JPH0568766A - Residual bobbin thread quantity detecting device for sewing machine - Google Patents

Abstract

(57) [Summary] [Purpose] A bobbin thread for a sewing machine capable of displaying in multiple stages the change in the bobbin thread remaining amount from the state in which the bobbin thread is wound around the bobbin to the maximum. To provide a remaining amount detecting device. A detection rod holder 63 is rotatably connected to the tip of an arm 57 that is rotated by a rotary solenoid 59, and a detection rod 53 with a head 53a can slide up and down from the holder 63. Supported by the detection rod 53
A magnet holder 67 having a permanent magnet 65 is fixed to
A coil spring 69 is wound between the detection rod holder 63 and the magnet holder 67. The detection rod 53 is brought into contact with the shaft portion of the empty bobbin 45 by the solenoid 59, and the position at that time is stored. Next, a bobbin around which the lower thread is wound is attached and brought into contact with the lower thread, and the remaining amount is displayed on a 100% scale.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lower thread remaining amount detecting device for a sewing machine which detects the remaining amount of lower thread wound around a bobbin,
More specifically, the present invention relates to a lower thread remaining amount detecting device capable of notifying an operator of a change in the lower thread remaining amount.

[0002]

2. Description of the Related Art Conventionally, the lower thread remaining amount of a sewing machine is detected,
2. Description of the Related Art A bobbin thread remaining amount detecting device for a sewing machine is known that informs an operator of a decrease in the bobbin thread remaining amount before the bobbin thread runs out. For example, Japanese Patent Publication No. 61-43075 and Japanese Utility Model Publication No. 63-136591.
The publication describes a device for detecting the remaining amount of the lower thread by inserting a detection rod into the bobbin when the rotation of the outer hook is stopped and bringing the tip of the detection rod into contact with the lower thread wound around the bobbin. ing.
This device warns the operator of the decrease in the remaining amount of the bobbin thread when the remaining amount of the bobbin thread decreases below a predetermined value and the insertion amount of the detection rod exceeds the predetermined amount.

[0003]

However, this type of bobbin thread remaining amount detecting apparatus keeps the operator from changing the bobbin thread remaining amount until the bobbin thread remaining amount falls below a predetermined amount and an alarm is issued. No notification at all. For this reason, the operator cannot estimate when the bobbin thread will run out, and he must always sew while paying attention to the warning. Further, since the alarm is issued without any warning, the operator may overlook it, and in this case, the bobbin thread may be lost during sewing. As a result, only needle holes are left in the material, and the product value of the sewn product is greatly reduced.

Therefore, the present invention has been made for the purpose of providing a bobbin thread remaining amount detecting device for a sewing machine capable of always accurately grasping a change in the bobbin thread remaining amount.

[0005]

SUMMARY OF THE INVENTION A bobbin thread remaining amount detecting device of a sewing machine according to the present invention made to achieve the above object continuously delivers a bobbin thread remaining amount wound around a bobbin provided in a hook of a sewing machine. From the state in which the bobbin thread is maximally wound on the bobbin to the state in which the bobbin thread has completely disappeared, based on the bobbin thread remaining amount detecting means that is detected automatically and the detection result of the bobbin thread remaining amount detecting means. It is characterized in that it is provided with a display means for displaying a change in the remaining amount of the lower thread in a plurality of stages.

[0006]

In the present invention thus constructed, the bobbin thread remaining amount detecting means continuously detects the bobbin thread remaining amount wound on the bobbin, so that the bobbin is wound maximally on the bobbin. It is possible to continuously detect a change in the remaining amount of the bobbin thread from the state where the bobbin thread completely disappears.

On the other hand, the display means divides and displays the change of the lower thread remaining amount based on the detection result of the lower thread remaining amount detecting means in a number of stages. You can always know exactly if it belongs to.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 is a front view showing the configuration of the lower thread remaining amount detecting device according to the embodiment. However, in FIG. 1, a detection rod guide 55, which will be described later, is drawn by cutting along the line AA in FIG.

