FIELD OF THE INVENTION
The present invention relates to a system for automated coil transfer car for transporting Hot Rolled (HR) Coils from the Hot strip Mill (HSM) for processing in subsequent stages, and a control system thereof for operation in Cold Rolling Mill (CRM) complex in Steel Plants to achieve desired overall productivity. More particularly, the invention is directed to developing a system for automated coil transfer car that matches with the degree of automation through out the processes stages in CRM complex, aimed at achieving excellent quality and maximum productivity. The Automated transfer cars adapted to achieve maximum productivity according to the present invention is provided with wireless central control by a Human machine Interface (HMI) in the pulpit and also the provision for transfer of control to Local controls by means of Local Push Button Stations (LPBS) at selective locations along the transfer track line. The system of control of the various devices and drives of the automated coil transfer car wherein the Master controller is with HMI and the control can be transferred from the HMI to any of the LPBS after receiving request for same from the LPBS, whereby only one control entity, either HMI or LPBS, controls the transfer car at a time. The automated transfer car of the present invention and control system thereof, is directed to include unique features such as 150 Tonne carrying capacity, high speed of about 60mpm, long travel length 230 meters, high ambient operating temperature such as of 50 deg C and transfer of coils at as high as 120 deg C. which enable maximizing productivity with minimum operator intervention, having wide industrial application and economy in production.
BACKGROUND ART
The Cold Rolling Mill (CRM) in steel plants produces Cold Rolled Steel sheet coils mainly for use in the Automobile Industry. The CRM Complex consists of 7 highly automated process lines, which transform the incoming Hot Rolled (HR) Coil from the Hot Strip Mill (HSM), into a fine Cold Rolled Sheet.
The HR Coils produced in the HSM are further treated with acid and cleaned in the Continuous Pickling Line (CPL) and their thickness is cold reduced in the Compact Cold Mill (CCM) by a Cold Rolling Process. The CR coils so produced then pass through the Electrolytic Cleaning Line (ECL) where they are washed with electrolyte to remove residue oil and iron fines. They are then Annealed (Heat Treated) in the Batch Annealing Furnaces (BAF) to impart suitable metallurgical properties, after which the coils are


passed through the Skin Pass Mill (SPM) to impart target roughness and uniform mechanical properties to the sheet. They are then taken through the Recoiling and Inspection Line (RCL), where the sheet is inspected for surface defects, and finally packed for dispatch in the Automatic Packaging Line (APL).
The transfer cars are supposed to serve the purpose of handling the HR coils from the HSM to the different subsequent stages in different bays along the entire CRM Complex.
In the CRM complex for processing HR coils through the above-mentioned stages, the applicants manufacturing facility having high degree of automation aimed at achieving excellent quality associated with maximum productivity. The coils from ECL are transferred to the BAF for Annealing. After Annealing, they are transferred to the Coil Cooling & Storage Unit (CCSU) where they are stored, and then transferred to the SPM. These steps involve tremendous amount of coil handling occurring between the ECL and the SPM.
The length of the bay connecting the ECL (Exit Side) and SPM (Entry Side) is about 230 meters. As mentioned earlier, a lot of coil handling takes place in this bay. The applicants manufacturing facility experienced that conventional Transfer Cars have a number of functional limitations to match the material handling requirement for optimization of productivity of the plant, and there would be too much reliance on the efficiency of a Human Operator. The Operator in the Control Pulpit in a conventional set up verbally communicates to the shop floor operator regarding the final location of the Transfer Car, and the destination would be reached after much trial and error, consuming much time and still has to accommodate a compromise between the desired and actual location. Likewise, the dependency on Crane movement would also increase in the bay to support the desired productivity.
The Transfer Cars in most steel plants are either conventional type, which include a simple forward-reverse motion control with a suitable motor-gearbox drive and power supply with conventional bus bars or a cable reeling drum. Alternatively, the car is powered by Diesel Generator (DG) Set, wherein the Transfer Car is driven by a driver manually.


