WO2005059272A1

WO2005059272A1 - Apparatus for mechanical bricklaying

Info

Publication number: WO2005059272A1
Application number: PCT/AU2004/001792
Authority: WO
Inventors: Rodney Munro Linklater
Original assignee: Rodney Munro Linklater
Priority date: 2003-12-18
Filing date: 2004-12-20
Publication date: 2005-06-30

Abstract

An aligning mechanism (50) for use in the construction of a brick wall, said mechanism including ferst and second spaced apart brick engagement formations (52,54). The engagement formations define a gap therebetween to accommodate the width of a brick. Biasing means (70) urge at least one of the engagement formations towards the other, whereby as the mechanism moves along a course of bricks, the engagement formations urge the bricks into relative alignment. The aligning mechanism may be used in conjunction with a mortar laying machine or a brick placing apparatus to construct brick walls and related structures.

Description

APPARATUS FOR MECHANICAL BRICKLAYING

FIELD OF THE INVENTION This invention relates to an improved bricklaying apparatus.

BACKGROUND OF THE INVENTION The invention has been developed primarily for use in constructing brick walls, and will be described predominantly with reference to this application. It will be appreciated, however, that the invention is not limited to this particular field of use, being also applicable to any structure formed by laying a course of bricks over another in a predetermined pattern. Any discussion of the prior art that has been included in this specification is intended solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any such art formed part of the prior art base or the common general knowledge in the relevant field at the priority date. Brick walls are currently generally laid by hand in the well known traditional method. A quantity of premixed mortar is trowelled on a previously laid course of bricks, and an end of each brick is buttered with mortar and positioned on the previous course adjacent the last laid brick. Despite the apparent simplicity of the operation, bricklaying is in fact a highly skilled operation and bricklayers are generally highly skilled tradesmen who are paid commensurately with their skill. Thus the erection of brick walls by traditional methods is not only laborious and time consuming, but is also expensive. Australian Patent No 645521 discloses a machine for depositing dry mortar on top of a previously laid brick course and which also applies a mortar setting liquid, typically water, to the dry mortar in specific amounts by way of a fine spray. The liquid and mix convert in situ into a moist but still firm bed of mortar ready to receive and support successive bricks of the next course. Cavity brick walls are formed from two spaced apart brick courses. The spacing or cavity is to prevent transmission of moisture from the outside to the inside of the building. A good quality cavity brick wall for a building such as a house, will have mortar joints that are continuously smooth and tidy in appearance on its outer facing side which forms the outside of the building. Also the cavity will contain a minimum amount of mortar, so as to minimise the extent of migration of moisture across the cavity. The present invention is directed to improvements to the apparatus disclosed and claimed in Australian Patent No 645521, the entire contents of which are incorporated herein by reference, which improvements make the apparatus particularly suited to making cavity brick walls. It is an object of the present invention to overcome or ameliorate limitations or disadvantages of the prior art, or at least to provide a useful alternative.

