JPS63105790A - Yarn passage controllable sewing machine - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sewing machine capable of controlling thread passage, and particularly to a thread take-up body (
A pair of thread engaging bodies for respectively passing and prohibiting the upper thread from passing at predetermined timings in a thread supply path leading to a thread take-up thread, and a thread passing control means for controlling the thread engaging members are provided, and at least one of passing the thread and inhibiting the passing of the thread is provided. is made to be proportional to the rotational speed of the main shaft of the sewing machine.

(Prior art) In general, a thread take-up that moves up and down in synchronization with the main shaft of a sewing machine is
When descending, the upper thread for sewing with the sewing needle is supplied to the lower thread bobbin side, and when ascending, the upper thread loop formed in the eye of the sewing needle is tightened during the sewing process, and the upper thread is supplied to the lower thread bobbin for sewing the next stitch. It plays the role of replenishing a predetermined amount of thread from the thread spool.

Preferably, a thread tension device is provided in the thread supply path from the thread spool to the thread holding portion of the thread take-up thread to provide passage resistance to the needle thread in order to enable tightening of the needle thread loop. be. This thread tension device has a mechanism in which a pair of thread tension discs are brought into pressure contact with each other by a compression spring, and frictional resistance is applied to the upper thread passing between the pair of thread tension discs.

However, with this type of thread tension device, the upper thread is supplied based on the interaction between the tension acting on the needle thread after the thread tension device and the resistance force at the thread tension device, so the tightening force of the needle thread It is difficult to accurately control the supply amount of fabric, and the thickness and type of fabric (
In other words, it is difficult to control the thread tension of the stitches in accordance with the thickness and type of the upper thread that are selected accordingly.

Therefore, in recent years, for example, as described in Japanese Patent Publication No. 53-41580, instead of the spring-type thread tension device, a pair of thread tension discs are brought into pressure contact with each other by a solenoid-type actuator. An electric thread passage control device that allows the passage of the upper thread for a prescribed period at a prescribed timing by driving an actuator in synchronization with the rotation of the needle, and prohibits the passage of the upper thread at other times. is proposed.

(Problem to be Solved by the Invention) In the thread passage control device described in the above publication, thread passage is controlled in synchronization with the main shaft of the sewing machine, regardless of the thickness or type of work cloth, that is, the thickness of the needle thread. Moreover, the operating speed when releasing the thread passage and the operating speed when restricting the thread passage are set independently of the rotational speed (sewing speed) of the main shaft of the sewing machine.

Therefore, the upper thread is tightened uniformly for both thick and thin upper threads, and the upper thread is uniformly supplied, so that the tension is adjusted according to the thickness of the upper thread. The upper thread cannot be tightened, and the thread tension of the stitch becomes unstable.

Furthermore, as the rotational speed of the main shaft of the sewing machine changes, the amount of needle thread supplied also changes slightly, so the thread tension also changes depending on the sewing speed.

(Object of the Invention) An object of the present invention is to provide a sewing machine capable of controlling thread passage so that tightening tension can be obtained according to the thickness of the needle thread, and the thread tension can be stabilized even when the sewing speed changes.

(Means for Solving the Problems) A sewing machine capable of controlling thread passage according to the present invention has a thread supply path that extends from a thread supply source to an eye of a sewing needle via a thread take-up body, and a thread supply path that connects the thread supply source to the thread. A pair of thread engaging bodies that are movable relative to each other in order to permit and prohibit passage of the sewing thread in the thread supply path between the pick-up body and a thread passing unit that controls the approach and separation of both thread engaging bodies. In a sewing machine equipped with a control device, a speed proportional means operatively connected to the main shaft of the sewing machine is configured to control the thread passage so that the speed of at least one of the approaching and separating operations of the two thread engaging bodies is proportional to the rotational speed of the main shaft of the sewing machine. It is installed in the device.

