JPH0956950A - Bobbin thread residual quantity detecting device of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the residual quantity of a bobbin thread even during the operation of a sewing machine by controlling the operation of detecting the residual quantity of a bobbin thread according to the results of determining the rotating speed of a spindle and the turning angle range of a shuttle, in a detecting device in which a detecting rod is advanced into the shuttle through an opening of a rotating hook to detect the residual quantity of the bobbin thread. SOLUTION: In a control device 38 of a sewing machine, it is determined by a spindle rotating speed determining part 38C that the rotating speed of a spindle for moving up and down a needle is so low as to detect the residual quantity of a bobbin thread. Further it is determined by an opening position determining part 38A that a shuttle 34 rotated, interlocking with the spindle is in such a turning angle range as to introduce a detecting rod 31 through an opening by a driving device 32. According to the determination results, the driving device 32 is driven to detect the residual quantity of a bobbin thread through the detecting rod 31 by a bobbin thread residual quantity detecting tool 36. That is, an oscillatory wave detected by an oscillatory wave detecting element fitted to the outside of a yoke is discriminated by two kinds of comparators different in reference voltage to detect the bobbin thread.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bobbin thread remaining amount detecting device for a sewing machine, and more particularly, to a bobbin wound on a bobbin before the bobbin thread is exhausted. The present invention relates to a lower thread remaining amount detecting device for a sewing machine which is effective for re-sewing sewn products and preventing defective products.

[0002]

2. Description of the Related Art In a sewing machine, a bobbin wound with a bobbin thread is accommodated in a bobbin case, and this bobbin case is attached to a hook under the needle bar of the sewing machine. I can't see it with my eyes. Therefore, a device has been developed and is used that can detect when the lower thread of the sewing machine has run out before the lower thread of the sewing machine runs out.
One of them is disclosed, for example, in Japanese Utility Model Laid-Open No. 63-136591.

In the bobbin thread remaining amount detecting device disclosed in this publication, when the sewing machine which has completed sewing is stopped at a fixed position, a driving means such as a rotary solenoid is actuated to move the detecting rod to move its tip. The bobbin thread is detected by bringing the bobbin wound around the bobbin in the shuttle into contact with the outer peripheral portion of the bobbin thread and then reciprocating to return to the original position. That is, if the moving distance when the detection rod is moved forward is small, the remaining amount of the bobbin thread is large, and the moving distance gradually increases, and when it reaches the limit, the forward movement attached to the predetermined position is advanced. The magnetic sensor for detection operates to generate a bobbin thread consumption detection signal to notify the operator of the necessity of bobbin thread supplement.

As described above, in the conventional bobbin thread detection, the outer hook of the outer hook, which rotates in a state where the sewing machine is stopped at a fixed position, that is, in association with the rotation of the main shaft, has a fixed positional relationship with the detection device. It is stopped at that point, and in that state, the detection rod is inserted through the opening.

[0005]

However, conventionally, a plurality of sets of strip-shaped cloths have been sewn continuously without performing a thread cutting operation in the middle. In this case, the first set of cloths is sewn. When the sewing is finished, the next cloth is supplied without stopping the sewing machine, and the sewing operation is continued. Therefore, there is a problem that the lower thread may be lost during the sewing.

The present invention has been made to solve the above-mentioned conventional problems, and a lower thread residual amount of a sewing machine capable of detecting a lower thread residual amount by introducing a detection rod into the hook even when the sewing machine is operating. An object is to provide a quantity detection device.

[0007]

According to a first aspect of the present invention, a remaining amount of lower thread is advanced by advancing a detection rod from an opening of an outer hook into a hook containing a bobbin wound with a lower thread of a sewing machine. In the bobbin thread remaining amount detecting device for the sewing machine that detects the lower bobbin thread remaining amount, the linear actuator that is arranged at a predetermined position with respect to the shuttle and that moves the detection rod forward and backward and the rotation speed of the main shaft that moves the needle up and down The first determining means for determining that the speed is in a detectable state, and the shuttle rotating in conjunction with the rotation of the main shaft are in a rotation angle range in which the detection rod can be advanced by the linear actuator from the opening of the outer shuttle. Second determining means for determining
Control means for driving the linear actuator to control the bobbin thread remaining amount detecting operation when the determination result by the determination means and the determination result by the second determination means are satisfied at the same time;
The above-mentioned problem has been solved by adopting a configuration including:

According to a second aspect of the present invention, a lower part of a sewing machine for detecting a remaining amount of lower thread by advancing a detection rod from an opening of an outer hook into a hook containing a bobbin wound with a lower thread of the sewing machine. In the yarn remaining amount detecting device, it is arranged at a predetermined position with respect to the shuttle,
A linear actuator that moves the detection rod forward and backward, a first determination unit that determines that the rotational speed of the main shaft that moves the needle up and down is in a speed state in which the remaining amount of bobbin thread can be detected, and rotation that is interlocked with the rotation of the main shaft. Second determining means for determining that the rotary hook is within a rotation angle range in which the detection rod can be advanced by the linear actuator from the opening of the outer hook, the determination result by the first determining means, and the determination result by the second determining means. When both conditions are satisfied at the same time, the linear actuator is driven to control the control means for detecting the bobbin thread remaining amount and the linear actuator is driven forward, and the detection rod fixed to the movable part is moved forward into the shuttle. And a means for detecting vibration waves generated when there is a specified amount of bobbin thread and when there is no specified quantity of bobbin thread, and the control means drives the linear actuator forward. When any one of the vibration wave is detected when, by which to perform the control to reverse drive the linear actuator, is obtained by solving the above problems as well.

According to a third aspect of the present invention, the lower part of the sewing machine for detecting the remaining amount of the lower thread by advancing the detection rod from the opening part of the outer hook into the shuttle containing the bobbin wound with the lower thread of the sewing machine. In the yarn remaining amount detecting device, a detection rod driving means for moving the detection rod forward and backward, a means for detecting that the opening of the rotating outer hook is in a position where the detection rod can be moved forward, and the detection rod Means for detecting that the tip of the bobbin is in contact with the outer periphery of the bobbin thread wound around the bobbin when it is advanced inward, and the outer hook is in a position where the detection rod can be moved forward in the hook. At this time, the detection rod driving means advances the detection rod, and when it is detected that the tip of the detection rod comes into contact with the outer circumference of the bobbin thread, the detection operation of retracting the detection rod is executed. It is a solution to the problem.

According to a fourth aspect of the present invention, a lower part of a sewing machine for detecting a remaining amount of lower thread by advancing a detection rod from an opening of an outer hook into a hook containing a bobbin wound with a lower thread of the sewing machine. In the yarn remaining amount detecting device, a detection rod driving means for moving the detection rod forward and backward, a means for detecting that the opening of the rotating outer hook is in a position where the detection rod can be moved forward, and the detection rod A means for detecting that the tip of the bobbin is in contact with the outer periphery of the bobbin thread wound around the bobbin, or the movable part that moves together with the detection rod is in contact with the stopper part when it is advanced inward. When the outer hook is in a position where the detection rod can be advanced inside the hook,
The detection rod driving means advances the detection rod, and when it is detected that the tip of the detection rod is brought into contact with the outer circumference of the bobbin thread or the movable portion is brought into contact with the stopper portion, the detection operation of retracting the detection rod is executed. By doing so, the above problems are similarly solved.

