KR100561656B1 - Thread tension apparatus for sewing machine - Google Patents

Abstract

The tensioning device 1 of a thread for a sewing machine includes a tensioner 19 of a thread for applying tension to the upper thread and a driving means 60 that acts on the tensioner 19 of such thread to change the tension of the thread; The tension of the thread can be changed by controlling the amount of electricity supplied to the drive means 60. The stroke of the movable part 61 of the drive means 60 is S, the thrust of the movable part 61 is F, the amount of electricity supplied to the drive means 60 is C, and the amount of change of the stroke S and the thrust F is respectively. When DELTA S and DELTA F, the drive means 60 has the characteristic that DELTA F / DELTA S becomes substantially zero at least in the stroke S in a specific section under a constant electric quantity C. Moreover, the stroke S is set to a specific section. Therefore, the tensioning device 1 of the thread accurately controls the tension of the thread by using a solenoid instead of using an expensive voice-coil motor.

Description

Tension Device of Thread for Sewing Machine {THREAD TENSION APPARATUS FOR SEWING MACHINE}

1 is a perspective view of a sewing machine having a tensioning device of a thread embodying an aspect of the present invention.

2 is a side view of the tensioning device of the yarn of FIG.

3 is an exploded perspective view of the tensioning device of the yarn of FIG.

4 is a cross-sectional view showing a solenoid of a tension device of a thread.

5 is a graph showing the characteristics of the stroke versus thrust of the solenoid of FIG.

6 is a graph showing the characteristics of the current versus thrust of the solenoid of FIG.

7 is a block diagram showing a configuration of a control circuit of a sewing machine.

8 is a circuit diagram of a solenoid driver for driving the solenoid of FIG.

FIG. 9 shows an example of a buttonhole seam formed by a buttonhole sewing machine. FIG.

Explanation of symbols on the main parts of the drawings

1: Thread tensioner 19: Thread tensioner

21: operation panel 40: controller

41: CPU 42: ROM

43: EEPROM 44: RAM

49: D / A Converter 50: Solenoid Driver

60: solenoid 61: moving part

64: coil 65: magnetic member

66: fixed disk 68: movable pin

69: base member 70: nut

90 buttonhole seam
91: buttonhole

92,92: Zigzag portion on left and right sides

93, 93: up and down the basting part 100: sewing machine

M: Fabric Material W: Specific Stroke Section

The present invention relates to a thread tension apparatus of a thread for a sewing machine that can change the tension of the thread by electrical control.

BACKGROUND OF THE INVENTION A tensioning device for a sewing machine thread having a tensioner (such as a thread tension disk type or a rotational tension type) of a thread and a driving means acting on the thread tensioner is already known in the art.

As the driving means, for example, a voice coil motor, a proportional solenoid, or a combination of an air piston and a proportional solenoid valve has been used. By electrically controlling such drive means, for example, the tension applied to the yarn is continuously changed by changing the pressing force between the thread tension disks or by changing the load of the rotation disk of the rotary tensioner.

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However, the conventional driving means described above has the following problems.
First, in the voice coil motor, a coil is wound around the movable portion (plunger), and the lead wire for supplying current to the coil moves in accordance with the movement of the movable portion.
In addition, the voice coil motor has the advantage of having good linearity and responsiveness, but has the disadvantage of requiring an expensive magnet having a strong magnetic force. In addition, the magnet must be enlarged in order to obtain a strong tension in the tensioner of the yarn, thereby raising the cost of the tensioning device.
In addition, the proportional solenoid or the proportional solenoid valve has a characteristic that the thrust is changed as the stroke of the movable part changes even if the electric quantity (current or voltage) is constant. For this reason, when using a disk type tensioner, since the change of stroke and thrust affects the tension of a thread, it is difficult to control the tension of a thread correctly.
The present invention has been proposed to solve the above problems, and an object of the present invention is to provide a tension device for a thread capable of accurately controlling the tension of the thread at a low manufacturing cost.

In order to achieve the above object, the tensioning device of a thread for a sewing machine according to the present invention includes a tensioner mounted on the sewing machine, and a solenoid that acts on the tensioner to change the tension applied to the thread from the tensioner. In the first aspect of the present invention, the solenoid is such that the change in the thrust F of the movable portion of the drive means becomes substantially zero with respect to the change in the stroke S of the movable portion with a constant amount of electricity C supplied to the drive means. It is characterized by. The tension of the thread can be changed by controlling the electric quantity C, and the stroke of the movable part acting on the tensioner is set to a specific stroke section.

According to the first aspect of the present invention, since the stroke is limited to a specific stroke section so that the thrust is not affected by the change of the stroke, the tension of the thread can be controlled accurately and easily. That is, even if the interval between the thread tension disks varies depending on the size of the thread (count of threads), or the thread is slightly deformed due to the pressing force from the tension disks, the thrust of the driving means is increased. The tension of the thread is constantly controlled because it is independent of the stroke change.

Moreover, since the coil is wound on a stationary portion rather than the movable portion, the lead wire of the coil is prevented from being disconnected, thereby improving durability.

In addition, the solenoid can obtain a remarkably large thrust without using an expensive magnet, thereby obtaining a high thread tension at low cost.

According to the second aspect of the present invention, the solenoid is characterized in that the change in thrust F is increased as the amount of electricity C increases under a constant stroke S. Therefore, in the stroke set to a specific stroke section, the tension of the thread increases as the amount of electricity increases.

In the tension device of the thread, it is generally desirable to finely adjust the tension of the thread in a narrow range in the region where the tension of the thread is small, and to adjust the tension of the thread in a relatively wide range in the region of the thread tension. Do. This control is achieved by using the solenoid properties described above.

That is, with respect to the constant amount of electricity change DELTA C, the amount of change in thrust with respect to the amount of electricity change DELTA F is large when the amount of electricity C is large and small when the amount of electricity is small. In addition, the change amount of electricity ΔC can generally be controlled irrespective of the amount of electricity C. Therefore, the tension of the thread can be finely adjusted when the tension is small, and can be adjusted in a wide range when the tension is large.

According to a third aspect of the present invention, a sewing machine is a buttonhole sewing machine for sewing a buttonhole consisting of zigzag portions on the left and right sides and bar-tacking portions on the upper and lower sides by electrical control, and the zigzag portions on the left and right sides. Is sewn at a larger setting range of electricity quantity supplied to the drive means, and the upper and lower tacking portions are sewn at a smaller setting range of electricity quantity.

According to the fourth aspect of the present invention, the left and right zig-zag portions and the upper and lower tempering portions are each sewn at different electric amounts as in the third aspect.

In buttonhole sewing, the needle thread tension is generally set low in the up-and-down basting portions, and high in the zigzag portions on the left and right sides. Depending on the size and shape of the buttonhole seam, the tension of the thread requires fine adjustment in the up and down tacking portions, and the wide range of adjustment in the zigzag portions on the left and right sides.

As in the first and second aspects of the present invention, according to the third and fourth aspects of the present invention, fine adjustment is easily achieved with low tension in the upper and lower tacking portions, and the zigzag portions on the left and right sides are easily achieved. In a very large tension, a wide range of adjustments are easily achieved.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in Fig. 1, the tensioning device 1 of the thread is installed in the arm 81 of the sewing machine 100, so as to look at the upper thread source side when viewed from the take-up 82. Apply tension to the upper thread. The sewing machine 100 of this embodiment is, for example, an industrial circular sewing machine (button hole sewing machine) for forming buttonhole seams 90 as shown in FIG. 9 in the fabric material M provided on the sewing table 83. The buttonhole seam 90 is composed of the left and right zigzag portions 92 and 92 provided on the left and right sides of the button hole 91 and the up and down tempering portions 93 and 93. The sewing machine 100 is sandwiched between the slide plate 85 and the work clamp 86 in the Y direction (FIG. 1), and the needle vibration mechanism provided in the arm portion 81 at the same time. The buttonhole seam 90 is formed by moving the needle 84 in the X direction (FIG. 1) by a needle swing mechanism (not shown). In addition, the work cutter 87 is dropped during the sewing to cut the button hole 91, and when the sewing is completed, the upper thread is cut and held by the thread cutting scissors 88.

On the other hand, when the sewing machine 100 is an eyelet buttonhole sewing machine that forms eyelet buttonhole seams, the eyelet portion corresponds to the above-described basting portion.

When the buttonhole seam 90 is formed, the tension of the upper thread needs to be changed in accordance with the zigzag portions 92 and 92 and the tacking portions 93 and 93 on the left and right sides. That is, since the stitch pitch in the basting portion 93 is relatively large, it is necessary to weaken the tension of the upper thread, whereas the sewing pitch in the zigzag portion 92 on the left and right sides is relatively small, so that the tension of the upper thread is relatively small. You need to be strong. Therefore, the tension of the thread is automatically changed to an appropriate value according to the buttonhole seam 90 by electrically controlling the tensioning device 1 of the thread.

In addition, when the size and shape of the seam 90 as well as the type of fabric material and the feel of the finished seam are changed, the tension in the upper and lower tingling portions and the left and right zigzag portions must be readjusted.

The tensioning device 1 of the thread includes an electronic circuit such as a mechanical part shown in FIGS. 2 and 3, a controller 40 (FIG. 7) for the sewing machine 100, and a solenoid 60, and a solenoid driver ( 50) (FIG. 8).

The thread tensioner 19 shown in Figs. 2 and 3 imparts resistance to the upper thread sandwiched between the fixed disk 66 and the movable disk 67, and the above-mentioned during sewing by the thrust generated by the solenoid 60. The tension of the thread can be changed dynamically so that the resistive force changes continuously.

The screws 71 and 71 pass through the insertion holes 69a and 69a of the base member 69 and the insertion holes 81Aa and 81Aa of the arm part frame 81A. 60a; threaded to threaded bore. By doing so, the base member 69 is fixed to the outside of the arm part frame 81A, and the solenoid 60 is fixed to the inside of the arm part frame 81A.

The movable pin 68 has a slotted head 68c having a threaded portion 68b, a shaft portion 68a, and a slot for a screw driver. The shaft portion 68a has a groove 68d through which the upper thread can pass. The screw portion 68b penetrates through the central through holes 66a and 67a penetrating the fixed disk 66 and the movable disk 67, and the insertion hole 69b penetrating the base member 69, respectively. ) Is screwed into the screw hole 61a formed in the axial direction at the end of the plunger 61. The plunger 61 coincides with the movable portion. The length of the screw engagement (fixed position) between the movable pin 68 and the plunger 61 is adjusted by axially positioning the nut 70 on the threaded portion 68b. Opposite portions between the disks 66 and 67 are disposed in the grooves 68d on the shaft portion 68a. In such a configuration, when the movable disk 67 is moved away from the fixed disk 66 in the axial direction, the head 68c subject to the disk motion moves the plunger 61 in the same direction.

As shown in FIG. 4, the solenoid 60 includes a frame 62, a coil bobbin 63, a coil 64, a plunger 61, and a magnetic member 65. The plunger 61 is supported on the frame 62 by bearings 62A and 62B so as to be movable in the axial direction but not rotated. The magnetic member 65 is fixed at the center thereof integrally with the plunger 61. The magnetic member 65 has a cylindrical shape, and a recessed portion 65a is formed in a portion thereof.

The recess 65a makes the magnetic path permeability constant in the particular stroke section, and the thrust versus stroke characteristics of the solenoid 61 exhibits a hysteresis curve as shown in FIG. That is, there is a specific stroke section (a predetermined range from S in FIG. 5) in which the thrust (indicated by arrow F in FIG. 2) becomes substantially constant when the stroke of the solenoid 61 is changed.

The engagement length of the plunger 61 and the threaded portion 68b changes the plunger position in the axial direction. While the space between the disks 66 and 67 changes from the threadless contact state to the separated state as the upper thread passes between them, the nut 70 is held in a position such that the stroke is in the specific section W. As shown in FIG.

 The process for setting the plunger stroke to the specific section W is as follows. First, the nut 70 is loosened. By rotating the pin 68 with a screwdriver or the like while the disks 66 and 67 are in contact with the base member 69, the plunger from the bottom of the solenoid 60 so that the stroke is in a specific section W. The protrusion amount W 'of the upper end 61b of the protrusion protrudes. The nut 70 is then secured to secure the pin 68 to the plunger 61.

FIG. 6 shows the thrust versus coil current characteristics represented by a hysteresis curve under a constant stroke. This plot shows the characteristic that the amount of change in thrust F increases as the coil current C increases under a certain stroke. The solenoid 60 is arranged to attract the movable pin 68 when the coil 64 is energized. At this time, as the coil current increases, the attracting thrust induced in the movable pin 68 increases.

