CHANICAL ARRANGEMENTS FOR RAILWAY SIGNALLING."
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by William Alder How at the Office
of the Commissioners of Patents on the 12th December 1877.
WILLIAM ALDER How, of Redmarley, in the County of Worcester.
MECHANICAL ARRANGEMENTS FOR RAILWAY SIGNALLING."
"IMPROVED
My Invention consists in working railway signals, whether alone or in con-
junction with audible signals to be given on the engine, tender, or guard's van, and
so that chance obstacles may not cause the sounding gear to give such indications,
with provision that variations in temperature will not affect the correct working
of the signals. In order to prevent variations of temperature influencing the
action of the signals, I strain a compensating and actuating wire from the signal
box to the distant signal post by means of counterweights.
Attached to each wire is a sliding bar working in proper guides on sufficient
supports; and to provide further for variations in temperature, on the lower end of
the signal rod I fix a transverse bar or rod, to which are attached suitable cranks
or levers connected with the before-mentioned sliding bars in such manner that on
the said bars being caused to move by temperature the cranks or levers will move
correspondingly along the transverse bar of the signal rod, thus maintaining a true
position for actuating the signal and locking it in either position of "danger" or
clear," when brought to such positions by the action of the signal lever in the
signal box.
And for still further providing for variations in temperature I intend the cranks
or bars to bring the signals into correct position on completing one-third of their
movement, thus leaving one-third on either sido to meet any slight variation
between the compensating and actuating wires. Should either of the wires break
the signal will be locked to "danger;" and if connected with audible indi-
cations, both will assume the "danger" position.
For working audible signals I attach to the sliding bars at the distant sigual post
two other similar wires, same being strained in a similar manner at any required
distance, attached to which may be sliding bars at intervals for the purpose of
warning at given points. On such bars may be fitted a hammer or hammers in
such manner that when pressed down by the action of the actuating bar they will
be in the position of "clear;" but when relieved from pressure they will then rise
077

page_text: to "danger." Such hammer or hammers may be attached to any other mode of
raising obstacles on the line for giving audible indications.
In conjunction with the before-mentioned hammers I provide fittings on the
engine, tender, or guard's van, in such manner that chance obstructions are pre-
vented from giving the proper indications of danger. I place guards, protectors, or
sounding bars or rods of wood or metal, preferably in a horizontal position, on a
line with, or a little lower than the fire-box or foot plates of the engine, and on
such bars or rods I arrange obstacles, such as cross bars, cogs, or notches, but pre-
ferably the former, on which may rest hainmers or triggers connected with the
whistle, a bell, or other sounding appliance, so that on the passage of the train
over the raised hammers on the lino they will be pressed down by each succeeding
bar, but will on being relieved from pressure instantly cause a stroke or sufficient
blow to be given between each bar to the hammers or triggois resting thereon, and
cause the necessary indications to be given. In addition to any other series of sounds
the knockings caused by the hammers will give (by proper arrangements) clear
indications of danger, which may be found sufficient without a bell or other
sounder. And further, for giving audible indications at will, in conjunction with
the visible signals, it will be only necessary to cause the lever of the signal in the box
to give an extra movement, as is now frequently done, thereby giving the audible
indication immediately after the "clear" position, and without any further move-
ment, thus having a separate visible "danger," and a combined visible and audible
danger."