KR101974869B1 - Sewing machine for controlling upper thread - Google Patents

Abstract

In the present invention, when a fabric moving frame moves in a front direction of a needle, the friction can be greatly reduced when an upper thread is in contact with a needle lower portion and a sharp needle tip, or to avoid contact between the needle lower portion and the upper thread. Accordingly, the present invention can accurately form stitches during sewing and greatly reduce single yarn.

Description

[0001] SEWING MACHINE FOR CONTROLLING UPPER THREAD [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine such as a sewing machine and an embroidery machine, and particularly to a sewing machine having a far-end frame driving device for moving a far-end moving frame in the X direction and / or the Y direction.

Generally, sewing machines are collectively referred to as sewing machines and embroidery machines.

In the sewing machine, there is a conventional sewing machine in which an operator completes the sewing work by directly moving the fabric, and in recent years, there is a sewing machine for sewing a sewing machine by attaching a fabric moving frame moving in both X and Y directions.

The present invention relates to a recent sewing machine or an embroidery machine equipped with a far-end moving frame movable in the X direction and / or the Y direction, not on a conventional sewing machine in which an operator directly moves a fabric.

The conventional technique will be described on the basis of a multi-head type embroidery machine having a plurality of sewing heads as one type of sewing machine.

1 is a structural view of a multi-head type computerized embroidery machine.

1, a thread of a thread spool 1 provided on an embroidery machine is connected to a thread take-up lever 6 and a needle (not shown) via a head 12 of an embroidery machine. 14, the needle 14 and the upper thread pass through the fabric, and the knot is formed by intersecting the lower thread unwound from the lower thread thread 16. The formation of the embroidery pattern is performed by driving a far-end moving frame 15 having a fabric fixed thereto by a far-end moving frame driving device including an X-axis driving motor and a Y-axis driving motor and forming a series of continuous knots To form a pattern created by computer.

The quality of the embroidery is related to the suitability of the tension to form a continuous knot. If the tension is small, it forms a loose pattern, and if the tension is too large, the knot is too hard and the thread tends to be broken in the embroidery process.

Fig. 2 is a view showing a tension adjusting system for a general thread of an embroidery machine.

The tension control system of a general thread of an embroidery machine can be roughly described as follows. A thread from a thread spool 1 is temporarily tensioned through a pre-tensioner 2 as shown in FIG. 2, tensioner 3 and then through a spring hook 4 to a needle bar case 5 and to the needle bar case 5, To a take-up lever 6 and a needle 14 which are mounted on a support shaft. The thread of the thread take-up lever 6 at this time is an upper thread 21 which is caught by the needle 14 through a lower thread guide 7 and is engaged with an under thread bobbin Stitches on fabric 30 by using a presser foot 10 together with an under thread unwound from the rollers 16. Therefore, in the embroidery process, the embroidery machine increases the tension applied to the yarn due to various factors, and if the tension is not solved, the yarn breaks. After embossing, the embroidery machine must be temporarily stopped and the yarn must be re-embroidered again, so that the production time is wasted in a large amount, the production efficiency is lowered, and the quality of the needle stitch is deteriorated.

Describing a problem in which the upper thread passing through the needle hole of the needle due to the movement of the fabric moving frame among the single threading problems is brought into contact with the lower needle portion (the portion from the needle hole to the needle tip) and the pointed needle tip, do.

FIG. 3 is a view showing the synchronized movement of a needle and a presser foot mounted on a needle bar interlocked with the rotation of a spindle motor, and FIG. 4 is a view showing a speed of a far-end moving frame moving in X and Y directions in association with a spindle motor .

3, in the mutual relation between the needle and the presser foot, the vertical reciprocating movement of the needle bar with the needle attached thereto is synchronized with the main shaft, and likewise, the presser foot also operates in conjunction with the main shaft motor. That is, when the needle is lifted away from the fabric, the presser foot is also raised synchronously.

