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 INTRINSIC ROTARY
OPERATED MECHANISM FOR CIRCUIT BREAKER
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 circuit breaker. More particularly, the invention relates to an improved rotary operating mechanism for use in circuit breakers. The invention also relates to a circuit breaker comprising the rotary mechanism.
BACKGROUND AND THE PRIOR ART
Circuit Breaker is a mechanical switching device, capable of making (i.e. switching ON), carrying and breaking (i.e. switching OFF) current under normal circuit conditions and more specifically breaking current (Tripping) during abnormal circuit conditions such as short-circuit. Quit often, the short circuit current is sensed automatically and the signal is given to the mechanism as a TRIP command which leads to opening of the contacts by means of mechanism. However, during normal ON to OFF and OFF to ON operation, input to mechanism is given through the rotation of knob by manual means. The rotation of handle leads to storing potential energy (spring charging) in the spring member. At a specified instance, the potential energy of spring is released in the form of Kinetic energy through Mechanical Linkages leading to the rotation of the contacts at high velocity. Circuit breaker mechanisms use dead-centre based Extension spring arrangements.
Conventionally, to operate a Molded Case Circuit Breaker (MCCB), pull and push type of force needs to be applied on the Breaker knob. Whereas, to be adaptable on the panel-mounting conventionally, the Circuit Breaker should be rotary operated; and instead of pull and push type of force on the knob, a torque is applied on the Breaker Handle to operate the same. So to fulfill the same requirement, an additional accessory is attached to the Circuit Breaker and instead of pull and push type force, a torque is applied on the Handle to operate the Breaker. It has been found that the use of additional accessory in the circuit

breaker makes the system bulky and increases the overall cost of the circuit
breaker system.
US6518526 discloses a handle-operating mechanism for a circuit breaker including a rotary operating handle for opening and closing a main-circuit contact of a circuit breaker, a rotating gear operably connected to the operating handle and having a first engaging device, and a contact opening-and-closing mechanism having a toggle gear meshing with the rotating gear. A clutch gear is connected to the operating handle to be interposed between the operating handle and the rotating gear, and has a second engaging device. An idle stroke is formed such that when the circuit breaker is turned on, the operating handle runs idly after rotation of the operating handle has been started and before the second engaging device engages the first engaging device to drive the rotating gear for actuating the toggle gear.
US 6194983B1 discloses a circuit interrupter handle mechanism disposed on the face of a molded case circuit breaker. The handle mechanism has a rotary handle, which may be rotated through approximately 90.degree. of rotation from a disposition of circuit interrupter conduction to a disposition of circuit interrupter non-conduction. The handle is not centered over the linear handle of the circuit interrupter per say, but rather is disposed in the upper left hand corner, so that a larger lever arm can be utilized. Furthermore, the larger lever has a handle opening into which the hasp of a lock may be placed to lock the circuit breaker in the open state for servicing and the like. Because of the length of the handle more hasps can be disposed therein than if the handle was disposed exactly, in the center of the circuit breaker case. Lastly, the disposition of the circuit breaker rotary handle provides an indication of the conduction status of the molded case circuit breaker. If the handle is in a generally horizontal position, i.e., straight across the front of the circuit interrupter, that is an indication that the contacts of the circuit interrupter are open and that current therefore is blocked. If on the other hand the handle is 90.degree. displaced, in a rotational manner, to be parallel with the long

