IMPROVEMENTS IN DYNAMO OR MAGNETO ELECTRIC MACHINES AND ELECTRIC MOTORS
Year: 1880

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME WE THE EDISON
ELECTRIC LIGHT COMPANY of London Limited send greeting
WHEREAS Her most Excellent Majesty Queen Victoria by Her Royal Letters
Patent under the Great Seal of Great Britain and Ireland bearing date at Westminster
the Fifth day of April in the year of our Lord One thousand eight hundred and
eighty in the Forty third year of Her Reign did for Herself Her hoirs and
successors give and grant unto Thomas Alva Edison of Menlo Park in the State of
New Jersey United States of America his executors administrators and assigns
especial license full power sole privilege and authority that he the said Thomas
Alva Edison his executors administrators or assigns and every of them by himself
and themselves or by his and their deputy or deputies servants or agents or such
others as he his executors administrators or assigns should at any time agree with
and no others from time to time and at all times thereafter during the term
therein expressed should and lawfully might make use exercise and vend within
the United Kingdom of Great Britain and Ireland the Channel Islands and Islo
of Man an Invention of "IMPROVEMENTS IN DYNAMO OR MAGNETO ELECTRIC
MACHINES AND ELECTRIC MOTORS" for and during the term of fourteen years
thence next ensuing And whereas in pursuance and performance of a proviso in
the said Letters Patent contained the said Thomas Alva Edison did within six
calendar months next after the date of the said Letters Patent cause a Specification
in writing under his hand and seal purporting to particularly describe the nature
of the said Invention and in what manner the same was to be performed to be
duly filed in the Great Seal Patent Office And whereas by Indenture bearing
date the Sixth April One thousand eight hundred and eighty two and made
between the said Thomas Alva Edison of the first part Edward Griffith Brewer of
Drexel I
the second part Peter Jensen of the third part Anthony I
Pierpoint Morgan Egisto Paolo Fabbri and I Hood Wright of the fourth

page_text: part Egisto Paolo Fabbri and Grosvenor Porter Lowry of the fifth part, and The
Edison Electric Light Company Limited of the sixth part the said Thomas Alva
Edison as beneficial owner with the concurrence and by the direction of the said
parties thereto of the fourth and fifth parts as beneficial owners granted and
assigned and the said parties thereto of the fourth and fifth parts as beneficial
owners assigned and confirmed to the Company their successors and assigns
absolutely the said hereinbefore recited Letters Patent and the full and exclusive
benefits and advantages thereof And whereas since the date of the said assignment
we have been advised that the matter comprised in the body of the Specification
and claimed under Claims Two to Ten both inclusive is of doubtful novelty or
doubtful utility We therefore disclain the whole of the said Specification except
so much thereof as relates to the rotating armature of dynaino or magneto electric
machines and electric motors and claimed by the First Claim of the said Specification
NOW KNOW YE that We the said Edison Electric Light Company of London
Limited by and with the leave of Her Majesty's Attorney General and for the
reasons aforesaid Do alter and amend the said Specification in manner following
that is to say: We strike out of the Specification printed by the Queens Printers
and published at the Great Seal Patent Office in One thousand eight hundred
and eighty two the words "a portion of" which occur in line 7 of page 4
and insert after the word "armature" in the same line of the same page the word
"of" And we strike out the words "the arrangement of the commutator brushes
or contacts and the shaft of the rotating armature and commutator which are
applicable to both" which occur in lines 7, 8 and 9 of same page and we strike out
the word "to" which is the last word in line 9 of the same page And we strike
out the whole of the said Specification from the word "commutator" in line 33 of
page 4 to the words "the other" in line 51 of page 7 And we strike out the
word "First" which occurs in line 53 of page 7 We also strike out the whole of
the Second, Third, Fourth, Fifth, Sixth, Seventh, Eighth, Ninth and Tenth Claims of
in line 56 of
the said Specification which commence with the word "Second"
page 7 and end with the words "as set forth" in line 20 of pago 8 And in order
that the effect of the Disclaimer and Memorandum of Alteration as aforesaid may
be clearly understood We annex horeto a copy of the said Specification as it will
appear when so altered and amended the preamble and testing clause being
omitted:
My Invention relates to the rotating armature of dynamo or magneto electric
machines and electric motors.
