TECHNICAL FIELD
The subject matter described herein, in general, relates to a brush plate assembly for a motor used in various electrical equipments. BACKGROUND
A brush plate assembly is provided with a resilient mechanism to impel a brush towards a commutator attached to an armature of a motor, which is used in various electrical equipments. A contact face of the brush, which comes in contact with the commutator, is biased towards the commutator by a brush spring. Such a brush spring can be located at the rear or on a side of the brush and is housed in a brush box along with the brush. The brush box is provided with clinching profiles on the base of the brush box to hold the brush box on the brush plate. The clinching profiles pass through clinching slots provided on the brush plate, thereby attaching the brush box to the brush plate. It is observed that usually two-point clinching is used which causes the brush box to move along the surface of the brush plate. Due to the movement of the brush box along the surface of the brush plate, the brush inside the brush box can not maintain the contact with the commutator with a constant pressure which further affects the working of the motor.
Furthermore, the brush plate assembly operates under extreme conditions wherein temperature of the brush plate assembly can be high. The parts of the brush plate assembly are exposed to dust, moisture etc. Due to the above conditions, the brush plate assembly is not able to function properly. Further, the brush is not able to maintain contact with the commutator at a constant pressure. This requires the brush spring to move only along the axis of the brush box and not otherwise.

further, during the manufacture of the motor, the commutator is inserted into a centre hole to make contact with the brushes. Because the brushes are biased towards the commutator, the brushes need to be held in the brush box to allow for the insertion of the commutator into the brush plate assembly. Conventionally, a separate disposable or reusable brush retention device is used to retain the brushes. For example, a tube is placed in between the brushes to hold them and is removed after the commutator is installed. Alternatively, pins or clips are used to retain the brushes until the commutator assembly is installed. After installation, the pins or clips can be removed. These methods of manufacture add extra devices to the manufacture of electric motors and other devices using brushes. As a result the commutator is usually not positioned appropriately.
The challenge therefore is to provide a brush plate assembly that ensures compact clinching of the brush plate by the brush box. Further there is a need to temporarily hold the brush in order to achieve the proper installation of the commutator. SUMMARY
the subject matter described herein is directed to a brush plate assembly of a motor that provides firm attachment between a brush box and a brush plate. Further, the brush box includes a brush, which can be temporarily held in a place while installing a commutator.
The brush plate assembly includes a brush plate and a plurality of brush boxes. the brush plate is a metal plate having a centre hole for inserting a commutator therein, fhc centre hole is provided substantially at the centre of the brush plate. A plurality of extended portions is provided on the periphery of the centre hole. Each extended portion is provided with at least three clinching slots therein. The clinching slots are formed such

that two of the clinching slots are placed towards opposite ends of the extended portions. Further one slot is provided offset from the line joining the two slots.
The brush box is attached to the brush plate via the clinching profiles provided at the bottom side of the brush box. The clinching profiles pass through the clinching slots thereby attaching the brush box and brush plate firmly. At least three clinching profiles are provided to ensure the firm attachment.
Further, the brush box, having a top side and a bottom side, comprises a brush spring, a brush, a braid, and atleast one anchoring profile. The brush has a contact face that comes in contact with the commutator and is impelled towards the commutator by the brush spring housed in the brush box. The non-contact face of the brush is further attached to a braid. During the insertion of the commutator in the centre hole, the braid is affixed to the anchoring profile provided on the top of the brush box due to which the brush is hold temporarily inside the brush box. Thus proper insertion of commutator in the centre hole is achieved without any additional device, which was earlier utilized for inserting the commutator in the centre hole during the manufacturing of the motor.
In accordance with an embodiment of the present subject matter, the brush plate assembly described herein ensures firm attachment of the brush box with the brush plate by providing atleast three point clinching. This avoids the movement of the brush box along the surface of the brush plate, thereby enhancing the performance of the brush plate assembly.
fhese and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description and appended

claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. BRIEF DESCRIPTION OF DRAWINGS
the above and other features, aspects, and advantages of the subject matter will be better understood with regard to the following description, appended claims, and accompanying drawings where:
Fig.l (a) illustrates a top view of a brush plate assembly with a commutator inserted therein in accordance with the present subject matter.
Fig.l (b) illustrates a top view of the brush plate assembly of Fig.l (a) without a commutator.
Fig.2 illustrates a top view of a brush plate of the brush plate assembly of Fig.l (a).
Fig.3 (a) illustrates the front view of a brush box of the brush plate assembly of Fig.l (a).
Fig.3 (b) illustrates the cross-sectional side view the brush box of Fig.3 (a).
Fig.4 illustrates the perspective view of the brush box of Fig.3 (a).
Fig.5 (a) illustrates the side view of a brush with a braid.
Fig.5 (b) illustrates the front view of a brush of the brush plate assembly of Fig. 1
(a).
Fig.6 (a) & Fig.6 (b) illustrates the side view of the brush of the brush box of
Fig.3 (a), during the affixed and released conditions.

DETAILED DESCRIPTION
A brush plate assembly for a motor comprises a brush plate and a plurality of brush boxes. The brush plate is a metal plate having a centre hole for inserting a commutator therein. The centre hole is provided substantially at the centre of the brush plate. A plurality of extended portions is provided on the periphery of the centre hole. Each extended portion is provided with atleast three clinching slots therein. The clinching slots are formed such that at least two of the clinching slots are furthest, i.e., are placed towards diagonally opposite ends of the extended portion and at least one slot is provided at an offset from the line joining these two slots.
The brush box is attached to the brush plate through the clinching profiles provided at the bottom side of the brush box. The clinching profiles are the protrusions which can be bent to grip the brush plate inorder to attach the brush box to the brush plate. The clinching profiles pass through the clinching slots, thereby attaching the brush box and the brush plate firmly. At least three clinching profiles are provided to ensure firm attachment. Length of the clinching profiles is such that the clinching profiles are bent to the lower side of the brush plate.
Further, the brush box, having a top side and a bottom side, comprises a brush spring, a brush, a braid, and atleast one anchoring profile. The brush has a contact face that comes in contact with the commutator and a non-contact face to which a braid, made of a conducting material, is attached for electrical connectivity. The brush is made to contact with the commutator by the brush spring, which exerts an impelling force on the non-contact face of the brush. The brush spring is housed in the brush box.

Further, the braid is affixed to an anchoring profile provided on the top of the brush box such that the anchoring profile is positioned opposite to the contact face of the brush. The anchoring profile has a slot which easily affixes the braid thereto. The anchoring profile may be provided on the sides of the brush box.
f he braid affixed to the anchoring profile, holds the brush temporarily during the insertion of the commutator in the centre hole. Moreover, the length of the braid is such that the brush maintains a retracted position during the affixing of the braid to the anchoring profile and maintains a relaxed original position during the release of the braid from the anchoring profile.
Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein.
Fig.l (a) illustrates a top view of a brush plate assembly 100 with a commutator inserted therein in accordance with the present subject matter.
Fig.l (b) illustrates a top view of the brush plate assembly of Fig.l (a) without a commutator.
The brush plate assembly 100 is usually mounted on a motor end-cap. The brush plate assembly 100 comprises a brush plate 105 having a centre hole 110. The centre hole 110 is provided substanfially at the centre of the brush plate 105. The brush plate is normally made of plastic, but can also be made of a ceramic or a plastic with a metal backing. The brush plate assembly 100 further comprises two brush boxes 115(a) and 115(b) attached to the brush plate 105. As shown in Fig. 1(b), the brush boxes 115(a) and

115(b), which are identical to each other, are placed on the periphery of the centre hole 110 such that the brush box 115(a) is placed diagonally opposite to the brush box 115(b). Further, a commutator 120 is inserted in the centre hole 110 as shown in Fig.l (a).
In continued reference, Fig.2 illustrates a top view of the brush plate 105 having the centre hole 110 and two extended portions 205(a) and 205(b). The brush boxes 115(a) and 115(b) are attached to the extended portions 205 (a) and 205 (b) respectively. The extended portions 205(a) and 205(b) are provided on the periphery of the centre hole 110 such that the extended portions 205(a) and 205(b) are diagonally opposite to each other.
The following description is provided with reference to the extended portion 205(a) and the corresponding brush box 115(a). It will be understood that the extended portion 205(b) and the corresponding brush box 115(b) will have similar features that work in a similar manner.
The extended portion 205(a) has three clinching slots 210(a), 210(b), and 210(c), collectively referred to as clinching slots 210, thereon which extend through the brush plate 105 from the top side to the bottom side of the brush plate 105. The clinching slots 210 are provided herein to retain the brush box 115(a) thereon. The clinching slots 210 are provided in such a way that the clinching slots 210(a) and 210(c) are furthest from each other and the clinching slot 210(b) is provided at an offset from the line joining the clinching slots 210(a) and 210(c). Furthermore, the clinching slot 210(b) is preferably provided such that the clinching slot 210(b) is substantially equidistant from the clinching slots 210(a) and 210(c). The equidistance of the clinching slot 210(b) from the clinching