longitudinal axis of the circuit interrupter, then an indication is given that the circuit interrupter contacts are closed and current is being conducted.
US5302925 discloses a molded case circuit breaker rotary handle operator allows the circuit breaker handle to be locked when the circuit breaker contacts are open. The handle is prevented from being locked in position when the circuit breaker contacts are welded in their closed condition.
US3697714 discloses a handle mechanism for operating a molded case circuit breaker secured to the rear wall of an enclosure is mounted separate from the enclosure cover and extends through a cover opening to be operable from outside the enclosure when the cover is closed. The mechanism is constructed so as to be readily adapted for use with enclosure covers that are hinged at either side of the enclosure.
US5219070 discloses a rotary handle operator for a circuit breaker with a linearly movable handle has a housing which is mounted over the circuit breaker handle. A slide carrying a rack engages the circuit breaker handle and is slidable within a chamber in the housing. The rack engages a pinion gear sector mounted on a rotatable shaft which extends through a cover on the housing. A rotating handle mounted on the shaft is rotated to linearly operate the circuit breaker handle or is positioned thereby when the circuit breaker trips. The handle may be locked in the off position by inserting the shackle of a lock through an aperture in a lever arm on the rotating handle to urge a pin on a spring biased locking piece within the handle lever into an aperture in the housing cover, or the shackles of several locks may engage a slot in a shroud surrounding the rotating handle to interfere with rotation of the handle out of the off position. An interlock for the door of a cabinet in which the circuit breaker may be mounted is incorporated into the rotary door operator.

US4528531 discloses a molded case circuit breaker including a highly integrated operating mechanism having an over-center toggle mechanism for opening and closing a pair of electrical contacts and a trip mechanism for responding to overload and short circuit or fault current conditions to separate the pair of electrical contacts. A generally flat, intermediate latch plate includes an upper latch surface for latching with a movable cradle of the over-center toggle mechanism and a lower latch surface for latching with a trip bar of the trip mechanism and a pair of outwardly projecting pivot arms disposed between the upper and lower latch surfaces. The over-center toggle mechanism includes a pair of upper toggle links and a pair of lower toggle links interconnected by a toggle spring pin. To increase the speed of separation of the first and second electrical contacts during a trip operation, the cradle is physically configured to engage and upwardly propel the toggle spring pin and, also, the upper toggle links have projections for physically contacting a rigid stop.
US6479774B1 discloses a circuit breaker operating mechanism that comprises of a movable handle yoke, a mechanism spring extending in tension from the handle yoke to a pin, and a lower link extending from the pin to a crank operably connected to a contact arm bearing a movable contact. The crank is positionable in open and closed positions, being in an open position when the movable contact is separated from an associated fixed contact and being in a closed position when the movable contact is mated to said associated fixed contact. The circuit breaker further comprises an interface formed on said crank and a blocking prop having a first surface that engages said interface, the first surface preventing the crank from rotating towards the closed position.
US6590172B1 discloses a circuit breaker wherein the circuit breaker comprises a contact arm movable between a closed position, an open position and a blown open position wherein the contact arm is disposed in the circuit breaker. A bumper is disposed to contact the contact arm when the contact arm is in the blown open position. In addition, a stop member is disposed to be in contact with a linkage

assembly so as to create a gap between the bumper and the contact arm when the contact arm is disposed in the open position.
Many prior art documents as stated hereinabove have been studied and it has been found that the knob in a circuit breaker involves push -pull type of forces. In order for these Breakers to be operated by a Rotary Handle, an additional accessory called a Rotary Operated Mechanism is required, which needs to be mounted on top of the Knob. The inventors have studied and found that the Linear Knob-operated Breakers require higher operating force from the user, when compared to a Rotary Handle-operated Breaker. Rotary operation gives more ergonomic comfort to the user, when compared to a Knob-operated one. For the conversion of rotary to linear motion using a ROM, additional components and additional space are required. Such requirement of additional space increases the size of the circuit breaker.
The inventors have found that a unique design and a combination of a gear means and fork means if provided give rise to a rotary handle operating mechanism for circuit breakers in the same limited conventional space and the same number of components without adding any extra accessory to the conventional circuit breaker which would provide better control and lesser effort to the operator. It is to be understood that the results achieved by such design can also be achieved by technical equivalents of gear means without departing from the true spirit of the present invention.
OBJECTS OF THE INVENTION
One object of the present invention is to overcome the drawbacks/disadvantages
of the prior art.
A basic object of the present invention is to provide an improved rotary operated mechanism for use in circuit breakers.

