JP6425512B2 - Sewing machine eye skipping and thread breakage detecting device - Google Patents

Description

  The present invention is a sewing machine that detects eye jump and thread breakage by detecting with a photoelectric sensor an upper thread passing through a hook to extend from a sewing machine needle that has passed through a cloth and to be scooped by a sword tip of the hook and pass a lower thread. And a yarn breakage detecting device.

  Sewing of the sewing machine is performed by forming a seam by winding the upper thread and the lower thread as required. More specifically, although the sewing needle with the upper thread penetrates the fabric and protrudes to the lower side of the fabric and then moves upward, the upper thread sags and loops when the sewing needle reaching the bottom dead center moves upward. Is formed. At the same time, the hook, which rotates in conjunction with the vertical movement of the sewing needle, scoops the upper thread that has become the loop at the point of the sword at a position where the sewing needle slightly rises above the bottom dead center. Then, the hook rotates and the balance rises at a position where the sword tip has passed a predetermined position, whereby the looped upper thread is removed from the hook tip of the kettle and pulled upward. As a result, the lower thread coming out of the bobbin case and reaching the fabric is entangled with the upper thread to form one seam.

Sewing is performed in this manner, but the hook tip of the hook does not go through the loop due to the relation between the up-down movement of the sewing machine needle and the timing of rotation of the hook, the tension of the thread, etc. There may be a case where the eye is not formed across the surface. In addition, even when the upper thread is broken, a situation may occur where no seam is formed.
In order to solve such problems, the method for detecting stitch skipping in the sewing machine described in Patent Document 1 is that the upper thread covered with the tip of the hook of the hook becomes a loop during one upward and downward movement of the sewing needle. In the sewing machine in which the front yarn portion of the upper yarn in the loop crosses the surface of the bobbin case housed in the hook, the presence or absence of the front yarn portion is reflected Contactlessly detected by a light sensitive photodetector. To that end, a photodetector is arranged (in an embodiment at an angle of about 45 degrees with respect to the axis of rotation of the kettle) to emit light towards the surface of the bobbin case. Further, in the invention described in Patent Document 1, it is preferable that the photoelectric detector be configured as a color difference photoelectric detector capable of discriminating the color of the yarn by comparison with the color of the surface of the bobbin case.

JP 2000-197786 A

However, as in the invention described in Patent Document 1, when detecting the passage of the upper thread by the reflection type photoelectric sensor which emits light toward the surface of the bobbin case, there are the following problems.
First, since light is emitted toward the surface of the bobbin case, the detection period of the upper thread by the photoelectric sensor is at a time when the phase is very limited with respect to the rotation cycle of the kettle, and the rotational speed of the kettle is high. The shorter the time, the higher the possibility that the upper thread can not be detected as passing without being detected.
In addition, it is difficult to apply the eye jump detection method described in Patent Document 1 to a sewing machine having a horizontal hook. Since the needle plate and the needle plate slide exist in the opposing range (upper range) of the surface of the bobbin case housed in the horizontal kettle, the photoelectric sensor is configured to emit light toward the surface of the bobbin case housed in the horizontal kettle Difficult to place.
Furthermore, since either the reflected light from the surface of the bobbin case or the reflected light from the passing upper thread is always received by the photoelectric sensor, it is necessary to determine the passage of the upper thread by comparing these reflected lights. In patent document 1, discrimination | determination by a color difference is mentioned, However, In order to discriminate | determine in high sensitivity, the need of a special photoelectric sensor not cheap general purpose things arises.

  Therefore, the present invention detects eye jump and thread breakage by detecting an upper thread passing through the hook with a photoelectric sensor, extending from a sewing needle that has passed through the fabric and being scooped by the tip of the hook and passing the lower thread. An object of the present invention is to make it easy to apply to a horizontal hook, to improve the determination accuracy of eye jump and thread breakage, and to be able to be implemented at low cost.

The invention according to claim 1 is an eye jump and a thread break by detecting, with a photoelectric sensor, an upper thread which passes from the sewing machine needle which has passed through the cloth and is passed by the hook to be caught by the hook tip of the hook and to pass the lower thread. In a sewing machine for detecting jumps and broken threads in a sewing machine,
The light path from the light emitting part to the light receiving part of the photoelectric sensor passes the passing range of the upper thread, and the end face in the rotational axis direction of the shuttle opposite to the lower shaft transmitting rotational power to the shuttle is viewed vertically It is provided to cross the end face ,
It is characterized in that the passage of the upper thread is determined based on the amount of light received by the light receiving section.

