JP2001187288A - Cloth presser apparatus of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cloth presser apparatus of a sewing machine which can follow the high-speed operation of the sewing machine with an inexpensive device, and prevent the jumping of a cloth presser caused by a feed dog. SOLUTION: The cloth presser apparatus of the sewing machine comprises connection members 11, 12, 13 connected to a spindle of the sewing machine and oscillated on one end side, a moving member 19 to be vertically moved accompanied by the oscillation of the connection members, and an elastic member 21 with one end thereof engaged with the moving members and the other end thereof engaged with a presser bar, and the feed dog lower the moving member so that the urging force of the elastic member is larger when the feed dog is elevated higher than a throat plate than when the feed dog is positioned below the throat plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a presser foot device for a sewing machine, and more particularly to a presser foot device for a sewing machine which feeds a cloth (sewing material) in cooperation with a presser foot and a feed dog. .

[0002]

2. Description of the Related Art Conventionally, as a sewing machine presser of this type, one described in Japanese Patent Application Laid-Open No. 11-19358 is known. This device uses a coreless motor as a pressing force applying means for applying a pressing force to the cloth presser. Then, the control current for torque adjustment is controlled in accordance with the rotation speed of the sewing machine to vary the pressure of the presser foot. By increasing the pressure of the presser foot with an increase in the rotation speed of the sewing machine, a jumping phenomenon of the presser foot due to a collision between the presser foot and the feed dog is prevented.

[0003]

However, the conventional presser foot device of the sewing machine electrically controls the torque of the coreless motor so as to control the pressure of the presser foot. When a general-purpose coreless motor is used, there is a problem that the torque control cannot follow the mechanical movement of the work clamp when the sewing machine rotates at a high speed. Further, when a general-purpose coreless motor is used, a problem also arises in terms of durability.

[0004] In order to solve the problems of high-speed followability and durability, a custom-made coreless motor must be used, causing a problem that the apparatus and its control equipment become expensive.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can follow a high-speed operation of a sewing machine with an inexpensive device, and can prevent jumping of a presser foot by a feed dog. An object of the present invention is to provide a presser foot device for a sewing machine.

[0006]

In order to solve the above-mentioned problems, the present invention is directed to a needle bar which moves up and down in conjunction with a main shaft of a sewing machine, and a feed bar which performs four feed movements in conjunction with a main shaft of the sewing machine. Presser bar (23) supported by the teeth (26) and the sewing machine frame so as to be vertically movable and having a cloth presser (24) attached to the lower end.
In the presser foot device of a sewing machine, wherein the feed dog and the presser cooperate to send a sewing product, the feed dog and the presser foot are connected to a main shaft of the sewing machine,
A connecting member (11, 12, 13) that swings, a moving member (19) that moves up and down as the connecting member swings, and a moving member (19) that is disposed between the moving member and the presser bar. An elastic member (21) whose elastic force applied to the presser bar is changed by the movement, wherein when the feed dog is higher than the needle plate than when the feed dog is located below the needle plate, The moving member is moved so that the biasing force of the elastic member is increased.

According to the first aspect of the present invention, since the urging force can be mechanically varied in conjunction with the main shaft of the sewing machine, it is possible to easily follow the high-speed operation of the sewing machine. Further, since the urging force of the elastic member is increased when the feed dog is raised above the needle plate, jumping of the presser foot by the feed dog can be prevented. Further, since the feed dog and the presser cooperate to reliably send the sewn material, it is possible to prevent the occurrence of sewing-like defects such as cuts. Further, since a motor and its control device are not used, an inexpensive and reliable cloth presser is provided.

According to a second aspect of the present invention, in the presser device of the first aspect, the urging force of the elastic member is increased or decreased along a feed dog elevation curve (H) of the feed dog. . According to the second aspect of the present invention, since the urging force against the presser foot becomes appropriate, jumping of the presser foot by the feed dog can be more reliably prevented.

According to a third aspect of the present invention, in the sewing machine of the first aspect, the moving member is connected to a swing end side of the connecting member, and the relative position of the moving member with respect to the connecting member is determined. Changeable first adjusting means (18, 1
9, 25).

[0010] According to the third aspect of the invention, the initial setting position of the moving member can be changed by the first adjusting means. Therefore, according to the sewing conditions (material, cloth thickness, etc.),
By adjusting the biasing force, a predetermined seam is formed.

According to a fourth aspect of the present invention, in the sewing machine of the first aspect, the connecting member includes a plurality of links (11, 12, 13), and a connecting position between the links is adjusted. A configuration is provided with a possible second adjusting means (11, 17).

According to the fourth aspect of the present invention, the predetermined adjusting force can be obtained by displacing the amount of vertical movement of the moving member by the second adjusting means.

