Improvements in Fog Signalling Apparatus, chiefly applicable for Use on Railways.
Year: 1894

page_text: Date of Application, 11th Jan., 1894
Complete Specification Left, 10:h Oct., 1894-Accepted, 10th Nov., 1894
PROVISIONAL SPECIFICATION.
Improvements in Fog Signalling Apparatus, chiefly applicable for
Use on Railways.
J, ARTHUR HAMILTON COCHRANE, of Victoria Street, in the City of
Westminster, Engineer and Contractor, do hereby declare the nature of this
invention to be as follows :—
My invention relates to improvements in fog signalling apparatus_chiefly
applicable for use on railways, and one object of my improvements is to dispense
with the costly and dangerous system of fog signalling by means of detonators
placed on the rails by hand or otherwise.
I accomplish this object by the arrangement use and application of an audible
signal such as a fog horn under the control of the signalman in the cabin and
operated automatically to give the required signal by a blast of compressed air or
other elastic fluid released from a receiver by the passage of rolling stock over
the rails at any point desired.
A convenient form of apparatus according to my invention consists of an airtight
receiver or cylindrical casing which is sunk in the ground near one of the rails.
Within this receiver is a second cylinder bored to two diameters and in the portion
having the larger diameter are fitted two pistons and in the smaller diameter, one
piston, all three pistons being fixed on one piston rod which passes through a gland
and is jointed to a curved or otherwise suitably shaped lever or short rail pivoted
near and parallel to the main rail. The cylinder below the smaller piston and also
at a point between the limit of movement of the larger pistons is connected to a
reservoir containing compressed air or other elastic fluid. The cylinder at a point
below the upper of the two larger pistons when in the highest position has a port
opening into the receiver or outer casing and at a point above the said piston has a
passage leading by a pipe to the fog horn. The horn may be of any suitable type
and it has a mute as well as a sound outlet for the compressed air which can be
directed into either outlet by means of a valve under the control of the signalman
in the cabin and arranged to be turned whenever the ordinary semaphore or other
signal lever is pulled.
In clear weather the curved rail or short lever lies below and out of reach of
any passing wheel; but in dark or foggy weather as soon as compressed air is
admitted to the cylinder below the small piston it raises the piston rod and the
curved lever into a position where it will be depressed by any wheel passing over
the adjoining line. Simultaneously the air admitted into the cylinder between the
two larger pistons flows through the port into the receiver which is thus charged
with compressed air. When a wheel depresses the curved lever the piston rod and
piston are forced down against the resistance of the compressed air supply and the
upper of the larger pistons passing to the under side of the port shuts off the
connection between the compressed air supply and the receiver and puts the latter
in direct communication with the passage leading to the horn; the charge of air
compressed in the receiver instantly rushes along the passage and escapes either
through the sound or mute outlet of the horn according to the position which the
valve occupies, this position being determined by the position of the semaphore or
other visible signal. For example, if the visible signal be at "danger" then the
air would escape through the sound outlet and blow the horn; but if ou the other
hand the visible signal were at "line clear" then the air would escape through the
mute outlet without giving any audible signal.

page_text: It will be readily understood that when the curved lever has been depressed by a
passing wheel the compressed air in the receiver acting on the larger area of the
top piston overcomes the action of the compressed air supply on the smaller area
of the bottom piston and consequently all the pistons and the curved lever remain
down until the charge of compressed air from the receiver has escaped through
either the sound or mute outlet of the horn; then the curved lever is at once raised
again and the apparatus re-set by the air pressure acting on the smaller piston.
The length of time during which the signal is sounded can be regulated by the
size of the receiver and also of the valve of the horn; and the horn can be made
to give one long blast or a series of short intermittent blasts and so indicate which
line is blocked.
The pressure of air can be maintained in the supply reservoir by a hand pump
worked by the fogman or by any convenient motor.
Dated this 10th day of January 1894
H. B. BARLOW & GILLETT,
Agents for Applicant.
COMPLETE SPECIFICATION.
Improvements in Fog Signalling Apparatus, chiefly applicable for
Use on Railways.
I, ARTHUR HAMILTON COCHRANE, of 5 Victoria Street, in the City of
Westminster, Engineer and Contractor, 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 :-
My invention relates to improvements in fog signalling apparatus chiefly
applicable for use on railways, and one object of my improvements is to dispense
with the costly and dangerous system of fog signalling by means of detonators
placed on the rails by. hand or otherwise.
I accomplish this object by the arrangement use and application of an audible
signal such as a fog horn under the control of the signalman in the cabin and
operated automatically to give the required signal by a blast of coir pressed air or
other elastic fluid released from a receiver by the passage of rolling stock over the
rails at any point desired.
And in order that my invention may be fully understood and readily carried
into effect I will describe the accompanying sheet of drawings reference being had
to the figures and letters marked thereon.
Fig. 1 is a side elevation, partly in section, and Fig. 2 is a plan view of the chief
portion of my improved fog signalling apparatus applied to a railway.
In these views, a designates one of the main line railway rails resting upon
sleepers 6 which support longitudinal bars c and transverse bars d; to these bars is
secured an airtight receiver or cylindrical casing e which is sunk in the ground
near the rail a. Within the receiver e is a second cylinder bored to two
diameters and in the portion having the larger diameter fare fitted two
pistons gg and in the smaller diameter one piston g' all three pistons being
fixed on one piston rod g which passes through a gland hand is jointed to a curved
or otherwise suitably shaped lever i pivoted to a bracket j carried by a transverse
bar d' so that the lever i lies parallel with and close to the main rail a. A passageƒ³
made in the side of the cylinder fis connected to the smaller cylinder f* at a point
below its piston y* and a passage connects the passage to the larger cylinder,
at a point between the limit of movement of the larger pistons g' g³ fitted in it and
this passage is connected by a pipe, not shown, to a reservoir containing
compressed air or other elastic fluid, as indicated by arrows. The cylinder at a
point below the upper piston g' when in the highest position and above it when in
the lowest position is connected by a port to the receiver or outer casing e and
1

