Improvements in Working Hydraulic Lifts, Cranes, and other Appliances, and in Apparatus therefor.
Year: 1894

page_text: Date of Application, 22nd May, 1894
Complete Specification Left, 22nd Feb., 1895-Accepted, 13th May, 1895
PROVISIONAL SPECIFICATION.
Improvements in Working Hydraulic Lifts, Cranes, and other
Appliances, and in Apparatus therefor.
I, WILLIAM ARTHUR KER, of 2, Kingdon Road, West Hampstead, in the
County of Middlesex, Engineer, do hereby declare the nature of this invention to
be as follows:
This invention relates to an improved method of and apparatus for working
hydraulic lifts, cranes and other appliances where the load is variable ; primary
object being to regulate the consumption of water in proportion to the load to be
raised, and in some instances, by utilizing the weight of the load in a descending
cage, to effect economy by forcing water into a pressure-reservoir.
In carrying out my invention, I employ two or more power-cylinders provided
with rams and arranged in such a manner as to act as auxiliaries to the lifting ram
cylinder; high pressure water being admitted to one or more of the power-
cylinders according to the weight to be raised; the capacity of the idle cylinder or
cylinders thus representing substantially the difference between the load actually
lifted and the maximum capable of being lifted, and consequently the volume of
water economised.
I will now proceed to explain by way of example the application of my invention
to a hydraulic lift with separate balance.
The lift-cylinder is connected by means of suitable pipes with a balance-cylinder
and ram; small power-cylinders being mounted upon or otherwise disposed outside
the balance-cylinder. A series of weights are placed on the balance-cylinder,
by which the requisite pressure is maintained on the water in that cylinder to
balance the lift and its appurtenances. A valve or valves is or are provided for
admitting water to one or more of the power-cylinders and for allowing water to.
escape therefrom.
When a small weight only has to be lifted, water is admitted from the pressure
main or other source of supply to one or more of the power-cylinders, whereupon
the balance-cylinder and power-cylinders are forced down together, thereby
causing water to flow into the lift-cylinder to raise the lift. When, however, a
comparatively heavy load has to be raised, water is admitted to an additional
power-cylinder or to additional power-cylinders. While the lift is descending,
water may be allowed to flow from the lift-cylinder to the balance-cylinder and
from the additional power-cylinders to an exhaust reservoir; or, under certain
conditions as to load, water may be forced from one or more of the power-
cylinders into an accumulator or pressure reservoir, and so rendered available for
future use.
A pilot-valve, which may be of the usual kind and adapted to be worked by the
lift attendant in the lift-cage by a rope or rod, admits water from the pressure-main to
an automatic valve for regulating the supply to the power-cylinders, and to allow
water to flow from the power-cylinders to an exhaust water tank or drain, and in
some cases to permit water to flow into and out of the idle power-cylinder or
power-cylinders. The automatic valve may be connected in any convenient way
to a piston working in a cylinder. One end of the cylinder is in communication
with the lift-cylinder, preferably at a point where there is no How of water,
the other end of the cylinder being in communication with the pipe connecting

page_text: the lift-cylinder with the balance-cylinder. This pipe may be reduced in
diameter at the point where communication is effected with the cylinder
pertaining to the automatic valve, so that the speed of the water at that point
while the lift is in motion may be increased; or it may be larger in diameter at
such point so as to decrease the speed of the water there. In either case, the
alteration in the diameter of the pipe is gradual, and several bosses are provided,
so that the pipe leading to the cylinder for working the automatic valve may be
connected by means of the one which will give access to that part of the pipe
wherein the water flows at the proper rate for enabling the lift to work at the
desired speed.
