JPH10165680A - sewing machine - Google Patents

Abstract

(57) [Summary] In a sewing machine provided with a thread tension device and a presser lifting device, both are driven by the same actuator, and the yarn is easily fed out during operation of the presser lifting device. SOLUTION: A stepping motor 44 which is an actuator of a thread tension device 22 is used to control a presser lifting interlock device 24.
Is rotated, and the cam 54
, The auxiliary roller 48 is separated from the main roller 46 to facilitate the feeding of the yarn 20. Further, the slide link 58 is driven by the contact 56 driven by the cam 54, and the cloth presser 14 is raised via the presser lifting link 32 and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine and, more particularly, to a sewing machine provided with a presser lifting device for lifting a cloth presser and a thread tensioner for electrically controlling the tension of a thread supplied to a needle or a looper. Regarding improvement.

[0002]

2. Description of the Related Art When sewing a cloth or the like in a sewing machine,
The vicinity of the needle is pressed by a cloth presser to stabilize the cloth, and at the time of non-sewing, the cloth presser is raised by a presser lifting device to release the cloth.

In general, an automatic presser lifting device for automatically raising a presser foot is configured to rotate a presser lifting drive motor by a presser switch, and to raise a presser bar supporting the presser foot by the rotation. Is configured.

[0004] On the other hand, when the presser foot is raised by the presser foot lifting device, it is necessary to allow the yarn to be smoothly fed out of the thread tensioner for threading and the like.

[0005]

As described above, when an automatic presser lifting device is used, it is necessary to provide an actuator such as a motor dedicated to the presser lifting device, and a large space for accommodating the dedicated actuator is required. Therefore, there is a problem that the shape of the sewing machine becomes large and the manufacturing cost increases.

Also, as described above, when the presser foot is raised,
The thread must be able to be smoothly unwound from the thread tensioner, but conventionally, the thread tensioner must be manually operated in conjunction with a lifting device to facilitate manual reeling out of the thread. However, there is a problem that it is complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and does not require a special actuator for the presser foot lifting device, and automatically raises the thread when the work clamp is raised. An object of the present invention is to provide a sewing machine that facilitates manual feeding of a thread from a tensioner.

[0008]

According to the present invention, there is provided a presser lifting device for pressing up a presser foot, and a thread tensioner for electrically controlling the tension of a yarn supplied to a needle or a looper. In the sewing machine provided, only at the time of presser lifting, the actuator of the thread tension device and the presser lifting device are interlocked, and the presser lifting device is driven by the actuator, and the restriction on manual thread feeding in the thread tension device is released. Alternatively, the above object is achieved by providing a presser-lift interlocking device that reduces.

According to a second aspect of the present invention, in the first aspect of the present invention, the actuator is disengaged from the presser lifting interlocking device when the actuator drives the thread tension device, and the actuator is disengaged from the thread tension device. And a one-way clutch for transmitting a driving force when operating in a direction opposite to the driving direction.

According to a third aspect of the present invention, in the first or second aspect, the thread tension device is provided with a thread tension side one-way clutch that transmits a driving force of the actuator only when driven by the actuator. It is a thing.

According to a fourth aspect of the present invention, in the first, second, or third aspect, the actuator is a motor, and
A main roller rotated in the yarn feeding direction by the motor, and the yarn tension device is detachable from and connected to the main roller;
An auxiliary roller for holding the yarn together with the main roller at the time of contact is provided, and the motor is controlled by a control device. A cam that is rotated in the same direction only when rotated in a direction opposite to the direction, and a presser lifting drive mechanism that is driven by the rotation of the cam to raise the cloth presser and separate the auxiliary roller from the main roller. The control device drives the motor in the direction opposite to the line feeding direction when the presser is lifted.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the actuator is used as a motor, and the thread tension device presses the thread by the pressure of a spring and adjusts the spring pressure to feed the thread. A thread tension plate for controlling tension;
The motor is configured to include a spring pressure changing unit that is driven to rotate by a motor and changes the spring pressure according to the rotation angle, and a control device that controls the rotation angle of the motor. A one-way clutch that transmits rotation only when rotating in a direction opposite to the direction in which the spring pressure changing unit is driven, and when driven through the one-way clutch, causes the thread tension device to move in the spring pressure reducing direction. And the control device drives the motor in the direction opposite to the driving direction of the spring pressure changing means when the presser is lifted.

In the present invention, the presser lifting device is driven by the actuator of the thread tension device, and at the same time, the manual feeding of the thread from the thread tension device is facilitated.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIGS. 1 to 3, the sewing machine 10 according to the present invention includes a presser foot 14 supported by a lower end of a presser bar 12 which is inclined downward and protrudes from an arm portion 10A.
Presser lifting device 1 for driving up and down together with the presser bar 12
6, a thread tension device 22 for controlling the tension and feeding of the thread 20 supplied to the needle 18, and a driving force of a drive source of the thread tension device 22 is transmitted to the presser lifting device 16, and the cloth presser 1
4 and a press-up interlocking device 24 for facilitating the feeding of the yarn from the yarn tension device 22. Reference numeral 25 in FIGS. 1 to 3 denotes a needle plate.

The presser lifting device 16 includes the presser bar 12.
Holding bar 26 at its tip, a vertically-long press-up connecting bar 28 having a lower end connected to a side surface from the base end to the vicinity of the front end of the pressing bar-holding bar 26, And a presser link 32 that is pivotally supported in the vertical plane by a fulcrum shaft 30 at the base end, and that drives the presser connecting rod 28 up and down by the swing. It is comprised including.

Reference numeral 12A in FIG. 1 denotes a presser holder for supporting the cloth presser 14 at the lower end of the presser bar 12 so as to be able to swing and adjust the position of the presser bar in the axial direction. Reference numeral 26A denotes a presser bar holding the presser bar 12. A screw 34 for fixing to the presser bar 26 abuts against the lower surface of the presser bar holder 26, and a presser lever for manual operation, which is disposed so as to be able to press up, 34A is a presser lever 34 for the presser The screws for rotatably fixing are respectively shown.

Reference numeral 12B in FIG. 1 and FIG.
A presser adjusting screw 12C screwed to the upper end of 2 indicates a spring mounted on the presser bar 12 at a position between the presser adjusting screw 12B and the presser bar hanger 26. The spring 12C urges the presser bar 12 in the upper end projecting direction via the presser adjusting screw 12B, and the presser adjusting screw 12B adjusts the set pressure of the spring 12C.

Reference numeral 38 in FIGS. 1 and 3 indicates a cloth thickness detecting sensor. The cloth thickness detection sensor 38 is rotatably supported by the frame 36 via a support plate 38A, and the tip of an arm 38B extending from the rotation axis is attached to the upper surface of the presser bar holder 26 via a pin 38C. By detecting the change in the height position of the presser bar clamp 26 due to the thickness of the cloth when the cloth presser 14 presses the cloth to be sewn by the cloth presser 14 by being pressed by the cloth 38D, the rotation angle of the arm 38B is detected. It is.

Reference numeral 40 in FIGS. 1 and 2 denotes a press-up sensor which is turned on by the upper end of the press-up link 28 when the press-up link 32 and the press-up connecting rod 28 are raised.

Next, the thread tension device 22 and the presser lifting interlocking device 24 will be described in detail with reference to FIGS.

The thread tension device 22 includes a stepping motor 4 supported on the frame 36 via a mounting plate 42.
4, a main roller 46 coaxially attached to an output shaft 44A of the stepping motor 44 via a one-way clutch 46A, and the main roller 46 so as to sandwich the thread 20 between the main roller 46 and the main roller 46. Auxiliary roller 48 which is arranged so as to be able to press against and freely rotates about a rotation axis 48A parallel to the main roller 46.
And a control device 50 configured to drive the stepping motor 44 to control the feed amount of the yarn 20 held between the main roller 46 and the auxiliary roller 48 for each stitch. Have been.

Reference numeral 48B in FIG. 3 denotes a mounting arm for supporting the auxiliary roller 48 via a rotating shaft 48A at the tip.
Is a fulcrum shaft for swingably supporting the mounting arm 48B in a plane perpendicular to the rotation axis 48A, 48D is a spring for biasing the mounting arm 48B in a direction in which the auxiliary roller 48 is pressed against the main roller 46, and 52 is Each shows a base tension device for applying a weak tension to the yarn 20.

