Adhesive bonding and miscellaneous chemical manufacture – Surface bonding means and/or assembly means therefor – Presses or press platen structures – per se
Reexamination Certificate
2003-04-07
2004-06-22
Sells, James (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Surface bonding means and/or assembly means therefor
Presses or press platen structures, per se
C156S358000, C156S580000, C156S583100
Reexamination Certificate
active
06752901
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a coating press for sheet-like work-pieces. The coating press contains a press frame with press cylinders, an upper and a lower press platen, at least one pressure plate, a pressure compensating cushion disposed between the press platen and the pressure plate, and a press controller.
A plate press for the coating of plate-shaped work-pieces, contains the press frame with press cylinders, the upper and a lower press platen, the pressure plate and the pressure compensating cushion disposed between the press platen and the pressure plate. Such a plate press is known, Published, Non-Prosecuted German Patent Application DE 199 37 694 A1, in which the pressure compensating cushion contains a diaphragm plate and a compensating plate, solid in the cold state, between the diaphragm plate and a heating plate of the plate press. The compensating plate forms, at the pressing temperature, a liquid pressure pad having a predetermined viscosity and thermal conductivity. The known press is intended to have the effect that, with respect to the pressure plate, there is established a homogeneous pressure distribution and minimized pressure plate wear which is usually caused by the deformations of the press platens as a consequence of thermal stresses and by unevennesses of the work-pieces or by their thickness tolerances generated during the manufacturing process.
One disadvantage of the known solution is that the entire press requires fundamental actions and change in order to integrate the pressure compensation cushion into the press platens, this being extremely inefficient. Furthermore, by virtue of such a special construction, the versatility of a press thus equipped is considerably restricted. Also, the diaphragm plate has to be made relatively thick, so as not to bulge out locally in the case of the supporting zones or anchoring heads lying far apart from one another, with the result that the diaphragm plate cannot mate with the surface of the work-pieces. There is, furthermore, a risk that, in the case of very thin and very hard work-pieces to be coated, there will be formed on the work-piece surfaces nests of approximately the size of the area of a hand, which are not completely pressed, so that such work-pieces are only second-rate or even rejects.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a coating press for sheet-like work-pieces that overcome the above-mentioned disadvantages of the prior art device of this general type, which, along with reduced maintenance intensity, delivers a constantly high-grade working result and which, in particular, is to be capable of compensating small-area unevennesses of the work-pieces. Furthermore, the versatility of the coating press is to be maintained as far as possible.
With the foregoing and other objects in view there is provided, in accordance with the invention, a coating press for sheet-like work-pieces. The coating press contains a press frame, press cylinders supported by the press frame, an upper press platen connected to the press cylinders, a lower press platen supported by the press frame, at least one pressure plate, and at least one pressure compensating cushion disposed between the upper press platen or the lower press platen and the pressure plate. The pressure compensating cushion is a hydraulic cushion having a lateral edge closure, a hydraulic medium, and covers including an upper cover and a lower cover. The upper and lower covers along with the lateral edge closure define a pressure-tight inner space filled with the hydraulic medium. A press controller is further provided. Since the pressure compensating cushion is configured as a hydraulic cushion that has an upper cover, a lower cover and a lateral edge closure, and since the covers and the lateral edge closure surround a pressure-tight inner space which is filled with a hydraulic medium, a pressure compensating cushion is made available which can be exchanged in a simple way for a conventional pressure compensating cushion, without substantial actions on the construction of an existing coating press becoming necessary for this purpose. The hydraulic cushion may also advantageously be used in other types of press, such as multistage presses or film-strip presses. The coating press equipped with such a hydraulic cushion allows isobaric pressure distribution to the work-piece, in spite of thermally induced or weight-induced or pressure-induced bending of the press platens or in spite of the large-area thickness tolerances, caused by the grinding process, of the work-pieces to be coated, of about {fraction (1/10)}-{fraction (3/10)} mm. By virtue of the large-area, close configuration of the supporting profiles, in conjunction with an extremely thin work-piece-side cover, even small-format unevennesses of the work-pieces, which occur, for example, due to faults during the process of grinding chipboards, can be ironed out.
It is advantageous, furthermore, that such a coating press allows a continuous change of format of the work-piece in terms of length and width. Moreover, because of the matability of the work-piece-side cover and the isobaric pressure distribution achieved thereby, the work can be carried out with lower specific pressures, so that, in the case of a new construction of a coating press, the frame plates of the press frame, the press platens, the heating plates and the press cylinders can be produced with lighter weight. The known conventional press cushions can be dispensed with completely or else continue to be used in a substantially thinner form for a much longer period of time. In the case of new coating presses, even counter heating of the press platens may be dispensed with. It could be used, for example, simply for better heat distribution. The extra costs that the hydraulic cushion according to the invention generates are then compensated merely by virtue of the absence of manufacturing costs, piping, regulating systems and control for the counter heating.
Further advantages for the manufacturer using a coating press are reliable production, even in the event of stoppages in the process cycle, and the absence of costs due to the press cushion, the absence of service life monitoring, of the necessary cushion changes and also of pressing-in operations.
The hydraulic cushion can be pressurized under a press platen in a similar way to a normal pressure compensating cushion and can consequently be retrofitted in a simple way even on existing presses.
A further essential advantage is that the hydraulic cushion is not tied to any particular press temperature. It may also be used at temperatures of below 100° C. or even manage completely without heating. The cushion can therefore be used not only in short-cycle presses, what may be referred to as short cycle (SC) plants, but also in all other types of press.
According to a particularly preferred embodiment of the invention, on the covers of a hydraulic cushion are provided inwardly directed supporting profiles which are connected to one another in a form-fitting manner with mutual play in the vertical direction of the covers, so that a maximum travel of the two covers in relation to one another is fixed via the play. This measure prevents the situation where the internal pressure within the hydraulic cushion that occurs due to the surface pressure bulges out where the cushion is not supported by a work-piece or the situation where the pressure plate may bend away at the edge of the work-piece. In order to ensure that the surface of the cover facing the work-piece can nevertheless mate completely with the surface of the latter in a particularly advantageous way, the cover is made thinner than the cover facing away from the work-piece.
An embodiment is particularly advantageous here in which the supporting profiles of both covers have the same height, so that the profiles of one cover bear on the inside on the other cover and thus make available a large-area support of the covers which, in the event of
Greenberg Laurence A.
Heinrich Wemhoener GmbH & Co. KG
Mayback Gregory L.
Sells James
Stemer Werner H.
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