GB2240067A

GB2240067A - Apparatus for removing a surface layer from a piece of material

Info

Publication number: GB2240067A
Application number: GB8927424A
Authority: GB
Inventors: Bernard Sutcliffe
Original assignee: SHAW TIMBER Ltd
Current assignee: SHAW TIMBER Ltd
Priority date: 1989-12-05
Filing date: 1989-12-05
Publication date: 1991-07-24
Also published as: GB8927424D0

Abstract

Apparatus for removing melamine facing from chip board comprises a treatment member 10, for example a toothed roller, and feed means 11 for feeding the board past the treatment member in a first, feed direction. The apparatus is such that the treatment member 10, or a part thereof, moves in a second direction, transverse to the feed direction in such a way as to remove the surface layer from the board. The treatment member 10 may have circumferentially extending teeth 13 and an axis of rotation which is inclined to the feed direction, or may have a helical tooth extending therearound. <IMAGE>

Description

APPARATUS AND METHOD FOR REMOVING A SURFACE LAYER The invention relates to apparatus for removing a surface layer from a piece of material. The apparatus has been specifically developed for use in the removal of a surface layer, for example a hard surface coating, from chip board or other reconstituted timber. However, the apparatus is not restricted to this use, and is of general application.

A typical example of this type of material would be melamine faced chip board. This is ordinary board, the type you might find in flooring in new houses, which has had a layer of paper bonded to either one, or both, faces of the chip board. (Typical use for MFC would be in the manufacture of kitchen units and the like).

This is done as a secondary process at the point of manufacture using heat and adhesive. The resulting bond is extremely strong and very difficult to disturb.

However, during the manufacturing process itself, large volumes of reject MFC (melamine faced chip board) are produced, this can be due to defects in the board, defects in the paper or inaccuracies during application.

In this form the reject MFC is worth considerably less than the virgin board, but if a means could be found to remove the surface layers, then the material in question could be returned almost to its original condition and its value could be substantially increased.

The obvious way to try to remove the surface layer is by using a surface grinding machine or a planning or milling machine. However we have found that the melamine layer is surprisingly resistant and if a planning or milling machine is used, the blades wear out at an unacceptably high rate. If a grinding machine is used, the grinding wheels rapidly clog up. We have therefore had to develop a special apparatus and method.

Accordingly, the invention provides apparatus for removing a surface layer from a piece of material, comprising a treatment member, and feed means for feeding the material past the treatment member in a first, feed, direction, the apparatus being such that the treatment member, or a part thereof, moves in a second direction, transverse to the feed direction, in a such a way as to remove a surface layer from the piece of material.

The treatment member may have one or more teeth of like projections which move over the surface of the piece of material and scrape or shear away the surface layer.

The treatment member preferably comprises a roller having one or more circumferentially extending teeth.

There may for example be a spiral or helical tooth extending around the roller to provide a plurality of ridges, ribs or like projections, the roller being rotated to bring about relative lateral movement of the projections with respect to the piece of material.

Alternatively, there may be a plurality of annular ridges, ribs or like projections, arranged side by side, the transverse movement being achieved by arranging the axis of rotation of the roller at an inclined angle to the feed direction.

The, or each, projection may have a ramp profile, with a substantially vertical scraping or shearing face, supported by an inclined rear face.

Means may be provided for cleaning the treatment member.

The cleaning means may comprise a comb having teeth arranged to scrape between the projections.

There may be a second, pressure roller, cooperating with the first treatment roller, to press the piece of material against the treatment roller.

There may be an abutment, for example a guide bar, arranged to receive the side load of the piece of material caused by the tendency for the treatment member to move the piece of material in the scraping or shearing direction.

The guide bar may have means to reduce friction as the piece of material moves along the guide bar, for example rollers housed within the guide bar.

To avoid or reduce cumulative side load, a plurality of treatment members may be provided, spaced along the scraping or shearing direction, and arranged to scrape or shear in opposition directions, so that the side loads tend to cancel out.

When it is desired to remove a surface layer from two sides of the piece of material, a second treatment member or second set of treatment members may be arranged downstream or upstream of the first treatment member or set of treatment members.

The invention includes a method for removing a surface layer from a piece of material comprising feeding the piece of material past a treatment member in a first, feed direction, and moving the treatment member or a part thereof, in a second direction transverse to the feed direction, in such a way as to remove a surface layer from the piece of material.

