JP2003038880A - Tension device of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tension device of a sewing machine which makes it possible to operate a plurality of tension devices by one adjusting device, and also makes it possible to separately adjust each tension device. SOLUTION: The tension device 100 of the sewing machine comprises a tension discs (11a and 11b) for sandwiching a thread, tension springs (15a and 15b) for pressing the tension discs, tension gears (16a and 16b) for engaging one end of each tension spring, and a plurality of tension knobs (30a and 30b) for separately changing a position of each tension gear. The tension gears are interlocked. A second tension knob 50 is provided so that one of the tension gears moves toward a direction to increase tension, and the other tension gear moves toward a direction to decrease tension. Each tension knob can also be operated separately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread tension device for adjusting the tension of upper looper thread and lower looper thread.

[0002]

2. Description of the Related Art A conventional household overlock sewing machine is provided with a plurality of thread tension devices, and the tension can be set by operating a dial on a front panel of the sewing machine. For example, in a thread tension device for an overlock sewing machine for a single needle and three threads, the tensions of the needle thread, the upper looper thread and the lower looper thread are individually set to adjust the thread supply amount.

[0003]

However, the thread tension device in the overlock sewing machine is preset at the time of factory shipment so that the tension of each thread will be the tension balance of general overedging or matching sewing. For this reason, for example, when performing a sewn-up sewing while winding the edge of a handkerchief or the like, it is necessary to individually change the thread tensions of the lower looper thread and the upper looper thread to search for a point at which they can be balanced. I had to make adjustments and make trial stitches many times before I got a good stitch.

Therefore, for example, Japanese Patent Publication No. 5-16880 proposes that each thread tension device is connected by a belt and is adjusted by one dial. But,
There is a problem that the tension balance of each thread tension device can be adjusted only in either the increasing direction or the decreasing direction, and the tension adjustment cannot be performed so as to increase one and decrease the other.

Further, in the example disclosed in Japanese Patent Application No. 5-153471, a thread tension disc is provided at both ends of a threaded shaft, a mover is provided near the center, and a spring is provided between them. It is provided. Then, by moving the mover left and right through the spring, the tension of one thread tension disc is increased and the tension of the other tension disc is decreased to adjust the tension of the looper thread, and the tension of one is increased. Then, the other is smaller. However, since the tension of the thread tension discs provided on both ends of the shaft is adjusted by only one dial operation, there is a problem that each thread tension disc cannot be individually adjusted.

An object of the present invention is to easily adjust tension in a thread tension device of a sewing machine and also to enable fine setting.

[0007]

In order to solve the above problems, the invention according to claim 1 is, for example, as shown in FIGS. 1 and 2, a plurality of pairs of thread tensioners (12) holding a plurality of threads.
a, 12b) and a spring for pressing the thread tension (thread tension spring 1
5a, 15b), a thread tension gear (16a, 16b) for locking one end side of the spring, and a plurality of thread tension knobs (30a, 30b) for individually changing the position of the thread tension gear. In the thread tension device 100 of the sewing machine, the plurality of thread tension gears are interlocked with each other, one thread tension gear is moved in a direction to increase the tension, and the other thread tension gear is moved in a direction to decrease the tension. It is characterized by comprising a tension adjusting means (second thread tension knob device 50) capable of adjusting the tension.

According to the first aspect of the present invention, since the plurality of thread tension gears can be operated in conjunction with each other by the tension adjusting means, the tension can be easily adjusted. Further, since the thread tension knobs for individually changing the thread tension gears are provided, it is possible to operate the thread tension knobs to make fine settings.

According to a second aspect of the invention, in the thread tension device for a sewing machine according to the first aspect, as shown in, for example, FIGS. 1 and 2, the thread tension device is connected to one of the thread tension knobs. A gear (second intermediate gear 22a) is provided, and the tension adjusting means includes a support shaft (shaft 56) provided in the vicinity of the thread tension knob, and a left and right gear portion slidable in the left and right directions on the support shaft. A sliding member having (left gear portion 51, right gear portion 52) is provided, and one of the left and right gear portions is connected to the thread tension gear via the connecting gear by operating the sliding member. Is characterized by.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Thread tension device 10 of this embodiment
The sewing machine to which 0 is applied is, for example, a household overlock sewing machine that forms overedging stitches, joint stitches, and winding stitches, and it is necessary to change the thread tension depending on the type of sewing and the size of the material. Especially when performing winding sewing,
It is necessary to change the supply amount of the upper looper thread (hereinafter, upper thread) and the lower looper thread (hereinafter, lower thread). Therefore, the thread tension can be appropriately changed by mechanically controlling the thread tension device 100. The thread tension device 100 of the present invention sandwiches an upper thread or a lower thread between a pair of thread tensioners 12a and 12b to give resistance to the thread and adjust the supply amount of the upper and lower looper threads.

[First Embodiment] The first embodiment is shown in FIG.
2 and FIG. 2. Regarding the rotation direction of each gear described below, the direction in which the gear passes from the front side to the upper side when viewed from the front and rotates to the back side is the X direction (normal rotation direction),
On the contrary, the direction of passing from the front side to the bottom side and rotating to the back side is Y
Direction (reverse direction). Thread tension device 100 of the present invention
Is provided on an arm of a sewing machine (not shown), and an upper thread tension device 2 for adjusting the tension of the upper thread and a lower thread tension device 3 for adjusting the tension of the lower thread are provided on the mounting plates 4, 5. They are assembled side by side.

The upper thread tension device 2 is provided on the left side of the mounting plate 4 in front view. The left and right side plates 6 and 7 of the mounting plate 4 are provided with a cylindrical thread tension shaft 11a.
One end of a is fixed to the right side plate 7. The other end of the thread tension shaft 11a has a thread tension 12 which will be described later.
It is inserted into a shaft hole (not shown) provided in a and is fixed to the left side plate 6.

The thread tension shaft 11a has a pair of thread tension members 12
A, a thread tension spring (spring) 15a, a thread tension gear 16a, etc. are fitted. Screws are formed in a predetermined section (for example, the width of a first intermediate gear 20a described later) on the outer periphery of the thread tension shaft 11a. Further, a thread is formed on the inner diameter of the thread tension gear 16a, and the thread is engaged with the thread on the outer circumference of the thread tension shaft 11a.

The thread tension gear 16a is provided with ring-shaped members 16aa and 16ab with the gear portion interposed therebetween. The inner diameter is formed to be slightly larger than the outer diameter of the thread tension shaft 11a, and is attached so as to be slidable in the axial direction of the thread tension shaft 11a.

The thread tension 12a includes a fixed plate 13a and a movable plate 1.
4a, a concave surface is formed from the peripheral edge toward the center, and a circular shaft hole is formed in the center. Then, the fixed plate 13a and the movable plate 14a are arranged such that the surfaces of the movable plate 14a and the surface opposite to the concave surface thereof are brought into contact with each other, and the yarn is held at the contacting portion. A plate retainer (not shown) is provided on the concave surface of the movable plate 14a. Also, for the plate holder,
The end of the thread tension spring 15a is locked, and the disc holder is pressed by the urging force of the thread tension spring 15a.

Further, the thread tension spring 15a includes the thread tension shaft 11a.
It is wound in a coil shape along the axial direction of a, one end of which is fixed to the movable dish 14a, and the other end of which is joined to the thread tension gear 16a, and the thread tension gear 16a moves left and right. As a result, the pressure applied to the movable plate 14a is changed, and the clamping pressure between the thread tensioners 12a is changed.

When the thread tension gear 16a and the thread of the thread tension shaft 11a are engaged with each other, the thread tension gear 16a moves leftward when it rotates in the X direction and is engaged with the thread tension gear 16a. The thread tension spring 15a is biased to the left. Then, pressure is applied to the movable dish 14a via a dish retainer joined to the left end of the thread tension spring 15a, and a resistance force is applied to the thread sandwiched between the thread tensioners 12a. On the contrary, thread tension gear 1
When 6a rotates in the Y direction, it moves to the right, and the thread tension spring 15a joined to the thread tension gear 16a extends to the right against the biasing force. Then, the pressure applied to the movable plate 14a is reduced through the plate retainer joined to the left end portion of the thread tension spring 15a, and the resistance force applied to the yarn is decreased.