If necessary, the speed proportional means may include a cam body which is operatively connected to the main shaft of the sewing machine and has an elliptical cam surface, and the thread passage control device may control the thread engaging body according to the cam surface of the cam body. The approach and separation of the objects may be controlled.

If necessary, the speed proportional means may include a rotating body operably connected to the main shaft of the sewing machine, and a detector that detects rotation of the rotating body by a predetermined unit angle and generates rotation pulses. The yarn passage control device may change the relative position of both yarn engaging bodies during at least one of the approaching and separating operations of both yarn engaging bodies in synchronization with the rotation pulse.

(Function) In the sewing machine capable of controlling thread passage according to the present invention, there is a relative movement in the thread supply path between the thread supply source and the thread take-up body among the thread supply paths leading from the thread supply source to the eye of the sewing needle. A pair of possible thread engaging bodies are interposed, and the thread engaging bodies allow and prohibit passage of the suture thread. This one is controlled by the thread passage control means.
The pair of thread engaging bodies are controlled, and when the thread engaging bodies approach, passage of the suture is prohibited, and when the thread engaging bodies are separated, passage of the suture is permitted.

The thread passage control device is provided with a speed proportional means operatively connected to the main shaft of the sewing machine, so that the operating speed of at least one of the approach and separation of the two thread engaging bodies is proportional to the rotational speed of the main shaft of the sewing machine. .

As a result, even if the rotational speed of the main shaft of the sewing machine changes, the thread tension of the stitches hardly changes.

Particularly, when the speed proportional means is constituted by a cam body which is operatively connected to the main shaft of the sewing machine and has an oval cam surface, and the thread passage control device controls the approach and separation of both thread engaging bodies according to the cam surface of the cam body. In this case, the movement of the two thread engaging bodies toward and away from each other is performed continuously and smoothly at a speed proportional to the rotational speed of the main shaft. Therefore, in this case, the timing of thread restraint and thread release changes depending on the thickness of the sewing thread. In other words, thick sewing threads are restrained earlier and released later than thin sewing threads, so thick sewing threads require less thread supply and are tightened strongly, while thin sewing threads require more thread supply. It will be weakly tightened. In this way, the thread tension becomes stable depending on the thickness of the sewing thread and the rotational speed of the main shaft.

(Effects of the Invention) According to the sewing machine capable of controlling thread passage according to the present invention, as described above, the relatively simple configuration consisting of a pair of thread engaging bodies and a thread passage control device that controls the thread engaging bodies allows As the thickness of the sewing thread increases, the amount of thread supplied is reduced to strengthen the tightening force, thereby making it possible to obtain a thread tension suitable for the thickness of the sewing thread.

Furthermore, by making the operating speed of the thread passage control proportional to the rotational speed of the main shaft of the sewing machine, stable thread tension can be achieved regardless of the sewing speed.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an electronically controlled lockstitch sewing machine to which the present invention has been applied. An arm portion 6 extending leftward from the upper end is disposed horizontally so as to face above the bed portion 2, and a head portion 8 is provided at the left end portion of the arm portion 6. A needle bar 10 and a presser bar 18 are attached to the head 8, and the needle bar 10 and the sewing needle 12 at its lower end are attached to the head 8.
As will be described later, the sewing machine is driven vertically by the main shaft 28 of the sewing machine, and is auxiliary driven left and right by a friction mechanism (not shown). The presser foot 18 and the presser foot 20 at its lower end are raised and lowered by operating an operating body not shown.

The bed section 2 is provided with a needle plate 22 and a feed dog 23 that passes through the needle plate 22 and appears on the top surface of the bed section 2. A predetermined seam will be formed in the cloth. The cloth feeding mechanism is similar to an existing general structure, so a detailed explanation will be omitted.

2 to 4 show the internal mechanism provided in the head 8 of the sewing machine M and the arm portion 6 in the vicinity thereof.

