AU2005239721A1 - A horizontal extrusion method - Google Patents

Description

C05171 t A HORIZONTAL EXTRUSION METHOD

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Technical field [01] This invention relates to double sided tiles, and methods and apparatus for their manufacture. The invention also relates to a method and system for synchronising a cutting mechanism for cutting tile extrudates on the fly.

Cc Background art

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[02] In known products, tiles are formed either with no pattern or with a pattern on only one face. Where patterned tiles are required, then, unless an identical pattern is used for all the tiles, different tiles are required where fancy or varying tiles are required. When ordering tiles for a job, it is usual to over order to allow for breakage. When fancy patterns requiring tiles with two or more patterns are to be installed (coordinated patterns), surplus tiles of each pattern are required. Thus, a double sided tile can reduce the overall number of tiles required for a job by reducing the number of spare tiles required. Further, a double sided tile can reduce the number of inventory items a shop needs to carry.

[03] In known fabrication processes, tiles are formed by horizontal casting or extrusion.

Patterns can be impressed on the top surface of the tiles during drawing, but not on the lower side because the pattern would be damaged. Current horizontal extrusion processes are not suitable for forming double sided tiles because the pattern on the underside may be damaged during subsequent handling and processing.

Disclosure of the invention [04] This invention proposes a tile having a pattern on both faces.

The invention also proposes a method of manufacturing double sided tiles.

[06] The invention further proposes a manufacturing plant for producing double sided tiles..

C05171 2 o [07] According to a first embodiment of the invention there is provided a tile including a pair of opposed faces, wherein a pattern is formed on each of the opposed faces.

[08] Preferably the pattern is a relief pattern.

[09] Alternatively the pattern is impressed into the tile.

Cc, [10] The pattern on one face may be a relief pattern and the pattern on the other face In may be impressed into the tile.

[11] The tile can be made by a casting process.

[12] The tile can be made by an extrusion process.

[13] According to a second aspect of the invention there is provided a method of manufacturing tiles from a tile forming material, the tiles having a first and second opposed faces and three or more edges, the method including: preparing the tile forming material in a plastic state such that the material will not slump during piocessing; forming the tile in said plastic state on one of its edges; and imprinting a pattern on each of the major faces.

[14] In a further embodiment of the invention, there is provided the method includes: extruding a continuous column of tile forming material in said plastic state; the column having an extrusion speed and an extrusion direction; impressing a pattern on each of the opposed faces using pattern printing plates; causing the plates to move at the extrusion speed and in the extrusion direction for the duration of the time the plates are in contact with the column.

The plates can be formed on the cylindrical surface of first and second rollers, the first roller being applied to the first face of the column, and the second roller being applied to the second face of the column.

C05171 3 o [16] The line of contact of between the first roller and the column is directly opposite the line of contact between the second roller and the column.

C [17] The force applied to the column by the first plate is substantially equal and substantially opposite to the force applied to the column by the second plate.

[18] A cutting operation can be performed to cut the tiles to a predetermined length Cc using a cutter; while causing the cutter to move at the extrusion speed and in the extrusion tt direction for the duration of the cutting operation.

[19] Cut tiles can be deposited in a substantially upright orientation on one of the edges of the tile onto a support base.

The tiles can be dried while the tiles are in the substantially upright orientation.

[21] The column can be extruded in a substantially upright orientation.

[22] The extrusion speed can be substantially constant.

[23] The cutting operation can be synchronised with the extrusion speed.

[24] The pattern printing operation can be synchronised with the extrusion speed.

In another aspect, an embodiment of the invention provides a tile extruding machine including a die to form a column of tile forming material having a predetermined width dimension and a predetermined thickness dimension; an extrusion driving mechanism to force tile forming material in a plastic state through the die at an extrusion speed; first and second pattern printing plates to print a pattern adapted to fit the width dimension of the column, and print a pattern on respective first and second sides of the column; first drive means to drive the printing plates to move in synchronism with the column during the printing operation.

C05171 4 o [26] The machine can include synchronizing means to synchronise the movement of the S printing plates with the speed of the column.

[27] The first and second plates can be formed on the cylindrical faces of first and second rollers respectively.

[28] The line of contact between the first roller and the column is directly opposite the Cc line of contact between the second roller and the column.

In [29] The force applied to the column by the first plate is substantially equal and substantially opposite to the force applied to the column by the second plate.

A machine can include a cutter adapted to cut the tiles to predetermined lengths in a cutting operation.

[31] The machine can include second drive means to drive the cutting means to move in the direction of and at the speed of the column for the duration of the cutting operation.

