WO2001085591A1

WO2001085591A1 - Thread-tension and thread-length controller

Info

Publication number: WO2001085591A1
Application number: PCT/KR2001/000734
Authority: WO
Inventors: Gung-Kee Nam
Original assignee: Dnt Co., Ltd.
Priority date: 2000-05-09
Filing date: 2001-05-07
Publication date: 2001-11-15
Also published as: KR20010103312A; AU2001256814A1; JP2002020038A; CN1172838C; TW483956B; CN1427796A

Abstract

Disclosed is a thread-tension and thread-length controller, comprising sensing means for detecting thread-tension at a trailing edge by means of strain gauges, amplifying means for amplifying an output of the sensing means, thread-length measuring means for measuring a thread-length outputted in a pulse form according to phase variation by comparing output signals with one another, which were divided due to a phase difference in three phases of a motor, through a comparator and inducing magnetism through a rotation, displaying means for displaying an operated condition on a screen, actuator means for maintaining the thread-tension to a desired level by using the small size brushless motor employing an oiless metallic bearing, cutting means for cutting threads, communication means for transmitting the thread-tension variation and the work condition measured by a communication protocol to a central system and storing the data, and control means for outputting control signals to maintain the thread-tension to be constant according to the thread-tension variation. The present invention has advantages of accurately controlling the thread-tension by directly detecting the thread-tension through a thread-tension sensor, and extending a life by using the small size brushless motor employing the oiless metallic bearing as well as ensuring a remote diagnosis and control by using a two-way communication.

Description

THREAD-TENSION AND THREAD-LENGTH CONTROLLER

Technical field

The present mvention generally relates to a thread-tension and thread- length controller, and in particular, to a thread-tension and thread-length controller, which can accurately control a thread-tension by directly detecting the thread- tension by means of a thread-tension sensor, and can extend a life by using a small size brushless motor employing an oiless metallic bearing as well as ensuring a remote diagnosis and control by using a two-way communication.

Background art

In general, a weaving machine for weaving fabrics includes a thread twister for twisting threads and a winder for winding the threads in preparation for a weaving process using the thread twister.

In the winder, a thread-tension controller using elasticity of a spring is mounted on a roll to maintain a thread-tension to a constant level and also serve to cut the threads, when the threads wound on each shaft are judged to reach a predetermined length after calculating the whole length of the threads wound on the each shaft. At this time, if the thread-tension of the threads is not constant, the actual thread-length wound on the shaft is turned out to be different from each other. Since thread remainders after finishing the final work are supposed to be discarded, a function of the thread-tension controller is so much important for the winder.

The conventional thread-tension controller senses a thread feeding speed and keeps the speed to be constant by using elasticity of the spring, thereby maintaining the thread-tension to be constant.

The conventional thread-tension controller, however, has a drawback that it can not control accurately the thread-tension, since it controls the thread-tension by sensing the speed and keeping the speed to be constant instead of directly sensing the thread-tension.

The conventional thread-tension controller has another drawback that it needs a separate thread-tension measuring unit to directly measure the thread- tension. Even after the thread-tension measuring unit is newly installed, there occurs a thread-tension variation, since it is structurally designed to maintain the thread-tension by differing an intersecting angle of the threads from each other through the elasticity of the spring.

The conventional thread-tension controller has still another drawback that its life becomes relatively shortened due to an abrasion heat generated in the course of corresponding to the speed variation at high velocity, since it employs a ball bearing as a motor for controlling the threads feed.

The conventional thread-tension controller has yet another drawback that it fails to perform an equipment diagnosis, since it ensures only a setting through a one-way communication.

Still, there has not been developed an effective and appropriate thread- tension controller yet, which can obviate the aforementioned drawbacks. It is urgently needed to develop that effective and appropriate thread-tension controller.

Disclosure of Invention

It is, therefore, an object of the present invention to provide a thread- tension and thread-length controller, which can accurately control a thread-tension by directly detecting the thread-tension through a thread-tension sensor, and can extend its life by using a small size brushless motor employing an oiless metallic bearing as well as ensuring a remote diagnosis and control by using a two-way communication.

It is another object of the present invention to provide a thread-tension and thread-length controller, which can function as a shock absorber of threads when a motor is controlled to maintain a thread-tension variation to be constant by intersecting the threads on a pre-tenser formed at a leading edge of a rolling pulley, and can have a spring with enough elasticity to protect an excessive thread-tension from being applied thereto. To achieve the above objects, there is provided a thread-tension and thread- length controller according to the present invention, the controller including sensing means for detecting thread-tension at a trailing edge through strain gauges, amplifying means for amplifying an output of the sensing means, thread-length measuring means for measuring a thread-length outputted in a pulse form according to a phase variation by comparing output signals with one another, which were divided due to a phase difference in three phases of a motor, through a comparator and inducing a magnetism through a rotation, displaying means for displaying an operated condition on a screen, actuator means for maintaining the thread-tension to a desired level by using the small size brushless motor employing an oiless metallic bearing, cutting means for cutting the threads, communication means for transmitting the thread-tension variation and the work condition measured by a communication protocol to a central system and storing the data, and control means for outputting control signals to maintain the thread- tension to be constant according to the thread-tension variation.