  The invention according to claim 2 is the device for detecting skipping and thread breakage of a sewing machine according to claim 1, when the hook is divided on the plane including the rotation axis and the central axis of the sewing needle. It is characterized in that the light emitting unit is installed on the side to which the sword tip made of a thread goes forward.

  The invention according to claim 3 is the device for detecting jumps and breaks in a sewing machine according to claim 1 or 2, wherein an optical axis of light emitted from the light emitting unit transmits rotational power to the hook. It is characterized by coinciding with the end face of the above-mentioned kettle opposite to the axis.

  The invention according to claim 4 is characterized in that, in the sewing machine according to any one of claims 1 to 3, the hook is a horizontal hook.

  According to a fifth aspect of the present invention, in the sewing machine according to the first or second aspect, the device for detecting jump and thread breakage of a sewing machine comprises a plurality of light receiving elements, the light receiving elements being offset in the horizontal direction and the vertical direction It is characterized by being arranged.

  The invention as set forth in claim 6 is characterized in that, in the sewing machine as claimed in claim 5, the plurality of light receiving elements respectively detect the amounts of light received.

According to the first aspect of the present invention, the optical path from the light emitting portion to the light receiving portion of the photoelectric sensor is provided to cross the hook in the direction perpendicular to the rotation axis of the pot while passing through the passing range of the upper thread. The moving direction of the upper thread moved by the sword tip of the kettle approximates the transverse direction of the light path, and the period in which the light path to the light receiving portion is interrupted by the upper thread is long. I can take a long time. Thereby, the determination accuracy of eye jump and thread breakage is improved. At the same time, it is also easy to apply the photoelectric sensor to the horizontal pot through the light path from the light emitting part to the light receiving part in the narrow gap between the upper end face of the horizontal pot and the needle plate and the like.
In addition, it is detected by the difference between the amount of light received when the light path to the light receiving part is blocked by the upper thread and when it is not blocked, so it is sufficient to apply inexpensive general-purpose light emitting elements and light receiving elements as photoelectric sensors. It is possible to achieve good discrimination accuracy.

When the upper thread passes through the kettle, the upper half of the hook section slips out of the kettle, so the behavior of the loop portion of the upper thread is unstable with respect to the section where the upper half thread is pulled to the tip of the sword. . When the light from a light emitting diode or the like has spread, the smaller the distance from the light emitting part of the photoelectric sensor to the object to be detected, the larger the shadow by the object to be detected, and the clear change in the amount of light received by the light receiving part Cheap.
According to the second aspect of the invention, in the section where the upper thread of the first half is drawn to the tip of the sword, light can be emitted from the light emitting portion close to the upper thread, and a change in the amount of received light can be detected stably and clearly. It is possible to improve the determination accuracy of popping and thread breakage.

When the light axis of the light emitted from the light emitting portion of the photoelectric sensor is separated outward from the end face of the pot, the shadow is projected onto the pot when the light is irradiated to the passing upper thread, so the light receiving portion However, if the light axis of the light emitted from the light-emitting portion of the photoelectric sensor intersects the hook, the upper thread passes. However, the light receiving portion may not be able to detect a change in the amount of light received due to the passage of the upper thread.
According to the invention of claim 3, since the optical axis of the light emitted from the light emitting portion coincides with the end face of the pot, the shadow of the passing upper thread is also projected onto the pot It is possible to detect changes in the amount of received light due to the passage of the upper thread sufficiently by the light receiving section without entering the shadow of the kettle, and it is possible to improve the determination accuracy of eye jump and thread breakage.

  According to the fourth aspect of the present invention, it is possible to detect an upper thread passing through the horizontal pot by means of a photoelectric sensor and to detect jump and thread breakage.

According to the fifth aspect of the present invention, by arranging the light receiving portions of the photoelectric sensor with the plurality of light receiving elements offset in the horizontal direction and the vertical direction, it is possible to configure the light receiving portion having a wide detection range at low cost. become.

  According to the sixth aspect of the invention, it is possible to finally determine the eyebrows and thread breakage based on the detection results of a plurality of light receiving elements, and thereby it is possible to improve the judgment accuracy of eyebrows and thread breakage. .