As shown in the figure, a sewing needle 12 is attached to the lower end of the needle bar 10, and the needle bar 10 is attached to a needle bar support 24 so as to be movable up and down. As a result, the needle bar 10 is movable left and right about the pin 26 together with the needle bar support 24, and the needle bar 10 is pivotally connected to the main shaft 28 and the end of the main shaft 28 with respect to the needle bar support 24. It is designed to be driven up and down by a needle bar crank 30 in the section.

A presser foot 20 is removably attached to the lower end of the presser bar 18, and the presser bar 18 is attached to the machine frame by a mechanism not shown, and is switched between a raised position and a lowered position. When in the lowered position, the presser foot 20 presses the work cloth against the throat plate 22.

Next, the balance mechanism will be explained with reference to FIGS. 2 to 4.

The main shaft 28 of the sewing machine is rotatably attached to the machine frame via a bushing metal 32, etc., and a sub-shaft 34 is disposed diagonally above and behind the main shaft 28 in parallel with the main shaft 28. It is rotatably attached to the frame. This secondary shaft 34
One end of a swing lever 36 is rotatably connected to the lever 36, and the friction lever 36 extends from the subshaft 34 to the left end side of a balance crank 38 fixed to the main shaft 28. Elongated cam hole 42 of swing lever 36
A connecting plate 44 is fixed to the left end of the crank pin 40 on the left side of the swing lever 36, and the needle bar crank 30 is attached to a pivot pin 46 extending leftward from the connecting plate 44. The lower end portion of the needle bar crank 30 is connected to the middle portion of the needle bar 10.

At the upper end of the front part of the swing lever 36, a thread take-up lever 48 (thread take-up body) that extends upward in a crank shape is formed inside.
A thread holding portion 48a is formed at the upper end of the thread take-up 48.

The cam hole 42 of the swing lever 36 allows the crank pin 40, which is located near the uppermost position and has the same radius as the rotation locus of the crank pin 40, to rotate approximately 74 degrees as shown in FIGS. 2 and 3. It is formed of an arcuate hole 42a and a short straight hole 42b extending straight from both ends of the arcuate hole 42a, and the outer periphery of this cam hole 42 is reinforced with a reinforcing portion 36a.

A crank pin 40 is inserted into the cam hole 42 of the FSS dynamic bar 6.
is inserted into the balance crank 38 and crank pin 4.
0 rotates around the main shaft 28, the +g movement lever 36 is rotated by the crank pin 40 around the sub shaft 34 as the third
It is reciprocally driven up and down between the top position shown by solid lines and the bottom position shown by imaginary lines in the figure. At this time, the needle bar 10 is reciprocated up and down via the needle bar crank 30 and crank pin 40 in synchronization with the rotational movement of the sewing machine main shaft 28.

Since the circular arc hole 42a as described above is formed in a part of the cam hole 42 of the swing lever 36, the movement of the balance 48 using the rotational phase angle of the main shaft 28 as a parameter is as shown by the curve MA in FIG. The movement of the sewing needle 12 attached to the lower end of the needle bar 10 is as shown by the curve MB in FIG.
become that way.

The thread take-up 48 is held at the uppermost position from when the main shaft 28 rotates approximately 40 degrees after the start of cloth feeding until the eye of the sewing needle 12 reaches the upper surface of the throat plate 22. Therefore, the thread take-up 48 is held at the uppermost position during the period when cloth feeding is substantially carried out, except at the initial stage of cloth feeding. However, the swing lever 36 may be configured so that the thread take-up lever 48 is located at the uppermost position from the start of cloth feeding. In any case, the structure of the swing lever 36 in this embodiment is relatively simple and operates smoothly and quietly.

Next, the yarn passage control mechanism will be explained with reference to FIGS. 2 to 7.

Immediately to the left of the needle bar crank 30 at the left end of the main shaft 28, a plate member 50, which is a part of the machine frame, is provided perpendicularly to the main shaft 28. As shown in FIGS. 2 and 3, a needle thread 14 is attached to the left side of the plate member 50 at a position slightly forward of the main shaft 28.
A britension device 52 that can provide passage resistance is provided as necessary.

