New and Improved Electric Lock and System of Electric Locking, for the Purpose of Securing Additional Safety in Railway Signalling.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
New and Improved Electric Lock and System of Electric Locking,
for the Purpose of Securing Additional Safety in Railway
Signalling.
JAMES FREDERICK WALTER MORRIS 20 Grummant Road, Peckham, S.E.
Electrical Engineer, and. GEORGE MUMFORD, 166 Lordship Lane, East Dulwich S.E.
Railway Signalman, do hereby declare the nature of this invention to be as
follows:-
A pivotted tumbler arranged in a metal case, or frame is so adjusted that its
normal tendency is to fall into. a suitable slot in a tappet whenever it presents
itself.
It is secured while in this position by an armature until such time it is released
by a current being passed through an electro magnet, and so permitting it to. be
pushed out of the tappet by the usual movement of the lever.
The lock in returning to its normal position is assisted by suitable springs, which
serve as aids to gravitation. These also act as electric contact makers & breakers
used in the general manipulation of the instrument.
The lock is designed to work in connection with point detectors fouling bars,
outlying points, level crossing gates and in connection with block signalling
instruments &c.; either singly or collectively, after the manner herein described.
When used with point detectors and fouling bars its action is similar to the usual
method; but with distant points, its action is somewhat similar to ordinary wire
locking apparatus.: yet dispensing with a considerable amount of the existing costly
mechanism at the same time indicating to the signal box connected up to them,
their true positions and if properly locked or closed."
When connected up to level crossing gates, it will enable them to be controlled
subject to the conditions of the section, so that the gates can be locked, while
the train is in the section, or about to enter it, and can be kept locked until the
train has passed, and the signal man at the nearest box released them.
When arranged as a lock and block appliance the releasing of the lock can. be
done direct, as is usual or preferably as follows.--
At each signal box, for both up and down lines, we arrange local circuits, by
placing a battery in a convenient place one of the poles of which is placed to
earth and the other connected up to certain points, fouling bars, signais, gates
or other apparatus that it is desirable should be in some definate position to
guarantee the safe passage of trains: eventually completing the circuit at the
block signal instrument in the box, which instrument is controlled by the stations
in advance.
These conditions being favourable and only when so, the signal-ınan can with the
aid of a suitable circuit closer complete a circuit which traverses an electro-magnet,
thereby unlocking certain points or signal levers, as may be required.
"Train
If the instrument of the advance station indicates "Line clear" or
accepted" the signal can be placed to "Danger" if necessary, in face of the
approaching train.
In existing systems, the signal levers being connected mechanically to the
"Line clear will be
signalling instruments the signal having been thrown up,
indicated at the rear station.. This invention enables the signal to be put to

page_text: Danger" and when the train has been examined the signal can be lowered to
allow it to proceed; and without giving power to clear the road until the train has
been properly disposed of.
To complete the local circuit it is preferable to use a contact attached to and to
work with the catch lever in drop box, thereby dispensing with any additional
movements, by the signal-man and rendering it impossible to operate more than one
contact at a time.
}
Another local circuit it arranged in the signal box somewhat after the manner
of that mentioned above. A contact breaker is placed in the circuit, which
traversing certain coils controlling the handles, dials or other appliance thereby
makes the display of these different instruments subject to the working of the
lock..
The former local circuit was closed on the indication of "Line clear." This
second local circuit only finds "earth" when "Train on line" is shewn on the
instrument or at its normal position.
It is by this arrangement that an approaching train can be stopped as above and
can only be stopped while the advance instrument indicates "Line clear;" but as
soon as the position of the advance instrument is altered to "Train on line" this
power ceases: If the lever be now returned it becomes locked, at the same time
closing a circuit and releasing the handle or other arrangement and so enable the
"Train passed" signal to be given.
These local circuits may be closed, if preferable, and not as described above;
but the manner detailed is simpler. The lock can readily be attached to any block
signal instrument already in use and while retaining the good points of such
systems and enabling them to fulfil the conditions of such gear, it introduces extra
safe guards and improvements not hitherto attempted.
The above arrangement describing the stopping of approaching trains, without
operating the circuit which gives "Line clear" is due to the substitution
of electrical for the usual mechanical devises, which unfortunately, for the
requirements of signalling operates at all times, the same, thus. When the signal
is thrown up in front of a train the mechanism is worked exactly as if the train
had passed out of the section.
The lock is enclosed in a casting or metal framing beneath the floor of the signal
box and there being no mechanical connections with the instruments above, it is
impossible for the signalman to tamper with it.
It can readily and cheaply put into operation, easily attached to any kind of
frame and in some cases, worked with existing tappets.
It can be worked with advance signals or with treddles if necessary, but these are
not advantages to our invention a number of levers being worked as easily
as one.
While providing more safeguards than any existing system it is done without
adding to the number of instruments in the signal box and in some cases reducing
them. The application of our invention confers an important improvement into
the existing block instruments, inasmuch as it guarantees that the three signals
shall be properly given and answered before unison between the boxes can be
obtained, then it is not possible for the signalman to clear the rear section until
be has passed the "Train on line" signal to the advance station.
It follows that he cannot forget to give the "Train on line" signal, otherwise
the rear section must remain blocked.
This removes one of the possibilities that has been the cause of many disasters.
Another important feature in this invention is that in the event of any accident
occuring to the mechanisms, such as broken wires, loose terminals & c.: the result
will not be attended with disaster through releasing of the signal :-but will lock it
and so rob any such failure of danger.
Dated this 1st day of February 1895.
JAS. F. W. MUKKID.
GEORGE MUMFORD.

page_text: New and Improved Electric Lock and System of Electric Locking,
for the Purpose of Securing Additional Safety in Railway
Signalling.
We JAMES FREDERICK WALTER MORRIS of 20 Grummant Road Peckham
S.E. Electrical Engineer, and, GEORGE MUMFORD of 166 Lordship Lane
East Dulwich S.E. 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 :-
The improved locking mechanism according to our invention comprises a
pivotted tumbler arranged in a metal case, or frame and so adjusted that its normal
tendency is to fall into a slot in a tappet or locking bar whenever it presents itself
in position to receive it.
The tumbler is retained in this position by the armature of an electro magnet
until such time that a current is passed through the said. electro-magnet, and so
permitting the tumbler to be pushed out of the slot in the tappet or locking bar by
the usual movement of the operating lever.
The parts of the lock in returning to their normal position may be assisted by
the general
springs, which act as electric contact makers and breakers in
manipulation of the instrument.
The lock is designed to work in connection with point detectors, fouling bars,
outlying points, level crossing gates and in connection with block signalling
instruments and the like, either singly or collectively, in the manner hereinafter
described.
When the lock is connected up to level crossing gates, it will enable them to be
controlled subject to the conditions of the section, so that the gates can be locked
while the train is in the section, or about to enter it, and can be kept locked until
When
the train has passed, and the signalman at the nearest box releases them.
arranged as a lock and block appliance the releasing of the lock can be done direct,
as is usual, or preferably as follows:-
At each signal box, for both up and down lines, we arrange local circuits by
placing in a convenient place a battery, one of the poles of which is connected to
earth and the other connected up to certain points, fouling bars, signals, gates or
other apparatus that it is desirable should be in some definite position to guarantee
the safe passage of trains, eventually completing the circuit at the block signal
instrument in the box, which instrument is controlled by the stations in
advance..
These conditions being favourable and only when so, the signalman can with the
aid of a suitable circuit closer complete a circuit which traverses an electro-magnet
thereby unlocking certain point or signal levers, as may be required.
"
If the instrument of the advance station indicates "Line clear or "Train
accepted" the signal can be placed to "Danger" if necessary, in face of the
approaching train.
In existing systems, the signal levers being connected mechanically to the
signalling instruments the signal having been thrown up, "Line clear" will be
indicated at the rear station. This invention enables the signal to be put to
Danger" and when the train has been examined the signal can be lowered to
allow it to proceed, and without giving power to clear the road until the train has
been properly disposed of.
66
To complete the local circuit it is preferable to use a contact attached to and to
work with the catch lever or drop box, thereby dispensing with any additional

page_text: movements, by the signalman, and rendering it impossible to operate more than one
contact at a time.
Another local circuit is arranged in the signal box somewhat after the manner
of that mentioned above, which traversing certain coils controlling the handles,
dials or other appliance, makes the display of these different instruments subject to
the working of the lock.
The former local circuit was closed on the indication of "Line clear." This
second 'local circuit only finds"-earth "when "Train on line "is shewn, or when the
instrument is in its normal position.