As is well known, in a bed of a sewing machine, there is provided a hook portion 3 for catching an upper thread in cooperation with a needle (not shown) which can move up and down to form a lock stitch on a work cloth. Figure 1
As shown in FIG. 3, the shuttle 3 is provided with an outer shuttle 31 that is rotatable in synchronization with the vertical movement of the needle, and an inner shuttle 33 is held in the outer shuttle 31 in a stationary state. Further, a bobbin case 39 having a hole 37 formed in a lower side surface is detachably positioned and mounted in the housing portion 35 of the inner hook 33. Further, a bobbin 45 around which a lower thread 43 is wound is detachably and rotatably mounted on a hollow support shaft 41 protruding from the inner wall of the bobbin case 39. When the outer pot 31 is stopped, the outer pot 3 is placed below the hole 37.
The stop position of the outer hook 31 is determined in advance so that no part of 1 is provided.

On the other hand, a detector 5 is provided below the shuttle 3. A detection rod guide 55 that vertically slidably supports a detection rod 53 is vertically fixed to a fixing plate 51 that fixes the detection unit 5 to the sewing machine body, and the detection rod 53 is driven via an arm 57. Rotary solenoid 59 and Hall element 61 that generates a voltage proportional to the strength of the magnetic field
Is fixed. The detection rod holder 6 is attached to the tip of the arm 57.
3 is rotatably connected, and the detection rod 53 is slidably penetrated through the detection rod holder 63. In addition, the detection rod 53
A magnet holder 67 having a permanent magnet 65 fixed to the tip thereof is fixed to the center of the magnet holder 67 and the detection rod holder 6
A coil spring 69 is attached between the coil 3 and the shaft 3 around the detection rod 53. The edge of the detection rod holder 63 opposite to the coil spring 69 contacts the lower end head portion 53a of the detection rod 53,
The detection rod holder 63 is held against the biasing force of the coil spring 69. Further, as shown in the bottom view of FIG. 2, since the hall element 61 is provided so as to face the permanent magnet 65, the generated voltage of the hall element 61 changes corresponding to the position of the detection rod 53.

In the bobbin thread remaining amount detecting device of the present embodiment having the above-mentioned structure, when the outer hook 31 is stopped, the hole 37 is formed into the hook 3.
Exposed on the underside of. Subsequently, when the rotary solenoid 59 is excited, the arm 57 rotates counterclockwise to detect the detection rod holder 63.
Moves upwards. Then, the force is transmitted via the coil spring 69, and the magnet holder 67 and the detection rod 53 fixed thereto move upward.

As a result, the detection rod 53 is inserted into the bobbin case 39 through the hole 37 as shown by the chain double-dashed line in the figure, and the upper end of the detection rod 53 is wound on the bobbin 45. Abut 43. Therefore, if the Hall element 61 detects the position of the detection rod 53 at this time, the remaining amount of the lower thread 43 can be obtained. Further, since the coil spring 69 is interposed between the detection rod holder 63 and the magnet holder 67, the impact applied when the detection rod 53 contacts the lower thread 43 can be mitigated.

Next, when the rotary solenoid 59 is demagnetized, the arm 57 returns to its original position by the action of a spring (not shown) built into the rotary solenoid 59. Then, along with this, the detection rod 53 also moves downward and is housed in the detection rod guide 55. On the other hand, the sewing machine of this embodiment is provided with a display panel 7 as shown in FIG. A bobbin thread remaining amount indicator 71 provided at the center of the display panel 7 is composed of three 7-segment displays and displays the bobbin thread remaining amount on a 100% scale. Next to the bobbin thread remaining amount indicator 71, a set level indicator 73 composed of one 7-segment display is provided. The set level indicator 73 displays the set level set based on the lower bobbin thread remaining amount to be alarmed. Incidentally, a correspondence relation is given between a bobbin thread remaining amount to be alarmed and a set level by a predetermined table (not shown).

