JPH0220278B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a sewing machine, and more particularly to a threading device for passing a sewing thread through a thread hole of a sewing machine needle.

(Prior Art) Threading thread through the thread hole of a sewing machine needle is a detailed work that requires considerable attention. Conventionally, a threading bar is placed parallel to the needle bar, and a threading hook is provided at the lower end of the threading bar.The threading bar is lowered and then rotated to pass the threading hook through the thread hole of the sewing machine needle. The mechanism is in place. The operator hooks the sewing thread onto the thread hook passed through the thread hole of the sewing machine needle, rotates the threading rod in the direction in which the thread hook comes out of the thread hole and returns, and then raises the threader rod. Return to position. This allows the sewing thread to pass through the thread hole of the sewing machine needle.

The invention disclosed in Japanese Utility Model Publication No. 54-43878 disables rotation of the threading rod when the sewing machine needle is not at a predetermined position, allows rotation when the sewing machine needle is at a predetermined position, and when the threading rod descends to a predetermined position, It is then prevented from descending downwards and has a mechanism that automatically rotates the threading rod.

(Problem to be Solved by the Invention) However, the lower drive of the threading bar and the holding of the threading bar stationary at the lower position while threading the thread on the hook are coupled to the threading bar by the operator. This must be done by driving the operating rod down and holding it in the lower position. For example, drive the operating rod to the lower position with your left hand, and while holding it in the lower position,
You must use your right hand to hook the sewing thread onto the thread hook that passes through the thread hole of the sewing machine needle. Since both hands cannot be used to thread the thread, and the hook is very small, threading the thread is a tedious task that requires a great deal of attention.

The object of the present invention is to simplify and facilitate threading work.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the threading device of the present invention includes: the threading bar extending parallel to the needle bar; a sewing machine needle equipped at the lower end of the threading bar; the threading hook that can pass through the thread hole; an actuating member that drives the threading rod downward by a downward drive; the actuating member is driven up and down, and when the actuating member is driven downward, the threading hook and the sewing machine needle are a vertical drive means for holding the threading rod at a position where it matches the thread hole;
In addition to the threading mechanism, the threading mechanism includes: a rotational drive means that rotates the threading rod at the position in a direction in which the threading hook passes through the thread hole of the sewing machine needle in conjunction with the lowering of the operating member; Position detection means for detecting that the needle is in a predetermined position and generating a signal A representing this; instruction means for generating a signal B for instructing threading; and when signal B is generated when signal A is present; The apparatus further includes a vertical drive control means that biases the vertical drive means in a downward direction, and biases the vertical drive means in an upward direction when the signal B disappears.

(Function) When the threading mechanism lowers the operating member and drives the threading rod downward, the threading hook and the thread hole of the sewing machine needle are held in the same position and rotated, similar to the prior art described above. , the thread hook passes through the thread hole of the sewing machine needle, but this operation is caused by the position detecting means detecting that the sewing machine needle is in a predetermined position and generating a signal A representing this, and the indicating means detecting that the sewing machine needle is in a predetermined position. This is performed by the vertical drive control means and the vertical drive means when the signal B instructing is being generated. That is, when the operator places the sewing machine needle in a predetermined position and instructs threading with the instruction means, the operating member is automatically driven downward, the threading rod descends and rotates, and the thread hook threads the sewing machine needle. pass through the hole. The operator does not have to manually drive the actuating member down. Then, the user can hold the thread with both hands and hang the thread on the hook. Next, when the operator releases the threading instruction from the instruction means, the signal B disappears and the vertical drive control means automatically biases the vertical drive means upward, causing the operating member to rise and return to the standby position. . Therefore, when threading is required, the operator places the sewing machine needle in a predetermined position, sets the indicating means to the threading instruction state, automatically responds to this, and hooks the thread to the thread hook passing through the thread hole. All that is required is to return the instruction means to the returned state. You can use both hands to hang the thread on the thread hook.

For example, it becomes possible to automatically pass the thread to the hook using an air stream and perform threading fully automatically.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

(Embodiment) Fig. 1a shows the mechanism of the sewing machine arm in an embodiment of the present invention, and Fig. 1b shows the mechanism of the sewing machine arm section shown in Fig. 1a.
A cross section taken along line B is shown. Referring to these drawings, the needle bar 5 is guided by the needle bar support frame 2 so as to be movable in the vertical direction. The needle bar support frame 2 is fixed to the sewing machine frame 1 with pins 3 and set screws 4. A thread hook 6 is fixed to the lower end of the needle bar 5, and a needle 8 is fixed by a screw 7. The needle bar holder 9 is attached to the needle bar 5 with a screw 10, and the needle bar 5 is attached to the upper shaft 40 (FIG. 1c) via the needle bar holder 9 and a known needle bar crank rod (not shown), needle bar crank, and thread take-up crank. The upper shaft 40 moves up and down as the upper shaft 40 rotates. The needle bar guide 11 is connected to the needle bar 5 by a screw 12.
The arm portion 11a is attached to the needle bar support frame 2 with a screw 1.
The needle bar 5 is inserted into the groove 13a of the guide plate 13 fixed by the guide plate 4, and prevents the needle bar 5 from rotating. The threading rod 15 is supported in parallel with the needle bar 5 by shaft bearings 2a and 2b provided on the needle bar support frame 2, and a shaft cylinder 16 is press-fitted into the lower end thereof and is prevented from rotating by a pin 17. A threading hook 20 is fixed in the groove 16a (FIG. 3d) of the barrel 16 between a pair of guide pieces 18 and 19 with a fastener 21. Hook 20 (Fig. 3d,
Fig. 3e) is formed so that when the threading rod 15 is rotated when vertically aligned with the thread hole 8a of the needle 8, it enters the thread hole 8a (Fig. 3e). The operating rod 22 for driving the threading rod 15 vertically and rotationally has an upper bent portion 22a and a lower bent portion 2.
2b, and a threading rod 15 passes through these bent portions. An inclined slot 22c (Fig. 3a) is provided in the upper part of the operating rod 22, and an operating pin 23, which is implanted at the upper end of the threading rod 15 and has both ends protruding horizontally, is fitted into this slot 22c. are doing. Furthermore, a spring hook 22D and an arm portion 22E (FIG. 1a) are provided at the center of the operating rod 22. Furthermore, the operating rod 22 has a side surface 22F (third
(Fig. c) and the side surfaces 2c of the shaft bearings 2a and 2b of the needle bar support frame 2. The tension spring 24 is tensioned between the spring hook 22D and a screw 25 fixed to the needle bar support frame 2, and normally pulls the operating rod 22 upward. When the lower bent portion 22b of the operating rod 22 hits the needle bar support frame 2, the operating rod 22
The upward movement of stops. Figures 1a and 1b illustrate this situation. In this state, the operating rod 22
The pin 23 is pushed down by the repulsive force of the compression spring 26 inserted between the upper bent part 22a and the pin 23, and the pin 23 hits the lower end of the slot 22c. Along with being at the upper limit position, it is also at the upper limit position.

One end of a wire 30 is fixed to the arm 22E of the operating rod 22, and the wire 30 is stretched downward and hung on a pulley 27B, and stretched upward and hung on a pulley 27A, with the other end attached to the piston rod. It is fixed to the hanger 31a at one end of 31b.

The pulleys 27A, 27B have stepped pins 28A, 2
8B, and is loosely fitted in the E ring 29A, 2 so that it can rotate freely.
It is prevented from coming off by 9B. Stepped pin 28
A and 28B are fixed to the upper and lower parts of the needle bar support frame 2 so that the pulleys 27A and 27B are on the same plane.

A piston is fixed to the other end of the piston rod 31b within the air cylinder 31,
This piston divides the space inside the air cylinder 31 into two left and right. The left ventricle has the first port 31c.
is in communication with the right ventricle, and a second port 31d is in communication with the right ventricle.

The air cylinder 31 is fixed to the sewing machine arm 1 with a bracket 32 and screws 33.

As shown in FIG. 1c, the air cylinder 31 is connected to an electromagnetic switching valve 46b, and when the electric coil of the electromagnetic switching valve 46b is de-energized, an air source 46c (in this embodiment, driven by an electric motor) is connected to the air cylinder 31. The first port 31c of the air cylinder 31 communicates with the high pressure output port of the air pump (air pump), and the second port 31d communicates with the low pressure output port (intake port or atmospheric pressure port), and in this state, the wire 30 communicates with the tension spring 24. and the piston rod 31b is pushed out to the rightmost end (No. 1a).
Figure 1b).

