GB2118072A - Applying granules to tiles - Google Patents

Abstract

Roofing tiles are partially granulated by passage in succession beneath a chute (7) which discharges granules onto a triangular deflector (8). The deflector (8) is pivotable about a horizontal axis between two positions so as to deflect granules in two directions. The position of the deflector (8) is controlled as a function of tile position. The deflector operates in one position to provide the leading edge (14) of a tile with granules (Figs. 3 and 4) and then in the other position to provide the top surface (15) with granules (Figs. 5 and 6). Granulation of the surface (15) continues up to cut-off point (16) to leave the remainder ungranulated, the deflector then pivoting (Fig. 7) back to its initial position. <IMAGE>

Description

SPECIFICATION Method and apparatus for manufacturing building tiles with partially granulated surfaces This invention relates to building tiles, such as concrete roof tiles, with granulated surfaces, wherein a predetermined portion of an otherwise totally granulated tile surface is not granulated during manufacture of the tile. The invention is particularly related to a method and an apparatus for manufacturing a building tile having a partially granulated surface.

An advantage associated with tiles having surface area portions which are not granulated is that, in use of the tiles in adverse weather conditions, such as, in heavy rain and strong winds, the non-granulated and generally smooth portions of the imbricated tiles substantially reduce or even prevent the possibility of the ingress of water between the tiles. Additionally, this type of tile can be used to construct roofs whose pitches are lower than those of roofs constructed from tiles with totally granulated surfaces, in view of the lack of or substantial reduction in the ingress of water between the imbricated tiles which are manufactured in accordance with the invention.

Another advantage associated with this type of tile is that the juncture between the granulated and non-granulated portions of the tile surface provides a reference line which facilitates a tiler's task in aligning the tiles with respect to each other to provide the proper imbrications necessary for a regular tile array.

A known method and apparatus for partially granulating a tile surface employs a mask of sheet metal which is located over the portion of the tile surface which is not to be granulated. However, this arrangement has inherent disadvantages, in that, firstly, excess granules tend to be deposited on the supposedly ungranulated tile portion due to the accumulation of granules on the sheet metal mask and, secondly, the comparatively high speed of the tiles and the high operating movement of the mask during the granulating process tends to cause excess granules to fall on to the tile surface portion which is to be maintained in an ungranulated condition.

Another method and apparatus for partially granulating tile surfaces uses a bucket-shaped mask whose lower surface engages the tile surface portion requiring no granulation and which collects excess granules which would otherwise fall on this surface portion. The collected excess granules are then recirculated to a granule supply for subsequent use in the partial granulating operation, as each bucket mask is inverted over the granule supply. Although this second arrangement is better than the first known arrangement described above, it also has a certain disadvantage, due to the comparatively high speed at which the bucket-shaped masks are operated, in that they tend to spill some of the excess granules on to the moving tiles on inversion over the granule supply during the recirculation step.That is to say, not all the excess granules are returned directly to the supply but some spill over on to the tiles passing beneath.

Additionally, and also owing to the speed of the bucket-shaped masks, they tend to vibrate substantially causing some of the excess granules received therein to be dislodged and, as a consequence, to fall on the tiles below.

Furthermore, the masks have to be synchronised with the movement of the tiles at the granulating station and this synchronisation tends to be difficult and costly to achieve satisfactorily.

Accordingly, the present invention sets out to provide a method and apparatus for partially granulating a tile surface, which eliminate, or at least substantially eliminate, the disadvantages associated with the known method and apparatus, as described above.

In accordance, therefore, with one aspect of the invention, there is provided a method of granulating predetermined portions of consecutive tiles moving through a granulating station, which method comprises the steps of: (a) deflecting a stream of granules in a first direction on to a first part of a predetermined portion of the surface of a moving tile to be granulated; (b) deflecting the stream of granules in a second direction on to a second part of the tile surface portion to be granulated, to provide a continuous granulated layer over the tile surface portion constituted by said two parts thereof;; (c) again deflecting the stream of granules in the first direction on to a first part of a predetermined portion of the surface of the following moving tile, to provide a predetermined non-granulated surface portion of the firstmentioned tile, with a substantially distinct cut-off between the granulated and non-granulated portions thereof; and (d) repeating steps (a) to (c) with respect to the following and subsequently following tiles.

In accordance with another aspect of the invention there is provided an apparatus for granulating predetermined portions of consecutive tiles moving through a granulating station, which apparatus comprises: (a) means arranged to deflect a stream of granules from a granule supply in a first direction on to a first part of a predetermined portion of the surface of a moving tile to be granulated; and (b) means arranged to actuate said deflecting means to deflect the stream of granules in a second direction on to a second part of the tile surface portion to be granulated, whereby a continuous granulated layer over the predetermined tile surface portion, and then to actuate said deflecting means to deflect the stream of granules in the first direction on to a first part of a predetermined portion of the surface of the following moving tile, whereby a predetermined non-granulated surface portion of the first-mentioned tile is provided, with a substantially distinct cut-off between the granulated and non-granulated portions thereof.

Preferably, said means for deflecting the stream of granules comprises a triangularly shaped deflector having two longer sides which cause the granules to be deflected in the respective directions. In such a case, the angles of the two loner sides of the triangular deflector, the angle of incidence of the stream of granules with respect thereto and the speed of the moving tiles to be granulated are computed to provide the necessary granulation of the two parts of the tile surface portion. This triangular deflector is preferably located below a granule supply such that the granule stream is fed to the deflector, and subsequently on to the tile surface, under gravity.

However, any other suitable form of arrangement may be provided for causing the necessary deflections off the deflector.

Advantageously, the triangular deflector is mounted above the moving tiles and is pivotable about a preferably horizontal axis between two positions for causing the respective deflection of the granule stream in the two directions with respect to the tile to be granulated.

The triangular deflector can be pivoted between these two deflecting positions in dependence upon a signal from a sensor, such as, a proximity detector, which determines the instant at which the deflection direction of the granule stream is to be changed by sensing the juncture between the predetermined granulated portion of a tile and the tile portion which does not require granulation.

In one particularly desirable embodiment of the invention, the apparatus is totally enclosed within a housing, thus preventing the undesirable spread of the granules and retaining them within a confined space.

In order that the invention may be more fully understood, a preferred embodiment, in accordance therewith, will now be described by way of example and with reference to the accompanying drawings in which: Fig. 1 is an end elevational view of the apparatus; Fig. 2 is a side elevational view of the apparatus shown in Fig. 1; and Figs. 3 to 7 are side views of the steps involved in the method employed by the apparatus of Figs.

1 and 2 for partially granulating building tiles.

Referring to Figs. 1 and 2 of the drawings, an apparatus for granulating predetermined surface portions of tiles 1 comprises a sealed housing 2 into which the tiles to be partially granulated are fed upon a conveyor 3 in the direction of the arrow A. The conveyor 3 consists of a pair of endless polycord belts driven by conveyor pulleys 4 and supported on intermediate pulleys 4'.

A supply of granules to be supplied on to a predetermined surface area of the tiles 1 includes a table 5 which is vibrated by means of a vibrator 6 to provide a continuous stream of the granules down a supply chute 7. Below the chute 7 is a triangularly-shaped deflector 8 located above the tiles 1 moving along the conveyor 3 through the housing 2 at the granulating station 10.

The triangular deflector 8 is pivotable about a generally horizontal axis between two positions to deflect the stream of granules from the chute 7 in two respective directions, as will be described in detail hereinbelow.

Associated with the granulating station 10 is a proximity detector (not shown) which is arranged to detect when the granulation of the predetermined surface portion of a tile 1 has been completed. On such detection, the detection provides a signal for operating a pneumatic piston 11 which, in turn, causes the triangular deflector 8 to be pivoted from one position to another position to commence partial granulation of the following tile.

Similarly, the detector also provides a signal to cause the deflector 8 to be moved back to the one position thereof at a certain position of the tile 1.

Referring now to Figs. 3 to 7, Fig. 3 shows the triangular deflector 8 in a first position in which the stream 1 3 of granules is delfected, as it leaves the chute 7, along the left hand, longer side of the deflector and on to the leading edge surface 14 of the tile 1' following a downstream tile 1 which has already been partially granulated. When the tile 1' has been moved a certain distance by the conveyor 3 in the direction of the arrow 3, the proximity detector (not shown) determines that the leading edge surface 14 of the tile 1' has been granulated as shown in Fig. 4, and actuates the pneumatic cylinder 11 to pivot the detector 8 into a second position, as shown in Fig. 5, such that the granule stream 13 is now deflected along the longer, left hand side thereof and on to the upper surface 1 5 of the tile 1.On further movement of the tile 1 ' along the conveyor 3, as shown in Fig.

6, the predetermined surface portion of the tile 1' is granulated up to the juncture or cut-off 1 6 at which time the proximity detector then senses the position of the tile 1 ' and actuates the pneumatic cylinder 11, as shown in Fig. 2, which consequently pivots the triangular deflector 8 back to its first position for commencing partial granulation of the following tile 1", as shown in Fig. 7. The partial granulation process is then repeated on the next tile.

It will be appreciated that any suitable arrangement may be provided for the combination of the sensing means (proximity detector 11), the pneumatic operating cylinder 11 and the pivotal actuation of the triangular deflector 8. In essence, the sensing means detects the change in level between the granulated and non-granulated surface portions of each tile as it passes through the granulating station. However, the sensing means may be arranged to pivot the deflector 8 from one position only to the other position, in which case, the return of the deflector to the one position can be effected under a spring bias, or other suitable means, when the sensing means is de-activated at the juncture of the granulated and non-granulated tile surface portions or when the leading edge surface of each tile has been granulated. Alternatively, operation of the sensing means and consequential pivoting of the deflector may be in synchronism with the position of the tile with respect to the sensing means.

The apparatus and method in accordance with the invention provides the following advantages: 1. The non-granulated tile surface portion is completely free of any excess or stray granules; 2. The juncture between the granulated and non-granulated portions of the tile surface is a clean cut-off line; 3. Greater thickness of granulation yielding higher quality product; 4. The apparatus requires little maintenance; 5. Very little mechanical wear of the apparatus; 6. The cut-off line is adjustable for varying predetermined granulated tile surface portions; 7. The apparatus is completely and automatically synchronised.

8. Little or no waste of granules; 9. Dust is reduced to a minimum due to the sealing apparatus housing; 10. The granules are fed through the central part of the apparatus; 11. The apparatus can be incorporated in any tile conveying equipment; 12. Wastage is substantially zero; 13. The apparatus is easily and economically fabricated; and 14. Low running costs are involved.

Claims (14)

1. A method of granulating predetermined portions of consecutive tiles moving through a granulating station, which method comprises the steps of: (a) deflecting a stream of granules in a first direction on to a first part of a predetermined portion of the surface of a moving tile to be granulated; (b) deflecting the stream of granules in a second direction on to a second part of the tile surface portion to be granulated, to provide a continuous granulated layer over the tile surface portion constituted by said two parts thereof; (c) again deflecting the stream of granules in the first direction on to a first part of a predetermined portion of the surface of the following moving tile, to provide a predetermined non-granulated surface portion of the firstmentioned tile, with a substantially distinct cut-off between the granulated and non-granulated portions thereof; and (d) repeating steps (a) to (c) with respect to the following and subsequently following tiles.

2. A method according to claim 1, wherein the granule stream is deflected in the two directions by means of a triangularly-shaped deflector pivotable between two positions corresponding to the respective directions.

3. A method according to claim 2, wherein the triangular deflector is pivoted between its two positions in dependence upon a signal from a sensing means for determining the instant at which the deflector is to be pivoted as a result of the position of the tile with respect thereto.

4. A method according to any preceding claim, wherein the granule stream is fed under gravity from a granule supply to the deflector, the moving tiles being located beneath the deflector.

5. A method of partially granulating a building tile substantially as hereinbefore described with reference to the accompanying drawings.

6. An apparatus for granulating predetermined portions of consecutive tiles moving through a granulating station, which apparatus comprises: (a) means arranged to deflect a stream of granules from a granule supply in a first direction on to a first part of a predetermined portion of the surface of a moving tile to be granulated; and (b) means arranged to actuate said deflecting means to deflect the stream of granules in a second direction on to a second part of the tile surface portion to be granulated, whereby a continuous granulated layer over the predetermined tile surface portion, and then to actuate said deflecting means to deflect the stream of granules in the first direction on to a first part of a predetermined portion of the surface of the following moving tile; whereby a predetermined non-granulated surface portion of the first-mentioned tile is provided, with a substantially distinct cut-off between the granulated and non-granulated portions thereof.

7. An apparatus according to claim 6, wherein said means for deflecting the stream of granules comprises a triangularly-shaped deflector having two sides arranged to cause the granules to be deflected in the respective directions.

8. An apparatus according to claim 7, wherein the angles between the two sides of the triangular deflector, the angle of incidence of the granule stream with respect thereto and the speed of the moving tiles are computable to provide the required granulation of the two parts of the predetermined tile surface portion to be granulated.

9. An apparatus according to claim 6, 7 or 8, wherein the deflector means is located below a granule supply such that the granule stream is fed therefrom under gravity and then on to the tiles below and after deflection.

10. An apparatus according to claim 7, 8 or 9, wherein the triangular deflector is pivotable about a generally horizontal axis.

1 An apparatus according to claims 6 to 10, wherein the deflecting means is movable between the deflecting positions in dependence upon a signal from securing means for determining the instant at which the deflective direction of the granule stream is to be changed.

12. An apparatus according to claim 11, wherein said sensing means is arranged to sense the juncture between the granulated and nongranulated portions of each tile surface.

13. An apparatus according to claim 11 or 12, wherein said sensing means is arranged to sense the difference in level between the granulated and ungranulated tile surface portion.

14. An apparatus according to claim 11, wherein said sensing means is arranged to determine the position of each tile with respect thereto, to provide said signal.

1 5. An apparatus according to any of claims 6 to 14, including a housing in which the components of the apparatus are substantially sealed.

1 6. An apparatus according to any of claims 6 to 1 5 including a vibrator for feeding granules via a chute to said deflector.

1 7. An apparatus substantially as hereinbefore described with reference to the accompanying drawings.