JPS61290982A - Sewing of cloth - 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] Retired Emperor of Industry ■Rikyuu! The present invention relates to a fabric sewing method in which a body fabric and a trumpet-shaped tape fabric are fed to a needle drop of a sewing machine and the trumpet-shaped tape fabric is sewn to an end of the body fabric. Regarding the control method of Tensilan that should be added to the.

Conventionally, the above-mentioned sewing method is used, for example, to sew the sleeves and edges of stockinette shirts. By the way, since the trumpet-shaped tape fabric is drawn out while being formed in a trumpet tube provided before the needle drop of the sewing machine, it is sewn onto the body fabric with some tension.

Therefore, in order to prevent wrinkles from forming on the sewn product,
Appropriate tension (on the body fabric side) in the direction opposite to the fabric movement direction (
Hereinafter, tension in this direction is referred to as back tension) and must be supplied to the plan.

For this reason, in the past, a braking roller was provided on the body fabric, and back tension was applied to the body fabric by the braking torque generated as the roller rolled.

However, although the above conventional method applies back tension to the body fabric using the braking force of the roller, the amount of back tension is not controlled and is extremely unstable. The magnitude of the back tension varies depending on usage conditions, etc., and as a result, the finished dimensions of the sewn product vary, and there are problems in that it is difficult to sew to the desired finished dimensions.

In addition, since the magnitude of the back tension is not controlled as described above, the magnitude of the back tension may also change as the rotation of the sewing machine changes, resulting in the following problems. In other words, whether the sewing machine is operated automatically or manually, the sewing machine starts from 0 rotations each time the starting edge of the fabric reaches the planned speed, reaches a high speed of 4500 rotations (γpm) in a short time, and Since the end of the sewing machine rapidly decreases from high speed to O rotation each time the end of the sewing machine reaches the planned speed, the amount of back tension applied to the fabric changes greatly due to changes in the rotation of the sewing machine, and as a result, the rotation speed of the sewing machine increases. There is a problem in that the sewing condition at the sewing location becomes uneven during the rise or fall, which deteriorates the quality of the product.

An object of the present invention is to provide a novel fabric sewing method that solves these problems.

To achieve the above-mentioned object, the present invention provides a method for sewing the wrapper-like tape material to the end of the body material by feeding the body material and the wrapper-like tape material to a sewing machine, the needle A braking force generating body that always generates a constant braking force is installed before the sewing machine drops, and when this braking force generating body is brought into contact with the fabric that is supplied to the sewing machine, the braking force generated by the braking force generating body causes the sewing machine to move against the fabric. It is characterized by a constant back tension that is independent of rotation speed.

The braking force generated by the dish braking force generator applies constant back tension to the body fabric before the needle drops, regardless of the rotational speed of the sewing machine. Since this sewing condition is common to all products, the finished dimensions of the sewn products are the same for all sewn products, and high-quality sewn products can be mass-produced.

Fig. 1 is a diagram showing an example of implementing the method of the present invention.
is a fabric presser, and a feed dog (not shown) for forcibly feeding the fabric is provided on the fabric placement surface 2 below it. Reference numeral 3 denotes a sewing needle, and a guide plate 4, a clothing roller 5 as an example of a braking force generator, and a presser roller 6 are arranged in that order in front of the sewing needle in the cloth moving direction Q relative to the sewing needle. Reference numeral 7 denotes body fabric, which is conveyed close to the plan P by an endless band (not shown) provided on the fabric placement surface 2. The illustrated body fabric 7 is made from the unfolded sleeves of stockinette underwear. 8
is a trumpet-shaped tape fabric, and the tape fabric is stretched out while being curved in a trumpet tube 9 provided in front of the plan P, and is supplied to the plan P.

The guide plate 4 and the pressing roller 6 function to prevent the body fabric 7 from being lifted up together with the clothing roller 5 when it is lifted up by the operation of a rotary solenoid, which will be described later. Further, the pressing roller 6 also has the function of guiding the body material 7 to the plan P. The clothing roller 5 is, for example, a cylindrical drum 5a with a large number of dogleg-shaped needles 5b planted on the circumferential surface thereof, and rolls on the body fabric 7 while piercing the needles 5b... . This clothing roller 5 is provided in a drive unit as shown in FIG. The drive unit includes a fixed base 1) fixedly provided to the fabric placement surface 2, and a sleight of hand slidably provided to the fixed base 1) in a direction R perpendicular to the fabric moving direction Q. 12, a transmission case 13 provided to be able to swing up and down with respect to the slide table 12, a rotary solenoid 14 for swinging the transmission case 13, and a DC solenoid attached to one end of the transmission case 13. A clothing roller 5 is supported on the other end of the transmission case 13, and is connected to the DC motor 15 via a timing belt (not shown) inside the transmission case 13. Said slide table 1
2 is slidably driven by a stamping motor 16. As shown in FIG. 2, the stamping motor 16 has fabric edge detection optical sensors 17a and 17 provided on the fabric placement surface 2.
b... is connected through a control system (not shown), and the fabric movement direction Q is held with the body fabric 7 held by the clothing roller 5 so that the edge of the fabric detected by the optical sensor coincides with a predetermined reference line n. move in the direction perpendicular to The control of the edge of the fabric by a control system including such a light sensor and a clothing roller is known, for example, in Japanese Patent Application Laid-Open No. 59-1-5078. The rotary solenoid 14 raises the clothing roller 5 when there is no clothing material 7 under the clothing roller, and lowers the clothing roller 5 when the clothing material 7 is present. Whether or not the body material is present below the clothing roller 5 is detected by an appropriate optical sensor (not shown).

The DC motor 15 drives the body fabric 7 via the clothing roller 5.
For example, the fourth
It is connected to a control circuit as shown in the figure. This control circuit includes four operational amplifiers U1 to U4 and a transistor Tr1 that controls the voltage (+V) applied to the DC motor 15.
, a transistor Tr2 that controls the current flowing to the DC motor 15, a voltage-monitoring voltage dividing resistor R1, R2, a current-monitoring resistor R3, and a current-monitoring resistor R in constant current mode.
It is composed of 4th grade.

The operational amplifier U1 monitors the voltage applied to the DC motor 15 through the voltage dividing resistors R1 and R2, and controls the base current of the transistor Tri to keep the voltage constant. That is, the operational amplifier U1 and the transistor Tri constitute a constant voltage circuit that maintains the voltage applied to the DC motor 15 in a constant voltage mode.

The operational amplifier U2 monitors the armature current of the DC motor 15 through the resistor R3 to protect the DC motor 15 from overcurrent.

The operational amplifier U3 monitors the armature current of the DC motor 15 through the resistor R3, and stops the operation of the constant voltage circuit when the direction of the current is reversed and the current value reaches a predetermined value. The direction of the armature current is reversed because the back electromotive force has become higher than the applied voltage, which means that the DC motor now functions as a generator.

The DC motor functions as a generator in this way when the body fabric 7 serving as the load of the DC motor is fed at high speed and the rotational speed of the armature becomes higher than the predetermined rotational speed of the DC motor. Note that when the DC motor functions as a generator, the current flows through the transistor Tr2 to the power supply side (
-V).

The operational amplifier U4 monitors the magnitude of the armature current through the resistor R4, and controls the base current of the transistor Tr2 so that the current value is constant.

As a result, the DC motor 15 functions as a generator, and when the magnitude of the armature current at that time reaches a predetermined value, it is thereafter operated in constant current mode.

Here, since the motor torque is proportional to the armature current,
Monitoring the armature current through R3 and R4 is the same as monitoring the motor torque, and operating the generator in constant current mode means that the generator (DC motor) has a constant braking torque. means that it is occurring. The operation of the control circuit described above is schematically represented by the characteristic curve shown in FIG. In the figure, the broken line A is the applied voltage, the chain line B is the back electromotive force, and the solid line C is the voltage difference between the applied voltage and the back electromotive force, which is proportional to the armature current (braking torque).

Also, the light is the switching point between constant voltage mode and constant current mode.

According to the above configuration, until the DC motor 15 starts to generate a predetermined braking torque, it is rotated in a constant voltage mode, so the body fabric 7 is forcibly fed to the target by the clothing roller 5. Then, when the fabric feed by the feed dog (not shown) speeds up and the braking torque of the DC motor I5 reaches a predetermined value, it switches to constant current mode, and from then on, the DC motor 15 operates regardless of the moving speed of the body fabric. A constant braking torque is generated and a constant back tension is applied to the body fabric 7 via the clothing roller 5. In this case, the magnitude of the set torque at the switching point between constant voltage mode and constant current mode is appropriately determined, and the torque is applied to Good sewing conditions can be achieved by applying a constant back tension to the fabric.

In the above configuration, a clothed roller is used as the braking force generator, but it goes without saying that the present invention is not limited to this. However, if a clothing roller is used, the needles on the peripheral surface pierce the body fabric and roll on the body fabric without slipping, making it possible to faithfully transmit the braking torque generated by the DC motor to the body fabric. It's good to be able to do it.

Further, in the embodiment, a constant braking torque is generated by a DC motor, but a similar braking torque may be generated by an AC motor.

As explained above, according to the fabric sewing method according to the present invention, a constant back tension can be applied to the body fabric regardless of the rotational speed of the sewing machine. Uniform sewing conditions can be obtained, and since a constant back tension is applied to each piece of fabric, the finished dimensions of each product are constant, making it possible to mass-produce high-quality sewn products.

In addition, if the braking force generator is configured using a DC motor and its control circuit as in the embodiment, the magnitude of the braking torque generated by the DC motor can be adjusted to an arbitrary value, thereby improving the quality of sewn products. can be controlled to achieve the desired finished sewing dimensions, making it very useful.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing a sewing device for carrying out the method of the present invention, FIG. 2 is a plan view of the device shown in FIG. 1, FIG. 3 is a perspective view showing a clothing roller drive unit, and FIG. 4 is a DC motor. FIG. 5 is a diagram illustrating the operation of the DC motor.

Claims (3)

[Claims] (1) A method in which the body fabric and the trumpet-shaped tape fabric are fed to the needle drop of a sewing machine and the trumpet-shaped tape fabric is sewn to the end of the body fabric, and a certain braking force is generated before the needle drops. A braking force generating body is provided, and this braking force generating body is brought into contact with the fabric supplied to the needle drop, and the generated braking force applies a constant back tension to the fabric that is independent of the rotational speed of the sewing machine. A fabric sewing method characterized by: (2) The fabric according to claim (1), wherein the braking force generator is a clothing roller that is provided to be able to roll on the body fabric in front of the needle drop of the sewing machine. Sewing method. (3) The clothing roller is connected to a DC motor which is controlled to be driven in a constant voltage mode until a predetermined torque is reached by a control circuit, but to switch to a constant current mode when the torque exceeds a predetermined torque. 2. The fabric sewing method according to claim 2, wherein the back tension applied to the body fabric is kept constant by a constant braking torque generated when the motor is in a constant current mode.