Below the set level indicator 73, a set level up key 75 for increasing the set level and a set level down key 77 for decreasing the set level are provided. Further, on the display panel 7, a bobbin thread warning lamp 79 that lights up when the bobbin thread remaining amount falls below a set level, and a buzzer 81 that also sounds an alarm when the bobbin thread remaining amount falls below the set level. , The reset key 83 for stopping the buzzer 81, and the Hall element 6 when the upper end of the detection rod 53 comes into contact with the bobbin winding surface.
A 0% setting key 85 for storing the generated voltage of 1 is provided for each.

Next, the detecting section 5 and the display panel 7 are connected to a control circuit 9 as shown in FIG. 4, whereby the lower bobbin thread remaining amount is detected and an alarm is issued. The control circuit 9 stores an I / O port 91 for inputting / outputting signals to / from an external device, a central processing unit (CPU) 93 for performing various arithmetic processes, and various programs used for a bobbin thread remaining amount detecting process described later. Read-only memory (R
OM) 95, random access memory (RAM) 97 for temporarily storing various data, and I / O port 9
1, a CPU 93, a ROM 95, and a RAM 97 are electrically connected to each other, and a bus line 99 for transmitting and receiving signals is a well-known electronic control circuit.

On the I / O port 91, the setting level up key 75 and the setting level down key 7 are displayed on the display panel 7.
7, the operation state of the reset key 83, and the 0% setting key 85 are input, and further, the output of the rotary encoder 103 that detects the rotation of the upper shaft of the sewing machine arm 101, the amplification circuit 105, and the A / D converter 107. The converted voltages generated by the Hall element 61 are input.

The I / O port 91 outputs drive signals to the lower thread remaining amount indicator 71, the set level indicator 73, the lower thread warning lamp 79, and the buzzer 81 of the display panel 7, and further the sewing machine arm. Motor 1 for driving the upper shaft of 101
Drive signals to the rotary solenoid 59 of the detector 11 and the detector 5 are output via the drive circuits 113 and 115, respectively.

Next, the bobbin thread remaining amount detection processing performed by the control circuit 9 thus configured will be described with reference to FIGS. 5 and 6. In the bobbin thread remaining amount detecting apparatus of this embodiment, before starting sewing, first, the empty bobbin 45 on which the bobbin thread 43 is not wound is attached to the hook portion 3, and the outer hook 31 is not rotated. The 0% setting key 85, the setting level up key 75, and the setting level down key 77 are operated to perform the predetermined processing described below before use.

When the 0% setting key 85 is operated, the control circuit 9 detects the stop position (phase) of the sewing machine main shaft from the detection signal of the rotary encoder 103, and the position is below the hole 37 of the bobbin case 39. Determines whether or not it is in a predetermined stop position where no portion of the outer pot 31 is provided. If not, the main shaft is rotated and the outer hook 31 is stopped at the predetermined stop position. This is because the main shaft is manually rotated before the 0% setting key 85 is operated, and the detection rod 53 has the hole 37.
This is to cope with the case where it is impossible to insert into.

Subsequently, the control circuit 9 operates the rotary solenoid 5
9 is excited to insert the detection rod 53 into the bobbin case 39 through the hole 37, and the tip of the detection rod 53 is brought into contact with the bobbin 45. At this time, the voltage generated by the Hall element 61 changes as shown in FIG. 5 according to the insertion amount of the detection rod 53.

That is, before the rotary solenoid 59 is excited, the detection rod 53 is arranged at the standby position A, and when the rotary solenoid 59 is excited, the tip of the detection rod 53 is moved to the bobbin 4.
5 is inserted up to the 0% position B where it abuts the bobbin winding surface. At this time, the voltage generated by the hall element 61 increases substantially in proportion to the insertion amount of the detection rod 53, and becomes the voltage VB at the 0% position B.
The control circuit 9 stores this voltage VB in the RAM 97 and uses it in the processing described later.

Then, when the 0% setting key 85 is released,
The control circuit 9 degausses the rotary solenoid to detect the detection rod 5
Return 3 to the standby position A. In the middle of this, the detection rod 53 passes through the retracted position C where the tip of the detection rod 53 intersects with the outer circumference of the rotation path of the outer pot 31. When the outer hook 31 rotates while the detection rod 53 has been inserted into the hook portion 3 beyond the retracted position C, the detection rod 5
3 and the outer hook 31 collide with each other and are damaged. Therefore, in the bobbin thread remaining amount detecting device of the present embodiment, the driving of the motor 111 is prohibited until the voltage generated by the hall element 61 becomes equal to or lower than the voltage VC corresponding to the retracted position C. Since the retracted position C is uniformly determined by the sewing machine, the corresponding voltage VC
Are stored in the ROM 95 in advance.

On the other hand, when the setting level up key 75 or the setting level down key 77 is operated, the setting level is changed sequentially. When the desired setting level is selected in this way, a voltage VD lower than the voltage VB by a predetermined amount corresponding to the setting level is calculated. Then, as will be described later, the control circuit 9 judges that when the generated voltage of the hall element 61 exceeds the voltage VD, the bobbin thread remaining amount to be alarmed is reached.

After performing such processing, the bobbin 45 having the lower thread 43 wound thereon is newly mounted on the shuttle portion 3, and the sewing operation is started. The control circuit 9 during the sewing operation constantly observes the detection signal of the rotary encoder 103, and when the upper shaft stops and the outer hook 31 stops, the following bobbin thread remaining amount detection processing is executed.
This bobbin thread remaining amount detection processing will be described below with reference to the flowchart of FIG.

When the process is started, the rotary solenoid 59 is first excited in S1. As described above, since the outer hook 31 is stopped at this time, the detection rod 53 is inserted into the bobbin case 39 through the hole 37, and the tip of the detection rod 53 is attached to the bobbin thread 43 wound around the bobbin 45. Abut.

Next, in S3, the generated voltage V of the Hall element 61 is
After reading H, it is determined in S5 whether or not the generated voltage VH is higher than the above-mentioned voltage VD corresponding to the set level. If the generated voltage VH is lower than the voltage VD, S1
At 0, the lower thread warning lamp 79 is turned off and the process proceeds to S7. On the other hand, when it is determined that the generated voltage VH is larger than the voltage VD and the lower bobbin thread remaining amount to be alarmed is reached, the lower thread warning lamp 79 is blinked in S9 and the buzzer 81 is driven to proceed to S7.

When the process proceeds to S7, the generated voltage VH is compared with the above-mentioned voltage VB corresponding to the 0% position B and the voltage VE corresponding to the state where the bobbin thread 43 is wound around the bobbin 45 to the maximum, The remaining amount is calculated on a 100% scale. Here, the size of the collar of the bobbin 45 is substantially standardized, and the insertion amount of the detection rod 53 when the tip of the detection rod 53 abuts the bobbin thread 43 wound around the bobbin 45 to the maximum is also determined by the sewing machine. Determine uniformly. Therefore, the voltage VE is also stored in the ROM 95 in advance like the voltage VC.

In S11, the bobbin thread remaining amount calculated in S7 is displayed on the bobbin thread remaining amount indicator 71, the rotary solenoid 59 is demagnetized in S13, and the process proceeds to S15. In S15, the generated voltage VH of the hall element 61 is newly read, and in the subsequent S17, it is determined whether or not the generated voltage VH read in S15 is lower than the voltage VC corresponding to the retracted position C. If the generated voltage VH is lower than the voltage VC, the process directly proceeds to S19. If the detection rod 53 has not yet passed the retracted position C and the generated voltage VH is higher than the voltage VC, the process proceeds to S15 again.

That is, at S13, the rotary solenoid 59
Is demagnetized, the detection rod 53 returns to the standby position A, but if the outer pot 31 rotates without the detection rod 53 returning to the retracted position C, the detection rod 53 collides with the outer pot 31 and is damaged. Resulting in. Therefore, in S15 and S17, the process waits until the detection rod 53 passes the retracted position C. When the detection rod 53 passes the retracted position C and moves to S19, the re-driving of the motor 111 is permitted and the process is ended.

As described above, in the bobbin thread remaining amount detecting apparatus of this embodiment, the bobbin thread remaining amount can be displayed on the 100% scale every time the motor 111 is stopped. You can grasp it accurately. Therefore, the operator can roughly predict when the bobbin thread will be depleted, and it will be possible to favorably prevent the bobbin thread from being depleted during sewing.