The invention includes material when treated by the apparatus or method of the invention.

The material may comprise chip board for example surfaced with melamine.

By way of example, a specific embodiment of the invention will now be described, with reference to the accompanying drawings, in which : Figure 1 is a perspective view of a treatment member according to this embodiment, in the form of a roller, together with an associated pressure roller; Figure 1A is a diagram showing the tooth formation of the treatment roller of Figure 1; Figure 2 is a plan view showing how a plurality of treatment rollers are used in this embodiment; Figure 3 is a plan view showing the treatment rollers for treating both sides of the material; and Figure 4 is a side view showing one roller pair from each of the sets of rollers shown in Figure 3.

The apparatus according to this embodiment in the invention comprises a plurality of pairs of rollers, one of which will first be described in detail, with reference to Figures 1 and 1A. The pair shown in Figure 1 comprises a treatment roller 10 and a pressure roller 11. Each roller is shown mounted in bearings comprising plain bronze bushes 12 but the use of taper roller bearings is preferred.

The pressure roller 11 has a plain surface, but the treatment roller 10 has a large number of annular projecting teeth 13. The exact form of these teeth can be seen in Figure 1A. Each tooth has a vertical scraping or shearing face 14, supported by a ramp like rear face 15.

There now follows, with reference to Figure 2, a description of how a plurality of roller pairs of the form shown in Figure 1, are used to remove a surface layer from a section of melamine faced chip board.

A section of chip board is pushed into contact with a first pair of rollers 16 with one side edge of the board in contact with a guide bar 17. Rotation of the rollers 16, by means of a motor (not shown) drives the chip board in the direction of arrows A. Because the coefficient of friction between the pressure roller and the chip board is low, it is preferred that the treatment rollers are driven, but the pressure rollers may be driven as well.

Because the rollers 16 are arranged at an angle of about 150 to the transverse direction, the teeth 13 move, with respect to the board, towards the guide bar 17, during the cutting part of their rotation. This produces a transverse scraping or shearing action which has been found to remove very effectively and neatly the surface layer of the faced chip board.

It would be possible to use a single pair of rollers extending across the full width of the chip board, but this would produce a very substantial side load, which could crush or damage the chip board where it comes into contact with the guide bar 17. It is therefore preferred to use a set of rollers, as shown in Figure 2, with the rollers inclined in different directions, so that they scrape or shear in opposite directions. As viewed in Figure 2, there are shown five pairs of rollers which are inclined to the left, alternating with four pairs of rollers which are inclined to the right. Thus, most of the side loads cancel out, leaving only a slight resultant load to keep the chip board in contact with the guide bar 17.

Of course, any desired number of rollers may be used, dependent upon the width of the chip board.

The apparatus of this embodiment is intended to treat both faces of the chip board, but it is preferred not to use two opposed treatment rollers, because it is then difficult to ensure that the rollers cut into the board by equal amounts. If two opposed treatment rollers are used, there is a tendency for one treatment roller to cut into the board more than the other treatment roller with the result that the surfaces of the board are unevenly treated, and they can be left with grooves or other marks.

In this embodiment, two sets of rollers such as those shown in Figure 2 are used, and Figure 3 shows the positioning of the two sets. Figure 3 also shows the guide bar 17 in more detail, and it will be seen that the guide bar 17 has, housed therein, two rollers 18 and 19 to reduce friction between the chip board and the guide bar 17.

The precise way in which one roller pair of each set operates on the chip board is shown in the side view of Figure 4.

In the first pair 20, the pressure roller 11 is on the top and the cutting roller 10 is underneath. Thus a lower surface layer of the chip board 22 is removed, and the thickness of the layer can be precisely controlled by adjusting the distance between the rollers 10 and 11.

Downstream of the pair 20 the second pair 21 is arranged to remove an upper surface layer, by positioning of the cutting roller 10 on the top, and the pressure roller 11 on the bottom.

In order to prevent the spaces between the teeth 13 from becoming clogged up, a scraping comb (not shown) is arranged alongside each cutting roller 10 with the teeth of the comb projecting into the spaces between the teeth 13. Each scraping comb is stationary so that as the roller 10 rotates with respect to the comb, the spaces between the teeth 13 are scraped clear.

