PRESS PAD AND METHOD FOR PRODUCING THE SAME

Abstract

A press pad for a hydraulic heating press arrangement, the press pad including a fabric, wherein the fabric is formed by warp threads in a warp direction and weft threads in a weft direction, wherein the warp threads and the weft threads are woven together to form the fabric, and wherein functional threads run in the warp direction or in the weft direction and are connected with the fabric so that a thickness of the fabric in an effective portion of the functional threads differs from a thickness of the fabric outside of the effective portion of the functional threads.

Claims

1. A press pad for a hydraulic heating press arrangement, the press pad comprising: a fabric, wherein the fabric is formed by warp threads in a warp direction and weft threads in a weft direction, wherein the warp threads and the weft threads are woven together to form the fabric, and wherein functional threads run in the warp direction or in the weft direction and are connected with the fabric so that a thickness of the fabric in an effective portion of the functional threads differs from a thickness of the fabric outside of the effective portion of the functional threads.

2. The press pad according to claim 1, wherein at least a portion of the functional threads is formed by thickening threads so that the thickness of the fabric in the effective portion of the functional threads is increased relative to the thickness of the fabric outside of the effective portion of the functional threads.

3. The press pad according to claim 1, wherein at least a portion of the functional threads is sewn or woven onto the fabric or sewn or woven into the fabric.

4. The press pad according to claim 1, wherein a majority of the warp threads is formed by metal or brass.

5. The press pad according to claim 1, wherein a majority of the functional threads that are arranged in the warp direction has a diameter between 0.1 mm and 0.3 mm.

6. The press pad according to claim 1, wherein a majority of the weft threads is formed by an elastomeric material or silicone, and wherein a diameter of a respective weft thread is between 1.5 mm and 1.6 mm.

7. The press pad according to claim 1, wherein a majority of functional threads in the warp direction of the fabric is formed by thickening warp threads that are sewn or woven onto the fabric in the warp direction.

8. The press pad according to claim 1, wherein a majority of the functional threads is formed by thickening weft threads in the weft direction of the fabric, wherein the thickening weft threads are woven into the fabric, and wherein a diameter of the thickening weft threads is greater than a diameter of the weft threads.

9. The press pad according to claim 8, wherein the thickening weft threads are woven into the fabric so that the weft threads are omitted at weave in locations of the thickening weft threads so that a total thread count of all the weft threads and the thickening weft threads remains constant.

10. The press pad according to claim 1, wherein at least a portion of the functional threads or thickening warp threads that run in the warp direction are made from an aramid or a para aramid.

11. The press pad 1 according to claim 1, wherein at least a portion of the functional threads, or the thickening weft threads that run in the weft direction are made from silicon, and wherein a diameter of a respective functional thread is at least 1.70 mm.

12. The press pad according to claim 1, wherein the functional threads are arranged in a non-uniform distribution.

13. A method for producing a press pad for a hydraulic heating press arrangement, the method comprising: predetermining a design of a press plate that is configured to impress a press blank in the hydraulic heating press arrangement wherein the press plate includes a press relief that includes a structure, so that a surface structure is producible in the press blank that corresponds to the press relief by impressing the press plate into a surface layer of the press blank; producing the press pad adapted to dimensions of the press plate, wherein warp threads and weft threads are woven into a fabric of the press pad, wherein the press pad is produced as a function of a predetermined design of the press plate so that a thickness of the fabric is adapted at least in portions of the press pad that correspond to high portions of the press relief, wherein functional threads are connected with the fabric so that the thickness of the fabric in effective portions of the functional threads differs from the thickness of the fabric outside of the effective portions of the functional threads.