3 and 4, when the needles and the presser foot are separated from the needle plate to the upper portion (around the main axis rotation angle of 270 degrees), the far-end moving frame starts to move, and the needle- And the needle reaches the bottom dead center after passing through the fabric at the main shaft rotation angle of 90 degrees (the movement of the far-end moving frame is stopped at this rotation angle). As the needle rises from the bottom dead center, To form a knot.

That is, when the needle bar and the presser foot are separated from the fabric upper part, the fabric moving frame moves in the X direction and / or the Y direction, and then forms the needle sweat at the next point.

5 is a plan view showing the moving direction of the far-end moving frame with respect to the position of the needle. As shown in FIG. 5, the far-end moving frame associated with the main axis around the needle 14 can be moved in the X direction and / or the Y direction so that the fabric fixed to the far-end moving frame moves in the X direction and / .

When the needle bar with the needle and the presser foot rise, it is set in the -Y direction when the fabric moving frame moves in the front direction of the needle, and it can be set in the + Y direction when the fabric moving frame moves in the back direction of the needle.

6 and 7 are views showing the state of the needle and the upper thread when the far-end moving frame moves in the back or front direction of the needle.

When the far-end moving frame and the fabric 40 fixed thereto move in the + Y direction (rear direction of the needle) as shown in Fig. 6, the upper thread 21 is not in contact with the needle lower end portion 14c.

Here, the needle lower end portion 14c refers to a portion of the needle 14 from the needle eye 14a to the needle tip 14b.

The upper thread 21 extending downward from the upper portion of the needle 14 into the needle hole 14a in the front direction of the needle 14 and extending in the rear direction of the needle 14 and connected to the lower end 40, .

However, when the far-end moving frame and the fabric 40 fixed thereto move in the -Y direction (the front direction of the needle) as shown in Fig. 7, the upper thread 21 moves in the direction of the needle lower end 14c Or the upper thread 21 is contacted with the pointed needle tip 14b and the upper thread is damaged, so that the possibility of occurrence of single yarn becomes very high.

7, the needle 14 is moving upward and the fabric 40 is moving in the -Y direction. Thus, in a state in which the upper thread 21 is in contact with the needle lower end 14c, It is easy to expect that the friction becomes larger as time elapses due to sliding on the lower end 14c.

That is, the movement of the far-end moving frame in the -Y direction (movement of the needle in the front direction) increases the friction between the needle and the yarn to increase not only the tension of the yarn but also the single yarn, which adversely affects the needle sweat, .

Further, since the recent sewing machine requires a faster rotation speed of the main shaft in order to improve the productivity, the speed of the fabric moving frame and the speed of the needle bar associated with the sewing machine must be further increased. Therefore, problems caused by the friction between the needle and the upper thread .

On the other hand, techniques for controlling the tension of the upper thread have been proposed in the prior art.

However, most of these conventional techniques are located above the needle case to adjust the tension of the upper thread, which can not solve the problem of increasing the tension of the upper thread, which occurs at the lower end of the needle (from the needle hole to the needle tip).

That is, the frictional force generated at the lower portion of the needle differs depending on the formation direction of the stitch (the moving direction of the far-end moving frame), so that the upper tension adjusting portion, which is conventionally attached to the needle bar case or formed at the upper end portion, , The frictional force generated at the lower end of the needle can not be controlled.

Further, it has been recognized that the contact between the needle and the upper thread occurring at the needle lower end portion and the needle tip occurs at a position very close to the fabric, so that it is almost impossible to control the contact occurring at the needle portion. All adjustment methods have been proposed to control the tension of the upper thread located above the needle eye.

In US Pat. No. 6,840,185, "METHOD AND SYSTEM FOR PREVENTING THREAD BREAKAGE" (registered on January 11, 2005), the tension of the upper thread was controlled by controlling the movement path of the fabric moving frame. However, the design of the embroidery pattern is very complicated There is a problem that it is difficult to completely determine a path that can avoid the single yarn phenomenon in advance.