It is by this arrangement that an approaching train can be stopped, it being
possible to replace the lever and re-operate it as often as may be required while
the advance instrument indicates "Line clear," but as soon as the position of the
advance instrument is altered to "Train on line" this power ceases. If the 'lever
be now returned it becomes locked, and at the same time closes a circuit and
releases the handle or other arrangement and so enables the "Train passed" signal
to be given. The lock can readily be attached to any block signalling instrument
already in use and while retaining the advantages of such systems, it introduces
'extra safe guards and improvements not hitherto attempted.
The above arrangement describing the stopping of approaching trains without
operating the circuit which gives "Line clear" is due to the substitution of
electrical, for the usual mechanical devices, which unfortunately, for the require-
ments of signalling operates at all times the same, 'thus-when the signal is thrown
up in front of a train the mechanism is worked exactly as if the train had passed
out of the section.
The lock is enclosed in a casing, and there being no mechanical connections with
the instruments above, it is impossible for the signalman to tamper with it.
'It can be readily and cheaply put into operation, easily attached to any kind of
frame and in some cases, worked with existing tappets.
It can be worked with advance signals or with treadles if necessary, but these
are not advantages to our invention a number of levers being worked as easily
'as one.
While providing more safe-guards than any existing systems it is done without
adding to the number of instruments in the signal box and in some cases reducing
'them. The application of our invention confers an important improvement into
the existing block signalling instruments, inasmuch as it guarantees that the
proper signals shall be given and answered before unison between the boxes can be
obtained, and it is not possible for the signalman to clear the rear section until he
has passed the "Train on line "signal to the advance station.
It follows that the signalman cannot forget to give the "Train on line" signal,
otherwise the rear section must remain blocked.
This removes one of the possibilities that has been the cause of many disasters.
Another important feature in this invention is that in the event of any accident
occurring to the mechanism, such as, broken wires, loose terminals, &c. the result
will not be attended with disaster through releasing of the signal, but will lock the
signal and so rob any such failure of danger.
And in order that our said invention may be fully understood we shall now
proceed more particularly to describe the same and for that purpose shall refer
to the several figures on the annexed sheets of drawings, the same letters of
reference indicating corresponding parts in all the figures.
.
Figure 1 represents in elevation an arrangement of our improved locking device
with a signal or point operating lever and locking bar or tappet.
Figure 2 is a longitudinal vertical section of the lock the parts being in their
normal or unoperated positions.
Figure 3 is a similar view of the lock shewing the parts in their operated
position.
Figures 4 and 5 are transverse vertical sections of the lock, taken respectively
along the lines 1-2 and 3-4 Figure 3.

page_text: Figure 6 is an elevation of a needle instrument for signalling trains to an advance
station and
Figure 7 is an elevation of a needle instrument for receiving trains.signalled from.
a rear station.
Figures 8 and 9 represent in elevation and plan respectively special apparatus
operated by the spring catch of point lever for directing electric currents and
making and breaking electric contacts.
Figure 10 is a plan of an arrangement for directing and controlling electric
currents, for use where several levers are employed for transmitting to one
advance station, which, while permitting repeated operations render it impossible
to substitute one lever for another.
Figure 11 represents in elevation an instrument for use in connection with.
advance sub-sections for indicating sub-section clear or blocked.
Figure 12 shews the interior of the instrument with the indicator shewing the
sub-section clear, and
Figure 13 is a similar view shewing the indicator sub-section blocked.
Figure 14 is a diagram illustrating the circuits controlling the locking mechanism
and the signalling instruments and the contacts for completing and breaking the
circuits.
A Figure 1 is an ordinary signal or point lever, B our improved lock and C.a
contact maker operated by the drop box or spring catch D of the lever.
The lock mechanism is enclosed in a box or casing B Figures 2 and 3 in the
interior of which are secured two metal blocks B2 in which is mounted a spindle D2.
carrying a tumbler or cam E, which by gravitation assumes the normal position
shewn in Figure engaged in a slot or opening F in or otherwise engaged with the
tappet or locking .bar G thereby securing the said tappet or locking bar against
longitudinal movement. H are the coils of an electro magnet the armature 1 of
which is pivotted at K and has a depending arm K2 and block K³ which engages
with the cam or tumbler E and in notches in the blocks B2 to retain it in its normal
position. The armature also has an extension 1 for acting on a spring or springs L
for making and breaking or directing electric currents in connection with interlocking
and controlling circuits.
