IMPROVEMENTS IN APPARATUS FOR COUNTERACTING OR COMPENSATING THE EFFECT OF VARIATIONS OF TEMPERATURE ON RAILWAY SIGNAL PULLS
Year: 1884

page_text: I, WALTER KING of Houston in the County of Renfrew, Gentleman, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN APPARATUS FOR
COUNTERACTING OR COMPENSATING THE EFFECT OF VARIATIONS OF TEMPERATURE
ON RAILWAY SIGNAL PULLS," to be as follows:-
This Invention has for its object to ensure that the length of the pull, that is, to
say, of the wire or chain between the semaphore or signal arm, and the signalman's
lever by which the signal is operated, shall be allowed to expand and contract
under variations of temperature and be at the same time always kept "taut" or
stented so that the semaphore and the signalman's lever are practically always in
the same position relatively with each other.
The apparatus constituting the Invention consists as shewn on the accompanying
drawing, of a lever frame or beam A, composed of two side frames with a space
between them, which lever is centred on a beam B, close to and parallel with the
usual beam C, bearing the signalman's hand lever D. One end of the lever
frame A projects over the beam C, so that the said beam serves as a rest or stop
for it.
In the lever frame A, two other levers E, F, are centred, the lever E being
connected to the hand lever D, by a link G; and a spring H also attached to the
lever frame, bears against the under side of the lever E, and maintains the lever or
frame A in proper position relatively with other parts of the mechanism. Two
pulleys or drums I l' are also carried in the lever frame A, and over these pulleys
or drums, a portion of the signal pull J, (secured at its outer end to the semaphore
weight or lever in the usual manner) is passed.
The portion of the pull J, so passing over the pulleys I, 1', is preferably made of
leather, canvas, or other belting, as flexible but as inelastic and incompressible as
can be got; and at the end of the said portion hanging over the pulley I, a counter-
weight is secured which is just sufficiently heavy to keep the signal pull properly
taut or stented throughout its length without acting on the semaphore itself.
When the seinaphore or signal is at danger the apparatus hercin before described
is in the position shewn at figure 2, that is to say, the pull J, is free to move in one
direction in obedience to contraction in its length, or in the other direction in
obedience to the counterweight when expansion or lengthening of the pull takes.
place.

page_text: When it is desired to signal the line clear, the signalman in pulling the hand
lever D closes the lever E, down on the pull J, which is thereby firmly gripped
between the raid lever and the lever F, as seen at figure 1, whereby he is enabled
to at once draw the signal to show the line is clear, that is to say, he has not, as
with the usual apparatus, to first take up any slack on the pull J, before the motion 5
of the hand lever D acts on the signal; the improved apparatus constituting the
Invention always practically maintaining the pull J, of such a length that the
lever D at once acts on the signal.
Dated this th d of
1007
I, WALTER KING of Houston in the County of Renfrew, Gentleman, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN APPARATUS FOR
-COUNTERACTING OR COMPENSATING-THE-EFFECT OF VARIATIONS_OF_TEMPERATURE
_ON. RAILWAY SIGNAL PULLS" and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement:-
My said Invention has for its object to ensure that the pull, that is to say, the
length of wire or chain between the semaphore or signal arm and the signalman's
operating lever shall be allowed to expand and contract under variations of
temperature without affecting the position of the semaphore or signal arm and
shall at the same time always be kept "taut" or stented so that the semaphore
and the signalman's operating lever are practically always in the same or in the
proper position relatively with each other.
On the sheet of drawings hereunto appended Figure 1, is a vertical section;
figure 2, a part side elevation and figure 3, a plan of the improved counteracting
or compensating apparatus, which consists of a lever frame or beam A, composed of
two side plates or cheeks held at the proper distances apart by angle irons B,
inserted between their ends and to which the said side plates are screwed bolted,
or otherwise secured and by one or more intermediate stay bolts.
The frame A, is preferably centred on the shaft or stud C, carrying the signal-
man's lever D, which is encased in a frame E', supported on a cross beam F, as
usual but instead of so centring the frame A, on the same beam as the signalmans
hand lever it may as shown on the drawings annexed to my provisional specification
be centred on a separate beam close to and parallel with the beam carrying the
signal lever.
When the apparatus is in the position illustrated by figure 1, the beam F, acts
as a rest or stop for the frame A, and prevents its end A³, from moving too far
downwards.

page_text: The signalman's lever D, is preferably bell-cranked or has an arm D', formed at
its lower end and in conjunction with the said lever arm another lover G, centred
or pivotted at a, in the frame A, is employed. The lever G, which at its inner end
is prevented from moving too far downwards by the stop or pin o, has at or near
its centre a curved or other shaped projecting part a, opposite which a corresponding
hollow or indentation b, is made on tho under side of the lever arm D'.
At or towards the ends of the frame A, pulleys or drums H¹, H³, are centred by
preference adjustably as shown, and between those pulleys another pulley or drum I,
is also carried in the frame.
The signal pull J, is at its outer ond secured to the end K, of the signal lever K',
(figure 4) in the usual manner and a portion of it passes over the pulleys H³, H³,
and under the pulley I, the part between the pulleys I, and H2, when the signal
arm L, figure 4, is at danger and the rest of the apparatus is in the position shown
at figure 1, passing freely between the under side of the lever arm D', and the
upper surface of the lever G, as illustrated.
The portion of the pull J, passing over and under the pulleys H', H, I, is
preferably made of leather canvas or other belting as flexible but as inelastic and
incompressible as can be got and at that end of the said portion which hangs over
the pulley H, a counterweight M, is secured. The weight M, is just sufficiently
heavy to keep the signal pull J, taut or stented throughout its length without
acting on the lover K³, figure 4, so as to overcome the weight N, and disturb the
position of the semaphore or signal arm L, whilst on the other hand the weight N,
must be sufficiently great, when the pull J, is released by the levers D, G, to draw
the pull sufficiently to allow the somaphore L, to go "home" to the danger position.
The counterbalances M, and N, must therefore each be regulated in weight according
to the distance of the signal post O, from the signalman's operating hand lover D,
as it is manifest that weights which will act efficiently at short distances and with
a short length of pull J, will require to be increased as the distance and length of
pull J, increases.
With the lever framo A, and lever K¹, of or about the dimensions shown and
with the pulleys H1, H2, at or about the position in the frame A, indicated on the
drawings and the weight N, at or about the position shown on the lever K¹, I have
found a weight of 106 pounds at M, and a weight of 53 pounds at N, to act
satisfactorily with a pull of 350 yards. As the distance increases besides increasing
the weights M, N, the leverage Č, H³, C, H³, must also manifestly be lengthened to
maintain the efficiency of the apparatus and in some cases instead of putting all
the stenting weight at M, part of it only may be so situated and the remainder
placed at a point intermediate between the end A¹, of the frame and the weight N.
As hereinbefore stated when the semaphore or signal arm L, is at danger the
apparatus constituting the Invention is in the position shown at figure 1, that is to
say, the pull J, is free to move in ono direction in obedience to contraction in its
length (in which case it raises the weight M) or in the other direction in obedience
to the counterweight M, (when expansion or lengthening of the pull takes place)
the pull being thus in all cases kept taut or stented by the weight M.
When it is desired to signal the line clear the signalman in pulling the hand
lever D, closes the lever arin D', down on the pull J, which is thereby firmly and
effectually gripped between the said arm and the lever G, as scen at figure 2, the
curved projection a, on the lever G, and the hollow or indentation b, on the arm D¹,
assisting to prevent slipping The signalman is thereby at once and always enabled
to draw the signal to show the line is clear, that is to say, he has not as with the
usual apparatus to take up any slack on the pull J, or lengthen the pull J, before
the motion of the hand lever D, acts properly on the signal, the improved apparatus
as before explained, always practically maintaining the pull J, of such a length
that the motion or stroke of the lever D, is at once and uniformly operative on
the signal arm or semaphore.
Although it is preferred to construct the signalman's lever with a lever arm D',
as heroinbefore explained and shown on the drawings annexed to this my complete

page_text: Specification it is to be understood that as an alternative, the arrangement illustrated
on the drawings annexed to my provisional specification may be adopted, that is
to say, instead of constructing the lever D¹, integral with the lever D, a separate
lever may be used connected to the lever D, by a link as at E, G, of the said
provisional drawings.
With either arrangement a spring H, is or may be used to maintain the frame A,
in proper position relatively with the lever E, or lever arm D¹.
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,
First In combination with railway signal pulls the apparatus consisting of the
lever frame A, pulleys or drums H₁, H, I, lever G, weight M, lever arm D¹, on the
signalman's lever D, and spring H, substantially as and for the purpose set forth
and illustrated on the drawings annexed hereto.
Second-In combination with railway signal pulls the apparatus consisting of
the lever frame A, levérs E, F, link G, and pulleys I, 1', substantially as and for the
purpose set forth and illustrated on the drawings annexed to my provisional
specification.