Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B30—PRESSES
  • B30B—PRESSES IN GENERAL
  • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
  • B30B15/06—Platens or press rams
  • B30B15/061—Cushion plates

Definitions

• the invention relates to a press pad for use in laminating presses with a fabric which has a first group of parallel threads and a second group of parallel threads crossing the threads of the first group, the threads of the first group being made of metal or having a metal content, and wherein the threads of the second group consist of or have a proportion of rubber-elastic material, and wherein the threads of the first group crank around the threads of the second group.
• layer materials for example decorative chipboard coatings
• laminating presses which can be designed as low or high pressure floor presses or short cycle presses.
• Press pads are used which have the task of transferring the pressure over the entire surface and evenly to the material to be pressed.
• the press pads must be able to withstand high pressures and also the temperatures present in such presses, and they must be able to transfer the heat emanating from the press plates to the material to be pressed quickly and without major losses, i.e. to have a high thermal conductivity in this direction.
• Press cushions are known in the prior art which consist of a fabric which comprises two types of threads (EP 0 493 630 A1).
• the threads are made of metal or have a metal component in order to improve the heat transfer to the material to be pressed.
• Various proposals are made for the second group of threads, for example threads made of aromatic polyamide (EP 0 493 630 A1), made of silicone elastomer (DE 295 18 204 U1) or made of rubber, heat-resistant plastic monofilament or the like (EP 0 713 762).
• the invention is therefore primarily based on the task of creating a press cushion with better thermal conductivity. Another task is to improve dimensional stability and to provide a smooth surface.
• the thread density of the threads of the second group is so great that the threads of the first group pass between them only with compression of the rubber-elastic material of the threads of the second group.
• the free distance between the threads of the second group in the undeformed state, ie without compression of the rubber-elastic material is less, preferably at least 10% less than the thickness extension of the threads of the first group in one plane, which goes through the longitudinal axis of these threads and extends perpendicular to the plane of the press cushion.
• the basic idea of the invention is therefore to have a positive influence on the heat transfer by means of a special fabric geometry with a very high thread density in the threads of the second group.
• the improved heat transfer is achieved in that the threads of the first group are forced to pass very steeply between these threads due to the small distance between the threads of the second group. This results in short heat paths between the two surfaces of the press pad, with the result that the pressing of the material to be heated takes place much faster. This means that much shorter cycle times can be achieved and energy consumption is also lower due to the lower temperature difference.
• the threads of the first group dig into those of the second group with elastic compression of the rubber-elastic material of these threads, with the result that the threads do not slip against each other.
• the processing of the fabric, that is the internal wear is kept comparatively low.
• the dimensional stability in the direction of the threads of the first group is much better, even if the copper material which tends to shrink due to the formation of loops is used as the metal material.
• the thermal conductivity of which is only a third of that of copper and the material price is significantly higher than that of copper. Since copper can be used on the basis of the fabric structure according to the invention, the thermal conductivity also increases considerably as a result, and this at significantly lower costs.
• the threads are interwoven in such a way that the threads of the first group do not protrude beyond the plane formed by the outermost points of the threads of the second group, and are even better at a distance from this plane.
• This design has the advantage that the threads of the first group are protected against abrasion when handling the press cushion.
• the threads of the first group (metal threads) only come into contact with the adjacent surfaces of the press and the material to be pressed and then ensure good heat conduction when the laminating press is subjected to pressure.
• the thread density of the threads of the first group is so high that the area coverage is between 50 and 80%, preferably between 60 and 70%. This high thread density also promotes the thermal conductivity and thus the rapid heating of the pressed material.
