IMPROVEMENTS IN ELECTRIC MOTORS
Year: 1885

page_text: COMPLETE SPECIFICATION.
I, CHARLES ALMON JACKSON, of Lawrence, in the County of Essex, State of
Massachusetts, United States of America, Gentleman, do hereby declare the nature
of my invention for "IMPROVEMENTS IN ELECTRIC MOTORS" 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 electric motors and belongs particularly to that class in
which a reciprocating armature is used in connection with a series of coinmutators
and brushes in lieu of employing the revolving armature, as in the ordinary dynamo
machines for generating power.
My invention consists essentially in the peculiar adaptation of a crank to a
driving shaft, whereby an increased length of crank is obtained with but a
minimum traverse or throw of the armature. This travel of the armature has
hitherto been cause for the non-employment of electric motors on the crank
system, since it is well understood that the armature is active, when in close
proximity to the electro-magnets and for that time, while the armature is travelling
over any excessive distance, which may exist between any two magnets, there is
consequently unnecessary loss, and cessation of power during that interval.
Now I obtain this minimum of travel in my invention, which is thus briefly
described by saying that the crank is attached to the shaft, but not to the cross-
head within which it travels, and from which it receives intermittent thrusts; but.
the cross-head is attached directly to the connecting-rod carrying the armature and
its extreme travel or thrust is but slightly more than the length of the radius of
the bore of said cross-head, while the crank, after the thrust given, is free to travel
the length of a radius without carrying the armature with it, thus obviating
unnecessary throw of said armature, and when the crank has travelled 180° the
cross-head again exerts an active thrust in the opposite direction for the length of
a radius. Now in case the latter and its connecting rod were directly attached to
a crank of the same radius, it would be forced to travel with it, and in lieu of
moving only the length of a radius would be obliged to travel through 180° or
twice the radius to reach the same point attained in my method, thus I save the
travel in a great measure and still obtain the crank leverage.
I have therefore endeavored to obviate any excessive travel of the armature by
the relation of the operative parts to be hereafter described. My invention further
consists in the general arrangement of the electro-magnets and their disposition
with respect to the driving shaft, also in the construction and disposal of the
commutators and brushes, whereby proper thrusts are obtained from the armatures
and magnets to rotate the main shaft, and ready means are secured for reversing
the motor at the will of the operator, or stopping it entirely. This arrangement of
the crank permits the thrust or power to be exerted at the time when it is most
effective, that is when said thrust is at right angles to a radius instead of in line
with it.

page_text: ·
The drawings represent in Fig 1 a general plan or diagrammatic view of the
current system, as applied to the electro-magnets and armatures forming part of an
electric-motor embodying my improvements. Fig. 2 represents a horizontal section
of the motor, while Fig. 3 is a vertical transverse section through one of the cross-
heads at the commencement of an active thrust. Fig. 4 shows the position of the
cross-head relatively to the crank during the inactive portion of the revolution of
the latter. Fig. 5 is a modified form of the crank disk. Figs. 6, 7, 8, and 9 are
diagrams to show the position of the various cooperating parts, at the commence-
ment of one quarter of a complete revolution of the main shaft. Fig. 10 is an
isometric view of one of the commutators and Fig. 11, is a section on line xx, of
Fig. 10; Fig. 12 is a vertical cross-section of the standards in which the cross-
heads reciprocate.
In these drawings A A represent two parallel standards or housings forming a
general support for the motor. These standards are constructed with vertical
polygonal openings as a etc V shaped at top and bottom to form ways in which to
support and permit the travel of a series of cross-heads B B etc. tentrally bored at
65 66 and provided with arms c3 c etc. in cross-section similar to the openings a³ aª
in which they reciprocate. To the extremities of these arms are attached the
connecting rods C5, C6, C7, C8, the latter being secured to swinging lever arms d³ do
etc. and suitably disposed in bearings--while to the lower extremities of said levers
are attached the armatures D D. Thus when the current is passed through the
electro-magnets the armatures are influenced and a thrust is imparted to the main
shaft E by means of the operative parts above described.
It will be observed that the openings 6º 66 of, 'the cross-heads are constructed of
considerable diameter and made for the purpose of containing circular disks ees,
which latter revolve within them and are pivoted and secured to said shaft by
means of cranks ƒ ƒ etc. and crank-pins g³ gº etc. Thus the main shaft is
composed of a series of short shafts supported upon and suitably journaled in
a number of posts F F etc.
