JPS6349269Y2 - - Google Patents

Description

[Detailed description of the invention] (Technical field) The present invention relates to a thread cutting device for a sewing machine, and in particular, it is designed to be able to cut threads with a small thread tension, and to provide sufficient tension to the needle attached to the needle bar during thread cutting. This invention relates to a thread cutting device for a sewing machine that allows thread length to remain.

(Prior Art) Conventionally, various types of sewing machine cutting tools have been put into practical use. What is shown in FIG. 1 is an example of a thread cutting tool 1 currently in use, in which a blade portion 2a cut diagonally into a presser bar 2 of a sewing machine is formed. When cutting the thread with this thread cutting tool, the thread 3 inserted into the blade part 2a has the disadvantage that it cannot be cut well unless both ends of the thread 3 are held down with fingers and strongly pulled and pushed down. Almost the same drawbacks were found in thread trimmers. Further, since there is no part for guiding the thread 3 during thread cutting, it is difficult to draw the thread 3 into the blade portion 2a of the thread cutting tool 1. Also, when trimming the thread, the needle bar 4
Since there is not enough thread length left in the needle 5 attached to the needle 5, there is a drawback that the thread 3 comes off from the needle 5 when the needle bar 4 is raised.

(Purpose and solution) The present invention was devised to eliminate the drawbacks of the above-mentioned prior art, and its purpose is to connect the thread introduction part formed on the mount for attaching the cutter to the cutter. By pulling the thread into the part where the blade intersects at an acute angle and cutting it, the thread can be cut with a small thread tension. It's about making it easier. Another object of the present invention is to attach a thread trimmer to the lower end of the mounting member, which is located diagonally above and to the left of the needle attached to the lower end of the needle bar when facing the front of the sewing machine head. The goal is to leave enough thread length to prevent the thread from coming off the needle when the needle bar is raised. Still another object is to form a thread guide section at the lower end of the attachment member from the rear end toward the front end, to guide the thread along the thread guide section and to draw the thread into the thread cutter. It's about making it easier.

(Example) The present invention will be described below based on an example shown in the drawings. A thread cutting device 10 for a sewing machine according to the present invention includes a thread cutting tool 11 and a mounting member 12 to which the thread cutting tool is attached.

As shown in FIGS. 2 to 5, the thread cutting tool 11 includes a mounting base 13, a cutter 14, and a cover member 1.
5, and the mounting base 13 is formed into an L-shape, consisting of a horizontal portion 13a bent at a right angle and an upright portion 13b. As shown in FIG. 5, the horizontal portion 13a has a U-shaped notch 13c that is open on the left at its left edge, and one wall of the notch serves as a thread introduction portion 13d. There is. Further, a boss portion 13e is formed by stamping on the right side of the horizontal portion 13a.

The blade 14 is made of a flat plate, and has a blade portion 14 on one end surface.
a is formed. There is a hole 1 on the right side of the blade 14.
4b is formed, and the boss portion 13e of the mounting base 13 is fitted into the hole.

The cover member 15 covers the horizontal portion 13 of the mounting base 13.
It is fixed to the horizontal part 13a of the mount 13 by a twist 18 so as to cover the cutter 14 attached to the mount 13, and the left edge of the mount 13
A slightly larger notch 15a is formed opposite to the notch 13c. Also, cover member 1
A right wall portion 15b and a front wall portion 15c are formed on the right edge and front edge of the mounting base 13, respectively, and are bent so as to come into contact with the right edge and front edge of the horizontal portion 13a of the mounting base 13. Additionally, a mounting base 13 is provided on the front wall.
A bent portion 15d is formed so as to abut and cover a part of the lower surface of the horizontal portion 13a.

The cutter 14 is attached to the mount 13 so that the boss 13e of the mount 13 is fitted into the hole 14b, and the blade 14a intersects the thread introduction part 13d of the mount 13 at an acute angle. The right side surface 14c of the cover member 15 is in contact with the right wall portion 15b of the cover member 15, and is restrained from rotating.

As shown in FIG. 6, the face plate 12, which is an example of a mounting member, is disposed diagonally above and to the left of the needle 5 attached to the lower end of the needle bar 4 toward the front of the sewing machine head 19. The upright portion 13b of the mounting base 13 for the cutting tool 11 is fixed by a fixing means such as adhesive. Further, at the lower end of the face plate 12, there is a thread guide section 12 that is chamfered diagonally from the rear end toward the front end.
a is formed.