When the electric coil of the electromagnetic switching valve 46b is energized, the first port 31c of the air cylinder 31 communicates with the low pressure output port of the air source 46c, the second port 31b communicates with the high pressure output port, and the piston rod 31b is driven to the left. be done. This causes the spring 24
The wire 30 resists the tensile force of the piston rod 3
1b, the operating rod 22 moves downward, and the threading rod 15 descends with the pin 23 in contact with the lower end of the slot 22c. Then, when the pin 23 collides with the upper surface 11c of the notch in the needle bar guide 11, the threading bar 15 is prevented from descending. Due to the further lowering of the operating rod 22, and due to the fact that the operating rod 22 is prevented from rotating and the slot 22c is inclined, the pin 23 (i.e., the threading rod 15) is
In Fig. 3c, rotational force is applied in the clockwise direction. The needle bar guide 11 has a ring-shaped horizontal groove 11b continuous with the upper surface 11c of the notch, and the pin 23 enters into this horizontal groove 11b and rotates. When rotated in this way, the pin 23 finally moves into the slot 22c.
Since it is engaged with the uppermost end of the lateral groove 11b and the horizontal groove 11b, the lowering of the operating rod 22 is also stopped. Figure 2a shows the state in which the operating rod 22 has also stopped descending.
This is shown in Figures 2b and 3b.

In this state, the guide pieces 18, 19 and the hook 20 between them, which were in the position shown by the two-dot chain line in Fig. 3d, have rotated to the position shown by the solid line in Fig. 3d, and the hook 20 As shown in Figure 3e, it passes through the thread hole 8a of the sewing machine needle 8. In this state, the operator touches the lower edges of the guide pieces 18, 19 and the hook 2.
0, insert a thread pulled in a straight line toward the sewing machine needle 8 in a direction perpendicular to the sewing machine needle 8. Alternatively, in the fully automatic threading mode, sewing thread is blown out in a straight line between the rear edge of the curved end of the hook 20 and the sewing machine needle 8 using an air jet.

When the electric coil of the electromagnetic switching valve 46b is de-energized, the piston rod 31b moves to the air cylinder 31.
The actuating rod 22 moves upward due to the tensile force of the spring 24. At the beginning of this movement, the pin 23 is in the horizontal groove 11b and is prevented from moving upward, so only the operating rod 22 rises, and since the slot 22c is inclined, the pin 23 moves counterclockwise (Fig. 3c). is applied, the pin 23 rotates counterclockwise, and the horizontal groove 11b
As a result, the hook 20 rotates in the return direction from the thread hole 8a and returns to the position shown by the two-dot chain line in FIG. The pin 23 (that is, the threading rod 15) moves up together with the operating rod 22 through the thread hole 8a.

Referring again to Figure 1c. A slit plate 42 is fixed to the upper shaft 40, and this slit plate 4
A slit is cut in 2, and the sewing machine needle 8
The most suitable predetermined position for threading (the hook 2 when the threading rod 15 is lowered as shown in Fig. 2b)
A photo sensor (light emitting element + photo transistor) 4 is arranged to detect the slit when the thread hole 8a of the sewing machine needle 8 is at a height of 0.
3 is equipped. The photo sensor 43 provides a low-level slit detection signal to the signal processing circuit 44 while detecting a slit. The signal processing circuit 44 is composed of an energizing circuit that causes the light emitting element of the photo sensor 43 to emit a constant amount of light, and a binarization circuit that amplifies the detection signal of the photo transistor, shapes the waveform, and converts it into a binary value. The AND gate 45 of the controller 45 outputs the needle position detection signal A which is at a high level H when the slit is being detected and is at a low level L when the slit is not detected.
Give to c.

The operation board of the sewing machine is equipped with a threading instruction switch 47. When it is open, the inverter 45a generates a low level L, and when it is closed, it generates a high level H threading instruction signal, which is sent to the OR gate. It is applied to AND gate 45c through 45b. Note that another signal line is connected to the OR gate 45c so that it can be applied to fully automatic threading, and a threading instruction signal (high level ) is applied.

