JP5965371B2 - Lower thread remaining amount detection device for sewing machine - Google Patents

Description

  The present invention relates to a lower thread remaining amount detection device for a sewing machine that detects a remaining amount of a lower thread wound around a bobbin accommodated in a sewing machine hook.

  When sewing with the sewing machine, the remaining amount of bobbin thread wound around the bobbin is insufficient to prevent the sewing product from being re-sewn or defective sewing. There has been proposed a lower thread remaining amount detection device that detects and notifies that. As an example, for example, those disclosed in Patent Document 1, Patent Document 2, and Patent Document 3 have been proposed.

  The lower thread remaining amount detection device disclosed in Patent Document 1 or Patent Document 2 presses the tip of a detection rod that is advanced and retracted by a linear actuator against the outer peripheral portion of a thread wound around a bobbin, and the detection rod is the outer peripheral portion. The lower thread remaining amount can be detected on the basis of the position information in contact with the thread. The lower thread remaining amount detecting device described in Patent Document 3 radiates predetermined light from the light emitting unit toward the outer peripheral surface of the bobbin lower thread bundle and reflects the reflected light from the outer peripheral surface of the bobbin winding portion. The position of the outer peripheral surface is detected by collecting the light at the light collecting portion and receiving the light by the light receiving portion, thereby detecting the lower thread remaining amount wound around the bobbin. It was.

  However, when using the detection apparatus described in Patent Document 1 or Patent Document 2, there is a problem that a measurement error occurs depending on the degree of the pressing force of the detection rod. For this reason, the threshold value has to be increased, and the length of the thread to be discarded becomes unnecessarily long. Further, since the detection device described in Patent Document 1 has to stop the sewing machine in order for the lower thread remaining amount to be detected, there is a problem that the operation efficiency of the sewing machine is poor. On the other hand, the detection device described in Patent Document 2 has an advantage that the operation efficiency of the sewing machine can be improved because the lower thread remaining amount can be detected even while the sewing machine is operating. However, when the detection device described in Patent Document 2 is used, the detection rod may damage the lower thread because the detection bar is brought into contact with the lower thread wound around the rotating bobbin. Also, the detection bar and the lower thread may be damaged. There was also a risk that the frictional noise generated when rubbing with each other would generate noise.

  On the other hand, since the detection device described in Patent Document 3 optically detects the lower thread remaining amount, there is an advantage that the lower thread remaining amount can be detected without causing a problem as in the contact type detection device. there were. However, even with such a detection device, there are the following problems. That is, as shown in FIG. 15, the lower thread remaining amount detecting device a irradiates light from the light emitting portion e toward the outer peripheral surface d of the wound yarn portion c wound around the bobbin b, The light reflected by d is received by the light receiving portion f, and the position of the outer peripheral surface d of the bobbin portion c of the bobbin b is determined by triangulation based on the light receiving position information of the light output from the light receiving portion f. It was made to measure. Then, by associating the position information of the reflected light hitting the light receiving portion f and the position of the outer peripheral surface d, the thickness of the wound portion c can be detected, and thereby the thickness of the wound portion c can be determined. The corresponding lower thread remaining amount can be detected.

  By the way, since the thickness of the winding portion c changes according to the amount of the lower yarn wound around the bobbin b, the position of the outer peripheral surface d of the winding portion c changes according to the remaining amount of the lower yarn of the bobbin. Become. Then, as the position of the outer peripheral surface d of the wound yarn portion c where the irradiation light is reflected changes, the position where the reflected light hits the light receiving portion f also changes.

  Now, as schematically shown in FIG. 16A, when the lower thread j is wound on the outer peripheral surface h of the winding shaft g of the bobbin b over its entire width, the light emitting portion e The light receiving part f receives light reflected from the outer peripheral surface d1 of the fourth roll, and the lower thread remaining amount can be correctly detected from the light receiving position information of the light output from the light receiving part f. And for example, as shown in FIG. 16B, even if the lower thread j of the fourth roll is wound only on a part of the width of the winding shaft g, the irradiation light is irradiated on the outer peripheral surface d1 of the fourth roll. If the light is reflected and received by the light receiving unit f, it is detected that the bobbin has four lower threads wound on the bobbin. However, in actuality, since the fourth roll exists only in a part seen in the width direction of the winding shaft g, the detected lower thread remaining amount is different from the actual lower thread remaining amount. Accordingly, if the sewing machine continues sewing based on the lower thread remaining amount detection result, there may be a case where the lower thread disappears in the middle of sewing and a sewing failure occurs.

  Further, as shown in FIG. 17, for example, when the lower thread is cut after the predetermined sewing is completed, the bobbin b is idling, so that the lower thread j wound around the bobbin b is loosened. May have. In such a case, for example, as shown in FIG. 17, if the irradiation light is reflected by the surface m of the slack portion k of the lower thread and received by the light receiving portion f, the remaining amount of the lower thread is larger than the actual amount. It will be detected as a thing. In this case as well, a sewing failure occurs as described above.

Japanese Utility Model Publication No. 63-136591 JP-A-9-56950 JP 2007-222555 A

  The present invention has been developed in view of the above-mentioned conventional problems, and it is possible to more accurately detect the lower thread remaining amount wound around the bobbin accommodated in the hook of the sewing machine in a non-contact manner. An object of the present invention is to provide a bobbin thread remaining amount detection device that can perform sewing.

In order to solve the above problems, the present invention employs the following means.
That is, the first aspect of the lower thread remaining amount detecting device (hereinafter referred to as the lower thread remaining amount detecting device) according to the present invention is a bobbin that accommodates a bobbin around which a lower thread is wound so as to be rotatable about its axis. A lower thread remaining amount detecting means for detecting a remaining amount of lower thread wound around the bobbin in a sewing machine including an inner hook that holds the case inside and a outer hook that has a sword tip and is rotatable around the outer periphery of the inner hook. The bobbin thread remaining amount detecting device for the sewing machine to detect by the following, a first measurement opening is provided on the peripheral wall portion of the bobbin case so as to face the outer peripheral surface of the winding portion wound around the bobbin, The peripheral wall portion of the inner hook that houses the bobbin case is provided with a second measurement opening that can communicate with the first measurement opening, and the peripheral wall portion of the outer pot is interrupted, The discontinuous openings between the both ends of the peripheral wall portion are the first and second measurement openings. There is a third measurement aperture that can through. The lower thread remaining amount detecting means is configured using a triangulation optical measuring instrument, and the first, second, and third measurement openings are connected to form a communication measurement opening. Then, the irradiation light from the irradiation part of the optical measuring instrument is irradiated toward the outer peripheral surface of the bobbin winding part through the communication measurement opening, and the reflected light reflected by the outer peripheral surface is Based on the principle of triangulation based on the light receiving position information of the light output from the light receiving portion, the outer peripheral surface of the bobbin portion of the bobbin is received by the light receiving portion of the optical measuring instrument through the communication measurement opening. The measurement is performed a plurality of times, and the lowest measurement value among the plurality of measurement values is detected as the position of the outer peripheral surface of the winding portion. Yes. And a discriminating device for discriminating whether or not the remaining amount of bobbin thread detected based on the lowest measured value has a necessary bobbin thread amount that enables one sewing of the sewing machine, Through the communication measurement opening, air is blown against the portion of the outer peripheral surface of the bobbin winding portion facing the communication measurement opening, and the air is applied to the slack portion of the lower thread generated on the outer peripheral surface. In addition, an air blow device is provided for removing the slack portion from the facing portion so that the irradiation light does not hit the slack portion .

A second aspect of the lower thread remaining amount detecting device according to the present invention includes an inner hook that holds a bobbin case that accommodates a bobbin around which a lower thread is wound so as to be rotatable about its axis, and a sword tip. A lower thread remaining amount detection device for a sewing machine that detects the remaining amount of lower thread wound around the bobbin by a lower thread remaining amount detecting means in a sewing machine including an outer hook that can rotate the outer periphery of the inner hook, A first measurement opening is provided in the peripheral wall portion of the bobbin case so as to face the outer peripheral surface of the winding portion wound around the bobbin, and the peripheral wall portion of the inner hook that houses the bobbin case A second measurement opening that can communicate with the first measurement opening is provided, and the peripheral wall portion of the outer pot is interrupted. 1 and 3rd measurement opening which can be communicated with the 2nd measurement opening. Ryo and when the thread cutting signal is output, the first, second, third measuring opening is made as communicating the measurement aperture is formed in communication. The lower thread remaining amount detecting means is configured using a triangulation optical measuring instrument, and the first, second, and third measurement openings are connected to form a communication measurement opening. Then, the irradiation light from the irradiation unit of the optical measuring instrument is irradiated toward the outer peripheral surface of the bobbin winding portion through the communication measurement opening, and the reflected light reflected by the outer peripheral surface is Based on the principle of triangulation based on the light receiving position information of the light output from the light receiving portion, the outer peripheral surface of the bobbin portion of the bobbin is received by the light receiving portion of the optical measuring instrument through the communication measurement opening. It measures the position of. The measurement is started in synchronization with the output of the thread trimming signal in a state where the communication measurement opening is formed, and the measurement is performed after the thread trimming signal is output and the lower thread. Is performed a plurality of times in the time period until the cutting of the wire is started, and the lowest measured value among the measured values of the plurality of times is detected as the position of the outer circumferential surface of the wound portion. And a discriminating device for discriminating whether or not the remaining amount of bobbin thread detected based on the lowest measured value has a necessary bobbin thread amount that enables one sewing of the sewing machine, and The air is blown through the communication measurement opening to the portion of the outer peripheral surface of the bobbin winding portion facing the communication measurement opening, and the air is applied to the slack portion of the lower thread generated on the outer peripheral surface. The slack portion is applied so that the irradiation light does not hit the slack portion. Is characterized in that said opposing to order air blow device as away of a portion is provided so as.

A third aspect of the lower thread remaining amount detecting device according to the present invention includes an inner hook that holds a bobbin case that accommodates a bobbin around which a lower thread is wound so as to be rotatable about its axis, and a sword tip. A lower thread remaining amount detection device for a sewing machine that detects the remaining amount of lower thread wound around the bobbin by a lower thread remaining amount detecting means in a sewing machine including an outer hook that can rotate the outer periphery of the inner hook, A first measurement opening is provided in the peripheral wall portion of the bobbin case so as to face the outer peripheral surface of the winding portion wound around the bobbin, and the peripheral wall portion of the inner hook that houses the bobbin case A second measurement opening that can communicate with the first measurement opening is provided, and the peripheral wall portion of the outer pot is interrupted. 1. A third measurement opening that can communicate with the second measurement opening. When the activation signal is output, the first, second, third measuring opening is made as communicating the measurement aperture is formed in communication. The lower thread remaining amount detecting means is configured using a triangulation optical measuring instrument, and the first, second, and third measurement openings are connected to form a communication measurement opening. Then, the irradiation light from the irradiation unit of the optical measuring instrument is irradiated toward the outer peripheral surface of the bobbin winding portion through the communication measurement opening, and the reflected light reflected by the outer peripheral surface is Based on the principle of triangulation based on the light receiving position information of the light output from the light receiving portion, the outer peripheral surface of the bobbin portion of the bobbin is received by the light receiving portion of the optical measuring instrument through the communication measurement opening. The measurement is started in synchronism with the output of the activation signal and is performed a plurality of times, and the lowest measured value among the measured values of the plurality of times is determined. The position of the outer peripheral surface of the wound yarn portion is detected. And a discriminating device for discriminating whether or not the remaining amount of bobbin thread detected based on the lowest measured value has a necessary bobbin thread amount that enables one sewing of the sewing machine, Through the communication measurement opening, air is blown against the portion of the outer peripheral surface of the bobbin winding portion facing the communication measurement opening, and the air is applied to the slack portion of the lower thread generated on the outer peripheral surface. the該弛viewed portion Te, the irradiation light is characterized in that the air blow device to order as away of from the opposite portions are provided so as not hit the該弛viewed portion.

A fourth aspect of the lower thread remaining amount detecting device according to the present invention includes an inner hook that holds a bobbin case that accommodates a bobbin around which a lower thread is wound so as to be rotatable about its axis, and a sword tip. A lower thread remaining amount detection device for a sewing machine that detects the remaining amount of lower thread wound around the bobbin by a lower thread remaining amount detecting means in a sewing machine including an outer hook that can rotate the outer periphery of the inner hook, A first measurement opening is provided in the peripheral wall portion of the bobbin case so as to face the outer peripheral surface of the winding portion wound around the bobbin, and the peripheral wall portion of the inner hook that houses the bobbin case A second measurement opening that can communicate with the first measurement opening is provided, and the peripheral wall portion of the outer pot is interrupted. 1 and 3rd measurement opening which can be communicated with the 2nd measurement opening. When the thread trimming signal is output, the first, second, and third measurement openings communicate with each other to form a communication measurement opening, and when the sewing machine start signal is output, The first, second and third measurement openings communicate with each other to form a communication measurement opening. The lower thread remaining amount detecting means is configured using a triangulation optical measuring instrument, and the first, second, and third measurement openings are connected to form a communication measurement opening. Then, the irradiation light from the irradiation unit of the optical measuring instrument is irradiated toward the outer peripheral surface of the bobbin winding portion through the communication measurement opening, and the reflected light reflected by the outer peripheral surface is Based on the principle of triangulation based on the light receiving position information of the light output from the light receiving portion, the outer peripheral surface of the bobbin portion of the bobbin is received by the light receiving portion of the optical measuring instrument through the communication measurement opening. The measurement is started in synchronization with the output of the thread trimming signal in a state where the communication measurement opening is formed, and the measurement is performed when the thread trimming signal is Is output and until the lower thread starts to be cut. Is performed a plurality of times in the time zone, and the lowest measured value of the measured values of the plurality of times is detected as the position of the outer peripheral surface of the wound portion, and the measurement is performed as described above. It is started in synchronization with the output of the start signal and is performed a plurality of times, and the lowest measured value among the measured values of the plurality of times is detected as the position of the outer peripheral surface of the winding portion. ing. And a discriminating device for discriminating whether or not the remaining amount of bobbin thread detected based on the lowest measured value has a necessary bobbin thread amount that enables one sewing of the sewing machine, Through the communication measurement opening, air is blown against the portion of the outer peripheral surface of the bobbin winding portion facing the communication measurement opening, and the air is applied to the slack portion of the lower thread generated on the outer peripheral surface. the該弛viewed portion Te, the irradiation light is characterized in that the air blow device to order as away of from the opposite portions are provided so as not hit the該弛viewed portion.

A fifth aspect of the lower thread remaining amount detecting device according to the present invention is the peripheral wall portion of the fifth aspect that is not covered by the outer hook of the inner hook when the thread trimming signal is output. The second measurement opening is provided in the peripheral wall portion of the inner hook that is not covered by the outer hook when the start signal is output, and the second wall is provided in the peripheral wall portion of the bobbin case. The first measurement opening that can communicate with the measurement opening is provided.