The presser-lift interlocking device 24 includes a cam 54 coaxially mounted on the output shaft 44A of the stepping motor 44 via the one-way clutch 54A and the main roller 46, and a fulcrum shaft 56A on the mounting plate 42. Thus, the contact 56, which is arranged to be swingable in a plane parallel to the mounting plate 42 and perpendicular to the output shaft 44 </ b> A,
When the arm 6 is pivoted counterclockwise in FIG. 3, the mounting arm 48B supporting the auxiliary roller 48 is pushed in a direction in which the auxiliary roller 48 is separated from the main roller 46, and a slide link 58 (described later) is moved. In FIG. 3, the button is pushed to the left.

The slide link 58 is a plate-shaped member that is high in the direction perpendicular to the plane of FIG. 3 and is long in the left-right direction. In the longitudinal direction (left-right direction)
Is reciprocally supported.

The contact 56 has a substantially U-shape.
At the center position of the middle side of the U-shape, it is supported by the fulcrum shaft 56A, and at one end 57A (lower left end in FIG. 3) of the U-shape, it contacts the cam 54 and the middle side of the U-shape In FIG. 3, the slide link 58 and the mounting plate 60 pass between a pair of protrusions 58A and 58B (see FIG. 4) provided at predetermined positions of the slide link 58 above the fulcrum shaft 56A. Extending between
Here, it is bent in a direction parallel to the slide link 58 and abuts on the mounting arm 48B at the other end 57B opposite to the tip 57A.

Therefore, when the tip 57A of the contact 56 is pushed rightward in FIG. 3 by the cam 54, the contact 56 swings counterclockwise about the fulcrum shaft 56A, whereby The slide link 58 is pushed to the left in FIG.
3B, the mounting arm 48B is swung clockwise in FIG. 3 around the fulcrum shaft 48C against the tensile force of the spring 48D, and the auxiliary roller 48 at the tip of the mounting arm 48B is rotated by the main roller 46B. Is to be kept away from.

A projection 58C is formed on the slide link 58 at a position on the right side of the mounting arm 48B of the auxiliary roller 48 in FIG. 3 (see FIG. 4).
4 moves leftward in FIG. 4, the mounting arm 48B is pushed by this, and is swung.

There is a slight gap in the longitudinal direction of the slide link 58 between the contact 56 of the slide link 58 and the protrusion 58B on the left side thereof.
3 is slightly swung counterclockwise in FIG. 3, so that even when the auxiliary roller 48 is slightly separated from the main roller 46, the contact 56 does not push the projection 58B, and the slide link 58 is It is not driven by the contact 56 via the projection 58B.

The cam 54 is, as shown in FIG.
Minimum diameter circular arc portion 5 that does not press tip 57A of contact 56
5A, a maximum lift portion 55B protruding 180 ° from the center of the minimum diameter arc portion 55A to the opposite side, and intermediate lift portions 55C, 55D continuous with both sides of the minimum diameter arc portion 55A and having a larger diameter. And a cam surface comprising:

When the amount of lift of the intermediate lift portions 55C and 55D is such that the tip 57A of the contact 56 is pushed rightward in FIGS. 3 to 5, the contact 56 moves about the fulcrum shaft 56A. In a counterclockwise direction, the mounting arm 48B of the auxiliary roller 48 can be slightly pushed without contacting the projection 58B.

The lift amount of the maximum lift 55B is determined by the contact 56 pressing the mounting arm 48B and the protrusion 58B.
B, the slide link 58 is driven, whereby the presser bar 12 and the cloth presser 14 can be raised by a certain amount via the presser link 32 and the presser connecting rod 28.

Reference numeral 62 in FIGS. 3 and 4 denotes an origin sensor for detecting the origin position of the cam 54. Specifically, the contact 5
6 is pushed by the maximum lift portion 55B of the cam 54, when the U-shaped middle side of the contact 56 swings counterclockwise in FIGS. The rotation angle position of the stepping motor 44 is confirmed from the timing of the signal.

Further, reference numeral 64 in FIG. 3 denotes a friction plate. The friction plate 64 provides an appropriate frictional resistance to the main roller 46 and secures a holding force of the yarn 20 by the main roller 46. Things.

In FIG. 6, reference numeral 66 denotes a power switch, 68 denotes a sewing machine motor, and 100 denotes a presser U / D switch for instructing raising and lowering of the presser.

The stepping motor 44 in the yarn tensioning device 22 uses a main roller 46 and an auxiliary roller 48 to move the yarn 20 one stitch at a time. Control device 5
The thread amount calculated at 0 is fed out.
For example, JP-A-57-59592 and JP-B-57-2
Since it is publicly known in Japanese Patent Application Laid-Open No. 0835 and the like, detailed description will be omitted.

Next, the thread tension device 2 in the sewing machine 10 will be described.
2, the operation of the presser lifting interlocking device 24 and the presser lifting device 16 will be described.

First, when the power switch 66 is turned on, the control device 50 is activated and the stepping motor 44 is turned on.
Are driven clockwise in FIGS. 3 and 5. At this time, the main roller 46 is driven by the one-way clutch 46A.
Since it can rotate only in the counterclockwise direction, it is not driven by the stepping motor 44.

On the other hand, the cam 54 is
4A, the intermediate lift portion 55C is rotated clockwise by the stepping motor 44, and the intermediate lift portion 55C is moved to the tip 57A of the contact 56.
Push up.

As a result, the contact 56 is supported by the fulcrum shaft 56A.
At the center, the origin sensor 62 is turned on. The control device 50 stores the excitation phase in the stepping motor 44 at this time as the position of the most intermediate lift portion 55C according to the ON signal from the origin sensor 62.

As described above, the contact 56 is supported by the fulcrum shaft 56A.
Swings counterclockwise around the other end.
B pushes the mounting arm 48B supporting the auxiliary roller 48, so that the mounting arm 48B is swung in the direction in which the auxiliary roller 48 is separated from the main roller 46, and the main roller 46 and the auxiliary roller 4
There is a gap at a level that allows the thread 20 to pass therethrough.

In this state, since the contact 56 does not contact the projection 58B, the slide link 58 is
It does not move leftward in FIG.

When the stepping motor 44 further rotates clockwise, the maximum lift 55B of the cam 54 is
The contact 56 is further swung counterclockwise about the fulcrum shaft 56A by further pushing the tip 57A of the contact 6. At this time, the stepping motor 44 is stopped.

When the contact 56 swings, it comes into contact with the projection 58B and pushes the slide link 58 leftward in FIGS.

The lifting link 32 is driven by the leftward movement of the slide link 58, and the lifting link rod 28 engaged with the tip of the lifting link 32 is lifted.
The presser foot 14 is raised to a predetermined position via the presser bar holder 26 and the presser bar 12.

At this time, the lifting sensor 40 is turned ON by the lifting of the lifting rod 28. And presser foot U /
When the D switch 100 is turned on, the control device 50 further rotates the stepping motor 44 clockwise based on the ON signal, and the intermediate lift portion 55D on the left side in FIG.
After passing through the tip 57A of the contact 56, the minimum diameter arc portion 55
Stopped at position A.

At this time, the contact 56 in contact with the cam 54 is pushed back to the original position by the spring 48D via the mounting arm 48B, and at the same time, the slide link 58 is moved to the contact 5
It is pushed back to its original position by 6. As a result, the presser bar 12 and the presser foot 14 are lowered in the opposite direction until the presser foot 14 contacts the needle plate.

As described above, the rotation of the cam 54 in the clockwise direction causes the auxiliary roller 48 to be separated from and brought into contact with the main roller 46, and the cloth presser 14 is moved up and down. 46A, the main roller 4 rotates only in the counterclockwise direction.
6 is kept inactive.

During the period from immediately before the presser foot 14 is raised to the completion of the raising and lowering, the auxiliary roller 48 is
The thread 20 is separated from the thread 20 when, for example, threading is performed.
Can be paid out freely.

When the presser foot lifting switch 40 is turned on when the presser foot 14 is in the down state in which the presser foot 14 contacts the needle plate 25,
As in the case of turning on the power, the cam 54 rotates clockwise to separate the auxiliary roller 48 and to raise the cloth presser 14.
4 is stopped.

