Improvements in or connected with Means or Apparatus for Operating and Controlling the Switches and Signals of Railways.
Year: 1892

page_text: Date of Application, 7th Mar., 1892-Accepted, 7th May, 1892
COMPLETE SPECIFICATION.
Improvements in or connected with Means or Apparatus for
Operating and Controlling the Switches and Signals of Railways.
I, CUTHBERT ELLISON CARR of Hedgeley, Alnwick, in the County of
Northumberland, 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 :-
My invention relates to switches which are operated by fluid pressure such as
are described in the Specifications of prior Patents granted to me No. 9150 dated
22nd June 1888 and No. 6859 dated 3rd May 1890 and in the Specification of my
application for Letters Patent No. 3131 dated 20th February 1891 and has for its
object to cause the fluid on its return flow from the cylinders which operate the
switches, to operate means whereby the signalling devices are locked, until they
are released by the action of the switches, the proper action of the switches being
proved by the release of the proper signalling device and so that if any failure of
the proof apparatus should occur the switches will not be prevented from operating,
which is important in shunting as failure of the proof apparatus might not be
noticed.
I will describe my invention with reference to the accompanying drawings.
Figure is an arrangement representing the application of my invention to
apparatus of the kind described in the Specification of my aforesaid application
for Letters Patent No. 3131 dated 20th February 1891, for working the proof
apparatus of one pair of switches or of two or more pairs of switches which are
operated simultaneously.
The switches may be operated by double acting cylinders but I prefer to work
them by single acting cylinders as shewn and described in the Specification of
Letters Patent herein before referred to.
Figure 2 represents a modification in the arrangement of the valves and details
of construction.
Referring to Figure 1 A is the main supply pipe for the motive fluid which for
the purpose of describing my invention 1 will assume to be water, it being under-
stood that other fluid pressure may be employed. The pipe A communicates by a
branch A with the interior of a valve box B which I term the main valve. This
valve box contains three ports or passages a band the ports a and b communi-
cating respectively by pipes a² band branches a³ ³ with the interiors of two
cylinders C and D and the port c communicating with a pipe or passage d leading
to the exhaust pipe E which may communicate with a tank from which the water
may be pumped into the accumulator for further use. The passage of the fluid
through the ports a b and c is governed by a valve e the rode of which is con-
nected to a bar e capable of sliding in guides e' when operated by the proper handle
or device.
When the valve e is in the position shewn in the drawing, water under pressure
enters the valve box B and passes through the port & into the pipe or passage b
and thence by the branch into the cylinder D whereby the piston D2 is by the
pressure of the water moved towards the opposite end of the cylinder forcing the
water contained in the said cylinder on the opposite side of the piston, through
the pipe or passage f leading to one of the single acting cylinders containing a
piston or plunger for moving the switch. The movement of the switch forces the
piston or plunger in the other or corresponding single acting switch cylinder to the
opposite end of the said cylinder thereby driving the water contained therein in
front of the piston through the pipe or passage g into the cylinder C. The water
entering the cylinder C at the back of the piston C² forces the said piston forward

page_text: .
to the opposite end of the cylinder and drives the water in front of the said piston
through the branch a³ pipe a² and ports a and c into the exhaust pipe or passage.
The rod D3 of the piston D is connected to one arm of a bell crank lever D*
the other arm of the said bell crank being connected by a pin or bolt to a proof
plate to which the rod C³ of the piston C is similarly connected by a bell
crank lever C and pin or bolt 2. The pins or bolts and e2 by which the bell
cranks D and C are connected to the proof plate F are free to slide in slots d³.c
in the said plate, the slots being of such a length and so situated that when the
piston D2 is moved in its cylinder by the fluid pressure to operate the switches,
the piston C2 in the cylinder C is moved by the fluid from the switch cylinder
entering the said cylinder C, through the passage, and gives motion through the
rod C³ and bell crank lever C to the proof plate F (if the proof apparatus be
in proper working order) towards the left hand thereby releasing such of the
proof bars G G3 G3 (and so on) in connection with the signalling devices as are
required to be released and assisting in the movement of the piston D2 in the
cylinder D. It will thus be seen that it is not possible to operate the signals
without first placing the corresponding switches in the correct positions. To
return the switches to their former position the valve e is moved so as to establish
communication between the ports and c in the valve box B and open the
port a to the pressure of the fluid entering the box B, through the main supply
pipe A.
