Improvements in Hydraulic Presses for Forging and Analogous Purposes.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Hydraulic Presses for Forging and Analogous
Purposes.
I, JOHN FIELDING, of Upton Saint Leonards, in the County of Gloucester,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved system of operating the valves of hydraulic
presses and the pressure generating apparatus for working the same.
When such presses are used for forging it is desireable whilst the press ram may
have sufficient stroke to allow ample clearance between the tools for the free
manipulation of the forging, that the use of pressure water should be strictly
limited to the actual impression made upon it, and my invention relates to an
improved method of operating the working valves of such presses, and their
pressure generating apparatus, whereby the admission of high pressure water
to the press cylinder is delayed until the moment that the press tool touches the
forging; when, as a consequence of such contact, it is automatically admitted,
it being also impossible for a careless or unskilful workman to cause the too
early admission, and consequent waste of pressure water.
Although forging is more particularly referred to, it is to be understood that
my invention may be adapted to presses, or machines, for riveting, punching,
and other operations.
My invention applies equally to presses worked by means of pumps and
accumulator, direct pumps without accumulator, accumulator with intensifier, or
direct intensifier whereby the high hydraulic pressure is produced by means of
steam, air, or a lower hydraulic pressure.
In carrying my invention into practice I may employ two methods of automatic
valve working, either singly or in combination, according to circumstances.
For a vertically downward acting press where the weight of the moving parts
is sufficient to ensure a quick downward movement through the idle part of
the stroke, may cause the working valves to be operated by the variations of
pressure in a hydraulic cylinder which gives the lifting or return stroke of the
press, this cylinder is controlled by a hand worked valve which admits water
for the lifting stroke, or permits its escape in order to lower the press ram and
tool down upon the forging.
Three different conditions of pressure are produced in the lifting cylinder,
these variations being utilized for the purpose of actuating the main inlet and
outlet valves of the press, for which purpose pipes are fitted connecting the lifting
cylinder with suitable cylinder or cylinders which operate the working valves.
Thus, when the press ram is being raised, there will be full pressure in the
lifting cylinders, which are so arranged that the main exhaust valve of press
is opened at the same time that the supply of pressure water is shut off either by
shutting the inlet valve where the press is worked from an accumulator, or by
shutting off the steam where a direct steam pumping engine is used.

page_text: When the press ram is being lowered through the idle part of its stroke, the
weight of the falling parts and the resistance to the escape of water from the lifting
cylinder produces a certain reduced pressure in the latter, and the valve working
rams are suitably proportioned that this reduced pressure is sufficient to hold the
exhaust valve open so that the cylinder may be kept filled with low pressure
water; the pressure inlet, or steam valve being shut; but the moment that the
pressing tool rests upon the forging the pressure in the lifting cylinder dis-
appears, or is reduced to a minimum, causing the exhaust valve to be closed
and pressure to be admitted either by opening an inlet valve, or by turning steam
on to pumping engine.
Where the moving parts are too light, or where they act in a direction other
than vertically downward the action of gravity may be replaced by that of a
supplementary cylinder and ram, which may be exposed to constant pressure,
the working of the main valves being still effected by the variations of pressure
in the lifting cylinder in the manner already described, or in lieu of this the
lifting movement may be made by constant pressure acting upon the lifting ram,
the manipulation of the press being effected by a hand worked valve, which
admits pressure water to be aforesaid supplementary cylinder to make the idle
part of the downward stroke, or exhausts it to make the upward stroke.
When this arrangement is adopted I connect the valve working cylinders
to the supplementary cylinder, the action being as follows:-
When pressure is first admitted to the supplementary cylinder to run the press
ram through the idle part of its stroke, there is very little rise of pressure, because
the resistance offered is only that due to the friction of packings, but as soon
as the tool comes in contact with the forging the motion is arrested and the
pressure in the supplementary cylinder quickly rises to the maximum, this
pressure acts upon the valve operating rams to close exhaust valve, and to
admit pressure to the main cylinder, or to open the steam stop valve on pumping
engine to set the latter in motion delivering into the main cylinders, or, in a
corresponding manner, the valve working rams may operate the valve of a direct
pressure intensifier whether worked by steam, air, or hydraulic pressure.
