IMPROVEMENTS IN APPARATUS FOR COMPENSATING THE EXPANSION AND CONTRACTION OF RAILWAY AND OTHER DISTANCE SIGNAL WIDES
Year: 1877

page_text: LETTERS PATENT to Charles Brett, of Deptford, in the County of Kent,
for the Invention of "IMPROVEMENTS IN APPARATUS FOR COMPENSATING
THE EXPANSION AND CONTRACTION OF RAILWAY AND OTHER DISTANCE SIGNAL
WIDES"
Sealed the 9th November 1877, and dated the 26th May_1877.
PROVISIONAL SPECIFICATION left by the said Charles Brett at the Office
of the Commissioners of Patents on the 20th May 1877.
CHARLES BRETT, of Deptford, in the County of Kent. "IMPROVEMENTS IN
APPARATUS FOR COMPENSATING THE EXPANSION AND CONTRACTION OF RAILWAY
AND OTHER DISTANCE SIGNAL WIRES."
The object of this Invention is to compensate for the expansion and contraction
of distance signal wires caused by the variations of temperature to which they are
exposed, thus ensuring the proper and efficient working of the signals irrespective of
atmospheric changes. For this purpose I employ a compensating wire and an
automatically variable compensating weight, all as herein-after described.
The compensating wire I carry along by the signal wire for part of its length, and
so as to be exposed to the same atmospheric influences, and I bring it back to the
station box over pulleys, and I there suspend a tightening weight at one end thereof;
the other end I connect to a box or vessel containing fluid, by preference closed
above. This box is made to rise and fall; this may conveniently be done by sliding
loosely on a pipe above it and another pipe below it, the former pipe being connected
to a fluid supply cistern, and the latter pipe being connected to a fluid waste cistern.
This box forms the automatically varying compensating weight aforesaid.
The supply pipe and the waste pipe are cach provided with a cock, or slide, or
other valve.
The tightening weight on the one end of the compensating wire works between
the two prongs of a forked-balanced lever, raising the latter when a certain amount
of contraction. takes place in the compensating wire (and, of course; also simulta-
neously in the distance signal wire), and lowering it when a certain amount of

page_text: expansion takes place in the wire. In the latter case the aforesaid fork lever, by
means of rod and lever connection, causes a loose sliding bar to operate other lever
und rod connections, which open the cock or valve on the fluid supply pipe, thereby
allowing a certain amount of fluid to run from the supply cistern into the sliding
box, to which the home end of the distance signal wire is connected, by preference
by lever appliances, but in such a way that the descent of the box, because of its
increased weight, pulls up the slack of the signal wire and also of the compensating
wire which is connected thereto, as already stated.
The weight of the empty box and parts connected therewith may be counter-
balanced if desired. The distance signal wire passes round a pulley connected to a
detent or stop wheel, which is held fixed in position by a detent tooth (or it might
be a break) and spring; the tooth is withdrawn automatically by the same gear
which operates the valves or cocks. The valves are cach returned to the closed
position by spring or weight, and act quite independently of each other. The usual
signal lever with weighted tail, and with pulleys at the head end, I fit with loose
pulley on the fulcrum pin and pass the wire thereover. This lever may also be
used for, working a pump which carries the fluid from the waste cistern back
to the supply cistern. The fluid may be water, mixed with glycerine, to prevent
freezing.
In order to give facility for independent adjustment of the wires, independent
levers may be fitted for letting water into or out of the sliding box. This may also
be found convenient for checking or stopping the operation of the compensating
apparatus at any time, or while operating the signal lever.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Brett in the Great Seal Patent Office on the 26th November
1877.
CHARLES BRETT, of Deptford, in the County of Kent.
"IMPROVEMENTS IN
APPARATUS FOR COMPENSATING THE EXPANSION AND CONTRACTION OF RAILWAY
AND OTHER DISTANCE SIGNAL WIRES."
The object of this Invention is to compensate for the expansion and contraction
of distance signal wires caused by variations of temperature to which they are
exposed, thus ensuring the proper and efficient working of the signals irrespective
of atmospheric changes. For this purpose I employ an automatically variable com-
pensating weight in connection with other gear, all as herein-after described.
A, Figure 1, is a compensating wire, which is carried along by the signal wire C
for
part
of its length, and so as to be exposed to the same atmospheric influences;
a, a, are guide pulleys over which the wire A passes; D is a tightening weight,
suspended from one end thereof, the other end being connected to a box or vessel B
containing fluid, and, by preference, closed above. This box is made to rise and fall,
which may conveniently be done by sliding loosely upon a pipe b above it, and
another pipe below it, working in a socket, the former pipe b being connected
to a fluid supply cistern E (or a service pipe), and the latter pipe 6¹ being connected
with a waste cistern F (or a drain). This box forms an automatically varying
compensating weight..
The supply pipe b and the waste pipe b₁ are each provided with a cock or valve ç
and c¹ respectively.

