An Improved Hydraulic Press.
Year: 1890

page_text: Date of Application, 18th Dec.. 1890-Accepted, 24th Jan., 1891
COMPLETE SPECIFICATION.
An Improved Hydraulic Press.
We, FRANZ HORN and THEODOR KEETMAN both of Duisburg in the German
Empire, Directors of the Duisburger Maschinenbau Anstalt, 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:-
This invention relates to a hydraulic machine for pressing forgings, or stamping,
and with obvious modifications also adapted for shearing and other purposes.
The stamp or hammer is raised by steam acting upon the underside of a piston and
descends either by gravity alone or accelerated by steam pressure, the result of these
movements being that the stamp is merely brought down against the object to be
operated upon whilst the subsequent stamping is effected, without the employment of
an accumulator, by hydraulic pressure produced by an apparatus which we term a
pressure multiplier. This consists of one or more single or double acting pumps
worked through a hand lever from a steam cylinder in such a way that the piston may
be held in a given position and its speed and length of stroke regulated by the position
in which the hand lever is placed.
In the accompanying drawings
Figs. 1, 2, 3, are respectively side, back, and front views of a machine of this
invention.
Fig. 4 shews the hydraulic cylinder in section.
a is the stamp fixed in holder & attached to the lower end of hydraulic cylinder e
which in its up and down stroke is guided in frame d. e is the plunger suspended
from crosshead fixed on uprights g. is the steam cylinder to the bottom end of
the piston rod of which is fixed stamp holder and by it the hydraulic cylinder c
moved up and down. This action is effected by means of hand lever i in connection
through levers or rods with an unloaded piston slide valve shewn in Fig. 3 in a
position cutting off the admission of steam to the cylinder. Upon raising the slide
valve steam is admitted underneath piston k the exhaust steam passing out from the
upper part of the cylinder. Upon lowering the slide valve the space above the piston
comes into communication with that underneath it no steam exhausting or any fresh
steam passing in. By reason of the excess steam pressure on the upper larger piston
surface and the weight of the parts the piston descends and with it the stamp. In
this method of steam distribution there is a saving of steam as the bottom steam is
never wholly discharged but-according to the position of the piston k―more or less
expanded in the upper steam space. The plunger e is hollow the water for pressing
down the cylinder c passing in and out at the top of the plunger. Upon the down
stroke of cylinder c water from a reservoir passes past the valves of pressure pumps
through pipe m into the plunger and through this into the cylinder. All the valves
of the pumps work like suction valves.
The further supply of water to the plunger required for compression is obtained by
setting the pumps to work whereby pressure up to 400 atmospheres may be produced.
The ascent of the hydraulic cylinder takes place upon the discharge of water but as
all the pump valves act as check valves a valve such as n (Figs. 1, 2, 5, 7,) is
provided and is operated through hand lever i when this is moved to raise steam
piston k.
Figs. 5, 6, 7 are sectional views shewing the connection of pressure pipe m with the
suction or reservoir pipe p, past valve n. The pumps are worked from steam
cylinder q through hand lever r by displacing points. The effect of such displace-
ment, is on the one hand that the slide opens one of the admission ports bringing the
pumps to work and on the other hand that the slide by the movement of piston rod t
and of rod or differential lever u is brought back to close again, therefore a changed

page_text: position of the hand lever brings about a proportionatoly changed position of the
steam piston so that only such a movement of the slide valve is given as will effect a
travel of the piston or pressure from stamp a corresponding to the nature of the
work.
Figs. 8, 9, 10 are different views of a large forging press in which the arrangement
for compressing the water is not shewn but which may be readily applied thereto. In
this case the plunger e is held fixed, by four obliquely placed bars by which the strain
due to the hydraulic pressure is carried over to four vertical columns in a manner as
direct as practicable. In this construction of press the plunger packing at the top of
the hydraulic cylinder is not exposed to heat radiation also as the water for com-
pression is frequently changed the lower part of the hydraulic cylinder does not get
so highly heated as to clog in its guide. Here the hydraulic cylinder c and stamp a
is raised by means of two steam cylinders and there is not the difference of piston
area as in the previously described machine because in some cases the weight of the
parts is insufficient for the downstroke.
The pressure multiplier may be mounted on the framing of the machine or
arranged separate therefrom horizontally or vertically or single or double acting.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
1. A hydraulic machine for forging, shearing and other purposes in which the
stamp a is raised by one or more steam pistons, lowered by gravity alone or assisted
by steam and the pressing operation following thereon effected by hydraulic pressure
without the employment of an accumulator, the machine working in the manner
that:
a) Upon the ascent of the stamp, steam is admitted by means of hand lever i
and connections, into the space underneath the steam piston or pistons, the
steam in the upper cylinder space exhausted and at the same time through-the-
same hand lever and other connections a water valve is opened for the discharge
of water from the hydraulic cylinder.
b) Upon the downstroke of the stamp the steam previously used for lifting the
piston is by means-of-band-lever i-and-connections. admitted into the space
above the steam piston for the purpose of balancing the pressure underneath
and above the piston whilst water is drawn in through the water valve.
c) Upon the compressing operation and after closing the water valve the water
for compression-is by-means-of one or more single or double acting pressure
pumps fed into the hydraulic cylinder when each pressure of the stamp is
caused to correspond exactly with the oporation of a hand lever by means of
the intercalation of a differential lever u all substantially as described and
shewn.
2. In the machine referred to in claim 1 the suspension by its upper end of the
plunger either firmly fixed or so as to be capable of oscillation with the view of
utilising the hydraulic cylinder as a stamp or stamp carrier and of locating the plunger
packing as far as practicable from the action of the heat substantially as described ani
shewn.
3. In the machine referred to in claim 1 the suspension of the plunger in the
manner that the strain due to the hydraulic pressure is transferred from crosshead f
through tension bars to the supports of the machine so that the guide bars or guide
frame is relieved from strain substantially as described and shown.
100
1000
CAPITAINE & VON HERTLING,
89, Chancery Lane, London, W.C., Agents for the Applicants.