IMPROVEMENTS IN ELECTRO-MAGNETIC ENGINES
Year: 1875

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn
Fields, in the County of Middlesex, Gentleman, for the Invention
of "IMPROVEMENTS IN ELECTRO-MAGNETIC ENGINES."-A communication
from abroad by José Santiago Camacho, of Paris, in the Republic of
France.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 1st October 1875.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN ELECTRO-MAGNETIC ENGINES," a com-
munication to me from abroad by José Santiago Camacho, of Paris, in
the Republic of France, to be as follows:-

page_text: armature and upon an arrangement of commutator, enabling the speed
and power of the engine to be varied.
The engine may be constructed in two different modifications, according
as the electro-magnets are made fixed or stationary and the armatures
moveable, and vice versa.
In carrying out this Invention as applied to a rotary electro-magnetic
engine in which the electro-magnets are fixed or stationary and the
armatures moveable, the apparatus is constructed and arranged in
the following manner :-The armatures of the electro-magnets are
composed of a suitable number of metallic plates or blades arranged
normally at the acting surface of the electro-magnets, and magnetically
insulated from one another by the interposition of any suitable sub-
stance, such, for example, as paper, resin, or certain metals which form
bad conductors of magnetism. In this manner the magnetization is
produced successively in each of the plates of which the armature is
composed, and which in consequence of their small volume are thus
brought to a condition of maximum magnetization as soon as they come
within the range of magnetism of the electro-magnets of the engine, and
the travel of the armature is completed in the condition of maximum
magnetization, whence results a greater production of force with the
same expenditure of electricity.
In the system of commutator employed according to this Invention,
the piece of metal or contact maker serving as a conductor, in lieu of
boing made of a rectangular shape, is constructed of the form of a
trapezium or triangle, so that the rubber which acts against it continues
in contact therewith during only a fraction of a revolution, varying
according to the position in which the contact maker is placed. It will
thus be seen that it suffices (when the rubbing surfaces of the engine
remain stationary) to advance or draw back the commutator upon its
axis of rotation in order to modify the passage of the currents in the
electro-magnets, and consequently to regulate the speed and power of
the engino.
As an example of a convenient arrangement of the apparatus it is
proposed to employ, say, four electro-magnets fixed at equal distances
apart from one another between two discs serving as a frame and support
to the whole of the apparatus. The moveable part of the engine is com-
posed of a shaft or axis, upon which are fastened recessed or hollowed

page_text: discs, to the periphery of which the armatures are attached. These
armatures in the present example are three in number, and they are
formed, as before mentioned, of a series of plates or blades of metal
insulated electrically from one another, and arranged in parallel or
radiating positions.
The shaft before mentioned also carries the commutator, which is of a.
cylindrical form in cross section, and in contact with which roll four
rollers, each of which is in communication with one of the electro-
magnets.
The current enters the apparatus by a binding screw, passes into the
frame, thence into the shaft and into the commutator, whence it reaches
the rollers, which direct it successively to each of the electro-magnets by
the intervention of binding screws insulated from the frame and fixed
on a disc of wood or other insulating material.
The current issues from the electro-magnets to other binding screws
situate at the opposite end of the frame and attached to a metallic ring
uniting them all, and which ring is insulated from the frame by a disc
of wood or other suitable material; the current then passes off by
another binding screw situate at the same end of the frame to return to
the battery.
On the circuit of the wires for inducting and educting the current
there may be placed an ordinary commutator, which enables the engine
to be set in motion or stopped as required.
The improved commutator mounted on the shaft of the engine is pro-
vided with triangular contact makers, as before mentioned, admitting of
the duration of the passage of the current being varied or regulated in
each electro-magnet, according to the position given to these contact
makers relatively to the friction rollers. The adjustment is effected by
causing the commutator to slide along parallel with itself upon the
shaft into the required position, in which it is maintained by a suitable
screw.
The blades of the armatures, which are magnetically insulated from
one another, as before mentioned, may be made of a triangular or tra-
pezoidal form in section; or the armatures may be composed of any
suitable number of parallel blades arranged in juxtaposition, but mag-
netically insulated from one another by any suitable means.