SUMMARY OF THE INVENTION Accordingly, in a first aspect, the invention provides, an aligning mechanism for use in the construction of a brick wall, said mechanism including first and second spaced apart brick engagement formations defining a gap therebetween to accommodate the width of a brick, and biasing means for biasing at least one of the engagement formations towards the other, whereby as the mechanism moves along a course of bricks, the engagement formations urge the bricks into relative alignment. Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. The term "relative alignment" refers to a predetermined geometric relationship between the individual bricks in a course of bricks. Generally it will apply to the case where the exposed faces of the bricks in a course are substantially co-planar. However, is not limited to such an arrangement and may encompass offset, staggered, stepped, curved or any other form of non-random alignment. Preferably, each formation includes a corresponding set of rollers mounted for rotation about respective generally vertical axes as they engage corresponding faces of the bricks. Preferably, the biasing means includes a pair of pneumatic or hydraulic cylinders, each connected to a respective independent linkage, in turn connected to a respective set of rollers. Preferably, the first set of rollers is fixed and the second set of rollers urges the bricks into contact with the first set so that so that the first set defines an edge position for the course. Preferably, the mechanism is mounted on a wheeled, self propelled carriage for supporting and transporting the mechanism along a predetermined path adjacent the course of bricks. Preferably, the carriage includes an arm for supporting the aligning mechanism. The arm is preferably configured to be raised and lowered. Preferably, the arm includes a frame for supporting the aligning mechanism and the frame is preferably configured to move along the arm. According to a second aspect, the invention provides a mortar laying machine for use in constructing a brick wall, said machine including: a carriage; a mortar laying head for distributing mortar onto a course of bricks; and an aligning mechanism in accordance with the first aspect of invention as previously defined, for aligning the course, wherein the head and the aligning mechanism are mounted to the carriage. Preferably, the aligning mechanism aligns the bricks in the course before the head distributes mortar onto the course. Preferably, the mechanism is configured to dampen movement of the machine against the course. h alternative embodiments, the mortar laying machine includes twin- mounted mortar laying heads and twin mounted aligning apparatus for laying mortar on a pair of spaced brick courses simultaneously, in the formation of a double brick cavity wall. According to a third aspect, the invention provides a brick placing machine for use in constructing a brick wall, said machine including: a carriage: a brick placing apparatus for placing bricks to form a course of bricks; and an aligning mechanism in accordance with the first aspect of the invention as previously defined for aligning the course, wherein said apparatus and mechanism are mounted to the carriage. Preferably, the brick placing machine places the bricks in the course before the aligning mechanism aligns the bricks. Preferably, the mortar laying machine is adapted to lay down a bed of fresh mortar and the brick placing machine is adapted to position a course of bricks on the mortar, whereby a base is formed for the next course of bricks, hi this way, the brick placing machine and mortar laying machine are preferably used in combination to progressively form a wall, course by course. According to another aspect, the invention provides a mortar laying head for a mortar laying machine for distributing mortar onto a course of bricks as the head moves along and above said course, said head including: an outlet box for distributing dry mortar mix onto the course and within each perpend joint between the bricks of the course; and a spray for wetting the dry mortar mix. Preferably the head includes a spray for pre-wetting the bricks in the course at predetermined areas before the mortar is distributed.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a schematic front view of an machine embodying the present invention; Fig. 2 is a schematic view showing an aligning mechanism in accordance with the invention; Fig. 3 is a side view of the mechanism shown in Figure 2; Fig. 4 is a schematic plan view of the machine shown in Figure 1 ; Fig. 4A is a schematic plan view of an machine according to the invention employing twin mortar heads; Fig. 5 is a schematic side view of part of the machine illustrating the operation of spraying of water onto bricks and dry mortar; Fig. 6 is an end view of the operation shown in Figure 5 omitting an outlet box, for reasons of clarity; Fig. 7 is a schematic side view of part of the apparatus illustrating the discharge of mortar from a hopper onto a course of bricks, omitting the sprays for clarity; and Fig. 8 is a cross-section on lines VIII-NIII of Figure 7; Fig. 9 is a cross-section on lines IX-IX of Figure 7; Fig. 10 is a schematic of bricks showing pre- wet areas; Fig. 11 A is a side view from the cavity side of the outlet box; Fig. 1 IB is a rear view of the outlet box; and Fig 11C is a side view of the outlet box taken from the face side.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The drawings show a machine 10 for forming mortar on the upper surface and the perpend joint of a brick course. The machine is to be used in conjunction with a brick placing apparatus, which may be part of the same machine, but will typically be a separate machine. In general, with regard to the forming of the mortar, the machine 10 works generally in the same way as the invention described in the earlier Australian Patent No 645521, the entire contents of which are incorporated herein by reference, but with some refinements and improvements. Turning to Fig. 1, the machine 10 includes an upright carriage 15 running on wheels 14. A motor and drive system schematically illustrated at 16 is provided to drive the wheels and move the carriage 15. The carriage carries a computer control means, symbolically illustrated at 19, and other components described below. The carriage is driven along a concrete slab on which a course of brickwork is to be laid. The carriage shown is guided on a predetermined path by a laser guide beam 17 laid adjacent the path. However, in alternate embodiments, the carriage may be guided by any appropriate means including one or more of the following; guide rails, a preprogrammed path, guide wires or markers, a laser guidance system, inertial control, GPS control, a local positioning system based on spatial orientation from one or more fixed markers, and the like. The carriage 15 extends upwardly and generally perpendicularly from the wheels 14 along a vertical axis. A support arm 18 extends away from the carriage in an orientation generally normal to the vertical axis of the carriage. A motor 13 is provided for moving the arm up and down with respect to the carriage. A part-conical hopper 22, is carried on a frame 23, located at the remote end of the support arm 18. The hopper feeds a delivery tube 24 which in turn connects to an outlet box 26 described in more detail below. The outlet box 26 has an open bottom spaced above the bricks 28a of a course of bricks 28 by a distance corresponding to the intended depth of a layer of dry mortar mix to be deposited thereon. This distance is ideally between 6 mm to around 10 mm, and most typically around 8 mm. The bottom opening of the outlet 26 is slightly narrower than the width of the brick 28a so as to prevent mortar from spilling over the sides of the brick course and accumulating in the wall cavity. Hereinafter, these components are referred to collectively as the "mortar head" 29. A mechanical feed, which is not shown in the drawings, feeds dry mortar to the hopper 22. The arm 18 may be raised on the carriage to account for the height of the brick layer being mortared, using the motor 13. Typically the height of the arm will be adjusted so that the outlet box is from 6 to

