JPH0528158B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides a sewing machine using a horizontal hook,
The present invention relates to a thread cutting device that cuts threads after sewing is completed.

[Conventional technology and its problems]

Generally, a sewing machine using a vertical hook is equipped with a thread cutting device that traps and cuts thread by horizontally reciprocating a movable knife between the hook and the throat plate.

However, when the above-mentioned thread trimming device is applied to a sewing machine using a horizontal hook, sufficient thread cutting performance cannot be obtained. No thread cutting device was provided.

In other words, in a vertical hook sewing machine, since the thread is located approximately vertically from the needle hole in the throat plate to the hook, the thread can be reliably caught and cut by a moving knife that moves horizontally. On the other hand, in a horizontal hook sewing machine, as shown in FIG. 3, the thread I (I ₁ indicates the upper thread and I 2 indicates the lower thread) runs from the needle hole 1a formed in the throat plate 1 to the hook ₂ . Since the thread I is located in an inclined position, the moving knife 3 may not be able to capture the thread I, resulting in frequent cutting errors. In particular, the upper thread I ₁ is caught on the tip of the outer hook and goes around the outer periphery of the inner hook, and is in a nearly horizontal state, so there is a high possibility that it will not be caught by the moving knife 3, and it will not be able to fully perform its function as a thread trimming device. I couldn't do it.

The present invention was made in view of the above-mentioned problem, and an object of the present invention is to provide a thread cutting device that can reliably cut thread in a horizontal hook sewing machine.

[Means to solve the problem]

This invention includes a thread presser member that presses the upper thread and lower thread downward at an intermediate position between the needle hole and the hook when the movable knife horizontally reciprocates between the throat plate and the hook. It was established.

[Effect]

In this invention, when the moving knife is operated, the thread holding member presses the sewing thread downward and holds it in a state close to perpendicular to the needle hole, so the horizontal movement path of the moving knife crosses the thread being held. , it is possible to reliably capture and cut the yarn.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In the figure, a lower shaft 4 rotates in conjunction with a main shaft (not shown), and is rotatably supported by the sewing machine frame M. Reference numeral 7 denotes a hook shaft which is interlocked with the lower shaft through a gear 5, and is supported perpendicularly to the sewing machine frame. 8
9 is an outer hook fixed to the hook shaft 7, and 9 is an inner hook fitted into the outer hook 8. 10 is the inner pot 9
bobbin for storing the bobbin thread installed inside, 11 is the needle plate, 1
1a is a needle hole formed in this throat plate 11, and 12 is a cloth feeding tooth.

Further, 13 is a knife mount mounted on the sewing machine frame M so as to be rotatable about the rotation center shaft 14, and 15 is a movable knife that rotates about the rotation center shaft 14 together with the knife mount 13. A hook-like thread catching portion 15a and a blade portion 15b are formed at one end thereof. 16 is a movable knife link having one end pivoted to the knife mount 13 and the other end pivoted to the thread cutting link 17. In addition, the thread cutting link 1
7 is supported at one end by the sewing machine frame M so as to be rotatable around a fulcrum shaft 18, and is always
In the figure, the fulcrum shaft 18 is
It is biased clockwise around the center. 17
Reference numerals a and 17b denote rollers provided at the middle portion and the other end portion of the thread cutting link 17.

19 is a thread trimming cam that rotates together with the lower shaft;
On one side thereof is a roller 17 of the thread cutting link 17.
A cam surface (not shown) for reciprocating the shaft a in the axial direction of the lower shaft 4 is formed. Reference numeral 20 denotes a knife operating plate rotatably attached to the sewing machine frame M by a fulcrum shaft 21, and an operating link 22 that moves forward and backward in the direction of arrow A or B according to the operation of a thread trimming lever, etc. (not shown).
It rotates in conjunction with. Further, a concave holding portion 20a for holding the roller 17b of the thread cutting link 22 is formed on the knife operating plate. Reference numeral 23 denotes a looper contact rotatably attached to the sewing machine frame M at a rotation center shaft 23, and is normally biased counterclockwise in FIG. 1 by a predetermined biasing means.
One end 23a is the projection 20 of the actuation moving plate 20.
b, and the other end 23b is located on the side of the outer hook 8. A thread cutting looper 24 is provided horizontally between the throat plate 11 and the inner hook 9 and serves as a thread pressing member. This thread trimming looper 24 has a substantially U-shape in plan, and is supported at both ends by shafts 25 and 26 on the sewing machine frame M so as to be freely rotatable in the vertical direction. Located nearby. Further, the thread cutting looper 24 is always urged to rotate counterclockwise in FIG. 2 by an unillustrated urging means, and one side portion 24b
A locking portion 24c protruding downward from the looper contact 23 is in contact with the other end 23b of the looper contactor 23. In addition, 27
is a fixed scalpel that shears the thread between it and the movable knife 15.

