Title of Invention	A METHOD AND APPARATUS FOR COMPLETING AN UNFINISHED CYCLE OF A HYDRAULIC INJECTION MOULDING MACHINE DURING POWER SHUTDOWN
Abstract	The invention relates to a method and apparatus for completing an unfinished cycle of a hydraulic injection moulding machine during power shutdown. The invention includes devices for storing power in an electronic device and a hydraulic device. In the event of power failure, the power loss is detected by the signal provided by an electromechanical device. The electronic power storage device keeps the machine controller 'ON' and the hydraulic power storage device provides the motive power for completing the machine cycle. The controller, upon receiving the power loss signal, opens/closes necessary valves in a bypass arrangement and ensures that the cycle reaches its logical end by drawing power from the hydraulic power storage device for the movement of the actuators. Upon completing the cycle, the hydraulic power storage is depressed and the electronic power storage device shuts off the power to the controller. FIGURE 2.

Title of Invention

A METHOD AND APPARATUS FOR COMPLETING AN UNFINISHED CYCLE OF A HYDRAULIC INJECTION MOULDING MACHINE DURING POWER SHUTDOWN

Abstract

The invention relates to a method and apparatus for completing an unfinished cycle of a hydraulic injection moulding machine during power shutdown. The invention includes devices for storing power in an electronic device and a hydraulic device. In the event of power failure, the power loss is detected by the signal provided by an electromechanical device. The electronic power storage device keeps the machine controller 'ON' and the hydraulic power storage device provides the motive power for completing the machine cycle. The controller, upon receiving the power loss signal, opens/closes necessary valves in a bypass arrangement and ensures that the cycle reaches its logical end by drawing power from the hydraulic power storage device for the movement of the actuators. Upon completing the cycle, the hydraulic power storage is depressed and the electronic power storage device shuts off the power to the controller. FIGURE 2.

