CERTAIN IMPROVEMENTS IN CONNECTION WITH RAILWAY AND OTHER LIKE SIGNALS AND ACTUATING LEVERS AND CONNECTIONS"
Year: 1882

page_text: LETTERS PATENT to Samuel Sealy Allin of Woodstock Road Bedford Park
in the County of Middlesex for an Invention of "CERTAIN IMPROVEMENTS
IN CONNECTION WITH RAILWAY AND OTHER LIKE SIGNALS AND
ACTUATING LEVERS AND CONNECTIONS"
THEIR
PROVISIONAL SPECIFICATION left by the said Samuel Sealy Allin at the
Office of the Commissioners of Patents on the 5th January 1882.
SAMUEL SEALY ALLIN of Woodstock Road Bedford Park in the County of
Middlesex "CERTAIN IMPROVEMENTS IN CONNECTION WITH RAILWAY AND
OTHER LIKE SIGNALS AND THEIR ACTUATING LEVERS AND CONNECTIONS"
The Invention relates to the wire or other metallic media, and lever or other
mechanism forming connection between the Signals, and the levers from which
motion is transmitted to such Signals.
The object of this Invention is to removo the difficulty now experienced in
working such Signals in consequence of the expansion and contraction of their
metallic connectious and to maintain the Signals automatically in the same positions
in varying temperatures.
The difficulty at present experienced consequent upon the varying tension of the
said wire connections is caused by the fact that it is necessary in most cases to
have the Signals at a considerable distance from the Signalıman's box with the
result that a very considerable length of wire or rod is exposed to all changes of
temperature and in consequence varies greatly in its length according to the rise
or fall of temperature.
I propose to counteract such variation of length in the said wire or rod leading
to the Signal post, by such an alteration in the proportions of the actuating lever or
its equivalent, and of the lever or its equivalent attached to or near the Signal post
as will make the expansion and contraction of the rod or wire connecting the last
named lever to the Signal itself, to equal or balance such variation; but inasmuch as
it would be practically impossible to give these levers such proportions as would
enable the expansion and contraction of a short rod to equal that of one very many
Price 6d1

page_text: times its length if both were as at present composed of the same material namely
of iron or steel. I make the shorter rod or wire directly attached to the Signal of
material or metal capable of much larger expansion and contraction than that of
iron or steel, as for instance Zinc which metal expands nearly two, and a half times
as much as Iron at similar temperatures, and I attach this zinc rod to the shorter
arm of the lever at the base of the Signal post at such a distance from its fulcrum
that its expansion will exactly. equal or balance that of the longer wire or rod
attached to the other or longer arm of the said lever. In cases where excessive
lengths of wire connections are used which would require the long arm of the said
levers to be of inconvenient proportions I increase the expanding power of the
shorter rod connected with the Signal by increasing its length, that is using several
lengths of rods and connecting them top and bottom in a manner which will make
their combined lengths agree with, and be proportionate to the expanding and con-
tracting quality of the longer length of wire

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Samuel Sealy Allin in the Great Seal Patent Office on the
5th July 1882.
SAMUEL SEALY ALLIN of Nine Elms in the County of Surrey. " CERTAIN
IMPROVEMENTS IN CONNECTION WITH RAILWAY AND OTHER LIKE SIGNALS AND
THEIR ACTUATING LEVERS AND CONNECTIONS"
The Invention relates to the wire or other metallic media and lever or other
mechanism forming connection between the signals and the lovers from which
motion is transmitted to such signals.
The object of this Invention is to remove the difficulty now experienced in
working such signals in consequence of the expansion and contraction of their
metallic connections and to maintain the signals automatically in the same
positions in varying temperatures
The difficulty at present experienced consequent upon the varying tension of the
said wire connections is caused by the fact that it is necessary in most cases to
have the signals at a considerable distance from the signalman's box with the
result that a very considerable length of wire or rod is exposed to all changes of
temperature and in consequence varies greatly in its length according to the rise or
fall of temperaturo
I propose to counteract such variations of length in the said wire or rod leading
to the signal post by such an alteration in the proportions of the actuating lever or
its equivalent, and of the lever or its equivalent attached to or near the signal post
as will make the expansion and contraction of the rod or wire connecting the last
named lever to the signal itself to equal or balance such variation but inasmuch as.
it would be practically impossible to give the levers such proportions as would
enable the expansion and contraction of a short rod to equal that of one very many
times its length if both were as at present composed of the same material videlicet
of Iron or Steel I make the shorter rod or wire directly attached to the signal of
material or metal capable of much larger expansion and contraction than that of
iron or steel as for instance Zinc which metal expands nearly three times as much
as iron at similar temperatures I attach this zine rod or tube to the shorter arm of
the lever at the base of the signal post at such a distance from its fulcrum that its
expansion will exactly equal or balance that of the longer wire or rod attached to
the other or longer arin of the said lever. In cases where excessive lengths of wire
connections are used which would require the long arm of the said lever to be of
inconvenient proportions I increase the expanding power of the shorter rod or tube
connected with the signal by increasing its length that is by using several lengths of
rods and connecting them at top and bottom in such a manner as will make their
combined expansion agree with and be proportionate to the expansion of the
longer length of wire.
In order that the Invention may be well understood and explained I have
hereunto annexed a Sheet of Drawings illustrating as an example the adaptation
of my improvements to an ordinary Railway signalling apparatus.

page_text: In these Figs. a is the lever in the signalman's box actuating the semaphore
arm b pivoted to the signal post c. The connections between the lever a and the
rock lever d at the bottom of the signal post c are made in the usual manner by
the metal wire e but in lieu of the rod forming connection between the bottom
rock lever d and the semaphore arm b being made of iron it is composed of zinc
which is capable of much larger expansion and contraction than the iron or steel
wire e
This rod z I attach to the shorter arm of the rock lever d at the base of
the signal post cat such a distance from its fulcrum that its expansion will
practically equal or balance that of the longer wire e attached to the longer arm of
the lever d.
In cases where excessive lengths of wire connections are used which would
require the long arm of the lever d to be of inconvenient proportions I increase the
expanding power of the shorter rod connected with the signal as shewn at Fig 2.
by increasing its length that is by using several lengths of rods and connecting
them at top and bottom in such a manner as will make their combined expansion
aided by the proportions of the lever agree with and be proportionate to the
expansion of the longer length of wire. In conclusion it will be understood that
although I have as an example shown and described my improvements as adapted
to that class of signal called a semaphore that is a signal whose arm receives a
rising and falling motion the improvements are equally applicable to signals
receiving a rotary or sliding motion if the connections between such signals and the
levers actuating them are composed of metallic wire or rods.
Therefore what I claim as new and as of iny Invention is
Establishing a balance between the expansion of two metallic connections on
each side of the rock lever d (shewn in the Drawings annexed) or its equivalent
First By lengthening the shorter connection when necessary.
Second By making it of a highly expansive metal such as Zinc and
Third By giving the rock lever such proportions as shall cause the high expan-
sion of the shorter connection on one arm practically to balance the low expansion
of the longer connection on the other arm, the expansion of both being taken up
by the rock lever and each thus counteracting the other in the manner as herein
substantially described and shewn in the Drawings annexed
In witness whereof I the said Samuel Scaly Allin have hereunto set my
hand and seal this the first day of July in the year of our Lord One
thousand eight hundred and eighty two.
S. SEALY ALLIN.
(L.S.)