FORM2
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 ACTUATION ARRANGEMENT FOR USE IN CIRCUIT BREAKERS
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 an actuation arrangement of circuit breakers. More particularly, the invention is concerned about an improved actuation arrangement for use in circuit breakers having a direct actuation for ready to Close condition.
BACKGROUND OF THE INVENTION
Circuit breakers have a mechanism for performing the ON and OFF operation. The position in which the Main contacts are in closed condition is called the ON position while the position in which Main contacts are in open condition is called OFF position.
The mechanism used is stored energy type wherein the energy stored in a spring is used for closing operation. This spring is called the "Main spring" or "Closing Spring". The spring in "charged condition" is held by a Closing latch. Upon release of this closing latch, the spring energy gets released and is used for turning ON the Circuit Breaker. Similarly, for turning OFF the Circuit breaker, a spring known as "Opening spring" or "Return spring" is used. This spring is charged when the circuit breaker is turned ON. The energy stored in this spring is used for opening operation, Hence, for closing operation (ON), it is necessary that the "Main spring" or "Closing spring" should be "charged".
Apart from charged condition of main spring, other conditions required to be fulfilled for making the breaker ON are:
1. Racking shutter should be closed,
2. Rated supply should be given to Under Voltage release.
3. Arc chutes should be mounted properly,
4. Flux Shift Device should be in reset condition
5. No signal from mechanical interlock, if breaker is mechanically interlocked and
6. Breaker should be OFF.
After fulfillment of all above conditions, the breaker is said to be "Ready to Close". The above conditions can also be called "interlocks".

US 6144002 discloses a switchgear apparatus having at least one movable contact biased in an open position by an opening spring, a loading mechanism of a closing spring and a kinematic opening and closing system linking the closing spring, the movable contact and the opening spring. The system is controlled by an opening latch and a closing latch. A closing order can be validly transmitted only to the closing latch when the apparatus is in a "ready to close" state, i.e. open, loaded and without a permanent opening order. The switchgear apparatus has an indicator with three positions: a "not loaded" position, a "ready to close"position and a third"loaded and not ready to close" or "loaded disengaged" position. The indicator is kinematically linked to the loading mechanism, the opening latch, and the movable contact.
US 6788172 discloses a device for controlling the closing of a power circuit breaker according to operational parameters. The device includes an indication element for indicating the readiness for closing and a coupling element which interacts with the indication element. The operational parameters, for example, energy store empty or switchgear cell door open cause the indication element to pivot into the position not ready for closing and cause the coupling element to move into its disabled position. The indication element for indicating the readiness for closing and additional indication elements, which represent the position of the switching contacts and the state of the energy store, are adjacently arranged in an axial manner such that they can pivot and are provided with interacting drives in order to effect a forced drive of the indication element for indicating the readiness for closing when the position of the switching contacts or the state of the energy store does not enable or permit a closing of the power circuit breaker.
US 4301342 discloses an industrial circuit breaker having a spring-powered movable contact operating mechanism and a spring-powered charging mechanism, each having the facility of storing a charge rendering the circuit breaker capable of being closed, condition indicator apparatus includes a first indicator for indicating whether the breaker movable contacts are open or closed and a second indicator for indicating whether or not a charge is stored in either the operating mechanism or the charging mechanism.
US 4166989 discloses a circuit breaker is provided with a hook operating to hold the breaker movable contacts open against the bias of charged mechanism springs. The hook is selectively actuated by a closing solenoid to release the contacts for abrupt closure under the urgence of the

mechanism springs. An indicator is appropriately positioned under the joint control of the breaker mechanism and movable contacts to identify OFF, charged and ON breaker conditions and to, in turn, control an actuating lever for a switch operating in an external charged signaling and closing solenoid circuit.
In the existing arrangement of switches, for electrical indication of "Ready to Close" condition a micro switch (Normally Open or NO/Normally Closed or NC contacts) is used. After fulfillment of above mentioned conditions for "Ready to Close", a lever gets actuated and in-turn changeover of the micro switch occurs (NO contacts get closed and NC contacts get opened). This lever is actuated by the various interlocks (Sr. no. 1 to 6 mentioned above) directly.
The Spring Charge actuation is indirect type i.e. the lever is actuated by some intermediate linkages between lever and the actuator. The linkage in turn takes actuation from the charging shaft. This indirect type of actuation of the lever for spring charging has certain disadvantages. The linkage either gets actuated earlier or the actuation may get delayed from the exact time point at which spring gets charged. This is due to the time taken by the linkages for movement as well as the variations in manufacturing processes. Thus the actuation of lever taken from linkages may be false. Hence, the "Ready to Close" actuation in this type of designs is not exact or true type.
Thus, there is a need to overcome the problems of the prior art. Therefore, the present inventors have developed an improved actuation arrangement for use in circuit breakers. The purpose of this invention would be to have a direct type of actuation for the spring charging which will overcome the disadvantages of the existing design mentioned above. The direct type of actuation avoids any delay or early actuation of the lever. Hence the "READY TO CLOSE" actuation achieved in this type of design would be exact (true).Thus reliable operation of RTC would be achieved.
OBJECTS OF THE INVENTION
An object of the present invention is to overcome the problems/disadvantages of the prior art.
Another object of the present invention is to provide an improved actuation arrangement for use in circuit breakers

These and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Other features as well as the advantages of the invention will be clear from the following description. In the appended drawings:
Fig 1 illustrates a ratchet and pawl arrangement.
Fig 2 illustrates a pawl having an extended portion.
Fig 3 illustrates a teeth arrangement of Ratchet.
Figures 4, 5 , 6 and 7 illustrate a functioning of the Ready to Close arrangement.
SUMMARY OF THE INVENTION
According to one of the aspect of the present invention there is provided an improved actuation
arrangement for use in circuit breakers, said arrangement comprising
a side plate;
a micro switch fixed on said side plate , said switch comprising a roller means;
a lever means operatively connected with said roller means, said lever comprising
a screw means adapted to pivot with said lever means ;
a lever tail means ;
a ratchet arrangement operatively connected with a pawl arrangement, said ratchet arrangement
comprising
a ratchet means;
a charging shaft fixed substantially centrally at said ratchet means adapted to provide support to said
ratchet means;

wherein said ratchet means having a substantially circular modular profile comprising plurality of
tooth projecting outward and said teeth being formed on the outer side of said circular profile of said
ratchet means;
wherein said one of the teeth of said ratchet means having a increased height than the rest of the
teeth;
a pawl means placed in-between said lever means and said ratchet means , wherein said pawl means
comprising
a module means operatively connected with said teeth of said ratchet means and
a pawl tail means on the rear side of said module means adapted to get connected with said lever
means when
a spring means placed substantially behind said Pawl and said Ratchet arrangement to provide energy
for turning the circuit breaker ON.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to an improved actuation arrangement for use in circuit breakers. Air circuit breakers mechanism operates on stored energy principle. Since closing and opening time of breaker contacts is desired to be as minimum as possible, energy is stored in the mechanism by compressing a spring.
When it is required to close the breaker, whole energy is transferred to the contacts through linkages from the mechanism and hence breaker closes. Closing time solely depends on energy stored in the spring. Higher the energy stored lower the closing time. Charging of the spring is divided into strokes. So efforts for spring charging are reduced i.e. whole spring energy is given into parts. As strokes are given to the breaker, spring tries to come back. So locking is required at the end of each stroke.
According to one of the embodiment of the present invention there is provided an improved actuation arrangement for use in circuit breakers. The arrangement comprises a side plate; a micro switch fixed on the side plate where the switch comprises a roller means; a leaver means operatively connected with the roller means , a ratchet arrangement operatively connected with the pawl arrangement, a pawl means substantially placed in-between the lever means and the ratchet means and a spring

