F O R M 2

THE PATENTS ACT, 1970

(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION

(See section 10; rule 13)

1. Title of the invention - AN IMPROVED REMOTELY CONTROLLED WIRELESS
ELECTROMAGNETIC ACTUATION SYSTEM

2. Applicant(s)

(a) NAME: LARSEN & TOUBRO LIMITED

(b) NATIONALITY : An Indian Company

(c) ADDRESS : L & T House, Ballard Estate, Mumbai 400 001, State of
Maharashtra, India

3. PREAMBLE TO THE DESCRIPTION

The following specification particularly describes the invention and the manner in which it is to be performed:

Field of the invention

The present invention relates to a remotely controlled wireless electromagnetic actuation. More particularly, the invention is concerned about developing an improved wireless system for electromagnetic actuation for use in switching any kind of appliances covering from domestic to distribution circuit and power gear devices. The switching is done without the usage of cables running from the input circuit to output device.

Background and the prior art

Actuation technology can be broadly classified under direct or indirect effects those are responsible to cause a physical function. Most of the technology with indirect effect is with 2 to 3 stage of physical functions, which cause an actuation. All these technologies involve physical wiring for transfer of input signal to the output device. It has been found that one of factors which determines delay dropout in electromagnetic device is due to cable capacitance. The long distance cable between the input & output circuit develops cable capacitance, which is responsible for delay in drop out of the electromagnetic device. For a typical cable connected as two wires & three wire control system, would generate a cable capacitance of 0.3F/km and 0.6F/km respectively. This will restrict the cable length to 320m & 180m for a two wire & 3wire system suitable for controlling 10VA electromagnetic system. This problem thus calls for a technology, which will eliminate the root cause that is control cable wiring between the input & output circuit.

US2006/0033597 A1 discloses a wireless alarm, which incorporates a battery powered transmitter and receiver circuit to cause an alarm through an audible alarm. The detector circuit generates an output (voltage) pulse to drive the alarm electromagnet. However, there was no teaching in the prior art about a wireless actuation, which could produce modulated high time pulse for both the ON & OFF switching operation by means of changing the state of the output from high to low in two simultaneous consecutive operations.

US2007/0157257A1 discloses a wireless communication systems and method, which uses the radio frequency electromagnetic wave for accessing information using wireless communication. In the prior art wireless actuation with controlled response time and force stroke characteristics was not found. It was also not known that switching On & Off operation can be done from a single dip switch in a wireless communication system.

US2007/0254708A1 discloses a handheld wireless communication device, which send signal to a display unit similar to a mobile.

US2008/0060707A1 discloses a Remote shower actuation and temperature sensing unit, which is installed in a shower having a shower head in a water line that is downstream of hot and cold water mixing for the shower. The shower actuator includes a battery powered wireless actuating blocked valve and digital temperature sensor mechanism, temperature indicating mechanism along with two independent wireless controllers for the desired wireless actuation. IRF wireless actuation device, which is meant for switching electromagnetic actuators such as solenoid, contactor, electrical operator and relay etc. was not found in the prior art document.

US2009/0103307 discloses a wireless control lamp structure, which comprise of a temperature and wireless control module, which receives wireless control signal to control the actuation of the lamp However, IRF based remotely controlled actuation which is meant for switching electromagnetic actuators such as solenoid, contactor, electrical operator and relay etc. was not found in the prior art document.

US2009/0222141A1 discloses an irrigation control system, which includes a transmitter unit including a controller and having a connector to be coupled to an irrigation controller having station actuation output connectors. The receiving unit is coupled to an actuator coupled to an actuating device such as an irrigation valve to control the flow of water. IRF wireless actuation device, which is meant for switching electromagnetic actuators such as solenoid, contactor, electrical operator and relay etc. was not found in the prior art document.

US2009 / 0315672 A1 discloses about a programmable wireless remote control systems, which will only produce a positive signal output for changing the state of the device from high to low and vice-versa. The system of this prior art will not be able to operate devices such as electrical operator or magnetically latched device, which need a reverse supply for switching OFF operation.

US2010 / 0045456 A1 discloses a wireless item locator doorbell system, which comprises of a doorbell unit followed by a motion sensor, actuating mechanism, transmitter wireless signal generation unit and receiver unit. Upon receiving a signal, the motion sensor creates an output to drive the actuating mechanism which generates wireless signal, which is received by the receiver circuit to develop an analog output.

