JP3246529B2 - Thread trimming 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 thread trimming sewing machine, and more particularly to a thread trimming sewing machine provided with a means capable of pulling out a predetermined amount of sewing thread from a thread winding source at the end of a sewing process or when cutting a sewing thread during sewing. It is.

[0002]

2. Description of the Related Art As a prior art relating to the present invention, one disclosed in Japanese Patent Publication No. 47-17585 is known. In this thread trimming sewing machine, when a thread trimming instruction is input, a movable blade rotates around a shuttle device and cuts a sewing thread together with a fixed blade disposed at a position facing the movable blade. In the trimming sewing machine, a thread pulling member is disposed between the thread tension and the thread top in order to prevent the upper thread from being pulled out of the sewing needle during thread trimming. As shown in FIG. 5, the thread pulling member 4 is rotatably disposed on the sewing machine frame 1. The thread pulling member 4 is rotated when a thread trimming instruction is input, and is rotated by the upper thread from the thread spool. The upper thread T is hooked between the two-hole thread hook 3 and the thread tension 2, and the upper thread T is fed out to a state shown by a dotted line. At this time, the tension on the upper thread T of the thread tension 2 is released, and the upper thread T after thread trimming is pulled by the tension of the thread tension 2 so as not to be pulled out from the sewing needle. Thereafter, the thread pulling member 4 returns to the original position again, but since the upper thread T is relaxed by the amount fed from the thread top (not shown), the upper thread is fed to the sewing machine needle at the time of thread trimming, and the sewing thread is released. It does not come off from the sewing needle.

[0003]

However, in this thread trimming sewing machine, the upper thread is slackened between the thread tension 2 and the three-hole thread hook 3, and the thread tension 2 is not threaded when the thread is trimmed. Since the tension to the upper thread is released, there is no means to adjust the tension of the upper thread at the time of thread trimming, and the remaining length of the upper thread after thread trimming varies depending on the type of thread. Was.

Accordingly, it is a technical object of the present invention to prevent the upper thread from coming off the sewing machine needle after thread trimming and to make the length of the upper thread remaining from the sewing machine needle constant.

[0005]

Configuration of the Invention

[0006]

According to the present invention, there is provided a technical solution to solve the above-mentioned problem. The technical solution includes a capturing portion which rotates from a standby position to an operating position to capture the sewing thread, and the capturing portion captures the sewing thread. Thread trimming means having a blade portion for cutting the sewing thread, and an auxiliary thread tensioner which is provided on the sewing machine frame and applies tension necessary for thread trimming to the upper thread unwound from the bobbin,
A thread tension on which the upper thread passing through the auxiliary thread tension is applied to apply a predetermined tension to the upper thread together with the auxiliary thread tension, and a slack of the upper thread provided in close proximity to the thread tension during a sewing cycle A thread take-up spring, tension release means for releasing the tension applied to the upper thread by the thread tension when the thread is cut by the thread trimmer, and an upper surface of the sewing machine frame and between the auxiliary thread tension and the thread winding. A thread pulling member that moves from the standby position to the operating position, pulls out a predetermined amount of the upper thread from the thread winding, and returns to the standby position during the thread trimming to loosen the predetermined amount of the upper thread. It is a unique thread trimming sewing machine.

[0007]

During sewing, the upper thread unwound from the thread top is given an appropriate tension by the auxiliary thread tension and the thread tension. When sewing is completed and an instruction for thread trimming is input, the tension released from the tension applied to the upper thread by the tension releasing means is released.
The tension is applied to the upper thread only from the auxiliary thread tension. In addition, a thread pulling member disposed between the auxiliary thread tension and the thread spool moves from the standby position to the operating position, and draws a predetermined amount of the upper thread from the thread winding. At the time of thread trimming, the thread returns to the standby position to make a predetermined amount of slack in the upper thread. In this way, when the catching portion of the thread cutting means rotates to catch the sewing thread, the upper thread is also pulled in the rotating direction. At this time, the upper yarn is supplied with a loosened amount by the yarn pulling member, but the supplied upper yarn is subjected to a tension necessary for thread cutting by the auxiliary yarn tension. In addition, since the tension specified for the type of thread can be added by the auxiliary thread tension, the upper thread is not unnecessarily fed out at the time of catching the thread by the thread cutting means. There is no variation in yarn length. In addition, since a certain amount of slack is supplied to the upper thread by the thread pulling member, the upper thread is pulled by the thread take-up spring after thread trimming, and the tension of the upper thread is pulled out from the thread spool. Do not fall out.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view of the thread trimming sewing machine of the present embodiment. The thread trimming sewing machine 10 of the present embodiment includes a sewing machine bed 11.
And a sewing machine frame 12 provided standing upright from the sewing machine bed 11.