M is an electro magnet for controlling the operations of the signalman. The-
armature N of this magnet is pivotted at n and is connected at its upper end to a
spring tending to hold the armature away from the pole of the magnet. P is a
lever which in its normal position rests at one end on the spindle D and its opposite
end is in position to prevent the armature N from moving outwards under the action
of the spring O. On the spindle D² which carries the tumbler or cam E is a pin or
projection d which when the tumbler is moving into the position shewn in Figure 3
turns the lever P on its fulcrum so as to remove its end out of the range of the
armature N and admit of the end of the armature passing over the end of the
lever P and so lock the said lever in this position as shewn in Figure 3.
QQ are springs for making and breaking contact with contact points 9 92 for
directing electric currents, the springs Q tending always to make contact with the
points for the purpose hereinafter described-and the spring Q always tending
to make contact with the point 9-these contacts are however controlled by the
movement of the armature N. The springs Q bear on an insulated piece R on
the armature and the spring Q2 is adjustable by means of a screw S nearer to or
further from the contact point q² as required.
In connection with an ordinary needle block instrument, (such as is shewn by
Figure 6) on which all trains would be signalled to an advance station, we employ
a "polarized relay "which is affected by certain currents received from the advance
station; but is not affected by the currents sent, when this instrument itself is
operated. To this instrument we attach additional springs T which are operated
by the two ordinary springs t when the handle is moved, on which springs twe
provide insulator blocks t against which the springs T bear. When the handle is
in its normal position, the two springs T are in contact with the pillar U and au

page_text: electric current can pass from one spring to the other, but when the handle is
moved in either direction, the said springs T are moved by the insulator blocks t²
out of contact with the pillar U and the current is broken.
.
In connection with another ordinary needle block instrument, on which all trains
from a rear station would be received, we provide a bolt V by which we secure
the bandle in the "Line clear" position, and with a bolt V2 to secure the said
handle in the "Train on line" position. In the bolt-V2 is a slot v to receive the
end u of the armature of the electro-magnet in the instrument, and so prevent
the movement of the bolt V2 until a current is passed through the magnet. z is a
gravity latch, which, when the armature end wis withdrawn froin the slot v keeps
it from returning to the slot till the bolt is operated.
The apparatus illustrated by Figures 8 and 9 is that which we prefer to employ
for making and breaking, or directing electric currents by the movement of the
point or signal lever and comprises a base plate a from which projects upwards a
side plate and a bearing block e in which is mounted a spindle d² carrying a
came and an operating lever f. Pivotted to the side plate bare two levers y g³
arranged to bear on diametrical opposite sides of the periphery of the cam e, and
held in contact therewith by a spring h. Each lever gg2 carries a block 93 of
insulating material on which bear two springs i 2 carried by, but insulated from
the plate b. The cam e is provided with an arm e² connected to a spring e³ which
tends to maintain the cam in its normal position. kl and m are contact points with
either of which as required, the springs i may by the movement of the came
be caused to make contact so as to direct the electric current in the direction
required.
Our improved locking device can be used in connection with points, fouling
bars, gates, signals and the like as an interlocking apparatus, and in combination
or not with block signalling and like instruments either singly or collectively as
may be required.
When the locking device is combined with block signalling instruments, the
combination constitutes a "Lock and block" instrument which will fulfil all the
conditions, and guarantee all the safe-guards hitherto associated with lock and
block apparatus of the best kind but with important improvements.
For convenience of describing the operation of our invention we will suppose
there are three signal cabins, which we will refer to as A, B, and C, and assume
cabin A to control the advance section; cabin B the one in which we are situated;
and cabin C to be at the entrance of the rear section; it follows of course, that
although this description is chiefly confined to cabin B, the same conditions would
prevail at the other two cabins, or any number of additional cabins.
There is provided at each cabin a local lock circuit in which we can include
certain points, fouling bars, gates, signals, or the like, which it is desirable_should
be in some definite position necessary for the safe passage of a train.
This will be understood by reference to the diagram Figure 14 in which H2
represents the local battery in connection with the coil H of the locking device
illustrated in Figures 2 and 3. C is the contact maker described in detail with
reference to Figure 8 and operated by the spring catch D of the lever A illustrated
in Figure 1. C2 represents a similar contact maker as applied for use with points
signals and gates either singly or collectively as may be necessary. Y is the
polarized relay hereinbefore referred to and which is excited by the current
received from an advance station, and when the "Line clear" indications are given
is caused to make contact at y, thereby closing the local circuit through earth or
otherwise.
Z represents the arrangement of springs T described with reference to Figure 6.
When it is desirable to control several signal or point levers, the locking circuit
is made subject to the springs QQ as explained with reference to Figure 10.
The springs L (Figures 2 and 3) are also used in connection with interlocking
when it is desirable that conflicting levers be properly locked before certain other
levers can be operated. When all these conditions are satisfactory, the signalman

page_text: can by moving the spring catch D of lever A, or other suitable menus, make
contact in the apparatus Figures 8 and 9 so as to complete the circuit, which will
release his starting or other lever.
A second local circuit is provided to control the signalman in his movements,.
reudering it imperative for him to go through deliberately, all the movements, that
are necessary to properly dispose of a train, before he can give "Line clear"
accept a second train.
"
ΟΙ
For example we will suppose that a train is approaching C cabin the signalman
at this cabin will signal to cabin B the "Be ready' oľ "Warning" signal; if the
signalman at B is ready he will acknowledge it by moving the handle of the
receiving instrument Figure 7 and peg over the handle by the bolt V so that
the needle points to "Line clear."
When the train passes cabin C the signalman there will signal to B cabin
"Train entering section" the signalman at B cabin will acknowledge, and peg the
bandle of the instrument Figure 7 over by means of the bolt V2 so that the needle
points to "Train on line." To secure the handle in the "Train on line " position,
the bolt V2 must be so moved, that the slot v comes directly under the armature
end w the gravity latch being automatically pushed aside by the armature to
admit of the armature entering the slot and so secure the bolt until a current is
passed through the coils of the magnet 2 whereupon the armature will be
removed from the slot and the gravity latch fall into position to prevent its
re-entrance.
77
The train now being in the section, the signalman at B will give the "Be ready
signal to cabin A, the signalman there will acknowledge signal, and peg the handle
of his receiving instrument over in the position to indicate in his own cabin and iu
cabin B Line clear." The relay in connection with the instrument at cabin B,
will be deflected by the current from cabin A, and so far as cabin A is concerned
the signalman at B will be able to lower his starting or other lever.
It will be well to remember, that, the lock circuit, includes as before stated,
points, gates, and the like; in the description we assume these to be in their proper
position, only referring to them at times, as "other condition."
The instrument operated by the signalman at cabin A now indicates "Line clear"
so that the signalman at cabin B can lower bis signal, that the train may enter
advance section; he thereupon lifts the spring catch D of the lever A. (see Figure 1)
thereby closing the circuit by contact 1 Fig. 8 and passing a current through coils H
Figure 2. The armature I being thus attracted causes the arm K2 and block K²
extension 12 and springs L to take up the position shewn in Figure 3.
The lever A can now be pulled, the movement of lever shifting the tappet or
locking bar G and turning the tumbler or can E into the position shewa in
Figure 3. and the pin d acting on the lever P, releasing the armature N of the
controlling magnet M which armature by the force exerted by spiral spring O, takes
up the position shewn in Figure 3. thereby moving the springs Q out of contact
with the point and placing the spring Q2 in contact with the point q² the
parts remain in this position till a current is passed through the coils of the
magnet M.
Should the signals not come properly off, the lever can be returned and a second
trial made, or should it be necessary for the signalman at B cabin to stop the
approaching train he can put the signals to danger and lower them again repeatedly
if necessary, during the whole time the advance instrument indicates "Line clear."
During these repeated movements the armature N with its attachments remain
unaffected, and still retain the position shewn in Figure 3, this facility is due to the
substitution of an electrical controlling apparatus for the mechanical contrivance
usually employed, and which for the requirements of railway signalling, always
perform the same operations, no matter for what purpose the lever may be
returned.
When the train passes cabin B. the signalman there signals to cabin A.
"Train entering section" which the signalman at cabin A acknowledges and pegs

page_text: his instrument over; so that it indicates in his own cabin and in cabin B "Train on
line," should the lever A be returned now, it will be locked so that the signalman
at B cabin, can no longer release by his spring catch D, the relay not making
contact at the right point.
When the signalman at cabin B altered his instrument to indicate "Train on
line in his own cabin and in cabin C it was secured in that position by the bolt V2
which in its turn was secured by the armature end w entering the slot v Figure 7.
It is now that the controlling circuit comes into operation as will be understood' by
reference to Figure 14 in which M2 is the local battery connected with the coils M
of the controlling magnet Figures 2 and 3. Land are the springs described
with reference to Figures 2' and 3. are the coils of the magnet referred to with
reference to Figure 7 for controlling the handle or dial of the block signalling
instrument Y the polarized relay through which the current from an advanced
station passes when Train on line" signal is given, causing the armature to make
contact at y which is the normal position of the armature thereby placing the
controlling circuit to earth or otherwise closing it and breaking, the lock circuit
at y:
The circuit is made and broken by the spring or springs L Figures 2 and 3 which
spring breaks the circuit when the lock is released, and completes the circuit when
the lock resumes its normal "locked"" position. The circuit is also inade and
broken by the spring Q which as will be seen by Figure 2 breaks the circuit when
the armature N is held by catch lever P but completes the circuit when the
armature N is in the position shewn in Figure 3. This circuit can be completed
and broken at four places, namely at the springs L, the spring Q2 Figure 2. the
springs T, Figure 6, and at the relay. It does not matter in what order these
contacts are made to complete the circuit, but as soon as it is completed, the current
passes through the coils of the magnet M and attracts armature N and with it the
springs and Q, breaking its own circuit at q². The same current simultaneously
passing through coils of the magnet Figure 6 in the receiving instrument withdraws
the armature w from slot v and is kept from returning to the slot by the gravity
latch z. The signalman at cabin B' is then free to signal to cabin C "Train passed."
The controlling circuit like the lock circuit can be made to include point siguals
and the like if desired. The locking mechanism may if desired be separate from
the controlling mechanism and be worked by one lever, the controlling mechanism
being worked by a separate lever. For interlocking; the controlling section can be
dispensed with entirely.
Where keys and other special appliances are employed, and the apparatus_is
stated to work with the greatest precision, and be an effectual check upon the
actions of the signalman, there is nothing to prevent him from using these different
appliances to work them as he pleases, whereas in working according to our system
special appliances such as keys, movement of levers or the like for working the
apparatus when the ordinary operation have only been imperfectly carried out, are
dispensed with. We also discriminate between permission for a train to enter a
section and when one has actually entered.
When permission to enter is asked for and given by the "Line clear" indications,
the desire to enter can be cancelled freely. Should the train pass, and "Train
entering section "
signal be given, cancelling becomes impossible, and it is
absolutely necessary for a man, who has received a "Train entered section" signal,
to deliberately and properly dispose of it, before he can be in the position to accept
another.
The explanation hitherto given, applies to the simplest form of signal cabin,
where one lever only is required to be operated. Figure 10 illustrates the
principle we adopt and work at junctions and terminal stations, where trains can
enter one advance section from many different points, the different signals all being
controlled by one advance instrument.
Referring to Figure 10 the springs Q are those operated by the controlling
armature N, Figure 2 and 3, and it will be obvious that whenever a lock is

page_text: operated, one pair of springs Q are switched out and contact can only be success-
fully made a second time at this point, until a current is passed through the
coils M as herein before explained.
1
Figure 10 represents three pair of these springs those marked Q are connected
with the battery and those marked Q¹ are connected to the line wire, it will be
seen by the battery sign + that a current passes from the bottom of first.
spring marked Q out at the top then to bottom of second spring marked Q and so
on throughout the series, eventually terminating in a disconnected end. The line.
wire is connected with the bottom of opposite spring marked Q₁ the same
arrangement being repeated in an inverse manner; it will be readily seen if
connection is made at either place marked ✗ a current would pass from the
battery to the line wire, and so to earth, always missing the pair of springs where
contact is made, but passing through one of each of the others.
For instance, should contact be made at X at No. 2 pairs of springs a current
would pass through the Q spring of No. 1 pair, miss No. 2 pair of springs, and
pass through the Q¹ spring of No. 3 pair. Should contact be made at X No. 3 pair
of springs, a current would pass through the Q springs of Nos. 1 and 2 and to line
in No. 3 suppose there were a great number of locks and one of the centre one's.
were operated the current would pass through the springs Q of all the locks on the-
battery side and the springs Q' of all the locks on the opposite side the one first
selected effectually preventing all the others from being used, but retains the-
freedom hitherto explained of itself being repeatedly used if necessary.