When the sewing machine needle 8 is in a predetermined position, the signal processing circuit 44 generates the needle position detection signal A of high level H, and at this time the switch 47 is closed or the other signal line When becomes high level H, OR gate 45b generates threading instruction signal B (high level H) and AND gate 4
5c becomes a high level H, and in response, the solenoid driver 46a energizes the electric coil of the electromagnetic switching valve 46b. Then air cylinder 3
1, the first port 31c becomes low pressure, the second port 31d becomes high pressure, the operating rod 22 descends, and the third port 31c becomes low pressure.
As shown in Figure e, the hook 20 passes through the thread hole 8a of the sewing machine needle 8. At this time, the operating rod 22 and the threading rod 15 are in the positions shown in FIGS. 2a and 2b.

The operator tensions the sewing thread in a direction perpendicular to the needle 8 and inserts it between the lower edges of the guide pieces 18, 19 and the upper edge of the hook 20 from the left side to the right side as shown in FIG. 3e. Alternatively, in a fully automatic threading mode, the thread is passed through the air jet into the space between the hook 20 and the needle 8a, and between the lower edge of the guide pieces 18, 19 and the upper edge of the hook base. . When the switch 47 is returned to open or when the signal on the other signal line becomes low level L, the OR gate 45b
The output of returns to low level L, and the AND gate 45c
The output returns to low level L, and the hook 20 returns to the thread hole 8.
The thread that has come out in the original direction from a and caught on the hook of the hook 20 at this time passes through the thread hole 8a. Operating rod 2
2 and threading rod 15 as shown in FIGS. 1a and 1b.
Return to the position shown.

When the sewing machine needle 8 is not at the predetermined position, the output of the circuit 44 is at a low level L.
Even if the output of the OR gate 45b becomes a high level H (threading instruction), the output of the AND gate 45c remains at a low level L and does not change, and the solenoid driver 46a does not energize the electric coil of the electromagnetic switching valve 46b. That is, the actuating rod 22 and the threading rod 15 are in the positions shown in FIGS. 1a and 1b, neither lowering nor rotating the threading rod 15. Therefore, the hook 20 will not collide with the needle 8 and be damaged.

Next, other embodiments or modified examples will be described. In the embodiment described above, the air cylinder 31, the wire 30, and the tension spring 24 are used as means for driving the threading rod 15 up and down. In another embodiment of the invention, the vertical drive means is a linear motor. For example, the linear motor disclosed in Japanese Patent Application Laid-open No. 164249/1984 or other known linear motors may be used. Further, the air cylinder 31 may be replaced with a motor and a wire take-up reel, or may be replaced with a solenoid device.

If the air cylinder 31 is used as in the above embodiment, an air source 46c is required as shown in FIG. 1c, and the number of mechanical elements increases. This is because an air source is required to feed the sewing thread, such as by sending out the thread with an air jet, so the air source for this purpose is also used to drive the threading rod 15. In a sewing machine that only has the function of driving the threading rod 15 vertically and rotationally, the vertical driving means may be a linear motor, an electric motor + wire take-up reel, or a solenoid device, as described above.
It is preferable to use an electric mechanism that directly converts current into mechanical power in order to reduce the number of mechanical elements.

〔Effect of the invention〕

As described above, the threading device of the present invention automatically threads the hook through the thread hole of the sewing machine needle in response to an instruction from a switch or the like. This can be done with an automatic thread feeder. When the worker performs the work with both hands, he or she can concentrate on the work, making it easier to work reliably. In conventional devices, in order to prevent the hook from being damaged due to erroneous operation outside the threading range, a stopper was attached to the needle bar support frame to prevent malfunction, making the parts around the needle bar complicated. However, in the threading device of the present invention, since the needle position is electrically detected to determine whether or not the hook can be operated, malfunction of the hook can be prevented without complicating the parts around the needle bar. For example, industrial sewing machines are already equipped with a position detector that electrically detects the needle position, so this can be commonly used for threading control. In addition, it can be directly combined with an automatic feeding device that supplies thread to the hook portion using an air jet, and fully automatic threading in which hook driving and threading are all performed automatically is possible.