Alternative arrangements are possible. For example the cutting rollers can be provided with a single spiral or helical tooth, or with a plurality of such teeth, for example in the manner of a worm gear wheel.

This would enable the axes of the rollers to be arranged at right angles to the feed direction, but would make cleaning of the teeth more difficult.

Since it is difficult and expensive to provide a synchronised drive to all the cutting and feed rollers, separate feed rollers may be provided which may, for example, be arranged at right angles to the guide bar and extend across the full width of the chip board.

A pair of feed rollers may be arranged upstream of the treatment rollers.

Alternatively, or in addition, a pair of feed rollers may be arranged downstream of the treatment rollers.

One, or both, feed rollers of the, or each, pair may be driven.

The feed rollers may comprise metal rollers, coated rollers (e.g. coated in rubber), knurled rollers, or a combination thereof.

For example knurled or similarly roughened rollers may be provided upstream of the treatment rollers to pre-treat or break up the melamine layer prior to contract with the treatment rollers.

Smooth finishing rollers may be provided downstream of the treatment rollers to assist in providing the treatment chip board with a smooth finish.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. Apparatus for removing a surface layer from a piece of material, comprising a treatment member, and feed means for feeding the material past the treatment member in a first, feed, direction, the apparatus being such that the treatment member, or a part thereof, moves in a second direction, transverse to the feed direction, in such a way as to remove a surface layer from the piece of material.

2. Apparatus as claimed in Claim 1, in which the treatment member has one or more teeth or like projections which move over the surface of the piece of material and scrape or shear away the surface layer.

3. Apparatus as claimed in Claim 2, in which the treatment member comprises a roller having one or more circumferentially extending teeth.

4. Apparatus as claimed in Claim 3, in which there is a spiral or helical tooth extending around the roller to provide a plurality of ridges, ribs or like projections, the roller being rotated to bring about relative lateral movement of the projections with respect to the piece of material.

5. Apparatus as claimed in Claim 3, in which there is a plurality of annular ridges, ribs or like projections, arranged side by side, the transverse movement being achieved by arranging the axis of rotation of the roller at an inclined angle to the feed direction.

6. Apparatus as claimed in any one of Claims 2 to 5 in which the, or each, projection has a ramp profile, with a substantially vertical scraping or shearing face, supported by an inclined rear face.

7. Apparatus as claimed in any one of the preceding Claims, in which means are provided for cleaning the treatment member.

8. Apparatus as claimed in Claim 7, when dependent on any one of Claims 2 to 6, in which the cleaning means comprises a comb having teeth arranged to scrape between the projections.

9. Apparatus as claimed in any one of the preceding Claims in which there is a second, pressure roller, co-operating with the first treatment roller, to press the piece of material against the treatment roller.

10. Apparatus as claimed in any one of the preceding Claims, in which there is an abutment, arranged to receive the side load of the piece of material caused by the tendency for the treatment member to move the piece of material in the scraping or shearing direction.

11. Apparatus as claimed in Claim 10, in which the abutment comprises a guide bar.

12. Apparatus as claimed in Claim 11, in which the guide bar has means to reduce friction as the piece of material moves along the guide bar.

13. Apparatus as claimed in Claim 12, in which rollers are housed within the guide bar.

14. Apparatus as claimed in any one of the preceding Claims, in which, to avoid or reduce cumulative side load, a plurality of treatment members are provided, spaced along the scraping or shearing direction, and arranged to scrape or shear in opposite directions, so that the side loads tend to cancel out.

15. Apparatus as claimed in any one of the preceding Claims in which a second treatment member or second set of treatment members is arranged downstream or upstream of the first treatment member or set of treatment members.

16. Apparatus constructed and arranged substantially as herein described, with reference to the accompanying drawings.

17. A method for removing a surface layer from a piece of material comprising feeding the piece of material past a treatment member in a first, feed direction, and moving the treatment member or a part thereof, in a second direction transverse to the feed direction, in such a way as to remove a surface layer from the piece of material.

18. A method for removing a surface layer, substantially as described herein, with reference to the accompanying drawings.

19. Material when treated by the apparatus described in any one of Claims 1 to 16 or the method claimed in Claim 17 or Claim 18.