JP3528252B2 - Sewing machine presser foot device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cloth presser device for a sewing machine used when sewing cloth-like materials such as silk cloth or leather.

[0002]

2. Description of the Related Art As a technique of this kind, Jitsuko Sho 61-7
The technique disclosed in Japanese Patent No. 660 is known. This technique will be described with reference to FIGS. 5 and 6. 100 moves up and down in conjunction with a main shaft of a sewing machine (not shown), and a needle 101 is provided at the lower end.
A needle bar provided with 102, 102 is a locking body fixed to the middle part of the needle bar 100, and 103 is an annular ring fixed to the upper part of the needle bar 100. Reference numeral 104 is a guide bar fixedly supported by a machine frame 105 in parallel with the needle bar 100, and a stopper member 106 is fixed to the lower part thereof. 107 has a lower end formed with a pressing portion 107a which is inserted into the needle 101, and an upper end having a needle bar 10 above the locking body 102.
0 and the guide rod 104 are vertically movable support plates. Reference numeral 108 denotes a first elastic body that is locked at the upper end of the annular ring 103 having the upper end fixed to the needle bar 100 and the lower end is locked at the upper end of the presser plate 107 and is compressed in association with the lowering of the needle bar 10. When the cloth pressing plate 107 rises, it is slightly compressed from its natural length. Reference numeral 109 is a second elastic body interposed between the machine frame 110 at the upper end of the guide rod 104 and the upper end of the cloth pressing plate 107, and is compressed so as to press the cloth pressing plate 107 when the needle bar 100 and the cloth pressing plate 107 are raised. It is intervened so that it will be in the state of being.

Next, the operation of this technique will be described. When the sewing machine is started from the state where the needle bar 100 and the cloth pressing plate 107 are in the raised position, the needle bar 100 descends. Then, the annular ring 103 also descends, and the cloth pressing plate 107 descends via the first elastic body 108. At this time, the first elastic body 108 gradually contracts and the pressure for pressing the cloth pressing plate 107 against the locking body 102 becomes large, while the second elastic body 109, on the contrary, is pressed.
Is gradually extended and the pressure for pressing the cloth pressing plate 107 against the locking body 102 becomes small, and the cloth pressing plate 107 follows the locking body 102 and descends. The cloth pressing plate 107 comes into contact with the cloth 111 placed on a pedestal (not shown), so that the cloth pressing plate 107 is prevented from descending and the first elastic body 1
Jumping is prevented by 08, and only the needle 101 is further lowered to the state shown in the figure. After that, when the needle bar 100 rises and the locking body 102 abuts on the cloth pressing plate 107 to try to raise the cloth pressing plate 107, the first elastic body 108 gradually expands and presses the cloth pressing plate 107. However, this time, the second elastic body 109 gradually contracts and the force pressing the cloth pressing plate 107 against the locking body 102 gradually increases, and the cloth pressing plate 107 moves when the cloth pressing plate 107 moves up. Locking body 1
02, the jumping of the presser foot plate 107 is prevented.

As described above, in this technique, the cloth pressing plate 107 is moved up and down by the first elastic member 108 and the second elastic member 109 so as to follow the needle bar 100 and move up and down.
No. 07 jumping is prevented, and there is no variation in the elastic force of each elastic body acting on the needle bar 100.
Vibration due to uneven vertical movement of 0 is eliminated, and the needle bar 100 can be driven at high speed.

[0005]

However, in the technique described above, the work clamp plate 107 is moved by the vertical movement of the needle bar 100.
The locking portion 102 and the cloth pressing plate 107 and the stopper member 106 collide with each other, and a collision sound is generated at such a position. When the collision sound is driven at a high speed and in a high cycle, this collision noise causes a very high noise level and deteriorates the working environment.

In order to solve this problem, Japanese Patent Laid-Open No. 2-12
It is conceivable to use the technique disclosed in Japanese Patent No. 8787. In this method, the cloth pressing plate is interlocked with the vertical movement of the needle bar by a cam action. However, another drive mechanism for driving the cloth pressing plate is required, resulting in high cost.

A technical object of the present invention is to provide a cloth pressing device for a sewing machine which is low in cost and low in noise.

