JPS6121022Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) This invention relates to a cutting thread guide mechanism in a thread trimming sewing machine.

(Prior Art) FIG. 8 shows the main parts of a thread cutting device in a conventional thread cutting sewing machine. In this type of sewing thread cutting device, needle thread 1 and bobbin thread 2 are captured by the movement of a movable blade 3 and are cut by sliding contact with a fixed blade 4.

In order to prevent the upper thread 1 from coming off the tip 3a of the movable blade 3, a thread guide 5 is fixed to a machine frame (not shown) so as to be located between the movable blade 3 and the hook 6.

(Problems to be Solved by the Invention) Arranging the thread guide 5 between the movable blade 3 and the hook 6 means separating the hook 6 from the throat plate 7.

For this reason, the lowest point of the needle also points downward, and if the fabric is too thick, the needle clamping portion will hit the fabric, resulting in a problem that the range of fabric thickness that can be sewn becomes narrow. It also means making the needle thread loop larger.
There was a problem in that loop formation became unstable and skipped stitches occurred, resulting in a decrease in seam quality.

Furthermore, it is difficult to attach the thread guide 5 between the movable knife 3 and the hook 6, resulting in a problem that production efficiency is reduced.

This invention aims to solve these problems.

(Structure) (Means/effects for solving the problem) This invention uses a bobbin presser that works in conjunction with the thread trimming mechanism to press the bobbin in the hook and prevent the bobbin from idling during thread trimming. The above problem is solved by operating the device so that it is latched.

(Example) Hereinafter, an example of this invention will be described based on the drawings.

As shown in FIG. 5B, 17B is a thread handling part formed in the movable blade 17, and is formed by cutting deeply toward the blade part 17c of the movable blade 17 to near the blade part 17c. For this reason, the upper thread N after cutting
The remaining length of can be shortened.

In FIG. 1, reference numeral 10 denotes a hook shaft that is rotatably supported on the machine frame and rotates in conjunction with the main shaft (not shown) of the sewing machine, and a hook 1 that captures needle thread (not shown) at the left end.
1 (Fig. 5A) is fixed.

Reference numeral 13 designates a clutch body which is rotatably and axially movably fitted loosely on the hook shaft 10 and has a thread trimming cam 14, in which a locking portion 13A at the left end moves leftward on the hook shaft 10, and the hook shaft 10 By engaging with the engaging body 15 fixed to the hook, it is connected to the hook shaft 10 and rotates,
By moving backwards to the right on 0, the engaging body 1
5 and disconnect from the hook shaft 10. Reference numeral 16 denotes a thread cutting shaft parallel to the shuttle shaft 10 and rotatably supported on the machine frame.

Reference numeral 17 denotes a movable blade which is rotatably fitted loosely around the outer periphery of the hook 11 (FIG. 5A) to the hook bearing 18, and is connected to the thread trimming shaft 16 via a link 19 and a rotating arm 20. ing.

21 is a fixed blade whose base end is fixed to the machine frame, and movable blade 1
7 to cut the needle thread and bobbin thread.

A spring 22 normally acts to separate the movable blade 17 from the fixed blade 21, and has one end wound around the thread cutting shaft 16 and supported by the machine frame.

In Figures 3 and 4, 23 has one end attached to the thread cutting shaft 16.
The thread cutting operating arm is fixed to the hook and has the other end extending in the direction of the shuttle shaft 10, and has a roller 23A at the tip.

During this thread cutting, the operating arm 23 contacts and rotates with the rotation of the thread cutting cam 14, and moves the movable blade 17 in a direction in which it comes into sliding contact with the fixed blade 21.

Reference numeral 24 denotes a drive arm rotatably supported on a shaft 26 fixed on a support base 25 fixed to the machine frame, and at one end of this drive arm 24 is a pin 24A that engages with an annular groove 13B formed in the clutch body 13. A link 27 is rotatably supported at the other end.

A spring 28 is wound around the shaft 26 of the drive arm 24 and is hooked at one end to the pin 24A and the other end to the support base 25, and normally rotates the drive arm 24 clockwise to separate the clutch body 13 from the engaging body 15. It works like this.

29 is a plunger 29 in the middle part of the drive arm 24.
A is in contact with a solenoid as a driving means which is fixed on the support base 25. When the solenoid 29 is energized, the clutch body 13 moves to the left on the shuttle shaft 11, and the engaging body 15 and the clutch body 13 are engaged. The thread trimming cam 14 rotates, the thread trimming operating arm 23 rotates, and the movable blade 17 operates via the thread trimming shaft 16.

Reference numeral 30 denotes a bobbin holder whose one end is rotatably supported on a shaft 31 supported on the machine frame and whose middle portion is rotatably supported on the link 27. A presser pin 33 with a spring 32 interposed therebetween is provided.