When the lift is not in motion, there is no flow of water through the main
connecting pipe, and the opposite sides of the piston being of the same area and
subject to the same pressure per unit of area, the piston is, in equilibrium. When
the lift moves, the water flows rapidly through the main pipe, its pressure being
thus reduced. The pressure on one side the piston in the cylinder pertaining to
the automatic valve is consequently reduced, the pressure on the opposite side
being maintained because the water in the lift-cylinder at the point of connection
with this side is not in motion and its, pressure therefore remains the same, with
the result that the piston moves and actuates the automatic valve, thus regulating
the supply of water to the power-cylinders. A weight, spring or hydraulic
cylinder may be employed for causing the automatic valve after the stoppage of
the lift to return to its normal position upon the pressure on the one side of the
piston again becoming equal to that on the other side.
Dated the 21st day of May 1894
Improvements in Working Hydraulic Lifts, Cranes, and other
Appliances, and in Apparatus therefor.
I, WILLIAM ARTHUR KER, of 2, Kingdon Road, West Hampstead, in the
County of Middlesex, 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 relates to an improved method of and apparatus for working
hydraulic lifts, cranes and other appliances where the load is variable; its
primary object being to regulate the consumption of water in proportion to the
load to be raised and in some instances, by utilizing the weight of the lọad in a
descending cage, to effect economy by forcing water into a pressure-reservoir.
In carrying out my invention, I employ two or more power-cylinders provided
with rams and arranged in such a manner as to act as auxiliaries to the lifting
ram cylinders; high pressure water being admitted to one or more of the power-
cylinders according to the weight to be raised; the capacity of the idle cylinder
or cylinders thus representing substantially the difference between the load
actually lifted and the maximum capable of being lifted, and consequently the
volume of water economised.
In the accompanying drawings, the application of the invention to the working
of hydraulic lifts is illustrated;
Fig. 1 showing the cage supported upon a ram, and
Fig. 2 the cage suspended from a chain and counter-balanced in the usual

page_text: Fig. 3 is a longitudinal section of the automatic valve for regulating the supply
of water to the power-cylinders; Fig. 4 being a side elevation thereof.
The lift-cylinder A is connected by a pipe awith the trunk Biof a balance-
cylinder C; small power-cylinders DD' being mounted upon or otherwise disposed
outside the balance-cylinder. A series of weights W are added to the platform of
the balance-cylinder C by which the requisite pressure is maintained on the water in
that cylinder to balance or partly balance the lift L and its appurtenances. Valve
apparatus E, hereinafter more particularly described, is provided for admitting
water to one or more of the power-cylinders and for allowing water to escape
therefrom.
When a small weight only has to be lifted, water is admitted from the
pressure-main for other source of supply to one or more power-cylinders D,
whereupon the balance cylinder C and power-cylinders D D are forced down
together, thereby causing water to flow to the lift-cylinder A to raise the lift.
When, however, a comparatively heavy load has to be raised, water is-admitted
to one or more power-cylinders D. While the lift is descending, water may
be allowed to flow from the lift-cylinder A to the balance-cylinder C and from
the auxiliary power-cylinders D D to an exhaust reservoir F; or, under certain
conditions as to load, water may be forced from one or more of the power-
cylinders into an accumulator or pressure reservoir, and so rendered available
för future use.
A pilot-valve G which may be of the usual kind and adapted to be worked
by the lift attendant in the lift-cage by a rope or rod g, admits water from the
pressure-main f, through the pipe i, to the valve apparatus E, the action of
which is automatically regulated by a controlling device Has hereinafter
explained. The water passes from the valve apparatus E by way of the
pipes to the power-cylinders D D' according to the duty to be performed
and the automatically assumed position of the controlling valve.
The construction and mode of operation of the valve apparatus E and
controlling device H will be more readily understood if reference be had to
Fig. 3 in supplement to Fig. 1. To a piston-valve e working in a cylinder el
is connected a piston h working in a cylinder h. The latter cylinder is at one
end, by means of a pipe h, in connection with the lift cylinder A or with the
pipe a near its junction with the lift-cylinder, the other end of the cylinder
being in communication by way of the pipe with the pipe a connecting the
lift-cylinder A with the balance-cylinder C. The cylinder e' is connected at e
with the pressure-main i, and at ee with the auxiliary power-cylinders D D¹.
