Improvements in Brush Holders for Electric Machines.
Year: 1899

page_text: Date of Application, 11th Aug., 1899-Accepted, 16th Sept., 1899
COMPLETE SPECIFICATION.
Improvements in Brush Holders for Electric Machines..
I, SIDNEY HOWE SHORT, of 110, Cannon Street, in the County of London,
Electrical Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:―
This invention relates to improvements in brush holders for electric machines,
and has for its object to improve the adjustment of such holders.
In order that my invention may be clearly understood and readily carried into
effect I will describe the same fully with reference to the accompanying, drawings
which show by way of example a brush holding device particularly designed for
use with street railway motors, although it is capable of a more general applica-
tion, including use on stationary motors.
Figure 1, is a side elevation of the complete brush holder device, as it is applied
to a commutator;
Figure 2, is a vertical central section on the line a a of Figure 1;
Figure 3, is a vertical section on the line, of Figure 1; and
Figure 4, is a top or plan view of an adjusting plate.
In all the figures like letters and numerals refer to the same or similar parts.
One purpose of the construction is to provide an adjustment lengthwise with
the commutator for the whole brush holder so as to centre the brush upon the
wearing surface of the commutator bar, or to place it midway between the com-
mutator lug and the outer end of the commutator bar. Considerable trouble has
been experienced in practice because of the difficulty in adjusting the brush
holders lengthwise with the commutator, in that the brush often over-hung the
end of the commutator and sometimes came so close to the lug of the latter as to
cause the brush holder to strike against such lug.
Another feature of the invention provides an adjustment for the brush holders
proper, that is to say the individual brush holders, radially with the commutator,
so that, as the commutator surface wears down, the brush holder can be adjusted
to follow the wear of the commutator and prevent too much space being left
between the brush holder and the commutator face or surface.
Any desired number of individual brush holders are mounted upon the brush
holder bar A, which bar is made of suitable insulating material, preferably wood.
The bar A, is fastened by bolts 3, or otherwise secured to the lower part B, of
an adjusting bracket, which part is conveniently made of angular shape in cross-
section, and the upper surface of which is serrated or notched as shown at X
(Figure 2). This lower part B, of the adjusting bracket is, in turn, suspended
from the upper part C, of such bracket, which latter, in its turn, is hung from the
frame casting 1, of the motor shell or machine, to which it is attached by means
of cap screws 1. The under side of the upper part C, of the adjusting bracket is
serrated or notched to fit the serrations or notches in the surface of the lower
part of such bracket; and these two parts are clamped together detachably, as, for
instance, by means of cap screws 2, the lower ends of which screw into the lower
part and pass through elongated slots i, formed transversely of this upper plate or

page_text: part C, that is, formed in the direction of the length of the commutator bars; and
while the construction affording this adjustment, as shown and described, is found
convenient and well adapted for the purpose, it is obvious that the details of such
construction may be widely varied without departing from the invention, so long
as the principle of adjustment is effected by the mechanism employed. As before
explained, the object of this adjustment lengthwise of the commutator is to permit
the whole brush holder device, containing all the individual brush holders, to be
placed midway between the commutator lug and the outer end of the commutator
bar.
In addition to the adjustment of the whole brush holding device in the manner
just described, there is also provided a separate adjustment for the individual
brush holders in a radial direction with respect to the commutator, so that as the
commutator surface wears down, each individual brush holder can be adjusted
to follow the wear of the commutator. In order to provide this adjustment, the
construction which will now be described is a convenient one. The bar A, has
secured to it a brush holder plate E, or as many of them as there are brush holders.
The plate E, is provided with a socket, or other means of attachment, for the
conducting cable which is to carry the current to and from the brush holders, said
conducting cable being designated in the drawing by the letter G. Wood
screws W, may be employed to fasten the plates E to the bar A, or they may be
secured to the same in any convenient manner. The socket or holder for the
brush is designated by the letter D, and is provided with a projecting arm Y,
which is serrated on one face. The plate E, is also serrated upon its outer face
as shown at Z, Figure 3, and these two serrated parts are held in engagement in
any suitable manner, as, for instance, by bolts 4, the slots in the projecting part Y,
to permit the passage of the bolts, being elongated as shown in the drawing, for
the purpose of permitting adjustment when the bolts are loosened. This adjust-
ment, as will be seen, is radially of the commutator, and is for the purpose before
described. While the serrated plates and clamping bolts have been found well
adapted for the purpose in practice, and therefore preferable, yet it is obvious
that other means may be utilized for accomplishing this adjustment.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. A brush holding device in which the part carrying the brush holders proper
is adjustable longitudinally with respect to the commutator for the purpose
specified.
2. In a brush holding device a bracket suspended from the frame of the electric
machine and supporting the part carrying the brush holders proper, said bracket
being composed of two portions provided with means for permitting of their
adjustment, substantially as described.
3. The combination with the aforesaid longitudinally adjustable part, of brush
holders proper which are adjustable radially with respect to the commutator for the
purpose specified.
4. A brush holder proper, comprising two portions provided with means for
permitting of their adjustment relatively to each other substantially as described.
5. A brush holding device having its parts constructed, arranged and combined
substantially as herein described with reference to the accompanying drawings
for the purposes specified.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.