FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
AND
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 spur gear based drive mechanism for spring loaded circuit breakers.
APPLICANTS:
Crompton Greaves Limited, CG House, Dr. Annie Besant Road, Worli, Mumbai - 400030, Maharashtra, India, an Indian Company
INVENTOR:
Teli Kunal, Roy Deosharan, Isai Sagar and Gupta Vijendra; all of Crompton Greaves Limited, Global R&D, Bhaskara Building, Kanjur Marg (East), Mumbai - 400042, Maharashtra, India; all Indian Nationals.
PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

FIELD OF THE INVENTION:
This invention relates to the field of mechanical engineering.
Particularly, this invention relates to switchgear equipment and circuit breakers.
More particularly, this invention relates to circuit breaker drive mechanism.
Specifically, this invention relates to a spur gear based drive mechanism for spring loaded circuit breakers.
BACKGROUND OF THE INVENTION:
Electrical loads, devices, circuits, assemblies, and connections may be subjected to electrical fluctuations or short-circuit due to interruptions in power supply or over load or under load. In any of these circumstances, the load or device is subjected to breakdown if the surges are not effectively prevented from acting on them. One way is to ensure seamless supply. Another way is to monitor the aberrations, and in case of faults, simply break the electrical connection.
The term 'switchgear', used in association with electric power systems, or grids, or power transmission systems and networks refers to combination of electrical disconnects, fuses, and/or circuit breakers used to isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to be done and to clear faults
Circuit Breaker mechanisms are a type of switchgear equipment which are used in electrical equipment, as an adjunct mechanism, for preventing said electrical equipment from current / voltage aberrations such as overload, short circuit, underload, or the like. Basically, it is designed to detect a fault condition, and operates to interrupt the working of the associated electrical equipment upon detection, thereby saving its health.
Circuit breakers provide the breaking of power supply upon detection of faulty electrical conditions in the operation of associated assemblies. Thus, a circuit breaker acts as a safety

device for said associated assemblies. As sensitivity of associated assemblies increase, it becomes imperative that circuit breakers be absolutely reliable in their working as a safeguard feature. Moreover, it is more essential that they act within specified time durations, in order to actuate its working upon detection of fault.
Once a fault is detected, contacts within the circuit breaker must open to interrupt the circuit; some mechanically-stored energy (using resilient mechanisms such as springs or compressed air) contained within the breaker is used to separate the contacts. Small circuit breakers may be manually operated; larger units have coils: trip coils to trip the mechanism; close coils to close the mechanism; and electric motors to restore energy to the springs.
It has been a constant endeavour to improve this specified time durations by attempting to reduce the time between detection and actuation. Since actuation is a mechanical process involving mechanical parts, its change of state from rest to motion is a crucial time consuming factor. This time duration to overcome inertia is a measure of goodness of the circuit breaker.
Furthermore, it is also imperative that a discharged circuit breaker be efficiently restored to its charged condition ready to be actuated upon detection of a fault. This requires aiding the mechanical storage of energy (using resilient mechanisms such as springs or compressed air) which further trigger the trip coils and / or close coils upon detection of a fault. In its charged condition, a latch mechanism is used to latch the moving parts in its energy-stored condition -ready to be triggered in to action.
The term, 'overtravel' relates to the excess travelling energy in the moving components which result in circuit breaker operation. Overtravel may lead to unnecessary stress in the components consisting of the latching system. Due to high impact load on circuit breaker system, reliability of components is decreased and some failures observed.
A trip coil is a type of solenoid in which the moving armature opens a circuit breaker or other protective device when the coil current exceeds a predetermined value. A closing coil is adapted to shut the circuit breaker completely.