Brief Description of the Drawings Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating a thread-tension and thread-length controller according to an embodiment of the present invention;

FIG. 2 is a cross view of the thread-tension and thread-length controller according to the embodiment of the present invention;

FIG. 3 is a plan view of the thread-tension and thread-length controller according to the embodiment of the present invention; FIG. 4 is a side view of the thread-tension and thread-length controller according to the embodiment of the present invention;

FIG. 5 is a view showing a structure of a principal part of the thread- tension and thread-length controller according to the embodiment of the present invention; FIG. 6 is a view showing a structure of a thread guide of the thread-tension and thread-length controller according to the embodiment of the present invention;

FIG. 7 is a sectional view showing a structure of a pulley and a motor of the thread-tension and thread-length controller according to the embodiment of the present invention;

FIG. 8 is a view showing a structure of a sensing part of the thread-tension and thread-length controller according to the embodiment of the present invention;

FIG. 9 is a view showing an arrangement of strain gauges of the thread- tension and thread-length controller according to the embodiment of the present mvention;

FIG. 10 is a view showing a waveform of signals inputted to a central processor of the thread-tension and thread-length controller according to the embodiment of the present invention; and

FIG. 11 is a view showing a waveform of signals filtered by the central processor of thread-tension and thread-length controller according to the embodiment of the present invention.

Best Mode for Carrying Out the Invention

The present invention will now be described in connection with preferred embodiments with reference to the accompanying drawings. For reference, while the invention has been shown and described with reference to certain a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. As shown in FIGS. 1 through 5, a thread-tension and thread-length controller according to a preferred embodiment of the present invention includes a sensing part 10 for detecting a thread-tension at a trailing edge, an amplifying part 20 for amplifying an output of the sensing part 10, a key input part 30 for inputting instruction and data by a user, an electrical angle part 40 for measuring a thread-length outputted in a pulse form according to a phase variation by comparing output signals with one another, which were divided due to a phase difference in three phases of a motor, through a comparator and inducing a magnetism due to a rotation, a display driving part for operating a displayer 60, the displayer 60 for displaying an operated condition on a screen, the exclusive control comparator 70 for synthesizing inputted PWM signals with outputted PWM signals over lOOKHz, transmitting the same to an actuator 90 and driving the motor installed at a leading edge of the sensor to control a thread feeding speed, am amplifier for amplifying an output of the exclusive control comparator 70, the actuator 90 for maintaining the thread-tension to a desired level, a cut driving part 100 for driving a cutting part 110, the cutting part for cutting threads, a communication converter 120 for setting a value and detecting a condition through a two-way communication protocol of the system to automatically measure a thread-tension variation of a winder and transmitting the measured thread-tension variation and work condition to the central system to store the data, and a central processor 130 for calculating a control volume according to the thread-tension variation and converting the control volume into the PWM signals to be outputted.

Operations of the thread-tension and thread-length controller constructed as above according to the preferred embodiment of the present invention will be explained herein below.

First, the sensing part 10 actually detects the thread-tension by means of strain gauges and converts the thread-tension into electrical signals to be outputted. The amplifying part 20 amplifies the signals outputted by the sensing part 10 and outputs the same to the central processor 130.

The sensing part, as shown in FIG. 8, is constructed to have the strain gauges 16 at both sides of a plate spring 15. If there occurs the thread-tension variation, the plate spring 15 on which a thread-pressure is applied suffers a displacement thereof. Accordingly, a current outputted by the strain gauges 16 becomes converted, thereby allowing detection of the thread-tension. That is to say, the sensing part 10 can directly detect the thread-tension variation created due to a fine change in a thread feeding speed by means of the plate-spring 15 and the strain gauges 16 capable of detecting a fine displacement of a force applied to the threads.

The strain gauges 16, as drawn in FIG. 9, are circuitally constructed to have two reference resistances 14 and be of a bridge form. The present invention can detect the fine displacement by using the two strain gauges, in contrast to a. general load cell method using four strain gauges, and by being connected in the bridge form, whereby it ensures a sufficiently fast responsivity within 20usec, the maximum delay time.