It was further experienced that in the CRM complex, the BAF consisting of 40 Bases for Batch Annealing and the CCSU consisting of 72 bases for final cooling. The Transfer Car would thus need to transfer the CR coils from the ECL to the BAF for Annealing, from BAF to the CCSU for storage, and from CCSU to the SPM.
There has been therefore a continuous need in the CRM complex for conversion of HR coils from HSM to the Skin Passed coils in SPM and then finally to the packaging line. The automation of transfer cars of adequate carrying capacity and operational control had to be achieved to meet the quality and productivity criteria by the process performance in stages, replacing operation of conventional Transfer Cars having limited performance, productivity and too much reliance on the manual operators. It has also been felt that centralized master control in the Pulpit combined with distributed local control Push button stations at strategic locations on site would lead to the convenient taking of optimistic decisions regarding the Transfer Car movement considering the long length of travel. The transfer cars need to be developed for high capacity, high speed, high degree of automation, less dependence on manual operation and simple, accurate, safe yet easy to operate.
Thus the need for uncompromising approach to productivity issues, led to developing the novel Transfer Car with Automation system for operational control and safety, with minimum operator interference. The highly automated Transfer Cars would thus meet the requirement of connecting the exit side of ECL to the entry side of SPM to simplify the complicated and time consuming coil handling process and achieve maximum productivity that can be delivered through the interconnecting process lines the ECL, the BAF & the SPM, and would ensure wide application of such automated handling facility in the automated production lines in large integrated steel industry.
OBJECTS OF THE INVENTION
It is thus the basic object of the present invention to provide for automated steel coil Transfer Cars for CRM complex to meet the quality and productivity requirement of the processes involved in conversion of the HR coils to the CR coils in different stages of processing from exit of ECL up to the SPM entry to favor feeding thereafter at desired rate to recoiling and inspection (RCL) and finally automatic packaging line (APL), and a


control system to optimize the performance of the Coil handling system with minimum operators involvement.
A further object of the present invention is directed to the automated transfer car and a control system thereof for operation in Cold Rolling Mill (CRM) complex in Steel Plants, directed to achieve performance to match with the degree of automation through out the processes stages in CRM complex, aimed at achieving excellent quality and maximum productivity.
A further object of the present invention is directed to the automated transfer car and a control system thereof, wherein said automated Transfer cars are adapted to achieve capacity of 150 tonnes and adapted to travel over the length of the track spanning over from exit of ECL to the SPM entry side, either in forward or backward direction, with control of desired speed and stop/start with selective precision/accuracy at desired location, including programmable stops at strategic locations.
A further object of the present invention is directed to the automated transfer car and a control system thereof, wherein the transfer car is adapted to operate safely at a speed range of 60mpm to 30 mpm during automatic mode and 30mpm for inching operation in maintenance mode, bypassing all interlocks and capable to transfer coils at an operating temperature range of 120°C and at ambient temperature of 50°C.
A still further object of the present invention is directed to the automated transfer cars and a control system thereof, wherein said transfer cars are adapted to travel, either forward or backward, at controlled speed through the various stages from exit of ECL through the Batch Annealing Furnaces (BAF), Coil Cooling and Storage Unit where they are stored and then to Skin Passing Mill (SPM) and/or stop at defined programmable locations, according to the need of the interconnecting production process sequence/lines directed to favor maximum productivity.
A still further object of the present invention is directed to the automated transfer car and a control system thereof, wherein said Automated Transfer cars are wirelessly controlled centrally by a Human Machine Interface (HMI) located in the Control Pulpit combined with distributed local control e.g. Local Push Button Stations at five selective