When pressure is taken off the supplementary cylinder the reverse action of
the various valves takes place.
According to another arrangement, the use of the two above described methods
may be combined in the following manner.
The main inlet and outlet valves of the press may be operated by connection
with the lifting cylinders in the manner first described, pressure being supplied
to operate the lifting cylinders, and the main cylinder from an accumulator:
an intensified pressure is also supplied to the main cylinder by an intensifier
operated either by steam, air, or hydraulic pressure.
The valve which controls the supply of working fluid to the large cylinder of
the intensifier is operated automatically by a valve working cylinder and ram,
which is connected by an open pipe with the main cylinder of press.
A non return valve is placed in the pipe leading from the accumulator to
the press, the connection of the high pressure cylinder of the intensifier to the
press being made between the non-return valve, and the main valve of press.
There is no valve between these two the connection being quite free.
The mode of working is as follows:
The attendant operates the valve which controls the pressure and exhaust of
the lifting cylinders, the main valve acting in the manner already described
admitting pressure water from the accumulator; as soon
compressed to such an extent as is possible with the accumulator pressure, the
as the forging is
latter acting upon the cylinder, which operates the valve of the intensifier; causes
the latter to be automatically brought into action, intensifying the pressure
in the press cylinder to complete the compression of the forging.
In a somewhat similar combination arrangement, two steam intensifiers may

page_text: be used, one to give a low pressure, the other a high pressure, so that the forging
may first be compressed as far as possible by the low pressure before the applica-
tion of the high pressure.
In such an arrangement the steam valve of the low pressure intensifier is
worked by a hydraulic cylinder and ram actuated by pressure from the lifting
cylinders, whilst that of the high pressure is worked by pressure from the main
cylinder of press, this system of two intensifiers greatly economizes the consump-
tion of steam.
The lifting movement of the press may be worked from a pump and accumu-
lator, but the latter is not drawn upon to supply the main cylinder of press.
These combined arrangements are specially applicable in cases where pumps
and accumulator which, whilst not of sufficient capacity, to work the press
entirely may be large enough to supply the lifting cylinders.
I employ preferably piston valves to control the steam to the intensifier cylinder,
and I make them with separate steam and exhaust ports to the cylinder the steam
port communicates direct with the main body of cylinder, whilst the exhaust
port leads to a central opening which is closed by a projection upon the piston
when the latter approaches the end of its exhaust stroke, thus steam is shut up
in the main body of cylinder to form a cushion for the piston.
Dated this 25th day of February 1898.
Improvements in Hydraulic Presses for Forging and Analogous
Purposes.
I, JOHN FIELDING, of Upton Saint Leonards, in the County of Gloucester,
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 an improved system of operating the valves of hydraulic
presses and the pressure generating apparatus for working the same.
When such presses are used for forging it is desireable, whilst the press ram may
have sufficient stroke to allow ample clearance between the tools for the free
manipulation of the forging, that the use of pressure water should be strictly
limited to the actual impression made upon it, and my invention relates to an
improved method of operating the working valves of such presses, and their
pressure generating apparatus, whereby the admission of high pressure water
to the press cylinder is delayed until the moment that the press tool touches the
forging; when, as a consequence of such contact, it is automatically admitted,
it being also impossible for a careless or unskilled workman to cause the too
early admission, and consequent waste of pressure water.
Although forging is more particularly referred to, it is to be understood that
my invention may be adapted to presses, or machines, for rivetting, punching,
and other operations.
0
My invention applies equally to presses worked by means of pump and
accumulator, direct pumps without accumulator, accumulator with intensifier, or
direct intensifier whereby the high pressure is produced by means of steam, air,
or a lower hydraulic pressure.
