IMPROVEMENTS IN ELECTRIC BLOCK SIGNALLING INSTRUMENTS
Year: 1884

page_text: "
I WILLIAM EDWARD LANGDON of 5 Grove Terrace, Derby in the County of
Derby, Superintendent of the Midland Railway Company's Telegraph Department
Derby do hereby declare the nature of said Invention for "IMPROVEMENTS IN
ELECTRIC BLOCK SIGNALLING INSTRUMENTS" to be as follows:-
The object of this Invention is to provide a more ready and more easily operated
and secure means for pegging over or fixing in any required position, the electric
commutator handle or tapper by which the fixed signals such as the "line blocked"
or "line clear" signals are produced.
To this end I provide in the place of the pin employed for pegging the handle
over as at present a small key or thumb piece which I fix in the neighbourhood
of the handle either on one side of the same, immediately over it, or in other
convenient position, a small key having two or more positions one a position of
rest, the other a locking position; or two positions for locking one to lock to the
'blocked" side, the other to lock to the "clear" side or position. This key I form
of such a shape that a part or extended portion shall, when the key is depressed in
a certain position, engage with a fixed part of the instrument handle or coinmutator
or with a piece fixed thereon when the said instrument handle is held in the
required position for affording the permanent signal. To release the key from this
position it is merely necessary to raise it or press it in the opposite direction, that
is, into its position of rest.
"
Now in illustration hereof let it be assumed that the block instrument to which
the improvement is applied is that known as the single needle instrument. This
form of instrument is usually worked by means of a vertical handle. To give the
"block" signal the handle has to be fixed over to one side and to give the "clear
signal it has to be fixed in the opposite position. Whereas then as under the
existing system it is necessary for the signalman to hold the handle over in the
required direction by one hand and to thrust the peg into its position so as to hold
it there by the other hand, it is merely necessary by means of this my Invention
for him to press the thumb or finger of the hand holding the handle over upon the
locking key which thereon engages with the required portion of the bandle or its
connections and retains it in the said position. When it is required to release the
handle or to remove the permanent signal the same hand which operates the handle
also by a slight pressure of the locking key in the opposite direction disengages it
and leaves the handle free for movement in any-direction.

page_text: In a like manner where the form of instrument is that worked by a tapper key,
instead of employing the operators second hand to pin the tapper down it is merely
necessary on placing the tapper in its required position to press by the thumb or
finger of the same hand the locking key into its locking position and similarly to
release it when the signal is no longer required.
I WILLIAM EDWARD LANGDON of 5 Grove Terrace, Derby in the County of
Derby, Superintendent of the Midland Railway Company's Telegraph Department
Derby do hereby declare the nature of said Invention for "IMPROVEMENTS IN
ELECTRIC BLOCK SIGNALLING INSTRUMENTS" and in what manner the same is to
be performed to be particularly described and ascertained in and by the following.
statement:
The object of this Invention is to provide a more ready and more easily operated
and secure means for pegging over or fixing in any required position, the electric
commutator handle or tapper by which the fixed signals such as the "line blocked"
or "line clear" signals are produced.
Figure 1 of the accompanying Drawings is a perspective view of a block
signalling instrument constructed according to my Invention to which the said
improvement is more especially applicable, and Figure 2 shows in side elevation
that portion of the instrument to which the improvement applies, Figure 3 is a
longitudinal vertical section, and Figure 4 an end view of same.
or
A is the handle or commutator by the movement of which to the right or left a
corresponding movement of the needle B (Figure 1) is produced either at the home
or distant station. In order to retain this needle B in either the "blocked
"clear" position it is necessary to fix the handle A, in the corresponding position
and to retain it so, so long as such signal is required to be shown. To effect this I
employ a locking bolt and pin so arranged that the former shall when the handle A
is held over to either side on being pushed in engage with the latter and retain it
in that position until the bolt is withdrawn. C is the bolt (the ends of which
where the letter C is placed as represented in the Drawing, is deeper than the
middle portion). This bolt slides in a socket or groove piece D which is fixed upon
a flange piece E by means of which the bolt and its socket piece is fixed to the
bush or socket I of the instrument handle. Fixed to the bolt C is a button or
push piece F by pressing which either inwards or outwards the bolt is moved as is
required. G is a steel pin fixed in the movable portion H of the handle A working
in the bush piece I which has a suitable slot cut in it to afford it the necessary
freedom of movement.
Now let it be assumed that the "line clear" signal is required to be rendered.
The handle A is held over to the right and by a pressure of a finger of the same
hand upon F the bolt C is shot into the locking position. In being thus pushed
forward the thicker portion of the bolt C passes in front of the pin G and holds it
in that position. On it becoming necessary to release the "line clear" signal the
button or push piece F is again pressed but in the opposite direction so as to

page_text: withdraw it, when it again assumes the position represented at Figure 2 and the
handle A is free to be moved in either direction or to resume the vertical position.
On requiring to give the "line blocked" signal the handle A is held over to the
left side and the push piece F is again manipulated in a similar manner.
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 :-
In electric block signalling instruments the ready and improved means of locking
the commutator or signalling handle of such block instruments in the "line clear
or "line blocked" positions by means of a locking bolt, substantially as and in
the manner herein before described and illustrated with reference to the
accompanying Drawings.
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