[Brief explanation of drawings]

FIG. 1a is a partially cutaway side view of a sewing machine arm according to an embodiment of the present invention, and FIG.
The figure is a sectional view taken along the line B--B in FIG. 1a. These drawings show the threading rod 15 in a standby position. FIG. 1c is a block diagram showing the configuration of a control system that controls air supply to the air cylinder 31 shown in FIG. 1a. Similar to FIG. 1a, FIG. 2a is a partially cutaway side view of the sewing machine arm, and FIG. 2b is a side view taken along the line B-B in FIG. 2a.
FIG. These drawings show the threading rod 15
Indicates that the is in the threading position. FIG. 3a is an enlarged rear view of a portion of the operating rod 22 shown in FIG. 1b. FIG. 3b is an enlarged cross-sectional view of a part of FIG. 1b. FIG. 3c is a sectional view taken along the line CC in FIG. 3b. Figure 3d is a sectional view taken along the line DD in Figure 2b. Third
Figure e is an enlarged perspective view of the guide pieces 18 and 19 shown in Figure 2b. 1: Sewing machine arm, 2: Needle bar support frame, 3A, 3
B: Pin, 4A, 4B: Set screw, 5: Needle bar (needle bar), 6: Thread hook, 7: Screw, 8: Sewing machine needle (sewing machine needle), 8a: Thread hole (thread hole), 9: Needle Holding a stick,
10: Screw, 11: Needle bar guide, 11b: Horizontal groove, 1
1c: Top surface of notch, 12: Screw, 13: Needle guide, 14: Screw, 15: Threading bar (threading bar),
16: shaft cylinder, 17: pin, 18, 19: guide piece,
20: Threading hook (threading hook), 21:
Fastener, 22: operating rod (operating member), 22c: inclined slot, 22D: spring hook, 22E: arm,
23: Pin, 24: Spring, 25: Screw, 26: Spring, 27A, 27B: Pulley (23, 22c, 2
6, 11c, 11b: rotational drive means), 28A,
28B: Stepped pin, 29A, 29B: E ring,
30: wire, 31: air cylinder, 31b:
Piston rod, 31c: 1st port, 31d:
2nd port (24, 27A, 27B, 30, 3
1: Vertical drive means), 32: Bracket, 33:
Screw, 37: Sewing machine motor, 38: Clutch & brake, 39: Connection mechanism, 40: Upper shaft, 41: Lower shaft, 42: Slit plate, 43: Photo sensor, 4
4: signal processing circuit (42, 43, 44: position detection means), 45: controller, 46: air cylinder driver (46, 45: vertical drive control means), 47: threading instruction switch (instruction means).

Claims (1)

[Scope of Claims] 1. A sewing machine equipped with a vertically movable threading rod that is disposed in a sewing machine arm and allows a thread hook to be detached from around the sewing machine needle when not in use and arranged around the sewing machine needle when in use. In the threading device, the threading bar extends parallel to the needle bar; the threading hook is provided at the lower end of the threading bar and is capable of passing through the thread hole of the sewing machine needle; the threading bar is driven downward. an operating member that drives the operating member downward; vertical driving means that drives the operating member up and down and holds the threading rod at a position where the threading hook and the thread hole of the sewing machine needle match when the operating member is driven downward; a rotational driving means for rotationally driving the threading rod at the position in a direction in which the thread hook passes through the thread hole of the sewing machine needle in conjunction with the lowering of the operating member; detecting that the sewing machine needle is at a predetermined position; position detecting means for generating a signal A representing this; instructing means for generating a signal B for instructing threading; and, when signal B is generated while signal A is present, the vertical driving means is urged to be driven downward. A threading device for a sewing machine, comprising: a vertical drive control means that urges the vertical drive means upward when the signal B disappears. 2. The vertical driving means includes a tension coil spring that drives the actuating member upward, a string whose one end is fixed to the actuating member, and a part of the string near the one end guided downward and a part away from the part. The up-and-down activation control means consists of a pulley that guides upward, and an air cylinder that has a piston rod connected to the other end that connects to the remote part. An electromagnetic switching valve that switches and supplies electricity, an energizing circuit that energizes and energizes the electromagnetic switching valve, and when signal B occurs when signal A is present, it instructs the energizing circuit to energize, and when signal B disappears, the energization is cut off. A threading device for a sewing machine according to claim 1, comprising an energization control means for instructing.