AU682858B2 - Surface treatment of building elements - Google Patents

Description

P/:00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

TO BE COMPLETED BY APPLICANT

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S.

Name of Applicant: Actual Inventor(s): Address for Service: A J BATES LIMITED ROBERT EDWARD BATES JOHN R.G. GARDNER PO BOX 443 MUDGEERABA QLD 4213 Invention title: SURFACE TREATMENT OF BUILDING ELEMENTS s.

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55 o *oosc The following statement is a full description of this invention, including the best method of performing it know to me:a This invention concerns a process for embossing panels, linings, boards, strips and the like as used in building, apparatus for carrying out the process and the embossed product therefrom.

The construction industry uses large quantities of board for lining, for example gypsum plasterboard and md fibreboard which are soft and facing board, for example laminate and fibro cement panels which are harder. The latter are sprayed with two pot synthetic coatings in order to provide a smooth, hard hygienic finish. Decorative surface effects such as reproducing a coriaceous finish increase the thickness of the product unevenly. Other decorative finishes are confined to surface effects, such as marbling. Fibro 15 cement panels are only 5-10mm thick.

Attempts to modify the surface appearance of a harder So. more brittle panel by reducing its thickness in selected areas generally cause the panel to split during subsequent handling. There is sometimes a need for a panel which simulates tile, for example, in commercial kitchens. Cutting grooves in such panels See.

exposes the ends of cut fibres and this changes the oe uptake of subsequent coatings or leaves raw cut fibres which are a dirt and moisture trap.

25 Pressing a planar die into the face of the panel in S" order to impose a grid or tile pattern thereon is unsuccessful because the variation in thickness across the area of the panel leads the eye to perceive tiles of varying thickness This invention addresses the problem.

The process aspect of the invention provides a method i i -I of embossing a substrate of the type as herein defined using an embossing means having a series of stationary side by side tools mounted adjacent a stationary work surface being capable of embossing to a constant depth across a surface of the substrate including contacting the substrate surface with an embossing tool with a pressure which is great enough to emboss but insufficient to render the panel susceptible to splitting.

The embossing tool may be a wheel for indenting a groove. There may be a plurality of side by side wheels enabling parallel grooves to be indented. The wheel circumference may be profiled to to give bevelled arcuate, V-shaped or other cross-sections to the 15 embossments. The wheel may travel at a different speed i to the feed speed of the panel so that the indentation appears matt or shiny.

The wheel n.ay carry one or more embossing dies so that a repeat intermittent pattern is reproduced rather than a continuous groove. The embossment may be 0.5,0.6,0.7,0.8,0.9,1.0,1.1,1.2,1.3,1.4,1.5,1.6,1.7 or 1.8mm deep. A groove of 0.5mm is easily visible.

The apparatus aspect of the invention provides .00. apparatus for embossing a substrate of the type .0 25 described comprising an embossing station to which workpieces are admitted and removed, embossing means and means for providing relative movement between the embossing means and the workpiece.

The embossing means may be a series of stationary tools mounted adjacent the station work surface, being capable of embossing to a constant depth across the surface of the substrate. This feature is important because the eye easily picks up small imperfections in the finished product. This is possible because the panel surface is smnooth and light reflecting.

The tools may each be held in a stiff mount extending from a rigid bridge so as to control any flexing of the station during embossing when the sum of the forces on each tool is resisted by the bridge. The embossing means may utilise fluid pressure to apply the embossing force. When multiple tools are used, equal force is thus applied and equal depth of embossment results despite fluctuations in panel thickness.

The substrate may be 2400 x 1200mm panels of gypsum plasterboard, fibrocement, fibreboard especially mdf and laminates. Fibro cement panels 5-10mm thick may be 15 embossed to 0.5-1.8mm without splitting. Grooves may be 1,2,3,4,5,6,7,8,9 or 10mm wide. Softer substrates such as dado strip made of mdf may be embossed with Swider and deeper grooves because they are less prone to splitting.

20 Embossing pressures range from 15-100psi preferable 85psi. Plasterboard requires 15psi, VILLABOARD (RTM) needs 35psi and laminates need The machine described above relies upon a reciprocating feed. The invention also provides a machine with 0 S 25 rotary feed. The machine may comprise an anvil roll disposed normally to the direction of panel feed, a series of embossing wheels providing a series of nips along the anvil roll circumference and a guideway located tangentially to the nip and parallel to the feed direction.

The anvil roller is preferably 500-600mm in diameter.

Ine The embossing rolls may be 250-350mm in diameter.

Larger wheels give a groove of better appearance and there is less risk of damaging the panel.