This britension device 52 allows the upper thread to pass between a pair of thread tension discs 52a, and by rotating a dial, the spring force can be adjusted to adjust the thread passing resistance. This britension device 52 may be omitted.

Furthermore, the movement of the main shaft 28 moves the needle thread 14 from the thread spool 16 to the thread holding portion 48a of the thread take-up lever 48 in the needle thread supply path that extends from the thread spool 16 to the thread holding portion 48a of the thread take-up lever 48 to the eye of the sewing needle 12. A movable plate 58 having a pair of yarn path regulating plates 56 and a movable ring 64 as a pair of yarn engagement/bodies, and their approach/separation are controlled so that the yarn can be restrained or released at the same time. A yarn passage control device 54 is provided as follows.

A thread path regulating plate 56 (thread engaging body) is fixed to the left side of the plate member 50 at a position below the britension device 52, and is linked with a movable plate 58 disposed near the left side of the thread path regulating plate 56. The lower end of the arm 60 is rotatably attached to the plate member 50 by a stepped screw 62, and the movable ring 64 (thread engagement body) of the movable plate 58 abuts the regulating portion 56a of the thread path regulating plate 56 from below. The upper thread 14 is arranged between the regulating part 56a and the movable ring 64 in contact with each other so that the upper thread 14 can be held and restrained, and one end of the movable plate 58 is attached to the machine frame so that the movable ring 64 is pressed against the regulating part 56a. Elastically biased by a fixed spring 66, a contact shaft 68 at the upper end of the arm portion 58a of the movable plate 5 contacts the contact portion 60a near the lower end of the link arm 60 from the front.

As shown in FIG. 2, FIG. 3, and FIG. The regulating portion 56a is formed in an inverted U shape when viewed from the side so as to be engaged with the groove 64a from above, and the regulating portion 56a is formed in a real screen shape with a U-shaped cross section.

The needle thread 14 that has passed through the britension device 52 is bent into a U-shape at the regulating portion 56a of the thread path regulating plate 56, and extends to the sewing needle 12 via the thread holding portion 48a of the thread take-up lever 48.

The needle thread 14 bent by the regulating portion 56a is held between the regulating portion 56a and the V-groove 64a at two points and is strongly restrained. In particular, the movable ring 6 moves in a direction parallel to the plane including the thread supply path of the needle thread 14 bent at the regulating portion 56a.
4 is driven and clamps and restrains the upper thread 14 in a transverse manner.
The surface pressure that clamps the needle thread 14 becomes extremely large. In other words, even when the force pressing the movable ring 64 is small, the needle thread 14 can be strongly restrained.

Then, in synchronization with the rotation of the main shaft 28, the movable ring 64 of the movable plate 58 is driven up and down at an operating speed proportional to the rotational speed of the sewing machine main shaft 28, thereby releasing and restraining the upper thread 14 at predetermined timing. Therefore, a rotary cam 70 (speed proportional means) having an elliptical cam groove 72 is fixed to the main shaft 28 at a position corresponding to the right end side portion of the subshaft 34, and the first arm 74 fixed to the subshaft 34 is A contact 74a at the tip engages with the cam groove 72.

On the other hand, a second arm 76 is fixed to the left end of the subshaft 34, and the lower end of the second arm 76 is connected by fitting a pin 76a into a loose bottle hole 60b at the upper end of the link arm 60.

In the above yarn passage control device 54, the rotary cam 70 rotates together with the main shaft 28, and the first
When the arm 74 swings, the second arm 7
6 swings, and when the second arm 76 moves by 1g, the link arm 60 swings around the stepped screw 62.

