JPH07299268A - Device for feeding cloth for sewing machine - Google Patents

Abstract

PURPOSE:To prevent the generation of a cripple and packering at the time of feeding the cloth in the sewing machine. CONSTITUTION:This device consists of a feed dog 2 having three lines of feeding part and a presser foot 1 arranged above the feed part at the center, having the same width with that of the feed part and provided with a freely rotatable roller 1a at the back of a needle location 1c of a presser foot 1b. When the roller 1a is protruded lower than the lower surface of the presser foot 1b, the upper surfaces of respective feed parts are made at the same height. When the roller 1a is not protruded below the lower surface of the presser foot 1b, a groove is formed at the lower surface of the presser foot 1b. The upper surface of the center feed part is made higher than the upper surface of the feed part on both sides.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cloth feeding device using a presser foot and a feed dog in a sewing machine.

[0002]

2. Description of the Related Art Conventionally, as a cloth feeding device for a sewing machine, FIG.
The one shown in 1 is known. The cloth feeding device includes a presser foot 1 and a feed dog 2. When the presser foot 1 presses the cloth 4 from above, the feed dog 2 makes an elliptical motion, and its tooth portion protrudes above the needle plate 3. The cloth 4 is fed in the direction of arrow A.

[0003]

In the cloth feed device for the sewing machine described above, only the lower cloth 4b is in direct contact with the feed dog 2, and the upper cloth 4a is pressed by the presser 1 in the direction of arrow B. It is only indirectly affected by the receiving and feeding teeth 2. Therefore, the amount of cloth fed by the elliptic movement of the feed dog 2 is larger in the lower cloth 4b than in the upper cloth 4a. Therefore, in the state after sewing, as shown in FIG. 12, wrinkles are generated on the lower cloth 4b, and as a result, the cloths 4a, 4
The shift occurs at the sewing end of b. The difference L is said to be the amount of clams. The wrinkles on the lower cloth 4b also affect the upper cloth 4a, and wrinkles are generated. This wrinkle is called puckering. Crimping and puckering are problems that cannot be solved for a long time as a large sewing neck.

An object of the present invention is to prevent the occurrence of grinning and puckering during cloth feeding in a sewing machine.

[0005]

In order to achieve the above object, a cloth feeding device for a sewing machine according to the present invention comprises a feed bar and a roller which is rotated by its elliptical motion and which is provided behind a needle drop portion of a presser foot. The feed wire and the roller each have a surface for generating a frictional force between the cloth and the roller, or teeth having the same pitch or an integral multiple pitch with each other are formed. The position of the roller can be adjusted in the vertical direction, and the roller can freely rotate in either direction. A plurality of rows of feed portions may be formed on the feed wire, and the roller may be above the central feed portion and have substantially the same width. In that case, when the roller is protruding below the lower surface of the presser foot, the upper surface of each feed unit should be at the same height, and when the roller is not protruding below the lower surface of the presser foot, a groove is formed on the lower surface of the presser foot, The upper surface of the feeding section is higher than the upper surfaces of the feeding sections on both sides.

[0006]

In the cloth feeding device of the sewing machine configured as described above, the cloth is fed by the frictional force between the lower surface of the presser foot and the upper surface of the feeding portion at the both side feeding portions of the feed metal, and at the central feeding portion,
The upper cloth and the lower cloth are completely sandwiched between the roller and the upper surface of the feeding section, and two sheets are simultaneously fed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a cloth feeding device for a sewing machine according to the present invention will be described with reference to FIGS.

This cloth feeding device comprises a roller 1a, and a presser foot 1 for pressing the cloth on the needle plate 3 from above,
It is composed of a feed dog 2 that feeds cloth when the tooth portion protrudes to the upper surface of the needle plate 3 during the elliptical movement.

Needle drop portion 1c formed on the presser foot 1b
A hole 1d is formed on the rear side so that the lower portion of the roller 1a can project downward from the lower surface of the pressing portion 1b.

In the rear bent portion of the presser foot 1b, not-shown vertical holes are formed on the left and right respectively. The roller base 1e is attached to the roller base 1e through the elongated hole so that the position of the roller base 1e can be adjusted in the vertical direction B by two bolts 1h. The roller 1a is rotatably attached to the roller base 1e behind the needle drop portion 1c via a shaft 1f.
Therefore, the position of the roller 1a can be adjusted in the vertical direction B,
Moreover, the elliptic movement of the feed dog 2 allows the feed dog 2 to freely rotate in either direction.

As shown in FIG. 2, the feed dog 2 is usually provided with
There are three rows of teeth 2a, 2b, 2c, the tops of which are coplanar and integrally formed. Therefore, the teeth 2a, 2b, 2c move on the same elliptical orbit at the same speed.

The roller 1a is located above the tooth portion 2b of the feed dog 2 and its width is substantially the same as the width of the tooth portion 2b. However, the width of the roller 1a may vary depending on the sewing conditions.
It is also possible to have a size that covers the entire width of the tooth portions 2a, 2b, 2c.

It is preferable that the rollers 1a and the feed dogs 2 are formed with teeth having the same pitch or an integral multiple pitch with each other. However, depending on the sewing conditions, both may be left flat without teeth, or knurled. It may be eye-shaped or made of rubber. The point is that any material can be used as long as it produces a frictional force with the cloth,
A greater effect can be obtained by selecting the material and surface shape of the roller 1a and the feed dog 2 that are optimal for the sewing conditions.

As shown in FIG. 1, when the roller base 1c is in the lowered position and the roller 1a projects from the lower surface of the presser foot 1b, during the cloth feeding movement, the tooth portions 2a, 2c.
Comes into contact with the presser foot 1b through the cloth, and the tooth portion 2b comes into mesh with the roller 1a through the cloth.

However, the roller 1a is held by the presser foot 1b.
If it protrudes from the lower surface of the
May hinder the sewing, and as shown in FIG. 3, it may be difficult to sew the cloth 4 while rotating the cloth 4 with a small radius.

In this case, as shown in FIG. 4, if the roller base 1c is raised and the roller 1a is retracted from the lower surface of the presser foot 1b so as to be flush with the lower surface of the presser foot 1b or have a slight clearance C. Good.

In this case, as shown in FIG. 5, it is necessary to provide a groove 1g on the lower surface of the presser foot 1b. The starting position D of the groove 1g may be on either the left or the right with respect to the needle drop portion 1c.

In the feed dog 2 in this case, as shown in FIG. 6, it is necessary to make the height of the tooth portion 2b higher than the height of the tooth portions 2a and 2c to provide the step E. Also, the groove 1 of the presser foot 1b
It is desirable that the depth F of g and the step E of the tooth portion be substantially the same, but depending on the type of the sewn product, a larger effect can be obtained by slightly changing it.

Even when the presser foot 1 and the feed dog 2 are used, the relationship between the presser foot 1 and the feed dog 2 is the same as that shown in FIG. Further, in this case, since the roller 1a does not project from the lower surface of the presser foot 1b, it is possible to smoothly perform curvature sewing with a small radius as shown in FIG.

FIG. 7 is a view showing the relationship between the tooth portions 2a, 2b, 2c of the feed dog 2 and the stitch 5 in the sewing state. In the conventional cloth feeding device, the relationship between the tooth portion 2a and the presser foot 1b or the relationship between the tooth portion 2c and the presser foot 1b in FIG. Sent. However, in the cloth feeding device of the present invention including the roller 1a, as shown in FIG.
Also, the lower cloth 4b is completely sandwiched between the roller 1a and the tooth portion 2b, and two sheets are fed at the same time.

At the position of the tooth portion 2b, the cloth 4 is sandwiched between the roller 1a and the cloth 4 and fed, while the tooth portion 2a,
At the position of the tooth portion 2c, those tooth surfaces and the presser foot 1b are
Since the cloth feed force is generated by the friction on the lower surface, the cloth feed amount in the tooth portion 2b is larger than the feed amount in the tooth portions 2a and 2c. Therefore, in the sewing in the present invention, as shown in FIG. 9, only the cloth at the tooth portion 2b position is strongly pulled. However, as shown in FIG. 10, the cloth 4 sewn in the stretched state has its distortion released after sewing and is restored, puckering does not occur, and the seams themselves have a soft and fluffy feel. Moreover, the knot point H between the upper thread 6a and the lower thread 6b is firmly determined in the stretched state of the cloth 4, and even if the stretched state of the cloth 4 is restored, the position does not change.