In its working mode, if a power surge occurs in the electrical system, the breaker will trip. This means that a breaker that was in the "on" position will flip to the "off" position and shut down the electrical power leading from that breaker. Essentially, a circuit breaker is a safety device. When a circuit breaker is tripped, it may prevent a fire from starting on an overloaded circuit; it can also prevent the destruction of the device that is drawing the electricity.
A close coils is a coil which closes the circuit breaker electrically using an external voltage source when a specified voltage is applied across the coil.
The operating mechanism, of a circuit breaker, consists primarily of two tension springs; 1) tripping spring; and 2) closing spring. The closing spring generates the required driving force to close the circuit breaker and charge the tripping spring. The tripping spring is directly connected to the circuit breakers link system. This means that the mechanical energy needed for the vital opening operation is always stored in the tripping spring when the circuit breaker is in closed position. In other words, a closed circuit breaker is always prepared for immediate opening.
A motor drives the spring charging gear, which automatically charges the closing spring immediately after each closing operation. The springs are kept in charged state by a latch that is released when the circuit breaker is being closed. This enables rapid reclosing of the circuit breaker after a pre-defined dead time interval.
PRIOR ART;
Circuit breakers perform the function of energizing and de-energizing the loads in normal operational condition. In conditions such as a short circuit or sustained overload they can be used to rapidly disconnect the circuit. To perform the function of rapid connection and disconnection of circuits the drive mechanisms of contacts of circuit breakers would need to store energy in some form. One of the forms in which the energy can be stored and rapidly utilized is by storing the energy in springs.
While performing any operation the stored energy of the spring would need to be used and simultaneously the spring would need to be re-energized for subsequent operations. While performing the process of re-energizing the spring, it is important to ensure that the spring is not

overcharged. There are different mechanisms available for performing the function of reenergizing the spring.
According to the prior art, ratchet-pawl mechanisms are used for charging spring. In these mechanisms, teeth are not cut on full periphery of ratchet wheel. Charging takes place only when the pawl engages and pushes where the tooth is present on the ratchet wheel, thus rotating the ratchet wheel. This results in charging of spring. But when pawl comes in contact with uncut teeth periphery of ratchet wheel, pawl is unable to rotate ratchet wheel since there are no teeth to engage. This prevents the spring from being overcharged in ratchet pawl mechanisms.
Since, these mechanisms are used in very high current ratings, therefore, the teeth on the outer periphery of the ratchet wheel is prone to damages, thereby preventing the effective operation of such mechanisms and resulting in probable overcharging.
Circuit breaker systems of the prior art were riddled with problems and disadvantages, as listed below:
1. Ratchet wheel becomes bulky when higher energy is required to be stored in spring;
2. Manufacturing of ratchet wheel is costly;
3. Teeth on ratchet wheel are prone to failure (due to the single line contact between ratchet and pawl)
EP1369886 discloses a toothed wheel which rotates with a spring, moving between two angular positions. A smaller gear wheel moves between two angular positions. The main toothed wheel has a retractable section forming a constant path. However, this is a ratchet mechanism and succumbs to the disadvantages, cited above.
EP0881652 discloses switchgear with a retracting tooth portion. However, this is also a ratchet mechanism and succumbs to the disadvantages, cited above.
Hence, there is a need for a mechanism which obviated the limitations of the prior art.

OBJECTS OF THE INVENTION:
An object of the invention is to provide high energy circuit breaker mechanisms in high voltage switchgears.
Another object of the invention is to provide high energy circuit breaker mechanisms in high voltage switchgears where spur gear is used for charging and discharging of closing spring.
Yet another object of the invention is to provide high energy circuit breaker mechanisms in high voltage switchgears where number of linkages is reduced.
Still another object of the invention is to prevent failure of spur gear due to impact load.
An additional object of the invention is to improve reliability of charging system.
Yet another additional object of the invention is to eliminate criticality of assembly.
Still another additional object of the invention is to reduce cost of circuit breaker mechanism.
An additional object of the invention is to prevent overcharging, in circuit breakers, by using a designed protrusion mechanism.
Yet an additional object of the invention is to achieve integration of charging ratchet and stopper wheel for high energy mechanisms in high voltage switchgears.
An additional object of the invention is to provide a spring charging system which can be used for low energy and low voltage switchgear mechanisms as well as for high energy and high voltage switchgear mechanisms.

SUMMARY OF THE INVENTION:
According to this invention, there is provided a spur gear based drive mechanism for spring loaded circuit breakers, said mechanism comprising:
a. at least a spur gear adapted to be coupled with a closing spring and further adapted to
provide momentum for charging and discharging of said closing spring of said spring
loaded circuit breaker, characterised, in that, an operative forward / anticlockwise
angular displacement of said spur gear for a first hemi-circular arc starting charging
of said closing spring and a further operative forward / anticlockwise angular
displacement of said spur gear for a second (remainder) hemi-circular causing
complete charging and discharging of said closing spring;
b. at least a spring crank adapted to be co-axially coupled to said spur gear with at least
a spline shaft, said spring crank advantageously coupled with a closing spring adapted
to facilitate said closing spring's charging;
c. at least a charging crank adapted to be advantageously coupled, and co-axially
aligned, to said spring crank by said spline shaft;
d. at least a spring loaded protrusion adapted to be located on said charging spur gear,
said protrusion being a block with a first operative slope on operative top of the block
in a first direction, and further with a second operative slope on operative top of said
block in a second direction, said first slope and said second slope, sloping away from
each other, characterized, in that, a contact face on said protrusion helps in latching
said spring loaded protrusion with said charging crank, and the first slope helps in
pushing said spring loaded protrusion into its slot by said latch plate; and
e. at least a latch plate adapted to push in said spring loaded protrusion to avoid the
overcharging.
Typically, said spur gear is a worm wheel or a wheel with spokes.
Typically, said spring crank is an elongate member which extends from spur gear centre, radially, towards the circumferential edge of the spur gear.

Typically, said mechanism comprises a chain adapted to connect said spring crank to a lower plate to which a closing spring is affixed at its one end.
Typically, said closing spring being affixed to a lower plate at its one end and to an upper plate at its other end.
Typically, said charging crank is a pre-designed plate adapted to be co-axially fixed on the spline shaft such that said charging crank, said spring crank, and said spur gear are co-axially aligned.
Typically, said charging crank is located between said spur gear and said spring crank.
Typically, said spring loaded protrusion sits on a resilient means such as a spring, characterized in that, said spring loaded protrusion, in at least one working embodiment is in a spring compressed mode, and said spring loaded protrusion, in at least one working embodiment is in a spring decompressed mode.
Typically, said spring loaded protrusion comprises an operative bottom surface which rests on a resilient means and makes it spring loaded, in nature.
Typically, said spring loaded protrusion is located in a slot or a recess provided on said charging spur gear's flat side.
Typically, said latch plate is a rigid circumferentially located hemi-circular arced plate which is located at the circumference of said spur gear and spaced apart from said spur gear, characterized, in that, said spaced apart distance coincides with the pushed out height of said spring loaded protrusion, in that, said hemi-circular arced plate pushes the spring loaded protrusion on said spur gear as said spur gear angularly displaces along one half of its full angular displacement cycle.
Typically, said second operative slope on said operative top of said block is adjacent to said first operative slope in a second direction.
Typically, said first slope width is relatively lesser than said second slope width.

Typically, said mechanism comprises two spring loaded protrusions, each located diametrically across the other.
Typically, said mechanism comprises at least a motor adapted to be connected to said charging spur gear through gear train in an operative forward / anticlockwise direction.
Typically, said mechanism comprises at least a bearing between said spline shaft and said charging spur gear, so that both can be angularly displaced, independently.
Typically, said charging spur gear is adapted to drive said charging crank only when said spring loaded protrusion is out of said slot on said charging spur gear in decompressed mode.
Typically, said charging spur gear is adapted to not transmit any motion to said charging crank when said protrusion is inside said slot on said charging spur gear in compressed mode.
Typically, said spline shaft, said charging crank, and said spring crank are always angularly displaced together.
Typically, said mechanism comprises a chain adapted to connect said closing spring to said spring crank.
Typically, said mechanism comprises said closing spring adapted to be placed between an upper plate and a lower plate, where said lower plate is a moving end and said upper plate is a stationary end.
Typically, said charging crank and said spring crank angularly displace together through said spline shaft connection and said protrusion, thus charging the said closing spring.
Typically, said mechanism comprises at least a latch adapted to lock said charging crank in spring charged condition.