The electro-magnets are arranged in pairs, as shown at A¹ B³ C¹ D³ E' F¹ G* H³
and similar corresponding pairs at a' b c d e f g h³. In this nomenclature
I have adopted a certain system of lettering to correspond with a continuous
current which is shifted at four different successive intervals of time to act upon a
different set of instrumentalities each time; which latter are operated by the
magnets then rendered effective by the shifting of the current. Thus the exponents
of the letters used in designating said magnets always have the same exponent,
whenever they are employed simultaneously; that is, when the current is employed
to operate the electro-magnet A¹ A¹ it also traverses the electro-magnets C¹ C¹
a a c c at the same time and renders them active likewise. By this system the
parts cooperating with each other simultaneously at any given portion of the
stroke or revolution of the shaft are easily ascertained in the description of
the operation of said machine.
Suitably disposed and fixed upon one end of the shaft É are the commuta-
tors' I J K L adapted by means of their brushes i¹³ to make and break the
circuit at proper intervals of time with respect to the main shaft, by which their
cooperating parts shall actively affect said shaft to maintain it in rotary paths of
movement.
The commutators are four in number, and in the present case are compound for
the purpose of enabling the driving shaft to be reversible in its rotation or be
stopped entirely. For this purpose I have made the commutators compound,
that is each individual one consists of three disks, two outside or exterior ones
marked o o. and the dividing disk p, composed entirely of insulating material.
The disks o³ of are similarly shaped, but have three quarters of their peripheries of
insulating material m m, while the other quarters n n are of metal and adapted to
effect metallic contact with each brush at proper times. Furthermore the disk o³
upon one side of the four commutators are so disposed that the metal contact
surfaces stand quartering, and each one shall occupy a distinct quadrant. On the

page_text: other hand each of the corresponding disks of on every commutator are similarly.
arranged in quadrature, but the two disks o o on the individual commutators
are so set with respect to each other, that the metallic surfaces n n shall be
diametrically opposite.
Thus in reversing the motor, it is only necessary to shift the brushes, which are
mounted in a properly pivoted carriage or sliding support M, from one commuta-
tor o to a second, but diametrically arranged cooperating commutator of, thus a
pull or thrust is exerted in an opposite direction upon the shaft and the latter is
started in a reverse path of rotation from that just before accomplished. To stop
the machine it is only necessary to move the brushes by means of the lever and
carriage M to a position midway between the two disks o 0, forming each
commutator, or in other words allow them to rest upon the insulating disks p.
Thus all the helices or electro-magnets are for the time being rendered inactive
and the machine remains stationary.
The actuating instrumentalities by which alternate thrusts, exerted upon the
cross-head effect and transmit their force to the shaft in order to rotate the same,
is accomplished by means of circular disks e³ e, which correspond to the crank in
an engine. These disks are centrally and loosely pivoted upon crank-pins g³ gª
eccentrically disposed upon cranks fƒ ƒ, the latter however being centered upon
those portions of the shaft, which go to constitute the main shaft E, all as herein
before premised.
Thus each of the crank disks e etc. rotates upon the interior periphery of the
cross-head enclosing it. As the cross-heads reciprocate transversely of the shaft by
the influence of the current passing through the helices, which latter attract the
armatures attached to the lever arms and connecting-rods secured to said cross-
heads, pressure is brought to bear against said disks, which move away from the
thrust so exerted, and by this means the revolution of the shaft is accomplished by
the movement of an epicycle, so called.
The operation of the motor is accomplished by shunting or shifting the current
successively through the circuit wires designated by the numerals 1, 2, 3, 4, by
means of the instrumentality of the commutator disks and their brushes, which
latter by passing from the insulating material to the metallic surfaces composing
said disks, effect certain ones of the helices to render them active, while others in
the series of helices are made inactive at proper intervals of time, and so maintain
a continuous succession of thrusts to rotate the shaft from which the motive power
is to be furnished.
The battery may consist of any number or series of cells, adapted to give a
current of electricity most suitable for a machine of the above description, and is
shown at N. The current generated therefrom has the same general direction with
reference to the helices, only it is forced by means of the commutators to shift is
course to render certain of the helices active, while the remainder are rendered
inactive.
The helices are arranged, as shown, in pairs in lieu of being single in order to
obtain more power, while the length of the armatures is accordingly extended to
suit existing circumstances. It is evident from the arrangement and system of
the helices, herein described, that a second connecting rod may be united to the
rods, as shown, and in axial alignment therewith, while a secondary series of
helices may be disposed in rear of the first series, making the entire series two
deep, and thus augmenting the power twofold upon each connecting rod.
By this means the power of the machine can very easily be greatly multiplied
without increasing the size very much and at a very small expense or cost.