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view of the part centering on the horizontal hook of the sewing machine with which the eye-catching detection apparatus which concerns on one Embodiment of this invention was applied. It is a figure of the part centering on the horizontal hook of the sewing machine to which the eye jump etc. detection device concerning one embodiment of the present invention was applied, and it is the perspective view seen from the angle different from FIG. It is a block diagram of a control system of a sewing machine to which an eye-catching etc. detection device concerning one embodiment of the present invention is applied. It is a wave form diagram of the output signal of the photoelectric sensor contained in the eye-catching detection apparatus which concerns on one Embodiment of this invention. The encoder Z-phase signal is also described. It is a flowchart concerning eye jump detection processing operation by the eye jump detection apparatus according to an embodiment of the present invention. It is the top view (a) and perpendicular | vertical sectional view (b) which showed typically the light-emitting part of the hook of the sewing machine and photoelectric sensor which concern on one Embodiment of this invention. FIG. 6 is a vertical cross-sectional view schematically showing a hook of a sewing machine and a light emitting unit of a photoelectric sensor according to an embodiment of the present invention, showing another example of the arrangement of the light emitting unit. FIG. 6 is a vertical cross-sectional view schematically showing a hook of a sewing machine and a light emitting unit of a photoelectric sensor according to an embodiment of the present invention, showing another example of the arrangement of the light emitting unit. The schematic diagram (a) which showed arrangement | sequence of three light receiving elements which comprise the light receiving part of the photoelectric sensor which concerns on one Embodiment of this invention, the parallel circuit diagram (b) of the several light receiving element, and upper sensor area, lower It is a schematic diagram (c) which shows the combination of the side sensor area. It is the model (a) (b) (c) (d) which showed the various states of the upper thread which passes with respect to the kettle | hook with which the light-receiving part shown in FIG. 9 was put side by side. A schematic waveform diagram (a) showing the temporal change of the total value of the three light receiving elements when the upper thread passes in the state of FIG. 10 (a), when the upper thread passes in the state of FIG. 10 (b) A schematic waveform diagram (b) showing the temporal change of the total value of three light receiving elements, a schematic waveform showing the temporal change of the total value of three light receiving elements when the upper thread passes in the state of FIG. 10 (c) It is a typical waveform diagram (d) which shows the time change of the total value of three light receiving elements when upper thread passes in the state of figure (c) and FIG. 10 (d). A schematic waveform diagram (a1) showing a temporal change of a total value of upper two light receiving elements when an upper thread passes in a state of FIG. 10A shows a temporal change of a total value of lower two light receiving elements A schematic waveform diagram (a2), a schematic waveform diagram (b1) showing a temporal change of a total value of upper two light receiving elements when upper thread passes in a state of FIG. 10 (b) and two lower light receiving elements A schematic waveform diagram (b2) showing a temporal change of the sum of the two, and a schematic waveform diagram (c1) showing a temporal change of the sum of the upper two light receiving elements when the upper thread passes in the state of FIG. And a schematic waveform diagram (c2) showing the time change of the combined value of the lower two light receiving elements, and the time change of the combined value of the upper two light receiving elements when the upper thread passes in the state of FIG. They are a typical waveform diagram (d1) which shows these, and a typical waveform diagram (d2) which shows the time change of the sum total of two lower light receiving elements.

The eye jump and thread break detecting device (hereinafter referred to as "eye skipping detection device") according to the present invention will be described with reference to the drawings.
1 and 2 show perspective views of a portion centered on a horizontal hook of a sewing machine to which the eye jump detection system 10 according to an embodiment of the present invention is applied. A block diagram is shown in FIG.
As shown in FIG. 3, the eye jump detection apparatus 10 includes a photoelectric sensor 11 and a CPU substrate 12. The CPU board 12 is connected to the photoelectric sensor 11 and the sewing machine control board 20. The photoelectric sensor 11 includes a light emitting unit 13 and a drive unit 14 thereof, and a light receiving unit 15 and a signal amplification unit 16 thereof.

The horizontal hook 1, the needle hole 2, the light emitting part 13 and the light receiving part 15 are shown in FIG. 1 and FIG. The horizontal pot 1 has a tip 1a and rotates horizontally in the direction of arrow F.
After the needle of the sewing machine (not shown) falls into the needle hole 2 and reaches the bottom dead center, the loop of the upper thread generated when rising is scooped by the point 1a, and the horizontal hook 1 rotates in the arrow F direction. When the horizontal hook 1 further rotates and rotates about a half turn, the needle thread is pulled by the rising sewing needle and the upper thread slips out of the horizontal hook 1, and the loop of the upper thread passes through the horizontal hook 1. That is, at the time of sewing, the upper thread extends from the sewing needle which has passed through the cloth, is covered with the tip 1a of the horizontal hook 1 and passes above the horizontal hook 1 to pass the lower thread. The upper thread passing through the horizontal hook 1 is detected by the photoelectric sensor 11.

