JP2876810B2 - Sewing machine thread trimmer - 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 cutting device for a sewing machine, and more particularly to a moving blade which holds an upper thread and a lower thread and cooperates with a fixed blade fixed to a sewing machine bed to cut the upper thread and the lower thread. The present invention relates to a thread cutting device for a sewing machine.

[0002]

2. Description of the Related Art As a conventional thread trimming device for a sewing machine, FIG.
The following are known. The thread cutting device of the sewing machine includes a movable blade 22 rotatably arranged on the outer periphery of a vertical hook device 21 and a fixed blade 2 fixed to a lower surface of a sewing machine bed.
3 is provided. The movable blade 22 has a capturing portion 24 formed of a groove formed to be immersed in one side end, and a blade portion 25 is provided at an end of the capturing portion 24. The fixed blade 23 has a blade portion 26 formed at the tip, and is installed such that the blade portion 26 faces the blade portion 25 of the movable blade 22.

[0003] When an instruction to cut the sewing thread is input, the movable blade 22 rotates in the direction of arrow E in conjunction with the rising of the needle 20 from the needle plate, and catches the upper thread T and the lower thread U.
Then, the blade portion 26 of the fixed blade 23 and the blade portion 25 of the movable blade 22
And cut it.

[0004]

Usually, the upper thread T and the lower thread U
5 are separated by the stitch width, as is clear from FIG. However, in the above-described sewing machine thread trimmer, since the cutting of the upper thread T and the lower thread U is performed by the same blade, the upper thread T and the lower thread U which hang down from the sewing object 27 as shown in FIG. , The lower thread U is longer than the upper thread T.

Accordingly, an object of the present invention is to provide a thread cutting device for a sewing machine that cuts an upper thread and a lower thread so that the remaining thread has the same length.

[0006]

Configuration of the Invention

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, a technical solution taken in the present invention is a needle plate having a needle hole formed therein and a vertical type needle plate provided below the needle plate. A shuttle device, a movable blade arranged to rotate the outer periphery of the vertical shuttle device toward the near side, and the movable blade fixed to the lower surface of the sewing machine bed such that a tip end thereof is closer to the front side than the needle hole. In the thread cutting device of a sewing machine having a fixed blade that cuts an upper thread and a lower thread by meshing with a blade, the movable blade is immersed from a front end in a direction parallel to a rotation direction of the movable blade, and is inserted into a rear end. An upper thread groove provided with a blade portion, and a lower thread groove provided parallel to the upper thread groove and deeper than the upper thread groove from the front end and provided with a lower thread blade portion at the far end. The fixed blade is formed so as to face the upper thread blade, and the upper blade is configured to cut the upper thread in cooperation with the upper thread blade. A fixed blade for the lower thread, which is provided adjacent to the fixed blade for the upper thread and protrudes from the fixed blade for the upper thread and cooperates with the blade portion for the lower thread to cut the lower thread. It is a thread cutting device for a sewing machine.

[0008]

The upper thread is passed through the upper thread groove of the movable blade, and the upper blade fixed to the lower surface of the sewing machine bed provided at the end of the upper thread groove by the rotation of the movable blade. It is cut between the fixed blade. The bobbin thread is passed through the lower thread groove of the moving blade, and the lower blade fixed to the lower surface of the sewing machine bed and the lower thread blade provided at the end of the lower thread groove by the rotation of the moving blade. Cut between blades. The lower thread groove is provided deeper than the upper thread groove, and the lower thread fixed blade is projected more than the upper thread fixed blade. At the distance, the upper thread is slightly longer than the lower thread. However, since the bobbin thread hangs from the sewn object at a distance corresponding to the stitch width, the lengths of the threads hanging from the sewn object when cut are substantially equal.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of a thread cutting device of the sewing machine according to the present embodiment. Reference numeral 1 denotes a needle hole of a needle plate (not shown). An object to be sewn is placed on the upper surface of the needle plate, and the needle 3 is sewn by moving up and down so as to advance in the direction of arrow A. Below the needle hole 1, a vertical hook device 2 is provided. The vertical shuttle device 2 includes an outer shuttle 2a and an inner shuttle 2b, and the outer shuttle 2a is rotatable in the direction of arrow B.

A movable blade 4 is rotatably disposed on the outer periphery of the vertical shuttle device 2. The movable blade 4 is formed with two grooves that are recessed rearward from the near side in parallel with the rotation direction of the movable blade 4. The upper left groove in FIG. 1 is the upper thread groove 41, and the upper thread groove 41 is provided with an upper thread blade portion 41 a at the far end. A lower thread groove 42 is formed adjacent to and parallel to the upper thread groove 41. The lower thread groove 42 is the upper thread groove 41
The lower end is provided with a lower thread blade portion 42a at a depth end similar to the upper thread groove 41.

