Improvements in Carbon Contacts or Commutator Brushes.
Year: 1889

page_text: Cert on Apr., 1009-Accepted, in Jan., 1890
COMPLETE SPECIFICATION.
Improvements in Carbon Contacts or Commutator Brushes.
I, CHARLES JOSEPH VAN DEPOELE of Lynn in the County of Essex, State of
Massachusetts, United States of America Electrician 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 :-
L
The present invention relates to improvements in commutator brushes or contacts
for use with dynamo-electric generators and electro-dynamic motors.
In the operation of electric motors it is desirable for various reasons to use a thick brush
or contact held by suitable mechanism in position tangential to the surface of the
commutator-that is, projected endwise against it. In these positions the brushes may
be moved around the commutator to any desired position without in the least affecting
their mechanical relationship thereto, and it has been usual to use thick bunches of
thin copper laminae secured together at their outer ends for this purpose; but I find
in practice that the leaves of brushes so constructed will get into the interstices or
separations between the sections of the commutator, by the rotation of which the
leaves of which the brush is composed will be gradually bent outward and away from
each other, and so in a short time rendered useless. This difficulty I have overcome
by substituting for the copper contact brushes heretofore used brushes or contacts of
carbon or other non-homogeneous substance, which, being porous, will in a short time
take up a quantity of copper-dust and form a smooth wearing-face that is extremely
durable.
In the accompanying drawings I have shown the practical application of my
invention, which will now be described.
Figure 1 is an elevation of the commutator and brusn-holding devices, together
with the immediately-surrounding parts of an electric motor. Fig. 2 is a sectional
elevation showing the commutator, the armature-shaft, the comniutator-brush-con-
trolling devices, and carbon commutator-brushes in position therein. Fig. 3 is a view
similar to Fig. 1, and shows the application of my present invention to the
commutator brush controlling and adjusting devices now in use. Fig. is a vertical
section on the line 4, 4, of Fig. 3.
Similar letters denote like parts throughout.
My improved brushes consist of plates or pieces of carbon shaped to fit loosely
within the boxes or holders where they are placed, and then securely held in position
gainst the commutator by the tension of suitable springs, to be referred to. The
carbon brushes or contacts A, may be of any desirable length or shape, according to
ircumstances, the particular shape and size or proportion herein shown being merely
or the sake of illustration. The lower ends of the brushes should he formed or
noulded to fit the surface of the commutator, the subsequent wear being sufficient to
etain the shape originally given.
To a hand lever A', journalled so as to be movable radially with respect to the
rmature shaft B, are secured a pair of oblong flat boxes C, which are, arranged
angential to the commutator D, and provided with plungers or followers d, fitting
to the said boxes C, and pressed upon by adjusting screws E, working through the
nds of the boxes C, where they are secured by jam-nuts e. From the sides of the

page_text: boxes C, project at right angles flat springs F, which are securely connected thereto.
The free ends of said springs fit into slots f. formed in posts G, which are pivotally
mounted in the hand lever A', and suitably insulated therefrom. The posts G, are
each provided with a clamping screw g, by which the springs F, are removably secured
in position. The posts G, are placed in diametrically opposite positions with respect
to the commutator. From each of the posts G, on the same side of the commutator,
projects an arm H, which arms are united by a link or connecting rod 1. From the
upper post G, also projects a hand lever K, which may be in itself resilient, or is
provided with a spring latch arranged to engage with one or other of the notches in
the quadrant L, attached to the lever A¹.
With this construction it will be seen that by moving the lever K, in the direction
of the arrow the brushes will be moved from the commutator-a very important
saving of wear and tear when, as is frequently the case in electric railways, long
downgrades have to be traversed, during the descent of which the motor is perforining
no useful work. By a simple return movement of the lever K, the brushes are
again brought into working position without their relative positions having been in
any way altered. The brushes are moved about the commutator by means of the
lever A.
In order to secure great nicety of adjustment of the pressure of the brushes upon
the commutator, the teeth or notches on the quadrant L, should be quite small; or,
instead of teeth, an adjusting screw may be used, the result attained being practically
the same.
In Figs. 3 and 4.I have shown the application of my present improvement to the
commutator brush-bolding devices as constructed for use with brushes formed of
copper laminae, and substantially as set forth in Letters Patent No. 291,650, granted
to me January 8, 1884.
For the sake of clearness I will briefly describe what is shown in said figures. To
the lever A', are rigidly secured flat boxes C. The tops of these boxes are open and
the followers therein are pressed upon by endwise-acting screws E, provided with
jam-nuts e, as previously described. To the jam-nuts e, however, are secured
extensions or ears e', to which are attached tension-springs M, by which the adjusting
screws and followers are constantly pressed against the brushes contained within the
boxes C. With this construction the brushes are constantly in contact with the
commutator, and are only movable around the periphery thereof.
In order to reduce the resistance of the carbon brush to the minimum, the
boxes C, C are brought down very close to the surface of the commutator, and
should the small resistance then remaining be a disadvantage the brushes themselves
can be plated with a good conductor, and all objections thus removed.
1 do not limit myself to the use of carbon alone, as any non-homogeneous or. porous
bard conducting substance will answer the purpose and come within the scope of my
invention.
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. The combination with a sectional commutator, of commutator brushes bearing|
upon the surface thereof and formed of carbon or other similar unyielding material.
2. The combination, with a commutator-cylinder. formed of separated insulated
segments, of cominutator-brushes bearing upon the surfaces thereof and formed of
carbon or other similar unyielding material, and of a width greater than the distances
between the commutator-segments, substantially as described.
3. The combination, with an electro dynamic machine, of commutator brush boxes
and movable supports therefor, carbon coinmutator brushes free to move within said
boxes, adjustable spring actuated forms for pressing the carbon brushes against said
commutator, substantially as described.
4. The combination, with an electro dynamic machine of commutator. brush-boxes
and radially moving support therefor, carbon commutator brushes free to move within

page_text: said boxes and a follower or followers for pressing the carbon brushes against the
commutator, substantially as described.
5. The combination, with a commutator of an electro-dynamic machine, of com-
mutator brush boxes arranged radially with respect thereto, circumferentially moving
supports therefor, resilient arms connecting the brush-boxes and their supports, and
a link connecting said supports, whereby they may be rotated simultaneously in
opposite directions and the brushes moved away from or toward the commutator,
substantially as described.
6. The combination, with an electro-dynamic-machine, of commutator brush-boxes,
resilient arms attached to and extending from said boxes and being longitudinally
adjustable in pivoted supports, connections between the said pivoted supports, whereby
the said supports may be rotated simultaneously in opposite directions, and the brush
boxes moved away from or toward the commutator, and a hand lever connected to
one of the pivotal supports, having a spring-detent, whereby the pressure of the
brush-boxes upon the commutator cylinder may be increased or diminished as desired,
substantially as described.
7. The combination, with an electro dynamic motor and the commutator cylinder
thereof, of an arn pivoted radially with respect thereto, rotating supports upon said
arm, resilient arms projecting therethrough and longitudinally adjustable in said
supports, commutator brush boxes secured to the ends of said resilient arms, a link
uniting said rotating supports, and a hand lever secured to one of said supports,
whereby the same may be rotated simultaneously in opposite directions and the
brush boxes moved away from or toward the commutator cylinder, substantially as
described.
Sixned at Washindan Da TT A
T
1
C
1. 1000
CHARLES JOSEPH VAN DEPOELE.
Wm. P. Thompson & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.