JPH04336095A - Threading device for sewing machine - Google Patents

Abstract

PURPOSE:To considerably facilitate the threading work for a needle hole by installing a sucking tool which can be set at a position for allowing a suction port for sucking thread to communicate to one edge of the needle hole and a position where the vertical movement of the needle is not obstructed after retreat, on the side part of the needle. CONSTITUTION:In the state where a needle 3 rises to a top dead center, the vertical movement is suspended, and a position changing means operates, and the peripheral edge 18 of the suction port 17 of a sucking tool 11 is closely attached on the peripheral edge 4a' at one edge 4a of the needle hole 4 of the needle 3, and the sucking tool 17 is advanced to a communication position where one edge 4a and the sucking port 17 communicated. If a vacuum device operates in this state, an air stream reaches the inside of the needle hole 4, passing through the other edge 4b as shown by the arrow 30 from outside the needle hole 4, and further reaches a suction chamber 14, passing through one edge 4b, suction port 17, nozzle 13, and a communication port 15. When the top edge 31a of a thread is set close, the thread 31 is guided to the other edge 4b, sucked by the air stream. When the thread 31 is driven out, the top edge 31a is introduced into the needle hole 4a, and further reaches the suction chamber 14 through the suction nozzle 13. Then, the vacuum device is brought into stop, and the sucking tool 11 is retreated to a retreat position by the position changing means, and sewing is started.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a threading device for a sewing machine, which is used for passing thread through the needle hole of a sewing needle in the sewing machine.

0002

[Background Art] When threading a thread through the needle hole, conventionally, first, the part near the tip of the thread is picked up with the fingertips so that the tip of the thread faces one end of the needle hole, and then the fingertips are brought closer to the needle. As a result, the thread is pushed into the needle hole from its tip.

0003

[Problems to be Solved by the Invention] In the case of the above-mentioned work, there is a problem in that since the needle hole is small, it is difficult to first expose the tip of the thread to the needle hole. Furthermore, when pushing the thread into the needle hole, if the thread is weak, it easily bends between the fingertip and the needle hole, making it very difficult to push the thread.

The present invention was made in order to solve the problems (technical problems) of the prior art described above, and the thread is drawn into the needle hole by an air flow, so that the operation of threading the thread through the needle hole is carried out. It is an object of the present invention to provide a threading device for a sewing machine that can be easily threaded.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the threading device for a sewing machine according to the present invention is provided with a needle that can freely move up and down, and a suction device for suctioning thread is provided on the side of the needle. The suction tool is provided with a suction device that can be freely moved between a position where the suction port communicates with one end of the needle hole of the needle and a position where the suction port is retracted from there and does not impede the vertical movement of the needle.

[0006]

[Operation] When the suction port of the suction tool is brought into close contact with one end of the needle hole, an air flow is generated from the other end of the needle hole toward the inside of the needle hole. When the tip of the thread is brought near the other end of the needle hole in this state, the tip is directed toward the needle hole by the air flow. Then, when the thread is let out, the thread is drawn into the needle hole in order from the tip by the air flow.

[0007]

Embodiments The drawings showing embodiments of the present application will be described below. In FIG. 1 showing a part of a sewing machine head, 1 is a base frame, 2 is a needle bar that can move up and down, and a sewing needle 3 is attached to the lower end of the needle bar.
is installed. 2 in FIG. 2 is the needle hole of the needle 3. Referring again to FIG. 1, reference numeral 5 denotes a vertically movable cloth presser, and 6 denotes a presser part of the cloth presser 5, which has a through hole 7 through which the needle 3 is inserted, as shown in FIG. 2(A). There is.

Next, 10 shown in FIG. 1 is a threading device,
The apparatus will be explained below based on FIGS. 1 and 2. 11
is a suction tool, and is composed of, for example, a hollow suction box 12 and a suction nozzle 13 attached thereto. The suction box 12 is made of a hard material such as metal or hard synthetic resin, and has a suction chamber 14 inside, a communication port 15 in a part of the peripheral wall, and a connection port to a vacuum device in the other part. 16 each. The suction nozzle 13 is made of a material having good flexibility and adhesion to the side surface of the needle 3, such as silicone rubber, and is fixed to the suction box 12 with one end communicating with the communication port 15. 17 indicates a suction port at the other end of the suction nozzle 13, as shown in FIG.
As shown in (B) and (C), it is formed to be sufficiently larger than the one end 4a of the needle hole 4 to ensure communication with the one end 4a. Reference numeral 18 indicates the periphery of the suction port 17, which is formed in a shape corresponding to the periphery 4a' of one end 4a of the needle hole 4 to ensure close contact with the periphery 4a'. Incidentally, the suction tool 11 may be a simple cylindrical body for suction provided with a suction port 17 at one end.

Next, reference numeral 20 denotes a repositioning means for repositioning the suction tool, which is attached to the base frame 1 of the sewing machine with a support rod 21, and has a reciprocating rod 22 that can move forward and backward in the direction of the arrow. The suction box 12 is attached to the tip of the retractable rod 22. For example, a solenoid is used as such a position changing means. An air cylinder may also be used. Reference numeral 24 denotes a vacuum device, which is composed of, for example, a compressor 25 and a vacuum generator 26 that generates a vacuum by receiving air supplied from the compressor 25. It is connected to 12 connection ports 16. As the vacuum device 24, a vacuum pump or a suction blower may be used.

Next, the operation of threading the needle hole 4 using the threading device 10 in the sewing machine will be explained. The vertical movement of the needle 3 is stopped when the needle 3 has risen to the top dead center or a position close to it. Next, the position changing means 20 is operated to move the suction tool 11 forward from the retracted position shown in FIG. 1 toward the needle 3, and as shown in FIGS. 18 is brought into close contact with the peripheral edge 4a' of one end 4a of the needle hole 4 in the needle 3, and the needle 3 is advanced to a communicating position where the one end 4a and the suction port 17 communicate with each other. In this case, the needle hole 4 and the suction tool 1
Even if there is some vertical and horizontal positional deviation between the
Since the suction nozzle 13 is highly flexible, the above-mentioned close contact is reliably achieved, and since the suction port 17 is sufficiently larger than the one end 4a of the needle hole 4, it is possible to ensure communication between the two.

Once the above conditions are established, the vacuum device 24 is activated. Then, from the outside of the needle hole 4 (B) and (C) in Fig. 2
As shown by the arrow 30, an air flow is created which passes through the other end 4b and into the needle hole 4, and further passes through the one end 4a, the suction port 17, the inside of the nozzle 13, and the communication port 15 toward the suction chamber 14. Next, as in the case of normal threading, pick up the part near the tip of the thread to be passed through the needle hole 4 with your fingertips, and insert the tip 31a of the thread 31 into the needle hole as shown in FIGS. 2(B) and 2(C). Get closer to 4. Then, the tip 31a of the thread is (
Even if there is some lateral deviation as shown in B) or vertical deviation as shown in (C), it will be guided toward the other end 4b by the airflow in the direction of the arrow 30. Therefore, if the operator continues to let out the thread 31, the tip 31a will naturally enter the needle hole 4. Then, if you continue to unwind the thread, 31
From the tip, the needle passes sequentially through the needle hole 4, passes through the suction nozzle 13, and reaches the suction chamber 14.

[0012] As described above, the thread 31 has a necessary and sufficient length.
When the suction tool 11 passes through the needle hole 4, the vacuum device 24 is stopped, and the position changing means 20 moves the suction tool 11 back to the retracted position. After that, you can start sewing as you would with a normal sewing machine.

Next, the position of the suction tool 11 can be changed by moving forward or backward, such as a position where the suction port 17 is in communication with one end 4a of the needle hole 4, and a position where the suction tool 11 does not interfere with the vertical movement of the needle 3. For example, it may be carried out along the routes shown by the two-dot chain arrows 33 and 34, respectively, in FIG. 1, or any other route.

[0014]

[Effect of the invention] As described above, in the present invention, the needle 3
When passing a thread through the needle hole 4 of the needle hole 4, the suction port 17 of the suction tool 11 is connected to one end 4a of the needle hole 4, and the tip 31a of the thread 31 is simply brought near the needle hole 4. Since the tip 31a of the thread is guided toward the needle hole 4 by the inward air flow, it has the advantage that the tip 31a of the thread can be brought into contact with the needle hole 4 very easily.

[0015] Moreover, after the threads are drawn as described above, as the threads are let out one after another, the thread 31 is drawn into the needle hole 4 from its tip 31a by the airflow flowing through the needle hole 4. , it has the advantage that even a weak thread can be easily inserted.

As described above, the threading device of the present invention has the advantage that threading through the needle hole 4 can be carried out extremely easily.

[Brief explanation of drawings]

FIG. 1 is a side view of a threading device in a sewing machine.

[Fig. 2] (A) is an enlarged cross-sectional view taken along the line II-II in Fig. 1 with the suction tool close to the needle, (B) is a cross-sectional view showing the suction port communicating with the needle hole, and (C) is a sectional view taken along the line CC in (B).

[Explanation of symbols]

3 needle 4 Needle hole 11 Suction tool 17 Suction port 31 Thread 31a Tip

Claims (1)

[Claims] 1. A sewing machine equipped with a vertically movable needle, wherein a suction tool equipped with a suction port for suctioning thread is provided on the side of the needle at a position where the suction port communicates with one end of the needle hole of the needle. A threading device for a sewing machine, characterized in that the threading device is provided in a position that can be freely changed to a position where it is retracted from there and does not obstruct the vertical movement of a needle.