That is, according to the first aspect of the invention, the first determining means determines that the rotational speed state is such that the forward and backward movements of the detection rod can be reliably performed, and the rotating hook is The second judging means judges that the rotation angle is within a range in which the detection rod can be advanced into the shuttle, that is, the opening portion of the shuttle is within the advance position of the detection rod, and the first determination means is used. Since the detection operation is performed only when the determination results of the second determination means are satisfied at the same time, the lower thread remaining amount can be detected safely and reliably without stopping the sewing machine. .

In order to detect the bobbin thread without stopping the sewing machine, it is of course necessary to accurately grasp the timing at which the detection rod can be introduced into the shuttle, and the detection rod is moved forward and backward in the shuttle. It is preferable to execute the detection operation at a high speed that does not hinder the sewing operation. In the present invention, since the detection rod is moved back and forth by the linear actuator, the operation only has to move forward and backward the movable part to which one end of the detection rod is fixed. Therefore, a complicated structure such as a crank mechanism is used. Is unnecessary, the actuator itself can be made small, and the movable part including the detection rod can be made small and lightweight, for example, 2 g or less, so that high-speed detection operation can be performed.

That is, the conventional bobbin thread remaining amount detecting device of the sewing machine disclosed in Japanese Utility Model Laid-Open No. 63-136591 uses a rotary solenoid or a plunger magnet and has a link mechanism for amplifying the operation amount. Since it is used, since the mass of the movable part is large, it takes a long time to move to the return operation after the detection rod is moved forward to perform the detection operation.As a result, the bobbin thread is pressed down by the detection rod. It is difficult to detect the remaining amount of the bobbin thread during the sewing operation in which the rotary hook is rotating, because the sewing time becomes long and the sewing operation is likely to be obstructed. No problem.

Further, in the above-mentioned conventional bobbin thread remaining amount detecting device, the magnetic sensor for detecting the forward movement is adapted to operate only when the bobbin thread is low, so that when the bobbin thread remaining amount is large, Even if the detection rod comes into contact with the thread, it is not detected. Therefore, in this case as well, there is a problem in that the detection thread presses the bobbin thread for a long time. In order to eliminate this, it is conceivable to dispose a magnetoresistive element so that the position of the detection rod can be continuously detected, but in this case as well, the resistance value of the magnetoresistive element of the resistance value It is necessary to monitor the change and determine that the detection rod has come into contact with the bobbin thread because the change is not within a predetermined time. Therefore, time is required for that, and high-speed operation is difficult after all.

According to a second aspect of the present invention, in the bobbin thread remaining amount detecting device similar to the first aspect, the actuator is driven forward, and the detection rod fixed to the movable portion is moved forward into the shuttle. Vibrations that occur when there is a specified amount of bobbin thread and when there is no specified amount of bobbin thread are detected, and when any of the above vibrations is detected when the actuator is driven forward, the actuator is immediately driven backward. I made it possible to move the detection rod forward,
Since the detection rod can be quickly retracted while being introduced into the shuttle to detect the presence or absence of the specified remaining amount of bobbin thread, the detection operation by the linear actuator can be executed reliably and at high speed.

According to the third aspect of the invention, it is detected that the opening of the rotating outer pot is in a position where the detection rod can be advanced, and the opening is in the position where it can be advanced. At this time, the detection rod can be moved back into the shuttle, and when it is detected that the tip of the detection rod has come into contact with the outer circumference of the bobbin thread wound around the bobbin, the detection rod can be moved backward. Even when the sewing machine is performing a sewing operation, it is possible to reliably detect the lower thread remaining amount based on the amount of advancement of the detection rod.

Further, in the invention of claim 4, similarly, the detection rod can be moved forward into the shuttle while the outer shuttle is rotating, and the presence or absence of the specified amount of the lower thread remaining amount is detected by the difference in vibration generated at that time. In addition, the detection rod is retracted when the vibration sound is detected, and thus the remaining amount of the bobbin thread can be similarly detected during the sewing operation.

According to a fifth aspect of the present invention, in the bobbin thread remaining amount detecting device according to the third or fourth aspect, the rotational speed of the sewing machine spindle is
In the case where the detection operation is executed when the rotation speed of the sewing machine spindle is determined to be in the above speed range Since the operation can be performed at a rotational speed at which the detection operation can be reliably performed according to the performance of the detection rod driving means, the lower thread remaining amount can be detected safely and accurately.

In addition, as in claim 6, claim 1, 2, 3
Alternatively, in the bobbin thread remaining amount detecting device of 4, when the bobbin is accommodated in the bobbin case, the detecting operation is executed when the opening of the bobbin case and the opening of the outer hook are aligned with each other. When the bobbin case is used, the bobbin thread remaining amount can be reliably detected during operation even with a normal sewing machine using a bobbin case.

In addition, as in claim 7, claim 1, 2, 3
Alternatively, in the bobbin thread remaining amount detection device of 4, when the timing for driving the detection rod forward is determined based on the timing signal corresponding to the rotation angle of the sewing machine spindle, the rotation angle of the spindle is For example, it is possible to accurately determine whether or not the opening of the outer hook is in a positional relationship capable of advancing the detection rod from the detected position by the rotary encoder, and thus the lower bobbin thread remaining amount can be reliably detected even during operation.

In addition, as in claim 8, claim 1, 2, 3
Alternatively, when the lower thread remaining amount detecting device 4 is equipped with a detection level display means for displaying the degree of the detected lower thread remaining amount, the operator can easily grasp the lower thread remaining amount.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

First, in describing the first embodiment of the present invention, a small size and a light weight which enables the operation of detecting the remaining amount of the lower thread during the operation of the sewing machine, a high speed operation is possible, and the lower thread is damaged. A detailed description will be given of a lower thread remaining amount detecting device including a linear actuator that is capable of accurately detecting the remaining amount as a hardware body. The applicant has already proposed a bobbin thread remaining amount detecting device using this linear actuator as a hardware body in Japanese Patent Application No. 6-167068.

FIGS. 1A, 1B and 1C are a plan view, a BB sectional view and a front view of the lower thread remaining amount detecting device (linear actuator), respectively. Further, FIG. 2 is a perspective view showing the detection device partially broken away. In the figure,
Reference numeral 1 is a detection rod bearing, 2A and 2B are permanent magnets that give a substantially uniform magnetic field within a span in which a coil 5B described later can move, and 3A and 3B are inside each of the permanent magnets 2A and 2B. Spaces 4 are permanent magnets 2A, 2B
And the permanent magnets 2A and 2B both have the same magnetic pole face toward the iron core 4.