10 mm above the course of bricks onto which a layer of mortar is to be formed. A motor 20 is located at one end of the arm 18 for moving the arm in and out along a horizontal axis, thereby selectively to displace the mortar head 29 towards and away from the carriage 15. One or more accelerometers 21 may be located on the carriage and/or the arm, to feed movement information to the control means 19. In particular, in the event that the upper part of the carriage sways, the controller causes the motor 20 to move the arm and mortar head 29, so as to compensate and to ensure that the mortar head 29 remains a conectly positioned over the course of bricks 28. The wheels also include selectively operable clamps or brakes (not shown), adapted to be actuated by the controller when the carriage is stationary, so as to anchor the structure securely and enhance its rigidity when placing the mortar. As can be seen in Fig. 4, the arm 18 carries mortar head 29 on frame 23. The mortar head 29 can be moved along the length of the frame 23 by means of motor 25. It will be appreciated that this movement of the head is necessary for forming corners. Fig. 4 A shows a twin headed version of the machine 10 including two mortar heads 29 and 29a mounted on frames 23 and 23a respectively. Again, each head is moveable along frame 23 and 23a so that the machine can form corners. In addition, because the mortar heads are "sided", two mortar heads are required to avoid dispensing mortar into the cavity, one mortar head for laying the outer brick course and one for the inner brick course. Figs. 2 and 3 illustrate an aligning mechanism 50 of the machine 10 in more detail. Note that for clarity, the mechanism 50 has been omitted from Figure 1. The aligning mechanism comprises two opposed sets 52 and 54 of four "in line" rollers or wheels 56 mounted on generally vertical axles depending from two horizontally oriented bars 58, 60 respectively, such that each set of rollers may turn about a corresponding generally vertical axis. The axes, Vi and V₂, about which the rollers turn, may be vertical, upwardly convergent, or upwardly divergent as shown in Figure 2. The rollers may be made of any suitable low friction material such as acetyl or polyurethane. The bars 58 and 60 are located at the lower ends of two rods 60 and 62 respectively, which are supported for rotation about respective pivots 64 and 66. . Two pneumatic cylinders 68 and 70 and associated bellows type linkages 72 tend to pivot the rods 60 and 62 about their respective pivots and thereby tend to move the rollers 52 and 54 towards each other as the air in the cylinders 68 and 70 expands. This expands the linkages 72 and rotates the rods 60 and 62 about their respective pivots 64 and 66, thereby applying a biasing force to any bricks contacting the associated rollers. Conversely, contraction of the cylinders 68 and 70 causes contraction in the length of the link mechanism. While air cylinders have been used in this embodiment, because they provide instant and variable control over the biasing force, it is conceivable that many other types of biasing arrangements may be used, including but not limited to hydraulic cylinders, mechanical actuators, springs, electromagnetic solenoids, and the like. The left and right side linkages are independent so that the position of one set of rollers 54 can be changed without affecting the position of the other set 52. This allows either set of rollers to be fixed to provide a stop or guide means to govern where the outer edge of the bricks in the brick course will be located. For instance, a fixed stop means 71 prevents the rollers 54 from moving towards the brickwork beyond a predetermined limit. The other set of rollers 52 is biased inwardly by the pneumatic cylinder 68. In this way, the inside or cavity side face of each brick is urged by the "moveable" set of rollers 52, towards the "fixed" set of rollers 54 which define the location for the outside face of the brick course, thereby progressively straightening each course in the wall. As will be appreciated, the relative displacement between the "fixed" rollers 54 and the apparatus is critically important to the final position of the wall. Referring to Fig.2, in order to prevent the bricks being pushed too far by rollers 