Two embodiments of the invention are now described with reference to the accompanying drawings in which: FIG. 1 is a diagrammatic sectional elevation of an embossing machine; FIG. 2 is an end view of the edge of the embossing wheel bearing on a panel fragment; and FIG. 3 is a side view of a self feed version.

Referring now to FIG. 1 a machine for embossing 1200x2400mm fibrocement panels 2 has a smooth, steel work surface 4 fixed to a steel I-beam 6 which extends across the length of the panel. Likewise a multiple 15 toolbridge 8 is fixed to an I-beam 10 which spans the work surface. The two beams 6,10 are connected by pillars 12 so that they define a 2400x450mm window 14.

A series of embossing assemblies extend downwards from the toolbridge, each having a pivoted arm 16 carrying 0 20 an axle with a pair of 150mm dia. Steel embossing wheels 18 on each side of the arm. The arms trail but are maintained at the correct height by an inclined air ram 20 connected between he toolbridge and the arm 16.

The rams are set up for equal pressure operation.

Panels 2 are presented to the work surface on a feed table 22. The feed table has slots 24 lying parallel to the feed direction. An endless conveyor 26 beneath the feed table has lugs 28 which project above the table surface and engage the rear edge of a panel feeding the latter squarely toward the wheels between upright guides 30. The feed speed must be constant in order to achieve a uniform appearance in the finished i j---i product. The leading edge of the panel moves into the rubber collets of a pneumatic tractor 34 in order to complete the feed when the conveyor 26 ceases pushing.

The panel is put through the same machine at ninety degrees to obtain a tile effect.

In FIG. 2 the wheel edge 36 is seen projecting into the surface of panel 2.

In FIG. 3 the end frames 12 are connected by a pair of stretchers 40 at floor level and by a central bridge made of a pair of side by side trusses in order to resist the deflection of the embossing operation. End frame extensions 42 stand above the bridge for a purpose to be described.

Flanges 44 extend from the end frames in order to seat 15 pairs of hd bearings 46. The bearings support two anvil rolls 48, 500mm in diameter and 2800mm long. An infeed table 2, 1800mm long rests on rail 50 located between the rolls and a leg frame 52. The table has a slot 54 for each roll. The slots are the embossing sites.

C Thirteen embossing wheels 18 create nips with each roll. Twenty six embossing grooves are therefore possible across the larger dimension of the panel. The 2 two sets of wheels 18 are staggered to permit a small tile effect. The wheels are 300mm dia.and each is supported in a 300mm long bifurcated holder 56 which is fixed to the truss. Each holder 56 has a bore in which the wheel holder 58 is a slide fit.

The wheel and holder is urged downwardly toward the anvil roll by a pneumatic ram 20 fixed to the end frame extensions 42. As the size of the nip determines the J r~ depth of the groove, the ram has a threaded rod protruding from the upper end of the ram. the rod has a nut adjustment 62 which acts as a stop on the downward travel of the ram. The anvil rolls are chain driven by a motor and reduction gearbox 64 with chain tensioners 66 at 12m/min.

A run of panels is passed through the machine and stacked. The panels are then passed through the machine in the reverse direction but at 90 degrees.

Accuracy is vital as the sheets must match exactly in installation. We have found the advantages of the two embodiments to be 1. imitation tile effects are possible.

2. panels with a range of hardness can be embossed on 15 the same machine.

3. the embossed panels do not split in handling as a result of the embossing operation.

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Claims (27)

1. A method of embossing a substrate of the type as herein defined using an embossing means having a series of stationary side by side tools mounted adjacent a stationary work surface being capable of embossing to a constant depth across a surface of the substrate including contacting the substrate surface with an embossing tool with a pressure which is great enough to emboss but insufficient to render the panel susceptible to splitting.

2. A method of embossing a panel as claimed in claim 1 wherein the embossments are indented as mutually parallel tracts.

3. A method as claimed in claim 1 or 2 wherein the embossing pressure is applied by a fluid operated device whereby equal pressure is utilised despite fluctuations in panel thickness.

4. A method as claimed in any one of claims 1 to 3 wherein the panel thickness is 5-10mm and the S. embossments are 0.5-1.8mm deep.

5. A method as claimed in any one of claims 1-4 wherein a panel is embossed along a first axis in a first pass and a panel return stage returns the panel automatically for a second pass.

6. A method as claimed in any one of the preceding claims wherein there is an embossing station to which a workpiece is admitted and removed and movement means capable of providing relative movement between the embossing means and the workpiece. TO< -I II--

7. Apparatus for performing the method as claimed in any one of the preceding claims having an embossing station to which a workpiece is admitted and removed; an embossing means having a series of stationary side by side tools mounted adjacent a stationary work surface being capable of embossing to a constant depth across a surface of the substrate; and a movement means capable of providing relative movement between the embossing means and the workpiece.