Reference numeral 5 is a coil assembly that can slide freely on the iron core 4, and this coil assembly 5 is for obtaining a linear thrust force with the coil bobbin 5A based on the operating principle of the linear DC motor when energized. Of the coil 5B. Reference numerals 6A and 6B denote the coil assembly 5 shown in FIG.
A return spring (shown by a one-dot chain line) 7 for urging the right end of (A) has a rear end fixed to the coil assembly 5 and a front end thereof passing through an opening of a hook when the coil assembly 5 moves. The detection rod moves so as to come into contact with the outer peripheral portion of the bobbin thread wound around the bobbin inside.

Reference numeral 8 is a pressure sensor for detecting pressure by utilizing a change in resistance, a change in piezoelectric element or change in electric capacity,
Reference numeral 9 is a lower guide rod which is fixed to the yoke 10A defining the retracted end and serves to guide the movement of the coil assembly 5.

The yoke 10A is in contact with the longitudinal side surface of the iron core 4, and the yoke 10B is in contact with the second magnetic pole surface side of the permanent magnet and the side end surface of the yoke 10A. These come out of the permanent magnet and return to the permanent magnet. Not only does it serve as a path for the magnetic flux, but it also constitutes the frame of the lower thread remaining amount detecting device.

In the above bobbin thread detecting device, the permanent magnets 2A, 2B, the air gaps 3A, 3B, the iron core 4, the coil assembly 5, and the yokes 10A, 10B constitute a linear motor. As shown by reference numeral A in FIG. 3, this detection device has a bobbin 12 in which a lower thread 11 is wound inside a sewing machine.
Is installed at a position close to the pot 14 in which
When the bobbin thread is detected while the shuttle 14 is stopped, the current is applied to the coil of the coil assembly 5 in a predetermined direction from the state before the detection operation shown in FIG. When the solid 5 is moved forward, the detection rod 7 is inserted into the shuttle 14 as shown in FIG. 1B or 1C, and the lower thread 11 is detected. At this time, when the lower thread 11 is sufficiently left as shown in FIG. 3B, the tip of the detection rod 7 collides with the outer peripheral portion of the lower thread 11 to generate a small vibration wave. When the length is less than the specified length as described above, the winding diameter of the lower thread becomes small, so that the tip of the detection rod 7 cannot reach, and as a result, the coil assembly 5 itself collides with the front yoke (frame front end) 10A, A strong mechanical impact noise (vibration wave) is generated. In this way, the presence or absence of the lower thread can be detected based on the strength of the vibration wave when the detection rod 7 is moved forward.

Therefore, in the above bobbin thread detecting device, as shown in FIG.
As shown in the state of being attached to the attachment member 13 of the sewing machine main body, a vibration wave detecting element (ultrasonic sensor including a piezoelectric element) 15 is attached to the outside of the yoke 10B, and is detected by the vibration wave detecting element 15. The oscillating wave that is generated is identified by using two types of comparators having different reference voltages shown in the circuit diagram of FIG. 5, and the bobbin thread is detected.

That is, the reference voltage 100 shown in the upper part of FIG.
The detection signal from the ultrasonic sensor 15 is input to one input terminal of the comparator set to mV and the comparator set to the reference voltage 600 mV shown in the lower stage. The outputs of these comparators are connected to the inputs of separate monostable multivibrators (one-shot) LM555, and the one-shot outputs are identified by a determination circuit (not shown).

FIG. 6 shows two comparators having different reference voltages, which are obtained when the movable part (coil assembly) 5 is input from the ultrasonic sensor 15 to the vibration wave discrimination circuit.
Two one-shot output waveforms are shown. From this figure, when the detection rod advances and hits the lower thread 11, and when the coil assembly 5 returns and hits the rear wall (the rear end of the frame). , Only one shot on the side where the reference voltage is set to 100 mV outputs a pulse.

On the other hand, when the bobbin thread is less than the specified value, the vibration wave reaches a maximum value of 700 mV when the coil assembly 5 which is strongly urged advances and hits the front wall, so that the reference voltage is increased. Both the one-shot on the side set to 100 mV and the one-shot on the side set to the reference voltage 600 mV send output pulses. Therefore, the bobbin thread remaining amount detecting device already proposed by the applicant, which has been described in detail above, is
By combining the presence / absence of the outputs of the above two one-shot circuits and the forward / backward movement control of the coil assembly, it is possible to determine whether or not the lower thread is present and whether or not the forward / backward movement of the movable portion has been correctly performed. The ultrasonic sensor 15 can reliably identify.

The main hardware structure of the bobbin thread remaining amount detecting device of this embodiment and the basic operating principle thereof have been described above. The features of the bobbin thread remaining amount detecting device of this embodiment will be described in detail below.

FIG. 7 is a circuit diagram showing the essential parts of the vibration detecting portion and the drive control portion of the linear actuator which constitute the lower thread remaining amount detecting device of this embodiment, and FIG. 8 shows the winding of the linear actuator and the lower thread. It is a schematic sectional drawing which showed the positional relationship with the shuttle which accommodates a bobbin.

The bobbin thread remaining amount detecting device of the present embodiment has a main condition (not shown) of the sewing machine, in which the first condition is as follows.
First determining means for determining that the rotation speed of the main shaft for moving the needle up and down is in a low speed state in which the lower bobbin thread remaining amount can be detected;
As a condition, there is incorporated a second determination means for determining that the shuttle rotating in synchronization with the rotation of the main shaft is in a rotation angle range in which the detection rod can be introduced by the linear actuator from its opening. Only when the first condition and the second condition, which are the determination results by the determination means, are satisfied at the same time, the linear actuator is driven as described below to control the lower thread remaining amount detecting operation. .

Further, in the present embodiment, the comparator / one-shot circuit 16A shown in FIG. 7 is a vibration wave detection circuit during operation, and the reference voltage set for the comparator shown in the upper part of FIG. 5 is set to 100 mV. The comparator / one-shot circuit 16B is a vibration wave detection circuit without a bobbin thread, and corresponds to a circuit in which the reference voltage of the comparator shown in the lower part of FIG. 5 is set to 600 mV.

As shown in FIG. 7, the bobbin thread remaining amount detecting device of this embodiment is an ultrasonic sensor (vibration wave detecting means) 15
The level of the detection signal input from is compared with the reference level of 100 mV, and if it exceeds the reference level, the comparator / one-shot circuit 16A that outputs a one-shot signal is compared with the reference level of 600 mV. , A comparator / one-shot circuit 16 which outputs a one-shot signal when the reference level is exceeded.
B, a programmable controller (CTL) 17 for generating various control signals described later based on signal inputs from the one-shot circuits 16A and 16B, and an actuator driver controlled based on the control signals from the controller 17. 18 and a linear actuator 19 (corresponding to the one indicated by the symbol A in FIG. 3 and the like) controlled and driven by the driver 18 as main parts,
Further, a start switch 20 for instructing start and reset is attached to the programmable controller 17.

