JPS63315096A - Automatic yarn cutter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic thread cutting device that cuts thread using a thread cutting motor other than a sewing machine motor that rotates a main shaft.

1 digit Conventional thread trimming devices are often based on mechanical coupling mechanisms such as cams, links, gears, etc., and their driving method involves interposing a spring in the mechanical mechanism, so that when thread trimming is not activated, the moving knife is activated. A reciprocating drive means, such as a grooved cam, is used to move the movable knife to the active position during thread cutting operation against the spring, and return it to the non-active position again. Many things have been proposed.

The conventional thread trimming device configured in this way has the advantage of being able to repeat extremely stable thread trimming operations without any accidents using the biasing means and the reciprocating means. ,
On the other hand, in order to perform the thread cutting operation, the sewing machine motor requires a motor with a very large capacity, taking into account the spring resistance of the urging means and reciprocating means, the inertia of the mechanical coupling mechanism, friction loss, etc. In addition, because these biasing means and reciprocating means require a thread trimming device, many components are required, and the sewing machine is small in size, which is required for an automatic sewing system with a movable sewing machine and a fixed workpiece type.

This was an obstacle to the realization of a lightweight sewing machine.

In order to solve the above-mentioned problems, the present invention provides a sewing machine with a first motor that rotates the main shaft, a needle bar position detection means that detects the position of the needle bar, and a moving knife. and a movable knife detecting means that detects the position of the movable knife. After capturing the thread, the main shaft is rotated to a position where the needle thread does not come out through the needle hole when the cut thread is cut, and the cut thread is cut by the movable scalpel.

According to the present invention, a dedicated motor is provided for the thread trimming drive, the rotation of this motor is transmitted by a four-bar linkage mechanism, and a ratchet is provided in the intermediate transmission path to limit the rotation, thereby making it easier to Moreover, the initial settings and thread trimming control of the sewing machine can be performed reliably.

FIG. 1 is a perspective view of a sewing machine feeding device of an automatic sewing system with a movable sewing machine and a fixed workpiece type, which embodies the present invention. The sewing machine 1 is placed on a table 2.

Further, the table 2 is supported by guides 3a and 3b, and is moved in the Y direction by a feed screw 4 rotated by rotation of a motor 5 that feeds in the Y direction. Also, guides 3a, 3b, feed screw 4. A motor 5 for feeding in the Y direction is mounted on a Y direction feed base 6. Furthermore, the Y-direction feed base 6 is the X-direction feed base 7.
It is supported by guides 8a and 8b provided in the X direction, and is moved in the X direction by an X direction feed screw 9 rotated by the rotation of the X direction feed motor IO. Further, the sewing machine 1 is rotated by a sewing machine rotation motor 50. This sewing machine is mainly used for decorative sewing of cuffs and collars, and for joining together slacks, etc.

FIG. 2 is a front view of a sewing machine according to one embodiment of the present invention and a third embodiment of the sewing machine.
The figure is a side view as seen from arrow A in FIG. , rotates the lower shaft 13. Further, the rotation of the lower shaft 13 is transmitted to the upper shaft by a belt 15, and a pulley 16 is fixed to this upper shaft. Although not shown, the pulley 16 is provided with a magnet R1 for detecting the thread handling stop position of the needle bar and a magnet R2 for detecting the upper stop position of the needle bar.
A Hall element R for detecting the magnets R, , R, is provided opposite to the magnets R, , R,. A tacho generator 17 that detects the speed of the sewing machine motor 11 is connected to the lower shaft 13 .

Further, the lower shaft 13 is connected to a hook 19 inside the cylindrical bed 18, and an inner hook holder 20 is provided on the outside of the hook 19 as shown in FIG. Further, a presser foot 21 is placed on the cylindrical bed 18. A needle 23 attached to a needle bar 22 is provided,
A balance 24 is provided at the top of the needle bar 22, and the needle 23
A thread tension 25 is provided at the upper left of the figure.

Further, a thread trimming motor 26 is provided within the sewing machine body, and a tachogenerator 27 that detects the speed of the thread trimming motor 26 is connected to the thread trimming motor 26. A sprocket 28 is fixed to the rotating shaft of the thread trimming motor 26.
The belt 29 that is placed on the shaft 29 is placed on an upper sprocket 30, and this sprocket 30 is fixed to a shaft 31 having a gear 32 at one end. This gear 32 is meshed with a gear 34 supported on a shaft 33, and this gear 34
has three V-shaped notches 35 on its back side as shown in Figure 3.
A thread trimming control plate 35 having numbers a, 35b and 35c is fixed. Further, one end of a rotating arm 37 is rotatably supported by a shaft 36 on the surface of the thread trimming panel 35, and the other end of the rotating arm 37 is rotatably supported by a metal 38 on the lower shaft 13. It is connected to a rotating arm 39 (see FIG. 2), forming a four-bar link mechanism.

