JPH06190176A - Bobbin thread supply structure of sewing machine - Google Patents

Abstract

PURPOSE:To constitute the structure so that shortage of a bobbin thread is not caused, and also, rejection of the bobbin can be suppressed to the minimum. CONSTITUTION:A sheet body 4 to be detected, having bright and dark sections is stuck to the outside surface 3 of a collar 2 of a bobbin 1. By a sensor 5, brightness and darkness of the sheet body 4 to be detected are detected. Based on brightness and darkness of the sheet body 4 to be detected, a removing speed of the bobbin 1 is counted by a counting means 6. The number of turns of a bobbin thread 7 wound round to the bobbin 1 in advance is stored in a storage means 8. The revolving speed of the bobbin 1 counted by the counting means 6 and the number of turns of the bobbin thread 7 stored in the storage means 8 are compared by a comparing means 9, and the remaining quantity of the bobbin thread 7 of the bobbin 1 is calculated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lower thread supplying structure for a sewing machine.

[0002]

2. Description of the Related Art When sewing a sewing machine using a sewing machine,
If the bobbin thread is insufficient, the sewn product becomes defective, and if the bobbin thread is in a large amount, it becomes useless. Therefore, the bobbin thread supply structure needs to detect the remaining amount of the bobbin thread.

However, conventionally, a bobbin around which a bobbin thread is wound is provided with an electric contact or the like, and when the remaining amount of the bobbin thread approaches the end, the electric contact is turned on or off, The remaining amount of thread was detected. In addition, holes and recesses are provided on the bobbin,
A small magnet is embedded in this, and the magnetic sensor detects this small magnet to detect the remaining amount of the lower thread.

[0004]

In the above-mentioned conventional method, the bobbin, which is a consumable item, must be processed, which is troublesome and costly. Moreover, there are a plurality of types of bobbins. In some cases, the above method cannot be performed.

Therefore, in the present invention, the remaining amount of the lower thread can be reliably detected, and the currently used bobbin, bobbin case, outer hook, and inner hook can be used as they are. An object is to provide a yarn supply structure.

[0006]

In order to achieve the above-mentioned object, a bobbin thread supplying structure of a sewing machine according to the present invention is attached to the outer surface of a collar of a bobbin, and a detected sheet body having bright and dark sections. A sensor for detecting the brightness of the detected sheet body, and a counting means for counting the number of rotations of the bobbin based on the brightness of the detected sheet body detected by the sensor,
The storage means for storing the number of windings of the bobbin thread wound on the bobbin in advance, the rotation number of the bobbin counted by the counting means and the number of windings of the bobbin thread stored in the storage means are compared to determine And a comparison means for calculating the remaining amount of yarn.

[0007]

If the sheet to be detected is attached to the outer surface of the collar of the bobbin and the sewing machine is driven, the bobbin rotates with the driving of the sewing machine and the bobbin thread is successively fed from the bobbin.

At this time, the sensor detects the brightness of the sheet to be detected, and the number of rotations of the bobbin is counted by the counting means in accordance with this detection.

The storage means stores the number of windings of the bobbin thread wound on the bobbin in advance, and the comparison means compares the number of rotations counted by the counting means with the number of windings stored in the storage means. To be done.

That is, when the bobbin rotates in the direction opposite to the winding direction by the stored number of windings, the bobbin is completely free of the bobbin thread. Further, the supply amount of the yarn when the bobbin makes one rotation is known in advance.

Therefore, the remaining amount of the lower thread can be calculated by comparing the counted number of revolutions with the stored number of turns.

[0012]

The present invention will be described in detail below with reference to the drawings illustrating the embodiments.

FIG. 1 is a block diagram of a bobbin thread supplying structure of a sewing machine according to the present invention. This structure has an outer surface 3 of a collar 2 of a bobbin 1.
To-be-detected sheet body 4 attached to the
Sensor 5 for detecting the light and darkness of the bobbin 1, counting means 6 for counting the number of rotations of the bobbin 1 based on the lightness and darkness of the detected sheet body 4 detected by the sensor 5, and the bobbin thread 7 wound on the bobbin 1 in advance. The storage means 8 stores the number of turns, and the comparison means 9 compares the number of revolutions of the bobbin 1 counted by the counting means 6 with the number of turns stored in the storage means 8.

As shown in FIG. 5, the bobbin 1 has a body portion 10 and the above-mentioned collars 2, which are continuously provided at both ends of the body portion 10.
It consists of 2 and is installed in the bobbin case 11.

The bobbin case 11 includes a peripheral wall 11a, an end wall 11b and a central cylindrical portion 11c, and the central cylindrical portion 11c is the bobbin 1.
It is inserted in the body part 10 of the.

The bobbin case 11 is installed in the inner cover 12. In this case, the shaft portion 12a of the inner cutter 12 is the bobbin case.
The central cylindrical portion 11c of 11 is fitted.

The inner hook 12 is attached to the outer hook 13, and the outer hook 13 is attached.
A shaft 14 arranged on the back surface 21 side of the sewing machine base 20 shown in FIG.

Further, the bobbin case 11 is formed with a notch 15 as shown in FIGS. 3 and 6.

However, the sheet body 4 to be detected has bright and dark sections as shown in FIG.

That is, the detected sheet body 4 is made of a thin circular body having a central hole corresponding to the collar 2 of the bobbin 1, and has a bright portion 16 of white or the like and a dark portion of black or the like on its front surface.
17 is drawn to form bright and dark sections, an adhesive or the like is applied to the back surface of the section, and the section is attached to the outer surface 3 of the collar 2 of the bobbin 1.

Although the dark portion 17 is fan-shaped in FIG. 1, it may be a semi-circle as shown in A of FIG. 7 or a straight line in the radial direction as shown in B of FIG. Good.

That is, it is sufficient that the sensor 5 can detect the bright portion 16 and the dark portion 17, and the counting means 6 can count the number of rotations of the bobbin 1.

As the sensor 5, for example, a photoelectric sensor or the like is used, and as shown in FIG.
The light emitted toward the notch 15 (see FIGS. 3 and 6) and reflected by the detected sheet body 4 of the bobbin 1 in the bobbin case 11 is received.

Therefore, when the dark portion 17 is illuminated, no light is reflected, and it is possible to detect that the dark portion 17 is illuminated.

That is, if the bright portion 16 is detected after the dark portion 17 is detected and then the dark portion 17 is detected again, it means that the bobbin 1 has made one rotation, and the counting means 6 counts the number of rotations. Is.

As shown in FIGS. 2 and 3, the sensor 5 is a swing arm disposed on the back surface 21 side of the sewing machine base 20.
Mounted on 18 tips.

The swing arm 18 is fixed to a rotary shaft 19 arranged in parallel with the shaft 14, and swings as shown by arrows A and B by the rotation of the rotary shaft 19.

That is, a holding plate 22 is fixed to the back surface 21 of the sewing machine base 20, a drive motor 23 is attached to the holding plate 22, a small gear 24 is attached to the output shaft 23a of the motor 23, and a rotary shaft 19 is attached. Is equipped with a large gear 25 that meshes with the small gear 24,
When is driven, the large gear 25 meshing with the small gear 24 rotates, thereby rotating the rotating shaft 19.

A pivot member 27 having bearings 26, 26 is attached to the holding plate 22 to smoothly rotate the rotary shaft 19.

A stopper member 28 is attached to the base end of the rotary shaft 19, and the stopper member 28 regulates the swing of the swing arm 18.

That is, as shown in FIGS. 2 and 4, the stopper member 28 includes an arm 28a fixed to the base end of the rotary shaft 19,
A rod 28b protruding from the tip of the arm 28a, and the rod 28b holds the holding plate 22 as shown by the solid line in FIG.
By abutting against, the swing in the direction of arrow C (that is, the swing of the swing arm 18 in the direction of arrow B) is restricted.

Further, as shown in FIG.
A holder 30 for holding the cord 29 of the sensor 5 is attached,
A cord 29 is arranged along the rotary shaft 19 and the swing arm 18.

Therefore, as shown in FIG. 4, the stopper member
When 28 is in contact with the holding plate 22, as shown in FIG.
The sensor 5 faces the notch 15 of the bobbin case 11.

Further, the rotary shaft 19 rotates and the swing arm 18 swings in the direction of arrow A as shown in FIG. 6 (that is, the stopper member 28 swings in the direction of arrow D as shown in FIG. 4). Then, the swing arm 18 can be retracted from the bobbin 1.

That is, in the state shown in FIG. 6, the bobbin 1 can be easily replaced and the workability is improved.

In this case, a brush 31 is provided below the bobbin 1 as shown by the phantom lines in FIGS. 2 and 3, and when the sensor 5 is retracted as shown in FIG. The head 5a can be cleaned.

That is, in the environment where the sewing machine is used,
The lint, dust, oil, etc., of the head 5 of the sensor 5 shown in FIG.
This is because there is a risk of adhesion to a, and if it does, the sensor 5 malfunctions and accurate detection cannot be performed.

The brush 31 is, for example, as shown in FIG.
It is held by a holding frame body 32 protruding from the holding plate 22.

Further, as a cleaning of the head 5a of the sensor 5, as shown in FIG. 8, it is also preferable to blow air to the head 5a.

In this case, the air blowing nozzle 33 may be arranged near the retracted position of the sensor 5.

In FIG. 2 and the like, 34 is the back surface of the sewing machine base 20.
It is an inner stopper that can be attached to the 21 side.

Next, a sewing operation using the sewing machine having the lower thread supply structure of the sewing machine constructed as described above will be described.

First, the sheet body to be detected 4 is attached to the outer surface 3 of the collar 2 of the bobbin 1, and the bobbin thread 7 is wound around the bobbin 1.

At this time, the number of threads of the lower thread 7 is counted, and the counted winding number is stored in the storage means 8.

