Improvements in and relating to Hydraulic Presses having Telescopic Pistons.
Year: 1891

page_text: Date of Application, 6th June, 1891
Complete Specification Left, 11th Feb., 1892-Accepted, 12th Mar., 1892
PROVISIONAL SPECIFICATION.
[Communicated from abroad by DIE ACTIEN GESELLSCHAFT GRUSONWERK, of
Magdeburg, Buckau, in the Empire of Germany.]
Improvements in and relating to Hydraulic Presses having
Telescopic Pistons.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co. Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby
declare the nature of this invention to be as follows:-
it
This invention relates to apparatus for effecting the return movement of
telescopic piston in a hydraulic press, after the outward stroke has been completed,
by the fluid under pressure.
In presses having a single or simple piston, the return movement can be provided
for, as is well-known, by making the piston, not in the form of a plunger, but as a
double-acting piston, and conducting the fluid under pressure (after the completion
of the outward stroke and after the opening of the exhaust-valve of the cylinder)
into the annular space in front of the said piston.
The problem becomes more difficult if, by reason of local conditions, it is necessary
to employ a telescopic piston.
The present invention solves this problem by the construction of the several
parts or sections of the telescopic piston as double-acting pistons, and the provision
of suitable means whereby the annular spaces in front of the several sections may
be connected by a common pipe with the force-pumps, the accumulator or the
pressure-main on the one hand, and with the exhaust reservoir or main on the
other hand.
In carrying the said invention into practice, the press-cylinder is made in one
piece with a second smaller or auxiliary cylinder, arranged parallel therewith,
the fluid under pressure is conducted to the press-cylinder through a cock or other
suitable distributing device. In the said press-cylinder slides a piston which is
bored out cylindrically; in the bore of this piston slides a smaller piston which is
also bored out and in which slides a still smaller piston, which may be solid if the
telescopic piston is formed of only three parts or sections.
The annular space in front of the largest piston communicates, through a channel
at the front end of the press-cylinder, with the auxiliary cylinder, which, in its
turn, is in communication with the said cock by means of a suitable pipe. The
annular space in front of the second piston communicates, through a channel in the
wall of the largest piston at the front end of the same and through a suitable pipe.
with the auxiliary cylinder. The last named pipe extends into the auxiliary
cylinder and is made tight therein, and is firmly connected with the largest piston
so that it must participate in the movement of the latter. In like manner, the
annular space in front of the smallest piston is in communication with the auxiliary
cylinder through a suitable channel and through a pipe which extends through
and is made tight in the head of the pipe attached to the largest piston. The
press-cylinder, moreover, communicates with one of the four ways of the aforesaid
cock through another pipe.
The transverse section of the annular space in front of the second pisten is some-
what larger than the transverse section of the pipe connecting the same with the
auxiliary cylinder, and the transverse section of the space in front of the smallest
piston is somewhat larger than the transverse section of the pipe connecting this
space with the said cylinder. The capacity of the fluid space in the said auxiliary
cylinder and in the annular spaces will, therefore, be greatest when the telescopic
piston is completely extended, and smallest when the said telescopic piston is

