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, 2005
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
A modular brush gear assembly for electrical rotating machines.
APPLICANTS :
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR (S):
Pandya Ankit and Upadhyay Amarendra; both of Crompton Greaves Limited, Machine (M7) Division, Industrial Area, MPAKVN, Mandideep - 462046, Madhya Pradesh, India; both 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 motor assemblies.
Particularly, this invention relates to commutators and brushes of motors.
More particularly, this invention relates to a modular brush gear assembly for electrical rotating machines.
BACKGROUND OF THE INVENTION:
A motor is an electromechanical assembly which comprises stator, rotor, and commutator. While the stator is the stationary part of a rotor motor system, the rotor is the non-stationary part of a rotary motor.
A commutator is a rotary electrical switch in certain types of electric motors or electrical generators that transfer current from stationary part of the machine to its rotating part. A commutator is a common feature of a DC motor. This commutator consists of a number of segments of copper or of other suitable electrical conducting substance places together in the form of a ring with a sheet of electrical insulating substance between every two adjacent segments.
A commutator typically consists of a set of copper segments, fixed around part of the circumference of the rotating part of the machine (the rotor), and a set of spring-loaded brushes fixed to the stationary frame of the machine. The brushes are used to contact the surface of the commutator. An external source of current (for a motor) or electrical load (for a generator) is connected to the brushes.

The brushes are held by a brush gear assembly. DC motor transfers armature current through the brushes to the commutator. Depending upon the motor rating and current carrying capability, thereof, the brush size varies.
The brush gear assembly includes a plurality of pockets which serve as brush holders. In a brush holder pocket there are four side walls which are perpendicular to each other. In conventional brush holders of the prior art, these pockets have a fixed size. As the brush size changes, these brush holders also need to have changed dimensions in order to allow for appropriate fitting of brushes in them.
There is a need for a modular and dimension-changeable brush holder, and a modular and dimension-changeable brush gear assembly thereof.
OBJECTS OF THE INVENTION:
An object of the invention is to provide modularity of fitment of brushes in a brush gear assembly.
Another object of the invention is to provide a gripped fitment of brushes in a brush gear assembly.
Yet another object of the invention is to allow a fitment of brushed gear assembly which can be changed according to size of brushes.
Still another object of the invention is to provide a dimension-changeable of brushed gear assembly which can be changed according to size of brushes.

SUMMARY OF THE INVENTION:
According to this invention, there is provided a modular brush gear assembly for a rotating electrical machine having serially aligned box-slots for holding brushes, said assembly comprises: a first axially mounted lever mechanism adapted to provide operative inward and operative outward movement to at least a first wall which defines the breadth-wise pocket size of the box-slot of the brush gear assembly; a second axially mounted lever mechanism adapted to provide operative inward and operative outward movement to at least a second wall which defines the length-wise pocket size of the box-slot of the brush gear assembly, thereby provisioning variable inner peripheral dimensions accounting for different breadths and hence, different box-slot dimensions for different contoured assemblies, correspondingly.
According to this invention, there is also provided a rotating electrical machine with a modular brush gear assembly having serially aligned box-slots for holding brushes, said assembly comprises: a first axially mounted lever mechanism adapted to provide operative inward and operative outward movement to at least a first wall which defines the breadth-wise pocket size of the box-slot of the brush gear assembly; a second axially mounted lever mechanism adapted to provide operative inward and operative outward movement to at least a second wall which defines the length-wise pocket size of the box-slot of the brush gear assembly, thereby provisioning variable inner peripheral dimensions accounting for different breadths and hence, different box-slot dimensions for different contoured assemblies, correspondingly.
Typically, said inner peripheral dimensions correlate in dimensions to brush dimensions.

Typically, said at least first lever mechanism is in mechanical communication with a rack and pinion mechanism such that said at least first wall is in direct communication with a corresponding rack part of said rack and pinion mechanism.
Typically, said at least first lever mechanism is in mechanical communication with a rack and pinion mechanism such that said at least first wall is operated by a corresponding pinion part of said rack and pinion mechanism.
Typically, said at least second lever mechanism is in mechanical communication with a rack and pinion mechanism such that said at least second wall is in direct communication with a corresponding rack part of said rack and pinion mechanism.
Typically, said at least second lever mechanism is in mechanical communication with a rack and pinion mechanism such that said at least second wall is operated by a corresponding pinion part of said rack and pinion mechanism.
Typically, said assembly includes a locking mechanism adapted to lock the movement of walls so that the box dimensions remain fixated for receiving the brushes of appropriate dimensions.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates a brush gear assembly of the prior art with brush pockets.
The invention will now be described in relation to the accompanying drawings, in which:
Figure 2 illustrates an isometric solid diagram view of the brush gear assembly with the mechanism to change brush pocket size; and

Figure 3 illustrates a schematic view of the mechanism to change brush pocket size of the brush gear assembly.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates a brush gear assembly (100) of the prior art.
According to the prior art, there are provided box-slots (12) linearly aligned at one end of the brush gear assembly. These box slots are the brush pockets. Each of the box slots receives a brush which facilitates current transfer. As the motor rating varies, brush dimensions vary. Here, the brush holding box-slots cannot be modified according to the brush dimensions. Thus, no modularity is available. The entire brush gear assembly needs to be replaced, according to the prior art, for varying brush dimensions.
According to this invention, there is provided a modular brush gear assembly for electrical rotating machines.
Figure 2 illustrates an isometric solid diagram view of the brush gear assembly (200) with the mechanism (50) to change brush pocket size; and
Figure 3 illustrates a schematic view of the mechanism (50) to change brush pocket size of the brush gear assembly.
In accordance with an embodiment of this invention, there is provided a first axially mounted lever mechanism (22) adapted to provide operative inward and operative outward movement to at least a first wall (24) which defines the breadthwise pocket size of the box-slot of the brush gear assembly. As the at least first wall moves towards the other opposing parallel wall, the breadth decreases and the

box-slot dimensions decrease breadth-wise. As the at least first wall moves away from the other opposing parallel wall, the breadth increases and the box-slot dimensions increase breadth-wise.
In accordance with another embodiment of this invention, there is provided a second axially mounted lever mechanism (32) adapted to provide operative inward and operative outward movement to at least a second wall (34) which defines the length-wise pocket size of the box-slot of the brush gear assembly. As the at least second wall moves towards the other opposing parallel wall, the length decreases and the box-slot dimensions decrease length-wise. As the at least second wall moves away from the other opposing parallel wall, the length increases and the box-slot dimensions increase length-wise.
The lever mechanism is in mechanical communication with a plurality of rack and pinion mechanisms such that the at least first wall and the at least second wall of the box-slot is in direct communication with the corresponding rack parts (42) of the rack and pinion mechanism and each lever corresponding to the at least first wall and the at least second wall is in direct communication with the pinion parts (44) corresponding to the at least first and at least second walls that it controls.
The at least first wall is substantially orthogonal to the at least second wall. The mechanism of this invention provides pockets that can be varied in size as per requirement.
The mechanism may be modified to move pairs of opposing walls.

In accordance with yet another embodiment of this invention, there is provided a locking mechanism adapted to lock the movement of walls so that the box dimensions remain fixated for receiving the brushes of appropriate dimensions.
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 modular brush gear assembly for a rotating electrical machine having serially aligned box-slots for holding brushes, said assembly comprising: a first axially mounted lever mechanism adapted to provide operative inward and operative outward movement to at least a first wall which defines the breadth-wise pocket size of the box-slot of the brush gear assembly; a second axially mounted lever mechanism adapted to provide operative inward and operative outward movement to at least a second wall which defines the length-wise pocket size of the box-slot of the brush gear assembly, thereby provisioning variable inner peripheral dimensions accounting for different breadths and hence, different box-slot dimensions for different contoured assemblies, correspondingly.
2. An assembly as claimed in claim 1 wherein, said inner peripheral dimensions correlate in dimensions to brush dimensions.
3. An assembly as claimed in claim 1 wherein, said at least first lever mechanism is in mechanical communication with a rack and pinion mechanism such that said at least first wall is in direct communication with a corresponding rack part of said rack and pinion mechanism.
4. An assembly as claimed in claim 1 wherein, said at least first lever mechanism is in mechanical communication with a rack and pinion mechanism such that said at least first wall is operated by a corresponding pinion part of said rack and pinion mechanism.
5. An assembly as claimed in claim 1 wherein, said at least second lever mechanism is in mechanical communication with a rack and pinion

mechanism such that said at least second wall is in direct communication with a corresponding rack part of said rack and pinion mechanism.
6. An assembly as claimed in claim 1 wherein, said at least second lever mechanism is in mechanical communication with a rack and pinion mechanism such that said at least second wall is operated by a corresponding pinion part of said rack and pinion mechanism.
7. An assembly as claimed in claim 1 wherein, said assembly includes a locking mechanism adapted to lock the movement of walls so that the box dimensions remain fixated for receiving the brushes of appropriate dimensions.
8. A rotating electrical machine with a modular brush gear assembly having serially aligned box-slots for holding brushes, said assembly comprising: a first axially mounted lever mechanism adapted to provide operative inward and operative outward movement to at least a first wall which defines the breadth-wise pocket size of the box-slot of the brush gear assembly; a second axially mounted lever mechanism adapted to provide operative inward and operative outward movement to at least a second wall which defines the length-wise pocket size of the box-slot of the brush gear assembly, thereby provisioning variable inner peripheral dimensions accounting for different breadths and hence, different box-slot dimensions for different contoured assemblies, correspondingly.
9. An assembly as claimed in claim 8 wherein, said inner peripheral dimensions correlate in dimensions to brush dimensions.
10.An assembly as claimed in claim 8 wherein, said at least first lever mechanism is in mechanical communication with a rack and pinion

mechanism such that said at least first wall is in direct communication with a corresponding rack part of said rack and pinion mechanism.
11.An assembly as claimed in claim 8 wherein, said at least first lever mechanism is in mechanical communication with a rack and pinion mechanism such that said at least first wall is operated by a corresponding pinion part of said rack and pinion mechanism.
12.An assembly as claimed in claim 8 wherein, said at least second lever mechanism is in mechanical communication with a rack and pinion mechanism such that said at least second wall is in direct communication with a corresponding rack part of said rack and pinion mechanism.
13.An assembly as claimed in claim 8 wherein, said at least second lever mechanism is in mechanical communication with a rack and pinion mechanism such that said at least second wall is operated by a corresponding pinion part of said rack and pinion mechanism.
14.An assembly as claimed in claim 8 wherein, said assembly includes a locking mechanism adapted to lock the movement of walls so that the box dimensions remain fixated for receiving the brushes of appropriate dimensions.