  The light path L1 from the light emitting unit 13 to the light receiving unit 15 of the photoelectric sensor 11 is provided to cross the horizontal hook 1 in the vertical direction with respect to the rotation axis A1 of the horizontal hook 1 while passing the passing range of the upper thread. . In the present embodiment, since the horizontal pot 1 is employed, the light path L1 traverses immediately above the upper end surface 1b of the horizontal pot 1. When both sides of the horizontal hook 1 are divided by a plane including the rotation axis A1 of the horizontal hook 1 and the central axis A2 of the sewing needle, the light emitting portion 13 is installed on the side F1 to which the sword tip 1a which shreds the upper thread 3 advances. ing. The light receiving unit 15 is disposed on the opposite side F2. When a mirror is installed at the position of the light receiving unit 15 in the drawing and light from the light emitting unit 13 is reflected to the F1 side, the light receiving unit 15 can be installed on the same side F1 as the light emitting unit 13.

The CPU substrate 12 functions as means for determining the passage of the upper thread 3 based on the amount of light received by the light receiving unit 15.
A phase signal of the upper axis (spindle) of the sewing machine is input to the sewing machine control board 20 from the encoder 21. The encoder A-phase signal 31 input from the sewing machine control board 20 to the CPU board 12 is a minimum unit signal, and outputs one pulse at 1 ° of the upper shaft rotation in this embodiment. The encoder Z-phase signal 32 input from the sewing machine control board 20 to the CPU board 12 is a pulse signal having one cycle of one rotation of the upper axis. The horizontal hook 1 with one rotation of the upper shaft rotates twice, and the sewing needle reciprocates once.

A drive control signal from the CPU substrate 12 is input to the drive unit 14 of the photoelectric sensor 11, and the light emitting unit 13 is driven to emit light. A photoelectric conversion signal corresponding to the amount of light received by the light receiving unit 15 is amplified by the signal amplification unit 16 to be an output signal 34 and input to the CPU substrate 12. The upper thread detection range is in advance in the phase range in which the upper thread 3 blocks the optical path L1 from the light emitting unit 13 to the light receiving unit 15 of the photoelectric sensor 11 when the sword tip 1a scoops the upper thread 3. It is set.
The CPU substrate 12 determines, based on the encoder A phase signal 31 and the encoder Z phase signal 32, whether or not the output signal 34 of the photoelectric sensor 11 has a change due to the passage of the upper thread 3 in the upper thread detection range. That is, when a change due to the passage of the upper thread 3 is recognized, it is determined that the upper thread 3 has passed normally, that is, there is no eye popping and thread breakage, and a change due to the passage of the upper thread 3 is observed. If the upper thread detection range ends without being judged, it is determined that there is an eye jump or a thread break, and an eye jump detection signal 33 is output to the sewing machine control board 20.
A part of the waveform of the output signal 34 of the photoelectric sensor 11 monitored by the external computer 30 connected to the CPU substrate 12 is shown in FIG.

Further, the eye jump detection processing will be described along the flowchart of FIG.
First, when the CPU board 12 starts the eye jump detection process, the CPU board 12 turns off the eye jump detection flag (step S1).
Then, the CPU substrate 12 A / D converts the output signal 34 of the photoelectric sensor 11 and acquires it as a photoelectric sensor value (step S2).
Next, the CPU substrate 12 calculates the upper axis angle based on the encoder A phase signal 31 and the encoder Z phase signal 32, and if the upper axis angle is in the upper thread detection range (YES in step S3) The flag is turned on (step S4). Before entering the upper thread detection range, step S3 becomes NO, step S8 becomes NO, and the process returns to step S2.
When the upper thread 3 blocks the light path L1 between the light emitting unit 13 and the light receiving unit 15 when the upper thread 3 passes through the horizontal hook 1, the amount of light entering the light receiving unit 15 changes. As shown in FIG. 4, the point 34 a at which the output signal 34 of the photoelectric sensor 11 is changing is caused by the fact that the upper yarn 3 blocks the light path L1. When such a change is observed, the CPU substrate 12 determines that the upper thread 3 is detected.
The CPU substrate 12 determines whether the upper thread 3 is detected from the photoelectric sensor value in the upper thread detection range (step S5), and when the upper thread 3 is detected (YES in step S5), the flyout detection flag is turned off. (Step S6). After the upper thread is detected, the upper axis angle loops the process in the upper thread detection range (YES in step S7), and when it passes the upper thread detection range, the process returns to step S2 (NO in step S7), and then the upper thread Until the detection range is entered, NO is made in step S3 and NO is made in step S8, and the process returns to step S2.
On the other hand, when the upper thread 3 is not detected in the upper thread detection range and passes the upper thread detection range as it is, the step with NO in step S5 while keeping the eye pop detection flag ON in step S4. It returns to S2, becomes NO by step S3, and a process transfers to step S8.
In step S8, it is determined whether the eye jump detection flag is ON / OFF, and if it is ON, it is determined that there is an eye jump or thread breakage, and an eye jump detection signal 33 is output to the sewing machine control board 20 in step S9.
When the sewing machine control board 20 receives the eye jump detection signal 33, the sewing machine control board 20 performs stop control of the sewing operation and notification control for notifying the user of the detection of eye jump etc. via the display device.

