Improvements in or applicable to Railway Signalling Appliances Worked on the Block System.
Year: 1893

page_text: Date of Application, 17th July, 1893-Accepted, 2nd Sept., 1893
COMPLETE SPECIFICATION.
Improvements in or applicable to Railway Signalling Appliances
Worked on the Block System.
I HORATIO OGDEN of 5 Collin Street, Warrington in the County of Lancaster,
Railway Signalman, 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 said invention relates to improvements in or applicable to railway signalling
appliances worked on the block system.
For facility of explanation I will describe my said invention as applied only to
two connected stations on a line of railway hereinafter referred to as the advance
and the rear stations each having a single signalling lever only, it being however
understood that any number of signal levers controlling different lines may be
collected together.
In practice except at terminal stations rear and advance
signal stations are merely comparative terms at any given point on the line since
the advance station at one point is the rear station of the next and so all along
the line.
In the block system of signalling when the man in the rear signal station desires
to allow a train to pass his station on to the section of line between him and the
advance station he transmits by telegraph what is known as the be ready" signal
to the advance station. If the road is clear the advance station telegraphs its
acceptance of this signal by telegraphing "line clear" whereupon the rear station
allows the train to pass and telegraphs to the advance station "train on line," the
signal of the rear station being then set at danger after the train has passed. The
advance station then takes charge of the train until it has passed out of the section
of the line between the two stations.
The object of my said invention is to provide automatic means, partly mechanical
and partly electrical, for controlling the working of the signalling appliances and
telegraph instruments.
In order that my said invention may be more clearly understood I will describe
the same with reference to the accompanying drawings.
In Figure 5 P is the ordinary telegraphic instrument at present in use to which
is applied the lock J to be hereinafter described and which forms one part of my
said invention. The whole of the appliances shown in Figure 5 are supposed to be
located at the advance station. The signal lever B A with the electro magnet B B¹
shown at the right hand (Figure 5A) is supposed to be located at the rear station
which is also provided with a telegraph instrument as in the advance station.
In Figure
BA is the ordinary signal lever provided with a catch rod CR
which engaging with depressions CR in the casing in which the lever works
prevents it being moved forwards or backwards until lifted by pressing the lifting
handle CR against the handle of the signal lever in the usual manner.
According to another part of my said invention 1 provide an angular catch BD
pivoted in a bracket secured to the signal lever. The catch BD shown detached
at Figure 4 is so formed that the weight of the upper horizontal arm (on which
I preferably cast a letter S) suffices to keep the lower arm engaged with a
notch BE in the catch rod CR and thus prevents the lifting of the latter and the
consequent release of the signal lever. At BBI provide an electro magnet which
is connected by wire with an electrical switch L at the advance station (see
Figure 5) in such a manner that the circuit is closed and the magnet thereby
excited by the action of the handle K at the advance station.
The armature BC of the magnet is pivoted in suitable bearings at BC

page_text: (Figure 4B) and is provided with a tail rod or plate BC' (Figure 4) on which
rests the horizontal arm of the catch BD when the lever BA is at rest in its
normal forward position with the signal at danger. When the parts are in the
position shown to the left hand of Figure 4 the signal lever B A cannot be pulled
back into the position shown in dotted lines at the right of Figure 4 (which it has
to assume in order to allow a train to pass) on account of the catch BD preventing
the release of the catch rod C R. When however the man in charge of the advance
station signals "line clear" the mere fact of doing so completes the circuit (by
means of the switch L Figure 5) through the electro magnet B B in the rear
station. The armature is thereby attracted to the magnet the projecting tail
rod B C¹ rises and lifts the catch B D clear of the notch BE in the catch rod CR
as indicated by dotted lines. The armature BC is provided with a balance
weight BW adjustable on a rod or bar in such a manner as to nearly counterbalance
the catch B D.
When the signal lever is in the position shown in dotted lines at the right of
Figure 4 it can be released by pressing on the short upper prolongation of the
catch BD and then raising the catch rod CR in the usual manner.
Figure 3 illustrates the means for operating the plunger W from the signal
lever A B of the advance station. The lower end of the signal lever is formed as a
bell crank lever the lower arm of which engages by means of a stud or rod A D
with a fork in the radius rod AC from, which extends a link A H connected with
the lever, AI to which the plunger W is connected. At the bottom of the figure
is shown an alternative device to be used where two or more-signals affect the same
block as is the case at junctions. In this case the signal lever only directly acts
to raise the plunger Ŵ the weight of the parts being depended on to ensure its
descent.
Figures 1 and 2 show to a larger scale the interior of the lock J (Figure 5) some
of the detached parts of which are shown in isometrical projection in Figures 2
2B, 2º, 2º, 2º and 2". Referring to Figure 11 is the barrel of the ordinary
telegraph instrument used in connection with block signalling operated by a
handle K which is moved in opposite directions to telegraph "line clear" or "train
on line." On the underside of the barrel II attach a tongue G by means of the
pin H in such a position that when the handle K is set at "line clear" it causes
the metal spring or switch L to make contact between the block M and the
block N thereby completing the circuit in which is the electro magnet BB of the
rear station and enabling the signal lever therein to be operated if required.
Figure 1 shows in full lines the position of the parts in the lock when in its
normal position with the needle of the telegraph instrument midway between the
"line clear and train on line positions. On receipt and acceptance of the
"be ready" signal from the rear station the handle K is pushed to the left when
the parts assume the position shown in dotted lines and the signal "line clear is
given to the rear station. On the barrel I is mounted a segment F towards which
the horizontally sliding bolt E is pressed by an indiarubber band R or a suitable
spring. When the barrel I is turned to "line clear" the bolt E shoots forward
and takes under the end of the segment I and retains it in the dotted position. To
release the barrel the bolt E is slid back by hand by means of the knob El
(Figure 5) projecting through a slot in the casing of the lock. The rear edge of
the segment is preferably formed with an inclined surface corresponding to a
similar incline on the upper face of the end of the bolt E.
"
"
D is a vertically sliding bolt drawn downwards towards the segment F by a
rubber band R¹ or other suitable spring. When in its normal position as in
Figure it does not interfere with the action of the segment F.
The other elements of the lock are a swinging quadrant C pivoted at C¹ in a
bracket C and hinged at B to the locking slide B which is continually pressed
downwards by the spring B². A lever SL pivoted at SL and provided with a
spring S bears at SL² on the swinging quadrant C and tends to push the bolt B
forwards.