Typically, said mechanism comprising a motor adapted to drive said spur gear, characterized, in that, said latch plate adapted to press said spring loaded protrusion inside said charging spur gear when motor is not stopped.
Typically, in latched condition, said latch plate is such that said spring loaded protrusion adapted to come into contact with said latch plate as said protrusion angularly displaces along with said charging spur gear, characterized, in that, said latch plate adapted to push said protrusion inside said charging spur gear due to said operative first slope provided on said protrusion.
Typically, said mechanism comprises a motor adapted to drive said spur gear, characterized, in that, said latch plate adapted to press said spring loaded protrusion inside said charging spur gear when motor is not stopped.
Typically, said mechanism comprises at least a latch adapted to be triggered in order to angularly displace said charging crank and said spring crank in an operative forward anticlockwise direction in order to release stored energy from said closing spring.
Typically, in released condition, said charging crank presses spring loaded protrusion inside when it crosses the spring loaded protrusion and it slides over said second slope present on said protrusion, characterized, in that, said charging crank is adapted to be angularly displaced freely without damaging the protrusion.
Typically, said mechanism comprises at least two spring loaded protrusions are adapted to be alternatively carrying the charging crank in successive cycles of charging operations.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which: Figure 1 illustrates the closing spring in discharged condition; Figure 1A illustrates enlarged view of section B of Figure 1;

Figure 1B illustrates view along section A-A of Figure I;
Figure 2A illustrates the contact separation between protrusion and charging crank;
Figure 2B illustrates enlarged view without spring crank;
Figure 3A illustrates a view when latch plate presses the protrusion inside the slot to avoid overcharging;
Figure 3B illustrates enlarged view without charging crank:
Figure 3C illustrates spring loaded protrusion; and
Figure 4 illustrates another view of spur gear based drive mechanism for spring loaded circuit breakers.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
According to this invention, there is provided a spur gear based drive mechanism for spring loaded circuit breakers.
Figure 1 illustrates the construction of the operating mechanism of charging system.
In accordance with an embodiment of this invention, there is provided a spur gear 2 or worm wheel adapted to be used for charging a closing spring. This spur gear or worm wheel is charging spur gear. Typically, the charging spur gear may also be a wheel with spokes.
In accordance with another embodiment of this invention, there is provided a spring crank 7 adapted to connect spring to spring crank. Typically, the spring crank is an elongate member which extends from spur gear centre, radially, towards the circumferential edge of the spur gear. A spline shaft 3 is adapted to co-axially locate spring crank over spur gear. A chain 9 connects

the spring crank to a lower plate 11 to which a closing spring 8 is affixed at its one end. The closing spring 8 is affixed to the upper plate 10 at its other end.
In accordance with yet another embodiment of this invention, there is provided a charging crank 4. The spring crank is attached to the charging crank by the spline shaft. Typically, the charging crank is a pre-designed plate adapted to be co-axially fixed on the spline shaft such that the charging crank, spring crank, and spur gear are co-axially aligned. Typically, the charging crank is located between the spur gear and the spring crank.
In accordance with still another embodiment of this invention, there is provided at least a spring loaded protrusion 5 adapted to be located on the charging spur gear. Typically, the protrusion sits on a resilient means such as a spring 6. The spring loaded protrusion, in at least one working embodiment is in a spring compressed mode. The spring loaded protrusion, in at least one working embodiment is in a spring decompressed mode. The charging spur gear is adapted to drive charging crank only when the protrusion is in spring decompressed mode. When the protrusion is in spring compressed mode, charging cannot take place and therefore, overcharging is avoided. Typically, there are two spring loaded protrusions 5.1 and 5.2, each located diametrically across the other. The use of two protrusions reduces charging time. The protrusion is a block with a first operative slope (slope A) on operative top of the block in a first direction. Further, the protrusion is a block with a second operative slope on the operative top of the block, adjacent the first operative slope (slope B) in a second direction. Typically, the first slope and the second slope, slope away from each other. The operative bottom of the block rests on resilient means such as spring and makes it spring loaded, in nature. Typically, the spring loaded protrusion is located in a slot or a recess provided on the charging spur gear's flat side. A contact face (face C) on the protrusion helps in latching the spring loaded protrusion with the charging crank. The first slope helps in pushing the spring loaded protrusion into its slot by the latch plate. The second slope also helps in pushing the spring loaded protrusion into its slot by the charging crank during discharging.
In accordance with an additional embodiment of this invention, there is provided a latch plate 12 adapted to push in the spring loaded protrusion when the closing spring is fully charged. The latch plate, typically, is a rigid circumferentially located hemi-circular arced plate which is

located at the circumference of the spur gear and spaced apart from the spur gear. The spaced apart distance coincides with the pushed out height of the spring loaded protrusion, in that, the hemi-circular arced plate pushes the spring loaded protrusion on the spur gear as the spur gear angularly displaces along one half of its full angular displacement cycle. Initially, the spring loaded protrusion is out from under the latch plate, and the first half angular displacement of the spur gear starts, and charging of the closing spring starts. As the spring loaded protrusion comes in to contact with the latch plate, during the start of the second half of full angular displacement, the protrusion is pushed in to the recess / slot as it is spring loaded, and charging of closing spring stops. The spring loaded protrusion continues to be pushed into its slot under the hemi-circular arced plate.
Motor 1 is connected to charging spur gear 2 through gear train since high torque is required for charging. Motor 1 drives charging spur gear 2 in an operative forward / anticlockwise direction. There is a bearing between spline shaft 3 and charging spur gear 2, so that both can be angularly displaced, independently. The spring loaded protrusion 5 is provided on the charging spur gear 2 and it can move in and out in the slot provided on charging spur gear 2. The charging spur gear 2 will drive the charging crank 4 only when the spring loaded protrusion 5 is out of the slot on charging spur gear 2 i.e. in decompressed mode. There is a surface contact between protrusion 5 (face C) and charging crank 4 when they are connected to each other. Charging spur gear 2 will not transmit any motion to charging crank 4 when the protrusion 5 is inside the slot i.e. in compressed mode. Hence, charging crank 4 and charging spur gear 2 get connected or disconnected depending on the position of the spring loaded protrusion 5. Charging spur gear 2 comprises, ideally, two protrusions, 5.1 and 5.2 placed 180 degree apart from each other. When it comes in contact with the charging crank 4, both will rotate simultaneously. There is a return spring 6 inside the slot provided on charging spur gear 2 (as shown in figure 1-Section A-A), pushing protrusion 5 outwards. Charging crank 4 and spring crank 7 are connected together through spline shaft 3. Therefore, spline shaft 3, charging crank 4, and spring crank 7 are always angularly displaced together. Closing spring 8 is connected to spring crank 7 by chain 9. Closing spring 8 is placed between upper plate 10 and lower plate 11, where lower plate 11 is moving end and upper plate 10 is stationary end. Lower plate 11 is connected to chain 9. Latch plate 12 is fixed to a rigid structure, which is used to push the protrusion 5 inside the slot.

Figure 1 illustrates the closing spring 8 in discharged condition. While charging operation (storing energy in spring), motor 1 drives charging spur gear 2 in anticlockwise direction through a series of gear pairs. At this moment, the return spring 6 pushes the protrusion 5.1 outwards and thus helps to rotate the charging crank 4. The charging crank 4 and spring crank 7 rotate together through spline shaft 3 connection and charge the closing spring 8. There is an opposing torque in clockwise direction due to closing spring 8 until the line of action of chain 9 crosses the centre of spline shaft 3. As shown in Figure 2, of the accompanying drawings, once the line of action of chain 9 crosses the centre of spline shaft 3, there is a reversal in direction of closing spring 8 torque. This helps to angularly displace the spring crank 7 and charging crank 4 in an operative forward / anticlockwise direction independent of charging spur gear 2. The charging crank 4 is locked by latch 13 as charging is complete (as shown in Fig.3). Figure 3A shows the contact separation between protrusion 5.1 and charging crank 4. It is to be noted that on the other side, the protrusion 5.2 is kept pressed inside the slot on the charging spur gear 2 due to the latch plate 12 when protrusion 5.1 is pushing the charging crank 4 while charging (as shown in Figure 2B).
Since, latch 13 has locked the rotation of charging crank 4, energy remains stored in the closing spring 8. In normal condition, a limit switch (not shown in the figures) stops motor 1. But, if in case the limit switch fails or the motor 1 does not stop due to any reason, then the protrusion 5.1 may push the charging crank in the absence of latch plate 12. This action can damage the mechanism because latch 13 is in engaged condition with charging crank 4 and will oppose the gear (motor 1) rotation. Latch plate 12 is provided to avoid this damage (or prevent overcharging). Latch plate 12 is fixed to a rigid structure. So, if the motor 1 is not stopped after full charging of closing spring 8, the protrusion 5.1 angularly displaces along with the charging spur gear 2. In latched condition, the position of latch plate 12 is such that the protrusion 5.1 (slope A) will come into contact with latch plate 12 as the protrusion 5.1 rotates along with the charging spur gear 2. The latch plate 12 pushes the protrusion 5.1 inside the charging spur gear 2 due to the slope A (first slope) provided on the protrusion 5.1 as shown in Figure 3B. The protrusion 5 never comes in contact with charging crank 4 in latched condition (spring in fully charged state) since it is kept pressed inside by the latch plate 12. This helps to prevent the overcharging as shown in Figure 3A.

