IMPROVEMENTS IN ELECTRICAL MACHINES
Year: 1874

page_text: LETTERS PATENT to George Tomlinson Bousfield, of Sutton, in the
County of Surrey, for the Invention of "IMPROVEMENTS IN ELECTRICAL
MACHINES."A communication from abroad by Henry Julius Smith,
of Boston, in the State of Massachusetts, in the United States of
America.
COMPLETE SPECIFICATION filed by the said George Tomlinson
Bousfield at the Office of the Commissioners of Patents, with his
Petition and Declaration, on the 29th January 1874, pursuant to
the 9th Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
TOMLINSON BOUSFIELD, of Sutton, in the County of Surrey, send.
greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN ELECTRICAL MACHINES," and have petitioned Her most Excellent Majesty

page_text: nor does it condense moisture in the form of a num, but rather in the
form of detached drops.
The machine proper consists of an outer covering or shallow box A
made of vulcanite, containing a frame plate C, a Leyden jar or con-
denser D, a generating plate B, and devices for operating the generating
plate and condenser in connection. The machine proper however is
incased within a wooden lox Z, and can be operated within that box as
herein-after set forth.
The frame plate, the condenser, and the generating plate are placed
parallel to each other, and parallel to the top and bottom of the shallow
vulcanite box, as shewn.
The condenser D is connected to the frame plate C by four posts 1, 2,
3, and 4.
The generating plate B lies between the condenser and frame plate,
and is revolved on its axis E by means of the handle or crank F. This
axis E passes tightly through a stuffing box G which is screwed into the
vulcanite covering A, and which may be made to grasp the axis more or
less tightly by means of the packing screw H. The inner end of the
axis has its bearing in a step in the outer vulcanized plate of the con-
denser.
་
The generating plate B revolves between two cushions I and K, the
surfaces of which are coated with an amalgam as is usual with electrical
machines. For this amalgam bi-sulphide of tin with wax is preferred.
It is best that the backing of the cushions should be made of non-
conducting material (hard rubber), and when thus made springs to keep
the cushions in contact with the generating plate with sufficient force
may be provided by cutting the hard rubber as shewn in Figures 3
and 8.
The cushions are provided with flaps, one of which is shewn at M,
Figures 3 and 5; these serve to prevent the electricity from escaping
from the generating plate B until the excited portion of its surface
arrives in the neighborhood of the collectors P which are serrated
strips of metal placed one on each side of the plate B, as seen in
Figures 2, 3, 5, and 6, and both collectors are attached to and in
"

page_text: metallic connection with the frame post 4, and by the post are brought
into contact with the two plates r, r, or outer surface of the Leyden jar
or condenser. The two plates 8, 8, forming the inner surface of the
condenser are in metallic connection with the post 2, and also with the
cushions I and K by means of post 1. The two plates r, r, the outer
surface of the jar, connect with post 3 as well as with post 4. The
frame plate and the generating plate are made of vulcanite.
The condenser or Leyden jar D is constructed in the following
manner: Vulcanite is taken in a plastic state, and upon a layer of
vulcanite is placed a layer of tin foil. Over the layer of tin foil there is
placed a second layer of plastic vulcanite, and then a second layer of
tin foil. A third layer of plastic vulcanite, a third of tin foil, a fourth
of vulcanite, a fourth of tin foil, and a fifth of vulcanite completes the
jar or condenser.
The first and third layers 8, 8, of tin foil form the inner surface of the
jar or condenser, the second and fourth layers r, r, forming the outer
surface. Care must be taken that the diameter of the tin foil plates be
less than that of the layers of plastic rubber, excepting a small pro-
jection from each tin foil plate intended to connect with the posts of the
frame, as shewn in Figure 7, see also Figures 4 and 6. The condenser
thus made up is then submitted to the baking or vulcanizing process, at
the end of which it becomes hard and rigid. The surfaces r, r, and 8, 8,
will for ever remain in a perfectly dry condition.
The posts 1, 2, 3, 4, are now screwed into the condenser D, posts 1
and 2, as before stated, connecting with the outer surface .r, r, while
posts 3 and 4 connect with the inner surface 8, 8.
To the outer vulcanite covering A are attached two electrodes W
and V for the discharge of the electricity when they are brought into
contact with the outer and inner surfaces r, r, and 8, 8, of the jar which
is done by turning the handle of the machine backward a little until the
post 3 comes into contact with a projection from the electrodo V, and
the post 2 comes into contact with a projection from the electrode W.
There is a stop ✗ which serves to prevent the framework of the
machine from revolving by the action of the crank, except through a
small arc. The framework with the posts supported by it is limited in
.

page_text: its forward motion by the stop X, and in its backward motion by the
projection from the electrode V.
The vulcanite casing A is a box with a cover, as shown in Figures 2,
3, and 4. This casing or covered box is further protected by a rubber
pouch O which fits tightly over the joint between the cover and box,
while the part in contact with the bottom of the box is loose, as shewn
in Figures 2 and 4, to be used as a diaphragm for a purpose next to be
described. In the bottom of this box A are four holes (two are shewn
in section in Figure 2). The diaphragm lies between these holes and
the outer wooden case or box Z, and serves to keep the same atmosphero
within the machine proper.
R, R¹, are annular plates used for packing the machine proper within
the casing Z, they also keep the pouch O in place.
The operation of the machine is as follows:-By turning the crank F
the generating plate is revolved between the cushions I and K. The
electricity generated is collected by the collectors P, P, and from them
carried by post 4 to the inner surface of the jar. The opposite clectricity
appearing at the rubbers I, K, is conducted from them by post 1 to the
outer surface of the jar.
By continued turning of the crank the Leyden jar or condenser may
be charged sufficiently to give a spark of from three to four inches in a
machine ten inches in diameter.
The first motion of the crank turns the frame as well as the generating
plate until post 3 strikes the stop X. Turning the crank backward
brings posts 3 and 2 into contact with the electrodes V and W respec-
tively when the condenser may be discharged. It is desirable that the
condenser be discharged by the posts 3 and 2 rather than by posts 1
and 4 which are used for charging, as the tendency to escape during
accumulation is thereby avoided.
The capacity of a Leyden jar or condenser constructed of plastic
rubber and metallic plates as above directed may be increased by adding
successive layers of metal and vulcanite; it may be decreased by using
fewer layers. Such condensers will be of use for electrical purposes
independently of the generating apparatus herein described.

page_text: Instead of the annular plates R, R, for packing the machine proper
in the wooden case and keeping the pouch O in place, sometimes
when building large machines the machine is confined with its pouch
between strong iron ring plates by means of bolts and screws, as shewn
in Figures 9 and 10; these ring plates are then screwed into the outer
wooden box, and by their strength and firmness prevent the apparatus
within the vulcanite casing from becoming displaced.

page_text: 10. The machine proper, herein described, when confined within
annular metallic plates by bolts and screws, as shewn in Figures 9
and 10.
In witness whereof, I, the said George Tomlinson Bousfield, have
hereunto set my hand and seal, this Twenty-ninth day of January,
in the year of our Lord One thousand eight hundred and seventy-
four.