Another object of the present invention is to provide a circuit breaker comprising the rotary mechanism within its boundaries.
Another object of the present invention is to eliminate the need to use an external rotary operating mechanism which are mounted on breaker knobs.
These and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
According to an aspect of the present invention there is provided an intrinsic rotary operating mechanism for use in circuit breakers, said mechanism
comprising:
a rotary handle means (4e); and
bevel pinion assembly (4b) mounted on side plate means (3a) means of a
conventional mechanism module (3),
said assembly (4b) comprises a bevel pinion means (4d) and bevel gear means
(4a), said bevel pinion means (4d) being assembled onto a bearing plate means
(4c) providing bearing for the bevel pinion means (4d) and said bevel pinion

means being coupled to said rotary handle means (4e) such that in operation said
bevel Pinion means (4d) drives the bevel Gear (4a) means; and
said bevel gear means (4a) being coupled to fork link means (3e) of a
conventional mechanism module (3) such that in operation said rotary handle
means (4e) drives the fork link means (3e) of a mechanism module (3);
wherein the said intrinsicrotary operated mechanism can be converted to an linear
knob operated mechanism by a minimum change in components, i.e., by
disassembling the Bevel Gear Means (4a) and the Bevel Pinion Assembly (4b)
from the Mechanism Module (3)and attaching the Linear Knob (3g) means to the
same.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
So that those having ordinary skill in the art will more readily understand how to construct an improved rotary operating mechanism for use in circuit breakers in accordance with the present disclosure, exemplary embodiments are described in details herein below with reference the accompanying drawings wherein:
Fig. 1 illustrates a Sectional view of the Circuit Breaker in ON condition.
Fig. 2 illustrates anSide view of the Circuit Breaker in ON condition. Fig.3 illustrates a Sectional view of the Circuit Breaker in OFF condition. Fig. 4 illustrates an Side view of the Circuit Breaker in OFF condition. Fig. 5 illustrates anSectional view of Mechanism in TRIP condition. Fig. 6 illustrates anSide view of Mechanism in TRIP condition.

Fig. 7 illustrates an isometric Exploded view of the intrinsic rotary operated mechanism in OFF condition.
Fig. 8 illustrates an Isometric Exploded view of the conventional linear knob
operated mechanism in OFF condition.
Fig. 9 illustrates an Isometric view of the intrinsic rotary operated mechanism in
OFF condition.
Fig. 10 Illustrates an isometric view of the Bevel Pinion Assembly.
Fig. 11 Illustrates an exploded isometric view of the Bevel Pinion Assembly
Fig. 12 Illustrates an isometric view of Bevel Gear and Internal Accessory.
BRIEF 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 mechanism has been discussed below to describe the way the mechanism 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.
Elements and Construction
1: Rotor: It is the part which houses the Moving-contact assembly

2: Moving Contact: It is the moving part of the current carrying circuit.
3: Mechanism module: It consists of various linkages. It is a 4 bar mechanism.
3a: Side plate: It is a part of mechanism module. It guides the handle gear
3 b: Lower Link: It is connected between upper link and rotor.
3c: Upper Link: It decides position of dead centre during ON-OFF and OFF-ON operation. One end of it is fixed during ON-OFF and OFF-ON operation and moving during TRIP operation.
3d: Latch Link - It is a link to which upper link is connected. It moves during ON to TRIP condition.
3e: Fork link: It is a link to which mechanism springs are connected.
3f: Spring Pin -. Is it inserted in the fork link to which springs are getting connected.
3g: Linear Knob - It is connected to the fork link. User applies the force to knob to operate the circuit breaker.
3h: Floating pin: It is connected to the upper link. One end of the spring is connected to it.
3i: Springs: springs are energy storing elements. One end of which is connected to spring pin and another end is to floating pin.
3j: Latch Bracket: It locks the Latch Link during ON-OFF & OFF-ON operation and unlocks during ON-TRIP operation.

3k: Trip Plate : It locks the Latch Bracket during ON-OFF & OFF-ON operation and unlocks during ON-TRIP operation. It is a part to which TRIP signal is
actuated.
31: Reset Pin: It is connected to the Latch Link. Mechanism get reset during TRIP to RESET operation by fork link via reset pin.
4a: Bevel Gear: It is connected to the fork link and it engages with the Bevel
Pinion.
4a(l): Accessory Reset Feature : It is a feature on the Bevel Gear (4a) which engages with the internal accessories (6) to reset them during the TRIP to RESET operation of the mechanism.
4b: Bevel Pinion Assembly : It consists of the Bearing Plate, Bevel Pinion and a pinion Plate. It is mounted onto the side plate, such that the Bevel Pinion engages the Bevel Gear.
4c: Bearing Plate : It is the plate on which the Bevel Pinion rotates and it is mounted onto the side plates.
4c(l): Pinion Slot: it is a slot in the bearing plate (4c) to accommodate the teeth of the Bevel Pinion such that the end surfaces also act as stoppers for the Bevel Pinion (4c) in ON and RESET operations.
4d: Bevel Pinion : It is directly engaged with the rotary handle and it drives the
mechanism.
4d(1): Hub Slot: It is a slot on the hub of the Bevel Pinion (4d) to accommodate
the bearing plate (4c)

4d(2): Spring Slot: It is a slot on the hub of the Bevel Pinion (4d) to accommodate the spring (3i) during operation.
4e: Rotary Handle: It is manually rotated to achieve various positions of the circuit
breaker.
5: Fixed Contact: It is the fixed part of the current carrying unit.
6: Internal Accessories : Its is the component that receives the TRIP signal from the sensing unit and actuates the mechanism to TRIP. It also needs to be reset during the TRIP-RESET operation.
Detailed description of working of the invention
The present invention relates to a Circuit Breaker which is a mechanical switching device, capable of making (i.e. switching ON), carrying and breaking (i.e. switching OFF) current under normal circuit conditions and more specifically breaking current (Tripping) during abnormal circuit conditions such as short-circuit. Quite often, the short circuit current is sensed automatically and the signal is given to the mechanism as a TRIP command which leads to opening of the contacts by means of mechanism.
The conventionalLinear knob operated circuit breaker mechanism (Figure 8)
comprises:
An operating knob (3g) means fixed onto a mechanism module (3) which comprises a fork link (3e) means which drives a dead-centre based mechanism consisting of a plurality of upper link (3c) means, lower link (3b) means, and at least one spring (3i) mounted between a spring pin (3f) means and a floating pin (3h) means; the upper spring hinge located on the fork link (3e) means and the

lower spring hinged on the floating point located on the upper link (3c) means; The said upper link (3c) means and said lower link (3b) means being pivotally connected to each other and said lower link (3b) means being operatively connected between said upper link (3c) means and said rotor (2) means; The other end of said upper link (3c) means is pivoted on a latch link means (3d) which is operatively mounted on a plurality of side plate (3a) means. Also attached to said latch link (3d) means is a reset pin (3m) which engages a cam profile on the fork link means during TRIP-RESET operation.
In a conventional linear knob operated mechanism (Fig8), during normal ON-OFF and OFF-ON operation, input to mechanism is given through the Linear knob (3g) means by manual operation.The push-pull of the linear knob (3g) means leads to storing potential energy (spring charging) in the spring(3i) means while restricting the moving contact (2) movement during the charging operation. At a specified instance the potential energy of spring is released in form of Kinetic energy through Mechanical Linkages leading rotation of the moving contact (2) at high velocity. Circuit breaker mechanisms use dead centre based Extension spring arrangements.
In the present invention, the mechanism is operated by a Rotary handle (4e) means instead of a Linear knob (3g) means; hence substituting the conventional linear motion (push-pull) with a rotary motion (torque).
The intrinsic rotary operated mechanism comprises:
A Rotary handle (4e) means is directly coupled with the Bevel Pinion (4d) means which drives the Bevel Gear (4a) means. The Bevel Pinion (4d) means is part of the Bevel Pinion Assembly (4b) which comprises The Bevel Pinion (4d) means assembled onto a bearing plate (4c) means which provides the bearing for the Bevel Pinion (4d) means. The Bevel Pinion Assembly (4b) is directly mounted on the side plate (3a) means of a conventional mechanism module (3). The Bevel Gear (4a) means is directly coupled to the Fork link (3e) means of a conventional