It must be understood from my invention that the cross-heads B* B* B7 B8
cooperate alternately in pairs, that is B B7 act together and B* B*; and the
current is so disposed, that the opposite pairs of the helices are rendered active and
thus two opposite thrusts are exerted simultaneously upon the shaft to aid its.
revolution. Upon reference to Fig. 1 this idea is more easily explained and so it
will readily be seen that the alternate cross-heads with their operating mechanism,

page_text: act together simultaneously but in different directions, as shown by arrows 1.
and 2; thus the cross-heads B5 B7 are now active having just completed their
stroke and the helices or electro-magnets, which have been employed to effect these
thrusts by attraction upon the armatures D D are A¹ A' a¹ a¹ upon the cross-
head B, while the opposite helices CC c¹ c¹ of the similar acting pairs of electro-
magnets operate the cross-head B7 by the armature D7 D'.
The resultant or active thrust derived from the above position of parts effects
positive movement of the shaft for 90° degrees, or one quarter of an entire or
complete revolution.
This is accomplished by means of the metallic contact surface of its commu-
tator I' with the brush during that distance, which directs the current No. 1,
through the helices A¹ A¹ a¹ a¹ C C¹ c¹¹, as above premised.
The instant brush ¹ has broken its metallic contact with its commutator, the
metallic contact surface J' has completed the circuit by aid of its brush j³
through the wire, which conducts current No. 2, the latter induces activity in the
pairs of helices E* E* e³ e² H'H' h' h' and their respective cross-heads B6 B8 are
oppositely thrust, as shown by the arrows 3 and 4. This completes the second
quarter or 90° of a complete revolution of the shaft, when the brush and its
commutators have broken their metallic contact, and the armatures are free to
withdraw from their helices.
This position of parts is shown in Figs 1,,6, 7, 8 and 9; in the four latter figures
diagrammatically represented, it will be easily seen that commutator I has just
broken contact with its brush ¹, while J' has just completed contact with its
brush, hence the current is on wire No. 2; the helices then active are E* E³
H* He¹ e h³ h2, while the commutators I¹ K L are inactive with the current.
shunted off.
°
In Fig. 2 is shown a different position of parts and the crank disk e³ is then
upon its extreme throw to the left, just commencing its active thrust, as shown
more fully in Fig. 3. At this time commutator K is then in contact with its
brush and has vitalized the helices B³ B³ ³ ³ D³ D³ d³ d³ and attract their
armatures D D D7 D7 to thrust the crank-disk e simultaneously with e³, but in
the opposite direction.
Upon the breaking of this current commutator K³ and brush k³ have closed the
circuit upon the wire, conveying current No. 3, and the cross-heads B and B are
again brought into active operation by aid of the oppositely disposed pairs of
helices from that employed upon the first quarter of the revolution.
In this instance helices BS BS 63 b³, D³ Û³ ď³ ďare now active and opposite
thrusts are effected respectively to those shown by arrows 1 and 3, in the first
quarter of the stroke; metallic contact is maintained between commutator K³ and
its brush for 90° degrees of arc, and thus an active thrust is obtained in order to
complete the third quarter of the revolution of said shaft E.
When the current No. 3, over its wire is broken by the insulating material
of K³ meeting its brush, commutator L has effected metallic contact with its
brush and current No. 4, is induced through the proper wires to actively operate
the helices F. F' ƒ ƒ* G* G* g' g' and with the armatures and operating
mechanism connecting the cross-heads B6 and B³, each of which are oppositely
thrust from the direction taken by them on the second quarter of the revolution,
ns shown in Fig. 1, by arrows 3 and 4. This completes the fourth quarter and the
complete revolution of the main shaft has been actively and continuously effected
by the thrusts from the cross-heads resulting from the successive activity of the
various pairs of helices forming the entire series.
At this time or upon the completion of one entire revolution, commutator I' and
brush are again in contact and current No. 1, is actively employed to operate
the helices A¹ A¹ a¹ a¹ C¹ C¹ c¹ c¹ and their operating mechanism, as hereinbefore
fully described.
To a more complete understanding of the active operation and position of
parts.during portions of one complete revolution I have shown in Figs. 6, 7, 8,

page_text: and 9, diagrams of the position of the crank-disks simultaneously with respect to
their individual cross-heads, while below is represented the position of the
commutators and their respective brushes. These four figures illustrate one quarter
of an entire revolution of the shaft E.
In order to ensure freedom of motion to the crank-disks ee, when they cease
their active movement, or during the time they are passing from one active position
to another, it is necessary that the periphery of the cross-head should be removed
slightly therefrom. Now it is evident, that the crank-disks travel in arcs of circles
with the shaft E as the center, and upon reference to Fig. 6 one of said cranks is
therein shown as just commencing the inactive portion of the revolution with the
armatures commencing to reverse their motion and preparatory to advancing
towards B 63, but this motion would throw the cross-head B against the crank,
and prevent its advance forward motion, or in other words tend to drive it back to
its position at the commencement of its active stroke. It is in order to prevent
this antagonistic action of the cross-heads and their cranks, that I have made the
interior periphery of said cross-heads circular, but have given them a stroke
sufficient to throw them from the center to permit of the advance of the crank-
disks and yet allow the armature to advance in the opposite direction required,
without retarding said crank-disk.