Korean Registered Utility Model No. 20-0437917 "Tension regulating device of embroidery machine" (Registered on December 29, 2007) US Patent 6,840,185 " METHOD AND SYSTEM FOR PREVENTING THREAD BREAKAGE " (registered on January 11, 2005)

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems of the prior art as described above, and it is an object of the present invention to provide an apparatus and a method for manufacturing a needle- And to avoid contact between the needle lower part and the upper thread.

The contact between the upper thread and the needle at the lower end of the needle and the tip of the sharp needle not only generates a single thread of the upper thread but also has a large influence on the formation of the needle stitch. .

According to an aspect of the present invention, there is provided a needle bar comprising: a needle bar equipped with a needle having a needle hole through which an upper thread passes; A presser foot which is formed at a lower portion with a hole forming portion formed with a presser foot hole through which the needle passes, and is vertically reciprocable; A fabric moving frame provided movably in a direction orthogonal to an extension line of the needle while the fabric is fixed to move the fabric; The upper end of the upper thread located between the needle tip of the needle and the far end moving frame is prohibited from moving in the front direction of the needle or the upper end of the upper thread located between the needle tip of the needle and the far- An upper thread front direction movement limiting and releasing device capable of restricting movement of the upper thread in the front direction or releasing restriction of movement of the upper thread in the front direction while moving the upper thread in the direction of the upper thread; Wherein the upper thread front direction movement limiting and releasing device moves the presser foot passing through the upper thread toward the back face of the needle so that the hole forming part of the presser comes into contact with the upper thread, Is limited.

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When the upper thread front direction movement restriction and release device removes a force applied to the presser foot, the presser foot is restored to a position spaced apart from the upper thread by elasticity, .

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The upper thread front direction movement limiting and releasing device may include a cam structure rotating bar having a cam structure and in contact with the presser foot, a driving motor rotating the cam structure rotating bar, And a motor control unit for controlling the rotation of the driving motor in accordance with the rotational position of the spindle motor input to the spindle motor rotational position input unit.

As described above, according to the present invention, when the far-end moving frame moves in the front direction of the needle, the friction when the upper thread comes into contact with the lower needle tip and the sharp needle tip can be greatly reduced or the contact between the needle lower portion and the upper thread can be avoided.

Accordingly, the present invention can accurately form stitches during sewing and greatly reduce single yarn.

1 is a structural view of a multi-head type computerized embroidery machine,
Fig. 2 is a view showing a tension adjusting system of a general thread of an embroidery machine,
3 is a view showing the synchronized movement of a needle and a presser foot mounted on a needle bar interlocked with the rotation of a spindle motor,
Fig. 4 is a view showing the speed of a far-end moving frame linked to the spindle motor and moving in X and Y directions,
5 is a plan view showing a moving direction of the far-end moving frame with respect to the position of the needle,
6 and 7 are views showing a state diagram of a needle and an upper thread when the far-end moving frame moves in the back or front direction of the needle,
8 is a configuration diagram of an upper thread front direction movement restriction and release device according to the first embodiment of the present invention,
9 is a perspective view of a main portion of a sewing machine according to the first embodiment of the present invention,
FIG. 10 is a view showing a state in which the upper structure is moved in the rear direction by pushing the presser foot of the cam structure rotating bar of the upper thread front direction movement restriction and release device in FIG. 9,
11 is a view showing a state in which the upper thread is returned to the original position while the rotary bar of the cam structure of the upper thread front direction movement restriction and release device is separated from the presser,
12 is a view showing a state in which the upper thread is moved in the rear direction according to the second embodiment of the present invention,
13 is a view illustrating a state in which the upper thread is moved in the rear direction according to the third embodiment of the present invention,
FIG. 14 is a view showing a state in which the upper thread is moved in the rear direction according to the fourth embodiment of the present invention. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention in the drawings, portions not related to the description are omitted, and like reference numerals are given to similar portions throughout the specification.

Throughout the specification, when an element is referred to as " comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

9 is a perspective view of a main portion of a sewing machine according to the first embodiment of the present invention, and FIG. 10 is a perspective view of the upper thread portion of the upper thread 11 shows a state in which the upper structure is shifted in the rear direction by pushing the presser foot, and FIG. 11 is a state in which the cam structure rotary bar of the upper thread front direction movement restriction and release device is spaced from the presser foot And the upper thread is returned to the original position.

