STACKING OF BRICKS

THIS INVENTION relates to the stacking of bricks. More particularly it relates to a method of manipulating bricks to produce a stack of bricks, and to a brick stacking installation.

After manufacture, building bricks are manually or mechanically packed into stacks. Manual packing allows the bricks to be packed in a staggered configuration so that the stack is stable and resistant to collapse particularly when being transported. However, mechanical stacking equipment known to the Applicant does not produce stacks in which the individual layers of bricks of the stack are staggered in such a way that the stack is stable. The stacks produced by present stacking equipment either have to be wrapped or tied to prevent them from collapsing or they have to be manually unpacked and repacked in order to produce stable stacks. When cement stock bricks are manufactured, it is necessary for them to cure before they can be handled. The bricks are generally placed on wooden pallets for curing and, once cured, are destacked in order to make the wooden pallets available for further production runs. The partially cured bricks are usually destacked and packed in a storage area where they are allowed to cure further until the required hardness has been reached. This curing and destacking cycle should preferably be as short as possible to reduce the amount of pallets which are required to produce the bricks. The cured bricks are usually packed manually with the "wide" side down and so that each layer of the stack is staggered with respect to the layer below it, in order to produce a stable stack that can be loaded and transported without collapsing. The present invention provides a

method of manipulating bricks to produce a stack of bricks, and an installation for stacking bricks in a stable staggered arrangement.

According to a first aspect of the invention, there is provided a method of manipulating bricks to produce a stack of bricks, the method including lifting bricks under reduced pressure from a feed zone, and depositing them in successive layers in a stacking zone, thereby to form a stack of bricks comprising a plurality of layers of bricks.

The lifting of the bricks under reduced pressure may include engaging the bricks with suction cups, reducing the pressure in the suction cups so that the suction cups adhere to the bricks, and lifting the suction cups so that the bricks are lifted with the suction cups.

The reduction in pressure in each suction cup will thus be sufficient to support the weight of the brick. At least the edge portions of the suction cup which come into contact with the brick will preferably be of a deformable material so that the seal formed between the brick and the suction cup is sufficient to maintain a reduced pressure in the suction cup to allow the brick to be lifted when the pressure in the suction cup has been reduced.

The method may include providing an array of the suction cups, with each suction cup engaging a brick of a corresponding array of bricks so that the array of bricks is thus lifted when the array of suction cups is lifted.

The method may include moving the suction cups, with the bricks adhered thereto, from the feed zone to the stacking zone, and, in the stacking zone, restoring the pressure in the suction cups, so that the bricks are thereby released from the suction cups and deposited on a support.

The method may include arranging the array of bricks on the support to form a first layer and forming successive layers of bricks on top of the first layer, to form a brick stack on the support.

The stack may include a plurality of brick layers, each layer comprising a planar abutting arrangement of bricks, in which at least some of the bricks of one layer are staggered with respect to bricks of an adjacent layer.

The method may include the steps of forming, in the stacking zone, first and second brick layers by lifting first and second pre-selected groups of bricks of a primary layer of bricks which are, in the feed zone, in an initial alignment in which the bricks are arranged in side-by-side rows, rotating one group through approximately 90 ^° with respect to the other, and placing them one on top of the other, so that the second brick layer is uppermost.

The method may include forming the primary layer of bricks by arranging the bricks thereof in the side-by-side rows.

The method may include forming a third brick layer by mechanically lifting a further pre-selected group of bricks of the primary layer, aligning it so that its bricks are aligned with the bricks of the first brick layer, and locating it on top of the second brick layer.

As this process is repeated, the stack will be formed by successively locating further groups of bricks of the primary layer on the last formed brick layer with the bricks of each further group of bricks aligned with the bricks of the last but one brick layer.

However, because bricks have a rectangular plan profile, an array or layer of bricks arranged in side-by-side rows will also have a rectangular plan profile, and stacking such arrays or layers one on top of the other with one layer rotated by 90° with respect to the next layer will produce stacks which have a stepped or crenellated side profile. In addition, this method produces a stack which has a line of weakness extending from top to bottom down the middle of the stack in which there is no overlap of bricks in successive rows. It would therefore be preferable if each of the bricks of a stack could be staggered with respect to the bricks above and/or below it and if the entire stack had a smooth side profile and not a stepped side profile.

Accordingly, the method may instead include the steps of in a feed zone, selecting a first group of bricks of a primary layer of bricks which are in an initial alignment in which the bricks are arranged in side-by-side rows, lifting sub-groups of the first group of bricks, re-aligning the sub-groups relative to one another and placing them on a support, to form a first brick layer; and selecting a second group of bricks of the primary layer, lifting subgroups of the second group of bricks, re-aligning the sub-groups relative to one another, and placing them on top of the first brick layer to form the second brick layer.

The sub-groups of bricks of the first and second groups of bricks may be matching sub-groups.

The method may include forming the second brick layer so that the alignment of its bricks is approximately 90 ^° with respect to the alignment of the bricks of the first brick layer. The method may then also include forming successive brick layers so that the bricks of each newly formed layer are aligned approximately 90° with respect to the bricks of the preceding layer.

Either method may include forming the primary layer by arranging the bricks to be stacked in side-by-side rows with the bricks of at least some of the rows in staggered positions relative to the bricks of adjacent rows.

For example, the first group of bricks of the primary layer may comprise thirty two bricks arranged in rows of four and the sub-groups may comprise, respectively, a first and a second set of six bricks and a third set of twenty bricks. Each set of six bricks may comprise three bricks of a first row of the primary layer, two bricks of a second row of the primary layer, and one brick of a third row of the primary layer, and the third set of twenty bricks may comprise, respectively, four bricks from each of a first two rows of the primary layer, three bricks from each of a second two rows of the primary layer, two

bricks from each of a third two rows of the primary layer and one brick from each of a fourth two rows of the primary layer.

The first and second sets of six bricks may be generally triangular in plan profile and the third set may be broadly X-shaped in plan profile. Forming the first stack layer may include mechanically lifting the first, second and third sets, rotating them relative to one another, and placing them on the support so that the first and second sets of six bricks are rotated by approximately 90 ^° relative to the third set of twenty bricks when compared with the initial alignment of the first, second and third sets in the primary layer and so that the three sets form an interlocking layer.

