22 is moved into the notch portion 24B as the moving knife base 8 rotates. In the figure, 31 is a needle plate and T is a cutting point of the lower thread 22.

Although the thread cutting device in the thread cutting sewing machine of the present invention has been described based on the embodiment, the present invention is not limited to this embodiment and can be variously modified. For example, in the first embodiment described above, the lower thread picker 14 itself is made to have elasticity, and the lower thread 2 is provided between the lower thread picker 14 and the lower surface of the moving knife 12.
By clamping 2 the same effect as in the second embodiment can be obtained.

Further, in the present embodiment, the yarn separating device 2 (first member) is provided with a rotational movement, and the yarn separating device 2 (first member) and the moving knife base 8 (second member) are connected through the connecting means. Is open,
Close.

Instead of this, a groove shape is used that imparts a rotary motion to the moving knife base 8 (second member) and opens and closes the thread separating member 2 (first member) at a predetermined position. Is easily thought of.

[0035]

The thread trimming device of the thread trimming sewing machine of the present invention holds the lower thread from the lower thread outlet of the hook by the locking member.
In addition, since the thread is cut at a position close to the needle drop point, the length of the thread piece remaining on the back side of the cloth after thread cutting can be shortened.
Together with the bobbin thread length required from the start of the next sewing (from the hook to the cutting point)
It is possible to secure the length of the lower thread .

The lower thread caught by the catching section of the lower thread picker moves along the ridge line formed between the lower thread catching section of the lower thread picker and the holding section. Since the bobbin thread is fed from the thread outlet, the bobbin thread length (the length of the bobbin thread from the shuttle to the cutting point) necessary for the start of the next sewing after cutting can be secured.

Further, in the case of the thread trimming device in the thread trimming sewing machine provided with the lower thread clamp spring according to the present invention, the lower thread is held when the lower thread is held by the holding portion or while the ridge line is being moved. Therefore, the bobbin thread holding does not become unstable due to the fact that the end of the cut thread is disengaged from the holding portion or the like, or the amount of the held thread end is reduced.

[Brief description of drawings]

FIG. 1 is a top view of an embodiment of a thread cutting device in a thread cutting sewing machine according to the present invention.

FIG. 2 is a perspective view of the thread separating and moving knife base of the embodiment of FIG.

FIG. 3 is a partially exploded perspective view of the embodiment shown in FIG.

FIG. 4 is a view for showing the operation of the thread cutting device of the present embodiment, and is a top view when the thread cutting device is at the standby position.

FIG. 5 is a view for showing the operation of the thread cutting device of the present embodiment, and is a top view when the thread cutting device is at the opening / closing start position.

FIG. 6 is a view for showing the operation of the thread cutting device of the present embodiment, and is a top view when the thread cutting device is at the lower thread catching position.

FIG. 7 is a view for showing the operation of the thread cutting device of the present embodiment, and is a top view when the thread cutting device is at the most advanced position.

8A and 8B show a lower thread picker and a moving knife of a moving knife base in a capturing position, FIG. 8A is a perspective view, and FIG. 8B is XX of FIG.
FIG.

FIG. 9 is a partial top view of another embodiment of the thread trimming device in the thread trimming sewing machine according to the present invention.

FIG. 10 is a front view of another embodiment of the thread cutting device in the thread cutting sewing machine according to the present invention.

11 is a top view of the thread Switching Operation unit of a conventional thread trimmer.

12 is a perspective view of a yarn Switching Operation unit of a conventional thread trimmer.

13 is a partially enlarged perspective view of the yarn Switching Operation unit of a conventional thread trimmer.

FIG. 14 is an explanatory diagram for explaining a problem that the thread piece remaining on the back side of the cloth becomes long.

FIG. 15 is an explanatory diagram for explaining a problem in which the length of the yarn from the shuttle toward the cutting point is shortened.

[Explanation of symbols]

2 Thread separation 3 Thread separation base 4 hook 5 bobbin thread exit 6 drive shaft 8 moving knife base 10 fulcrum shaft 12 moving knife 14 bobbin thread picker 14A hook-shaped part (bobbin thread catching part) 14B notch part (bobbin thread holding part) 14C Ridge line 15 Groove 16 Support arm 18 Arm shaft 20 pin 22 Lower thread 22A Lower thread bending section 23 Vertical hook 24 Lower thread picker 24A Hook shape section (lower thread catching section) 24B Notch section (lower thread holding section) 30 Lower thread clamp Spring

Claims (2)

(57) [Claims] 1. A first member having a yarn catching portion, a second member openably and closably connected to the first member and having a blade portion , the first member or the second member. Driving means for imparting rotational movement to either one of the members, and one end of which is pivotally supported by the machine frame ,
Own the yarn when yarn cutting with more open of the first member and the second member, feeding a connecting means for closing the lower thread to the second member
A locking member for holding the fixed position, and in the thread cutting operation, the second member returns to the standby position.
The thread cutting device in a thread cutting sewing machine, wherein the locking member holds the lower thread until 2. The thread cutting device according to claim 1, wherein the locking member includes a catching portion that catches a lower thread, a holding portion that holds the thread at a predetermined position during thread cutting, and the catching portion. and a formed ridge between the holding portion, the lower thread captured by the capturing unit, the yarn is characterized in that holding by the holding portion is moved along the ridge line switching
Thread cutting device for sewing machines .