52, the rollers 54, in addition to being prevented from inward movement by the stop means, may be locked in position. This effectively ensures that the rollers 54 are not deflected outwardly under normal operating conditions. Locking of the rollers 54 may be accomplished by any number of means including another stop means. However, because it is preferable that the rollers 54 are not permanently fixed, so that they can be moved out of the way when aligning the machine during initial setting up phases, they are effectively locked by running disproportionate pressures in the cylinders 68 and 70. That is, by maintaining a pressure in cylinder 70 beyond that in cylinder 68. Turning now to describe the mortar laying apparatus in more detail, figures 5 and 6 show the mortar head. Spray heads, numbered 1 to 8 can be seen positioned around the outlet 26. These spray heads both pre-wet the bricks and moisten the mortar, including both the mortar that is layered on the tops of the bricks and also the mortar which is inserted between the vertical ends of the bricks to form the respective perpend joints. While the operation of the sprays is largely similar to that described in Australian Patent No 645521, there are some differences. Referring to figures 5 and 6, sprays 1, 2 and 3 pre-wet the brick before the dry mortar is applied. Pre-wetting the bricks provides an effective means of controlling the flow of mortar. The dry mortar is particularly hydrophilic and will draw fluid from the wet brick. In addition, the flow properties of the mortar alter rapidly with increasing dampness. The dry mortar will readily flow whereas the damp or wet mortar becomes "sticky" and less likely to flow. By exploiting these properties of the mortar, and pre-wetting the bricks in carefully selected areas, the distribution of mortar can be controlled. Careful control of the mortar flow is important in order to produce a high degree of consistency of finish, minimize waste, and avoid mortar falling into the wall cavity. The spray nozzle 1, which can be seen in figures 5 and 6, is centrally mounted in front of the outlet box 26 and controlled to operate periodically, more or less as the peφend joint passes beneath. That is, it is designed only to wet the ends of bricks B_\ and B within the peφend joint. The spray may be a conical or flat spray so as to wet a central vertical strip, slightly on the face side and about 5-6mm in width on the end of the brick. As discussed above, this distribution of spray has been found to help control the flow of dry mortar within the joint. The orifice opening in the nozzle is around 0.66mm in diameter and operates at a water pressure of around 600kPa. Sprays 2 and 3 (see figure 6) are edge sprays. These sprays pre-wet the longitudinal edges of the bricks and the vertical edges of the peφend joints, particularly on the face side which helps prevent the flow of dry mortar mix over those edges. They are flat sprays, spraying in a flat arc of 90 degrees, aligned longitudinally and have an equivalent orifice diameter of 0.66 mm. They operate at a water pressure of 200 to 500 kPa, and typically around 400 kPa. These sprays typically operate continuously. Figure 10 shows bricks B_\ and B as if they had been pre-wet, but before mortar has been applied. The shaded zones la, 2a and 3a represent the areas pre-wet by sprays 1, 2 and 3 respectively while the hatched sides are the cavity sides of the bricks. Preferably, the spray nozzles 1, 2 and 3 are all on the same transverse line. Sprays 4 and 5 are peφend joint sprays which wet the dry mortar mix which forms the peφend joint between two adjacent bricks Bl and B2 in a course. These spray heads are configured for reciprocating motion. The controller 19 controls the timing and speed of the joint sprays to accord with the speed of travel of the mortar head so that the joint sprays remain substantially stationary at each peφend joint for a predetermined period or with enough time to complete a cycle. The sprays 4 and 5 are mounted on rods 4a and 5 a respectively. This arrangement enables translational movement of the spray heads up the peφend joint as mortar is deposited into the joint, and subsequent downwards movement after spraying of each peφend joint is completed, as is described in Australian