IMPROVEMENTS IN SIGNALS FOR RAILWAYS.
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Everard Richard Calthrop at the.
Office of the Commissioners of Patents on the 11th March 1879.
EVERARD RICHARD CALTHROP, of 15, Water Street, Liverpool, in the County of
Lancaster. " IMPROVEMENTS IN SIGNALS FOR RAILWAYS.".
My Invention has for its. object amongst others the prevention or reduction of
the risks to trains and other moving objects consequent upon the employment of
flagsmen and other hand signalling, for example, in the cases of relaying, break-
downs, fog signalling, repairs to bridges, accidents to existing signals, and all other
cases where temporary signalling is required.
.
My Invention consists of a novel construction of semaphore and light signal post
and apparatus connected therewith, operated upon by an electric current obtained
from a battery or from an electro magnetic generator. The construction is a tripod
frame or stand, the legs of which are of telescopic form and adjustable, and which.
carries and supports a shell or casing which contains the operating mechanism and
a lamp; this mechanism consists of a centre or primary shaft in connection with
a secondary shaft carrying and working a semaphore or its equivalent. The
primary shaft also moves, and works a danger screen or guard in connection with
the lamp. On the primary shaft there is mounted and fixed a horizontal electro
magnet, free to swing as the shaft rotates and acting as a prime mover to the
primary shaft. This horizontal or partially rotating electro magnet receives its
motion from two vertical fixed horseshoe magnets, provided with soft iron pole
pieces, and situated one on either side of the swinging magnet, with their poles
spaced apart to correspond with the arc of swing of the said swinging magnet;
this distance corresponds with the swing required to change the position of the
semaphore or danger screen. The poles of the swinging magnet are operated on
by the pole pieces of the magnets on either side of it. The movement of the sema-
phore arm and the lamp danger screen or shade is accomplished by reversing the
direction of a current of electricity flowing through the coils of the two fixed
vertical horseshoe magnets, and so causing the horizontal electro magnet and the
primary shaft and in consequence the semaphore shaft and danger screen partially
to rotate. The direction of the current of electricity flowing through the coils of
the swinging horizontal electro magnet is not reversed, an arrangement which is
effected by a commutator in connection therewith, consequently the poles of the
swinging horizontal electro magnet remain unchanged.

page_text: A modification may consist in substituting a partially rotating permanent magnet
for the partially rotating swinging electro magnet. In this case the commutator
may be dispensed with.
Another modification may consist of one or more horizontal armatures attached
to the primary shaft, at the ends of which are two or more vertical electro magnets
arranged radially to the primary shaft and fixed to the foundation plate. The
armatures are free to rotate over the poles of the vertical electro magnets. Suppose
four vertical electro magnets A, B, C, and D, arranged radially to the primary shaft
and the armature standing over A by a suitable automatic commutator a current
of electricity passes successively through the helices of A, B, C, and D, and the
armature is attracted successively by each. Supposing the armature to stand
over A and a current of electricity to be sent through the line wire, the armature
will first be attracted by B, and having arrived over B the commutator will break
the circuit through B and open it through C. The armature will then be attracted
to C, and so on, until the armature stands over D. To move the armature in the
opposite direction from D to A the circuit is reversed, upon which the commutator
closes the circuit through D and opens it through C.
A further modification may be worked by pneumatic pressure controlled by
electricity, and consists of a tripod stand, as already described, on which is fixed a
hollow chamber or receiver in which to store compressed air. At the base of the
air chamber is fixed a condensing air pump worked through suitably contrived
shafting by the depression of a stud or lever on the railway line, so arranged that
the wheels of a train passing over it shall depress it through a certain distance,
after the passage of a wheel a resisting spring restores the lever or stud to its
original position; or the air may be compressed into the receiver by means of an
air pump worked by hand. A safety valve is also fixed to the air chamber to
prevent the internal pressure from exceeding a certain limit. Or the motive power
may be produced by hydraulic pressure, in which case an accumulation overflow
reservoir and force pump are substituted for the air chamber and air pump. The
driving mechanism consists of a cylinder and piston acted on by the fluid under
pressure controlled by a valve. The end of the piston rod is connected directly or
through a system of levers, or other suitably devised mechanism, with the sema-
phore arm and red glass shade. The valve rod is connected directly or through a
system of levers or other suitably devised mechanism to the armature of one or
more electro magnets, which is withheld from the poles of the electro magnets by
a resisting spring. The semaphore arm is so constructed that it moves to the
position indicating danger by its own weight or by the weight of a counter balance.
When a current of electricity passes through the helices of the electro magnets the
armature is attracted, the port opened, and compressed air or liquid admitted to the
cylinder, and the semaphore is brought to the position "all right."
When the current ceases the armature is released from the electro magnets by
the resisting spring. The compressed air or liquid is allowed to escape by the
valve through the exhaust port, and the signal returns by its own weight to
danger."
"
The signals can be so arranged that a train passing from section A, B, to section
B, C, will automatically take off the signals at block A and put on the signals at
block B.
Another modification of the portable signal may be worked mechanically by a
combination of levers, pulleys, and other suitably arranged mechanism, operated by
a suspended wire kept constantly in tension by a weight or counterbalance situated
on the tripod stand, as previously described.
A locking apparatus, which may be attached to all portable signals worked or
controlled by electricity, consists of two permanent magnets, so pivoted and
arranged that the north poles of each of them shall alternately fall on the pole
pieces of each of the outer of a pair or series of electro magnets. The poles of the
outer electro magnets of a pair or series must be of opposite polarity, so that on
the reversal of a current of electricity flowing through the helices of the electro

page_text: magnets, the one permanent magnet is repelled and the other attracted. Fixed to
the permanent magnets and moving with them is a frame, carrying a bar, passing
through a spherical weight which is free to slide along the bar. On this frame is
fixed a tooth or other projection corresponding with a tooth or cavity on the
primary shaft, so arranged that the tooth on the frame of the permanent magnets
locks the tooth on the primary shaft as soon as the primary shaft completes its arc
of travel, preventing the primary shaft from moving. On the current being
reversed the permanent magnets change their position and the tooth of the primary
shaft is released. This electric locking apparatus may be applied to permanent
signals and many other purposes.
Portable signalling apparatus constructed according to my Invention can be put
up and be worked shortly after the alarm has been given, and can be used as a
temporary signal for emergency. It can also be used as an automatic repeater for
the present permanent signals, and, if necessary, can be made to ring a bell when at
danger, or it can be placed in such a position on the line and as sufficiently near
the engine driver as necessary.