Improvements in Commutator Brushes and Brush Holders.
Year: 1896

page_text: Date of Application, 9th Apr., 1896-Accepted, 6th June, 1896
COMPLETE SPECIFICATION.
Improvements in Commutator Brushes and Brush Holders.
We, ROBERT HIRSCH, MARIA ROSAMUNDE HIRSCH and JAMES FRANKLIN
TROTTMAN, all of 440 National Avenue, Milwaukee, in the County of Milwaukee,
and State of Wisconsin, United States of 'America, Manufacturers, 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 commutator brushes, and brush holders
for use in 'connection with the same.".
In the accompanying drawings-
Figure 1 is a vertical sectional view showing parts in elevation of our improved
commutator brush holder,' and brush.
Figure 2 is a perspective view of the brush.
+
The brush consists primarily of one or more sheets or films of metal which
are repeatedly corrugated, bent or folded, and pressed together to a greater or less
degree so as to form a block of the desired shape, the interstices between the
folds or corrugations of said sheet or sheets being filled with a suitable lubricating
material, and the whole being bound together by an exterior coating or film of
metal.
.....
.
We may employ any one of several methods, in the construction of the brush.
In the particular form of construction shown in the drawings, the brush comprises
three sheets or films of metal, as A, A1 and A2; corrugated or folded as before
described, and pressed together in such a manner as to leave interstices of varying
width for the reception of the filling. A filling B of a suitable lubricating material
or combined lubricating and scouring material, is forced into said interstices, so as
to form, together with the 'sheet or sheets of metal, a solid block, and an exterior
coating C of metal is secured in any desired manner, as by means of the well-known
electro-plating process, upon the outside of the brush.
By means of the described filling of lubricating material, the brush is lubricated
continuously throughout the entire period of the operation of the dynamo or motor
to which it may be applied, and the wear upon the commutator as well as upon
the brush itself, is thereby reduced to a minimum. By the addition of the scouring
material to the filling compound, said, filling serves not only to lubricate the brush,
but serves further to scour and keep the commutator clean and bright during the
entire period of its operation.
"
The metal sheet or sheets which enter into the formation of the brush, afford
ample carrying capacity for the current, and the exterior coating or covering C
of metal serves to afford a perfect metallic contact between the brush and its
holder.
.
By the arrangement of the corrugations or folds of the metal sheets so as to
afford interstices of variable width, the amount of lubricating or combined lubricating
and scouring material contained in one part of the brush is rendered considerably
greater than that contained in the other part of the brush, and the conductivity of
the portion of the brush having the lesser proportion of lubricating or combined
lul.ricating and scouring material is rendered considerably greater than that of the
other part of the brush.
.
In practice, the brush is applied to the commutator so that the side of the
brush having the greatest conductivity is brought last into contact with the

page_text: commutator sections, and it follows therefore, that at the point where contact with
the commutator sections is broken, and where sparking commonly occurs, the
greatest degree of conductivity is afforded, and the liability of sparking is very
greatly reduced.
Our improved brush therefore combines the desirable properties which enable it
to be entirely self-lubricating, and at the same time, capable of keeping the com-
mutator constantly clean and bright, and furthermore to present its greatest
conductivity at the point where contact with the commutator sections is broken,
and to thereby effectually prevent sparking and consequent destruction of the
commutator sections, and of the brush itself.
We have found in practice, that our improved brush is exceedingly durable and
very satisfactory for use upon dynamos and motors of all descriptions, and that by
its use, a very great saving in wear and tear upon the commutators is effected.
We will now describe the brush holder which is designed for use in conjunction
with our improved brush.
The brush holder comprises a suitable supporting plate D, upon which the
brush is arranged to rest, and with which said brush is held in electrical contact as
shown in Figure 1. The plate D is secured to the usual support E for the brush
holder, which is present upon all dynamos and motors, and is conveniently made
adjustable through the medium of a supporting block F, having a flat grooved
extension F upon which the plate D rests, said plate being provided with a
dovetail tenon D' arranged to slide within the groove in said extension F, and
the two parts being secured together by means of a clamping plate G, having a
dovetail groove to fit the tenon D', and provided with a screw-threaded shank g¹
extending outward through a washer H, and engaged with a locking nut Hi
as shown. It will be seen that by this construction, the plate D may be adjusted
toward or away from the commutator as desired, by simply loosening the nut H¹
and sliding said plate D upon the extension F1 and then tightening the nut H'.
Suitable means is provided upon the holder for automatically pressing the brush
toward and into contact with the commutator, and for this purpose we employ an
arm or plate I pivoted as at i, upon the plate D, and provided with a pivoted
push-bar J for engagement with the rear end of the brush. Adjacent to the pivotal
connection of said bar or arm, is provided a suitable spring J1 for normally
pressing the free end of said arm downward or toward the surface of the plate D.
A spring K is operatively engaged with the plate D and the arm or plate I, and
acts against the latter to force the pivoted arm J and the brush engaged there with,
toward the commutator. A suitable number of projections or shoulders K¹ are
provided upon the arm or plate I, for engagement with the free end of the
spring K, so as to vary the tension or pres-ure of said spring, in an obvious
manner, and by this means said spring may be readily adjusted so as to press
the brush against the surface of the commutator with any desired pressure or
force.
As a further improvement, we prefer to provide upon the rear end of the brush,
a suitable projection L, conveniently having one or more up-turned flanges or
lips L', for engagement with the push-bar or arm J, in the manner shown, and it
follows that by this construction, the brush may not only be advanced toward the
commutator by the pressure of the spring, but when desired, it may also be retracted
and held out of contact with the commutator by a backward movement of the
arm or plate 1, and its connected push-bar or arm J. In order to hold said arms
and the brush in their adjusted positions, we conveniently employ a latch M
actuated by a spring m, and arranged to engage with a shoulder or stop M in or
upon the arm J. By this means, the operator may readily retract the arms I and J
together with the brush, when the spring m will automatically engage the latch M
with said stop, and lock the parts in their retracted positions until such time
as the operator may release the latch and allow the parts to resume their normal
positions.
We have found in practice, that this form of brush holder is exceedingly well

page_text: adapted for use in connection with our improved brush, and that by its use a very
satisfactory operation of said brush is ensured, and the life of the brush itself, is
materially prolonged.
In the construction of the brush itself, the brush block may be made up
either from plain sheets or films of metal with the filling pressed or forced
between the corrugations or folds thereof, or the shect itself may be made
composite and may contain alternate layers or films of metal and the described
lubricating or combined lubricating and scouring materials, but in any case, the
result obtained is the same.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. A commutator brush comprising one or more metallic sheets or filins
corrugated, bent or folded so as to form a block of the desired shape and
proportions, and having a filling of lubricating material located in the interstices
between said corrugations.
2. A commutator brush comprising one or more metallic sheets or films
corrugated, bent, or folded to form a block of the desired shape and proportions,
and having a filling of lubricating or combined lubricating and scouring material
located in the interstices of said corrugations, and a covering or sheath of metal
secured to the outside of the block and in electrical connection with the edges
of said corrugations.
3. A commutator brush formed from a composite sheet consisting of alternate
sheets or films of metal, and lubricating, or combined lubricating and scouring
material, and bent, folded, or corrugated to form a block of desired shape and
proportions, and provided with an exterior coating or covering of metal.
4. The combination with a brush holder provided with a spring-controlled
push-bar or arm, of a commutator brush provided upon its rear end with a projecting
lip or flange for engagement with said push-bar or arm.
5. A commutator brush comprising a plurality of sheets or films of metal
corrugated, bent, or folded and pressed together so as to form interstices between
the folds or corrugations, of varying width, and a filling of lubricating or combined
lubricating and scouring material located in said interstices.
6. A brush holder comprising a suitable support, a plate adjustable thereon
and having one face arranged for contact with one side of the brush, a spring-
controlled plate or arm pivotally connected with said adjustable plate, and a
pivoted push-bar or arm operatively engaged with the first mentioned arm or
plate and adapted to bear at its free end against the rear end of the commutator
brush.
Dated thie 28th day of March 1896
ROBERT HIRSCH.
MARIA ROSAMUNDE HIRSCH.
JAMES FRANKLIN TROTTMAN.
Haseltine, Lake & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicants.