IMPROVEMENTS IN ELECTRO-MAGNETIC MACHINES
Year: 1862

page_text: LETTERS PATENT to Jacob Baynes Thompson, of Moreton Place, St.
George's Square, Pimlico, in the County of Middlesex, for the Invention
of "IMPROVEMENTS IN ELECTRO-MAGNETIC MACHINES."
PROVISIONAL SPECIFICATION left by the said Jacob Baynes Thompson
at the Office of the Commissioners of Patents, with his Petition, on the
2nd September 1862.
I, JACOB BAYNES THOMPSON, of Moreton Place, St. George's Square,
Pimlico, in the County of Middlesex, do hereby declare the nature of the
Invention for: "IMPROVEMENTS IN ELECTRO-MAGNETIC MACHINES," to be as
follows
1
My. Invention consists in a mode of applying the enormous attractive force
of the electro-magnet to the moving of machinery. The electro-magnet may
be employed directly to produce a rectilinear oscillating motion, but as the
force of the electro-magnet is effective only at a very short distance, these
oscillations are too short to apply. the great power in any beneficial way for
moving machinery; hence almost all attempts hitherto made at applying
electro-magnetic force have been in rotatory engines; but these machines, even
when of the largest size, have produced but small effects.. The difficulty to be
overcome is to apply the direct pull of the magnet, and at the same time to
obtain sufficient length of stroke. This. I have done by combining a number
of electro-magnets into a series, the electro-magnets being placed one beyond
the other, and having their opposite poles at very short distances from each
other, so that when the current passes, these electro-magnets attract- simul-
taneously. By this means I get the full force of the electro-magnet, and by

page_text: adding to the number in the series of magnets, I get any desired length of
stroke. This series of magnets is in imitation of a muscle in the animal body,
the short magnets representing the striae of the muscle, and they contract in a
similar manner, being really an iron muscle. It is preferred for the magnets
to be coiled in the following manner:-Instead of each magnet carrying its
own coil in the ordinary way, each preceding magnet carries also the coil
of the succeeding magnet, and the succeeding magnet is able to move freely
through its coils which are on the preceding magnet, so as to approach to or
recede from the opposite poles of the preceding magnet; thus, there is not
only the mutual attraction of the opposite poles of the two magnets lying next
each other in the series tending to draw the two together, but also the attrac-
tive power of the hollow coil which is on each preceding magnet, a hollow coil
having the power of drawing a mass of iron into its centre. The magnets may,
however, be coiled also in the ordinary manner, each carrying its own coil.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Jacob Baynes Thompson in the Great Seal Patent Office on
..the 2nd March 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JACOB
BAYNES THOMPSON, of Moreton Place, St. George's Square, Pimlico, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her.Letters
Patent, bearing date the Second day of September, in the year of our Lord.
One thousand eight hundred and sixty-two, in the twenty-sixth year of Her
reign, did, for. Herself, Her heirs and successors, give and grant unto me,
the said Jacob Baynes Thompson, Her special licence that I, the said Jacob
Baynes Thompson, my executors, administrators, and, assigns, or such.others as
I, the said Jacob Baynes Thompson; my executors, administrators, and 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 Inven-
tion for "IMPROVEMENTS IN. ELECTRO-MAGNETIC MACHINES," upon the condition
(amongst others) that I, the said Jacob Baynes Thompson, my executors
or administrators, by an instrument in writing under my, or their, or one
of their hands. and seals, 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
-

page_text: within six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Jacob Baynes Thompson, 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 thereof, that is to say:
My Invention consists in a mode of applying the enormous attractive force
of the electro-magnet to the moving of machinery. The electro-magnet may
be employed directly to produce a rectilinear oscillating motion, but as the
force of the electro-magnet is effective only at a very short distance, these
oscillations are too short to apply the great power in any beneficial way for
moving machinery; hence almost all attempts hitherto made at applying
electro-magnetic force have been in rotatory engines; but these machines, even
when of the largest size, have produced but small effects. The difficulty to be
overcome is to apply the direct pull of the magnet, and at the same time to
obtain sufficient length of stroke. This I have done by combining a number
of electro-magnets into a series, the electro-magnets being placed one beyond
the other, and having their opposite poles at very short distances from each
other, so that when the current passes, these electro-magnets attract simul-
taneously. By this means I get the full force of the electro-magnet, and by
adding to the number in the series of magnets I get any desired length of
stroke. This series of magnets is in imitation of a muscle in the animal body,
the short magnets representing the striæ of the muscle, and they contract in a
similar manner, being really an iron muscle.
Figure 1 is a side view of a machine constructed according to my Invention.
a, a, are two end frames connected together by bars b, b, which serve as guides
for the plates c to slide upon. One of these plates is shown separately at
Figure 2, this Figure being a front view thereof; it consists of a central plane
c¹, on which on each side are formed or fixed the projecting pieces c2;. these
are planed true on their faces, and are each wound round with insulated, wire
or strips of copper or other metal, as is partly shown in the Drawing, and the
insulated wire or strip after encircling one projection a sufficient number of
times, passes to the next, and so on. In this manner all the projections on
both sides of the central plane are similarly clothed with the insulated wire or
strip, the winding being so arranged that when the ends of the insulated
wire or strip are connected with a battery, or batteries, or other source of
electricity, the positive and negative poles will alternate às is marked on
the Drawing; and where there is a positive pole on one side of the central
plane, the corresponding pole on the other side of the central plane is negative,

page_text: and so on throughout. 3, c³, are brass guides attached to the plate and fitted
accurately to the bars b, b, so as to be able to slide freely thereon. The plates
are connected together throughout the series by the links c, c, of which there
are four.on each side between each plate and the next; these are secured to
the plates by screws c, but the holes in the links are slotted a short distance,
so that they allow the plates to come in contact or nearly so, and also to
separate a short distance, say, one-eighth of an inch. The insulated wires or
strips with which the projections of the plates are wound, are so connected
with the battery, or batteries, or other source of electricity, that when the
current passes the magnetism of the poles of two adjacent plates, which are
situated opposite to each other, shall be of opposite signs, so that they may
attract each other.
As will be seen in the Drawing, two sets of plates are employed, and this is
a convenient arrangement, but it may be varied. One of the end plates of
each set is connected to one end frame of the machine, and the other end plate
of each set is by a short connecting link coupled with the lever e, which is
capable of rocking on an axis at f. At the further end of the lever e a con-
necting rod g is jointed, and this communicates the motion of the lever e to
the fly wheel h. The connection between the coils. of the several plates or
compound electro-magnets and the battery or source of electricity, is made by
means of a slide connected with the lever e, or otherwise conveniently arranged,
so that when the plates are at their furthest distance apart, or just before this
time, the connection is made and the magnets rendered active; and when by
their mutual attraction the plates are drawn nearly into contact, or just before
this time, the connection is broken, and thus the continuous action of the
machine is maintained. I prefer to wind the magnets with a copper strip,
such as is shown at Figures 3; this strip is insulated by winding silk ribbon
around it. The plate c may be rolled with the projections to form the poles
upon them, or the poles may be otherwise formed in, one piece with the plate,
and it is preferable so to make them; but the poles may be fixed on to the
plate by rivets or screws, and in this case the fibre of the metal should run in
the same plane as that in which it is wound, or the whole plate and poles may
be cast in malleable iron or annealed cast iron; wrought iron is, however, a
preferable material. It is preferred to make vertical cuts in the poles, as is
shown at cx, cx, so as to divide them either completely or partially into
separate pieces down to the level of the central plane; this increases the
of the machine, making the magnet equal to a built-up magnet.
Figures 4 show the manner in which the flat strips or metal ribbons are bent
in passing from the exterior of one coil to the interior of the next.
power

page_text: Although the method of coiling above described is that which is most
readily adopted, still, to obtain the maximum effect, it is preferred for the mag-
nets to be coiled in the following manner :-Instead of each magnet carrying
its own coil in the ordinary way, each preceding magnet carries also the coil of
the succeeding magnet, and the succeeding magnet is able to move freely
through its coils which are on the preceding magnet so as to approach to or
recede from the opposite poles of the preceding magnet; thus, there is not only
the mutual attraction of the opposite poles of the two magnets lying next each
other in the series tending to draw the two together, but also the attractive
power of the hollow coil which is on each preceding magnet; a hollow coil
having the power of drawing a mass of iron into its centre.
Figure 5 is a plan of a plate similar to that shown at Figure 2, but con-
structed so as to be wound in the different manner above set forth.
These
On the central plane a number of rings cs, es, are fixed or formed.
have spaces left in them at c*, c*; the insulated wire or strip is led in through
the spaces c*, and is wound around the central ring; the coil is made twice
the depth of the ring, and is lined by preference with a thin split tube of brass,
in the same manner each of the succeeding rings is surrounded with a coil of
twice its depth, and the coils are connected together in such a manner that
if the current be passed so as to make the central ring positive, the ring next
it is negative, the next positive, and so on, as the Drawing is marked; the
other side of the plate has similar rings, but no coils, and these rings enter
within the projecting coils of the next plate. In the centre of each of the
innermost rings is a hole bushed to the full depth of the plate, and projecting
coils and rings, and accurately fitted to a guide bar b, of which in this case
only two are employed for each set or series of magnets. In other respects
the machine is substantially as already described. This arrangement leaves
no vacant space between the poles of the opposite magnets around which
the electric current is not passing, and consequently where its full force is not
being exerted; the arrangement is in this respect superior to that first
described.
In witness whereof, I, the said Jacob Baynes Thompson, have hereunto
set my hand and seal, this Twenty-seventh day of February, in the
year of our Lord One thousand eight hundred and sixty-three.
J. B. THOMPSON. (L.S.)