8. Apparatus as claimed in claim 7 wherein the tools are held in a stiff mount extending from a rigid bridge in order to control the flexing of the station during embossing when the sum of the forces of each tool is resisted by the bridge.

9. Apparatus as claimed in claim 8 each tool imparts the embossing pressure by a ram and the rams are oe actuated by a common fluid pressure. oo Apparatus as claimed in any one of claims 7-9 wherein the embossing tools are wheels. e

11. Apparatus as claimed in claim 10 wherein the embossing wheel is of bevelled, arcuate or V-shaped section. o 12. Apparatus as claimed in any one of the preceding claims wherein the work surface is wide enough to treat a rectangular panel in two axes at 90 degrees.

13. Panel embossing apparatus substantially as herein described with reerence to and as illustrated in Fig. 1 and 2.

14. A panel embossing method substantially as herein dLI-E-- Ip l I~ described. Panel embossing apparatus including an embossing station, embossing means, and movement means as claimed in Claim 10 wherein there is an anvil roll disposed transversely to the direction of panel feed, the series of embossing wheels providing a series of nips along an anvil roll circumference and a guideway located tangentially to the nip and parallel to the feed direction.

16. Panel embossing apparatus as claimed in claim having a pair of adjacent, mutually parallel anvil rolls, a series of embossment wheels providing nips with each roll, the two series of embossing wheels being staggered to permit closer spacing.

17. Panel embossing apparatus as claimed in claim 16 or 17 wherein the guideway is a table with a slot for ethe or each nip. V. ~18. Panel embossing apparatus as claimed in any one of o claims 15-17 wherein at least one of the anvil rolls is driven to provide feed motion for the nip.

19. Panel embossing apparatus as claimed in any one of S.claims 15-18 wherein the anvil rolls are 500-600mm in diameter. Panel embossing apparatus as claimed in any one of claims 15-19 wherein embossing wheels are 250-300mmm in diameter.

21. Panel embossing apparatus as claimed in any one of claims 15-20 wherein the anvil roll is mounted in a bed and the or each emnbossing roll is mounted in a bridge L l 11 which permits panels of substrate to pass through an elongate aperture in which the nips are located.

22. Panel embossing apparatus as claimed in any one of claims 15-21 wherein the or each embossing wheel is mounted in a wheel holder which permits rise and fall of the wheel.

23. Panel embossing apparatus as claimed in any one of r.laims wh :rein the holder has a slide with an upper end and a lower end, the lower end carrying the embossing wheel.

24. Panel embossing apparatus as claimed in claim 22 or 23 wherein the upper end of the slide is urged by a S• ram. Panel embossing apparatus as claimed in any one of 15 claims 22-24 wherein each holder and the wheel form an embossing assembly and the assembly has an adjuster which permits fine adjustment of the embossing depth.

26. Panel embossing apparatus as claimed in claim o wherein the ram has a screw operated stroke adjustment. 20 27. Panel embossing apparatus as claimed in any one of claims 15-26 wherein the anvil roll feed speed is 8-

28. Panel embossing apparatus as claimed in any one of claims 15-27 wherein the embossing pressure is lOOpsi

29. Embossing apparatus including: a stationary work surface or an anvil roll for supporting a workpiece to be embossed at an embossing station comprising ft3 W^ I^0 'I one or more embossing tools operable by variable pressure tool operating means. Embossing apparatus as claimed in Claim 29 wherein the tools comprise a series of side by side tools.

31. Embossing apparatus as claimed in any one of Claims 29 or 30 wherein said tool operating means comprises a hydraulic ram.

32. Embossing apparatus as claimed in Claim 31 wherein the rams are actuated by a common fluid pressure.

33. Embossing apparatus as claimed in any one of Claims 29 to 32 wherein the pressure of said variable Z6 pressure tool operating means the embossing tools are capable of embossing a selection of workpieces to a constant depth.

34. Embossing apparatus as claimed in any one of the Claims 29 to 33 wherein the tool is a wheel having a bevelled, arcuate, or V-shaped section.

35. Panel embossing apparatus substantially as herein described with reference to and as illustrated in Fig. 20 3 of the accompanying drawings. DATED THIS THIRTY-FIRST DAY OF JULY 1997. A J BATES LIMITED BY PIZZEYS ABSTRACT Building panels are embossed to imitate tiles. The machine has a pair of parallel, driven anvil rolls A series of embossing wheels (18) form a series of nips with each anvil roll and an infeed\outfeed table is arranged around the nips so that the panel can be fed through the nips forming parallel embossment grooves. The machine is wide enough to return the panel when rotated through degrees. Rams (20) maintain embossing pressure. Depth adjusters (62) control the ram stroke. 8 A simpler version has reciprocating panel feed *too C 00 *CO O* oo*S