[0008]

In order to solve the above-mentioned technical problem, the technical means taken in the invention of claim 1 is a needle having a needle attached at its lower end which moves up and down in association with the rotation of the sewing machine main shaft. A rod, a cloth pressing plate disposed so as to be relatively movable in the axial direction of the needle bar, and having a cloth pressing portion at its lower end; a spring arranged between the needle bar and the cloth pressing plate; and a sewing machine. A positioning stopper that is provided on the frame to identify the lowermost position of the pressure plate, and begins to damp the movement of the pressure plate immediately before the pressure plate comes into contact with the positioning stopper. And a damping means for reducing the impact when the holding plate collides with the positioning stopper.

In order to further reduce the noise, the technical measure taken in the invention of claim 2 is that the positioning stopper has elasticity.

In order to reduce the cost, the technical means taken in the invention of claim 3 is such that the damping means is arranged between the presser plate and the positioning stopper, and the presser plate contacts the positioning stopper. It is a compression coil spring having one end that comes into contact with the cloth pressing plate immediately before.

[0011]

According to the first aspect of the present invention, when the needle bar moves downward in conjunction with the rotation of the main shaft of the sewing machine, the spring contracts and the biasing force generated at this time causes the cloth pressing plate to move downward. Immediately before the cloth pressing plate collides with the positioning stopper, the lowering speed of only the cloth pressing plate is lowered by the damping means, and the cloth pressing plate is brought into contact with the positioning stopper. After that, only the needle bar moves downward in conjunction with the spindle. On the other hand, when the needle bar moves up, it is moved up in conjunction with the rotation of the sewing machine main shaft.

According to the second aspect of the present invention, it is possible to absorb the impact force when the cloth pressing plate comes into contact with the positioning stopper by the elasticity of the positioning stopper.

According to the third aspect of the present invention, the downward movement speed is reduced by contacting one end of the compression coil spring immediately before the presser plate contacts the positioning stopper.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described with reference to the drawings.

1 to 4 are front views of a cloth pressing device for a sewing machine according to this embodiment. As shown in the figure, 10 is a head portion which is a machine frame equipped with the cloth pressing device of the present invention. The head portion 10 is also a machine frame and holds a needle bar 11 slidably up and down. The holding member 10a for holding is fixed, and the needle bar 11 is held by the sliding portions 10b, 10c of the holding member 10a so as to be vertically slidable. Further, the head unit 10 has a built-in well-known drive mechanism that is driven by a main shaft (not shown) to vertically move the needle bar 11.

The needle bar 11 is provided with an engaging portion 11a which is connected to the output member 12 of the drive mechanism, and the output member 1
The needle bar 11 is driven up and down by moving the needle bar 2 up and down. Head 1 with large diameter of needle bar 11
The return spring 13 whose one end is in contact with the supporting portion 10a of the head portion 10 is in contact with 1b, and the needle bar 1
1 is always biased upward. A locking portion 11c is formed at the center of the needle bar 11, and one end of the spring 14 is in contact with the locking portion 11c. A needle 15 is attached to the lower end of the needle bar 11. Also, the needle bar 11
The cloth pressing plate 16 is inserted through the needle bar 11 so as to be slidable in the axial direction.

The cloth pressing plate 16 has a cloth pressing portion 16a at the lower end. On the other hand, the upper end contacts the other end of the spring 14 and is urged downward in the normal state (FIG. 1).
In this embodiment, the spring 14 is composed of a compression coil spring, but the locking portion 11c of the needle bar 11 is arranged below the upper end of the presser plate 16 and a tension coil spring is arranged between them. You may. Also, the presser foot plate 1
A compression coil spring 17, which is a damping means for reducing the downward movement speed of the needle bar 11 when the needle bar 11 moves downward simultaneously with the downward movement, is provided on the sliding portion 10c of the holding member 10a. . Further, the positioning stopper 18 for specifying the lower end position of the cloth pressing plate 16 is provided with the sliding portion 10c of the holding member 10a.
Is mounted on.

In the figure, 19 is a thread hook and 20 is a cloth placed on a pedestal not shown.

Next, the operation of this embodiment will be described.

When the sewing machine is driven and the drive mechanism operates, the output member 12 of the drive mechanism first moves downward, and the needle bar 11 moves downward against the biasing force of the return spring 13. The downward movement of the needle bar 11 causes the spring 14 to be compressed, and the pressing force of the spring 14 causes the cloth pressing plate 16 to move downward.

When the needle bar 11 is moved down to the position shown in FIG. 2, the upper end of the cloth pressing plate 16 contacts the upper end of the compression coil spring 17, and the mechanical energy of the cloth pressing plate 16 and the spring 14 are increased. Presser plate 1 by biasing force
6 moves downward while compressing the compression coil spring 17. At this time, the downward movement speed of the cloth pressing plate 16 decreases in the process of compressing the compression coil spring 17, and the cloth pressing plate 16 contacts the positioning stopper 18 at a low speed.
At this time, if the positioning stopper 18 is made of an elastic body in advance, it is possible to further reduce the collision noise when the cloth pressing plate 16 contacts the positioning stopper 18.

The lower end position of the cloth pressing plate 16 is preset by the positioning stopper 18 to be about 0.5 mm from the upper surface of the pedestal.

After the cloth pressing plate 16 comes into contact with the positioning stopper 18, only the needle bar 11 is moved downward against the urging force of the spring 14 and the cloth 15 is stabbed with the needle 15.

On the other hand, when the needle bar 11 is moved up, it is moved up by the opposite action.

In the cloth pressing device of the present embodiment, the downward movement speed of the cloth pressing plate 16 is reduced by the compression coil spring 17 before the cloth pressing plate 16 contacts the positioning stopper 18, so that Positioning stopper 18
It is possible to reduce the collision sound with and to reduce the noise.

Further, since the cloth pressing plate 16 and the needle bar 11 are driven by one driving device, the cost is low.

Further, the damping means of the present embodiment employs a compression coil spring which can reduce the lower moving speed of the cloth pressing plate 16 at a low cost, but the invention is not limited to this, and a leaf spring or a bamboo shoot is used. Not only the spring, but also the air cushion,
A fluid-using elastic body such as a hydraulic cushion is included.

[0028]

According to the first aspect of the invention, since the lowering speed of the cloth pressing plate is reduced by the damping means immediately before the cloth pressing plate contacts the positioning stopper, the collision noise between the cloth pressing plate and the positioning stopper is reduced. Can be reduced and noise can be reduced. Further, since the cloth pressing plate and the needle bar are driven by one driving device, the cost is low.

According to the second aspect of the present invention, the impact force when the cloth pressing plate contacts the positioning stopper can be absorbed by the elasticity of the positioning stopper, so that the noise can be further reduced.

According to the third aspect of the present invention, the damping means is constituted by the compression coil spring, so that the lower moving speed of the cloth pressing plate can be reduced at low cost.

[Brief description of drawings]

FIG. 1 shows a front view of a cloth presser device for a sewing machine according to the present invention.

FIG. 2 shows a front view of a sewing machine presser device according to the present invention.

FIG. 3 is a front view of a cloth pressing device for a sewing machine according to the present invention.

FIG. 4 is a front view of a cloth pressing device for a sewing machine according to the present invention.

FIG. 5 shows a front view of a conventional presser foot device for a sewing machine.

FIG. 6 shows a front view of a conventional cloth pressing device for a sewing machine.

[Explanation of symbols]

10 ... Arm part (machine frame) 10a ... Holding member (machine frame) 11 ... Needle bar 11c ... Locking part 13 ... Return spring 14 ... Spring 15 ... Needle 16 ... Cloth holding plate 16a: cloth presser section 17 ... Compression coil spring (damping means) 18 ... Positioning stopper

Claims (3)

(57) [Claims] 1. A needle bar, which moves up and down in association with the rotation of a main shaft of a sewing machine and has a needle attached to a lower end thereof, is arranged so as to be relatively movable in an axial direction of the needle bar, and has a cloth pressing portion at its lower end. The presser foot plate, a spring disposed between the needle bar and the presser foot plate, a positioning stopper provided on the machine frame for identifying the lowermost end position of the presser foot plate, and the positioning stopper. Damping that begins to damp the movement of the cloth pressing plate immediately before the cloth pressing plate abuts and reduces the impact when the cloth pressing plate collides with the positioning stopper between the cloth pressing plate and the positioning stopper. And a means for pressing down the sewing machine. 2. The cloth pressing device for a sewing machine according to claim 1, wherein the positioning stopper has elasticity. 3. The compression means is arranged between the cloth pressing plate and the positioning stopper, and has one end for contacting the cloth pressing plate immediately before the cloth pressing plate contacts the positioning stopper. A cloth presser for a sewing machine according to claim 1 or 2, wherein the cloth presser is a coil spring.