Improvements in Hydraulic Pressure Machines.
Year: 1895

page_text: Date of Application, 3rd Jan., 1895.
Complete Specification Left, 2nd Oct., 1895-Accepted, 28th Dec., 1895
PROVISIONAL SPECIFICATION.
Improvements in Hydraulic Pressure Machines.
I, JEAN MOLAS, of 247, High Road, Queen Anne's Avenue, South Tottenham,
in the County of Middlesex, Civil Engineer, do hereby declare the nature of this
invention to be as follows:-
My invention relates to multiple pistons or rams and it consists in the
combination of a number of pistons arranged in a cylinder and of a distributing
tube in such a manner that the area over which the pressure is distributed is varied
automatically so as to correspond with the variations in the load, thereby regulating
and limiting the consumption of the motive fluid, to the exact amount required for
the work to be performed to an equal height or travel.
In carrying out my invention in the case of a hydraulic press I provide the
apparatus with a series of pistons in the form of cylinders of gradually increasing
dimensions fitting and sliding over one another and adapted to actuate the ram, the
largest piston enclosing all the others having an effective area corresponding to
that of the ram. These pistons are arranged in a cylinder.
The
Through the pistons slides a tube serving to distribute the pressure upon the
particular piston of which the area corresponds to the power required.
distributing tube is actuated vertically or horizontally by a spindle valve to which
it is fixed, the said valve being in communication with the atmosphere and suitably
weighted in such a manner that, when the load is too great for the force of the
piston then in communication with the tube, the valve is moved by difference of
pressure or resistance of the load and at the same time moves the tube until it is in
communication with that piston which will be of the area required to raise the load,
all the other pistons above the opening of the distributer being kept at the top of
the apparatus (if the pressure be at the top) by the direct action of the pressure
fluid, and when the distributer rises under the action of a larger load, one or more
pistons will descend upon the ram of the apparatus, in order to increase the effective
area, and when the distributer falls by the diminution of the load, all the pistons
except the smallest one are kept raised by the pressure fluid introduced by the
distributer between this small piston and the one next following.
It will thus be seen that the movement of the spindle-valve in actuating the
distributer as above described causes the pistons to move automatically for
un"overing that piston the area of which will give the necessary power to balance
the weight of a given load and to raise it, whereby the quantity of water or other
fluid required is only the quantity necessary for effecting the stroke of the piston
acted on while the travel of the ram is always the same.
When the system is employed to actuate a crane, lift or other apparatus the same
results can be obtained by making the ram of a volume equal to the necessary
quantity of water to be displaced for the movement of the said crane, lift or other
apparatus to which the arrangement is connected, and, in order to insure and
complete this movement the centre of the ram of the apparatus is traversed by a
passage in communication with the pressure chamber, the said passage being closed
by a ball-valve contained in a chamber at the bottom in such a manner that when
the ram has nearly reached the end of its travel, the ball-valve projecting from its
chamber meets the bottom of the pressure chamber which raises it and thereby
furnishes a further slight pressure sufficient to complete the movement of the
machine.

page_text: The spindle-valve carries a pointer serving to indicate upon a scale the power
exerted upon the ram.
My multiple pistons or rams combined with their distributing tube as above
described can be employed in all kinds of engines and machinery requiring varying
degrees of power to be exerted upon pistons for 'the purpose set forth.
It is to be understood that other fluids than water can be employed with my
invention.
Dated this 2nd den of Tri100
Improvements in Hydraulic Pressure Machines.
I, JEAN MOLAS, of 247 High Road, Queen Anne's Avenue, South Tottenham,
in the County of Middlesex, Civil 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:-
My invention relates to the arrangement of multiple pistons or rams in a
hydraulic cylinder and their combination with a tubular supply valve in such
a manner that the area on which the hydraulic pressure acts is automatically varied
so as to correspond with the varying loads to be overcome, the expenditure of the
motive fluid being thus proportioned to the work which has to be performed
by it.
My invention may be applied in a regulating cylinder from which fluid under
pressure is sent to the working cylinder of a bydraulic lift, press, crane or the like,
the same fluid returning to the regulating cylinder after performing work; or it may
be applied in a direct acting cylinder in which the motive fluid acts directly on the
ram or plunger of the lift, press, or crane, as I shall describe referring to the
accompanying drawings.
Fig. 1 is a vertical section of a regulating cylinder for transmitting pressure to
a working cylinder, with means according to my invention for automatically suiting
the pressure and expenditure of motive fluid to the load on the piston or plunger
of the working cylinder.
Fig. 2 is a vertical section of a direct acting press or lift cylinder also arranged
according to my invention.
Fig. 3 is a part section of the apparatus shewn in Fig. 1 shewing a modification.
Referring first to Fig. 1 the regulating cylinder A which communicates by a
pipe or conduit B with the working cylinder of a hydraulic lift, press, crane or
the like, and which has the same capacity as that working cylinder, is fitted
with a piston C having a central boss D and several concentric annular plungers,
the upper ends of which are formed as pistons E F and G, each provided with
suitable external and internal packings. K is a central supply valve in the form
of a tube which is fitted to slide vertically and extends up through cavities
formed in the head of the cylinder; it terminates in a rod k of smaller diameter
which passes out through packing and has a crosshead and side rods to carry
weights L, in the form of segments, resting on shoulders of guides and so
arranged that as the rod k rises one after another weights is lifted, the load on k
being thus increased step by step as it ascends.
In the upper part of the tube K there is a lateral orifice M which is always
open to a cavity in the cylinder head, this cavity communicating by a pipe or
conduit N with the operating valve or valves for supplying high pressure water
and for discharging the water when the work is done.