In rotating armatures made of a solid mass of metal or of several large rings of
metal, currents are induced in the armature itself which circulato from points of
greatest to those of lowest potential.
To such currents is largely due the heating of the armature so often present as
an injurious element in such armatures.
To remedy this I construct an armature of a number of very thin disks or rings
secured together upon a proper shaft or base and slightly insulated from each
other. I have found that very good results are attained by using disks or rings
one thirty second to one sixty fourth of an inch thick separated from each other
by sheets of tissue paper. As currents induced in the rotating armature have very
small electro-motive force, the insulation of the tissue paper and the thinness of
the plates prevent almost, if not quite, entirely the circulation of induced currents
and the beating attendant thereon. By this the effective capacity of the machine for
conversion is very largely increased, for while the heating at one moment is not large,
the covering of the armature prevents radiation and the accumulation of beat
proceeds faster than its dissipation and the armature becomes an accumulating
receiver of heat until the capacity of the machine for conversion is much impaired
by limitation of exterior energy due to this heating, all of which is obviated by
this use of exceedingly thiu plates or disks. In this connection, as the word thin is
a relative one,
it is well to state that the plates should be at most not more than

page_text: an eighth of an inch thick, and preferably very much thinner and insulated from
each other in order to attain these effects.
What I claim is :-'
A rotating armature composed of thin metal plates disks or rings as described
with alternating interposed insulating material secured together upon a shaft or
hub, substantially as set forth.
In witness whereof The Edison Electric Light Company of London Limited
have caused their common seal to be hereunto affixed the Second day of
June One thousand eight hundred and eighty two.
ANSON
hereby grant my Fiat giving leave to the Edison Electric Light Company
Limited, as Assignees of the said Letters Patent, to file in the Office of the Com-
missioners of Patents for Inventions, with the Specification to which the same
relates the above written Disclaimer and Memorandum of Alteration.
Dated this thirtieth day of June One thousand eight hundred and eighty two.
HENRY JAMES,

page_text: LETTERS PATENT to Thomas Alva Edison, of Menlo Park, in the State of New
Jersey, United States of America, for an Invontion of "IMPROVEMENTS IN
DYNAMO OR MAGNETO ELECTRIC MACHINES AND ELECTRIC MOTORS."
PROVISIONAL SPECIFICATION left by the said Thomas Alva Edison at the
Office of the Commissioners of Patents on the 5th April 1880.
E
THOMAS ALVA EDISON, of Menlo Park, in the State of New Jersey, United States
of America. IMPROVEMENTS IN DYNAMO OR MAGNETO ELECTRIC MACHINES
AND ELECTRIC MOTORS,'
A portion of my Invention relates to the rotating armatures, the arrangement of
the commutator brushes or contacts, and the shaft of the rotating armature and
commutator, which are applicable to both dynamo or magneto electric machines
and to electric inotors.
In rotating armatures made of a solid mass of metal, or of several large rings of
metal, currents are induced in the armature itself, which circulate from points of
greatest to those of lowest potential.
To such currents is largely due the heating of the armature so often present as
an injurious element in such armatures.
To remedy this I construct an armature of a number of very thin discs or rings
secured together upon a proper shaft or base, and slightly insulated from each other.
I have found that very good results are attained by using discs or rings, one thirty
second to one sixty fourth of an inch thick, separated from each other by sheets of
tissue paper. As currents induced in the rotating armature have very small electro
motive force, the insulation of the tissue paper and the thinness of the plates prevent
almost, if not quite, entirely the circulation of induced currents and the heating
attendant thereon. By this the effective capacity of the machine for conversion is
very largely increased, for while the heating at one moment is not large the covering
of the armature prevents radiation, and the accumulation of heat proceeds faster
than its dissipation, and the armature becomes an accumulating receiver of heat
until the capacity of the machine for conversion is much impaired by limitation of
exterior energy due to this heating, all of which is obviated by this use of
exceedingly thin plates or discs. In this connection, as the word thin is a relative
one, it is well to state that the plates should be at most not more than an eight of

page_text: an inch thick, and preferably very much thinner and insulated from each other in
order to attain these effects.
Commutator springs or brushes have always been arranged at right angles to the
axis of the commutator.
With such thero has usually been a large amount of "spark" on the face of the
commutator indicating a loss of electric energy by its conversion at a point where
conversion was not only unneeded, but injurious, causing a rapid destruction of the
commutator apparatus. I find that this can be largely and usually entirely avoided
by arranging the commutator springs or brushes so that their axial line is at an
angle other than a right angle with the axis of the commutators, or in other words,
that the brushes or springs bear obliquely upon the face of the commutator.
In practice I have found that it is better that the brushes or springs stand at an
angle of about 30° to the axis of the commutator.
As ordinarily arranged the brushes or springs travel over the face of the com-
mutator in a uniform track speedily wearing a groove therein, rendering the face of
the commutator uneven.
To remedy this, insuring even wear over the whole surface of the commutator,
and also to insure even wear and polishing of the surface of the revolving armature,
I arrange the shaft of the commutator and its bearings so that the shaft may have
a longitudinal movement in the bearings. Upon the outer end of the shaft a disc
is fixed forming a circular armature to an electro magnet suitably attached to the
frame of the machine. When this magnet is charged, attracting the armature, the
shaft is moved in one direction to its limit of motion, a spring serving to force it to
the other limit when the magnet is inactive.
If an iron pulley be used upon the shaft of the armature and commutator and
placed near the polar extension of the field magnets the spring may be dispensed
with, the magnet for moving the shaft being placed to move the shaft in one
direction, the attraction between the machine magnets and the pulley serving to
move the shaft in the other direction. Attached to any rotating part of the
apparatus is a disc, a portion of whose periphery is of insulating inaterial, the
remainder being a conductor, or the disc may have several alternating conducting
and non-conducting portions. Upon the disc bears a contact spring, the disc and
spring being interposed in a circuit leading from a battery or other source of
electricity to the magnet last spoken of, or the current therefor through a shunt
may be a portion of the machine itself, one rotating disc and spring may be arranged
to control the circuit of the shaft moving magnets of a large number of machines or
motors.
In providing electro motors for any given work it is desirable that any one
motor should be constructed to give the maximum power required with a certain
definite current.
As is the case with all motors, however, it may be desired to use the motor for
less than its maximum capacity, that is to run it with a variable load or amount
of work to be performed, it is preferable that it should be provided with a
governor to correct any fluctuations in speed consequent upon such variation in
load or work.
To accomplish this I place on the main shaft, or I gear to it either directly or
by belting, a centrifugal governor which lifts upon too great speed, an adjustable
circuit lever controlling by either making or breaking directly or indirectly the
circuit to the motor; this lever may control directly the circuit to the motor
passing through it, or it may control indirectly by controlling a local battery
circuit to a magnet, whose armature lever operates a circuit breaker placed in the
motor circuit. In order to prevent too sudden fluctuations upon the breakage of
circuit, and to maintain regularity while the current is on, the main shaft is
provided with a heavy fly or balance wheel, whose momentum prevents irregularities
and causes gradual slowing down when the circuit is broken. As the circuit
controlling lever of the governor completes the circuit through an adjustable stop,
the joint effects of the governor and Hy wheel are that the machine is capable of

page_text: the finest adjustment, breaking and completing the circuit upon the least
variation from a determined desired speed acting exactly, so to speak, as an
automatic cut off in steam engines, preventing unnecessary consumption of
energy.
The breaking of the main circuit occasions a large spark at the breaking point,
which is more destructive as a unit than it would be if divided into several sparks,
hence I break the main circuit when breakage is necessary at several points
simultaneously, in order to divide the spark and lessen its total injurious effect.
I accomplish this by fixing upon an insulating base several contact springs, the
free ends of which rest each respectively upon proper contact posts, and project
slightly beyond the same. The circuit is led to one post, passes to its spring
whence it passes by a wire to the next post into its spring by wire to next post,
and so on through the series of springs and posts. Either the circuit controlling
lever or the armature lever, as either is used for the purpose as before explained, is
broadened at the end, so as to take under the extreine free ends of all the circuit
springs, and upon desired movement lift them from their posts, breaking the main
circuits at a number of points.