In FIG. 1, on the upper right side of the sewing machine frame 12,
A needle thread stand (not shown) is provided, and an upper thread T unreeled from the thread threader passes through two holes formed in the thread guide 13 and extends below the sewing machine frame 12. It is led to the head 14.

The sewing machine head 14 is provided with an auxiliary thread tensioner 15 for applying a necessary tension to the upper thread at the time of thread trimming, which will be described later. It can be applied to the tone 15. Auxiliary thread tension 1
5 is two tone plates 15a, 15b (FIG. 3) and a tone plate 15
a, which has a conical spring 15c for urging the
By rotating 5d, the tension can be adjusted. The auxiliary thread tensioner 15 applies a tension to the upper thread T necessary for thread trimming described later.

The upper thread T that has passed through the auxiliary thread tension 15 passes through the thread hook 19 and is positioned below the auxiliary thread tension 15.
Will be guided to. The thread tension 16 is the auxiliary thread tension 15 at the time of sewing.
It also applies a predetermined tension to the upper thread and has two tone plates and a conical spring (both not shown) for urging the tone plates. The tension of the upper thread is adjusted by sandwiching the upper thread T between the tone plates. Further, tension releasing means for releasing the tension applied to the upper thread by the thread tensioner 16 is provided in the sewing machine frame 12, and this tension releasing means acts at the time of thread trimming described later to bias the conical spring. Then 2
The tension applied to the upper thread T is released by releasing the urging elasticity of the tone trays. As the tension releasing means, the same means as in the related art can be used, and therefore, detailed description is omitted here.

The thread tensioner 16 is provided with a thread take-up spring 16a which is urged by spring means (not shown). The thread take-up spring 16a is provided to absorb slack generated in the upper thread T due to thread pull-in by a hook (not shown) during a sewing cycle of the sewing machine.

The upper thread T is guided from the thread take-up spring 16a through the thread hook bending plate 20 and the thread hook 21 to the balance device 17 which operates in accordance with the vertical movement of the sewing machine needle 18 and tightens the sewing thread. The thread is guided to the sewing needle 18 through the thread hooks 22 and 23.

Next, the yarn pulling member 30 which is a feature of the present invention.
Will be described. The yarn pulling member 30 of the present embodiment is provided between the yarn guide 13 and the auxiliary yarn tension 15, and loosens the upper yarn T before being guided by the auxiliary yarn tension 15. As shown in FIGS. 2 and 3, a base 32 is fixed to a rear surface of the sewing machine frame 12, and a bracket 33 that stands substantially vertically from the rear surface of the sewing machine frame 12 is provided on the base 32. ing. A solenoid 31 is fixed to one surface (the right side in FIG. 2) of the bracket 33, and the solenoid 31 has a drive arm 34 protruding from the other surface of the bracket 33 so as to be rotatable. Further, a bent operation arm 35 is fixed to the drive arm 34. The operation arm 35 rises obliquely upward from the drive arm 34 and further extends toward the near side along the upper surface of the sewing machine frame 12. are doing. Operating arm 35
Is provided with a hole 35b at the tip of. The upper thread T passes from the thread guide 13 to the auxiliary thread tensioner 15 through the hole 35b. The operating arm 35 in the standby position is, as shown by a solid line in FIG. 3, a contact portion 35 attached to the operating arm 35 below.
a and the elastic member 36 arranged on the sewing machine frame 12 are in contact with each other.

Below the sewing machine bed 11, a shuttle device and a thread cutting device (not shown) are provided. The thread trimming device includes a capturing section that rotates and captures the upper thread T and the lower thread, and a blade section that cuts the sewing thread captured by the capturing section. When a thread trimming solenoid (not shown) is energized in response to a thread trimming instruction, the rotation of the lower shaft is transmitted to the catching unit via the driving force transmitting means (not shown), and the catching unit rotates around the shuttle device. To catch the yarn. About the structure of this thread cutting device, since the same structure as the conventional one can be used, detailed description is omitted.

Next, the operation of the present embodiment will be described with reference to the timing chart of FIG. In the present embodiment, the instruction of thread trimming is performed by depressing a pedal (not shown) for instructing sewing on. Further, the thread cutting solenoid and the thread pulling member 30 of the thread cutting device are provided.
The timing of energizing the solenoid 31 is controlled by the position of the sewing machine needle 18, and the position of the sewing machine needle 18 is controlled by a magnet provided on a handwheel that rotates together with the main shaft of the sewing machine. The determination is made by two position sensors provided on the sewing machine frame 12. Regarding the configuration of the magnet and the position sensor, the same configuration as that of the related art can be used, and the description is omitted.