According to a sixth aspect of the lower thread remaining amount detection device according to the present invention, in any one of the first to fifth aspects, the cover portion surface of the irradiation unit and the cover portion surface of the light receiving unit of the optical measuring instrument. A spray nozzle for spraying air is provided.

According to a seventh aspect of the lower thread remaining amount detection device according to the present invention, in any one of the first, second, third, fourth, and fifth aspects, the cover portion of the irradiation unit of the optical measuring instrument. A blowing nozzle for blowing air to the surface and the cover surface of the light receiving unit is provided, and a part of the air supplied from the same air supply source is supplied to the air blowing device, while the remaining air is The air is supplied to the spray nozzle, and the supply of the air is intermittently performed in accordance with the formation timing of the communication measurement opening.

An eighth aspect of the lower thread remaining amount detection device according to the present invention is characterized in that, in any of the first to seventh aspects, the measurement is performed a plurality of times per 1/100 second. is there.

The present invention has the following excellent effects.
(1) The bobbin thread remaining amount detecting device according to the present invention measures the position of the outer peripheral surface of the bobbin winding portion using a triangulation optical measuring instrument, and this measurement is performed a plurality of times. In particular, the lowest measured value of the measured values of the plurality of times is detected as the position of the outer peripheral surface of the wound yarn portion. Therefore, according to the present invention, the measurement accuracy can be further improved as compared with the conventional device that detects the lower thread remaining amount based on the measurement value obtained by only one measurement.

  By the way, the sewing machine has a fate that the lower thread is loosened. For example, when the bobbin thread is cut after the predetermined sewing is completed, the bobbin is in an idling state for several rotations at the time of the cutting, so that the thread is likely to loosen on the outer surface of the wound thread portion. . In addition, even during sewing, the bobbin thread may be loosened due to idling of the bobbin due to an inertial action or the like during cloth feeding. For this reason, when the slack yarn is wound around the bobbin several times, it is an error even if the lowest measured value of the measured values can be measured as the position of the outer peripheral surface of the wound portion. Operation may occur.

  Therefore, in the present invention, an air blowing device is provided for blowing air to the outer peripheral surface of the bobbin winding portion through the communication measurement opening formed by communicating the first, second, and third measurement openings. ing. By blowing air with the air blowing device, it becomes easy to remove the slack portion of the lower thread from the portion of the outer peripheral surface facing the communication measurement opening, so that the minimum value can be measured without being affected by the slack of the thread as much as possible. Thus, the measurement accuracy of the outer peripheral surface of the wound yarn portion can be further improved.

(2) According to the present invention, since the lower thread remaining amount can be detected in a non-contact manner, there is no possibility of damaging the lower thread wound around the bobbin as in Patent Document 1 and Patent Document 2.

(3) The measurement is started in synchronization with the output of the thread trimming signal, and when the thread trimming signal is output, the first, second and third measurement openings communicate with each other. When the measurement opening is formed and the measurement is performed after the thread trimming signal is output and in the time zone until the lower thread cutting starts, the lower thread is sewn. Since it is in a state of being connected to an object, usually the slack of the lower thread does not occur on the outer peripheral surface 27 of the bobbin winding portion 26. Therefore, it is possible to perform measurement in a state where the occurrence of loosening of the lower thread in the bobbin winding portion is as small as possible, and more accurate measurement can be performed even while the sewing machine is in operation.

  In this case, when the air blow device having the same configuration as described above is provided, even if the bobbin thread is loosened due to the idling of the bobbin due to inertia or the like, the air blow device causes the outer periphery of the bobbin winding portion to be By blowing air onto the surface, in the same manner as described above, it becomes easy to remove the slack portion of the lower thread from the portion of the outer peripheral surface facing the communication measurement opening, and therefore the state is not affected by the slack of the thread as much as possible. Thus, the minimum value can be measured, and the measurement accuracy of the outer peripheral surface of the wound portion can be further improved.

(4) The measurement is started in synchronization with the output of the start signal of the sewing machine, and when the start signal is output, the first, second, and third measurement openings communicate with each other. When configured so that a communication measurement opening is formed, and in the same manner as described above, an air blow device for blowing air to the outer peripheral surface of the bobbin winding portion through the communication measurement opening is provided. Even if the lower thread is loosened by cutting the lower thread after the completion of the predetermined sewing, the air blow device blows air against the outer peripheral surface of the wound thread portion so that it is not affected by the slack of the thread as much as possible. Therefore, the measurement accuracy of the outer peripheral surface of the wound portion can be improved. In this way, when it is configured so that it can be measured even at the beginning of sewing, it is necessary to enable at least one sewing of the sewing machine when sewing is resumed when the operator changes or when a power failure occurs. Whether or not the amount remains on the bobbin can be confirmed even when the sewing machine is started. As a result, the remaining amount of the lower thread can be carefully detected, and the occurrence of poor sewing can be more reliably prevented.

(5) A peripheral wall portion that is not covered by the outer hook of the inner hook when the thread trimming signal is output, and is covered by the outer hook of the inner hook when the start signal is output. When the second measurement opening is provided in the peripheral wall portion that is not provided, and the first measurement opening that can communicate with the second measurement opening is provided in the peripheral wall portion of the bobbin case,
There is an economy that the first measurement and the second measurement can be performed by using one optical measuring instrument.

(6) When providing an air blow device for blowing air to the surface of the cover of the irradiation unit and the surface of the cover of the light receiving unit of the optical measuring instrument, dust, lubricating oil, or the like is applied to the irradiation unit or the light receiving unit. It can be difficult to adhere and measurement errors due to the adhesion can be prevented.

(7) In particular, a part of the air supplied from the same air supply source is supplied to the air blowing device, while the remaining air is directed toward the cover part surface of the irradiation part and the cover part surface of the light receiving part. When the air is blown and the air is blown intermittently in accordance with the formation timing of the communication measurement opening, the bobbin winding portion is formed using the same air supply source. Since the air can be blown to the outer peripheral surface of the optical device and the air can be blown toward the cover surface of each of the irradiation unit and the light receiving unit of the optical measuring instrument, the apparatus can be economically achieved. Further, by intermittently spraying these airs, there is an economy that can reduce air consumption as much as possible.

(8) If the time of the plurality of times of measurement is long, the productivity is deteriorated. However, for example, if it is performed a plurality of times per 1/100 seconds, the required measurement can be performed without reducing the productivity.

It is a front view which shows the lower thread residual amount detection apparatus of the sewing machine which concerns on this invention. FIG. It is explanatory drawing explaining the detection method of the bobbin thread remaining amount started in synchronization with the output of a thread trimming signal. It is explanatory drawing explaining the detection method of a bobbin thread remaining amount at the time of starting of a sewing machine. FIG. It is explanatory drawing explaining the detection method of the bobbin thread remaining amount started in synchronization with the output of the starting signal of a sewing machine. It is a perspective view which shows a sewing machine hook, a bobbin, and a bobbin case. It is a perspective view which shows a bobbin and a bobbin case. It is sectional drawing which shows the state in which the bobbin was accommodated in the bobbin case. It is a perspective view which shows a communication measurement opening. It is explanatory drawing explaining the formation site | part of a communication measurement opening. It is explanatory drawing explaining the detection timing of the bobbin thread remaining amount performed in synchronization with the output of a thread trimming signal. It is explanatory drawing explaining the effect | action of the air blowing by an air blow apparatus, and the slack state of the lower thread in a wound thread part. It is explanatory drawing explaining the advantage of detecting the lowest measured value of the measured value of several times as a position of the outer peripheral surface of a wound part. It is explanatory drawing explaining the conventional lower thread residual amount detection apparatus. It is explanatory drawing explaining the problem of a conventional apparatus. It is explanatory drawing explaining the problem of a conventional apparatus.

  1 to 3 and 4 to 6, the bobbin thread remaining amount detecting device 1 according to the present invention holds a bobbin case 5 that accommodates a bobbin 3 around which a bobbin 2 is wound so as to be rotatable about its axis. The remaining amount of the lower thread 2 wound around the bobbin 3 in the sewing machine 8 that includes the inner hook 6 that has the sword tip 7 and the outer hook 9 that can rotate the outer periphery of the inner hook 6 The inner hook 6 and the outer hook 9 constitute a sewing machine hook 11 which is detected by a detecting means 10.

  As shown in FIGS. 2 to 3, FIGS. 5 to 6, and FIGS. 7 to 8, a first measurement opening 13 is provided in the peripheral wall portion 12 (FIG. 7) of the bobbin case 5. A second measurement opening 16 is provided in the peripheral wall portion 15 of the inner hook 6 to be accommodated, and a third measurement opening 19 is provided in the peripheral wall portion 17 of the outer hook 9.

  In the present embodiment, the lower thread remaining amount detecting means 10 is configured by using an optical measuring device 21 as a laser displacement meter of a triangulation method applying a triangulation method, and FIGS. 5 to 6, the first, second, and third measurement openings 13, 16, and 19 communicate with each other to form the communication measurement opening 22, and then from the irradiation unit 23 of the optical measuring instrument 21. Irradiation light 25 is irradiated toward the outer peripheral surface 27 of the bobbin portion 26 of the bobbin 3 through the communication measurement opening 22, and reflected light 29 reflected by the outer peripheral surface 27 is reflected in the communication measurement opening 22. The light is received by the light receiving unit 30 of the optical measuring instrument 21 through the light.

  The bobbin thread remaining amount detecting means 10 determines the position of the outer circumferential surface 27 of the bobbin portion 26 of the bobbin 3 based on the principle of triangulation based on the light receiving position information of the light output from the light receiving portion 30. The measurement is performed a plurality of times, and the lowest measurement value of the measurement values of the plurality of times is detected as the position of the outer peripheral surface 27 of the winding portion 26. .

  And a discriminating device for discriminating whether the lower thread remaining amount detected based on the lowest measured value has a necessary lower thread amount that enables one sewing of the sewing machine, and An air blowing device 31 for blowing air to the outer peripheral surface 27 of the bobbin portion 26 of the bobbin 3 through the communication measurement opening 22 is provided. The nozzle diameter at the tip of the spray nozzle 32 of the air blow device 31 is set to 1 mm, for example.

  Hereinafter, this will be described more specifically. FIG. 7 is a perspective view showing the sewing machine hook 11, the bobbin 3, and the bobbin case 5 in a sewing machine 8 having a vertical full rotation hook in which the outer hook 9 rotates counterclockwise F (FIG. 1). 8 is a perspective view showing the bobbin 3 and the bobbin case 5, and FIG. 9 is a cross-sectional view showing a state in which the bobbin 3 is accommodated in the bobbin case 5.

  In the present embodiment, the sewing machine 8 is configured as a lockstitch sewing machine as shown in FIG. 1, and is sewn with the upper thread 33 and the lower thread 2, and for example, an airbag or a seat belt is sewn. 7-9, for example, the bobbin 3 is provided with concentric ridges 36, 36 on the outer surfaces of the left and right ends of the bobbin cylinder 35, and the bobbin cylinder 35 has its axis on the axis. A mounting hole 37 is penetrating along. The lower thread 2 wound around the bobbin 35 of the bobbin 3 is a yarn that is usually used for this purpose in view of the fact that the main sewing machine sews an airbag or a seat belt. A thread with a diameter of about 0.5 mm.

  In the present embodiment, the bobbin case 5 has, as shown in FIGS. 7 to 9, a front surface of the bobbin case body 41 of the bobbin case body 41 having a housing space 40 with an open rear end 39. A support cylinder 44 protrudes from the inner surface 43 of the portion 42, and a support hole 45 extends through the support cylinder 44 along its axis. Then, as the support cylinder 44 is inserted into the mounting hole 37, the bobbin 3 is accommodated in the accommodation space 40 so as to be rotatable about its axis as shown in FIG. Further, as shown in FIG. 9, the bobbin case 5 is inserted into the support hole 45 of the support cylinder 44 through a support shaft 46 protruding from the center of the inner hook 6. Supported by the hook 6. Further, as shown in FIG. 7, the outer surface 47 of the front surface portion 42 of the bobbin case main body 41 has a lock opening that can communicate with the opening end surface 49 of the support tube 44 (FIG. 8) so as to cross the central portion. A lever 51 having 50 is provided. Then, as shown in FIG. 9, the support cylinder 44 can be attached to and detached from the support shaft 46 by tilting the lever 51, and by tilting the lever 51 as shown in FIG. As shown, the bobbin case 5 is locked while being supported by the inner hook 6.

  Thus, the sewing machine supplies the lower thread 2 by the bobbin 3 accommodated in the bobbin case 5 and counterclockwise as indicated by the arrow F in FIG. 1 during one up and down movement of the sewing needle 52 (FIG. 1). The upper thread 33 squeezed by the sword tip 7 of the outer hook 9 rotating in a loop forms a loop and passes through the inner hook 6 once. At this time, the front thread portion of the upper thread 33 in the loop is The bobbin case 5 housed in the inner hook 6 is configured to cross the surface 55 of the bobbin case 5 in the counterclockwise direction F.

  As shown in FIG. 7B, the first measurement opening 13 is formed in the peripheral wall portion 12 of the bobbin case 5 so as to face the outer peripheral surface 27 of the winding portion 26 wound around the bobbin 3. Is provided. In the present embodiment, the first measurement opening 13 is provided close to the front surface portion 42 as shown in FIG. The width of the first measurement opening 13 in the front-rear direction is set to about 4 mm, for example, and the length in the circumferential direction is set to about 12 mm, for example. Further, as shown in FIGS. 2 to 3, 5, 7, and 10, the peripheral wall portion 15 of the inner hook 6 that accommodates the bobbin case 5 completely includes the first measurement opening 13. A second measurement aperture 16 is provided which can communicate with the second measurement aperture 16. Further, the peripheral wall portion 17 of the outer hook 9 is interrupted, and as shown in FIGS. 2 to 3, 7, and 10, the interrupted opening 56 is formed between both ends of the peripheral wall portion 17, that is, one opening end portion. A discontinuous opening 56 that opens in an angular range of approximately 180 degrees completely includes the first and second measurement openings 13 and 16 between 57 and the sword tip 7 provided on the other opening end side. Thus, the third measurement opening 19 which can communicate with this is configured.

  In this embodiment, when the sewing is completed and the thread trimming signal is output, the sword tip 7 is substantially at the lowermost position 59 as shown in FIG. 2, while when the sewing machine start signal is output. As shown in FIG. 5, the sword tip 7 is at a position 60 (hereinafter, also referred to as an upper end side position) that is too far from the uppermost position when viewed counterclockwise. For this reason, when the measurement is performed by the lower thread remaining amount detecting means 10, for example, as shown in FIGS. 2, 5, and 10, the lower right portion of the peripheral wall portion 15 of the inner hook 6 is the outer hook. 9 is not covered. Therefore, the second measurement opening 16 can be provided in the peripheral wall portion 61 of the inner hook 6 not covered with the outer hook 9 in this way. If the first measurement opening 13 is provided in the peripheral wall portion 12 of the bobbin case 5 so as to communicate with the second measurement opening 16, as shown in FIG. 3, FIG. 6, and FIG. The first, second, and third measurement openings 13, 16, and 19 are communicated to form the communication measurement opening 22.

