IMPROVEMENTS IN APPARATUS FOR COMMUNICATING BETWEEN THE GUARDS, DRIVERS, AND PASSENGERS OF RAILWAY TRAINS
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by John Mc Elroy and Charles
Kearsley at the Office of the Commissioners of Patents, with their
Petition, on the 26th February 1870.
We, JOHN MC ELROY, of Sale, in the County of Chester, and CHARLES
KEARSLEY, of Manchester, in the County of Lancaster, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN APPARATUS FOR
COMMUNICATING BETWEEN THE GUARDS, DRIVERS, AND PASSENGERS OF RAILWAY
TRAINS," to be as follows:-
This Invention consists in certain improvements in the construction
and arrangement of apparatus whereby signals can be communicated
from one part of a railway train to another in a simple and effectual
manner.
In carrying this Invention into effect two ropes, cords, or chains are
placed alongside each other from one end of the train to the other, such.
ropes, cords, or chains being either in continuous lengths, or in separate
lengths connected with each carriage, and which can be attached to

page_text: each other when the train is put together for a journey. The ends of
the two ropes, cords, or chains which come into the guard's van are
attached to a differentially acting apparatus which is placed therein, and
which works the alarum in the van. In cach carriage a bell pull is
connected by an attachment to one of the two ropes, cords, or chains,
in such a manner as to leave the same free to move longitudinally, but
draws it inwards and contracts it when the bell pull is drawn.
The differential apparatus is of such a nature that when both ropes,
cords, or chains are pulled out or slackened together, either from the
carriages changing their relative distances from each other or from-any-
other cause, no disturbance is given to the alarum, but if one rope, cord,
or chain be pulled or slackened and the other not then the difference
created thereby in the extension of the two ropes, cords, or chains causes
a relative displacement in the moving parts of the apparatus, and the
alarum is actuated. In this manner the varying distances of the
carriages relatively to each other have no effect in disturbing the
alarum, the slack being taken up by a weight or weights or springs
in the van, and the apparatus is always in a position to receive signals
however the carriages may change their relative positions during the
journey.
The differential apparatus may be of various forms, but the following
are those which by preference, are adopted in connection with this
Invention:
In one form a pulley or wheel, herein-after called the rope wheel, is
used, the same having a groove in its periphery for receiving the pair of
ropes, cords, or chains. A weight is connected with the pulley to keep
up a proper degree of tension. One of the ropes, cords, or chains passes
direct to the other end of the train and to the engine, and the other rope
firstly passes between two fixed pulleys down to and over a moving
pulley which works the alarum (and which may be termed the differential.
pulley) and thence to the ends of the train. When both ropes, cords,
rope wheel will give off as
or chains are pulled out together equally the
as much rope on one side of the differential pulley as is taken from it on
the other side. The latter will therefore not change its place and the
alarum will not be disturbed, but if one of the ropes; cords, or chains,
for instance, that passing over the differential pulley, is pulled and the
other not, then the other rope cord, or chain being held tight by the

page_text: weight, the pull will have the effect of drawing up the differential pulley
and of sounding the alarum.
In a second mode of arranging the apparatus each of the ropes, cords,
or chains is wound round a separate wheel on the same axle, one being
fast and the other loose on the axle, but checked by stops from rotating
above a certain distance on one side more than on the other. Between
the pulleys and attached to one of them is a spring, and in a bar attached
to the spring is a hole through which a pin from the other wheel passes.
The fast wheel is weighted as before mentioned. Attached to the bar is
a chain which connects it to the lever of a bell fixed on the fast wheel
and the bar, and consequently the loose wheel is prevented by stops
from rotating more than a certain distance from the fast wheel.
In a third plan two rods are arranged so as to cross over cach other,
the same being connected by means of a pin which passes through their
centres and round which they are free to move.
From corresponding
ends of these rods are jointed two other rods and the opposite ends of
the latter are jointed to a sliding collar or sleeve which is capable of
sliding along a fifth rod which is capable of rotating freely round the
same pin as the two rods firstly mentioned. The extremity of the fifth
rod is attached to the alarum. The ropes pass through the unconnected.
ends of the two rods firstly mentioned and thence to the end of the train,
being weighted as before mentioned.
Under a fourth arrangement the ropes, cords, or chains are coiled
round two wheels in contrary directions. Each of the wheels is fastly
secured to a bevil toothed wheel which is loose on the same axle. A
third or intermediate bevil wheel is geared between the other two, thus
forming a train of three wheels. The intermediate wheel is free to
rotate round the common shaft and also round its own axle, which
latter is prolonged outside the wheel and is attached to and works the
alarum.
In a fifth arrangement the two rope wheels are placed on a screwed.
shaft. One of such wheels is fixed fast to the shaft, and the other is
free to move on the screwed part in the manner of a nut, a lever being
arranged to work in a groove in its boss, and which lever is attached to
the alarum.
It may be observed that in cases in which the guard's van is not placed
at the end but at some other part of the train, the ends of the ropes, cords,

page_text: or chains are not fastened directly to the apparatus, as before described,
but are passed over moving pulleys into the guard's van; such moving
pulleys are then connected by cords to the apparatus, and in this manner
the slack of the forward or backward part of the train will be taken up
independently of each other by the same weight in the van.