page_text: in the cylinder ƒ at a point above the piston g` is a porty leading to a signal norn,
not shown.
The signal horn may be of any suitable type and it has a mute as well as a sound
outlet for the compressed air which is directed into either outlet by a three way or
other suitable valve, not shown, under the control of the signalman in the cabin and
which is arranged to be turned by suitable connections whenever the ordinary
semaphore or other signal lever is pulled.
In clear weather when the apparatus is not required the connection between the '
reservoir of compressed air and the cylinders f f is cut off by a suitable valve,
the weight of the curved lever i would push the piston rod g and its pistons to their
lowest position so that the said lever would be below and out of reach of any
wheel passing on the rail a; but in dark or foggy weather the signalman in the
cabin would, by suitable connections, open the valve and admit compressed fluid
from the reservoir into the passages the fluid would then act upon the piston g
and raise it and the curved lever i into the position shown in Fig. 1 where it would
be depressed by any wheel passing over the ordinary rail a. Simultaneously the
air admitted into the cylinder f through the port f* between the two pistons g¹g
flows through the port into the receiver e which thus becomes charged with
compressed air.
When a wheel runs over the rail a it depresses the curved lever i, and the piston
rod 9 and pistons 9¹ g³ 9³ are forced down against the resistance of the compressed
air and the upper piston y passing to the under side of the port f* shuts off the
connection between the compressed air supply and the receiver e and puts the latter
through the port f³ in direct communication with the passage f leading to the
signal horn; the charge of air compressed in the receiver e instantly rushes along
the passage and escapes either through the sound or mute outlet of the horn
according to the position which the three-way valve occupies, this position being
determined by the semaphore or other visible signal.
For example, If the visible signal be at "danger" then the valve would, by
its connection with the signal, be opened so as to allow the compressed air to
escape through the sound outlet and blow the horn, but, if, on the other hand, the
visible signal were at "fine clear" then the valve would be turned so as to allow
the compressed air to escape through the mute outlet without giving any audible
signal.
It will be readily understood that when the curved lever i has been depressed by
a passing wheel the compressed air in the receiver e acting on the larger area of
the top piston g¹ overcomes the action of the compressed air supply on the smaller
area of the bottom piston g³ and consequently all the pistons g¹g and the curved
lever i remain down until the charge of compressed air from the receiver e has
escaped through either the sound or mute outlet of the horn; then the curved
lever i is at once raised again by the pressure of air admitted through the passage ƒ¨*
acting on the smaller piston g³ and the apparatus is reset automatically.
The length of time during which the signal is sounded can be regulated by the
size of the receiver e and also of the valve of the horn.
In the case of large stations or at junctions where several such audible signalling
apparatus were employed, the horns could be made to sound a different note and
thereby indicate the line which is blocked.
The pressure of air can be maintained in the supply reservoir by a hand pump
worked by the fogman or by any convenient motor.
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 :-
In a railway fog signalling apparatus—
1. The combination of a receiver or cylinder within which is placed a second
cylinder of two diameters, a piston rod connected to a pivoted rail or lever placed

page_text: of the second cylinder and ports and passages as described for supplying air under
pressure from a reservoir to the cylinders and for allowing a charge of compressed
air to escape from the receiver to a signal horn whenever the pivoted rail or lover
is depressed by a passing wheel, all arranged and operating substantially as and for
the purposes herein set forth.
2. The general construction combination and arrangement of parts embodying
my improvements in fog signalling apparatus substantially as and for the purposes
herein described with reference to the drawings annexed.
Dated this 9th day of October 1894.
H. B. BARLOW & GILLETT,
17, St. Ann's Square, Manchester, Agents for Applicant.