GB2341817A

GB2341817A - Punch roller and punch elements

Info

Publication number: GB2341817A
Application number: GB9820553A
Authority: GB
Inventors: William Devereux
Original assignee: BPB Ltd
Current assignee: BPB Ltd
Priority date: 1998-09-21
Filing date: 1998-09-21
Publication date: 2000-03-29
Also published as: GB9820553D0; AU6103199A; WO2000016953A1

Abstract

A punch roller 10 comprises a steel roller core 12 having axles 14 at each end and two steel roller sleeves 16, 16' surrounding the core 12. For ease of mounting on the core 12, the sleeves 16, 16' are split along lines 18, 18'. The sleeves 16, 16' are removably fixed to the core 12 by bolts. The roller sleeves 16, 16' have a plurality of threaded holes in them. These holes are in a random array except that a narrow clear strip 22 each side of the split lines 18, 18' of the sleeves 16, 16' is free of holes. Into the threaded holes are screwed punch elements 24. Punch elements are made from a steel punch 30 rotatably fitted inside a sleeve 26 with the ends of the punch enlarged to prevent any longitudinal movement. The outer surface 34 of the punch has a saw tooth profile 36.

Description

2341817 PUNCH The present invention relates to a punch suitable for

punching tiles of cementitious material such as gypsum.

It is sometimes desired to perforate tiles of cementitious material such as gypsum, particularly for use as ceiling tiles. It is known from GB-A-2 309 985 to perforate gypsum tiles in a press in which an array of punches on a flat punch plate is moved down onto and through the surface of a gypsum tile. If some of the punches are sufficiently long to penetrate through the tile to form through perforations, they co-operate with a perforate die plate below the tile.

The reciprocating vertical movement of the press requires that the tiles are stationary as they are punched; this is inconvenient in a continuous line for the production of perforated tiles. Thus, it has been desired to provide an apparatus for punching tiles such as tiles of a cementitious material such as gypsum which can punch the tiles as they move past the punch apparatus.

According to a first aspect of the Invention there is provided a punch roller comprising a rotatable cylindrical roller and a plurality of punch elements removably located on the roller.

Preferably, the roller comprises: a rotatable cylindrical roller core and a cylindrical roller sleeve removably fixed around the roller core, the plurality of punch elements being removably mounted on the roller sleeve. Preferably, the punch elements screw into holes in the roller sleeve.

Preferably, the cylindrical roller sleeve is bolted to the roller core.

Preferably, the punch elements each comprise a threaded punch sleeve through which extends a punch having a flattened head to prevent it from passing through the punch sleeve in one direction. The punch elements are screwed into the roller sleeve so that the flattened punch heads bear onto the roller core and are in tight engagement therewith; this prevents the punches moving within the punch sleeve The body of the punches is elongate, and preferably has a saw tooth profile on the face which impinges on the tile and longitudinally corrugated sides; the use of such a punch to perforate gypsum tiles is disclosed in United Kingdom patent application no. 98 07775.3.

The invention also provides, in a second aspect, punch elements for the punch rollers of the first aspect.

In this specification, the word 'inner' when used with reference to the punch roller or a part of the punch means toward the centre line of the punch, except where the context requires otherwise; the word 'outer' has the corresponding meaning.

The invention will be further described by way of example with reference to the accompanying drawings in which:

Figure 1 shows schematically a punch roller according to a preferred embodiment of the first aspect of the invention including a punch element according to an embodiment of the second aspect of the invention; Figure 2 shows a partial cross section through the sleeve of the punch roller of figure 1; and Figure 3 shows in cross section a punch element of the punch roller of figure 1.

The punch roller 10 shown in figure 1 comprises a steel roller core 12 and a steel roller sleeve 14 surrounding the core 12. For ease of mounting on the core 12, the sleeve 14 is split along line 16. The sleeve 14 is removably fixed to the core 12 by bolts; exemplary bolts are shown in figure 1 at 18, but it will be appreciated that more bolts may be employed.