Forming the primary layer of bricks may include arranging the bricks in the side-by-side rows.

A brick conventionally has operatively upper and lower large faces which are symmetrically identical and which are the largest faces of the brick, side faces which are smaller than the largest faces and end faces which are smaller than the side faces. More specifically, in the primary layer, each brick may rest on one of its large faces.

The bricks of at least some of the rows in the primary layer may be in staggered positions relative to the bricks of adjacent rows.

Forming the primary layer of bricks may include arranging the bricks in the side-by-side rows on a first movable surface, such as the surface of a conveyor belt, and displacing the rows of bricks by moving the first movable surface towards a stop formation which has a staggered profile and which is shaped so that, as the moving rows of bricks come into contact with the stop formation, the rows are stopped in a pre-selected order, so that some rows continue to move after others have stopped moving and so that, when all of the rows have been stopped by the stop formation, at least some of the adjacent rows of bricks are in a staggered alignment.

In one embodiment of the invention, the method may include displacing eight rows of bricks on the first movable surface, with the stop formation being shaped so that the first and eighth rows are together stopped first, then together the second and seventh rows, then together the third and sixth rows, and then together the fourth and fifth rows and so that each row is staggered with respect to its adjacent row or rows except for the fourth and fifth rows in which the bricks of the fourth row are aligned with the bricks of the fifth row.

However, in another embodiment of the invention, the method may include displacing eight rows of bricks on the first movable surface, with the stop formation being shaped so that the fifth, sixth and seventh rows are stopped successively, then the first and eighth rows together, and then the second, third and fourth rows successively, and so that each row is staggered with respect to its adjacent row or rows except for the fourth and fifth rows in which the bricks of the fourth row are aligned with the bricks of the fifth row.

Arranging the rows of bricks in the side-by-side rows on the first movable surface with each brick resting on one of its large faces may include positioning a second movable surface at a right angle to the first movable surface, arranging rows of bricks on their large faces on the second movable surface so that their side faces are aligned in the direction of movement of the second movable surface and, with the first movable surface in a stationary state, displacing the second movable surface towards the stationary first movable surface so that the rows of bricks on the second movable surface are deposited in rows on the first movable surface with an end face of each brick aligned in the direction of movement of the first movable surface.

The method may include the prior step of arranging rows of bricks on their side faces on a support having an edge, with the large faces of the bricks aligned with the edge, positioning and aligning the second movable surface adjacent the edge so that, when it moves, it moves at a right angle away from the edge and, with the second movable surface moving away from the edge, successively tipping the rows of bricks from the support over the edge and onto the second movable surface so that the bricks land on the second

movable surface on their large faces with their side faces directed in the direction of movement of the second movable surface.

The support may be in the form of a pallet while the edge may be an edge of the pallet. The method may then include arranging bricks on a plurality of pallets on their side faces in side-by-side rows, arranging a plurality of pallets in a stack and tipping the rows of bricks on successive pallets in the stack onto the second movable surface by incrementally raising the stack and tipping the bricks of successive pallets of the stack onto the second movable surface as each pallet reaches a position in which an edge of that pallet is adjacent the second movable surface.

The support on which the first brick layer is formed may be provided by a base layer of bricks arranged in side-by-side rows on their side edges. The method may thus include the prior step of arranging the base layer of bricks in side- by-side rows on their side faces to provide a base for the stack.

The method may include effecting the arrangement of the base layer on a third movable surface. The third movable surface may be positioned next to the first movable surface and being arranged to move parallel with the first movable surface.

Arranging the base layer may thus include positioning a fourth movable surface at right angles to the third movable surface, arranging rows of bricks on their side faces on the fourth movable surface and, with the third movable surface in a stationary state, displacing the fourth movable surface so that the rows of bricks on the fourth movable surface are deposited on the third movable surface on their side faces and so that their large faces are aligned at right angles to the direction of movement of the third movable surface.

Arranging the rows of bricks on their side faces on the fourth movable surface may include arranging rows of bricks on their side faces on supports so that their large faces are aligned in the direction of movement of the fourth movable surface and displacing the rows onto the fourth movable surface.

The supports may be in the form of pallets as hereinbefore described, and the method may, as hereinbefore, include incrementally raising a stack of pallets and successively displacing the bricks on each pallet onto the fourth movable surface to produce the alignment described above.

According to a second aspect of the invention, there is provided a brick stacking installation which includes brick stacking apparatus configured to lift bricks under reduced pressure from a feed zone and to deposit them in successive layers in a stacking zone.

The brick stacking apparatus may includes an array of suction cups, with each suction cup adapted to engage a surface of a brick, and pressure reducing means for reducing the pressure in the suction cups so that they adhere to the bricks.

The pressure reducing means may include a vacuum pump to which the suction cup is connected or connectable in flow communication. The seals between the suction cups and the bricks will naturally be good enough to permit the pressure in the suction cups to be reduced sufficiently to support the weight of the bricks and thereby permit the bricks to be lifted by lifting the suction cup.

Each suction cup may include a body and a flexible peripheral lip which is mounted on, or forms part of, the body and which provides a brick engaging surface. The body and the lip may be of different materials. For example, the body may be formed of a silicone rubber with a Shaw hardness of about 80. A preferred silicone rubber is NPS 80 Shore Black™ as supplied by Carlin Medical Extrusions (Pty) Limited in South Africa. The lip may also be formed of a silicone material. It may be formed of a closed cell silicone film sheet material of the type supplied by Carlin Medical Extrusions (Pty) Ltd. The lip may be secured to the body with a silicone based bonding agent. The suction cup may instead be fabricated from a rubber material. For example it may be

fabricated from Moss™ rubber as supplied by Schmalz GmbH or from a closed cell rubber material.

A suction cup support to which the suction cups are connected to permit the bricks to be lifted simultaneously, may be provided.

The installation may include supply means configured to supply bricks to the feed zone in a predetermined configuration; and with the brick stacking apparatus being configured to arrange the bricks, after lifting them from the feed zone, into a new configuration which is different to the configuration they were in in the feed zone and deposit them in the new configuration in successive layers in the stacking zone.

The brick stacking apparatus may include at least two lifting heads, each of which is configured to lift a plurality of bricks, with the lifting heads being relatively displaceable. This arrangement permits a first set of bricks lifted by one head to be displaced relative to a second set of bricks lifted by the other lifting head thereby permitting the bricks to be deposited in the stacking zone in the new configuration which is different to the configuration they were in in the feed zone.

As mentioned above, when the bricks are manufactured, they are placed on pallets resting on their side faces. The brick containing pallets are then stacked one on top of the other to form a pallet stack.

The supply means may include a first conveyor arrangement for conveying bricks to the feed zone.

The supply means may further include destacking means for displacing bricks from a pallet onto the first conveyor arrangement. The destacking means may include a pallet stack support which is positioned adjacent to the first conveyor arrangement and which is vertically displaceable in increments corresponding to the height of each layer of the pallet stack and displacement means for

displacing a layer of bricks off the pallet on which they are supported onto the first conveyor arrangement. The destacking means may also include an indexing arrangement configured to control the operation of the pallet stack support such that a pallet from which the bricks are to be displaced onto the first conveyor arrangement is positioned at a level which is above the level of the first conveyor arrangement so that as the bricks are displaced from the pallet they are tilted onto their large faces. The destacking means may thus be a destacker.

The supply means may include a second conveyor arrangement for feeding pallet stacks from a supply of pallet stacks to the destacking means.

The brick stacking apparatus may also include a lifting head support on which the lifting heads are mounted and which is displaceable between the feed zone and the stacking zone.

More particularly, a central lifting head and two lateral lifting heads may be mounted on the lifting head support, with the lateral lifting heads being positioned on opposite sides of the central lifting head.

The lifting head support may be angularly displaceable about a vertically extending axis.

The lateral lifting heads may be angularly displaceable about vertical axes between first and second positions.

Each lifting head may be hollow, and with the vacuum pump and suction cups may be in flow communication with the interior of the lifting heads.

When the lateral lifting heads are in their first positions, the suction cups on the central lifting head may be parallel to those of the lateral lifting heads. When the lateral lifting heads are in their second positions, the suction cups on the lateral lifting heads may be perpendicular to the suction cups on the central lifting head.

At least one of the central lifting head or the lateral lifting heads may be vertically displaceable relative to the lifting head support between a rest position, towards which it or they are biased, and a displaced position, such that in the rest position, the central lifting head is positioned at a level which is different to the level of the lateral lifting heads thereby permitting unobstructed angular displacement of the lateral lifting heads by the central lifting head.

The first conveyor arrangement may include a first movable surface for conveying bricks arranged in parallel rows into the feed zone, the installation including a stop formation positioned above the first movable surface against which the lead bricks in each row abut.

The stop formation may have a staggered profile and is shaped so that, as the moving rows of bricks come into contact with the stop formation, the rows are stopped in a pre-selected order, so that some rows continue to move after others have stopped moving and so that, when all of the rows have been stopped by the stop formation, at least some of the adjacent rows of bricks are in a staggered configuration.

The first conveyor arrangement may include a second movable surface which extends perpendicular to the first movable surface and which conveys bricks from the destacking means to the first movable surface. The first and second movable surfaces may be provided by conveyors.

The stack of bricks which is to be formed will typically have a first or base layer comprising a plurality of bricks arranged in a plurality of rows with adjacent bricks in each row having their end faces in abutment and with adjacent bricks in adjacent rows having their largest faces, in abutment. To this end, the supply means may include a second conveyor arrangement for conveying bricks to form a first layer of a stack to the stacking zone.

The supply means may include a second destacking means for displacing bricks from a pallet forming part of a pallet stack onto the second conveyor

arrangement. The second destacking means may include a pallet stack support which is positioned adjacent to the second conveyor arrangement and which is vertically displaceable in increments corresponding to the height of each layer of the pallet stack and displacement means for displacing a layer of bricks off of the pallet on which they are supported onto the second conveyor arrangement. The second destacking means may thus be a destacker.

Instead, the supply means may include a base brick lifter for displacing bricks from a pallet forming part of a pallet stack onto the second conveyor arrangement.

The base brick lifter may include a hoist assembly, a suction assembly which includes a plurality of suction cups, and a vacuum pump operably connected to the suction cups, so that bricks can be displaced from the pallet to second conveyor arrangement by engaging the suction cups with bricks on the pallet, reducing the pressure in the suction cups so that they adhere to the bricks, lifting the suction cups and the bricks attached thereto, transferring the bricks to the second conveyor arrangement, and restoring the pressure in the suction cups, to release the bricks on to the second conveyor arrangement.

The invention is now described in more detail, by way of example, with reference to the accompanying diagrammatic drawings. In some of the drawings, some details have been omitted for clarity.

In the drawings,

FIGURE 1 shows, schematically, a plan view of one embodiment of a brick stacking installation for stacking bricks according to the method of the invention;

FIGURES 2 and 3 are schematic plan views of bricks arranged on conveyor belts with end stops;

FIGURE 4 is a schematic side view of a stack of bricks formed with the installation of Figure 1 ;

FIGURE 5 is a schematic plan view of a layer of bricks of the stack of Figure 4;

FIGURE 6 is a plan view of two layers of bricks packed differently from the bricks of Figure 4;

FIGURE 7 is a side view of a stack of bricks packed as illustrated in Figure 6; FIGURE 8 shows a stack of pallets, for use in the installation of Figure

1 ;

FIGURE 9 shows a side view of brick stacking apparatus forming part of the brick stacking installation of Figure 1 ;

FIGURE 10 shows a plan view of the brick stacking apparatus of Figure 9;

FIGURE 1 1 shows a bottom view of the lifting heads forming part of the brick stacking apparatus of Figure 9;

FIGURE 12 shows a plan view of part of the brick stacking apparatus of Figure 9; FIGURE 13 shows a plan view of a turntable forming part of the brick stacking apparatus of Figure 9;

FIGURE 14 shows a sectional side view of a track for the turntable of Figure 13;

FIGURE 15 shows a side view of a mechanical destacker forming part of the brick stacking installation of Figure 1 ;

FIGURE 16 shows a plan view of the destacker of Figure 15;

FIGURE 17 shows a sectional view of a lifting head taken at XVII - XVII in Figure 1 1 ;

FIGURE 18 shows a plan view of a suction cup forming part of the brick stacking apparatus of Figure 9;

FIGURE 19 shows a side view of the suction cup of Figure 18;

FIGURE 20 is another schematic plan view of bricks arranged on a conveyor belt of the brick stacking installation of Figure 1 ;

FIGURE 21 shows, schematically, a plan view of another embodiment of a brick stacking installation for stacking bricks according to the method of the invention;

FIGURE 22 shows a front elevation of the installation of Figure 21 ;

FIGURE 23 shows an end view of the destacker of the installation of Figure 21 ;

FIGURE 24 shows an enlarged view of part of the destacker of the installation of Figure 21 ;

FIGURE 25 shows an enlarged side view of a hoist assembly of a base brick lifter of the installation of Figure 21 ; FIGURE 26 shows a plan view of the hoist assembly of Figure 25;

FIGURE 27 shows a sectional view through XXVII-XXVII of Figure 26;

FIGURE 28 shows a plan view of a layer of bricks on a pallet forming part of a pallet stack located on the first base brick conveyor of the installation of Figure 21 , with the side plates of the suction header shown in position relative to the bricks, in two sequential positions of the suction header; and

FIGURES 29 to 33 show, in plan view, the sequential formation of a base brick layer on the second stacking conveyor of the installation of Figure 21 , using the base brick lifter, and with the side plates of the suction header shown on some of the figures.

Referring to Figures 1 to 20 of the drawings, reference numeral 10 generally indicates a brick stacking installation in accordance with one embodiment of the invention. The installation is shown schematically in the drawings.

The installation 10 includes a seven-tier brick conveyor 12, a transfer conveyor 14, a mechanical destacker 16, a brick tilt conveyor 18, a first stacking conveyor 20, a second stacking conveyor 22, a first base brick conveyor 24, a second base brick conveyor 26 and a base brick destacker 28. Two brick stackers 30, 32 are mounted to extend over the first and second stacking conveyors 20, 22 and in use, as described in further detail below, transfer bricks from a feed zone defined on the first stacking conveyor 20 to a stacking zone defined on the second stacking conveyor 22. In addition, the installation 10 includes empty pallet chutes 17 and 29 positioned adjacent the mechanical destackers 16 and 28.

In different embodiments of the invention (not shown), the installation 10 may have only one brick stacker or more than two depending on specific requirements.

In use, freshly manufactured bricks 33, particularly cement bricks, are packed on pallets 34 as shown in Figure 8, and the packed pallets 34 arranged in pallet stacks 36 comprising seven packed pallets. Each pallet 34 typically holds 54 bricks arranged in rows in a six by nine arrangement so that each seven-tier stack 36 contains 378 bricks.

Naturally, in different embodiments of the invention, the stacks may contain more or fewer pallets and each pallet may hold more or fewer bricks.

Each brick 33 comprises a pair of large faces which are identical and extend parallel to each other, a pair of side faces which are smaller than the large faces and which extend parallel to each other, and a pair of end faces which are smaller than the side faces and which extend parallel to each other.

The bricks on each pallet 34 are placed on one of their side faces and, with reference to Figure 1 , the pallets stacked so that large faces of the bricks face in the direction of the arrow 31 in which the stacks 36 are conveyed by the conveyor 12. The stacks 36 of pallets 24 are conveyed by the seven tier brick conveyor 12 to the transfer conveyor 14. Each stack 26 is conveyed by the transfer conveyor 14 in the direction of the arrow 35 to the mechanical destacker 16.

As can best be seen in Figures 1 , 15 and 16 of the drawings, the mechanical destacker 16 is positioned next to the brick tilt conveyor 18. As can best be seen in Figures 15 and 16 of the drawings, the mechanical destacker 16 includes a support structure, generally indicated by reference numeral 70 and a pallet stack support, generally indicated by reference numeral 72. The pallet stack support 72 includes a frame, generally indicated by reference numeral 74 on which a plurality of parallel rollers 76 is mounted to form a horizontal support surface.

The support 72 is vertically displaceable between a lowered position (shown in Figure 15 of the drawings) in which a pallet stack 36 is receivable from the

transfer conveyor 14 onto the support, and a raised position. To this end, two shafts 78 are mounted on the frame 74 in a spaced apart parallel configuration. An electric motor 80 is mounted on the frame 74 and drivingly connected to the shafts 78. Four vertically extending racks 82 are mounted on the support structure 70 and two complementary pinion gears 84 are mounted on each of the shafts 78 such that they drivingly engage the racks 82.

The destacker 16 further includes displacement means, generally indicated by reference numeral 86 for displacing a layer of bricks 33 off the pallet 34 on which they are supported onto the brick tilt conveyor 18. The displacement means 16 includes a horizontally extending displacement member 88 from which a pair of spaced apart horizontally extending racks 90 protrude perpendicularly thereto. The displacement means 86 further includes an electric motor 92 mounted on the support structure 70 and drivingly connected to a shaft 94 on which a pair of complementary pinion gears 96 is mounted such that the gears 96 drivingly engage the racks 90 permitting displacement of the displacement member 88 in a horizontal plane as indicated by arrow 98.

The destacker 16 includes an indexing arrangement configured to control the operation of the motor 80. Hence, with the pallet stack support 72 is in its lowered position, a stack of pallets is fed from the transfer conveyor 14 onto the support 72. The stack 36 of the pallets 34 is lifted incrementally so that each pallet 34 of the stack 36 is successively aligned at a position about 20 mm above the brick tilt conveyor 18. In this position, the motor 92 is activated to displace the displacement member 88 horizontally and thereby displace the bricks on the aligned pallet 34 towards the edge of the pallet 34. As the bricks topple over the edge of the pallet onto the brick tilt conveyor 18 they are tilted onto one of their large faces with their side faces aligned in the direction of movement of the brick tilt conveyor 18, as depicted by arrow 38 (Figure 1 ), and are conveyed towards the first stacking conveyor 20.

The empty pallets are then transferred to the pallet chute 17 where they are retrieved by forklifts for re-use.

With the first stacking conveyor 20 stationary, the rows of bricks on the brick- tilt conveyor 18 are displaced by the conveyor 18 and deposited onto the first stacking conveyor 20 so that the bricks are still resting on one of their large faces but with end faces of theirs now directed in the direction of movement of the stacking conveyor, as shown by the arrow 40 (Figure 1 ).

The bricks, which are in a six by nine arrangement when tilted onto the brick- tilt conveyor 18, pass sensors (not shown) linked to logic controllers (not shown) which control movement of the conveyor 18 so that only eight rows of bricks (each row containing six bricks) are transferred to the stacking conveyor 20 and one row of six bricks remains on the brick-tilt conveyor 18. This row is retained by a displaceable stopper member (not shown). The retained row then forms part of the next set of bricks which is transferred to the stacking conveyor 20. In this way eight rows of bricks at a time are transferred to the conveyor 20.

At the same time, bricks are conveyed along the first base brick conveyor 24, in the direction of the arrow 42, towards the base brick destacker 28. The bricks on the first base brick conveyor 24 are arranged on pallets in stacks, as on the conveyor 12, in parallel rows on their side faces with large faces of theirs directed in the direction of movement of the first base brick conveyor 24, as depicted by the arrow 42. The destacker 28 works in the same way as the destacker 16 but the bricks are mechanically displaced onto the second base brick conveyor 26 without changing their alignment. Thus, the bricks on the second base brick conveyor rest on side faces with large faces facing in the direction of movement 27 of the conveyor 26. The empty pallets are again transferred to the pallet chute 29 and are retrieved by forklifts as for the pallet chute 17.

With the second stacking conveyor 22 stationary, the bricks on the second base brick conveyor 26 are then displaced onto the second stacking conveyor 22 so that they are aligned on the second stacking conveyor 22 on their side faces with their end faces directed in the direction of movement of the second

stacking conveyor 22, as depicted by the arrow 44. The bricks on the second stacking conveyor 22 are then conveyed to the brick stackers 30, 32.

When the bricks are delivered by the base brick conveyor 24 to the destacker 28, the destacker transfers thirty six bricks (four rows of nine bricks each) to the conveyor 26 and retains two rows of nine bricks. The conveyor 26 then moves forward to allow the retained batch of 18 bricks to be moved across to the conveyor 26. The empty pallet is ejected, the destacker rises to the correct height for destacking the next pallet and the sequence is repeated by first transferring two rows of nine bricks. The base brick conveyor 26 then moves forward and the remaining thirty six bricks are transferred to the conveyor 26. Fifty two bricks are then transferred to the stacking conveyor 22 at a time and these form a base for a stack of bricks. Control of this process is achieved through the use of sensors (not shown) and logic controllers (not shown), end-stops (not shown), accumulator stoppers (not shown) and by stopping and starting the various conveyors to position the bricks in the required locations for the following step in the sequence of operations.

Referring now to Figure 2, the first stacking conveyor 20 is provided with an end stop 50 at its end remote from the brick tilt conveyor 18. In the drawing, the rows of bricks on the first stacking conveyor 20 have been numbered from 1 to 8. The end stop 50 has a stepped shape, as can be seen in the drawings and, corresponding to the rows of bricks 1 -8, stop formations of the end stop 50 are correspondingly numbered 50.1 -50.8.

As the rows of bricks 1 - 8 are moved by the first stacking conveyor 20 in the direction of the arrow 40 towards the end stop 50, row 5 encounters the stop formation 50.5 first and is stopped. Rows 6 and 7 are then successively stopped by the stop formations 50.6 and 50.7. Rows 1 and 8 are then simultaneously stopped by the stop formations 50.1 and 50.8 and rows 2, 3, 4 are then successively stopped by the stop formations 50.2, 50.3 and 50.4. The bricks are then arranged as depicted in Figure 2. From the drawing it can be seen that the bricks of rows 4 and 5 are aligned side-by-side without any overlap whilst the rows 1 , 2, 3, 4 and 5, 6, 7, 8 have bricks arranged in a

longitudinally staggered arrangement relative to the bricks in the adjacent row or rows.

Referring now to Figures 9 and 10 of the drawings, the two brick stackers 30, 32, which together constitute brick stacking apparatus, are configured to lift bricks from a feed zone, generally indicated by reference numeral 1 10, and deposit them in successive layers in a stacking zone, generally indicated by reference numeral 1 12.

The brick stackers 30, 32 are substantially identical and accordingly only the brick stacker 30 is described in detail herebelow. As can be seen in Figures 9 and 10, the brick stacker 30 includes a support frame, generally indicated by reference numeral 1 14. The support frame 1 14 comprises posts 1 16 which extend upwardly in pairs on opposite sides of the feed zone 1 10 and stacking zone 1 12, and a pair of parallel horizontally extending tracks 1 18 which extend between corresponding posts 1 16 in the adjacent pairs such that they span the feed zone 1 10 and stacking zone 1 12. Further, the brick stacker 30 includes a carriage 120 which is slidably mounted on the tracks 1 18 for displacement between a first position in which it is positioned above the feed zone 1 10 and a second position in which it is positioned above the stacking zone 1 12. The brick stacker 30 includes a turntable 122 which is supported for angular displacement about a vertical axis in a turntable support 124. As can best be seen in Figures 10 and 14 of the drawings, the turntable support 124 is in the form of an annular radially inwardly open channel-shaped formation which is connected to the carriage 120 by four vertically extending posts 126.

As can best be seen in Figure 13 of the drawings, the turntable 122 includes a platform 128 on which a plurality of circumferentially spaced guide wheels 130 is mounted for rotation about radially extending axes. The guide wheels 130 run in the channel defined by the turntable support 124. In addition, three circumferentially spaced locating wheels 132 are mounted on the platform 128 for rotation about vertical axes. The locating wheels 132 abut against a radially inner surface of an annular collar 134 forming part of the turntable support 124 and serve to locate the turntable 122 to ensure that it rotates

about a vertical axis with little or no lateral movement. An electric motor 136 is mounted on the turntable support 124 and is drivingly connected to a pinion gear 138. The pinion gear 138 drivingly engages an arcuate gear segment or rack 140 mounted on the platform 128 to permit displacement of the platform through 90°.