• the threads have a weave with an even distribution of the cranks of the threads of the first group.
• the number of cranks of the threads of the first group should be on each side of the fabric are between 20 and 30 per cm 2 . This high density of the cranks also ensures good heat transfer across the surface.
• the rubber-elastic material has a Shore A hardness of 60 to 75. This hardness favors the storage of the threads of the first group and thus a firm tissue bond. In addition, the residual compressibility with this hardness is maintained for a long time.
• All materials which have rubber-elastic properties and which are able to withstand the temperatures in the presses are suitable for the rubber-elastic material. Silicone elastomers are particularly suitable. A foamed rubber-elastic material is recommended, preferably with a specific weight of 0.3 to 0.5 g / cm 3 .
• such metal materials should be used that have a high thermal conductivity.
• copper or strength-modified copper alloys are particularly suitable for this. Due to the firm weave, the tendency of copper threads to shrink is counteracted, so that despite the use of this problematic material, no significant shrinkage could be determined. In this way, the high thermal conductivity and the low price of this material can be used for the press pad according to the invention.
• the use of non-annealed copper (hard copper) is particularly advantageous because it has a high strength. Annealed copper (soft copper) is also an option.
• threads of the first group have a plastic core thread, which is surrounded by at least one metal wire, and preferably in such a way that the plastic core thread is completely covered by the metal wire or wires.
• the cover is preferably done by wrapping at least one metal wire, expediently a plurality of metal wires one above the other, or by stranding metal wires.
• the stranding or wrapping of the metal wire or wires creates, in contrast to twisting, an almost circular thread, which forms a larger contact surface on the top and bottom of the press pad and thus good heat transfer from the press plates to the material to be pressed is achieved.
• Heat-resistant plastics for example aramids, or monofilaments made of PPS, PEK, PEEK or the like or glass fiber threads are suitable for the plastic core thread.
• the invention further provides that threads of the second group are surrounded on the outside with at least one metal wire, and preferably here also such that the threads of the second group are completely covered on the outside with the metal wire or wires.
• This has the advantage that the threads of the second group also transfer heat promote, but do not lose their cushioning properties due to the proportion of rubber-elastic material.
• the threads of the second group are also preferably wrapped here by stranding or wrapping.
• the threads of the second group can consist entirely of rubber-elastic material, for example a silicone elastomer. However, better strength is achieved if these threads have a core thread which is surrounded by an extruded shell made of rubber-elastic material.
• the core thread can have a central thread, for example made of aramid, glass fibers, metal, etc., around which the metal wires are stranded or wound.
• the stranded metal wires should be partially S-shaped and partially Z-shaped, this advantageously being done alternately. This effectively prevents the press cushion from "wandering" in the press.
• the threads of the second group should have a diameter of at least 1 mm, preferably of at least 1.5 mm. They then remain essentially stretched within the fabric and, together with their high thread density in relation to the thickness of the threads of the first group, promote a pronounced cranking of these threads.
• the threads of the first group should have a diameter of at least 0.15 mm, which can go to 0.3 mm.
• the press pad 1 shown in FIGS. 1 and 2 is designed as a single-layer fabric 2 with longitudinal threads extending in the warp direction - denoted by 3 for example - and transverse threads extending in the weft direction - denoted by 4, for example.
• the transverse threads 4 are essentially stretched, i.e. they are not significantly pushed out of the press cushion plane by the integration with the longitudinal threads 3, while the longitudinal threads 3 wrap around the transverse threads 4 and thereby form pronounced offsets on the top and bottom, for example, designated 5, 6, which develop during operation under the action of pressure flatten and which are connected between the transverse threads 4 by intermediate sections - designated 7 by way of example. This results in a meandering course of the longitudinal threads 3.