WO2009/003303A3 teaches concerns a novel magnetic actuator mechanism suitable for use on untethered microrobots. It relies on the interaction of magnetic bodies in an external magnetic field. By an oscillating field, the bodies are driven to oscillatory motion and the energy stored in the oscillation is harnessed.

WO2010/081816A1 discloses a monitoring system for monitoring a state of a door lock mechanism of a door or of a closure of a storage space of a means of transportation comprising a generator, sensor and actuator. The generator produces electrical energy from vibration energy and the sensor detects the state of the door lock mechanism. The sensor uses kinetic energy that is produced by the actuation of the door lock to generate an electrical signal, which is then transmitted to a micro- controller.

 All the cited technology reveals towards a wireless system, which is able to operate most of the consumer appliances. However the systems as described in these prior art will not be able to operate devices such as electrical operator or magnetically latched device, which need a reverse supply for switching OFF operation. The present invention focus towards a novel wireless electromagnetic actuation, which will eliminate control cables running over long distance in the secondary distribution, building and automation sector. It has been found by the present inventors that usage of infrared LED in a unique circuit configuration, which will develop reverse control supply for switching OFF operation for providing an improved wireless system for electromagnetic actuation for use in switching any kind of appliances covering from domestic to distribution circuit and power gear devices. It has further been found by the inventors that the operating distance for wireless communication for use in switching any kind of appliances covering from domestic to distribution circuit and power gear devices can be increased to a much higher level by means of radio frequency electromagnetic waves for detection of the input signal. This will avoid the line of sight problem due to intermediate obstacles appearing between the transmitter and detector circuit. However care shall be taken at the receiving end to shield against external electromagnetic wave intervening the detector module. Also radio frequency wave is affected by material like steel, wall, window glass etc.

Most of the wireless actuation circuit or controller presently disclosed is towards switching electromagnetic devices such as solenoid, control relays and other domestic appliances viz. air-conditioner, TV, car door locking system, shutters, white boards etc, where the control supply to the coil is fed through two different input circuits. However these circuits are not suitable for switching devices like magnetically latched contactor, electrical operator etc. as they will not develop reverse control supply for switching OFF operation.

Objects of the invention

A basic object of the present invention is to overcome the drawbacks of the prior art and to overcome the problems associated with delay in dropout of electromagnetic devices due to cable capacitance in the output circuit.

One object of the present invention is to provide an improved wireless system for electromagnetic actuation for use in switching any kind of appliances covering from domestic to distribution circuit and power gear devices.

Another object of the present invention is to provide infrared wireless system for electromagnetic actuation.

Another object of the present invention is to increase the operating distance for wireless communication by using radio frequency communication.

A further object of the present invention is to provide developing of reverse control supply for switching OFF operation.

Summary of the invention

According to an aspect of the present invention there is provided an improved wireless system for electromagnetic actuation comprising :
transmitter unit;
detector unit;
wherein said transmitter unit comprising
enclosure means;
transmitter circuit comprising electronic module;
means for generating infrared electromagnetic waves;
means for transporting said infrared electromagnetic waves to said detector unit;
wherein said detector unit comprising
a triggering means so as to develop an inverted output signal providing a high ON time astable pulses;
means for latching and de-latching the said output signal; and
means for operating a conventional auxiliary electromagnetic device which further operates a conventional high power electromagnetic device.

Detailed description of the invention

In order to attain the above-mentioned objects the present invention focus towards a novel wireless electromagnetic actuation, which will eliminate control cables running over long distance in the secondary distribution, building and automation sector. The system of the present invention comprises infrared LED in a unique circuit configuration in transmitting and the receiving/detecting end, which develops reverse control supply for switching OFF operation for providing an improved wireless system for electromagnetic actuation for use in switching any kind of appliances covering from domestic to distribution circuit and power gear devices.

The operating distance for wireless communication for use in switching any kind of appliances covering from domestic to distribution circuit and power gear devices can be increased to a much higher level by means of radio frequency electromagnetic waves for detection of the input signal.

During first operation, the input signal generated will develop a positive continuous voltage, which remains at high state to supply power continuously to the coil of the device such as home appliances, building and automation devices, control relay or contactor. In the next operation, it will cause change in the state of output signal to low. This will cut off the supply to the coil, to cause a switching OFF operation of the device. Apart from this in order to switch special devices such as magnetically latched contactor, circuit breaker, RCCB and electrical operator, the invention discloses a modified version of wireless actuation circuit, which develops a positive voltage pulse for a brief duration of 1 sec to switch on the device so that the coil does not consume power continuously. However the On time duration can be suitably reduced depending upon the closing time of the electromagnetic device. In the next operation, the detector circuit will develop a reverse pulse for a brief duration to switch OFF the device.

The invention is explained in greater details with reference to the exemplary drawings and the detailed description of the constructional features of the system. Further functioning of the system has been discussed below to describe the way the system operates. However, such description should not be considered as any limitation of scope of the present system. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.

Brief description of the accompanying drawings

Referring to the exemplary drawings wherein like elements is numbered alike in the accompanying Figures:

Figure 1 illustrates an isometric view of transmitter unit of the system of the present invention.
Figure 2 illustrates a circuit diagram of the transmitter unit of the system of the present invention.
Figure 3 illustrates an isometric view of the transmitter PCB unit with self back supply.
Figure 4 illustrates an isometric view of detector unit.
Figure 5 illustrates a PCB unit of the detector circuit.
Figure 6 illustrates a detector circuit for a conventional electro-magnetic device.
Figure 7 illustrates detector circuit for a magnetically latched electromagnetic device.
Figure 8 shows an output waveform of low frequency carrier circuit.
Figure 9 shows an output waveform of high frequency carrier circuit.
Figure 10 shows an oscillatory output pulse fed to infrared frequency LED.

Figure 11 shows Schmitt trigger circuit waveform showing definition of Vp, where VN and VH are between 30% and 70% limit.
Figure 12 shows waveform of the inverting effect of the Schmitt trigger circuit.
Figure 13 shows a demodulated output pulse of the Darlington circuit which is fed to Relay K1.
Figure 14 illustrates test setup for performance evaluation of wireless actuation.
Figure 15 shows performance evaluation of wireless actuation with an electromagnetic device (bread board level).
Figure 16 shows performance evaluation of wireless actuation with an electromagnetic device (with PCB unit).

Detailed description of the invention with reference to the accompanying drawings

Construction of the device

The device consists of a transmitter unit, which can be operated through a dip switch and detector unit, which is add on part of the electromagnetic switching device. The transmitter unit (Ttrans) comprising of an insulated enclosure/housing (ET), a lens (LT) to pass the infrared light emitted from the transmitter circuit, electronic module and cover to enclose and protect the electronic unit against pollution and ingress material. The electronic module of the transmitter unit comprises of battery operated DC source (DT shown in figure 2), dip switch (S1 shown in figure 2), three IC’s (IC1, IC2 and IC3) to generate a modulated higher frequency burst of pulses to drive the IRF LED (LIRF shown in figure 2). The electromagnetic wave that is generated from the IRF range from 780nm to 790nm with a carrier frequency of 38 KHz to 40KHz. Figure 1 & 2 shows the isometric view & circuit diagram of transmitter unit. As shown in figure – 3, the transmitter circuit is provided with a dip switch which when operated, causes generation of infra red rays at a desired frequency & wavelength. This is received by the detector unit (D) comprising of detecting unit (TSOP1738), inverted Schmitt trigger IC to develop a inverted output of the TSOP1738, IC555 to develop a high ON time astable pulses, JK flip flop for latch & de-latch the signal, Darlington amplifier unit (IC ULN2803) and relay driver circuit for operation of an auxiliary electromagnetic device, which further operates the high power electromagnetic device. Figure – 4, 5 and 6 shows the isometric view, PCB unit & circuit diagram of the detector unit, which is self explanatory. As revealed in the overview of invention, the modified circuit in the detection circuit will aid in operating a magnetically latched & manually operated switching device. Figure – 7 shows the circuit diagram of the same, which is self explanatory.