With reference to Figures 9, 10 and 1 1 of the drawings, three lifting heads, namely, a central lifting head 142 and two lateral lifting heads 144, 146 are mounted to the platform 128 such that they are suspended therebelow. The lateral lifting heads 144, 146 are positioned on opposite sides of the central lifting head 142.

With reference also to Figures 17, 18 and 19 of the drawings, the central lifting head 142 includes a hollow body 148 having a horizontal top plate 150, a horizontal bottom plate 152, and a peripherally extending side plate 154 connected to and extending between the outer edges of the top plate 150 and the bottom plate 152. A plurality of reinforcement ribs 156 extend between the inner surfaces of the top plate 150 and bottom plate 152 to provide the lifting head 142 with the required rigidity. Twenty suction cups 158 are mounted to the underside of the bottom plate 152. Each suction cup 158 includes a rectangular base 160 and a peripheral lip 162 which protrudes downwardly from the base 160. The peripheral lip 162 has an end portion 163 which is more flexible than the remainder of the suction cup permitting it to conform to irregularities on the surface of the brick with which it is to engage. In this regard the base 160 and lip 162, other than the end portion 163, will typically be formed as a unitary moulding and have a hardness of about 80 Shaw. The end portion 163 will typically have a hardness of about 20 Shaw. Complementary openings 153, 161 are provided in the lifting head bottom plate 152 and the suction cup base 160 respectively so that the interior of the suction cup 158 is in flow communication with the interior of the body 148. As can best be seen in Figure 1 1 of the drawings, twenty suction cups 158 are arranged in eight parallel rows, the two outer rows comprising four longitudinally spaced suction cups. The innermost rows each comprise one suction cup 158 and the intermediate rows each comprise two and three

suction cups, respectively. Accordingly, as can best be seen in Figure 1 1 of the drawings, when viewed in plan, the central lifting head 142 has two parallel side edges 164 and two stepped side edges 166 which provide the central lifting head 142 with a waisted appearance. The central lifting head 142 is connected to the platform 128 by a tubular connector 168.

The lateral lifting heads 144, 146 are substantially identical in construction. Each lifting head 144, 146 comprises a hollow body 170 constructed in a similar fashion to the hollow body 148 of the central lifting head 142, and thus comprising a spaced apart top and bottom plates connected by side plates. Reinforcing ribs 177 are connected to the operatively inner surfaces of the bottom and top plates to provide the lifting heads with the required rigidity. Six suction cups 158 are connected to the operatively under surface of the bottom plate of each lifting head 144, 146 in flow communication with the interior of the lifting head in the manner described above for the central lifting head 142. The suction cups 158 of each lateral lifting head 144, 146 are arranged in three parallel rows comprising, respectively, three suction cups, two suction cups and one suction cup. This arrangement provides each lifting head 144, 146 with a generally stepped triangular appearance which is complementary to the stepped sides 166 of the central lifting head 142. The lateral lifting heads 144, 146 are connected to the platform 128 by telescopic tubular connectors 180. This arrangement permits a degree of vertical displacement of the lifting heads 144, 146 between a rest position, shown in Figure 9 of the drawings, in which they lie in a plane which is at a level lower than the plane in which the central lifting head 142 lies and a displaced position in which they lie in the same plane as the central lifting head 142.

In addition, the lateral lifting heads 144, 146 are angularly displaceable about vertical axes through 90°. To this end, as can best be seen in Figures 10 and 13 of the drawings, an electric motor 182 is mounted on the platform 128 and is drivingly connected via an endless chain and sprocket arrangement, generally indicated by reference numeral 184, to the connectors 180.

Two vacuum pumps 186, 188 are mounted on the carriage 120. The vacuum pump 186 is connected in flow communication with the central lifting head 142 by means of a pipe 190. The vacuum pump 188 is connected in flow communication with the lateral lifting heads 144, 146 via pipes 192.

An electric motor 194 is mounted on the carriage 120 and is drivingly connected to four pinion gears 196. Each of the pinion gears 196 drivingly engages a rack 198 mounted to one of the posts 126 to permit vertical displacement of the turntable 122 between a raised position and a lowered position.

Control of the installation is by means of a programmable logic controller (not shown).

In use, with the bricks arranged in the feed zone in the manner described above with reference to Figure 2 of the drawings, the carriage 120 is positioned directly above the bricks with the central lifting head 142 positioned such that the suction cups 158 are in register with the bricks marked B. The lateral lifting heads 144 and 146 are positioned such that their lifting cups are in register with the bricks marked A and C, respectively.

By operating the electric motor 194, the turntable 122 is lowered such that the suction cups contact the bricks and, by virtue of the suction or vacuum drawn by the vacuum pumps 186, 188, adhere thereto. The electric motor 194 is once again energized to displace the carriage 120 upwardly lifting the sets of bricks A, B and C. As the carriage 120 moves upwardly, the lifting heads 144, 146 move into a position in which they lie in a plane below the plane in which the lifting head 142 lies. The electric motor 182 is then energised to displace the lifting heads 144, 146 through 90° so that the lifting heads are arranged in the configuration shown in Figure 1 1 of the drawings.

At the same time, the carriage 120 is displaced along the tracks 1 18 until it is positioned directly above the stacking zone. The electric motor 194 is energised to lower the carriage 120 and when the bricks are in the desired

position, the operation of the vacuum pumps 186, 188 is interrupted to release the bricks and deposit a layer in the stacking zone on top of a base brick layer 48, on the second stacking conveyor 22, as shown in Figure 4, in the configuration depicted in Figure 5, to form a first stack layer 46 on the base layer 48.

The carriage 120 is then returned to the position above the feed zone, as described above, in register with a subsequent set of bricks positioned in the feed zone.