Further, the arrangement of the light emitting unit 13 will be described with reference to FIGS. 6 to 8.
When a light emitting element such as a light emitting diode is applied to the light emitting unit 13, the irradiation range 40 expands in a conical shape in accordance with the distance from the light emitting unit 13 as shown in FIG. 6 (b) and FIG. 7 and FIG.
As shown in FIG. 6B, when the light axis AL of the light emitting unit 13 is perpendicular to the rotation axis A1 of the horizontal pot 1 and the light axis AL is above the upper end face 1b of the horizontal pot 1, light If the upper thread 3 exists below the axis AL, the shadow of the upper thread 3 overlaps the shadowed portion 41 of the horizontal hook 1 and the upper thread 3 passes even if the light receiver 15 is installed on the F2 side of the horizontal hook 1 May not be detected.
Similarly, when the optical axis AL is below the upper end surface 1b of the horizontal hook 1 (when the optical axis AL intersects the hook 1), the shadow of the horizontal hook 1 and the shadow portion of the upper thread 3 may overlap.
In order to detect the yarn efficiently, the optical axis AL perpendicular to the rotation axis A1 of the horizontal kettle 1 is made to coincide with the upper end face 1b of the horizontal kettle 1 as shown in FIG. The light receiving unit 15 is installed in a range where the shadow 42 of the upper thread is projected so as to be separately projected from the shadowed portion 41 of the kettle 1. The arrangement of the optical path L1 according to the above-described configuration shown and described with reference to FIGS. 1 to 5 is adopted.
In the case of an optical system in which the irradiation range spreads in a conical shape in this way, as shown in FIG. 8, the optical axis AL is viewed from the upper end face 1b of the horizontal pot 1 even when the optical axis AL is not aligned with the upper end face 1b of the horizontal pot 1. By forming an optical path provided so as to cross the horizontal hook 1 in a direction perpendicular to the rotation axis A1, it is sufficient if this is an effective optical path for detecting the passage of the upper thread 3. That is, the optical axis AL may not be the shortest optical path from the light emitting unit 13 to the light receiving unit 15.
Further, in the horizontal kettle 1, a lower shaft (not shown) for transmitting rotational power to the horizontal kettle 1 is installed on the lower side, so the upper end surface 1b is an end surface of the horizontal kettle 1 opposite to the lower shaft. . Also in the case of the vertical pot, the optical axis AL is set to the end face opposite to the lower axis.

The optical path L1 shown in FIGS. 1 and 2 is also shown in FIG. 6 (a). A straight line perpendicular to the straight line connecting the rotation axis A1 and the central axis A2 of the sewing needle on the horizontal plane of FIG. 6A and passing through the rotation axis A1 is taken as a reference light path L0. An optical path L1 from the light emitting unit 13 to the light receiving unit 15 of the photoelectric sensor 11 is located on the opposite side of the central axis A2 of the sewing needle with the reference optical path L0 as a boundary. Thus, even if the optical path is installed at a position away from the central axis A2 of the sewing needle with reference to the reference optical path L0, sufficient change of the output signal 34 can be obtained as shown in FIG. Can be determined.
However, in order to further increase the determination accuracy, it is preferable that the light emitting portion 13 be as close as possible to the upper thread 3 on the F1 side where the behavior of the upper thread 3 is stabilized. For that purpose, as shown in FIG. 6A, the light path L2 is parallel to the reference light path L0 and on the side closer to the central axis A2 of the sewing needle with respect to the reference light path L0. By installing the light emitting portion 13 as close as possible to the upper thread 3 in the range of more than 0 ° and less than 90 ° by adopting the light path L3 etc. which can be set in the range of more than 0 ° and less than 90 °. Is preferred.
As shown in FIG. 6A, on the F1 side described above, the rotational axis A1 is the center (observation point), the position of the central axis A2 of the sewing needle is 0 °, and the downstream side in the rotational direction F of the hook A section (section F1) corresponding to an azimuth of 0 ° to 180 ° corresponds to Further, a section (section F2) in an azimuth of 180 ° to 360 ° corresponds to the F2 side.

  In addition, as a light emitting element applied to the light emission part 13, a laser diode other than a light emitting diode is mentioned.

Further, the arrangement of the light receiving unit 15 will be described with reference to FIGS. 9 to 10.
Usually, a semiconductor element used as such a light receiving element is used for measuring the luminance of widely spread light, so the light receiving area is as small as about 0.5 mm × 0.5 mm. In addition, since the number of semiconductor elements that can be cut out from one semiconductor wafer increases as the area of the semiconductor elements decreases, the cost per sheet decreases as the area of the semiconductor elements decreases.
However, the semiconductor element used in the light receiving unit 15 used in the present invention is 1 mm or more in the vertical direction because of the position of the upper thread 3 passing above the horizontal kettle 1 and the arrangement of the light emitting unit 13 as a light source. A semiconductor device with a width of
Moreover, since the upper thread 3 passes above the horizontal hook 1 in the horizontal direction, the shadow 42 of the upper thread 3 is also projected in the horizontal direction. Therefore, if the semiconductor element is widely present in the horizontal direction, the detection area for detecting the shadow 42 of the projected upper thread 3 is increased.
In order to increase the detection area, it is conceivable to arrange the semiconductor elements in a matrix, but since the semiconductor elements have a case where the case is substantially outside the sensor portion, a wasteful space is generated.
Therefore, by arranging the semiconductor elements in the horizontal direction as the light receiving unit 15 and offsetting the semiconductor elements in the vertical direction, the range for detecting the shadow 42 of the upper thread 3 projected in the horizontal direction is expanded. The detection sensitivity of the shadow 42 of the upper thread 3 can be improved while using a small semiconductor element. For example, as shown in FIG. 9A, the detection range can be expanded by arranging the three semiconductor elements 15a, 15b, and 15c as the light receiving unit 15 with offset in the vertical direction. As shown in FIG. 9A, the three semiconductor elements 15a, 15b, 15c are mounted on the circuit board 15K with being offset in the horizontal direction and the vertical direction. Such offset is based on the condition that the actual detection area (light receiving surface) of the semiconductor element is offset.
Further, as shown in FIG. 9B, for example, the semiconductor elements 15a, 15b, and 15c are connected in parallel in a plurality of semiconductor elements, and the light reception amounts detected by the respective semiconductor elements are added together. Good.

Further, as a method of improving the detection accuracy of the eye jump etc. of the light receiving portion 15 shown in FIGS. 9A and 9B, the semiconductor elements 15a and 15b among the three semiconductor elements as shown in FIG. 9C. Is divided into the upper sensor area 15m and the semiconductor elements 15b and 15c into the lower sensor area 15n. More specifically, the light reception amount detected by each of the semiconductor elements 15a and 15b is added as a total value of the upper sensor area 15m, and the light reception amount detected by each of the semiconductor elements 15b and 15c as a total value for the lower sensor area 15n is totaled Then, the eye jump detection etc. is judged. Then, the sewing machine control board 20 determines that the sewing machine control board 20 has an eye jump only when it is determined that the eye jumping detection is detected in both the upper sensor area 15 m and the lower sensor area 15 n.
Normally, the upper thread 3 passes along the upper end surface 1b of the horizontal hook 1, but when sewing the step portion where the material to be sewn is overlapped and partially thickened, or when the sewing pitch is changed, When the yarn 3 becomes too faint and the upper yarn 3 passes through the upper end surface 1b of the kettle 1, the upper yarn 3 may run wild, and may be inclined or float. In such a case, in the method of adding and detecting the three semiconductor elements 15a, 15b and 15c, the change in the amount of light received due to the shadow 42 of the upper thread 3 becomes small, and the photoelectric sensor 11 detects the upper thread 3. There is also a possibility that false detection may be made as jumping eyes or thread breakage.
10 (a) shows a state in which the upper thread 3 is along the upper end surface 1b of the hook 1, FIG. 10 (b) shows a state in which the upper thread 3 floats horizontally above the hook 1, FIG. The upper yarn 3 is inclined, the semiconductor element 15a is detected as 3/4 open, the semiconductor element 15b is fully closed, and the semiconductor element 15c is detected as 1/2 open. In FIG. The element 15a is fully open, the semiconductor element 15b is 3/4 open, and the semiconductor element 15c is fully closed. The output value is 1 in the fully closed state in which the shadow of the upper thread 3 completely covers the actual detection area (light receiving surface) of the semiconductor element, and in the fully open state where the shadow does not cover the actual detection area (light receiving surface) of the semiconductor element at all The value is 0.
11 (a) to 11 (d) are output values in the method of summing the outputs of the semiconductor elements 15a, 15b and 15c, and FIGS. 12 (a1) to 12 (d2) to (d2) are semiconductor elements 15a. , 15b are divided into the upper sensor area 15m and the semiconductor elements 15b, 15c from the lower sensor area 15n, and the output values in the case of adding the output values for each area are shown. FIGS. 11 (a) to (d) and FIGS. 12 (a1) (a2) to (d1) (d2) correspond to the state of the upper thread 3 in FIGS. 10 (a) to (d), respectively. 12 (a1), (b1), (c1), and (d1) show the output value of the upper sensor area 15m. 12 (a2), (b2), (c2), and (d2) show output values of the lower sensor area 15n.
In the case of the method of summing the outputs of the semiconductor elements 15a, 15b and 15c, the output value of FIG. 11 (a) corresponding to the state of FIG. 10 (a) and FIG. 11 (b) corresponding to the state of FIG. In the output value of FIG. 11 (c) corresponding to the state of FIG. 10 (c), the sum of the outputs of the semiconductor elements 15a, 15b and 15c does not exceed the threshold TH and thus the upper thread 3 Detection of the shadow 42 of However, in the output value of FIG. 11 (d) corresponding to the state of FIG. 10 (d), the area of the shadow 42 of the upper thread 3 related to the actual detection area (light receiving surface) becomes insufficient. Since the total value of each output of 15c exceeds the threshold value TH, the upper thread 3 can not be detected despite the upper thread 3 being crossed, and erroneous detection of eye jump or thread breakage will occur.
On the other hand, in the case of the method of dividing the semiconductor elements 15a and 15b into the upper sensor area 15m and the semiconductor elements 15b and 15c from the lower sensor area 15n and summing the output values for each area, FIGS. As shown in d1) (d2), the upper thread 3 can be detected in any of the states shown in FIGS. 10 (a) to 10 (d). In the state of FIG. 10D, the sum of the semiconductor elements 15b and 15c in the lower sensor area 15n exceeds the threshold TH as shown in FIG. 12D2, but the upper sensor as shown in FIG. 12D1. Since the total value of the semiconductor elements 15a and 15b in the area 15m does not exceed the threshold value TH, it can be determined that the sewing machine control board 20 has an upper thread.
Therefore, the detection result can be calculated independently in each sensor area, and the presence of the upper thread 3 in any of the sensor areas can be detected. The unit 15 can detect a change in the amount of received light.
As described above, when a plurality of light receiving elements are offset and arranged, upper thread detection is performed in a plurality of areas having different positions, and when upper thread detection is possible in at least one of the areas, popping and thread breakage occur. If the upper thread can not be detected in any area, it is finally possible to discriminate between popping and thread breakage if there is jump or thread breakage in any area. Accuracy can be improved.

According to the above-described eye-popping detection apparatus of the present embodiment, the light path L1 from the light emitting unit 13 to the light receiving unit 15 of the photoelectric sensor 11 passes through the passing range of the upper thread 3 with respect to the rotation axis A1 of the hook 1 Since it is provided to cross the hook 1 in the vertical direction, the moving direction of the upper thread 3 moving by being trapped by the tip 1a of the hook 1 approximates the transverse direction of the light path L1, and the light path L1 to the light receiving unit 15 is The period intercepted by the upper thread 3 becomes long, and the detection period of the upper thread 3 by the photoelectric sensor 11 can be extended. Thereby, the determination accuracy of eye jump and thread breakage is improved. At the same time, it is easy to apply the photoelectric sensor 11 to the horizontal pot 1 through the light path L1 from the light emitting part 13 to the light receiving part 15 in a narrow gap between the upper end surface 1b of the horizontal pot 1 and the needle plate and the like.
Moreover, since it detects by the difference of the light reception amount with the time when the optical path L1 to the light reception part 15 is interrupted | blocked by the upper thread | yarn 3, and when not interrupted, the cheap general purpose light emitting element and light receiving element are used as the photoelectric sensor 11 It can be applied to achieve sufficient discrimination accuracy.

In the latter half section F2 of the hook rotation when the upper thread 3 passes the hook 1, the upper thread 3 slips out of the hook 1, so that the upper thread 3 of the first half 3 is drawn with respect to the section F1 The behavior of the loop part is unstable. When the light from the light emitting diode or the like is spread, the light from the light receiving unit 15 becomes larger as the distance from the light emitting unit 13 of the photoelectric sensor 11 to the detection target (upper thread 3) decreases. The change in quantity is clear and easy to detect.
According to the eye jump detection apparatus of the present embodiment, light is emitted from the light emitting portion 13 close to the upper thread 3 in the first half section F1 where the upper thread 3 is drawn to the tip 1a, and the amount of received light is stably and clearly A change can be detected, and the determination accuracy of eye jump and thread breakage can be improved.