page_text: completely pushed in or contracted. The difference between the greatest and
smallest capacity is kept slight in order to save as much water under pressure as
practicable, for effecting the return movement of the piston.
When the drawn-out piston is to be moved back, the press-cylinder is connected
with the exhaust-pipe and the auxiliary cylinder with the pressure-main, the afore-
said cock being suitably adjusted. The fluid under pressure then enters the
auxiliary cylinder and pushes together the telescopic piston and consequently the
pipes attached thereto. When the plug of the cock is turned through an angle
of 90 degrees, so that the press-cylinder again receives fluid under pressure, and
the auxiliary cylinder is connected with the exhaust, the pistons are moved
outward, the largest piston and the second piston carrying with them the pipes
attached thereto. The annular spaces then become gradually smaller, and the
liquid contained in them escapes through the channels into the increasing space
in the auxiliary cylinder, whilst only a small portion of the same flows to the
exhaust.
Dated this 6th day of June 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Hydraulic Presses having
Telescopic Pistons.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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 apparatus for effecting the return movement of a
telescopic piston in a hydraulic press, after the outward stroke has been completed,
by the fluid under pressure.
In presses having a single or simple piston, the return movement can be provided
for, as is well known, by making the piston not in the form of a plunger, but as a
double-acting piston, and conducting the fluid under pressure (after the completion
of the outward stroke and after the opening of the exhaust valve of the cylinder)
into the annular space in front of the said piston.
The problem becomes more difficult if, by reason of local conditions, it is necessary
to employ a telescopic piston.
The present invention solves this problem by the construction of the several
parts or sections of the telescopic piston as double-acting pistons, and the provision
of suitable means whereby the annular spaces in front of the several sections may
be connected by a common pipe with the force-pumps, the accumulator or the
pressure-main on the one hand, and with the exhaust reservoir or main on the
other hand.
In the drawing is represented a press having a telescopic piston formed of three
parts or sections, and constructed according to this invention.
Figure 1 is a central longitudinal section of the said press, and
Figure 2 is a transverse section on the line, a Figure 1.
To the press-cylinder A. which is made in one piece with a second smaller or
auxiliary cylinder B arranged parallel therewith, the fluid under pressure is
conducted through a four-way cock C or other suitable distributing device. In
the said press-cylinder A. slides a piston D which is bored out cylindrically; in the
hore of the piston D slides a second smaller piston E which is also bored out
cylindrically, and in this piston slides a still smaller piston F which may be solid
if the telescopic piston is formed of only three parts or sections.
The annular-space a in front of the piston D'communicates, through a channel b

page_text: at the front end of the press-cylinder A with the auxiliary cylinder B. The annula
space c in front of the second piston E also communicates with the cylinder B,
through a channel d in the wall of the largest piston D at the front end of the
same, and through a suitable pipe G. The pipe G extends into the auxiliary
cylinder B, through a stuffing gland, and is firmly connected with the piston D so
that it must participate in the movement of the latter. In like manner, the annular
space e in front of the smallest piston F is in communication with the cylinder B
through a channel and through a pipe H which extends through a stuffing gland
in the head of the pipe G. The press cylinder A, moreover, communicates with
one of the four ways of the cock C through a pipe i.
The transverse section of the annular space c is somewhat larger than the
transverse section of the pipe G, and the transverse section of the space e is some-
what larger than the transverse section of the pipe H. The capacity of the fluid
space in the cylinder B and in the annular spaces a, c, e will, therefore, be greatest
when the telescopic piston is completely extended, and smallest when the said
telescopic piston is completely pushed in or contracted. The difference between
the greatest and smallest capacity is kept slight in order to save as much water
under pressure as practicable for effecting the return movement of the piston.
The cylinder B communicates with the four way cock C by a pipe h, and the
press cylinder A communicates with the said cock by a pipe i. 1, J Figure 2 are
the supply and exhaust pipes respectively leading to and from the cock C.
When the extended piston is to be moved back, the cock C is adjusted to place
the press-cylinder A in communication with the exliaust-pipe J, and the cylinder B
with the supply-pipe I. The fluid under pressure then enters the cylinder Band
pushes together or closes the telescopic piston and consequently the pipes G and H.
When the plug of the cock C is turned so that the cylinder A again receives fluid
under pressure, and the cylinder B is connected with the exhaust, the pistons D, E
and Fare moved outward, the piston D carrying with it the pipe G and the piston E
carrying with it the pipe H. The annular spaces a, cand e thus become gradually
contracted, and the liquid contained in them escapes through the channels into the
increasing space in the cylinder B whilst only a small portion of the same flows
to the exhaust through the pipe 7.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to me
by my foreign correspondents, I declare that what I claim is :-
1. A hydraulic press having a telescopic piston, wherein the annular spaces in front
of the double acting sections or parts of the said piston are by means of sliding
pipes connected to the said parts maintained in permanent communication with an
auxiliary cylinder which communicates with the distributing cock, for the purpose
specified.
2. A hydraulic press constructed substantially as described with reference to the
accompanying drawing, and operating as specified.
Dated this 11th day of February 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.