This embodiment is a bobbin thread remaining amount detecting device applied to a so-called horizontal shuttle sewing machine, and the linear actuator 19 is arranged at a position shown in FIG. 8 with respect to the shuttle. That is, reference numeral 21 in the drawing is a shuttle shaft base, and the outer shuttle 14 is rotatably supported around the shaft supported by the shuttle shaft base 21 so as to rotate in the direction of the arrow. A linear actuator 19 to which 15 is attached is arranged. Further, in the figure, the shaded portion 22 is the upper thread hook over portion of the outer hook 14, and 23 is the sword tip portion for hooking the upper thread during sewing.

In the present embodiment, the linear actuator 19 is arranged at the arrangement position as shown in FIG. 8 because of the space.
Also, in a normal sewing machine, the outer hook 14 is rotated by 2 times while the main shaft makes one revolution.
It is designed to rotate. Therefore, it is possible to move the detection rod forward into the lower thread hook while avoiding the sword point portion 23 of the outer hook 14 and the upper thread hook over portion 22 at a rotation angle of the upper shaft (spindle) of the sewing machine.
90 ° between 65 ° and 255 ° and 345 ° and 75 °. In this angle range, the forward movement position A of the detection rod 7 by the linear actuator in FIG.
It corresponds to being in the range of 180 ° of B to C that can be inserted inside, and in terms of time, when the rotation speed of the upper shaft is 300 rpm, it corresponds to a period of 50 msec. The linear actuator 19 used in the present embodiment operates in 18 msec or less from the start of driving to the return because the mass of the movable portion including the detection rod 7 is as small as 2 g or less. The remaining amount of the bobbin thread can be reliably detected even during rotation of the.

Actually, the rotation angle range is 165
Since the upper thread is included in the period in which the upper thread passes through the hook in the range of ° to 255 degrees, the upper thread is caught by the detection rod 7 if the actuator is operated during this period, and therefore the main shaft is 34
Actuator 1 when in the angle range of 5 ° to 75 °
9 will be activated. However, since this period corresponds to a period in which the bobbin thread is being fed out, a normal solenoid has a long contact time with the bobbin thread, which causes a problem in sewing. Since the vibration wave when the bobbin comes into contact with the bobbin thread is immediately retracted, the bobbin thread remaining amount can be detected even when the sewing machine is rotating, without affecting the sewing quality. There is.

In the present embodiment, the timer of the CTL 17 is used to detect the drive of the linear actuator 19 and the normal / abnormal state of the bobbin thread detecting operation, which is shown in the time charts of FIGS. (1) generation of drive output for forward and backward movement of the actuator, and determination of normal operation when there is a bobbin thread, (2) determination of no bobbin thread,
The generation of control signals used for each of (3) determination of reverse movement abnormality and (4) determination of forward movement abnormality will be described.

In the detection device of this embodiment, when the lower thread is less than the specified amount, the coil assembly 5 is moved to the front wall (yoke 10).
Actuator driver 1 just before hitting A)
The forward signal output to 8 is set to be off.

From the control device of the sewing machine main body, when the rotation speed of the main shaft becomes a low speed state where the lower thread can be detected, for example, 300 rpm, a start signal is input and the start switch 20 is turned on. When the start switch 20 is turned on, the input relay 0001 of the CTL 17 is turned on and the program starts.

As described above, when the main spindle rotation speed (rotation speed) of the sewing machine becomes equal to or less than the specified rotation speed, the main spindle rotation angle becomes 345.
The rotation angle signal (detectable signal) is output from the control circuit of the sewing machine main body only to the programmable controller 1
No. 7 input relay 0001 is output. This rotation angle signal may be normally output once, but may be output several times if the rotation state below the specified rotation number continues for a long time. The operation of outputting the rotation angle signal is repeated when the main spindle rotation speed of the sewing machine becomes equal to or higher than the specified rotation speed and becomes equal to or lower than the specified rotation speed.

In FIG. 9, when the rotation angle signal is output and the input relay 0001 of the programmable controller 17 is turned on, the forward drive timer T000 is started. When the timer T000 is turned on, the forward end timer T001, the backward drive timer T002, the backward end timer T003, the collision wait timer T004, and the reset timer T005 are programmed to start sequentially in this order.

The forward drive timer T000 is turned on, the forward drive end timer T001 is turned off, and the internal relay 1102 for forward drive check is turned off, and the output relay 0500 is turned on. When this output relay 0500 is turned on, the linear actuator is activated. At 19 the advancement of the coil assembly begins. When the tip of the detection rod 7 comes into contact with the lower thread, an operation signal is output from the comparator / one-shot circuit 16A. When this signal is input to the controller 17 and the input relay 0002 is turned on, the internal relay 1102 is held on. Then, as described above, the output relay 0500 is turned on by the AND of the timer T000 being turned on, the timer T001 being turned off, and the internal relay 1102 being turned off. Therefore, when the internal relay 1102 is turned on,
The output relay 0500 is turned off and the forward drive is interrupted.

One-shot circuit 16A due to forward movement error
If the operation pulse signal from is not output, the output relay 0500 is turned on only from the time when the timer T000 is turned on until the timer T001 is turned on.
Next, the driving is suspended until the reverse start timer T002 is turned on. This is the time for preventing the driver circuit from being temporarily short-circuited because the actuator driver is of the bipolar drive type.

From the time when the timer T002 is turned on until the time when the timer T003 is turned on, the output relay 0501 for the backward movement is turned on and the backward movement of the coil assembly is performed.

When the coil assembly retracts and collides with the rear case, the operation signal from the one-shot circuit 16A is output again and the input relay 0002 is turned on. As a result, the state in which the internal relay 1103 for reverse check is turned on is held. In addition, this internal relay 11
02 or internal relay 1103 is off and timer T0
Since 04 is turned on, the internal relay 1105 for the abnormal operation signal is kept in the on state. Therefore, in normal operation, this internal relay 11
Output relay 050 for abnormal operation signal while 05 remains off
No. 3 is not turned on, no operation error signal is output, control ends, and the state returns to the initial state.

In the present embodiment, as described above, CT
L17 drives the linear actuator forward,
When the vibration generated when the detection rod 7 is moved forward into the shuttle is generated when the specified amount of bobbin thread is present, the linear actuator is immediately controlled to retreat. Therefore, the bobbin thread is driven. The remaining amount detection operation can be executed at high speed. Then, the same control is performed in the case where there is no lower thread next.

FIG. 10 shows a signal generated when there is no lower thread, and a pulse signal is output from the comparator one-shot circuit 16B to input the relay 000 of the CTL 17.
When 2 is turned on, the internal relay 1100 of the CTL 17 is held in an on state, and as a result, the output relay 0502 is turned on and a bobbin thread-free signal is output, which is displayed.

FIG. 11 shows a signal generated at the time of the backward movement error. As described above, if the second pulse is not input to the input relay 0002 between the timer T002 ON and the timer T004 ON, the internal relay 1103. Is not held, the internal relay 1105 for the reverse abnormality signal is held, the output relay 0503 is turned on, an operation error signal is output, and the display is displayed.

FIG. 12 shows a signal generated at the time of forward movement error. Since the input relay 0002 receives no pulse signal, it is not held by the internal relays 1102 and 1103. Therefore, the internal relay 1105 enters the holding state, the output relay 0503 is turned on, and the operation error signal is output.

FIG. 13 is a flow chart collectively showing the drive operation executed by the control signal shown in the time charts of FIGS. 9 to 12 described above and the determination operation in accordance with the flow of time. Step S1 The operations are performed in the order of to S11, and the presence or absence of the lower thread remaining amount and the forward / backward operation abnormality are detected during the operation of the sewing machine.

That is, the main control unit of the sewing machine determines that the low-speed rotation state in which the detection operation is possible is made, the start signal of the bobbin thread detection operation is input to the input relay 0001, and after the start, the main control apparatus is started. Then, when the rotation angle signal indicating that the detection rod is in the range of the rotation angle capable of moving forward is input (step S1), the forward drive timer T000 is turned on (step S2). When this forward drive timer is turned on, a forward signal is output from the output relay 0500, and the one-shot circuit 16A is output even while the timer is on.
The operation pulse signal (vibration detection signal) from the input relay 00
When it is input to 02, the forward drive is forcibly turned off (steps S3 and S4). While the forward drive timer is ON, if the operation signal is not output even if the forward drive signal is output (step S3), the forward drive error, that is, the operation error signal is output and displayed (steps S5 and S6).

When the backward drive timer T002 is turned on after the forward drive timer is turned off in step S4 (step S7), the backward signal is output while the timer is on, but the operation signal is input. When the input relay 0002 is turned on, the normal operation is completed (step S8). If no operation signal is input in step S8, a backward error,
That is, an operation error is output (steps S9 and S6).
Further, when a large vibration wave is detected while the forward drive timer is ON in step S2 and a signal is input from the one-shot circuit 16B, the thread absence signal input relay 0003 is turned on and the bobbin thread absence signal is output. (Steps S10 and S1
1), a lower thread error is output and displayed (step S1)
1).

As described above in detail, in the present embodiment, at the rotation speed of the sewing machine that does not affect the sewing operation, and the rotation angle of the main shaft is within the range in which the opening of the outer hook can advance the detection rod. At a certain time, the lower thread remaining amount is detected, and if a vibration wave generated when the movable part is blocked from advancing is caught, the forward drive is immediately turned off to retreat, so the sewing machine is stopped. It is possible to reliably detect the remaining amount of the lower thread.

FIG. 14 is a block diagram showing a schematic structure of a lower thread remaining amount detecting device according to a second embodiment of the present invention, and FIG. 15 is a sectional view showing a relationship between a detecting portion and a shuttle. 16 is the front view.

The bobbin thread remaining amount detecting device of this embodiment is shown in FIG.
As shown in FIG. 3, a detection unit 33 including a detection rod 31 and a detection rod driving device 32 is provided, and a hook 34 is provided by a detection operation described later.
The detection rod 31 is moved forward into the interior of the
The amount of forward movement of the bobbin wound around the bobbin 37 accommodated in the shuttle 34 is detected by the lower bobbin thread remaining amount calculation section 36 based on the detection result. Has become.

Further, the detection operation of the detection unit 33 is controlled by the main control unit 38, and the main control unit 38 has the opening of the rotating outer pot and the detection rod 31. When the opening position detecting portion 38A for detecting that there is a positional relationship capable of moving forward and the detection rod 31 are moved forward into the shuttle,
A detection rod contact detection unit 38B that detects that the tip of the sewing machine comes into contact with the outer circumference of the bobbin thread wound on the bobbin, and a spindle that determines that the rotation speed of the sewing machine spindle is within a speed range in which the detection operation is possible. The rotation speed determination unit 38C is built in.

First, with reference to FIG. 15 and FIG. 16, the detection unit 33 and the relationship between the detection unit 33 and the shuttle 34 will be described in detail.

The detecting portion 33 is the fixed plate 4 of the sewing machine main body.
0, and the detection unit 33 is guided by a guide 42 in the vertical direction in the figure, and a rotary solenoid (detection rod drive means) 46 for driving the detection rod 31 forward and backward through an arm 44. And the arm 44
A detection rod holder 47, to which the detection rod 31 is fixed, is rotatably connected to the tip of the. Further, a magnet holder 50 having a permanent magnet 48 fixed at the tip thereof is provided at the center of the detection rod 31.
Is attached to the magnet holder 50 and the detection rod holder 4
Two springs 52 are installed between the springs 7 and 7 with the detection rod 31 in between. Further, as can be seen from FIG. 16, the permanent magnet 48 is provided so as to face the Hall element 53, and the generated voltage of the Hall element 53 changes according to the movement amount of the detection rod 31, so that the generated voltage is Based on this, the amount of forward movement of the detection rod 31 can be detected.

In the upper part of FIG. 15, there is shown a shuttle 34 in which a bobbin whose lower thread remaining amount is detected by the detecting section 33 is housed. The shuttle 34 moves up and down the needle as the sewing machine spindle rotates. It is provided with an outer hook 54 that is rotatable in synchronism with movement, and an inner hook 56 that is held stationary inside the outer hook 54. A bobbin case 60 having an opening 58 formed on a side surface is detachably mounted inside the inner hook 56, and a bobbin 37 having a bobbin thread 61 wound around the bobbin case 60 is detachable and rotatable. It is designed to be housed in a condition that allows it.

In the present embodiment, as will be described in detail later, when the detection rod 31 is driven to move forward by the rotary solenoid 46, it can be moved forward into the shuttle and is shown by a chain double-dashed line in FIG. The timing at which the outer hook opening 62 formed in the outer hook 54 and the opening 58 of the bobbin case 60 coincide with the forward position of the detection rod 31 is detected,
Only at this timing, the detection unit 33 is driven to detect the remaining amount of lower thread by the detection rod 31.

This detection operation will be described. When the opening 58 of the bobbin case and the outer hook opening 62 have a positional relationship as shown in FIG. 15, the rotary solenoid 46 is excited to rotate the arm 44 counterclockwise. Then, by moving the detection rod holder 47 upward, the magnet holder 50 and the detection rod 31 fixed to the magnet holder 50 are moved upward via the spring 52 as shown by the arrow.

As a result, the detection rod 31 advances into the shuttle through the two openings 58 and 62, as shown by the two-dot chain line, and the tip of the detection rod 31 is wound on the bobbin 37. Abut. Therefore, if the position of the detection rod 31 at this time is detected by the Hall element 53, the remaining amount of the lower thread 61 can be obtained. Further, since the spring 52 is interposed between the detection rod holder 47 and the magnet holder 50, the detection rod 3
It is possible to mitigate the impact when 1 touches the outer circumference of the lower thread 61.