On the other hand, the sewing data for the buttonhole seam includes not only sewing data including parameters for forming the left and right zigzag portions and the upper and lower tacking portions, but also the tension data of the yarns respectively applied to the left and right zigzag portions and the upper and lower tacking portions. Such thread tension data can be varied in a predetermined range with respect to the standard value input through the operation panel 21 while having each standard value. The solenoid 60 is energized by a current according to specific thread tension data. As described above, the data can be changed in a predetermined range, and the coil current can be changed in a predetermined range as well as the change of this data.

In Fig. 6, the solenoid current with respect to the thread tension of the up-and-down basting portion is set to the range X1, and the solenoid current with respect to the thread tension of the zigzag portions on the left and right sides is set to the range X2, respectively. In this way, a small thrust or a small tension is applied when sewing the up-and-down basting part, and a large thrust or a large tension is applied when sewing the zigzag portions on the left and right sides.

When the tension data changes, the coil current also changes within the range X1 or range X2 in accordance with the data change. When the coil current changes from the range X1 and the range X2 to the minimum amount of change in quantity ΔC, the thrust change over ΔC is greater in the range X2 than in the range X1, which is easy in FIG. Can be observed. Accordingly, the thread tension when sewing the upper and lower hour handed portions corresponding to the range X1 can be finely adjusted, while the thread tension when sewing the zigzag portions on the left and right sides corresponding to the range X2 is relatively wide. I can adjust it.

7 and 8, the controller 40 for the sewing machine 100 includes control means for the tensioning device 1 of the thread. The controller 40 includes a CPU 41, a ROM (Read Only Memory) 42 for storing the control program and the control data, and an EEPROM (Electrically Erasable and Programmable) for storing the sewing data input through the operation panel 21. ROM; 43, a RAM (Random Access Memory) 44 serving as a work area of the CPU 41, a pulse motor control circuit 47 and a clock generator 45 for controlling a pulse motor for cloth transfer and a pulse motor for needle vibration. ), A reset circuit 46, a D / A converter 49 for converting the tension control signal from the CPU 41 into an analog signal, and a solenoid for driving the solenoid 60 connected to the converter 49. The driver 50 (FIG. 8) is provided.

In addition, the CPU 41 includes an operation panel 21 for inputting sewing data and the like through an I / O interface (not shown), a pedal sensor 22 of a sewing machine pedal, a cloth motor pulse motor, and a needle vibration pulse motor. It is connected to the servo detector 23 which detects the drive amount of this, and the mechanical head sensor 24 which detects the position of the needle bar or the work cutter 87. FIG.

The solenoid driver 50 is based on an operational amplifier (OP1) for stabilizing the analog tension control signal from the D / A converter 49 by a negative feedback circuit, and a predetermined magnification of the tension control signal, And a constant current circuit (composed of amplifier OP2, FET Q1, and resistors R1, R2, Rs) for outputting a constant current Iout proportional to the tension control signal to the solenoid 60.

The operation of the sewing machine 100 and the tension device 1 of the thread will be described below. First, sewing data for buttonhole seams such as seam parameters, tension data, and the like are input through the operation panel 21. Concurrently, US patent application Ser. No. 09 / 105,475 discloses an item of setting parameters for buttonhole sewing. Such setting data can be stored in advance in the EEPROM 43, and this data is read at the next setting.

After data setting, the fabric material M is placed on the sewing table 83, and the start pedal is turned on by operating the sewing pedal. When the start switch is turned on, the sewing motor, the cloth transfer pulse motor, and the needle vibration pulse motor are driven to sew the left and right zigzag portions and the upper and lower tacking portions based on the read sewing data. While sewing each part, a tension control signal is output from the CPU 42, so that current is supplied to the solenoid 60 in accordance with the tension control signal through the D / A converter 49 and the solenoid driver 50. FIG.

When a current is supplied to the solenoid 60 in accordance with the tension control signal, thrust (F in FIG. 2) occurs in the plunger 61 with respect to the supplied current value. This thrust is transmitted directly to the movable pin 68 so as to move to the left in FIG. 2, whereby the pair of disks 66, 67 are pressed against each other, imparting resistance (tension) to the upper thread passing between these disks. do.