Here, the stepping motor 44
When the main roller 46 is driven to feed out the yarn 20, the stepping motor 44 is rotated counterclockwise in FIGS. The cam 54 is a one-way clutch 54A
, The cam 54 is not driven during the yarn feeding operation, and therefore, the auxiliary roller 48 is separated from the main roller 46, or the cloth presser 14 is raised. Absent.

The presser foot 14 can be raised through the presser bar holding member 26 by rotating the presser foot lifting lever 34 clockwise in FIG. 1 by manual operation. .

At this time, the presser foot connecting rod 28 also moves up,
Since the presser lifting sensor 40 is turned on, the clockwise driving of the cam 54 causes the mounting arm 48B of the auxiliary roller 48 to swing through the contact 56 as described above, and
Can be manually fed out.

The thread tension device 22 has a configuration in which the thread 20 is fed by the main roller 46 and the auxiliary roller 48. However, the present invention is not limited to this. There may be.

For example, the present invention is also applied to a thread tension device 70 using a thread tension plate shown in FIGS.

In the thread tension device 70, the thread 20 is sandwiched between a pair of thread tension plates 72A and 72B, and one thread tension plate 72B is pressed by a spring 74 toward the thread tension plate 72A. Is changed by spring pressure changing means 76, whereby the feeding and tension of the yarn 20 are controlled.

The spring pressure changing means 76 is operated by controlling the rotation angle of the stepping motor 44 by the same stepping motor 44 as described above.

The presser-lift interlocking device 78 for driving the presser-lifting device 16 is driven by the stepping motor 44 in the same manner as described above, but the other end 57 B of the contact 56 is connected to the spring 74. The difference is that the operation is performed to release or change the spring pressure applied to the thread tension disc. The other configuration is the same as that of the presser-lift interlocking device 24. Therefore, the description will be omitted by assigning the same reference numerals to the same portions.

The spring pressure changing means 76 in the thread tension device 70 is connected to the output shaft 44A of the stepping motor 44 by
A drive bevel gear 80 attached so as to be rotatable only in the counterclockwise direction in FIG. 7 through a one-way clutch 80A and a center of the pair of thread tension discs 72A and 72B, and an extension axis thereof is the stepping gear. Motor 4
4 and a center shaft 82 arranged to intersect at right angles with the extension axis of the output shaft 44A. The center shaft 82 is rotatably mounted on the center shaft 82, meshes with the drive bevel gear 80, and the thread tension discs 72A, 72B. Bevel gear 84 having a cam surface 84A on its side, the central shaft 82, the driven bevel gear 8
4 and the thread tension discs 72A and 72B, the driven bevel gear 8 is disposed so as to be axially movable along the central axis 82.
A driven plate 86 provided with a follower 86A following the cam surface 84A on the side surface on the fourth side, and the driven plate 86 and the thread tension plate 72
B and the spring 74 that presses the follower 86A of the driven plate 86 against the cam surface 84A and presses the thread tension disc 72B.

The driven plate 86 has a follower 86A having a spring 7
4 and follow the cam surface 84A, reciprocate along the central axis 82 in accordance with the change in the lift amount of the cam surface 84A in accordance with the rotation of the driven bevel gear 84, and thereby the spring applied to the thread tension plate 72B. The spring pressure at 74 is changed.

The presser lifting interlocking device 78 is inserted between the thread tension tray 72B and the spring 74, and when it is swung counterclockwise in FIG. 7 about the support shaft 88A, the spring 74 is contracted. And a spring pressure release lever 88 for reducing or releasing the spring pressure applied to the thread tension tray 72B.

The spring pressure release lever 88 is connected to the spring 7
The other end 57B of the contact 56 at the end opposite to 4
Thereby, it can be pressed counterclockwise.

Reference numeral 90 in FIG. 7 is an origin sensor for detecting the origin of the driven bevel gear 84, which detects the rotational angle position of the driven bevel gear 84 that rotates when the power is turned on or the like.
8 and 9, reference numeral 87 denotes the thread tension plates 72A and 72.
B, a guide shaft that penetrates the driven plate 86 in parallel with the central axis 82 and prevents rotation while allowing these to reciprocate in the central axis 82 direction.