locations while ensuring that only one entity either the HMI or any one of the LPBS controls the transfer car at a time.
Another object of the present invention directed to the automated transfer car and a control system thereof, wherein, all control signals from the transfer cars are transmitted through wireless system, adapted to communicate between a Master antenna on the transfer cars and a Slave antenna mounted in the pulpit and said control system also ensures trouble free communication between the Programmable Logic Controller (PLC) in the pulpit and the devices on the transfer cars.
According to yet another object of the present invention the automated transfer cars for coil transfer in the CRM complex, are provided with inbuilt devices viz LASER scanner to detect any object on track and to stop car, door limit switches for track cross over at selective locations through doors on fencing, Hooter and blinker, emergency stop facility, end stoppers/end limit switches etc. to ensure high level of operational safety.
A still further object of the present invention is directed to the automated transfer car and a control system thereof, wherein the transfer car is adapted to be operated in 3 modes viz. Automatic Mode, Semi-automatic mode and Manual Mode.
Another object of the present invention is directed to the automated transfer cars and a control system thereof, wherein the operator intervention is minimum such that the requirement of manpower for controlling the transfer car movement over the entire stretch is limited to 1 person in the pulpit, reducing the requirement of four operators and four relievers on each shift, one for pulpit control and other three for the local control.
SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided a system for automated coil transfer car for productivity improvement in cold rolling mill complex comprising:
control means comprising a central control unit with human machine interface (HMI) in the control pulpit and selectively disposed local control units at strategic locations along


its travel path, wherein the master control is with the HMI and the control adapted to be
transferred from said HMI to any LPBS as and when such instruction is received from said
HMI;
Means for wireless transfer of signal there between said transfer car and said central
control unit;
Shrouded underground bus bar power and control supply means adapted to operate and
control the equipments on the transfer car;
Means to selectively control the movement of the transfer car and also its strategic stoppage at pre selected locations;
A PLC based transfer car speed control and setting provision; and
Means to selectively operate the transfer car in anyone of (a) automatic mode (b) semi¬automatic mode and (c) manual mode as may be desired.
In accordance with a preferred aspect of the invention in the system for automated coil transfer car for productivity improvement in cold rolling mill complex above there is provided safety features comprising selectively anyone or more of the following:
Laser scanner adapted to stop the transfer car as and when any person or object is spotted in front of the car;
Fencing of the entire area of travel of the transfer car with door limit switches at appropriate locations adapted such that car stops once a door is opened due to the activation of said door limit switch;


Audio-visual alarm means adapted to indicate the starting and stopping of the car at various locations;
Emergency stop facility; and
End Limit switches coupled with Mechanical end stoppers adapted to ensure stoppage of the car within safe and restricted area.
Advantageously, the system for automated coil transfer car for productivity improvement in cold rolling mill complex of the invention is adapted for high capacity 150 tonnes, high speed 60 mpm, long transfer length 230 meters, high ambient operating temperature 50 deg C and transfer of coils of temperature as high as 120 deg C.
In accordance with a preferred aspect in the system for automated coil transfer car for productivity improvement in cold rolling mill complex the same comprises five local push button stations (LPBS) mounted at strategic locations.
According to another aspect in the system for automated coil transfer car for productivity improvement in cold rolling mill complex of the invention the communication is between a master antenna on the transfer car and a slave antenna mounted in the pulpit whereby a trouble free communication is established between the Programmable Logic Controller (PLC) in the pulpit and the devices in the Transfer Car.
According to another aspect in the system for automated coil transfer car for productivity improvement in cold rolling mill complex one set of bus bars carries the power supply for the motors from the frequency drive and the other set carries the control power supply for the brakes and other devices on the transfer car.