Based on the above configuration, the operation will be explained next. At the end of sewing, the sewing machine is stopped at a position below the needle plate 11.

When the operator moves the actuating link 22 in the direction A by, for example, pushing down the operating lever, the knife actuating plate 20 rotates around the fulcrum shaft 21 . As a result, the roller 17 is moved from the holding portion 20a of the knife actuation plate 20.
b is removed, and the thread trimming link 17 rotates clockwise in FIG. Further, when the protrusion 20b moves due to the rotation of the knife actuating plate 20, the looper contact 23 rotates around the fulcrum shaft 23c, and the other end 23b moves to the right in FIG. do. As a result, the thread cutting looper 24, which is in contact with the looper contactor 23 at the locking portion 24c, is rotated around the shafts 25 and 26 by the biasing means, and the pressing portion 24a is lowered.

In this state, when the lower shaft 4 is rotated by a thread trimming signal or the like, the outer hook 8 captures the upper thread passing through the sewing machine needle and pulls out the upper thread. At this time, the intermediate portions of the threads I ₁ and I ₂ are pressed down by the pressing portion 24a and held in a nearly vertical state as shown in FIG.

Further, the roller 17a moves along the cam surface of the thread cutting cam 19, and the thread cutting link 17 moves along the rotation center shaft 1.
It moves back and forth around 8. Due to this reciprocating movement of the thread cutting link 17, the knife mount 13 connected via the movable knife link 16 performs a reciprocating rotational movement about the rotation center shaft 14. In conjunction with this, the movable knife 15 also reciprocates and rotates around the rotation center shaft 14 between the position shown by the solid line and the position shown by the two-dot chain line in FIG. At this time, the threads I ₁ and I ₂ are pressed by the pressing part 24 and held in a nearly vertical state from the needle hole 11a, so the horizontal movement path of the moving knife 15 crosses the threads I ₁ and I ₂ . This ensures that the threads I ₁ and I ₂ are captured by the capture portion 15 a of the moving knife 15 and cut between them and the fixed knife 27 .

In the above embodiment, the rotation of the thread trimming looper 24 is controlled by the rotation of the knife operating plate 20, but the thread trimming looper 24 is rotated in conjunction with a cam etc. provided on the lower shaft. Alternatively, it may be driven directly by a motor or the like.

〔Effect of the invention〕

As explained above, according to the present invention, when the moving knife is operated, the part of the sewing machine thread from the needle hole to the horizontal hook is pressed down by the thread presser member.
The moving scalpel makes it possible to reliably capture the yarn and provide sufficient cutting performance. Therefore, it is possible to extremely easily apply a thread cutting device to a horizontal hook sewing machine, which has been considered difficult in the past, and it is possible to improve the functionality of the horizontal hook sewing machine.

[Brief explanation of drawings]

Fig. 1 is a plan view showing an embodiment of the present invention, Fig. 2 is a side view of the same as shown in Fig. 1, and Fig. 3 is a side view showing an example in which a thread cutting device is applied to a conventional horizontal hook sewing machine. It is. 8... Outer hook, 9... Inner hook, 11... Throat plate, 15
...Moving knife, 24...Thread cutting looper (thread pressing member), 27...Fixed knife, _I1 ...Upper thread, _I2 ...Lower thread.

Claims (1)

[Scope of Claims] 1. A movable knife that horizontally reciprocates between the throat plate and the horizontal hook catches the upper thread and bobbin thread extending downward from the needle hole in the throat plate, and shears them between the needle thread and the lower thread with a fixed knife. A thread cutting device for a horizontal hook sewing machine, characterized in that a thread pressing member is provided that presses down the upper thread and lower thread at an intermediate portion between the needle hole and the hook when the movable knife is operated. thread cutting device.