IMPROVEMENTS IN HYDRAULIC LIFTS
Year: 1880

page_text: LETTERS PATENT to Edward Bayzand Ellington, of the Hydraulic Engineering
Works, Chester, in the County of Chester, for an Invention of "IMPROVEMENTS
IN HYDRAULIC LIFTS."
PROVISIONAL SPECIFICATION left by the said Edward Bayzand Ellington
at the Office of the Commissioners of Patents on the 9th December 1880.
EDWARD BAYZAND ELLINGTON of the Hydraulic Engineering Works Chester
in the County of Chester. "IMPROVEMENTS IN HYDRAULIC LIFTS."
I
My Invention relates to the construction and arrangement of a hydraulic lift in
such a manner that not only the permanent weight of the cage and ram but also
the variable weight of ram resulting from its greater or less protrusion from its
cylinder is compensated without the use of chains and pullies. For this purpose
connect the lift cylinder to the lower part of a vertical cylinder of larger area, the
upper part of which is connected to the accumulator or reservoir containing water
under pressure.
This cylinder is fitted with a piston having a trunk protruding
through packing at the bottom of the cylinder. And the trunk itself is made
hollow so as to constitute a cylinder into which protrudes through packing a
plunger fixed to the top of the main cylinder, a passage being formed through this
plunger which puts the cylinder in which it works in communication with the
accumulator or reservoir. I make the weight of the trunk piston and the area of
the plunger such that when the latter is subjected to pressure from the accumulator
or reservoir it along with the said weight balances the invariable part of the
weight of the lift ram and cage. When the piston itself is subjected to the
pressure from the accumulator or reservoir, it descends causing the lift to ascend
and the increasing pressure on the piston due to the increasing column of water
above it compensates the increase of weight of the lift ram due to its greater
protrusion from its cylinder. Although I have described a mode of compensating
in which a moving trunk piston with a stationary internal plunger is employed, this
being a compact form of apparatus, the arrangement may be modified, as for

page_text: example by employing a stationary piston and a moving heavy cylinder, or by
arranging the plunger to work in a cylinder separate from the trunk; or generally
by arranging a heavy part to descend while the lift ram ascends, the heavy
descending part being subjected to the pressure of a head of water increasing as it
descends in proportion as the head acting on the ram of the lift decreases as the
ram ascends. In many cases where the moving part can be made sufficiently heavy
the plunger or its equivalent for making up part of the balance by pressure may be
dispensed with. In some cases it is of advantage to connect the apparatus to two
separate accumulators or reservoirs so that one of the working parts can be
subjected to pressure different from that to which the other is subjected.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Bayzand Ellington in the Great Seal Patent Office on the
8th June 1881.
EDWARD BAYZAND ELLINGTON of the Hydraulic Engineering Works Chester
in the County of Chester. "IMPROVEMENTS IN HYDRAULIC LIFTS."
My Invention relates to the construction and arrangement of a hydraulic lift in
such a manner that not only the permanent weight of the cage and ram but also
the variable weight of ram resulting from its greater or less protrusion from its
cylinder is compensated without the use of chains and pullies. For this purpose
I connect the lift cylinder to the lower part of a vertical cylinder of larger area,
the upper part of which is connected to the accumulator or reservoir containing
water under pressure. This cylinder is fitted with a piston having a trunk
protruding through packing at the bottom of the cylinder. And the trunk itself is
made hollow so as to constitute a cylinder into which protrudes through packing a
plunger fixed to the top of the main cylinder, a passage being formed through this
plunger which puts the cylinder in which it works in communication with the
accumulator or reservoir. I make the weight of the trunk piston and the area of
the plunger such that when the latter is subjected to pressure from the accumulator
or reservoir it along with the said weight balances the invariable part of the
weight of the lift ram and cage. When the piston itself is subjected to the pressure
from the accumulator or reservoir, it descends causing the lift to ascend and the
increasing pressure on the piston due to the increasing column of water above it
compensates the increase of weight of the lift ram due to its greater protrusion
from its cylinder. Although I have described a mode of compensating in which a
moving trunk piston with a stationary internal plunger is employed, this being a
compact form of apparatus, the arrangement may be modified, as for example by
employing a stationary piston and a moving heavy cylinder, or by arranging the
plunger to work in a cylinder separate from the trunk; or generally by arranging
a heavy part to descend while the lift ram ascends, the heavy descending part
being subjected to the pressure of a head of water increasing as it descends in
proportion as the head acting on the ram of the lift decreases as the ram ascends.
In many cases where the moving part can be made sufficiently heavy, the plunger
or its equivalent for making up part of the balance by pressure may be dispensed
with. In some cases it is of advantage to connect the apparatus to two separate
accumulators or reservoirs so that one of the working parts can be subjected to
pressure different from that to which the other is subjected.
The accompanying Drawings represent various arrangements of apparatus
according to iny Invention for counterbalancing the permanent and varying load
due to the cago and ram of a hydraulic lift. In the Figures which I am about to
describe the parts which correspond with each other are marked by similar
reference letters. According to the arrangement shewn in Fig. 1 the lift cylinder A
is connected by the pipe B with the lower end of a cylinder (fitted with a trunk
piston D. The upper end of the cylinder C communicates by a pipe E with an
accumulator or reservoir giving suitable pressure. The trunk of the piston D is
connected to another piston F working in a cylinder G the upper end of which is
connected by the pipe H with the working valve K. This valve is connected with
the pipe L which supplies water under pressure from the reservoir or accumulator
and with the discharge M. When the valve makes communication between H
and L then the pressure acts on the annular area of the piston F, and this together
with the pressure acting on the upper side of the piston D causes the two
pistons D and F with their connecting trunk to descend forcing water by the
pipe B into the lift cylinder A. The lift plunger and platform are thus raised and
as the liquid column acting on D and F increases in the same proportion as the
lift plunger ascends, the counterbalance of the platform and plunger remains

page_text: constant during the ascent of the plunger. On shifting the valve K so as to close
the communication with L and open communication to the discharge M the lift
platform and plunger descend causing the pistons D and F to rise. As they rise
they become subject to the pressure of a liquid column decreasing in the same
proportion as the lift plunger descends thus maintaining a constant counter-
balance. By means of cocks N and O the lift cylinder can be charged when
required. The cock O is usually open to the air and the cock N is closed. For
the purpose of charging, both cocks are moved so as to open communication with
the pipe L thus the pistons F and D are raised the lift plunger remaining down.
According to the arrangement shewn in Fig. 2 the piston F is made with a hollow
trunk C working over a stationary plunger P which is the continuation of the
pipe E; the bottom 1) of the trunk C is thus always subject to the pressure com-
municated by the pipe E. In the arrangement shewn at Fig. 3 the piston D has a
hollow trunk working over a plunger T which is a continuation of the pipe B
leading to the lift cylinder. In this case the lift is raised by opening the valve K
to the discharge the annular area on the underside of D being thus relieved from
pressure while its upper side is subject to the pressure communicated by the pipe E.
For lowering the lift the valve K is shifted so as to bring the pressure pipe L into
communication with H, and the annular area on the underside of D is thus
subjected to pressure which aids that communicated from the lift cylinder to
raise D. In the arrangement shewn in Fig. 4 plungers D and F are substituted for the
pistons D and F operating as described with reference to Fig. 1, the continuation
of the pipe B forming a tubular plunger T working within the hollow plunger F.
Fig. 5 shews a similar arrangement with a solid plunger T attached to F and
working in a cylinder Q which communicates with the lift cylinder by the pipe B.
In the arrangements shewn in Figs. 6 and 7 heavy plungers R and T or a heavy
piston S and its trunk are employed to counterbalance the permanent load of the
lift platform and plunger, the additional pressure for raising these being given by
putting the pipe L in communication with H. In both these cases as the plunger R
or piston S descends proportionally to the ascent of the lift plunger and conversely,
the height of column pressing varies with the varying pressure resulting from the
movement of the lift plunger. In the arrangement shewn in Fig. 8 the cylinder G
with which the pipe H communicates has a hollow plunger working over two
stationary plungers, P the continuation of the pipe E, and T the continuation of
the lift pipe B. In the arrangement shewn in Fig. 9 the action is the same as
described with reference to Fig. 6, the piston R with its plunger T being loaded
with a weight W suspended from it by bolts.
Having thus described the nature of my Invention and in what manner the
same is to be performed, I hereby declare that I make no general claim to counter-
balancing the cage and ram of a hydraulic lift by weights or by fluid pressure or
by both conjoined, but I claim in respect of apparatus of that kind :-
The use of a vertical compensating cylinder with its piston or plunger so
arranged in relation to the lift cylinder and to the supply of water under pressure
that the liquid column acting on the compensating piston or plunger increases
proportionally to the protrusion of the lift plunger, substantially as and for the
purpose herein set forth.
In witness whereof I the said Edward Bayzand Ellington have hereunto set
my hand and seal this Fourth day of June in the year of our Lord One
thousand eight hundred and eighty one.