There is also a connection by way of e and a pipe k with a storage tank F
for the reception of water which flows into and out of the auxiliary power-
cylinders when idle, that is to say, when not supplied with power water.
pipe a may be reduced in diameter between the point where communication.
is effected with the controlling device H and the point y, so that the speed of
the water at the contracted part may, while the lift is in motion, be increased,
the fluid friction increased and the effective pressure beyoud that point
diminished in consequence of such frictional loss. The contraction of the pipe a
is not however essential, as the same effect is produced by making the point of
connection at such a distance from the point of connection y as to bring into
use a length of pipe sufficient to occasion such an amount of frictional resistance
as will effect the requisite reduction of pressure.
The
When the lift is not in motion, there is no flow of water through the connecting
pipe a, and the opposite sides of the piston being of the same area and subject to
the same pressure per unit of area, the piston is in equilibrium. When the lift
rises, water flows rapidly through the pipe a, its pressure at the point y being
distinctly less than at the point a owing to frictional resistance met with whilst
traversing the section of the pipe x-y. The pressure upon the upper side of the
piston becoming in consequence less than that upon the under side, the piston
rises and lifts the valve e, thus regulating or shutting off the supply of water to

page_text: the power-cylinder or cylinders D or to the power-cylinders or sets of cylinders D
and D'. A weight w or equivalent means may be employed to ensure the return
of the piston h and valve e to their normal positions upon the stoppage of the lift
and the pressure upon the opposite sides of the piston again becoming equalised.
In Fig. 2, the valve apparatus E is in communication with the auxiliary power-
cylinders D D and with the power-cylinder C by means of the pipes m m³, the
supply of water from the pressure-main flowing thereto through the pipe. The
cylinder of the controlling device H is in this instance open at one end to
the pressure-pipe i, whilst the other end is in communication with the power-
cylinder C. Upon the lift moving at too great a speed in consequence of the
power being seriously in excess of the load, owing to frictional loss along the
pipes, m', there is a substantial loss of pressure between the point and
the point y.
The pipes a a communicate the pressures existing at the points y
respectively to the lower and upper ends of the cylinder of the controlling device H,
an effect ensuing so far as regards the operation of the controlling valve e of a
character similar to that described with reference to Fig. 1.
.
It will thus be seen that if the pressure be seriously in excess of that required
for raising a given load, the speed at which the lift commences to travel entails a
high velocity for the water passing from the balance-cylinder, accumulator or other
immediate source of supply to the lift-cylinder or its equivalent. This high velocity
entailing friction and consequent diminution of relative effective pressure at the
point y as compared with that prevailing at the point a, the piston h rises, lifts the
regulating valve e, shutting off first the auxiliary power-cylinder or cylinders D
and, ultimately, if the action be sufficiently intense, the auxiliary power-cylinder
or cylinders D¹.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :-
1. The improved method of working hydraulic lifts, cranes and similar appliances,
substantially as herein described and whereby the supply of pressure water is
automatically controlled and proportioned to the load to be raised.
2. In the working of hydraulic lifts, cranes and similar appliances where auxiliary
power-cylinders are employed, rendering such auxiliary power-cylinders severally
subject to the control of an automatic regulator, the action of which is dependent
on difference of pressure temporarily existing at different points in the pipe
conveying power water to the lilt-cylinder or its equivalent.
3. For use in connection with hydraulic lifts and like installations in which
auxiliary power-cylinders are employed in the manner herein referred to, an auto-
matic regulator, comprising a cylinder containing a piston and having its opposite
extremities in communication at different points with the pipe conveying power
water to the lift-cylinder or its equivalent, the said piston being connected to and
operating a valve arranged in such a manner as to cut off the supply of water to
the auxiliary power-cylinder or cylinders upon the lift exceeding its normal speed
of travel.
Dated the 22nd day of February 1895.