IMPROVEMENTS IN RAILWAY ELECTRICAL SIGNALLING
Year: 1884

page_text: I, JOHN WILLIAM FLETCHER, Telegraph Engineer, and Superintendent of the
London and North Western Railway Company, of 93, Chatham Street, Edgeley,
Stockport, in the County of Cheshire, do hereby declare the nature of my
invention for IMPROVEMENTS IN RAILWAY ELECTRICAL SIGNALLING to be as
follows:-
My invention consists of an improvement in the arrangement and apparatus at
present employed in Electrical signalling specially applicable to railway work,
whereby only a single wire is used between the signal and the signal box for
indicating the position of the signal, and also the state of the signal light at night.
For this purpose I employ an improved form of contact maker, consisting of a
pole changer or other modification thereof in connection with the signal arm,
together with an improved system of contacts for indicating in the signal cabin
the state of the light at night. The contact maker as at present made by me
consists of four springs or their equivalent, actuated by a cam or eccentric;
together with four springs two of them being to the earth, and the remaining two
to the poles of a battery. The semaphore representing the signal arm, is worked
by a needle coil, and an indicator shewing "light in" or "light out" is worked by
an electro magnet.
In addition to accomplishing the whole of this with a single line wire, I am
enabled by my invention to materially economise the battery power at present
required, by employing virtually only one battery for the whole of the work.
1004

page_text: Improvements in Railway Electrical Signalling Apparatus.
I, JOHN WILLIAM FLETCHER, Telegraph Engineer and Superintendent of the
London and North Western Railway Coy, of 93; Chatham Street Edgley, Stockport
in the County of Cheshire, do hereby declare the nature of my invention for
"IMPROVEMENTS IN RAILWAY ELECTRICAL SIGNALLING APPARATUS and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :—
"
My invention consists of an improvement in the arrangement and apparatus at
present employed in Electrical signalling specially applicable to railway. work,
whereby only a single wire is used between the signal and the signal box for
indicating the position of the signal and also the state of the signal light at night.
For this purpose I employ an improved form of contact maker, consisting of a
pole changer or other modification thereof in connection with the signal arm
together with an improved system of contacts for indicating in the signal cabin,
the state of the light at night. The contact maker as at present made by me
consists of four springs or their equivalent, actuated by a cam or eccentric, together
with four springs, two of them being to the earth and the remaining two to the
poles of a battery. The semaphore representing the signal arm is worked by a
needle coil, and an indicator shewing "light in" or "light out" is worked by an
electro magnet.
"
In addition to accomplishing the whole of this with a single line wire, I am
enabled by my invention to materially economise the battery power at present
required, by employing virtually only one battery for the whole of the work.
In order to explain my invention more in detail I have appended two sheets of
drawings, in which Fig. 1. represents a front elevation of the repeater and light
indicator; Fig. 2 being the buck elevation, Fig. the side and Fig. 4 a plan of
the same.
In Fig. 1. will be seen two distinct sets of coils marked A and B; the coils A
controlling the arm E for repeating the signals, are constructed of fine wire
connected in series in the usual manner for working the induced needle as is found
in most single needle instruments; while coil or coils B are of thicker, wire and
are connected in circuit by wires W, with the coils A, An armature C, is con-
trolled by coils B, and by its movement towards the coils, actuates a small flag D,
or other indicator by means of a prolongation as shewn at C¹, Instead of making
this difference in the size of the wire the same end may be accomplished by fixing
an adjustable spring to the armature C, by which only the full battery can be
caused to operate this armature but in practise I find the foregoing method to be
most reliable.
Fig. 5 is a side elevation of the expansion tube T, and contacts. Fig. 6 being an
end view and Fig. 7 a plan of the same. By the expansion of the brass tube T the
lever A moves on the centre C, thus causing the springs S¹, and S², to be either on
the piece of brass A¹, or on the pieces of ivory I, and I, while springs S³, and S4,
on the opposite side are always on the brass A' The springs S¹, and S³, are
mounted on two separate contacts while S³, and S4, are on the same contact,

page_text: Fig. 8 shews the contact box in which the cock L, carries the contact pins J, J, to
which the line wire W, is connected; the two outer springs P, P, and the cock K
are the earth connections, while the springs C, and D, and cocks C, and D¹, are the
battery connections, The projections R, and R', on the axle Q, moved by lever Z,
cause the springs C, and D, to be placed alternately in connection with the outer.
springs P, P, or the contacts J, J.
In Fig. 1 the small flag F, indicates when the signal is mechanically out of order,
and Fig. 9 (sheet 2) is a diagramatic view of the connections, contact box C,
expansions contacts and repeater E together with the battery; the contact box,
expansion tube contacts, and battery being at the signal post.
Having detailed the various parts of my apparatus, I will proceed to describe
the action of the same. The current from the battery B, (Fig. 9) passes through
the spring S, and metallic lever A by means of springs S³, and S', to the contact
box C, and is commutated to either line or earth H. By the line W', the current
reaches the repeater and light indicator and passes through both coils A, and B
described in connection with Fig. 1. but as the current is only strong enough to
actuate the arm E, Fig. 1. the armature C, is not attracted by reason of which the
small flag D is not raised.
One pole of the battery is connected to the cock D', and spring D.
A further addition to the apparatus is the application of the arm Z, and
contact box C, so arranged, that when the signal is neither on nor off, but midway,
the respective parts in the contact box stand in the position shewn by the diagram;
so that no current passes, and the repeater arm E, assumes the position of the
signal as shewn by Fig. 1, and further exhibits a small flag F, to indicate that the
signal requires mechanical adjustment.
The foregoing description applies to the signal repeater, I will now proceed to
describe the.working of the light indicator and signal combined when the light is
burning.
The battery B, being divided into two sections, the current passes now from the
battery to the spring S', which is brought into contact with the brass A¹ which is
caused to move by the tube T, expanding, thus causing spring S¹, to rest on the
ivory I, at the same time that S, is on the ivory I, and by further expansion of
the said tube, S³, makes contact with the brass A', by which means the current of
the whole battery is used, raising both the arm E, and flag D, and thus indicating
that the signal is up or down according to the direction of the current and that
the light is in.
On the light going out the reverse action takes place.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
The working of signal and light repeaters by which three positions are shewn
only one wire being used.
The form of contact box substantially as described and illustrated.
The arrangement of the expansion tube contacts substantially as shewn and
described.
WAUGH & CHAPMAN,
70, Chancery Lane, W.C.