Title of Invention	AN APPARATUS FOR CONTROLLING BREAKAGES OF LONGITUDINALLY STRETCHED ARTICLE IN A SPINNING MACHINE
Abstract	An apparatus for controlling breakage of a longitudinally stretched article in a spinning machine and maintaining uniform spinning tension by varying the spindle speed of lthe machine with respect to the end breakage levels. The system involves sensor means for sensing process condition/article condition at each spinning machine, microprocessor based machine station for acquisition of process condition/article data from said sensors and a machine station adapted to control lthe spinning machine speed based on the article condition/process sensed.

Title of Invention

AN APPARATUS FOR CONTROLLING BREAKAGES OF LONGITUDINALLY STRETCHED ARTICLE IN A SPINNING MACHINE

Abstract

An apparatus for controlling breakage of a longitudinally stretched article in a spinning machine and maintaining uniform spinning tension by varying the spindle speed of lthe machine with respect to the end breakage levels. The system involves sensor means for sensing process condition/article condition at each spinning machine, microprocessor based machine station for acquisition of process condition/article data from said sensors and a machine station adapted to control lthe spinning machine speed based on the article condition/process sensed.

Full Text	The present invention relates to a system for controlling breakage of a longitudinally stretched article in a spinning machine and maintaining uniform spinning tension by varying the spindle speed of the machine with respect to the end breakage levels. In order to attain optimum spinning conditions, in which higher production, labour productivity and good yarn quality are the main requirements, end break levels are to be reduced and maintained so that higher spindle speeds and other optimum conditions can be arrived at. An end breakage in spinning is an occurrence in which discontinuity in spinning process is caused due to a situation when tension placed on the yarn during spinning exceeds the yarn strength. To explain, at higher spindle speeds, the spinning tension increases and as a result of higher spinning tensions, the difference between the yarn breaking force and the tension placed one the yarn becomes much less and therefore the probability of end break increases. Tension in yarn during spinning occurs due to various conditions such as poor raw material quality, non- optimised spinning preparatory processes, machinery conditions and various setting parameters of spinning process, varying ambient conditions and poor material handling. In our co-pending application No. 1321/Cal/98 there is provided a system for providing the yarn laid-in a slack form to attain uniform test conditions for yarn in an yarn tensile testing method comprising: - means to vertically holding the yarn to be tested comprising a top clamp and a bottom clamp and suction unit loosely holding the leading end of the yarn passing therethrough said top and bottom clamps, said top clamp being fixed and the bottom clamp movable; a plunger actuating unit having means for effecting a movement of an actuating member thereof to thereby pull required yarn length from said suction unit for laying in slack form of the yarn to be tested therebetween said top and bottom clamp, said bottom clamp having means for clamping said yarn after said laying in slack form of said yarn and said plunger actuating unit further having means for retracting said actuuating member thereof to its original position after claiming of said bottom clamp to thereby provide for slack laying-in of the yarn to be tested therebetween said top and bottom clamps. Our other co-pending application No. 1322/Cal/98 is directed to a system for constantly measuring mass variation of a longitudinal material in a continuous process of its manufacture requiring liner distribution and uniformity comprising: sensor means to sense a linear mass distribution of the material at the various stages of processing at the various subsystems; means to activate the sensor means for acquisition of product status at every sub station; - means to store the standard parameters of product status at every stage of processing at respective sub status; means to analyze and compare the data sensed by said sensor with respect to said standard parameters; control unit to generate working status signal to the various subsystems based upon comparative analysis carried out by said means for analyzing and comparing; a communication control means interfacing therebetween said means for activating, storing, analyzing and comparing said sensed data and said control unit and also with the various subsystems to the control unit for effecting necessary control in processing. Primary among the various factors which influences and breakage levels is spindle speed of the running machine and it offers an advantage that this can be successfully varied to control the end breakage level unlike other factors such as raw material quality which cannot be altered at the final stages of spinning processes. When yarn tension is measured during a yarn package build up from the beginning to the end of the yarn package while spinning the yarn, a long-term change in tension between two extremes of yarn package build up can be noted. At the beginning of yarn build-up, the spinning tension will be significantly higher than the end of the build-up. This excess tension in the beginning of the build up has a negative effect on the yarn quality and on the running conditions at this phase of the build up. It is therefore essential to control the tension at the initial stage of the cop build up inorder to maintain the end breakage rates uniformly and at a lower level throughout the doff. In order to atleast reduce the disadvantage of higher spinning tension at the beginning of the cop build, a 2 stage drive system available commonly serves the purpose to some extent. Two stage drive systems use two motors, one running at slow speed and other at high speed according to the required time for which these have to operated. This system makes possible the reduction of speed (and therefore a reduction of the spinning tension to a normal level) at the beginning of the cop build and at the end. Accompanying Figure 1 shows the resulting conditions of spinning tension with such a system. It is seen from Figure 1 that the excess tension at the beginning and at the end is eliminated. As a result, the working performance in spinning is considerably improved due to a reduction in end breakage rate at these levels. The limitation as the maximum spindle speed is therefore removed and consequently the average speed could be increased from the prevailing level, thus increasing the production of the machine. A certain disadvantage, with this system, however, is the sudden surge in spinning tension at the speed change-over point which results in a change in yarn quality characteristics and spinning performance at this point. As a result, though the system is an improvement over the constant speed arrangement, it is not entirely suitable for very high production spinning. Extending the concept introduced by the two-stage spinning process, several advancements took place with the prime intention of increasing the speed over a definite number of steps so that the change over of speed is not very abrupt. One such system is the VPS (Vari Pitch Sheare) drive system. VPS drives are commonly used and mechanically controlled. In VPS drive, motor will run at constant speed only. The VPS varies the speed of ring frame in finite steps by varying the pitch diameter of the V-belt sheaves. This is automatically done during working of the ring frame by changing the sheave diameter from minimum to maximum. The problems associated with VPS is the range of speed variators limited to only a certain percentage (for eg. About 25%). Due to various moving parts, the VPS pulley needs frequent maintenance. However, these are relatively less costlier. With variators, speed adjustment is not carried out at the motor, but by means of adjustable grooved discs in the belt drive. In the variator, to get change in speed, change in diameter is effected by shifting the belt with two V-pulleys each made up by a respective pair of conically faced discs movable towards and away from each other. The adjustment is effected usually by a control device acting via pneumatic or hydraulic pistons and a lever mechanism. Another development in speed controlled drives for ring frame is inventer. These are power electronic motor controller and generally has no moving parts. These are available as part of ring frames or can be installed separately. The speed of motor is varied according to the speed setting adjustments programmed. The motor speed is controlled by controlling the supply frequency by means of a current controlled frequency converter, relays, voltage or using binary inputs. Inverters have no speed limit, but depends on the machine parameters, motors, etc. Inverters reportedly consume more power and are also relatively expensive. It is thus the basic objective of the present invention to provide an economical system for providing smooth change over of speed from the start of the doff to the end thereby maintaining uniform tension in the yarn. Another object of the present invention reside in that unlike in all the known methods described earlier, wherein the speed profile is defined by the user according to information on end breakages available with line to have a system wherein the change in speed is effected based on information obtained on line about the end breakages. Yet further object of the present invention is to provide a system wherein the end breakages could be controlled to a large extent by providing means for analyzing instantaneous end break and speed data and having means for adjusting spindle speed accordingly based upon said end breakage data. Yet further object of the present invention is to provide an improved method for controlling breakages of the stretched article utilizing the system of the invention. Yet further object of the present invention is to provide a closed loop control system to monitor and control the end breaks effectively. Thus according to the present invention there is provided a system for controlling breakage of longitudinally stretched articles in spinning machines comprising : at least one sensor means for sensing process condition/article condition provided at each spinning machine ; each said spinning machine operatively connected to a microprocessor based machine station for acquisition of process condition/article condition data from said sensors ; said machine station operatively connected to a electronic control unit provided to control the spinning machine speed based upon article condition/process condition sensed. In accordance with one aspect of the present invention the system for controlling breakage of longitudinally stretched articles in variator driven spinning machines comprise said process condition/article condition comprising information on end breaks of the stretched article and the spindle speed ; said micro processor based system providing to acquiring information on end breaks and the spindle speed from said sensors which is further transmitted to the said electronic control unit ; said electronic control unit having means for controlling the variator drive spinning assembly speed of the variator driven spinning machine based upon the end breakage data via a pneumatic control unit. In accordance with another aspect of the present invention the system for controlling breakage of longitudinally stretched articles in an inverter driven spinning machine comprise said processing condition/article condition comprising information on end break of said stretched article and spindle speed ; said microprocessor based system adapted to acquire information on end breaks and spindle speed from said sensors which is further transmitted on to said electronic control unit ; said electronic control unit having means for controlling the speed of the inverter driven spinning machine based upon the end breakage data. According to yet further aspect the invention provides for improvement in the method of controlling end breakage of longitudinally stretched articles in a spinning machine utilizing the system disclosed above comprising acquiring end break data from the machine station ; calculating the end breakage rate (EBR) after an observation cycle ; comparing the calculated EBR with standard values ; effectuating speed up or down control as required ; effectuating necessary changes in quantum of speed increase or decrease based on the input entry and speed input from machine ; transferring of control to pneumatic control unit and finally execution of controller. The present invention thus provides for the possibility of arranging a selective and continuous speed adjustment in spinning machine for the complete build-up. In this way, optimum conditions of spindle speed can be obtained such that, throughout the buildup, a practically constant spinning tension is available. Such a trace is shown in the accompanying figure 2. In the above system of the invention by way of an on-line monitoring system information is acquired from each and every spindle in a ring spinning machine by sensor means and in a controlled manner for improvement of machines productivity. In particular, each spinning machine consists of a set of sensors which are the components which collect information such as end breaks, speed, production etc. Informations from these sensors are connected to a "Machine Station". The machine station is controlled by a microprocessor which accepts data from the sensors. Each machine has a separate machine station. The machine stations are connected to a central unit (also called control unit) which has input / output devices for interaction with the user. The machine stations are periodically called up by the central unit for obtaining the information. The electronic control unit of the system is operatively linked to the machine station of the on-line monitoring system to collect information on end breaks periodically. This information is subsequently processed by the system and acted upon. The details of the invention its objects and advantages will be further apparent from the non-limiting exemplary embodiments of the system of the