As a result, the contact shaft 68 at the contact portion 60a of the link arm 60
When is pushed forward, the movable plate 5 rotates against the spring force, the movable ring 64 separates from the regulating portion 56a of the thread path regulating plate 56, and the upper thread 14 is released from the restrained state. . Further, when the contact portion 60a of the link arm 60 moves rearward, the movable plate 58 rotates by the elastic force of the spring 660, and the movable ring 64 moves to the restricting portion 5.
6a, and the needle thread 14 is held and restrained between the regulating portion 56a and the movable ring 64. In this way, the upper thread 14 is released and restrained at predetermined timings. The timing at which the needle thread 14 is released or restrained in this manner is shown by the curve MC in FIG.

As can be seen from FIG. 5, when the needle thread 14 is tightened as the thread take-up lever 48 rises from the lowest position to the highest position, the needle thread 14 is restrained by the thread path regulating plate 56 and the movable ring 64, so that the needle thread is tightened. 14 tightening is performed reliably. balance 48
When the needle thread 14 reaches the uppermost position and tightening of the needle thread 14 is completed, the needle thread 14 is supplied in conjunction with the cloth feed, so that the restriction by the thread path regulating plate 56 and the movable ring 64 is released, and the required amount of needle thread 14 is delivered to the thread. It is supplied from the piece 16 to the balance 48.

Cloth feeding and needle swinging are completed with the upper thread 14 unrestricted, and by the time the sewing needle 12 reaches the throat plate 22, the upper thread 14 is restrained again. In this state, the sewing operation is performed and an upper thread loop is formed on the lower thread bobbin side. Therefore, the required amount of needle thread 14 consumed for cloth feeding and needle swinging is reliably supplied, and since the needle thread 14 is restrained when forming the needle thread loop, unnecessary needle thread 14 is not supplied.

As shown in the curve MC in FIG. 5, from the restraining characteristics determined by the elliptical shape of the cam groove 72 of the rotating cam 70, in the case of the thin needle thread 14, it is released at the point F and also at the point C1.
In contrast, in the case of thick upper thread 14, it is released at point F2, which is later than point F1, and is restrained at point C1.
It is constrained at point C2, which is earlier than . Therefore, when the needle thread 14 is thin, the needle thread 14 is tightened with an appropriate weak tension, and when the needle thread 14 is thick, the needle thread 14 is tightened with a suitably strong tension.

Since the cam groove 72 of the rotary cam 70 as the speed proportional means is formed in an elliptical shape, the swing speed when the first arm 74 swings upward and when the first arm 74 swings downward can be reduced. The swing speed of is proportional to the rotation speed of the main shaft 28,
The movable ring 64 approaches and moves away from the regulating portion 56a at a speed proportional to the rotational speed of the main shaft 28.

As a result, even if the rotational speed of the main shaft 28 changes in magnitude, the supply amount of the needle thread 14 is maintained substantially constant, so that the thread tension of the stitches does not vary depending on the sewing speed.

Next, while the thread take-up lever 48 is swinging downward and the upper thread 14 is being restrained by the movable ring 64 and the thread path regulating plate 56, the thread spool 16 is
The thread pay-out mechanism 78 that pays out and stores a predetermined amount of needle thread 14 will be described with reference to FIGS. 2 to 4.

A sleeve 80 is rotatably fitted onto a portion of the subshaft 34 that supports one end of the swing lever 36, and one end of the swing lever 36 is fixed to the sleeve 80. This sleeve 80 has an actuation arm 82 that is crank-shaped when viewed from the side.
is fixed to the actuating arm 82, and a hook-shaped thread catching portion 82a is formed at the tip of the actuating arm 82. A gate-shaped thread guide body 84 is disposed at the upper end of the left end of the arm part 6 of the sewing machine M, and the thread guide body 84 extends from the upper plate part 84a and the right and left ends of the upper plate part 84a, respectively. First guide plate 84b extending vertically downward
and a second guide plate 84c.
The thread guide body 84 is attached to the machine frame by fixing the guide plate 84c to the upper end of the plate member 50 with screws 86, and the thread guide body 84 is disposed near the top of the operating arm 82. The first guide plate 84b and the second guide plate 84C face each other with a predetermined distance apart in the left-right direction, and the first guide plate 84b and the second guide plate 84C have a first guide groove 88a and a second guide groove, respectively. 88b are formed to face each other laterally, and these first and second guides! The rear ends of 88a and 88b are open for introducing the upper thread 14. Furthermore, a third guide groove 90 notched from above is provided at the front end of the second guide plate 84c on the left side.
is formed.

The upper thread 14 extending from the thread spool 16 is connected to the first guide groove 88a and the second guide groove 88a.
from the left side of the second guide plate 84c through the guide groove 88b.
The yarn is introduced into the guide groove 90 in a bent manner, and is passed from the third guide groove 90 through the britension device 52 and between the yarn path regulating plate 56 and the movable ring 64 at the bent portion of the regulating portion 56a of the yarn path regulating plate 56. It is bent upward, and extends from the bent portion to a thread holding portion 48a at the tip of the thread take-up lever 48, and from the thread holding portion 48a to the eye of the sewing needle 12 via thread guide portions 92 and 94.

Both the actuation arm 82 and the swing lever 36 are attached to the sleeve 3.
0, and are driven to swing in synchronization with the rotation of the main shaft 28 via the balance crank 38, but the opening actuating arm 82 has the balance 48 in the uppermost position as shown by the solid line in FIG.
are the first and second guide grooves 88a and 88 as shown by dotted lines.
When the swing lever 36 swings about the counter shaft 34 when the thread take-up 48 descends to the lowest position as shown by the imaginary line, the operating arm 82 also moves forward about the secondary shaft 34 as shown in the imaginary line, and the thread catcher 82 at the tip of the operating arm 82
a moves forward so as to intersect the upper thread 14 extending between the front ends of the first and second guide grooves 88a and 88b. At this time, the needle thread 14 is let out a predetermined distance forward by the thread catching portion 82a of the operating arm 82. During this delivery,
Since the needle thread 14 is restrained by the thread path regulating plate 56 and the movable ring 64, a predetermined amount of the needle thread is reliably let out from the thread spool 16.

In this way, while the thread take-up lever 48 is at the lowest position, the upper thread I4 is let out by the operating arm 82 of the thread let-out mechanism 78, and the thread path regulating plate 56 is bent from the thread let-out mechanism 78 via the britension device 52. The needle thread 14 that reaches the end is in a relaxed state. In this state where the needle thread 14 is loosened, the thread take-up 48 is raised as described above to tighten the needle thread 14, and then the restraint by the thread path regulating plate 56 and the movable ring 64 is released. The necessary amount of needle thread 14 is supplied to thread take-up 48 and sewing needle 12 by the cloth feeding action and needle swinging action by feed dog 23 .

Note that cloth feeding is performed even before the upper thread 14 is released, but the amount of the upper thread 14 consumed by this cloth feeding is replenished by the amount of elastic stretch of the upper thread 14, and when the upper thread 14 is released from the restraint. The upper thread 14 is supplied while the amount of elongation is resolved.

In this way, the timing of binding and releasing the upper thread 14 is automatically controlled according to the thickness of the upper thread 14, and the required amount of upper thread 14 determined by the cloth feed amount and needle swing amount is reliably replenished one after another. Therefore, the thread tension is optimal depending on the thickness of the upper thread 14.

Regarding the yarn path regulating plate 56 and the movable ring 64 of the yarn passage control device 54, as shown in FIG.
A groove 64b may be formed, and the movable ring 64 may be formed as shown in FIG.
The moving direction of the movable ring 64 may be inclined with respect to the thread path regulating plate 56, or the circumferential surface of the movable ring 64 may be formed into a cylindrical surface as shown in FIG. Further, although not shown, a member fixed to the movable plate 58 may be used instead of the movable ring 64 that contacts the regulating portion 56a of the yarn path regulating plate 56. Furthermore, as shown in FIG. 11, the regulating portion 56a is configured with a grooved idler ring 56A, the needle thread 14 is bent along the half circumference of the idler ring 56A, and the engaging member 64A in place of the movable ring 64 is replaced by the idler ring 56A. It is also possible to make contact with a point contact point.

Next, another embodiment of the yarn passage control device will be described with reference to FIG. 12.

This thread passage control device 54A includes a linear actuator 100 that drives the movable wheel 64, a displacement sensor 101 that detects the displacement of the movable wheel, a rotation angle sensor 102 that detects the rotation angle of the sewing machine main shaft 28, and a timing sensor 103. , and a control unit 104.

The linear actuator 100 includes a movable coil section 105 connected to a movable ring 64, and a movable coil section 105 connected to a movable ring 64.
a metal magnetic path forming frame 106 that supports the magnetic path so as to be vertically movable;
A permanent magnet 107 that creates a uniform magnetic field toward the moving coil section 105 is provided, and the vertical position of the moving coil section 105 is determined according to the strength of the current supplied to the moving coil section 105.

The displacement sensor 101 is composed of a potentiometer including a contact 109 provided on the movable wheel support section 108 of the movable coil section 105 and an electric resistor 110 connected to a reference voltage line.

The rotation angle sensor 102 is, for example, a disk plate having a large number of slits at equally divided positions on the circumference, which is fixed to the sewing machine main shaft 28, and the slits are detected by a light emitting part and a light receiving part.

The timing sensor 103 is configured to detect when the needle bar lO reaches the uppermost position using a limit switch or a proximity switch.

The control unit 104 includes a CPU (central processing unit) 111 and a ROM (read only memory) 11.
2, a RAM (random access memory) 113, an input/output interface 114, and a drive circuit 115 that outputs a drive current to the moving coil section 105 based on a control signal output from the CPU 11 via the input/output interface 114. and an A/D converter 116 that A/D converts the detection signal from the displacement sensor 101 and outputs it to the input/output interface 114, and the detection signals from the rotation angle sensor 102 and timing sensor 103 are respectively CPUI via input/output interface 114
It is output to 11. Input/output interface 114
, ROMI 12 and RAM 113 are connected to CPUI 11 via address bus, data bus and control bus.
It is connected to the.

The ROM 112 controls the linear actuator 100 based on the timing signal S1 from the timing sensor 103, the rotation angle signal S2 from the rotation angle sensor 102, and the displacement signal from the displacement sensor 101, and controls the movable wheel 64 and the yarn path regulating plate. A control program for controlling the thread path gap between the thread guide and the regulating portion 56a of the thread guide member 56 is stored in advance.

This control is relatively simple, so to explain it qualitatively below, as shown in FIG.
A predetermined drive current is output to the movable coil section 105, the movable ring 64 and the regulating section 56a maintain a contact state, and the needle thread 14 is held and restrained between them.

At the time when the predetermined number of rotation angle signals S2 are input, the drive current to the moving coil section 105 is changed to the main shaft 2 as shown by the curve IP.
8, the movable coil portion 105 gradually descends and the yarn path gap expands as shown by the curve cp.

Here, the rotation speed of the main shaft 28 is calculated from the rotation angle signal s2, and the curve CP corresponding to each rotation speed is stored in the ROMI 12 as a memory map.
The drive current is determined moment by moment by feedback control based on the displacement signal from 1, and as a result, the drive current becomes like the curve IP.

Similar to the embodiment described above, in order to make the operating speed when expanding the yarn guide gap proportional to the rotational speed of the main shaft 28, the curve CP corresponding to the rotational speed of the main shaft 28 is set in the ROM as described above.
112 memory map.

