Improvements in Interlocking Railway Points and Signals.
Year: 1899

page_text: Date of Application, 7th Mar., 1899- Accepted, 8th Apr.,
1899
COMPLETE SPECIFICATION.
Improvements in Interlocking Railway Points and Signals.
I, CHARLES PRATT, of Ajmere, Rajputana, Hindoostan, Executive Engineer,
P. W. Department, Rajputana-Malwa Railway, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:―
My invention relates more particularly to those railway point and signal
installations where the points are at such a distance from the signal lever box
that the points cannot be worked directly from such box. In such cases it has
not been possible heretofore to provide for the complete interlocking of the points
and signals under the control of the station master, except by the use of "keys,"
which are open to serious objections..
My invention has for its object to provide for a complete system of point and
signal interlocking in such cases without the use of keys and it consists in pro-
viding, at the place where the point and point lock lever frame is situated, an
interlocking apparatus or tappet box through which pass rods or bars from the
point and point locking levers and also rods or bars which are connected at one
end to the wire signal pulls coming from the signal levers at a distance and at
the other end to the signal rodding, such rods being moved in one direction by
the lever pulls and in the opposite direction by the signal counter weights.
I will describe my said invention with reference to the accompanying draw-
ings, in which Figure 1 shews a plan of the points, point and pointlocking levers,
tappet box and signals; Figure 2 shews a sectional side elevation of the points
lever frame tappet box, and signals post and rodding on line Figure 1 and
Figure 3 shews an enlarged plan of the tappet box with the cover plate removed.
A is a lever frame holding the levers H, K, L, M of any group of points CD
and point locks CD which it is required to interlock with any of the signals
on the signal post, whose rods are marked E F G respectively,
A tappet box B is fixed either on the ground as shewn or to any portion of the
lever frame. Through this tappet box run the rods or bars 1, 2, 3, 4, from each
of the point and point lock levers, also the rods or bars 5, 6, 7 from the rods
E, F, G of each of the signals required to be interlocked the connection between
the tappet box and the signal levers at the station cabin being by wire
pulls 8, 9, 10. The interlocking is effected by the rods or bars running through
the tappet box, these rods being actuated, in the case of the point and point
lock rods, by the levers in the lever frame A, and in the case of the rods or bars
from the signal arms these are actuated in one direction by the wire pulls 8, 9,
10, pulled from the station cabin which may be say 1,000 feet away, and in the
other direction by the counterweights 11, 12, 13, on the rodding E, F, G, of the
signal arms.
The construction and mode of operation of the tappet box B may be of any
suitable known kind whereby the above described interlocking of the points
and signals can be effected and it need therefore not be farther described.

page_text: All signals are lowered directly from the station, and so no extra control
levers are necessary.
At any station where the signals are not too numerous to be worked by one
signal man, this apparatus would save extra cabins, control levers and signal men.
It will be seen that this arrangement enables the station master at the station
cabin which may be more than 1000 feet distant from the points and signals
to lock directly any set of points or point locks connected by rodding with the
tappet box.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what I
claim is:
In railway point and signal installations wherein the point and point locking
levers are arranged in proximity to the points and signals, while the signal
levers are at some distance therefrom, arranging an interlocking apparatus or
tappet box at or near the point lever frame and signal post through which
apparatus pass the rods or bars from the point and point locking levers,, as also
rods or bars connected at one end to the signal rods and at the other end to the
pulls from the signal levers, so that an interlocking of the points and signals
is effected on the one hand by the movement of the signal rods or bars by the
signal pulls in conjunction with the signal counterweights and on the other
hand by the movement of the rods or bars connected to the point and point lock
levers, substantially as described.
Dated this 7th day of Vero 1899