Information
-
Patent Grant
-
6526879
-
Patent Number
6,526,879
-
Date Filed
Tuesday, February 29, 200024 years ago
-
Date Issued
Tuesday, March 4, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 100 46
- 100 258 A
- 100 258 R
- 100 26906
- 100 207
- 060 428
- 060 475
- 060 494
- 091 171
- 091 183
-
International Classifications
-
Abstract
A press for fabrication of building components including: an upper platen; a lower platen; the upper platen and/or lower platen movable towards and away from the other; a first and second hydraulic device located on a base, each hydraulic device including; a cylinder; a piston located in the cylinder defining a first and a second chamber in the cylinder, the piston sealingly engaging the cylinder and movable in the cylinder; and a piston rod connected to the piston and extending through the second chamber to engage the upper or lower platen; a pump to pump hydraulic fluid into the first chamber of the first hydraulic device; and a valve in fluid communication with the first chambers of the first and second hydraulic devices to selectively withdraw hydraulic fluid from the first chamber of either or both the first and second hydraulic devices to align the upper and lower platens.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to a press having a hydraulically controlled platen. More particularly, the press is useful for the manufacture of prefabricated building components (such as trusses) or other building components. It may also be useful in processing other articles (such as plastic sheet, plastic pipe, sheet and metal articles such as aluminum extrusions, laminated and composite timber articles).
2. Description of the Related Art
Whilst the following discussion illustrates the press used for manufacture of prefabricated building components, it is to be understood that the press may be used in other engineering applications.
Traditionally, trusses that are destined for the building industry may be constructed on-site or prefabricated. Prefabricated trusses of standard designs are very popular as they can be mass-produced by passing the assembled components between a press which fixes the components together at appropriate locations.
Typically, such presses have an upper and/or lower platen against which the fixing occurs. One form of press, which is in use in the building component prefabrication industry, has a lower platen and an upper moving platen which is designed to press down on the components disposed in between them. The pressing action pushes fasteners into the components to form timber joints of a truss assembly. The components need to be held firmly during the fixing operation to produce strong and uniform trusses. Considerable pressure is applied to the lower platen indirectly during the holding and fixing of the timber joint to achieve this. Further, the fixing is usually localized to relatively small areas of the platen where the joint to be formed is located. This area may vary across the platen depending upon where the proposed joint is positioned.
Consequently, the lower platen has to be supported by devices which prevent it moving or tilting in response to any localized pressure applied to it. A number of these types of devices have been proposed.
In Australian patent no. 543663 a hydraulic press is disclosed. A pair of rams are each provided with a hydraulic device under the tool. They are connected by a torsion bar which regulates the fluid flow into the hydraulic rams in the event that it becomes misaligned. A complex combination of bars, rocking members and springs are used to maintain the tool level.
In another arrangement, a series of manually or automatically controlled levers are provided to mechanically regulate the movement and alignment of the platen of a press. Again, this is complex and is not readily adapted to automate and regulate the pressing function of the machine.
It is an objective of the present invention to provide a press with improved adjustment of the alignment of at least one of its pressing components.
SUMMARY OF THE INVENTION
Accordingly there is provided a press for fabrication of building components including: (a) an upper platen; (b) a lower platen; (c) first and second hydraulic devices each including; (i) a cylinder; (ii) a piston located in the cylinder defining a first and a second chamber in the cylinder, the piston sealingly engaging the cylinder and movable in the cylinder; and (iii) a piston rod connected to the piston and extending through the second chamber, wherein the first and second chambers, each have an inlet/outlet for hydraulic fluid and the second chamber of the first hydraulic device is in fluid communication with the first chamber of the second hydraulic device; and each piston rod of each hydraulic device extends in engagement with one and the same of the upper or lower platens, whereby the hydraulic devices are operable to shift the upper or lower platen the piston rods engage, relatively toward or away from the other of the upper or lower platens, (d) a pump to pump hydraulic fluid into the first chamber of the first hydraulic device; and (e) a valve in fluid communication with the first chambers of the first and second hydraulic devices to selectively withdraw hydraulic fluid from the first chamber of either or both the first and second hydraulic devices to align the upper and lower platens.
