FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
A circuit breaker operating mechanism
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli,
Mumbai 400 030, Maharashtra, India, an Indian Company
Inventors
Vishal Vijay Bagade. Parag Prabhakar Khedkar and Shrikant Balkrishna Potnis of Crompton Greaves Ltd , S3 - Technology Department, Switchgear Complex, Ambad, Nasik-422010 Maharashtra, India, all Indian Nationals
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
This invention relates to a circuit breaker operating mechanism. BACKGROUND OF THE INVENTION
A conventional circuit breaker consists of a stationary contact and a movable contact. The movable contact moves relative to the stationary contact for facilitating opening and closing of the circuit breaker. The movement of the movable contact is actuated by an operating mechanism of the circuit breaker, which also controls the speed and automatic movement of the movable contact.
In an open position, the contacts of a circuit breaker are separated by a predetermined distance. The movable contact travels the predetermined distance in a direction towards the stationary contact to switch to a closed position. Similarly, to switch to an open position, the movable contact travels the predetermined distance in a direction away from the stationary contact.
For circuit breakers, inter alia, breaking/closing time is an important design consideration which has a direct effect on the life of the stationary and movables of the circuit breaker. The longer the breaking/closing time, the more the stationary and movables will be prone to damage due to arcing at the time breaking/closing the circuit breaker to which the stationary and fixed contacts are exposed to. To achieve a high speed movement of the movable of the circuit breaker, it is essential that the operating mechanism of the circuit breaker is tough, durable and reliable.
Conventionally, a spring pneumatic type operating mechanism is used in a circuit breaker in which spring energy is used to move the movable for closing the circuit breaker and pneumatic energy is used to move the movable to open the circuit breaker. Such an operating mechanism is prone to air leakage, bulky and not reliable.

It needs an air compressor to maintain high air pressure in the pneumatic circuit. The compressor is usually noisy, vibrative and prone to oil leakage.
In an another type of circuit breaker operating mechanism, a motor runs a complicated gear, ratchet pawl arrangement to charge the closing spring which in turn charges the tripping spring during closing operation. Construction of such a mechanism is extremely complicated. DETAILED DESCRIPTION OF THE INVENTION
According to the invention, there is provided a circuit breaker operating mechanism for moving a movable contact of a circuit breaker, the operating mechanism comprising a combustion chamber, an internal tank held within the combustion chamber for storing at least one chemical reactant therein, at least one external tank provided outside the combustions chamber for storing at least one chemical reactant therein which being adapted to be controllably dropped into the internal tank wherein said chemical reactants of said tanks react to produce hydrogen gas within the combustion chamber, a spark plug for igniting the hydrogen gas for increasing the gas pressure within the combustion chamber, a piston adapted to be thrusted against a spring within the combustion chamber consequent to said increase in the gas pressure, a transmission means for transmitting the movement of the piston to movable of the circuit breaker, the transmission means comprising a shaft, one end of which is connected to the piston and other end to one end of a lever pivoted at its center, the other end of the lever being connected to the movable contact of the circuit breaker, a latching mechanism connected to the shaft for locking the position of the shaft and a blower opening into the combustion chamber for blowing out the burnt hydrogen gas from the combustion chamber through an exhaust port in the combustion chamber.

These and other aspects, features and advantages of the invention will be better understood with reference to the following detailed description, accompanying drawings and appended claims, in which.
Fig la and lb, according to an embodiment of the invention, are schematic views of a circuit breaker operating mechanism depicting the operation of opening and closing the contacts of a circuit breaker.
Fig 2a and 2b, according to another embodiment of the invention, are schematic views of a circuit breaker operating mechanism depicting the operation of opening and closing the contacts of a circuit breaker.
As shown Fig la and lb according to an embodiment of the invention, a circuit breaker operating mechanism comprises of a cylindrical combustion chamber f held rigidly on a ground or a base. The combustion chamber 1 is usually made up of high strength metals such as steel etc and of a size of 5 to 25 liters for a circuit breaker of a rating of MV/ HV or EHV (i.e. right form 6 KV till 800 KV. A spring 2 is provided within the combustion chamber 1, one end 3 of which is seated on the inner surface of the base within the combustion chamber 1. On the other end 4 of the spring 2, a cylindrical piston 5 made up of metal such as steel is disposed as shown in the figures. The piston 5 is connected to one end 7 of a shaft 6 within the combustion chamber 1 whereas the other end 8 of the shaft 6 being disposed outside the combustion chamber 1 is connected to one end 10 of a lever 9 pivoted at its center; the other end 11 of the lever 9 is connected to a movable contact 12 of the circuit breaker. The shaft 6 along with the lever 9 is the transmission means which transfers the movement of the piston 5 into movement of the movable contact 12 of the circuit breaker. For locking/unlocking the position of the shaft 6, a latching mechanism (not shown) is connected thereto which is controlled by a circuit breaker control