The roller sleeve 14 has a plurality of threaded holes 20 (figure 2) in it. These holes are in a random array except that a narrow clear strip 22 (delineated by the imaginary dashed lines in figure 1) each side of the split line 16 of the sleeve 14 is free of holes. Into the holes 20 are screwed punch elements 24 (figures 1 and 3). Each punch element 24 consists of a cylindrical punch sleeve 26 having a threaded outer surface which co-operates with the threaded holes 20 in the roller sleeve 14. The outer end of the punch sleeve 26 terminates in a head 28 having 20 flats for the application of a wrench. Figure 1 shows fewer punch elements 24 on the roller sleeve 14 than will normally be present. An elongate punch 30 extends through the punch sleeve 26. The punch 30 has a flattened head 32 at its inner end and 25 is flared at its outer end 34. The head 32 and flare 34 hold the punch 30 loosely in the punch sleeve 26 so that it does not fall out when the punch element 24 is removed from the roller sleeve 14. The punch 30 is not, however held tightly in the punch sleeve 26, and can rotate freely 30 within it when the punch element is not on the roller sleeve. The cross section of the punches 30 at their outer ends will vary from punch to punch. Preferably, the end faces - 4 of.the punches have a saw tooth profile 36, and the sides of the punches are corrugated. This design of punch has been found to be particularly effective in penetrating gypsum tiles.

A punch element 24 can be made by drilling a central bore through a stainless steel bolt of appropriate size; the head of the bolt provides the head 28 of the punch element. A steel punch 30, without a flattened head 32, is introduced into the bore from the head end, and the 10 inner end of the punch flattened to make the flattened head 32. To prepare the punch roller for use, two roller sleeves 14 are bolted onto a roller core 12, with a gap between them, 15 by means of bolts 18. As many punch elements 22 as are required are screwed into the threaded holes 20 in each roller sleeve 14. It is not necessary that all the holes 20 in the roller sleeve 14 be occupied by punch elements 24; some may be left empty. Preferably a spring washer is 20 interposed between the punch element head 28 and the roller sleeve 14. The punch elements 24 are screwed hard onto the roller core 12 by means of the head 28 of the punch sleeve 26. The flattened heads 32 of the punches 30 bear hard onto the roller core 12 preventing longitudinal 25 or rotational movement of the punches within the punch sleeves 26. The punch roller 10 is mounted, by means not shown, for rotation over a line along which gypsum tiles are moved. A one piece roller may be used instead of the separate 30 roller core and roller sleeve of the preferred embodiment. In this case, the holes 20 are blind holes in the roller surface. Their depth is such that the flattened heads 32 of the punches 30 bear firmly on the bottom walls of the holes when the punch elements 24 are firmly screwed into 35 the holes.

In- use, the punch roller 10 is rotated at a speed and in a direction such that the punches 30 protruding from its surface move with gypsum tiles carried under the punch roller. The gap between the upper surface of the tiles and the punches 30 is set so that the punches penetrate the desired distance into the tile. Punches of different lengths may be employed if desired to provide holes of different depths in the tile. The punch roller of the present invention is suitable for use with all types of gypsum tiles, including gypsum fibreboard tiles.

After punching with the punch roller of the present invention, the tiles can be subjected to further surface treatment. It is particularly preferred that the tiles be passed under a pin roller to supplement the perforations is made by the punch roller with pin holes.

It is preferred that sheets of plasterboard of conventional size are punched by the punch roller of the present invention, rather than individual tiles. Each plasterboard provides eight tiles in a 4 by 2 array; the boards pass under the punch roller so that two tiles are punched at a time. The circumference of the roller sleeve 14 corresponds to the length of one tile; unpunched lands between each tile are left by the clear areas 22 of the roller sleeve surface. Lands between the pairs of adjacent tiles on the board are left by the space between the two sleeves 14 on the roller core 12. The punched plaster board is passed under a pin roller and cut into eight tiles.

The pattern of holes made in the tiles is determined by the location of the holes 20 in the roller sleeve which are occupied by punch elements 24 and the orientation of the punches 30 within the punch elements 24.

The array of holes 20 in the sleeve 14 of the preferred punch roller described is random, to facilitate the provision of a random pattern on the tiles. If a regular pattern is required, the holes 20 may be in a regular array.