[32] The column can be extruded in a substantially upright orientation, the machine including a support base which supports the tiles on an edge as they are cut from the column.

[33] The support base can be part of a conveyor.

[34] The synchronizing means can synchronise the speed of the cutter with the speed of the column during the cutting operation.

According to a further embodiment, the invention provides a method of producing double sided extrudates, the method including the steps of: extruding an extrudate in a plastically deformable condition in an extrusion direction and at an extrusion speed; the extrudate having at least first and second opposed surfaces; C05171 tt performing a pattern pressing operation by passing the extrudate between first and second Sopposed presses so that the first press imprints on the first face and the second press S imprints on the second face; the presses being adapted to exert substantially equal and opposite imprinting pressures in C the respective faces of the extrudate; and imposing a speed to the press pattern so that the pattern or the part of the pattern in contact _with the extrudate travels at the extrusion speed in the extrusion direction for the duration N of the pressing operation.

[36] The presses can be substantially flat plates which travel at the speed of the extrudate for the duration of the pressing operation.

(-i [37] The presses can be cylinders which have a peripheral rotational speed equal to the extrusion speed.

[38] The extrusion can be performed in a vertical direction.

[39] The pressing can be performed in a vertical direction.

The extrusion speed can be detected and the speed of presses can be synchronised with the extrusion speed for the duration of contact.

[41] The invention also provides an extruded material having at least first and second opposed surfaces, wherein the extrudate includes a first pattern applied to the first surface, and a second pattern applied to the second surface.

[42] In a further embodiment of the invention, the tiles can be extruded in a horizontal orientation.

[43] The tiles can be paving tiles.

Brief description of the drawings C05171 6 [44] Figure 1 is a schematic view illustrative of the components of an extrusion machine embodying the invention; Figure 2 is a graph showing the speed profile of the blade, and the profile of a cam N adapted to produce such a speed profile.

[46] Figure 3 illustrates a cam derived from the graphs of Figure 2.

Cc [47] Figure 4 shows an extrusion machine with an alternative means of imprinting the t extrusion.

[48] Figure 5 schematically represents a plan view of an extruder machine embodying the invention and adapted to extrude tiles horizontally on one edge.

[49] Figure 6 shows a second view of the extrusion machine of Figure Figure 7 shows a casting box for producing double sided tiles according to an embodiment of the invention.

[51] Figure 8 is a schematic illustration of a further embodiment of the invention in which the tiles are extruded in a horizontal orientation.

[52] Figure 9 is a plan view of an alternative system for manufacturing double sided tiles using a horizontal extrusion.

[53] Figure 10 is a side view of the system of Figure 9.

[54] Figures 11 &12 show detail of a tile lifting mechanism of the system of Figure 9.

Figure 13 shows an embodiment of an erecting mechanism suitable for use in the system of Figure 9.

C05171 7 [56] Figure 14 illustrates a double sided tile extrusion line in accordance with an embodiment of the invention.

d,) [57] Figure 15 schematically illustrates the loading, pressing and unloading of the tile N press ofFigure 14.

Description of the invention Cc [58] In a first embodiment (Figures 1 to the tiles can be extruded in a substantially t vertical direction, and, in a second embodiment (Figures 5 6) the tiles are extruded in a horizontal direction on edge so that the major face is upright. Figure 1 shows the components of a tile extrusion machine 100 capable of extruding double-sided tiles in accordance with an embodiment of the invention.

[59] A hopper 102 contains the clay, cement, or other material from which the tiles are to be extruded in a plastic state. In a preferred embodiment, the applicants use clay with a moisture content of the order of 18% and a penetrometer reading of the order of 1.6.

However, there is a range of these values which are suitable for use in the invention, and these may readily be determined empirically. A penetrometer range of 1 to 3 may be used.

We have found that, for clay, a penetrometer range of about 1.1 to 2.8 is suitable. A moisture range of about 14% by weight to 20% by weight may be used. We have found that, for clay extrusion, 15% to 19% is suitable. Higher moisture content can be used in casting processes.

A screw extruder 106 draws off continuous flow of extrudate and forces it through a die 108 which forms the extrudate into a continuous extrusion having the required width and thickness of the tiles. The extrusion preferably is drawn off at a constant speed as indicated by the downward arrow Vv.

[61] The extrusion passes between a pair of stamping rollers 110, 112, which may imprint the same or different patterns on either side of the extrusion. The rollers 110, 112 are arranged to have their centres aligned transversely to the extrusion, and each roller applies the same stamping force so that the stamping forces cancel. This substantially C05171 8 Seliminates sideways movement of the extrusion during stamping. The rollers have a

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peripheral speed matched to the extrusion speed V,.

(-i d) [62] A flying cutter 116 is arranged to cut the tiles at the required length. The cutter C needs to be controlled to move at the same speed as the extrusion while the cutter is in contact with the extrusion. Thus for the period when the cutter is in contact with the extrusion, it must move at Vv,. Once the cutting operation is complete, the cutter must be (-i controlled to return to a position from which the next cutting cycle can be performed.

Cc Hence the cutter has a reciprocating vertical speed indicated by the double headed arrow (-i Vr.

[63] The cutter must also move towards the extrudate during the cutting operation and away from the extrudate when the cutting cycle is complete. Thus the cutter must simultaneously move vertically with the extrudate for the duration of the cutting and withdrawal operation, and then must return to a position from which to commence the next cutting operation.

[64] While computer control now makes it possible to operate the cutter so that it is not essential that the cutter returns to exactly the same position each time, in the preferred embodiment, the cutter is controlled to return to the same "starting point". Thus, the cutter can be operated in a cyclic manner as indicated by the dotted circle surrounding the double headed arrow Vr. The essential requirement for the cutter is that it move in the extrusion direction at the same speed as the extrusion while the cutter is in contact with the extrusion.

Again, the extrusion speed may be variable, but the vertical speed of the cutter must be synchronised with the extrusion speed.

In order to reduce the possibility of distortion of the extrudate during the cutting operation, a pair of opposed cutting edges can be used, one on each side of the extrudate.

The cutting edges can be aligned to overlap and slide one over the other during the cutting operation.

C05171 9 V) [66] In an alternative, one cutting edge can be used, and a support bar may be brought Sinto contact with the opposite side of the extrudate during the cutting operation, the support (-i bar moving with the cutting edge in the extrusion direction during the cutting operation.

N1 [67] In a further embodiment, the cutting edge can pass completely through the extrudate and cut from alternate sides of the extrudate, cutting off the predetermined length _at each pass. The cutting edge in this implementation can be double-sided, or can be a "cheese wire" cutter.

(Ni t [68] The cutting edge may be aligned parallel to the surface of the extrudate, so that it effectively makes contact along the cut line. Alternatively, the cutting edge may be angled to the surface so that it only makes contact with a point along the cut line on the surface at any one time during the cutting operation and penetrates through the extrudate at an angle.

In another alternative, the cutting edge may be perpendicular to the major face, so that it cuts only the thickness of the tile. This alternative reduces the overall cutting force applied at any one moment.

[69] While the drawings show the cutting device as knife blades, other cutting devices may be used. For example, a cheese wire type of cutting arrangement may be used. Again, a pair of such wires can also be used.

Where the extrudate is tile clay, the severed tiles are collected on a conveyor 118.

The tiles are transported on one edge to prevent smearing of the patterned faces. The conveyor transports the tiles to subsequent processes such as drying and firing processes.

A robot mechanism is used to handle the tiles without damaging the patterned faces of the tiles.

[71] While the conveyor 118 is shown as moving in the same plane as the horizontal cutting direction of the blades, in one embodiment the conveyor moves at in a different direction from the blades. While this direction can be perpendicular to the cutting direction, other directions are within the scope of the invention. The distance of travel of the cutter in returning to its starting point is sufficient to avoid the individual tiles becoming entangled in the cutting mechanism after the tiles are severed.

C05171 The distance from the cutting blades 116 to the conveyor 118 can be adjusted to equal the length of the tile to within a predetermined tolerance. In the embodiment in which the extrusion is carried out in a vertical direction, a support plate (418 in Figure 4) is I required to support the tile during the cutting operation, and this must move under the end of thee column of tile material during the return of the cutter to the start position and also move with the cutter in the vertical direction during the cutting operation. This support plate may form part of the conveyor system, which can be designed to provide the required vertical movement. ¢€3 In [73] A robot mechanism may lift the tiles by the side edges. In one embodiment the robot mechanism uses a plurality of small spikes to engage the opposite vertical edges of the tiles.

[74] In another embodiment, conveyor 18 includes support plates on which one or more tiles can be deposited and conveyed to a further processing station where the tiles are removed from the support plates.

Figure 2 illustrates in the lower graph 202 the reciprocal speed, Yr, of the cutting device. In the case where the knives return to the same starting point, the speed profile must be such that the area of the curve above the zero reference should equal the area of the curve below the zero reference. In other words, the net time integral of the speed profile of the flying cutter for one cycle is zero.

[76] As Figure 2 shows, the knives first accelerate up to the extrudate speed, Vv at tI.