Functioning of the device

The transmitter circuit can be driven by an alkaline or lithium battery with a suitable Ampere-hour. When the dip switch is made “ON”, the battery supply is fed to the three IC’s, whose pin 8 is connected in common to the input voltage supply. Upon receiving the supply, IC555A oscillates at a lower frequency of < 50Hz.Refer figure – 8, which shows the low frequency pulse developed by IC555A (IC1). Output pin 3 of IC555A, is fed to pin 4 of IC555B (IC2). When the Pin 3 of IC 555A changes its state then IC555B gets triggered to cause an oscillation of few Hz (<150 Hz) and is the carrier wave for the IRF circuit. Refer figure – 9, which shows the carrier wave. Output pin 3 of IC555B, is fed to pin 4 of IC555C (IC3). In each cycle when the output pin 3 of IC555A changes its state, triggers IC555C to generate burst of modulated pulses, which oscillates at a very high frequency of few KHz(<30KHz). Refer figure – 10, which shows the modulated burst of pulses. These pulses are fed to the IR LED via a current limiting resistor so as to prevent damage to the LED. Upon receiving the modulated pulses, the LED elements such as GaAlAs or GaAs, gets heated up due to Joules heating.
Heating of these elements develops infrared electromagnetic waves, which is produced in the form of packet at a wavelength of 940nm with a light intensity spreading over an angular displacement of 17º. With the increase in the distance, the light intensity of the LED falls down to almost 70% of its total intensity at an angular displacement of 80º. The maximum forward current of the LED is 100mA at a voltage of 1.3 to 1.6V, with a radiant intensity of 200mW/sr and radiant power of 35mW. It has a very low response time of few ns (800ns). The highly modulated electromagnetic wave when falls upon the elements of the detector unit (TSOP1738), due to photovoltaic effect produces an output voltage. The detector unit is a photo detector as well as an amplifier and a demodulator so as to create a high ON time constant output pulse. The output of the photo module is fed to an inverting Schmitt trigger circuit, which rejects the noise generated by it and inverts the waveform. This means if the output of photo detector is high with noise, the Schmitt trigger output will be at low state.

Figure – 11 shows the smoothening of the output pulse due to hysteresis effect of the inverting Schmitt trigger circuit. Another advantage of using this circuit is to provide an “ON” delay in generating the first pulse to the electromagnetic device. This avoids any malfunctioning of the detector circuit.

Figure – 12 shows the inverting effect of the Schmitt trigger circuit. In order to avoid nuisance operation of the electromagnetic device, it is necessary to latch the output pulse for short duration so as to provide the desired closing time. The IC555 monostable timer connected at the output of Schmitt trigger circuit, develops a pulse for a long duration (<1second). Hence it is recommended to hold the dip switch pressed for less than 1 second. In case it is needed for holding the switch pressed for longer duration the ON time pulse of the monostable needs to be increased. This can be achieved by means of varying its discharge resistor & capacitor value. By doing so, mal-operation of the device can be prevented. This pulse is then fed to the clock of JK flip-flop so as to latch the state of the output per operation. This means the electrical output of the Flip-Flop will remain at high state when the dip switch is pressed once. In the subsequent next operation, it will go to low state. The output current of the Flip – Flop circuit is very low and is not sufficient to drive the electromagnetic relay. Hence a pre-amplification of the current is needed to drive the relay circuit. This is obtained by means of incorporating a high voltage & power Darlington circuit such as ULN2803. This circuit includes series connection of two transistors with high current transfer ratio. The resultant current transfer ratio, which is multiplication of the individual ones, is very high of the order 1000 times. Also due to its hysteresis effect, the output of the Darlington circuit is slightly delayed by a factor of 0.1s as compared to the input supply.

Figure – 13 shows the output pulse obtained from the Darlington circuit, which remain at high state sufficient to operate any electromagnetic device. This output will go to low state in the next operation. In case the output of the above circuit is not sufficient, further enhancement can be done by means of including a TTL circuit in between the Darlington circuit & electromagnet relay coil. As shown in figure – 2, the coil of the electromagnetic device, which switches ON & OFF the motor load, gets the supply from the main line via the thermal overload relay NC (95 & 96 terminal) and “NO” of the low voltage dc electromagnet relay. The DC supply to the detector circuit is obtained from the line through an AC/DC voltage regulator circuit, as shown in figure – 2.

As explained above in the overview section of the invention the patent discloses about a modified circuit which is capable of switching magnetically latched device. In this case the transmitter circuit will be similar to that as explained above. However the detector circuit after the relay driving circuit is different to the earlier one. The supply to the control & driver circuit for the latched device is derived from a DC source via the “NO” interlocking contact of the low power relay (K1). Relay K3 gets energized, which changes its “NO” contact to “NC” to further provide supply to the relay K4, Timer T3 & T4 via resistor R15. “NC” contact of relay K3 changes its state to cut off supply to the latched device coil due to capacitor. The voltage supply is then fed to the D1 – R15-C1-R15 circuit, which makes the LED to blink for certain duration before the coil of latched device gets energized. Depending upon the duty cycle set for the monostable timer circuit (T4), after certain time delay power transistor turns ON, which energizes the relay driver circuit. Timer T4 being in monostable mode of operation, turns OFF the power transistor after the intended ON time. Hence the electromagnet of the latched device will get the supply for a brief time sufficient to switch it ON. In the subsequent next operation, when the dip switch of the transmitter circuit is pressed, will cause the output of the Darlington amplifier ULN2803 to low state thus cutting OFF supply to the Relay K1 and hence to the control & driver circuit for the latched device. Relay K3 drops down & hence resume its “NC” contact connected between the fully charged capacitor & latched device dc coil. The capacitor gets discharged across the dc coil but with a reverse voltage supply to drop down the magnetically latched electromagnet. The time duration of reverse voltage supply to the coil depends upon the time constant of the branch constituting R15 – C1 – R15.

