JPH08332290A - Middle presser mechanism of sewing machine - Google Patents

Abstract

(57) [Summary] [Purpose] A middle presser foot for a sewing machine that can surely knot the upper thread and the lower thread at the start of sewing and that prevents the flap of the cloth at the end of sewing to reliably perform thread cutting. Provide a mechanism. [Structure] An intermediate presser bar 18 having an intermediate presser 19 attached to a lower end thereof by swinging the upper shaft 2 of a sewing machine to swing up and down.
A link mechanism for moving the needle 21 up and down in synchronization with the vertical movement of the needle 21 is provided, and an adjusting drive link 28 for adjusting the vertical position of the intermediate presser 19 by moving the position of the link mechanism by the adjusting drive motor 23 is provided. A control device 29 for driving and controlling the adjusting drive motor 23 is arranged so that the intermediate presser is slightly lowered to press the cloth at the start of sewing or at the end of sewing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a middle presser mechanism for a sewing machine, and more particularly to a middle presser for vertically moving the middle presser for pressing the cloth when the needle pierces the cloth in synchronization with the vertical movement of the needle. Regarding the presser mechanism.

[0002]

2. Description of the Related Art Generally, in a sewing machine, an upper shaft disposed inside a main body is rotated and a needle bar having a needle attached thereto is reciprocally moved up and down through a predetermined driving mechanism to make a predetermined movement. The cloth is sewn.

In this case, for example, Japanese Patent Publication 6
As disclosed in Japanese Laid-Open Patent Publication No. 2-43709, there is one that is provided on the outer peripheral side of the needle and is provided with an intermediate presser for pressing the cloth when the needle pierces the cloth. The intermediate presser mechanism, which is a link mechanism, is driven so as to move up and down in synchronization with the up and down movement of the needle bar on which the needle is mounted.

[0004]

However, in the above-mentioned conventional intermediate presser mechanism, since the intermediate presser is always operated at a constant height according to the cloth thickness at the time of sewing, the thread end is sewn at the start of sewing. If the cloth is not fixed and the cloth is not securely fixed, the upper thread and the lower thread are less likely to be knotted, a seam may not be formed, and there is a problem that defective sewing occurs. Further, since the cloth follows with the vertical movement of the needle, the cloth flaps, and there is a problem that a thread trimming defect is likely to occur at the time of thread trimming at the end of sewing.

The present invention has been made in view of the above points, and the upper thread and the lower thread can be surely knotted at the start of sewing, and the flap of the cloth can be prevented at the end of sewing to reliably cut the thread. It is an object of the present invention to provide a middle presser mechanism for a sewing machine capable of performing the above.

[0006]

In order to achieve the above-mentioned object, an intermediate presser mechanism of a sewing machine according to the present invention has an intermediate presser bar having an intermediate presser attached to a lower end portion thereof, and a needle of the sewing machine is moved up and down through a link mechanism. In the intermediate presser mechanism of the sewing machine that moves up and down in synchronization with the movement, an adjustment drive mechanism that adjusts the vertical position of the intermediate presser by moving the position of the link mechanism by the adjustment drive motor is provided, and at the start of sewing or the end of sewing. It is characterized in that a control device for driving and controlling the adjustment drive motor is arranged so as to slightly lower the intermediate presser and press the cloth.

[0007]

According to the intermediate presser mechanism of the sewing machine of the present invention, the height of the intermediate presser is set in advance only during the sewing of several stitches by controlling the drive of the adjusting drive motor by the control device at the start of sewing. Since it is adjusted so that it is slightly lower than the height position, the cloth can be securely fixed at the start of sewing, and moreover, the upper thread sewn at the first stitch is Since it is pressed and fixed when sewing at the second stitch, the upper thread and the lower thread can be surely knotted at the second stitch. And after sewing a few stitches,
The controller drives the adjustment drive motor to return the intermediate presser to the height corresponding to the cloth thickness to continue sewing, and when the cloth moves to the sewing end position, the controller drives and controls the adjustment drive motor to Adjust the height of the presser foot so that it is slightly lower, so that the cloth can be securely fixed and the cloth can be prevented from fluttering due to the vertical movement of the needle. It is the one that can do the work.

[0008]

Embodiments of the present invention will be described below with reference to FIGS.

1 and 2 show an embodiment of an intermediate presser mechanism of a sewing machine according to the present invention. Inside a sewing machine arm 1, a long upper shaft 2 is rotated by a drive device (not shown). An eccentric cam 3 having an outer peripheral surface eccentric with respect to the upper shaft 2 is attached to the outer periphery of the upper shaft 2 in the middle of the drive shaft. Further, a connection link 4 driven by rotation of the eccentric cam 3 is attached to the outer periphery of the eccentric cam 3, and a guide pin 5 projecting in the lateral direction is attached to the tip of the connection link 4. Has been.

An intermediate presser drive shaft 6 extending substantially parallel to the upper shaft 2 is rotatably disposed inside the sewing machine arm 1. One end of the intermediate presser drive shaft 6 is rotatable. A swing member 7 is attached to the. A guide arm 9 in which an arc-shaped guide hole 8 is formed is integrally fixed below the swing member 7, and the guide pin 8 of the connection link 4 is inserted into the guide hole 8 of the guide arm 9. Engaged.