As can be seen in Figure 5, the brick layer 46 has a square plan profile. The removal of the bricks labeled A, B and C from the position adjacent the end stop 50 of the conveyor 20, as depicted in Figure 2, recreates the same pattern of groups of bricks now labelled a, b and c and these groups are simultaneously lifted by the second brick stacker or stacking machine and, in the same way, are placed on a second base brick layer on the second stacking conveyor 22. The rows of bricks 1 - 8 are then again displaced by the first stacking conveyor 20 until they abut the end stop 50. The procedure of picking up the bricks marked A, B and C is repeated. Similarly, the lifting heads 144, 146 are displaced into the positions shown in Figure 1 1 of the drawings. However, while the carriage 120 is being displaced towards the stacking zone, the electric motor 136 is energised so as to displace the platform 128 through 90° before the bricks are deposited in the stacking zone on the previous layer. This procedure is repeated so that each subsequent layer of bricks is arranged at 90° relative to the previous layer of bricks. For each succeeding brick layer, the stacking machines 30, 32 thus rotate all of the groups A, B, C through 90° relative to the first groups A, B, C to form successive layers 52 etc (see Figure 4). This process is repeated to build up a brick stack 53 as depicted in Figure 4. Identical stacks are thus produced at the same time by the stacking machines 30, 32. Once the desired stacks have been produced, typically a fourteen layer stack located on the base layer 48 as depicted in Figure 4, the second stacking conveyor 22 transfers the stacks to a grab-forklift remover (not shown) which lifts the stacks from an end

zone 23 of the second stacking conveyor 22, and transfers the stacks for transport or storage.

As can be seen in Figure 4, each stack has a smooth plan profile and the base layer 48 projects outwardly to produce an overlapping portion which can readily be gripped by the grab-forklift remover.

In another embodiment of the invention, the end stop 50 may have the shape shown in Figure 3. In this embodiment of the invention, the rows 1 and 8 will first be stopped by the stop formations 50.1 and 50.8. Thereafter the rows 2 and 7 will be stopped by the stop formations 50.2 and 50.7. The rows 3 and 6 will then be stopped by the stop formations 50.3 and 50.6, and the middle rows 4 and 5 will simultaneously and lastly be stopped by the stop formations 50.4 and 50.5. In this embodiment of the invention, the groups of bricks marked A, B and C will again be lifted separately by the stacking machine 32, the groups A and C will be rotated through 90° and placed on top of a base brick layer to again produce the arrangement depicted in Figure 5 so that the same procedure can be followed to produce the stack shown in Figure 4.

In this embodiment of the invention, although the bricks marked A, B and D could be lifted, it is preferable that the bricks marked A, B and C be lifted and that the group of five bricks marked D be left in place thereby creating the profile shown in Figure 2.

In another embodiment of the invention as shown in Figure 20, the first stacking conveyor 20 is not provided with the end stop 50 so that the bricks on the conveyor 20 are simply aligned in side-by-side rows as for the rows 4 and

5 of Figure 2. In this embodiment of the invention, the stacking machine 32 lifts eight-by-four groups of bricks and places them on a base brick layer 48 as shown in Figure 7. Successive eight-by-four layers 54 are then placed on top of the earlier layers with each layer rotated by 90° with respect to the layer below it to produce a stack 55 having the shape depicted in Figure 7. Figure

6 shows two of the layers 54 of the stack of Figure 7 one on top of the other with the lower layer shown in broken line. Although the bricks of one layer 54

are staggered with respect to the bricks of the next layer 54 because of the rotation of the layers with respect to one another through 90° the stack produced has perpendicular lines of weakness, indicated by the arrow 56, in which there is no overlap. Such a stack is less stable than the stack depicted in Figure 4.

Referring now to Figures 21 to 33, reference numeral 200 generally indicates a brick stacking installation according to another embodiment of the invention.

Parts of the installation 200 that are the same as, or similar to, those of the installation 10, are indicated with the same reference numerals.

Thus, the installation 200 includes a transfer conveyor 14, a mechanical destacker 16, a brick tilt conveyor 18, a first stacking conveyor 20, a second stacking conveyor 22, a first base brick conveyor 24 and a brick stacker 30, as hereinbefore described with reference to the installation 10. However, the installation 200 also includes, instead of the base brick destacker 28, a base brick lifter or packer unit, generally indicated by reference number 210.

The base brick packer unit 210 includes a hoist assembly, generally indicated by reference numeral 212. The hoist assembly includes a vertically upright post 214 mounted to the floor, with a horizontally extending arm 216 pivotally attached, at 218, to the post 214. The hoist assembly 212 also includes a suction assembly, generally indicated by reference numeral 220. The suction assembly 220 includes a suction header, generally indicated by reference numeral 222. The suction header 222 includes a first base plate 224 as well as a second base plate 226 spaced from the base plate 224 so that a cavity is defined between the base plates. The base plates 224, 226 are substantially rectangular in plan view. A relatively long first side or stop plate 228 extends along one pair of edges of the base plates 224, 226, while a shorter second side or stop plate 230 extends along another pair of edges thereof, as indicated most clearly in Figure 27. Internal divisions 232 divide the cavity defined between the base plates 224, 226, into a first large L-shaped compartment, generally indicated by reference numeral 234, as well as into

two smaller rectangular compartments generally indicated by reference numerals 236 and 238 respectively. A hollow connecting piece 240 is provided for each of the compartments, with each connecting piece 240 being mounted to the base plate 224 and with the interior of the connecting piece 240 being in communication with its respective compartment.

The hoist assembly 212 includes a vacuum pump 242 which is mounted to the post 214. The vacuum pump 242 is connected to a rigid suction pipe 244 by means of a flexible pipe 246. A further flexible pipe 248 connects the end of the rigid pipe 244 to a suction pipe assembly or manifold 250. The suction pipe assembly 250 includes three suction pipes 252, one of which is connected to each connector 240 by means of a vacuum valve 254. The vacuum pipe assembly or manifold 250 includes a fourth vacuum release pipe 256 fitted with a vacuum release valve 258 and a strainer 260. The manifold 250, and the suction assembly 220, are suspended from a pulley/hoist arrangement 262, which runs along the arm 216. Thus, by means of the arrangement 262, the height of the manifold 250 / suction assembly 220, as well as their position relative to the post 214, can be adjusted.

The suction assembly 220 includes an operator control arm 264, mounted to the header 222.

The suction assembly 220 also includes a brick pusher assembly, generally indicated by reference numeral 266. The brick pusher assembly 266 includes a motor/cam combination 268 mounted to the top of the base plate 224 as well as brick pushing arms 270 pivotally mounted to the base plate 224 in proximity to the pair of free edges of the base plates 224, 226 that is remote from the plate 228. The arms 270 are connected to the cam of the electric motor/cam combination 268 by means of rods 272. On actuation of the assembly 268, the arms 270 are pivoted from an upper position as indicated most clearly in Figure 25, to a lower position in which a pusher plate 274 attached to the free ends of the arms 270 moves in below the base plates 224, 226, thereby to push bricks over which the assembly 220 is located, into contact with one another.

The base plate 226 is provided with a plurality of sets of openings 276. By means of outermost smaller openings of each set of openings 276, a suction cup (not shown) is mounted to the plate, with the suction head being in communication with the compartments 234, 236 and 238 via the larger of the openings 276 in each set. The suction cups are similar to the suction cups 158 hereinbefore described with reference to the installation 10 and illustrated in, for example, Figures 18 and 19. Thirty-six of the suction heads are provided, arranged in four rows, each row containing nine suction heads. The rows extend parallel to the side plate 230, as seen most clearly in Figure 26 and Figure 28. The side plate 230 extends from the side plate 228 alongside one of the rows of suction cups; however, the side plate 230 stops short of the ninth suction cup (counting from the side plate 228).

The destacker 60 of the installation 200 is similar to the destacker 16 as hereinbefore described in respect of the installation 10. However, the destacker 16 of the installation 200, also includes pallet removal means, generally indicated by reference numeral 300.

The pallet removal means 300 includes a rectangular hollow framework 302 mounted to the displacement member 88. The framework 302 includes a connection (not shown) by means of which it can be connected to suction generating means (not shown).

Four connecting pipes 304, the interiors of which are in communication with the interior of the framework 302, depend from the framework 302. Each connector 304 fits slidingly within a further tubular connector 306 with bias means in the form of springs (not shown) being associated with each of the pair of connectors 304, 306. The bias means urges the framework 302 upwardly away from the displacement member 88. To the lower end of each of the connectors 306 is mounted a suction cup 308, which is similar to the suction cups 158 hereinbefore described with reference to Figures 18 and 19.

To the support structure 70 of the destacker 16 is mounted an electric motor 310 provided with an eccentric cam 312. The eccentric cam 312 is in turn mounted to an arrangement 314 by means of which, as the cam 312 rotates, the framework 302 can be urged downwardly, against the bias of the springs; however, on the cam rotating further, the arrangement 314 is then moved out of contact with the framework 302, allowing it to be urged upwardly again by the springs.

In use, the various components of the installation 200 function in substantially identical fashion to the corresponding components of the installation 10. However, in the case of the destacker 16 of the installation 200, once the bricks have been pushed off a pallet stacked within the stacker onto the conveyor 18, with the pallet then being empty, the pallet is removed by the electric motor 310 / cam 312 combination depressing, via the arrangement 314, the framework 302 against the bias of the springs until the suction cups 308 are in contact with the pallet. The suction generating means is then operated so that a suction or vacuum is drawn within the hollow framework 302. By means of the suction that is thereby created in the suction cups 308, the pallet adheres to the suction cups 308. On the cam 312 rotating further, the arrangement 314 is drawn clear of the framework 302. This permits the framework 302 to lift relative to the displacement member 88. The empty pallet will thus be lifted clear of the stack contained within the destacker and, on the displacement member 88 moving rearwardly, the empty pallet is simultaneously withdrawn with it. On the displacement member reaching its fully retracted position, the pressure within the framework 302 and hence within the suction cup 308, can be restored, thereby permitting the empty pallet to be released. The empty pallet can pass into a chute (not shown) from where it can be retrieved for re-use.

In the installation 200, to form the bricks into the base layer 48, a pallet/brick stack 36 located on the conveyor 24 contains, on the uppermost pallet 34 thereof, fifty-four bricks 33, arranged in six rows of 9 bricks each. The bricks are typically spaced about 10mm apart, end-to-end and side-to-side. The operator of the hoist assembly 212 positions the suction assembly 220 such

that its plate 228 extends alongside four rows of bricks 33 as indicated most clearly by general arrow 280 in Figure 28. The suction header 222 is lowered until the suction cups 158 are in contact with the uppermost side faces of the bricks 33. The operator then actuates the brick pusher arms 270 so that the head or plate 274 engages the outermost bricks in each of the rows, with the bricks thus being pushed against each other by means of the arms 270 and plate 274. The operator then actuates the vacuum pump 242 with the resultant suction that is created causing the bricks to adhere to the suction cups, lifts the assembly with the bricks attached thereto, rotates the arm 216, and deposits the bricks against a guide rail 282 of the conveyor 222, as indicated most clearly in Figure 29. The suction within the compartments 234, 236 and 238 is then released, so that all the bricks are deposited onto the conveyor 22.

The operator then again manipulates the arm 216 and the assembly 220, so that the assembly 220 is then repositioned over the remaining two rows of nine bricks each on the particular pallet that is uppermost on the conveyor 24 as indicated most clearly by reference numeral 284 in Figure 28. By creating suction in the compartments 236 and 238, sixteen bricks are then lifted, with two bricks, identified by reference numeral 286, remaining on the conveyor 24. These bricks can be used to replace any broken bricks that are evident to the operator. The bricks that are lifted in this step, are then placed on the conveyor 22 in the position indicated in Figure 30, after the arms 270 and plates 274 have again be actuated to press the bricks against each other so that their side faces abut.

When the header assembly is in the position indicated in Figure 30, pressure is restored in the compartment 236, thereby depositing the bricks associated with that compartment onto the conveyor 22; however, the vacuum is maintained in the compartment 238. The assembly 220 is then lifted again, so that the bricks as indicated in Figure 31 remain on the conveyor 22. The bricks still attached to the header assembly 222 by means of the suction cups associated with the compartment 238, are then deposited in the position as indicated in Figure 32, thereby forming the base brick layer 48.

The Inventor believes that a brick stacking installation in accordance with the invention will be capable of forming stable brick stacks rapidly and in a cost effective manner.

Further, the Inventor believes that by using a brick stacker in accordance with the invention in a sequence which is the reverse of that described above, the stacker can be used to un-stack bricks from a brick stack and lay them in a generally horizontal plane for paving.