Improvements in and relating to Hydraulic Presses.
Year: 1898

page_text: Improvements in and relating to Hydraulic Presses.
I, HERMANN VON MITZLAFF, of 24B, Ringstrasse, Gross-Lichterfelde, near
Berlin, in the German Empire, Civil Engineer, do hereby declare the nature of
this invention to be as follows:-
Whenever, in the hydraulic presses heretofore employed, an alteration in the
travel or lift of the press-piston or plunger is required, it can only be effected in
a lengthy, tedious manner, which is quite impossible during the operation of the
press.
The present invention obviates these disadvantages. Any desired travel or lift
can be rapidly obtained by the movement of a single handle during the operation
of the press. For this purpose the plunger or ram of the press can be held, as
desired, in a higher or lower position by means of an auxiliary plunger remaining
under hydraulic pressure, and which passes, through a tightly-packed aperture in
the bottom of the press cylinder, into an auxiliary cylinder, for which purpose
so much water under pressure is led into this auxiliary cylinder by means of a
valve from a high-pressure water main, as is required to obtain the desired travel
or lift of the ram of the press.
In carrying my said invention into practice I preferably proceed as follows,
viz. On the press-cylinder is mounted a smaller cylinder which is in communica-
tion with the said press-cylinder through an aperture in the end thereof. Through
this aperture moves fluid-tight an auxiliary plunger whereby the higher or lower
position of the innermost limit of the travel or lift of the plunger or ram of
the press is determined. The auxiliary plunger is held in the desired position
by the hydraulic pressure on the surface thereof extending into the hollow space
of the cylinder. For this purpose a stout tube or pipe connects the auxiliary
cylinder with a hydraulic accumulator or pump. By means of a valve arranged
in the said pipe the flow of water under pressure into the interior of the auxiliary
cylinder beneath the plunger therein can be regulated as desired.
The entire height of lift of the plunger or ram of the press may be indicated
for example by h³, and to reduce this travel to h², so much water under pressure
is allowed to enter the auxiliary cylinder under the plunger therein from the
accumulator as to raise it through a distance h¹-h2-h³. By closing the valve
in the high-pressure water-main, the auxiliary plunger is prevented from passing
more than a certain distance into the auxiliary cylinder and thus the travel or
lift of the press-plunger or ram is reduced to h².
The valve in the high-pressure water-main is arranged in such a position, that
it is easily accessible to the workman in charge of the press. A suitable outlet-

page_text: passage and valve are also provided on the said auxiliary cylinder so as to enable
the water therein to escape and the lift or travel of the press-plunger or ram to
be again increased as desired.
Dated this 31st day of January 1898.
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.
Improvements in and relating to Hydraulic Presses.
I, HERMANN VON MITZLAFF, of 24B, Ringstrasse, Gross-Lichterfelde, near
Berlin, in the German Empire, 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:-
―
Whenever, in the hydraulic presses heretofore employed, an alteration in the
travel or lift of the press-piston or plunger is required, it can only be effected by
a lengthy, tedious operation which is quite impossible during the working of the
press.
The present invention obviates these disadvantages and enables any desired
travel or lift to be rapidly obtained by the movement of a single handle, during
the working of the press. For this purpose the plunger or ram of the press is
held, as desired, in a higher or lower position by means of an auxiliary plunger
remaining under hydraulic pressure, and which passes, through a tightly-packed
aperture in the bottom of the press cylinder, into an auxiliary cylinder, so much
water under pressure being admitted into this auxiliary cylinder by means of a
valve from a high-pressure water-main, as is required to obtain the desired travel
or lift of the ram of the press.
The drawing shows the arrangement in vertical section.
On the press-cylinder P is mounted a smaller cylinder Q, which is in com-
munication with the said press-cylinder through an aperture in the end thereof.
Through this aperture moves fluid-tight an auxiliary plunger B whereby the
higher or lower position of the innermost limit of the travel or lift of the plunger
or ram K of the press is determined. The auxiliary plunger B is held in the
desired position by hydraulic pressure on the surface thereof extending into the
hollow space of the cylinder Q. For this purpose a stout tube or pipe e connects
the auxiliary cylinder Q with a hydraulic accumulator or pump. By means of
a valve V arranged in the pipe e, the flow of water under pressure into the interior
of the auxiliary cylinder beneath the plunger B can be regulated as desired.
The entire height of lift of the plunger or ram K of the press may be indicated
for example by h, and to reduce this travel to h², so much water under pressure
is allowed to enter the auxiliary cylinder Q under the plunger B from the
accumulator as to raise it through a distance h¹-h²=h³. By closing the valve V
the auxiliary plunger B is prevented from passing more than a certain distance
into the auxiliary cylinder and thus the travel or lift of the press-plunger or
ram K is reduced to h².
The valve is arranged in such a position, in the pipe e that it is easily
accessible to the workman in charge of the press. A suitable outlet-passage and
valve are also provided on the said auxiliary cylinder so as to enable the water
therein to escape and the lift or travel of the press-plunger or ram to be again
increased as desired.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
A device for adjusting or varying the lift in hydraulic presses, wherein the
plunger or ram of the press is held, as desired, in a higher or lower position by
means of a tightly-packed plunger kept under hydraulic pressure and extending
through the bottom of the press-cylinder into an auxiliary cylinder, into which
so much water under pressure is admitted from a high-pressure water-main by
means of a valve, as is required for the desired lift of the ram or plunger of the
press.
Dated the 26th day of September 1898
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.