IMPROVEMENTS IN WORKING PRESSES AND OTHER HYDRAULIC MACHINES
Year: 1859

page_text: LETTERS PATENT to George Ashcroft, of Cardiff, in the County of
Glamorgan, Engineer, for the Invention of "IMPROVEMENTS IN WORKING
PRESSES AND OTHER HYDRAULIC MACHINES."
Sealed the 13th October 1859, and dated the 15th April 1859.
PROVISIONAL SPECIFICATION left by the said George Ashcroft at the
Office of the Commissioners of Patents, with his Petition, on the
15th April 1859.
I, GEORGE ASHCROFT, of Cardiff, in the County of Glamorgan, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
WORKING PRESSES AND OTHER HYDRAULIC MACHINES," to be as follows:-
My Invention consists in working presses and other machines partly by the
power derived from a power accumulator or reservoir, and then by suitable
force pumps. The Invention also consists of an improved method of returning
the pressing rams back into the cylinders after they have exerted the required
pressure by means of the power exerted by the power accumulator or reservoir.
The operation is as follows:-Supposing artificial fuel to be the material to be
pressed, it is placed in moulds with, say, a pair of rams, communication
between the power reservoir and the ram chambers is first established, and the
rams rise, descend, or advance, exerting the pressure derived from the

page_text: reservoir, then by means of a valve arrangement communication with the
pumps is opened, and pressure is continued upon the rams to the degree
required, which is regulated by a relief valve, or other suitable arrangement.
As soon as their maximum pressure has been attained, the communication with
the pumps is cut off, and the pressure exerted by the reservoir of power
takes effect upon the supplementary ram chambers or rams in such a way as
to cause the pressing rams to return to their original position. When the
pressing rams are thus fully returned they are again ready to act as before
explained. The valves may be worked by the action of the machinery, or
they may be worked by hand, or partly by both means.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Ashcroft in the Great Seal Patent Office on the
15th October 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
ASHCROFT, of Cardiff, in the County of Glamorgan, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifteenth day of April, in the year of our
Lord One thousand eight hundred and fifty-nine, in the twenty-second
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said George Ashcroft, Her special licence that I, the
said George Ashcroft, my executors, administrators, and assigns, or such
others as I, the said George Ashcroft, 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 "IMPROVEMENTS IN WORKING PRESSES AND OTHER HYDRAULIC
MACHINES," upon the condition (amongst others) that I, the said George
Ashcroft, my executors or administrators, 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 George Ashcroft do hereby declare
the nature of my said Invention, and in what manner the same is to be

page_text: performed, to be particularly described and ascertained in and by the fol-
lowing statement thereof, that is to say :---
My Invention relates to certain apparatus to be used in connection with
hydraulic presses and other similar machines for the purpose of increasing the
speed at which such machines can be worked when applied to the manufacture
of artificial fuel or other operations where great speed is of importance.
The first part of my Invention consists in the combination of an accumulator
with an ordinary force pump in such manner as to ensure the greatest advantage
from the force acquired. For this purpose I employ either a common ram
working in a cylinder, and loaded to any required weight, so as to maintain
a constant pressure, or else I employ a ram in connection with a steam
cylinder.
I now proceed to describe the manner in which my said Invention may be
carried into effect.
I take any hydraulic press or presses, and then proceed to erect an accumu-
lator in such a position that a pipe may be made to communicate from the
cylinder in which the ram of the accumulator works, to the cylinder of the
hydraulic press; in this pipe is fitted a stop valve opening into a branch pipe,
which leads to a powerful force pump; so so long as the stop valve is down, no
water can pass from the force pump along the branch pipe into the cylinder of
the hydraulic press, but the valve is so arranged that water can pass from the
accumulator to the cylinder of the press, and when the stop valve is up com-
munication is cut off between the accumulator and cylinder of the press.
Now this valve may be made to open at any pressure, either by means of a
spring or of a lever and weight. The advantage resulting from this arrange-
ment is that a low pressure may be maintained in the accumulator which will
give sufficient pressure to commence the operation of pressing fuel or other
material, and when all the pressure has been exerted which the accumulator
will yield, the stop valve shutting off communication between the accumulator
and press opens communication between the force pump and press; the force
pump then in a few strokes completes the operation.
The second part of my Invention relates to a mode of causing the rams of
hydraulic presses to return into the cylinders with greater speed than those in
general use. To effect this, I construct one or two cylinders with glands at
their mouths in which plungers or rams are capable of working freely and yet
water-tight; I then connect the said cylinder or cylinders by means of a pipe
to the accumulator. It follows that the water which flows into the cylinders
from the accumulator will be subject to whatever pressure the load on the ram
of the accumulator is subject, and it will exert the same pressure, proportionate

page_text: to their area, upon the rams or plungers of the cylinders now described. I fix
these cylinders with their rams in such position that the force exerted by them,
as before described, presses directly opposite to the ram of the hydraulic press
or other machine; it follows that when the pressure exerted upon the ram is
made to cease, the pressure upon the. rams. of my subsidiary cylinder (which
rams being in constant communication with the accumulator are always
exerting their pressure) will cease the ram at once to return to its former
position.
And having now described the nature of my said .Invention, and in what
manner the same is to be performed, I. declare that I claim,―
First, the working of presses and other hydraulic machines by the employ-
ment of an accumulator combined with a force pump or force pumps,
substantially in manner herein-before described.
And, second, the method herein-before described of causing the pressing
rams to return back into the cylinders after having exerted their pressure.
In witness whereof I, the said George Ashcroft, have hereunto set my
hand and seal, this Twelfth day of October, One thousand eight
hundred and fifty-nine.
Witness to the signature of the said
Geo. Ashcroft,
W. F. GAMMAN.
GEORGE ASHCROFT. (L.S.)