Thus when the disk has ceased its activity the cross-head still advances
eccentrically of its enclosing crank and thus, while the armature is reversing its
motion, the crank has reached a second active position and simultaneously therewith
the cross-head by the action of its armatures has returned from its eccentric position
and is in readiness to again exert a positive active thrust upon the crank-disks to
induce positive forward motion of the main shaft.
This is more fully illustrated by reference to Fig. 4, of the drawings. At the point
marked u, the active thrust from the cross-head, moving in the direction of the
arrow, as designated, ceases and the latter advances the distance, shown between
the full and. dotted lines in said drawing; during this movement the crank has
advanced to the point marked v. But while said crank is passing from v to w the
cross-head has returned to its active position concentric with its crank in readiness
for an active thrust through an arc of 90° degrees.
In Fig. 5, is shown a slight modification in which a small disk q is employed,
suitably mounted upon a crank r, by this means I am enabled to increase the
length and consequently the power of the latter upon the shaft to produce rotary*
movement.
By a close examination into the system and arrangement of the parts composing
my invention, it is easily understood that various modifications may be introduced
therein without effecting the spirit and essence of my invention, and although
I have described and illustrated the machine, as being operated by four distinct
active thrusts in order to complete one revolution of the driving shaft, still it is
very evident that this may be easily modified by changing the number of com-
mutators and likewise altering the length of arc comprised in the metallic contact
surface. Thus each of the latter elements may contain only 45° degrees of arc,
hence this would necessitate eight commutators and eight corresponding cross-heads.
By this means the shaft would receive eight active thrusts in lien of four and the
resultant or power obtained would be very materially increased.
.
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
.
1st In an electro-magnetic machine the combination with a single brush or
contact device of the compound commutators insulated with respect to each other
and with the metallic portion of their peripheries diametrically opposed, whereby
the direction of the motor may be reversed by the shifting of the brush
substantially, as herein set forth.

page_text: 2nd In an electro-magnetic engine the combination of a series of helices and their
cooperating mechanism with a driving shaft provided with a pair of cross-heads
actuated by said helices and provided with openings 65, which enclose said cranks,
the arrangement of cranks and cross-heads allowing the latter to exert opposite
alternate thrusts upon said shaft, for effecting the rotation thereof substantially as
set forth.
3rd In an electric motor the combination with a main shaft having a crank, of a
cross-head provided with a recess to enclose said crank, and device for reciprocating
said cross-head to rotate said shaft by its action on said enclosed crank, the opening
a recess in said cross-head being of sufficient size, and said cross-head being given
sufficient thrust to prevent contact between said cross-heads and said crank, while
the latter is passing from an inactive position to an active position, substantially
as set forth.
4th In an electric-motor, the combination of a cross-head having a circular
opening 65, with a main shaft provided with a crank having a disk arranged within
said openings, the impulse of said cross-head being communicated to said disk by
contract of the wall or side of the opening therewith, and thereby causing the
rotation of said main shaft, substantially as set forth.
5th In an electric-motor the combination with a shaft, a pair of cranks on said
shaft, and a pair of cross-heads each provided with an opening 65, which respectively
enclose said cranks, of two commutators, their brushes, and the electric generating
and conducting devices, which cause said cross-heads to act alternately on said
cranks and shaft, substantially as set forth.
6th The combination with a shaft adapted to furnish motive power, its cranks
enclosed by and rotating within reciprocating cross-heads, and the cooperating
armatures and helices, of a series of commutators and brushes, and the necessary
electric connections, whereby said commutators are connected to said helices and
effect successive active thrusts upon said shaft to compel rotation thereof,
substantially as herein described.
7th In an electro-magnetic machine the combination with a single brush, of a
compound commutators, provided with two diametrically opposed metallic contact
surfaces and a disk composed entirely of insulating substance, whereby upon
shifting of the brush thereon, the machine is stopped substantially as stated.
8th In an electro-magnetic machine the main shaft, reciprocating armature and
cross-head, of a crank disposed thereon, said crank being provided with a disk,
which is disconnected from and actuated intermittently by the said cross-head to
which is secured the said reciprocating armature, substantially for purposes
herein set forth.
9th In an electro-magnetic engine the combination of a main shaft and a crank
formed thereon with a reciprocating armature, an electro-magnet and a cross-head,
which is actuated by said magnet and armature, said cross-head being unconnected
to said main shaft, but intermittently engaging therewith to rotate said shaft,
substantially as set forth.