IMPROVEMENTS IN THE CONSTRUCTION OF KEYS AND COMMUTATORS FOR TELEGRAPH INSTRUMENTS
Year: 1872

page_text: LETTERS PATENT to Ernest John Harling, of Westbourne Road,
Barnsbury, in the County of Middlesex, Electrical Engineer, for
the Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF KEYS AND
COMMUTATORS FOR TELEGRAPH INSTRUMENTS.”
Sealed the 10th June 1873, and dated the 13th December 1872.
PROVISIONAL SPECIFICATION left by the said Ernest John Harling
at the Office of the Commissioners of Patents, with his Petition,
on the 13th December 1872.
I, ERNEST JOHN HARLING, of Westbourne Road, Barnsbury, in the
County of Middlesex, Electrical Engineer, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF KEYS
AND COMMUTATORS FOR TELEGRAPH INSTRUMENTS," to be as follows:-
This Invention consists in certain improvements in keys and commu-
tators used in connection with telegraph instruments, whereby more
perfect insulation is obtained, and the keys enabled to work with less
pressure and with greater steadiness than heretofore. For the purpose

page_text: of rendering the key susceptible of lighter and more delicate pressure
than is requisite in instruments as ordinarily constructed, a flat ebonite
spring is placed over or under the metallic portion of the key. Thin
plates of ebonite are also employed to insulate the metallic portions of
the keys and commutators from the wooden stand, thereby avoiding the
creation of "short circuits," and securing all the advantages which
would be derived from the construction of the non-metallic parts of the
arrangements entirely of ebonite, and which would be too costly for
general adoption.
In order to impart steadiness of action to the key the same is provided ]
with a slot at a convenient part thereof, and through which slot a
vertical metallic guide plate which is fixed to the stand passes. Two
small brackets are attached to the key on the respective sides of the slot,
acting as guides to the guide plate, and upon the key being actuated its
motion is rendered steady and regular by the agency of the guide plate, 1
which effectually prevents any lateral movement and consequent derange-
ment of the key.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Ernest John Harling in the Great Seal Patent
Office on the 13th June 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ERNEST
John HarliNG, of Westbourne Road, Barnsbury, in the County of
Middlesex, Electrical Engineer, send grecting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of December, in the
year of our Lord One thousand eight hundred and seventy-two, in the
thirty-sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Ernest John Harling, Her special
licence that I, the said Ernest John Harling, my executors, administra-
tors, and assigns, or such others as I, the said Ernest John Harling, 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,

page_text: the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN THE CONSTRUCTION OF KEYS AND COMMUTATORS FOR TELEGRAPH INSTRUMENTS,"
upon the condition (amongst others) that I, the said Ernest John
Harling, 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 within six calendar monthis next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Ernest John Harling, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, that is to say :—
My said Invention consists in certain improvements in keys and
commutators used in connection with telegraph instruments, whereby
more perfect insulation is obtained, and the keys enabled to work with
less pressure and with greater steadiness than heretofore. For the
purpose of rendering the key susceptible of lighter and more delicate
pressure than is requisite in instruments as ordinarily constructed, a flat
ebonite spring is placed over or under the metallic portion of the key.
Thin plates of ebonite are also employed to insulate the metallic portions
of the keys and commutators from the wooden stand, thereby avoiding
the creation of "short circuits," and securing all the advantages which
would be derived from the construction of the non-metallic parts of the
arrangements entirely of ebonite, and which would be too costly for
general adoption.
In order to impart steadiness of action to the key the same is provided
with a slot at a convenient part thereof, and through which slot a
vertical metallic guide plate which is fixed to the stand passes. Two
small brackets are attached to the key on the respective sides of the slot,
and act as guides to the guide plate, and upon the key being actuated its.
motion is rendered steady and regular by the agency of the guide plate,
which effectually prevents any lateral movement and consequent derange-
ment of the key.
Having thus declared and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I would observe in
conclusion that what I consider novel and original, and therefore claim

page_text: as constituting the Invention secured to me by the said herein-before in
part recited Letters Patent is, the combination and arrangement of parts
and mechanism substantially as and for the purposes herein-before
described and set forth.
In witness whereof, I, the said Ernest John Harling, have here-
unto set my hand and scal, this Thirteenth day of June, in the
year of our Lord One thousand eight hundred and seventy-
three
Witness,
GEO. E. VAUGHAN,
54, Chancery Lane,
London.
ERNEST JOHN HARLING. (L.S.)