In operation, hydraulic fluid is pumped into the first chamber of the first hydraulic device by the pump which causes the piston to move towards the inlet/outlet of the second chamber. The second chamber decreases in volume and forces hydraulic fluid through the inlet/outlet of the second chamber of the first hydraulic device into the first chamber of the second hydraulic device. This in turn, causes a similar displacement of the piston in the second hydraulic device and fluid present in the second chamber of the second hydraulic device flows through the inlet/outlet.
As will be well understood by engineers, hydraulic fluid is substantially incompressible and is a medium which can translate motive forces very well.
In another preferred form of the invention there is provided, a press for fabrication of building components including: (a) an upper platen connected to an upper part of a frame; (b) a lower platen; (c) spaced first and second hydraulic devices each connected at one and the same end thereof to the frame and each including; (i) a cylinder; (ii) a piston located in the cylinder defining a first and a second chamber in the cylinder, the piston sealingly engaging the cylinder and movable in the cylinder; and (iii) a piston rod connected to the piston at one end thereof and extending through the second chamber into engagement with the lower platen at the other end of the device to that connected to the frame; wherein the first and second chambers, each have an inlet/outlet for hydraulic fluid, and the second chamber of the first hydraulic device is in fluid communication with the first chamber of the second hydraulic device; (d) a pump to pump hydraulic fluid into or from the first chamber of the first hydraulic device to cause the piston rods of both hydraulic devices to move and to shift the upper or lower platen relatively towards or away from the other platen; and (e) a valve in fluid communication with the first chambers of the first and second hydraulic devices to selectively withdraw hydraulic fluid from the first chamber of either or both the first and second hydraulic devices to align the upper and lower platens.
In yet another preferred form of the invention there is provided, a press for fabrication of building components including: (a) an upper platen connected to an upper frame; (b) a lower platen connected to a lower frame; (c) spaced first and second hydraulic devices, each including; (i) a cylinder; (ii) a piston located in the cylinder defining a first and a second chamber in the cylinder, the piston sealingly engaging the cylinder and movable in the cylinder; and (iii) a piston rod connected to the piston at one end thereof and extending through the second chamber; wherein the first and second chambers, each have an inlet/outlet for hydraulic fluid, and the second chamber of the first hydraulic device is in fluid communication with the first chamber of the second hydraulic device; and each of the hydraulic devices is connected at one end to the upper frame and at the other end to the lower frame, one of the connections being with the end of the piston rods extending from the second chambers, and the devices being operable by extension or retraction of the piston rods thereof to shift the upper or lower platen relatively toward or away from the other; (d) a pump to pump hydraulic fluid into or from the first chamber of the first hydraulic devices to cause the piston rods of both hydraulic devices to move and to shift the upper or lower platen relatively towards or away from the other platen; and (e) a valve in fluid communication with the first chambers of the first and second hydraulic devices to selectively withdraw hydraulic fluid from the first chamber of either or both the first and second hydraulic devices to align the upper and lower platens.