14. The method according to claim 13, wherein the press pad and the press plate are connected in a force transferring manner so that relative movements between the effective portions of the functional threads of the press pad and corresponding portions of the press relief are at are substantially prevented or entirely prevented.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The invention is subsequently described based on an embodiment with reference to drawing figures, wherein:

[0030] FIG. 1 illustrates a cross-sectional view of a heating press arrangement that is configured with a press pad according to the invention;

[0031] FIG. 2 illustrates a top view of a design of a surface structure of a press blank;

[0032] FIG. 3 illustrates a top view of an alternative design of a surface structure of a press blank;

[0033] FIG. 4 illustrates a schematic representation of a top view of a press pad according to the invention;

[0034] FIG. 5 illustrates a schematic cross-sectional view of a press pad according to the invention overlaying a press relief of an associated press plate;

[0035] FIG. 6 illustrates an additional cross-sectional view according to FIG. 5; and

[0036] FIG. 7 illustrates another cross-sectional view according to FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

[0037] An embodiment that is illustrated in FIGS. 1-7 relates to a press pad 1 according to the invention that is installed in a heating press arrangement. The press pad 1 that is formed by a fabric 2 is being used in combination with an associated press plate 16 for processing a press blank 17. The press pad 1 is arranged between a heating press 18 of the heating press arrangement 15 and the press plate 16, so that a force transmission is provided between the heating press 18 and the press plate 16 using the press pad 1. The press pad 1 is used for making forces between the heating press 18 and the press plate 16 more uniform so that the press plate 16 is evenly loaded by a pressure force over an entire surface of the press plate wherein the pressing force is provided by the heating press 18.

[0038] In the illustrated embodiment the press plate 16 includes a press relief 14 that facilitates pressing a surface structure 20 into the press blank 17. The press relief 14 is typically etched into a surface of the associated press plate 16 so that a structured surface is provided. FIGS. 2 and 3 illustrate how a design of a surface structure 20 of a press blank 17 can be configured wherein the configuration of the press relief 14 of an associated press plate 16 has to follow this desired design.

[0039] This is caused by the fact that the surface structure 20 is only caused by the configuration of the press relief 14 which is a negative image of the surface structure 20. The press relief 14 of the press plate 16 is pressed into a surface layer of a press blank 17 during the pressing cycle by the heating press 15 so that indentations are fabricated in the surface layer of the press blank 17 wherein the indentations are complementary to the protrusions of the press relief 14. In particular, when replicating naturally grown structures that are intended to imitate surface structures e.g. of wood materials, it is important that the surface structure the respective press blank 17 includes indentations with different configurations. It is particularly important to provide very deep impressions in the respective press blank 17 since these would also be provided in a natural material. A deep impression in the press blank 17 requires a high portion 19 in the press relief 14 of the press plate 16. In a high portion 19, the press relief 14 protrudes rather far beyond a press plate plane of the press plate 16.

[0040] Impressing the high portions 19 into the surface layer of a respective press blank 17 requires a rather high pressing force that has to be transferred to the press plate 16. The reaction force that is caused by the surface layer and that impacts the press plate 16 can cause the press plate 16 to slightly deform during the pressing cycle so that the impression of the high portions 19 into the surface layer is not caused in the same manner as in portions of the press relief 14 that have less definition or height. This has the effect that the surface structure 20 of the finished press blank 17 is not configured in the desired manner according to the intended design since the portions of the press blank 17 that shall have rather deep impressions are not configured as intended.

[0041] In order to prevent local escapement of the press plate 16 in the high portions 19 of the press relief 14 during the pressing process the press pad 1 is configured according to the invention with functional threads 7. The functional threads 7 are configured in the illustrated embodiment as thickening threads 8 that increase a local thickness 10 of the fabric 2, thus introducing the thickening threads 8 causes the press pad 1 or its fabric 2 to have a thickness 9 in an effective portion 21 of the thickening threads 8 wherein the thickness 9 is increased over a thickness 10 of the fabric 2 outside of an effective portion of the thickening threads 8. Thus, the fabric 2 is less compressible in the respective effective portion 21 of one or plural thickening threads 8 which prevents the local escapement of the press plate 16 towards the heating press 18 in the manner described supra. This has the consequence that a reliable impression of the press plate 16 into the press blank 17 is also provided in portions of the press plate 16 where the structure of the press relief 14 includes corresponding high portions 19.