According to yet further aspect in the system for automated coil transfer car for productivity improvement in cold rolling mill complex of the invention as above , the door limit switches are adapted to be deactivated from the HMI in the Pulpit as and when required through secured password protected operation.
In accordance with yet another preferred aspect of the invention the system for automated coil transfer car for productivity improvement in cold rolling mill complex of the invention comprises emergency stop push buttons provided on the transfer car, on each of the LPBS and also on the HMI in the pulpit which are all hardwired directly to the Controller to enable immediate stoppage of the Transfer Car during an emergency.
Advantageously also the system for automated coil transfer car for productivity improvement in cold rolling mill complex includes programmable stops adapted to stop at various strategic locations with high stoppage accuracy wherein preferably proximity switches are provided at such locations and the position is selected from the HMI or any of the LPBS if authorized and the car is thus adapted to move at specified locations and stops.
According to a further aspect the system for automated coil transfer car for productivity improvement in cold rolling mill complex of the invention comprises encoder with Profibus connectivity whereby the position of the transfer car in meters from the datum position (ECL) is visible in the HMI and is updated continuously.
Importantly also in the system for automated coil transfer car for productivity improvement in cold rolling mill complex of the invention there is provided PLC based system adapted to control automation and drive of the car.


BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
Figure 1: is the illustration of the process flow chart for the basic processes involved and their sequences and interdependence in a conventional Cold Rolling Mill Complex for conversion of HR coils from HSM to CR coils, in large steel plants.
Figure 2: is the schematic illustration of the schematic layout of the major process lines in CRM Complex, showing the line/area of movements for the automated transfer cars according to the invention.
Figure 3: is the illustration of the schematic 3-dimensional view of the automated transfer cars of the present invention with the coils loaded on it.
Figure 4: is the illustration of the screen shot showing movement/location of both the transfer cars in the HMI Screen, the location of Pulpit and Individual five numbers of LPBS, with respect to the Layout of the Batch Annealing Facility in CRM complex.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURES
The present invention relates to an automated coil transfer car for the CRM complex in steel plants, more particularly, said transfer car and its advanced speed and set point control system is unique and capable to deliver optimum performance with respect to speed and selective stop precisely at the desired location through a HMI based centralized control from pulpit and also selective Local control from local push button stations (LPBS) mounted at strategic locations through out the entire stretch of 230 meters length of travel from exit of ECL(Electrolytic Cleaning Line) to entry of SPM(Skin Pass Mill). These transfer cars are adapted to be operated in three modes viz.: Auto, semi Auto and manual modes. The CRM Complex that is fully automated for different process stages in the conversion of HR coils in to CR coils, rolled, inspected and finally packed for dispatch, ensuring excellent quality and maximum productivity of the rolled and heat treated steel sheets/coils, are facilitated in terms of transporting the coils through the various stages by means of the automated coil transfer cars according to the


present invention, capable to deliver high speed associated with sophisticated wireless control from centralized pulpit as well as the distributed location based control from the selective LPBS, in order to optimize and synchronize the production-operation-material movement requirements for desired high productivity in CRM complex.
Reference is first invited to the accompanying Figure 1 that illustrates the process flow chart for the various process steps and their sequence of occurrences in the CRM complex. It is clearly apparent from the process flow chart in said Figure 1 that the Automated transfer cars operatively communicate in the functional area of ECL exit to SPM entry covering 230 meters length such that said transfer cars with coils mounted on it moves on track, either in forward or backward direction, passing through the BAF and the CCSU areas with satisfactory, reliable and safe control of desired speed and stop/start with selective precision/accuracy at desired location, including programmable stops at strategic locations, to be moved finally to the recoiling and inspection after the skin pass and then sent for final packaging.
Reference is now invited to the accompanying Figure 2, is the schematic illustration of the layout of the CRM complex, highlighting the area of operation of the automated transfer car of 150 Tonne capacity facilitating precise and faster yet safe transportation of the CR coils to the BAF bay from ECL exit to SPM entry covering 230 meters span. The Layout details of Figure 2 when interpreted with reference to the process steps and sequence in the accompanying Figure 1, it may be clearly envisaged that the automated production line require the benefits derived from the automated material handling and its precision HMI/LPBS based control through PLC and other control devices, to meet the objective of process optimization and maximization of productivity with minimum operator interference.
As already discussed, the HR Coils are treated with acid & cleaned in the Continuous Pickling Line (CPL) and their thickness is reduced in the Compact Cold Mill (CCM) by a Cold Rolling Process. They then pass through the Electrolytic Cleaning Line (ECL) where they are washed with electrolyte to remove residue oil and iron fines. They are further Annealed (Heat Treated) in the Batch Annealing Furnaces (BAF) to impart suitable metallurgical properties, after which the coils are passed through the Skin Pass Mill (SPM) to impart target roughness and uniform mechanical properties to the sheet. They are then taken through the Recoiling and Inspection Line (RCL), where the sheet is


