JP2000079289A - Thread presence or absence detector of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to surely detect the presence or absence of a thread with substantially no influence of the slack of the thread and further to easily set the thread to a thread presence or absence detector as the thread presence or absence detector of a sewing machine. SOLUTION: The thread presence or absence detector for detecting the presence or absence of the needle thread A of the sewing machine has a light emitting section 12, a light receiving part 14 for receiving the light from this light emitting part 12 and a thread guide member 10 having slender thread guide grooves 17 and 27 penetrating the top of the optical path connecting the light emitting part 12 and the light receiving part 14 in a direction intersecting across the prescribed length. The needle thread A is passed into these thread guide grooves 17 and 27 and the change in the photodetecting quantity accompanying the presence or absence of the needle thread A in the thread guide grooves 17 and 27 is detected, by which the presence or absence of the needle thread is detected. The thread guide member 10 has apertures 16 and 26 for thread insertion which are bent and are communicated with the thread guide grooves 17 and 27 and open outward.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sewing machine,
The present invention relates to a device for detecting the presence or absence of a sewing thread to be used for sewing.

[0002]

2. Description of the Related Art In a sewing machine, a sewing thread detecting device disclosed in Japanese Patent Application Laid-Open No. H3-1896 is known for detecting the presence or absence of a sewing thread to be used for sewing. This sewing machine thread detecting device includes a light emitting device, first and second plates through which light from the light emitting device passes, and a detecting unit including a light receiving device having a slit disposed on a front surface thereof. Threads are passed between the plates, and the change in the amount of received light accompanying the passage of the threads is detected to detect the presence or absence of the sewing thread. Further, in such a conventional sewing thread detecting device, in order to securely pass the thread through the center of the detecting unit,
Two guide pins are arranged above and below the detection unit, each being offset by an equal amount to the left and right with respect to the center axis of the slit.

[0003]

However, in the conventional sewing thread detecting device as described above, in order to ensure that the thread passes through the center of the detecting unit, as described above, the center axes of the slits are disposed above and below the detecting unit. Since two guide pins, each of which is offset by the same amount to the left and right, are arranged, the yarn must be set along these four guide pins, that is, the yarn is sent to the yarn detecting device. There was a problem that it took time to set. In addition, in order to prevent erroneous detection due to the yarn moving out of the slit due to the slack of the yarn, it may be necessary to limit the detection phase or the like.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a yarn presence / absence detection device which is less susceptible to slack in a sewing machine and can reliably detect the presence / absence of a yarn. Still another object of the present invention is to make it possible to easily set a yarn in the yarn presence / absence detecting device.

[0005]

According to a first aspect of the present invention, there is provided an apparatus for detecting the presence or absence of an upper thread of a sewing machine, comprising: a light emitting section; A light receiving unit for receiving light, and a yarn guiding member having a thin yarn guiding groove penetrating in a direction intersecting over a predetermined length on an optical path connecting the light emitting unit and the light receiving unit; It is characterized in that the upper thread is passed through and a change in the amount of light received according to the presence or absence of the upper thread in the thread guide groove is detected to detect the presence or absence of the upper thread.

Here, a light emitting diode (LED) may be used as the light emitting unit, but another light emitting element may be used. A solar cell may be used as the light receiving unit, but another light receiving element may be used. The thread guide member is desirably a dual-purpose part incorporating a light-emitting part and a light-receiving part. However, it may be a part dedicated to thread guidance, or may be an integral part consisting of two parts consisting of a main body and a cover. May be.

[0007] As described above, according to the first aspect of the present invention, the fine thread guide groove penetrates the optical path connecting the light emitting portion and the light receiving portion of the thread guide member over a predetermined length in a direction intersecting the predetermined length. It is a yarn presence / absence detection device through which a light passes through a light path connecting the light emitting unit and the light receiving unit in a direction intersecting a predetermined length in a thin yarn guide groove. Is detected, for example, even if the upper thread is slackened, the presence of the upper thread can be reliably detected.