At the other end of the intermediate presser drive shaft 6,
A first link 11 is connected via a swing arm 10, and an upper end portion of an L-shaped link 12 having an L shape is connected to a tip end portion of the first link 11. As shown in FIG. 2, the L-shaped link 12 has a central portion supported by a support shaft 14 that is axially supported by a stopper plate 13 so as to regulate the vertical position. 1
2 is swingable up and down with the support shaft 14 in the center as a fulcrum.

Further, at the tip of the L-shaped link 12,
The second link 15 is connected, and the second link 15 is connected.
The guide groove 16 formed inside the sewing machine arm 1.
An intermediate presser bar hanger 17 is vertically guided along the link. An intermediate presser bar 18 extending vertically inside the sewing machine arm 1 and having a lower end projecting from the lower side of the sewing machine arm 1 is attached to the intermediate presser bar hanger 17. The lower end of the intermediate presser bar 18 is attached. Intermediate presser foot 19 has a set screw 2
0 is attached. The intermediate presser 19 is formed with a hole 22 through which a needle 21 that is reciprocally moved up and down by a rotational drive of the upper shaft 2 through a drive mechanism (not shown) penetrates.

An adjusting drive motor 23 such as a pulse motor is arranged inside the sewing machine arm 1.
An output helical gear 25 is attached to the output shaft 24 of the adjustment drive motor 23. A drive bevel gear 27 attached to the adjustment drive shaft 26 is meshed with the output bevel gear 25, and the output bevel gear 25 and the drive are driven by the adjustment drive motor 23. The adjusting drive shaft 26 is rotationally driven via a helical gear 27. At one end of the adjusting drive shaft 26,
The adjustment drive link 28 is eccentrically connected, and the tip of the adjustment drive link 28 is connected to the support shaft 14 that supports the L-shaped link 12. Then, by rotating the adjustment drive shaft 26 to move the adjustment drive link 28, the support shaft 14 is moved back and forth with respect to the stopper plate 13, and thereby the center position of the L-shaped link 12 is moved. The position of the tip of the L-shaped link 12 can be adjusted up and down.

A control device 29 is connected to the adjusting drive motor 23, and the control device 29 controls the cloth 3
The height adjusting position of the intermediate presser 19 based on the predetermined sewing data of 0 is stored, and the adjusting drive motor 23 is driven based on the stored data to control the height of the bottom dead center of the intermediate presser 19. To do. Further, in the present embodiment, the control device 29 controls the height of the intermediate presser 19 to be lower than the preset height position by about 1 to 2 mm only during the sewing of a few stitches at the start of sewing. The adjustment drive motor 23 is drive-controlled, and at the end of sewing, the adjustment drive motor 23 is drive-controlled so that the height of the intermediate presser 19 is lower than the preset height position by 1 to 2 mm when the last needle is sewn. It is done like this.

Next, the operation of this embodiment will be described.

In the present embodiment, for example, as shown in FIG. 3, when sewing a cloth 30 whose cloth thickness changes in the middle, first, the height of the cloth 30 at the initial sewing position (position B) is set. Accordingly, the height position of the intermediate presser 19 is adjusted by the set screw 20, and then the cloth 30 is moved to the cloth thickness change position (C position) according to the sewing data, and the cloth thickness of this portion is changed. Adjust the height position of the intermediate presser 19. That is, by driving the adjustment drive motor 23 to rotate the adjustment drive shaft 26 via the output helical gear 25 and the drive helical gear 27, the adjustment drive link 28 is obtained.
Is moved and the support shaft 14 is moved back and forth with respect to the stopper plate 13, whereby the center position of the L-shaped link 12 is moved and the position of the tip end portion of the L-shaped link 12 is moved up and down. Therefore, the intermediate presser bar 1 is held via the intermediate presser bar hug 17
8 moves up and down, and the height position of the intermediate presser 19 can be adjusted. By the above work, the control device 29 is
The position at which the bottom dead center of the intermediate presser 19 is changed in the sewing operation of the cloth 30 is stored in advance.

Next, when sewing is started, the upper shaft 2
By rotationally driving, the connection link 4 is moved via the eccentric cam 3, the guide pin 5 is moved, and accordingly, the swing member 7 is swung via the guide hole 8, and the intermediate presser drive shaft is driven. 6 is rotationally driven. The rotation of the intermediate presser drive shaft 6 moves the first link 11 in the front-rear direction via the swing arm 10, whereby the L-shaped link 12 swings up and down about the support shaft 14. The intermediate presser bar holder 17 is reciprocally moved up and down along the guide groove 16 via the second link 15, and the intermediate presser bar 18 is driven vertically to reciprocate the intermediate presser 19 up and down. On the other hand, the needle 21 is also reciprocally moved up and down by the rotational drive of the upper shaft 2, and the operation of the intermediate presser 19 is performed in synchronization with the operation of the needle 21.