inspected for surface defects, and finally packed for dispatch in the Automatic Packaging Line (APL).
The coils from ECL are transferred to the BAF for Annealing. After Annealing, they are transferred to the Coil Cooling and Storage Unit (CCSU) where they are temporarily stored, and then transferred to the SPM. Frequent and repetitive coil handling is necessitated between the ECL and the SPM, either in forward or backward direction as needed. The system for automated control for two highly automated Transfer Cars connecting the exit side of ECL to the entry side of SPM has been successfully implemented according to the present invention, to simplify the complicated and time consuming coil handling process and achieve Maximum Productivity ensured through the interconnecting process lines such as the ECL, the BAF and the SPM, in the CRM complex.
Reference is now invited to the accompanying Figure 3 that illustrates the 3-dimensional view of the automated transfer cars of the present invention schematically with the coils loaded on it, suitably held in position on car during transit. The car is designed for a carrying capacity of 150 Tonne of rolled coils and self propelled with electrical drive motor in the high speed ranging a maximum of 60 mpm(meters per minute) to the lowest inching operation in maintenance mode at 30mpm. The transfer car of the invention is further adapted to operate transferring coils at a high temperature in the range of 120°C and capable to operate satisfactorily and with desired reliability at high ambient temperature of 50°C. The automated transfer cars of the invention and the system of control thereof for desired speed and precise stop at desired location/s is achieved for the CRM complex over a bay length of 230meters. The cars are capable to carry at least 5 HR/CR coils at a time secured on the car frame to enable favored ease of handling and safe transportation from one process stage to another, in forward or backward movement. Two transfer cars are dedicated to cater to each row of the BAF facility on either side of the longitudinal bay track (as shown in the schematic layout in Figure 3 and also position of each car viewed in the HMI screen in Figure 4) for feeding batches in sequence for optimum utilization of facilities. The cars are provided, as a safety measure, with end stoppers and End limit switches, as identifiable in the accompanying Figure 3, which ensure stopping the cars well within the restricted area and also they are provided with the emergency stop facility which can be functional in any of the auto, semi-auto or the manual mode of operation of the control system for the transfer cars.


It has been explained that after the HR coils are treated with acid and cleaned in the continuous pickling line (CPL), their thickness is reduced in the Compact Cold Mill (CCM) by Cold rolling process. The CR sheets are then washed with electrolyte to remove residue oil and iron fines in Electrolytic Cleaning Line) ECL. The coils are then required to be heat treated/annealed in the batch annealing furnaces (BAF) to impart suitable metallurgical properties, after which the coils are passed through the Skin Pass Mill to impart desired surface roughness and uniform mechanical properties to the sheet. They are then taken through the Recoiling and Inspection line (RCL) for detection of presence of surface defects, if any, and then finally packed for dispatch in the automatic packaging line (APL). Thus the CRM complex involves the process stages which require handling of batches of coils in selective speed of handling and sequencing of batches and holding at each stage for desired time duration for the process to be carried out at that stage, satisfactorily maintaining defined variable process parameters. The BAF consist of 40 bases for Batch Annealing and the CCSU consists of 72 bases for final cooling, where from the stored coils are sent to SPM. The control of the Transfer cars are therefore critical in terms of matching speed of movements and precisely locating the batch of coils with respect to the requirements of optimum process performance in a stage and ensuring quality end product at less cost in a simple manner with enhanced productivity and less operators interference. Thus the control aspect of the automated transfer cars of the invention is of immense importance, reducing too much reliance on human performance.
Reference is now invited to accompanying Figure 4, which illustrates the screen shot showing movement/location of both the transfer cars in the HMI Screen, the location of Pulpit and individual five numbers of LPBS, with respect to the Layout of the Batch Annealing Facility in CRM complex. It is already discussed that the control system for the transfer cars are executed in three options viz. Automatic, Semi-automatic and manual. The Control system comprise both centralized control from pulpit involving the HMI console or the control may be optionally combined with distributed local control from any of the five respective Local Push Button Stations, mounted at strategic locations. The concept of transfer of control is a unique feature for the present invention whereby the Master control with the HMI is selectively transferred to any of the five LPBS for local control on demand for accuracy in maneuvered operation or precise stoppage of the vehicle in transit at a desired location, during forward or in reverse direction of travel, for


