FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION (See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"An Electrical Charging Device For a Switch-Gear Mechanism"
2. APPLICANT:
(a) NAME: Larsen & Toubro Limited
(b) NATIONALITY: Indian Company registered under the
provisions of the Companies Act-1956.
(c) ADDRESS: LARSEN & TOUBRO LIMITED,
L&T House, Ballard Estate, P. O. Box: 278, Mumbai 400 001, India
3. PREAMBLE TO THE DESCRIPTION:
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

An Electrical Charging Device For a Switch-Gear Mechanism
FIELD OF INVENTION
The present invention relates to the field of an electrical charging device, more particularly, the present disclosure relates to an electrical charging device for a switch gear mechanism.
BACKGROUND OF THE INVENTION
In an electric power system, switchgear is used for protection against electrical faults such as such as short-circuit, overload, and earth faults. The switch gear is a combination of electrical disconnect switches, fuses or circuit breakers used to control protect and isolate electrical equipment. The switchgear is used both to de-energize equipment to allow work to be done and to clear faults downstream. The efficient operation of the switchgear is important for ensuring proper, efficient operation and reliability of the electricity supply system.
Generally, electrical faults such as short circuiting, overloading and earth faults in a power distribution network of a power distribution system may cause irreparable damage to the power distribution system. Further, such electrical faults may also cause fire hazards. The switchgear is a safety system that utilizes a combination of electrical dis-connect switches, fuses and circuit breakers for ensuring safety. A circuit breaker is an automatically operated electrical switch that cuts off electrical flow to the remaining power distribution network or isolates the faulty power distribution network in an event of a possible electrical fault, such as short-circuit, overload, and earth faults, thereby protecting the power distribution system against damages caused by short-circuiting or overloading. The circuit breaker is generally an electro-magnetic device that localizes the electrical fault by isolating the faulty power distribution network, thereby preventing damage to the entire power distribution system. More specifically, a trip unit detects a fault conditions based on current and voltage measurements and issues a trip command to the circuit breaker.

The circuit breaker in-turn, by interrupting the electrical continuity immediately discontinues electrical flow to the remaining power distribution network, thereby isolating the faulty power distribution network and protecting the remaining power distribution network against any further damage.
As the switch gear mechanism is an electrical safety system that includes a plurality of circuit breakers, fuses and other electrical disconnect switches that enables the switch gear mechanism to redundantly prevent any damage to the power distribution system due to electrical faults such as such as short-circuit, overload, and earth faults. As the circuit breaker trips in case of an electrical fault, the power supply to the trip unit of the circuit breaker as well as other elements of the switch gear mechanism is disrupted. The circuit breaker is generally powered through a current transformer. Further, as the circuit breaker trips, there is no flow of electrical current to the circuit breaker and no power is available for operating the elements of the conventional switch gear mechanism. The conventional switchgear mechanism utilizes a charging system that uses gearboxes using worm-worm wheel gears for speed reduction. Further, the charging system for the conventional switch gear mechanism fails to provide provision for automatic electrical and mechanical cut-off. As the conventional charging system fail to provide automatic mechanical cut-off, the assembly of the switch gear mechanism and the charging system is subjected to high intensity jerks and vibrations that are detrimental for the efficient operation of the switch gear mechanism and the charging system. Further, the worm wheels used in the charging system for the conventional switch gear mechanism are expensive, less reliable, are prone to frequent failure, require regular maintenance and have low wear life.
Accordingly, there is a need for a switch gear assembly that eliminates the drawbacks associated with conventional switch gear mechanism utilizing worm wheels in charging system thereof. Further, there is a need for a switch gear assembly that uses charging system that has provision for automatic mechanical cutoff and electrical cutoff. Further, there is a need for a charging system for a switch gear assembly that is simple in construction, convenient to use and

inexpensive. Still further, there is a need for a switch gear assembly that utilizes an alternate and readily available source of power or that can be manually powered for charging and operating the elements of the switch gear mechanism. Furthermore, there is a need for a charging system for a switch gear mechanism that is reliable and ensures safety of the electrical distribution system. Still further, there is a need for a charging system for a switch gear assembly that is sturdy, that does not fail and has longer service life. Further, there is a need for a charging system for a switch gear assembly that may be easily retrofitted and used with any of the conventionally known electrical distribution systems.
OBJECTS OF THE INVENTION
Some of the objects of the present invention are described herein below:
It is an object of the present invention to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present invention is to eliminate the drawbacks associated with conventional switch gear mechanisms using charging systems that uses gearboxes having worm-worm wheel gears for speed reduction.
Another object of the present invention is to provide a charging system for switch gear mechanism that has provision for automatic mechanical cutoff and electrical cutoff.
Yet another object of the present invention is to provide a charging system for a switch gear assembly that is simple in construction and convenient to use.
Still another object of the present invention is to provide a charging system for a switch gear assembly that uses an alternate and readily available source of power or that can be manually powered for charging and operating the elements of the switch gear assembly.

Yet another object of the present invention is to provide a charging system for a switch gear assembly that is reliable and ensures safety of the electrical distribution system.
Still another object of the present invention is to provide a charging system for a switch gear assembly that is sturdy, that does not fail and has longer service life.
Another object of the present invention is to provide a charging system for a switch gear assembly that requires less maintenance.
Still another object of the present invention is to provide a charging system for a switch gear assembly that is inexpensive.
Still another object of the present invention is to provide a charging system for a switch gear assembly that may be easily retrofitted and used with any of the conventionally known switch gear assembly and electrical distribution system.
Yet another object of the present invention is to provide a charging system for a switch gear assembly that ensures proper maintenance and safety of the power distribution system.
SUMMARY OF THE INVENTION
An electrical charging system for switch gear mechanism is disclosed in accordance with an embodiment of the present disclosure. The electrical charging system for switch gear mechanism includes a charger assembly and a mechanism assembly. The charger assembly includes a gearbox assembly and a motor assembly. The gearbox assembly includes a rear housing assembly, a front housing assembly, a top plate assembly and a primary shaft assembly. The rear housing assembly includes a pivot shaft for electrical cutoff, a roller cam for cut-off assembly, an electrical cut-

off lever mounted on the pivot shaft for electrical cut-off and a plurality of limit switches. The electrical cut-off lever has a first end and a second end, wherein the first end of the electrical cut-off lever is actuated by rotation of the roller cam of the cut-off assembly to facilitate rotation of the electrical cut-off lever over the pivot shaft for electrical cut-off. The plurality of limit switches are actuated by a second end of the electrical cut-off lever as the second end of electrical cut-off lever presses against the limit switches due to rotation of the electrical cut-off lever. The primary shaft assembly includes a gear arrangement, a primary shaft, a link, a ratchet and a pawl. The gear arrangement derives power from a pinion. The primary shaft is functionally coupled to the gear arrangement and is driven by gears of the gear arrangement. The link is mounted on the primary shaft and rotates along with the primary shaft. The pawl is pivotably mounted on the link and has a cam disposed thereon, wherein the pawl is urged against teeth of said ratchet by a spring element for facilitating engagement between the pawl and the teeth of said ratchet, the cam engages with the roller cam of the cut-off assembly to cause actuation thereof. The motor assembly includes a motor, a motor shaft and a pinion. The motor shaft is driven by the motor and the pinion is mounted on the motor shaft, the pinion drives the gear arrangement of the primary shaft assembly. The mechanism assembly includes a charging shaft and a charging shaft cam. The charging shaft cam is mounted on the charging shaft and is provided with male protrusions configured thereon.
Typically, the gear arrangement includes a secondary pinion, a bevel gear and a tertiary gear.
Generally, the motor of the motor assembly is a DC motor.
Particularly, rear housing and a front housing of the rear housing assembly and the front housing assembly are made of metal sheets having a plurality of legs bent from the same plane of the sheet.

