Improvements in or relating to Electric Keyboards for Type-writing and Type-setting Machines and the like, also applicable for Circuit Closing Devices.
Year: 1894

page_text: Date of Application, 27th Mar., 1894-Accepted, 5th May, 1894
COMPLETE SPECIFICATION.
Improvements in or relating to Electric Keyboards for Type-writing
and Type-setting Machines and the like, also applicable for
Circuit Closing Devices.
A communication by CHARLES ELMER ALLEN, of 637, F Street, Washington, D.C.,
United States of America, Electrician.
I WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street
Manchester both in the County of Lancaster, and 323 High Holborn, in the County
of Middlesex, Civil Engineer do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
My invention relates to key boards for type writing, type setting and character
selecting machines, and has for one of its objects the provision of an improved
electric key board for use with type writing, type setting and other machines of
that character, and consists of a row or bank, or rows or banks, or assemblage of
thoroughly reliable electric contact keys of such construction as to be operated by
a very slight touch, and having a repetition of the alphabet, or pre-arranged series
of characters, words or phrases as many times as it may be desired, and occupying
such position and relation to each other that as many keys can be simultaneously
depressed as there are rows or banks upon the key board, for setting up a line of
type or other characters for printing. The invention also relates to improvements
in circuit closing devices, and has for its further object the provision of a simple,
compact and reliable circuit closing device, and this portion of the invention
consists essentially of a key or push button and a mercury contact therefor,
whereby a continuous and uninterrupted metallic circuit can be obtained, and it
also consists of such construction as to be operated by a very slight touch of the
hand, yet always insures a perfect metallic path for the circuit, uninterrupted by
dust, dirt or other defects common to electric keys, such as loose joints and sliding
contacts.
The invention consists essentially in a key board in which mercury or other fluid
electric conductor is used for establishing a circuit, and it consists of a case or
receptacle for the mercury or other liquid conductor and rows or banks of suitable
keys supported above the conductor in the case or receptacle in such a way and in
such position that the keys are projected into the mercury or other fluid conductor
by a very slight push or touch, and the invention further consists in the novel
construction and arrangement of the several parts hereinafter described, illustrated
in the drawings and more particularly pointed out in the claims hereunto appended.
In the drawings,
Figure 1 is a plan view of the key board and magnets showing the arrangement
of the circuits.
Figure 2 is a bottom plan view of the key support with the keys in position
therein.
Figure 3 is a transverse section of Figure 1 taken centrally thereof showing the
arrangement of the keys, conductors, key-support etc.
Figure 4 is a sectional view partly broken, showing the passage between the
compartments of the pan and the cock therein.
Figure 5 is a broken longitudinal section of the key board with some of the keys
removed, showing the chambers in which the keys are secured.
DO27

page_text: Figure 6 is a bottom plan view of a filler or mat for the mercury pan, and
Figure 7 is a vertical section of my improved circuit closing device showing the
relative positions and arrangement of the different parts.
of
Referring to the drawings by letters, A represents the base pan which is made
any suitable conducting material, preferably cast iron, and is divided by a
partition A into two compartments A¹ and A' for a purpose hereinafter described.
Communication between these two compartments is had through a channel or
passage a which is controlled by a cock a', as shown. The compartment A³ is a
storage or receiving chamber for the mercury and is provided with a cover F of
any suitable material, and has vent holes e at or near the forward end thereof.
E is a suitable thumb screw and is provided on its under surface with an elastic
washer, and screws into the top F so as to cover and close the vent holes e, as is
evident.
B is a block or plate of hard rubber or other insulating material, and is
preferably, rectangular in shape. B' are chambers cut or moulded in the plate B,
and B are openings extending from the chambers B' through the block B. These
openings B are of smaller diameter than the chambers B' whereby a shoulder or
ledge is formed in the top of the chamber B' and serves a purpose hereinafter set
forth. Into the chamber B¹ and through the opening B' is fitted a suitable key or
push button C. This key is shown in detail in Figure 7 and is more particularly
described in connection with said figure. Extending transversely of this plate B
are grooves or channels b between the chambers B¹ and for the purpose of receiving
and holding the wires or conductors c from the keys to the outside of the plate, as
shown. These grooves are equal in number to the number of the transverse rows
of keys, as shown and it is evident that each one of the wires in said channels
must be insulated to preserve its individual circuit. D is one of a bank or series
of magnets and may be placed at any convenient and proper place to perform any
desired function. d is a battery which is connected to the pan by any suitable
conductor, and M is the mercury electrode in said pan.
When the keys are placed in position in the chambers B' in the plate B and
secured therein, the plate is then secured in the top of the compartment A', and is
cemented or otherwise secured therein so as to prevent the escape of mercury or
other fluid electrode therein. The keys when in their normal position in the plate B
will not project into the mercury in the pan but must be depressed in order to
make electric contact therewith, as is apparent. When it is desired to introduce
mercury or other fluid conductor into the pan, the screw E is removed and the
fluid poured in through the vent holes e into the compartment A³, the cock a in
the channel or passage a is then turned and the fluid conductor will then pass into
the compartment A' under the keys or push buttons C. When it is desired to
move or carry the board around the mercury or other fluid conductor can be run
back into the storage compartment A", the cock a' closed and the screw E turned
down over the vent holes, when the machine be moved about without throwing
the mercury or fluid conductor in contact with the keys. It will be observed that
by this particular construction and combination the mercury or other fluid in the
compartment becomes the common electrode for one side of all the individual key
circuits. P is a mat or filler that has holes or openings through it. These holes or
openings are arranged in parallel rows and are connected on the under side of the
mat or filler by grooves or channels r, as shown in Figure 6. This mat or filler is
of the same form and size as the interior of the compartment A' and fits snugly
therein, and is used for the purpose of dispensing with as much mercury or other
conductor as possible, only so much being used as is necessary to establish a reliable
circuit. The holes or openings p in the mat or filler are made so as to be directly
under the stems of the keys, so that when the said keys are depressed the said
stems will enter the holes p and contact with the mercury therein. By use of a
mat of this character all splashing of the mercury from jars or other extraneous
causes will be prevented. It will be further observed that by reason of the
grooves or channels in the under side of the mat or filler that the withdrawal of

page_text: the mercury or other fluid conductor from the compartment A' will not be
interfered with, and it is to be observed further that by reason of these grooves
or channels the mercury therein will serve as a good conducting medium to each
and every hole or opening in the mat, thus putting each and every hole in electric
touch and contact with every other one in the mat or filler.
As above referred to the circuit closing device employed in my invention, is
more particularly described in connection with Fig. 7 which represents one push
button individually to form a continuous and uninterrupted metallic circuit, starting
from a binding post, placed into the hard rubber plate, while the other binding
post is in leading connection with the metallic pan and mercury therein, forming
the liquid electrode. K represents the receptacle or casing of cast iron or any
other suitable material, and is designed to hold a small quantity of mercury for a
purpose hereinafter described. H is a piece of hard rubber or other insulating
material and has a flange extending around the top thereof, as shown. This
hard rubber piece H fits tightly into the top of the receptacle K and is supported
therein by the flange around the top thereof, as shown. The said rubber
piece H has in it centrally thereof a cylindrical chamber or recess, and an opening
extending from said chamber through the top of the block, thus making a passage
through the said piece or block H, as shown. Into this chamber or recess is placed
a key or push button, the stem of which extends downward below the under side of
the hard rubber piece or block and into the receptacle K. When this stem is in
its normal position it rests just above the surface of the mercury in the receptacle K,
and only enters it when the button to which the said stem is secured is depressed.
The construction of this key is as follows: G is a suitable head made of any non-
conducting material, and is provided with a suitable flange or collar
for a purpose
hereinafter stated. In the under side or bottom of this button is secured a stem g',
preferably of Bessemer steel or copper wire. Surrounding this stem g' is a spiral
spring 93, the upper end of which is passed into an opening in the button and stem
and is tightly bound or secured therein by means of a pin 96, as shown. The lower
end of the spring is secured to a metallic collar 92 by ineans of a binding screw 9°,
or otherwise. This collar fits tightly in the lower end of the recess or chamber,
and is provided with a central opening of such size as to permit a free recipro-
cation of the stem g therethrough, and yet be sufficiently tight to prevent the escape
of the mercury into the chamber. On the under side of this collar is a binding
screw g for securing one end of a wire or other conductor h¹ which passes up
through a channel or opening in the hard rubber and is connected to a binding
post on the outer surface thereof. k is a binding post that passes through the
flange around the top of the rubber down into the wall of the receptacle K.
The key or push button is fitted into the chamber, the head fitting into the
opening in the top thereof and is prevented being pushed out by the flange which
limits its upward movement, the collar g² is fitted in the lower end of the chamber
as described, and forms the base upon which the key works. M is a suitable
quantity of mercury or other fluid electrode in the bottom of the receptacle. The
operation of this device is as follows:
A slight pressure on the head of the key causes the stem to enter the mercury
in the bottom of the receptacle, thus establishing a metallic circuit without joints
or sliding contacts. In this device the metallic circuit would be through the
binding post k, the walls or sides of the receptacle K, mercury M, stem g', pin gª,
spring 9, collar g² and conductor h¹ to the binding post h.
Push buttons of this form may be placed with their receptacles in rows side by
side, so as to form a keyboard, but I prefer to omit the binding posts, and to
arrange the push buttons, as shown in the drawings, all in one common plate of
hard rubber, by leading the wires connected to the push buttons through the
channels 6 formed in said plate, back to the operating magnets, and to unite the
receptacles into one base pan containing the liquid electrode common to all push
buttons, as described.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. In an electric key board for type writing and type printing machines the
combination of a base pan having two compartments, opening between said com-
partments, mercury or other fluid conductor in said pan, with banks or rows of
keys or push buttons, and conductors for said pan and keys as set forth.
2. In an electric key board for type writing and type printing machines, the
combination of banks or rows of keys, a non-conducting plate or support for said
keys, substantially as described, and conductors for said keys, with a base pan,
mercury or other fluid conductor therein, the said fluid being a common terminal
of all the key circuits of the key board, as set forth.
3. In an electric key board for type writing and type printing machines the
combination of a base pan having two compartments having communication through
a passage and a stop cock through said passage, mercury in one or both said com-
partments, with banks or rows of keys or push buttons, and conductors for said pan
and push buttons, as set forth.
4. A base pan or support for electric key boards having two compartments
therein and connected by suitable passage one compartment adapted to support and
hold the non-conducting key support, and the other provided with a top, vent and
stop therefor, as set forth.
5. A key board of electric contact or circuit closing keys in which a part of
each key forms one metallic electrode of the individual circuit to which it belongs,
the other electrode being a fluid electrode and forming a common terminal for the
return or other side of all the individual circuits of the key board, as set forth.
6. A key support for electric key boards consisting of a non-conducting plate
provided with parallel rows of chambers and grooves or channels in the plate
between the rows of chambers, as set forth.
7. A key support for electric key boards consisting of a non-conducting plate
provided with parallel rows of cylindrical chambers and channels or grooves in the
under side of the plate between the rows of the cylindrical chambers and parallel
with each other, as set forth.
8. A mat or filler for an electric key board having a mercury or other fluid
electrode, having rows of holes or openings therein, said holes or openings being
connected by grooves or channels in the under side of the mat running both
longitudinally and transversely thereof, or, longitudinally, or transversely, as set
forth.
9. In an electric key board for type writing and type printing machines the
combination of a base pan having two compartments having communication through
a passage, a stop cock therein, and mercury or other fluid conductor in one or both
said compartments, with banks or rows of keys or push buttons, and non-conducting
support for said keys or push buttons, as set forth.
10. In an electric key board for type writing and type printing machines the
combination of a base pan having two compartments, having communication
through a passage, stop cock in said passage, mercury or other fluid conductor in
one or both said compartments, and a vent and stop therefor in the rear com-
partment, with banks or rows of keys or push buttons, and non-conducting supports
for said rows of keys or push buttons, as set forth.
11. In an electric key board the combination of a base pan having two com-
partments, opening between said compartiments and rows or banks of keys or
push buttons, with magnets, and conductors connecting said keys or push buttons
and base pan, or fluid conductor therein, with said magnets, as and for the purpose
set forth.
12. The combination of an electric key or push button consisting of a head, a
stem secured therein, a spiral spring surrounding said stem and secured in an
opening in the upper end thereof, a collar surrounding said stem and to which the

page_text: lower end of said spring is secured, whereby the stem spring and collar become one
and the same unbroken and continuous metallic circuit, and a contact co-operating
with the lower end of the stem, as set forth.
13. A circuit closer of the character described consisting of an insulating support
or block, a chamber therein, a key in said chamber consisting of a head, a stem
secured therein, a spiral spring surrounding said stem and secured in said head and
the upper part of the stem a collar surrounding said stem and fitting in the lower
portion of the chamber and to which the lower end of the spring is secured, a
receptacle in which the insulating block is set and supported, mercury or other
fluid electrode in said receptacle, and suitable conductors, as and for the purpose
set forth.
14. An electric key or push button consisting of a head, a stem secured therein,
a spiral spring surrounding said stem and secured in an opening in the upper end
thereof, a collar surrounding said stem and to which the lower end of said spring is
secured, whereby the stem, spring and collar become part of one and the same
unbroken and continuous metallic circuit, as set forth.
Dated this 24th day of March 1894.
W. P. THOMPSON & Co.,
Agents.