Improved Means of Compensating Railway Signal Wires.
Year: 1895

page_text: Date of Application, 21st Dec., 1895-Accepted, 25th Jan., 1896
Improved Means of Compensating Railway Signal Wires.
FRANK BROOKS HART, 149 Manchester Old Road, Heaton Chapel, Manchester
Civil Engineer do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement:-
This invention is a mechanical arrangement providing against defective operation
of signal arms consequent upon the contraction and expansion of signal wires caused
by change in atmospheric temperature.
The appliance is applicable to all ordinary single signals and to signals controlled
by two or more pointsmen and technically termed slotted signals.
The manner of application is as follows;-
In the case of a single signal controlled by one pointsman only, the wire from
the signal cabin to the signal post on which the arm works, is fixed in an unbroken
length and attached to the power end of the balance lever (hereinafter termed
No. 1 lever) in the usual way, a weight being fixed to the other end of the lever.
There is no direct connection between this lever and the rod which actuates the
signal arm.
Another lever-a counterbalance lever-is mounted by the side of No. 1 lever
on the same bracket and working on the same fulcrum.
A weight is attached to the counterbalance lever on the same side of the fulcrum
as the power or wire end of No. 1 lever, and the operating rod working the signal
arm is connected to the counterbalance lever at the opposite end to the weight
mentioned.
A small or T piece is forged to the underside of the counterbalance lever
at the opposite side to the weight and on the same side as the weight of
No. 1 lever.
This piece clips or underlies No. 1 lever so that the counterbalance lever is held
down until released by the operating of No. 1 lever which, as before described, is
directly connected by means of the wire to the lever in the cabin. The signal arm
is then operated by means of the counterbalance lever & weight.
The or T piece described may be duplicated on the other side of the counter-
balance lever overlying No. 1 lever.
A lug or lugs may be put on the balance casting to stop the counterbalance lever
travelling beyond a fixed or required distance, such distance or sweep to allow the
signal arm to be properly actuated to one angle at each operation. This is effected
by the Lor T piece attached to the counterbalance lever striking the stop on
the casting.
The same result may be attained also by filling up the casting on the ledge of
the balance bracket under the weight side of the counterbalance lever.
A short chain or its equivalent connecting the signal wire with the post answers
the same purpose.
Thus by any of the foregoing means the stroke or sweep of No. 1 lever is made
from two to three times greater than the stroke of the counterbalance lever.
The counterbalance lever is made about the same length as No. 1 lever on the
same side as the weight of No. 1 lever.

page_text: The weight of No. 1 lever and the end of the counterbalance lever, on the same
side as the weight of No. 1 lever, are connected by means of a chain rope link or
the equivalent thereto, of such length as shall not interfere with the proper working
of either of the levers.
Should therefore No: 1 lever break or the weight fall off, the weight through
the chain will act upon the end of the counterbalance lever throwing the signal
arm to danger.
Slotted signals are treated in the same manner.
For every working wire a lever similar to No. 1 lever is provided, and for every
signal arm to be operated a counterbalance lever is mounted working in conjunction
with lever similar to No. 1 lever, & with all necessary stops and chains described.
Referring to the drawings and Figs. 1, 2 & 3, a is the wire from the signal cabin
to the signal post, passing round the pulley wheel b. The wire is attached to the
balance lever c hereinbefore termed No. 1 lever.
The counterbalance lever d is mounted on the same fulcrum e on the bracket f.
The balance lever c has a weight g attached to its extremity, and the counter-
balance lever d has also a weight h fixed to the lever as shewn.
The lower extremity of the operating rod i is secured to the counterbalance
leverd at a point j.
The rod i operates the arm k.
ว
The or pieces are forged or secured to the counterbalance lever d and
underlying and overlying the lever c as shewn.
The filling piece
m acts as a stop block for counterbalance lever d the underside
of which rests on the top of the piece m.
The counterbalance lever d is extended and made about the same length as
lever c on the same side as the weight g.
The counterbalance lever d'is extended to give leverage, so that weight 9, in the
event of breaking away from lever d, by being suspended to lever d by chain n,
will overcome weight hand put the signal arm to danger.
Chain n connects weight g with extremity of lever dat o and is provided for the
purpose just described.
The counterbalance lever d is operated, by the lifting of lever c, to its full extent at
position d' Fig. 3, and the signal arm is then off to a maximum angle.
Therefore, as the lever d is controlled by the lever c, when the lever c occupies
a similar position as lever dat d' Fig. 3 the lever c has accomplished the whole
work required; but it is still free to travel until the maximum stroke or position c¹
Fig. 3 is reached. All stroke then, of the lever c, between positions d¹ and c¹ is
compensation and is calculated to give all the variation required to take off the
signal arm properly at each operation by the pointsman in all temperatures.
If the weather is cold and the wire tight and contracted the lever c will be
carried to position or thereabouts when operated; if the weather be warm the
lever c will be lifted, when operated, only to position d' or thereabouts, but still the
signal arm will be properly actuated.
Figs. 4 & 5 shew bracket casting ƒ for levers, and a stop.m equivalent to the
stop m Figs. 1 & 3.
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
1. In single worked signals, controlled by one pointsman only, the use of the
counterbalance lever and weight in addition to the ordinary lever as described.
2. In single worked signals and signals operated & controlled by two or more
pointsmen the use of the stop for the counterbalance lever as described.
3. In single worked signals and in signals operated & controlled by two or more
pointsmen the use of the extended counterbalance lever.
4. In single worked signals and in signals operated & controlled by two or more

page_text: pointsmen the use of the protecting chain from weight of balance lever to extremity
of counterbalance lever.
5. In single worked signals and in signals operated & controlled by two or more.
pointsmen the use of the two T or L pieces instead of one as used heretofore.
Dated this 11th day of October 1895.
FRANK BROOKS HART.