Plastic article or earthenware shaping or treating: apparatus – Press forming means – press reshaping means – or vulcanizing... – Cooperating endless belts
Reexamination Certificate
1999-12-23
2001-11-27
Tolin, Michael A. (Department: 1733)
Plastic article or earthenware shaping or treating: apparatus
Press forming means, press reshaping means, or vulcanizing...
Cooperating endless belts
C156S583500
Reexamination Certificate
active
06322346
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a device for continuous production of plate-shaped products.
2. Description of the Prior Art
In the compression of materials which achieve the liquid phase or are softened during the compression process, accompanying strips are required, through which a lateral flowing away of the product is prevented. A lateral flowing away of the product would namely mean that the counter pressure drops in the product edge region and that an isobaric compression pressure no longer prevails there. A pressure decrease would set in toward the edge which further favors the flow process. A material flow of this kind would moreover lead to the respective design structure being disturbed in the product edge region and to this edge region thus becoming unusable.
A device for continuous production of plate-shaped products, which has co-moving strips of elastic material for the lateral closing off of the working gap of the described device, is known from EP 0484 735 A1. These strips are taken along via frictional locking and can contain reinforcement inlays. In practice, however, the resulting frictional locking is not sufficient in order to ensure the required exact positioning of the strips, in particular when a high internal pressure arises in the pressing gap as a result of the materials to be compressed.
A device for continuous production of plate-shaped products having accompanying strips is known from DE-A-29 23 036. In order to ensure that the accompanying strips withstand the internal pressure of the product and cannot be pressed away outwardly, the lower endless strip is provided with holders in this known device which are formed for example by bolts which are welded on or adhesively bonded on. The use of a holder of this kind is not only complicated and expensive, but it also brings about in particular the disadvantage that a width adjustment which may be required is not possible without further ado.
SUMMARY OF THE INVENTION
The object of the invention is to create an apparatus of the initially named kind in which, in a particularly simple and correspondingly economical manner, on the one hand the width of the working gap and thus of the product can be adjusted without problem through a corresponding displacement of the accompanying strips and on the other hand it is ensured that the accompanying strips exactly maintain their respective position during operation.
The object of the invention is satisfied in that the sealing strip has at least at one broad side which faces an endless strip a frictional surface which increases the adhesive friction between the flexible sealing strip and the endless strip and which is formed by a frictional layer which is provided with an abrasion means.
As a result of the increased adhesive friction which is achieved through the frictional surface, more complicated and expensive holders or the like can be dispensed with. It is nevertheless ensured that the accompanying strips maintain their respective position during operation. In addition the width of the working gap and thus the width of the product can where appropriate be adjusted without problem through a corresponding displacement of the accompanying strips. Through the accompanying strips, which are to be matched in their thickness to the material thickness, finally, any lateral flowing away of the starting material is prevented, so that an orientation-free structure is obtained for the respective product over the entire width region. The frictional surface is preferably formed by a frictional layer which is applied to the respective broad side of the sealing strip.
In an embodiment which is preferred in practice the frictional surface, when viewed transversely to the strip travel direction, ends at a distance from the gap-side edge of the flexible sealing strip, with the region between the frictional surface and the relevant endless strip being sealed off in the direction towards the working gap through the frictional-surface-less edge region of the flexible sealing strip at least under the action of a pressing force which is applied via the support surfaces. Through this it is excluded that liquid or softened material enters into the region between the frictional surface and the relevant endless strip, so that an ideal adhesion action is always provided for.
For achieving an ideal seal the flexible sealing strip may be matched at least at one broad side in the frictional-surface-less edge region with a sealing lip which extends in the strip longitudinal direction.
In an embodiment which is preferred in practice the flexible sealing strip has a frictional surface on only one broad side. In this case it is advantageous when the flexible sealing strip is provided with a sealing lip at least at the oppositely situated broad side.
In principle however the use of a flexible sealing strip which has at both broad sides in each case a sealing lip which extends in the strip longitudinal direction is also possible.
The frictional layer advantageously comprises a temperature resistant carrier layer which is connected to the flexible sealing strip and onto which the abrasion means is applied. This carrier layer can expediently be formed by a temperature resistant plastic mesh. The frictional layer thus also withstands higher compression pressures and correspondingly higher temperatures.
The abrasion means can for example contain sand material and/or the like. Alternatively or additionally, it can also contain corundum. In this case corundum which is bound in phenolic resin is preferably used.
The frictional layer is preferably adhesively bonded to the flexible sealing strip. A further required property of this flexible sealing strip is its temperature resistance and temperature change strength. The temperature resistance should reach to about 200° C. and the temperature change strength from about 200° C. to about 30° C.
The flexible sealing strip preferably consists of silicone rubber, polytetrafluorethylene (TFE) and/or the like, through which among other things it is achieved that the relevant accompanying strip can be released without problem from the product, which (is) for example a plastic flooring (or the like).
In order to ensure a permanent bonding between this frictional layer and the flexible sealing strip under the respective compression conditions at varying pressure and at varying temperature, this frictional layer is expediently adhesively bonded to the flexible sealing strip by a two component adhesive bonder, in particular a two component silicone rubber adhesive bonder.
As protection against a loosening of the abrasion means an adhesive bonder edge is expediently provided at the gap-side edge of the frictional layer.
Since the flexible sealing strip is as a rule subjected to a tensile stress, it is advantageous if it contains a reinforcement, which can for example consist of a glass fiber mesh. For protecting this reinforcement the gap-side edge of the flexible sealing strip can be provided with a covering which is preferably produced by a silicone rubber paste.
In an embodiment which is preferred in practice two endless accompanying strips are provided which in each case encircle the lower endless strip. In this it is advantageous if the upper side of the lower endless strip protrudes outwardly or is drawn forward beyond the upper endless strip in the direction opposite to the strip travel direction. Through this the starting material which is applied to this side experiences a definite lateral bounding.
The flexible sealing strip of a respective accompanying strip preferably has a frictional surface only on its broad side which faces the lower endless strip.
REFERENCES:
patent: 3462795 (1969-08-01), Hermanns
patent: 4105387 (1978-08-01), Ahrweiler
patent: 4573404 (1986-03-01), Held
patent: 4850848 (1989-07-01), Greten
patent: 5395576 (1995-03-01), Blauhut
patent: 5827460 (1998-10-01), Brentrup et al.
patent: 2923036A1 (1980-12-01), None
patent: 3928847A1 (1991-03-01), None
patent: 29622385U1 (1997-06-01), None
pat
Haupt Ulrich
Hoffmann Peter
Tolin Michael A.
Townsend and Townsend / and Crew LLP
Valmet Panelboard GmbH
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