JPH0532075Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention relates to a bobbin thread remaining amount detection device for a sewing machine.

Specifically, the present invention relates to a lower thread remaining amount detection device for a sewing machine that can reliably detect the remaining amount of lower thread without causing false detection.

(Prior Art) A conventional lower thread remaining amount detection device for a sewing machine is shown in FIG.

A conventional bobbin thread remaining amount detection device of a sewing machine is attached to a sewing machine body, and presses the bobbin 1a in conjunction with the operation of a bobbin 1a that accommodates the bobbin thread and a thread trimming device (not shown) accompanying a thread trimming operation. , a detection member 2a that detects the remaining amount of bobbin thread in the bobbin 1a, and a detection member 2a.
a sensing member 3a that detects the amount of movement by the positional movement of a magnet 21a fixed to a part of the sensing member 1a;
and an alarm device 5a that issues an alarm by operating the sensing member 3a.

(Problem to be solved by the invention) Normally, when an industrial sewing machine sequentially sews a large number of objects to be sewn, each time the sewing of one object is finished, it prepares to move on to the next sewing process. The thread connected to the sutured end is cut using a thread cutting device. In this case, in order to prevent the bobbin thread stored in the bobbin 1a from breaking during the next suturing process,
By operating the detection member 2a when the thread cutting device is activated and pressing the bobbin 1a with the tip of the detection member 2a, the remaining amount of the bobbin thread can be ascertained in advance and the remaining amount of the bobbin thread can be detected when the remaining amount of the bobbin thread is low. In this case, the amount of movement of the detection member 2a is detected by the detection member 3a, and the alarm device 5
A is issued to notify the workers.

In this case, when the thread trimming device is activated, the detection member 2a forcibly presses the bobbin thread in the bobbin 1a in a direction that reduces the remaining amount of bobbin thread, so even if there is a large amount of bobbin thread remaining in the bobbin 1a, it can be detected. The movement of the magnet 21a of the member 2a becomes as shown by the solid line in FIG.
There is a problem in which the warning device is activated due to false detection in a, assuming that the remaining amount of bobbin thread is low.

The present invention provides a configuration that prevents false detection by a detection member that presses the bobbin thread in the bobbin in the compression direction when the thread trimming device performs thread trimming operation.

[Structure of the invention] (Means for solving the problems) The present invention provides the following means to solve the above-mentioned conventional problems.

That is, the bobbin thread remaining amount detection device of the sewing machine of the present invention is as follows:
The bobbin body is composed of a bobbin body having a central guide shaft, a fixed flange portion fixed to an end of the central guide shaft, and a movable flange portion movably held on the central guide shaft, the fixed flange portion and the movable flange portion. a bobbin that stores the bobbin thread between the bobbin and the bobbin, and a detection member that presses the movable flange of the bobbin in conjunction with the operation of the thread trimming device to detect the remaining amount of bobbin thread in the bobbin; a sensing means that activates and issues a signal when the amount of movement of the sensing member exceeds a predetermined value; a control section that issues a signal when the signal from the sensing means continues for more than a predetermined time; and an alarm when receiving the signal from the control section. It is characterized by comprising an alarm device that emits an alarm.

In the device of the present invention, the detection member is driven in conjunction with the operation of the thread trimming device as the thread trimming operation is performed, and after the movable flange is pressed with an impact, it is detected that the movable flange is pressed under almost constant load. The remaining amount of the bobbin thread accommodated between the movable flange portion and the fixed flange portion is detected by the detection member. And since the configuration is such that an alarm can be issued only when the amount compared with the preset amount of movement of the detection unit and the actual amount of movement of the detection unit is greater than or equal to the set value, the bobbin thread stored in the bobbin The alarm device operates only when the remaining amount of bobbin thread is low, and when there is a large amount of bobbin thread remaining, the alarm device will not generate a false alarm even if the detection member acts on the method of compressing the bobbin thread. .

The bobbin thread remaining amount detection device for a sewing machine according to the present invention includes a bobbin, a detection member, a sensing member, a control section, and an alarm device.

The bobbin is attached to a sewing machine with a bobbin thread stored therein and supplies the bobbin thread when sewing an object to be sewn. The bobbin is composed of a bobbin body having a central guide shaft, a fixed flange portion fixed to an end of the central guide shaft, and a movable flange portion movably held on the central guide shaft. The lower thread is housed between the fixed flange and the movable flange, and the movable flange can approach the fixed flange as the lower thread is consumed.

