JP2884841B2 - sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine provided with a thread holding means for catching and holding an end of an upper thread cut by a thread cutting device.

[0002]

2. Description of the Related Art In this type of sewing machine, at the end of sewing, the end of an upper thread cut by a thread cutter is caught and grasped by thread grasping means, and the end of the upper thread is released when sewing starts. As a result, the length of the thread foot at the start of sewing can be shortened. This eliminates the need for thread picking work after sewing and prevents the occurrence of irregular entanglement of the thread (so-called bird's nest-like thread entanglement). The thread gripping means is provided with a thread gripping member for capturing an end of the upper thread rotatably, a thread presser spring rotatably provided, and the thread gripping member and the thread presser spring are appropriately rotated by a solenoid or the like. By doing so, the end of the upper thread captured by the thread gripping member is sandwiched between the thread gripping member and the thread pressing spring.

[0003]

In the above-mentioned conventional construction, at the end of sewing, a thread cutting device is operated to cut the upper thread, and subsequently, the thread holding means is automatically operated to cut the upper thread. The end of is captured and gripped. In this case, the gripping operation of the upper thread by the thread gripper may fail for some reason. In such a case, before the start of sewing, the end of the upper thread that has failed to be gripped is gripped by the operator's finger, and the upper thread is gripped in a state where the upper thread has been fed out by a certain amount of thread. To start sewing.

However, when sewing is performed as described above,
At the start of sewing, it is necessary to pinch and hold the end of the upper thread with fingers, and a thread pinching operation must be performed after sewing, which makes the sewing operation considerably troublesome. However, in order to stop grasping the end of the upper thread by hand with fingers, the thread grasping means must grasp the end of the upper thread.

In this case, since the solenoid cannot be energized to cause the thread gripping means which has failed to grip the end of the upper thread, the thread gripping member and the thread presser spring are appropriately rotated by manual operation. By doing so, the end of the upper thread is sandwiched between the thread gripping member and the thread presser spring.
However, there is a problem that the operation of rotating the thread gripping member and the thread presser spring by manual operation is very troublesome.

Accordingly, an object of the present invention is to make it possible to easily operate the thread grasping means again when the grasping operation of the upper thread by the thread grasping means fails, thereby causing the thread grasping means to easily grasp the end of the upper thread. Another object of the present invention is to provide a sewing machine capable of improving sewing workability. Another object of the present invention is to
An object of the present invention is to provide a sewing machine capable of preventing the thread gripping means from being damaged by colliding with a sewing needle or a cloth presser when the thread gripping means is operated again.

[0007]

SUMMARY OF THE INVENTION A sewing machine according to the present invention is provided so as to be manually operable in a sewing machine provided with a thread holding means for catching and holding an end of an upper thread cut by a thread cutting device. It is characterized in that it has an operation switch and a control means for operating the thread gripping means based on the operation of the operation switch.

In this case, the control means may be configured to have a safety function for restricting the operation of the thread gripping means when the stop position of the sewing needle is not at the upper position or when the cloth presser is not at the presser position. .

[0009]

After the upper thread has been cut by the thread cutting device, the thread gripping means is automatically operated to capture and grip the cut end of the upper thread. Gripping operation may fail. In such a case, according to the above means, the yarn gripping means can be operated again only by manually operating the operation switch, whereby the yarn gripping means can easily grip the end of the upper thread. Then, at the start of sewing, the work of pinching the end of the upper thread with fingers and the like becomes unnecessary, so that sewing workability is improved.

When the yarn gripping means is operated again,
When the stop position of the sewing needle is not at the upper position or when the presser foot is not at the presser position, the thread grasping means is regulated so as not to be operated, so that the thread grasping means may be damaged by colliding with the sewing needle or the presser foot. It can be reliably prevented.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. First, in FIG. 2 and FIG. 3, a needle bar 2 is provided in a sewing machine head 1 provided on the left end side of a sewing machine arm portion constituting the sewing machine main body so as to be vertically movable. The lower end of the needle bar 2 projects downward from the lower portion of the sewing machine head 1, and a sewing needle 3 is attached to the lower end of the needle bar 2. The needle bar 2 is configured to be vertically reciprocated by a sewing machine motor (not shown) via a main shaft and a crank mechanism (both not shown).