page_text: It is further proposed to construct the clectro-magnets of tubes of
rectangular, square, cylindrical, or other convenient section, arranged
the one inside the other; or ordinary electro-magnets may be used with
solid cores, and arranged in any required number round the apparatus.
As a modification of the arrangement herein-before described, the
armatures may be fixed at the exterior of the apparatus, whilst the
electro-magnets are arranged upon the internal revolving drum of the
engine.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent 1
Office on the 28th March 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of October, in the year of
our Lord One thousand eight hundred and seventy-five, in the 39th
year of Her reigu, did, for Herself, Her heirs and successors, give and
grant unto me, the said John Henry Johnson, Her special license that
I, the said John Henry Johnson, my executors, administrators, and
assigns, or such others as I, the said John Henry Johnson, my 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 Isle of Man, an Invention for "IMPROVEMENTS IN
ELECTRO-MAGNETIC ENGINES," a communication to me from abroad by
José Santiago Camacho, of Paris, in the Republic of France, upon the
condition (amongst others) that I, the said John Henry Johnson, my
executors or administrators, by an instrument in writing under my
hand and seal, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in
and by the following statement, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to
say :-
The said Invention relates to a novel system of electro-magnetic
motive-power engines, based chiefly upon the employment of an
improved armature and upon an arrangement of commutator, enabling
the speed and power of the engine to be varied.
The engine may be constructed according to two modifications, the
electro-magnets being either stationary and the armatures moveable, or
vice versa. In both cases the principle and operation of the apparatus
remain the same, the details only of the engine being varied.
The armatures are formed of metallic plates insulated magnetically
from one another in order to cause the engine to generate a greater
amount of force. The magnetic inertia of a temporary magnet is so
much greater in proportion as the volume or mass is increased, con-
sequently a comparatively long time is required in order for it to attain
its maximum of magnetization if the mass is considerable. Moreover,
in the case in question, and when the armature is placed in proximity to
the magnet it has a tendency to become magnetized throughout its
whole extent, which result is very unfavourable.
It should further be observed that the nearest part of the magnet
(which is alone effective) cannot attain its maximum amount of
magnetization except at the same time as the whole of the armature,
that is to say, when the latter has arrived opposite the magnet. Now it
is precisely at this instant that in rotatory electro-magnetic engines the
passage of the current which produces the attraction would cease,
whence it results that the armature has finished its course or travel
without attaining its maximum of magnetization, and consequently a
great diminution of the force which would otherwise be produced by the
engine ensues.
In order to remedy these defects the armatures of the electro-magnets
are according to this Invention composed of a suitable number of
metallic plates or blades arranged normally at the acting surface of the
electro-magnets and magnetically insulated from one another by the

page_text: In the apparatus shewn in the Drawing the electro-magnets A. (shewn
detached in Figure 3) are four in number and fixed at equal distances
apart from one another between two discs B, serving as a frame and
support to the whole of the apparatus. The moveable part of the
engine is composed of a shaft or axis C, upon which are fastened
recessed or hollowed discs D, to which the armatures E are attached.
These armatures in the present example are three in number, and they
are formed as before mentioned of a series of plates or blades of metal
insulated electrically from one another and arranged in parallel or
radiating positions, as shewn in the Drawing.

page_text: by causing the commutator to slide along parallel with itself upon the
shaft C, on which it is carried into the required position in which it is
maintained by the screw S.
The blades of the armatures which are magnetically insulated from
one another, as shewn in the Drawing, may be made of a triangular or 5
trapezoidal form in section, but as previously stated for the sake of
greater simplicity, the armatures may consist of any suitable number of
metal blades with parallel faces arranged in juxtaposition, but magnet-
ically insulated from one another by any suitable means.
The electro-magnets employed in the engine are by preference 1
constructed of tubes of a cylindrical, rectangular, squarc, or other
convenient section, an example of which is shown in Figure 3", but
ordinary electro-magnets with solid cores may be employed arranged in
any required number round the apparatus.
Figure 7 illustrates a modification of the arrangement herein-before 1
described, in which the armatures are fixed at the exterior of the
apparatus, whilst the electro-magnets are arranged upon the internal
revolving drum of the engine; all the other arrangements of the apparatus
however are similar to those herein-before described.
The engine may be constructed of any dimensions; in the Drawing 2
bars or bolts are shown at T for the purpose of securing it either to a
fixed framework or to the object itself, to which it is to impart
motion.
The engine is applicable to industrial purposes generally, such for
example, as for driving sewing machines, working musical instruments, 2
machine tools, and the like. It may likewise be employed by constructing
it of suitable dimensions for the hauling of vehicles upon rails or upon
the ground, as well as propelling vessels, or for imparting motion to
other description of apparatus.
Having now described and particularly ascertained the nature of the 3
said Invention and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider
to be novel and original, and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is,―
First. The application and use of tubular electro-magnets, substan- 8
tially as and for the purpose herein-before described,

page_text: Secondly. The system of armatures herein set forth formed of blades
insulated magnetically from one another, and arranged normally at the
acting surface of the magnet, substantially as and for the purpose herein-
before described.
Thirdly. The system of commutators with triangular or trapezoidal
contact makers arranged so as to admit of the duration of the passage of
the current in the electro-magnets being regulated with facility, and of
the consequent variation in the speed and power of the engine, substan-
stantially as herein-before described.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, this Twenty-eighth day
of March, One thousand eight hundred and seventy-six.
1
ATTIAN