The punch roller of the present invention allows the continuous punching of gypsum tiles without the need for the tiles to be stationary during the punching process. It also allows the location and orientation of punches to be varied easily; punches can be removed from and introduced into the roller sleeve readily, and a punch can be rotated in its punch sleeve by loosening the punch sleeve in the roller, rotating the punch and retightening the punch sleeve in the roller. Thus, the pattern given to tiles by the punch rollers of the invention can be readily varied. When the preferred two piece (core and sleeve) roller is used, if the desired pattern cannot be achieved with a particular sleeve, it is a simple matter to replace it with another sleeve having a different disposition of holes in it. If a one piece roller is used, the roller can be replaced.

A further significant advantage of punch rollers of the invention is that a particular pattern of punches can be precisely specified so that identical tiles can be produced on different punch rollers, possibly at different sites. Each punch roller can have an identical roller sleeve, having the same array of holes through it, and the shape, length and orientation within the punch sleeve of the punch used in each hole can be specified.

Claims

1. A punch roller comprising a rotatable cylindrical roller and a plurality of punch elements removably located on the roller.

2. A punch roller according to claim 1 in which the roller has a plurality of holes in it and in which the punch elements are removably located in the holes.

3. A punch roller according to claim 1 or 2 in which the roller comprises:

a rotatable cylindrical roller core; and a cylindrical roller sleeve removably fixed around the roller core, the plurality of punch elements being removably mounted on the roller sleeve.

4. A punch roller according to claims 2 and 3 in which the said holes are in the roller sleeve.

5. A punch roller according to any preceding claim in which a punch element comprises a punch sleeve'and an elongate punch inside the punch sleeve, the punch sleeve being adapted to engage tightly with the roller.

6. A punch roller according to claim 5 in which the punch is rotatable within the punch sleeve, the punch being restrained against rotation when the when the punch element is mounted on the roller.

7.- A punch roller according to claim 5 or 6 in which the inner end of the punch is wider than the bore of the punch sleeve to restrain the punch against significant longitudinal movement in one direction in the punch sleeve.

8.. A punch roller according to claim 5, 6 or 7 in which the outer end of the punch is wider than the bore of the punch sleeve to restrain the punch against significant longitudinal movement in one direction in the punch sleeve.

9. A punch roller according to claim 5, 6, 7 or 8 in which the outer end face of the punch has a saw tooth profile.

10. A punch roller according to any of claims 5 to 9 in which the sides of the outer end region of the punch are corrugated, the corrugations extending longitudinally of the punch.

11. A punch roller according to claim 2 or 4 and to any of claims 5 to 10 in which the outer surface of the punch sleeves and the walls of the holes in the roller are threaded with cooperating threads.

12. A punch roller according to any of claims 3 or 4 and to any of claims 5 to 10 in which the inner ends of the punches bear on the roller core and are thereby restrained against movement.

13. A punch roller according to any preceding claim comprising two rollers mounted side by side on a roller core.

14. A punch roller according to any preceding claim in which an axial strip of the roller surface is free of punch elements.

15. A punch roller according to any preceding claim for perforating tiles such as cementitious tiles in which the outer circumference of the roller corresponds to the length or width of a tile.

16- A punch roller according to claims 14 and 15 in which the said axial strip corresponds to unpunched lands at the leading and trailing edge of the tiles.

17. A punch element for a punch roller according to any preceding claim comprising a punch sleeve and an elongate punch inside the punch sleeve.

18. A punch element according to claim 17 in which the punch is rotatable within the punch sleeve.

19. A punch element according to claim 17 or 18 in which the inner end of the punch is wider than the bore of the punch sleeve to restrain the punch against significant longitudinal movement in one direction in the punch sleeve.

20. A punch element according to claim 17, 18 or 19 in which the outer end of the punch is wider than the bore of the punch sleeve to restrain the punch against significant longitudinal movement in one direction in the punch sleeve.

21. A punch element according to claim 17, 18, 19 or 20 in which the outer end face of the punch has a saw tooth profile.

22. A punch element according to any of claims 17 to 21 in which the sides of the outer end region of the punch are corrugated, the corrugations extending longitudinally of the punch.

23. A punch element according to any of claims 17 to 22 in which the outer surface of the punch sleeve is threaded.