Improvements in Apparatus for Operating Hydraulic Presses and the like.
Year: 1893

page_text: te of Application, 14th Nov., 1893--Accepted, 16th Dec., 1893
COMPLETE
SPECIFICATION.
Improvements in Apparatus for Operating Hydraulic Presses and
the like.
We, CHARLES MUSKER and ARTHUR MUSKER, of Dundas Street, Bootle,
near Liverpool, in the County of Lancaster, Engineers, 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 :-
2
Our invention relates to apparatus for operating hydraulic presses where the
pressure in the hydraulic main supply pipe, (hereinafter referred to as the main),
is less than that finally required in the press or the like, and where, therefore,
a pressure intensifier is used; and the object of our invention is to supply
simple and reliable arrangement of valves and operating gear, whereby various
pressures can be obtained in the press by the movement of a single hand lever,
while at the same time, the water is economised.
The form of intensifier which we prefer to use, consists of a fixed cylinder
provided with a movable hollow movable ram working over a fixed plunger
which enters the hollow ram as the latter is forced out of the cylinder. The
communication from without with the interior of the movable ram is made by
a passage through the fixed plunger, and as the cross-sectional area of the latter
is less than that of the movable ram, it will be seen that the apparatus may
be used either as a pressure intensifier or a pressure reducer, accordingly as the
water from the main is used as the motive power in the cylinder or within the
movable ram. Our invention may, however, be used in conjunction with an
intensifier of any suitable kind, and as such an apparatus consists, in effect, of
a larger cylinder having a piston which is coupled to a smaller piston working
within a smaller cylinder, we will, for convenience of description, refer generically
hereinafter to the large and small cylinder of the intensifier.
The cycle of operations which our apparatus is intended to effect is as
follows;-
Assuming that the large cylinder of the intensifier is in connection with the
main, that the small cylinder communicates with the press or the like, and that
the latter has completed its working stroke under the intensified pressure, it
will be seen that if, at this stage, the large cylinder of the intensifier be put
to waste to make it ready for its next stroke, all the water therein will be
wasted. We, however, at this stage, after running the water in the press to
waste and returning its ram ready for the next stroke, reverse the connections
described, that is to say, we put the large cylinder of the intensifier, which is
full of water, in communication with the press, and the small cylinder of the
intensifier in communication with the main, with the result that the contents of
the large cylinder are expelled wholly or partially into the press, thus making
the first part of the working stroke of the latter, and effecting an economy
with respect to the water so used. The pressure thus obtained in the press is less
than that in the supply main in proportion as the cross sectional area of the
small cylinder is less than that of the large cylinder, but as the resistance to
be overcome at this stage by the press is less than the final resistance, we find
it economical to use the lower
resistance to be overcome: w: pressure and so proportion the pressure to the
this object still in view, we next connect the
press with the supply main and put the large cylinder of the intensifier to
waste, leaving the small cylinder thereof in communication with the supply main;
the second portion of the working stroke of the press is thus performed at the
pressure of the main, and any water remaining in the large cylinder of