Incidentally, instead of providing the spring 32 and the presser pin 33, a return spring 32A wound around the shaft 31 is provided as shown in FIG.
They may be connected to each other via the elongated hole 27A.

Next, the operation of the embodiment of this invention will be explained.

In a normal sewing process, the solenoid 29 is in a non-energized state as shown in FIG. Released pot shaft 1
0 is rotating, and the movable blade 17 is separated from the fixed blade 21 by the restoring force of the spring 22. When the sewing process is completed and the needle (not shown) stops at the lower position, the thread trimmer switch is turned on, and at the same time the needle begins to move to the upper position, the solenoid 29 is energized, the plunger 29A protrudes, and the drive arm 24 is moved counterclockwise. Rotate to. As a result, the clutch body 13 moves to the left on the shuttle shaft 11, and the locking portion 13A of the clutch body 13 engages with the engaging body 15, so that the clutch body 13
rotates integrally with the hook shaft 11.

Due to the movement and rotation of the clutch body 13, as shown in FIG.
As shown in FIG. 4, the thread trimming cam 14 is
The actuating arm 2 moves to a position facing the actuating arm 23 and rotates counterclockwise to come into contact with the roller 23A of the actuating arm 23.
Turn 3 clockwise.

As the operating arm 23 rotates clockwise, the thread cutting shaft 16 also rotates clockwise, and the movable blade 17 moves to the fixed blade 21.
move in the direction. At this time, due to the rotation of the drive arm 24, the bobbin presser 30 is moved through the link 27.
rotates clockwise about shaft 31 to press a bobbin (not shown).

FIG. 5 shows the state in which bobbin threads B and N are cut. In this state, the bobbin presser 30 is pressing the bobbin, and the needle thread N is in a state where it comes out of the hook 11 and is retained by the bobbin presser 30, so that the needle thread N is connected to the thread catching notch 17A of the movable blade 17 and the thread. Tension is applied to the needle thread N so that it does not come off the cutting notch 17B.

When the thread cutting is completed and the movable blade 17 returns to its original position, the solenoid 29 becomes de-energized and the spring 28
The drive arm 24 rotates clockwise due to the restoring force of
The clutch body 13 is moved rightward along the shuttle shaft 10. Therefore, the clutch body 13 is separated from the engaging body 15, and the thread trimming cam 14 is also removed from the thread trimming actuating arm 2.
It moves away from the position facing 3 and stops rotating.

At the same time, the bobbin presser 30 rotates counterclockwise and returns to its original position away from the bobbin.

[Effect of idea]

As mentioned above, according to this invention, the needle thread is caught by the bobbin holder during cutting, so the needle thread can be prevented from slipping out from the movable blade without requiring a thread guide like in the past. This has the effect of not increasing the gap between the hook and the throat plate, and therefore preventing the needle clasp from touching the fabric even when using thick fabrics, widening the range of fabric thickness that can be sewn. This has the effect of preventing skipped stitches because the thread loops do not become too large.
Further, since the movable blade and the bobbin holder are operated by one driving means, the number of parts can be reduced and production costs can be reduced.

[Brief explanation of the drawing]

Figure 1 is a bottom view of the cutting thread guide mechanism of this invention.
2 is a left side view of FIG. 1, FIGS. 3 and 4 are explanatory diagrams of the operation of the cam body 14 and the operating arm 23, and FIG. 5A is a perspective view of the main parts of the movable blade 17 and the bobbin holder 30.
FIG. 5B is a plan view of the movable blade 17, FIG. 6 is an exploded partial perspective view of the bobbin holder, FIG. 7 is a partial exploded perspective view showing another embodiment of the bobbin holder, and FIG. 8 is a conventional cutting thread guide. FIG. 3 is a partial perspective view of the mechanism. 13...Clutch body, 17...Movable blade, 24...
...driving arm, 29... solenoid as a driving means, 30... bobbin holder.

Claims (1)

[Scope of Claim for Utility Model Registration] A clutch body that is rotatably supported on a machine frame and has a cam body that is loosely fitted onto the hook shaft so as to be able to engage and disengage from the hook shaft, to which a hook with a bobbin case stored at one end is fixed. , a drive arm rotatably supported on the machine frame, one end of which engages the clutch body, and the other end rotatably supported on the machine frame and connected to the bobbin holder so as to press the bobbin; In connection with this, there is a movable blade that slides into fixed blade fixed to the machine frame and cuts the bobbin thread and needle thread, and a clutch body engages with the shuttle shaft to operate the movable blade and the bobbin presser cuts the needle thread when cutting the thread. A cutting thread guide mechanism in a thread trimming sewing machine comprising a single drive means that rotates a drive arm that hooks the needle thread, applies tension to the needle thread, and presses the bobbin.