the substantially long stretch of travel. The control is thus possible to ensuring either the centralized control from pulpit through HMI or any one of the LPBS may be implemented at a time. The accompanying Figure 4, provides the HMI screen mimic for the system of control of the transfer cars wherein the location of pulpit and the five independent LPBS are shown with respect to the 230meters length of car travel in CRM bay between ECL and SPM, for selective control on operating parameters to control movements as well as the precise stoppage of car at desired location. The control is further transferable from the HMI at pulpit to any of the five LPBS through the corresponding proximity switch, when such control is requested from the LPBS.
The transfer cars of the invention are adapted to be operated in three modes viz the auto mode, semi-auto mode or the manual mode. The transfer of control from HMI to LPBS is established and implemented through proximity switches adjacent to any of the corresponding five LPBS. All control signals from the transfer cars are transferred through wireless system, adapted to communicate between a Master Antenna on the transfer car and a slave antenna mounted in the pulpit, such as to ensure trouble free communication of message/command between the Programmable Logic Controller (PLC) in the pulpit and the different devices on the Transfer car. The salient aspects the transfer cars according to the present invention and the automated control thereof for optimized performance of the system in the CRM complex in steel plants are as follows:
a. Two transfer cars have been developed for desired controlled operation having
carrying capacity of 150Tonne, Max. Travel speed of 60mpm and min. inching
speed of 30mpm in maintenance mode, length of travel of 230 meters covering
exit of ECL to the entry side of SPM. The cars are adapted to operate at high
ambient temperature of 50°C and transfer of coils at a temperature as high as
120°C.
b. The transfer cars are controlled for coil movement involving PLC based centralized
HMI interfaced control from pulpit as well as distributed control from the five LPBS
at strategic locations, on demand for better accuracy in control/precise stoppage
along the long length of travel, as and when needed. Thus only one entity, either
the HMI or any one of the LPBS control the transfer cars at a time.


c. Programmable stops at selected strategic locations within the 230 meters stretch
of travels, with high accuracy of stoppage, being operatively controlled by
corresponding Proximity switches at these locations. The position is selected from
the HMI or any of the LPBS, when authorized, such that the car moves to the
predetermined/programmed location and stops.
d. The transfer car is operated in three modes e.g. auto mode, semi-automatic mode
and manual mode. The programmable stop facility is only obtainable while the car
moves in automatic mode and controlled centrally only from HMI. In the semi-
auto mode the HMI can transfer control to any of the five LPBS as needed and the
car can be moved to any of the programmable stops or can be inched also, when
necessary. In the maintenance mode all the interlocks are bypassed and the cars
can only be inched. The E-stop facility is active in all the three modes of vehicle
operation.
e. Wireless transfer of control signals are communicated between a Master Antenna
on the Transfer car and a slave Antenna mounted in the pulpit, ensuring trouble
free communication between the Programmable Logic controller (PLC) in the
pulpit and the Devices on the transfer cars.
f. The Power and Control Supply to the equipment on Transfer Car comprising the
motor, Remote Input - Output (RIO) panel etc is through Shrouded Underground
Bus Bar System, each transfer car having 2 sets of Bus Bars, wherein one set
carries the power supply and the other set carries the Control Power Supply for
the brakes and other devices mounted on the Transfer car.
g. Encoder-Profibus connectivity: The position of the transfer car is shown in meters
from the datum position (ECL), by use of an encoder, visible in the HMI screen
and the position is updated continuously.
h. The PLC has a powerful S7-400 CPU for desired automation of the transfer cars and the drive speeds of the transfer car, both in inching mode or in Auto mode, can be set by the operator in the HMI to the desired value ranging between maximum values of 60mpm for Auto mode to the minimum 30mpm for inching. A Simovert Master Frequency Drive is used to achieve this functional control.