slots 210(a) and 210(c) provides uniform stress distribution during the clinching of brush plate 105 by the brush box 115(a).
Fig.3 (a) & Fig.3 (b) illustrate an exemplary front view and cross-sectional side view of the brush box 115(a) respectively. The brush box 115(a) is normally made of brass or bronze, but is sometimes made of plastic. As shown in Fig.3 (a) 4& Fig,3 (b), the brush box 115(a) has two sides 305(a) and 305(b), a base 310, a top 315, a mouth 320 and an anchoring profile 325 mounted on the top 315. The brush box 115(a) is attached to the extended portion 205(a) such that the mouth 320 is in proximity of the commutator 120.
The sides 305(a) and 305(b) have D-shaped contours as shown in Fig.3 (a). The shape of the contours on the sides of the brush box 115(a) may be D-shaped, circular, elliptical, or any other shape. The shape of the contour on the two sides of the brush box 115(a) may either be the same or different. Further, the base 310 and the top 315 may or may not be contoured.
The bottom side of the base 310, which will come in contact with the brush plate 105, is provided with the clinching profiles 330(a), 330(b) and 330(c), collectively referred to as clinching profiles 330. The clinching profiles 330 are provided in the same manner as the clinching slots 210 in order to fit thereinto respectively. The length of the clinching profiles is more than the thickness of the brush plate such that the profiles may be bent on the bottom side of the base plate of the brush plate to securely hold the brush box. The brush box 115(a) is firmly attached to the brush plate 105 via the clinching profiles 330.

The embodiment described above may have many variations, each of which would be obvious to a person skilled in the art. The brush plate may have more than three clinching slots. The clinching slots may be arranged on the basis of known engineering concepts and/or routine experimentation. The brush box will accordingly have clinching profiles that correspond to the clinching slots.
Fig.4 illustrates the perspective view of the brush box 115(a) comprising a brush 405 which is impelled towards the commutator 120 by a brush spring 410. The brush 405 may be made of carbon or any other suitable material. The brush 405 has a contact face and a non-contact face. The contact face touches the commutator 120. The brush spring 410 comes into contact with brush on the non-contact face brush 405. The brush spring 410 is wound such that the brush spring 410 applies a biasing spring force to the brush 405 and pushes the brush 405 towards the commutator 120.
The brush spring 410 can be a conventional compression coil spring that is capable of impelling the brush 405 towards the commutator 120 with the desired pressure in the extended position. The diameter of the brush spring 410 is made such that it can freely enter into the mouth 320 of the brush box 115(a). Further, the brush spring 410 fits in easily inside the brush box 115(a) due to the D-shaped contours provided on the sides 305(a) and 305(b). The shape of the contour of the sides 305(a), 305(b) is in accordance with the shape of the brush spring 410. Further, the contours have a diameter greater than the diameter of the brush spring 410. The length of the brush spring 410 is in accordance with the length of the brush box 115(a), length of the brush 405 and the pressure requirements.

fig.5 (a) illustrates a side view of a brush of the brush plate assembly. A braid 505, as shown in Fig,5 (a), is press attached to the brush 405 for electrical connectivity. The braid 505 can be made of copper or any other appropriate conducting material. The braid 505 is press attached or attached by any other conventional means to the non-contact face of the brush 405. The thickness of the braid 505 is such that required current may flow therethrough. Moreover, the length of the braid 505 is such that it may be attached to the anchoring profile 325 in order to secure the brush 405 in a retracted position inside the brush box 115(a).
In continued reference, Fig.5 (b) illustrates a detailed front view of the brush 405. According to one embodiment, the braid 505 is an integral part of the brush 405. A loop is formed at the end of the braid 505.The loop is put over the anchoring profile 325 for temporarily holding the brush 405 in the retracted position. The length and shape of the anchoring profile is provided in accordance with the compensation of the thickness of the braid and the force exerted on the anchoring profile by the brush spring.
The anchoring profile may be located on the top, sides or the side of the brush box opposite to the mouth of the brush box. More than one anchoring profile may also be used. In that case, the anchoring profiles are distributed appropriately on the top or the sides of the brush box based on known engineering concepts and/or routine experimentation.
In another embodiment of the present subject matter, as shown in Fig.6 (a) and Fig.6 (b), the braid 505 may be attached or removed from the anchoring profile 325. The braid 505 is affixed to the anchoring profile 325 to retract the brush 405 inside the brush box 115(a). Similarly a braid is affixed to an anchoring profile provided on the brush box

115 (b) due to which the corresponding brush is retracted inside the brush box 115(b). Both the brushes attached to the corresponding braids are retracted inside the respective brush boxes due to the affixing of the respective braids to the respective anchoring profile.
The retraction of the brushes allows easy insertion of the commutator 120 in the centre hole 110. The commutator 120 is fitted with ease into the brush plate assembly 100 by initially keeping the brushes in the retracted position. After the commutator 120 is in place, the braids can be released from the respective anchoring profiles so that the brushes, under pressure from the brush springs, come into contact with the commutator 120. Due to the ease in the fitting of commutator in the base plate assembly 100, the assembling process is simplified during the manufacture of the motor.
The aforementioned versions of the subject matter and equivalent thereof have many advantages, including those which are described below.
The brush plate assembly of the present subject matter ensures firm attachment between the brush box and the brush plate by providing atleast three point clinching. The three point clinching is provided in such a way that it has minimized the movement of the brush box on the surface of brush plate. This further ensures that the brushes maintain contact with the commutator at a constant pressure, thereby enhancing the performance of the brush plate assembly. Further, the brush moves only along the longitudinal axis of the brush box and not otherwise.
Another advantage of the present subject matter is the ease in fitting of the commutator in the base plate assembly during the manufacturing of a motor. Further proper insertion of the commutator in the centre hole has been achieved. Moreover, the

need for any additional device utilized for inserting the commutator in the centre hole during the manufacturing of the motor is eliminated.
Although the subject matter has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the subject matter, will become apparent to persons skilled in the art upon reference to the description of the subject matter. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present subject matter as defined.

I/We claim:
1. A brush plate assembly for a motor, said brush plate assembly comprising: a brush plate having
a centre hole for inserting a commutator therein, a plurality of extended portions on the periphery of said centre hole, wherein each of said extended portions include atleast three clinching slots,
wherein said clinching slots are formed such that atleast two of said clinching slots are furthest and atleast one slot is provided at an offset to the line joining said atleast two slots; and a plurality of brush boxes having a top side and a bottom side, wherein said brush box comprises
a brush spring housed in said brush box;
a brush having a contact face, wherein said brush is housed in said
brush box and said contact face contacts said commutator,
wherein said brush spring impels said brush towards said commutator; a braid attached to said brush;
atleast one anchoring profile on the periphery of said brush box, wherein said braid is affixed to said anchoring profile to temporarily hold said brush away from said commutator; and

atleast three clinching profiles to fit into each of said clinching
slots; wherein each of said brush boxes are attached to each of said extended portions through said clinching profiles fitted into said clinching slots.
2. The brush plate assembly as claimed in claim 1, wherein said anchoring profile is
located on the top of said brush box such that said anchoring profile is opposed to
said contact face of said brush.
3. The brush plate assembly as claimed in claim 1, wherein said anchoring profile is
located on the sides of said brush box such that said anchoring profile is opposed
to said contact face of said brush.
4. The brush plate assembly as claimed in claim 1, wherein length of said clinching
profiles is such that said clinching profiles are bent to the lower side of said brush
plate.
5. The brush plate assembly as claimed in claim 1, wherein said braid is made of a
conducting material.
6. The brush plate assembly as claimed in claim 1, wherein length of said braid is
such that said brush is in retracted position inside said brush box by affixing said
braid to said anchoring profile.
7. The brush plate assembly as claimed in claim 1, wherein a slot is provided on said
anchoring profile to affix said braid to said anchoring profile.