• a longitudinal thread 3 is shown in more detail in FIG. It has a twisted core thread 8 made of aramid, around which six metal wires - designated 9 by way of example - are twisted according to the type of stranding, in such a way that the core thread 8 is completely enveloped by the metal wires 9. This results in a very closed and relatively smooth surface of the longitudinal thread 3, which ensures good contact with the press plates and the material to be pressed.
• the longitudinal thread 3 has a diameter of 0.2 mm.
• the cross thread 4 shown enlarged in FIG. 4 has a core thread 10 of 0.2 mm diameter, which consists of a central thread 11 made of aramid and six metal wires — designated 12, for example — the metal wires 12 being stranded around the central thread 11.
• the metal wire 12 consists of non-annealed copper (hard copper), whereby a high strength is achieved.
• the core thread 10 is surrounded by an extruded-on elastomer sleeve 13 made of a silicone elastomer. This results in a diameter for the transverse threads 4 of 1.5 mm.
• the thread density of the transverse threads 4 is such that the distance between the transverse threads 4 without woven-in longitudinal threads 3, that is to say in the undeformed state, is less than their diameter, that is to say less than 0.2 mm.
• the longitudinal threads 3 thus dig into the elastic material of the elastomer sleeve 13 of the transverse threads 4. This not only has the advantage that the longitudinal threads 3 cannot shift in the direction of the longitudinal axes of the transverse threads 4, but rather force the longitudinal threads 3 to form steep intermediate sections 7.
• Figure 6 shows a transverse thread 15 for a press pad, not shown here.
• the cross thread 15 is suitable to also be used in the press pad 1 according to FIGS. 1 and 2. It has an elastomer core 16 made of a silicone elastomer, which - which is not shown in more detail here - surrounds a core thread which is constructed in the same way as in the cross thread 4.
• Metal wires - designated 17 by way of example - are stranded around the elastomer core 16. After completion of the stranding process, the entire area of the elastomer core 16 is surrounded by the metal wires 17, which thus form a gapless metal sheath.
• the cross thread 15 is therefore suitable for improving the heat transfer through a press pad manufactured with it, be it as the only metal threads, be it in addition to metal longitudinal threads, or be that the longitudinal threads are also formed in the same way as the transverse threads 15.
• FIG. 7 shows a transverse thread 18 which can be used as a replacement for or in combination with the transverse thread 15 according to FIG. 6 in a press cushion. It also has an elastomer core 19 made of a silicone elastomer, which — which is not shown in more detail here — surrounds a core thread that is constructed in the same way as in the cross thread 4.
• a metal wire 20 is wound around the elastomer core 19, specifically in such a way that it surrounds the elastomer core 19 over the entire area and thus a gapless metal sheath is formed. It is expedient that the metal wire 20 is surrounded by another metal wire in the reverse winding direction, so that there is then a two-layer metal sheath. This ensures that a complete covering of the elastomer core 19 is ensured even in bends.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Woven Fabrics (AREA)
• Mechanical Treatment Of Semiconductor (AREA)
• Bipolar Transistors (AREA)
• Liquid Crystal (AREA)
• Laminated Bodies (AREA)
• Printing Plates And Materials Therefor (AREA)
• Surface Heating Bodies (AREA)
• Building Environments (AREA)
• Encapsulation Of And Coatings For Semiconductor Or Solid State Devices (AREA)
• Confectionery (AREA)
• Apparatuses For Bulk Treatment Of Fruits And Vegetables And Apparatuses For Preparing Feeds (AREA)
• Polishing Bodies And Polishing Tools (AREA)
• Presses And Accessory Devices Thereof (AREA)
• Magnetically Actuated Valves (AREA)
• Braking Systems And Boosters (AREA)
• Finger-Pressure Massage (AREA)
• Absorbent Articles And Supports Therefor (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=8049522

Family Applications (1)

Country Status (10)

Families Citing this family (19)

Family Cites Families (6)

• 1997
  • 1997-12-05 DE DE29721495U patent/DE29721495U1/de not_active Expired - Lifetime
• 1998
  • 1998-10-31 DE DE59809559T patent/DE59809559D1/de not_active Expired - Lifetime
  • 1998-10-31 AT AT98120719T patent/ATE249334T1/de active
  • 1998-10-31 EP EP98120719A patent/EP0920983B1/de not_active Expired - Lifetime
  • 1998-10-31 DK DK98120719T patent/DK0920983T3/da active
  • 1998-10-31 ES ES98120719T patent/ES2203869T3/es not_active Expired - Lifetime
  • 1998-10-31 PT PT98120719T patent/PT920983E/pt unknown
  • 1998-11-24 CZ CZ19983821A patent/CZ294633B6/cs not_active IP Right Cessation
  • 1998-11-30 HU HU9802776A patent/HU219898B/hu not_active IP Right Cessation
  • 1998-12-04 SK SK1668-98A patent/SK284583B6/sk not_active IP Right Cessation
  • 1998-12-04 PL PL98330109A patent/PL188168B1/pl not_active IP Right Cessation

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