Patent No 645521. Each spray defines two rows of five 0.18 mm diameter jets of water spaced 3-5 mm apart in both directions (i.e. each spray defines 10 outlets in total). The water pressure applied to the jets is around 600 -700 kPa. In use, these sprays operate as the mortar head 29 passes over the gap between two bricks Bl and B2 to form the peφend joint. The falling dry mix flows down into the peφend joint and then rolls sideways to the outside edges of the joint. The sprays 2 and 3 penetrate the oncoming dry-mix to a depth of around 10-15 mm and, together with the dry-mix that has stuck to the pre-wetted edges of the peφend joint, produce a congealed mixture which ultimately forms a bonded mortar joint between adjacent bricks. The rise rate of the jet sprays is timed to match the natural rise rate of the filling dry-mix. It will be appreciated that the precise number, size, shape and water pressure used in all the sprays may be varied or optimised to suit particular brick compositions, mortar formulations, machine speeds and other operating conditions without departing from the scope of the invention. For instance, the peφend joint sprays may include more or less than the 10 holes disclosed here, as appropriate. Sprays 6, 7 and 8 are course wetting jets and are arranged above the upper surfaces of the bricks B, these are flat sprays having orifices with equivalent diameters of 2 mm and spraying in arcs of 80 degrees. They operate at a water pressure of around 150 kPa. The operation of these sprays is much less critical than the other sprays, as they are simply required to deliver sufficient water to wet the dry mortar mix dispensed onto the tops of the bricks B. These sprays typically switch off as they pass over the peφend joints. In some embodiments, one or more additional spays may be used to further control and wet the bricks or mortar. For instance, a spray may be used to spray dry mortar away from the edges of the brick adjacent the cavity to prevent it falling into the cavity. It is even possible that one or more sprays be added or replace fluid sprays with blowers which direct compressed air rather than fluid. Figures 6 and 7 illustrate the outlet box 26 in more detail. The outlet box is positioned at the base of the mortar dispensing system which includes the hopper 22, the tube 24 and the outlet box 26. The tube 24 includes a 4 mm diameter outlet for injecting compressed air at a pressure of around 0.3 kPa into the mortar mix. The compressed air aids in fluidizing the dry mortar mix to improve its flow characteristics. More compressed air outlets may be placed within the feed line to the outlet box to further aid in flow of the mortar, as required. For instance, the outlet box itself includes two 4 mm diameter outlets 80 and 82 located at the back and front respectively. The front 84 of the outlet box is a continuation of the tube 22. The rear 86 of the box extends away from the tube and the outlet box 26 is enlarged relative to the cross-section of the tube 24. The box is about 2/3 the length of a brick and about half the width. The box has no floor, being entirely open. The side wall 94 of the main body of the outlet box, as shown in Figure 9, includes an upper upright portion 94a and a lower sloping portion 94b which, in use, tends to direct dry mortar away from the cavity side 96. The other side wall 95 is planar. The rear end of the outlet box is rectangular and acts as a plough to level the mortar. As seen in figures 7 and 11 A, there is a cut-out 88 in one side wall 94 of the box adjacent the base and rear 86 of the box. The cut-out portion has the effect in use of delivering dry mortar to the edge of the brick B which forms the visible outer face 90 of the cavity wall, which results in a raised pile of mortar 92 shown in Figure 8. A sliding door 88a actuated by air cylinder 88b closes the cut-out portion as it passes over the peφend joint. This limits the amount of mortar flowing into the joint on the cavity side and therefore reduces spillage into the cavity. In addition, as seen in Fig. 11C, a smaller cut-out 89 is located in side wall 95 opposite the larger cut-out 88. This smaller cut-out also includes a sliding door 89a. The door 89a is also actuated by an air cylinder which is not shown in the drawings.