When the user finishes the sewing operation and depresses the pedal again to instruct thread trimming, the solenoid 31 of the thread pulling member 30 moves the needle position of the sewing machine needle 18 from the lower stop position to the upper stop position. The power is supplied after waiting. The solenoid 31 rotates the drive arm 34 in the counterclockwise direction in FIG. 3, and moves the operation arm 35 to the upper position indicated by the two-dot chain line (operation position). As a result, the upper thread T is moved from the thread guide 13 to the auxiliary thread tension 15.
Between the thread tops. When the sewing machine needle 18 moves from the upper stop position to the lower stop position, the solenoid 31 is turned off, and the operating arm 35 returns to the original standby position. The upper thread T fed out by the operating arm 35 remains loose between the auxiliary thread tension 15 and the thread tension 13.

At the same time as the solenoid 31 is turned off, the thread cutting solenoid is turned on, and the thread cutting operation starts. The energization of the thread cutting solenoid causes the catching section of the thread cutting device to rotate around the shuttle device to catch the upper thread T and the lower thread, and cut them together with the blade. At this time, the upper thread T is pulled with the rotation of the catching portion, but is smoothly fed to the sewing needle 18 because the tension of the thread tension 16 has been released. Further, the upper thread T loosened by the thread pulling member 30 is supplied to the thread tension 16, but at this time, the tension is supplied by the auxiliary thread tension 15 and supplied. Therefore, the upper thread is not unnecessarily fed out to the sewing needle 18, and the sewing needle 1 is not threaded after thread trimming.
The length of the upper thread remaining from 8 does not vary.

In this way, when the sewing needle 18 is again raised to the upper stop position, the power to the thread cutting solenoid is turned off, the catching portion of the thread cutting device returns to the original position, and the tension of the thread tension 16 returns. . The movement of the sewing needle 18 also stops, and the thread trimming operation ends.

[0020]

According to the present invention, the upper thread is tensioned by the auxiliary thread tension at the time of catching the thread by the thread cutting means, so that the upper thread is not unnecessarily fed out, and the upper thread remaining on the needle after thread cutting is removed. There is no variation in length. Further, the tension required at the time of thread trimming can be added for each type of thread by adjusting the auxiliary thread tension, so that the remaining length of the upper thread after thread trimming can always be stabilized.

Further, since a certain amount of slack is supplied to the upper thread by the thread pulling member, the tension of the upper thread does not fluctuate when the upper thread is pulled out from the thread after the thread is trimmed. The remaining length of the upper thread is stabilized, and after thread trimming, the upper thread is not pulled off from the sewing machine needle by the thread take-up spring. Further, since the thread pulling member is disposed on the upper surface of the sewing machine frame and does not operate in front of the user even if the thread pulling member operates, there is no need for bothering.

[Brief description of the drawings]

FIG. 1 is a front view of a thread trimming sewing machine according to an embodiment of the present invention.

FIG. 2 is a top view of the thread trimming sewing machine according to the present embodiment.

FIG. 3 is a sectional view taken along the line AA in FIG. 1;

FIG. 4 is a timing chart of needle positions and respective solenoids in the thread trimming sewing machine according to the present embodiment.

FIG. 5 shows a front view of a conventional thread trimming sewing machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Thread trimming machine 15 Auxiliary thread tension 16 Thread tension 16a Thread take-up spring 30 Thread shift member 31 Solenoid 35 Operating arm

Claims (1)

(57) [Claims] 1. A threading means having a catching portion for rotating a standby position to an operating position and catching a sewing thread, a blade portion for cutting the sewing thread captured by the catching portion, and being provided on a sewing machine frame and being unwound from a thread spool. An auxiliary thread tension for applying a tension necessary for thread trimming to the obtained upper thread, and a thread tension for applying a predetermined tension to the upper thread together with the auxiliary thread tension, wherein the upper thread passing through the auxiliary thread tension is hung; A thread take-up spring provided in close proximity to the thread tension to absorb slack of the upper thread during a sewing cycle; tension release means for releasing tension applied to the upper thread by the thread tension during thread trimming by the thread trimmer; It is disposed on the upper surface of the sewing machine frame and between the auxiliary thread tension and the bobbin, moves from a standby position to an operating position, pulls out a predetermined amount of upper thread from the bobbin, and returns to a standby position at the time of the thread trimming. The specified amount of needle thread A thread trimming sewing machine, comprising: a thread pulling member for making lugs.