[0042] FIGS. 2 and 3 show in which portions the surface structure 20 of the respective press blank 10 is configured particularly deep and how effective portions 21 for functional threads 7 are provided in the press pad 1 individually adapted to the design. The embodiment according to FIG. 3 relates to a press blank 17 that is provided with a plurality of gaps 22. In this embodiment individual press elements are produced in a single pressing cycles that are separated from each other by gaps 22. In the portions of these gaps 22 the associated press plate 16 includes very pronounced high portions 19 that are configured to impress at least the surface layer of the press blank 17 deep enough so that the finished press blank 17 includes the gaps 22 configured as particularly pronounced indentations. The finished press blank 17 can then be cut apart along the gaps 22 so that individual press elements are produced. The press pad 1 according to the invention that is adapted to a corresponding press plate 16 thus includes functional threads 7 in effective portions 21, in particular thickening threads 8 that are arranged at the press pad 1 at locations that coincide with the high portions 19 of the press plate 16 that in turn create the gaps 22 in the press blank 17. Accordingly the fabric 2 according to the invention a respective press pad 1 is adapted individually to a design of a respective press plate 16 or a desired design of a surface structure of a respective press blank 17 wherein the press plate 16 and the associated press pad 1 jointly form a functional unit where the advantageous effect that is obtained by introducing the functional threads 7 is only obtained in combination with the individually associated press plate 16. Accordingly it is provided according to the invention to individually adapt a respective press pad 1 to a predetermined design of a surface structure 20 of a press blank 17, wherein the adaptation is provided according to the invention by connecting the functional threads 7 with a remainder of the press pad. The press plate 16 and the press pad 1 are advantageously connected with one another in a force transferring manner so that relative movements between both components are prevented at least essentially in a direction of the press plate plane.

[0043] A fabric 2 according to the invention that is illustrated in FIG. 4 is formed in a known manner by warp threads 3 and weft threads 4 that are connected with one another. In the illustrated embodiment the fabric 2 includes a circumferential edge portion 5 and a center portion 6 that is enveloped by the circumferential edge portion 5. In the illustrated embodiment the fabric 2 includes a plurality of functional threads 7 in a center portion 6 wherein a portion of the functional threads 7 is oriented in the warp direction and the other portion of the functional threads 7 is oriented in the weft direction of the fabric 2. In this embodiment all functional threads 7 are formed by thickening threads 8 that are formed by thickening warp threads 11 in the warp direction and by thickening weft threads 12 in the weft direction. As a matter of principle it is secondary for the invention how the functional threads 7 are connected with the remainder of the fabric 2. By the same token it is particularly advantageous to apply thickening warp threads 11 that extend in the warp direction to the fabric 2 locally, sew them on or weave them on. This achieves the effect that the thickness 9 of the fabric 2 is increased in the effective portion 21 of the thickening warp threads 11 over the thickness 10 of the fabric 2 outside of the effective portion 21. This is illustrated in FIG. 5. The schematic cross section of the fabric 2 is illustrated together with a local detail of an associated press plate 16 with an individual press relief 14 that includes a high portion 19. The thickening warp threads 11 are arranged individually adapted to the press relief 14 so that the effective portion 21 where the thickening warp threads 11 cause the desired increase of the thickness 9 of the fabric 2 coincides with the high portion 19 of the press relief 14. This achieves the effect described supra that the press pad 1 is less compressible in this portion of the press plate 16 where the greatest resistance against the desired impression into the surface layer of the press blank 17 occurs during a pressing cycle so that an escapement of the press plate 16 caused by the reaction force in a direction towards the heating press 18 is counter acted.