The detection member presses the movable flange in the bobbin in conjunction with the operation of the thread trimming device as the thread trimming operation is performed, and detects the remaining amount of bobbin thread accommodated between the fixed flange and the movable flange. be. The sensing member is configured to be held at a position apart from the movable flange portion by the acting force of the biasing member except when the thread cutting device performs a thread cutting operation.

In addition to detecting the amount of movement of the sensing means, it is possible to send the amount of movement of the sensing member to a control section, which will be described later.
Furthermore, the amount of movement of the detection member can be sent as a signal. As the sensing means, a sensing member having a magnetic sensor and a sensing circuit associated with the magnetic sensor can be used. As the magnetic sensor, a Hall element or other known ones can be used as they are.

The control unit cuts off the initial value of the amount of movement of the detection unit sent from the sensing member, and compares the value of the amount of movement of the detection member after a predetermined time period has elapsed for the thread cutting operation with a predetermined value input in advance; Only when the amount of movement of the detection member is equal to or greater than a set value, an alarm signal is issued to an alarm device, which will be described later. The control section has delay means and comparison means. The delay means cuts the amount of movement when the sensing member impulsively presses the movable flange portion at the start of the thread cutting operation. The delay start time of the delay means can be at the start of the thread cutting operation or when the sensing member reaches a certain point, for example when the movable flange portion is pressed. Experimentally, the delay time is from several milliseconds to more than ten milliseconds, from when the sensing member impulsively presses the movable flange portion to when the impulsive pressure disappears. The comparison means compares the amount of movement of the detection member sent from the detection member with the set value.
It is preferable that the set value allows the time to be adjusted arbitrarily. For example, the comparison means emits a signal when the amount of movement is greater than a set value. A microcomputer can be used as this control section.

The alarm device operates upon receiving a signal from the control unit.
It is a warning. As the alarm of the alarm device, one that issues an alarm by sound, one that issues an alarm by lighting, blinking of a light, etc. can be used.

The detection member can have a permanent magnet fixed at one end and a detection section connected to the thread cutting device at the other end so as to be interlocked with the operation of the thread cutting device in accordance with the thread cutting operation.

(Function) According to the bobbin thread remaining amount detection device of the present invention, the movable flange portion of the bobbin is pressed in conjunction with the operation of the thread cutting device accompanying the thread cutting operation. After a certain period of time has elapsed after the thread cutting operation was started, the control unit compares the amount of movement when the movable flange section is in a steady state of pressure after being initially impulsively pressed with the set value, and determines the set value. Activate the alarm device when the limit is exceeded. The alarm device then generates an alarm.

(Example) Examples of the bobbin thread remaining amount detection device of the sewing machine of the present invention are shown in Figs. 1, 2, 3, 4, 5, and 6.
This will be explained based on the diagram.

The bobbin thread remaining amount detection device of the sewing machine according to the embodiment includes a bobbin 1, a detection member 2, a detection member 3, a control section 4, and an alarm device 5 as components.

The bobbin 1 is composed of a bobbin body 10 having a central guide shaft 101, a fixed flange portion 11 fixed to an end of the central guide shaft 101, and a movable flange portion 12 movably held on the central guide shaft 101. A bobbin thread 13 is accommodated between the portion 11 and the movable flange portion 12.

The detection member 2 presses the movable flange portion 12 of the bobbin 1 in conjunction with the operation of a thread cutting device (not shown in the figures) to detect the amount of remaining lower thread 13 in the bobbin 1. The detection member 2 comprises a detection portion 23 having a permanent magnet 21 fixed to one end and a support shaft 22 rotatably held at the other end, a detection arm 24 having a pressing portion 241 connected to the detection portion 23 and at the other end pressing the movable flange portion 12 of the bobbin 1, and an operating arm 26 connected to the other end of the detection portion 23 and having abutting against an operating lever 25 connected to the thread cutting device.
A coil spring 22 constantly biases the operating arm 26 in a pressing direction against the operating lever 25 that is linked to the thread cutting device.
It is composed of 7.

The sensing member 3 has a magnetic sensor 31 fixed on the base 30. As the magnetic sensor 31, a Hall element that senses the magnetism of the permanent magnet 21 fixed to the detection section 23 and generates a voltage can be used. The magnetic sensor 31 includes an electric circuit 32. This electric circuit 32 is connected to a control section 4, which will be described later.

The control unit 4 compares the amount of movement of the detection member 2 sent from the sensing member 3 after a predetermined time of operation of the thread cutting operation with a preset value, and when the amount of movement of the detection member 2 exceeds the set value, It generates an alarm signal and sends the alarm signal to an alarm device 5, which will be described later. The control unit 4 of this embodiment is composed of a microcomputer, and includes a comparison means for determining whether or not the amount of movement is greater than or equal to a set value, and when the comparison means determines that the amount of movement is greater than or equal to the set value, the amount of movement at that time is 10 mm. It has a delay means for determining whether or not more than one second has elapsed.
(In addition, as a modification of the control unit 4 of this embodiment, the control unit 4 counts the signals sent from the sensing member 3, and sends an alarm signal to the alarm device 5 when 10 milliseconds or more elapse. ) The alarm device 5 operates based on the alarm signal generated by the control section 4 and generates an alarm. Specifically, as the alarm device 5, an alarm sound generator 51 and a warning light 52 are used.

According to the embodiment configured as described above, the bobbin thread 13 housed in the bobbin 1 is gradually consumed as the sewing machine sews the cloth or the like to be sewn. Further, each time the sewing machine finishes sewing work, a thread cutting operation is performed by the thread cutting device, and the bobbin thread 13 is also cut at the sewing end position in preparation for the next sewing work. The actuating lever 25 actuates the actuating arm 26 during the thread cutting operation of the thread cutting device. This operation causes the detection unit 23 and detection arm 24 to operate. Further, the pressing portion 241 at the tip of the detection arm 24 presses the movable flange portion 12 of the bobbin 1 as shown in FIG. At the same time, the detection section 23 also moves toward the sensing member 3. In addition, as shown in FIG. 3, when the remaining amount of the bobbin thread 13 accommodated in the bobbin 1 is large, the amount of movement of the pressing part 241 of the detection arm 24 that presses the movable flange part 12 is also small, and the permanent magnet 2
The amount of approach of the first sensing member 3 to the magnetic sensor 31 is also small, resulting in the movement shown by the solid line shown in FIG. 5, and the sensing member 3 does not reach the detection position. and the control section 4 is the fourth
Make a judgment according to the flowchart shown in the figure and do not generate an alarm signal. Therefore, the alarm device 5 is not activated.

Furthermore, even if the detection arm 24 forcibly presses the movable flange portion 12 to a position where the remaining amount of bobbin thread 13 becomes small before the remaining amount of bobbin thread 13 in the bobbin 1 becomes small, the actual Since the remaining amount of bobbin thread is not small, the time during which the pressing portion 241 of the sensing arm 24 of the sensing member 2 presses the movable flange portion 12 is extremely short, and the permanent magnet 21 of the sensing portion 23 is as shown in FIG. The movement is as shown by the solid line and reaches the detection position of the sensing member 3, but the time for the sensing member 3 to act on the magnetic sensor 31 is less than 10 milliseconds.
In this case, movement amount detection data from the sensing member 3 that senses the magnetic field due to the positional movement of the permanent magnet 21 is sent to the control unit 4 for determination. In addition, the control unit 4 cuts off the initial value of the movement amount of the detection member 2 sent from the sensing member 3, and outputs the value of the movement amount after a certain period of time has passed for the thread trimming operation, and the setting value inputted to the control unit 4 in advance. , and detects that the amount of movement of the detection member 2 is less than the set value, and the control section 4 makes a judgment according to the flowchart shown in FIG. 4 and does not generate an alarm signal. Therefore, the alarm device 5 is not activated and no false alarm is generated.

Moreover, when the pressing part 241 at the tip of the detection arm 24 presses the movable flange part 12, if the remaining amount of the bobbin thread 13 in the bobbin 1 is actually small as shown in FIG. The amount of movement of the detection arm 24 increases. That is, the permanent magnet 21 moves as shown in the chain line in FIG. 6 and reaches the detection position of the sensing member 3, and the time for the permanent magnet 21 to act on the magnetic sensor 31 of the sensing member 3 is 50 milliseconds. In addition, the magnetic sensor 31 of the sensing member 3 captures the positional movement of the detection unit 23 and the permanent magnet 21 as the action time of the magnetic field of the permanent magnet 21, and this information is sent to the control unit 4. In addition, the control unit 4 cuts the initial value of the amount of movement of the sensing member 2 sent from the sensing member 3, and calculates the value of the amount of movement after a certain period of operation time of the thread cutting operation has elapsed;
Compare with the set value input in advance. In this case, the amount of movement of the detection member 2 is greater than or equal to the set value. This satisfies the condition that the amount of movement of the detection section 23 of the detection member 2 sent to the control section 4 is greater than or equal to the set value inputted in advance to the control section 4 . Therefore, in this case, the control section 4 makes a judgment according to the flowchart shown in FIG. 4 and generates an alarm signal. This causes the alarm device 5 to operate and issue an alarm.