The sewing machine of the present embodiment mainly includes a needle bar 100 on which a needle 110 is mounted, a presser foot 200, a far-end moving frame (not shown), and an upper-

A needle 110 is mounted on the needle bar 100, and the needle bar 100 reciprocates up and down synchronously with the rotation of the main shaft motor.

A needle hole 111 is formed in a horizontal direction at a lower portion of the vertically disposed needle 110 and a pointed needle tip 112 is formed at the lowermost end of the needle 110.

The needle 110 in the needle 110 and the needle tip 112 are referred to as the needle lower end 113.

The presser foot 200 reciprocates vertically in synchronism with the rotation of the spindle motor as in the case of the needle bar 100. A presser foot hole 210 for allowing the needle 110 and the upper thread 510 to pass therethrough is formed at a lower portion of the presser foot 200, Hole forming portion 220 is formed.

The presser foot 200 is mounted on the needle bar 100 synchronized with the rotation of the spindle motor through a spring so as to perform up and down reciprocating movement by spring elasticity when the needle bar 100 is reciprocated upward and downward.

However, the presser foot 200 may be designed to operate in conjunction with the movement of the needle bar with a presser foot drive motor.

The fabric moving frame (not shown) is provided to move the fabric 520 in a direction orthogonal to the extension line of the needle 110 (i.e., in a horizontal direction), and is a portion where the fabric 520 is fixed.

A far-end moving frame driving device (not shown) is provided for moving the far-end moving frame. As described above, the far-end moving frame and the fabric 520 fixed thereto are moved in the X direction and / or the Y direction . ≪ / RTI >

The upper thread chamber forward movement restriction and release device 400 is rotated in synchronization with the rotation of the spindle motor so that the needle tip 112 of the needle 110 and the distal movement frame (strictly speaking, the fabric 520) To limit the movement of the upper thread 511 located between the upper needle 511 and the upper needle 511 in the front direction of the needle, or to release the restriction.

The limitation of movement of the needle in the front direction relative to the upper thread 511 is such that when the needle tip 112 of the needle 110 is spaced from the upper portion of the far-end moving frame (strictly, the upper portion of the fabric 520) The upper end of the upper thread 511 located between the needle tip 112 of the needle 110 and the fabric moving frame (strictly speaking, the fabric 520) is prevented from moving in the front direction of the needle, (That is, moving in the lateral direction with respect to the extending direction of the upper thread 511).

In addition, release of the limitation of movement of the upper thread in the front direction is accomplished by releasing restriction on the upper thread (inhibition of movement in the front direction or movement in the rear direction).

The upper thread chamber direction movement restriction and release device 400 may be configured as shown in FIG.

More specifically, the upper thread chamber direction movement restricting and releasing device 400 includes a cam structure rotating bar 410 having a cam structure for moving the upper thread 510, a driving motor 420 for rotating the cam structure rotating bar 410, A spindle motor rotational position input unit 430 for receiving the rotational position of the spindle motor and a rotational motor 430 for rotationally controlling the driving motor 420 in accordance with the rotational position of the spindle motor input to the spindle motor rotational position input unit 430 And a motor control unit 440.

The cam structure rotatable bar 410 has the same cross sectional structure and extends in the longitudinal direction and rotates about the rotation axis 411. The cross sectional structure is a cam that changes the distance from the rotation axis 411 along the main surface, Structure.

The sewing machine having the upper thread front direction movement limiting and releasing device 400 repeats the step of restricting the movement of the upper thread front direction in conjunction with the rotation of the spindle motor and the step of releasing the upper thread front direction restricting restriction.

The upper thread movement limiting step may be performed such that when the needle tip 112 of the needle 110 moves upward after passing through the far end moving frame and the tail 520 as in the present embodiment, And moving the upper end of the upper thread 511 located between the distal end moving frame and the distal end moving frame in the back direction of the needle.