In the thread tensioner 70, the pressing force of the spring 74 is changed by adjusting the angular position of the driven bevel gear 84 via the driving bevel gear 80 by the stepping motor 44 during normal sewing operation. , Thread tension plate 7
The tension applied to the yarn 20 is adjusted by 2A and 72B. At this time, since the driving bevel gear 80 is rotated counterclockwise in FIG. 7, the cam 54 is not driven to rotate.

On the other hand, at the time of the lifting operation, the stepping motor 44 is rotated clockwise in FIG. 7 as described above, whereby the cam 54 is also driven clockwise. At this time, the drive bevel gear 80 is connected to the one-way clutch 8
Due to 0A, it is not driven clockwise.

When the cam 54 is driven clockwise and the intermediate lift 55C slightly pushes the tip 57A of the contact 56, the contact 56 moves about the fulcrum shaft 56A as shown in FIG.
, The other end 57B swings the spring pressure release lever 88 counterclockwise, and the spring 74 is contracted by the spring pressure release lever 88, so that the thread tension plate 72B The pressing force of the applied spring 74 is released. Therefore, the yarn 20 can be fed out freely.

Further, when the cam 54 rotates clockwise,
The contact 56 is largely swung by the maximum lift portion 55B. However, since the contact 56 has the same operation as that of the presser-lift interlocking device 24 of FIGS.

In the above embodiment, the thread tension devices 22 and 70 are both driven by the stepping motor 44. This is because other actuators such as a servo motor, a DC motor, and a solenoid are used. May be used.

Each sensor is shown as a microswitch, but the present invention is not limited to this, and may be an optical sensor, a magnetic sensor, a potentiometer, or the like.

Further, the cam 54 is driven directly by the stepping motor 44. However, a cam provided at a position separated from the actuator via a gear or the like may be driven. In this case, the torque of the actuator can be reduced.

The press-lift interlocking device 24 interlocks the driving of the mounting arm 48B of the auxiliary roller 48 and the driving of the press-up connecting rod 28. In this case, the interlocking interlocking device 24 interlocks with the base tension device 52. This may be set to release and non-release of the tension applying force.

The main roller 46 in the thread tension device 22 is driven by a stepping motor 44 via a one-way clutch 46A. However, the present invention is not limited to this. May be directly driven by the actuator without passing through.

In this case, when the main roller 46 is rotated clockwise, the yarn 20 may be slightly pulled back. However, since the auxiliary roller 48 is separated from the main roller 46, the amount of pullback is ignored. It is possible.

In the above-described sewing machine, the presser foot 14 is raised by the driving force of the motor that feeds the needle thread. However, the present invention is not limited to this.
0, like the sewing machine 102 shown in FIG.
The presser lifting device 110 is driven via the presser lifting interlocking device 108 by the yarn feeding driving force of the upper looper thread actuator 106 that feeds the A and / or the lower looper thread actuator 106 that feeds the lower looper thread 106A. 112 may be raised.

The structure of the presser-lift interlocking device 108 is the same as that of the presser-lift interlocking device 24 or the presser-lift interlocking device 78 in the sewing machine 10, and therefore the description thereof is omitted.

In FIG. 10, reference numerals 114A and 114B denote stepping motors in the upper and lower looper thread actuators 104 and 106, 116A and 116B denote main rollers for feeding the looper thread in the upper and lower looper thread actuators 104 and 106, and 118A and 118B denote the main rollers. Auxiliary rollers, which are disposed so as to be able to be separated from and contacted with the main rollers 116A and 116B, hold the looper thread between the main rollers at the time of contact, and enable the looper thread to be fed by rotation of the main roller.
Reference numerals 20A and 120B denote springs for urging the auxiliary rollers 118A and 118B in a direction of pressing against the main rollers 116A and 116B, respectively.

Reference numeral 124 denotes a needle, and 126 denotes the needle 12.
4, a thread tension device similar to the thread tension device 22 for supplying the needle thread 126 to the needle 124, 130 is a needle plate, and 132A and 132B are
An upper looper and a lower looper are shown, respectively.

The upper looper 132A and the lower looper 132
For B, the upper looper thread 104A and the lower looper thread 106A are supplied from the upper and lower looper thread actuators 104 and 106 via a looper balance 134, respectively.

Further, reference numeral 136 in FIG.
The main rollers 138 in FIG. 8 are auxiliary rollers which are provided so as to be able to freely contact and separate from the main roller 136, and which cooperate with the main roller 136 to feed out the needle thread 126 at the time of contact.

[0080]

According to the present invention, the thread tension device and the presser lifting device can be driven by the same drive source, and the thread tension device is released while the presser lifting device is being driven. This has an excellent effect that the yarn can be easily fed out.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing a sewing machine according to the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a view taken along the line III-III in FIG. 2;

FIG. 4 is an enlarged sectional view showing a main part of FIG. 2;

FIG. 5 is an enlarged plan view showing a cam in the presser-lift interlocking device of the sewing machine.

FIG. 6 is a block diagram showing a control system of the sewing machine.

FIG. 7 is an enlarged plan view illustrating a main part of an example of another embodiment of the present invention.

FIG. 8 is a view taken along line VIII-VIII of FIG. 7;

FIG. 9 is a view taken along line IX-IX of FIG. 7;

FIG. 10 is a front view showing a main part of a sewing machine according to still another embodiment of the present invention.

[Explanation of symbols]

 10, 102 ... sewing machine 12 ... presser bar 14, 112 ... cloth presser 16, 110 ... presser lifting device 18, 124 ... needle 20 ... thread 22 ... thread tension device 24, 108 ... presser lifting interlocking device 40 ... presser lifting sensor 44 ... Stepping motors 46, 116A, 116B: Main rollers 46A, 54A: One-way clutches 48, 118A, 118B: Auxiliary rollers 48B: Mounting arms 50: Control device 54: Cam 56: Contacts 58: Slide links 58A, 58B: Projections 60 ... Mounting plate 70 ... Thread tension device 72A, 72B ... Thread tension plate 74 ... Spring 76 ... Spring pressure changing means 78 ... Holding interlocking device 80 ... Drive bevel gear 84 ... Driven bevel gear 88 ... Spring pressure release lever 100 ... Presser U / D switch 104: Upper looper thread actuator 106: Lower looper thread actuator 104A: Upper Looper thread 106A: Lower looper thread

Claims (5)

[Claims] A presser lifting device for lifting a cloth presser,
And a sewing machine provided with a thread tension device that electrically controls the tension of the thread. A sewing machine characterized in that: 2. The apparatus according to claim 1, wherein the presser-lift interlocking device is disengaged with the actuator when the actuator drives the thread tension device, and in a direction opposite to when the actuator drives the thread tension device. A one-way clutch for transmitting a driving force when the sewing machine operates. 3. The sewing machine according to claim 1, wherein the thread tension device is provided with a thread tension side one-way clutch for transmitting a driving force of the actuator only when driven by the actuator. . 4. An actuator according to claim 1, 2 or 3, wherein said actuator is a motor, said thread tension device is a main roller rotated in the yarn feeding direction by said motor, and said main roller is detachable from said main roller. , An auxiliary roller for pinching the yarn together with the main roller at the time of contact, and the motor is controlled by a control device, and the presser lifting interlocking device is
A cam that is rotated by the motor in the same direction only when the motor rotates in the direction opposite to the line feeding direction, and a cam that is driven by the rotation of the cam to raise the cloth presser and move the auxiliary roller from the main roller. A presser lifting drive mechanism for separating the motor, wherein the control device drives the motor in a direction opposite to a thread payout direction at the time of presser lifting. 5. The yarn actuator according to claim 1, 2 or 3, wherein the actuator is a motor, and the yarn tension device presses the yarn with a spring pressure, and controls the feeding and tension of the yarn by adjusting the spring pressure. And a control device for controlling the rotation angle of the motor, the spring pressure changing means being driven to rotate by the motor and changing the spring pressure according to the rotation angle thereof, The apparatus includes: a one-way clutch that transmits rotation only when the motor rotates in a direction opposite to a direction in which the spring pressure changing unit is driven; and a device that drives the thread tension device when driven through the one-way clutch. A spring pressure release device that drives in a direction to reduce the spring pressure of the thread tension disc. Sewing machine characterized in that it is adapted to drive.