page_text: The conduit N has two branches, n leading to a discharge valve, and n¹ leading
to a supply valve, both of these valves being of any known kind arranged to be
worked separately. In the branch to n¹ there is a valve S the stem of which
passes through packing and is externally connected to a tube s having within it
free to slide a rod T which is attached to the piston C and has a head t, the
length of the tubes being such that when the piston C approaches the lower
extreme of its stroke, the head t, acting on the lower end of the tube s, draws
it down and closes the valve S.
The apparatus operates as follows:
Assuming that a light load has to be raised by the piston or plunger of the
working cylinder, the high pressure water raises valve S and flowing through N
enters the tube K by the orifice M and acts on the area of the boss D causing the
piston C to descend and to force fluid by the conduit B into the working cylinder.
Should the pressure thus transmitted to the working cylinder be insufficient to
overcome the load, then as the piston C and its boss D cannot descend, the
pressure in and under the tube K increases, and the tube is forced upwards in
opposition to the weight I until the lower mouth of K is in such a position that
the service pressure acts on the larger area of E, as well as on D.
If the pressure
on this larger area be still insufficient to force down the piston C, the tube K is
still farther raised, lifting an added weight, and allowing the pressure to act also
on F, and it may be then on G, until the total area on which the pressure of the
water acts is such that the piston C is forced down, transmitting to the working
cylinder pressure sufficient to overcome the load thereon.
The movement of the lift or other machine worked by the pressure transmitted
from the regulating cylinder, may be arrested at any part of the stroke by closing
the supply valve in the branch n', and, when the stroke is completed, the valve S
is automatically closed.
On opening the discharge valve in the branch n allowing the water to escape
at N, the fluid, returning by B from the working cylinder, raises the piston C and
the pressure acting on the rod k being relieved, the tube K is pushed down by the
weight L. I prefer to form a lateral slit k¹ extending some distance down the
tube K, so as to give a larger area of passage for water as the tube rises, and has
to supply water to a larger space. When the fluid under the piston C is water, or
the same as the service fluid, which acts above the piston, I provide, as shewn in
Fig. 3, a passage Q with a check valve V, and on the bottom of the cylinder A a
projection a.
When the piston C reaches the bottom of the cylinder A. the valve V is slightly
lifted by a allowing fluid to flow by the passage from above the piston into the
space below it, so as to make up for any loss by leakage from the working cylinder
or its connections.
The concentric annular pistons as well as the main piston, are lubricated by oil
supplied to cavities O and the annular pistons are grooved for passage of oil.
except near their packings.
Referring now to Fig. 2 in which the same reference letters are employed to
denote parts corresponding to those in Fig. 1, instead of the service water being
applied to push down a piston C, it is applied to push up the table W of a press,
or lift acting as described with reference to Fig. 1 on a larger or smaller one of
the piston areas D, E, or F, according as the load on W is greater or less, this
being determined by the position of the sliding tube K. Instead of employing
weights successively lifted to resist the outward pressure acting on this tube, a
single weight L may be attached to a lever arm raised to successive positions by a
rack on the rod k acting on a toothed segment; w is a screw plug which can be
loosened to allow escape of air.
Instead of the number of concentric pistons shewn in the drawings, a greater or
less number may obviously be employed, according as it may be desired to have
smaller or greater gradations in the variations of the pressure and of the expenditure
of motive fluid.

page_text: Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, I declare that what I
claim is :-
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=
In a hydraulic cylinder, a number of concentric annular pistons presenting
successively increasing areas, in combination with a central supply tube automatically
moved by pressure of the motive fluid to such a position as to bring the fluid.to act
on a greater or less one of the piston areas, according as the main piston or plunger
of the cylinder is subject to a greater or less load, substantially as and for the
purpose set forth.
Dated this 2nd day of October 1895
ABEL & IMRAY,
Agents for the Applicant.