Improvements in and relating to Electrical Indicators.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in and relating to Electrical Indicators.
We, MERVYN WALTER STIKEMAN, Solicitor, of 57, Chancery Lane, and REGINALD
PAGE WILSON, Electrical Engineer, of 3, Prince's Mansions, Victoria Street, both in
the County of London, do hereby declare the nature of this invention to be as
follows:
Our invention relates to electrical indicators for bells, telephones, and such like
apparatus. In these as usually hitherto made and arranged one bell is common to a
set of indicators, and when any particular circuit is temporarily closed on ringing the
bell, a flag, disc, or other indicating device previously concealed is moved into view
and indicates the source of call, or in some cases the converse system is employed, a
flag or shutter normally visible being removed from view or caused to oscillate for a
short time. Both of these methods are unsatisfactory for sundry reasons. The usual
method of replacing such call-indicating device, except in the case of the pendulum
motion above referred to, consists of some mechanical arrangement of a plunger, lever,
pneumatic ball, or equivalent device operated by the hand of the attendant. This is
obviously an uncertain and clumsy method, inasmuch as it frequently happens that
the attendant fails to replace the displayed indicator, and hence before long two or
more, possibly all, of such indicators may be simultaneously in view, rendering it
impossible to ascertain by inspection from what source the last call came, and the
apparatus consequently becomes temporarily useless.
The object of our invention is to provide in substitution for any mechanical replacing
device dependent for its action upon an attendant, an automatic replacing device
operated by the electric current and adapted to act and replace the last-used indicator
with certainty and accuracy, by and simultaneously with the next call.
This object may be attained in a variety of ways, the details of which must
necessarily depend upon the design of the particular indicator movement to be fitted,
but an essential feature of our invention is that the closing of any call circuit at once
and automatically replaces any indicator then displayed, and only allows that one to
become and remain visible, whose circuit is then complete, and such one, or in the
case of two simultaneous calls then those two, become and remain displayed, and no
other or others.
In carrying out our invention we employ one or more solenoids connected in the
return circuit and adapted to act upon a modified form of any existing manual or
other replacer; this is provided in suitable position with a piece of iron the ends of
which will be normally presented to the poles preferably of a horseshoe electro-magnet
so that any impulse sent through any indicator must of necessity pass through these
magnet coils and actuate the replacing bars or equivalent devices. By similar means

page_text: also, rotatory motion may be imparted to oscillating replacing devices or the
necessary pressure applied to air balls in pneumatic replacers or otherwise as required.
In arranging the connections between the electrically actuated part. and the
indicating devices, we in some cases prefer to suspend the replacement rods so as to
normally rest against a stop or buffer at one end whereby they can move in one
direction only and thus coine readily to rest after operation; they return to their
normal position by their own weight so soon as the current ceases to flow and they
are released, having in the meantime returned all previously displayed flags to their
respective normal positions where they are held by some suitable catch.
Dated this 14th day of October 1896.
COMPLETE SPECIFICATION.
Improvements in and relating to Electrical Indicators.
We, MERVYN WALTER STIKEMAN, Solicitor, of 57, Chancery Lane, and REGINALD
PAGE WILSON, Electrical Engineer, of 3, Prince's Mansions, Victoria Street, both in
the County of London, do hereby declare the nature of this invention, and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
Our invention relates to electrical indicators for bells, telephones, and such like
apparatus. In these as usually made and arranged hitherto one bell is common to a
set of indicators, and when any particular circuit is temporarily closed on ringing the
bell, a flag, disc, or other indicating device previously concealed is moved into view
and indicates the source of call, or in some cases the converse system is employed, a
flag or shutter normally visible being removed from view or caused to oscillate for a
short time. Both of these methods are unsatisfactory for sundry reasons.
method of replacing such call-indicating device, except in case of the pendulum
motion above referred to, consists of some mechanical arrangement of a plunger, lever,
pneumatic ball, or equivalent device operated by the hand of the attendant. This is
obviously an uncertain and clumsy method inasmuch as it frequently happens that the
attendant fails to replace the displayed indicator, and hence before long two or more,
possibly all of such indicators may be simultaneously in view, rendering it impossible
to ascertain by inspection the source of the last call, and the apparatus consequently
becomes temporarily useless.
The object of our invention is to provide, in substitution for any mechanical
replacing device dependent for its action upon an attendant, an automatic replacing
device operated by the electric current and adapted to act and replace the last used
indicator with certainty and accuracy by and simultaneously with the next call.
The object may be attained in a variety of ways, the details of which must
necessarily depend upon the design of the particular indicator movement to be fitted,
but an essential feature of our invention is that the closing of any call circuit at once
and automatically replaces any indicator then displayed, and only allows that one to
become and remain visible, whose circuit is complete at the time, and such one, or in
the case of two or more simultaneous calls, then those two or more become and remain
displayed and no other or others.
We will describe our invention in reference to the accompanying drawings in which
Fig. 1 is an elevation of an arrangement for dealing with three signal discs; Fig. 2

page_text: illustrates an arrangement for bringing the replacing device to rest and automatically
preventing the operation of the signal discs except at the proper times.
Similar letters refer to similar parts.
The indicating devices are inclosed in a suitable closed casing with apertures in its
front side to permit the signal discs to be visible when required and in carrying out
our invention we employ signal discs, such for example as a, a, s shown in Fig. 1,
each operated by an electromagnet el, e, e respectively placed in convenient relation
thereto and connected in parallel in the circuit of a battery b. These magnets are
excited when the circuit is closed at cl c² or c³ and an electric current sent through
for the purpose of ringing the call bell and indicating the source of call by exposing
to view one or other of the discs. Each magnet has an armature a¹ a² or a³
respectively, mounted at one extremity of a rocking lever l, or which when
attracted oscillates the rocking lever on its centre and raises a catch n¹, n² or n³
formed upon the lever at the opposite side of its centre. These catches normally
engage with corresponding catches m³, m² or m³ fixed on the said discs st, s² or a3 and
then hold up the discs out of sight as at 3, but when any pair of catches are
disengaged as described, that disc will fall before the inspection aperture as shown
at 82 so that it can be seen by the attendant.
In order to replace these dises in their normal position out of sight at each
subsequent call and cause their catches m² m² m³ to be engaged by the corresponding
catches n 2 n³ a replacing device is ordinarily employed consisting of a bar
carrying on its outer side driving studs or pins In adapting our invention
to this arrangement this bar z is suspended within the casing by means of links such
as 25 and in such a manner that it can still, if necessary be moved horizontally
backward and forward by means of an ordinary replacing handle (such as is shown in
dotted lines on the right of Fig. 1). By means of our invention however the said
bar is automatically swung to the left each time one of the contacts c, cor e is made
by means of an electromagnet E placed in the return circuit 7, the return movement
to the right being effected by gravity. When this magnet E is excited by a current,
an armature A carried on the links 2' of the replacer is attracted, thus swinging the
har a suddenly upward to the left and causing one or other of the pins ³ to
strike sharply against the corresponding lower arms a' s or of any of the dises that
may at the time be in view. This motion causes the said disc or discs to oscillate
sufficiently to engage any pair m² n² or pairs of the disc and armature-lever catches
above referred to and their position becomes normal. When the circuit is broken the
armature A is released and the replacer swings to the right, impelled by gravity or
aided by a light spring if required.
Supposing a cireuit to be closed by the making of the contact of consequent on a
call, the magnet e² will then be excited and its armature a² attracted causing the
lever to oscillate and raise the catch a out of engagement with the disc-catch m²,
and the disc will be moved slightly from its upward and obscured position owing to
the action of its counterweight 2; it would then by its own weight fall into view
were it not temporarily prevented from doing so by the pin 22, which since the rod z
is in its extreme left hand position engages the arms 8 of the disc s². When the
current ceases to flow, the replacer is at once released and swings to the right then
allowing the dise 8 to fall into view as shown. In order to prevent the re-engagement of
the disc by its retaining catch when the circuit is broken and the armature a²
consequently released, the driving pins 2 2 2 are so disposed upon the bar z that
when the latter is in the extreme left hand position the catches m¹ m2 or m³ on the
discs shall have moved sufficiently to the left to avoid the catches n', n², n³ when they
descend. This position is shown by the disc s¹, the arm of which rests against the
pin 2, shown dotted.
It will be readily understood that what has been stated in explanation of the
operation of the disc a' is also applicable to each disc when two or more are simul-
taneously operated by the closure of two or more of the contacts c², c², c².
If one of the contacts c', c, c is closed whilst the corresponding disc is in view, the
corresponding driving pin s' s or a will cause the said disc to swing out of view, but

page_text: since the lever l, l'or l is attracted by its magnet, and consequently this corres-
ponding catch raised out of the path of the catch on the disc, the said disc cannot be
retained thereby but is maintained temporarily raised with the lower arm of its lever
resting against the pin a' s'or s' until the armature A is released by the magnet E,
then allowing the bar to swing to the right and the disc to fall again into view.
The replacing device is or may be provided with a stop for the purpose of causing
it to come readily to rest after operation, such a stop may be of any convenient kind
but we prefer to construct same as shown in Fig. 2 which also serves the purpose of
preventing accidental or abusive movement of the replacer. In this arangement an
electro-magnet E' is placed in the return circuit r to the right of the replacer z and
provided with a rocking armature A¹ which carries at its right hand extremity a
counterweight G for returning it to the operative position and at the opposite extremity
with a catch adapted to engage a corresponding spring catch at the adjacent
extremity of the bar z. This being as described suspended on the links when the
armature A is released by the electromagnet E the bar is arranged to swing through
a sufficient distance to the right to cause the catches f and f¹ to engage, and so retain
the bar z in inoperative position.
When the bar is disengaged from such inoperative position by a current passing
through the circuit and exciting the magnet E' the armature A is caused to rock upon
its centre and the said bar z is released and will have an initial movement to the left
imparted to it by gravity, such movement being continued and reinforced by the
action of the magnet E.
The bar must be so suspended that the deviation of the links from the
vertical on the side nearest the electro magnet E is greater than the deviation of the
links on the opposite side of the vertical, otherwise the momentum acquired by
the bar z on its release by the magnet E will not be sufficient to carry it through
the required distance to the left to ensure the engagement of the catches ff.
We do not limit ourselves to the exact constructional forms of our invention herein
described and illustrated by way of example, we may vary the detail or arrangement
of parts without departing from the spirit of the said invention in any way.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what we
claim is :-
1. An electrical indicator for bells, telephones, and such like apparatus in which
the closing of an electric circuit consequent on a call has the effect of simultaneously
operating a device for removing and replacing signals previously used and remaining
in view.
2. In an electric indicator such as above referred to, the employment in combination
with the signalling devices of an electromagnet. E energised by a battery at each
respective call, an armature for said magnet, attached to an automatic swinging
replacer such as 2, all arranged or adapted to operate substantially at the times and
in the manner herein set forth.
3. In an electrical indicator of the kind above referred to, connecting the signal-
removing and re-placing device with the armature of an electromagnet supplied with
current on and by the making of a call-contact, and arranging each signalling device
in such manner that its disc is liberated from its normally engaged catch on the
making of a contact by a call and is sustained out of engagement with said catch, but
allowed to move into view on the return of the said removing device to its normal
position, substantially as and for the purpose set forth.
4. An electrical indicator of the kind above referred to in which the making of a
signalling contact has the effect of releasing the signal-removing device from a stop
or catch adapted to bring the said device to rest and to retain it in inoperative
position as long as there is no current in the system, substantially as and for the
purposes set forth.
5. The construction and arrangement of the parts constituting our improved

page_text: electrical indicator substantially as described with reference to and shown in the
accompanying drawings, and for the purposes set forth.
Dated this 12th day of In. 1907
J. C. CHAPMAN,
Chancery Lane, London, W.C., Chartered Patent Agent.