JPH02255176A - Adjusting device for thread tension of sawing machine - Google Patents

Abstract

PURPOSE:To bring only a specific tension unit to manual adjustment without losing the balance of each tension unit by providing a conversion axis for displacing simultaneously each conversion cam for converting the pressure force of a pair of tension discs, and a tension dial for displacing independently each tension adjusting body in the axial direction. CONSTITUTION:When a tension dial 3 is turned, a tension control gear 5 turns through an intermediate gear 4 by a gear part 3' formed integrally, but since the tension control gear 5 is screwed on a fixed tension axis 8, it moves in the axial direction, and by expansion and contraction of a tension spring 6, inserting and holding pressure of tension discs 7a, 7b is varied. Also, on a part of an operating piece 17 rotated simultaneously by a rotation of a conversion axis 9 operated by a conversion control 18, a projection 17' is provided, therefore, a conversion cam 10 moves in the axial direction, the tension disc 7b of the opposite side of the tension spring 6 is moved and the inserting and holding pressure of the tension discs 7a, 7b is converted. Accordingly, in a state that the tension of plural tension units remains switched simultaneously by the conversion control, each tension unit can be brought to manual adjustment by a manual tension dial.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thread tension adjustment device for a sewing machine, and more particularly to a thread tension adjustment device for a sewing machine that can adjust the thread tension depending on the type of sewing thread.

[Conventional technology]

Generally, in sewing machines that use multiple threads, such as overlock sewing machines, a thread tension unit is installed for each thread, and the tension of the multiple threads is adjusted for each type of stitch according to the usage conditions such as the fabric and thread used. A method has been adopted to do so.

In other words, it is necessary to adjust the strength of each thread tension unit depending on the type of thread used, such as spun thread, cotton thread, filament thread, etc. Especially in the case of filament thread, it is difficult to set the appropriate thread tension unless you are an expert in sewing. .

Also, in the case of a lock sewing machine, if the needle thread and the upper and lower looper threads are not balanced, it will not be possible to sew the desired edges or warp.
This is extremely inconvenient as trial sewing must be performed many times each time the thread is replaced.

Conventionally, this type of device has been used, for example, in Japanese Patent Application Laid-Open No. 63-257.
As shown in Japanese Patent Application No. 592, a plurality of thread tension units each having a pair of thread tension discs that sandwich a thread and a pressure means that pressurizes the thread tension discs, and at least two thread tension units' pressurizing means. a first thread tension setting means for interlocking the thread tension units to set the thread tension of these thread tension units in one operation; and a first thread tension setting means for operating the pressurizing means of at least two thread tension units independently of each other to set the thread tension of these thread tension units in one operation. A sewing machine comprising a second thread tension setting means for arbitrarily setting the thread tension of the unit, and a switching means for selectively connecting each of the thread tension setting means to the pressure means while maintaining its operating state. There is a thread tension adjustment device.

In such a conventional sewing machine thread tension adjustment device, a pressure member that adjusts the strength of the thread tension spring is provided with a protrusion, and this protrusion is connected to a cam of a set height depending on the type of thread, etc. The thread tension is changed by pushing with a protrusion, and when changing the thread tension, the thread tension of each thread tension unit is changed simultaneously using an interlocking dial.

[Problem to be solved by the invention]

However, in the thread tension adjustment device of the sewing machine described above, if the optimum thread tension cannot be obtained with the cam protrusion of a predetermined height, the interlocking dial is rotated to a specific CH position, and the pressure member This is done by making the cam screw face one of the protrusions, and adjusting the height of this cam screw using a manual dial.In this state, the thread tension setting by the cam protrusion is canceled. For example, when each thread tension unit is switched for filament yarn using an interlocking dial, it is not possible to manually adjust, for example, only one thread tension unit without disturbing the balance of each thread tension unit.

In addition, it is normal for the tension settings to vary depending on the thread path finish, etc.
Standard settings cannot be adjusted. The present invention seeks to eliminate the above-mentioned drawbacks.

[Means to solve the problem]

The thread tension adjustment device for a sewing machine according to the present invention includes a pair of thread tension discs that clamp the thread, a pressure means that pressurizes the thread tension discs, and a conversion cam that is displaced in the axial direction to convert the pressing force of the pressure means. and a thread tension adjustment body, a conversion shaft for simultaneously displacing each of the conversion cams in the axial direction, and a conversion shaft for displacing each of the above-mentioned thread tension adjustment bodies in the axial direction independently of the others; It is characterized by a thread tension dial.