invention discussed hereunder with reference to accompanying figures wherein Fig. 3A shows a speed control device for variator driven spinning machines. Fig. 3B shows schematically the construction of the pneumatic control unit. Fig. 4 explains a device to control speed according to the methods explained in Figs. 7 and 8. Fig. 5 shows a speed control device for inverter driven spinning machines Fig. 6 shows schematically the construction of the electronic control unit used in the system of the invention. Fig. 7 explains the instantaneous speed control method with respect to a single setting condition. Fig. 8 explains the instantaneous speed control method with respect to multiple setting condition. Reference is first invited to Fig. 3A which shows a speed control device for variator driven spinning machines. Variator drive assembly (13), consists of taper shieves (5) and belt (6). The top variator drive assembly is connected to a motor (1) through motor shaft (2) and bottom of variator drive assembly is connected to tin roller (4) through tin roller shaft (3) . Input to the variator drive comes from a variator cylinder (7) which is pneumatically operated by a pneumatic control unit (8). The pneumatic control unit (8) gets the required signal from Electronic control unit (9) gets information from various sensor outputs (10) (one such sensor is a sensor (12) for measuring spindle speed) and machine inputs (11) programmed by the user. Reference is now invited to Fig. 3B which shows schematically the pneumatic control unit comprising of the two single solenoid valves and flow onto valve alongwith the pneumatic circuit diagram as illustrated. Speed control is effected by movement of the piston. Air flow into the piston is controlled by solenoid valves NC 1 and NC 2 as shown below : Referring to Fig. 3A spindle speed is varied by using the taper shieve pulleys (5) fixed on the tin roller shaft (3) and motor shaft (2). The ratio between the revolutions of these two shafts is governed by the position of the belt (6) running between the pulleys. By adjusting the position of the belt (6) on motor shaft pulleys (5.1), the transfer ratio can be adjusted. With different transfer rations, the required tin roller shaft speed is achieved. The piston (14) in the variator cylinder controls the position of the taper sheives (5.1 & 5.2). the position of the pistorn (14) is electronically controlled and the speed at which the machine is to be run as per the programmed settings (11) threads in electronic speed control unit (9) . Also, in case of frequency fluctuations, the speed of the tin roller shaft vary, which is monitored by tin roller shaft (12) and the sensor input is communicated to electronic control unit (9) which then effectuates necessary correction signals. The above speed control device (5) works in tandem with an online production monitoring system (2) to effectively vary the spindle speed of the spinning machine (1) as seen from Fig. 4. The on-line production monitoring system (2) has machine stations (3) available for every spinning machine. The machine station (3) collects informations such as spindle speed and end breaks from machine and passed on to a control unit (4) which consolidates the information and presents the report to the user. The device (5) collects these end breaks and spindle speed information directly from machine station (3) and alters the spindle speed of spinning machine after analysing the data based on the methods explained sufficiently in detail in Figs. 7 and 8. The device (5) explained here can be either variator driven as explained in Fig. 3A and 3B or inverter driven as explained in Fig. 5. Fig. 5 shows a speed control device for inverter drivers spinning machines. The motor (1) gets the speed signal from inverter (2) which can be of any type through an electronic control unit (3) . The electronic control unit (3) gets sensor inputs (5) from machine, and machine input (4) set by user to give necessary speed signal to inverter (2). Reference is now invited to the illustration in accompanying Fig. 6 when the construction detail of the electronic control unit are provided in the form of a functional schematic diagram. The electronic control unit consists of two Micro controllers controlled by the software in their respective ROMs. One of the micro controllers MC1 receives user input such as settings from the keyboard through a Keyboard / Display controller and transfers serially to the other controller MC2. The same settings are stored in a Non-volatile RAM (NVRAM) controller. MC2 reads the setting and stores it in the RAM sequentially. End break information from the machine station (of the on-line monitoring system) is acquired and processed by the micro controller MC2 and stored in the RAM memory. Information on stops, doffs, tinroller speed and front roller speed which is necessary for the functioning of the device are obtained by Input/Output control unit and transferred to MC1. After completion of the observation cycle, Controller 2 (MC2) calculates the reference speed and also the EBR. Now EBR is compared with the corresponding block settings available in the memory and the speed is transferred serially to the Controller 1 (MC1), whereafter the controller bypasses all the pattern control and the control is switched to the new speed calculated and assigned by the Controller 2 (MC2). In particular, in the electronic control unit the said Controller 1 (MC1) performs two serial operations a) Communication with the PC (Bi-directional) and b) Communication with the Controller 2 (MC2) (Bi-directional), while Controller 2 (MC2) performs two serial operations a) Communication with Controller 1 (MC1) (Bi-directional) and b) Communication with Machine Station (Unidirectional). The above functional operation is the same for both Inverter based and variator based systems. The difference only being in the mode of effecting the change in speed. In the case of Inverter, MC1 gives the change signal through a Digital to analog converter (DAC). In case of Variator based system the speed change will be effected through a pneumatic control unit. Optionally, the electronic control unit can be connected a personal computer for data storage display and long-term analysis. Fig. 7 explains the instantaneous speed control method with respect to single setting condition. The method allows the use of a single set of parameters set by the user to vary the speed profile of a build up. The various critical parameters are upper and lower end break limits, observations and correction time, speed increase/decrease %. These are briefly explained below. • Observation time - Time for which end break is to be observed • Correction time - Time for which speed correction is to be done based on the observation. • Maximum and minimum end break limit • Maximum and minimum speed limite • Speed increase and decrease percentage Depending on the number of end breaks and speed during the observation period (reference Fig. 5), speed correction is done in the successive period. There are three possibilities of end breaks occurance here. The conditions explained below provides how the method reacts to these conditions. 1. If End Breaks are within minimum and maximum limit, then speed remains the same as during the observation period. 2. If End Breaks are less than minimum limit, then speed increases from average of speeds during observation time by the % speed increase set. 3. If End Breaks are greater than maximum limit, then speed decrease from average speeds during the observation time by the % speed decrease set. Referring to Fig. 7 if observation period 13 is consideredd, the end breaks (next period) obtains at that period are more than the upper limit (12 EB/100 spdl. Hours) and hence the speed for period 14 is reduced by the set percentage. For the other observation periods, the table below explains the modalities of operation. Fig. 8 explains instantaneous speed control method with respect to multiple setting conditions. The method, allows instead of a single setting provision for various parameters lime upper and lower limits etc., a multiple setting provision. Each setting provision can be provided for different blocks of time/length zones within a build-up (Ref. Fig. 8 for an example) . Each block have a separate set of control settings to operate. This is advantageous over single setting provision for an entire doff. In situations, where in the initial stages of speed profile (for example, normally upto 30 minutes) in which higher end breaks are associated, a higher increase/decrease in percentage may not be wanted where as the same percentage increase/decrease may be the optimum levels for other length/time zones within doff. Hence, a separate setting provision for initial stages may be required and similarly for other time/length zones. It is thus possible by way of the system of the present invention to provide a system and method for controlling breaks and maintaining uniform spinning tension of a longitudinally stretched article in a spinning machine wherein control of end breaks and uniform spinning tension is effected by means collecting and analyzing end break and spindle speed of the said machine continuously and means determining and providing for the spindle speed likely to reduce end breaks. The invention further provides for a closed loop on-line production monitoring system and method wherein spinning machine speed is controlled based on end breakage data. Accordingly, the system of the invention is adapted for the control of the spindle speed based on end breakaging data with for variator driven spinning machines and also the inverter driven spinning machines. We Claim l. An apparatus for controlling breakage of longitudinally stretched articles in a spinning machine comprising : at least one sensor means for sensing process condition/article condition provided at each spinning machine ; each said spinning machine operatively connected to a microprocessor based machine station for acquisition of process condition/article condition data from said sensors ; said machine station operatively connected to a electronic control unit provided to control the spinning machine speed based upon article condition/process condition sensed. 2. An apparatus as claimed in claim 1 wherein said electronic control unit controls said spinning machine speed by pneumatic and/or electrical and/or mechanical means. 3. An apparatus as claimed in claim anyone of claims 1 or 2 wherein said spinning machine comprise variator driven spinning machine ; said process condition/article condition comprise information on end breaks of the stretched article and the spindle speed ; said micro processor based system providing to acquiring information on end breaks and the spindle speed from said sensors which is further transmitted on the said electronic controller unit ; said electronic control unit having means for controlling the variator drive spinning assembly speed based upon the end breakage data via a pneumatic control unit. 4. An apparatus as claimed in anyone of claims 1 to 3 wherein said pneumatic control unit comprise : a pneumatically operating piston which is operatively linked to the variator drive assembly the latter further operatively connected to the tinroller shaft of the spinning machine to control the spinning speed. 5. An apparatus as claimed in claim 4 wherein said pneumatic control unit comprise a solenoid based pneumatic control unit. 6. An apparatus as claimed in anyone of claims 1 or 2 wherein said spinning machine is an inverter driven spinning machine, said processing condition/article condition comprise information on end break of said stretched article and spindle speed ; said microprocessor based system adapted to acquire information on end breaks and spindle speed from said sensors which is further transmitted on to said electronic control unit ; said electronic control unit having means for controlling the speed of the spinning machine based upon the end breakage data. 7. An apparatus as claimed in anyone of claims 1 to 6 wherein said electronic control unit comprise atleast two microcontroller comprising first microcontroller and a second microcontroller each said microcontroller controlled by software in their respective ROMs, said first microcontroller adapted to receive user input through input means and having a non volatile RAM (NVRAM) for storage and means for transferring the same serially to the second controller having RAM for storage thereof, said second controller adapted to acquire information on end break from the machine station and processing and storing the same ; said first controller having means for acquisitions of data from input/output control unit for information on stocks, doffs, tin roller speed and front roller speed ; the second control having means for calculating referred speed and the end break resulting and compare the same with corresponding block setting in the memory ; said first controller adapted to operatively connect to said pneumatic control unit. 8. An apparatus as claimed in claim 7 wherein said first controller comprise means to perform two serial operations comprising bidirectional communication with PC and bidirectional communication with second controller. 9. An apparatus as claimed in anyone of claims 7 or 8 wherein said second controller comprise means to perform two serial operations comprising bi-directional communication with first controller and uni- directional communication with machine station 10 An apparatus as claimed in anyone of claims 1 to 9 wherein said electronic control unit is operatively connected to a personal computer having means for data storage, display and long term advantages. 11 An apparatus for controlling breakage of longitudinally stretched articles in a spinning machine substantially as herein described and illustrated herein. An apparatus for controlling breakage of a longitudinally stretched article in a spinning machine and maintaining uniform spinning tension by varying the spindle speed of the machine with respect to the end breakage levels. The system involves sensor means for sensing process condition/article condition at each spinning machine, microprocessor based machine station for acquisition of process condition/article data from said sensors and a machine station adapted to control the spinning machine speed based on the article condition/process sensed.

Full Text

The present invention relates to a system for controlling breakage of a longitudinally stretched article in
a spinning machine and maintaining uniform spinning tension by varying the spindle speed of the
machine with respect to the end breakage levels.
In order to attain optimum spinning conditions, in which higher production, labour productivity and good
yarn quality are the main requirements, end break levels are to be reduced and maintained so that
higher spindle speeds and other optimum conditions can be arrived at.
An end breakage in spinning is an occurrence in which discontinuity in spinning process is caused due
to a situation when tension placed on the yarn during spinning exceeds the yarn strength. To explain, at
higher spindle speeds, the spinning tension increases and as a result of higher spinning tensions, the
difference between the yarn breaking force and the tension placed one the yarn becomes much less
and therefore the probability of end break increases.
Tension in yarn during spinning occurs due to various conditions such as poor raw material quality, non-
optimised spinning preparatory processes, machinery conditions and various setting parameters of
spinning process, varying ambient conditions and poor material handling.
In our co-pending application No. 1321/Cal/98 there is provided a system for providing the yarn laid-in a
slack form to attain uniform test conditions for yarn in an yarn tensile testing method comprising:
- means to vertically holding the yarn to be tested comprising a top clamp and a bottom clamp and
suction unit loosely holding the leading end of the yarn passing therethrough said top and bottom
clamps, said top clamp being fixed and the bottom clamp movable;
a plunger actuating unit having means for effecting a movement of an actuating member thereof to
thereby pull required yarn length from said suction unit for laying in slack form of the yarn to be tested
therebetween said top and bottom clamp, said bottom clamp having means for clamping said yarn after
said laying in slack form of said yarn and said plunger actuating unit further having means for retracting
said actuuating member thereof to its original position after claiming of said bottom clamp to thereby
provide for slack laying-in of the yarn to be tested therebetween said top and bottom clamps.
Our other co-pending application No. 1322/Cal/98 is directed to a system for constantly measuring
mass variation of a longitudinal material in a continuous process of its manufacture requiring liner
distribution and uniformity comprising:
sensor means to sense a linear mass distribution of the material at the various stages of processing
at the various subsystems;
means to activate the sensor means for acquisition of product status at every sub station;
- means to store the standard parameters of product status at every stage of processing at respective
sub status;
means to analyze and compare the data sensed by said sensor with respect to said standard
parameters;
control unit to generate working status signal to the various subsystems based upon comparative
analysis carried out by said means for analyzing and comparing;
a communication control means interfacing therebetween said means for activating, storing,
analyzing and comparing said sensed data and said control unit and also with the various
subsystems to the control unit for effecting necessary control in processing.
Primary among the various factors which influences and breakage levels is spindle speed of the running
machine and it offers an advantage that this can be successfully varied to control the end breakage
level unlike other factors such as raw material
quality which cannot be altered at the final stages of spinning
processes.
When yarn tension is measured during a yarn package build up
from the beginning to the end of the yarn package while spinning
the yarn, a long-term change in tension between two extremes of
yarn package build up can be noted. At the beginning of yarn
build-up, the spinning tension will be significantly higher than
the end of the build-up. This excess tension in the beginning of
the build up has a negative effect on the yarn quality and on
the running conditions at this phase of the build up.
It is therefore essential to control the tension at the initial
stage of the cop build up inorder to maintain the end breakage
rates uniformly and at a lower level throughout the doff.
In order to atleast reduce the disadvantage of higher spinning
tension at the beginning of the cop build, a 2 stage drive
system available commonly serves the purpose to some extent. Two
stage drive systems use two motors, one running at slow speed
and other at high speed according to the required time for which
these have to operated. This system makes possible the reduction
of speed (and therefore a reduction of the spinning tension to a
normal level) at the beginning of the cop build and at the end.
Accompanying Figure 1 shows the resulting conditions of spinning
tension with such a system.
It is seen from Figure 1 that the excess tension at the
beginning and at the end is eliminated. As a result, the working
performance in spinning is considerably improved due to a
reduction in end breakage rate at these levels. The limitation
as the maximum spindle speed is therefore removed and
consequently the average speed could be increased from the
prevailing level, thus increasing the production of the machine.
A certain disadvantage, with this system, however, is the sudden
surge in spinning tension at the speed change-over point which
results in a change in yarn quality characteristics and spinning
performance at this point. As a result, though the system is an
improvement over the constant speed arrangement, it is not
entirely suitable for very high production spinning.
Extending the concept introduced by the two-stage spinning
process, several advancements took place with the prime
intention of increasing the speed over a definite number of
steps so that the change over of speed is not very abrupt.
One such system is the VPS (Vari Pitch Sheare) drive system. VPS
drives are commonly used and mechanically controlled. In VPS
drive, motor will run at constant speed only. The VPS varies the
speed of ring frame in finite steps by varying the pitch
diameter of the V-belt sheaves. This is automatically done
during working of the ring frame by changing the sheave diameter
from minimum to maximum. The problems associated with VPS is the
range of speed variators limited to only a certain percentage
(for eg. About 25%). Due to various moving parts, the VPS pulley
needs frequent maintenance. However, these are relatively less
costlier.
With variators, speed adjustment is not carried out at the
motor, but by means of adjustable grooved discs in the belt
drive. In the variator, to get change in speed, change in
diameter is effected by shifting the belt with two V-pulleys
each made up by a respective pair of conically faced discs
movable towards and away from each other. The adjustment is
effected usually by a control device acting via pneumatic or
hydraulic pistons and a lever mechanism.
Another development in speed controlled drives for ring frame is
inventer. These are power electronic motor controller and
generally has no moving parts. These are available as part of
ring frames or can be installed separately. The speed of motor
is varied according to the speed setting adjustments programmed.
The motor speed is controlled by controlling the supply
frequency by means of a current controlled frequency converter,
relays, voltage or using binary inputs. Inverters have no speed
limit, but depends on the machine parameters, motors, etc.
Inverters reportedly consume more power and are also relatively
expensive.
It is thus the basic objective of the present invention to
provide an economical system for providing smooth change over of
speed from the start of the doff to the end thereby maintaining
uniform tension in the yarn.
Another object of the present invention reside in that unlike in
all the known methods described earlier, wherein the speed
profile is defined by the user according to information on end
breakages available with line to have a system wherein the
change in speed is effected based on information obtained on
line about the end breakages.
Yet further object of the present invention is to provide a
system wherein the end breakages could be controlled to a large
extent by providing means for analyzing instantaneous end break
and speed data and having means for adjusting spindle speed
accordingly based upon said end breakage data.
Yet further object of the present invention is to provide an
improved method for controlling breakages of the stretched
article utilizing the system of the invention.
Yet further object of the present invention is to provide a
closed loop control system to monitor and control the end breaks
effectively.
Thus according to the present invention there is provided a
system for controlling breakage of longitudinally stretched
articles in spinning machines comprising :
at least one sensor means for sensing process condition/article
condition provided at each spinning machine ;
each said spinning machine operatively connected to a
microprocessor based machine station for acquisition of process
condition/article condition data from said sensors ;
said machine station operatively connected to a electronic
control unit provided to control the spinning machine speed
based upon article condition/process condition sensed.
In accordance with one aspect of the present invention the
system for controlling breakage of longitudinally stretched
articles in variator driven spinning machines comprise
said process condition/article condition comprising information
on end breaks of the stretched article and the spindle speed ;
said micro processor based system providing to acquiring
information on end breaks and the spindle speed from said
sensors which is further transmitted to the said electronic
control unit ;
said electronic control unit having means for controlling the
variator drive spinning assembly speed of the variator driven
spinning machine based upon the end breakage data via a
pneumatic control unit.
In accordance with another aspect of the present invention the
system for controlling breakage of longitudinally stretched
articles in an inverter driven spinning machine comprise
said processing condition/article condition comprising
information on end break of said stretched article and spindle
speed ;
said microprocessor based system adapted to acquire information
on end breaks and spindle speed from said sensors which is
further transmitted on to said electronic control unit ;
said electronic control unit having means for controlling the
speed of the inverter driven spinning machine based upon the end
breakage data.
According to yet further aspect the invention provides for
improvement in the method of controlling end breakage of
longitudinally stretched articles in a spinning machine
utilizing the system disclosed above comprising
acquiring end break data from the machine station ;
calculating the end breakage rate (EBR) after an observation
cycle ;
comparing the calculated EBR with standard values ;
effectuating speed up or down control as required ;
effectuating necessary changes in quantum of speed increase or
decrease based on the input entry and speed input from machine ;
transferring of control to pneumatic control unit and finally
execution of controller.
The present invention thus provides for the possibility of
arranging a selective and continuous speed adjustment in
spinning machine for the complete build-up. In this way, optimum
conditions of spindle speed can be obtained such that,
throughout the buildup, a practically constant spinning tension
is available. Such a trace is shown in the accompanying figure
2.
In the above system of the invention by way of an on-line
monitoring system information is acquired from each and every
spindle in a ring spinning machine by sensor means and in a
controlled manner for improvement of machines productivity.
In particular, each spinning machine consists of a set of
sensors which are the components which collect information such
as end breaks, speed, production etc. Informations from these
sensors are connected to a "Machine Station". The machine
station is controlled by a microprocessor which accepts data
from the sensors. Each machine has a separate machine station.
The machine stations are connected to a central unit (also
called control unit) which has input / output devices for
interaction with the user. The machine stations are periodically
called up by the central unit for obtaining the information.
The electronic control unit of the system is operatively linked
to the machine station of the on-line monitoring system to
collect information on end breaks periodically. This information
is subsequently processed by the system and acted upon.
The details of the invention its objects and advantages will be
further apparent from the non-limiting exemplary embodiments of
the system of the invention discussed hereunder with reference
to accompanying figures wherein
Fig. 3A shows a speed control device for variator driven
spinning machines.
Fig. 3B shows schematically the construction of the pneumatic
control unit.
Fig. 4 explains a device to control speed according to the
methods explained in Figs. 7 and 8.
Fig. 5 shows a speed control device for inverter driven spinning
machines
Fig. 6 shows schematically the construction of the electronic
control unit used in the system of the invention.
Fig. 7 explains the instantaneous speed control method with
respect to a single setting condition.
Fig. 8 explains the instantaneous speed control method with
respect to multiple setting condition.
Reference is first invited to Fig. 3A which shows a speed
control device for variator driven spinning machines. Variator
drive assembly (13), consists of taper shieves (5) and belt (6).
The top variator drive assembly is connected to a motor (1)
through motor shaft (2) and bottom of variator drive assembly is
connected to tin roller (4) through tin roller shaft (3) . Input
to the variator drive comes from a variator cylinder (7) which
is pneumatically operated by a pneumatic control unit (8). The
pneumatic control unit (8) gets the required signal from
Electronic control unit (9) gets information from various sensor
outputs (10) (one such sensor is a sensor (12) for measuring
spindle speed) and machine inputs (11) programmed by the user.
Reference is now invited to Fig. 3B which shows schematically
the pneumatic control unit comprising of the two single solenoid
valves and flow onto valve alongwith the pneumatic circuit
diagram as illustrated.
Speed control is effected by movement of the piston. Air flow
into the piston is controlled by solenoid valves NC 1 and NC 2
as shown below :
Referring to Fig. 3A spindle speed is varied by using the taper
shieve pulleys (5) fixed on the tin roller shaft (3) and motor
shaft (2). The ratio between the revolutions of these two shafts
is governed by the position of the belt (6) running between the
pulleys. By adjusting the position of the belt (6) on motor
shaft pulleys (5.1), the transfer ratio can be adjusted. With
different transfer rations, the required tin roller shaft speed
is achieved. The piston (14) in the variator cylinder controls
the position of the taper sheives (5.1 & 5.2). the position of
the pistorn (14) is electronically controlled and the speed at
which the machine is to be run as per the programmed settings
(11) threads in electronic speed control unit (9) . Also, in case
of frequency fluctuations, the speed of the tin roller shaft
vary, which is monitored by tin roller shaft (12) and the sensor
input is communicated to electronic control unit (9) which then
effectuates necessary correction signals.
The above speed control device (5) works in tandem with an online
production monitoring system (2) to effectively vary the
spindle speed of the spinning machine (1) as seen from Fig. 4.
The on-line production monitoring system (2) has machine
stations (3) available for every spinning machine. The machine
station (3) collects informations such as spindle speed and end
breaks from machine and passed on to a control unit (4) which
consolidates the information and presents the report to the
user. The device (5) collects these end breaks and spindle speed
information directly from machine station (3) and alters the
spindle speed of spinning machine after analysing the data based
on the methods explained sufficiently in detail in Figs. 7 and
8. The device (5) explained here can be either variator driven
as explained in Fig. 3A and 3B or inverter driven as explained
in Fig. 5.
Fig. 5 shows a speed control device for inverter drivers
spinning machines. The motor (1) gets the speed signal from
inverter (2) which can be of any type through an electronic
control unit (3) . The electronic control unit (3) gets sensor
inputs (5) from machine, and machine input (4) set by user to
give necessary speed signal to inverter (2).
Reference is now invited to the illustration in accompanying
Fig. 6 when the construction detail of the electronic control
unit are provided in the form of a functional schematic diagram.
The electronic control unit consists of two Micro controllers
controlled by the software in their respective ROMs. One of the
micro controllers MC1 receives user input such as settings from
the keyboard through a Keyboard / Display controller and
transfers serially to the other controller MC2. The same
settings are stored in a Non-volatile RAM (NVRAM) controller.
MC2 reads the setting and stores it in the RAM sequentially.
End break information from the machine station (of the on-line
monitoring system) is acquired and processed by the micro
controller MC2 and stored in the RAM memory.
Information on stops, doffs, tinroller speed and front roller
speed which is necessary for the functioning of the device are
obtained by Input/Output control unit and transferred to MC1.
After completion of the observation cycle, Controller 2 (MC2)
calculates the reference speed and also the EBR. Now EBR is
compared with the corresponding block settings available in the
memory and the speed is transferred serially to the Controller 1
(MC1), whereafter the controller bypasses all the pattern
control and the control is switched to the new speed calculated
and assigned by the Controller 2 (MC2).
In particular, in the electronic control unit the said
Controller 1 (MC1) performs two serial operations a)
Communication with the PC (Bi-directional) and b) Communication
with the Controller 2 (MC2) (Bi-directional), while Controller 2
(MC2) performs two serial operations a) Communication with
Controller 1 (MC1) (Bi-directional) and b) Communication with
Machine Station (Unidirectional).
The above functional operation is the same for both Inverter
based and variator based systems. The difference only being in
the mode of effecting the change in speed. In the case of
Inverter, MC1 gives the change signal through a Digital to
analog converter (DAC).
In case of Variator based system the speed change will be
effected through a pneumatic control unit.
Optionally, the electronic control unit can be connected a
personal computer for data storage display and long-term
analysis.
Fig. 7 explains the instantaneous speed control method with
respect to single setting condition. The method allows the use
of a single set of parameters set by the user to vary the speed
profile of a build up. The various critical parameters are upper
and lower end break limits, observations and correction time,
speed increase/decrease %. These are briefly explained below.
• Observation time - Time for which end break is to be observed
• Correction time - Time for which speed correction is to be
done based on the observation.
• Maximum and minimum end break limit
• Maximum and minimum speed limite
• Speed increase and decrease percentage
Depending on the number of end breaks and speed during the
observation period (reference Fig. 5), speed correction is done
in the successive period. There are three possibilities of end
breaks occurance here. The conditions explained below provides
how the method reacts to these conditions.
1. If End Breaks are within minimum and maximum limit, then speed
remains the same as during the observation period.
2. If End Breaks are less than minimum limit, then speed
increases from average of speeds during observation time by
the % speed increase set.
3. If End Breaks are greater than maximum limit, then speed
decrease from average speeds during the observation time by
the % speed decrease set.
Referring to Fig. 7 if observation period 13 is consideredd, the
end breaks (next period) obtains at that period are more than
the upper limit (12 EB/100 spdl. Hours) and hence the speed for
period 14 is reduced by the set percentage. For the other
observation periods, the table below explains the modalities of
operation.
Fig. 8 explains instantaneous speed control method with respect
to multiple setting conditions. The method, allows instead of a
single setting provision for various parameters lime upper and
lower limits etc., a multiple setting provision. Each setting
provision can be provided for different blocks of time/length