mechanism module (3).Hence the rotary handle means (4e) drives the Fork link (3e) means of a mechanism module (3) through a pair of Bevel Gears.
Figure 2 shows the side view of the Mechanism in ON position and figure 1 shows the sectional view of the same. When Rotary Handle (4e) means is rotated by the user, through the Bevel Gears it rotates the Fork link (3e) means in the clockwise direction. Springs (3i) connected between spring pin (3f), which is mounted on the fork link (3e) means, and floating pin (3h) which is mounted on the upper link (3c) means, get deflected up to dead centre condition and after the dead centre the stored energy in the spring is converted in to kinetic energy which is used to rotate the moving contact (4) from ON to OFF position through upper link (3c) and lower link (3b).
Figure 4 shows the side view of the Mechanism in OFF position and figure 3 shows the sectional view of the same. When Rotary Handle (4e) means is rotated by the user, through the Bevel Gears it rotates the Fork link (3e) means in the clockwise direction. Springs (3i) connected between spring pin (3f), which is mounted on the fork link (3e) means, and floating pin (3h) which is mounted on the upper link (3c) means,get deflected up to dead centre condition and after the dead centre the stored energy in the spring is converted in to kinetic energy which is used to rotate the moving contact (4) from OFF to ON position through upper link (3c) and lower link (3b).
Figure 6 shows the side view of the Mechanism which is in TRIP position and figure 5 shows the sectional view of the same. When actuation signal is given to the trip plate (3k) in ON condition, it rotates and unlocks the latch bracket (3j) which results in enabling the rotation of latch link (3d). At ON position spring is having stored potential energy which enables the latch link (3d) rotation. Upper link (3c) and lower link (3b) are connected to the latch link (3d) so as rotation of latch link (3d) results in rotation of rotor (2). Moving contact (4) connected to the rotor (2) also rotates and breaker gets disconnected and now in TRIP

position.During TRIP to RESET operation user rotates the rotary handle (4e). At TRIP position fork link (3e) touches with the reset pin (31) which is inserted in the latch link (3d). So when force is applied on knob (3g), latch link (3d) is rotated which enables bringing the upper link (3c) & lower link (3b) from TRIP to RESET position.
Figure 8 shows the isometric view of a conventional linear knob operated circuit breaker mechanism and figure 7 shows the isometric view of an intrinsic rotary handle operated mechanism. In both the figures the components outside the mechanism module (3) are in exploded view. Thus, by disassembling the Bevel Gear Means (4a) and the Bevel Pinion Assembly (4b) from the Mechanism Module (3) and attaching the Linear Knob (3g) means to the same, we can convert an intrinsic rotary operated mechanism into a linear knob operated mechanism.
Figure 9 shows the isometric view of the intrinsic rotary operated mechanism in OFF condition.
Figure 10 shows an isometric view of the Bevel Pinion Assembly (4b) and figure 11 shows the exploded view of the same. The Bevel Pinion (4d) is shown to have a slot on the hub of the gear called the Hub Slot (4d(l)) such that the hub thickness is less than the width of the gear face. The Bearing plate is accommodated in that space for compactness of the mechanism. The Bevel Pinion (4d) is shown to have another slot on the hub of the gear called the Spring Slot (4d(2)) such that the spring (3i) is accommodated in the slot during the operations. The Bearing plate (4c) is shown to have a slot calledPinion Slot (4c(l)) which the gear teeth are accommodated such that the ends of the slot act as a stopper for the Bevel Pinion in ON and RESET conditions of the mechanism.
Figure 12 shows the Bevel Gear interact with an internal accessory like Solenoid release, Under Voltage release or Shunt release. After the internal accessories (6) trips the circuit breaker it needs to be reset by the mechanism. The resetting of the