Once the knives have reached the extrudate speed, they maintain a constant velocity as shown at 204 for a period which is at least as long as the cutting operation, for the time taken for the blades to pass through and be withdrawn from the extrudate. Preferably the blades maintain the extrudate speed for a slightly longer period, commencing shortly before the cutting operation to ensure that there is no "overshoot". An additional "guard period" may also be provided after the cutting operation is complete. The cutting period is, for example, from t 3 to t 4 C05171 11 [77] The transition from the acceleration part of the curve to the constant speed part of Sthe curve 204 should be smooth to reduce shock and vibration. Preferably the tangent to the curve at the point where the blades attain the extrudate speed should be horizontal.

Similar considerations applyto deceleration. The lower part of the cycle may be pure sinusoidal to reduce the discontinuous acceleration effects of acceleration and deceleration.

[78] Where the pattern imprinted on the extrudate is random, the blades do not need to betightly synchronised with the pattern presses. However, where the pattern is regular or Cc coordinated, it is important for the cutter to be synchronised with the pattern presses.

[79] The upper graph of Figure 2 represents the profile of a cam 210 adapted to produce the speed profile Vr projected on an angular abscissa. A cam can be provided with a minimum radius hmin, above the centre or rotation. The cam has a constant velocity section which corresponds to a constant height/angle section 212. The remainder of the cam surface should provide a smooth transition to between the constant velocity region 212 and the minimum radius. The rotational speed of the cam is determined by dividing the extrusion speed by the length of the tile. This will result in one cycle of the reciprocal speed of the blades in the extrusion direction. The constant speed portion is synchronised with the cutting operation.

While the cycle of the flying cutter may be continuous as shown in Figure 2, it is also possible to introduce a dwell in the cycle when the cutter has returned to a home position.

[81] Figure 3 illustrates a cam profile 302 formed from the angular projection 210 of Figure 2. The cam is formed by converting the vertical distances of graph 210 to radial lengths in profile 302. The constant velocity portion is indicated at 306 which produces a constant height change per degree of rotation.

[82] A cam follower 304 is also shown, and the cam will impart a speed profile equivalent to curve 202 of Figure 2 to the cam follower 304.

C05171 12 S [83] A second cam, not shown, can be used to produce the required synchronised Shorizontal reciprocation, Vh, of the cutting action.

[84] Figure 4 shows an alternative embodiment in which the pattern roller presses are ,I replaced by flat plates. The same speed profile requirements which apply to the blades of the embodiment of Figure 1 also apply to the pattern plates that is, the plates must be moving in synchronism with the extrudate for the duration of the contact between the plates and the extrudate.

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In Figure 4, a pair of patterned plates 410, 412, are shown as physically connected by a physical "pantograph" mechanism composed of pairs of links 414 which restrains the plates to move in parallel when the apexes of the pairs of links 414 move equally in opposite directions. The same effect may be achieved by other means including hydraulic or electrical drives. As shown by the dotted line around the double headed arrow 416, the plates move in a similar manner to the blades, as shown by the dotted line around the double headed arrow Vr.

[86] Figures 5 6 show orthogonal views of a tile extruding machine according to an alternative embodiment of the invention. In this embodiment, the extrudate is extruded in a horizontal direction with the major face in an upright orientation so that the lower edge of the extrudate can be supported on a conveyor during the cutting operation.

[87] In Figure 5, the feed arrangement is indicated generally at 502, the die is shown at 504, and the extrudate is shown at 524 in side view. The view in Figure 5 shows the tile extrudate side on, so the view of die 504 in Figure 5 relates to the thickness of the extrudate.

[88] The extrusion machine can include a first pair of random patterned rollers 506 which can be applied to the extrudate as it issues from the die 504 to impress a random pattern to both sides of the tile extrudate. The random pattern rollers do not need the tight synchronisation with the extrudate speed which is required for the coordinated pattern rollers, as discussed below. A set of coordinated pattern rollers 508 can also be included.

C05171 13 n The provision of two sets of rollers makes the production of both random pattern and Scoordinated pattern tiles possible with minimum set up.

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[89] A pair of coordinated pattern rollers are shown at 506. Each of these rollers may apply the same or different pattern to the opposed major surfaces of the extrudate. The rollers are driven in synchronism with the speed of the extrusion by motors such as 522.

_As shown in Figure 6, the rollers are driven via speed-control gear motors 612.

(-i Cc [90] While the extrusion speed may be nominally constant, the system is adapted to take t account of variations in extrusion speed.

[91] A speed sensing mechanism is provided to sense the speed of the extrudate as it passes through the rollers 508. In this embodiment, a free-wheeling conveyor 510 is driven by the extrudate 524. The conveyor 510 has a plurality of rollers 512, to one of which a speed sensor 520 is connected. This may be, for example, a Grey coded disc which is read optically to provide an indication of the speed of rotation of the disc and hence of the speed of the column of extrudate. The output of the speed sensor is used to synchronise the speed of the drive motors 522 driving the coordinated pattern rollers 508.

[92] The patterned extrudate column 524 then passes the flying cutter 514 shown in an initial position in solid lines, and in a second position in dotted lines.

[93] As discussed with reference to Figure 1, the cutter is locked in synchronism with the patterned rollers. To this end, the drive mechanism for the flying cutter 514 is also controlled by the speed sensor.

[94] As shown in Figure 6, a position sensor 610 can be used to detect when the flying cutter 514 is at a "home" position.

The flying cutter 514 can be driven in the extrusion direction by a first motor and in the cutting direction by a second motor In one embodiment, the flying cutter 514 is controlled by the position of the patterned roller. The sensor 520 can be locked in relation to the rotational position of patterned rollers 508. Thus a cutting operation cycle of flying C05171 14 t cutter 514 can be synchronised with respect to the patterned rollers 508. This can be achieved by correlating the position sensing signal from sensor 610 with a position signal from sensor 520.

,I [96] In an alternative embodiment, tiles are cast in a mould which is box shaped, having a pair of major opposed faces and three or more sides. Figure 7 shows a casting box 700 having major faces 702 and 704, and side walls 706 and 708. The faces 702 and 704 carry S the pattern to be imprinted on the tiles.

(Ni I [97] The box is adapted to be disassembled or the sides 702, 704, 706, 708 are hinged to permit the box to be opened sufficiently to release the tile after casting without damage to the pattern.

[98] The box has an open top with provision for a top piece 710 to be attached or inserted. In the example shown, slots 712 are provided in faces 702 and 704 to permit top piece 710 to be slid into place. The top piece can be used to shave off the excess clay to produce a square finish. Alternatively, the top may be closed and the clay injected into the box.

[99] The box has an open bottom and top. A base member 714 is provided which has a rectangular slot 720 matching the periphery of the bottom of box 700. Thus, the bottoms of the sides 702, 704, 706, and 708 can be inserted into the slot 720.

[100] Where the walls of box 700 are not connected, additional latching means may be provided to hold the walls together. The walls of box 700 may be held by latches provided at each edge.

[101] Alternatively, in another embodiment, the box may be capped with a cap similar to the base unit 714 instead of the top piece 710.

[102] The base member 714 may also be provided with upright wall. In this case, the inner surfaces of upright walls are preferably sloped outward from the bottom to permit the C05171 box walls to be "peeled back from the tile after the casting operation is complete. This permits the box to be removed without damage to the pattern on the tiles.

[103] After the box has been removed, the tile remains standing on base 714 and can be N1 transported using this base as a support.

[104] In a further improvement of the casting method, automatic injection moulding can N be used with an openable box as in Figure 7 adapted for automatic operation. The tile mixture can be injected through an injection aperture. The top cover can include one or N more fill indication apertures which can in turn be associated with corresponding fill sensors. As the mixture enters the fill apertures, the sensors are operated by the rising mixture, and when all sensors are tripped, the fill process is stopped. Additional vents may be included, particularly in the region of the corners or other regions where air may become trapped, to permit trapped air to be vented. The vents may be sufficiently small to vent air but to prevent the mixture from escaping. Between injection operations, the vents and apertures can be cleared by appropriately sized pins and/or a washing operation.

[105] The vents and apertures are preferably located on the edges so that they do not interfere with the pattern. However, in the case where complex patterns are used, small vents may also be provided in association with the patterned faces.

[106] Figure 8 is a schematic illustration of a method of manufacturing tiles which can be adapted for use in a horizontal extrusion process. The tile clay is extruded from the extrusion head 802, but, for clarity, is omitted from Figure 8 until stage 7 where the extruded stamped tile is shown at 832.

[107] The clay is extruded onto a first box sectio .n having its major plane 804 horizontal.

This surface has a first embossing pattern. The box section has side walls 806, 808. A second box section 812 is then pressed down on the clay. The second box section has walls 814, 816. The inner surface 812 can also be patterned in the same or a different pattern from that of the surface 804. As shown in Figure 8, the side walls are connected to the patterned faces in opposed pairs. However, this is not essential, and the side walls may be connected in different configurations, such as in contiguous pairs of adjacent side walls C05171 16 tt forming a corner, or with three sides connected to one patterned plate and the other side Sconnected to the other patterned plate, or all four sides may be connected to plate 812.