When the rotary solenoid 46 is demagnetized after the detection rod 31 contacts the outer circumference of the lower thread 61 as described above,
Since the arm 44 returns to the original position by the action of the built-in spring (not shown), the detection rod 31 also moves to the original position and is housed inside the detection rod guide 42, and one detection operation is performed. finish.

FIG. 17 is a block diagram showing the outline of the overall construction of a sewing machine to which the lower thread remaining amount detecting device of this embodiment is applied.

As shown in FIG. 14, the detector 33 is connected to the main controller 38 in a state capable of transmitting and receiving signals. The main controller 38 includes an I / O port 64 for inputting / outputting signals to / from an external device, a CPU (central processing unit) 66 for performing various arithmetic processes, the opening position detecting section 38A, and a detection rod. ROM (read only memory) in which programs used for the processes executed by the contact detection unit 38B and the spindle rotation speed determination unit 38C and various programs used for the bobbin thread remaining amount detection process described later are stored.
68, a RAM (random access memory) 70 for temporarily storing various data, and the I / O port 64
The CPU 66, the ROM 68, and the RAM 70 are electronic control circuits that are electrically connected by a bus line to transmit and receive signals.

The main controller 38 functions to control the operation of the entire sewing machine, and sends a control signal from the I / O port 64 to the drive circuit 76 for driving the motor 74 for rotating the main shaft of the sewing machine head 72. The pedal 7 for outputting and activating the sewing operation of the sewing machine is output to the I / O port 64.
The ON / OFF signal from the control unit 8 and the rotation angle of the main shaft of the sewing machine head 42 detected by the rotary encoder 80 are input. Then, to the detection unit 33, a control signal is output from the main control device 38 to the drive circuit 82 of the rotary solenoid 46, and the hall element 53.
The detected voltage is amplified by the amplifier circuit 84, converted into a DC voltage by the A / D converter 86, and then input to the control device 38.

Further, this sewing machine is provided with a display panel 90 (a concrete structure is not shown), and the detection level indicator 91 for displaying the degree of the detected lower thread remaining amount is displayed on the display panel 90. Is provided, and the main controller 38 is provided.
The signal is transmitted and received to and from the display panel 90.

On the display panel 90, in addition to the display detection level 91, a setting operation key 94 used when setting / changing the detection level, and when the bobbin thread remaining amount falls below the setting level. A buzzer 92 that generates an alarm sound, a lower thread warning lamp 93 that also lights when the remaining amount falls below a set level, a reset key 95 that stops the buzzer 92, and a tip of the detection rod 31 when there is no lower thread There are a 0% setting key 96 for storing the generated voltage of the hall element 53 when the bobbin 37 is in contact with the bobbin 37 and a 100% setting key 97 for storing the generated voltage when the bobbin 37 is wound with the maximum bobbin thread. Each is provided.

In the present embodiment, first, before starting sewing, an empty bobbin 37, in which the lower thread 61 is not wound, is mounted in the hook 34, and the outer hook 54 is stopped at 0%.
By operating the setting key 96 to drive the detection unit 33, the generated voltage of the hall element 53 when the detection rod 31, the opening 58 and the outer pot opening 62 are in the same state as shown in FIG. Remember. FIG. 18 shows the voltage generated by the Hall element 53 when the rotary solenoid 46 is excited and the detection rod 31 is inserted into the shuttle 34.
It is shown that it changes almost linearly according to the amount of advance of 1. That is, in the figure, a is the standby position of the detection rod 31 before the rotary solenoid 46 is excited, and d is the detection rod 31.
Corresponds to the 0% position where the tip end of the contact point comes into contact with the bobbin 37's bobbin winding surface, and Va and Vd represent voltages generated at the respective positions.

After the above 0% setting is completed, the bobbin in which the bobbin thread 32 is maximally wound is mounted in the hook 34, and the above 100% is set.
The output voltage of the Hall element 53 at the 100% position is similarly stored in the RAM 70 by operating the setting key. This 100%
The position corresponds to b in FIG. 18, and the generated voltage at that time is Vb.
It is. The voltages Vb and Vd at each of the 0% and 100% positions obtained as described above are used in the arithmetic processing performed for the display of the detection level indicator 91.

Further, the setting operation key 90 is used to set a determination voltage for determining that the remaining amount of the bobbin thread has reached the specified amount. This judgment voltage is V at the position of c in FIG.
At c, when the generated voltage of the Hall element 53 at the time of detection reaches this Vc, the buzzer 92 is generated and the lower thread warning lamp 93 is turned on.

After performing the above-mentioned preparatory operation, the pedal 7
When sewing is started by stepping on 8, the detecting operation is executed according to the flowchart of FIG.

First, the pedal is depressed and the pedal signal is turned on.
It is determined that the number of revolutions (speed) of the sewing machine has become equal to or less than a predetermined number of revolutions in the state of step S20,
21). This determination is performed by the main spindle rotational speed determination unit 38C in consideration of the performance of the driving device and the like, and the actual rotational speed (rotational speed obtained from the rotational angle signal input from the rotary encoder 80). Speed).

When it is determined in step S21 that the sewing machine rotational speed is lower than the reference, it is detected that the opening 58 of the bobbin case and the outer hook opening 62 have reached the advanceable position of the detection rod 31. (Step S22). This position detection can be detected by the detection rod contact detection unit 38B because the rotation angle signal (timing signal) of the sewing machine main shaft input from the rotary encoder 80 has reached a preset reference value. Has become.

When the two conditions are satisfied in steps S21 and S22, the rotary solenoid 46 is excited (step S23), and the detection rod 31 coincides with the opening 58 of the bobbin case. Introduced from 62, the actual generated voltage Vr of the Hall element 53 at that time is read in a minute cycle (step S24), and is read in the RAM.
It is stored in 70 and it is detected that the tip of the detection rod 31 is in contact with the outer circumference of the lower thread (step S25).

This detection is performed by the detection rod contact detection section 38B.
The change in the generated voltage of the Hall element 53 per unit time, which is executed in step S4, is calculated, and the amount of change is detected as being lower than a preset reference value.

When it is detected in step S25 that the tip of the detection rod 31 has come into contact with the outer circumference of the lower thread, the rotary solenoid 46 is immediately demagnetized and the detection rod 31 returns to the original standby position.

Next, the generated voltage Vr of the Hall element 53 read at the time of the bobbin thread contact is compared with the reference voltage Vc (step S27). If Vr ≧ Vc, the buzzer 92
To activate the lower thread warning lamp 93 (step S28). If Vr <Vc in step S27, the process returns to step S20 and the above operation is repeated.

As described in detail above, according to this embodiment,
A range of rotation angles at which the rotation speed of the sewing machine spindle can be measured at a low speed and the detection rod can be advanced into the hook 34 (the opening 58 of the bobbin case and the outer hook opening 62 match the advanceable position of the detection rod 31). The state where the shuttle 34 has reached the above condition), the detection operation is started by the detection unit 33, and at the same time when the tip of the detection rod 31 comes into contact with the outer circumference of the bobbin thread, the detection rod 31 is retracted to the original state. Since it is made to return to the position, it cannot be applied at the same high speed as in the case of the first embodiment using the linear actuator that can make the movable part extremely lightweight, but similarly, during the sewing operation, that is, the shuttle 34 is rotating. Even at this time, it is possible to detect the remaining amount of lower thread.

Further, according to this embodiment, since the lower thread remaining amount can be detected periodically without the operator being aware, it is possible to reliably prevent the yarn breakage in the middle. .

FIG. 20 is a cross-sectional view corresponding to FIG. 15 showing a detecting portion provided in the lower thread remaining amount detecting device according to the third embodiment of the present invention.

The detection unit 33 of this embodiment has an ultrasonic sensor 98 at the tip of a guide 42 for guiding the detection rod 31.
Is provided, and a stopper 99 with which the magnet holder 50 abuts is provided at the inner tip of the guide 42 before the tip of the detection rod 31 abuts the bobbin thread when the bobbin thread remaining amount below a specified amount. Except for that, it is substantially the same as the detection unit 33 of the second embodiment.

In the present embodiment, the main controller 38 is also used.
A detection signal from the ultrasonic sensor 98 is input to the detection rod contact detection unit 38B, and the detection rod contact detection unit 38B detects that the tip of the detection rod 31 is in contact with the lower thread. However, it is also determined that the remaining amount of the bobbin thread has fallen below a specified amount.

That is, when the remaining amount of the bobbin thread is more than the specified value, the tip of the detection rod 31 comes into contact with the outer circumference of the bobbin thread, and a small vibration with a long cycle is generated. Since it abuts against, a large vibration with a short cycle is generated. Therefore, the ultrasonic signal detected by the ultrasonic sensor 98 is input to the main controller 38 and, at the same time, the detection rod 31 is driven backward, and the amplitude and cycle of the input ultrasonic signal are different. It is possible to detect the presence or absence of the lower thread remaining amount by performing frequency analysis by FFT (Fast Fourier Transform) and determining from which frequency characteristic the detected vibration is caused by the obtained frequency characteristic. .

Therefore, in the present embodiment, step S25 of the flowchart of FIG. 19 is replaced with "whether vibration is detected", and step S27 is replaced with "whether the vibration is in contact with the stopper". As in the case of the form, the lower thread remaining amount can be reliably detected during sewing. In addition, in step S27 of the present embodiment,
The determination of “Vr ≧ Vc” in the case of FIG. 19 may be simultaneously executed.

The present invention has been specifically described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention.

In the case of the first embodiment, for example, the low-speed rotation speed of the sewing machine spindle as the first condition is not limited to that shown in the above-mentioned embodiment, and is set to an arbitrary speed according to the performance of the linear actuator. can do.

It goes without saying that the range of the spindle rotation angle as the second condition can be changed according to the type of sewing machine.

As the ultrasonic sensor, the above-mentioned piezoelectric element is preferable because it is small and has excellent oil resistance. However, the ultrasonic sensor is not limited to this and can be distinguished from the vibration wave generated during normal sewing work. Possible, for example 200-250KH
The sensor is not particularly limited as long as it can detect z.

Further, the specific structure of the linear actuator for moving the detection rod forward and backward is not limited to that described above.

In the case of the second or third embodiment, for example, the detection rod drive means is not limited to that shown in the above embodiment, and a drive device using another rotary solenoid may be used. Alternatively, the driving device may be based on another principle.

In the above embodiment, the sewing machine using the bobbin case has been described, but it goes without saying that a sewing machine not using the bobbin case may be used.

The detection of the remaining amount of the bobbin thread performed during the sewing operation is
The method is not limited to automatic execution, and may be appropriately performed by a manual operation by an operator such as pressing a detection button.

[0098]

As described above, according to the first aspect of the invention, the tip of the detection rod is brought into contact with the outer peripheral portion of the thread wound around the bobbin without stopping the sewing machine, and the lower thread remains. The amount can be detected accurately.

According to the invention of claim 2, the linear actuator can be reliably operated at high speed.
The bobbin thread remaining amount can be accurately detected without stopping the sewing machine.

According to the third or fourth aspect of the invention, even when the sewing machine is performing the sewing operation, the detection rod can be advanced into the shuttle and the lower thread remaining amount can be detected.

According to the fifth aspect of the invention, the operation can be performed at a rotational speed at which the detection operation can be reliably performed according to the performance of the detection rod drive means. Therefore, the operation can be performed accurately and safely. The remaining amount of yarn can be detected.

According to the sixth aspect of the invention, even with a normal sewing machine using a bobbin case, it is possible to reliably detect the lower thread remaining amount during operation.

According to the invention of claim 7, since the rotation angle of the main shaft can be detected and whether the opening of the outer pot is at the position where the detection rod can be advanced or not can be accurately determined from the detected value, the operation can be performed reliably even during operation. The lower bobbin thread remaining amount can be detected.

According to the invention of claim 8, the operator can easily grasp the remaining amount of the lower thread.

[Brief description of drawings]

FIG. 1 is a plan view, a sectional view, and a front view showing a schematic configuration of a lower thread remaining amount detecting device according to a first embodiment.

FIG. 2 is a perspective view showing the lower thread remaining amount detecting device according to the first embodiment with a part thereof broken away.

FIG. 3 is a schematic cross-sectional view showing the relationship between the bobbin thread remaining amount detection device of the first embodiment and a bobbin case accommodated in the shuttle.

FIG. 4 is a front view showing a state in which an ultrasonic sensor is attached to the lower thread detection device of the first embodiment.

FIG. 5 is a circuit diagram showing a vibration wave identifying circuit incorporated in the lower thread remaining amount detecting device according to the first embodiment.

FIG. 6 is a diagram showing a vibration waveform detected by the vibration wave identifying circuit.

FIG. 7 is a circuit diagram showing main parts of a detection unit and a drive control unit incorporated in the lower thread remaining amount detection device of the first embodiment.

FIG. 8 is a schematic cross-sectional view showing a positional relationship between a linear actuator and a shuttle for accommodating a bobbin thread bobbin.

FIG. 9 is a time chart illustrating generation of drive signals for forward movement and backward movement, and normal operation when a bobbin thread is present.

FIG. 10 is a time chart illustrating generation of a control signal for determining the absence of a lower thread.

FIG. 11 is a time chart explaining generation of a control signal at the time of a backward movement error.

FIG. 12 is a time chart illustrating generation of a control signal when a forward movement error occurs.

FIG. 13 is a flowchart showing the flow of a lower thread remaining amount detecting operation according to the first embodiment.

FIG. 14 is a block diagram showing a schematic configuration of a lower thread remaining amount detecting device according to a second embodiment.

