JPS58221981A - Automatic upper yarn supply apparatus of sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that detects the state of needle thread consumption for each stitch in stitch formation and automatically supplies needle thread in accordance with the amount of needle thread consumed.

The upper thread of the sewing machine is given a constant tension by the thread tension device during operation, but due to changes in the thread, type of fabric, sewing pattern, and sewing machine drive speed, the thread may be insufficiently fed out or may not be fed out too much. There is a phenomenon in which thread breakage or skipped stitches occur due to unstable thread tension. Conventionally, in order to adjust this, a spring was used to absorb the thread slack between the thread tension device and the thread spool.
Although cushioning materials have been provided, the above drawbacks have not been overcome.

On the other hand, Japanese Patent Application Laid-Open No. 53-79647 proposes a needle thread supply device for a sewing machine that solves the above-mentioned drawbacks by sequentially feeding out the necessary amount of needle thread for each stitch. In other words, in Japanese Patent Application Laid-open No. 53-79647, the amount of needle feed, the amount of needle vibration in zigzag stitching, the material thickness, etc. are detected, and based on these values, the upper part of one stitch is calculated from a predetermined calculation formula. The amount of thread consumed is calculated and the upper thread is supplied according to the amount.

However, in this case, once an error occurs between the calculation result and the actual amount of needle thread consumption during sewing for some reason, the error cannot be resolved and incorrect thread winding continues. However, if errors are accumulated, sewing becomes impossible.

The present invention has been researched in view of the above points, and includes a needle thread supply device that sequentially feeds out an amount of thread for each needle on the upper thread path of the sewing machine, and and a detection device for detecting excess or deficiency of the supply system amount with respect to the actual yarn consumption amount, and the supply system amount of the needle thread supply device is controlled in response to a detection signal from the detection device, To provide a needle thread supply device for a sewing machine that can immediately supply a corresponding amount of thread even if there is a variation in the amount of thread consumed during sewing, and can always obtain appropriate stitches.

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view of the main parts of a sewing machine in which the present invention device is attached to a sewing machine arm body shown by phantom lines. In FIG. 1, a base 2 is fixed to an arm body 1, and a detection device 3 and a needle thread supply device 4 are attached to the base 2. The detection device 3 consists of a make contact terminal 5 and a break contact terminal 6 fixed to a base 2 facing each other with an interval between them, a common terminal 7 fixed to the side thereof, and a central part supported by a support shaft 8. The detector 9 has a substantially dogleg shape, and its upper end is located between both contact terminals 5 and 6, and the common terminal 7 and detector A sensor spring 10 is stretched between the sensor spring 10 and the upper part of the sensor 9 to connect the common terminal and the detector 9, and the detector 9 is always kept in contact with the contact terminal 6 and extends diagonally downward. A tension pulley 1 is rotatably attached to the lower end of the detector 9.

Next, the needle thread supply device 4 will be described. Numeral 12 is a nockle smoker, which is fixed to the back surface of the base 2 adjacent to the lower part of the detector 9, with its rotation axis extending to the surface, and a motor pulley at the end. 13 is fixed, and the motor pulley 13
A guide roller plate 14 is pivotally connected to the base 2 at its center by a support shaft 15, and a guide roller 16 is rotatably attached to the end of the guide roller plate 14. Axial pin 1 protruding from the other end and the base 2 below it
A spring 18 is stretched between the guide roller 16 and the motor pulley 13 to press the guide roller 16 against the motor pulley 13 with a constant pressure. 19
, 210 are thread guides fixed to the base 2, and thread guide 1
Reference numeral 9 is provided below between the tension pulley 1 and the thread take-up 21, the thread guide 2o is provided on the side of the thread guide 13, and the base 2 is provided above the thread guide 20.
A solenoid device 22 that locks and releases the thread in response to an electric signal is fixed to the solenoid device 22. 23 indicates an upper thread, and the upper thread 23 passes from a thread spool (not shown) to thread hooks 24 and 25.
Renoid device 22. The thread guide 20 is inserted between the motor pulley 13 and the guide roller 16, and the tension pulley 11. Through the thread guide 19, the thread take-up 21.
is guided to needle 26.

27 is a control device, each terminal 5゜6.2 of the detection device 3
, a pulse motor 12 and a solenoid device 22 are connected. FIG. 2 shows a block diagram of the present invention, in which the control device 27 includes a transmitter 28, a dart control 29. Motor driver 3 Q.

It has a supply yarn amount setting device 31. 32 is a timing pulse generator that generates pulses synchronized with the rotation of the main shaft of the sewing machine. The transmitter 28 is a unit that generates a reference pulse to be applied to the pulse motor 12.
The reference pulse generated in step 8 is sent to the dart control 29, where it is processed into pulses corresponding to the amount of the supply system, and sent to the motor driver 30 in accordance with the timing signal from the timing pulse generator 32, which drives the pulse motor 12. to drive.

The supply thread amount setting device 31 gives the number of pulses for the amount of supply system processed by the dart control 29, and stores standard A pulse number data of the amount of thread consumed according to various types of sewing, and can be used for detection during sewing. standard i as required by the signal from device 3.
4 Rus number given iJ? The number of pulses is increased or decreased and sent to the dirt control 29. In addition, if the sewing is not a sewing in which the amount of thread consumption changes significantly from needle to needle, such as straight sewing or simple zigzag sewing, the standard pulse number data for each stitch should be stored in the supply thread amount setting device 31 in advance. Instead of setting it up, first set the appropriate settings. It is also possible to provide a pulse number and then gradually obtain an appropriate pulse number based on the signal from the detection device 3.

Next, the operation of this device will be explained using the timing chart shown in FIG.

In FIG. 3, (A) shows the amount of needle bar displacement, and the horizontal line in the center represents the needle plate surface. (B) is the amount of balance displacement, (C
) indicates the operation timing of the solenoid device 22, and the solenoid device 22 is activated by the timing signal from the timing nozzle generator 32 to lock the upper thread 23 when the thread take-up 21 enters the rising process. As the thread take-up 21 further rises, thread tightening is performed at the thick line portion of the thread take-up displacement line.

When the thread tightening is completed, the solenoid device 22 is also released by the timing signal, and the upper thread 23 is released, allowing the needle thread 23 to be continuously fed out by the cruise motor 12.

(2) indicates the sampling timing of the detection device 3, and sampling of the detection device 3 is performed when the system tension is maximum, that is, when the balance 21 is at the uppermost position. Here, if the amount of the supply system is insufficient compared to the amount of yarn consumed, the needle thread 23 will be under tension during sampling, so the detector 9
Tenjonggoo! j-11 is pulled down, the detector 9 rotates counterclockwise in FIG. 1 against the sensor spring 10, and the detector 9 comes into contact with the make contact terminal 5.

Further, when the amount of the supply system is too large, the needle thread 23 is relaxed even during sampling, and the detector 9 is in contact with the break contact terminal 6. On the other hand, when the amount of the supply system is appropriate, the detector 9 is separated from both contact terminals 5 and 6 and located in the middle thereof at the time of sampling. Therefore, common terminal 7
When the make contact terminal 5 is at the H level during sampling, the amount of needle thread supplied for the next stitch is increased, and conversely, when the break contact terminal 6 is at the H level, the amount of needle thread supplied is increased. and when both are at L level, control is performed to maintain the same supply system amount next time. That is, when the make contact terminal 5 is at H level, the number of pulses is increased by a predetermined number, and when the break contact terminal 6 is at H level, the pulse is increased by a predetermined number of A? The number of pulses is decreased, and when both pulses are at L level, the pulse motor 12 is driven with the same number of pulses. z＃
The drive of the lever, X-[:-JX 12 is based on the timing signal from the timing pulse generator 32.
This is carried out after the thread tightening operation is completed and before the next thread tightening is started, and the upper thread 28 is paid out by the motor cooler 13 and the guide roller plate action. □”′(
The odor is the level of the make contact terminal 5, (F) is the level of the break contact terminal 6, (G) is the increasing pulse, () 0 is the decreasing A
(I) An example of a drive pulse of the Hapulus motor 12 is shown. To explain this example, first, when sampling the first stitch (left side in the figure), the break contact terminal 6 is at the H level, so a decreasing pulse is generated and the pulse motor 1 is
2, the number of drive pulses is decreased by a predetermined number, and the amount of supply system for the next stitch is decreased. Also sampling of the second stitch (
Since the make contact terminal 5 is at the H level (in the center of the figure), an increasing pulse is generated to increase the number of drive nockles. In the sampling of the third stitch (right side in the figure), since both terminals 5 and 6 are at the L level, the nof pulse number is maintained as it is without increasing or decreasing.

That is, the device of the present invention determines whether the upper thread was too much, insufficient, or appropriate in the previous stitch based on the detection signal 1 of the detection device 3 during the previous stitch formation, and based on the result. The amount of the supply system for the next stitch formation is determined, and the supply is made until the next thread tightening begins.

In the above embodiment, the detection device detects excess or deficiency in the supply system amount by bringing the detector into contact with the contact terminal, but the detection device in the present invention is not limited to this, and for example, the detection device in the present invention is not limited to this. A displacement detection element may be used in the terminal provided, or a pressure detection element may be used to detect excess or deficiency in the amount of the supply system.

As described above, according to the present invention, it is possible to sequentially feed out a portion of the amount of thread for each stitch, and even if there is a fluctuation in the amount of thread consumed, the amount of the supply system can be adjusted immediately, so that sewing can always be performed appropriately. This allows sewing with stable thread tension without thread breakage or skipped stitches.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main parts of a sewing machine in which the present invention device is attached to a sewing machine arm body shown by phantom lines, FIG. 2 is a block diagram of the present invention, and FIG. 3 is a timing diagram of the present invention. DESCRIPTION OF SYMBOLS 1... Sewing machine arm body, 2... Base, 3... Detection device, 4... Needle thread supply device, 5, 6.7... Terminal, 9... Detector, 10... ...Sensor spring, 11...
Tension gooley-112...Pulse motor, 13.
...Motor coolie, 14...Guide roller plate, 16
...Guide roller, 18...Spring, 19.20...
・Thread guide, 21... Balance, 22... Renoid device, 23... Upper thread, 26... Needle, 27... Control device, 28... Transmitter, 29... Key 30... Motor driver, 31... Supply yarn amount setting device, 3.2... Timing pulse generator.

Claims (1)

[Claims] The needle thread diameter of the sewing machine is determined by a needle thread supply device that sequentially feeds out the amount of thread for each needle, and a detection device that detects excess or deficiency of the supply system amount relative to the amount of thread consumed for each needle. 1. An automatic needle thread supply device for a sewing machine, characterized in that the supply system amount of the needle thread supply device is controlled in response to a detection signal from the detection device.