According to a second aspect of the present invention, there is provided the sewing machine thread detecting device according to the first aspect, wherein the thread guide member is bent and communicates with the thread guide groove to open outward. A feature having an insertion opening. For example,
The thread insertion opening is continuous with one end of the thread guide groove.

As described above, according to the second aspect of the present invention, the yarn guide member according to the first aspect has a yarn insertion opening that is bent and communicates with the yarn guide groove and opens outward. As a result, the upper thread can be passed through the thread guide groove by merely inserting the upper thread into the thread insertion opening with respect to the thread guide member.

[0010] The third aspect of the present invention is the first or second aspect.
The thread guide groove of the sewing machine according to claim 1, wherein the thread guide groove is disposed at a position offset to one side with respect to a line segment connecting two thread guide portions provided on the sewing machine main body, and the optical path and the offset direction. Is characterized in that the yarn guide member is arranged so as to substantially follow.

Thus, according to the third aspect of the invention, the thread guide groove according to the first or second aspect is offset on one side with respect to a line connecting the two thread guide portions of the sewing machine main body, Since the thread guide member according to claim 1 or 2 is arranged so that the optical path described in claim 1 and the offset direction are substantially along, the upper thread can be stably positioned in the thread guide groove during rotation of the sewing machine. The presence of the upper thread can be reliably detected.

According to a fourth aspect of the present invention, there is provided the sewing machine thread detecting device according to the third aspect, wherein the upper thread is led into the thread guide section and the thread insertion opening on the surface of the sewing machine body. Configuration with a thread hook groove for guiding
For example, the thread hook groove is formed in a sewing machine body cover attached to the sewing machine body.

According to the fourth aspect of the present invention, the upper surface of the sewing machine is guided so that the upper thread is guided to the thread guide portion and the thread insertion opening. Since the thread catch groove is provided, the upper thread can be hooked on the two thread guide portions of the machine body simply by moving the upper thread along the thread catch groove on the surface of the sewing machine. From the thread guide groove.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a thread detecting device for a sewing machine according to the present invention will be described below with reference to FIGS. First, FIG. 1 is a schematic perspective view showing a sewing machine equipped with a yarn presence / absence detecting device as an example to which the present invention is applied. In the drawing, A is an upper thread, 1 is a sewing machine main body, 2 is a sesame thread (thread winding), 3 Is the thread guide section on the thread sesame side, 4 is the thread guide section on the face plate side,
5 is a face plate, 6 is a thread tensioner, 7 is a thread take-up spring, 8 is a balance,
9 is a needle, 10 is a thread guide member, 11 is a thread guide main body, 21 is a thread guide cover, and 31 is a thread hook groove.

As shown in the drawing, in the sewing machine main body 1, the upper thread A unwound from the thread sesame (thread winding) 2 in the sewing machine arm works on the thread sesame side thread guide section 3 and the face plate side thread guide section 4. The sewing machine is hung from the rear side of the sewing machine opposite to the user, is hung on the thread tensioner 6 of the face plate 5 provided with the face-plate-side thread guide 4, and is hung on the thread take-up spring 7 and the balance 8, and the needle 9
Is passed through the eye. A yarn presence / absence detecting device is provided between the yarn sesame-side yarn guide portion 3 and the face plate-side yarn guide portion 4. This yarn presence / absence detection device includes a yarn sesame-side yarn guide portion 3.
The yarn guide member 10 is disposed at an offset position on the rear side with respect to a line segment (yarn path) L connecting between the yarn guide member 4 and the face plate side yarn guide portion 4.

As shown in FIG. 2, the thread guide member 10 has a rectangular parallelepiped thread guide body 11 extending in the front-rear direction, and a sheet metal thread guide cover 2 fitted to the thread guide body 11.
1 and 2 parts. Yarn guide body 1
1, as shown in FIGS. 2 and 3 (a) and (b),
An LED 12 as a light emitting unit is fixed to a storage recess 13 opened on the rear surface side, while a solar cell 14 as a light receiving unit is
Are fixed to a storage recess 15 opening to the front side. The LED 12 and the solar cell 14 are arranged facing each other on the same axis.

Further, a thread insertion opening 16 which is opened on the upper surface and both side surfaces is formed in the thread guide body 11 at an angle, and a rear end portion is connected to a lower end of the thread insertion opening 16. The yarn guide groove 17 is formed horizontally. Specifically, the thread insertion opening 16 has a shape that is inclined forward and downward toward the operator.
The rear portion of the yarn guide body 11 is successively lower than the
It has become. The thread guide groove 17 is formed so as to penetrate the optical path connecting the LED 12 and the solar cell 14 in a direction crossing over a predetermined length direction. That is, the yarn guide groove 17 is formed so as to be horizontal including the same axis line of the LED 12 and the solar cell 14 so that the yarn does not break when the yarn is inserted and the insertion resistance is not so much generated. The width of the guide groove 17 in the front-rear direction extends to the vicinity of the storage recess 13 of the LED 12 and the storage recess 15 of the solar cell 14. At the front and rear ends of the thread guide groove 17, a small hole 13a for transmitting the light of the LED 12 and a small hole 15a for causing the solar cell 14 to capture the light are formed, respectively.

The thread guide cover 21 has left and right side plates 23, 23 which are continuous with the upper plate 22. The upper plate 22 has an upper surface excluding the rear concave step 18 of the yarn guide main body 11. Is fixed with screws. The side plate 23 has a thread insertion opening 26 and a thread guide groove 27 that are the same as or slightly smaller than the thread insertion opening 16 and the thread guide groove 17 of the thread guide body 11.
Is formed, and the rear concave step portion 1 of the yarn guide main body 11 is formed.
A rear concave step 28 that is slightly higher than 8 is formed. The upper plate 22 of the yarn guide cover 21 is attached to the yarn guide main body 1.
The thread guide member 10 is assembled by screwing and fixing to the upper surface portion excluding the rear concave stepped portion 18. In addition, the thread insertion openings 16 and 26 and the thread guide grooves 17 and 28 are set to a size through which a thread having a maximum usable thickness determined by the sewing machine main body 1 passes.

As shown in FIG. 1, the above-described yarn guide member 10 is positioned rearward with respect to a line (yarn path) L connecting the yarn sesame side yarn guide portion 3 and the face plate side yarn guide portion 4. It is mounted on the sewing machine main body 1 with the offset arrangement. That is, the yarn guide member 10
The front ends of the yarn guide grooves 17 and 27 are offset rearward (in the direction in which the yarn is bent) with respect to the line segment (yarn path) L, and are arranged substantially along the direction in which the yarn guide grooves 17 and 27 are offset. I do. As shown in FIG. 1, the surface of the sewing machine body cover attached to the upper part of the sewing machine arm of the sewing machine body 1 is parallel to the line segment (thread path) L on the rear side, and has a sewing machine arm tip. On the (head) side, a thread hooking groove 31 which smoothly curves forward and forms an L-shape in plan view toward the face plate side thread guide 4 is formed. The thread catch groove 31 further extends below the face plate 5 along the front surface of the sewing machine arm head, and then extends upward between the face plate 5 and the thread take-up spring 5 to the vicinity of the balance 8.

Next, the manner of threading will be described. An operator picks up the upper thread A fed from the thread sesame 2 with his / her finger, and puts the upper thread A into a thread hooking groove 3 having an L-shape in plan view on the surface of the cover of the sewing machine main body above the sewing machine arm of the sewing machine main body 1.
1 and along the extension extending below the face plate 5 at the front of the sewing machine arm head, and then to the vicinity of the balance 8 along the extension between the face plate 5 and the thread take-up spring 5. Move. Thereby, the upper thread A is threaded from the thread sesame side thread guide section 3 to the face plate side thread guide section 4 from the rear side, and the thread insertion openings 16,
The thread can be threaded from the rear side to the thread guide grooves 17 and 27 from the rear side, and can also be threaded to the thread tensioner 6, the thread take-up spring 7 and the balance 8. The sewing preparation is completed when the operator passes the upper thread A through the eye of the needle 9.

Thus, when the thread is hooked on the sewing machine, as shown in FIGS. 1, 3A and 3B, the thread guide groove 1 of the thread guide member 10 is used in the thread presence detecting device.
Since the upper thread A is pressed against the front end side of the thread guide grooves 17 and 27 by the tension of the thread, the light of the LED 12 is blocked by the upper thread A. ,
The amount of light reaching the solar cell 14 is reduced. Then, when the yarn wound around the yarn sesame 2 disappears and the yarn end passes through the yarn guide grooves 17 and 27, the amount of light reaching from the LED 12 to the solar cell 14 increases. Such a change in the voltage of the solar cell 14 due to the change in the light amount causes the upper thread A
Can be detected. An example of such a voltage change of the solar cell 14 is shown in FIG.

In the above, the thread presence / absence detection device is connected to a known central control device mounted on the sewing machine. When it is detected that the upper thread A is not present, for example, an error is displayed and sewing is performed. It is configured to prevent defective products.

As described above, the LED 12 and the solar cell 14
The upper thread A passes through the fine thread guide grooves 17 and 27 penetrating in the direction intersecting over the optical path connecting the two in a predetermined length direction, and the presence or absence of the upper thread A blocking the light of the LED 12 in the thread guide grooves 17 and 28 Is detected, it is hard to be affected by the slack of the yarn and the like, and the presence or absence of the yarn can be reliably detected. That is, as shown by a virtual line in FIG.
The presence of the upper thread A can be reliably detected.

The yarn guide grooves 17 of the yarn guide member 10,
Since the yarn insertion openings 16 and 26 are continuous with 27,
Only by inserting the upper thread A into the thread insertion openings 16 and 26, the thread can be easily set in the thread presence / absence detection device through the thread guide grooves 17 and 27.

Further, on the rear side (in the direction in which the yarn is bent) with respect to the line segment L connecting the yarn sesame-side yarn guide portion 3 and the face plate-side yarn guide portion 4.
The thread guide members 10 (the thread guide grooves 17 and 27) are offset and the thread insertion openings 16 and 26 thereof are directed to the thread catch grooves 31 on the surface of the cover of the sewing machine.
By simply moving the upper thread A along the upper thread A, the upper thread A can be passed from the thread insertion openings 16 and 26 to the thread guide grooves 17 and 27, and the thread can be easily set in the thread presence detector. The upper thread A can be stably positioned in the thread guide groove 17.

In the above embodiment, the yarn insertion opening is provided at one end of the yarn guide groove. However, the present invention is not limited to this. It may be a thread insertion opening that is continuous with the thread. In the embodiment, the yarn guide groove is offset from the line connecting the yarn sesame side and the face plate side with the yarn insertion opening facing the rear side. On the other hand, an offset arrangement may be performed on the front side. In short, the offset arrangement may be performed in a direction in which the yarn is bent. Furthermore, the type and position of the thread guide portion, the shape of the thread guide member of the thread presence / absence detection device, the shape of the thread hook groove of the sewing machine main body, and the like are also arbitrary, and other specific detailed structures and the like can be appropriately changed. Of course, it is.

[0027]

As described above, according to the apparatus for detecting the presence or absence of a thread in a sewing machine according to the first aspect of the present invention, the thread penetrates the optical path connecting the light emitting section and the light receiving section in a direction crossing over a predetermined length. In the fine thread guide groove, the presence or absence of the upper thread that blocks light from the light emitting section can be detected.For example, even if the upper thread is slack, the presence of the upper thread can be reliably detected. It is hard to receive, and the presence or absence of the yarn can be reliably detected.