Normally, the movable blade 4 is on standby on the other side of the vertical shuttle 2, and when a thread cutting instruction is issued, the movable blade 4 moves the needle 3 from the lower position to the upper position in conjunction with the main shaft of the sewing machine. While ascending to the position, it rotates forward (in the direction of arrow C), catches the upper thread T and the lower thread U, and cuts the upper thread and the lower thread in cooperation with a fixed blade described later. After the cutting, it rotates in the direction of arrow D and returns to the standby position.

Next, the fixed blade 5 will be described. The fixed blade 5 of this embodiment is fixed to a sewing machine bed (not shown) from below by screws or the like, and is composed of an upper thread fixed blade 51 and a lower thread fixed blade 52. The upper thread fixed blade 51 and the lower thread fixed blade 52 are disposed such that the distal ends thereof face the moving blade 4. Further, the distal end of the lower thread fixed blade 52 is disposed so as to protrude beyond the distal end of the upper thread fixed blade 51. The distance between the tip of the lower thread fixed blade 52 and the tip of the upper thread fixed blade is equal to the distance between the lower thread blade portion 42a and the upper thread blade portion 41a of the movable blade. Can be adjusted to the average seam width.

Next, the operation will be described. When the sewing operation is completed, the sewing machine stops at a position below the lower surface of the workpiece. At this time, the upper thread T is hooked on the blade point (not shown) of the vertical hook device 2 and is in a state of starting to pass through the outer periphery of the vertical hook device 2. Then, when a thread cutting command is issued by the user, the needle 3 moves up, and at the same time, the movable blade 4 rotates in front of the standby position (in the direction of arrow C) in conjunction with the main shaft.
The upper thread T, which is lower than the needle 3 at the tip of the moving blade 4, is hooked. The upper thread T between the vertical hook device 2 and the sewing object is inserted into the upper thread groove 41, and the lower thread U Are passed through the lower thread grooves 42, respectively. As the needle 3 moves up, the movable blade 4 rotates, and the upper thread T is stretched between the upper thread groove 41 and the tip of the movable blade 4. And the moving blade 4 is fixed blade 5
The upper thread T and the lower thread U are respectively cut.

As shown in FIG. 2, the positions where the upper thread T and the lower thread U protrude from the workpiece 6 are shifted by the stitch width 7 and are not the same. However, according to the present embodiment, since the positions where the upper thread T and the lower thread U are cut away by the stitch width 7, the length of the upper thread T and the lower thread U which hangs from the sewing object 6 is shown in FIG.
Can be the same length. Therefore, the quality of the sewn product is improved. In addition, the length of the upper thread from the sewing object can be reduced as compared with the related art.

In this embodiment, an example in which the fixed blade 5 is fixed to the sewing machine bed has been described. However, if the mounting positions of the upper thread fixed blade and the lower thread fixed blade can be finely adjusted, they can be more reliably achieved. The length of the upper thread and the lower thread can be the same even when the width of the stitch changes.

[0016]

According to the present invention, the lengths of the upper thread and the lower thread hanging down from the sewing object can be equalized, so that the quality of the sewn product can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a thread trimming device of a sewing machine according to the present embodiment.

FIG. 2 is a cross-sectional view of a sewing product when an upper thread and a lower thread are cut by the thread cutting device of the sewing machine according to the present embodiment.

FIG. 3 is a cross-sectional view of the sewing object cut by the thread cutting device of the sewing machine according to the embodiment.

FIG. 4 is a sectional view of a conventional thread trimming device of a sewing machine.

FIG. 5 is a cross-sectional view of an object to be sewn when an upper thread and a lower thread are cut by a conventional thread cutting device of a sewing machine.

FIG. 6 is a cross-sectional view of a sewing product cut by a conventional sewing machine thread trimming device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Needle hole 2 Vertical hook device 4 Moving blade 41 Upper thread groove 41a Upper thread blade 42 Lower thread groove 42a Lower thread blade 5 Fixed blade 51 Upper thread fixed blade 52 Lower thread fixed blade

Claims (1)

(57) [Claims] 1. A needle plate having a needle hole formed therein, a vertical hook device disposed below the needle plate, and an outer periphery of the vertical hook device arranged to rotate toward the near side. Sewing machine having a movable blade to be cut, and a fixed blade fixed to the lower surface of the sewing machine bed such that the tip end is on the front side of the needle hole and meshing with the movable blade to cut the upper thread and the lower thread. At
The moving blade has a groove for an upper thread that is immersed from a near end in a direction parallel to a rotation direction of the moving blade and has a blade portion for an upper thread at a rear end, and a groove for the upper thread that is parallel to the upper thread groove. A lower thread groove with a lower thread blade portion is formed at the far end, which is deeper than the groove and immerses from the near end,
The upper blade fixed blade for cutting the upper thread in cooperation with the upper thread blade portion, the fixed blade is disposed to face the upper thread blade portion,
A sewing machine comprising: a lower thread fixed blade provided adjacent to the upper thread fixed blade and protruding from the upper thread fixed blade to cut a lower thread in cooperation with the lower thread blade. Thread trimming device.