The sensor 5 counts the number of turns.
It may be performed by detecting the lightness and darkness of the detected sheet body 4 by a photoelectric sensor similar to the above.

Next, as shown in FIG. 5, the bobbin 1 around which the bobbin thread 7 is wound is mounted on the bobbin case 11 and the bobbin case 11 is mounted on the inner shell 12 and the inner shell 12 is removed. Attach to Kama 13.

At this time, the swing arm 18 is in the retracted state as shown in FIG. 6, and after the mounting is completed, the swing arm 18 is swung as shown in FIG.
Face the notch 15 of the bobbin 1.

By driving the sewing machine,
The bobbin thread 7 is pulled, the bobbin 1 rotates about its axis, and the bobbin thread 7 is successively paid out from the bobbin 1.

At this time, the light and darkness of the detected sheet body 4 of the bobbin 1 is detected by the sensor 5, and the counting means 6 is based on this.
The rotation speed of bobbin 1 is counted.

While the sewing machine is being driven, the number of revolutions counted by the counting means 6 and the number of windings of the lower thread 7 stored in the storage means 8 are compared by the comparison means 9.

That is, from the total number of rotations (number of threads) of the bobbin 1 when the bobbin thread 7 is wound around the bobbin 1, the bobbin 1 by sewing is obtained.
The remaining amount of the bobbin thread 7 can be easily calculated by subtracting the number of revolutions.

When the remaining amount reaches a predetermined amount (for example, 2 m), the display means 35 (see FIG. 1) displays that fact.

The display means 35 means, for example, an LED that lights up or a sound is emitted from a buzzer.

Therefore, when the remaining amount of the bobbin thread 7 reaches a predetermined amount, the driving of the sewing machine can be stopped and the bobbin thread does not run short.

In addition, it is possible to minimize the waste of the lower thread 7, which is economically advantageous. When the driving of the sewing machine cannot be stopped midway due to sewing, the remaining amount of the bobbin thread 7 is set within the range for one step, and even after the remaining amount is displayed on the display means 35. Then, the sewing can be continuously performed and completed. Even in this case, the waste of the lower thread 7 can be minimized.

Therefore, according to the above-described embodiment, when the bobbin 1 is replaced, the swing arm 18 can be swung to retract the sensor 5 as shown in FIG. The bobbin 1 can be easily replaced, and the workability is excellent.

Moreover, when the sensor 5 is retracted, the head 5a of the sensor 5 is cleaned by the brush 31 or the air blowing, and malfunctions due to the adhesion of lint, dust, oil, etc. are eliminated, and accurate detection is possible. Therefore, the remaining amount can be always detected in a stable state. In order to prevent damage to the head itself, the head 5a of the sensor 5 may be cleaned if the cover is integrally provided.

[0058]

Since the present invention is configured as described above, it has the following effects.

The remaining amount of the bobbin thread 7 can be surely discriminated, the bobbin thread of the sewn product does not become insufficient, defective products are not generated, and a sewn product of high quality can always be provided.

The waste of the lower thread 7 can be minimized and waste is eliminated.

The detection target sheet body 4 may be attached to the outer periphery 3 of the collar 2 of the bobbin 1, and the bobbin 1 currently used,
The bobbin case 11, the outer cutter 13, the inner cutter 12, etc. can be used as they are without any additional processing, and they have excellent workability, and
There is an advantage that the cost is not high.

The set value of the remaining amount of the lower thread 7 can be freely changed according to the sewn product or the like, which is convenient.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a bottom view of a main part.

FIG. 3 is a side view of a main part.

FIG. 4 is a side view of a main part.

FIG. 5 is an enlarged sectional view of an essential part.

FIG. 6 is a side view of a main part.

FIG. 7 is a front view showing a modified example of the detected sheet body.

FIG. 8 is a bottom view of a main part showing a modified example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 bobbin 2 collar 3 outer surface 4 detected sheet body 5 sensor 6 counting means 7 bobbin thread 8 storage means 9 comparing means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazumasa Fujikawa 10 Nishikyogokutsutsumimachi, Ukyo-ku, Kyoto City Nidec Corporation FA Development Center

Claims (1)

[Claims] 1. A detection target sheet body 4 which is attached to an outer surface 3 of a collar 2 of a bobbin 1 and has a bright and dark section, a sensor 5 for detecting the brightness of the detection target sheet body 4, and the sensor 5. Counting means 6 for counting the number of rotations of the bobbin 1 based on the lightness and darkness of the detected sheet body 4 detected by the above, and a storage means 8 for storing the winding number of the bobbin thread 7 wound in advance on the bobbin 1.
Comparing means 9 for comparing the number of revolutions of the bobbin 1 counted by the counting means 6 with the number of windings of the bobbin thread 7 stored in the storage means 8 to calculate the remaining amount of the bobbin thread 7 of the bobbin 1. A bobbin thread supply structure for a sewing machine, characterized by comprising: