JPH05237282A - Sewing machine - Google Patents

Abstract

PURPOSE:To prevent a needle thread from being drawn in at the initiation of a final sewing. CONSTITUTION:A needle thread hooking piece 14 which is extendible and retractable from and into a hook 5 comes into the hook 5 at the initiation of sewing. Then, the needle thread led around the hook 5 is hooked by the needle thread hooking piece 14. In this condition, the needle thread is pulled up by a thread take-up lever so that the needle thread shifts along the hooking piece 14, and the leading end of the needle thread which has been presented on a fabric is drawn in.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine adapted to sew a cloth by a lock stitch.

[0002]

2. Description of the Related Art A shuttle is provided under a needle plate, and a vertically movable needle is provided above the needle plate so as to descend toward a shuttle through a needle hole formed in the needle plate. There is. When the needle moves up and down and the hook rotates in conjunction with it, the upper thread supplied through the needle and the lower thread supplied from the bobbin in the hook sew the cloth on the needle plate.

[0003]

This conventional sewing machine has a problem in that the end of the upper thread remains on the upper surface of the cloth at the sewing start position for the cloth, which is unsightly.

The present invention has been made in order to solve the above-mentioned problems (technical problems) of the prior art, and enables the end of the upper thread to be pulled under the cloth at the sewing start point of the cloth. The purpose is to provide a sewing machine.

[0005]

In order to achieve the above object, the sewing machine according to the present invention is provided with an upper thread hooking piece which can be freely put in and taken out of a hook.

[0006]

[Operation] When sewing is started, the upper thread hooking piece enters the hook. Then, as the hook rotates, the upper thread passing under the hook is hooked on the upper thread hooking piece. After that, when the upper thread is pulled up by raising the balance, the upper thread moves along the portion hooked on the upper thread hooking piece. as a result,
The end of the needle thread that was on the cloth is pulled under the cloth.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 to 5 show constituent members of a known lockstitch sewing machine, 1 is a bed, 2 is a needle plate, 3 is a needle hole,
Reference numeral 4 indicates a shuttle driving shaft, and 5 indicates a shuttle. See also FIGS.
6 indicates a needle for sewing. Referring again to FIG.
Is a needle thread hooking mechanism. 12 is a mounting frame in the mechanism,
It is fixed to bed 1. Reference numeral 13 is a drive device attached to the attachment frame 12, and as an example, a rotary solenoid in which a drive shaft 13a reciprocally rotates is used. 14 is an upper thread hooking piece, which is formed in a bifurcated shape.
It is connected to 13a so that it can be moved in and out of the shuttle 5.

Next, the operation of the sewing machine having the above structure will be described with reference to FIGS. 2 and 3 to 5. Note that (A) to (F) in FIGS. 3 to 5 show the state at the time indicated by the same reference numeral in FIG. Also, in FIG. 3 to FIG.
Is a cloth to be sewn, and is horizontally moved along the upper surface of the needle plate 2 while being stretched on a cloth tension frame as is well known. 22 is a kettle 5
The lower thread 23 fed out from the inner bobbin and the upper thread 23 supplied through the needle 6 are respectively shown.

First, the operation of the sewing machine is started in the state of FIG. The length of the upper thread 23 indicated by the reference symbol L at the start is, for example, 65 mm. When the operation is started, the shuttle 5 starts rotating in the direction of the arrow, and the needle 6 starts descending. After that, the rotary solenoid in the needle thread hooking mechanism 11 shown in FIG.
The drive shaft 13a of 13 rotates in the direction of the arrow 16, and the upper thread hooking piece 14 enters the shuttle 5 as shown in FIGS. 3B and 5B. Further, the rotation of the shuttle 5 and the lowering of the needle 6 are continuously performed, and the sword tip 7 and the needle 6 of the shuttle 5 are in the state as shown in FIG. Then, as the rotation of the shuttle 5 continues, the upper thread 23 of the needle 6 is hooked by the sword tip 7, and as the shuttle 5 rotates, the upper thread 23 as shown in FIGS. 3 (C) and 5 (C). 23 goes under the kettle 5. When the hook 5 continues to rotate, the upper thread
23 is an upper thread hooking piece as shown in FIG. 4 (D) and FIG. 5 (D).
It will be in a state of being caught on 14.

In this state, as is apparent from FIG. 2, the needle thread 23 is pulled up in the direction of arrow 24 by raising the balance. Due to this pulling up, the upper thread 23 hooked on the upper thread hooking piece 14 moves along the upper thread hooking piece 14 as indicated by an arrow 25. By such movement of the upper thread 23, the end 23a of the upper thread 23
Is pulled under the cloth 21 as shown in FIG.
After that, the needle thread hooking piece 14 is returned to the original position, that is, the position outside the shuttle by the operation of the rotary solenoid 13, and the state shown in FIG. 4 (F) and FIG. 5 (F) is obtained. After that, the needle 6 is vertically moved, the shuttle 5 is rotated, and the balance is vertically moved as usual, and the main stitch is sewn to the cloth 21 by the upper thread 23 and the lower thread 22.

The upper thread hooking piece 14 is inserted into the hook 5 before the upper thread 23 passing through the hook 5 passes through the upper hooking piece 14 in the hook 5 as shown in FIG. If so, any time. Further, the withdrawal may be performed at any time after the time point (F) in FIG. 2 and before the upper thread 23 and the lower thread 22 are entangled by the lowering of the needle 6 and the rotation of the shuttle 5.

[0012]

As described above, according to the present invention, the cloth 21
At the beginning of sewing, the end 23a of the upper thread 23 can be pulled under the cloth 21, and there is an effect that the upper surface of the cloth 21 can be in a beautiful state with no thread end.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a bed in a sewing machine.

FIG. 2 is a time chart for explaining the operation.

3A to 3C are cross-sectional views showing a state of a main part of the sewing machine of FIG. 1 at the time points of FIGS. 2A to 2C.

4 (D) to (F) are cross-sectional views showing a state of a main part of the sewing machine of FIG. 1 at a time point of (D) to (F) in FIG.

5 (B), (C), (D), and (F) are cross-sectional views showing a state of a main part at each time point of (B), (C), (D), and (F) in FIG. (A cross-sectional view showing a state viewed from a direction orthogonal to FIGS. 3 and 4).

[Explanation of symbols] 2 needle plate 5 hook 6 needle 14 needle thread hook 23 needle thread

Claims (1)

[Claims] 1. A sewing machine provided with an upper thread hooking piece which can be freely put in and taken out of a hook.