When the optical axis AL of the light emitted from the light emitting portion 13 of the photoelectric sensor 11 is separated upward from the upper end surface 1b of the kettle 1 (the state of FIG. 6B), the passing upper yarn 3 is irradiated with light In this case, since the shadow is projected onto the hook 1, there is a possibility that the light receiving unit 15 can not sufficiently detect a change in the amount of light received due to the passage of the upper thread 3. When the optical axis AL of the light emitted from the light emitting portion 13 of the photoelectric sensor 11 intersects the hook below the upper end surface 1 b, the passing upper thread 3 enters the shadow of the hook 1 and the light receiving portion 15 There is a risk that the change in the amount of light received due to the passage of the upper thread 3 can not be detected sufficiently.
Since the optical axis AL of the light emitted from the light emitting unit 13 coincides with the upper end surface 1 b of the hook 1 according to the eye-jumping detection apparatus of the embodiment shown in FIG. 7, the shadow of the passing upper thread 3 Is projected onto the kettle, and the passing upper thread 3 does not enter the shadow of the pot 1, and the light receiving unit 15 can sufficiently detect the change in the amount of light received due to the passing of the upper thread 3, The determination accuracy of thread breakage can be improved.

Further, according to the eye-popping detection device of the present embodiment, the upper thread 3 passing through the horizontal hook 1 can be detected by the photoelectric sensor 11 to detect popping and thread breakage.
In the above embodiment, the configuration is shown in which the sewing needle and the horizontal hook are one set, but in the two-needle lock stitch sewing machine provided with two sets of the sewing needle and the horizontal hook, the eye jump etc. detection device of the present invention It is possible to apply and implement to each horizontal pot. In that case, if notification control is performed to notify which hook the eye-catching or the like has been detected, the spreading work can be made efficient.
Further, in the above embodiment, the configuration using the horizontal pot has been described, but in the eye-catching detection device of this embodiment, the light path from the light emitting unit 13 to the light receiving unit 15 of the photoelectric sensor 11 is the side provided with a sword tip The upper end surface in the direction of the rotation axis A1 may be viewed vertically and provided so as to cross the same end surface. Therefore, the present invention is also applicable to a sewing machine using a vertical hook.

DESCRIPTION OF SYMBOLS 1 Horizontal pot 1a Tip 1b Upper end face 2 Needle hole 3 Upper thread 10 Jumping detection device 11 Photoelectric sensor 12 CPU board 13 of Jumping detection device Light emitting unit 15 Light receiving unit 20 Sewing control board 21 Encoder A1 Rotation axis A2 Sewing needle Central axis AL Optical axis L0 Reference optical path L1 Optical path L2 Optical path L3 Optical path

Claims (6)

The stitch of the sewing machine which detects eye skipping and thread breakage by detecting an upper thread passing through the hook with a photoelectric sensor to extend from the sewing needle that has passed through the fabric and to be caught by the hook tip of the hook and pass the hook. In the yarn breakage detecting device,
The light path from the light emitting part to the light receiving part of the photoelectric sensor passes the passing range of the upper thread, and the end face in the rotational axis direction of the shuttle opposite to the lower shaft transmitting rotational power to the shuttle is viewed vertically It is provided to cross the end face ,
An apparatus for detecting jumps and breaks in threads of a sewing machine, which determines the passage of upper threads based on the amount of light received by the light receiving unit.   When both sides of the hook are divided by a plane including the rotation axis and the central axis of the sewing needle, the light emitting unit is installed on the side to which the sword tip with the upper thread advances. An apparatus for detecting skipping and thread breakage in a sewing machine according to Item 1.   The optical axis of the light emitted from the light emitting unit coincides with the end face of the kettle opposite to the lower shaft that transmits rotational power to the kettle. Sewing machine eye skipping and thread breakage detecting device.   4. The apparatus according to claim 1, wherein said hook is a horizontal hook. The sewing machine according to claim 1 or 2, wherein the light receiving portion is configured of a plurality of light receiving elements, and the light receiving elements are arranged to be offset in the horizontal direction and the vertical direction. Thread breakage detection device. 6. The apparatus according to claim 5, wherein each of the plurality of light receiving elements detects an amount of light received.

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