page_text: The tightening weight D has a slot through the middle, a lever & passing clear
through it. The lever & may bo balanced in order to keep it in its middle position,
when a certain amount of contraction takes place in the distance signal wire C (and, of
course, also in the compensating wire A) the weight D rises, thereby raising one
end of the lever d, and lowering the opposite end, which is connected to a loose
sliding bar e, the bottom end of which strikes against the bell-crank lever X, which
by a rod Y is connected to a lever y turning on a fulcrum y, and fitted with a
socket wherein the rod y can slide; this latter is connected to a lever y, actuating
a cock or valve c¹ on or in the fluid waste pipe b', opening the same so that fluid.
can run out of the box B; the latter will then rise and cause the signal wire C to be
slackened. On the other hand, if the signal wire C (and of course, also the com-
pensating wire A), is expanded in length by sensible elevation of temperature, the
weight D will descend, the opposite end of the lever d will rise, lifting also the bar e,
the upper end of which operating against the bell-crank leverf will, through tho
intervention of the rod f¹ and lever ft open the supply valve c, thereby allowing.
water to run into the box B, which when heavy enough will descend and tighten
the signal wire attached to the top thereof, the connection between signal wire C
and box B being in the case here shewn by a lever or beam G, to the other end of
which the home end of the signal wire is attached, passing thence round a detent or
stop wheel H, which is shewn separately in side view at Figure 1, and in end view
at Figure 1b. H' is a guard thereon for holding the chain end of the signal wire in
case of breakage; the detent wheel H has one or two flanges formed with notches,
and can be fixed or locked in position by means of a detent tooth on the end of the:
bar K (or it might be by a brake). K is a spring which serves to hold the detent
bar K in the raised or locking position. At the same time that the waste valve c¹.
is opened the lowering of the bar e will lower the detent bar K, a projection / on.
the latter coming in contact with a projecting noso e¹ on the bar e, the chain end of
the signal wire Č is then free to run out or slacken. On the other hand, when the
bar e is raised and opens the supply valve c, the projection e¹¹ on the bar e will, by
the intervention of the lever k¹ and projection A on the detent bar K, lower the
latter free of the notch in the detent wheel, unlocking the latter, and allowing the
signal wire to take up the slack. The chain end of the signal wire passes round the
middle part of the detent wheel, see Figures 14 and 1b, and the two side flanges are
formed with notches for the teeth of the detent bar K to fall into. The valves c and c¹
are closed by springs g and gl, and act quite independent of each other, and may also
by separate gear be worked independently of the gear for locking the detent H.
Lis the usual signal lever, with weighted tail l, and with pulleys h, h', at the head
end; is a loose pulley on the fulcrum pin; the wire C passes thereover. This
lever, or any other suitable lever frequently used in the signal box, may be used for.
working a pump which carries the fluid from the waste cistern F back to the supply.
cistern E. The fluid may be mixed with glycerine to prevent freezing.
In order to give facility for independent adjustment of the wires, independent.
lever gear is preferably fitted for letting water into or out of the sliding box. This
facility for checking or stopping the operation of the compensating apparatus is
available at any time, as required, if the expansion or contraction of the signal wire.
should not be so great as to sensibly influence the compensating wire and causing.
the weight D to be readily raised or lowered. P is a lever, here for the sake of
convenience mounted loosely on the signal lever fulcrum spindle or pin. It is by.
and lever connected to a bar D₁, having two lugs d, d, which as the lever P
is moved one way or the other come in contact with the lever d, thereby unlocking
the detent and opening the supply valve c or the waste valve c¹.
rod
Figure 2 of the accompanying Drawings represents a modified compensating.
arrangement for a distance signal wire according to this Invention. C is the wire
to the distance signal A; B is the sliding box to which the home end of the distance.
signal wire C is connected, as before described, say, by means of a lever G turning.
on a fulcrum on the framing N of the apparatus, or by a chain carrier over. pulleys,.

page_text: with weight for counterbalancing the weight of the empty box B. The wire C from
the distance signal A is passed over and under guide pulleys M, M, and thence
between the loose pulleys and at the head end of the signal lever L, and over
a loose pulley on the fulcrum pin of the said lever, as before described. The
distance signal wire C then passes round a detent or stop wheel I, as described
before. The home end of the wire C is connected to the end of the lever G.
The weight box B contains fluid as before. This box forms the automatically
varying compensating weight aforesaid. The supply pipe band the wasto pipe
are cach provided with a cock or valve c and c respectively as before. P is the
lever for giving the signalman facility for independent adjustinent of the wire, and
thus calling into action the automatic adjustment of the tightening or slackening.
of the wire by means of the variable weight of the box B. When the signalman
thus finds, for instance,. that the wire is too slack, and the state of tension of the
wire is at once felt by the ease or otherwise with which the signal lever L is worked,
he pushes over the lever P in the direction of the arrow, the lower end of the lever
will then depress the rod p and the left hand of the lever Q, the opposite end of
the latter will be raised, and the vertical bar connected thereto will also be raised
thereby, and through the intervention of the lever S, rod T, and lever U, the supply
valve c in the supply. pipe b will be opened, admitting water to the vessel B as the
bar R is thereby raised, the stud r thereon comes in contact with the lever 8, the
other end of which comes in contact with a stud on the detent rod K, throwing.
its tooth or teeth out of the detent or locking wheel I, which is then free to
revolve.
с
On the spindle or fulcrum pin of the detent wheel I is fixed a bevil wheel w,
Figure 1a, gearing into another bevil wheel on the spindle t, which is connected to
an indicator Z, the hand of which by suitable gearing indicates the amount, or pro-
portional amount of slack of wire taken up or released, and it also shews the.
position of the detent wheel. On returning the lever P to its middle position the
spring K¹ pushes the teeth of the bar K into the detent wheel, and locks the same.
When the signalman judges that enough slack has been taken up he returns the
lever P to its upright position, thereby locking the detent and causing the spiral
spring to close the supply valve c.
The box B is fitted with an overflow pipe b connected to the waste pipe b₁
below the valve c¹. In cold weather the box B may be almost or quite empty, and
the frost will consequently practically have no deleterious influence on the operation
of the valves, but the water may, if need be, where a supply cistern is used, be
mixed with glycerine to prevent freezing, as before stated. On the other hand,
if the signalman feels on his signal lever L that the wire is too tight, he moves
the lever P to the left; the bar R will then with its bottom end come in
contact with the lever X and depress it, thereby through the connecting rod Y
open the waste valve c². The. rod Y is connected to the rod y, which can
slide telescopically in the socket of the lever y¹. As soon as sufficient water
has run out of the box B the latter rises, the bar R being lowered by the
motion of the lever P. A projection 71 on the bar R comes in contact with
a stud on the detent rod K, and unlocks the detent wheel I; the signal wire is then
free to release itself; when the signalman judges that it is slack enough he pulls
the lever P back to its upright position; the spiral spring g causes the waste
valve c¹ to close. The studs on the detent rod K and on the bar e may be adjustable
screws.
The signal lever L may be used for working a pump which carries the fluid from
the waste cistern back to the supply cistern. The lever P thus allows of inde-
pendent adjustment of the signal wire whenever required.
The lever P is in this case also used for checking or stopping the operation of the
compensating apparatus at any time, or while operating the signal lever L. As-
there will always be times in which the expansion or contraction, though so great
that it ought to be taken into consideration, is not sufficient to cause the compen->

page_text: sating weight to act, the lever P should also in this latter arrangement be available
for use.
The lever P.thus in both cases places the apparatus entirely, and at all
times, within the control of the signalman.
And having thus described and ascertained the nature of this Invention, I
declare that I claim,-
Firstly. Tightening up a distance signal wire by means of an automatically
adjustable weight operated automatically or by hand gear, substantially as described
with reference to the accompanying Drawings.
Secondly. The application of an automatically adjustable weight operated nuto-
matically or by hand gear, in combination with any suitable detent or locking
apparatus or brake for holding the signal wire, substantially as set forth.
Thirdly. The arrangement of pulleys on the signal lever, substantially as set-
forth.
Fourthly. The signal wire detent or locking apparatus, substantially as set forth.
In witness whereof, I, the said Charles Brett, have hereunto set my hand and
seal, this Twenty-third day of November, in the year of our Lord One
thousand eight hundred and seventy-seven.