According to a fifth aspect of the present invention, in the sewing machine presser holding apparatus according to the fourth aspect, the second adjusting means extends along an arc (Y) centered on one connection point (12b) of the link. , And can be moved.

According to the fifth aspect of the present invention, since the value of the initial setting value (minimum urging force) does not change, adjustment of the urging force can be performed more easily.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a front view of a first embodiment of the present invention, FIG. 2 is a side view of the first embodiment, and FIG. 3 is an exploded perspective view of the first embodiment. FIG. 4 is a characteristic diagram showing the relationship between the amount of displacement of the feed dog and the biasing force of the presser foot in the first embodiment, and FIG. 5 is an explanatory diagram of the biasing force adjusting method of the first embodiment.

In the sewing machine frame 1 of FIG. 1, a well-known upper shaft (main shaft) 2 is arranged. On the surface side of the upper shaft 2,
A needle bar (not shown) is connected via a needle bar crank rod and a needle bar holder, and the needle bar moves up and down in conjunction with the upper shaft 1.

As shown in FIG. 3, in the center of the upper shaft 2,
The eccentric cam 3 is fixed by a screw (not shown).

The connecting rod 4 includes a ring 4 provided at the base end.
a is fitted to the cam portion 3 a of the eccentric cam 3,
And a screw (not shown) so as to be rotatable with respect to the eccentric cam 3. A connecting shaft 8 arranged in parallel with the upper shaft 2 is rotatably supported by the sewing machine frame 1, and a base end of a connecting arm 6 is fixed to one end of the connecting shaft 6 via a thrust collar 9. . The connecting rod 4 and the connecting arm 6 are connected by screwing a screw end of a stepped screw 7 communicating with the hole 4b provided at the front end of the connecting rod 4 into a screw hole 6a provided at the front end of the connecting arm 6. I do. The eccentric cam 3, the connecting rod 4, the connecting arm 6, and the connecting shaft 8 constitute a converting member for converting the rotational movement of the upper shaft 2 into a swinging movement of a connecting member described later.

The other end 8 located on the side of the sewing machine face plate of the connecting shaft 8
b is fixed to the main body 11a of the adjustment link arm 11 via the thrust collar 10. The adjusting link arm 11 (connecting member) has an adjusting portion 11b projecting in the lateral direction, and the adjusting portion 11b is formed with an arc-shaped long hole 11c.

A support shaft 14 parallel to the upper shaft 2 is fixed to a support base 28 provided at the upper end of the sewing machine frame 1, and the support shaft 14 can rotate a central portion of a seesaw member (connecting member) 13. To support.

The link 1 is inserted into the elongated hole 11c of the adjusting link arm.
The one end 12a of the 2 (connecting member) is connected by the stepped screw 17 and the nut 17a so as to be adjustable in position along the elongated hole 11c. This adjustment link arm 11, step screw 17, nut 1
7a constitutes a second adjusting means.

The other end 12b of the link 12 is
The nut 16 and the nut 16 rotatably connect and support the screw hole 13 c at one end of the seesaw member 13.

The other end 13b of the seesaw member 13 has a bifurcated shape, and has grooves 13d, 13d formed on its side surface.
The pin 18 of the presser bar guide roller 18 is
a and 18a are fitted.

A female screw 1 is provided at the center of the holding rod guide roller 18.
8b is formed, and the male screw 19a of the movable presser bar 19 is screwed. The presser bar guide roller 18 is fixed at a predetermined position of the movable presser bar 19 by the nut 25 from above. The nut 25, the presser bar guide roller 18, and the moving presser bar 1
9 constitutes the first adjusting means. The relative position of the movable holding bar 19 with respect to the seesaw member 13 (connection member) can be changed by the first adjusting means.

The moving holding rod 19 (moving member) includes a screw portion 19a, a main body portion 19b, and a support portion 19c along the vertical direction.
Consists of The main body 19b is supported by a guide metal 20 fixed to the upper portion of the sewing machine frame so as to be slidable in the vertical direction.

Below the moving presser bar 19, a presser bar holder 2 is provided.
2 are provided. The presser bar holder 22 has a through hole 22a formed at the center and a horn-shaped protrusion 22b provided on the side surface. Although not shown in the drawings, the horn-shaped projections 22b of the presser bar holder fit into the vertical grooves of the sewing machine frame, and the presser bar holder 2
2 is supported slidably in the up-down direction.

The presser bar 23 has an upper portion formed with a hole 23a for loosely fitting the support 19c of the movable presser bar. Then, the presser bar 23 is passed through the through hole 22a of the presser bar holder, and is fixed to the presser bar holder 22 by a bolt (not shown) from the side female screw 22c. In addition, the holding bar holding 22
The guide metal 29 fixed to the sewing machine frame is supported in a vertically operable manner.