Behind the needle bar 2, the presser bar 4 is
Are provided so as to be able to move up and down in a state where they are arranged substantially in parallel with each other. The presser foot 5 is attached to the lower end of the presser bar 4. The cloth presser bar 4 is urged downward by a presser spring (not shown), and is manually operated by a presser lifting lever (not shown) rotatably provided on the rear surface of the sewing machine head 1. To be moved to The presser bar 4 is configured to be moved upward by electrically driving a presser lifting solenoid (not shown), which is a presser driving means, for example.

A thread holding device 6 serving as a thread holding means is provided on the sewing machine head 1 so as to correspond to the sewing needle 3. The thread gripping device 6 captures and grips the cut end of the upper thread 7 guided from a thread supply source via a balance (both not shown) and passed through the eye of the sewing needle 3. I have. Hereinafter, the yarn gripping device 6 will be described.

In the yarn holding device 6, the yarn holding lever 8
As shown in FIG. 5, the first arm 8a and the first arm 8a
And a second arm 8b that forms a predetermined angle with respect to the arm 8a, and is rotatably provided around the shaft 9 as a fulcrum. A link member 1 is provided at the right end of the first arm 8a.
0 is connected, and the thread gripping lever 8 is rotationally driven by a solenoid (not shown) via the link member 10. A thread gripping member 11 is attached to the right end of the second arm 8b.
Is provided with a yarn gripping portion 11a at the tip end.

A thread presser lever 12 is provided so as to be rotatable around the shaft 9 as a fulcrum. A link member 13 is connected to the right end of the thread presser lever 12, and the thread presser lever 12 is driven to rotate by a solenoid (not shown) via the link member 13. A torsion coil spring 14 is provided between the thread holding lever 12 and the thread gripping lever 8. The torsion coil spring 14 urges the thread holding lever 12 clockwise with respect to the thread gripping lever 8.

Further, a thread presser arm member 14 is provided so as to rotate integrally with the thread presser lever 12, and a thread presser spring 15 is attached to the right end of the thread presser arm member 14. A thread presser 15a is attached to the tip of the thread presser spring 15.
The thread presser 15a and the thread gripping member 1 are provided.
The end of the upper thread 7 is sandwiched between the first thread grip 11a. In addition, the thread holding device 6
4, the thread gripping member 11 and the thread presser spring 15 are turned to the retracted position and stopped at that position, as shown in FIG.

A needle plate is provided below the sewing machine head 1, and a thread cutter having an upper knife and a lower knife (not shown) is provided below the needle plate. . This thread cutting device is configured to cut the upper thread 7 and the lower thread (not shown) by swinging the upper knife and the lower knife. Below the needle plate, for example, a hook, which is a thread catcher, is provided so as to operate in synchronization with the sewing needle 3.

On the other hand, an operation panel 16 shown in FIG. 6 is provided on a front surface of a portion extending laterally of the sewing machine arm. The operation panel 16 includes a selection switch 17 for selecting an operation mode, an operation switch 18 having both a function of moving the thread gripping device 6 from the gripping position to the retreat position and a function of manually operating the thread gripping device 6, and a reverse stitch. A setting unit 19 for setting whether or not to perform stitching and setting the number of stitches for stitching when performing reverse stitching, and a display unit 20 for displaying the set number of stitches and the like are provided.

In FIG. 7 showing the electrical configuration, a control circuit, for example, a control circuit 21, which is a control means, includes a microcomputer and stores a control program for controlling the overall sewing operation of the sewing machine. I have. The control circuit 21 includes a hand position detecting means 22, a pedal switch 23,
Each signal from the input switch circuit 24 and the presser foot position detecting means 25 is received. The needle position detecting means 22 includes a disk provided on the main shaft, a photo interrupter (both not shown), and the like.
Outputs a needle up signal when is in the upper position, and outputs a needle down signal when the sewing needle 3 is in the lower position.

The pedal switch 23 is configured to be operable to a front depressed position, a neutral position, and a rear depressed position by an operator's depressing operation. The pedal switch 23 outputs a sewing machine start signal when operated to the front depressed position, a sewing machine stop instruction signal when operated to the neutral position, and a thread trimming operation signal when operated to the rear depressed position. Has become. The input switch circuit 24 has various switches provided on the operation panel 16, and outputs various signals when the various switches are operated.
The presser foot position detecting means 25 is composed of a photo interrupter or the like, outputs a presser position detection signal when the presser foot 5 is at the presser position, and outputs an upper position detection signal when the presser foot 5 is moved upward. Output.