Full Text	The present invention provides a method and apparatus for completing an unfinished cycle of a hydraulic injection moulding machine during power shutdown. The invention provides an simple and economical solution for completing the working cycle of the hydraulic powered injection moulding machine and ejecting the plastic component from the mould, thus saving time and the form of the half-moulded component. BACKGROUND OF THE INVENTION Hydraulic injection moulding machines generally consist of one or more pumps driven by one or more electric motors. The pumps circulate oil to the various actuators of the machine through a network of electrically driven valves and piping. The operating voltage signals for these valves are released by a central controller, which continuously monitors the machine sequence, physical conditions and time and determines the output signals to be released in accordance with a program or logic residing in the controller. The machine operates cyclically and the mode of operation during production can be automatic (the next cycle can start without operator intervention) or semi-automatic (the next cycle can start only with operator intervention). An unscheduled power loss at any point during the cycle brings the machine to a halt. The unscheduled stoppage of the machine in the middle of a production cycle can cause several problems apart from the obvious problem of production loss. This present invention addresses specifically the difficulty in ejecting the plastic components after their prolonged stay inside the mould during the power outage leading to time lost in removing the uncompleted solidified moulding remaining in the mould (sometimes causing damage to the mould as well) even after the resumption of the power supply. The difficulty arises because of either the geometry or the material characteristic of the plastic component. This invention provides a way for completing the cycle and ejecting the plastic components from the mould (even though these components may be rejected), so that the machine and mould are both ready to start production again once the power supply resumes. The conventional way to complete the machine cycle without interruption is by running the machine on an Uninterrupted Power Supply (UPS) system, which involves expensive investment in storage batteries and electronics. Further the floor space and the maintenance requirements of such schemes are generally high. Another scheme involves the use of alternative power supply (such as a diesel generator set), which can be started in the event of power failure. But in such cases, the loss of cycle continuity (specifically the time required to detect and start the generator) also could lead to the plastic melt not being fully injected into the mould and thus discontinuity in cycle and consequent loss of time in resuming the machine operation once the power resumes. Alternatively, the machine could be put to use continuously powered by a gen-set, thus countering the effect of a power outage. But this is a rather expensive solution. This invention achieves the objective of minimal time loss and loss of production by an inexpensive method and apparatus. This allows the machine to operate on local power supply or genset, as the case may be without time loss and possible damage to the mould. SUMMARY OF THE INVENTION The object of the invention is to provide a method and apparatus for completing an unfinished cycle of a hydraulic injection moulding machine during power shutdown. The electric power for keeping the controller of the hydraulic injection moulding machine ON during power outage comes from an electronic power storage device which is a UPS sized to meet only the control power requirement. The power for moving the actuators during shutdown comes from a hydraulic power storage device, which can be attached to the machine permanently. The controller, upon receiving the power loss signal, opens/closes necessary valves in a by-pass arrangement and ensures that the cycle reaches its logical end by drawing power from the hydraulic power storage device for the movement of the actuators. Upon completing the cycle, the hydraulic power storage is depressurized and the electronic power storage device shuts off the power to the controller. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a schematic diagram of the steps involved in the method of completing an unfinished cycle of the hydraulic injection moulding machine according to the present invention. Figure 2 shows a block diagram of the injection moulding system along with the electronic power storage device (3) and the hydraulic power storage device (4) according to the present invention. DETAILED DESCRIPTION OF THE DISCLOSURE The present invention provides a method and apparatus for completing an unfinished cycle of a hydraulic injection moulding machine during power shutdown. The method of the present invention is safe economical and time saving, without using elaborate power supply machines and devices. The apparatus required to work the invention does not occupy much space and is very easy and compact to use and maintain. The working mechanism of the method and apparatus for completing a logical working cycle of a hydraulic power shutdown is as follows. The injection moulding machine (1) has functions such as closing the mould, locking the mould, injecting the plastic melt, cooling the mould to allow plastic to solidify and take the shape of the inner contours of the mould, preparing plastic melt for the next 'shot', opening the mould upon completion of the cooling cycle and ejecting out the solidified component in sequence. When there is a power shutdown, the piece to be moulded is usually still in the mould, halfway done. When power resumes, it is indeed quite a time consuming task to remove this piece from the mould, to resume the next cycle. Therefore in order to ease cycle completion during power shutdown, an arrangement is made such that power is stored in an electronic device (3) as well as in a hydraulic device (4). The electronic device may be an uninterrupted power supply (UPS) and the hydraulic device may be a bladder accumulator (4). During normal working of the machine, when main power supply is present, the hydraulic injection moulding machine draws power from the mains. The main power supply powers the motor (la) of the machine (1). The power that goes to the control circuit or controller (2) of the machine (1) is through a UPS(3). When the main power supply is ON, the accumulator (4) is charged to the required level. During normal conditions, the valves and actuators of the machine (1) receive their working power from the pumps which are attached to the motor (la). These pumps will rotate as long as the main power supply is present. When main power shutdown occurs, the pumps attached to the motor (la) stop rotating and thus the actuators of the machine (1) do not receive power. However, the controller (2) still receives its power from the UPS (3). This UPS (3) is sized to meet only control power requirement and is designed only for supplying power to the controller (2) of the machine (1). The controller (2), powered by the UPS (3) senses this break in main power supply and controls the operation of the different valves in the injection cylinder (lb), clamping cylinder (lc) and ejector cylinder (Id) of the machine (1), in such a way that the movement of actuator is powered by the accumulator (4) and not by the pumps of the motor (la). This accumulator (4) is a hydraulic power storage device that is sized and designed to provide sufficient energy and power for completing only the cycle that was going on and was unfinished when the main power supply had stopped. This accumulator is usually a bladder accumulator. This consists of two fluids separated by a rubber bladder one being the incompressible hydraulic oil and the other being a compressible inert gas like nitrogen. The compressible gas is already under a pre-filled pressure and kept enclosed in the rubber bladder. When oil is pumped at a high pressure into this chamber, the pressure of the oil gets transferred to the gas (much like the winding up of a clock spring) which then compresses further thus storing the energy contained in the oil and making way for the incoming oil without physical contact with each other because of the bladder wall. When oil is allowed out of the accumulator, the pressure in the gas reduces by expanding, forcing the oil out of the accumulator, thus giving hydraulic oil flow at pressure, much like the clock spring driving the clock. Other type of accumulators [(e.g.) a ram type accumulator] may also be used as the hydraulic storage device in this invention. Upon completion the cycle, the accumulator is depressurized and the UPS (3) shuts off its power supply to the controller (2). Thus, the unfinished cycle of the injection moulding machine (1) completes successfully and the finished components are ejected from the mould, without causing any time loss or damage to the mould. When main power resumes again, the machine (1) is ready to start production. In case the main power resumes before the machine (1) fully shuts downs, the machine (1) issues a warning that the power has resumed but the pumps are off. The normal operation is then stalled until, the unfinished cycle gets completed and the component is ejected. We claim: 1. A method for completing an unfinished cycle of a hydraulic injection moulding machine during power shut down, comprising the steps of routing power supply to a controller of said hydraulic injection moulding machine through a separate electronic power storage device; charging an hydraulic power storage device to a level sufficient for supplying power for the completion of a single cycle of the hydraulic injection moulding machine characterized in that during power shut down it comprises the steps of, operating the valves of the hydraulic injection moulding machine by the controller, using the power supplied by the electronic power storage device, operating the actuators of the hydraulic injection moulding machine with the power derived from the hydraulic power storage device, said hydraulic power being controlled by the operation of the valves which are driven by the controller, deriving sufficient power from the hydraulic power storage device for the actuator to complete a single unfinished cycle of the hydraulic injection moulding machine, depressurizing the hydraulic power storage device and shutting down the electro storage device on cycle completion of the hydraulic injection moulding machine and ejecting a finished component from the mould of the hydraulic injection moulding machine. 2. The method as claimed in claim 1 wherein the electronic power storage device is designed to supply power only to the controller of the hydraulic injection moulding machine. 3. The method as claimed in claim 1 wherein said controller triggers the opening and closing of the valves of the hydraulic injection moulding machine in a bypass arrangement so that the actuators receive sufficient power from the hydraulic power storage device to complete one cycle. 4. An apparatus for completing an unfinished cycle of a hydraulic moulding machine during power shut down comprising: an electronic power storage device (3) for supplying power to the controller (2) of the hydraulic injection moulding machine (1); and a hydraulic power storage device (4) for supplying sufficient power to the actuators of said hydraulic injection moulding machine to complete one logical unfinished cycle during power shutdown. 5. The apparatus as claimed in claim 4 wherein the electronic power storage device (3) is an uninterrupted power supply (UPS). 6. The apparatus as claimed in claim 4 wherein the hydraulic power storage device (4) is an accumulator. 7. The apparatus as claimed in claim 6 wherein said accumulator is a bladder accumulator. 8. The apparatus as claimed in claim 6 wherein said accumulator is a piston accumulator. Dated this 5th day of January 2006.