Further, the side walls may be independent of the patterned plates. Preferably, the lower plate 804 has the side facing the extrusion head 802 open to permit the clay to be extruded N onto the plate.

[108] Stage 1: The extrusion nozzle 802 is shown in partial view with the major N dimension oriented horizontally. A first patterned plate 804 receives the clay extrudate Cc from the nozzle 802. This plate 804 forms part of a dis-assemblable moulding box 820.

t Side walls 806, 808 are shown as attached to the plate 802, but they may be independent or they may be attached to the second patterned plate 812. Similarly, side walls 814, 816 are shown as attached to second plate 812, but may also be independent thereof. In the embodiment shown, the side walls 614, 816 are shown as having flared ends such as 818.

[109] Stage 2: Flying cutter 810 is provided and operates in a similar manner to that described with reference to the earlier embodiments to cut off the tiles at the required length, leaving the clay blank on plate 802.

[110] Stages 3 4: The second plate 812 is then closed over the clay on plate 802 to form a moulding box 820. The plates are pressed on the clay blank with sufficient force to ensure the top and bottom patterns are impressed into the clay. The side walls 806, 808, 814, 816 prevent theclay from spreading under the moulding pressure.

[111] After the clay has been moulded, the tile is rotated onto an edge, the blank is ejected from the box 820 and conveyed to the drying and baking stages (not shown).

[112] Stage 5: In this embodiment, one of the side walls 806 is removed as shown by arrow 822.

[113] Stage 6: The box 820 is rotated to stand on a conveyor 830 on the end from which wall 806 was removed.

C05171 17 tn [114] Stage 7: The tile is then ejected from the box 820. This is indicated in the embodiment shown in Figure 8 by the plates 802, 812 and associated side walls moving apart from the tile as indicated by arrows 826, 828.

CI [115] This technique can be used in conjunction with a continuous extrusion process by synchronizing the stamping/moulding process speed to match the extrusion rate from _extrusion head 802. Thus the bottom plate 804 is returned to receive the extrudate and the stamping/moulding process is synchronized with the extrusion speed.

t¢ [116] In an alternative, the side wall 806 may be left in place while the tile is rotated, and used as a stand for the tile when the plates 804, 812 and the other side walls are removed.

[117] The embodiment of the invention shown in Figures 9 10 provides analternative means for using a horizontal extrusion process in the manufacture of double sided tiles in plan view and side view respectively.

[118] The extrusion head 901, 1001, extrudes the clay 902, 1002 in a horizontal orientation onto conveyor 900, 1000, and the extruded preform having the desired width is then cut into the desired lengths by the flying cutter 903, 1003 to form the tile blanks.

[119] Clamp bars 904, 1004 then grip the tile blank at a pair of opposed edges and lifts the tile blank (cf clamp bars 1104, 1106 in Figures 11 12) from conveyor 900, 1000 onto the press loading conveyor 909, 1009 which conveys the tile blank between the upper patterning press 905, 1005 and the lower patterning press 1010. The upper and lower presses then imprint their patterns on the tile 906 which is conveyed out of the to the erecting mechanism 907, 1007 for erecting to stand on an edge on drying conveyor 908, 1008 which conveys the tiles to the drying stage.

[120] Preferably, the clamp bars are of smaller width than the thickness of a tile.

[121] The patterning press can be configured to press single tiles at one time or to press two or more tiles simultaneously. Where two or more tiles are to be pressed simultaneously, the clamp bars can be made of sufficient length to lift the number of tiles C05171 18 to be pressed simultaneously. Similarly, the erecting mechanism 907, 1007 can be Sdimensioned to handle the number of tiles being pressed simultaneously.

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[122] Because the clamp bars 904, 1004 lift the tile clear of the conveyor 900, 1000, the C clamp means can have a different travel speed compared with the conveyor 900, 1000, thus enabling the tiles to be the spaced apart.

[123] The thickness of the tile extrusion in Figure 10 is shown as enlarged for clarity and Cc is not to scale.

In [124] Figures 11 shows the clamp bars 1104, 1106 before they have clamped on to the tile 1102, while Figure 12 shows the clamp bars clamping the tile with the tile lifted through height [125] Figure 13 shows an embodiment of the erecting mechanism 1300 in the form of a roller deck made up of an array of rollers 1302. The deck can be provided with a pivot axis, 1304, 1306 around which the deck can rotate to turn the tiles on edge on the drying conveyor 908, 1008. The rollers can be padded.

[126] The operation of the clamp bars 9004, 1004, the press plates 905, 1005, 1010, and the erecting mechanism and the drying conveyor can be synchronized with the extrusion speed and flying cutter as with the other embodiments of the invention.

[127] Figure 14 illustrates a double sided tile extrusion line 1400 in accordance with an embodiment of the invention. An extrusion machine, illustrated as 1402, has an extrusion head 1404 and produces a continuous extrusion of tile material 1406 which is dissected into tile blanks 1410 by the flying cutter 1418. The speed of the extrusion is monitored by measuring the speed of the free wheeling conveyor 1414, and this can be used to synchronize the extrusion rate and the various downstream operations such as the flying cutter 1408, conveyors and pattern press.

C05171 19 n [128] The tile blanks are transferred to tile transporting and separating conveyors 1412, S1416. The downstream conveyor 1416 can run at a slightly greater speed than upstream conveyor 1412, or can have a two speed operation to separate the tile blanks.

C1 [129] The pressing of the tiles occurs in a tile press including fixed border frame 1422, an upper platten 1418 and a lower platten 1420. The tile blank is transferred to the press via a _transfer mechanism 1424 which is illustrated as a pair of parallel arm which are adapted to grip a pair of opposite edges of the tile and carry the tile into and from the tile press. The Cc transfer mechanism can be adapted to move in three orthogonal directions to perform press tN loading and unloading operations, to grip the tiles and raise and lower them and to transfer the tiles as required.

[130] When the tile has been pressed, it is transferred to an erecting device 1428, 1430 which stands the tiles on edge for transfer to the drying and firing stages.

[131] Figure 15 illustrates the operation of the tile press of Figure 14. The operation of the press is set out below.

[132] Stage 1. When the press is ready to receive a tile blank, the lower platten 1420 is located within the fixed border frame 1422. The upper surface of the lower platen 1420 is slightly raised above the top edge of the border frame 1422.

[133] The arms of transfer mechanism 1424 are initially spaced apart to permit the tile blank on the transfer conveyor 1416 to fit between the arms which extend beside the conveyor to receive the tile blank. When the tile blank is located between the upstream ends of the transfer mechanism 1424, the arms move to grip the edges of the tile blank and transfer it onto the upper surface of the lower platen 1420, which protrudes above the border frame 1422.

[134] The arms of the transfer mechanism 1424 move apart to permit the tile blank to be lowered into the border frame 1422 and to avoid contact with the platten 1418.

C05171 t [135] Stage 2. The lower platen 1420 descends to lower the tile blank into the border Sframe 1422. The upper platen 1418 descends onto the tile blank.

(-i [136] Stage 3. The upper and lower tile patterns are impressed into the tile blank by the upper platen 1418 and the lower platen.

[137] Stage 4. The platens 1418, 1420 are raised to lift the patterned tile clear of the border frame 1422 and the upper platen 1418 moves higher to permit removal of the Cc patterned tile from the lower platen 1420. The arms of the transfer mechanism 1424 move t inwards to grip the patterned tile and then the lower platen descends so the tile is clear of both platens and is held by the transfer mechanism 1424.

[138] The transfer mechanism transfers the patterned tile 1426 to the erecting device 1428, 1430 whichtilts the tile on edge for transfer to the drying and firing processes. The contact surface of the erecting mechanism can be padded.

[139] While the invention has been described by reference to particular combinations of integers, the invention is to be understood as involving combinations of one or more of the underlying features described and is not limited to the embodiments described.

Claims (39)

1. A tile including a pair of opposed faces, wherein a pattern is formed on each of the opposed faces.

2. A tile as claimed in claim 1 wherein at least one pattern is a relief pattern. N

3. A tile as claimed in claim 1, wherein the or each pattern is impressed into the tile. t

4. A tile as claimed in claim 1, wherein the pattern on one face is a relief pattern and the pattern on the other face is impressed into the tile. i

5. A tile as claimed in claim wherein the tile is made by a casting process. A tile as claimed in claim 1, wherein the tile is made inby an extrusion process.

6. A tile as claimed in claim 1, wherein the tile is made in an extrusion process.

7. A method of manufacturing tiles from a tile forming material, the tiles having a first and second opposed faces and three or more edges, the method including: preparing the tile forming material in aplastic state such that the material will not slump during processing; and imprinting a pattern on each of the major faces.

8. A method as claimed in claim 7, wherein the tile is supported on one of its edges until is has been at least partially dried.

9. A method as claimed in claim 7 or claim 8, including: extruding a continuous column of tile forming material in said plastic state; the column having an extrusion speed and an extrusion direction; impressing a pattern on each of the opposed faces using pattern printing plates; causing the plates to move at the extrusion speed and in the extrusion direction for the duration of the time the plates are in contact with the column. C05171 22 S

10. A method as claimed in claim 9, wherein the plates are formed on the cylindrical Ssurface of first and second rollers, the first roller being applied to the first face of the column, and the second roller being applied to the second face of the column. N

11. A method as claimed in claim 10, wherein the line of contact of between the first roller and the column is directly opposite the line of contact between the second roller and _the column. C

12. A method as claimed in any one of claims 9 to 11 wherein the force applied to the t column by the first plate is substantially equal and substantially opposite to the force applied to the column by the second plate.

13. A method as claimed in any one of claims 9 to 12 including performing a cutting operation to cut the tiles to a predetermined length using a cutter; and causing the cutter to move at the extrusion speed and in the extrusion direction for the duration of the cutting operation.

14. A method as claimed in claim 13 including the step of depositing the cut tiles in a substantially upright orientation on one of the edges of the tile onto a support base.

A method as claimed in claim 14, including drying the tiles while the tiles are in the substantially upright orientation.

16. A method as claimed in any one of claims 9 to 15, including extruding the column in a substantially upright orientation.

17. A method as claimed in any one of claims 9 to 16, the extrusion speed being substantially constant.

18. A method as claimed in any one of claims 9 to 17, including synchronising the cutting operation with the extrusion speed. C05171 23

19. A method as claimed in any one of claims 9 to 18, including synchronising the pattern printing operation with the extrusion speed.

A method as claimed in claim 9, including the steps of extruding the tile forming material so that the major plane of the extrudate oriented so that it is not in the vertical plane, and forming a pattern on each face of the extrudate while it is in the non-vertical orientation.

21. A method as claimed in claim 20, including the step of cutting the extrudate to a predetermined length before the step of forming a pattern on each face of the tile.

22. A method as claimed in claim 20 or claim 21, including the steps of gripping the tile by its edges and conveying it to a pressing station, conveying the pressed tile to an erecting station and erecting the tile on one of its edges.

23. A tile extruding machine including a die to form an elongated extrudate of tile forming material; an extrusion driving mechanism to force tile forming material in a plastic state through the die at an extrusion speed; first and second pattern printing plates to print a pattern adapted to fit the width dimension of the column, and print a pattern on respective first and second sides of the column.

24. A tile extruding machine as claimed in claim 23, including first drive means to drive the printing plates to move in synchronism with the column during the printing operation.

A machine as claimed in claim 24 including synchronizing means to synchronise the movement of the printing plates with the speed of the column.

26. A machine as claimed in any one of claims 23 to 25, wherein the first and second plates are formed on the cylindrical faces of first and second rollers respectively. C05171 24 S

27. A machine as claimed in claim 26, wherein the line of contact between the first roller and the column is directly opposite the line of contact between the second roller and (Ni the column.

28. A machine as claimed in claim 27, wherein the force applied to the column by the first plate is substantially equal and substantially opposite to the force applied to the _column by the second plate. (Ni Cc

29. A machine as claimed in any one of claims 23 to 28, including a cutter adapted to t cut the tiles to predetermined lengths in a cutting operation.

A machine as claimed in claim 29, including second drive means to drive the cutting means to move in the direction of and at the speed of the column for the duration of the cutting operation.

31 A machine as claimed in claim 29 or claim 30, wherein the column is extruded in a substantially upright orientation, the machine including a support base which supports the tiles on an edge as they are cut from the column.

32. A machine as claimed in claim 31, wherein the support base is part of a conveyor.

33. A machine as claimed in any one of claims 29 to 232 as appended to claim wherein the synchronizing means synchronizes the speed of the cutter with the speed of the column during the cutting operation.

34. A tile gripping mechanism substantially as herein described with reference to the accompanying drawings.

A tile erecting mechanism substantially as herein described with reference to the accompanying drawings.

36. A flying cutter substantially as herein described with reference to the accompanying drawings. C05171

37. A tile printing mechanism substantially as herein described with reference to the accompanying drawings.

38. A tile extruder adapted to extrude tile extrudate having its major plane substantially upright.

39. A tile forming machine substantially as claimed in any one of claims 23 to 30, the machine being adapted to extrude and press tiles in a substantially horizontal orientation. A method of forming tiles as claimed in claim 7, wherein the tiles are extruded and pressed with the major plane substantially horizontal. Dated this 2nd day of December 2005 Australian Natural Tile Company Pty Ltd by their patent attorneys Halford Co