The fluid then passes through the port a into the pipe or passage a² and
branch thence into the cylinder C. The piston C is thus driven back towards
the end of the cylinder from which it had been moved, the fluid in front thereof
being forced through the pipe or passage into one of the switch cylinders so as
to return the switches to their former positions the fluid in the other of the switch
cylinders being forced through the pipe or passage f into the cylinder D. The
piston D is thus moved in the cylinder D to its former position and through its
rod D and bell crank. lever D draws the proof plate towards the right hand
thereby again locking such of the proof bars G G2 G3 in connection with the
signalling devices which had been released, and returned to their former position,
the proof plate assisting to move the piston D' to its former position in the
cylinder D. The cylinders C and D are each provided with a passage h and i,
comm: nicating respectively with the pipes or passages and a. The passages h
and are fitted with valves 2 connected to levers which normally maintain
the valves closed these levers being suitably weighted to prevent the valves opening
until the pressure on the cylinders rises above that required to move the proof
apparatus and should be such that by the time or just before the switches reach
the full extent of their motion the pressure of the fluid will open the valve and
admit the full pressure of the fluid to act on the piston of the switch cylinder and
keep the switches in the position to which they had been moved. When the
switches are operated by the pressure of the fluid entering one of the single
acting switch cylinders as described the fluid in the other or corresponding
switch cylinder is forced into the cylinder C or D, as the case may be, to
effect the movement of the proof plate F as hereinbefore described. If the
proof apparatus acts properly the valve in connection with this cylinder will remain
closed but if the proof plate E should foul any of the proof bars G G G or should
stick from any other cause the piston will be prevented from moving and con-
sequently the pressure of the fluid will open the valve and allow the fluid to escape
into the exhaust passage E. For example suppose a pressure of 60 lbs. per square
inch in the main pipe A is sufficient to move the switches and perform all the other
operations required and suppose a pressure below 20 lbs. per square inch to be
sufficient to move the proof apparatus then the valves and might be weighted
so as to open with a pressure of not less than 40 lbs. per square inch. If the
valve e is in the position shown in the drawing the fluid will be admitted to the
cylinder D by the port bas herein before described and the pressure on the piston D³
and also behind the valve will be uniform (60 lbs.) and the switches will be
I moved to their full extent the pressure on the other side of the piston while the

page_text: switches are moving being less than 60 lbs. per square inch. While this is taking
place it is immaterial whether the valve 2 is open or closed because the area on the
upper side of the piston D' being much greater than the area of the lower side the
piston will have a strong tendency to be forced downwards and will in fact be com-
pelled to move downwards by the action of the proof plate F. Therefore even if
the valve be open at this stage no fluid will pass through it. However small
the pressure on the valve K may have been while the switches were moving it is
certain that by the time or just before the switches reach the full extent of their
motion the pressure on the valve 2 will rise above 40 lbs. and consequently open
the said valve and establish through the passage a communication between the
pipe a and the passage fleading to the switch cylinder so that the switches will be
acted upon by the full pressure of 60 lbs. and held in the position to which they
had been moved. Now suppose that a pressure of 20 lbs. per square inch on the
piston C is sufficient to move the proof plate F when the proof apparatus is in
proper working order then the fluid forced from the other switch cylinder and
entering the cylinder C will readily effect the movement of the proof plate as
hereinbefore described and release the required proof bars but should the proof
plate foul any of the proof bars G G or G³ or stick from any other cause, the
piston C will be prevented from moving and the pressure of the fluid in the
cylinder will rise to or above 40 lbs. and open the valve and allow the fluid to
pass through the passage i into the pipe and thence through the ports a and c
into the exhaust pipe E. It will thus be seen that any failure in the proper
working of the proof apparatus cannot prevent the proper action of the switches.
I have described and shown in the drawing the proof plate as being moved by the
backward stroke of the pistons C and D but it is obvious that the arrangement
may be modified so as to move the proof plate by the forward stroke of the said
pistons the essential feature of the invention being that the proof plate cannot be
moved otherwise than by the fluid set in motion by the movement of the switches.
Figure 2 is a view similar to Figure 1 showing a modification in the arrangement
illustrated by Fig. 1. In this arrangement three valve boxes B B2 B3 are provided
the box B being in direct connection with the main supply pipe A and the
boxes B2 B3 being connected respectively by the pipes and with the two single
acting switch cylinders. The valve box B contains two ports a and b communi-
cating respectively with the valve boxes B2 B3. The valve box 132 contains in
addition to the port a two other ports and the port e leading to the exhaust pipe
or passage E and the port communicating by a pipe a with a passage leading
into one end of a cylinder C. The valve box B3 also contains in addition to the
port two other ports e¹³, the port c¹ communicating with the exhaust pipe E
and the port communicating by the pipe or passage with a passage i leading
to the interior of the cylinder C at the opposite end to that which is in connection
with the valve box B². The passage for the motive fluid through the ports in the
valve boxes B B2 B3 is governed by valves e el and e" carried on a bar e² operated
by a switch lever as in the first described arrangement. The passages and i
leading into the opposite ends of the cylinder Care provided with weighted
valves corresponding to those described and shewn in Figure 1. When the
valves e e e are in the position shown in the drawing the motive fluid entering the
valve box B from the main pipe A passes through the port a into the valve box B³
and thence by the pipe or passage to one of the switch cylinders to move the
switches. The fluid from the other one of the switch cylinders is forced by the move-
ment of the switclies through the pipe into the valve box B³ whence it passes
through the port into the pipe or passage 2 by which it is conducted into the right
hand end of the cylinder C. The piston C in this cylinder is thus caused to travel
towards the left hand end of the cylinder and as this piston is connected to the
proof plate the said plate will be moved so as to release such of the proof bars as
are required to be released as herein before described with reference to Figure 1.
The fluid contained in the cylinder is forced by the piston C through the passage h
into the pipe or passage a² whence it passes through the ports k and c in the valve
"

page_text: box B2 into the exhaust pipe E. By moving the valves e el ell so as to open the
ports and the pressure of the fluid entering the valve box B will operate in the
reverse direction to that last described and will return the switches and the proof
plate to their former positions as hereinbefore described with reference to Figure 1.
The valves are suitably weighted to remain closed so long as the proof
apparatus works properly but so that should the proof plate foul the proof bars or
stick from any cause the pressure in the cylinder will rise sufficiently to open the
valves and allow the fluid to escape. H is a stop cock in the fluid supply pipe A
for the purpose of cutting off the supply of fluid to the valve box 13 when required.
Any leakage of the fluid past any valve intended to be closed would flow into the
exhaust pipes E or E and could not cause accidents, nor cause the proof apparatus
to indicate motions of the switches which had not taken place. The valves 2, 12,
operate in the following manner. Suppose the piston C to stick while moving
from right to left. The fluid would first force open the valve and then the
valve and then pass through the pipe a² and through the ports kc to the
exhaust E.
If the valves were each connected direct to an exhaust pipe or even with
the open air instead of being connected together the fluid would only have to open
one valve in order to escape.
My invention is equally applicable to facing switches and falling switches and
an important advantage obtained by my invention is that any failure of the proper
action of the proof apparatus cannot prevent the proper action of the switches
and this is very important in shunting or other operations in which the failure
of the proper action of the proof apparatus might be overlooked or unobserved.
Having new described and particularly ascertained the nature of my invention
I wish it to be understood that I do not restrict myself to the construction and
arrangement of the parts herein before described and illustrated but what I
claim is
1st. In or connected with apparatus for operating switches and signals on
railways in which the switches are operated by fluid pressure, means whereby
the proper signalling devices are locked and released by the movement of the
switches and the proper action of the switches proved by the release of the
proper signalling devices, substantially as herein before described, and whereby if
any failure in the action of the proof apparatus should occur the switches will
not be prevented from operating.
2nd. In connection with apparatus for operating switches and signals on railways
in which the switches are operated by fluid pressure, means whereby the fluid after
operating to move the switches is caused to operate apparatus to prove the
movement of the switches, and if the proof apparatus is in proper working order
release signalling devices, or if the proof apparatus sticks so as not to be moveable
by the fluid pressure a valve will open and allow the fluid to pass into an escape
pipe substantially as hereinbefore described.
3rd. The combination and arrangement of apparatus for use with switches and
signalling devices on railways substantially as and for the purpose herein before
described and illustrated by Figure 1 of the accompanying drawings.
4th. The combination and arrangement of apparatus for use with switches and
signalling devices on railways substantially as and for the purpose hereinbefore
described and illustrated by Figure 2 of the accompanying drawings.
Dated this 7th day of March 1892.
J. H. JOHNSON & Co.,
Agents.