provements in Electric Signalling Apparatus and Systems for Railways.
Year: 1893

page_text: COMPLETE SPECIFICATION
Improvements in Electric Signalling Apparatus and Systems for
Railways.
I, JAMES YATE JOHNSON, of 115 St. Vincent Street, Glasgow in the County
of Lanark, North Britain, Chartered Patent Agent (a communication to me from
abroad by) Jacob William Lattig, Electrical Engineer, and William Frederick.
Detwiller Pascoe, Manufacturer, of Easton, in the State of Pennsylvania, United
States of America 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 present invention is directed to an automatic block system of danger or
home and caution or distant signals similar to that described in my application for
Patent No. 7702 of 15th April 1893, and like the latter contemplates the
employment of an electric motor for actuating the signal operating mechanism to
move the signal to safety. The particular form of electric motor which I describe
in illustration of the invention is a solenoid or sucking magnet, to the core or cores
of which the signal actuating rod is connected.
The nature of the improvements can best be explained and understood by
reference to the accompanying drawings in which―
Figure 1, is a representation, in part diagramatic, of an automatic block system
of danger and caution signals involved in the invention.
'
Figure 2, is an enlarged view of the solenoid employed by me.
Figures 3, 4 and 5 are diagramatic representations of modified circuit
arrangements.
To illustrate the system I represent two insulated blocks or railway track
sections X1, X2, each provided with a signal pole carrying two pivoted and
""
❝ home the other distant."
counterweighted semaphore blades B, B', the one
For operating each blade there is a solenoid C, having its core or cores connected
by a rod a to the weighted end of the blade, the arrangement being such that when
the solenoid is energized its core will be drawn up, thus lifting the rod a and
moving the signal to safety. At a suitable point on each rod a is interposed a
short link a', to permit the armature or core to move up and down in the right line,
notwithstanding the slight lateral movement of the upper portion of the rod a in
rising and falling due to its connection to the pivoted semaphore blade.
Each solenoid has its spools connected at the top to an angle piece e preferably
of non-magnetic material, the vertical limb of which is bolted to the signal pole.
The magnetic yoke for the spools is shown at d. It is placed on the top of the
horizontal limb of the angle piece c, and is provided with short cores d¹ which
extend through the angle piece into the interior of the spools. The yoke is held
in place by bolts e which pass down loosely through the yoke and screw into or are
otherwise fastened to the angle piece. Encircling the bolts, and interposed between
the heads of the latter and the yoke d are springs . The object of this is to
furnish a cushion or yielding and elastic buffer for the cores to bring up against,
when they are drawn up. Other forms of elastic cushion may be employed but I
prefer the one just described for the reason that when the armature cores are in
contact with the cores d'¹ of the yoke, there will be a closed magnetic circuit, which
is particularly adapted for tractive power. Thus, after the signal has been pulled
to safety, the current in the solenoid may be greatly reduced, and still serve to
maintain the signal in that position.
To the operating rod a of the danger signal B is connected a lever 6 pivoted to
a casting 9, secured to the pole. Å like lever is connected to the rod a of the

page_text: caution signal; but this lever has no part in the electrical functioning of the
apparatus. The upper or danger signal lever b however is by a pin and slot
connection joined to a vertical rod h which is arranged to slide up and down in
guides on the casting g, and has on it two insulated contacts m², n', which operate
the one in connection with the fixed contacts m the other in connection with the
fixed contacts n.
In the path of each armature is the moveable member o of a switch which plays
between two contacts p, p', with the lower one p of which it normally is in contact.
In connection with each signal operating appliance there is a relay D, which
controls two sets of contacts x, y, the one set insulated from the other.
The circuit arrangements are as follows; for the home signal, the relay D is
included in a constantly closed track circuit 1 which is completed through the rails
of the insulated track section or block appropriate to that signal; a second circuit 2,
the signal operating circuit, includes the solenoid, and is completed through the
contacts and o, p; a third circuit 3, which we will call the locking and releasing
circuit, is a shunt around the large battery of circuit 2, and is completed through
the contacts y and o, p'. This last named circuit also includes the solenoid, and is
supplied from a smali battery of only enough power to energize the solenoid
sufficiently to hold the cores in the position to which they are brought through the
closure of circuit 2.
There is the same system of circuits 1*, 2x, 3×, for the caution or distant signal,
save that the primary circuit 1x is a grounded circuit, of which the track forms no
part, and is completed through two sets of contacts, viz.: the contacts m, m³,
controlled by the home signal of the next block in advance.
The mechanical connections are such that whenever and so long as a home signal
stands at danger the contacts m, m³, and n, n', controlled by it will be open.
In Figure 1 a train, typified at Y, is supposed to have just left section X' and to
be on section X2, travelling in the direction of the arrow.
Consequently in section ✗' track circuit 1 is closed through relay D, the latter
is energized and by attracting its armature has closed the contacts x, y. Signal
operating circuit 2 has thereby been closed, with the result of causing the solenoid
to draw up its armature, thus lowering the home signal to safety. The armature
however by the time it has moved up far enough to set the signal to safety, has
lifted the key o from contact p, thus breaking the signal operating circuit 2, and
has brought it into contact with contact p³, thus completing the locking and
releasing circuit 3, by which the solenoid is energized just enough to hold its
armature in place. By this movement the contacts m, m³ and n, nº controlled by
the home signal B have been closed.
The caution or distant signal B' however of section ✗' still remains at danger,
because while the contacts m, m¹ of its circuit 1 are closed, the contacts n, n', of
that circuit controlled by the home signal of section X² still remain open, this being
due to the fact that as the train Y is still on section X2, the track circuit 1 of that
section is completed through the path of lower resistance offered by the wheels and
axles of the train, thus cutting out the relay magnet D of section X', and
consequently putting both of its signals to danger.
As soon however as the train Y passes beyond section X³, the signals in that
section will stand as now represented for section X, while in section ✗' the caution
signal will go to safety.
In Figures 3, 4 and 5 are shown different circuit arrangements which may be
used as substitutes for the particular arrangement of circuit 3, (the locking and
releasing circuit) shown in Figure 1, all of these arrangements having a common
object viz. to cut down, after the signal has been brought to safety, the battery
power from that required to bring the signal to that position to that requisite to
hold it in that position.
In Figure 4, for example, the shunt 3 is connected to only such part of the
battery of circuit 2, as needed to hold the signal at safety, and relay D has but one
set of contacts x.