means placed behind the Pawl and the ratchet arrangement and is rotatably connected to the charging shaft.
The lever comprising a screw means adapted to pivot with the lever means and a lever tail means ,
The ratchet arrangement comprises a ratchet means ; a charging shaft substantially fixed at the ratchet means center adapted to provide support to the ratchet means . The ratchet means substantially having a circular modular profile where the ratchet means comprising plurality of tooth projecting outward and the tooth are formed on the outer side of the circular profile of the ratchet means . One of the teeth of the ratchet means is having a increased height than the rest of the tooth;
The pawl means comprises a module means operatively connected with the teeth of the ratchet means and a pawl tail means on the rear side of the module means adapted to get connected with the lever means.
The pawl means and racket mean adapted to provide actuation to the micro switch when the spring is fully charged.
The pluralities of tooth expect the tooth with greater height is of same height.
The lever peep is operatively connected with the pawl tail when the roller of micro switch is in pressed condition.
Plurality of tooth expect one of the tooth with greater height is in contact with the pawl means and the pawl tail goes substantially upward adapted to block the path of lever peep so as to keep the micro switch roller in pressed position .
The tooth with increased height when in contact with the pawl means is adapted for actuation of the micro switch means.
The tooth with increased height in contact with pawl means adapted to move pawl means substantially upward.

The tail of pawl moves down when the tooth with increased height in contact with pawl means and removes the hindrance with the lever peep means adapted to move up the lever means upward and the micro switch roller comes up and gets actuated.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and illustrate the best mode presently contemplated for carrying out the invention. Further functioning of the arrangement has been discussed below to describe the way the arrangement operates. However, such description should not be considered as any limitation of scope of the present unit. 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.
As shown in figure 1, Ratchet and pawl arrangement is provided to arrest each stroke. Ratchet is
fixed with the charging shaft (3). When a stroke is given to the charging shaft in anti clock wise
direction it rotates by an angle of 45° and spring is compressed to some extent. Because of return
spring force, charging shaft tries to rotate in clock wise direction but tooth no. 2 blocks it, i.e. normal
pawl and ratchet action. At the end of full charging, Tooth no. 8 is engaged with pawl, and spring is
fully charged.
A spring (not shown in fig.) placed behind the Pawl and Ratchet arrangement, to provide energy for
turning the circuit breaker ON.
Pawl and Ratchet are designed in such a way that apart from performing the primary function as
mentioned above, they can also be used to provide actuation to the micro switch when the spring is
fully charged.
As shown in figure 2, Pawl has an extended portion (8) on its right hand side which is used in this arrangement for actuation purpose.

As shown in figure 3, Tooth no. 8 of Ratchet (2) is having increased height (10) than other teeth (9).i.e. diameter of the circle drawn by following the path of rotation of Tooth no.8 is greater than the addendum circle.
Teeth no. 2, 3,....7 are having same height. Tooth no. 8 is having more height than other teeth. This extra height is used for the actuation of lever and hence micro switch. Micro switch (5) is fixed on the side plate and it is actuated by lever (6). This lever goes up only when all the conditions for making breaker ON are fulfilled. Spring charging is one of the conditions. As spring is charged completely, the lever goes up and it actuates the micro switch from which indication is taken.
The invention is related to actuation arrangement of the lever directly from the charging shaft. The Pawl and ratchet arrangement which is used for charging the spring through a charging handle has been modified in such a way that it will perform a dual function of charging as well as actuation for the lever.
Figure 4 shows the initial condition of the Ready to Close arrangement. Micro switch roller (11) is in pressed condition and the lever (6) is always pulled by a spring in upward direction and lever is pivoted by a screw (12). Lever tail always experiences a downward force. Extended part of pawl (8) restricts the lever tail from coming down and hence micro switch roller remains in pressed condition.
Part (7) mentioned in Fig. 1 is lever tail. Lever tail and Lever peep are the same. For charging of main spring, charging shaft (3) has to rotate in anti clock wise direction. As pawl rides over tooth no. 2 extended part of pawl (8) also moves with the pawl as pawl reaches the peak of tooth no. 2 ( refer Fig 5 ). Pawl (8) still blocks the path of lever tail (7). And hence still micro switch roller remains pressed. Tooth no. 2 to 7 are of same height (9) so phenomenon is same for tooth from 2 to 7 as shown in figures 5 and 6.
A spring means (not shown in fig.) placed behind the Pawl and Ratchet arrangement, to provide energy for turning the circuit breaker ON.
As shown in figure 7, as last tooth i.e. tooth no. 8 comes , which is having increased height than other ( 10). On this tooth, pawl moves up by slightly more distance than on other teeth and hence rear side of pawl (8) comes down, and it removes the hindrance to the lever peep (7). As the lever goes up by

its upward spring force, Micro switch roller comes up and micro switch is actuated as shown in figure 7.
ADVANTAGES OF THE INVENTION
1. Direct actuation
2. No extra component required (modification in existing ratchet is done to perform dual function of RTC actuator).
3. Reliable operation (no chances of false indication )
4. Wide range of variation in manufacturing processes can be absorbed
Constructional elements
1. Side plate
2. Ratchet
3. Charging shaft
4. Pawl
5. Micro switch
6. Lever
7. Lever tail ( peep)
8. Extended part of pawl
9. Normal ratchet tooth
10. Increased ratchet tooth
11. Micro switch roller
12. Lever pivoting screw.

WE CLAIM
1. An improved actuation arrangement for use in circuit breakers, said arrangement
comprising: (i) a side plate;
(ii) a micro switch fixed on said side plate , said switch comprising a roller
means; (iii) a lever means operatively connected with said roller means, said lever
comprising
a screw means adapted to pivot with said lever means ;
a lever tail menans; (iv) a ratchet arrangement operatively connected with a pawl arrangement, said
ratchet arrangement comprising
a ratchet means;
a charging shaft fixed substantially centrally at said ratchet means adapted to
provide support to said ratchet means;
vvherein said ratchet means having a substantially circular modular profile
comprising plurality of tooth projecting outward and said teeth being formed
on the outer side of said circular profile of said ratchet means;
said one of the teeth of said ratchet means is having a increased height than
the rest of the teeth; (v) a pawl means placed in-between said lever means and said ratchet means ,
wherein said pawl means comprising
a module means operatively connected with said teeth of said ratchet means
and
a pawl tail means on the rear side of said module means adapted to get
connected with said lever means and

(vi) a spring means placed behind said Pawl and said ratchet arrangement and is rotatably connected to said charging shaft.
2. Arrangement as claimed in claim 1 wherein said pawl means in alliance with said ratchet mean adapted to provide actuation to said micro switch when said spring is fully charged.
3. Arrangement as claimed in claim 1 wherein said plurality of teeth are of same height except the tooth with greater height.
4. Arrangement as claimed in claim 1 wherein said lever peep is operatively connected with said pawl tail when said roller of micro switch is in pressed condition.
5. Arrangement as claimed in claim 1 wherein said plurality of tooth expect one of the said tooth with greater height is in contact with said pawl means such that said pawl tail goes substantially upward adapted to block the path of lever peep so as to keep the micro switch roller in pressed position .
6. Arrangement as claimed in claim 1 wherein said tooth with increased height when in contact with said pawl means is adapted for actuation of said micro switch means.
7. Arrangement as claimed in claim 6 wherein said tooth with increased height in contact with pawl means adapted to move pawl means substantially upward.
8. Arrangement as claimed in claim 7 wherein said tail of pawl moves down when said tooth with increased height in contact with pawl means and removes the hindrance with said lever peep means adapted to move up the lever means upward and said micro switch roller comes up and gets actuated.

9. An improved actuation arrangement for use in circuit breakers as herein substantially described and illustrated with the accompanying drawings.