[For production]

In the thread tension adjustment device for a sewing machine of the present invention, each thread tension unit can be manually adjusted using a manual thread tension dial while the thread tensions of a plurality of thread tension units are simultaneously switched using the conversion knob.

〔Example〕

The present invention will be explained in detail below with reference to the drawings.

Figure 1 shows a wooden nail 3 equipped with a thread tension adjustment device according to the present invention.
This shows a regular thread lock sewing machine, and on the front of the main body 1, there are
Thread tension units 2A and 2B adjust the tension of needle thread A, upper louver thread B, and lower looper thread C.

2C is incorporated, and by operating the thread tension dial 3, the thread tension of each thread tension unit can be arbitrarily set independently.

As shown in FIG. 2, each thread tension unit has the same mechanical structure, and one thread tension unit will be explained below.

When the thread tension dial 3 is turned, the thread tension adjusting body (hereinafter referred to as thread tension adjusting gear 5) is rotated by the integrally molded gear part 3'' via the intermediate gear 4. is screwed onto a fixed thread tension shaft 8, so that it moves in the axial direction, and as the thread tension spring 6 expands and contracts, the clamping force of the thread tension discs 7a and 7b is changed. The thread tension shaft 8 is supported by a conversion shaft 9 passing through it.

The receiver supports the thread tension disc 7b on the opposite side of the thread tension spring 6, and the conversion cam 10, which moves in the axial direction according to the unevenness of the cam surface by rotation of the actuating piece 17 fixed to the conversion shaft 9, controls the thread tension. The axially outward movement position is regulated by a stopper 1) fitted on the shaft 8.

In addition to the thread tension shaft 8, the base 12 includes fixed shafts 13 and 14 that support the thread tension dial 3 and intermediate gear 4, and a thread tension disc 7.
A, 7b and a guide pin 15 for preventing rotation of the conversion cam IO are fixed respectively.

Note that 16 is a dial spring, and 18 is a conversion knob fixed to the conversion shaft 9. This dial spring 16 is the standard of the scale 3b (with numbers 1 to 9) engraved on the outer periphery of each thread tension dial 3 when each thread tension unit is set to an appropriate thread tension using the thread tension dial 3. Scale (e.g. (5))
This is to adjust the thread tension to the pointer 3a so that you can easily adjust the strength of the thread tension. After disengaging gear part 3', then turning the thread tension dial 3 and aligning the standard scale provided on its outer periphery with the fixed pointer 3a, meshing gear part 3' and intermediate gear 4. The thread tension dial 3 is returned to a predetermined position by the restoring force of the dial spring 16, so that the strength adjustment can be visually checked. At this time, even if the intermediate gear 4 and the gear part 3' are set to be disengaged, the tension of the thread tension plate will not change.

In addition, in the past, it was necessary to convert each thread tension dial scale as shown in the table below depending on the type of thread, but in the present invention, this conversion operation can be performed by selectively converting one conversion knob so that each conversion cam can be adjusted in the axial direction. By moving the appropriate amount and converting the clamping force of the thread tension plate, each thread tension unit is simultaneously set to an appropriate thread tension value corresponding to the thread used.

A projection 1 is provided on a part of the operating piece 17 that is simultaneously rotated by the rotation of the conversion shaft 9 operated by the conversion knob 18.
7'' is provided, whereby the conversion cam 10 moves in the axial direction, and the thread tension plate 7b on the opposite side of the thread tension spring 6 is moved in the axial direction, thereby converting the clamping force of the thread tension plates 7a and 7b. be done.

That is, as shown in FIG. 3, the conversion cams 10 include a needle thread tension conversion cam 10A, an upper looper thread tension conversion cam 10B, and a lower louver thread tension conversion cam 10C.
A cam lift is formed at 10° on the sliding surface to adjust the thread tension to a predetermined appropriate thread tension depending on the type of thread. Therefore, by converting the conversion knob 18 to a predetermined display position depending on the type of thread used, each actuating piece 17 rotates simultaneously, and each conversion cam 10A, IOB, 40C is moved in the axial direction to the opposite side of the thread tension spring 6. The clamping force is converted by pressing the thread tension plate 7b on the side.

In addition, on the outer periphery of the conversion knob 18, conversion positions for various yarns (not shown) are indicated, for example, (S) for spun yarn, (F) for filament yarn, and (M) for cotton yarn, and positioning recesses are provided at the corresponding positions. is formed, and the pressing spring is crimped onto this.

In another embodiment of the present invention, as shown in FIG. A converting member 19 having a gear-shaped outer periphery is fixed to the converting shaft 9a, the gear of the converting member 19 is meshed with the outer periphery of the actuating piece 17a, and the converting knob 18 is turned. , the conversion member 19, and the actuation piece 17a to adjust each thread tension unit 2^ to 2C.

The conversion shafts 9, 9a in each of the above embodiments may be operated manually, or alternatively, a reversible pulse motor using a select switch or the like may be used.

〔Effect of the invention〕

Since the thread tension adjustment device of the sewing machine of the present invention has the above-mentioned configuration, each thread tension dial is set to an appropriate thread tension using standard thread (for example, spun #80 thread) at the time of shipment, and the thread tension adjustment device is set to an appropriate thread tension by a conversion operation. If the appropriate thread tension is set in accordance with the thread tension, there is no need to operate each thread tension dial each time the thread is replaced, as is the case in the past. Therefore, even beginners can easily sew edges with a good finish without having to make trial stitches many times. In addition, it is easy to make fine adjustments according to the thickness of the fabric and thread, and since there is no need to rotate the thread tension dial to adjust the balance of thread tension, there are no sewing problems and no skill is required. . Further, there is a great advantage that each thread tension unit can be converted and set to a predetermined thread tension while maintaining the tension balance of each thread tension unit depending on the type of thread.

Furthermore, the standard scale (5) of the thread tension dial can be easily set without removing the knob, and assembly adjustment is easy.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a lock sewing machine equipped with a thread tension adjustment device of the present invention, and FIG. 2 is a sectional view of a thread tension unit.
FIG. 3 is an explanatory diagram of a conversion cam, and FIG. 4 is a sectional view of a thread tension unit in another embodiment of the present invention. 1...Main body, 2A, 2B, 2C...Thread tension unit, 3...Thread tension dial, 3"...Gear part,
3a... Pointer, 3b... Scale, 4... Intermediate gear, 5... Thread tension adjustment gear, 6... Thread tension spring,
? a, 7b...Thread tension disc, 8...Thread tension shaft, 9,
9a... Conversion shaft, 10... Conversion cam, 10... Cam sliding surface, 10^... Needle thread thread tension conversion cam, IO
B... Conversion cam for upper looper thread tension, IOC.
・・Conversion cam for lower looper thread tension, 1)・・・Retaining ring, 12・・・Base, 13.14・・・Standard shaft, 15・・
・Guide bin, 16...Dial spring, 17.17a
...Operating piece, 17゛ ...Protrusion, 18...
Conversion knob, 19...Conversion member, A...Needle thread, B.
... Upper looper thread, C... Lower looper thread. Kaji lope bride

Claims (3)

[Claims] (1) A pair of thread tension discs that sandwich the thread, a pressure means that pressurizes the thread tension discs, a conversion cam that is displaced in the axial direction to convert the pressing force of this pressure means, and a thread tension adjustment body. It consists of a plurality of thread tension units, respectively, a conversion shaft for simultaneously displacing each of the conversion cams in the axial direction, and a thread tension dial for displacing each of the thread tension adjustment bodies in the axial direction independently of the others. A thread tension adjustment device for a sewing machine, which is characterized by: (2) The conversion cam is in contact with one of the pair of thread tension discs, the thread tension adjusting body is disposed on the other side of the pair of thread tension discs, and the pressing means is in contact with one of the pair of thread tension discs. A spring is inserted between the other of the thread tension discs and the thread tension adjustment body, and the thread tension adjustment body moves in a direction toward and away from the other of the pair of thread tension discs by rotating the thread tension dial. The thread tension adjustment device for a sewing machine according to claim 1. (3) The thread tension adjustment body is a gear having a threaded portion on the inner circumference and external teeth on the outer circumference, and the threaded portion is screwed to a fixed shaft threaded portion, and the thread tension dial is rotated by the fixed shaft. It is a gear that is supported so as to be freely movable in the axial direction so as to be detached from the thread tension adjustment body, and meshes with the external teeth of the thread tension adjustment body, and has a standard scale on its outer periphery, and has a standard scale on its outer periphery. A return dial spring is connected between the fixed shafts, and the thread tension is adjusted so that when the thread tension dial is removed from the thread tension adjuster, an arbitrary one of the standard scales matches the fixed pointer. 3. The thread tension adjusting device for a sewing machine according to claim 2, wherein the tension dial is adapted to engage with external teeth of the thread tension adjusting body after being rotated against the return dial spring.