IMPROVEMENTS IN ELECTRIC BELL AND SIGNAL APPARATUS."
Year: 1882

page_text: LETTERS PATENT to Thomas Robert Brailsford of Trinity Square Tower Hill
in the City of London for an Invention of "IMPROVEMENTS IN ELECTRIC
BELL AND SIGNAL APPARATUS."
PROVISIONAL SPECIFICATION left by the said Thomas Robert Brailsford
at the Office of the Commissioners of Patents on the 8th September 1882.
THOMAS ROBERT BRAILSFORD of Trinity Square Tower Hill in the City of
London "IMPROVEMENTS IN ELECTRIC BELL AND SIGNAL APPARATUS
"
This Invention relates more especially to electric bell apparatus in which the
bell can be rung from any one or other of a number of rooms or places and in which
on the ringing of the bell one or other of a number of indicators has at the same
time to be moved to indicate from which room or place the bell has been rung-
but the invention is applicable to signal apparatus used for other purposes.
At the present time all systems of indication require a separate electro magnet
for each indicator and another for the bell. By my invention one electro magnet
is made to suffice both to indicate from which room or place the bell has been rung
and also to ring the bell.
This I effect as follows; I fix the electro magnet to a block capable of sliding up
and down in a vertical tubular case.
When the block is at the top of the case it is held up by a catch-the catch has
an arm extending from it which carries a soft iron armature just in front of the
poles of the magnet in order that when the armature is attracted it shall release
the catch and allow the block to drop to the bottom of the case.
As the block so descends the poles of the magnet are carried past a series of
other soft iron armatures situated at distances apart one below the other.
If a current is passed through the coils of the magnet when it is opposite to any
one or other of these armatures the armature is attracted and moves a distance
towards the magnet and in doing so shifts a signal or indicator which is connected
to it and so indicates which armature has been so moved.
When the block reaches the bottom of the case the poles of the magnet come

page_text: opposite another armature by means of which the bell is to be rung and an
electric current being then caused to pass through the coils of the magnet the bell
is rung and (in the case of a continuous signal being desired) continues to ring
until the block is lifted up again to the top of the case. In some cases the falling
of the block might be made to complete a circuit through the magnet coils of a
separate bell apparatus instead of the magnet on the block being made to ring
the bell.
From each room an insulated wire is led to the basement or other part of a
building in which the apparatus above described is placed.
In each room there is as is usual a contact apparatus by which such wire can
be coupled to a main wire from one pole of a battery. The ends of all the wires
are led into the the top of the casing of the apparatus.-When the block is at the top
of the case a metallic comb or brush or other suitable contact mechanism carried
by the block is in contact with each of the wires the comb or contact is also
coupled to one end of the coils of the electro magnet-this end of the coils of the
magnet is also coupled to a metallic contact spring which when the block falls
comes in succession against a series of metallic contact plates fixed at distances
apart one below the other. There are as many such contact plates as there are
wires from the several rooms and each plate is coupled to one or other of the
wires one plate to each wire.
The other end of the coils of the magnet is coupled to another contact spring
carried by the block and this spring always rests against a metallic rod or wire
which extends from top to bottom of the case and is coupled to the other pole of
the battery.
In this way whenever any one or other of the wires leading from any of the
rooms is by the pushing in of a press button or by other contact apparatus coupled
up with the main wire from the battery a current will pass through the coils of the
magnet-the magnet will attract the armature attached to the catch and will
release the catch-the block will drop and when the contact spring it carries
passes over the contact plate which is in connection with a branch of the same wire
through which the current previously passed the current again passes and the
armature which is then opposite to the poles of the magnet is attracted and the
signal in connection with that armature is thereby moved.-The speed at which
the block is allowed to descend can be controlled by suspending the block by a
cord which is passed over a pulley and has a counterbalance weight attached to it.-
It is not necessary that the electro magnet should as above described be made to
travel downwards or in a straight line whenever the bell has to be rung it might
be arranged to move in a circular course and act in the same manner.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Robert Brailsford in the Great Seal Patent Office on the
8th March 1883..
THOMAS ROBERT BRAILSFORD of Trinity Square Tower Hill in the City of
London "IMPROVEMENTS IN ELECTRIC BELL AND SIGNAL APPARATUS
"
This invention relates more especially to electric bell apparatus in which the
bell can be rung from any one or other of a number of rooms or places, and in
which on the ringing of the bell, one or other of a number of indicators has at the
same time to be moved, to indicate from which room or place the bell has been
rung, but the invention is applicable to signal apparatus used for other purposes.
At the present time all systems of indication require a separate electro magnet
for each indicator and another for the bell. By my invention one electro magnet
is made to suffice both to indicate from which room or place the bell has been rung,
and also to ring the bell.
This I effect as follows:-I fix the electro magnet to a block capable of sliding
up and down in a vertical tubular case. When the block is at the top of the case
it is held up by a catch; the catch has an arm extending from it which carries a
soft iron armature just in front of the poles of the magnet, in order that when the
armature is attracted it shall release the catch and allow the block to drop to the
bottom of the case.
If a
As the block so descends, the poles of the magnet are carried past a series of
other soft iron armatures, situated at distances apart one below the other.
current is passed through the coils of the magnet when it is opposite to any one or
other of these armatures, the armature is attracted, and moves a distance towards
the magnet, and in doing so shifts a signal or indicator, which is connected to it,
and so indicates which armature has been so moved.
When the block reaches the bottom of the case, the poles of the magnet come
opposite another armature, by means of which the bell is to be rung, and an electric
current being then caused to pass through the coils of the magnet, the bell is rung,
and (in the case of a continuous signal being desired) continues to ring until the
block is lifted up again to the top of the case. In some cases the falling of the
block might be made to complete a circuit through the magnet coils of a separate
bell apparatus, instead of the magnet on the block being made to ring the bell.
From each room an insulated wire is led to the basement or other part of a
building in which the apparatus above described is placed. In each room there is,
as is usual, contact apparatus by which such wire can be coupled to a main
wire from one pole of a battery. The ends of all the wires are led into the top of
the casing of the apparatus. When the block is at the top of the case a metallic
comb or brush or other suitable contact mechanism carried by the block is in
contact with each of the wires; the comb or contact is also coupled to one end of
the coils of the electro magnet; this end of the coils of the magnet is also coupled
to a metallic contact spring which when the block falls comes in succession against
a series of metallic contact plates fixed at distances apart one below the other.
There are as many such contact plates as there are wires from the several rooms,
and each plate is coupled to one or other of the wires, one plate to each wire.
The other end of the coils of the magnet is coupled to another contact spring
carried by the block, and this spring always rests against a metallic rod or wire,
which extends from top to bottom of the case and is coupled to the other pole of.
the battery.
In this way whenever any one or other of the wires leading from any of the

page_text: rooms is, by the pushing in of a press button or by other contact apparatus, coupled
up with the main wire from the battery, a current will pass through the coils of
the magnet; the magnet will attract the armature attached to the catch, and will
release the catch; the block will drop, and when the contact spring it carries
passes over the contact plate, which is in connection with a branch of the same
wire through which the current previously passed, the current again passes, and
the armature, which is then opposite to the poles of the magnet, is attracted, and
the signal in connection with that armature is thereby moved. The speed at which
the block is allowed to descend can be controlled by suspending the block by a
cord, which is passed over a pulley, and has a counter-balance weight attached to
it. It is not necessary that the electro magnet should as above described be made
to travel downwards or in a straight line whenever the bell has to be rung, it
might be arranged to move in a circular course and act in the same manner.
Alternatively the armatures may be made to travel in front of the fixed electro
magnet, moving rectilineally or otherwise and operated by a hanging weight. The
successive completion of the different circuits will be made as herein-before
specified, the relative movements of the magnet to the indicative armature and to
the bell being the same.
In order that my invention may be the better understood, I now proceed to
describe the same with regard to the drawings hereto annexed, reference being had
to the figures and letters marked thereon.
Figures 1 and 2 show my arrangement with a falling electro-magnet, the
actuation of the armature indicators being the same in each, the chief distinction
being in the form of the releasing detent and in the shape of the casing.
Like letters refer to similar parts in each of these two figures.
M is the electro-magnet fixed to a carrier or block C. This carrier or block
slides up and down the guide G Figure 2 or tube G Figure 1
In Figure 1 the block and magnet is suspended by the notched rod m held by
the lever detent B, which is provided with a soft iron armature b and is thus
attracted to the magnet M when the circuit is completed, releasing the magnet and
block MC, and allowing them to fall.
In Figure 2 the magnet carrier C (shown falling) rests upon and falls into a
notch g upon the guide and is drawn out therefrom and released by the mutual
attraction of the electro magnet M and the fixed armature A when the circuit is
completed.
The electro magnet M with its carrier C then falls to the bottom of the case, its
velocity being modified by the re-action of the balance-weight W.
D represents diagrammatically any suitable galvanic battery and the different
room circuits and bell pushes p. p. p. therein.
From the several room circuits, insulated wires Q are carried to spring tongues q
mutually insulated, at the top of my apparatus and also alternative circuits n n n
to studs in the back of my apparatus, so placed that a spring on the electro-magnet
successively makes contact with them as it falls.
When the electro-magnet is suspended in position as shown in the drawing
Fig 1 the pressure on any of the bell pushers p. p. p will close the electrical circuit
from the battery D through one of the circuits Q to the spring finger q thence by
the contact bridge O, around the electro magnet to the constant conducting guide G
through the carrier C, thence, through the bell spring R, to the set screw S, and
thus back to the other pole of the battery.
The completion of this circuit releases the electro magnet M, which on falling
breaks circuit from the spring fingers g, but restores the circuit as the spring L
comes in contact with either of the studs n n n, which may be in closed, circuit
by one of the bell-pushers. At such a point the electro-magnet recovers its
magnetism, and attracting that one of the moving or tumbling indicator labels
T. T. T. which at the time is opposite to it, gives indication of the room from which
the signal was given.
When the magnet reaches the bottom of the case the spring L is in contact with

page_text: the stud n', the termination of a permanently closed circuit. The recovered mag-
netism of the electro-magnet will then operate; by the vibration in the usual way
of the spring armature R, an ordinary electric bell V, which will continue to give
warning until the attendant raises the electro-magnet to its former position, thereby
also tilting back to its former position any displaced indicator label. To effect the
ringing of a bell the falling electro magnet can either release a spring and close an
independent bell circuit either at the top or bottom of the case. Should a
temporary bell signal only be required, a bell circuit may be closed only during
the fall of the electro-magnet, by a spring pressing on a conductor of suitable
length. Alternatively the bell may be rung mechanically as the electro-magnet
falls by a tilt hammer and a toothed wheel upon the rotating drum over which the
cord passes.
Having now described and ascertained the nature of my said invention and the
manner in which it may be carried into effect, be it known that what I consider
novel and desire to protect by Letters Patent is :-
First. In an electric bell and signal apparatus, the combination of a single electro
magnet, electrical circuits, and a series of armatures, the magnet moving successively
over the said armatures, or vice versa, to effect any required indicative movement
of the armatures, substantially as set forth.
Second. In an electric bell and signal apparatus, the combination of a falling
electro-magnet making circuit contacts as described with a series of indicative
armatures, and a bell armature, to effect the movement of an indicative armature in
any required closed circuit and to ring the bell as a warning thereof, substantially
as set forth
In witness whereof I the said Thomas Robert Brailsford have hereunto set my
hand and seal this eighth day of March in the year of our Lord One
thousand eight hundred and eighty-three.
Witness:
JOHN. C. FELL
of the firm Fell & Wilding
Patent Agents
23 Rood Lane E.C.
T. R. BRAILSFORD (L.S.)