In the bobbin thread remaining amount detecting apparatus of this embodiment, when the bobbin thread remaining amount falls below the set level set by the set level up key 75 and the set level down key 77, the bobbin thread warning lamp 79 and the buzzer 81 are shown. Generate an alarm at. An optimum value can be selected for the set level according to the thickness of the thread and the like, and it is possible to more effectively prevent the lower thread from running out during sewing.

Further, in the bobbin thread remaining amount detecting apparatus of this embodiment, the voltage VB corresponding to the 0% position B is detected before the sewing is started, and the bobbin thread remaining amount is detected based on this. ,
It is possible to accurately detect the remaining amount of the lower thread near the 0% position B, which is particularly important when an alarm is issued. Although only the voltage VB is detected in this embodiment, the voltage VE corresponding to the state where the bobbin thread 43 is wound around the bobbin 45 at the maximum is also detected before the start of sewing, and this is used to detect the bobbin thread remaining amount. The amount may be calculated, and in this case, the lower thread remaining amount can be calculated more accurately. On the contrary, the voltage VB may be set in advance and stored in the ROM 95.

In this embodiment, the insertion amount of the detection rod 53 is detected by the hall element 61, but the insertion amount of the detection rod 53 is detected by using another displacement sensor such as a variable capacitor or a differential transformer. You can also do it. Further, in this embodiment, the lower thread remaining amount is detected from the insertion amount of the detection rod 53, but in addition to this, various types such as an optical detection device for irradiating the lower thread 43 with light to detect the lower thread remaining amount. The lower thread remaining amount detecting device can be applied.

Further, in the present embodiment, the bobbin thread remaining amount is displayed on the 100% scale, but various display methods such as visually displaying with a bar graph can be applied.

[0035]

As described in detail above, in the bobbin thread remaining amount detecting device of the present invention, the bobbin thread is completely wound around the bobbin by the display means, and the bobbin thread is completely removed. Since the change in the lower thread remaining amount up to is displayed in a divided manner in a number of stages, the operator can always accurately grasp the lower thread remaining amount. Therefore, the operator can predict when the bobbin thread will be depleted, and the bobbin thread can be prevented from being depleted during sewing.

[Brief description of drawings]

FIG. 1 is a front view showing a configuration of a lower thread remaining amount detecting device according to an embodiment.

FIG. 2 is a bottom view showing a configuration of a detection unit of the lower thread remaining amount detection device.

FIG. 3 is a front view showing a display panel of the lower thread remaining amount detecting device.

FIG. 4 is a block diagram schematically showing a configuration of the lower thread remaining amount detecting device.

FIG. 5 is an explanatory diagram showing the relationship between the insertion amount of a detection rod and the generated voltage of a Hall element.

FIG. 6 is a flowchart showing a bobbin thread remaining amount detection process performed by a control circuit.

[Explanation of symbols]

3 ... Hook part 5 ... Detection part
7 ... Display panel 9 ... Control circuit 31 ... Outer pot 3
7 ... hole 39 ... bobbin case 43 ... bobbin thread
45 ... Bobbin 53 ... Detection rod 59 ... Rotary solenoid
61 ... Hall element 65 ... Permanent magnet 71 ... Bobbin thread remaining amount indicator
73 ... Setting level indicator 75 ... Setting level up key 77 ... Setting level down key 79 ... Bottom thread warning light 81 ... Buzzer
85 ... 0% setting key

Claims (1)

[Claims] 1. A bobbin thread remaining amount detecting means for continuously detecting a bobbin thread remaining amount wound around a bobbin provided in a bobbin of a sewing machine, and the above-mentioned method based on a detection result of the bobbin thread remaining amount detecting means. The bobbin is provided with a display means for displaying a change in the remaining amount of the bobbin thread from a state in which the bobbin thread is maximally wound to a state in which the bobbin thread is completely removed, divided into a number of stages. A bobbin thread remaining amount detecting device of a characteristic sewing machine.