Improvements in Commutator Brush Holders for Dynamo Electric Machines or Electric Motors.
Year: 1896

page_text: Date of Application, 22nd Aug., 1896-Accepted, 3rd Oct., 1896
COMPLETE SPECIFICATION.
[Communicated from abroad by ROBERT LUNDELL, of Brooklyn, in the
County of Kings and State of New York, United States of America,
Electrician.]
Improvements in Commutator Brush Holders for Dynamo Electric
Machines or Electric Motors.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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 commutator brush holders for dynamo electric machines
or electric motors.
In certain brush holding devices as heretofore constructed there has been
arranged a yielding spring adapted to feed the brush forward as it is worn away
but with brush holders of such form, "chattering" often occurs, more particularly
when the commutator is running in a reverse direction. Moreover with such
brush holders, it has not been possible to render the pressure constant with different
lengths of brushes.
Now the present invention has for its objects :-First, the construction of a brush
holding and adjusting device which will prevent chattering of the brushes when
the machine is running; secondly, the construction of a brush holding device
which will be adapted to give substantially constant pressure of the brush upon the
commutator for varying lengths of said brush as it wears away; thirdly, the
arrangement and adaptation of such a brush holding device for use with equal
facility. whether the commutator be rotated in one direction or the other; and
fourthly, the adaptation of a brush holder for brushes of different thickness and
length.
In order that the invention may be clearly understood and readily carried into
effect I will proceed to describe the same with reference to the accompanying
drawing in which :-
Figure 1 is a plan view of the improved brush holder.
Figure 2 is a longitudinal sectional view taken through Figure 1 on the
line 2-2, and as seen when looking at that figure from the bottom toward the top
of the drawing in the direction of the arrows, an imaginary commutator being
also shown rotating from right to left.
Figure 3 is a side elevation as seen when looking at Figure 1 from the left
hand toward the right hand side of the drawing, the adjusting devices being
removed:
Figure 4 is a longitudinal sectional view of Figure 1 on the line 4-4, and as
seen when looking at that figure from the bottom toward the top of the drawing,
this figure also indicating an imaginary commutator rotating in the reverse
direction to that shown in Figure I and furthermore indicating a diagrammatic
view of the forces acting upon the brush. when the machine is in motion.
Hrepresents a brush holding device adapted to sustain in a rectangular guide-
way. a carbon brush B with its lower end resting upon a commutator C, ³ being
the rectangular shaped shank of the brush holder provided with the usual
shoulder and screw-threaded neck for securing the said holder to the brush
rookers in a well known manner. His a laterally extending yoke integral with

page_text: the brush holding part H' and provided at its rear end with an upwardly extending
portion H which has in turn a vertical slot 4, said parts being adapted to secure
the adjustable parts of the improved brush holder.
A is an L-shaped metallic part having sufficient bearing against the inner face
and top portion of the brush B to hold it firmly in position in the rectangular
guideway of the stationary part H. This part A is provided with lugs or ears a to
which is pivoted, by a pin and an extension d, a cylindrical part D adapted to
sustain by a shoulder d', one end of a spiral spring S, d being a cylindrical neck
adapted to move. freely within the inner surface e of a second pivoted portion E,
secured by a pin e, extension el and lugs or ears g to an adjustable arm G having
a rectangular shaped extension 9 which is adapted to move vertically in the
rectangular slot of the portion H. The outer surface of the second pivote!
portion E is screw-threaded' and adapted to receive an adjusting nut F provided
with a shoulder for hearing adjustably against the free end of the spring S. to is a
split washer and T a screw-threaded adjusting nut adapted to secure the adjustable
arm G at any desired height in the slot.h, gs being a split pin in the outer end of
the screw threaded extension g' g for preventing the absolute removal of the
nut T.
The operation of the improved brush holder is as follows:-The brus Bis
slipped in place in the rectangular guideway of the holder II and the L-shaped
adjustable holding device A is placed in the position shown in Figures 1, 2 and 4.
The adjustable arm G is then pressed downward until the pressure of the parts
gives to the brush the desired firmness against the inner face of the holder Hand
downward pressure against the commutator C. The nut T is then screwed firmly
home against the split washer w and the apparatus is ready for use. Should it be
desirable at any time, owing to the wear of the brush upon the commutator, to
give a further advancement to the holding device, the nut. F is simply turned to
the right so ns. to. cause the spring S to act with the required pressure upon
the. movable part .E,, and hence through the pivotal part upon the adjustable
holder A.,
Should further advancement of the holding device be required owing to the
wearing away of the lower end of the brush B, it only necessary to release the
set screw. Tand. give to, the adjustable arm Ga downward movement so as to
maintain the angular position of all of the adjustable parts in the relation fixed
upon at the first setting of said parts, after which the nut T is firmly secured as
before. It will be seen that through this double adjustment of the parts GTE F
and D A, it is, possible to give to brushes of varying lengths & pressure upon
the commutator which is substantially constant and at the same time to avoid
any possibility of chattering.
In Figure 4 the operation, of the device is shewnunder the contingency of a
rotation, of the commutator in a reverse direction from that shown in Figure 2, it
being apparent from the parallelogram of, forces illustrated by the letters and y
and the, normal frictional force due.to the action. of the commutator indicated at 2,
that the brush B can never leave the inner surface of the stationary holding
part H' thereby avoiding any possibility of chattering, and also avoiding the evil
effects of raised commutator bars. With this improved brush holding device, it is
possible to utilize brushes of variable thickness and to enable such brushes to be
used, with substantially constant, pressure..upon the commutator and without any
chattering whatever, no matter in which direction, said conmutator may be
rotating.
The improved holding device: may also be used in aur place where it is desired
to conduct, electricity from, a stationary, to a moving, conductor and vice versa..
Having now particularly described and ascertained' the nature of" the said' inven-
tion and in what manner the same is to be performed; as communicated to me
by my foreign correspondent; I declare that what I claim is :-
1. A commutator brush. holder: provided with means for giving to the brush

page_text: continuous pressure against the stationary part of the holder and also against the
commutator, for the purpose specified.
2. A commutator brush holder provided with means for giving to the brush
substantially constant pressure in two directions irrespective of the length of the
brush, substantially as described.
3. A commutator brush holder provided with two sets of adjusting devices, one
of which tends to give to the brush downward pressure against the commutator.
and lateral or side pressure against the stationary part of the holder, and the other
gives to all of said parts vertical adjustment so as to adapt the entire structure for
use with brushes of various lengths, substantially as described.
4. A commutator brush holder provided with a stationary guideway for the
brush and' a movable part which is adapted to bear against the brush in two
directions, and is pivotally secured to an adjustable device, which is mechanically
connected with the stationary part of the holder, substantially as described.
5. A commutator brush holder consisting of a stationary part and a movable
part adapted to exert a pressure upon the brush in two directions, in combination
with adjustable means connecting the movable part with the stationary part whereby
the pressure may be varied as desired, substantially as described.
6. A commutator brush bolder consisting of a stationary part provided with a
guideway for the brush, a movable part pivotally connected to spring-actuated
adjusting mechanism, which is in turn secured to the stationary part, all of these
parte being so arranged that the adjusting mechanism tends to give movement to
the brush in two directions, substantially as described.
7. A commutator brush holder consisting of a stationary part provided with a
guideway for the brush, a movable part adapted to bear against the brush in two
directions and pivotally secured to a spring actuated adjusting device which in turn
is pivotally secured to a second adjusting device having mechanical connection
with the stationary part of the holder, substantially as described.
Dated this 22nd day of August 1896.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant..