This invention relates to a brush assembly for an electrical machine, such as, an electrical motor or generator. More particularly, though not exchisively, this invention relates to a brush assembly for a starter motor for an internal combustion engine used in motor vehicles.
It is well known that carbon brushes used inelectrical machines wear off during use and have to be replaced from time to time. To reduce this recurring cost is the object of this invention.
The brush assembly for an electrical machine, according to this invention, comprises a carbon brush, the bottom of said brush being intended in contact with the commutator of the said machine, characterised by a thin, flat electrical conductor, partly embedded in, and close to the top of, the said brush, while the free end of the said conductor is connected to a flexible metal wire braid.
This invention will now be described with reference to the
accompanying drawings, which illustrate in
Fig. 1 the known brush assembly
And, in Figs. 2 to 4, three embodiments of this invention by way of
example, and not by way of limitation.
According to the known art, illustrated in Fig. 1, the bottom B of the carbon brush C is intended for contact with the commutator D of an electrical machine, say, a starter motor tor a motor vehicle engine.

One end E of a flexible copper wire braid F (which has a near circular cross section) is embedded in the carbon brush C. The said wire braid constitutes an electrical lead for the brush C.
It will be observed that the useful length of the brush C is H, that is, the length over which the brush can safety be used until it has to be discarded, because any further use of the brush will result in the commutator D coming into direct contact with the end E of the braid and damaging the commutator.
Fig. 2 illustrates the first embodiment of this invention, according to which a thin. Hat electrical conductor J of copper is partly cmbedded in and close to the top T of, the carbon brush C. The free Qnd of the said conductor is connected to a flexible copper wire braid F. The said wire braid F constitutes an electrical lead for the conductor J.
It will be observed that the useful length of the brush C is K and that by reason of the construction aforesaid, the useful length of the brush of the said emboditnent has now increased beyond the useful length of the brush of the known assembly so much so that K is greater than H, thereby giving a longer life to the brush of the said embodiment.
In the lust embodiment (Fig.2), the portion of the conductor embedded in the brush is in the form of a copper eyelet piece having two holes (eyelets X2, While partly embedding the said conductor J in the carbon brush C, that is, while compacting carbon particles around the embedded portion of the said conductor, during manufacture; of the

We Claim:
1. A brush assembly for an electrical macMne, comprising a carbon brush, the bottom of said brush being intended for contact with the commutator of the said machine, characterised by a thin, flat electrical conductor, partly embedded in, close to the top of, the said brush, while the free end of the said conductor is connected to flexible metal wire braid.
2. A brush assembly as claimed in claim 1 wherein the embedded portion of the conductor is in the form of a metal eyelet piece. 3.A brush assembly as claimed in Claim 2 wherem the eyelet piece b provided with at least one hole or slot,

4. A brush assembly as claimed m any one of the precedmg Clamis wherein either or both sides of the embedded portion of the conductor is serrated.
5. brush assembly' as claimed in Claim 1 wherein the embedded portion of the conductor is in the form of a flexible metal wire braid with a near rectangular cross-section.
6 A brush assembly as claimed in Claim 1 wherein the embedded
portion of the conductor is in the form of a metal wire braid
initially with a near circular cross-section flattened to a near
rectangular cross-section,
7.A brush assembly as claimed in any one of the preceding Claims
wherein the conductor and the metal wire braid are made of
material of high electrical conductivity.
8, A brush assembly as claimed in Claim 5 wherein the conductor
and the metal wire braid are made of copper.

9. A brush assembly for an electrical machine substantially as herein described with reference to, and as illustrated in, the