IMPROVEMENTS IN MAGNETS
Year: 1873

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 MAGNETS."-A. communication from abroad by
Hippolyte Fontaine, of Paris, in the Republic of France.
Sealed the 3rd June 1873, and dated the 31st March 1873.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 31st March 1878.
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 MAGNETS," a communication to me from
abroad by Hippolyte Fontaine, of Paris, in the Republic of France, to
be as follows :—
This Invention consists essentially in constructing magnets from a
number of thin flexible blades united together in the form of a bundle
in lieu of using rigid bars as heretofore, also in making such improved
magnets of steel wires united in the form of a bundle and held together

page_text: by polar pieces of soft iron or by non-magnetic metal ties or bands,
whereby a considerable increase of magnetism may be concentrated in a
comparatively small quantity of steel.
According to one mode of carrying out this Invention for the con-
struction of an improved magnet suitable for application to the well-
known magneto-electric machine of Gramme, two armatures of soft
iron which surround the ring of the Gramme machine are combined
with two > shaped bundles of thin blades, the extremities of which are
connected with the two armatures on opposite sides thereof, so as to con-
stitute two double poles.
According to another arrangement a bundle of thin steel blades of
an form is maintained laterally between two rigid straight magnets tied
together by copper bands or ties. A pressing screw acting upon the top
of the
shaped bundle serving to hold the thin blades together. Or
the shaped bundle of thin steel blades may bear laterally against two
magnetised wrought-iron bars held in position by wooden or metal
supports or cheeks, the thin blades being further held together at the
bend of the n by a metallic bridle piece.
According to another modification the improved magnet may be com-
posed of a bundle of thin steel blades bent or curved to a nearly circular
form thus A copper band or tie passes across the top of the nearly
circular bundle of thin blades and is secured at its lower ends to a
transverse piece of copper fitted into a wrought-iron socket piece, which
latter maintains the two extremities of the magnet in position.
According to another modification the thin steel blades forming the
bundle may be rigid as in the first modification, and bent to a ▲ form,
the extremities being maintained between two magnetised iron bars
fitted to a frame or support.
The armature in the four last described modifications is applied to the
ends of the lateral supporting bars, or to the wrought-iron socket piece
referred to in one of such modifications.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 26th September 1873.
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 Thirty-first day of March in the year
of our Lord One thousand eight hundred and seventy-three, in the
36th year of Her reign, 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, adminis-
trators, 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 MAGNETS," a communication to me from abroad by
Hippolyte Fontaine, of Paris, in the Republic of France, upon the con-
dition (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 per-
formed, 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.
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 accom-
panying Drawings, and to the letters and figures marked thereon, that is
to say :-
The said Invention consists in the production of a magnet which in
lieu of being made with rigid bars is formed of a series of very thin
flexible blades united into a bundle which admits of a much greater

page_text: amount of magnetism being concentrated in a small quantity of steel.
These blades are connected together either with pieces of copper or
with pieces of soft wrought iron or malleable cast iron, the function of
which is to receive and distribute the magnetism.
If desired in lieu of blades steel wires may be employed united into t
a bundle and maintained by polar pieces composed of soft wrought iron,
or by bands of non-magnetic metal.
And in order that the said Invention may be more fully understood
I shall now proceed more particularly to describe the same, and for that
purpose shall refer to the several Figures on the annexed Sheet of 1
Drawings, which represent examples of some of the arrangements it is
proposed to adopt.
In Figure 1, which shews an arrangement applicable to Gramme's
Machine A and B are armatures of soft wrought iron surrounding
Gramme's ring. a, b, shew a bundle of steel blades forming at A and B 1
two double poles.
Figure 2 shews an arrangement in which the bundle of steel blades a, b
is maintained laterally by two magnets C, D, connected together by
copper bands E, F. The bundle of blades a, b, is made fast and tight at
the top by means of a pressure screw G.
,
In Figure 3 the bundle a, b, is supported laterally on the bars H, I,
of magnetized iron, which are maintained by the outside bonds or
bands K, K, of wood or metal, and is fastened or tightened in the
middle by the strap or stirrup L.
Figure 4 shews the bundle formed of steel blades assuming a cir-
cular form. M is a copper band which is fixed at its lower part on to a
piece N, which piece is also composed of copper and is inserted into an
iron socket P.
In Figure 5 the steel blades a, b, are rigid as in Figure 1, and main-
tained between two bars R of magnetized iron inserted into a wooden a
frame S.
In Figures 2, 3, 4, and 5, U represents the armature of the magnet.
These arrangements may obviously be modified in many ways.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used

page_text: 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 construction and use of magnets in which the rigid bars
are replaced by a series of very thin flexible blades or wires united into
a bundle and connected together by pieces of copper, soft wrought iron,
or malleable cast iron.
Secondly. The herein-before described special arrangements of magnets,
as illustrated on the Drawing.
Thirdly. The application of these foliated magnets, whatever may be
their arrangement, to all branches of arts and manufactures in which
electro-magnets are employed, and especially to the electro-magnetic
machines on the systems of Gramme, Wylde, Siemens, Holmes, and
others.
In witness whereof, I, the said John Henry Johnson, have to
this my Specification set my hand and seal, this Twentieth day
of September One thousand eight hundred and seventy-three.
T
TATTINAT