page_text: On receipt of notice from the rear station that the train has been permitted to
pass to the section between the two stations the handle K is turned to the right
whereupon the bolt D falls and the locking slide B shoots forward into the position
shown in full lines in Figure 2. The bolt D (preferably provided with an inclined
surface corresponding to a similar incline on the front edge of the segment F)
effectually prevents the handle K being shifted to line clear and the locking slide B
at the same time prevents the bolt D from being lifted to clear the segment F.
To enable the lock to be restored to its normal position the plunger W has to come
into operation. The upper part of the plunger which works through the lock in
the guide W2 has a hinged catch W X pressed towards the quadrant C by the
spring W³ and so shaped that as the plunger rises the hinged catch W X can yield
as it passes the curved under face of the quadrant C but as it descends the flat under
surface of the hinged catch W X comes in contact with the flat upper edge of the
quadrant C and causes it and the locking slide B to assume the position indicated
by dotted lines in Figure 2. In this position the bolt D can be raised (since in this
position the locking slide B can only swing about its hinge pin B¹) by means of the
knob D' (Figure 5) passing through a slot in the lock case.
The handle K may
then be set at its normal position as shown in Figure 1. An indicator Z is attached
to the under side of the locking slide B and has red white and green or other
conventional coloured dots r wg which successively come opposite an opening O' in
the lock case to indicate the position of the lock.
It will have been seen from the herein before given description of Figure 3 that
the only means of releasing the lock is by first raising the plunger W by setting
the signal so as to let the train "out of section" i.e. past the advance station and
then depressing the plunger W by setting the signal back at danger after the train
has passed. Until this operation has been completed the telegraphic instrument
remains locked and it is impossible for the man in charge to communicate "line
clear to the rear station; and until the circuit of the electro magnet BB is
completed by this signal it is impossible for the signal lever of the rear station to
be moved so as to lower the signal for another train to pass.
"
The segment F1 (Figure 2) is intended to be used instead of the segment F when
the lock J is applied to those telegraph instruments in which the indication of
"line clear" and "train on line" is made by two forward motions. In this case the
bolt E is dispensed with. The part G for making contact is however used in both
cases.
Protection of trains or obstructions shunted on opposite lines to allow other trains
to pass is effected by "blocking back" prior to being so shunted and should the
signalman forget such obstructions he will be unable to give "line clear" and his
attention will at once be attracted to the fact of something being wrong and
he will be prompted to find out the cause of his telegraphic instrument being
locked.
"
The letter S on the part B D signifies "section" and is a reminder to the man in
the rear station to make sure that the train has been duly "sectioned and
acknowledged by the advance station before he replaces his signal at danger.
Each of the two parts of my said invention may be used independently of the
other so that in the event of the electrical connection between the signal lever in
the rear station and the automatic switch in the advance station becoming deranged
the lock which controls the telegraph instrument is still operative.
The advantage of my said invention is that it may be readily applied to existing
telegraphic instruments and signal levers and entails no attachments to or modifica-
tions of the permanent way. I am aware that electrical appliances for locking
signal levers have hitherto been used and I make no general claim to such
appliances.
A casing or shield provided with a suitable slit through which the signal lever
can pass is used to cover the electro magnet B B and the catch BD when the
signal is at danger. These parts are then inaccessible and cannot be operated by
hand.

page_text: 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. An automatic mechanical locking device applicable to the telegraph instruments
used for block signalling on railways substantially as hereinbefore described with
reference to Figures 1 2 and 3 of the accompanying drawings.
2. The combination of parts for preventing the signal lever in the rear station
being operated, until automatically unlocked by the action of communicating "line
clear" from the telegraphic instrument in the advance station substantially as
herein before described with reference to Figures 1, 2 and 4 of the accompanying
drawings.
3. The use in combination of the locking devices set forth in Claims 1 and
substantially as and for the purpose hereinbefore set forth and shown.
Dated this 15th day of July 1893.
EDWARD TURNER WHITELOW,
70, Deansgate, Manchester, Agent for the Applicant.