The amplifying part 20 converts the thread-tension variation detected by the sensing part 10 through an analogue to digital converter into digital signals and amplifying the digital signals to be outputted, so as for the central processor 130 to recognize the digital signals as the thread-tension value. In the signals inputted from the sensing part 10 to the central processor 130 through the amplifying part 20, as illustrated in FIG. 10, since a vibration generated due to an operation of a weaving machine becomes inputted three times the thread-tension variation, the central processor 130 tells normal thread-tension signals from noise signals caused by the vibration of the machine by employing a software technology, namely a median filter method, whereby the noise signals are removed and the normal thread-tension signals are selected as best shown in FIG. 11. The central processor 130 employs an exclusive processor driven at a high PWM frequency of lOOKHz, thereby achieving a responsivity within 30msec at a high-speed. After sensing the measured thread-tension, the central processor 130 calculates a difference between a given thread-tension value and the measured thread-tension value and induces an operation of the motor comprised in the actuator 90 into a desired operation, so that a rotatory force variation of the motor can change the thread-tension, causing torque. As for the motor, as viewed in FIG. 7, a three-phase induction motor is used, in which a pulley 97 is connected to a motor shaft 91 rotatable due to the rotatory force created by the phase variation in a magnetic force of a coil and a magnet. Since the pulley 97 is such constructed that threads passes a peripheral line thereof to be wound thereon, the central processor 130 maintains or changes the thread-tension through the pulley 97 by changing the rotatory force of the motor. The three-phase induction motor provided to maintain the thread-tension as above is of a brushless-type. In an attempt to extend a life during use of the motor for a long time in response to the speed variation at high velocity, the motor prevents the life from being shortened due to a heat generation by employing the oiless metallic bearing 92 instead of a ball bearing and processing the oiless metalic bearing 92 and the motor shaft 91 with an error maintained within +3xl0^[" ^6]meter, and prevents a heat from being generated due to the torque variation by executing a heat emission through a regeneration and a P-P current limit through an overload limiting. The motor further manages to have an allowable error within 3micron in order to force the mother shaft 91 to be driven into the pulley 97 at 10-40Kg weight.

The present invention, in contrary to the conventional thread-tension control method using elasticity of a spring, appropriately adjusts the thread- tension measured after the motor rotates and the rotatory force of the motor by passing the threads through the pulley 97 and varying an inertia force of the rotation of the pulley 97 by means of the motor, thereby maintaining the thread- tension to be constant. In other words, the central processor 130 adjusts a balance between the rotatory force of the motor and the measured value attained by the sensing part 10 to maintain the thread-tension in accordance with the given thread-tension, and varies the rotatory force of the motor to be accorded to the adjusted balanced value.

Since the thread-tension is controlled by the pulley 97, the present invention should additionally install a pre-tenser 95, which intersects a passageway of the threads more than twice to lessen a thread-length variation due to the thread-tension variation and a thread-length variation due to the rotatory force variation of the motor between motors for thread-tension. Since an arm of the pre-tenser 95 absorbs a shock imparted to the threads with a certain force through the plate spring, the pre-tenser 95 protects the threads and the pulley 97 from running idle on a surface of the pulley 97 and enables a fictional force to be constantly maintained by providing a displacement required for the motor to maintain the thread-tension, which is varied at the input side.

Moreover, a sending process is applied to the surface of the pulley 97 to reduce an error of the thread-length caused by a slide of the threads on the pulley 97 and an oxide film process is also applied to the surface of the pulley 97 to reinforce the aluminum surface. Thereafter, a DLC(Diamond Like Carbon) evaporation is applied to remedy the life shortening problem due to the friction on the surface of the pulley 97. At this time, the aluminum is processed to have a thickness less than 3mm to reduce a response delay arisen due to the inertial force of rotation, and a low temperature evaporation at less than 200 degrees is executed during the oxide film process and the DLC evaporation process to minimize a deformation.

The central processor 130 measures the thread-length and instructs the cut driving part 100 to actuate the cutting part 110, which cuts the threads by a constant length. The central processor 130 uses an output pulse outputted due to the phase displacement of the motor to measure the thread-length. That is to say, the central processor 130 measures the thread-length by detecting a number of rotation of the pulley 97 connected to the motor shaft 91 through the output pulse outputted during the phase displacement of the motor. In this case, it is generally used a phase control method of an inverter for driving the three-phase induction motor. The central processor 130 employing the motor for controlling the thread- tension controls the threads to be cut at the same time when the motor is braked so as to prevent the threads from being entangled by a free rotation due to the inertia force of the rotation, which would give rise to a problem when the operation is completed.

The cutting part 110 cuts the threads by fixing a ceramic guide 111 for a thread-feed and fixing a cutting knife 112 to the guide 111. In the course of cutting the threads, for the purpose of a stable thread-cutting, the central processor 130 controls the motor attached to the leading edge of the censor to cut the threads in a state that the thread-tension between a bobbin and the motor is in a high level, and brakes the motor through which the threads pass to stop a continuous operation of the pulley 97, thereby preventing the threads from being wound on the pulley 97 further.