.
"-
Our invention is applicable to what is technically known as point locking
the object being to prevent a signalman accepting a train, while shunting operations.
are going on; or on the other hand, to prevent shunting operations from being
resumed after a train has been accepted.
"
Our invention can also be worked in connection with "advance subsections the:
signalman in this case being compelled to record the entry of every train otherwise.
the rear section must remain blocked.
Our improved locking device can be connected so that outlying points, gate &c..
may be controlled from the signal cabin.
3-
The instrument illustrated by Figures 11, 12, and 13, for indicating when an
advance subsection is clear and when blocked contains a contact point k connected
with the local lock circuit and a contact point k² connected with the controlling-
circuit a spring completing one or the other circuits according to the position of
a lever m' carrying the indicator dials. While the instrument indicates "Clear"
all signals admitting to the subsection will be free. When a train enters subsection
the signalman must turn the handle n so that the dial with the word "Blocked".
appears at the opening o in the front of the instrument the signalman in this case-
being compelled to record the entry of every train otherwise the rear section must.
remain blocked; pp² are stops to govern the movement of the lever m².
The springs T Figure 6 can be used for the purpose of intercepting currents in.
the local lock and controlling circuits so as to prevent the signalman (while using
his own instrument) from affecting in any way, either of these circuits as no current.
can pass through the springs T from the pillar V except when the handle of the
instrument is in a perpendicular position.
This
By the ordinary mechanical methods of interlocking, the position of the various
point and signal levers only, are determined; the position of the corresponding
points, signals &c. being left to mere chance; should the point rods break, or
signals hang off complication may arise which may lead to grave disaster.
defect is recognised and various appliances are made use of to overcome the
difficulty; such as point detectors &c. these acting in conjunction with the
mechanical interlocking of the frame.
By attaching one of our contacts (Figure 8) to the various points siguals &c.
affected, and by fixing to the various levers one of our locks, or two where back
locking is required (the controlling portion of the mechanism being omitted) a
system of interlocking is provided which in addition to the usual safeguards will
B

page_text: ensure that the point signals &c. operated, shall be in a perfect position corre
sponding with their respective levers, before conflicting levers or the like can be
moved. By making use of springs L (Figure 2) and the novel arrangements of
circuits illustrated by (Figure 10) whole frames, and signalling stations on this
principle can be fitted up with a most effective and complete interlocking
apparatus.
The special form of contact shewn in Figure 8 can also be used for obtaining
electrical contacts by the deflection of the rail for the purpose of signalling the
approach of trains generally, and the came may be made to operate several levers f
if desired.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:
-
1. In a locking device for use in railway signalling a pivotted cam or tumbler
having a normal tendency to engage with a tappet or locking bar an electio
magnet having an armature which tends normally to engage the cam or tumbler
so as to retain it in engagement with the tappet or locking bar the said armature
being removed out of engagement from the tumbler when a current is passed
through the magnet and thereby permit of the tumbler being removed out of
engagement with the tappet or locking bar by the movement of the signalling or
point lever in the ordinary manner substantially as herein before described.
2. The combination with the subject matter of the preceding claim of a spring
or springs operated by the armature of the electro magnet when attracted so as to
make or break electric contacts for interlocking and controlling circuits substantially
as and for the purpose herein before described.
3. In a locking device for use in railway signalling the combination with the
subject matter of the first claiming clause of an electro magnet, spring contacts
and lever operated by the tumbler for controlling the operations of the signalman
substantially as hereinbefore described.
4. The combination with the locking device herein before described of the various
arrangements of spring contacts and switching apparatus described, by means of
which the proper position of signals, points, gates and the like, together with the
handles & dials, or the like, of block signalling instruments are determined and
secured, substantially as and for the purpose herein before described.
5. In combination with the locking device hereinbefore described a receiving
instrument provided with means for controlling the handles, dials, or the like, and
making the display of the receiving instrument subject to the conditions of the
lock substantially as herein before described.
6. The combination and arrangement of parts constituting "lock and block"
and "interlocking" apparatus substantially as hereinbefore described and illustrated
by the accompanying drawings.
Dated this 20th day of November 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.