Control when reducing the thread path gap (when pinching and restraining the upper thread 14) is the same as above, and the timing for raising the movable coil section 105 is determined by counting the rotation angle signal S2. , the feedback control is executed based on the displacement signal so that the song IcQ stored in the memory map of the ROM 112 is executed.
The drive current to is controlled as shown by curve IQ.

As in the case of the curve MC in FIG. 5 in the above embodiment,
The thin needle thread 14 is released at a point EF and is pinched and restrained at a point EC, whereas the thick needle thread 14 is released at a point EF2 and is pinched and restrained at a point EC2.

In this other embodiment, the movable wheel 64 is driven by the linear actuator 100, but it is also possible to configure the movable wheel 64 to be driven by a stepping motor or the like.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic perspective view of a sewing machine, FIG. 2 is a perspective view of the main parts of the internal mechanism built into the arm and head of the sewing machine, and FIG. 3 is a schematic perspective view of the sewing machine. 4 is a front view of the internal mechanism, FIG. 5 is a time chart showing the operation of each mechanism of the sewing machine, FIG. 6 is a sectional view taken along line vt-Vl in FIG. 3, and FIG. The figure is a sectional view taken along the line ■-■ in FIG. 4, FIGS. 8 to 11 are schematic diagrams corresponding to modified example 6' and FIG. 6, and FIG. 12 is a diagram of a yarn passage control device according to another embodiment. The configuration diagram and FIG. 13 are operation time charts of timing signals, rotation angle signals, coil drive currents, and yarn guide gaps. M... Sewing machine, 10... Needle bar, 12... Sewing needle,
14... Upper thread, 16... Thread spool, 22... Throat plate, 24
...Needle bar guide, 28..Sewing machine main shaft, 34..Subshaft, 36..Swing lever, 38..Take-up crank.
40...Crank pin, 42...Cam hole, 42a
・・Circular hole, 48・・Take-up lever, 48a・・Thread holding part,
54, 54A... Yarn passage control device, 56... Thread path regulation plate, 56a... Regulation part, 56A... Idle ring, 58
・・Movable plate, 60・・Link arm, 62・・Stepped screw, 64・・Movable ring, 64A・・Engagement member,
66... Spring, 68... Contact ring, 7°... Rotating cam, 72... Cam groove, 74... First arm, 76...
・Second arm, 100...linear actuator,
101... Displacement sensor, 102... Rotation angle sensor,
103...timing sensor, 104...control unit, 105...movable coil section. Patent applicant Brother Industries, Ltd.Forward Figure 3 Figure 4 Figure 6 Figure 3m Figure 7 Figure 1 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Qp t, u

Claims (3)

[Claims] (1) Permission and prohibition of passage of sewing thread in the thread supply path from the thread supply source to the eye of the sewing needle via the thread take-up body, and in the thread supply path between the thread supply source and the thread take-up body A sewing machine equipped with a pair of thread engaging bodies that are movable relative to each other in order to perform the above operations, and a thread passage control device that controls the approach and separation of the both thread engaging bodies, at least the approach and separation of the both thread engaging bodies. A sewing machine capable of controlling thread passage, characterized in that the thread passage control device is provided with a speed proportional means operatively connected to the sewing machine main shaft to make the speed of one operation proportional to the rotational speed of the sewing machine main shaft. (2) The speed proportional means is composed of a cam body which is operatively connected to the main shaft of the sewing machine and has an oval cam surface, and the thread passage control device moves the two thread engaging bodies toward and away from each other according to the cam surface of the cam body. A sewing machine capable of controlling thread passage according to claim 1, characterized in that the sewing machine controls the thread passage. (3) The speed proportional means includes a rotating body operably connected to the main shaft of the sewing machine, and a detector that detects rotation of the rotating body by a predetermined unit angle and generates rotation pulses, and the speed proportional means includes the thread passage control device. The thread according to claim 1, characterized in that the relative position of both thread engaging bodies is changed in synchronization with the rotation pulse during at least one of approaching and separating the thread engaging bodies. Sewing machine with controllable passage.