Evidence demonstrating how the invention works
In order to check the functionality of the invention both the transmitter & detector circuit was developed in bread board as well as in PCB and tested with an electromagnetic device. When the dip switch is actuated, the electromagnetic devices gets switched ON & remain at that state until supply is fed to relay K1 & coil via the DC source & DC – DC converter. In the next operation when the dip switch is actuated the relay K1 drops down and hence supply to electromagnet coil gets cut off thereby switching OFF the electromagnetic device. While the device is in its ON state, when the dc supply gets cut off then the electromagnetic device switches OFF. Figure – 14 & 15 shows the test set up & performance of the circuit with AC electromagnetic device. Similar kind of performance can be expected with a magnetically latched or electric operator device.

Advantages
1. Low initial and running cost
2. It uses the same unit for switching ON and OFF operation
3. Continuity of service as damage to cable is completely eliminated
4. Delay in drop out of the electromagnetic device due to long cable capacitance is completely eliminated.
5. Problem associated with low voltage cable series & parallel arc are completely eliminated
6. Highly reliable system as compared to data and signal transfer through cable

We claim

1. An improved wireless system for electromagnetic actuation comprising :
transmitter unit;
detector unit;
wherein said transmitter unit comprising
enclosure means;
transmitter circuit comprising electronic module;
means for generating infrared electromagnetic waves;
means for transporting said infrared electromagnetic waves to said detector unit;
wherein said detector unit comprising
a triggering means so as to develop an inverted output signal providing a high ON time astable pulses;
means for latching and de-latching the said output signal; and
means for operating a conventional auxiliary electromagnetic device which further operates a conventional high power electromagnetic device.

2. System as claimed in claim 1 wherein said electronic module of the transmitter unit comprising DIP switch.

3. System as claimed in claim 1 wherein said electronic module of the transmitter unit comprising more than one ICs adapted to generate modulated higher frequency burst of pulses to drive said means for generating infrared electromagnetic waves.

4. System as claimed in claim 1 wherein said means for generating infrared electromagnetic waves comprising infrared frequency (IRF) LED means.

5. System as claimed in claim 4 wherein said IRF LED having maximum forward current of 100 mA at a voltage of about 1.3 to about 1.6 volts/

6. System as claimed in claims 4 and 5 wherein said IRF LED has radiant intensity of about 200 mW/sr.

7. System as claimed in claims 4 to 6 wherein said IRF LED has radiant power of about 35 mW.

8. System as claimed in claim 1 wherein said infrared electromagnetic waves having IRF ranging between 780 nm and 790 nm.

9. System as claimed in claim 1 wherein said infrared electromagnetic waves having carrier frequency ranging from about 38 KHz to about 40KHz.

10. System as claimed in claim 1 wherein said transmitter unit comprising battery operated DC source provided with an appropriate Ampere-hour.

11. System as claimed in claim 1 wherein said means for transporting said infrared electromagnetic waves to said detector unit comprising lens means.

12. System as claimed in claim 1 wherein said triggering means of said detector unit comprising inverted Schmitt trigger IC.

13. System as claimed in claim 1 wherein said means for latching and de-latching the said output signal comprising JK flip flop.

14. System as claimed in claim 1 wherein said detector unit is a photo detector.

15. System as claimed in claim 1 wherein said means for operating the high power electromagnetic device comprising Darlington amplifier.

16. System as claimed in claim 1 wherein said means for operating the high power electromagnetic device further comprising electromagnetic relay.

17. System as claimed in claim 1 wherein said detector unit optionally comprising TTL circuit.

18. System as claimed in claim 1 wherein said electromagnetic wave being optionally radio frequency electromagnetic wave.

19. An improved wireless system for electromagnetic actuation as herein substantially described and illustrated with reference to the accompanying drawings.