According to another preferred form of the invention, a press for fabrication of building components is provided including: (a) an upper platen; and (b) a lower platen; (c) first and second hydraulic devices each including; (i) a cylinder having a partition sealingly engaging the walls of the cylinder and located intermediate the ends of the cylinder, to define first and second chambers of the cylinder; (ii) a first piston located in the first chamber and defining (a) a first sub-chamber between an end of the cylinder and the first piston and (b) a second sub-chamber between the first piston and the partition, the first piston sealingly engaging the cylinder and movable in the cylinder; (iii) a second piston located in the second chamber and defining (c) a third sub-chamber between the partition and the second piston and (d) a fourth sub-chamber between the second piston and the other end of the cylinder, the second piston sealingly engaging the cylinder and movable in the cylinder; and (iv) a piston rod connected to the first piston and the second piston and passing through and sealingly contacting the partition; and further extending from the fourth sub-chamber; wherein the first sub-chamber has an inlet for hydraulic fluid, the second sub-chamber has an outlet for hydraulic fluid, the third sub-chamber has an inlet/outlet for hydraulic fluid and the fourth sub-chamber has an inlet/outlet for hydraulic fluid; and the inlet/outlet of the third sub-chamber of one of the hydraulic devices is in fluid communication with the inlet/outlet of the fourth sub-chamber of the other hydraulic device; and each of the hydraulic devices is connected at one end to the upper frame and at the other end to the lower frame, one of the connections being with the end of the piston rods extending from the fourth sub-chamber and each device is operable by extension or retraction of the piston rods thereof to shift the upper or lower platens relatively toward or away from the other; (d) a pump to pump hydraulic fluid into the first sub-chamber of each of the hydraulic devices; and (e) a valve in fluid communication with the first sub-chambers of the first and second hydraulic devices to selectively withdraw hydraulic fluid from the first sub-chamber of either or both the first and second hydraulic devices to align the upper and lower platens.
In operation, hydraulic fluid flows into the sub-chamber of each of the hydraulic devices to apply a load. Typically the load applied to each hydraulic device is different. The pressure applied causes the first and second piston to move which reduces the volume of the fourth sub-chamber of each hydraulic device.
When the load is different on each hydraulic device, the fluid from the fourth sub-chamber which is under the greater pressure, forces fluid into the third sub-chamber of the other hydraulic device. This transmits an additional force to the second piston of that other hydraulic device until its fourth sub-chamber has an equal pressure to the fourth sub-chamber of the first hydraulic device.
In this way, the press reacts quickly to equalize the pressure being applied to the platen which minimizes potential misalignment of the platen.
The press according to the invention, uses the interaction of the hydraulic fluid in the cylinders as the means to maintain the platen substantially level (horizontal) irrespective of the localization of the load imposed by the tool on the platen. Accordingly, the formation of building components, between the upper platen and lower platen over extended periods of use and repetition, is consistently of a high reproducible quality.
Over time, the seals which form the sealing engagement of the piston with the cylinder will degrade and fluid will leak between the chambers in each hydraulic device. As this occurs, the total volume of fluid which resides in the chambers will change. This results in the platen becoming tilted.
Accordingly, to ameliorate this the valve is incorporated to correct any imbalance between the relative position of the pistons in the cylinders.
Preferably, the valve is located in either or both the pistons and is pressure actuated. In this embodiment, the pistons are preferably provided with a passageway which communicates between the chambers of the cylinder. The valve is located in the passageway and under predetermined pressure conditions permits hydraulic fluid to pass from one chamber to another.
In an alternate embodiment, the valve is located externally of the cylinders in a hydraulic fluid line which communicates with a reservoir of hydraulic fluid. The fluid line is connected to each of the cylinders. If the fluid pressure exceeds the predetermined amount in a cylinder, the valve opens to permit hydraulic fluid to flow out and correct any imbalance between the relative positions of the pistons in the cylinders.
In another alternate embodiment, the valve is externally of the cylinders in hydraulic fluid lines which communicate between the hydraulic devices.
In another alternate embodiment, the valve may be actuated in response to sensor signals. Sensors (e.g. electrical limit switches) are positioned to detect the position or alignment of the platen. If predetermined limits are exceeded, the sensors cause the valve or valves associated with either or both the cylinders to open. The pistons are therefore rebalanced to restore the desired alignment.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be further explained and illustrated by reference to the accompanying drawings in which:
FIG. 1
is a simplified front view of a press;
FIG. 2
is a simplified front view of the press of
FIG. 1
with a misaligned platen;
FIG. 3
is a front view of a press according to a first form of the invention;
FIG. 4
is a front view of a press according to a second form of the invention;
FIG. 5
is a front view of a press according to a third form of the invention;
FIG. 6
is a front view of a press according to a fourth form of the invention;
FIG. 7
is a front view of a press according to a fifth form of the invention;
FIG. 8
is a side view of the press of
FIG. 7
;
FIG. 9
is a front view of a press according to a sixth form of the invention;
FIG. 10
is a side view of the press of
FIG. 9
;
FIG. 11
is a conceptual illustration of a press according to a seventh form of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the drawings like elements are designated by the same numbers.