Typically, the pawl and the ratchet are detactably mounted on separate bodies
placed rotatably along a common axis.
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 illustrates an exploded view of a charging shaft assembly disassembled from a rear housing assembly of a charging system in accordance with an embodiment of the present invention;
Figure 2 illustrates an electrical cut-off lever of the charging shaft assembly of Figure 1 in a pre-electrical cut-off position, wherein the electrical cut-off lever is maintained away from limit switches;
Figure 3 illustrates the electrical cut-off lever of the charging shaft assembly of Figure 1 in a post-electrical cut-off position, wherein the electrical cut-off lever is in contact with the limit switches for facilitating actuation thereof;
Figure 4 illustrates an assembled view of a primary shaft assembly, wherein a link is mounted on a primary shaft, a pawl is mounted on the link and is disengaged from a roller cam for cut-off assembly, i.e. the roller cam for cut-off assembly and the pawl are in a pre-delatch configuration;
Figure 5 illustrates an exploded view of the primary shaft assembly illustrating the primary shaft, the pawl, the link, the roller cam for cut-off assembly of Figure 4;
Figure 6 illustrates a front view of the primary shaft assembly with pawl disengaged from the roller cam for cut-off assembly, i.e. the roller cam for cut-off assembly and the pawl are in a pre-delatch configuration;
Figure 7 illustrates a front view of the primary shaft assembly with the pawl engaging with the roller cam for cut-off assembly, i.e. the roller cam for cut-off assembly and the pawl are in a de-latching configuration;

Figure 8 illustrates the exploded view of the primary shaft assembly of Figure 7;
Figure 9 illustrates an exploded view of a motor assembly;
Figure 10 illustrates an assembled view of the motor assembly of Figure 9;
Figure 11 illustrates an assembled view of the rear housing assembly;
Figure 12 illustrates an exploded view of the rear housing assembly of Figure 11;
Figure 13 illustrates an isometric view of a rear housing of the rear housing assembly of Figure 11 and Figure 12;
Figure 14 illustrates an isometric view of a bush used in the rear housing assembly of Figure 11 and Figure 12;
Figure 15 illustrates an isometric view of a roller cam for cut-off assembly of the rear housing assembly of Figure 11 and Figure 12;
Figure 16 illustrates an isometric view of a pivot shaft for electrical cut-off of the rear housing assembly of the rear housing assembly of Figure 11 and Figure 12;
Figure 17 illustrates an isometric view of an electrical cut-off lever of the rear housing assembly of Figure 11 and Figure 12;
Figure 18 illustrates an isometric view of limiting switches of the rear housing assembly of Figure 11 and Figure 12;
Figure 19 illustrates an isometric view of a bush for a front housing of a front housing assembly;

Figure 20 illustrates an isometric view of the front housing of the front housing assembly;
Figure 21 illustrates an assembled view of a top plate assembly;
Figure 22 illustrates an exploded view of the top plate assembly of Figure 21;
Figure 23 illustrates an isometric view of a shaft of the top plate assembly of Figure 21 and Figure 22;
Figure 24 illustrates an isometric view of a primary helical gear of the top plate assembly of Figure 21 and Figure 22;
Figure 25 illustrates an isometric view of a bush for primary helical gear of the top plate assembly of Figure 21 and Figure 22;
Figure 26 illustrates an isometric view of a primary bevel gear of the top plate assembly of Figure 21 and Figure 22;
Figure 27 illustrates an isometric view of a bush for primary bevel pinion of the top plate assembly of Figure 21 and Figure 22;
Figure 28 illustrates an isometric view of a top plate of the top plate assembly of Figure 21 and Figure 22;
Figure 29 illustrates an assembled view of the primary shaft assembly;
Figure 30 illustrates an exploded view of the primary shaft assembly of Figure 29;
Figure 31 illustrates an isometric view of a primary shaft of the primary shaft assembly of Figure 29 and Figure 30;

Figure 32 illustrates a bevel gear of a gear arrangement of the primary shaft assembly of Figure 29 and Figure 30;
Figure 33 illustrates a secondary pinion of the gear arrangement of the primary shaft assembly of Figure 29 and Figure 30;
Figure 34 illustrates a tertiary gear of the gear arrangement of the primary shaft assembly of Figure 29 and Figure 30;
Figure 35 illustrates an isometric view of the ratchet of the primary shaft assembly of Figure 29 and Figure 30;
Figure 36 illustrates an isometric view of a link of the primary shaft assembly of Figure 29 and Figure 30;
Figure 37 illustrates an isometric view of a pawl of the primary shaft assembly of Figure 29 and Figure 30;
Figure 38 illustrates an assembled view of a secondary shaft assembly;
Figure 39 illustrates an exploded view of the secondary shaft assembly of Figure 38;
Figure 40 illustrates a secondary gear of the secondary shaft assembly of Figure 38 and Figure 39;
Figure 41 illustrates tertiary pinion of the secondary shaft assembly of Figure 38 and Figure 39; and
Figure 42 illustrates a cam on the charging shaft of the charging system.


DETAILED DESCRIPTION OF THE INVENTION
The invention will now be described with reference to the accompanying drawing which does not limit the scope and ambit of the invention. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
In an electric power system, switchgear is used for protection against electrical faults such as such as short-circuit, overload, and earth faults. The switch gear is a

combination of electrical disconnect switches, fuses or circuit breakers used to control, protect and isolate electrical equipment. The switchgear is used both to de-energize equipment to allow work to be done and to clear faults downstream. The efficient operation of the switchgear is important for ensuring proper, efficient operation and reliability of the electricity supply system.
Generally, electrical faults such as short circuiting, overloading and earth faults in a power distribution network of a power distribution system may cause irreparable damage to the power distribution system. Further, such electrical faults may also cause fire hazards. The switchgear is a safety system that utilizes a combination of electrical dis-connect switches, fuses and circuit breakers for ensuring safety. A circuit breaker is an automatically operated electrical switch that cuts off electrical flow to the remaining power distribution network or isolates the faulty power distribution network in an event of a possible electrical fault, such as short-circuit, overload, and earth faults, thereby protecting the power distribution system against damages caused by short-circuiting or overloading. The circuit breaker is generally an electro-magnetic device that localizes the electrical fault by isolating the faulty power distribution network, thereby preventing damage to the entire power distribution system. More specifically, a trip unit detects a fault conditions based on current and voltage measurements and issues a trip command to the circuit breaker. The circuit breaker in-turn, by interrupting the electrical continuity immediately discontinues electrical flow to the remaining power distribution network, thereby isolating the faulty power distribution network and protecting the remaining power distribution network against any further damage.
As the switch gear mechanism is an electrical safety system that includes a plurality of circuit breakers, fuses and other electrical disconnect switches that enables the switch gear mechanism to redundantly prevent any damage to the power distribution system due to electrical faults such as such as short-circuit, overload, and earth faults. As the circuit breaker trips in case of an electrical fault, the power supply to the trip unit of the circuit breaker as well as other elements of the switch gear mechanism is disrupted. The circuit breaker is generally powered through a

current transformer. Further, as the circuit breaker trips, there is no flow of electrical current to the circuit breaker and no power is available for operating the elements of the conventional switch gear mechanism. The conventional switchgear mechanism utilizes a charging system that uses gearboxes using worm-worm wheel gears for speed reduction. Further, the charging system for the conventional switch gear mechanism fails to provide provision for automatic electrical and mechanical cut-off. As the conventional charging system fail to provide automatic mechanical cut-off, the assembly of switch gear mechanism and the charging system is subjected to high intensity jerks and vibrations that are detrimental for the efficient operation of the switch gear mechanism and the charging system. Further, the worm wheels used in the charging system for the conventional switch gear mechanism are expensive, less reliable, are prone to frequent failure, require regular maintenance and have low wear life.
The present disclosure envisages a charging system for a switch gear assembly that ameliorates the drawbacks associated with the conventional charging systems for switch gear assembly. More specifically, the charging system for switch gear mechanism in accordance with the present disclosure eliminates use of gearboxes having worm-worm wheel gears for speed reduction, thereby eliminating drawback associated with worm-worm wheel gears. The charging system for switch gear mechanism uses bevel gears for motion transmission instead of the worm -worm wheel gears. The use of bevel gear also reduces the cost and enhances service life and wear life of the charging system. The charging system for switch gear mechanism has provision for automatic mechanical cutoff and, electrical cutoff, thereby the charging system in accordance with the present invention eliminates high intensity jerks and vibrations experienced by the assembly of switch gear mechanism and the charging system. The charging system for switch gear mechanism utilizes a motor and a gearbox to operate the switch gear mechanism. The charging system in accordance with the invention addresses the need to charge the switch gear mechanism electrically and automatically. The charging system in accordance with the present invention is compatible with a variety of switch gear mechanisms.

The charging system of the present invention includes a charger assembly (1) and a mechanism assembly (2) as shown in Figure 1. The charger assembly (1) includes the gearbox assembly (11) and the motor assembly (12). The gearbox assembly (11) includes the rear housing assembly (111), the front housing assembly (112), the top plate assembly (113) and the primary shaft assembly (114).
The rear housing assembly (111) includes the rear housing (1111), bushes in the rear housing (1112), bushes in the rear assembly, top land (1113) in the rear assembly, Roller-cam for the cut-off assembly (1114), pivot shaft for the electrical cutoff (1115), Electrical cutoff lever (1116), and a plurality of limit switches (1117) as shown in Figure 11 and Figure 12. Figure 11 illustrates an assembled view of the rear housing assembly (111). Figure 12 illustrates an exploded view of the rear housing assembly (111). Figure 13 illustrates an isometric view of a rear housing (1111) of the rear housing assembly (111). Figure 14 illustrates an isometric view of a bush (1112) used in the rear housing assembly (111). Figure 15 illustrates an isometric view of a roller cam for cut-off assembly (1114) of the rear housing assembly (111). Figure 16 illustrates an isometric view of a pivot shaft for electrical cut-off (1115) of the rear housing assembly (111). Figure 17 illustrates an isometric view of an electrical cut-off lever (1116) of the rear housing assembly (111). Figure 18 illustrates an isometric view of limiting switches (1117) of the rear housing assembly (111). The electrical cut-off lever (1116) has a first end and a second end, wherein the first end of the electrical cut-off lever (1116) is actuated by rotation of the roller cam of the cut-off assembly (1114) to facilitate rotation of the electrical cut-off lever (1116) over the pivot shaft for electrical cut-off (1115). The plurality of limit switches (1117) are actuated by a second end of the electrical cutoff lever (1116) as the second end of electrical cut-off lever (1116) presses against the limit switches (1117) due to rotation of the electrical cut-off lever (1116). The use of limit switches (1117) facilitates achieving canonical relation with the charging shaft position and sensing electrical cut-off by mechanical motion. The electrical charging system in accordance with the present invention provides unidirectional, controlled, discrete rotational motion.

The front housing assembly (112) includes bushes (1121) in the front housing, mounting holes (1122) in the front cover, front housing (1123) as shown in Figure 20. Figure 19 illustrates an isometric view of the bush (1121) for a front housing of a front housing assembly (112). Figure 20 illustrates an isometric view of the front housing (1123) of the front housing assembly (112).
The top plate assembly (113) includes a shaft (1131) in the top plate assembly (113), a primary helical gear (1132), a bush (1133) for primary bevel pinion and a top plate (1136) as illustrated in Figure 21 and Figure 22. Figure 21 illustrates an assembled view of the top plate assembly (113). Figure 22 illustrates an exploded view of the top plate assembly (113). Figure 23 illustrates an isometric view of the shaft (1131) of the top plate assembly (113). Figure 24 illustrates an isometric view of the primary helical gear (1132) of the top plate assembly (113). Figure 25 illustrates an isometric view of the bush (1133) for primary helical gear (1132) of the top plate assembly (113). Figure 26 illustrates an isometric view of a primary bevel gear (1134) of the top plate assembly (113). Figure 27 illustrates an isometric view of a bush (1135) for primary bevel pinion of the top plate assembly (113). Figure 28 illustrates an isometric view of a top plate (1136) of the top plate assembly (113).
The primary shaft assembly (114) includes a primary shaft (1141) as illustrated in Figure 29 and Figure 30. The primary shaft assembly (114) includes a gear arrangement, a link (1146), a ratchet (1145) and a pawl (1147). The gear arrangement generally includes bevel gear for transmission instead of worm-worm wheel gearing and as such eliminates the. drawbacks associated with use of worm-worm wheel gears. The gear arrangement generally includes a bevel gear (1142), a secondary pinion (1143) and a tertiary gear (1144). The gear arrangement derives power from a pinion. The primary shaft (1141) is functionally coupled to the gear arrangement and is driven by gears of the gear arrangement. The link (1146) is mounted on the primary shaft (1141) and rotates along with the primary shaft (1141). The pawl (1147) is pivotably mounted on the link (1146) and has a cam

disposed thereon, wherein the pawl (1147) is urged against teeth of the ratchet (1145) by a spring element for facilitating engagement between the pawl (1147) and the teeth of the ratchet (1145), the cam engages with the roller cam of the cut-off assembly (1114) to cause actuation thereof The use of pawl (1147) and ratchet (1145) arrangement assists in achieving discrete stroke of terminal gear train, unidirectional motion and selective mechanical cut-off. Figure 31 illustrates an isometric view of the primary shaft (1141) of the primary shaft assembly (114). Figure 32 illustrates the bevel gear (1142) of the gear arrangement of the primary shaft assembly (114). Figure 33 illustrates the secondary pinion (1143) of the gear arrangement of the primary shaft assembly (114). Figure 34 illustrates the tertiary gear (1144) of the gear arrangement of the primary shaft assembly (114). Figure 35 illustrates an isometric view of the ratchet (1145) of the primary shaft assembly (114). Figure 36 illustrates an isometric view of the link (1146) of the primary shaft assembly (114). Figure 37 illustrates an isometric view of the pawl (1147) of the primary shaft assembly (114).
Figure 38 illustrates an assembled view of a secondary shaft assembly (115). Figure 39 illustrates an exploded view of the secondary shaft assembly (115). Figure 40 illustrates a secondary gear (11.51) of the secondary shaft assembly (115). Figure 41 illustrates tertiary pinion (1152) of the secondary shaft assembly (115). Figure 42 illustrates a cam on the charging shaft of the charging system.
The primary shaft assembly (114) and the secondary shaft assembly (115) are assembled into the rear housing (1111) axially. The secondary pinion (1143) meshes with the secondary gear (1151) and the tertiary pinion (1152) meshes with the tertiary gear (1144). The front housing assembly (112) is assembled into this assembly such that the bushes (1121) in the front housing (1123) match the respective axes of the primary shaft assembly (114) and the secondary shaft assembly (115). The mounting holes of the front housing (1123) meet with those of the rear housing (1111). The top plate assembly (113) is assembled such that the bevel gear (1142) meshes with the bevel pinion (1134) and the top plate (1136)

rests on the land of the rear housing (1111). The mounting holes of the top plate (1136) match with those of the rear housing top.
The motor assembly (12) fits on top of the top plate assembly (113). The motor assembly (12) includes a motor (121), a motor shaft (122) and a pinion (123). The motor shaft (122) is driven by the motor and the pinion (123) is mounted on the motor shaft (122), the pinion (123) drives the gear arrangement of the primary shaft assembly (144). The motor assembly (12) further includes a motor mounting plate (124), a plurality of mounting plate bolts (125).
The motor (121) in the top plate assembly (113) rotates the primary pinion (123), which in turn rotates the primary helical gear (1132). The bevel pinion (123) is compounded with the primary helical gear (1132) and rotates there-with. The bevel gear rotates with the bevel pinion (123) along the primary shaft axis. The secondary pinion (1143) is compounded with the bevel gear (1142) and rotates there-with. The secondary gear (1151) rotates along the secondary shaft (115) axis as shown in Figure 38 and Figure 39. The secondary gear (1151) is compounded with a tertiary pinion (1152. The rotation of the tertiary pinion (1152) is transmitted to the tertiary gear (1144). The tertiary gear (1144) houses the ratchet (1145) mounted along the same axis as the former. The engagement of the pawl (1147) with the ratchet (1145) actuates the motion of the primary shaft (1141) as shown in Figure 5. The pawl (1147) is mounted on the link (1146), which is an extension of the primary shaft (1141). The pawl (1147) locks and rotates the primary shaft (1141). Hence the motor (121) powers the motion of the mechanism (2) as shown in Figure 6.
Referring to Figure 5, Figure 6, Figure 7 and Figure 8, the interaction between the pawl (1147) and the roller cam (1114) is illustrated. The user derives the intended motion through the primary shaft (1141). The roller cam (1114) is disposed inside the rear housing assembly (111) as shown in Figure 7. The pawl (1147) has a cam profile (11471) which makes the pawl (1147) rotate away from the ratchet (1145)

and the pawl (1147) loses its interaction with the ratchet on contact. The roller cam (1114) is placed at a predetermined position along the motion curve of the pawl (1147) to disengage the pawl (1147).
Referring to Figure 2 and Figure 3, means to cutoff the power to the mechanism assembly (2) is disclosed. The mechanism assembly (2) includes a cam (22) assembled on the charging shaft (21) of the mechanism assembly. A pip (211) present in the cam interacts with the limit switches (1117) placed on the gear box assembly (11), thereby pressing the limit switch and cutting the power to the motor (121). The electrical charging system in accordance with the present invention utilizes detachable pawl and ratchet mechanism, which is mounted on separate bodies placed rotatably along a common axis. The pawl (1147) is mounted pivotably on an extended part of the primary shaft (1141), the rotational axis of the pawl (1147) is at an offset with that of the primary shaft (1141). The pawl (1147) rides a ratchet which can be constructed as a monolithic part of another body mounted pivotably on the axis of the primary shaft (1141).
TECHNICAL ADVANCEMENTS
The electrical charging system for switch gear mechanism has several technical advantages including but not limited to the realization of:
• an electrical charging system for a switch gear mechanism that eliminates the drawback associated with conventional charging systems that uses gearboxes using worm-worm wheel gears for speed reduction;
• a charging system for switch gear mechanism that has provision for automatic mechanical cutoff and electrical cutoff;
• a charging system for a switch gear assembly that is simple in construction and convenient to use;
• a charging system for a switch gear assembly that uses an alternate and readily available source of power or that can be manually powered for charging and operating the elements of the switch gear assembly;

• a charging system for a switch gear assembly that is reliable and ensures safety of the electrical distribution system;
• a charging system for a switch gear assembly that is sturdy, that does not fail and has longer service life;
• a charging system for a switch gear assembly that requires less maintenance;
• a charging system for a switch gear assembly that is inexpensive;
• a charging system for a switch gear assembly that may be easily retrofitted and used with any of the conventionally known switch gear assembly and electrical distribution system; and
• a charging system for a switch gear assembly that ensures proper maintenance and safety of the power distribution system.
Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the invention. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the invention as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall

within the scope of the invention, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the invention. These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby 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. An electrical charging system for a switch gear mechanism, said electrical charging system comprising: • a charger assembly comprising:
o a gear box assembly comprising:
■ a rear housing assembly comprising:
a pivot shaft for electrical cut-off; a roller cam for cut-off assembly; an electrical cut-off lever mounted on said pivot shaft for electrical cut-off, a first end of said electrical cutoff lever adapted to be actuated by rotation of said roller cam of said cut-off assembly to facilitate rotation of said electrical cut-off lever over said pivot shaft for electrical cut-off; and
- a plurality of limit switches actuated by a second end
of said electrical cut-off lever as said second end of
electrical cut-off lever presses against said limit
switches due to rotation of said electrical cut-off
lever;
■ a front housing assembly;
■ a top plate assembly; and
■ a primary shaft assembly comprising:
a gear arrangement adapted to derive power from a pinion;
- a primary shaft functionally coupled to said gear
arrangement and adapted to be driven by gears of
said gear arrangement;

- a link mounted on said primary shaft and adapted to rotate along with said primary shaft;
- a ratchet; and
- a pawl pivotably mounted on said link and has a cam disposed thereon, wherein said pawl is urged against teeth of said ratchet by a spring element for facilitating engagement between said pawl and said teeth of said ratchet, said cam adapted to engage with said roller cam of said cut-off assembly to cause actuation thereof; and
o a motor assembly comprising:
■ a motor;
■ a motor shaft driven by said motor; and
■ a pinion mounted on said motor shaft and adapted to drive said gear arrangement of said primary shaft assembly; and
• a mechanism assembly comprising; o a charging shaft; and
o a charging shaft cam mounted on said charging shaft and provided with male protrusions configured thereon.
2. The electrical charging system as claimed in claim 1, wherein said gear arrangement comprises a secondary pinion, a bevel gear and a tertiary gear.
3. The electrical charging system as claimed in claim 1, wherein said motor of said motor assembly is a DC motor.
4. The electrical charging system as claimed in claim 1, wherein a rear housing and a front housing of said rear housing assembly and said front housing assembly are made of metal sheets having a plurality of legs bent from the same plane of the sheet.

5. The electrical charging system as claimed in claim 1, said pawl and said ratchet are detachably mounted on separate bodies placed rotatably along a'common axis.