  In short, in the present embodiment, the peripheral wall portion 61a (FIG. 2) not covered by the outer hook 9 of the inner hook 6 at the time of output of the thread trimming signal, and at the time of output of the start signal. The second measurement opening 16 is provided in the peripheral wall portion 61b (FIG. 5) of the inner hook 6 which is not covered by the outer hook 9, that is, the peripheral wall portion 61 (FIG. 2), and the bobbin case 5 The peripheral wall portion 12 is provided with the first measurement opening 13 that can communicate with the second measurement opening 16.

  More specifically, the sword tip 7 is substantially directly under the thread trimming, that is, at the substantially lower end position 59 (FIG. 2), and at the upper end side position 60 (FIG. 5) when the sewing machine is activated. Therefore, at the time of thread trimming, as shown in FIG. 2, the substantially right half of the peripheral wall portion 61 of the inner hook 6 is open. Further, at the time of activation, as shown in FIG. 5, the substantially lower half of the peripheral wall portion 61 of the inner hook 6 is open. Therefore, in the present embodiment, the bobbin case 5 is provided with the second measurement opening 16 in the inner hook 6 at the portion where the substantially right half and the substantially lower half are overlapped with each other. One measurement opening 13 is provided. FIG. 11 is an explanatory diagram for explaining this overlapping portion, and the outer hook 9 at the time of outputting the thread trimming signal is indicated by a thick solid line, and the outer hook 9 at the time of starting the sewing machine is indicated by a thin solid line. The overlapping portion of the substantially right half and the substantially lower half is denoted by reference numeral 64. The communication measurement opening 22 is formed by the overlapping portion 64. As a result, a single optical measurement device 21 can perform a first measurement and a second measurement described later.

  In the present embodiment, the lower thread remaining amount detecting means 10 is configured by using the optical measuring instrument 21 as a triangulation type laser displacement meter 21a as shown in FIG. The laser displacement meter 21 a is fixed at a fixed position in the vicinity of the sewing machine hook 11, and irradiates the irradiation laser beam 62 toward the outer peripheral surface 27 of the bobbin portion 26 of the bobbin 3 through the communication measurement opening 22. The irradiation unit 23 for irradiation and the light receiving unit 30 for receiving the reflected laser beam 65 reflected by the outer peripheral surface 27 through the communication measurement opening 22 are provided.

  2 to 3, the irradiation laser beam 62 is irradiated from the irradiation unit 63 of the laser displacement meter 21 a toward the center of the support shaft 46 through the communication measurement opening 22, and the winding unit 26 has the above-described configuration. The reflected laser beam 65 reflected by the outer peripheral surface 27 is shown as being received by the light receiving unit 66 of the laser displacement meter 21a through the communication measurement opening 22. In this embodiment, the outer peripheral surface 27 is irradiated with spot light. In the present embodiment, since the arrangement state of the first, second, and third measurement openings 13, 16, and 19 is specified as described above, these three measurement openings 13, 16, and 19 are surely arranged. The first measurement and the second measurement which will be described later can be performed using one optical measuring instrument 21.

  Based on the principle of triangulation based on the light receiving position information of the light output from the light receiving unit 30, the position of the outer circumferential surface 27 of the winding unit 26 with respect to the outer circumferential surface 67 of the bobbin winding 35 (hereinafter referred to as the winding unit 26). Can be measured). However, by associating the surface height H (FIGS. 3 and 6) of the wound thread portion 26 with the remaining amount of the lower thread wound around the bobbin 3, the surface height of the wound thread portion 26 is increased. By the length H, the lower thread remaining amount wound around the bobbin 3 can be detected. The measurement value used for detecting the lower thread remaining amount is the lowest measurement value among the plurality of measurement values. The reason for performing the measurement a plurality of times is to prevent measurement errors. However, if the time for a plurality of measurements is long, the productivity is deteriorated. Therefore, the plurality of measurements are preferably performed in a short time. An example of this short time is 1/100 second. The reason why the lowest measured value is used is to detect the lower thread remaining amount more accurately. More specifically, there may be irregularities due to uneven winding of the yarn on the outer peripheral surface 27 of the wound yarn portion 26. This is to make the irregularities as difficult as possible to be affected, and the lower thread is loosened. In order to more accurately detect the remaining amount of the lower thread, excluding extreme measurement values such as when the reflected laser beam 65 on the surface 70 (FIG. 13A) of the portion 69 is received by the light receiving unit 30. is there.

  By the way, when the bobbin thread is cut after the predetermined sewing is completed, the bobbin 3 is in an idling state for several rotations at the time of the cutting, so as shown in FIG. Looseness of the lower thread has occurred on the outer peripheral surface 27 of the thread portion 26. Further, even during sewing, the bobbin thread may be loosened due to idling of the bobbin 3 due to an inertial action or the like during cloth feeding. Due to these causes, when the slack yarn is wound several times, malfunction may occur even if the lowest measured value of the measured values of the plurality of times can be measured as the position of the outer peripheral surface 27. . This is because if the measured value on the surface 70 of the slack portion 69 of the lower thread is detected as the minimum value, the surface height H of the wound thread portion 26 becomes larger than the actual height.

  In such a case, as shown in FIGS. 13B and 13C, from the blowing nozzle 32 of the air blowing device 31, the communication measurement opening 22 in the outer peripheral surface 27 is passed through the communication measurement opening 22. Air is blown toward the facing portion 27A. As a result, the slack portion 69 of the lower thread is moved to the left or right end portion 71a of the bobbin 35 as shown in FIG. 13B, or as shown in FIG. 13C. The slack portion 69 of the lower thread is moved away from the portion 27A of the outer peripheral surface 27 facing the communication measurement opening 22 by moving it separately to the left and right end sides 71a, 71b of the bobbin cylinder 35. It becomes easy. Therefore, even if the lower thread 2 wound around the bobbin 3 is slack, it is possible to measure the minimum value without being affected by the slack of the thread as much as possible. Measurement accuracy can be improved.

  In this embodiment, as shown in FIGS. 2 and 5, a part of the air supplied from the same air supply source is supplied to the air blowing device 31, while the remaining air is shown in FIGS. 4-5, it is sprayed toward the cover surface 73 of the irradiation unit 23 and the cover surface 75 of the light receiving unit 30 of the laser displacement meter 21a through the adhesion preventing nozzle 72. Has been made. By this spraying, it is possible to make it difficult for dust, lubricating oil or the like to adhere to the cover surface 73, 75, and it is possible to prevent occurrence of measurement errors due to these adhesion. The air blowing may be performed continuously, but in the present embodiment, in order to minimize the amount of air consumption, the air is intermittently performed in accordance with the formation timing of the communication measurement opening 22. . In accordance with this timing, air is blown onto the cover portion surfaces 73 and 75. Note that the air blowing by the blowing nozzle 32 and the air blowing by the adhesion preventing nozzle 72 may be performed by separate air supply sources.

  The determination device determines whether or not the lower thread remaining amount detected based on the lowest measured value has a necessary lower thread amount that enables one sewing of the sewing machine. In the discriminating apparatus, the surface height H when the necessary lower thread amount enabling one sewing is wound around the bobbin winding 35 is set as a threshold value. When the measured surface height H falls below this threshold value, the notification means notifies, for example, by turning on a red lamp and sounding a buzzer. Here, the necessary lower thread amount refers to the lower thread amount obtained by adding the discarded thread amount to the necessary sewing lower thread amount consumed for one sewing. This amount of discarded thread is set so that the lower thread 2 does not slip out of the bobbin 35 of the bobbin 3 during sewing, and is set so that at least one turn remains in the bobbin 35. To do. More preferably, it is set with some allowance as will be described later in consideration of some measurement errors.

  Here, an example of determination of the remaining yarn amount by the determination device will be described. Now, for example, when sewing an airbag, if the thread thickness is 0.5 mm and the amount of lower thread necessary for sewing that allows one sewing of the sewing machine is 785 mm, the threshold value is 0. Suppose that it is set to 7 mm. The amount of lower thread required for sewing can be calculated by multiplying the sewing pitch by the number of stitches. In this case, if the surface height H of the wound thread portion 26 based on the lowest measured value is 0.8 mm, 785 mm, which is the amount of lower thread necessary for sewing, can be secured, and this necessary amount of lower thread is completely consumed. Even in such a state, the bobbin 35 of the bobbin 3 is in a state in which a bobbin thread is wound around the bobbin 35 with a length (for example, a length of about 800 mm) that secures friction and does not destabilize the sewing. . In this case, if the surface height of the wound thread portion 26 based on the minimum measured value is 0.69 mm, this is below the threshold value, so the discrimination device can sew one sewing machine. For example, a red lamp is lit and a buzzer sounds to notify that there is no necessary remaining amount of lower thread.

  Next, a specific measurement method using the laser displacement meter 21a will be described. In the present embodiment, the first measurement is performed after the thread trimming signal is output and until the lower thread is started to be cut, and at the time of starting the sewing machine to make the measurement more reliable. The second measurement will be described.

  First, the first measurement will be described. The first measurement is started in synchronization with the output of the thread trimming signal in a state where the communication measurement opening 22 is formed, and the measurement is performed after the thread trimming signal is output. In addition, for example, a plurality of times (for example, 5 times) per 1/100 second is performed in a time period until the lower thread is cut. FIG. 2 shows the position of the sword tip 7 of the outer hook 9 at the time when the thread trimming signal is output, and the sword tip 7 is at the substantially lowermost position 59. In this state, the communication measurement opening 22 is formed. The outer hook 9 rotates counterclockwise F in FIG. 2, and the plurality of measurements are performed in a time zone in which the blade tip 7 does not cover the communication measurement opening 22. During the measurement, it is essential that the communication measurement opening 22 for allowing the irradiation laser beam 62 and the reflected laser beam 65 to pass through is not covered with the sword tip 7. Therefore, in this embodiment, as shown in FIG. 12, the angle θ at which the sword tip 7 rotates counterclockwise until the sword tip 7 at the substantially lowermost position 59 reaches the communication measurement opening 22, It is set at 36 degrees with some margin. Now, assuming that 0.02 second is required for this rotation of 36 degrees in relation to the number of rotations of the sewing machine (for example, 400 rotations) at the time of thread trimming, the laser displacement meter 21a is operated 50 to 60 times during this period. taking measurement.

  The laser displacement meter 21a detects the lowest measured value among the measured values as the position of the outer peripheral surface 27 of the wound thread portion 26. Therefore, for example, as shown in FIG. 14, the lower thread 2 of the fourth roll is not wound around the entire width L of the outer peripheral surface 67 of the bobbin 35 of the bobbin 3 but is wound only around a part of the entire width L of the bobbin 35. Even if the detected value is the surface height H of the outer peripheral surface 27a that is one step lower as shown in FIG. 14 (A), more accurate measurement has been made. become. In this case, the lowest measured value detected also occurs when the surface height H of the outer peripheral surface 27b is one step higher as shown in FIG. In this way, depending on whether the outer circumferential surface 27a of the lower winding portion is the lowest measured value or the outer circumferential surface 27b of the higher winding portion is the lowest measured value, the surface height H is An error of about one turn will also occur. Therefore, it can be said that it is preferable to set the amount of the discarded yarn with a margin of one turn in consideration of the measurement error. This is the meaning of “setting with some allowance” described above.

  As described above, the first measurement is performed after the yarn trimming signal is output and during the time period until the lower yarn is started to be cut. In the time zone from when the thread trimming signal is output to when cutting of the lower thread is started, the lower thread is in a state of being connected to the sewing product, and therefore the outer peripheral surface 27 of the bobbin winding portion 26 is. In general, the lower thread is not loosened. Therefore, by performing the measurement during the time period, it is possible to perform measurement in a state where the occurrence of loosening of the lower thread in the wound thread portion 26 is as small as possible, and more accurate measurement can be performed even while the sewing machine is operating. However, even during sewing, as shown in FIG. 13A, for example, the bobbin thread may be loosened due to the idling of the bobbin due to an inertial action or the like during cloth feeding. Therefore, as shown by arrows in FIGS. 13B and 13C, the air blowing device 31 blows air to the outer peripheral surface 27 of the bobbin portion 26 of the bobbin 3 through the communication measurement opening 22.

  Accordingly, for example, as shown in FIGS. 13B and 13C, the lower thread loose portion 69 can be easily removed from the portion 22A of the outer peripheral surface 27 facing the communication measurement opening 22. Therefore, even if such slack occurs in the bobbin thread wound around the bobbin 3, the minimum value can be measured in a state where it is not affected by the slack of the thread as much as possible. 27 measurement accuracy can be improved.

  The determination device determines whether or not the lower thread remaining amount detected based on the lowest measured value has a necessary lower thread amount that enables one sewing of the sewing machine. In the discriminating apparatus, the surface height H when the necessary lower thread amount enabling one sewing is wound around the bobbin winding 35 is set as a threshold value. When the measured surface height falls below this threshold value, the notification means notifies, for example, by turning on a red lamp and sounding a buzzer. When the shortage of the lower thread is notified, the bobbin is replaced with a bobbin in which the lower thread is fully wound.

  Next, the second measurement will be described. The second measurement is started in synchronization with the output of the sewing machine start signal. By starting the measurement in synchronization with the output of the start signal, when the sewing is resumed when the operator changes or when a power failure occurs, the amount of necessary lower thread that enables at least one sewing is provided. Whether or not it remains on the bobbin can be confirmed when the sewing machine is started. As a result, the remaining amount of the lower thread can be carefully detected, and the occurrence of poor sewing can be more reliably prevented.

  FIG. 5 shows the posture of the outer hook 9 when the sewing machine is started up, where the sword tip 7 is at the upper end side position 60 and the first, second and third measurement openings 13, 16, 19 is in communication. In this state, in the same manner as described above, the irradiation laser beam 62 is irradiated from the irradiation unit 23 of the laser displacement meter 21a toward the outer peripheral surface 27 through the communication measurement opening 22, and is reflected by the outer peripheral surface 27. The reflected laser beam 65 is received by the light receiving unit 30 of the laser displacement meter 21 a through the communication measurement opening 22. Then, based on the principle of triangulation based on the light receiving position information of the light output from the light receiving portion 30, the surface height H (FIG. 6) of the wound yarn portion 26 is measured. The measurement is performed, for example, a plurality of times (for example, five times) per 1/100 second, and the lowest measured value among the measured values of the plurality of times is detected as the position of the outer peripheral surface 27 of the winding portion 26.

  At the time of starting the sewing machine, the lower thread 2 is often loosened on the outer peripheral surface 27 of the wound thread portion 26 by cutting the lower thread after completion of predetermined sewing. In the same manner as described above, air is blown to the outer peripheral surface 27 through the communication measurement opening 22. By this air blowing, it is easy to remove the slack portion 69 of the lower thread from the portion 27A facing the communication measurement opening 22 in the outer peripheral surface 27 in the same manner as described with reference to FIG. Therefore, even if the lower thread 2 wound around the bobbin 3 is slack, the minimum value can be measured without being affected by the slack of the thread as much as possible, and the outer peripheral surface 27 of the wound thread portion 26 can be measured. Accuracy can be improved.

  Then, the determination device determines whether the lower thread remaining amount detected based on the lowest measured value has a necessary lower thread amount that enables one sewing of the sewing machine. In the discriminating apparatus, the surface height H when the necessary lower thread amount enabling one sewing is wound around the bobbin winding 35 is set as a threshold value. When the measured surface height H falls below this threshold value, the notification means notifies, for example, by turning on a red lamp and sounding a buzzer. When the shortage of the lower thread amount of the bobbin 3 is notified, the bobbin 3 is replaced with a bobbin in which the lower thread is wound to the full capacity. When it is determined that the detected remaining amount of the lower thread has a necessary lower thread amount that enables one sewing of the sewing machine, sewing of the sewing machine is started.

  The present invention is by no means limited to those shown in the above-described embodiments, and it goes without saying that various design changes can be made within the scope of the claims. One example is as follows.

(1) When the first, second, and third measurement openings 13, 16, and 19 are provided, the rotation of the outer hook 9 is taken into consideration so that they communicate with each other and the communication measurement opening 22 is formed. It needs to be configurable. In addition, when the lower thread 2 wound around the bobbin 3 is slack, it is necessary to prevent the slack thread from jumping out of the communication measurement opening 22. Furthermore, the optical measuring instrument 21 as the laser displacement meter or the like can measure the position of the outer peripheral surface 27 of the bobbin portion 26 of the bobbin 3 a plurality of times in a state where the communication measurement opening 22 is formed. Cost.

  If this condition is satisfied, the first measurement opening 13 provided in the peripheral wall portion 12 of the bobbin case 5 does not need to be formed in a long hole shape in the circumferential direction of the peripheral wall portion 12, and the first It is not essential that the measurement opening 13 is provided close to the front surface portion 42 of the bobbin case 5. For example, the first measurement opening 13 may be provided at the central portion in the front-rear direction of the peripheral wall portion 12 of the bobbin case 5 or may be provided near the rear surface side. In addition, the first measurement opening 13 may be provided in a long hole shape that is long in the front-rear direction of the peripheral wall portion 12 (the length direction of the bobbin winding 35).

(2) As long as the optical measuring instrument 21 can measure the position of the outer peripheral surface 27 of the bobbin portion 26 of the bobbin 3 based on the principle of triangulation, in addition to the laser displacement meter described above, infrared rays, etc. It is also possible to use a measuring instrument that uses the above light.

  And the irradiation light irradiated from the irradiation part 23 of the said optical measuring device 21 may be an above described spot light, or a linear line light. When the line light of laser light is used as the line light, for example, a light having a length of about 2.2 mm and a width of about 60 microns can be used. When line light is used, the first measurement opening 13 is preferably formed in a long hole shape that is long in the front-rear direction of the peripheral wall portion 12 of the bobbin case 5.

(3) Since the second measurement is started in synchronization with the output of the start signal of the sewing machine, if the bobbin 3 is loosely attached to the bobbin case 5 (bobbin 3 is For example, when the height is lowered by about 0.2 mm, the threshold value is set to be smaller by, for example, this amount of play considering this backlash.

(4) In the present invention, the sewing machine hook 11 comprising the inner hook 6 and the outer hook 9 is not limited to the vertical full rotary hook described above, but is a vertical half rotary hook, a horizontal full rotary hook, a horizontal half turn. It may be a kettle. Further, the lower thread remaining amount detecting device 1 according to the present invention can be applied to the case where various kinds of sewing are performed by a sewing machine in addition to the case of sewing the airbag or the seat belt.

DESCRIPTION OF SYMBOLS 1 Bobbin thread remaining amount detection apparatus 2 Bobbin thread 3 Bobbin 5 Bobbin case 6 Inner hook 7 Blade tip 8 Sewing machine 9 Outer hook 10 Lower thread remaining amount detection means 11 Sewing hook 12 Peripheral wall part 13 First measurement opening 15 Peripheral wall part 16 2nd Measurement aperture 17 peripheral wall portion 19 third measurement aperture 21 optical measuring instrument 22 communication measurement aperture 23 irradiation portion 25 irradiation light 26 winding yarn portion 27 outer peripheral surface 29 reflected light 30 light receiving portion 31 air blow device 32 blowing nozzle 33 upper yarn 62 irradiation Laser beam 65 Reflected laser beam 69 Loose portion of lower thread 70 Surface 72 Adhesion prevention nozzle

Claims (8)

In a sewing machine comprising an inner hook that holds a bobbin case that accommodates a bobbin on which a bobbin thread is wound so as to be rotatable about its axis, and an outer hook that includes a sword tip and that can rotate the outer periphery of the inner hook. A bobbin thread remaining amount detecting device for detecting the remaining amount of bobbin thread wound around a bobbin by a bobbin thread remaining amount detecting means,
A first measurement opening is provided in the peripheral wall portion of the bobbin case so as to face the outer peripheral surface of the winding portion wound around the bobbin, and the peripheral wall portion of the inner hook that houses the bobbin case A second measurement opening that can communicate with the first measurement opening is provided, and the peripheral wall portion of the outer pot is interrupted. 1, a third measurement opening that can communicate with the second measurement opening;
The lower thread remaining amount detecting means is configured by using a triangulation optical measuring instrument, and the first, second and third measurement openings are connected to form a communication measurement opening. Irradiation light is irradiated from the irradiation section of the optical measuring instrument toward the outer peripheral surface of the bobbin winding portion through the communication measurement opening, and reflected light reflected by the outer peripheral surface is transmitted to the communication surface. Based on the principle of triangulation based on the light receiving position information of the light output from the light receiving portion, the light receiving portion of the optical measuring device receives light through the measurement aperture. The position is measured, and the measurement is performed a plurality of times, and the lowest measurement value of the measurement values of the plurality of times is detected as the position of the outer peripheral surface of the winding portion. ,
And a discriminating device for discriminating whether or not the remaining amount of bobbin thread detected based on the lowest measured value has a necessary bobbin thread amount that enables one sewing of the sewing machine,
In addition, air is blown through a portion of the outer peripheral surface of the bobbin wound portion facing the communication measurement opening through the communication measurement opening, and the slack portion of the lower thread generating the air on the outer peripheral surface lower thread remaining amount of the sewing machine, characterized in that the該弛viewed part, the irradiation light is to order the air blow device is provided so as away of from the opposing portions so as not hit the該弛viewed part against the Detection device. In a sewing machine comprising an inner hook that holds a bobbin case that accommodates a bobbin on which a bobbin thread is wound so as to be rotatable about its axis, and an outer hook that includes a sword tip and that can rotate the outer periphery of the inner hook. A bobbin thread remaining amount detecting device for detecting the remaining amount of bobbin thread wound around a bobbin by a bobbin thread remaining amount detecting means,
A first measurement opening is provided in the peripheral wall portion of the bobbin case so as to face the outer peripheral surface of the winding portion wound around the bobbin, and the peripheral wall portion of the inner hook that houses the bobbin case A second measurement opening that can communicate with the first measurement opening is provided, and the peripheral wall portion of the outer pot is interrupted. 1, a third measurement opening that can communicate with the second measurement opening;
When sewing is completed and a thread trimming signal is output, the first, second, and third measurement openings are communicated to form a communication measurement opening.
The lower thread remaining amount detecting means is configured by using a triangulation optical measuring instrument, and the first, second and third measurement openings are connected to form a communication measurement opening. Irradiation light is irradiated from the irradiation section of the optical measuring instrument toward the outer peripheral surface of the bobbin winding portion through the communication measurement opening, and reflected light reflected by the outer peripheral surface is transmitted to the communication surface. Based on the principle of triangulation based on the light receiving position information of the light output from the light receiving portion, the light receiving portion of the optical measuring device receives light through the measurement aperture. Measuring the position,
The measurement is started in synchronization with the output of the thread trimming signal in a state where the communication measurement opening is formed, and the measurement is performed after the thread trimming signal is output and the lower thread. Is performed a plurality of times in the time period until the cutting of the wire is started, and the lowest measured value among the measured values of the plurality of times is detected as the position of the outer circumferential surface of the wound portion. ,
And a discriminating device for discriminating whether or not the remaining amount of bobbin thread detected based on the lowest measured value has a necessary bobbin thread amount that enables one sewing of the sewing machine,
In addition, air is blown through a portion of the outer peripheral surface of the bobbin wound portion facing the communication measurement opening through the communication measurement opening, and the slack portion of the lower thread generating the air on the outer peripheral surface lower thread remaining amount of the sewing machine, characterized in that the該弛viewed part, the irradiation light is to order the air blow device is provided so as away of from the opposing portions so as not hit the該弛viewed part against the Detection device. In a sewing machine comprising an inner hook that holds a bobbin case that accommodates a bobbin on which a bobbin thread is wound so as to be rotatable about its axis, and an outer hook that includes a sword tip and that can rotate the outer periphery of the inner hook. A bobbin thread remaining amount detecting device for detecting the remaining amount of bobbin thread wound around a bobbin by a bobbin thread remaining amount detecting means,
A first measurement opening is provided in the peripheral wall portion of the bobbin case so as to face the outer peripheral surface of the winding portion wound around the bobbin, and the peripheral wall portion of the inner hook that houses the bobbin case A second measurement opening that can communicate with the first measurement opening is provided, and the peripheral wall portion of the outer pot is interrupted. 1, a third measurement opening that can communicate with the second measurement opening;
When the start signal of the sewing machine is output, the first, second and third measurement openings are communicated to form a communication measurement opening.
The lower thread remaining amount detecting means is configured by using a triangulation optical measuring instrument, and the first, second and third measurement openings are connected to form a communication measurement opening. Irradiation light is irradiated from the irradiation section of the optical measuring instrument toward the outer peripheral surface of the bobbin winding portion through the communication measurement opening, and reflected light reflected by the outer peripheral surface is transmitted to the communication surface. Based on the principle of triangulation based on the light receiving position information of the light output from the light receiving portion, the light receiving portion of the optical measuring device receives light through the measurement aperture. Measuring the position,
The measurement is started in synchronism with the output of the activation signal and is performed a plurality of times, and the lowest measured value among the measured values of the plurality of times is determined as the position of the outer peripheral surface of the winding portion. It is made to detect as
And a discriminating device for discriminating whether or not the remaining amount of bobbin thread detected based on the lowest measured value has a necessary bobbin thread amount that enables one sewing of the sewing machine,
In addition, air is blown through a portion of the outer peripheral surface of the bobbin wound portion facing the communication measurement opening through the communication measurement opening, and the slack portion of the lower thread generating the air on the outer peripheral surface lower thread remaining amount of the sewing machine, characterized in that the該弛viewed part, the irradiation light is to order the air blow device is provided so as away of from the opposing portions so as not hit the該弛viewed part against the Detection device. In a sewing machine comprising an inner hook that holds a bobbin case that accommodates a bobbin on which a bobbin thread is wound so as to be rotatable about its axis, and an outer hook that includes a sword tip and that can rotate the outer periphery of the inner hook. A bobbin thread remaining amount detecting device for detecting the remaining amount of bobbin thread wound around a bobbin by a bobbin thread remaining amount detecting means,
A first measurement opening is provided in the peripheral wall portion of the bobbin case so as to face the outer peripheral surface of the winding portion wound around the bobbin, and the peripheral wall portion of the inner hook that houses the bobbin case A second measurement opening that can communicate with the first measurement opening is provided, and the peripheral wall portion of the outer pot is interrupted. 1, a third measurement opening that can communicate with the second measurement opening;
When sewing is completed and a thread trimming signal is output, the first, second, and third measurement openings are communicated to form a communication measurement opening.
And when the start signal of the sewing machine is outputted, the first, second and third measurement openings are communicated to form a communication measurement opening.
The lower thread remaining amount detecting means is configured by using a triangulation optical measuring instrument, and the first, second and third measurement openings are connected to form a communication measurement opening. Irradiation light is irradiated from the irradiation section of the optical measuring instrument toward the outer peripheral surface of the bobbin winding portion through the communication measurement opening, and reflected light reflected by the outer peripheral surface is transmitted to the communication surface. Based on the principle of triangulation based on the light receiving position information of the light output from the light receiving portion, the light receiving portion of the optical measuring device receives light through the measurement aperture. Measuring the position,
The measurement is started in synchronization with the output of the thread trimming signal in a state where the communication measurement opening is formed, and the measurement is performed after the thread trimming signal is output and the lower thread. Is performed a plurality of times in the time period until the cutting of the wire is started, and the lowest measured value among the measured values of the plurality of times is detected as the position of the outer circumferential surface of the wound portion. ,
The measurement is started in synchronism with the output of the start signal and is performed a plurality of times, and the lowest measured value among the measured values of the plurality of times is determined on the outer peripheral surface of the winding portion. It is made to detect as a position,
And a discriminating device for discriminating whether or not the remaining amount of bobbin thread detected based on the lowest measured value has a necessary bobbin thread amount that enables one sewing of the sewing machine,
In addition, air is blown through a portion of the outer peripheral surface of the bobbin wound portion facing the communication measurement opening through the communication measurement opening, and the slack portion of the lower thread generating the air on the outer peripheral surface lower thread remaining amount of the sewing machine, characterized in that the該弛viewed part, the irradiation light is to order the air blow device is provided so as away of from the opposing portions so as not hit the該弛viewed part against the Detection device. A peripheral wall portion that is not covered by the outer hook of the inner hook when the thread trimming signal is output, and a peripheral wall that is not covered by the outer hook of the inner hook when the start signal is output in part, with the second measurement aperture is provided, the peripheral wall of the bobbin case, characterized in that the first measuring opening can through the measurement aperture and communicating the second is provided according Item 5. A lower thread remaining amount detection device for a sewing machine according to Item 4 . The sewing machine according to any one of claims 1 to 5 , wherein a spray nozzle for spraying air is provided on a cover surface of the irradiation unit and a cover surface of the light receiving unit of the optical measuring instrument. Lower thread remaining amount detection device. A spray nozzle is provided for spraying air onto the surface of the cover of the irradiation unit and the surface of the cover of the light receiving unit of the optical measuring device, and a part of the air supplied from the same air supply source is the air blow While the remaining air is supplied to the apparatus, the remaining air is supplied to the spray nozzle, and the supply of these airs is intermittently performed in accordance with the formation timing of the communication measurement opening. The bobbin thread remaining amount detecting device according to claim 1, 2, 3, 4, or 5 . The lower thread remaining amount detecting device according to any one of claims 1 to 7 , wherein the measurement is performed a plurality of times per 1/100 second.

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