FIG. 15 is a cross-sectional view showing a detector and a hook of a lower thread remaining amount detector according to a second embodiment.

FIG. 16 is a front view showing a detector and a hook of the yarn remaining amount detecting device of the second embodiment.

FIG. 17 is a block diagram showing a schematic configuration of the entire sewing machine to which the bobbin thread remaining amount detection device according to the second embodiment is applied.

FIG. 18 is a diagram for explaining the principle of detecting the remaining amount of lower thread by the Hall element.

FIG. 19 is a flowchart showing the operation of the second embodiment.

FIG. 20 is a cross-sectional view showing a detection unit included in the lower thread remaining amount detection device according to the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Detection rod bearing 2A, 2B ... Permanent magnet 3A, 3B ... Air gap 4 ... Iron core 5 ... Coil assembly 5A ... Coil bobbin 5B ... Coil 6A, 6B ... Return spring 7 ... Detection rod 8 ... Pressure sensor 9 ... Lower guide rod 10A 10B ... Yoke 11 ... Lower thread 12 ... Bobbin 13 ... Mounting member 14 ... Kettle 15 ... Vibration wave detection element (ultrasonic sensor) 16 ... Comparator / one-shot circuit 17 ... Programmable controller (CTL) 18 ... Actuator driver 19 ... Linear Actuator 20 ... Start switch 21 ... Hook shaft base 22 ... Upper thread hook crossing portion 23 ... Sword tip 31 ... Detecting rod 32 ... Detecting rod drive device 33 ... Detecting portion 34 ... Rocket 35 ... Introduced amount detecting portion 36 ... Bottom thread remaining amount Calculation unit 37 ... Bobbin 38 ... Main control device 38A ... Opening position detection unit 38B ... Detection rod contact detection unit 38C ... Spindle speed Tough 46 ... Rotary Solenoid 48 ... permanent magnet 52 ... outer hook opening 53 ... Hall elements 54 ... outer hook 58 ... opening 60 ... bobbin case 80 ... rotary encoder 91 ... detection level indicator 98 ... ultrasonic sensor 99 ... stopper

Claims (8)

[Claims] 1. A bobbin thread remaining amount detecting device for a sewing machine for detecting a bobbin thread remaining amount by advancing a detection rod from an opening of an outer hook in a hook containing a bobbin wound with a bobbin thread of a sewing machine. , It is determined that the rotation speed of the linear actuator that is installed at a predetermined position with respect to the shuttle and that moves the detection rod forward and backward, and the main shaft that moves the needle up and down are in a speed state that can detect the lower bobbin thread remaining amount. A first determining means; a second determining means for determining whether the shuttle rotating in synchronization with the rotation of the main shaft is in a rotation angle range in which the detection rod can be advanced by the linear actuator from the opening of the outer shuttle; When the determination result by the determination unit and the determination result by the second determination unit are satisfied at the same time, the control unit drives the linear actuator to control the lower thread remaining amount detecting operation. Detection of remaining amount of bobbin thread on sewing machine apparatus. 2. A bobbin thread remaining amount detecting device for a sewing machine, which detects a bobbin thread remaining amount by advancing a detection rod from an opening of an outer hook in a bobbin in which a bobbin wound with a bobbin thread of a sewing machine is accommodated. , It is determined that the rotation speed of the linear actuator that is installed at a predetermined position with respect to the shuttle and that moves the detection rod forward and backward, and the main shaft that moves the needle up and down are in a speed state that can detect the lower bobbin thread remaining amount. A first determining means; a second determining means for determining whether the shuttle rotating in synchronization with the rotation of the main shaft is in a rotation angle range in which the detection rod can be advanced by the linear actuator from the opening of the outer shuttle; When the determination result by the determination unit and the determination result by the second determination unit are satisfied at the same time, the linear actuator is driven to control the lower thread remaining amount detection operation, and the linear actuator is driven to move forward. movable part And a means for detecting a vibration wave generated when the fixed detection rod is moved forward into the shuttle with and without a specified amount of bobbin thread. A bobbin thread remaining amount detecting device for a sewing machine, wherein when any one of the above vibration waves is detected when the actuator is driven forward, control is performed to drive the linear actuator backward. 3. A bobbin thread remaining amount detecting device for a sewing machine, which detects a bobbin thread remaining amount by advancing a detection rod from an opening of an outer hook in a hook containing a bobbin wound with a lower thread of a sewing machine. In the above, the detection rod drive means for moving the detection rod forward and backward, the means for detecting that the opening of the rotating outer pot is in a position where the detection rod can be advanced, and the detection rod was moved forward into the pot. When the outer hook is in a position where the detection rod can be advanced inside the hook, the detection rod is provided with a means for detecting that the tip of the needle touches the outer circumference of the bobbin thread wound on the bobbin. The sewing machine is characterized in that when the detection means advances the detection rod by the driving means and the tip of the detection rod comes into contact with the outer circumference of the bobbin thread, the detection operation of retracting the detection rod is executed. Lower thread remaining amount detection device. 4. A bobbin thread remaining amount detecting device for a sewing machine for detecting a bobbin thread remaining amount by advancing a detection rod from an opening of an outer hook in a hook in which a bobbin wound with a bobbin thread of a sewing machine is accommodated. In the above, the detection rod driving means for moving the detection rod forward and backward, the means for detecting that the opening of the rotating outer pot is in a position where the detection rod can be advanced, and the detection rod was moved forward into the pot. At this time, a means for detecting that the front end of the bobbin is in contact with the outer circumference of the bobbin thread, or the movable part that moves together with the detection rod is in contact with the stopper part is provided. When the detection rod is in a position where it can be moved forward in the shuttle, the detection rod drive means may move the detection rod forward so that its tip comes into contact with the bobbin thread outer periphery or the movable part comes into contact with the stopper. When it is detected, the detection operation of retracting the detection rod is executed. A bobbin thread remaining amount detecting device for a sewing machine characterized by the above. 5. The method according to claim 3, further comprising means for determining that the rotation speed of the sewing machine spindle is in a speed state in which the detection operation is possible, and the rotation speed of the sewing machine spindle is in the speed state. A bobbin thread remaining amount detecting device for a sewing machine, wherein a detecting operation is executed when the bobbin thread remaining amount is detected. 6. The bobbin accommodated in a bobbin case according to claim 1, 2, 3 or 4, wherein the detection operation is performed when an opening of the bobbin case and an opening of the outer hook are aligned with each other. A bobbin thread remaining amount detecting device for a sewing machine, characterized in that 7. The method according to claim 1, 2, 3 or 4, wherein the timing for driving the detection rod forward is determined based on a timing signal corresponding to the rotation angle of the sewing machine main shaft. A lower thread remaining amount detecting device for a sewing machine. 8. A bobbin thread remaining amount detecting device according to claim 1, further comprising a detection level display means for displaying a degree of the detected bobbin thread remaining amount.