In carrying my invention into practice I may employ two methods of automatic
valve working, either singly or in combination, according to circumstances.

page_text: For a vertically downward acting press where the weight of the moving parts
is sufficient to ensure a quick downward movement through the idle part of
the stroke, I may cause the working valves to be operated by the variation of
pressure in a hydraulic cylinder which gives the lifting or return stroke of the
press, this cylinder is controlled by a hand worked valve which admits water
for the lifting stroke, or permits its escape in order to lower the press ram and
tool down upon the forging.
Three different conditions of pressure are produced in the lifting cylinder,
these variations being utilized for the purpose of actuating the main inlet and
outlet valves of the press, for which purpose pipes are fitted connecting the lifting
cylinder with suitable cylinder or cylinders which operate the working valves.
Thus, when the press ram is being raised, there will be full pressure in the
lifting cylinders, which are so arranged that the main exhaust valve of press
is opened at the same time that the supply of pressure water is shut off either by
shutting the inlet valve where the press is worked from an accumulator, or by
shutting off the steam where a direct steam pumping engine is used.
When the press ram is being lowered through the idle part of its stroke, the
weight of the falling parts and the resistance to the escape of water from the lifting
cylinder produces a certain reduced pressure in the latter, and the valve working
rams are suitably proportioned that this reduced pressure is sufficient to hold the
exhaust valve open so that the cylinder may be kept filled with low pressure
water; the pressure inlet, or steam valve being shut; but the moment that the
pressing tool rests upon the forging the pressure in the lifting cylinder dis-
appears, or is reduced to a minimum, causing the exhaust valve to be closed
and pressure to be admitted either by opening an inlet valve, or by turning steam
on to pumping engines.
Where the moving parts are too light, or where they act in a direction other
than vertically downward the action of gravity may be replaced by that of a
supplementary cylinder and ram, which may be exposed to constant pressure,
the working of the main valves being still effected by the variations of pressure
in the lifting cylinder in the manner already described, or lieu of this the
lifting movement may be made by constant pressure acting upon the lifting ram,
the manipulation of the press being effected by a hand worked valve, which
admits pressure to the aforesaid supplementary cylinder to make the idle
part of the downward stroke, or exhausts it to make the upward stroke.
When this arrangement is adopted I connect the valve working cylinders
to the supplementary cylinder, the action being as follows:-
When pressure is first admitted to the supplementary cylinder to run the press
ram through the idle part of its stroke, there is very little rise of pressure, because
the resistance offered is only that due to the friction of packings, but as soon
as the tool comes in contact with the forging the motion is arrested and the
pressure in the supplementary cylinder quickly rises to the maximum, this
pressure acts upon the valve operating rams to close exhaust valve, and to
admit pressure to the main cylinder, or to open the steam stop valve on pumping
engines to set the latter in motion delivering into the main cylinders, or, in a
corresponding manner, the valve working rams may operate the valve of a direct
pressure intensifier whether worked by steam, air, or hydraulic pressure.
When pressure is taken off the supplementary cylinder the reverse action of
the various valves takes place.
According to another arrangement, the use of the two above described methods
may be combined in the following manner: —
The main inlet and outlet valves of the press may be operated by connection
with the lifting cylinders in the manner first described, pressure being supplied
to operate the lifting cylinders, and the main cylinder from an accumulator:
an intensified pressure is also applied to the main cylinder by an intensifier
operated either by steam, air, or hydraulic pressure.
The valve which controls the supply of working fluid to the large cylinder of

page_text: the intensifier is operated automatically by a valve working cylinder and ram,
which is connected by an open pipe with the main cylinder of press.
A non return valve is placed in the pipe leading from the accumulator (o
the press, the connection of the high pressure cylinder of the intensifier to the
press being made between the non-return valve, and the main valve of press.
There is no valve between these two the connection being quite free.
The mode of working is as follows:
The attendant operates the valve which controls the pressure and exhaust of
the lifting cylinders, the main valve acting in the manner already described
admitting pressure water from the accumulator; as soon as the forging is
compressed to such an extent as is possible with the accumulator pressure, the
latter acting upon the cylinders, which operates the valve of the intensifier, causes
the latter to be automatically brought into action, intensifying the pressure
in the press cylinder to complete the compression of the forging.
In a somewhat similar combination arrangement, two steam intensifiers may
be used, one to give a low pressure, the other a high pressure, so that the forging
may be first compressed as far as possible by the low pressure before the applica-
tion of the high pressure.
In such an arrangement the steam valve of the low pressure intensifier is
worked by a hydraulic cylinder and ram actuated by pressure from the lifting
cylinders, whilst that of the high pressure is worked by pressure from the main
cylinder of press, this system of two intensifiers greatly economises the consump-
tion of steam.
The lifting movement of the press may be worked from a pump and accumu-
lator, but the latter is not drawn upon to supply the main cylinder of press.
These combined arrangements are specially applicable in cases where pumps
and accumulator which, whilst not of sufficient capacity, to work the press
entirely may be large enough to supply the lifting cylinders.
I employ preferably piston valves to control the steam to the intensifier cylinder,
and I make them with separate steam and exhaust ports to the cylinder the steam
port communicates direct with the main body of cylinder, whilst the exhaust
port leads to a central opening which is closed by a projection upon the piston
when the latter approaches the end of its exhaust stroke thus steam is shut up
in the main body of cylinder to form a cushion for the piston.
DESCRIPTION OF THE DRAWINGS.
In the accompanying drawings Sheets 1 & 2 shew a forging press 1 the main
ram of which is operated by means of a steam intensifier 2 whilst the lifting
cylinders 33 are worked by pressure from an accumulator (not shewn) controlled
by a hand worked valve 4. In this valve 5 is the pressure supply from accumu-
lator 6, the branch leading to the lifting cylinders and 7 the exhaust branch.
8 is a mitre seated valve which serves alternately for filling the press cylinder
from an overhead tank whilst the ram is falling through the idle or clearance
part of its stroke, and as an exhaust valve during the upward movement, 9 is a
hydraulic cylinder, connected by a pipe 10 to the lifting cylinders 33; its
ram 11 serving to lift the valve 8 from its seat when pressure is admitted to the
lifting cylinders 3 3, and to hold it up so long as pressure remains therein, whether
the pressure be that of the accumulator or only that due to the weight of the
falling parts of press. The ram 11 is forced back when pressure is taken off
by the springs 41.
12 is another mitre seated valve which controls admission of pressure water
from the hydraulic cylinder 13 of the steam intensifier 2. The valve 12 is
partially balanced by the spindles passing through the glands 14, 15, above and
below the valve seat, the lower gland 15 being slightly smaller than the valve
seat, and the upper gland, so that when pressure is produced in the chamber 16
communicating by the pipe 17 with the cylinder 13, the valve tends to open the
chamber 18 leading to the press cylinder by pipe 19 the valve 12 is held down

page_text: upon its seat by a hydraulic piston 20, the cylinder of which is connected to the
lifting cylinders 33 by the pipe 21 and also by a spring 22 upon the lower end
of the valve spindle.
23 is the exhaust and filling pipe leading away to an overhead tank or low
pressure reservoir.
Referring now to the steam intensifier 2 which is shewn in section, 24 is the
steam cylinder, 25 the piston, 26 the piston rod which also acts as a hydraulic
ram working in the cylinder 13. The steam cylinder is fitted with cover 27
having the usual stuffing box and gland.
28 is a piston valve chamber in which works the piston valve 29, 30 & 31 are
the steam and exhaust branches, 32 the steam inlet port to cylinder and 33 the
exhaust port into which it communicates by way of a central chamber 34. A
projecting boss 25 closes up this central chamber slightly before the piston
reaches the bottom of the cylinder causing steam to be bottled up so as to form
a cushion between the lower side of piston and the cylinder bottom.
