Improvements in Railway Signalling Apparatus
Year: 1892

page_text: Date of Application, 7th Sept., 1892
Complete Specification Left, 7th July, 1893-Accepted, 7th Sept., 1893
NAL OLDULTICATION.
[Communicated from abroad by ARTHUR HENRY JOHNSON, of Rahway, in the
County of Union, State of New Jersey, one of the United States of America,
Engineer.]
Improvements in Railway Signalling Apparatus
1, LEICESTER BRADNEY STEVENS, of Darlington Works, Southwark Bridge
Road, in the County of Surrey, Engineer, do hereby declare the nature of this
invention to be as follows:-
""
This invention for improvements in railway signalling apparatus relates princi-
pally to slotting apparatus for controlling the action of railway signals in which
the concurrent action of several signalmen is required to take off a signal but
any one can at any time set it to danger; and consists essentially in inter-
posing in some part of the rod or other connections a vacuum or suction device
controlled by electromagnetic means in such manner that when the signal is set
to "danger" by any one of the several signalmen other than the one actually
working the signal an electric circuit enclosing a controlling maguet is broken
and the signalinau who actually works the signal is prevented from lowering it
to "line clear" until the electric circuit is again closed by the return of the
displaced signal lever or switch to its "line clear" position.
In one arrangement of signalling apparatus constructed according to this inven-
tion, a swaying lever, one end of which is connected to the signal lever, and the
other to the semaphore signal arm, is fulcrummed to a sliding rod or lever or
other suitable connection which is itself connected to a convex disc or piston
secured by a washer plate or otherwise to the centre of a circular diaphragm
of leather, india-rubber or other suitable flexible material secured at its outer
edge between the base of the vacuum apparatus and a clamping ring. The base
of the vacuum apparatus is dished concavely to correspond with the aforesaid
convex disc, so that when the said disc is pressed home it fits accurately the
correspondingly dished concave surface, the flexible diaphragm forming a separating
layer between them.
In the centre of the concave base is an aperture, which, when the two dished
surfaces are pressed together permits any air between them to escape. The
flexible diaphragm being secured to the disc by a plate in its central part only,
permits of a considerable amount of free motion in the said disc. The escape
aperture is provided with a valve normally held open by a spring but which can
be automatically closed by the armature of an electro magnet whose coils form
a part of an electric circuit which is closed when all the signal levers or switches
connected to the said signal are set to "line clear" and broken when either
lever or switch is set to "danger."
**
From the foregoing description it will readily be seen that when the signal
lever or switch other than the lever that actually works the signal is set to
danger" the escape valve is open and the disc or piston and concave base
separate and that the electric circuit which encloses the controlling electro
magnet is broken and will remain so until the displaced signal lever or switch
is reset to "line clear." In this condition the lever that actually works the
signal cannot take off the danger signal as any action will merely give motion
to the piston disc. When however the displaced lever or switch is reset to
"line clear," the act of so resetting it closes the electric circuit, which energizes
the electro magnet causing its armature to close the escape valve thereby
forming a vacuum between the disc and base of the vacuum apparatus. The

page_text: disc or piston this held by suction rigidly fixes the fulcrum of the before-
mentioned swaying lever and permits the action of the signal lever to be communi-
cated to the semaphore arm in the ordinary manner to set it to "line clear."
Instead of employing a swaying lever as herein before described I may attain
the same result by causing the action of the suction device to temporarily
disconnect the signal rod connections when either signal lever is set to "danger."
In the foregoing Specification I have only described my invention as applied
to "slotting apparatus but I do not confine its application to that only as it
can be used for any other railway signalling apparatus for which it is applicable.
Dated this 7th day of September 1892.
"
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Railway Signalling Apparatus.
1, LEICESTER BRADNEY STEVENS, of Darlington Works, Southwark Bridge
Road, in the County of Surrey, Engineer, 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 for improvements in railway signalling apparatus relates princi-
pally to "slotting" apparatus for controlling the action of railway signals in
which the concurrent action of several sigualmen is required to take off a signal,
but any one can at any time set it to danger"; and consists essentially in
interposing in some part of the rod or other connections a vacuum or suction
device controlled by electromagnetic means in such manner that when the signal
is set to "danger "by any one of the several signalmen, other than the one actually
working the signal, an electric circuit enclosing a controlling magnet is broken
and the signalman who actually works the signal is prevented from lowering it
to "line clear" until the electric circuit is again closed by the return of the
displaced signal lever or switch to its "line clear" position.
:-
In the accompanying four sheets of illustrative drawings
Figure 1 is a vertical section of one form of apparatus constructed according
to this invention.
Figure 2 is a plan of the same having the upper part removed and
Figure 3 is a sectional elevation of the upper part of the same.
Figures 4 and 5 represent side and front elevations respectively of my apparatus
fixed on to the signal post itself.
Figure 6 shows a sectional elevation of a modified arrangement of apparatus
in which the signal rod connections are temporarily disconnected when either
signal lever is set to "danger."
Figure 7 is a horizontal section on A. B Figure. 6.
Figure 8 is a sectional elevation and
Figure 9 an end elevation respectively of the escape valve controlling apparatus
. for the same.
.
In one arrangement of signalling apparatus constructed according to this inven
tion and illustrated in Figures 1, 2, and 3, a swaying lever a b, one end b'of
which is connected to the signal lever and the other to the semaphore signal
arm, through the usual weighted lever or its equivalent on the signal post or
elsewhere, is fulcrumed to a sliding rod c sliding in bearings d, which is itself
connected by the cranks ef and connecting rod g to a convex disc or piston
secured by a washer plate i to the centre of a circular diaphragm of leather,
india rubber or other suitable flexible material secured at its outer edge between
the base m of the vacuum apparatus and a clamping ring n. The base of the
vacuum apparatus is dished concavely to correspond with the aforesaid convex
disc so that when the said disc is pressed home as is the case when the signal

page_text: lever is in its "danger" position, it fits accurately the correspondingly dished
concave surface, the flexible diaphragm forming a separating layer between
them.
In the centre of the concave base is an aperture o which, when the two dished
surfaces are pressed together, permits any air between them to escape. The flexible
diaphragm being secured to the disc by a plate in its central part only, permits of
a considerable amount of free motion in the said disc h. The air escape aperture is
provided with a valve p normally held open by a spring q but which can be auto-
inatically closed by the armaturer of an electromagnets whose coils form a part of
an electric circuit which is closed when all the signal levers or switches connected
to the said signal are set to "line clear" and broken when either lever or switch is
set to "danger."
From the foregoing description it will be readily seen that when the signal lever
or switch other than the lever that actually works the signal is set to " danger
33
the escape valve p open, and the disc or piston and concave base are separated,
6
and that the electric circuit which encloses the controlling electromagnets is broken
and will remain so until the displaced signal lever or switch is reset to "line clear."
In this condition the lever that actually works the signal cannot take off the
danger" signal as any action will merely impart motion to the piston or disc h,
the semaphore arm being maintained at "danger" by the usual weighted lever or
its equivalent at the signal post or elsewhere. When however the displaced lever
or switch is reset to "line clear" the act of so resetting it closes the electric circuit,
which energizes the electromagnets, causing its armature to be attracted thereto
and to close the escape valve, thereby forming a vacuum between the disc and base
of the vacuum apparatus. The disc or piston h, thus held by suction, rigidly fixes
the fulcrum of the beforementioned swaying lever ab and permits the action of
the signal lever to be communicated to the semaphore arm in the ordinary manner.
to set it to "line clear."
*
In the arrangement shown in Figures 4 and 5 the apparatus is fixed directly on
to the signal post t. The suction apparatus is suspended by the bolts v from the
bracket to secured to the signal post whilst the swaying lever ab is fulcrumed on
to a link on the counterweighted lever y pivotted to the bracket and connected
to the suction disc rod a a. One arm a of the swaying lever is connected by the
rod ab to the signal arm the other arm being connected by the rod ac to the
weighted lever ad ae itself connected to the signal lever in the ordinary manner.
In the modified arrangement shown in Figures 6 to 9 inclusive instead of
employing the swaying lever ab as hereinbefore described, and shown in Figures 1
to 5 inclusive, the same result is attained by causing the action of the suction
device to temporarily disconnect the signal rod connections when either signal lever
is set to "danger."
On the end of the rod af, connected to the signal lever, is a crosshead ay
carrying two pulleys or rollers ahai the upper one a of which rolls along the
bar al connected to the signal through the usual weighted lever which maintains
the semaphore arm at "danger" when not otherwise operated, whilst the lower
one ai rolls along the bar am whose ends are pivotted to two parallel and equal
levers an an.
The bar a m is connected to the sucker disch by an open link a o
so that as the disc rises or falls the bar a m rises or falls also, being normally
pressed upwards by the weighted lever a p as will be readily understood. In the
upper bar al is a notch or recess a into which the pulley ah engages, so that
when the suction disc h is pressed home and the escape valve ar closed, the bar a m
being then in its highest position, the two rods al af move together. When how-
ever, either lever in connection with the electric circuit is set to " danger" the
electric circuit is broken, and, the valve ar opening, permits the suction disc to rise
or fall freely so that any motion of the rod af merely causes the roller ah to roll
along the bar al without operating it, and consequently without operating the
signal which together with the bar al is maintained at "danger" by the usual
weighted lever on the signal post or elsewhere. The air escape valve ar in this

page_text: case is operated by an armature lever as Figures 8 and 9 which is attracted to the
magnet at to close it when the signal levers other than the one in use are at "line
clear," and is guided by a guide bush a v and piston a w.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:―
1. In railway signalling apparatus controlling the action of the signals by means
of a vacuum or suction device interposed in the connections between the operating
lever and the signal and controlled by electricity substantially as described.
2. In railway signalling apparatus the employment of a disc or piston secured to
a flexible diaphragm, in combination with a dished base and escape valve controlled
by means of an electromagnet substantially as described.
3. In railway signalling apparatus the combination of the swaying lever a, b,
sliding bar c, cranks e, f, connecting link g, disc h, diaphragm l, base'm, and valve p,
substantially as described and for the purpose specified.
4. In railway signalling apparatus the electromagnet s, armature r, and valve p
in combination with base m, disc h and flexible diaphragm substantially as
described.
5. The arrangement and construction of railway signalling apparatus sub-
stantially as described with reference to Figures 1, 2, and 3 of the drawings.
6. The arrangement and combination of railway signalling apparatus sub-
stantially as described with reference to Figures 4 and 5 of the drawings.
7. In railway signalling apparatus, causing a break in the connections when a
signal lever is set to "danger," by means of a suction device substantially as
described.
8. In railway signalling apparatus the employment of an electrically controlled
suction device in combination with the link ao, bars af, al, crosshead
rollers a hai and counterbalanced bar am substantially as described.
ag,
9. The arrangement and combination of parts constituting my improvements in
railway signalling apparatus constructed and operating substantially as described
with reference to Figures 6 to 9 of the drawings.
Dated this 7th day of July 1893.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents