IMPROVEMENTS IN THE MODE OF WORKING HYDRAULIC LIFTS
Year: 1865

page_text: LETTERS PATENT to William Clay, of the Mersey Steel and Iron Works,
Liverpool, in the County of Lancaster, Ironmaster, for the Invention
of "IMPROVEMENTS IN THE MODE OF WORKING HYDRAULIC LIFTS."
Sealed the 13th June 1865, and dated the 20th January 1865.
PROVISIONAL SPECIFICATION left by the said William Clay at the
Office of the Commissioners. of Patents, with his Petition, on the
20th January 1865.
I, WILLIAM CLAY, of the Mersey Steel and Iron Works, Liverpool, in the
County of Lancaster, Ironmaster, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MODE OF WORKING HYDRAULIC LIFTS," to
be as follows:-
The object of this Invention is to utilize the force of descending weights
where hydraulic pressure is used to raise loads from one level to another.
In working hydraulic lifts, according to my Invention, I pump the water
that is intended to set the hydraulic lift in operation into an accumulator or
receiver, from which the water at a suitable pressure is discharged into the
cylinder of the hydraulic apparatus in the usual manner for the purpose of
raising the load required to be elevated. When the apparatus is employed
for lowering a load, I employ the weight of the load to assist in returning the
water from the cylinder into the accumulator. This I effect by opening a
communication between the cylinder and the pumps of the engine employed
for charging the accumulator, and I thereby cause the back pressure of the
descending load to act upon and assist the pumps in returning the water in

page_text: the cylinder to the accumulator. By this means a great economy of the
engine power will be effected, the waste water or what has hitherto been
deemed the waste water of the cylinder (which is under great pressure) being
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Clay in the Great Seal Patent Office on the
20th July 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CLAY, of the Mersey Steel and Iron Works, Liverpool, in the County of Lan-
caster, Ironmaster, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twentieth day of January, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Clay, Her special licence that I, the said William
Clay, my executors, administrators, and assigns, or such others as I, the
said William Clay, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for " IMPROVE-
MENTS IN THE MODE OF WORKING HYDRAULIC LIFTS," upon the condition
(amongst others) that I, the said William Clay, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Clay, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawing hereunto annexed and to the
letters and figures marked thereon (that is to say) :-
The object of this Invention of "Improvements in the Mode of Working
Hydraulic Lifts" is to utilize the force of the dead weight of the platform, ram,
and other moving parts of the lift when descending. It will be obvious that

page_text: in addition to this utilization of the dead weight of the lift itself may be added
the weight of any descending load. The Invention is applicable to cases in
which hydraulic pressure is used to raise and lower loads from one level to
another.
In working hydraulic lifts in the ordinary manner, the water under a
descending weight is generally allowed to escape into an open vessel, and
therefore the pressure due to the descending weight is altogether wasted,
whereas according to the present Invention this pressure is utilized. In
carrying out my Invention I pump the water that is intended to set the
hydraulic lift in operation into an accumulator or receiver from which the
water at a suitable pressure is discharged into the cylinder of the hydraulic
apparatus in the usual manner for the purpose of raising the load required to
be elevated. When the platform of the lift is descending either with or
without a load, the weight of the load will exert a considerable pressure on
the water beneath it, and this pressure I employ to assist in working the
pumps which return the water from the lifting cylinder into the accumulator.
The precise arrangement of mechanism, whereby the object of the Invention
is effected, must depend upon the arrangement, construction, and disposition
of the lifting apparatus to which my improvements are intended to be applied.
I have therefore in the accompanying Drawing merely shewn in diagram a
mode of effecting the object and the arrangement of cocks or valves that
will be required for the purpose; a is the hydraulic cylinder in which works
the ram. a', whereby the lift bis raised in the ordinary manner. The
hydraulic cylinder a communicates by means of a pipe c (provided with a
stop-cock or valve d) with the accumulator or reservoir e, which may be
constructed in the ordinary manner. Water is pumped into this accu-
mulator by the pumps f, though the pipe g, which is provided with a stop-
cock or valve 9'. The water to supply the accumulator is drawn in the
first place from the open cistern or reservoir h, provided with a stop-cock
or valve h', and is forced by the pumps f into the accumulator, and
thereby raises the heavy weight e¹ therein. The pressure on the surface of
the water in the accumulator e will be that due to the heavy weight, say, for
example, five hundred pounds on the square inch. The lower end of the
bydraulic cylinder a also communicates by means of another pipe i provided
with a stop-cock or valve with the pumps f, so that the water from the
cylinder a may be pumped therefrom, and forced through the pipe g into the
accumulator e. By thus opening a communication between the cylinder a
and the pump f of the engine employed for charging the accumulator e, the
back pressure of the descending load on the lift b, and which I will suppose

page_text: to exert a pressure equal to about two hundred and fifty pounds on the
square inch, is caused to act upon the back of the piston in the pump f, and
thereby assist it in returning the water in the cylinder à to the accumulator e:
By this means a great economy of the engine power will be effected, the water
(which is under great pressure) being transferred without any important.loss
of that pressure from the cylinder a to the pumps f, thereby materially
assisting them to force the water into the accumulator e..
The several parts of the apparatus operate in the following manner :-
Supposing that the lift 6 has been raised to the required height. by allowing
water under pressure to pass from the accumulator e into the cylinder a under
the ram a¹ (instead of allowing the water to run into any open. vessel, and
thereby lose the pressure due to the descending weight, as is now generally
the case,) I close the cock or valve d on the pipe c, and open the cock or
valve on the pipe i so as to allow the water from the cylinder a at a pressure
of, say two hundred and fifty pounds on the square inch (due to the weight of
the lift b, and any load thereon) to enter the pump cylinders f at the back of
the pistons. From these pumps f the water will be forced along the pipe g
through the cock g' (which must have been previously opened) into the accu-
mulator. It will be obvious, then, that if a pressure of five, hundred pounds
on the square inch be required in the accumulator e, the engine which works
the pumps will only be required to exert a force sufficient to raise the pres-
sure in the pumps from two hundred and fifty to five hundred pounds on the
square inch, so as to give the required pressure in the accumulator. It will
be seen that in order to avoid complication in the Drawing, I have shewn
simple stop-cocks as the means of cutting off or regulating the communication
between the several parts of the hydraulic apparatus; I would observe, how-
ever, that any suitable construction of valve may be employed.
I would also observe that in some cases it will be found convenient to
arrange or combine two or more lifting cylinders in such a manner that one
may serve as the accumulator for the other, and vice versâ. The accumu-
lator e may in such case be dispensed with. The pipe in this arrangement
will not only act as a suction pipe as already described, but will sometimes
also serve as the forcing pipe. On the other hand the pipe 9 will not only
serve as the forcing pipe in the manner already explained, but will also act as
a suction pipe. The two pipes i and 9 must therefore communicate with a
four-way cock or any known suitable valve which is in connexion with the
pumps f, so that their action may be susceptible of being reversed by simply
turning or reversing the valve; a diagram of this arrangement is shewn at
Fig. 2.

page_text: Having now described my Invention of "Improvements in the Mode of
Working Hydraulic Lifts," and having explained the manner of carrying the
same into effect, I claim as the Invention secured to me by Letters Patent as
aforesaid, utilizing the pressure exerted by the descending weight on the
column of water beneath it for the purpose of assisting in working the pumps
which force the water under pressure into the accumulator or lifts for raising
other weights or loads.
In witness whereof, I, the said William Clay, have hereunto set my
hand and seal, the Twentieth day of July, in the year of our Lord
One thousand eight hundred and sixty-five.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
WILLIAM CLAY. (L.S.)