In using electric motors, especially for actuating light machinery, it is very
desirable that the rate of speed of the actuated machine be under control of the
operator, and that the means of control be simple, effectual, and easy of application.
Hitherto this has been attempted only through controlling the electric circuit to
the motor, breaking or closing it in whole or in part.
I propose to control the speed by the application of a brake to the main driven
wheel without reference to the current. A brake is so pivoted as to be capable of
bearing upon the wheel, but kept therefrom normally by a spring.
Attached to the brake is a lever which in turn is attached to a treadle, by
means of which any desired pressure may be applied, though it is evident that
the brake lever may be arranged to be operated by hand instead of through the
medium of a treadle.
So far as I am aware electric motors have always been connected direct to the
actuated machine, so that the rate of speed of the actuated machine and of the
motor were the same. It is often desirable that the actuated machine be driven
at a less or at a greater rate of speed than the motor. To effect this I interpose
between the two differential gearing, that is, gearing which may be cogged wheels,
pinion wheels, friction gearing, belts and pulleys, or equivalents of different diameter,
arranging them to produce the desired differential speed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Alva Edison in the Great Seal Patent Office on the 5th
October 1880.
THOMAS ALVA EDISON, of Menlo Park, in the State of New Jersey, United States
of America. "IMPROVEMENTS IN DYNAMO OR MAGNETO-ELECTRIC MACHINES
AND ELECTRIC MOTORS."
A portion of my Invention relates to the rotating armature, the arrangement of the
commutator brushes or contacts and the shaft of the rotating armature and com-
mutator, which are applicable to both dynamo or magneto electric machines and to
electric motors.
In rotating armatures made of a solid mass of metal, or of several large rings of
metal, currents are induced in the armature itself which circulate from points of
greatest to those of lowest potential.
To such currents is largely due the heating of the armature so often present as
an injurious element in such armatures.
To remedy this I construct an armature of a number of very thin disks or rings
secured together upon a proper shaft or baso, and slightly insulated from each
other. I have found that very good results are attained by using disks or rings
one thirty second to one sixty fourth of an inch thick, separated from each other
by sheets of tissue paper. As currents induced in the rotating armature have very
small electro-motive force, the insulation of the tissue paper and the thinness of
the plates prevent almost, if not quite, entirely the circulation of induced currents
and the heating attendant thereon. By this the effective capacity of the machine
for conversion is very largely increased, for while the heating at one moment is not
large, the covering of the armature prevents radiation, and the accumulation of
heat proceeds faster than its dissipation, and the armature becomes an accumulating
receiver of heat until the capacity of the machine for conversion is much impaired by
limitation of exterior energy duo to this heating, all of which is obviated by this
use of exceedingly thin plates or disks. In this connection, as the word "thin" is a
relative one, it is well to state that the plates should be at most not more than an
eighth of an inch thick, and preferably very much thinner and insulated from each
other in order to attain these effects.
Commutator springs or brushes have always been arranged at right angles to the
axis of the commutator. With such there has usually been a large amount of
spark" on the face of the commutator, indicating a loss of electric energy by its
conversion at a point where conversion was not only unneeded but injurious, causing
a rapid destruction of the cominutator apparatus.
I find that this can be largely, and usually entirely, avoided by arranging the
commutator springs or brushes so that their axial line is at an angle other than a
right angle with the axis of the commutators, or in other words, that the brushes or
springs bear obliquely upon the face of the commutator.
In practice I have found that it is better that the brushes or springs stand at an
angle of about 30° to the axis of the commutator. As ordinarily arranged the
brushes or springs travel over the face of the commutator in an uniform track,
speedily wearing a groove therein, rendering the face of the commutator uneven.