According to the second aspect of the present invention, since the thread guide member having the thread insertion opening continuous with the thread guide groove is provided, the effect obtained by the first aspect of the present invention. In addition, the upper thread can be passed through the thread guide groove by simply inserting the upper thread into the thread insertion opening with respect to the thread guide member,
That is, there is an advantage that the yarn can be easily set in the yarn presence detecting device.

According to the third aspect of the present invention, a thread guide groove is offset to one side with respect to a line connecting two thread guide portions of a sewing machine main body, and a light emitting portion is provided. Since the thread guide member is arranged so that the optical path connecting the light receiving portion and the offset direction are substantially along, the upper thread can be stably held in the thread guide groove during rotation of the sewing machine in addition to the effect obtained by the invention according to claim 1 or 2. And can be located
Therefore, there is an advantage that the presence of the upper thread can be reliably detected.

According to the thread detecting device for a sewing machine according to the fourth aspect of the present invention, a thread guide groove and a thread hooking groove for guiding the upper thread into the thread inserting opening are provided on the surface of the sewing machine. Since the upper thread is provided, in addition to the effect obtained by the third aspect of the present invention, the upper thread can be hooked on the two thread guide portions only by moving the upper thread along the thread hooking groove on the surface of the sewing machine main body. At the same time, there is an advantage that the thread can be passed through the thread guide groove from the thread insertion opening.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a sewing machine to which a yarn presence / absence detecting device as an example to which the present invention is applied is attached.

FIG. 2 is an exploded perspective view of the yarn presence / absence detection device of FIG.

FIGS. 3A and 3B show the relationship between the yarn presence / absence detecting device of FIG. 1 and the upper yarn, wherein FIG. 3A is a plan view taken along the center and FIG.

FIG. 4 is a diagram illustrating an example of a voltage change of a light receiving unit in the yarn presence / absence detecting device of FIG. 1;

[Explanation of symbols]

 A Upper thread 1 Sewing machine main body 2 Thread sesame (thread winding) 3 Thread sesame side thread guide section 4 Face plate side thread guide section 5 Face plate 6 Thread tensioner 7 Thread take-up spring 8 Balance 9 Needle 10 Thread guide member 11 Thread guide body 12 Light emitting section 14 Light receiving unit 16 Thread insertion opening 17 Thread guide groove 21 Thread guide cover 22 Upper plate 23 Side plate 26 Thread insertion opening 27 Thread guide groove 31 Thread catch groove

Claims (4)

[Claims] An apparatus for detecting the presence or absence of a needle thread on a sewing machine, comprising: a light emitting unit; a light receiving unit receiving light from the light emitting unit; and a light path connecting the light emitting unit and the light receiving unit. A thread guide member having a thin thread guide groove penetrating in a direction intersecting over a predetermined length, and passing the upper thread through the thread guide groove, and receiving light according to the presence or absence of the upper thread in the thread guide groove. An apparatus for detecting the presence or absence of a thread in a sewing machine, comprising detecting a change in an amount and detecting the presence or absence of an upper thread. 2. The sewing machine according to claim 1, wherein the thread guide member has a thread insertion opening which is bent and communicates with the thread guide groove and opens outward. Yarn detection device. 3. The thread guide groove is arranged at a position offset to one side with respect to a line segment connecting two thread guide portions provided on a sewing machine main body, and the thread is arranged so that the optical path and the offset direction are substantially along. The sewing machine thread presence / absence detection device according to claim 1 or 2, wherein a guide member is disposed. 4. A thread groove for guiding the upper thread to the thread guide section and the thread insertion opening is provided on the surface of the sewing machine body.
A thread detection device for the sewing machine according to the above.