To reiterate, in the conventional cloth feeding device having no roller in the presser, if the friction constant of the lower surface of the presser foot is large, the force for feeding the upper cloth is lost and the cloth feeding device does not function. In the present invention, the large frictional force of the roller 1a in the presser 1 exerts a great effect of ensuring the cloth feeding.

In a sewing machine without back stitching, if a one-way clutch is used for the shaft 1f to prevent reverse rotation, a greater effect can be exhibited.

[0024]

Since the present invention is configured as described above, it has the following effects.

That is, since the upper and lower cloths are completely sandwiched between the roller and the feed and are fed at the same time, the sewing machine itself has exactly the same usability as the conventional one, and no drive source is required. Crimping and puckering no longer occur when sewing thin materials. Then, the knot points of the upper thread and the lower thread are firmly determined, and a soft seam can be obtained. Further, when the roller is not projected below the lower surface of the presser foot, curvature sewing with a small radius can be smoothly performed.

[Brief description of drawings]

FIG. 1 is a side view of a cloth feeding device according to the present invention.

FIG. 2 is a diagram showing a relationship between a presser roller and each tooth portion of a feed dog in the cloth feeding apparatus of the present invention.

FIG. 3 is a plan view showing a state of curvature sewing by the cloth feeding device of the present invention.

FIG. 4 is a side view of the cloth feeding device of the sewing machine of the present invention which employs a presser having a roller raised from the lower surface of the presser.

5A and 5B are views of a holding portion in the cloth feeding device shown in FIG. 4, in which FIG. 5A is a bottom view and FIG.

6A and 6B are views of feed dogs in the cloth feeding apparatus shown in FIG. 4, where FIG. 6A is a plan view and FIG.

FIG. 7 is a plan view showing a sewing state by the cloth feeding device.

FIG. 8 is a side view showing a state of the cloth at the feed roller position.

FIG. 9 is a plan view showing an actual sewing state by the cloth feeding device of the present invention.

FIG. 10 is a cross-sectional view showing a state of the sewn cloth by the cloth feeding apparatus of the present invention.

FIG. 11 is a side view of a conventional cloth feeding device.

FIG. 12 is a cross-sectional view showing a state of a sewn cloth by a conventional cloth feeding device.

[Explanation of symbols]

 1 Presser 1a Roller 1b Presser foot 1c Needle drop part 1h Bolt (position adjusting means) 2 Feed tooth (feed) 2a Tooth (feed) 2b Tooth (feed) 2c Tooth (feed)

Claims (8)

[Claims] 1. A cloth feed device for a sewing machine, which comprises a feed bar and a presser provided with a roller which is rotated by an elliptical motion of the feed bar behind a needle drop portion of a presser foot. 2. The cloth feed device for a sewing machine according to claim 1, wherein each of the feed bar and the roller has a surface for generating a frictional force between the feed bar and the roller. 3. The cloth feed device for a sewing machine according to claim 1, wherein the feed bar and the roller are provided with teeth having the same pitch or an integer multiple pitch. 4. The cloth feed device for a sewing machine according to claim 1, wherein the position of the roller can be adjusted in the vertical direction by the position adjusting means. 5. The cloth feed device for a sewing machine according to claim 1, wherein the roller can freely rotate in either direction. 6. The sewing machine according to any one of claims 1 to 5, wherein the feed has a plurality of rows of feed portions, and the roller is located above the central feed portion and has a width substantially equal to that of the feed portion. Cloth feeding device. 7. The cloth feed device for a sewing machine according to claim 6, wherein the roller protrudes below the lower surface of the presser foot, and the upper surfaces of the respective feed portions have the same height. 8. The sewing machine according to claim 6, wherein the roller does not protrude below the lower surface of the presser foot, a groove is formed in the lower surface of the presser foot, and the upper surface of the central feeding portion is higher than the upper surfaces of both feeding portions. Cloth feeding device.