IMPROVEMENTS IN ELECTRO-MAGNETIC ANNUNCIATORS
Year: 1874

page_text: LETTER PATENT to Louis Finger, of Boston, in the County of Suffolk,
and State of Massachusetts, of the United States of America, for the
Ttion
TA
"
COMPLETE SPECIFICATION filed by the said Louis Finger at the Office
of the Commissioners of Patents, with his Petition and Declaration,
on the 19th May 1874, pursuant to the 9th Section of the Patent
Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LOUIS
FINGER, of Boston, in the County of Suffolk, and State of Massa-
chusetts, of the United States of America, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
ELECTRO-MAGNETIC ANNUNCIATORS," and have petitioned Her most Excellent
Majesty Queen Victoria to grant unto me, my executors, administrators,
and assigns, Her Royal Letters Patent for the same, and have made
solemn Declaration that I am the first and true Inventor thereof..
NOW KNOW YE, that I, the said Louis Finger, do hereby declare
the nature of the said Invention to be as follows, reference being had

page_text: and Figure 2, a plan :—
My main purpose in originating this device has been to avoid as much
as possible complexity of parts, and ensuring friction, and to provide an
annunciator for hotels and other buildings, which may be operated with
little expense for batteries, and which owing to its extreme simplicity
does not require skilled or experienced labor in producing it, and may
be to a great extent manufactured by machinery.
The construction of my present device consists in the employment of
a tilting rod or arm, bearing upon its upper end a card or plate having
engrossed upon its face a number or character indicative of the room or
apartment with which the device may be connected, such rod swinging
upon its lower part as a center, and being disposed near and to one side
of the core of an electro-magnet, in order that when the circuit is closed
the pole shall attract the rod, and the latter obtain such momentum as
to pass beyond the attractive power of the magnet, and bring up against
a stop suitably placed to receive it, the arm being returned to its normal
position by a rod or latch, as herein-after explained.
The Drawings accompanying this Specification represent at A a block
of wood, upon the upper part of which is fixed in a suitable manner an
electro-magnet G, one pole or wire a of which leads to the battery, and
the other, viz. b, to the apartment with which the annunciator is con-
nected, the block A and magnet being one of a large number disposed
within the office of the hotel or other structure in which the Invention is
to be used. B represents an upright rod or armature carrying at top a
flat plate or card a¹ placed in front of the magnet G, and with its lower
end pivoted to the block A, the pivot or turning point c of this rod
being slightly to the left of the center of the core b¹ of the magnet, in
order that instantly after passing by the center of the core it shall obtain
sufficient momentum to carry it beyond the influence of the magnet and
against a stop & secured to the block A, as shown, where it will remain
until returned by a horizontal rod or shipper C, which is supported in
suitable bearings attached to the block, and carrying a pin or stud e to
intercept and return the rod or armature B to its normal position against.
an initial stop f affixed to the block A to one side of the center of the
core 6'. A number or character of any suitable nature, whether the
number of a room or otherwise, is to be engrossed or placed upon the

page_text: card a¹; and when the armature B tilts into a position shown in dotted
lines in Figure 1 the card coincides with the window of the annunciator
which is to display it.
When the electric circuit is open the armature B rests idle against
the pin or stop f, and to one side of the iron core of the magnet, for the
reason that such stop is to one side of a vertical line struck from the
turning point of the rod.
When by a pressure upon a knob or otherwise a call is made from the
apartment with which the device is connected, and the electric current
thereby closed, the core 6¹ becomes a magnet, and attracts the armature B
toward it until the center of gravity of such armature preponderates
toward the magnet; but as such magnet does not possess sufficient power
to arrest the downward tendency and momentum of the armature the
latter passes by the magnet, and brings up against the second stop d
at such a distance from said magnet as to be unattracted by it.
The device, as above explained, is to be disposed within a case having
a series of small windows, one to each device, and each window is so
disposed with respect to the apparatus that when the card is in the
last-named position its number or character is visible, but when returned
to its normal position by pressure upon the rod C it retreats from sight.
The rod C has a coiled spring combined with it, as shown in the
Drawings, to return it to its legitimate position after it has set back the
rod or armature B.
First. A soft iron lever or armature pivoted in front of an electro-
magnet, and so adjusted with relation thereto that when the circuit is
closed the said lever will first by attraction of the magnet be tilted on
its axis or pivot to one side of the perpendicular to such an extent that
it will thereby by its own weight and momentum be caused to continue
said movement, and fall beyond the attracting power of the magnet, as
shown and set forth.

page_text: Third. The rod or shipper C, or its equivalent, in combination, with
the tilting arm or armature B and sign a¹ and stops d and f, substantially
as and for
purposes
stated.
Fourth. In combination the magnet, G, armature B, stops d, f, and
shipper C, substantially as and for the purposes stated.
In witness whereof, I, the said Louis Finger, have hereunto set my
hand and seal, this Second day of May 1874.