Full Text

The present invention provides a method and apparatus for completing an unfinished cycle of a hydraulic injection moulding machine during power shutdown. The invention provides an simple and economical solution for completing the working cycle of the hydraulic powered injection moulding machine and ejecting the plastic component from the mould, thus saving time and the form of the half-moulded component.
BACKGROUND OF THE INVENTION
Hydraulic injection moulding machines generally consist of one or more pumps driven by one or more electric motors. The pumps circulate oil to the various actuators of the machine through a network of electrically driven valves and piping. The operating voltage signals for these valves are released by a central controller, which continuously monitors the machine sequence, physical conditions and time and determines the output signals to be released in accordance with a program or logic residing in the controller.
The machine operates cyclically and the mode of operation during production can be automatic (the next cycle can start without operator intervention) or semi-automatic (the next cycle can start only with operator intervention). An unscheduled power loss at any point during the cycle brings the machine to a halt. The unscheduled stoppage of the machine in the middle of a production cycle can cause several problems apart from the obvious problem of production loss.
This present invention addresses specifically the difficulty in ejecting the plastic components after their prolonged stay inside the mould during the power outage leading to time lost in removing the uncompleted solidified moulding remaining in the mould (sometimes causing damage to the mould as well) even after the resumption of the power supply. The difficulty arises because of either the geometry or the material characteristic of the plastic component. This invention provides a way for completing the cycle and ejecting the plastic components from the mould (even though these components may be rejected), so that the machine and mould are both ready to start production again once the power supply resumes.

The conventional way to complete the machine cycle without interruption is by running the machine on an Uninterrupted Power Supply (UPS) system, which involves expensive investment in storage batteries and electronics. Further the floor space and the maintenance requirements of such schemes are generally high.
Another scheme involves the use of alternative power supply (such as a diesel generator set), which can be started in the event of power failure. But in such cases, the loss of cycle continuity (specifically the time required to detect and start the generator) also could lead to the plastic melt not being fully injected into the mould and thus discontinuity in cycle and consequent loss of time in resuming the machine operation once the power resumes.
Alternatively, the machine could be put to use continuously powered by a gen-set, thus countering the effect of a power outage. But this is a rather expensive solution. This invention achieves the objective of minimal time loss and loss of production by an inexpensive method and apparatus. This allows the machine to operate on local power supply or genset, as the case may be without time loss and possible damage to the mould.
SUMMARY OF THE INVENTION
The object of the invention is to provide a method and apparatus for completing an unfinished cycle of a hydraulic injection moulding machine during power shutdown. The electric power for keeping the controller of the hydraulic injection moulding machine ON during power outage comes from an electronic power storage device which is a UPS sized to meet only the control power requirement. The power for moving the actuators during shutdown comes from a hydraulic power storage device, which can be attached to the machine permanently.
The controller, upon receiving the power loss signal, opens/closes necessary valves in a by-pass arrangement and ensures that the cycle reaches its logical end by drawing power from the hydraulic power storage device for the movement of the actuators. Upon completing

the cycle, the hydraulic power storage is depressurized and the electronic power storage device shuts off the power to the controller.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a schematic diagram of the steps involved in the method of completing an unfinished cycle of the hydraulic injection moulding machine according to the present invention.
Figure 2 shows a block diagram of the injection moulding system along with the electronic power storage device (3) and the hydraulic power storage device (4) according to the present invention.
DETAILED DESCRIPTION OF THE DISCLOSURE
The present invention provides a method and apparatus for completing an unfinished cycle of a hydraulic injection moulding machine during power shutdown. The method of the present invention is safe economical and time saving, without using elaborate power supply machines and devices. The apparatus required to work the invention does not occupy much space and is very easy and compact to use and maintain.
The working mechanism of the method and apparatus for completing a logical working cycle of a hydraulic power shutdown is as follows.
The injection moulding machine (1) has functions such as closing the mould, locking the mould, injecting the plastic melt, cooling the mould to allow plastic to solidify and take the shape of the inner contours of the mould, preparing plastic melt for the next 'shot', opening the mould upon completion of the cooling cycle and ejecting out the solidified component in sequence. When there is a power shutdown, the piece to be moulded is usually still in the mould, halfway done. When power resumes, it is indeed quite a time consuming task to remove this piece from the mould, to resume the next cycle. Therefore in order to ease cycle completion during power shutdown, an arrangement is made such that power is stored in an electronic device (3) as well as in a hydraulic device (4). The electronic device

may be an uninterrupted power supply (UPS) and the hydraulic device may be a bladder accumulator (4).
During normal working of the machine, when main power supply is present, the hydraulic injection moulding machine draws power from the mains. The main power supply powers the motor (la) of the machine (1). The power that goes to the control circuit or controller (2) of the machine (1) is through a UPS(3). When the main power supply is ON, the accumulator (4) is charged to the required level. During normal conditions, the valves and actuators of the machine (1) receive their working power from the pumps which are attached to the motor (la). These pumps will rotate as long as the main power supply is present. When main power shutdown occurs, the pumps attached to the motor (la) stop rotating and thus the actuators of the machine (1) do not receive power. However, the controller (2) still receives its power from the UPS (3). This UPS (3) is sized to meet only control power requirement and is designed only for supplying power to the controller (2) of the machine (1).
The controller (2), powered by the UPS (3) senses this break in main power supply and controls the operation of the different valves in the injection cylinder (lb), clamping cylinder (lc) and ejector cylinder (Id) of the machine (1), in such a way that the movement of actuator is powered by the accumulator (4) and not by the pumps of the motor (la). This accumulator (4) is a hydraulic power storage device that is sized and designed to provide sufficient energy and power for completing only the cycle that was going on and was unfinished when the main power supply had stopped. This accumulator is usually a bladder accumulator. This consists of two fluids separated by a rubber bladder one being the incompressible hydraulic oil and the other being a compressible inert gas like nitrogen. The compressible gas is already under a pre-filled pressure and kept enclosed in the rubber bladder. When oil is pumped at a high pressure into this chamber, the pressure of the oil gets transferred to the gas (much like the winding up of a clock spring) which then compresses further thus storing the energy contained in the oil and making way for the incoming oil without physical contact with each other because of the bladder wall. When oil is allowed out of the accumulator, the pressure in the gas reduces by expanding, forcing the oil out of

the accumulator, thus giving hydraulic oil flow at pressure, much like the clock spring driving the clock.
Other type of accumulators [(e.g.) a ram type accumulator] may also be used as the hydraulic storage device in this invention. Upon completion the cycle, the accumulator is depressurized and the UPS (3) shuts off its power supply to the controller (2). Thus, the unfinished cycle of the injection moulding machine (1) completes successfully and the finished components are ejected from the mould, without causing any time loss or damage to the mould. When main power resumes again, the machine (1) is ready to start production.
In case the main power resumes before the machine (1) fully shuts downs, the machine (1) issues a warning that the power has resumed but the pumps are off. The normal operation is then stalled until, the unfinished cycle gets completed and the component is ejected.

We claim:
1. A method for completing an unfinished cycle of a hydraulic injection moulding
machine during power shut down, comprising the steps of
routing power supply to a controller of said hydraulic injection moulding machine through a separate electronic power storage device;
charging an hydraulic power storage device to a level sufficient for supplying power for the completion of a single cycle of the hydraulic injection moulding machine
characterized in that during power shut down it comprises the steps of, operating the valves of the hydraulic injection moulding machine by the controller, using the power supplied by the electronic power storage device, operating the actuators of the hydraulic injection moulding machine with the power derived from the hydraulic power storage device, said hydraulic power being controlled by the operation of the valves which are driven by the controller, deriving sufficient power from the hydraulic power storage device for the actuator to complete a single unfinished cycle of the hydraulic injection moulding machine,
depressurizing the hydraulic power storage device and shutting down the electro storage device on cycle completion of the hydraulic injection moulding machine and
ejecting a finished component from the mould of the hydraulic injection moulding machine.
2. The method as claimed in claim 1 wherein the electronic power storage device is designed to supply power only to the controller of the hydraulic injection moulding machine.
3. The method as claimed in claim 1 wherein said controller triggers the opening and closing of the valves of the hydraulic injection moulding machine in a bypass arrangement so that the actuators receive sufficient power from the hydraulic power storage device to complete one cycle.

4. An apparatus for completing an unfinished cycle of a hydraulic moulding machine
during power shut down comprising:
an electronic power storage device (3) for supplying power to the controller (2) of the hydraulic injection moulding machine (1); and
a hydraulic power storage device (4) for supplying sufficient power to the actuators of said hydraulic injection moulding machine to complete one logical unfinished cycle during power shutdown.
5. The apparatus as claimed in claim 4 wherein the electronic power storage device (3) is an uninterrupted power supply (UPS).
6. The apparatus as claimed in claim 4 wherein the hydraulic power storage device (4) is an accumulator.
7. The apparatus as claimed in claim 6 wherein said accumulator is a bladder accumulator.
8. The apparatus as claimed in claim 6 wherein said accumulator is a piston accumulator.
Dated this 5th day of January 2006.

Documents:

0027-che-2006-abstract.pdf

0027-che-2006-claims.pdf

0027-che-2006-correspondnece-others.pdf

0027-che-2006-description(complete).pdf

0027-che-2006-drawings.pdf

0027-che-2006-form 1.pdf

0027-che-2006-form 26.pdf

0027-che-2006-form 3.pdf

27-CHE-2006 AMENDED PAGES OF SPECIFICATION 02-01-2012.pdf

27-CHE-2006 CORRESPONDENCE OTHERS 28-08-2012.pdf

27-CHE-2006 CORRESPONDENCE OTHERS 02-01-2012.pdf

27-che-2006 form-18 15-11-2007.pdf

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Patent Number

254146

Indian Patent Application Number

27/CHE/2006

PG Journal Number

39/2012

Publication Date

28-Sep-2012

Grant Date

24-Sep-2012

Date of Filing

05-Jan-2006

Name of Patentee

L&T-DEMAG PLASTICS MACHINERY PVT LIMITED

Applicant Address

POST BAG NO. 986, MOUNT POONAMALLEE ROAD, MANAPPAKKAM, CHENNAI 600089.

Inventors:

#	Inventor's Name	Inventor's Address
1	KUMAR MATHRUBOOTHAM	C/O L&T-DEMAG PLASTICS MACHINERY LIMITED, PB NO. 5 CHEMBARAMBAKKAM, OFF CHENNAI BANGALORE HIGHWAY, CHENNAI 602103.
2	SAJU MANGALASSERI	C/O L&T-DEMAG PLASTICS MACHINERY LIMITED, PB NO. 5 CHEMBARAMBAKKAM, OFF CHENNAI BANGALORE HIGHWAY, CHENNAI 602103.
3	SIVAKUMAR SHANMUHAM	C/O L&T-DEMAG PLASTICS MACHINERY LIMITED, PB NO. 5 CHEMBARAMBAKKAM, OFF CHENNAI BANGALORE HIGHWAY, CHENNAI 602103.
4	LANKA SADANAND	C/O L&T-DEMAG PLASTICS MACHINERY LIMITED, PB NO. 5 CHEMBARAMBAKKAM, OFF CHENNAI BANGALORE HIGHWAY, CHENNAI 602103.
5	VAIDYANATHAN KRISHNAMOORTHY	C/O L&T-DEMAG PLASTICS MACHINERY LIMITED, PB NO. 5 CHEMBARAMBAKKAM, OFF CHENNAI BANGALORE HIGHWAY, CHENNAI 602103.
6	SESHADRI NAGARAJAN SUNDARARAMAN	C/O L&T-DEMAG PLASTICS MACHINERY LIMITED, PB NO. 5 CHEMBARAMBAKKAM, OFF CHENNAI BANGALORE HIGHWAY, CHENNAI 602103.
7	PRASHANTHA KINI	C/O L&T-DEMAG PLASTICS MACHINERY LIMITED, PB NO. 5 CHEMBARAMBAKKAM, OFF CHENNAI BANGALORE HIGHWAY, CHENNAI 602103.

PCT International Classification Number

B29C45/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA