IMPROVEMENTS IN ELECTRIC BELL INDICATORS
Year: 1884

page_text: I, HARRY. THORPE of 55 Theobald's Road, in the County of Middlesex, Electrical
Engineer, do hereby declare the nature of my invention for IMPROVEMENTS IN
ELECTRIC BELL INDICATORS to be as follows:-
The object of this invention is to simplify the construction of electric bell
indicators and thereby to reduce their cost of manufacture and at the same time
increase their efficiency and usefulness.
Supposing for example the indicator to be designed to receive indications from
four apartments, I provide, in an indicator box, four electro maguets set horizontally
side by side and parallel to each other. Each of these magnets I provide with an
armature of say a disc form which may be coloured red and in front of these discs
I mount semaphore discs coloured white which are severally held in place by a
catch formed on their respective armatures.
The armature of each magnet is carried by a lateral extension of the upper flange
of the bobbin of the magnet which flange is stamped out to a shape corresponding
with that of the armature end of the semaphore it being subsequently pierced
centrally for the electro magnet to protrude through it. The armature is made
elastic to yield to the attractive force of the magnet and to move from the magnet
when the attraction ceases. The screw which attaches the armature to its support
forms the fulcrum pin for the semaphore. Each semaphore is provided with an arm
which hangs in the path of a pin projecting laterally from an underlying sliding rod
which rod is retained in its normal position by means of a coiled spring.
The cover of the box is provided with a glass panel and a card or equivalent
opaque substance pierced with holes corresponding to the armatures is affixed to
the inner face of the glass panel. Below these holes is marked an indication of the
apartments with which the several electro magnets are in connection and from
which the signals for say the Servants' Hall are to be given or the armatures
themselves may carry these indications.
A knob projecting through the box and connected to the sliding rod provides for
imparting an endway motion to that rod and thereby causing the projecting pins to
strike the semaphore arms.
When the indicator is out of use the semaphores will all be raised and thereby
cover the red discs or armatures. Supposing however a signal is given from say
the "Parlour" the current set up in the circuit will cause the armature of the

page_text: electro magnet to be attracted and the retaining catch which that armature carries
being thereby drawn back the semaphore will drop by its own weight and expose
to view the red disc or armature ranged above or carrying the word "Parlour."
To prevent the semaphores moving with the armatures with which they are
respectively connected when the electro magnets are excited each bobbin flange is
provided with a pin corresponding to a hole made through the armature near its
edge. When therefore the armature is attracted if the semaphore follows it it will
strike against the projecting pin and be thrust free of the armature when it will
drop by its own weight and present the desired indication to view..
The duty of the servant in attendance will be to press in the knob of the sliding
rod before answering the summons and thereby to lift the semaphore into its normal
position. It will be obvious that the capacity of these instruments may be increased
to any desired extent and that two or more rows of magnets with the accessories
may be arranged in one and the same box or case to suit the requirements of Hotels
and other large establishments.
The armatures will in such cases conveniently carry numbers or letters to indicate
the rooms to which they pertain.
One great advantage offered by my improved indicating apparatus is the facility
of shewing at a glance to the attendant whence the signal has proceeded this is due
to the comparatively small area in which the semaphores are arranged.
D
M... 1004

page_text: I HARRY THORPE of 55 Theobald's Road, in the County of Middlesex, Electrical
Engineer, do hereby declare the nature of my invention for IMPROVEMENTS IN
ELECTRIC BELL INDICATORS and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :-
The object of this invention is to simplify the construction of electric bell
indicators, and thereby to reduce their cost of manufacture, and at the same time
increase their efficiency and usefulness.
For the purpose of avoiding unnecessary complexity, I have shewn in the
accompanying drawing my invention as applied to an electric bell apparatus having
four indicators.
Fig. 1 being a front view of the apparatus with the front screen removed.
Fig. 2 a sectional plan taken on the line 1, 2 of Fig. 1, and
Fig. 3 a front view of the apparatus with the screen in place.
In these Figures A A is the indicator box provided with a hinged cover which is
fitted with a glass panel carrying an opaque screen B, in which openings are made
corresponding in position with the semaphores and the indicators which underlie or
are covered by the semaphores.
The indicator box is provided with four electro magnets C set horizontally side
by side and parallel to each other. These magnets are made in the following
manner I take a core of soft iron of suitable length and braze or otherwise
secure to its opposite ends metal flanges c c*, forming the back flange c* with a
pair of lugs to receive screws for attaching the magnet to the back of the box A.
The other flange c I form with a lateral extension or arin to carry the armature and
the semaphore which will be presently explained, and between the two flanges
I wind the insulated wire upon the core of the electro magnet.
In front of each of these magnets is mounted an armature D, preferably of a disc
form, which may be white or of any desired color that will contrast with the
indication (whether a word or figure) painted thereon, and in front of these discs D,
I mount semaphore discs E, which may conveniently be colored red. These
semaphores are severally held in place by a catch formed on their respective
armatures.
The armature of each magnet is carried by a lateral extension of the front flange c
of the magnet, which flange is stamped out to a shape corresponding with that of
the armature and of the semaphore, it being subsequently pierced centrally for the
core of the electro magnet to protrude through it. The armature D is made elastic
to yield to the attractive force of the magnet, and to move from the magnet when
the attraction ceases. d is a screwed pin, which attaches the armature to its support,
and forms also the fulcrum for the semaphore. Each semaphore is provided with
an arm e, which hangs in the path of a pin f projecting laterally from an underlying
sliding rod F supported in guides f¹ carried by the back of the box. This rod F is
retained in its normal position by means of a coiled spring f³.
A knob f projecting through the box, and connected to the sliding rod F,
provides for imparting an end way motion to that rod, and thereby causing the
projecting pins to strike the semaphore arms e, and thereby lift the semaphores

page_text: into their raised position. Each semaphore is provided with a finger e¹, which as
the semaphore is raised, strikes a catch d' on the armature D, and sliding over it is
caught and held up by the catch, the elastic nature of the armature causing the
catch to yield and allow of the passage of the finger over it.
The coils of the several magnets are connected in the usual way with the circuit
wires, one end of each coil being connected to a common wire G leading to the
negative pole of the battery, and the other ends of the coils leading to the wires of
the apartment to which they respectively belong. In the drawing I have supposed
that the armatures carry the name of the apartment with which their magnets are
respectively connected, such as "Parlour," "Drawing Room," &c., and this may be
a convenient arrangement for small houses.
"
When the indicator is out of use, the semaphores will all be raised, and thereby
cover the disc armatures D. Supposing now that a signal is given from, say the
Parlour," the current set up in the circuit will cause the armature of the electro
magnet in connection with that apartment to be attracted, and the retaining
catch of that armature being thereby drawn back clear of the supporting finger e¹,
the semaphore will drop by its own weight, and expose to view the disc or
armature carrying the word "Parlour" as shewn at Figs. 1 and 3.
To prevent the semaphores moving with the armatures with which they are
respectively connected when the electro magnets are excited, the flange c of each
magnet is provided with a pin or projection to serve as a stop to the semaphore.
When therefore the armature is attracted if the semaphore follows it, it will strike
against the projection on the bobbin flange, and be held back from the armature.
The semaphore will then drop by its own weight, and present the desired indication
to view.
The duty of the servant in attendance will be to press in the knob of the sliding
rod before answering the summons, and thereby to lift the dropped semaphore into
its normal position.
To prevent the semaphores from rising too high, a stop pin c is provided on the
flange c of cach magnet, which pin standing in the path of the finger will arrest the
further upward motion of the semaphore.
It will be obvious that the capacity of these instruments may be increased to any
desired extent, and that two or more rows of magnets with their accessories may
be arranged in one and the same box or case to suit the requirements of Hotels and
other large establishments.
The armatures will under such circumstances, conveniently carry numbers or
letters to indicate the roonis to which they pertain.
One great advantage offered by my improved indicating apparatus is the facility
of shewing at a glance to the attendant whence the signal has proceeded; this is
due to the comparatively small area in which the semaphores are arranged.
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
The application to electric bell indicators of electro magnets constructed and fitted
as above described.