The compression spring (elastic member) 21 is supported by the supporting portion 19c of the moving presser bar. One end of the compression spring is engaged with the step 19d of the moving presser bar, and the other end is engaged with the presser bar 23. .

A presser foot 24 (cloth presser) is fixed to the lower end of the presser bar 23 by a screw 30. Below the presser foot 24, there is provided a feed dog 26 which makes a four-feed motion in conjunction with the main shaft of the sewing machine, and the feed dog 26 and the presser foot 24 cooperate to feed a sewing product.

Next, the operation of the first embodiment will be described.

When the upper shaft 2 of the sewing machine rotates, the connecting rod 4
The arm 6 swings in the p direction shown in FIG. 1, and the connecting shaft 8 rotates. The rotation of the connecting shaft 8 causes the adjusting link arm 11 to swing in the q direction. Then, through the link 12, the seesaw 1
3 swings in the r direction to move the moving member 19 in the vertical direction. Due to the vertical movement of the moving member, the spring 19 is compressed or released, and presses the sewn material clamped between the work clamp 24 and the feed dog 26.

The eccentric cam 3 fixed to the upper shaft 2 maintains the relationship shown in FIG. 4 by the urging force of the elastic member 21 due to the vertical movement of the moving member 19 via the connecting members (11, 12, 13). Is set to

A curve H in FIG. 4 (a) is a movement trajectory of the feed dog 26 when the feed tooth 26 rises above the upper surface of the needle plate 27, and a curve I represents an increase or decrease in the urging force of the elastic member 21. In addition,
The horizontal axis in FIG. 4 is the time T of the same coordinates.

As shown in FIG. 4, the feed dog 26 is
The urging force f of the elastic member 21 is always larger at the time t2 when the feed dog 26 is rising from the needle plate 27 than at the times t1 and t3 when the lower surface is located.

Further, the urging force f of the elastic member increases and decreases along the movement locus H of the feed dog. That is, when the feed dog 26 rises, the urging force f increases, and when it falls, the urging force decreases. As a result, jumping of the presser foot 24 due to the vertical movement of the feed dog 26 can be reliably prevented. Further, since the feed dog and the presser cooperate to reliably send the sewn material, it is possible to prevent the occurrence of sewing-like defects such as cuts. Further, at the time t0 when the needle pierces the cloth, the urging force f is reduced, so that the texture of the sewn product is good.

Also, the first adjusting means (18, 19, 25)
As a result, the moving member 19 with respect to the seesaw (connecting member) 13
When the relative position of is changed, the urging force shown in FIG.
The curve I changes to curves J1 and J2. This curve J1, J
2 is obtained by applying a predetermined urging force to the curve I and translating the curve I up and down. Thus, the moving member 19
By increasing / decreasing the urging force f, an optimum urging force can be obtained according to the sewing conditions.

Next, the increase and decrease of the urging force when the connecting position between the adjusting link arm 11 and the link 12 is changed by the second adjusting means (11, 17) will be described with reference to FIGS.

The connecting members 11, 12, and 13 shown by dotted lines in FIG.
Reference numeral 13 denotes a position (initial position) where the needle bar is at the top dead center and the feed dog is lower than the needle plate, and the solid line connecting member is a position where the feed dog is at the highest point and the urging force f is maximum. Is shown.

As shown in FIG. 5, when the stepped screw 17 is located at the outermost end of the long hole 11c of the adjusting link arm and the link 12 is connected, the fluctuation width w of the urging force f of the presser foot is maximum. become. When the connecting position of the adjusting link arm 11 and the link 12 by the step screw 17 approaches the innermost diameter portion 11ca, the fluctuation width w of the urging force decreases and changes to a curve K shown in FIG.

When the connecting member is at the initial position, the tightening of the step screw 17 and the nut is loosened. At this time,
The step screw 17 supported on the other end side of the link 12 can swing about one connection point 12b (13c) of the link 12 as a fulcrum.

The long hole 11c of the adjustment link arm is formed so that the adjustment link arm 11 can be kept stationary by the swing of the other end of the link 12.

That is, at the initial position, the center of the elongated hole 11c of the adjusting link arm is pivotally movable about one connecting point 12b of the link 12 while maintaining the adjusting link arm 11 in a stationary state. It is formed along the arc Y of 12b. Therefore, it is possible to change only the fluctuation range of the urging force without changing the initial set value in the initial state.

The present invention can be variously modified without being limited to the above embodiment.

For example, in the above embodiment, the eccentric cam 3 and the connecting rod 4 fitted to the eccentric cam 3 are used.
Use of a connecting rod that engages with a triangular cam and performs a predetermined swinging motion, or uses a groove cam and a link whose center is rotatably supported and one end of which fits into the groove of the groove cam. It is easily conceivable.

The second adjusting means comprises the adjusting link arm 11, the link 12, and the stepped screw 17 between the seesaw 13 and the connecting shaft 8. Instead, the connecting rod 4 and the connecting shaft 8 are used. It can easily be provided between them.

Further, U-shaped grooves 13d, 13d in the forked portion of the seesaw 13 are inserted into both end shaft portions 18a, 1
8a is fitted, but instead of this, a square U-shaped square groove is formed in the seesaw bifurcated portion, and square sesame fitted into this square groove is fixed to both ends of the presser bar guide roller. Exercise of movement becomes faster.

[0047]

As described above, according to the sewing machine presser holding device according to the first aspect, the biasing force can be changed in conjunction with the main shaft of the sewing machine, so that the sewing machine can easily follow the high-speed operation of the sewing machine. it can. Further, since the urging force of the elastic member is increased when the feed dog is raised above the needle plate, jumping of the presser foot by the feed dog can be prevented. Further, since the feed dog and the presser cooperate to reliably send the sewn material, it is possible to prevent the occurrence of sewing-like defects such as cuts. Further, since a motor and its control device are not used, an inexpensive and reliable cloth presser is provided.

According to the second aspect of the present invention, in addition to the effect of the first aspect, the urging force against the presser foot becomes appropriate, so that jumping of the presser foot by the feed dog can be performed more reliably. Can be prevented.

According to the third aspect of the present invention, in addition to the effects of the first aspect, the initial setting position of the moving member can be changed by the first adjusting means.
For this reason, a predetermined seam is formed by adjusting the biasing force according to the sewing conditions (material, cloth thickness, etc.).

According to a fourth aspect of the present invention, in addition to the effect of the first aspect, the vertical movement of the moving member is displaced by the second adjusting means to obtain a predetermined urging force. be able to.

According to the sewing machine presser holding device of the fifth aspect, in addition to the effect of the fourth aspect, since the value of the initial setting value (minimum biasing force) does not change, adjustment of the biasing force is easier. Can be done.

[Brief description of the drawings]

FIG. 1 is a front view of a first embodiment.

FIG. 2 is a side view of the first embodiment.

FIG. 3 is an exploded perspective view of the first embodiment.

FIG. 4 is a characteristic diagram showing a relationship between a displacement amount of a feed dog and a biasing force of a presser foot in the first embodiment.

FIG. 5 is an explanatory diagram of a biasing force adjusting method according to the first embodiment.

[Explanation of symbols]

 26 feed dog 24 presser foot adjustment link arm (connecting member) 12 link (connecting member) 13 seesaw member (connecting member) H feed dog rise curve S 18. Presser rod guide roller (first adjusting means) 19 Moving member (first adjusting means) 25 Nut (first adjusting means) 11c Adjusting link arm elongated hole (second adjusting means) 17.・ Step screw (second adjusting means) 12b ・ ・ Connection point Y ・ ・ Arc

Claims (5)

[Claims] A needle bar which moves up and down in conjunction with the main shaft of the sewing machine; and a feed dog which performs four feed movements in conjunction with the main shaft of the sewing machine.
And a presser bar (23) supported on a sewing machine frame so as to be vertically movable and having a lower end provided with a cloth presser (24). The cloth of the sewing machine which feeds a sewing product in cooperation with the feed dog and the presser foot. In the presser device, the connecting member (11, 1) which is connected to the main shaft of the sewing machine and swings.
2, 13), and a moving member (19) that moves up and down as the connecting member swings.
And an elastic member (21) disposed between the moving member and the presser bar, the elastic force of which is applied to the presser bar changed by movement of the moving member, wherein the feed dog is lower than the needle plate Wherein the moving member is moved so that the urging force of the elastic member is increased when the feed dog is higher than the needle plate than when the feed dog is positioned at the position above. 2. A presser foot for a sewing machine according to claim 1, wherein the urging force of said elastic member increases or decreases along a feed dog elevation curve (H) of said feed dog. apparatus. 3. The sewing machine according to claim 1, wherein the moving member is connected to the swinging end of the connecting member, and the position of the moving member relative to the connecting member can be changed. A cloth presser for a sewing machine, comprising means (18, 19, 25). 4. A sewing machine presser holding device according to claim 1, wherein said connecting member comprises a plurality of links (11, 12, 13), and a second adjusting means capable of adjusting a connecting position between said links. (1
1, 17) is a presser foot device for a sewing machine. 5. The sewing machine presser foot device according to claim 4, wherein said second adjusting means includes one connecting point of a link (12b).
A presser foot apparatus for a sewing machine, which is movable along an arc (Y) centered on the sewing machine.