internal accessories (6) is carried out simultaneously with the mechanism RESET operation. This function can be carried out by a feature on the Bevel Gear (4a) means called the Accessory Reset Feature (4a(l)) which engages the internal accessories (6) such that during the RESET operation of the mechanism the internal accessories (6) also resets.
Advantages:
♦ The Rotary operation is directly integrated into the Mechanism of the Breaker.
♦ Minimal additional space is required to enable the rotary to linear conversion of motion for operating the Breaker.
♦ Fewer efforts are required compared to conventional pull-push type knob-operated Circuit Breakers.
♦ Economically more comfortable to operate the circuit breaker.
♦ Better control on the ON-OFF, OFF-ON & TRIP-RESET operation.
♦ Eliminates the need for an external Rotary Operating Mechanism (ROM) to do the same job, thereby saving space and material.
♦ More efficient than a ROM because of direct transmission of forces from Handle to Fork.

WE CLAIM
1. An intrinsic rotary operated mechanism for use in circuit breakers, said
mechanism comprising :
a rotary handle means (4e); and
bevel pinion assembly (4b) mounted on side plate means (3a) means of a
conventional mechanism module (3),
said assembly (4b) comprises a bevel pinion means (4d) and bevel gear
means (4a), said bevel pinion means (4d) being assembled onto a bearing
plate means (4c) providing bearing for the bevel pinion means (4d) and
said bevel pinion means being coupled to said rotary handle means (4e)
such that in operation said bevel Pinion means (4d) drives the bevel Gear
(4a) means; and
said bevel gear means (4a) being coupled to fork link means (3e) of a
conventional mechanism module (3) such that in operation said rotary
handle means (4e) drives the fork link means (3e) of a mechanism module
(3);
wherein the said intrinsicrotary operated mechanism can be converted to an linear knob operated mechanism by a minimum change in components, i.e., by disassembling the Bevel Gear Means (4a) and the Bevel Pinion Assembly (4b) from the Mechanism Module (3)and attaching the Linear Knob (3g) means to the same.
2. Mechanism as claimed in claim 1 wherein said fork link means (3e) of the mechanism module (3) comprises provision for attachment of Bevel Gear (4 a) means.
3. Mechanism as claimed in claim 1 wherein said side plate (3a) means of the mechanism module (3) comprises provision for attachment of Bevel Pinion Assembly (4b).

4. Mechanism as claimed in claim 1 wherein said bearing plate means (4c) comprises provision for attachment of Bevel Pinion (4d) means.
5. Mechanism as claimed in claim 1 wherein said bevel pinion means (4d) comprises a Hub Slot (4d(I)) for accommodation of Bearing plate means for compactness of Bevel Pinion Assembly.
6. Mechanism as claimed in claim 1 wherein said bearing plate means (4c) comprises a pinion slot (4c(l)) which provides the stopper for the Bevel Pinion (4d) means in ON and RESET positions.
7. Mechanism as claimed in claim 1 wherein said bevel gear means (4a) comprises a Accessory Reset Feature (4a(l)) for resetting of internal accessories.
8. Mechanism as claimed in claim 1 wherein said bevel pinion means (4d) comprising another slot on the hub of the gear called the Spring Slot (4d(2)) such that the spring (3i) is accommodated in the slot during the
operations.
9. An intrinsic rotary operated mechanism for use in circuit breakers as
herein described and illustrated with reference to accompanying drawings.