mprovements in Mechanism for Actuating "Points" or "Switches" and Signals on Railways.
Year: 1890

page_text: Date of Application, 3rd May, 1890
Complete Specification Left, 2nd Feb., 1891-Accepted, 14th Mar., 1891
PROVISIONAL SPECIFICATION.
mprovements in Mechanism for Actuating "Points" or "Switches"
and Signals on Railways.
I, CUTHBERT ELLISON CARR, of Hedgeley, Alnwick, in the County of
Northumberland, Engineer, do hereby declare the nature of said invention to be
as follows:-
:-
This invention relates to further improvements in the mechanism for effecting
all the necessary operations upon the points or switches and upon the signals, in
their proper sequence, as fully set forth and described, with the objects aimed at
and advantages secured, in my prior Specification No. 15077 of September 24 1889,
such mechanism being alternative to some of the various arrangements (especially
the rocking bar system), therein described and illustrated, for opening and closing
cocks or valves by which fluid or air under pressure is admitted to, or released
from, cylinders fitted with pistons or rams connected with the switches and with
the signals.
According to my present invention in one system of carrying it into practical
application, taking the same junction described in my Specification No. 15077
of 1889 as an illustration, there are 16 handles in the cabin to work the 11 pairs of
switches and the 18 signals. Each handle is connected to a bar (preferably vertical)
working in guides and actuating, by cross bars, 3 series of horizontal sliding plates,
working in guides, in which are slots of suitable shapes to cause the vertical move-
ments of the cross bars, actuated by the various handles, to give them a reciprocating
horizontal movement. Six of the sliding plates operate the 10 switches which are
double ended, and work in 5 pairs together, and one switch is single ended an.l
these six plates are connected to valves which control the admission to or release
from the ends of the switch cylinders of the fluid under pressure, the valves being
opened and closed, in proper sequence, by the horizontal movements of the sliding
plates imparted to them by the different handles. For the purpose of interlocking
the handles there are 5 sliding plates with shaped slots in which cross bars operate
so as to give horizontal movements to the plates which will cause such handles as
require to be locked to be prevented from being moved improperly. For working
3 of the distant signals 3 slotted plates are required the movements of which by the
cross bars open and close valves which control the admission to and release from
these signal cylinders of the fluid, the other distant signal, which requires only to
be worked fron one handle, being worked direct by a slot in the vertical bar
connected to valves in the pipes which communicate with that signal cylinder.
The stopping signals are also worked direct from slots in the vertical bars con-
nected to valves in the pipes which communicate with the signal cylinders. An
additional precaution is provided against any signal being lowered, until the switches
it protects are fully over and secured, by a series of sliding plates (in this instance
6 in number) each of which is connected by rods with the tongue of a sw.tch or
with the locking wedge, so that, until any switch is fully over and secured, the
handle which works the signal protecting that switch is locked by the crossbar
being imprisoned in the slot in the sliding plate and the signal cannot be lowered
until the switch, by having moved fully over, has moved the sliding plate
sufficiently to release the pin in the notch and so allow the handle to be operated.
If the normal position of the switches is right for the lowering of the signal the
rods from the switches are so placed, with reference to the crossbar, that the
vertical bar is free to move but will be locked by any movement of the switches
from their normal position.

page_text: In an alternative form of my invention which for simplicity of mechanism
facility in manipulation saving of space and of wear and tear I consider superior to
the other, I employ 2 sets of handles, one set for actuating the signals, which I will
call the A serios, and another set of handles which I will call the B
actuate the switches, wedges and locking bars.
series
to
In the A series there will be as many handles as there are primary signals to be
worked, and each handle will bear a corresponding number to the primary signal
which it works. Each of these handles will give motion to a sliding rod which, by
means of curved slots, levers, rocking bars or other suitable mechanism will opi
and close the valves on th
pressure and release pipes leading to the signal
cylinders in such a manner that, when a handle is in its normal position the corre
sponding signal will be at danger and, when the han ile is pulled over, the signal
will be lowered. When a distant signal is worked in connection with any stopping
signal, the first portion of the motion of the handle will lower the stopping signal,
and the second portion of the motion will lower the distant signal.
In the Bries there will, in this instance, bath same number of handles as in
the A series and bearing corresponding number. Each of the handles will art
on one or more pairs of switches which must be set before the corresponding sign d
can be lowerel, or, in the eu in where no witches require to be moved from the'r
normal, the B handle will simply work a locking bar to prevent a contra-
dictory in being lowered ur a wrong switch being moved.
ans
..
Each of the handles in the B seri will impart a reciprocating motion to one of
1 series of Eding plates in which are for evriel or com shaped slots. The en
plates cross as rigla angles avezns of sliding bar, which, by a reciprocative mov
mont, can open and cloe the valves on the pressure an 1 release pipe len Eng to the
end of the weh eylinders. In the later sliding bar are proferting pins which
engage in the earl slot in the filing plates moved by the handle, so that when
handle of the B series is pulled over it will move the corresponding sliding
plate, which will. by mean of the curved shots and projecting pin, move suels of
the sliding bus may be required to set the witches, corre-poiling to the signal
to b· lowered, and at the same time to fork such of the other handle as could
contradictory signals or move opposing switches. This locking arrangement in
effected by forming at the end of each curved slot in the sliding plates a lateral
slut into which the projecting pin of the sliding bar will pass as it is moved forward
by the petion of the curved slot of some of the other sliding plates, and until the
pin is removed from the lateral slot, by the reverse movement of the B lever which
moved it into that position, none of the other hamil. in the series so locked can
be novel.
#*
Each handle in the B series is also made to lock a corresponding hamlle in
the A series by means of a connection from the sliding plate engaging in a slot in
the sliding bar, moved by the corresponding signal handle in the A series and until
this lock is removed, by first drawing over the handle in the B series, the corre-
spoiling handle in the A series cannot be moved to lower the signal. Each handle
in the A series is further locked by a rod passing from the tongue or wedge of the
switch, as described in my previous system, so that no signal can be lowered until
the switches which it controls are fully over and wedged home.
Where it is not desired that the slotted har from a 13 handle should move a
sliding plate, so as to actuate a given set of switch valves, but that nevertheless
the movement of the latter plate shoull lock the former, the slot in the former is
made straight, with a lateral notch at one end, so that the movement of the sliding
plate does not move the rod which artantes the switch valves but the pin in it locks
the slotted bur by entering the lateral notch in the slot.
The general principles upon which the required operations are arranged in both
systems are as follows:-
If I wish to lower a given signal 1 must first perform certain preliminary
operations by the movement of a handle in the B series bearing the same number
as the signal to be lowered,

page_text: The handle in the A series which actually lowers the signal cannot be moved
till this is done and when a handle in the A series has been moved from its normal
position it must be replaced in its normal position before the corresponding handle
in the B series can be replaced in its normal position.
The preliminary operations are:-
1st. The moving of all switches that have to be moved to allow the train to pass
in the required direction.
2nd. The moving of all switches that have to he moved to prevent the possibility
of other trains coming onto the line.
3rd. The locking in their normal positions of all switches, that ought to be kept
in their normal positions, to allow of the safe passage of the trains.
4th. The locking in their normal positions of all switches, that should be kept
in their normal positions, to prevent the possibility of other trains getting on
the line.
5th. The locking of all signals the lowering of which could give conflicting
instructions to those in charge of the train.
6th. The locking of all signals the lowering of which could permit other trains
to come upon the line and cause an accident.
Dated this 3rd day of May 1890.
T. J. DANSON.
Per L. W.
Improvements in Mechanism for Actuating "Points" or "Switches"
and Signals on Railways.
I, CUTHBERT ELLISON CARR, of Hedgeley, Alnwick, in the county of
Northumberland, Engineer, do hereby declare the nature of said invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement :-
This invention relates to further improvements in the mechanism for effecting all
the necessary operations upon the points or switches and upon the signals in their
proper sequence as fully set forth and described with the objects aimed at and
advantages secured in my prior Specification No. 15,077 of September 24, 1889, to
which I beg leave to refer such mechanism being alternative to some of the various
arrangements (especially the "rocking-bar system) therein described and
illustrated for opening and closing cocks or valves by which fluid or air under
pressure is admitted to, or released from, cylinders fitted with pistons or rams
connected with the switches and with the signals.