i. The Transfer car movement and control system for optimized operation in synchronization with the process line is having inbuilt safety features comprising,
LASER scanner to automatically detect object in front of the car while traveling and immediately stop the car.
Door limit switches are provided on the doors mounted on the fencing along the entire stretch of 230 meters track in the CRM bay, to facilitate safe crossing over the track at selective locations, avoiding accident due to fast moving transfer car. The car stops once the door is opened by the activation of the door limit switch and can be deactivated from the pulpit if required, and the access to such control is password protected.
Hooter and blinker provided on the Transfer car is provided to generate an audio visual alarm for people working in nearby area, which starts when the car starts and also stops functioning when the cars come to a halt.
- The transfer cars are provided with emergency stop (E-stop) facility provided by way of emergency push button on the car itself, on each of the LPBS, and also on the HMI in the pulpit. All of which are wired directly to the controller enabling instantaneous stoppage of the transfer cars during an emergency situation.
End stoppers and end limit switches, which ensure stoppage of the Transfer car well within the restricted area of operation and control, between ECL and SPM.
It is thus possible by way of this invention to develop Automated transfer cars for coil transportation/handling in the CRM complex in steel plants and a PLC based control system thereof for its speed and start/stop functions in said multi-process operational area covering a long bay from exit side of ECL to entry side of SPM, such as to provide safe, reliable, cost effective operation in sync with the optimized production processes involving minimum operators interference, and thus ensuring high amount of quality,


reliability and efficiency in overall operation as well as productivity in Cold Rolling Mill Complex in steel plants. The invention is further adapted to provide centralized control from the HMI at pulpit as well as combined distributed automation as an option from individual Local Push Button Station at selective strategic locations and a continuous monitoring and display of status of the location/movements or stop/start function on HMI screen as a operator friendly simple means of implementation of control of parameters for the complex processes comprising electrolytic cleaning of CR sheets through the BAF, CCSU and then to Skin Pass Mill (SPM) and forwarding thereafter the Skin Passed coils to recoiling and inspection and then final packing stage. The automated Transfer cars of the invention and the system of control thereof for synchronized performance matched with that of the automated production lines, are having advantageous industrial application in large steel industry.


WE CLAIM:
1. A system for automated coil transfer car for productivity improvement in cold rolling
mill complex comprising:
control means comprising a central control unit with human machine interface (HMI)
in the control pulpit and selectively disposed local control units at strategic locations
along its travel path, wherein the master control is with the HMI and the control
adapted to be transferred from said HMI to any LPBS as and when such instruction is
received from said HMI;
Means for wireless transfer of signal there between said transfer car and said central
control unit;
Shrouded underground bus bar power and control supply means adapted to operate
and control the equipments on the transfer car;
Means to selectively control the movement of the transfer car and also its strategic
stoppage at pre selected locations;
A PLC based transfer car speed control and setting provision; and
Means to selectively operate the transfer car in anyone of (a) automatic mode (b)
semi-automatic mode and (c) manual mode as may be desired.
2. A system for automated coil transfer car for productivity improvement in cold rolling
mill complex as claimed in claim 1 comprising safety features comprising selectively
anyone or more of the following:
Laser scanner adapted to stop the transfer car as and when any person or object is spotted in front of the car;


