IMPROVE- MENTS IN APPARATUS FOR COMPENSATING THE EXPANSION AND CONTRACTION OF RAILWAY AND OTHER SIGNAL WIRES
Year: 1878

page_text: LETTERS PATENT to George Schofield, of Railway Foundry, Elland, in the
County of York, Engineer and Ironfounder, for the Invention of "IMPROVE-
MENTS IN APPARATUS FOR COMPENSATING THE EXPANSION AND CONTRACTION
OF RAILWAY AND OTHER SIGNAL WIRES."
Sealed the 4th March 1879, and dated the 7th September 1878.
PROVISIONAL SPECIFICATION filed by the said George Schofield at the
Office of the Commissioners of Patents on the 7th September 1878.
GEORGE SCHOFIELD, of Railway Foundry, Elland, in the County of York,
Engineer and Ironfounder. "IMPROVEMENTS IN APPARATUS FOR COMPENSATING
THE EXPANSION AND CONTRACTION OF RAILWAY AND OTHER SIGNAL WIRES."
The object of this Invention is to compensate for the expansion and contraction
of signal wires caused by the variation of temperature to which they are subjected,
and to ensure the proper and efficient working of the signals irrespectively of
atmospheric changes however great, whether they be for railways, inines, or for fog
signals, or any others in which wire is used as an agent or auxiliary for operating the
same.
And my improvements consist in the application of slide pieces which have teeth
or notches of a suitable kind cut or cast in them somewhat in the form of a "rack,"
and studs or pins are fixed at suitable places in the same, and these are made to
slide in a frame or standard, in the sides of which are made slots of such form and
length as to cause the before-mentioned slides to intersect or take into each other
immediately upon the operating of the connecting lever, which I propose should be
the signalman's ordinary lever, which I attach by a rod and suitable means to one
of the before-named slides, and so obtain direct action. To the other slide is
attached the signal wire, which is secured by suitable means to one or both ends of
the same, one end of the wire passing over a pulley fixed in suitable bearings to
Duine C21

page_text: the top of the standard or frame. A weight or weights is attached to the end of
the wire so fastened (or I may use a chain or any other suitable article or material,
attaching it to the slide, and passing it over the pulley and weight it, as in the case
of the wire), and the wire which is attached to the other or opposite end of the
slide passes over or under one or more pullies to the signal. Now this latter slide,
when not otherwise operated by the other slide intersecting or taking into it, is
moved up or down by the action of the atmosphere on the wire, its distance being
regulated by the intensity of the same; but whether the slide remains stationary
or is moved up or down (that is to say, whether the action of the atmosphere has
caused the wire to expand, which would have the effect of moving the slide upwards,
or to contract, which would move it downwards), immediately upon the operating
of the signal lever, as aforesaid, the other slide takes into the teeth of the slide
operated by the atmosphere, and so raises or lowers it, and places the signal arm or
other device just as required, as though no, atmospheric change had taken place.
In some cases, where very long distances exist between the cabin and signal,
it may be found advantageous to place counterbalance weight or weights in the
centre or other convenient part of the wire to assist in bringing back the slide and
wire

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Schofield in' the Great Seal Patent Office. on the 6th March
1879.
GEORGE SCHOFIELD, of Railway Foundry, Elland, in the County of York, En-
gineer and Ironfounder.. "IMPROVEMENTS IN APPARATUS FOR COMPENSATING THE
EXPANSION AND CONTRACTION OF RAILWAY AND OTHER SIGNAL WIRES."
The object of this Invention is to compensate for the expansion and contraction
of signal wires caused by the variation of temperature to which they are subjected,
and to ensure the proper and efficient working of the signals; irrespectively of
atmospheric changes however great, whether they be for railways, mines, or for fog
signals, or any others in which wire is used as an agent or auxiliary for operating the
same.
And in order that my Invention may be more clearly understood, I have here-
unto annexed one Sheet of Drawings illustrative of the same as applied to ordinary
signal apparatus, which method, with slight variation according to circumstances,
is applicable to almost all kind of signals..
I have marked the Drawing with figures and letters of reference, the same letter
referring to the corresponding part in the various views or Figures.
Fig. is an elevation shewing arrangement of slide pieces and wire to signal
post; Fig. 2 is section of part of same; Fig. 3 is back elevation; Figs. 4 and 5
are front and side views of slide pieces; and Fig. 6 is ordinary signal postwith arm.
A and B are two slide pieces, which are made of suitable length, according to the
requirements, to meet the contraction and expansion of the wire which operates the
signal. Teeth or notches of suitable form C are cut or formed therein, and these
intersect or take into each other immediately upon the operating of the connecting
lever or rod D, which is connected to the signalman's ordinary lever, and which rod
is attached to the slide piece B, so that immediate and direct action is obtained.
E is the frame or standard, in which are formed openings or slots F and G, the
latter of which are formed slightly out of the perpendicular line at their bottom
ends to allow the slide piece B to be free from contact with the slide piece A when
not operated by the signalman's lever. Hare studs or pins which are fixed in the
slide pieces, and which slide up and down in the slots or guides F and G. To the
slide A is attached the signal wire J, and to the opposite end of the slide is attached
a wire, rope, chain, or other suitable substance, which passes over a pulley K, and a
weight or weights L are attached thereto for counterbalancing. The wire J passes
under a pulley M (or more than one pulley can be employed if required) to the
signal post N.
"
It will be observed that the slide A when not otherwise operated by the
slide B intersecting or taking into it, as described, that it is free to be moved
up and down by the action of the atmosphere on the wire, its distance moved
being regulated by the intensity of the atmosphere, but whether the slide remains
stationary or is moved up or down (that is to say, whether the action of the atmo-
sphere has caused the wire to expand, which would have the effect of moving the
slide A upwards, or to contract, which would move it downwards), immediately
upon the operating of the signalman's lever, as aforesaid, the slide B would be made
to rise, if, as in the view shewn at Fig. 6, the arm O was required to be raised to
danger," as indicated by the dotted lines; or the slide B would be lowered if the
arm was at "danger," as though no atmospheric change had taken place.
The advantage of such simplicity of action over all other known contrivances
will be obvious to those practically acquainted with the working of signal wires,
no detaching of the wire being required, nor the use of any springs, and all setting
up or letting off the wire being entirely avoided, and any length of wire can be
compensated for, and the situation, whether round sharp curves or straight lengths,
being always operated upon by the use of my improved apparatus.

page_text: The apparatus can be so arranged as to be worked horizontally as well as verti-
cally, & placed in any suitable position, either within or without the "cabin," and
may be attached to each lever.
Having thus described the nature of my said Invention, and shewn by Drawings
how the same may be performed and put into practice, I would have it understood
that I do not confine myself to, the precise details of construction as herein shewn
and described, but what I claim as my Invention and believe to be new is, the
application, connecting, and operation of the slide pieces A and B, in manner and
for purposes substantially as sbewn and described.
In witness whereof, I, the said George Schofield, have hereunto set my hand
and seal, this First day of March, in the year of our Lord One thousand
eight hundred and seventy-nine.
Witness,
W. WHITEHEAD,
Engineer & Patent Agent,
Halifax.
GEORGE SCHOFIELD. (L.S.)