page_text: the intensifier is expelled as its piston is forced in.
To complete the working
stroke of the press at the intensified pressure, it is now only necessary to, put
the press in communication with the small cylinder of the intensifier, and to
connect the large cylinder of the latter to the main.
We effect the various operations described by means of the apparatus shown
in the accompanying drawings, in which
Fig. I is a sectional elevation on the line A. A. of Fig. II,
Fig. II is a plan with the slide valve and box cover removed;
Fig. 1II is a sectional end elevation on the line B. B. of Fig. IV, and
Fig. IV is a sectional plan on the line C. C. of Figs. I and II.
Figs. V, VI and VII are diagrams to show more clearly the cycle of operations,
the parts being shown and arranged conventionally so as to best indicate their
action at the various stages.
Throughout the drawings the same parts are indicated by the same reference
figures.
5 is the valve box, closed by the cover 6, and supplied from the main by the
passage 7.
The slide valve 8, which is operated by the valve rod 9, has a cavity 10 and
a port 11, which latter passes through the valve, being forked to clear the valve
rod, as shown in Fig. III; 12 is a secondary valve or plate incapable of longi-
tudinal movement, whose function is to close the through port 11 in certain
positions of the latter, as hereinafter described.
The slide valve 8 is adapted to control the four passages 1, 2, 3, and 4, which
end in corresponding ports in the port face and communicate respectively with
the small cylinder of the intensifier, the press, the large cylinder of the intensifier,
and the waste.
The passage I is provided with the non-return valve 13, and the passage 2
with the non-return valve 14; these valves are loaded with light springs and
are shown in dotted lines in Figs. III and IV. The passages 1 and 2 are
connected, beyond their respective non-return valves, by the by-passage 15 which
is controlled by the slightly spring loaded by-pass valve 16, operated by the
spindle 17, the lever 18 fulcrummed at 19, and the tappet pin 20 on the slide
valve rod. The object of the valves 13, 14 and 16, and the by-passage 15 will
be described in considering the action of the apparatus.
There are no valves in the passages 3 and 4, and as the passages 4 and 2 have to
cross, we arrange the latter at a lower level where they do so (see Figs. III
and IV).
The action of the apparatus is as follows, reference being made to the
diagrammatic Figures V, VI and VII.
Assuming that the press is nearly at the end of its stroke under the intensified
pressure, the slide valve is in its extreme position to the left, and the tappet 20 has
engaged the lever 18, opening the valve 16, as shown in Fig. V. The water from
the main passes through the valve port 11 to the large cylinder of the intensifier,
and the water under intensified pressure from the small cylinder of the intensifier
returns by the passage 1 as far as the non-return valve 13 which closes, then through
the by-passage 15 and open by-pass valve 16 on to the passage 2, beyond the non-
return valve 14, and thence to the press.
Supposing now that the press stroke is completed, the water therein run to waste
and its ram returned ready for the next stroke; the slide valve is moved to the
position shown in Fig. VI, and the valve 16 closes. Water from the main now
flows to the small cylinder of the intensifier through the passage 1 and valve 13,
and the water already in the large cylinder of the intensifier returns through the
passage 3 under reduced pressure and passes on to the press through the valve
cavity 10 and passage 2 and valve 14, thus completing the first part of the press
stroke. The valve 16 closes the by-passage 15 during this phase. In the mean-
time, as the through port 11 is over the waste port 4 it is closed by the fixed valve
or plate 12. The intensifier may or may not make its full stroke at this stage;

page_text: this will depend upon the rate at which the resistance to the press increases as the
stroke is made.
.
The second part of the press stroke is effected by moving the slide valve to the
position shown in Fig. VII, which uncovers the port 2, so admitting water from the
main to the press.
At the same time, the slide valve cavity couples the passage 3
from the large cylinder of the intensifier to the waste passage 4, and as the passage 1
is still open to the main, the stroke of the intensifier is completed ready for the
final part of the press stroke, which is effected by returning the slide valve to the
position shown in Fig. V.
The valve rod 9 is operated by hand by the attendant but its movement may be
automatically regulated by movable stops operated by the pressure in the press,
which stops hold the valve in one position until the pressure in the press for that
position attains a maximum.
It will be seen, from an inspection of Figs. V, VI and VII, that the non-return
valves 13 and 14 and the by-passage 15 and by-pass valve 16 are collectively not
essential. If omitted, the action in the phases shown in Figs. VI and VII would
be unaffected, and in the phase shown in Fig. V, the water under intensified
pressure would pass from the passage 1 to the passage 2 through the valve cavity 10
which couples the corresponding ports. In this case however, the intensified
pressure below the valve would tend to lift it from the port face and we find it
decidedly preferable to fit such an arrangement of by-passage and by-pass and non-
return valves as is shown, which constitutes an important feature of our invention.
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. The improved apparatus for operating hydraulic presses and the like,
comprising a slide valve having a cavity and a through port and adapted to control
four passages connected respectively with the small cylinder of a pressure intensifier,
the press or the like, the large cylinder of the intensifier and the waste;
substantially as and for the purpose described.
2. In apparatus such as is herein set forth, the combination of a slide valve
having a cavity adapted to connect a pressure intensifier to a press or the like, and
the hereindescribed arrangement of by-passage and by-pass and non-return valves,
whereby the access of the intensified pressure to the face of such slide valve is
prevented;-substantially as described and illustrated.
3. In apparatus as herein set forth, and in combination with the slide valve 6,
the use of a by-pass valve 16 adapted to be operated by a tappet 20 on the valve
rod-substantially as and for the purpose described and illustrated.
4. In apparatus as herciu set forth, the combination, with the slide valve 8 having
a cavity and a through port 11, of a fixed valve plate 12 adapted to close the said
port 11 in certain positions of the latter;-substantially as and for the purpose
described and illustrated.
5. The combination and arrangement of parts forming the improved apparatus
for operating hydraulic presses and the like, substantially as described and
illustrated in Figs. I to IV.
Dated thio 12th day of November 1902
SLOAN & LLOYD BARNES,
Castle Chambers, 26, Castle Street, Liverpool,
Agents for the Applicants.