FIGS. 1 and 2
are conceptual illustrations of a press
1
in different positions. Press
1
has an upper platen
2
and a lower platen
3
. Both platens
2
and
3
are movable towards one another. An article (not shown) to be fabricated is disposed in the space
4
. As the platens
2
and
3
converge, they hold the article in position to permit fasteners or the like to penetrate the article at the desired position. This means that localized impact forces may occur across the lower platen
3
. These localized forces may cause the platens
2
and
3
to become misaligned as shown in FIG.
2
. If the machine is automated and is carrying out repetitive fabrication steps, the integrity of the fabrication may be adversely affected.
FIG. 3
shows a form of press
100
according to the invention. Like parts from
FIGS. 1 and 2
have the same reference numerals, plus
100
. Lower platen
103
is supported by a pair of hydraulic cylinders
105
and
106
. Cylinders
105
and
106
are connected to the lower platen
103
by piston rods
107
and
108
. Piston rods
107
and
108
are connected to pistons
109
and
110
which are in sealing engagement with the walls of cylinders
105
and
106
. Piston
109
defines chambers
111
and
112
in cylinder
105
. Piston
110
defines chambers
113
and
114
in cylinder
106
.
Cylinder
105
has a fluid inlet/outlet
115
in chamber
111
and a fluid inlet/outlet
116
in chamber
112
. Cylinder
106
has a fluid inlet/outlet
117
in chamber
113
and a fluid inlet/outlet
118
in chamber
114
.
Fluid line
119
connects inlet/outlet
116
to inlet/outlet
117
. Fluid line
120
connects the inlet/outlet
118
to a reservoir/pump
121
. Fluid line
122
connects reservoir/pump
121
to inlet/outlet
115
.
In operation if the platen
103
is subjected to a localized load, the pressure will be spread differentially across the platen and transmitted differentially to the two piston rods
107
and
108
. Assuming the greater load is transferred to the cylinder
106
, the piston rod
108
causes the piston
110
to move against the fluid in the chamber
113
. The residue of the load is applied to the piston rod
107
which in turn attempts to move the piston
109
. Chamber
113
of cylinder
106
is in fluid communication with the chamber
112
of cylinder
105
via fluid line
119
. Any movement of the two pistons is matched by the flow of fluid from the chamber
113
into chamber
112
. The platen
103
is thereby maintained substantially level (horizontal) and does not tilt.
Likewise to raise platen
103
to carry out the fabrication, hydraulic fluid is pumped from reservoir/pump
121
through fluid line
122
into chamber
111
. This urges piston
109
up and hydraulic fluid in chamber
112
is displaced to chamber
113
via fluid line
119
. This in turn forces piston
110
up and hydraulic fluid is expelled to the reservoir/pump
121
via fluid line
120
. In this way a distributed lifting force is applied across platen
103
to ensure that it remains substantially horizontal. To lower platen
103
the reverse procedure is carried out.
In
FIG. 4
a press
200
includes many of the features of
FIGS. 1
to
3
and those features have the same third, or second and third numbers. A recycling valve
223
is interposed into fluid line
220
and a branch fluid line
224
extends from the recycling valve
223
to fluid line
222
. In operation, when platen
203
is being raised, the volume of hydraulic fluid which is being pumped from the reservoir/pump
221
to cylinder
205
can be significantly reduced by opening recycle valve
223
to allow fluid being expelled through inlet/outlet
218
to flow via fluid lines
220
,
224
and
222
to inlet/outlet
215
.
In
FIG. 5
a press
300
is shown with the same reference numeral structure as FIG.
4
. This arrangement
300
is appropriate to compensate for any leaks in the seal between the pistons
309
and
310
and the cylinders
305
and
306
respectively. Over time, these seals will degrade and fluid will leak between the chambers
311
and
312
and/or chambers
313
and
314
. As this occurs, the total volume of fluid which resides in chambers
312
,
313
and/or chambers
313
,
314
and fluid line
319
increases. As such, the relative position of the pistons
309
and
310
will change and platen
303
will be tilted.
To compensate for these leaks, one or more valves can be incorporated which are either pressure actuated or actuated using remotely generated signals. As shown in
FIG. 5
, fluid lines
326
and
328
are connected to chambers
311
and
313
, respectively and also connect to valve
325
. In the event that the chambers
311
and
313
are out of balance, valve
325
opens either or both fluid lines
326
and
328
to permit pistons
309
and
310
to again be in a balanced relationship by hydraulic fluid flowing through fluid line
327
.
Likewise, a compensation circuit is connected to chambers
312
and
314
via fluid lines
330
and
331
. These fluid lines
330
and
331
are both connected to valve
329
which can selectively permit fluid to flow from either or both chambers
312
and
314
to fluid line
332
.
In
FIG. 6
a press
400
is shown, with the same reference numeral structure as FIG.
4
. An alternate compensating arrangement is shown. For simplicity only, none of the external circuit is shown. However, the external circuitry as shown in FIG.
3
. would be suitable. The internal compensatory circuit uses valves
435
and
436
disposed in passageways
433
and
434
. As shown, the pistons
409
and
410
are out of alignment due to wearing of the seals (not shown). By opening valve
435
fluid can flow from chamber
412
to chamber
411
. By opening valve
436
fluid can flow from chamber
414
to chamber
413
. Typically the valves
435
and
436
are pressure actuated and only open for a time sufficient to permit the pistons
409
and
410
to be rebalanced.
FIGS. 7 and 8
show a practical arrangement of a press
500
according to the invention. The circuitry is not shown but would typically be that disclosed in FIG.
4
. The press
500
is mounted on a carriage
537
which has four wheels
538
. The wheels
538
engage and roll along a pair of lower flanges of rails
539
. The wheels
538
are connected by axles
540
.
The carriage
537
has a base frame which is composed of a pair of spaced upright plates
541
which are connected by platen
542
(which is also the upper platen) and a pair of plates
543
. A recess is formed by the plates
541
and platen
542
in which a hydraulic power pack
544
resides. Hydraulic power pack
544
controls the fluid circuitry (not shown).
Located in between the plates
541
is a lower sub-frame
545
. Hydraulic cylinders
505
and
506
are connected to sub-frame
545
whilst the piston rods
507
and
508
are connected to plates
543
in the base frame. Sub-frame
545
has a lower platen
546
. In operation, the article
547
to be fabricated is to be held between upper platen
542
and lower platen
546
. To move the lower platen
546
upward, fluid is pumped into chamber
512
(as shown in
FIG. 4
) and accordingly fluid is displaced from chamber
511
to chamber
514
. The upper platen
542
is initially lowered until it rests on the article
547
. The lower platen
546
is then raised to sandwich article
547
with upper platen
542
and lift the four wheels
538
off the rails
539
. The reverse procedure is followed to lower the lower platen
546
.
FIGS. 9 and 10
show another practical arrangement of a press
600
according to the invention. Again the circuitry is not shown but would typically be that disclosed in FIG.
4
. The press
600
is mounted on a carriage
637
which has four wheels
638
. The wheels
638
engage and roll along a pair of lower flanges of rails
639
. The wheels
638
are connected by axles
640
which are in turn connected to the lower platen
648
.
The carriage
637
has a base frame which is composed of a pair of spaced upright plates
641
which are connected by platen
642
(which is also the upper platen) and a pair of plates
643
. A recess is formed by the plates
641
and platen
642
in which a hydraulic power pack
644
resides. Hydraulic power pack
644
controls the fluid circuitry (not shown).
Located in-between the plates
641
and on the plates
643
are hydraulic cylinders
605
and
606
. Piston rods
607
and
608
are connected to lower platen
648
. In operation, the article
647
to be fabricated is between upper platen
642
and lower platen
648
. To initially move the upper platen
642
downward and then move the lower platen upward, fluid is pumped into chamber
611
(equivalent to chamber
211
as shown in
FIG. 4
) and accordingly fluid is displaced from chamber
612
to chamber
613
. The lower platen
648
is finally raised to sandwich article
647
with upper platen
642
which movement raises the wheels
638
off the rails
639
. The reverse procedure is followed to lower the lower platen
648
.
FIG. 11
shows conceptually another alternative. Press
700
has a lower platen
702
and an upper platen
703
. Both platens
702
and
703
are movable towards one another. An article (not shown) to be fabricated is disposed in the space
704
. As the platens
702
and
703
converge, they hold the article in position to permit fasteners or the like to penetrate the article at the desired position. This means that localized impact forces may occur across the lower platen
703
. These localized forces may cause the platens
702
and
703
to become misaligned. If the machine is automated and is carrying out repetitive fabrication steps, the integrity of the fabrication may be adversely affected.
Upper platen
703
is controlled by a pair of hydraulic cylinders
705
and
706
. Cylinders
705
and
706
are connected to the upper platen
703
by piston rods
707
and
708
. Piston rods
707
and
708
are connected to pistons
709
and
710
in cylinder
705
and pistons
711
and
712
of cylinder
706
respectively. These pistons are in sealing engagement with the walls of the cylinders.
Intermediate piston
709
and
710
is partition
713
, whilst intermediate pistons
711
and
712
is partition
714
. These partitions
713
and
714
sealingly engage cylinders
705
and
706
and also permit piston rods to pass therethrough in a sealed arrangement.
The upper ends of cylinders
705
and
706
define first sub-chambers A and B with pistons
710
and
712
respectively. The pistons
710
and
712
define second sub-chambers C and D with partitions
713
and
714
respectively. The pistons
709
and
711
define third sub-chambers E and F with partitions
710
and
712
respectively. The lower ends of cylinders
705
and
706
define fourth sub-chambers G and H with pistons
709
and
711
respectively.
The first sub-chambers A and B have an inlet
715
and
716
for hydraulic fluid from a hydraulic fluid pump
717
. The second sub-chambers C and D have an outlet
718
and
719
for hydraulic fluid. The third sub-chambers have an inlet/outlet
720
and
721
for hydraulic fluid. The fourth sub-chambers have an inlet/outlet
722
and
723
for hydraulic fluid. Fluid line
724
connects inlet/outlet
721
and
722
, whilst fluid line
725
connects inlet/outlet
720
and
723
.
To compensate for any leaks between the sub-chambers, one or more valves
726
can be incorporated which are either pressure actuated or actuated using remotely generated signals. Also, valve lines
727
and
728
may be provided to connect the first sub-chambers A and B with a valve
729
, so that if chambers A and B are out of balance, valve
729
opens either or both of fluid lines
727
and
728
to permit pistons
710
and
712
to be balanced by fluid flowing through line
730
. This arrangement is effectively the same as that shown in
FIG. 5
in relation to the valve
325
.
In operation, hydraulic fluid flows into the first sub-chamber A and B of each of the hydraulic cylinders
705
and
706
to apply a load. The load applied to each cylinder
705
and
706
is invariably different. The pressure applied causes the pistons
709
and
710
, and
711
and
712
to move which reduces the volume of the fourth sub-chambers G and H.