Therefore, when the thread trimming motor 26 is rotated, the rotating arm 39 can be reciprocated. A movable knife 40 is supported by the rotating arm 39, and a fixed knife 41 is supported by the bed 18 in opposition to the movable knife 40. Therefore, when the thread cutting motor 26 is driven, the movable knife 40 is engaged with the blade of the fixed knife and cuts the thread.

Further, a signal necessary for controlling the rotation of the movable scalpel 40 is connected to the hole element 'F-' 12 attached to the bed 18.
．． 4:3 and the magnet 44.45 attached to the rotating arm 39 (
(see Figure 5). Furthermore, the thread trimming control board 3
Claw 4 that engages with ■-shaped notches 35a, 35b, and 35c of 5
6 is provided so as to be rotatable on a shaft 47, and this shaft 4
One end of a torsion spring 48 attached to 7 is hooked on a pin 49, and the other end is hooked on a claw 46. Therefore, the biasing force of the torsion spring 48 constantly presses the pawl 46 in the direction of the thread trimming control plate 35.

FIG. 4 is a block diagram of an automatic thread trimming device according to an embodiment of the present invention, in which a sewing command switch 52.
Thread trimming command switch 53. Needle position detection device 54. Needle moving knife position detection device 55. A moving knife speed detection device 56 is connected, and an upper stop position signal of the magnet R1 and a yarn handling stop position signal of the magnet R2 are input from the Hall element R to the needle position detection device 54. Furthermore, the moving knife position detection device 55 receives the moving knife origin position signal of the magnet 44 from the Hall element 42, and also receives the moving knife thread holding position detection signal of the magnet 45 from the Hall element 43. Furthermore, the moving knife speed detection device V! The output of the tacho generator 27 is input to 156 . Moreover, CPU511:ROM57. R.A.
M58 is connected. Further, the sewing machine motor 11 is connected to the CPU 51 via a sewing machine motor drive circuit 59, and the thread trimming motor 26 is connected to the CPU 51 via a thread trimming motor drive circuit 60.
is connected. In addition, a solenoid drive circuit 61 is connected to cpust, and a presser foot solenoid 62 and a thread loosening solenoid 63 are connected to this solenoid drive circuit 61.
Further, a motor 5 for feeding in the Y direction, a motor 10 for feeding in the X direction, and a sewing machine rotation motor 50 are connected to a feed drive circuit 64 connected to the CPU 51.

Next, the operation of the automatic thread trimming device of the present embodiment will be explained as follows: Fig. 5 is a diagram showing the operating state of each part, Fig. 6 is a sewing machine motion diagram and a timing explanatory diagram of thread trimming control signals, and Fig.
This will be explained with reference to the flowcharts shown in FIGS. First, when the apparatus starts (step 1), initial settings are performed (step 2), and it is determined whether there is a sewing command (step 3). When the CPU 51 reads that the sewing command switch 52 has been pressed, it lowers the presser foot 21 (step 4), then rotates the sewing machine motor 11 (step 5), and determines whether there is a sewing command (step 5). 6) When there is no more sewing command, the sewing machine motor 11 is stopped (step 7), the presser foot 21 is raised to finish the sewing operation (step 8), and the sewing machine waits for another sewing command.

Next, after the sewing command in step 3 is no longer issued, a thread trimming command is input (step 9), the presser foot 21 is lowered (step 10), and the sewing machine motor 11 is rotated (step 11), as shown in FIG. The thread handling stop position (position of the magnet R) is detected (step 12), and the sewing machine 11 is stopped (step 13). Next, the thread trimming motor 26 is rotated in the normal direction (step 14), and after confirming the detection of the thread holding position (the position where the hall element 4 detects the magnet 45) shown in FIG. 5(b) (step 15), The thread trimming motor 26 is stopped (step 16). At this position, the cut thread (upper thread or lower thread) necessary for thread cutting is captured and held in the V-shaped notch 40a of the movable knife 40.

Next, rotate the sewing machine motor 11 again in step 17).
, Upper position 1i in Figure 7! It is determined whether or not (the position of magnet R2) is detected (step 18), and when this position is detected, the sewing machine motor 11 moves the needle bar 22 to the upper stop position in FIG. 6 and is stopped ( Step 19). Next, the thread trimming motor 26 rotates forward (step 20), and the movable knife 40 is moved from the thread holding position shown in FIG. 5(b) to the position shown in FIG. 5(c).
After passing through the thread cutting position of FIG.
When the moving knife 40 detects the origin position (step 21), the thread cutting motor 26 stops and the thread cutting is completed (step 22).

However, in such a thread trimming method that is driven by a separate motor, if the sewing machine is forced to an emergency stop due to some kind of accident during sewing (including during thread trimming), or when motor 5 for Y-direction feed and X-direction feed When the sewing machine is moved by the motor 10 and the sewing machine rotating motor 50, the needle may drop and stop due to vibrations or the like.

It is also conceivable that the movable scalpel 40 stops at a location away from the predetermined origin position. In this case, it is necessary to avoid mutual collision between the needle 23 and the movable knife 40 and return them to a predetermined position. In such a case, the initial setting method shown in FIG. 8 is used. First, after the initial settings are performed (step 2), when the thread trimming motor 26 is reversed (step 23), no matter where the movable knife 40 is located, the V-shaped notch 35a of the thread trimming control board 35 The pawl 46 engages and stops at a position of ~35c. Whether the pawl 46 has stopped at any one of the V-shaped notches 35a to 35c of the thread trimming control plate 35 is determined by detecting any of the magnets 44,45 using the Hall element 42,43. If the Hall element 43 detects the magnet 44 (step 24), this indicates that the movable knife 40 has returned to its origin, so turn on the sewing machine motor 11 (step 25).
, it is determined whether the position of the magnet R2 is detected by the Hall element R (step 26), and when the magnet R8 is detected,
The sewing machine motor 11 is stopped (step 27), the thread trimming motor 26 is stopped (step 28), and the process returns between steps 2 and 3 of the flowchart in FIG. 7, and the initial setting is completed. In addition, if the magnet 45 is detected without detecting the magnet 44 in step 24 (step 29
), the sewing machine motor 11 is rotated (step 30), and it is determined whether magnet R2 is detected.Step 31), when magnet R2 is detected, the sewing machine motor 11 is stopped and the needle bar is returned to the origin first. (Step 32), then the thread trimming motor 26 is rotated in the normal direction (Step 33), and the magnet 4
In step 34), it is determined whether magnet 4 is detected.
4, the origin position of the movable knife 40 is detected, the thread trimming motor 26 is stopped (step 35), and the process returns to complete the initial setting.

As is clear from the above explanation, in the present invention, by separating the thread trimming motor from the main motor that drives the sewing machine, the main motor can be made smaller, and compared to the conventional mechanical method, Since the number of parts can be significantly reduced, there is an advantage that the entire sewing machine can be made smaller and lighter.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a sewing machine feeding device of a movable, workpiece-fixed automatic sewing system embodying the present invention, FIG. 2 is a front view of a sewing machine according to an embodiment of the present invention, and FIG. 4 is a block diagram of an automatic thread trimming device according to an embodiment of the present invention, FIG. 5 is a diagram showing the operating state of each part of the sewing machine shown in FIG. 2, and FIG. 6 is a side view as seen from arrow A. 2 is a motion diagram of the sewing machine and a timing diagram of the thread trimming control signal, FIG. 7 is a flowchart explaining the operation of the sewing machine of FIG. 2, and FIG. 8 is a flowchart explaining the initial setting of the thread trimming operation. . 1...Sewing machine, 11...Sewing machine motor, 12...
Rotation is by belt, 13...lower shaft, 14...sprocket, 15...belt, 16...pulley, 17.
...Tacho generator, 18...Bed, 19...
Hook, 20... Inner pot presser, 21... Cloth presser, 22...
・Needle bar, 23... Needle, 24... Balance, 25... Thread tension, 26... Thread trimming motor, 27... Tacho generator, 28... Sprocket, 29... Belt,
30... Sprocket, 31.33.34... Shaft,
32... Gear, 35a, 35b, 35c... V-shaped notch, 35... Thread trimming control plate, 36... Shaft, 37...
... Rotating arm, 38... Metal, 39... Rotating arm, 4
0...Moving scalpel. Applicant: Director of the Agency of Industrial Science and Technology Yukizo Iizuka Figure 2 Figure 3 Go to 40 (c) <d.

Claims (1)

[Claims] A sewing machine motor that rotates the main shaft, a needle bar position detection device that detects the thread handling position and upper stop position of the needle bar, a thread trimming motor that moves the movable knife, and detects the thread holding position and origin position of the movable knife. It consists of a moving knife position detection device,
In response to the thread trimming command, the sewing machine motor rotates, and after the needle bar position detection device detects the thread handling position of the needle, the needle is stopped at the thread handling position, and the movable knife is operated to move the needle to the movable knife position. The detection device stops the movable knife at a thread holding position where the cut thread can be caught, and then the sewing machine motor is driven, and the needle bar position detection device
An automatic thread cutting device characterized in that the needle is stopped at an upper stop position, and while the needle is stopped at the upper stop position, the movable knife is operated again to cut the cut thread.