[Effect of the invention] According to the bobbin thread remaining amount detection device of the sewing machine of the present invention,
The remaining amount of bobbin thread stored between the fixed flange and the movable flange of the bobbin is maintained by pressing the movable flange in conjunction with the thread trimming operation of the thread trimming device and keeping the thread trimming operation constant. After a period of time, the control unit, which has been inputted with the set value of the detection member movement amount in advance, compares the amount of movement of the detection member that detects the remaining amount of bobbin thread with the actual amount of movement of the detection member, and calculates the actual amount of movement of the detection member. An alarm signal can be generated only when the amount is greater than or equal to a set amount.

Therefore, the alarm device will not be erroneously activated only by the amount by which the movable flange portion of the bobbin is pressed by the detection member before the amount of bobbin thread remaining in the bobbin becomes small. That is, according to the configuration of the present invention, a reliable alarm state can be obtained only when the remaining amount of bobbin thread becomes small. Furthermore, even if the detecting member moves beyond the normal pressing position even though there is a large amount of bobbin thread remaining, the control section cuts off the initial value of the moving amount of the detecting member, and after a certain period of time has elapsed, Since the value of the movement amount is compared with data input in advance and the alarm is not issued, it is possible to prevent false alarms from occurring.

According to the configuration of the present invention, it is possible to reliably detect when the amount of bobbin thread remaining is small, so there is no need to move on to the next sewing operation with a small amount of bobbin thread remaining, as was the case in the past. It is possible to eliminate problems such as the bobbin thread ending in the middle of the sewing work and getting tangled, or sewing only the upper thread.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the main parts of the present invention. Figures 2 and 3 show the state in which the detection member detects the remaining amount of bobbin thread 13 in the bobbin 1. Figure 2 shows a case where there is a large amount of bobbin thread remaining, and Figure 3 shows the lower This indicates a state where there are few threads. FIG. 4 is a flowchart showing the operating state according to the embodiment of the present invention. 5 and 6 are explanatory diagrams showing the movement of a magnet fixed to a detection member that detects the remaining amount of bobbin thread, and the detection position of the detection member that detects the magnetic field of the magnet,
FIG. 5 shows a non-detection state, and FIG. 6 shows a detection state. FIG. 7 is a perspective view showing a conventional configuration. 1...Bobbin, 10...Bobbin body, 11...
Fixed flange part, 12...Movable flange part, 10
DESCRIPTION OF SYMBOLS 1...Central guide shaft, 2...Detection member, 21...Permanent magnet, 23...Detection part, 24...Detection arm,
26... Actuation arm, 241... Pressing part, 3...
Sensing member, 31... Magnetic sensor, 4... Control unit, 5... Alarm device.

Claims (1)

[Claims for Utility Model Registration] (1) A bobbin body having a central guide shaft, a fixed flange fixed to an end of the central guide shaft, and a movable flange movably held to the central guide shaft. a bobbin that stores the bobbin thread between the fixed flange section and the movable flange section; A sensing member that detects the amount of bobbin thread remaining; a sensing means that activates and issues a signal when the amount of movement of the sensing member exceeds a predetermined value; and a control unit that issues a signal when the signal from the sensing means continues for a predetermined time or more. A bobbin thread remaining amount detection device for a sewing machine, comprising: an alarm device that issues an alarm when receiving a signal from the control section. (2) The detection member has a permanent magnet fixed at one end and a detection section connected to the thread cutting device so as to be interlocked with the operation of the thread cutting device at the other end. The bobbin thread remaining amount detection device for the sewing machine according to item 1. (3) The bobbin thread remaining amount detection device for a sewing machine according to claim 1, wherein the sensing means includes a magnetic sensor that senses a permanent magnet that is integrally interlocked with the sensing member.