The central processor 130 employing the communication converter 120 for controlling a connection and a removal during the operation permits an automatic setting and operation to be conducted by the auto recognition communication protocol. The conventional art just allows a setting through a one-way communication. However, the present invention is capable of periodically reading and storing the condition of each node and instructing and ascertaining the condition by employing a two-way communication as well as automatically diagnosing and recognizing the condition of the equipment through the two-way communication.

The central processor 130 enables a user to input or control data through the key input part 30 and also enables the user to ascertain results generated during the operation by controlling the display driving part 50 to drive the displayer 60 to represent the results.

The present invention supplies an electric power of +5V, +12V and +24 V through an external single power source by virtue of a DC-DC converting device, and restrains the maximum current not beyond 1 A by checking a current loss.

A frame is manufactured so as for parts within a case to be fixed thereto, serving to removing a defective operation of the censor caused by a fine vibration. An ABS resin and a solution for electrostatic elimination are mixed together to intercept a harmful radio wave and a defective operation of equipments caused by an electromagnetic wave, and a particular paint may be used to preserve a strength of plastic material.

Industrial Applicability

As stated above, the present invention has an advantage of ensuring a production of high quality textiles by detecting the thread-tension variation generated by the thread feeding speed variation through the sensor and adjusting the thread-tension responsive to the detected thread-tension variation so as to basically avoid the problems generated by external factors causing the thread- tension variation.

The present invention has another advantage of achieving a quality management of the products by enabling the whole thread-tension to be controlled through the remote control, in which the thread-tension each work process is detected and the detected thread-tension is controlled by the central control system, thereby obtaining a constant maintenance and control of the thread-tension during the operation process.

The present invention has further another advantage of establishing foundation of a work using the standardized thread-tension and accurately managing the thread-tension suitable for characteristic of the product textiles.

The present invention has still another advantage of stabilizing a thread- tension by applying the small size and high output motor to measure the fine thread-tension variation uncontrollable by the machine and to stabilize the fine thread-tension, of maintaining the stabilized thread-tension responsive to the thread-tension variation at the input side, of decreasing the defective proportion due to the thread-tension by controlling the micro processor to manage the thread- tension, and of transmitting the measured thread-tension and the thread feeding speed to the main system, storing and maintaining the data.

The present invention has yet another advantage of ensuring a high quality production by enabling the work to be executed using the thread-tension variation due to the thread feeding speed variation of spindles caused in textile machines and the stable thread-tension generated in the winder process, and enhancing the product quality by conducting a perfect management of the thread-tension.

The present invention has yet another advantage of making possible the setting and the work control through the network communication, of establishing a base for prevention of defective work by thoroughly controlling the defective work, and of making also possible an additional connection with application programs, and the control and management by the central system.

The present invention has another advantage of enabling the particular textile process varying the continuous thread-tension to be performed by varying the thread-tension according to a pattern arrangement of any discretionary thread- tension.

Claims

What is Claimed is:

1. A thread-tension and thread-length controller comprising: sensing means for detecting a thread-tension at a trailing edge through strain gauges; amplifying means for amplifying an output of the sensing means; thread-length measuring means for measuring a thread-length outputted in a pulse form according to a phase variation by comparing output signals with one another, which were divided due to a phase difference in three phases of a motor, through a comparator and inducing a magnetism through a rotation; displaying means for displaying an operated condition on a screen; actuator means for maintaining the thread-tension to a desired level by using the small size brushless motor employing an oiless metallic bearing; cutting means for cutting threads; communication means for transmitting the thread-tension variation and the work condition measured by a communication protocol to a central system and storing the data; and control means for outputting control signals to maintain the thread-tension to be constant according to the thread-tension variation.

2. The controller of claim 1, wherein the small size brushless motor is processed for the oiless metallic bearing and a motor shaft to be maintained within an error of ±3xl0^["6]meter.

3. The controller of claim 1, wherein in the small size brushless motor, a sending process is applied to a surface of a pulley to reduce an error of a thread-length caused by a slide of the threads on the pulley and an oxide film process is also applied to the surface of the pulley to reinforce the aluminum surface, and thereafter a DLC (Diamond Like Carbon) evaporation is applied.

4. The controller of claim 1, wherein the strain gauges are two in number and of a bridge shape in circuitry along with two reference resistances.

5. The controller of claim 1, wherein the control means controls the threads to be cut at the same time when the motor is braked to prevent the threads from being entangled by a free rotation due to an inertia force of the rotation, which would give rise to a problem when the operation is completed.

6. The controller of claim 1, wherein the communication means periodically reads and stores a condition of each node and instructs and ascertains the condition as well as automatically diagnosing and recognizing the condition through a two-way communication.