A shaft 21a is provided below the thread tension gear 16a.
Is provided, and one end side of the shaft 21a is fixed to the right side plate. A first intermediate gear 20a is rotatably provided on the shaft 21a. Then, the first intermediate gear 20a
Is the thread tension gear 16a and the thread tension knob 30 described later.
It is in a state of meshing with the gear 31a of a. The second intermediate gear (connecting gear 22a) has the same configuration as the first intermediate gear 20a. The second intermediate gear 22a is a thread tension knob 30a.
Of the thread tension knob 30a is engaged with the gear 31a of the thread tension knob 30a. Further, when operating a second thread tension knob device which will be described later, the second thread tension knob device 50 is operated.
It engages with the left gear portion 51.

Next, the thread tension knob 30a will be described. The thread tension knob 30a is provided on the front surface of the panel of the sewing machine (not shown) and can be operated from the outside.
And a gear 31a that meshes with the first intermediate gear 20a and the second intermediate gear 22a. An engagement hole 33a is provided inside the thread tension knob 30a.
A support shaft 34a is attached to the inside of the. The support shaft 34a is provided with a locking spring 35a along the engaging hole 33a.
Is wrapped around. A front end portion of the locking spring 35a on the left side in front view is formed with a locking portion 36a that bends in the vertical direction, and the locking portion 36a is locked to the inner wall of the engaging hole 33a of the thread tension knob 30a. There is. The thread tension knob 30a is formed to be slidable in the left-right direction by the locking spring 35a.

In the thread tension knob 30a, in a normal state, the gear 31a is kept in mesh with the first intermediate gear 20a and the second intermediate gear 22a provided above and below the thread tension knob 30a. Further, the knob portion 32a
Is moved to the left, the locking spring 35a contracts and the thread tension knob 30a slides to the left,
The meshing with the first intermediate gear 20a and the second intermediate gear 22a is released. Further, the thread tension knob 30a is
It is structured such that it is returned to its original position by the urging force of the locking spring 35a and meshes with the first intermediate gear 20a and the second intermediate gear 22a.

Next, the lower thread tension device 3 will be described.
The lower thread tension device 3 has substantially the same configuration as the above-described upper thread tension device 2, and the thread tension shaft 11b, the thread tension 12b, the thread tension spring 15b, the thread tension gear 16b, and the like have the same configurations, and therefore description thereof will be omitted. In the thread tension device 100 of the present invention, the tensions of the upper thread and the lower thread are adjusted so as to increase one of them and weaken the other when performing the winding sewing. Therefore, by operating the second thread tension knob device 50 described later, the thread tension gears 16a and 16b of the respective thread tension devices 2 and 3 are moved in the right and left opposite directions, so that the second thread tension knob device 50 and the thread tension device The number of intermediate gears through the gears 16a and 16b is smaller in the lower thread tension device 3.

The respective thread tension knobs 30a and 30b are configured such that, on the upper thread tension device 2 side, a second intermediate gear 22a is provided below the gear 31a, and a second thread to be described later is provided through the second intermediate gear 22a. The rotation of the left gear portion 51 of the tone control device 50 is transmitted to the gear 31a. On the other hand, on the lower thread tension device 3 side, a second gear 36b is provided at a position where it comes into contact with the right side surface of the thread tension knob 30b, and the right gear portion 52 and the second gear 36b of the second thread tension knob device 50 described later mesh with each other. When the right gear portion 52 rotates, the gear 31a and the second gear
The gear 36b is rotated in synchronization with the gear 36b.

Next, the second thread tension knob device 50 will be described. The second thread tension knob device 50 operates the upper thread tension device 2 and the lower thread tension device 3 at the same time, and rotates the respective thread tension gears 16a and 16b in opposite directions to supply the upper thread and the lower thread. To adjust. The second thread tension knob device 50 is provided below the upper thread tension device 2 and the lower thread tension device 3. Also, holes are provided in the left and right walls 53a and 53b of the substantially U-shaped support member 53, and the shaft 56 is inserted into these holes, and the retaining ring is provided from the outside of the left and right walls 53a and 53b of the support member 53. 57
It is fixed via a and 57b. The shaft 56 is provided with a sliding portion 55 that covers the outer circumference, and the sliding portion 55 is slidable in the axial direction of the shaft 56. Sliding part 5
A knob portion 58 is provided at substantially the center of 5, and the knob portion 58 is exposed on a front panel of a sewing machine (not shown) and can be operated from the outside. By rotating the knob portion 58, the sliding portion 55 is moved. The shaft 56 is rotatable around its circumference.

The left gear portion 5 is provided at the left end of the sliding portion 55.
1, and a right gear portion 52 is arranged at the right end of the sliding portion 55. It can be moved right and left by operating the knob portion 58. A spring 59 is provided at a position between the sliding portion 55 and the left side wall 53a. In a normal state, as shown in FIG. 1, the spring 59 is in an expanded state, and the left gear portion 51 and the right gear portion 52 are integrated with the sliding portion 55 and are located on the right side of the shaft 56. There is.

Next, the operation of the thread tension device 100 of the present invention will be described. A case where the upper and lower thread tension devices 2 and 3 are individually operated in the above configuration will be described. First, the operation of the needle thread tension device 2 will be described. As shown in FIG. 1, when the knob portion 32a of the thread tension knob 30a is rotated in the X direction, the first intermediate gear 20a meshed with the gear 31a of the thread tension knob 30a rotates in the Y direction. Then, the thread tension gear 16a meshing with the first intermediate gear 20a rotates in the X direction. When the thread tension gear 16a rotates in the X direction, the thread tension gear 16a moves leftward along the thread tension shaft 11a. Thread tension gear 16a
When the thread tension spring 15a is pushed leftward, the thread tension 12a is pressed, the clamping pressure between the thread tensions 12a increases, and the supply amount of the upper thread sandwiched by the thread tension 12a decreases.

On the contrary, when the thread tension knob 30a is rotated in the Y direction, the thread tension gear 16a is rotated in the Y direction via the first intermediate gear 20a. Then, the thread tension spring 15a is urged in the right direction, so that the clamping pressure between the thread tensions 12a decreases, and the supply amount of the upper thread sandwiched by the thread tension 12a increases.

The operation of the lower thread tension device 3 is similar to that of the upper thread tension device 2. By rotating the thread tension knob 30b in the X direction, the first intermediate gear 20b rotates in the Y direction and the mover 17b moves to the left. Move in the direction. Then, the thread tension spring 15b engaged with the mover 17b is biased in the left direction, so that the clamping pressure between the thread tensions 12b is increased and the thread tension 1
The supply amount of the lower thread sandwiched between 2b is reduced. On the contrary, when the thread tension knob 30b is turned in the Y direction, the mover 17b moves to the right and the thread tension spring 15b engaged with the mover 17b.
Is urged to the right, the clamping pressure of the thread tensioner 12b decreases, and the supply amount of the lower thread clamped by the thread tensioner 12b increases.

Next, a case where both the upper thread tension device 2 and the lower thread tension device 3 are adjusted simultaneously will be described. In this case, as shown in FIG. 2, the knob portion 58 of the second thread tension knob device 50 is grasped and slid to the left. When the knob portion 58 is moved leftward, the sliding portion 55 moves to the left gear portion 5
1 and the right gear part 52 move integrally to the left.
When the knob portion 58 is slid to the left by a predetermined amount, the left gear portion 51 moves the second intermediate gear 22 of the needle thread tension device 2.
a and the right gear portion 52 are the thread tension knobs 3 of the lower thread tension device 3.
It moves to a position where it can mesh with the second gear 36b of 0b. Then, the left gear portion 51 is engaged with the second intermediate gear 22a on the upper thread tension device 2 side, and the right gear portion 52 is engaged with the second gear 36b on the lower thread tension device 3 side, and the knob of the second thread tension knob device 50 is engaged. The part 58 is rotated in the X direction or the Y direction.

The knob portion 58 of the second thread tension knob device 50
Is rotated in the X direction, on the needle thread tension device 2 side, the second intermediate gear 22a meshed with the left gear portion 51 of the second thread tension knob device 50 rotates in the Y direction, and
Gear 3 of thread tension knob 30a meshed with intermediate gear 22a
1a rotates in the X direction. And thread tension knob 30a
Thread tension gear 16 that meshes with the first intermediate gear 20a by rotating the first intermediate gear 20a that meshes with the first gear 31a
a rotates in the X direction. The rotation of the thread tension gear 16a causes the thread tension spring 15a to move in a direction of pressing the thread tension 12a. Therefore, the clamping pressure applied to the thread tension 12a is increased, the resistance to the upper thread is increased, and the supply amount of the upper thread is reduced.

When the knob portion 58 of the second thread tension knob device 50 is rotated in the X direction, the thread that is meshed with the right gear portion 52 of the second thread tension knob device 50 on the lower thread tension device 3 side. The second gear 36b of the tone knob 30b rotates in the Y direction. Further, the gear 31b rotates in the Y direction in synchronization with the second gear portion 36b. Then, the thread tension gear 16b is inserted through the first intermediate gear 20b meshed with the gear 31b.
Rotates in the Y direction. The rotation of the thread tension gear 16b causes the thread tension spring 15b to move in a direction of decompressing the thread tension 12b. Therefore, the clamping pressure applied to the thread tension 12b is reduced, the resistance to the lower thread is weakened, and the amount of the lower thread supplied is increased.

On the contrary, when the knob portion 58 of the second thread tension knob device 50 is rotated in the Y direction, the operations of the upper thread tension device 2 and the bobbin thread tension device 3 described above become opposite, On the thread tension device 2 side, the holding pressure applied to the thread tension 12a is reduced, the resistance to the upper thread is weakened, and the supply amount of the upper thread is increased. Further, on the lower thread tension device 3 side, the thread tension spring 15b moves in the direction of increasing the clamping pressure. Therefore, the clamping pressure applied to the thread tension 12b increases, the resistance to the lower thread becomes stronger, and the supply amount of the lower thread decreases.

In the second thread tension knob device 50, after the adjustment of the upper and lower thread tension devices 2 and 3 is completed, the grip portion of the knob portion 58 is released so that the sliding portion 55 is separated from the sliding portion 55 and the left side plate. It is automatically returned to its original position by the urging force of the sandwiched spring 59.

Further, the tensions of the upper thread and the lower thread set by the second thread tension knob device 50 may be adjusted during sewing. In that case, the upper thread tension device 2 or the lower thread tension device 3
By operating the thread tension knobs 30a and 30b of
Fine adjustment of the tension of the upper thread and the lower thread can be operated independently.

In the thread tension device 100 of the sewing machine according to the first embodiment, as described above, the thread tension knob 30a of the taper thread tension device 2 and the thread tension knob 3 of the bobbin thread tension device 3 are used.
0b can be rotated in an interlocking manner by operating the knob portion 58 of the second thread tension knob device 50, so that the tension can be easily adjusted.

Further, the second intermediate gear 2 is provided on the needle thread tension device 2 side.
Since 2a and 22b are provided, each thread tension knob 3
Since 0a and 30b rotate in opposite directions, and the tensions of the upper thread and the lower thread can be adjusted so that one is stronger and the other is weaker, it is possible to easily balance the tensions of the upper thread and the lower thread.

Further, the thread tension knob 3 of the upper thread tension device 2
0a and the thread tension knob 30a of the bobbin thread tension device 3 can be individually operated, so that fine setting corresponding to the type of sewing can be performed. The tension adjusting means of the first embodiment is the support shaft 5 provided close to the thread tension knobs 30a and 30b.
6 and the support shaft 56 is slidable in the left-right direction,
And a sliding member 55 having left and right gears. Then, by operating the sliding member 55, the left and right gear portions 5
One of the first and the second gears 52 is connected to the thread tension gears 16a and 16b via a connection gear 22a.

[Second Embodiment] FIG. 3 is a view showing a modification of the thread tension device 100 of the present invention. The thread tension device 100a according to the second embodiment has a structure different from that of the first embodiment, and instead of the second thread tension knob device 50 shown in FIG.
0b is used to adjust the upper thread tension device 2 and the lower thread tension device 3. It should be noted that the reference numerals and the description of the parts having the same components as those of the first embodiment will be omitted.

The stepping motors 60a, 60b are provided above the upper thread tension device 2 and the lower thread tension device 3, and drive shafts 61a, 61b extend from the respective stepping motors 60a, 60b. The drive shafts 61a and 61b are provided with drive gears 62a and 62b, and the drive gears 62a and 62b are positioned so as to mesh with the thread tension gears 16a and 16b. The rotation of the stepping motors 60a and 60b is controlled by a control signal from a control circuit (not shown). The control circuit calculates the rotation amount of each of the stepping motors 60a and 60b from the supply amount of the upper thread or the lower thread due to the difference in sewing based on a control program input in advance, and sends a signal. Then, the thread tension gears 16a and 16b of the upper thread tension device 2 and the lower thread tension device 3 meshed with the respective drive gears 62a and 62b of the stepping motors 60a and 60b rotate, and the thread tension springs 15a and 15b rotate. 12a, 1
2b is moved in a direction of increasing or decreasing pressure. Therefore, the clamping pressure applied to the thread tensioners 12a and 12b increases or decreases, and the resistance to the upper thread or the lower thread is changed to change the supply amount of the upper thread or the lower thread.

At the time of overedging and joint sewing, the tensions of the upper thread and the lower thread are controlled to be the same, and when changing to the winding stitch, one of the tensions is strong and the other tension is weak. Control. As described above, in the thread tension device 100a using the stepping motors 60a and 60b according to the present embodiment, the tension balance between the upper thread and the lower thread is controlled according to the difference in the sewing method, so that no skill is required,
Anyone can easily operate the thread tension device 100a. The tension adjusting means of the second embodiment is composed of thread tension gears 16a, 16a.
It is composed of stepping motors 60a and 60b for driving b and a control program.

In the above embodiment, the present invention is applied to an overlock sewing machine having two sets of thread tension devices 100, but the present invention is not limited to this and is applicable to all sewing machines having one or more thread tension devices 100. it can. Further, the present invention is not limited to the one described in the above embodiment, but various modifications can be made. For example, the position of the second thread tension knob device 50 is not limited to the position shown in FIG. 1 and may be arranged at another position.

[0041]

According to the invention described in claim 1 or 2, since the plurality of thread tension gears can be operated in conjunction with each other by the tension adjusting means, the tension can be easily adjusted.
Further, since the thread tension knobs for individually changing the thread tension gears are provided, it is possible to operate the thread tension knobs to make fine settings.

[0042]

[Brief description of drawings]

FIG. 1 is a front view showing a thread tension device of the present invention.

FIG. 2 is a diagram showing a state in which the second thread tension knob device is engaged with the thread tension gears of the upper thread tension device and the lower thread tension device in the thread tension device of FIG. 1;

FIG. 3 is a diagram showing a modified example of the thread tension device of FIG. 1, in which a stepping motor is used as tension adjusting means.

[Explanation of symbols]

100, 100a Thread tension device 2 Upper thread tension device 3 Lower thread tension device 11a, 11b Thread tension shaft 12a, 12b Thread tension 15a, 15b Thread tension spring (spring) 16a, 16b Thread tension gear 20a, 20b First intermediate gear 22a , 2nd intermediate gear (coupling gear) 30a, 30b Thread tension knob 50 Second thread tension knob device (tension adjusting means) 51 Left gear portion (gear) 52 Right gear portion (gear) 55 Sliding member 56 Shaft (support shaft) ) 60a, 60b Stepping motor

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Claims (2)

[Claims] 1. A plurality of pairs of thread tensioners for holding a plurality of threads,
A thread tension device for a sewing machine, comprising: a spring that presses the thread tension; a thread tension gear that locks one end of the spring; and a plurality of thread tension knobs that individually change the position of the thread tension gear. A tension adjusting device is provided which is capable of interlocking the thread tension gears, moving one of the thread tension gears in a direction of increasing the tension, and moving the other thread tension gear in a direction of decreasing the tension. Characteristic sewing machine thread tension device. 2. The thread tension device for a sewing machine according to claim 1, wherein the thread tension device includes a connecting gear that is connected to one of the thread tension knobs, and the tension adjusting means is adjacent to the thread tension knob. And a sliding member that is slidable in the left-right direction on the supporting shaft and that has a left and right gear portion. One of the left and right gear portions is connected to the connecting gear by operating the sliding member. A thread tension device for a sewing machine, wherein the thread tension device is connected to the thread tension gear via the thread tension gear.