IMPROVEMENTS IN ELECTRIC BELLS
Year: 1885

page_text: COMPLETE SPECIFICATION.
PHILIP JOLIN of 2 Elmdale Rd Redland in the city and county of Bristol
Engineer do hereby declare the nature of my invention for IMPROVEMENTS IN
ELECTRIC BELLS and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
My invention consists in arranging a system of electric bells in such a way and
with such modifications of construction as will enable me to work a number of
trembling bells in series in one simple circuit. This has hitherto been impracticable
with trembling bells because as hitherto constructed such bells work by breaking
the circuit during their vibrations. I therefore modify the construction of the bells
so that no such break occurs in the main circuit of the bell, the break occuring
only in a demagnetizing shunt circuit.
Instead of winding the coils or bobbins of the electro magnets of the bells as is
commonly the practice with one wire only, and using a contact maker and breaker,
to interupt the current and thus magnetize and demagnetize the electro-magnet,
my improvement consists in having the coils or bobbins of the electro-magnet
wound with a double or divided coil so arranged and connected that the electric
current in traversing the two parts branches, or divisions, of the coil produces no
magnetizing effect untill the current in one part, branch, or division of the coil is
diminished, or stopped by the opening or rupture of that part, branch, or division.
To accomplish this end it is necessary that the windings of the two parts,
branches, or divisions of the coil shall be so wound round the bobbins, or cores and
so connected together, and to the circuit, that the currents in the two parts, branches,
or divisions, shall circulate arround the core in opposite directions. The combination
of such an electro-magnet with a suitably connected electric-bell is the essential
feature of my present invention as far as relates to the modification in construction.
The ends attained by the employment of this novel combination are two-fold
namely, firstly to enable me to arrange two or any larger number of bells in series
in one circuit and, secondly to prevent sparking at the place where the circuit
is opened or interrupted thereby enabling me to dispense with platinum tips, and
thereby cheapen construction.
In ordinary electric-bell electro-magnets the magnetization of the iron cores
is excited when the current is mado at the contact maker and breaker, and ceases
or is discharged when the current is broken and in consequence at the breaking of
the circuit there is a self induced or extra-current spark due to the discharge of
TD 017

page_text: the magnetization of the core or cores, In my improved method of winding with
two opposing sets of coils when both branches or windings of the circuit are closed
the core or cores remain unmagnetized, on breaking the circuit of either part,
branch, or division, the whole current is thrown round the other part, branch, or
division, of the circuit and the core is magnetized with out any spark of self-
induction occuring, When the circuit is again made through this part, branch, or
division the magnetization is discharged from the iron core because the current now
circulates in two opposing senses in the two parts, branches, or divisions but there
is again no spark for the circuit is closed before the discharge current or extra-
current of self induction is set up. The parts, branches, or divisions of the circuit
may be wound in several ways; the two wires may be wound on simultaneously
side by side in the same direction (but with reverse connections) or they may be
wound on separatly beside, or above, or between one another or the two windings
may be put on in alternate layers, or in alternate cells or sections along the core-
all that is necessary is that they shall be so wound and connected that the current
in one part, branch, or division completly neutralizes the magnetizeing effect of the
current flowing in the other part, branch, or division, otherwise the tendancy to
spark will not be neutralized.
Fig 1 in the accompanying sheet of drawings shows an ordinary trembling-
electric-bell having a single core electro-magnet wound according to my method,
Fig 2 shows a similar trembling electric-bell having a double core electro magnet
wound according to my method, Fig 3 shows a trembling electric-bell having the
electro magnets under the dome or gong itself, Fig 4 shows an ordinary single-
stroke bell wound according to my method, the same reference letters are used for
the same parts in all four figures and the direction in which the current flows in
the different divisions is shown by arrow-heads. E, E, E, E, is one part branch or
division of the circuit in these cases the one that is opened and closed or broken
and made, and D, D, D, D, the other part, branch or division of the circuit which
is always closed in the bell, T, T', are the two terminals, F¹ is a frame carrying
the core or cores F, and the spring S which in turn carries the armature A, this
spring is prolonged to S¹, S¹, below, or at the side of the armature so that when the
said armature is attracted it touches or rests upon the contact piece e¹ but when
the armature is at its normal position S¹ is clear of e¹ The circuits are connected
so that one end of the part branch or division D, D, D, D is attached to the
terminal T and the other end to the terminal T¹ that part, branch, or division being
closed in the bell, one end of E, E, E, E, is connected to T and the other end to e¹
in single core electro-magnet bells a connection from the frame F' armature A and
spring S being made to the terminal T¹, but when two electro magnets cores are
used the connections of E, E, E, E, are usually made as follows one end of E of one
core is connected to the terminal T Fig 2, the other end being connected to e¹, an
end of E of the other core is connected to the frame F' armature A and spring S
and the other end of E on this last core is connected to the terminal T, The
circuits being so arranged and connected that when the spring S¹, S¹, touches e¹
the current flows through D, D, D, D, and E, E, E, E, in opposite directions thereby
the current in one part, branch, or division, neutrilizes the effect of the current in
the other part branch or division.
The action is as follows when the armature A is held from the core or cores F,
by the spring S the core or cores are magnetized by the current flowing in D, D, D, D,
(the circuit out side the bell through the battery B being completed by closing the
push P,) and the armature A is attracted, but on the spring St, S₁, touching &¹ the
circuit in E, E, E, E, is completed the magnetization of the core or cores destroyed
and the armature released without any sparking. Fig 4 which represents a single
stroke bell has the circuits arranged thus, the circuit in the branch D, D, D, D is
permanently closed through the battery B when it is required to use the bell or it
may be closed at all times and a constant current battery used, the circuit E, E, E, E
which has an ordinary circuit interrupting key K in it is closed at the same instant
as the circuit D, D, D, D or is closed at all times when the bell is not actuated if
1

page_text: a constant current battery is used, to actuate the bell all that is necessary is to
depress the key K when the circuit in E, E, E, E is broken and the bell sounded;
the arrow heads in all cases show the directions in which the currents of electricity.
flow in the respective wires.
It will be obvious from the foregoing description that there is always a connected
circuit through one of the sets of windings of the electro magnets of the bells and
therefore if a number of bells are connected in series as shown in Fig 5 they can
all be actuated by one current from one battery or set of cells B, by means of one
single push P, each bell being independant of the rate of vibration of every other
bell on the circuit.
In conclusion I would observe that I do not claim the method of double winding
as applied to electro-magnets in general inasmuch as such electromagnets are known
in various departments of electrotechnics but what I claim as novel, and as my
invention and desire to secure by letters Patent is set forth in the following
claims.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
First The combination with a bell of an electromagnet having the circuit wound
with a double or divided coil or system of coils arranged for the purpose of
preventing the occurance of a spark at the place where the circuit is opened or
closed, and connected substantially as described and shown.
Second The combination in an electric circuit of two or more electric bells
having electromagnets of the type described, arranged in series in the circuit
substantially as described and shown.