Fencing of the entire area of travel of the transfer car with door limit switches at
appropriate locations adapted such that car stops once a door is opened due to the
activation of said door limit switch;
Audio-visual alarm means adapted to indicate the starting and stopping of the car at
various locations;
Emergency stop facility; and
Mechanical end stoppers adapted to ensure stoppage of the car within safe and
restricted area.
3. A system for automated coil transfer car for productivity improvement in cold rolling mill complex as claimed in anyone of claims 1 or 2 wherein it is adapted for high capacity 150 tonnes, high speed 60 mpm, long transfer length 230 meters, high ambient operating temperature 50 deg C and transfer of coils of temperature as high as 120 deg C.
4. A system for automated coil transfer car for productivity improvement in cold rolling mill complex as claimed in anyone of claims 1 to 3 wherein the same comprises five local push button stations (LPBS) mounted at strategic locations.
5. A system for automated coil transfer car for productivity improvement in cold rolling mill complex as claimed in anyone of claims 1 to 4 wherein the communication is between a master antenna on the transfer car and a slave antenna mounted in the pulpit whereby a trouble free communication is established between the Programmable Logic Controller (PLC) in the pulpit and the devices in the Transfer Car.
6. A system for automated coil transfer car for productivity improvement in cold rolling mill complex as claimed in anyone of claims 1 to 5 wherein one set of bus bars carries


the power supply for the motors from the frequency drive and the other set carries the control power supply for the brakes and other devices on the transfer car.
7. A system for automated coil transfer car for productivity improvement in cold rolling mill complex as claimed in anyone of claims 2 to 6 wherein the door limit switches are adapted to be deactivated from the HMI in the Pulpit as and when required through secured password protected operation.
8. A system for automated coil transfer car for productivity improvement in cold rolling mill complex as claimed in anyone of claims 2 to 7 comprising emergency stop push buttons provided on the transfer car, on each of the LPBS and also on the HMI in the pulpit which are all hardwired directly to the Controller to enable immediate stoppage of the Transfer Car during an emergency.
9. A system for automated coil transfer car for productivity improvement in cold rolling mill complex as claimed in anyone of claims 1 to 8 comprising programmable stops adapted to stop at various strategic locations with high stoppage accuracy wherein preferably proximity switches are provided at such locations and the position is selected from the HMI or any of the LPBS if authorized and the car is thus adapted to move at specified locations and stops.
10. A system for automated coil transfer car for productivity improvement in cold rolling mill complex as claimed in anyone of claims 1 to 9 comprising encoder with Profibus connectivity whereby the position of the transfer car in meters from the datum position (ECL) is visible in the HMI and is updated continuously.

11. A system for automated coil transfer car for productivity improvement in cold rolling
mill complex as claimed in anyone of claims 1 to 10 comprising said PLC adapted to
control automation and drive of the car.
12. A system for automated coil transfer car for productivity improvement in cold rolling
mill complex substantially as herein described and illustrated with reference to the
accompanying figures.


ABSTRACT
TITLE: A SYSTEM FOR AUTOMATED COIL TRANSFER CAR FOR PRODUCTIVITY IMPROVEMENT IN COLD ROLLING MILL COMPLEX.
A system for automated coil transfer car for transporting Hot Rolled (HR) Coils from the Hot strip Mill (HSM) for processing in subsequent stages, and a control system thereof for operation in Cold Rolling Mill (CRM) complex. More particularly, the system for control of automated coil transfer cars matches with the degree of automation in CRM complex, aimed at achieving excellent quality and maximum productivity. The Master controller of the system is with Human machine Interface (HMI) at the pulpit having wireless central control and said control can be transferred from the HMI to any of the local push button stations (LPBS) on demand, such that either HMI or LPBS controls the speed or position of transfer cars at a time. The automated transfer cars are having 150 Tonne capacity, speed range of about 60mpm(max) to 30mpm(min), travel length of 230 meters, operating ambient temperature of 50°C and can carry coils at 120 °C, enabling maximizing productivity with minimum operator intervention, having wide industrial application and economy in production. Figure 4.