IMPROVED ELECTRO-MAGNETIC APPARATUS FOR OPERATING CLOCKS OR TIMEKEEPERS
Year: 1874

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PROVISIONAL SPECIFICATION left by Henry Brown Greenwood at the
Office of the Commissioners of Patents, with his Petition, on the
9th September 1874.
I, HENRY BROWN GREENWOOD, of Minson Road, South Hackney, in
the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVED ELECTRO-MAGNETIC APPARATUS FOR OPERATING CLOCKS
OR TIMEKEEPERS," to be as follows:-
My Invention relates to apparatus whereby any desired number of
clocks or timekeepers placed in an electric circuit connected with the said
apparatus may be operated and made to keep accurate time.
It must be understood that the clocks or timekeepers operated by
my apparatus are without the usual clockwork mechanism, except the
motion wheels which give the proper relative movements to the two
hands.
The operative mechanism which I employ consists of an electro-

page_text: magnet and battery, a balance wheel and lever, and a device for making
and breaking the circuit of the said battery.
The said balance wheel has a coiled spring, and is fitted to oscillate on
a pivot like the balance wheel of a watch. The lever is forked and
takes hold of a pin on the said balance wheel. The said lever is fitted
to vibrate upon a pivot and has a small dise surrounding the said pivot ;
this disc is fitted with a piece of platinum or other conductor, and a
piece of ebonite or other non-conductor of electricity. The said disc is
arranged in close proximity to a small metal disc fitted to turn or oscillate
upon a pivot pin connected through a wire with, the positive pole of a
battery. The disc on the lever cannot make contact with this second
disc, except through a small pin on the latter; this pin as the said
lever oscillates, touches alternately the platinum and ebonite of the first
disc, and thereby alternately makes and breaks the circuit. Each time
the circuit is made the electro-magnet pulls down the lever, which
gives an impulse to the said balance wheel. At the moment the said
lever touches the electro-magnet the ebonite or non-conducting portion
of the disc on the said levers meets the contact pin on the other disc.
The circuit is then immediately broken and the balance wheel and lever
recoil, this action being continued as long as the electric current is
supplied from the battery. I provide the second disc with a friction
spring to prevent its turning too far round on its pivot.
In combination with the above described apparatus I employ a ratchet
wheel and spring pawl, actuated by another electro-magnet included in
the same circuit as the first electro-magnet. Each time the said circuit
is made as above described, this spring pawl is drawn up to its electro-
magnet, and each time the circuit is broken the said pawl is depressed
by its spring, and acting on the ratchet wheel turns it one tooth or notch
forward. Another pawl arranged in combination with the said wheel
prevents its turning backward. The said wheel is provided with a .stud
or pin, which, once in each revolution of the said ratchet wheel, comes
in contact with a small spring or tongue of brass or other suitable metal,
and closes the circuit wherein the clocks or timekeepers are placed.
Each of the said clocks is provided with an apparatus consisting of a
magnet, spring pawl, and ratchet wheel similar to that above described;
this ratchet wheel is fixed on the spindle of the long hand of the clock,

page_text: and each time the said circuit is made and broken the said ratchet
wheel is moved one tooth forward.
.
The motion of the short hand is obtained by the usual motion wheels
from the spindle of the long hand.
By providing cach clock with an extra set of the said apparatus it can
be made to strike the hours, half-hours, or quarters, as desired.
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