However, according to the embodiment, the step of restricting the movement of the upper thread 511 may prevent the upper end of the upper thread 511 from moving in the front direction without moving the upper end of the upper thread 511 toward the back side of the needle.

Even when the far-end moving frame and the tail 520 are moved in the -Y direction (the front direction of the needle 110) by the above-described upper thread movement restriction step, the needle lower end 113 and the needle tip 112 The friction between the upper thread 511 and the upper thread 511 can be significantly reduced and further the contact between the lower thread 113 and the upper thread 511 can be avoided.

As described above, the fabric moving frame and the fabric 520 are moved in contact with each other to avoid contact between the needle lower end portion 113 and the upper thread 511 or reduce friction, The movement of the far-end moving frame and the tail 520 is stopped by the releasing step, and the restriction on the upper thread 511 is released so that the upper thread 511 is freely stretched.

The upper thread front direction movement restriction releasing step may be performed such that the needle 110 passes the top dead center and the needle tip 112 of the needle 110 moves downward to pass through the far- The upper limit of the upper thread 511, which has been moved in the backward direction (or is prohibited from moving in the front direction), is released by the upper thread front direction movement limiting step. Thereby, the upper thread 511 is freely stretched.

The upper thread front direction movement restricting step and the upper thread front direction movement restricting step are performed by the upper thread front direction movement restricting and releasing device 400. The upper thread front direction movement restricting and releasing device 400 is directly connected to the upper thread 511 To restrict the movement of the upper thread 511 in the front direction or to move the presser foot 200 through the upper thread 511 in the direction of the back face of the needle 110 so that the presser foot 200 comes into contact with the upper thread, Can be indirectly limited.

Will be described in more detail with reference to Figs. 9 to 11. Fig.

The upper thread chamber direction movement limiting and releasing device 400 is configured such that the driving motor 420 rotates the rotation axis 411 of the cam structure rotation bar 410 and the cam structure rotation bar 410 rotates about the rotation axis 411 The presser foot 200 is rotated in the same position and the presser foot 200 is pushed as shown in FIG. 10 or is separated from the presser foot 200 as shown in FIG.

10, the portion 511 between the needle tip 112 and the fabric 520 in the upper thread 510 passes through the presser foot hole 210 formed in the presser foot 200, The top end of the upper thread 511, which is in contact with the presser foot 200, moves in the backward direction of the needle.

That is, when the needle 110 is lifted, the cam structure rotating bar 410 having the cam structure rotates to move the presser foot 200 in the rear direction of the needle 110, so that the presser foot 200 having the presser foot hole 210 The upper end of the upper thread 511 is moved in the back direction of the needle so that the lower end of the upper thread 511 fixed to the fabric 520 moves toward the front side of the needle, It is possible to prevent the upper thread 511 from coming into contact with the needle lower end portion 113 even though it moves in the front direction of the needle.

When the cam structure rotating bar 410 further rotates and is separated from the presser foot 200 as shown in FIG. 11 (that is, when the cam structure rotating bar 410 removes the force exerted on the presser foot 200), the presser foot 200 And the upper thread 511 is also separated from the presser foot 200, thereby releasing the front direction movement restriction.

The cam structure rotating bar 410 having the cam structure is rotated just before the needle 110 passes through the presser foot hole 210 of the presser foot 200 so that the needle 110 is pressed against the presser foot hole 210 of the presser foot 200, And returns the position of the presser foot 200 so that the presser foot 200 can penetrate the fabric 520.

As described above, according to the present embodiment, when the presser foot 200 which is vertically reciprocatingly moved upwards from the fabric 520, the presser foot 200 is moved in the horizontal direction, in particular, in the back face direction of the needle, thereby avoiding contact between the upper thread and the needle, So that the single yarn can be prevented, and as a result, the productivity of the sewing improves.

Meanwhile, the presser foot 200 is mounted on the needle bar 100 with elasticity. When the presser foot 200 is pressed by the cam structure rotating bar 510, the presser foot 200 moves backward. Position.