36 & 37 are respectively a differential hydraulic cylinder and ram, the former
communicating by a pipe 38 with the lifting cylinders 3, 3, of the forging press,
the area of the differential ram is suitably proportioned in relation to the area
of the steam piston valve, and the relative steam and hydraulic pressures so that
when the press is making its lifting or upward stroke, the piston valve will be
raised, opening the exhaust port 33, but as soon as the pressure is taken off the
cylinders 3, 3, and before the tool touches the forging the steam acting upon
the upper surface of the piston valve 29 will overcome the hydraulic pressure,
causing the valve 29 to descend, closing the exhaust port 33 and opening the
steam port 32. The main piston 25 being forced upwards producing pressure
in the cylinder 13, pipe 17 and chamber 16 the valve 12 however is retained
upon its seat by the pressure upon the piston 20 which is so proportioned that
the reduced pressure in cylinders 3, 3, due to the weight of the falling parts of
is still sufficient to prevent the valve 12 from leaving its seat.
So soon
however as the press tool touches the forging and the pressure in cylinders 3, 3,
disappears, the valve 12 opens admitting pressure from the cylinder 13, where
it has been stored in readiness, very much in the manner of an accumulator.
Pressure water from an accumulator is conveyed to the cylinder 13 by a
pipe 39, and non return valve 40.
The piston valve 29 is preferably made without piston rings, but is provided
with mitre seatings upon its upper and lower faces, these seatings bear upon corre-
sponding shoulders in the valve chamber so as to shut alternately the steam inlet
and exhaust outlet.
Sheet 3 Fig. 1 shews an arrangement more suitable for a press worked by pumps
and accumulator in which the moving parts are light, or where the press acts in
other than a downward vertical direction. In this case the lifting cylinder 1
is made double acting, constant pressure acting upon the smaller area of piston 2
to effect the return of the main ram 3 whilst the other side of the piston, of
greater area, is controlled by a hand worked valve 4 of which the pipe 5 is the
pressure inlet, 6 the exhaust and 7 the branch leading to the cylinder 1, 8 is the
constant pressure supply to the smaller area of the piston 2, 9 is the main valve
box bolted to the inlet of main cylinder. The main valve 10 is of the mitre
type, working between the sliding seatings 11 & 12, which respectively communi-
cate with the pressure and exhaust pipes. 13 being the pressure inlet leading
from the accumulator, 14 the exhaust pipe leading to a tank 15, which should
be as close as convenient.
Stop collars upon the valve seats 11 & 12 and shoulders in the valve chamber 9,
limit the movement of the two seatings. When the valve 10 is in mid position
both seatings are closed.
A spring 16 serves to keep the exhaust seating towards the face of valve, the
inlet seating 11 being forced towards the valve by hydraulic pressure acting upon

page_text: the annular area due to the difference between the diameters of the packing
leather 17 and the internal diameter of the seating.
The valve 10 is fitted with a piston 18 working in a differential cylinder 19
at one end of the valve chamber 9, the effective area of this cylinder being that
due to the difference between the diameter of the piston 18 and the boss 20, an
adjustable spring 21 serves to regulate the action of the valve within certain
limits in order to provide for any variation in hydraulic pressure, stiffness of
packing, or other irregularities 22 is a pipe connected with the larger area of
cylinder 1.
The action is as follows viz.:-
Assuming the press ram to be at the top of its stroke pressure acting upon the
smaller area of the lifting piston 2, also on the inlet chamber 13 of the main
valve box 9 where it acts upon the differential area due to the difference between
the diameter of the piston 18 and the packing leather 17, the pressure upon this
differential area causes the valve 10 to move towards the left hand, closing the
inlet valve, and opening the exhaust.
