Improvements in Apparatus for Signalling between Police Stations and District Call Boxes.
Year: 1894

page_text: Date of Application, 4th Apr., 1894
Complete Specification Left, 3rd Jan., 1895--Accepted, 23rd Feb., 1895
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Signalling between Police Stations
and District Call Boxes.
+
We,
THE NATIONAL TELEPHONE COMPANY, (LIMITED) Oxford Court, Cannon
Street, London, E.C., and CHARLES EGGAR of 46 College Street, in the City of
Glasgow, Mechanic, do hereby declare the nature of this invention to be as
follows:-
This invention is a development of that described in the Specification of Letters
Patent No. 20144 of 1891 and it consists of improvements mainly in details
designed to simplify the signalling apparatus and render it more reliable, easier of
operation and less liable to derangement.
For the purpose of steadying the upper end of the gas pipe and burner within
the sliding shade the pipe is carried through a crosshead which is supported by
two, three or more rods or legs fixed in the lamp frame and through one of which
the pipe for supplying gas for the pilot light carried. The sliding tube which
carries the gallery for the lamp shade and which is fitted around the vertical gas
pipe leading to the lamp is actuated in its upward movement by weights as
described in the Specification before referred to, these weights being arranged to
balance the sliding tube and shade, but its movement is started by a helical spring
placed between the gas pipe and a loose tube at the lower end of the sliding tube
the spring bearing on shoulders formed on both. On pulling down the tube and
shade the spring is subjected to compression and the tube is held in its lowered
position by means of a collar on its lower end engaging with a spring catch on the
vertical arm formed on a bell crank lever corresponding to the lever formerly used
for operating the gas tap which tap is now replaced by a duplex valve hereinafter
described. This catch is freed by tilting the bell crank to permit of the sliding
tube being pressed upwards or raised by the coiled spring and counterbalancing
weights to raise the coloured shade to the position in which it surrounds the gas
flame for attracting the attention of a constable on duty in the neighbourhood of
the call box. The longer end of the bell crank is normally held to prevent its
tilting and releasing the sliding tube, by means of a catch upon a lever whose end
is engaged by the hooked end of an armature lever of an electro-magnet through
which an electric current is transmitted in communicating from the police station
to the call box which current passes through the electro-magnet and through a
spring switch forming terminals of the line and earth and with which a contact
piece on the lower sliding tube normally closes the circuit. Immediately upon the
transmission of this current and the release of the sliding tube the contact piece
rises out of contact with the spring switch and breaks the circuit so that the officer
at the district station may know that the signal shade has been raised whilst the
long arm of the bell crank drops into engagement with the catch lever ready for
the next call.
The citizen's key instead of operating the armature of the electro-magnet through
a pneumatic device as described in the before mentioned Specification, raises a
short rod which comes into contact with a spring switch forming terminals of the
line to earth through the electro-magnet and closes the circuit through the electro-
magnet which acts to release the bell crank and free the sliding tube, and display
the signal shade. The sliding tube with the lamp shade is pulled down by a cord
chain or wire connected directly to the tube and the gas supply for the main burner

page_text: is at the same time cut off. For this purpose a duplex valve seat is formed on the
gas pipe supplying gas to the main burner, an orifice being formed leading into a
valve casing from the horizontal gas supply pipe and a second orifice leading froin
the casing into the vertical pipe at whose upper end the burner is placed. These
two orifices are covered by a duplex valve disc of leather or like material carried
by a stem on whose upper end is a spring encased in a tube and carried by a cross
piece on the loose tube at the lower end of the sliding tube so that when the latter
is pulled down the gas supply is shut off; but when it is released the valve opens
to admit the gas supply to the burner whilst the upper side of the valve disc or a
separate disc on the same stem closes against a seat formed around the valve stem
and prevents escape of gas from the valve casing.
Dated this 3rd day of April 1894.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.
Improvements in Apparatus for Signalling between Police Stations
and District Call Boxes.
We, THE NATIONAL TELEPHONE COMPANY (LIMITED), Oxford Court, Cannon
Street, London, E.C., and CHARLES EGGAR of 46 College Street, in the City of
Glasgow, Mechanic, 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 :-
This invention is a development of that described in the Specification of Letters
Patent No. 20144 of 1891 and it consists of improvements mainly in details
designed to simplify the signalling apparatus and render it more reliable, easier of
operation and less liable to derangement.
On the accompanying drawings
Figure 1 is a vertical section of the call box showing the arrangement of the
signalling apparatus, and
Figures 2, 3 and 4 are views of the details of the apparatus comprising the
improvements referred to.
For the purpose of steadying the upper end of the gas pipe E and burner O1
within the sliding shade D¹ the pipe is carried as shown particularly at Figures 2
and 3 through a cross head B which is supported by two, three or more rods or
legs b fixed in the lamp frame C and through one of which the pipe A for
supplying gas for the pilot light A' is carried.
The sliding tube D which carries the gallery d for the lamp shade D' and which
is fitted around the vertical gas pipe E leading to the lamp ( is actuated in its
upward movement by the weights c as described in the Specification before referred
to, these weights being arranged to balance the sliding tube D and shade D' but its
movement is started by a helical spring d' placed between the gas pipe E and a
loose tube Fat the lower end of the sliding tube D the spring bearing on shoulders
formed on both. On pulling down the tube D and shade D' the spring d' is
subjected to compression and the tube D is held in its lowered position by means
of a collar d² on its lower end engaging with a spring catch g on the vertical arm gl
of a bell crank lever G corresponding to the lever formerly used for operating the
gas tap which tap is now replaced by a duplex valve hereinafter described. This
catch 9 is freed by tilting the bell crank G to permit of the sliding tube D being
pressed upwards or raised by the coiled spring d' and counterbalancing weights & to
raise the coloured shade D¹ to the position shown at Figure 3 in which it surrounds
the gas flame for attracting the attention of a constable on duty in the neighbour-
hood of the call box. The lower end of the bell crank G is normally held, to

page_text: prevent its tilting and releasing the sliding tube D, by means of a catch or notch i
upon a lever I whose lower end is engaged by the hooked end j of an armature
lever J of an electro magnet K through which an electric current is transmitted in
communicating from the police station to the call box which current passes through
the electro magnet K and through a spring switch k forming terminals of the liue L
and earth M and with which a contact piece f on the loose tube F normally closes
the circuit. Immediately upon the transmission of this current and the release of
the sliding tube D the contact piece ou the tube F rises out of contact with the
spring switch and breaks the circuit so that the officer at the district station may
know that the signal shade has been raised, whilst the long arm of the bell crank G
drops into engagement with its catch lever I ready for re-setting, which is effected
by drawing the tube D down until its collar d² engages with the spring g on the
bell crank G.
The citizen's key instead of operating the armature of the electro magnet through
a pneumatic device as described in the before mentioned Specification raises a short
rod N shown particularly at Figure 4 which comes into contact with a spring
switch n forming the terminals of the line L to earth through the electro magnet K
and closes the circuit through the electro magnet K which thereupon acts to release
the bell crank G and free the sliding tube D and display the signal shade D¹. The
sliding tube D with the lamp shade D' is pulled down by a cord, wire or chain O
connected directly to the tube D and the gas supply for the main burner O' is at
the same time cut off. For this purpose a duplex valve seat e, el, shown at Figure 2
is provided, which is formed on a tee-piece Q connecting the horizontal gas supply
pipe Qwith the vertical gas pipe E supplying gas to the main burner O³, an
orifice p being formed leading into a valve casing P from the horizontal gas supply
pipe and a second orifice p' leading from the casing into the vertical pipe E at
whose upper end the main burner O¹ is placed. These two orifices are covered by
a duplex valve disc p² of leather or like material carried by a stem p³ on whose
upper end is a spring which may be encased in a tube and carried by a cross
piece on the loose tube Fat the lower end of the sliding tube D, or as shown at
Figure 2 the spring may be situated between the outside of the valve casing and a
shoulder on the end of the stem, a projection f¹ being formed on a collar ƒ³
secured on the loose tube F so that when the sliding tube D is pulled down the
gas supply is shut off; but when it is released the valve opens to admit the gas
supply to the burner whilst the upper side of the valve disc p² or a separate disc on
the same stem closes against the seat e¹ formed on the upper side of the interior
of the valve casing and around the valve stem, and prevents the escape of gas
from the valve casing P.
4
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. Apparatus constructed, combined and arranged to operate substantially as
herein described for use in signalling between police stations and district call
boxes.
2. In apparatus for use in signalling between police stations and district call
boxes the device for guiding the upper end of the gas pipe adapted also to carry
the pipe for the pilot light substantially as described.
3. In apparatus for use in signalling between police stations and district call
boxes the combination with the balanced sliding tube D of the helical spring d
adapted to start the upward movement of the said tube when released substantially
as described.
4. In apparatus for use in signalling between police stations and district call
boxes the combination with the bell crank G of the catch lever I, armature
lever J, electro magnet K, switch k and contact piece arranged to operate
substantially as described.
5. In apparatus for use in signalling between police stations and district call

page_text: boxes the combination of the rod N on the door lock acted on by the citizen's key
and the spring switch n forming the terminals of the line through an electros
magnet operating to display the signal shade substantially as described.
6. In apparatus for use in signalling between police stations and district call
boxes the duplex valve constructed and actuated to control the gas supply
substantially as described.
Dated this 2nd dor of Jonu 1805
WALLACE FAIRWEATHER,
Chartered Patent Agent, 62, St. Vincent Street, Glasgow,
Agent for the Applicants.