That is, in this embodiment, when the upper thread front direction movement restriction and release device 400 presses the presser foot 200, the presser foot 200 is moved to the upper thread 511 by using the elasticity of the presser foot 200, In the upper thread chamber front direction movement restriction releasing step, the presser foot forward movement restricting and releasing device 400 does not press the presser foot 200, so that the presser foot 200 returns to its original position, The restriction is released.

However, according to the embodiment, the presser foot 200 may be freely moved, and the upper thread chamber direction movement restriction and release device 400 may be configured to move the presser foot 200 in the upper thread chamber front direction movement restriction step and the upper thread chamber front direction movement restriction release step, It is possible to freely change the position of the display device.

12 is a view showing a state in which the upper thread is moved in the rear direction according to the second embodiment of the present invention.

In this embodiment, the cam structure rotating bar 410 of the upper thread front direction movement limiting and releasing device 400 is configured to push the hole forming part 220 of the presser foot 200.

That is, it can be seen that the cam structure rotating bar 410 of the upper thread front direction movement limiting and releasing device 400 can be provided at various portions of the presser foot 200.

FIG. 13 is a view showing a state in which the upper thread is moved in the backward direction according to the third embodiment of the present invention. FIG.

In this embodiment, the cam structure rotating bar 410 of the upper thread front direction movement restriction and release device 400 simply prohibits the upper end of the upper thread 511 from moving in the front direction. That is, in this embodiment, the upper end of the upper thread 511 is not moved in the rear direction of the needle by the cam structure rotating bar 410, but merely the movement in the front direction is restricted.

FIG. 14 is a view showing a state in which the upper thread is moved in the backward direction according to the fourth embodiment of the present invention. FIG.

In this embodiment, the cam structure rotating bar 410 of the upper thread front direction movement restriction and release device 400 is configured to directly move the upper end of the upper thread 511.

At this time, the cam structure rotating bar 410 of the upper thread front direction movement limiting and releasing device 400 is disposed between the presser foot 200 and the cloth 520 to move the upper end of the upper thread 511 in the back direction of the needle.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the embodiments described above are intended to be illustrative, but not limiting, in all respects. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: Needle bar
110: Needle 111: Needle hole
112: needle tip 113: needle lower portion
200: presser foot 210: presser foot hole
220: hole forming part
400: Limiting and releasing movement of the upper thread in the front direction
410: cam structure rotating bar 411: rotating shaft
420: drive motor 430: spindle motor rotation position input section
440: Motor control section
510, 511: upper thread
520: Fabric

Claims (6)

A needle bar equipped with a needle having a needle hole through which an upper thread passes, and being capable of reciprocating up and down;
A presser foot which is formed at a lower portion with a hole forming portion formed with a presser foot hole through which the needle passes, and is vertically reciprocable;
A fabric moving frame provided movably in a direction orthogonal to an extension line of the needle while the fabric is fixed to move the fabric;
The upper end of the upper thread located between the needle tip of the needle and the far end moving frame is prohibited from moving in the front direction of the needle or the upper end of the upper thread located between the needle tip of the needle and the far- An upper thread front direction movement limiting and releasing device capable of restricting movement of the upper thread in the front direction or releasing restriction of movement of the upper thread in the front direction while moving the upper thread in the direction of the upper thread;
And,
The upper thread movement limiting and releasing device moves the presser through the upper thread toward the back side of the needle so that the hole forming part of the presser comes into contact with the upper thread to indirectly limit the upward movement of the upper thread. Sewing machine.
The method according to claim 1,
Wherein when the force exerted on the presser foot by the upper thread front direction movement restraining and releasing device is removed, the presser foot is restored to a position spaced apart from the upper thread by elasticity, thereby releasing restriction of movement of the upper thread in the front direction.
The method according to claim 1,
The upper thread front direction movement restricting and releasing device includes a cam structure rotating bar having a cam structure and in contact with the presser foot, a driving motor for rotating the cam structure rotating bar, a spindle motor for receiving a rotating position of the spindle motor, And a motor control unit for controlling the rotation of the drive motor in accordance with the rotational position of the spindle motor input to the spindle motor rotational position input unit.
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