In this case, in the present embodiment, at the start of sewing (position A), the controller 29 drives and controls the adjustment drive motor 23 so that the intermediate presser 19 can be sewn only while sewing a few stitches. Height is 1 from the preset height position
Since it is adjusted so that the cloth 30 is lowered by about 2 mm, the cloth 30 can be reliably fixed at the start of sewing, as shown in FIG. 4, and the intermediate presser 1
According to 9, since the upper thread sewn at the first stitch is pressed and fixed when sewing at the second stitch, the upper thread and the lower thread can be surely knotted at the second stitch.

After sewing a few stitches, the controller 29 drives the adjusting drive motor 23 to drive the intermediate presser 1
9 is returned to the height corresponding to the cloth thickness, sewing is continued, and when the cloth 30 moves to the position (C position) where the cloth thickness changes, the controller 29 adjusts it based on the data stored in advance. The drive motor 23 is driven to raise the intermediate presser foot 19 to a height according to the cloth thickness, and sewing is continued.

Then, the cloth 30 is placed at the sewing end position (D position).
Is moved, the adjustment drive motor 23 is driven and controlled by the control device 29 to adjust the height position of the intermediate presser 19 to 1 to 2 m.
Adjust so that it is about m lower. This allows the cloth 3
0 can be reliably fixed, and the cloth 30 can be prevented from fluttering due to the vertical movement of the needle 21, so that the thread cutting operation can be reliably performed.

Therefore, in this embodiment, the adjusting drive motor 23 is controlled by the control device 29 at the start of sewing to adjust the intermediate presser 19 so as to slightly lower it. Since the cloth 30 can be fixed to the upper thread, and the upper presser thread sewn at the first stitch is pressed and fixed by the intermediate presser 19 when the second stitch is sewn, the upper thread is surely fixed at the second needle. And the lower thread can be knotted. Also, when the sewing is completed, the intermediate presser 1
Since the adjustment is made so that 9 is slightly lowered, the cloth 30 can be securely fixed, and the needle 21
Since the cloth 30 can be prevented from fluttering due to the vertical movement of the thread, the thread cutting operation can be reliably performed.

In the embodiment, the control device 29 is made to store in advance the height adjusting position of the intermediate presser 19 based on the predetermined sewing data of the cloth 30, and the adjusting drive motor 23 is operated based on this stored data. Although the height of the bottom dead center of the intermediate presser 19 is controlled by driving, for example, the controller 29 does not store the height adjusting position of the intermediate presser 19 and sends a sewing start signal at the start of sewing of the sewing machine. When inputting, the height of the intermediate presser 19 is adjusted to be lower than the preset height position by about 1 to 2 mm.
3 drive control and adjust the height of the intermediate presser 19 to be 1 to 2 mm lower than the preset height position when sewing the last stitch when a signal for thread trimming is input at the end of sewing. You may make it drive-control the drive motor 23.

Further, the present invention is not limited to the above-mentioned embodiment, and for example, the above-mentioned conventional Japanese Patent Publication No. 62-43.
It is possible to apply various modifications as necessary, such as a structure in which the intermediate presser is moved up and down via a link mechanism according to the vertical movement of the needle bar as shown in Japanese Patent Publication No. 709. is there.

[0024]

As described above, in the intermediate presser mechanism of the sewing machine according to the present invention, the intermediate presser is slightly lowered at the start of sewing, so that the cloth can be securely fixed at the start of sewing, and , With the intermediate presser, the upper thread sewn at the first stitch is pressed and fixed when sewing at the second stitch.
The needle thread can surely knot the upper thread and the lower thread.
In addition, the intermediate presser is also lowered slightly at the end of sewing as well, so that the cloth can be securely fixed and the cloth can be prevented from fluttering due to the vertical movement of the needle, so that the thread can be reliably There is an effect that cutting work can be performed.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an intermediate presser mechanism of a sewing machine according to the present invention.

FIG. 2 is a front view in which a part of the adjustment link portion of FIG. 1 is shown in section.

FIG. 3 is an explanatory view showing an intermediate presser height at the time of sewing by the intermediate presser mechanism of the present invention.

FIG. 4 (a) is an explanatory view showing a sewing state of the first stitch at the start of sewing by the intermediate presser mechanism of the present invention, and FIG. 4 (b) is a second stitch at the start of sewing by the intermediate presser mechanism of the present invention. Explanatory drawing showing the sewing state of

[Explanation of symbols]

 1 sewing machine arm 2 upper shaft 6 intermediate presser drive shaft 12 L-type link 13 stopper plate 14 support shaft 18 intermediate presser bar 19 intermediate presser 21 needle 23 adjustment drive motor 28 adjustment drive link 29 control device 30 cloth

Claims (1)

[Claims] 1. An intermediate presser mechanism for a sewing machine, wherein an intermediate presser bar having an intermediate presser attached to its lower end is moved up and down in synchronism with the vertical movement of a needle of the sewing machine via a link mechanism. An adjustment drive mechanism for adjusting the vertical position of the intermediate presser by moving the position of the mechanism is provided, and the adjustment drive motor is driven so as to slightly lower the intermediate presser and press the cloth at the start or the end of sewing. An intermediate presser mechanism for a sewing machine, which is provided with a control device for controlling.