To remedy this, ensuring even wear over the whole surface of the commutator,
and also to ensure even wear and polishing of the surface of the revolving armature,
arrange the shaft of the commutator and its bearings so that the shaft may have
a longitudinal movement in the bearings. Upon the outer end of the shaft a disk
is fixed, forming a circular armature to an electro magnet suitably attached to the
frame of the machine. When this magnet is charged, attracting the armature, the
shaft is moved in one direction to its limit of motion, a spring serving to force it
to the other limit when the magnet is inactive.
I

page_text: If an iron pulley be used upon the shaft of the armature and commutator, and
placed near the polar extension of the field magnets, tho spring may be dispensed
with, the magnet for moving the shaft being placed to move the shaft in one
direction, the attraction between the machine magnets and the pulley serving to
move the shaft in the other direction. Attached to any rotating part of tho
apparatus is a disk, a portion of whose periphery is of insulating material, tho
remainder being a conductor; or the disk may have several alternating conducting
and non-conducting portions. Upon the disk beurs a contact spring, the disk and
spring being interposed in a circuit leading from a battery or other source of
electricity to the magnet last spoken of, or the current therefor through a shunt
may be a portion of the machine itself. One rotating disk and spring may bo
arranged to control the circuit of the shaft moving magnets of a large number of
machines or motors.
In providing electro motors for any given work it is desirable that any one
motor should be constructed to give tho maximum power required with a certain
definito current. As is the caso with all motors, however, it may be desired to uso
the motor for less than its maximum capacity, that is, to run it with a variable
load or amount of work to be perforined; it is preferable that it should be provided
with a governor to correct any fluctuations in speed consequent upon such variation
in load or work. To accomplish this I place on the main shaft, or I gear to it,
either directly or by belting, a centrifugal governor which lifts upon too great
speed, an adjustable circuit lever, controling by either making or breaking, directly
or indirectly, the circuit to tho motor. This lever may control directly the circuit
to the motor passing through it, or it may control indirectly, by controling a local
battery circuit to a magnet whose armature lever operates a circuit breaker placed
in the motor circuit. In order to provent too sudden fluctuation upon the breakage
of circuit, and to maintain regularity while the current is on, the main shaft is
provided with a heavy fly or balance wheel whose momentum prevents irregu-
larities, and causes gradual slowing down when the circuit is broken.
circuit controling lever of the governor completes the circuit through an adjustablo
stop, the joint effects of the governor and fly-wheel are that the machine is capable
of the finest adjustment, breaking and completing the circuit upon the least
variation from a determined desired speed, acting exactly, so to speak, as an
automatic cut-off in steam engines, preventing unnecessary consumption of
energy.
As tho
The breaking of the main circuit occasions a large spark at the breaking point,
which is more destructive as a unit than it would be if divided into several sparks,
hence I break the main circuit, when breakage is necessary, at several points
simultaneously in order to divide the spark and lessen its total injurious effect.
I accomplish this by fixing upon an insulating base several contact springs, the
free ends of which rest cach respectively upon proper contact posts, and project
slightly beyond the same. The circuit is led to one post, passes to its spring,
whence it passes by a wire to the next post and its spring, and by wire to the
next post, and so on through the series of springs and posts. Either the circuit
controling lever or the armature lever, as either is used for the purpose as before
explained, is broadened at the end so as to take under the extreme free ends of
all the circuit springs, and upon desired movement lift them from their posts,
breaking the main circuit at a number of points.
In using electro motors, especially for actuating light machinery, it is very
desirable that the rate of speed of the actuated machine be under control of the
operator, and that the means of control be simplc, effectual, and easy of
application.
Hitherto this has been attempted only through controling the electric circuit to
the motor, breaking or closing it in whole or in part. I propose to control the
speed by the application of a brake to the main driven wheel without reference
to the current. A brake is so pivoted as to be capable of bearing upon the wheel,
but kept therefrom normally by a spring. Attached to the brake is a lever which

page_text: in turn is attached to a treadle, by means of which any desired pressure may be
applied, though it is evident that the brake lever may be arranged to be operated
by hand instead of through the medium of a treadle.