According to my present invention in one system of carrying it into practical
application, taking the same junction described in my Specification No. 15,077
of 1889 as an illustration, there are 16 handles in the cabin to work the 11 pairs of
switches and the 18 signals. Each handle is connected to a bar (preferably vertical)
working in guides and actuating, by crossbars 3 series of horizontal sliding plates,
working in guides, in which are slots of suitable shapes to cause the vertical
movements of the crossbars, actuated by the various handles, to give them a
reciprocating horizontal movement. Six of the sliding plates operate the 10 switches
which are double ended and work in 5 pairs together, and one pair which is single
ended and these six plates are connected to valves which control the admission to or
release from the switch cylinders of the fluid under pressure, the valves being
opened and closed in proper sequence by the horizontal movements of the sliding
plates imparted to them by different handles. For the purpose of interlocking the
handles there are 5 sliding plates with cam shaped slots in which crossbars operate
so as to give horizontal movement to the plates which will lock such handles as
require to be locked. For working 3 of the distant signals 3 slotted plates are

page_text: required the movements of which by the crossbars open and close valves which
control the admission to and release it from these signal cylinders of the fluid, the
other distant signal, which requires only to be worked from one haulle, being
worked direct by a slot in the vertical bar connected to valves in the pipes which
communicate with that signal cylinder. The stopping signals are also worked
direct from slots in the vertical bars connected to valves in the pipes which
communicate with the signal cylinders. An additional security is provided against
nny signal being lowered, when any facing switches which it protects are not
occupying exactly the right position, by a series of sliding plates (in this instance
in number) each of which is connected by rods with the tongue of a switch or
with the locking wedge so that, until any switch is fully over and secured, the handle
which works the signal protecting that switch is forked by the crossbar being
impri-ioned in the slot in the sliding plate and the signal cannot be lowered until
the witch, by having moved fully over, has moved the sliding plate sufliciently to
rele: the pin in the notch and so allow the handle to be operated.
If the normal position of the facing switches is right for the lowering of the
signal the rods from such facing switches are so placed, with reference to the
eros bars, that the vertical bar is free to move but will be locked by any movemeni
of the switches from their normal position.
In an alternative form of my invention employ 2 sets of handles, one set for
netrating the signals, which I will call the A Series, ant another set of handle.
which will call the B series to actuate the switches, welges nud locking bars.
In the A series there will be as many handles as there are "primary" signals to
be worked that is to say signals the lowering of which does not depend upon the
previons lowering of any other signal and each handle will bear a corresponding
number to the "primary" signal which it works. Each of these handles will give
motion to a sliding rod which, by means of curved slots, levers or rocking bars or
other suitable mechanism will open and close the valves on the pressure and release
pipes leading to the signal cylinders in such a manner that, when a handle is in its
normal position the corresponding signal will be at danger and when the handle is
pulled over, the signal will be lowered. When a distant signal is worked in
connection with any stopping signal, the first portion of the motion of the handle
will lower the stopping signal, and the scowl portion of the motion will lower the
distant signal.
fn the B series there will be handles for operating the switches to be operated
and for effecting the necessary lurking of switches and ignals; and if any of these
operations have to be effected before the lowering of a primary signal one of the
hamlles in the B series is alloted to that primary signal to effect the required
preliminary operations. The remaining handle in the B series perform similar
operations but have no corresponding handles in the A series.
Each of the handles in the B series will impart motion to one of a series of sliding
plates in which are formed curved or cam shaped slots. These plates cruss at right
angles a series of sliding bars which, by a reciprocating movement can open and
close the valves on the pressure and release pipes leading to the switch cylinders.
In these latter sliding bars are projecting pins which engage in the curved slots in
the sliding plates moved by the handles, so that when any handle of the B series is
pulled over it will move the corresponding sliding plate, which will, by means of
the curved slots, and projecting pins move such of the sliding bars as may be
required to set the switches corresponding to the signal to he lowered, and at the
same time to lock such of the other handles as could give contradictory signals or
more switches which ought to be kept in their normal positions. This locking
arrangement is effected by forming at the end of each curved slot in the sliding
plates a lateral slot into which the projecting pin of the sliding bar will pass as it
is moved forward by the action of the curved slot of some of the other sliding plates,
and until the pin is removed from the lateral slot, by the reverse movement of the
B lever which moved it into that position, none of the other handles in the B series
so locked can be moved.

page_text: Each handle in the B series which is alloted to a primary signal is also made to
lock a corresponding handle of that primary signal in the A series by means of a
onnection from the sliding plate engaging in a slot in the sliding bar, moved by
the corresponding signal handle in the A. series and until this lock is removed by
irst drawing over the handle in the B series the corresponding handle in the A series
cannot be moved to lower the signal. Each handle in the A series is further locked
by a rod passing from the tongue or wedge of any facing switch protected by it as
described in my previous system, so that no signal can be lowered unless the facing
switches which it protects are occupying exactly the right position.
Where it is not desired that the slotted bar from a B handle should move a sliding
plate, so as to actuate a given set of switch valves, but that nevertheless the
movement of the latter plate, if moved by another handle, should lock the slotted
bar the slot in the latter is inade straight, with a lateral notch at one end, so that
the movement of the slotted bar does not move the sliding plate which actuates the
witch valves but when the latter is moved by any other handle the pin in it locks
the slotted bar by entering the lateral notch in the slot.
The general principles upon which the required operations are arranged in both
ystems are as follows:-
If I wish to lower a given signal I must first perform certain preliminary
operations by the movement of a handle in the B series bearing the same number as
the signal to be lowered. The handle in the A series which actually lowers the signal
cannot be moved till this is done; and when a handle in the A series has been
moved from its normal position it must be replaced in its normal position before the
corresponding handle in the B series can be replaced in its normal position. The
preliminary operations are ri:—
Ist. The moving of all switches that have to be moved to allow the train to pass
in the required direction.
2nd. The moving of all switches that have to be moved to prevent the possibility
of other trains coming onto the line.
3rd. The locking in their normal positions of all switches, that ought to be kept
in their normal positions, to allow of the safe passage of the train.
4th. The locking in their normal positions of all switches, that should be kept
in their normal positions, to prevent the possibility of other trains getting on
the line.
5th. The locking of all signals the lowering of which could give conflicting
instructions to those in charge of the trains.
6th. The locking of all signals the lowering of which could permit other trains to
come upon the line and cause an accident.
It will be understood that all the required operations upon the switches and
signals, as fully described in the Specification of my Patent No. 15,077 of 1889 are
performed according to my present invention without the intervention of loop pipes
which form part of my aforesaid patent.
DESCRIPTION OF DRAWINGS.

page_text: connections by moving a separate set of handles into a series of consecutive positions
and Sheets 7 and 8 shew details of the mechanism of the slotted bars and double
rol by which the switches are moved and the signals are locked from the facing
switchies.
The junction taken as an illustration is an actual case on an English railway
shown on Sheets 4 and of the drawings accompanying my Specification No. 15077
of 1889 and described therein in which there are 11 switches to be moved riz. :—
No. 1-2, 3-4, 6-7, 8-10, and 9-11 all of which are double ended and are
nctuated together and No. 5 which is single ended; and there are 18 signals
marked to 18 on Sheets 4 and 4 of said drawings protecting these switches. To
elect all the required movements of these switches and signals by one series of
handles in their proper sequence 16 handles are required as shown on Fig. 2 of
Sheet 1 and on Fig. 1 of same sheet is shewn an end elevation of the mechanism
connected with one of these handles,
There are 6 sets of pressure and escape valves marked Pand E respectively for
the switch cylinders which are opened and clo-ed by the lateral movement of
6liding plates marked SPL SPA SP SP SP SP on Fig. 1 Sheet 1. The
teral reciprocating movement is given to these plates by "eross burs" (1 whieh
pass through slots in the plates.” These crossbars are raised and lowered by the
ovement of the hall. Each of the 16 hamiles is compled direct to a vertical
bar VB working in guides (i, nil the ends of the crossbars CB are connected to
side rods SR. The side rods SR at their upper ends are connected to cross-
heads on the vertical Jars VB so that when the vertical bar is raised or
lowered the whole frame moves with it.
At the lower end of each vertical bar VB is a curved slot S which actuates the
valves Pand E for the stopping signal of each set of switches. Since handle No. 1
is not required to work any switches there is no crosshend nor are any crossbars
attached to it.
Emmylitely below the liding plates for switches are 5 other sliding plates
which do not actuate any valves but merely interlock the handles.
Below these interlocking plates are 3 other sliding plates which actuate the
valves for the distant signals (except distant signal No. 15 which always works in
conjunction with stopping signal 14 and therefore is worked direct froin the lower
end of vertical bar No. 11 as is shewn on Fig. 2 Sheet 1).
The 6 plates in the bottom row Figs. 1 and 2 are moved by the tongues of the
facing switches and lock the handles so that no handle can be pulled over far enough
to lower a signal unless the facing switches worked by it are occupying exactly the
right positions.
In Figs. 1 and 2 Sheet 1 all the handles are shewn in their "normal" position
when one of the pressure valves P of the switch cylinders will be open and the other
closed the corresponding escape valve E of same being respectively closed and
open while the pressure valve P of signal cylinders are closed and escape
valves are open. The movement of any handle from 0 to 1 Fig. 1 Sheet 1
will cause its sliding plate to be moved to the left hand and reverse the positions of
the four valves P, E, of the switch cylinders, and at the same time move one of the
Jocking sliding plates so as to lock all handles which could give a contradictory
signal.
As soon as the facing switch tongues are fully over the lock plate from the facing
switch will be moved far enough over to the left to allow the handle to be moved
from 1 to 2. When the pressure pipe of the stopping signal cylinder will be
oponed and the escape pipe closed by means of the slot S in the lower portion
of the vertical bar VB. On the further movement of the handle from 2 to 3
one of the sliding plates for the distant signals will be moved to the left and
close the escape valve E and open the pressure valve P of the corresponding
distant signal cylinder. In the case of distant signal No. 15 worked by handle No. 11,
this is done direct from the vertical har by a slot formed therein (see Figs. 1 and 2
Sheet 1) without a sliding plate. The slot in the vertical bar and the weight on

page_text: the lever for moving the distant signal valves, are used in order to enable a
distant signal to be worked in connection with any one of two or more stopping
signals.
On Sheets 2, 3 and 4 the sliding plates are shewn for clearness separately with
their slots. Fig. 1 shews the 6 plates SPI to SP for the switch cylinder valves.
Fig. 2 shews the 5 sliding plates A. B. C. D and E for interlocking the handles.
Fig. 3 shews the 3 sliding plates for the distant signal cylinder valves. Fig. 4 shews
the 6 sliding plates LB, LB, LB³, LB, LB & LB, moved by the switches. All
these series of plates may move upon rollers R in vertical guide plates shewn on
Fig. 2 Sheet 1. Fig. 5 is a diagram of the position of the handle H, indicated by
a thick line. On this sheet the handle is in its "normal" position at and the
position of the crossbars in the slots is indicated thus
The movement of handle No. 5 is taken as an example on this aud the following
sheets. The vertical bar attached to handle No. 5 is shewn on all the figs. Sheets 2. 3
and 4 by a thick line.
The reference numbers of switches and signals refer to Sheets 4 and 4 of the
drawings with Specification No. 15,077 of 1889, shewing the junction taken as an
illustration.
On moving handle II from 0 to 1 (see Fig. 5 Sheet 2) the sliding plates for
switch cylinders 1-2, 5, and 6-7 will be moved over to the left by the upward
movement of the vertical bar VB and of the crossbars CB acting upon the inclina
portions of the slots, and these switches will be moved over, and at the same time
the interlocking plates A, B, C and E will be moved to the left and lock the handles
Nos. 2. 3. 4. 6. 7. 8. 9. 10. 12. 13. 14. 15. 16. The sliding plates are all now in the
positions shewn on Sheet 3.
As soon as the switches 1-2, 5, 6-7 are fully over the sliding plates LB', LI',
LB, LB LB aml LB" Fig. 4 Sheet 2 moved by the tongues of the switches will
have moved sufficiently far to the left hand to remove the lock from handle 5 by
allowing the crossbar to enter the narrow portion of the slot and until this is done
handle No. 5 could not be pulled over any further (see Fig. 4 Sheet 3).
The next movement of handle No. 5 from 1 to 2 will not affect any of the sliding
plates the crossbars merely moving up the straight portion of the slots but the val e
for stopping signal cylinder No. 5 will be moved by the curved slot at the lower end
of the vertical bar and stopping signal 5 will be lowered.
On moving handle No. 5 from 2 to 3 on the diagram Fig. 5 Sheet 4, the sliding
plate for distant signal cylinder No. 4 will be moved over to the left by the cross-
bar entering the inclined portion of the slot at the top (see Fig. 3 Sheet 4) and
distant signal No. 4 will be lowered.
This completes the series of operations effected by handle No. 5 upon the switch
and signals attached to it and the other handles perform the same operations upon
their respective switches and signals in similar sequence.
If it is necessary to raise a distant signal after being lowered, without altering the
switches as then set, the backward movement of the handle from 3 to 2 (see
diagrams) will effect this and a stopping signal can be raised by a further movement
from 2 to 1 without moving the switches and these signals will be again lowered by
moving the handle from 1 to 2 and from 2 to 3.
I now proceed to describe the alternative method of working my invention .n
which separate sets of handles are used for operating the switches and signals.
Referring to Sheet 5, Figs. 1 and 2, the series of 14 handles which work the
signals are marked H from 1 to 14 and the series of 15 handles which work the
switches are marked HSW from 2 to 16.
Each signal handle is attached to a vertical bar VB working in guides G, whith,
by means of short levers L, open and close the pressure and escape valves E, pip s
to and from which lead from the main pressure pipes MI, and to the main ese e
pipes ME and to the stopping signal cylinders. These valves are so constructed
that a movement of the handle H³ from 0 to 1 on sector lowers the stopping signal
and a backward movement allows it to rise to danger. In order to lock the signal

page_text: hamilles and prevent a signal being lowered unless all facing switches covered by it
are occupying exactly the right position each of the vertical bars VB of such
signals as cover firing points are connected to horizontal sliding locking bars LB
having projections upon them which pass through slots in sliding plates LP
(shewn in detail on Figs. 1, 2 and 3 Sheet 8) which are connected with the facing
switch tongue-.
Referring now to Sheet 6 Figs. 3 and 4, each of the series of switch handle w
is connected direct to a horizontal sliding bar 11B working in guides (1. In these
horizontal bars are curved slots S shewn in detail by Figs. 5 nid 6 in which engage
pins X in the 8 double rods DRABC which cross at right angles and work the
valves of the switch cylinders anal other double real markel X, Y & Z which
lock the bars B but do not operate any pressure and escape valves. One set of
the pressure and escape valves of the switch cylinders and the mechanisin commecte 1
with them are shewn on Fig. 3 the valves being marked Paul E, P³and 1' from
which pipes lead to the opposite ends of the switch cylinders_and_these 4 sets of
valves are operated by levers L and L' from the 6 double rods DR to DR. In
all cases where it is meressary to move a pair of switches before a signal can le
lowered a slot in the projecting end of the horizontal bar HB ones a pin in the
vertical har VB of the signal handle (see Fig. 1. Sheet 3) in such a manner that.
until the witch handle of the series is fully over from 0 to 1, the correspondling
signal hand is locked by the pin being in the position shewn on Fig. 1 Sheet 5.
The operation of these horizontal bars and their attached mechanism will be fully
de-cribed with reference to Figs. 1 and 2 Sheet 7 where they are -hewn more
clearly.
Referring to these figures there are 15 horizontal bar- HB, Nos. 2 to 16, and
crossing these at right angles are ti rols marked A, B, C, D, E & F' which operat»
the valves of the cylinders which actuate the switches A, B, C, D) E & F shewn on
plan of junction and 3 other rods marked, X, Y & Z, which do not work any valves
but interlock the bars HB in such a manner that two incompatible switches or
signals cannot be moved together. Taking Nu. handle as an example: on Fig. I
all the lars are in their normal position the hamlles being in the position shewn at 01
on sector diagram below.
Od Fig. 2 No. 5 handle has been pulled over into position 0 to 1 on diagram and
has moved the double rods C, D & F to the right, by the operation of the slots in
the bar HB of No. 4 handle upon the pins in the said rods and at the same time
has interlocked all the other handles which could move incompatible switches. The
switches (, ) & F have now been changed and No. 5 handle of II series has been
unlocked so as to allow the stopping signal No. 5 to be lowered. The action of the
other handles is similar in changing their respective switches interlocking the other
handles and unlocking the corresponding signals,
On Figs. 1, 2 and 3 Sheet 8 is shewn the mechanism by which the signal handles
are locked by the facing switch tongues as previously referred to,
From the tongues of the facing switches connections are made by rods with the
6 sliding locking plates LP in which are angle shaped slots through which the
locking bars L from the signal handles pass as shown by Fig. 1.
On these locking bars are projections which can only pass through slots in the
plates 1, when the switches have been moved fully over, and so eimble the signal
to be lowered.
Figs. 2 and 3 show this locking mechanism in two different positions, still taking
No. 5 handle as an example. On Fig. 2 the switch D is in its normal position and
No. 4 handle is locked by the projections on the rod LB being unable to pass
through the slots until the switch D is moved fully over when the position is that
shewn on Fig. 3 the signal handle No. 4 having been now released and pulled over
as shewn, the projections on the rod LB have passed through the vertical portions
of the slots in the locking plates LP which have been moved by the changing of
the switch.
Although I have described and illustrated the sliding plates as actuating recipro-

page_text: ing slide valves I may as an alternative arrangement cause them to actuate
olving valves or cocks.
for cases in which two or more pairs of switches have always to be moved
ether one set of valves will be sufficient for all the cylinders the pipes being
ided into branches after they leave the valves so as to lead to each end of the
inders at the switches.
t inny sometimes happen that it is desirable that some or all of the switches to
moved for a given junction shall move in a particular order.
This result may conveniently be brought about as follows:-The piston rod of
cylinder of the switches that are to move first may be made to control a supple-
ntary valve or valves upon either the branch pressure or escape pipe, or upon
h the branch pressure and escape pipes, through which the fluid has to pass in
ving the switches the motion of which is to be delayed. In this way the switches
ny group may be made to move in any order that is desired in one or both
ections. The control of the operation of one or more pairs of switches by that of
or more other pairs may be effected in several ways but the above method is
ple and perfectly efficient.
Having now particularly described and ascertained the nature of my said inven-
, and in what manner the same is to be performed. I declare that what I
im is:-
First. For the purpose of performing the following operations upon switches and
nals in their proper sequence riz.;
1st. Remove all pressure from the switches, as then set raise the locking or
safety bar; withdraw the wedges and move the switches over; lower the
locking bar and replace the wedges.
2nd. Lower a stopping or other primary signal.
3rd. Lower a distant or other secondary signal (if required) and, by backward
movements of different handles from certain positions, to allow a signal
previously lowered to rise to danger, when necessary, and again to lower it
without interference with other signals or with the switches, as then set; by
fluid air or gas under direct pressure or the pressure of the atmosphere
admitted to and released from eylinders fitted with pistons or rams the
application of apparatus consisting of one set of hand levers connected to bars
working in guides and currying crossbars which pass through slots in plates,
of such shapes that the travel of the crossbars gives to the plates recipro-
eating sliding motions and, by suitable connections, causes them to open or
close valves or cocks by which pressure is admitted to or released from
cylinders which actuate certain switches and signals; or slots formed in the
bars connected to the hand levers which open and close valves or corks by
which pressure is admitted to or released from cylinders which actuate
certain signals direct, without the intervention of slotted plates and crossbars,
by the movement of certain handles.
Second. For the purpose of performing the above operations the apparatus
sisting of two sets of hand levers one set actuating the switches and the other set
uating the signals connected to bars working in guides which bars op rate slotted
ling plates so as to cause reciprocating movements in bars crossing said słotred
ling plates transversely at right angles and by connections from these bars to
n or close valves or cocks by which pressure is admitted to or red from
inders which actuate certain switches and signals or slots formed in the bars
merted to the hand levers which open an I close valves or cocks by which pressure
admitted to or released from cylinders which actuate certain als direct,
hout the intervention of slotted plates and transverse bars by the movement of
tain handles.
Third. In conjunction with such mechanism the use of slotted sliding plates which
the operation of crossbars or of pins in transverse bars moved by the handles
se the movement of one handle to interlock all the others and prevent any of
I}

page_text: them being moved whilst that one handle is operating substantially as described and
shawn.
Fourth. In conjunction with such mechanism the use of slotted sliding plates
connected with the tongues of the switches in such a manner that, until the tongues
are fully over and secured, the crossbars are so locked in the slots as to prevent any
of the handles being moved so as to lower a signal.
Fifth. The use of supplementary valves by means of which several pairs of
switches may be made to move in any required sequence.
T. J. DANSON, F.I.P.A.,
2, St. Nicholas' Buildings, Newcastle-upon-Tyne, Agent for Applicant.