Improved Apparatus for Indicating the Position of the Arms of Semaphore Signals.
Year: 1885

page_text: Improved Apparatus for Indicating the Position of the Arms of
Semaphore Signals.
I, CHRISTOFFER RETZIUS-EKWALL of Linköping, in the County of Ostergötland,
Sweden, Engineer, do hereby declare the nature of my invention for " IMPROVED
APPARATUS FOR INDICATING THE POSITION OF THE ARMS OF SEMAPHORE SIGNALS
"'
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:-
This invention relates to electrical apparatus for indicating the position of the
arm of a semaphore signal, at a railway station or signal box and at any other
desired point on the line of railway.
In the accompanying drawing
Figure 1 is a plan, partly in section, of apparatus constructed according to this
invention, and connected with the operating lever of a semaphore, the latter being
in the position which it occupies when the signal shows "Line clear."
Figure 2 is a similar view showing the position of the parts when the signal
stands at "Stop."
Figure 3 is a view drawn to an enlarged scale illustrating the construction of
a detail.
A is the semaphore-post, at the lower end of which is a box (not shewn in the
drawing) containing a device consisting of two cylinders a and b, the latter of
which is provided with a binding-screw c.
In the cylinder a is arranged the piston d, the rod e of which at one end extends
into the cylinder b, and at the other end protrudes from the cylinder a and
terminates in the disc f. Within the cylinder a the piston-rod e is surrounded by
a spiral spring x, which tends to push the rod e outwards and away from the
cylinder b.
The part of the piston-rod è between the two cylinders carries a binding-screw g
which connects the said rod with the conducting wire h. This wire extends to an
electro-magnet 8-Figure 3-arranged at any desirable point along the line, which
electro-magnet is enclosed in a case o (figure 1) carried on a post or otherwise
suitably supported.
The armature t of the said electro-magnet is connected by the links u with the
shaft i, to which a hand or index k is so attached as to be visible from the line.

page_text: In Figures 1 and 2 the box o,. is shown in a horizontal position but it is
arranged vertically when in use, in order that it can be observed by train officials.
One end of the coils of the electromagnet is in connection with the earth.
The face of the case o is formed of two glass plates having a space between them
in which moves the hand k. The rear glass plate is rendered opaque by grinding
or otherwise whilst that in front is transparent, in order that a lamp placed in the
box during the night will enable the position of the hand to be seen.
The binding screw c (Figure 1) is connected by the conducting-wire with a
small galvanometer m placed at the station or signal box, which galvanometer is
in the circuit of the galvanic battery n.
The sides of the cylinder 6 must be well insulated from the piston-rod e, and
both cylinders must be insulated from.the semaphore post.
The above described apparatus operates in the following manner, that is to
say when the semaphore is placed at "Line clear" by moving the lever arm p,
serving for adjusting the semaphore to the position shewn in Figure 1, the said
lever arm will move the piston & and the rod e inwards. The said lever arm is
held in contact with the disc f by a spring arranged below the said arm and
engaging with teeth formed in the guide-bar r. When the piston-rod is pushed
inwards, its inner end comes into electrical contact with the screw c of the
cylinder b thereby completing the circuit between the battery n and the coils of
the electromagnets in the box o, which causes a deflection of the galvanometer m
at the station, and also of the hand k. When the lever arm p is moved to the
position shewn in Figure 2 so that the semaphore is placed at "Stop" the pressure
of the said lever arm against the disc f ceases, so that the rod e is pushed outwards
by the spring, and the contact with the binding screw c is broken, whereby the
current passing through the galvanometer m; the conductor l, the piston-rod e, the
screw g the conductor h and the electro-magnets to the earth is interrupted. The
hand and also the galvanometer m then assume their normal positions.
The apparatus hereinbefore described can also serve for calling back a train
after it has left a station, if it has not passed the box o. This is effected by
alternately opening and closing the electric circuit between the battery n and the
electromagnet 8; whereby the hand k is caused to oscillate, which oscillating
motion can be seen by the officials of a passing train.
Having now particularly described and ascertained the nature, of the said
invention and in what manner the same is to be performed, I declare that what
I claim is
The apparatus herein described for indicating the position of the arms of
semaphore signals, the said apparatus comprising a piston d which, when the
semaphore is in the position showing "Line clear," is held back by the lever-arm p
of the semaphore, thereby closing an electric circuit and causing the deflection of
a galvanometer m at the station, and the energizing of an electromagnet s placed
at any desirable point upon the line of railway, the armature t of the said electro-
magnet being connected with a hand k, which is visible from the line and causing
it to be deflected; whilst when the semaphore is placed at "stop," by moving the
lever arm p, the said piston is moved outward by the spring a thereby breaking
the electric circuit and causing the galvanometer and the hand k to return to their
normal positions.
HASELTINE, LAKE & Co.,
For the Applicant.