So far as I am aware electric motors have always been connected direct to the
actuated machine, so that the rate of speed of the actuated machine and of the
motor were the same. It is often desirable that the actuated machine be driven
at a less or at a greater rate of speed than the motor. To effect this I interpose
between the two differential gearing, that is, gearing which may be cogged wheels,
pinion wheels, friction gearing, belts, and pulleys, etc., of different diameters,
arranging them to produce the desired differentiation of speed.
Referring now to the Drawings for a more particular description,
Fig. 1 is a detailed view of several parts detached from Fig. 2.
"
2 is an isometric view of a machine embodying a portion of the improvements
forming the Invention herein claimed.
Fig. 3 is a plan view.
"
"
4, an end view, and
5 a side view of a motor and actuated machine showing another portion of
the Invention herein claimed.
a is a rotating armature which revolves between polar extensions of magnets not
necessary to be shown. This armature is composed of a number of thin plates,
rings, or disks secured upon the shaft b, thin pieces of insulating material, preferably
tissue, alternating with the plates, rings, or disks, and separating each of them from
all the others. The black lines at a' show the metallic plates, the intermediate white
lines representing the insulating inaterial. The plates, disks, or rings should not
exceed one eighth of an inch in thickness, while the best results are obtained when
the thickness is from one sixty fourth to one thirty second of an inch. d, d, aro the
commutator brushes or springs resting against the commutator d³; these brushes
are secured in stands capable of horizontal and vertical adjustment, as shown.
As more clearly shown in Fig. 1 the springs or brushes are placed obliquely to the
axis of the commutator, preferably at an angle of about 30°. The shaft of the
revolving armature and of the commutator is supported in boxes and is arranged
to have a longitudinal movement therein. Upon the end of the shaft b is fixed a
disk f, which forms the armature for a magnet m; whose poles p, p, are extended,
as shown, to exert their influence upon. Through the magnet passes an electrical
circuit y, y, in which is placed a circuit interrupter, consisting of a spring u whose
free end bears upon a hub or disk t, whose surface is composed of alternate con-
ducting and non conducting material, one or a series of alternations being used.
While the spring u beare on a conducting portion of t the circuit through mis
complete, and the poles p, p, attract f, pulling the shaft b to its limit of movement
in one direction. When the circuit is broken a spring a forces the shaft to its limit
in the opposite direction. The hub or disk t may be attached to any rotating part
of a machine, or it may be driven by an independent motor. If it be so geared
that its rate of speed is different from that of b, the movements of b will not occur
at the same relative time in consecutive rotations, and the wear of the commutator
will be evenly distributed over its whole face, and the rotating armature will also
be evenly worn and polished. I prefer that mica be used as the insulating material
between the metal bars or strips of the commutator. One circuit breaker u, t, may
control the circuit for a number or battery of generators or motors; or a series of
them may be arranged upon one shaft, each controling the circuit to a generator or
to a motor, and arranged to operate in succession.
As before stated if an iron pulley be used upon the shaft b it may be so arranged
that the attraction between it and the not shown magnets of the machine will move
the shaft in one direction, the attraction between f and p, p, moving it in the other,
in which case the spring s is dispensed with.
g is a centrifugal governor connected to the shaft b by a belt q; it is evident
however that this governor may be placed on the shaft, or may be geared directly
thereto. The sliding tube g' of the governor, raised or lowered by the action of

page_text: the governor balls, carries a shoulder h taking under a pivoted lever h', whose free
ond normally rests upon an adjustable stop i. The circuit x, x, of a small battery
LB passes through the lever h¹ and stop i. This circuit x, x, also passes through
an electro magnet ¹ whose arinature lever n is pivoted in suitable standards 1, 2 ;
the free end of this lever n is widened out into a plate which takes under the free
ends of a series of circuit springs, in this case four in number o', o³, o³, o, which
number however may be greater or less, as desired. Those springs are attached to
an insulating support 7', and are arranged when not lifted by n to rest upon contact
posts The motor circuit M C passes to the spring o¹ and post 1", then
by wire to spring of and post r², and so through the series. The lever ¹ and part i
are adjusted so that they shall remain in contact whenever a desired predetermined
speed is not exceeded, but that h' shall be lifted from i when such speed is exceeded.