page_text: In Figure 3, the upper contact p is dispensed with and the circuit 3 is completed
through a constantly closed shunt 3 around the contacts, containing a resistance R,
which will permit the passage of only current enough to cause the solenoid to
hold its armature at safety. Relay D in this instance also has only one set of
contacts x.
But in
In Figure 5, the relay D as before controls only one set of contacts x.
this figure, the circuit arrangements differ from any shown in the preceding figures
in that the solenoid is cut out as soon as it has done its work, and an electro-
magnetically controlled detent or lock is relied on to hold the signal in the safety
position to which the solenoid has brought it.
To this end the locking and releasing circuit 3 is in a shunt from the main
operating circuit 2, around the solenoid, and is completed through the upper
contact pl; and it includes a locking and releasing magnet E, and a resistance R.
so proportioned as to permit the passage of only current enough to energize properly
the magnet E.
The magnet E is mounted in a box F secured to the signal pole, in the line of
the signal operating rod a which passes through the box as shown. Pivoted to the
box is the armature lever E' of the magnet E, which lever on its face next to
the rod a carries a mitre-shaped nose or dog i, which, when the rod is in the position
which it occupies when the signal is at safety, registers with a like shaped notch j
on the rod a.
Under this arrangement, when the circuit 2 is closed, the solenoid will bring the
signal to safety, through the movement of its armature. By the time the signal
is at safety the armature in rising will have lifted the key o from p into contact
with p thus cutting out the solenoid and at the same time closing the shunt 3
around the latter, whereby the locking and releasing magnet E is energized and by
attracting its armature lever locks the rod a in place by the engagement of the
dog i and the notch j. This condition of affairs will continue until the circuit is
broken at x, when the magnet E will release its armature, and the signal con-
sequently will at once rise to danger.
It will of course be understood that the circuits represented in Figures 3, 4, 5 are
applicable as well to the distant signal as to the home signal.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is :-
1st. The combination of a series of home or danger signals B; a series of
circuits 1, 2, 3 for each home signal; a relay D in each circuit I controlling contacts
in the other circuits; a solenoid in each circuit 2, having its armature core or cores
connected to and adapted to operate the home signal; a series of caution or distant
signals B¹, a series of circuits 1, 2, 3x, for each distant signal; two sets of
contacts m, m², and n, n', in each circuit 1* controlled the one by the home signal
mechanism of the same section, the other by the home signal mechanism of the
section next in advance; a solenoid in each circuit 2* having its armature core
or cores connected to and adapted to operate the caution or distant signal; and
a contact controlled by the moving part of each solenoid (pertaining to both
the home and the distant signal mechanism) for successively completing each
circuit 2, 3 or 2*, 3*, appropriate to its signal, all as herein before specified.
2nd. The combination of the signal, the solenoid and its armature core or cores
connected to and adapted to operate the signal; the signal operating circuit
including the solenoid, and completed through contacts o, p', and containing the
locking and releasing magnet E; the armature lever E connected to a dog adapted
to engage the signal operating rod; and the primary circuit including the relay D
and controlling contacts through which the signal operating and locking and
releasing circuits are completed, under the arrangement and for joint operation as
hereinbefore set forth.
3rd. The combination of the signal, the solenoid having its armature cores

page_text: connected to and adapted to operate the signal, and provided with a spring yielding
yoke with cores entering the spools of the solenoid to constitute an elastic
buffer for the armature cores, substantially as and for the purposes hereinbefore
set forth.
1
די
1000
J. Y. JOHNSON,
115, St. Vincent Street, Glasgow, Applicant.