Now when by working the valve 4 pressure is admitted to the larger area of
piston 2, the press ram will be lowered, and water will be drawn into the main
cylinder through the exhaust pipe 14 but as soon as the press tool touches the
forging the extra resistance offered produces an immediate increase of pressure
in the larger area of piston 2 and this being communicated by the pipe 22 to
the differential cylinder 18 drives the valve 10 towards the right hand, until it
first closes the exhaust and then as soon as the seating 11 comes against its stop,
opens the pressure valve admitting pressure to the main cylinder to produce the
desired impression on the forging.
As soon as the valve 4 is again reversed to exhaust the larger area of the
piston 2 the main valve again returns to the left hand closing pressure and
opening the exhaust valve.
4 is the
The valve 9 is shewn to a larger scale in Fig. 2 Sheet 3. Sheet 4 shews an
arrangement of a press of which the main and lifting cylinders are worked from
an accumulator, but with provision for obtaining an intensified pressure in the
main cylinders by means of an intensifier which may be worked either by steam
or hydraulic pressure; as shewn in the drawing the intensifier is worked by steam.
The press
is fitted with two lifting cylinders which are of the piston type,
the pistons working in the cylinders 2, 2, and being connected to the press cross-
head 3 by rods working through stuffing boxes in the usual manner.
working valve which controls the lifting cylinders by pipes to 6, 6.
A steam intensifier, generally similar to that shewn in Sheet 1 is indicated
at 7, 8 is a non return valve through which hydraulic pressure is supplied to the
cylinder 9 from the accumulator, 10 is the pipe connecting the cylinder 9 to the
press main cylinder, 11 is the main valve of press, which may be of the type
described in the Specification of my Patent No. 3144 of 1898, but arranged to be
operated by hydraulic pressure. In this valve 12 is the pressure inlet chamber
connected to pipe 10, 13 is the exhaust outlet and 14 the connection to the main
cylinder of press, 15 is a piston at one end of the valve ram exposed to the
pressure in the chamber 12 by means of a passage through the centre of valve
ram communicating with chamber 12.
16 is a piston at the other end of the valve, of larger area, the cylinder of
which is connected by a pipe 17 with the pipes leading to the lifting cylinders 2, 2.
The valve 11 is shewn to a larger scale in Fig. 2 Sheet 3. When the main
cylinder of press is supplied with pressure water by a pumping engine direct
without an accumulator I fit to the engine a hydraulically controlled steam stop
valve similar to that shewn by Fig. 3 on Sheet 4, in which 1 is the steam valve,
2 a hydraulic cylinder with ram 3.
The cylinder 2 is connected by a pipe 4 with the lifting cylinders of press
in the manner already described in reference to the hydraulic cylinder 36 on
Sheet 1.

page_text: Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed I declare that what
I claim is:
1. In a hydraulic press for forging and analogous purposes, utilizing the
variations of pressure in the lifting or return cylinders for the purpose of operating
the main inlet and outlet valves, so that during the idle part of the press stroke
the exhaust valve is held open in order to admit low pressure water to the press
cylinder, and as soon as the press tool touches the work, to automatically close
the exhaust valve and open the pressure inlet valve to enable the press to com-
plete its stroke, substantially as described.
2. In a hydraulic press for forging and analogous purposes utilizing the
variations of pressure in an auxiliary cylinder, which may also act as a lifting
cylinder, for the purpose of operating the main inlet and outlet valves, so that
during the idle part of the press stroke the exhaust valve is held open in order to
admit the low pressure water to the press cylinder, and as soon as the press tool
touches the work, to automatically close the exhaust valve and open the pressure
inlet valve to enable the press to complete its stroke, substantially as described.
3. In pressure generating apparatus, such as a pumping engine, or steam or
hydraulic intensifier used in connection with hydraulic presses for forging and
analogous purposes utilizing the variations of pressure in the lifting cylinders
or main cylinder of press for the purpose of operating the valves which control
the said pressure generating apparatus in such a manner that the said generating
apparatus only comes into action at about the time the press tool touches the
work, substantially as described.
Dated this 1st Jan of Threamihan 1000