In normal latched condition, motor 1 will be stopped. In this position, spring loaded protrusion 5.2 is pressed inside the charging spur gear 2 by the latch plate 12. When latch 13 is triggered, charging crank 4 and spring crank 7 angularly displaces together in same direction (anticlockwise). This action helps in releasing the stored energy in closing spring 8. The charging spur gear 2 is stationary during this action. Since the spring loaded protrusion 5.2 is pressed inside the charging spur gear 2, the charging crank 4 crosses the spring loaded protrusion 5.2 without getting in contact with it. After the closing spring 8 is fully discharged, the charging crank 4 is stopped by some arrangement (not shown in the figures). In case the motor 1 is not stopped at the position shown in Figure 3A and 3B, the spring loaded protrusion 5.2 will not be in contact with latch plate 12. So, in this case, the spring loaded protrusion 5.2 comes outside the charging spur gear 2. If the latch 13 is released in such condition, the charging crank 4 is free to rotate. The charging crank 4 presses spring loaded protrusion 5.2 inside when it crosses the spring loaded protrusion 5.2. It slides over the slope B (second slope) present on the protrusion 5.2. Slope B (second slope) is provided on spring loaded protrusion 5 to avoid damage in such abnormal conditions. Thus charging crank 4 can be angularly displaced freely without damaging the protrusion 5 as shown in Figure 4.
In the next cycle of charging, spring loaded protrusion 5.2 will carry the charging crank 4. So, in normal conditions, the protrusions 5.1 and 5.2 will alternately carry the charging crank 4 in successive cycles of charging operations.
The technical advancement of this invention lies in provisioning a spur gear drive mechanism adapted to work with a specially designed spring loaded protrusion adapted to engage with a latch plate for avoiding overcharging / overtravel.
While this detailed description has disclosed certain specific embodiments of the present invention for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim,
1. A spur gear based drive mechanism for spring loaded circuit breakers, said mechanism
comprising:
a. at least a spur gear adapted to be coupled with a closing spring and further
adapted to provide momentum for charging and discharging of said closing spring
of said spring loaded circuit breaker, characterised, in that, an operative forward /
anticlockwise angular displacement of said spur gear for a first hemi-circular arc
starting charging of said closing spring and a further operative forward /
anticlockwise angular displacement of said spur gear for a second (remainder)
hemi-circular causing complete charging and discharging of said closing spring;
b. at least a spring crank adapted to be co-axially coupled to said spur gear with at
least a spline shaft, said spring crank advantageously coupled with a closing
spring adapted to facilitate said closing spring's charging;
c. at least a charging crank adapted to be advantageously coupled, and co-axially
aligned, to said spring crank by said spline shaft;
d. at least a spring loaded protrusion adapted to be located on said charging spur
gear, said protrusion being a block with a first operative slope on operative top of
the block in a first direction, and further with a second operative slope on
operative top of said block in a second direction, said first slope and said second
slope, sloping away from each other, characterized, in that, a contact face on said
protrusion helps in latching said spring loaded protrusion with said charging
crank, and the first slope helps in pushing said spring loaded protrusion into its
slot by said latch plate; and
e. at least a latch plate adapted to push in said spring loaded protrusion to avoid the
overcharging.
2. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in
claim 1, wherein said spur gear is a worm wheel or a wheel with spokes.

3. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said spring crank is an elongate member which extends from spur gear centre, radially, towards the circumferential edge of the spur gear.
4. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said mechanism comprising a chain adapted to connect said spring crank to a lower plate to which a closing spring is affixed at its one end.
5. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim I, wherein said closing spring being affixed to a lower plate at its one end and to an upper plate at its other end.
6. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said charging crank is a pre-designed plate adapted to be co-axially fixed on the spline shaft such that said charging crank, said spring crank, and said spur gear are co-axially aligned.
7. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said charging crank is located between said spur gear and said spring crank.
8. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said spring loaded protrusion comprising an operative bottom surface which rests on a resilient means and makes it spring loaded, in nature.
9. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said spring loaded protrusion is located in a slot or a recess provided on said charging spur gear's flat side.
10. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said spring loaded protrusion sits on a resilient means such as a spring, characterized in that, said spring loaded protrusion, in at least one working embodiment is

in a spring compressed mode, and said spring loaded protrusion, in at least one working embodiment is in a spring decompressed mode.
11. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said latch plate is a rigid circumferentially located hemi-circular arced plate which is located at the circumference of said spur gear and spaced apart from said spur gear, characterized, in that, said spaced apart distance coincides with the pushed out height of said spring loaded protrusion, in that, said hemi-circular arced plate pushes the spring loaded protrusion on said spur gear as said spur gear angularly displaces along one half of its full angular displacement cycle.
12. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said second operative slope on said operative top of said block is adjacent said first operative slope in a second direction.
13. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said mechanism comprising two spring loaded protrusions, each located diametrically across the other.
14. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said mechanism comprising at least a motor adapted to be connected to said charging spur gear through gear train in an operative forward / anticlockwise direction.
15. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said mechanism comprising at least a bearing between said spline shaft and said charging spur gear, so that both can be angularly displaced, independently.
16. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said charging spur gear adapted to drive said charging crank only when said spring loaded protrusion is out of said slot on said charging spur gear in decompressed mode.

17. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said charging spur gear adapted to not transmit any motion to said charging crank when said protrusion is inside said slot on said charging spur gear in compressed mode.
18. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said mechanism comprising a chain adapted to connect said closing spring to said spring crank.
19. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said mechanism comprising said closing spring adapted to be placed between an upper plate and a lower plate, where said lower piate is a moving end and said upper plate is a stationary end.
20. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said charging crank and said spring crank angularly displace together through said spline shaft connection and said protrusion, thus charging the said closing spring.
21. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said mechanism comprising at least a latch adapted to lock said charging crank in spring charged condition.
22. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said mechanism comprising a motor adapted to drive said spur gear, characterized, in that, said latch plate adapted to press said spring loaded protrusion inside said charging spur gear when motor is not stopped.
23. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein in latched condition, said latch plate being such that said spring loaded protrusion adapted to come into contact with said latch plate as said protrusion angularly displaces along with said charging spur gear, characterized, in that, said latch plate adapted

to push said protrusion inside said charging spur gear due to said operative first slope provided on said protrusion.
24. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said mechanism comprising at least a latch adapted to be triggered in order to angularly displace said charging crank and said spring crank in an operative forward anticlockwise direction in order to release stored energy from said closing spring.
25. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein in released condition, said charging crank presses spring loaded protrusion inside when it crosses the spring loaded protrusion and it slides over said second slope present on said protrusion, characterized, in that, said charging crank adapted to be angularly displaced freely without damaging the protrusion.
26. The spur gear based drive mechanism for spring loaded circuit breakers as claimed in claim 1, wherein said mechanism comprising at least two spring loaded protrusions are adapted to be alternatively carrying the charging crank in successive cycles of charging operations.