mechanism. The compression strength of the spring 2 and/or the weight of the piston 5 is such that the spring 2 is not compressed by the dead weight of the piston 5 in the absence of any additional pressure on the piston 5. The side ends of the piston 5 and the corresponding inner surface of the walls of the combustion chamber 1 facing thereof are conditioned such that the piston 5 is adapted to be slid or moved along thereof. For example, a small gap is maintained between the side ends of the piston 5 and the corresponding inner surface of the walls of the combustion chamber 1 or if they are provided in contact, proper lubrication is ensured between the said contacts such that the piston 5 is unobstructedly slid along the inner surface of the walls of the combustion chamber 1. As shown in fig la, when the spring 2 is uncompressed, the shaft 6 remains locked through the latching mechanism and the piston 5 more or less remains at the centre of the combustion chamber 1 completely concealing/blocking the exhaust port 13 opening and blower opening 14 provided respectively at the middle of the opposite sidewalls of the combustion chamber 1. The blower opening 14 is connected to a blower 20 through a one way flow valve 22 whereas a normal valve is provided at the exhaust port 13. Also, when the spring 2 is uncompressed, the arrangement of the connection between the shaft 6, pivoted lever 9 and the movable contact 12 is such that the contacts of the circuit breaker are open. As shown in Fig lb, when the piston 5 is pushed downwards after unlocking the shaft 6 by the latching mechanism, the spring 2 is compressed and the shaft 6 is pulled downwardly which pushes the other end 11 of the lever 9 connected to the movable contact 12 of the circuit breaker to rotate anti clockwise thereby pushing the movable contact 12 towards the stationary contact 21 for closing the contacts of the circuit breaker. As shown in the Fig lb. upon movement of the piston 5 downwardly, the blower opening

14 and the exhaust port 13 are no longer being concealed by the side ends of the piston 5.
To thrust the piston 5 downwards after unlocking of the shaft 6 by the latching mechanism, very high gas pressure is generated in the area of the combustion chamber 1 above the piston 5. To generate such a high pressure, firstly hydrogen gas is generated in the combustion chamber 1 above the piston 5. Subsequently, it is ignited by means of a spark plug 15 opening into the combustion chamber 1 above the piston 5. Preferably, the spark plug 15 opens into the combustion chamber 1 at the roof thereof. The hydrogen gas is generated within the combustion chamber 1 by facilitating a chemical reaction of at least two chemical reactants within an internal tank 16 provided within the combustion chamber 1. Preferably, the internal tank 16 is held onto the inner surface of one of the side walls of the combustion chamber 1 and proximal to the roof of the combustion chamber 1. Preferably, the chemical reactants are pieces of metal such as iron and hydrochloric acid. However, there may be used other chemical reactants, chemical reaction of which generates hydrogen gas. The iron pieces are disposed in the internal tank 16 whereas the hydrochloric acid is stored in an external tank 17 provided outside the combustion chamber 1. The hydrochloric acid is adapted to be controllably injected/sprayed into the internal tank 16 onto the metal pieces for generating hydrogen gas. If more than two chemical reactants are involved, a second external tank is provided outside the combustion chamber 1 in which the third chemical reactant is stored and adapted to be controllably injected/sprayed/dropped into the internal tank 16. Preferably and as shown in Figs la and lb, the external tank 17 is held upside down and the acid therein is injected/sprayed into the internal tank 16 through a pipe 18 opening into the combustion chamber 1 at the roof thereof through a one-way flow valve 19. A circuit

breaker control mechanism (not shown) is connected to the valves of the external tank 17, blower 20 and the exhaust port 13 for controlling opening/closing thereof. If the circuit breaker control mechanism senses a condition which requires the circuit breaker contacts (12 & 21) to close, it sends a signal to the latching mechanism to unlock the shaft 6 and to the valve 19 of the external tank 17 to allow the hydrochloric acid therein to be injected/sprayed onto iron pieces in the internal tank 16. A chemical reaction of the iron pieces and hydrochloric acid occurs in the internal tank 16 which generates hydrogen gas within the combustion chamber 1. Thereafter, the circuit breaker control mechanism signals the spark plug 15 to ignite the hydrogen gas within the combustion chamber 1 which leads to a tremendous increase in the gas pressure which in turn leads to thrusting of the piston 5 downwardly. As described above. downwardly movement of the piston 5 leads to the spring 2 being compressed and closing of the contacts (12 & 21) of the circuit breaker. Subsequently, the latching mechanism locks the shaft 6 in its position while the spring 2 is compressed. As such any known latching mechanism may be used and is hence not described herein in detail. When the piston 5 is pushed downwardly, the blower opening 14 and the exhaust port 13 are no longer being concealed by the piston 5. As a result, the burnt hydrogen gas flows out of the combustion chamber 1 through the exhaust port 13. Additionally, the circuit breaker control mechanism signals the valve 22 connected to the blower 20 connected to the blower opening 14 to forcefully drive out all the burnt hydrogen gas within the combustion chamber 1 through the exhaust port 13. If the circuit breaker control mechanism decides to open the contacts (12 & 21) of the circuit breaker, it signals the latching mechanism to unlock the shaft 6 which results in the release of the spring 2 thereby driving the piston 5 upwardly. As described above, movement of the piston 5 upwardly results in an upward movement of the

shaft 6 which in turn rotates the lever 9 clock wise which in turn leads to pulling of the movable contact 12 of the circuit breaker connected thereto thereby opening of the contacts (12 & 21) of the circuit breaker.
As shown Fig 2a and 2b according to another embodiment of the invention, a circuit breaker operating mechanism comprises of a cylindrical combustion chamber 1 held rigidly on a ground or a base. The combustion chamber 1 is usually made up of high strength metals such as steel etc and of a size of 5 to 25 liters for a circuit breaker of a rating of MV/ HV or EHV (i.e. right form 6 KV till 800 KV). A spring 2 is disposed within the combustion chamber 1 between a piston 5 and the roof of the combustion chamber 1. A piston 5 is disposed within the combustion chamber 1 held onto one end 7 of the shaft 6; the other end 8 of the shaft 6 remaining disposed outside the combustion chamber 1 and connected to one end of 10 a lever 9 which is pivoted at its center; the other end 11 of the lever 9 being connected to a movable contact 12 of the circuit breaker. The shaft 6 along with the lever 9 is the transmission means which transfers the movement of the piston 5 into movement of the movable contact 12 of the circuit breaker. For locking/unlocking the position of the shaft 6, a latching mechanism (not shown) is connected thereto which is controlled by a circuit breaker control mechanism. A spring 2 is held between the piston 5 and the roof of the combustion chamber 1. The side ends of the piston 5 and the corresponding inner surface of the walls of the combustion chamber 1 facing thereof are conditioned such that the piston 5 is adapted to be slid or moved along thereof. For example, a small gap is maintained between the side ends of the piston 5 and the corresponding inner surface of the walls of the combustion chamber I or if they are provided in contact, proper lubrication is ensured between the said contacts such that the piston 5 is unobstructedly slid along the inner surface of the walls of the combustion chamber 1.

As shown in fig 2a, when the spring 2 is uncompressed, the shaft 6 remain locked through the latching mechanism and the piston 5 more or less remains at the centre of the combustion chamber 1 completely concealing/blocking the exhaust port 13 and blower opening 14 provided respectively at the middle of the opposite sidewalls of the combustion chamber 1. The blower opening 14 is connected to a blower 20 through a one way flow valve 22 whereas a normal valve is provided at the exhaust port 13. Also, when the spring 2 is uncompressed, the arrangement of the connection between the shaft 6, pivoted lever 9 and the movable contact 12 is such that the contacts (12 & 21) of the circuit breaker are closed. As shown in Fig 2b, when the piston 5 is pushed upwards after unlocking of the shaft 6 by the latching mechanism, the spring 2 is compressed and the shaft 6 connected to the piston 5 is pushed upwardly thereby rotating the pivot 5 in clockwise direction which leads to pulling of the movable contact 12 of the circuit breaker connected thereto to be pulled away from the stationary contact 21 0f the circuit breaker thereby opening the contacts (12 & 21) of the circuit breaker. As a result of the movement of the piston 5 upwardly, the blower opening 14 and the exhaust port 13 are no longer being concealed by the side ends of the piston 5.
To push the piston 5 upwards after unlocking of the shaft 6 by the latching mechanism, very high gas pressure is generated below the piston 5 in the combustion chamber 1. To generate such a high pressure, firstly hydrogen gas is generated in the combustion chamber1 below the piston 5. Subsequently, it is ignited by means of a spark plug 15 opening into the combustion chamber 1 below the piston 5. Preferably, the spark plug 15 opens at one of the sidewalls of the combustion chamber 1, The hydrogen gas is generated within the combustion chamber 1 by facilitating a chemical reaction of at least two chemical reactants within an internal tank 16 provided within

the combustion chamber 1. Preferably, the internal tank 16 is held onto the inner surface of one of the side walls of the combustion chamber 1 and proximal to the base of the combustion chamber 1. Preferably, the chemical reactants are pieces of metal such as iron and hydrochloric acid. However, there may be used other chemical reactants, chemical reaction of which generates hydrogen gas. The iron pieces are disposed in the internal tank 16 whereas the hydrochloric acid is stored in an external tank 17 provided outside the combustion chamber 1. The hydrochloric acid is adapted to be controllably injected/sprayed into the internal tank 16 onto the metal pieces for generating hydrogen gas. If more than two chemical reactants are involved, a second external tank is provided outside the combustion chamber 1 in which the third chemical reactant is stored and adapted to be controllably injected/sprayed/dropped into the internal tank 16. Preferably and as shown in Figs 2a and 2b, the external tank 17 is held upside down and the acid therein is injected/sprayed into the internal tank 16 through a pipe 18 opening into the combustion chamber 1 at one of the sidewalls thereof through a one-way flow valve 19. A circuit breaker control mechanism (not shown) is connected to the valves of the external tank 17, blower and the exhaust port 13 for controlling opening/closing thereof. If the circuit breaker control mechanism senses a condition which requires the circuit breaker contacts (12 & 21) to open, it sends a signal to the latching mechanism to unlock the shaft 6 and to the valve of the external tank 17 to allow the hydrochloric acid therein to be injected/sprayed onto the iron pieces in the internal tank 16. A chemical reaction of the iron pieces and hydrochloric acid occurs in the internal tank 16 which generates hydrogen gas within the combustion chamber 1. Thereafter, the circuit breaker control mechanism signals the spark plug 15 to ignite the hydrogen gas within the combustion chamber 1 which leads to a tremendous increase in the gas pressure which in turn leads to thrusting of

the piston 5 upwardly. As described above, movement of piston 5 upwardly leads to the spring 2 being compressed and opening of the contacts (12 & 21) of the circuit breaker. Subsequently, the latching mechanism locks the position of the shaft 6, As such any known latching mechanism may be used and is hence not described herein in detail. When the piston 5 is pushed upwardly, the blower opening 14 and the exhaust port 13 are no longer being concealed by the piston 5. As a result, the burnt hydrogen gas flows out of the combustion chamber 1 through the exhaust port 13. Additionally, the circuit breaker control mechanism signals the valve 22 connected to the blower 20 connected to the blower opening 14 to forcefully drive out all the burnt hydrogen gas within the combustion chamber 1 through the exhaust port 13. If the circuit breaker control mechanism decides to close the contacts of the circuit breaker, it signals the latching mechanism to unlock the shaft 6 which results in the release of the spring 2 thereby driving the piston 5 downwardly results in an downward movement of the shaft 6 which leads to an anti clockwise movement of the lever 9 which in turn leads to pushing of the movable contact 12 of the circuit breaker connected thereto towards the stationary contact 21 to close the contacts of the circuit breaker.
Preferably, the surface of the piston 5, inner surfaces of combustion chamber and internal tank 16 are provided with Teflon coating or similar protective coating to prevent reaction with acid. The circuit breaker control mechanism is a typical software based control mechanism used and hence is not described here in detail.
It will be appreciated by a person skilled in the art that the above embodiments are described with respect to a combustion chamber wherein the piston 5 is adapted to reciprocate vertically within the combustion chamber 1. If the piston 5 were to be reciprocated horizontally within the combustion chamber, consequential changes will be have to carried out within and outside the combustion chamber with regard to the

placement of the aforementioned components of the mechanism such as the spark plug 15 and the internal tank 16 open in the combustion chamber through one of the side walls thereof, the internal tank 16 being held onto the inner surface of said one of the side wall such that while the hydrogen gas is ignited within the combustion chamber, the piston 5 is thrusted against a spring 2 held onto the inner surface of the other side wall such that the piston 5 travels beyond the openings of the exhaust port 13 and openings of the blower, said openings of the blower being provided respectively at the middle of the roof and base of the combustion chamber. Subsequently, the movement of the piston 5 and the movable is so synchronized through the transmission means such that upon movement of the piston 5 horizontally towards one of the walls of the combustion chamber, the movable is moved to close or open its contact with the fixed contact of the circuit.
According to the invention, there is provided a circuit breaker operating mechanism which is simpler in construction, has fewer components and easy to operate without much manual intervention.
Although the invention has been described with reference to a specific embodiment, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiment, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such modifications can be made without departing from the scope of the invention as defined in the appended claims.

We claim:
1. A circuit breaker operating mechanism for moving a movable contact of a circuit breaker, the operating mechanism comprising:
a. a combustion chamber;
b. an interna] tank held within the combustion chamber for storing at least
one chemical reactant therein;
c. at least one external tank provided outside the combustions chamber
for storing at least one chemical reactant therein which being adapted
to be controllably dropped into the internal tank wherein said chemical
reactants of said tanks react to produce hydrogen gas within the
combustion chamber;
d. a spark plug for igniting the hydrogen gas for increasing the gas
pressure within the combustion chamber;
e. a piston adapted to be thrusted against a spring within the combustion
chamber consequent to said increase in the gas pressure;
f. a transmission means for transmitting the movement of the piston to
movable of the circuit breaker, the transmission means comprising a
shaft, one end of which is connected to the piston and other end to one
end of a lever pivoted at its center, the other end of the lever being
connected to the movable contact of the circuit breaker;
g. a latching mechanism connected to the shaft for locking the position of
the shaft; and
h. a blower opening into the combustion chamber for blowing out the burnt hydrogen gas from the combustion chamber through an exhaust port in the combustion chamber.

2. The circuit breaker operating mechanism as claimed in claim 1, wherein a one- way flow valve is provided at the opening of the blower and external tank and a valve is provided at the opening of the exhaust port into the combustion chamber,
3. The circuit breaker operating mechanism as claimed in claim 1, wherein the piston is adapted to reciprocate vertically within the combustion chamber.
4. The circuit breaker operating mechanism as claimed in claim 3, wherein the spark plug and the external tank open into the combustion chamber at the roof thereof, the internal tank being held onto the inner surface one of the sidewalls of the combustion chamber proximally to the roof of the combustion chamber such that while the hydrogen gas is ignited within the combustion chamber, the piston is thrusted against a spring held on the base of the combustion chamber such that the piston travels beyond the exhaust port and blower opening, the exhaust port and blower opening being provided respectively at the middle of the opposite sidewalls in the combustion chamber.
5. The circuit breaker operating mechanism as claimed in claim 3, wherein the spark plug and the external tank open in the combustion chamber at one of the sidewalls thereof proximally to the base of the combustion chamber, the internal tank being seated on the base such that when the hydrogen gas is ignited within the combustion chamber, the piston is thrusted upwardly against a spring held between the roof of the combustion chamber and the piston such

that the piston travels beyond the exhaust port and blower opening, said exhaust port and blower opening being provided respectively at the middle of the opposite sidewalls in the combustion chamber.
6. The circuit breaker as claimed in claim 1, wherein the piston is adapted to reciprocate horizontally within the combustion chamber.
7. The circuit breaker operating mechanism as claimed in claim 6, wherein spark plug and the internal tank open in the combustion chamber through one of the side walls thereof, the internal tank being held onto the inner surface of said one of the side wall such that while the hydrogen gas is ignited within the combustion chamber, the piston is thrusted against a spring held onto the inner surface of the other side wall such that the piston travels beyond the exhaust port and blower opening, the exhaust port and blower opening being provided respectively at the middle of the roof and base of the combustion chamber.
8. The circuit breaker operating mechanism as claimed in claim 3. wherein the movement of the piston and the movable is so synchronized through the transmission means such that upon movement of piston downwardly/upwardly, the movable is moved to open/close its contact with the fixed contact of the circuit breaker or vice versa.
9. The circuit breaker operating mechanism as claimed in claim 6, wherein the movement of the piston and the movable is so synchronized through the transmission means such that upon movement of the piston horizontally

towards one of the walls of the combustion chamber, the movable is moved to close or open its contact with the fixed contact of the circuit.
10. The circuit breaker operating mechanism as claimed in claim 1, wherein the chemical reactant within the internal and external tank are metal pieces and hydrocholic acid respectively.
11. The circuit breaker operating mechanism as claimed in claim 10, wherein the metal pieces are iron pieces.