The control circuit 21 supplies control signals to a sewing machine motor drive circuit 26, a brake drive circuit 27, a thread gripping device drive circuit 28 and a cloth presser drive circuit 29, respectively. The sewing machine motor drive circuit 26
When the control signal is given to the sewing machine, the sewing machine motor is energized and driven. When a control signal is supplied to the brake drive circuit 27, the sewing machine motor is turned off, and an electromagnetic brake provided in the sewing machine motor is operated to brake and stop the sewing machine motor.

When a control signal is supplied to the thread gripping device drive circuit 28, a solenoid for driving the thread gripping lever 8 and a solenoid for driving the thread presser lever 12 are appropriately energized, and the thread gripping device 6 is turned on. Activated. When a control signal is supplied to the presser foot drive circuit 29, the presser foot lifting solenoid is energized, and the presser foot bar 4 and the presser foot 5 are automatically moved upward.

Next, the operation of the above configuration will be described with reference to FIG. FIG. 1 is a flowchart schematically showing the contents of a portion of the control program stored in the control circuit 21 for controlling the drive of the thread gripping device 6. First, when the pedal switch 23 is depressed to the rear depressed position via the neutral position during the execution of the normal sewing operation, the thread cutting device is operated to cut the upper thread 7 and the lower thread. Subsequently, the thread gripping device 6 is automatically operated, and the cut end of the upper thread 7 is captured and gripped. At this time, the thread gripping device 6
May fail to grip the upper thread 7. In this case, the thread holding member 11 of the thread holding device 6 and the thread holding spring 15
Is located at the gripping position as shown by the solid line in FIG.
In this state, in the case where the operation switch 18 of the operation panel 16 is manually operated and the thread gripping device 6 is operated again,
It is described according to FIG.

When the operation switch 18 is operated by the operator in the above state, that is, the state in which the thread gripping device 6 is in the gripping position (ie, by the first operation of the operation switch 18),
Go to "YES" in step S1. Subsequently, since the sewing machine is in the stopped state after the thread trimming operation is performed, the process proceeds to "YES" in step S2, and the thread gripping device 6 is moved from the gripping position to the retracted position shown in FIG. 4 (step S3). S
4, S5). Specifically, a thread gripper operating signal is given to the thread gripper drive circuit 28, and the solenoid driving the thread gripping lever 8 and the solenoid driving the thread presser lever 12 are appropriately energized and driven.

As a result, the thread grasping lever 8 and the thread presser lever 12 are rotated counterclockwise in FIG. 4, and the thread grasping member 11 and the thread presser spring 15 swing in response to the rotation to the retracted position. To move. Thereafter, a time of, for example, 0.1 second, which is the set time ΔT, is measured.

After the elapse of 0.1 second, that is, with the thread gripping device 6 at the retracted position, the operation switch 1
When 8 is operated again (that is, by the second operation of the operation switch 18), the process proceeds to “NO” in step S1 and proceeds to “YES” in step S6. Subsequently, it is determined whether or not the presser foot 5 is located at the presser position based on the detection signal from the presser foot position detection means 25 (step S7). Here, when it is detected that the cloth presser 5 is located at the presser position, the process proceeds to "YES" in step S7, and it is determined whether the sewing needle 3 is at the upper position (step S7). S8). Here, when it is detected that the sewing needle 3 is located at the upper position, "YE" is determined in step S8.
S ", the yarn gripping device 6 is moved from the retracted position shown in FIG. 4 to the gripping position shown in FIG. 3, and the yarn gripping device 6 is actuated to capture and grip the end of the upper thread 7 (step). S9, S10, S11).

More specifically, a thread gripper operating signal is supplied to the thread gripper drive circuit 28, and the solenoid for driving the thread gripper lever 8 and the solenoid for driving the thread presser lever 12 are appropriately energized and driven. Thereby, the thread gripping lever 8 and the thread presser lever 12 are rotated clockwise in FIG. 4, and the thread gripping member 11 and the thread presser spring 15 swing in response to the rotation, so that the thread retracting position is moved from the retracted position to the gripping position ( (See FIG. 3). When the thread gripping lever 8 is further rotated clockwise in FIG. 3 at this gripping position, the thread gripping member 11 swings as indicated by a two-dot chain line in accordance with the rotation. The thread gripping portion 11a hooks and catches the end of the upper thread 7. Thereafter, when the thread gripping member 11 returns to the original position,
The end of the captured upper thread 7 is the thread gripper 11 of the thread gripper 11.
a and the thread presser 15a of the thread presser spring 15. In this state, the set time ΔT, for example, 0.1 seconds is measured.

