Presses – Automatic or material triggered control – Of parallelism of platens
Reexamination Certificate
2000-02-29
2003-03-04
Sipos, John (Department: 3721)
Presses
Automatic or material triggered control
Of parallelism of platens
C100S25800A, C100S25800A
Reexamination Certificate
active
06526879
ABSTRACT:
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
Huynh Louis
Pryda (Aust.) PTY LTD
Sipos John
LandOfFree
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