The present invention is constructed as described above, and its operation will be explained below. As shown in FIG. 6, a case will be described in which the thread 3 attached to the cloth 25 is cut with the thread cutter 11 fixed to the lower end of the face plate 12 disposed diagonally above and to the left of the needle 5. The thread is pulled out from a thread spool (not shown) and is continuous with the thread 3 inserted into the needle 5 attached to the needle bar 4. Grasp the fabric 25 with one finger and pull the thread 3. The cutter 14 is moved forward along the thread guide portion 12a of the face plate 12.
The blade part 14 is introduced into the intersection P (see FIG. 2) between the blade part 14a and the thread introduction part 13d of the mounting base 13.
When pulled downward at an acute angle with respect to a, the thread 3 connects to the back surface of the blade 14 and the horizontal part 13 of the mount 13.
a to increase the pressing force on the blade part 14a,
Improves thread cutting force. As a result, the thread 3 can be cut with a small thread tension, so there is no need to hold both ends of the thread 3 with your fingers and pull it strongly as in the past, but simply hold the cloth 25 with one finger and use the cutter 14. Blade part 1
It is only necessary to pull the thread 3 downwardly at an acute angle with respect to the thread 4a. Furthermore, the thread 3 is connected to the thread guide section 1 of the face plate 12.
Since it is guided by 2a and introduced into the thread cutting tool 11, the thread cutting operation becomes easy.

Further, since the blade part 14a of the knife 14 is covered with a cover member 15 to prevent it from coming into direct contact with the user, the user will not touch the blade part 20a and injure his fingers, and the cloth 25 will not be damaged. There's nothing to do. Further, the thread trimming tool 11 is fixed to a face plate 12 which is arranged at a diagonally upper left position sufficiently far away from the needle 5, and since sufficient thread length remains on the needle 5 after thread trimming, the needle bar 4 Even if the needle 5 rises, the thread 3 will not come out from the needle 5.

Note that the sewing machine thread cutting device 10 according to the present invention
The present invention is not limited to lockstitch sewing machines, but can also be used, for example, for thread trimming during overlocking in a sewing machine equipped with a lockstitch mechanism and an overlocking mechanism, a so-called compound sewing machine.

(Effects) The present invention is constructed and operates as described above, and the thread is drawn into the part where the thread introduction part formed on the mount for attaching the cutter intersects with the blade part of the cutter at an acute angle. Since the thread is cut with a slight thread tension, the thread can be cut with a small amount of thread tension, and as a result, the thread cutting operation becomes easy. In addition, the thread trimmer is attached to the lower end of the mounting member, which is located diagonally above and to the left of the needle attached to the lower end of the needle bar when facing the front of the sewing machine head, so that the needle has enough thread when trimming the thread. There will now be enough length left and the thread will not come off the needle when the needle bar is raised. Further, since a thread guide section is formed at the lower end of the face plate from the rear end to the front end, the thread is guided along the thread guide section and can be easily drawn into the thread cutter, etc., thereby providing various effects.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the thread cutting operation of a thread cutting tool of a sewing machine according to a conventional example, Figs. 2 to 6 relate to an embodiment of the present invention, and Fig. 2 is a plan view of the thread cutting tool of a sewing machine. , Fig. 3 is a longitudinal sectional view taken in the direction of - arrow in Fig. 2, Fig. 4 is a longitudinal sectional view taken in - arrow direction in Fig. 2, Fig. 5 is an exploded perspective view of the thread cutter, and Fig. 6 is a sewing machine head. FIG. 3 is a perspective view showing the thread cutting operation of the thread cutting device attached to the machine. 4 is a needle bar, 5 is a needle, 10 is a thread cutting device of the sewing machine, 11 is a thread cutting tool, 12 is a face plate which is an example of a mounting member, 12a is a thread guide portion, 13 is a mounting base, 1
3d is a thread introduction part, 14 is a blade, 14a is a blade part, 1
9 is a sewing machine head.

Claims (1)

[Scope of utility model registration request] In a sewing machine thread trimming device that is attached to a part of the sewing machine frame above the needle attached to the lower end of the needle bar that moves up and down, and consists of a thread guide section and a blade section, a mounting base 13, a blade 14, , a mounting member 12, and the mounting base 13 is connected to a horizontal portion 13a and an upright portion 1.
3b to form an L-shape, and the cutter 1 is attached to the horizontal part.
The thread introduction part 13d, which is formed in the horizontal part by fixing 4, intersects the blade part 14a of the cutter 14, and the upright part 13b of the mounting base 13
by attaching the horizontal portion 13a to the mounting member 12.
1. A structure of a thread cutting device for a sewing machine, characterized in that a guide portion 12a is formed at an end edge of the mounting member at a right angle and is chamfered at an angle.