The tension control signal value is different for the rods in the zigzag portions on the left and right sides and the rods in the upper and lower tempering portions based on the set data. This change in tension control signal changes the thrust of the solenoid, i.e., the pressing force between the disks 66 and 67, further changing the tension of the thread. For example, the current in the range X2 defined by the sewing tension data of the left and right zigzag portions changes the tension to a very high level, and the current in the range X1 defined by the sewing tension data of the tacking portion lowers the tension. Change to level

At this time, the stroke of the plunger 61 or the movable pin 68 is limited to a specific stroke section (W). This makes the thrust constant, whereby the tension does not change even if the disk 67 moves in the axial direction due to deformation of the thread or the like.

On the other hand, since the characteristics of the thrust F versus the coil current C of the solenoid 60 exhibit a hysteresis curve as shown in Fig. 6, the tension control signal to correct the thrust F according to the increase or decrease of the desired tension. It is desirable to calibrate to obtain a more accurate tension.

According to the above-described embodiment of the tensioning device 1, since the stroke of the plunger 61 is set to a specific stroke section W which does not affect the thrust, it is easily carried out regardless of the change of the plunger stroke. Tension can be controlled accurately and consistently. Moreover, the tensioning device 1 is improved in durability and inexpensive as compared with a conventional voice-coil motor type device.

The thrust of the solenoid is increased by the power of the power supply current, and the tension is increased as the thrust of the solenoid increases. This characteristic facilitates the control of the tension of the yarn because it is easy to finely adjust the tension when the tension is small and it is easy to adjust the tension in a relatively wide range when the tension is high. Furthermore, in sewing the buttonhole seam 90, the tension can be finely adjusted when sewing the upper and lower tingling parts 93 and 93, and when sewing the zigzag portions 92 and 92 on the left and right sides, the tension is wide. It is effective because it can be easily adjusted.

The tensioning device 1 of the thread according to the invention can be applied not only to the buttonhole sewing machine described in the embodiment, but also to, for example, a lockstitch sewing machine or other industrial rotary sewing machine. As to the tensioner, the present invention can apply various types of tensioner such as rotational tension in addition to the disk shape as in the embodiment. In addition, for the drive means, instead of transmitting solenoid thrust directly to the tensioning device, thrust may be transmitted to the tensioning device via a connecting member or a transmission member.

According to the invention described in claim 1, since the stroke of the movable portion is set to a specific stroke section which does not affect the thrust, it is possible to easily and accurately control the tension of the yarn regardless of the change of the stroke of the movable portion. Can be. Moreover, the durability is improved and the cost is low compared to the tension device of the conventional voice coil motor type.

According to the invention according to claim 2, it is generally preferable to control the tension of the yarn because it is easy to finely adjust the tension when the tension is small and it is easy to adjust the tension in a relatively wide range when the tension is large. Do.

According to the invention as claimed in claim 3, it is effective to form a seam of a buttonhole which can finely adjust the tension when sewing the upper and lower tacking portions and when sewing the zigzag portions on the left and right sides to adjust the tension in a wide range. .

Claims (4)

A thread tension device 19 of the thread mounted on the sewing machine 100; And As a tensioning device (1) of a thread for a sewing machine including a solenoid (60) which acts on the tensioner and changes the tension applied to the thread by the tensioner, The solenoid has a change in the thrust F of the movable portion 61 of the driving means at least in a specific stroke section W of the stroke S while a constant amount of electricity C is supplied to the driving means. Has a characteristic of being substantially zero with respect to the change of the stroke S, The tension of the thread can be changed by controlling the electricity amount C, The stroke of the movable part acting on the tensioner is a tensioning device of a thread for a sewing machine is set to the specific stroke section. The method of claim 1, wherein the solenoid has a characteristic that the amount of change of the thrust (F) is increased as the amount of electricity (C) increases under a certain stroke (S), The tensioning device of a thread for a sewing machine, characterized in that the tension of the thread is increased as the amount of electricity is increased in the stroke set to the specific stroke section. The button of claim 1, wherein the sewing machine (100) sews button holes (90) formed by zigzag portions (92,92) on the left and right sides and bar-tacking portions (93,93) on the upper and lower sides by electric control. Buttonhole sewing machine, The zigzag portions on the left and right sides are sewn at a larger amount of electricity provided to the driving means, and the upper and lower tacking portions are sewn at a smaller amount of electricity. According to claim 2, The sewing machine 100 is a buttonhole sewing machine consisting of a zigzag portion of the left and right and the top and bottom of the basting part, The zigzag portions on the left and right sides are sewn at a larger amount of electricity provided to the driving means, and the upper and lower tacking portions are sewn at a smaller amount of electricity.

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