[0044] Another embodiment of a non-uniform introduction of functional threads 7 is illustrated in FIG. 6. Here the functional threads 7 are configured to function as thickening threads in the warp direction of the fabric 2 and thus formed by thickening warp threads 11. The schematic detail of the fabric 2 is selected larger than in the illustration according to FIG. 5 wherein the press relief of the illustrated press plate 16 includes a plurality of high portions 19. The thickening warp threads 11 are positioned in the fabric 2 individually and in a non-uniform arrangement so that their effective portions 21 coincide with the high portions 19 of the press relief 14. This way the intended thickening of the fabric 2 is provided for all high portions 19.

[0045] The thickening warp threads 11 are thus formed as additional threads so that a total thread number in the warp direction of the fabric 2 is larger when introducing the functional threads 7 compared to a total number of threads without the functional threads 7. Thickening warp threads 11 are configured by a para aramid in the illustrated embodiment and applied to the remaining fabric 2. Selecting para aramid is advantageous in that para aramid has low heat conductivity along with advantageous mechanical properties so that thermal energy provided by the heating press 18 is transferred less to the press plate 16 and thus to the press blank 17 in effective portions 21 of the thickening warp threads 11 than in portions of the fabric 2 that does not include the thickening warp threads 11. This reduced heat conductivity of the press pad 1 in the effective portions 21 of the thickening warp threads 11 causes the surface layer of the press blank 17 that is typically made from melamine resin to cure more slowly so that it remains formable over a longer time period. This means it has a comparatively low viscosity. The increase of viscosity that occurs during curing of the surface layers of the press blank 17 is consequently slowed down in the effective portions 21 of the thickening warp threads 11. The deep portions of the surface structure 20 of the press blank 17 can thus be formed during a longer operating time.

[0046] Last not least, FIG. 7 illustrates a schematic cross section of the fabric 2 that shows the weft threads 4 of the fabric 2. The fabric 2 includes functions threads 7 in the weft direction that are formed by thickening threads 8. Since these thickening threads run in the weft direction the thickening threads 8 are formed by thickening weft threads 12. Differently from the warp direction described supra the thickening weft threads 12 are not applied to the fabric 2 in the illustrated embodiment, thus not sown on or woven on but woven directly into the fabric 2 at weave in locations 13. In particular at locations where the fabric 2 includes the thickening weft threads 12 the normal weft threads 4 are not provided at these locations. This has the effect that a total thread counts of the fabric 2 is not changed by introducing the thickening weft threads 12.

[0047] The diameter 23 of the thickening weft threads 12 is increased in the illustrated embodiment over the diameter 24 of the remaining weft threads 4, so that the thickness 9 of the fabric 2 in the effective portion of the thickening weft threads 12 is increased over the thickness 10 outside of the effective portion 21. The technical effect of this configuration is identical to the technical effect that is achieved by the thickening described supra that is achieved by the thickening warp threads 11. The diameter 23 of the thickening weft threads 12 is 1.65 mm in the illustrated embodiment whereas the diameter 24 of the remaining weft threads 4 in the illustrated embodiments is 1.5 mm. The thickening weft threads 12 are formed by silicone and thus their material corresponds to the material of the remaining weft threads 4.

REFERENCE NUMERALS AND DESIGNATIONS

[0048] 1 Press pad

[0049] 2 Fabric

[0050] 3 Warp thread

[0051] 4 Weft thread

[0052] 5 Edge portion

[0053] 6 Center portion

[0054] 7 Functional thread

[0055] 8 Thickening thread

[0056] 9 Thickness

[0057] 10 Thickness

[0058] 11 Thickening warp thread

[0059] 12 Thickening weft thread

[0060] 13 Weave in location

[0061] 14 Press relief

[0062] 15 Heating press arrangement

[0063] 16 Press plate

[0064] 17 Press blank

[0065] 18 Heating press

[0066] 19 High portion

[0067] 20 Surface structure

[0068] 21 Effective portion

[0069] 22 Gap

[0070] 23 Diameter

[0071] 24 Diameter