zones within a build-up (Ref. Fig. 8 for an example) . Each block
have a separate set of control settings to operate. This is
advantageous over single setting provision for an entire doff.
In situations, where in the initial stages of speed profile (for
example, normally upto 30 minutes) in which higher end breaks
are associated, a higher increase/decrease in percentage may not
be wanted where as the same percentage increase/decrease may be
the optimum levels for other length/time zones within doff.
Hence, a separate setting provision for initial stages may be
required and similarly for other time/length zones.
It is thus possible by way of the system of the present
invention to provide a system and method for controlling breaks
and maintaining uniform spinning tension of a longitudinally
stretched article in a spinning machine wherein control of end
breaks and uniform spinning tension is effected by means
collecting and analyzing end break and spindle speed of the said
machine continuously and means determining and providing for the
spindle speed likely to reduce end breaks. The invention further
provides for a closed loop on-line production monitoring system
and method wherein spinning machine speed is controlled based on
end breakage data. Accordingly, the system of the invention is
adapted for the control of the spindle speed based on end
breakaging data with for variator driven spinning machines and
also the inverter driven spinning machines.
We Claim
l. An apparatus for controlling breakage of longitudinally stretched
articles in a spinning machine comprising :
at least one sensor means for sensing process
condition/article condition provided at each spinning
machine ;
each said spinning machine operatively connected to a
microprocessor based machine station for acquisition of
process condition/article condition data from said sensors ;
said machine station operatively connected to a electronic
control unit provided to control the spinning machine speed
based upon article condition/process condition sensed.
2. An apparatus as claimed in claim 1 wherein said electronic control
unit controls said spinning machine speed by pneumatic and/or
electrical and/or mechanical means.
3. An apparatus as claimed in claim anyone of claims 1 or 2 wherein
said spinning machine comprise variator driven spinning
machine ;
said process condition/article condition comprise information
on end breaks of the stretched article and the spindle speed ;
said micro processor based system providing to acquiring
information on end breaks and the spindle speed from said
sensors which is further transmitted on the said electronic
controller unit ;
said electronic control unit having means for controlling the
variator drive spinning assembly speed based upon the end
breakage data via a pneumatic control unit.
4. An apparatus as claimed in anyone of claims 1 to 3 wherein said
pneumatic control unit comprise :
a pneumatically operating piston which is operatively linked
to the variator drive assembly the latter further operatively
connected to the tinroller shaft of the spinning machine to
control the spinning speed.
5. An apparatus as claimed in claim 4 wherein said pneumatic control
unit comprise a solenoid based pneumatic control unit.
6. An apparatus as claimed in anyone of claims 1 or 2 wherein said
spinning machine is an inverter driven spinning machine, said
processing condition/article condition comprise information on
end break of said stretched article and spindle speed ;
said microprocessor based system adapted to acquire
information on end breaks and spindle speed from said sensors
which is further transmitted on to said electronic control
unit ;
said electronic control unit having means for controlling the
speed of the spinning machine based upon the end breakage
data.
7. An apparatus as claimed in anyone of claims 1 to 6 wherein said
electronic control unit comprise
atleast two microcontroller comprising first microcontroller
and a second microcontroller each said microcontroller
controlled by software in their respective ROMs, said first
microcontroller adapted to receive user input through input
means and having a non volatile RAM (NVRAM) for storage and
means for transferring the same serially to the second
controller having RAM for storage thereof, said second
controller adapted to acquire information on end break from
the machine station and processing and storing the same ;
said first controller having means for acquisitions of data
from input/output control unit for information on stocks,
doffs, tin roller speed and front roller speed ;
the second control having means for calculating referred speed
and the end break resulting and compare the same with
corresponding block setting in the memory ;
said first controller adapted to operatively connect to said
pneumatic control unit.
8. An apparatus as claimed in claim 7 wherein said first controller
comprise means to perform two serial operations comprising
bidirectional communication with PC and
bidirectional communication with second controller.
9. An apparatus as claimed in anyone of claims 7 or 8 wherein said
second controller comprise means to perform two serial
operations comprising bi-directional communication with first controller and uni-
directional communication with machine station
10 An apparatus as claimed in anyone of claims 1 to 9 wherein said electronic
control unit is operatively connected to a personal computer having means for
data storage, display and long term advantages.
11 An apparatus for controlling breakage of longitudinally stretched articles in a
spinning machine substantially as herein described and illustrated herein.
An apparatus for controlling breakage of a longitudinally stretched article in a spinning
machine and maintaining uniform spinning tension by varying the spindle speed of the
machine with respect to the end breakage levels. The system involves sensor means for
sensing process condition/article condition at each spinning machine, microprocessor
based machine station for acquisition of process condition/article data from said sensors
and a machine station adapted to control the spinning machine speed based on the article
condition/process sensed.

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Patent Number

211012

Indian Patent Application Number

1320/CAL/1998

PG Journal Number

42/2007

Publication Date

19-Oct-2007

Grant Date

16-Oct-2007

Date of Filing

28-Jul-1998

Name of Patentee

PREMIER POLYTRONICS LTD.

Applicant Address

185, A. T. D. STREET, RACE COURSE, COIMBATORE-641 018, STATE OF TAMILNADU, INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	SHEKARIPURAM NARAYANASWAMY RAMACHANDRAN	5, KHAIRU PLACE, CALCUTTA-700 072,
2	APPAVU PAVENDHAN	FLAT NO. 3, ANUGRAHA APARTMENTS, PHASE-I, KAMARAJAR ROAD, PEELAMEDU, COIMBATORE-641004
3	KARUPPASWAMY SUKUMAR	10-D-1, LBHARATHINAGAR, GANDHIJI ROAD, PODANUR, COIMBATORE-641023
4	SRINIVASAN THIRUPATHI	20-A, PERIYAR RAMASAMY STREET, PN PUDUR, COIMBATORE-641041

PCT International Classification Number

D 01 H 13/20

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA