Improvements in Apparatus for Taking Up the Slack in Wires Operating Signals and other Mechanism from a Distance.
Year: 1886

page_text: Date of Application, 4th May, 1886.
Complete Left, 1st Feb., 1887.
Complete Accepted, 1st Mar., 1887.
Improvements in Apparatus for Taking Up the Slack in Wires
Operating Signals and other Mechanism from a Distance.
We JOHN COLEMAN and ISAAC HENSON both of Derby in the County of Derby
Engineers do hereby declare the nature of this invention to be as follows:-
This Invention has for its object-improvements in apparatus for taking up the slack
in wires operating signals and other mechanism from a distance.
This apparatus is to be placed about midway of the length of the wire and it consists
of a frame carrying pulleys around which a short length of chain interposed in the
length of the wire is carried. The chain passes over the tops of two upper pulleys
and under a third or intermediate pulley. The intermediate pulley is weighted and it
can rise and fall in vertical guide grooves in the frame which carries the pulleys. The
weight added to the pulley is sufficient to keep the wire taut on either side of the
apparatus but not sufficient to overcome or interfere with the action of the weight on
the signal post which raises the signal arm to the danger position. So long as the
signal arm remains raised the lower pulley is perfectly free to rise or to fall in
accordance with the contraction or expansion of the wire, but immediately the wire is
pulled from one end with the object of lowering the signal arm at the other end the
bearings of the movable pulley become locked fast in position and then by the move-
ment of the wire the weight at the signal post is raised and the signal arm is lowered.
In order thus to secure the moveable pulley when the signal wire is pulled we make
use of a hydraulic arrangement which we prefer to be as follows:-
The moveable pulley is carried in a fork at the lower end of a piston rod and on the
piston rod there is a piston contained in a cylinder. The cylinder communicates with
a cistern in which liquid is held and so the cylinder is kept constantly full. In the
passage between the cylinder and the cistern there is a valve which when the apparatus
is at rest and the signal arm raised, remains open and the moveable pulley is free to
rise and fall as may be required to compensate expansion or contraction of the signal
wire. When the signal wire is pulled to draw down the signal arm the tightening
of the wire causes the piston to commence to move within the cylinder and the

page_text: tendency is for the liquid then to flow back from the cylinder into the cistern, this
tendency however is immediately checked by the closing of the valve, and then the
piston with the intermediate pulley are unable to yield further and the pull on the wire
operates to lower the signal arm. So long as the wire remains strained the valve
rests in its seat and the signal arms remains in the position to which it has been
lowered, but immediately the wire is released and allowed to become slack (with the
object of permitting the signal arm again to rise to the position termed the "danger"
position) the pressure within the cylinder is relieved, the valve falls away from its seat
and the moveable pulley is once more free to take up any position requisite to keep the
wire taut and ready for action. Then for so long as the signal arm remains raised the
movable pulley is free to adjust itself and the weight maintains an uniform strain upon
the wire, but immediately the wire is suddenly pulled with the object of raising the
signal arm the valve closes and the bearings of the pulley become temporarily
immovable as already described.
CARPMAEL & Co.,
Agents for the Applicants.

page_text: Operating Signals and other Mechanism from a Distance.
We, JOHN COLEMAN and ISAAC HENSON both of Derby in the County of Derby,
Engineers, 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 has for its object improvements in apparatus for taking up the slack
in wires operating signals and other mechanism from a distance.
This apparatus is to be placed about midway of the length of the wire and it consists
of a frame carrying pulleys around which a short length of chain, interposed in the
length of the wire, is carried. The chain passes over the tops of two upper pulleys
and under a third or intermediate pulley. The intermediate pulley is weighted and it
can rise and fall in the frame which carries the pulleys. The weight added to the
pulley is sufficient to keep the wire taut on either side of the apparatus but not
sufficient to overcome or interfere with the action of the weight on the signal post
which raises the signal arm to the danger position. So long as the signal arm remains
raised the lower pulley is perfectly free to rise or to fall in accordance with the
contraction or expansion of the wire, but immediately the wire is pulled from one end
with the object of lowering the signal arm at the other end the bearings of the movable
pulley become locked fast in position and then by the movement of the wire the weight
at the signal post is raised and the signal arm is lowered. In order thus to secure the
movable pulley when the signal wire is pulled we make use of a bydraulic arrangement
which we prefer to be as represented by the annexed drawings.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation partly in section.
Figure 2 is an end elevation.
aa is a fixed frame supporting the cylinder and also the axes or studs e¹ e
on which the pulleys e care free to turn. d is a moveable pulley between the
pulleys c c. e is a chain interposed about midway in the length of the signal wire
extending say from the signal cabin to the signal post. The axis of the pulley dis
carried in a fork at the lower end of the rod; it extends on either end beyond the
fork and receives upon it the disc weights g*g*. As many weights are here applied
as may be found necessary to keep the wire taut and no more. The rod enters the
cylinder through a gland at and at its upper end it carries the piston g. There is
a perforation g' in the rod fleading from one side of the piston to the other. h is the
cylinder end it forms part of a small reservoir which (although it is not so shown
in the drawing) we preferably make with a cover bolted on so that it may be removed
without difficulty. There is a vent hole in the cover. An aperture at h² with a valve
seat around it is provided in the cylinder end and to this aperture a valve i is fitted.

page_text: The cylinder and reservoir are charged with liquid not easily frozen.
The valve falls by gravity away from its seat as far as the adjustable screw stop
admits and this stop is so set that the valve closes freely when the piston suddenly
rises.
The action of the apparatus is as follows :—
Whilst the signal is at the danger position and the valve i is open the pulley d
together with the piston and piston rod can move freely to compensate any contraction
or expansion of the wire; liquid then entering or leaving the reservoir ¹ without
obstruction. When the wire is pulled from the signal cabin in order to raise the
weight at the signal post and lower the signal arm connected with this weight, the
piston g moves upwards in the cylinder for a short distance and until the valve i is
thereby caused to close. The piston rod is then prevented from entering further into
the cylinder, the cylinder being closed and full of liquid.
The pulley being unable to rise higher and having found an abutment the
continued pull of the chain raises the distant weight and lowers the signal arm as
required. So long as the signal arm remains down the liquid in the cylinder b
continues under pressure and the valve i rests closed.
When it is desired that the signal arm should return to the danger position by the
action of the weight at the signal post the wire is released at the signal cabin end and
the weight at the signal post being unsupported by the pull wire, falls and the signal
arm is raised. This movement takes place before the pulley d has descended far for
the descent is delayed by the liquid beneath the piston which can only pass by the
small perforation but after the signal arm has risen the pulley d continues its
descent until the wire on both sides of the apparatus is drawn taut.
It is obvious that the use of this apparatus is not limited to working signals, it is
applicable in other cases where apparatus has to be operated from a distance by a
draw-wire.
Having now particularly described and ascertained the nature of our said invention
and in what manner the same is to be performed we declare that what we claim is :-
1. Apparatus for taking up the slack in wires operating signals and other mechanism
from a distance in which the moveable pulley (or part which notwithstanding expansion
and contraction keeps the pull wire uniformly taut) is controlled by an hydraulic
cylinder with a valve which closes when the wire is suddenly pulled and so provides
the necessary abutment and which opens again when the wire is released and again
frees the compensating pulley or part substantially as described.
2. Apparatus substantially as described for taking up the slack in wires operating
signals and other mechanism from a distance.