In this latter event the circuit x, x, is broken between h¹ and i, the magnet is
discharged, the armature lever n is raised by the force of its spring lifting the
springs o¹, o, etc., from their posts, and breaking at each the motor circuit mc.
By this means a motor may be kept in action with a steady speed, and the
destructive effects of one large main circuit spark lessened very materially by
dividing into several minor sparks, or by increasing the number of springs and
contact posts for breaking the main circuit any sensible spark effect may be
entirely obviated.
If desired the battery L B, circuit x, x, and magnet may be dispensed with,
and the springs o¹, o², o³, o, etc., be operated by the lever h'.
Further, several magnets and armatures might be used, one being assigned for
each spring, or for each division of two or more springs of the entire number used.
In addition upon the shaft bis mounted a heavy By or balance wheel F, W, whose
inomentum serves to avoid too sudden fluctuations in speed upon breaking the
circuit.
In Figures 3, 4, and 5 a' is any suitable electro motor in which a' is the rotating
armature, on whose shaft is a commutator d², upon which press the springs or
brushes d, d, for completing the circuit from the conductors 1, 2, to the motor.
Upon the shaft is the pulloy b secured thereto by friction, the friction being so
adjusted that the pulley and shaft shall be held and move together when only tho
resistance of the actuated machine is to bo overcome, but that whenever a greater
resistance is offered the friction shall be overcome and the shaft rotate within the
pulley without rotating it. From the pulley b' a belt 65 leads to the large fly
pulley be secured to the frame of the actuated machine. Upon the shaft of 6ª is
the pulley b7, from which a belt bº transmits the motion to the actuated machine.
Upon the underside of the table e', or to any convenient part of the frame, is
pivoted a brake e³, adapted to be brought to bear upon the pulley 66, but held
normally from so doing by a spring . To the brake e is pivoted the rod eº, which
passos down and is connected with a treadle e' underneath the table.
Through this treadle then any desired pressure may be put upon the periphery
of the wheel 66, regulating its speed, the current to the motor remaining unaffected
and its rotation continued. To the switch s¹ is attached a rods which passes to
the front of the machine within easy reach of the operator. This switch is used to
complete or break the circuit to the motor.
The switch may if desired be placed upon the frame or table of the actuated
machine.
The form of the brake used may be varied; for instance, it may be a belt
tightener, the belt b being normally loose and the brake arranged to tighten it so
that it will take upon the pulleys and transmit motion from one to the other.
What I claim is,―
First. A rotating armature, composed of thin metal plates, disks, or rings, as
described, with alternating interposed insulating material, secured together upon a
shaft or hub, substantially as set forth.
Second. The combination with a commutator of contact brushes or springs,
arranged at an angle to the axis of the commutator, substantially as set forth.

page_text: Third. The combination with the shaft of a commutator or rotating armature, or
both, adapted to have a reciprocating movement in its supporting journals of
means for giving such motion, substantially as set forth.
Fourth. The combination with a rotating shaft of a commutator or armature, or
both, of an arinature, a magnet, and a circuit controling device for giving a recipro-
cating motion to the shaft, substantially as set forth.
Fifth. The combination with a revolving armature of a governor receiving
motion therefrom, and adapted to control tho main circuit, substantially as set
forth.
Sixth. The combination with a revolving armature of a fly or balance wheel,
substantially as set forth.
Seventh. The combination with the main circuit of a circuit breaker, adapted to
break or close the main circuit at several points simultaneously, as set forth.
Eighth. The combination with an electro motor of a brake applied to the main
driven wheel, substantially as set forth.
Ninth. The combination with an electro motor of a friction pulley on the rotating
shaft of the motor, and a brake applied to the main driven wheel and adapted to
control its speed, substantially as set forth.
Tenth. The combination with an electro motor of a mechanical brake adapted
to control the speed of the actuated machine, substantially as set forth.
In witness whereof, I, the said Thomas Alva Edison, have hereunto set my
hand and seal, this Seventeenth day of September, A.D. 1880.
MITOYUN
TIINANY
Witnesses,
TANT T
BET NEATLI
CHA². H. SMITH, 140, Nassau St., New York.
GEO. T. PINCKNEY,
"
"
»
"