When sewing is started while the end of the upper thread 7 is gripped by the thread gripping device 6, the thread gripping lever 8 and the thread presser lever 12 are moved counterclockwise as shown in FIG. Rotate. At this time, the differential is made so that the rotation angle of the thread holding lever 12 is larger than the rotation angle of the thread gripping lever 8. Thereby, the yarn gripping portion 11 of the yarn gripping member 11
The end of the upper thread 7 held between the thread a and the thread presser 15a of the thread presser spring 15 is released. During the execution of the sewing, the thread gripping lever 8 and the thread presser lever 12 rotate to the retracted position shown in FIG. 4 and are held at that position.

On the other hand, if it is detected in step S7 that the cloth presser 5 is not located at the presser position, the process proceeds to "NO" in step S7, and the thread gripping device 6 remains at the retracted position. Does not work. If it is detected in step S8 that the sewing needle 3 is not located at the upper position, the process proceeds to "NO" in step S8, and the thread gripping device 6 does not operate while remaining at the retracted position.

According to the present embodiment having such a configuration, even if the gripping operation of the upper thread 7 by the thread gripping device 6 fails for some reason, the operation switch 18 of the operation panel 16 is manually operated. By operating the yarn gripping device 6 again, the end of the upper thread 7 can be captured and gripped. For this reason,
Unlike the conventional configuration, it is not necessary to perform the operation of picking up and holding the end of the upper thread 7 with fingers at the start of sewing, so that the sewing workability can be improved.

In the above embodiment, when the thread gripping device 6 is operated again, when the stop position of the sewing needle 3 is not at the upper position or when the cloth presser 5 is not at the pressing position, the thread gripping device 6 is moved to the retracted position. Since it is configured so as not to be operated while being kept in the position, the thread gripping member 11 of the thread gripping device 6 can be reliably prevented from colliding with the sewing needle 3 and the cloth presser 5 and being damaged.

In the above embodiment, by disposing the thread grasping device 6, the upper thread 7 is cut by the thread grasping device 6 before the start of sewing, that is, when the thread trimming device is cut at the end of sewing. The end of the upper thread 7 is released at the start of sewing, so that the length of the thread foot at the start of sewing can be shortened, eliminating the need for thread picking work. it can.

[0033]

Since the present invention is as described above, the following effects can be obtained.

In the sewing machine according to the first aspect, the operation switch is manually operated to operate the thread gripping means to catch and grip the cut end of the upper thread. Even if the gripping operation of the upper thread by the gripping means fails, the yarn gripping means can easily grip the end of the upper thread simply by manually operating the operation switch. Then, in this case, it is not necessary to pinch and hold the end of the upper thread with fingers at the start of sewing, and thus the sewing workability is improved.

In the sewing machine according to the second aspect, when the thread gripping means is operated again, when the stop position of the sewing needle is not at the upper position or when the cloth presser is not at the presser position, the thread gripping means is not operated. With this configuration, it is possible to reliably prevent the thread gripping means from being broken by colliding with the sewing needle or the presser foot.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention.

FIG. 2 is a side view around the yarn gripping device.

FIG. 3 is a front view around the yarn gripping device.

FIG. 4 is a front view showing a state where the yarn gripping device is located at a retracted position.

FIG. 5 is a front view showing a state in which the thread gripping device is releasing the upper thread.

FIG. 6 is a front view of an operation panel.

FIG. 7 is a block diagram.

[Explanation of symbols]

2 is a needle bar, 3 is a sewing needle, 5 is a cloth presser, 6 is a thread holding device, 7
Denotes an upper thread, 11 denotes a thread gripping member, 15 denotes a thread presser spring, 16 denotes an operation panel, 18 denotes an operation switch, and 21 denotes a control circuit (control means).

Claims (2)

(57) [Claims] 1. A sewing machine comprising a thread holding means for catching and holding an end of an upper thread cut by a thread cutting device, comprising: an operation switch provided to be manually operable; And a control means for operating the thread gripping means based on the sewing machine. 2. The control device according to claim 1, wherein the control means has a safety function of restricting the operation of the thread gripping means when the stop position of the sewing needle is not at the upper position or the presser is not at the presser position. The described sewing machine.