When the load is larger in hydraulic cylinder
705
than in hydraulic cylinder
706
, the fluid from the fourth sub-chamber G of cylinder
705
, forces fluid into the third sub-chamber (F) of cylinder
706
. This transmits an additional force to piston
711
of cylinder
706
until fourth sub-chamber H has an equal pressure to the fourth sub-chamber G of cylinder
705
.
In this way, the press reacts quickly to equalize the pressure being applied to the platen which minimizes potential misalignment of the platen.
Presses according to the invention, use the interaction of the hydraulic fluid in the cylinders as the means to maintain the platen substantially level (horizontal) irrespective of the localization of the load imposed by the tool on the platen. Improvements and modifications will be readily apparent to those skilled in the art and are considered to be within the scope and spirit of the invention.
Claims
- 1. A press comprising:a) an upper platen; b) a lower platen; c) a first and second hydraulic device each including: i) a cylinder; ii) a piston located in the cylinder defining a first and a second chamber in the cylinder, the piston sealingly engaging the cylinder and movable in the cylinder; and iii) a piston rod connected to the piston and extending through the second chamber, wherein the first and second chambers, each have an inlet/outlet for hydraulic fluid and the second chamber of the first hydraulic device is in fluid communication with the first chamber of the second hydraulic device; and wherein each piston rod of each hydraulic device engages one of the upper and lower platens whereby the hydraulic devices are operable to shift, relatively, the platen with which the pistons rods are engaged toward or away from the other platen, d) a pump to pump hydraulic fluid into the first chamber of the first hydraulic device; and e) a valve in fluid communication with the first chambers of the first and second hydraulic devices, wherein said valve is adapted to respond to a pressure in either of said first chambers measured by a sensing means upon a misalignment of said platens, and wherein said valve is adapted to selectively withdraw hydraulic fluid from the first chamber of either or both the first and second hydraulic devices to align the upper and lower platens.
- 2. A press according to claim 1, wherein the pump is additionally adapted to pump hydraulic fluid from the first chamber of the first hydraulic device.
- 3. A press according to claim 1, wherein the valve is adapted to correct any imbalance between the relative positions of the pistons in the cylinders.
- 4. A press according to claim 3, wherein the valve is located externally of the cylinders in a hydraulic fluid line which communicates between the hydraulic devices.
- 5. A press according to claim 3, wherein the valve is located externally of the cylinders in a hydraulic fluid line connected to each of the cylinders which communicates with a reservoir for hydraulic fluid.
- 6. A press comprising:a) an upper platen connected to an upper part of a frame; b) a lower platen; c) spaced first and second hydraulic devices each connected at one and the same end thereof to the frame and each including: i) a cylinder; ii) a piston located in the cylinder defining a first and a second chamber in the cylinder, the piston sealingly engaging the cylinder and movable in the cylinder; and iii) a piston rod connected to the piston at one end thereof and extending through the second chamber into engagement with the lower platen at the other end of the device to that connected to the frame; wherein the first and second chambers, each have an inlet/outlet for hydraulic fluid, and the second chamber of the first hydraulic device is in fluid communication with the first chamber of the second hydraulic device; d) a pump to pump hydraulic fluid into or from the first chamber of the first hydraulic device to cause the piston rods of both hydraulic devices to move and to shift, relatively, the upper or the lower platen towards or away from the other platen; and e) a valve in fluid communication with the first chambers of the first and second hydraulic devices, wherein said valve is adapted to respond to a pressure in either of said first chambers measured by a sensing means upon a misalignment of said platens, and wherein said valve is adapted to selectively withdraw hydraulic fluid from the first chamber of either or both the first and second hydraulic devices to align the upper and lower platens.
- 7. A press comprising:a) an upper platen connected to an upper frame; b) a lower platen connected to a lower frame; c) spaced first and second hydraulic devices, each including: i) a cylinder; ii) a piston located in the cylinder defining a first and a second chamber in the cylinder, the piston sealingly engaging the cylinder and movable in the cylinder; and iii) a piston rod connected to the piston at one end thereof and extending through the second chamber; wherein the first and second chambers, each have an inlet/outlet for hydraulic fluid, and the second chamber of the first hydraulic device is in fluid communication with the first chamber of the second hydraulic device; wherein each of the hydraulic devices is connected at one end to the upper frame and at the other end to the lower frame, one of the connections being with the end of the piston rods extending from the second chambers; and wherein the hydraulic devices are operable by extension or retraction of the piston rods to shift, relatively, the upper or the lower platen toward or away from the other platen; d) a pump to pump hydraulic fluid into or from the first chamber of the first hydraulic device to cause the piston rods of both hydraulic devices to move and to shift the upper or lower platen relatively towards or away from the other platen; and e) a valve in fluid communication with the first chambers of the first and second hydraulic devices, wherein said valve is adapted to respond to a pressure in either of said first chambers measured by a sensing means upon a misalignment of said platens, and wherein said valve is adapted to selectively withdraw hydraulic fluid from the first chamber of either or both the first and second hydraulic devices to align the upper and lower platens.
- 8. A press comprising:a) an upper platen; and b) a lower platen; c) first and second hydraulic devices each including: i) a cylinder having a partition sealingly engaging the walls of the cylinder and located intermediate the ends of the cylinder, to define first and second chambers of the cylinder; ii) a first piston located in the first chamber and defining (a) a first sub-chamber between an end of the cylinder and the first piston and (b) a second sub-chamber between the first piston and the partition, the first piston sealingly engaging the cylinder and movable in the cylinder; iii) a second piston located in the second chamber and defining (c) a third sub-chamber between the partition and the second piston and (d) a fourth sub-chamber between the second piston and the other end of the cylinder, the second piston sealingly engaging the cylinder and movable in the cylinder; and iv) a piston rod connected to the first piston and the second piston and passing through and sealingly contacting the partition, and further extending from the fourth sub-chamber; wherein the first sub-chamber has an inlet for hydraulic fluid, the second sub-chamber has an outlet for hydraulic fluid, the third sub-chamber has an inlet/outlet for hydraulic fluid and the fourth sub-chamber has an inlet/outlet for hydraulic fluid; wherein the inlet/outlet of the third sub-chamber of one of the hydraulic devices is in fluid communication with the inlet/outlet of the fourth sub-chamber of the other hydraulic device; and wherein each of the hydraulic devices is connected at one end to the upper frame and at the other end to the lower frame, one of the connections being with the end of the piston rods extending from the fourth sub-chamber; and wherein each hydraulic device is operable by extension or retraction of the piston rods to shift, relatively, the upper or the lower platen toward or away from the other platen; d) a pump to pump hydraulic fluid into the first sub-chamber of each of the hydraulic devices e) a valve in fluid communication with the first sub-chambers of the first and second hydraulic devices, wherein said valve is adapted to respond to a pressure in either of said first sub-chambers measured by a sensing means upon a misalignment of said platens, and wherein said valve is adapted to selectively withdraw hydraulic fluid from the first sub-chamber of either or both the first and second hydraulic devices to align the upper and lower platens.
- 9. A press according to claim 8, wherein the valve is located externally of the cylinders in a hydraulic fluid line connected to each of the cylinders which communicates with a reservoir of hydraulic fluid.
- 10. A press according to claim 8, wherein the valve is located externally of the cylinders in a hydraulic fluid line which communicates between the hydraulic devices.
- 11. A press according to claim 8, wherein the valve is actuated in response to a change in a total volume of the hydraulic fluid in the hydraulic devices.
Priority Claims (1)
Number |
Date |
Country |
Kind |
PO7106 |
Jun 1997 |
AU |
|
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/AU98/00401 |
|
WO |
00 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO98/55289 |
12/10/1998 |
WO |
A |
US Referenced Citations (14)