However, in contrast to door 88a on the cavity side, the door 89a on the face side is programmed to open only as the cut out 89 passes over the joint. This allows more mortar to enter to joint on the face side. It is apparent that the door 88 is configured for horizontal sliding whereas the door 89 is configured for vertical movement. This, along with the exact size and shape of the cut-out and door, as well as the timing of the opening, may be varied depending on the flow characteristics of the mortar. In use, the machine 10 travels along a pre-placed layer of bricks at a set speed in the direction D as shown in Fig. 7. The rollers 52 and 54 push against the bricks and straighten any which are out of alignment, with the intended course being set by the laser guide 17. As shown in Fig. 5, the mortar head applies and moistens the dry mortar after the bricks have been straightened. Dry mortar mix having a composition as described in Australian Patent No 645521 is continuously fed by gravity from the hopper 22 through the tube and to the outlet box. The sprays operate to wet the mortar as and when it lands on the tops of the bricks and in the peφend joints in the manner described in Australian Patent No 645521. The result is a continuous even build up of wet mortar on the outer (face) side of the bricks which can be smoothed and finished either mechanically or by hand. The configuration of the outlet box and the pre-wetting of the bricks are designed to direct the mortar toward the face side rather than the cavity side of the joint. A well- formed joint will have the cavity side half of the joint substantially free of mortar with good filling on the face side. The upper surface of the bricks will be covered with an even level layer of mortar, and on the cavity side, no mortar dry or wet should fall off. It is envisaged that, in practice, a mortar laying machine 10 such as that described above and a brick placing apparatus, following the machine 10, will travel around the inside of a structure being built, building up successive courses of brickwork, with each course of bricks being placed on top of a bed of mortar soon after the mortar is laid. The brick-placing machine will also be equipped with an aligning mechanism of the type described to ensure that the bricks are placed accurately. It will be appreciated that in order to provide accurate operation of the machine 10, it is highly preferable that it is well stabilized or at least that any forces on the mortar head can be compensated for. Moreover, stabilization becomes increasingly difficult as the wall is constructed course by course and its height increases, because the moment arm to the main supports, being the carriage wheels 14, increases. Accordingly, as well as straightening the bricks, the aligning mechanism also functions to maintain alignment between the mortar laying apparatus and the intended course work line. In this way, the aligning mechanism operates as a vibration damper or auxiliary support for the entire machine 10 by exerting a damping force through the aligning means onto the wall. The same is also true for the brick placing apparatus. The mass of the bricks and the high viscosity of the wet mortar provide a support to transmit these damping forces. The control system monitors the position of the rollers and mortar heads and adjusts the air pressure in the cylinders 68 and 70 of the aligning mechanism and/or moves the entire mortar head 29 by motors 20 and 25 to compensate. Should a perceptible displacement occur, the locating rollers will quickly be restored to their correct position by the control system. To this end, the clamping pressure of the rollers should be just sufficient to straighten the bricks resting on the fresh mortar. The clamping force of the rollers is carefully controlled and is preferably about 3Kg force but will ultimately depend on the green strength of the mortar. Alternatively, separate mechanisms for brick straightening and damping may be used. For instance, a dedicated brick-straightening device could be employed to precede the machine 10. This would free rollers, 52 and 54 in machine 10, to function exclusively as a vibration damper to aid in preventing excessive movement of the mortar-laying device or the brick placing device. Further, in the case where there is more than one course of bricks laid, rollers 52 and 54 may engage a lower course of bricks. This would allow a greater amount of force to be transmitted to the brick course for damping. Alternatively, the machine may include one pair of rollers to straighten the bricks and another longer pair to provide damping control. Thus the pressure exerted by the dampening device would be over a larger area or at least be applied to more bricks. The invention is intended to encompass aligning devices that may be used in conjunction with mechanised brick placing or mortar laying equipment to provide vibration damping. Although the embodiment described provides only a single mortar laying head, it is envisaged that for forming cavity walls a single apparatus could provide two mortar laying heads side by side, or staggered side by side mortar laying heads, one for the inside brick course and one for the exterior brick course, for simultaneous laying of both courses. Alternatively the inside and outside courses could simply be laid sequentially by two different machines 10, or a single machine 10. In a further variant a single machine could lay bricks and mortar for both courses simultaneously. It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. An aligning mechanism for use in the construction of a brick wall, said mechanism including first and second spaced apart brick engagement formations defining a gap therebetween to accommodate the width of a brick and biasing means for biasing at least one of the formations towards the other, whereby as the mechanism moves along a course of bricks, the engagement formations urge the bricks into relative alignment.

2. A mechanism according to claim 1 wherein the formations include rollers mounted for rotation about generally vertical axes as they respectively engage opposite faces of each brick.

3. A mechanism according to claim 1 wherein each formation includes a set of generally linearly aligned rollers, each roller being mounted on a generally vertical axle for rotation about a generally vertical axis, as the rollers in each set respectively engage corresponding faces of the bricks.

4. A mechanism according to any one of the preceding claims wherein the biasing means includes a pneumatic or hydraulic cylinder.

5. A mechanism according to claim 4 wherein each engagement formation is connected to a respective one of said pneumatic cylinders by means of a respective independent linkage.

6. A mechanism according to any one of the preceding claims wherein the first formation is fixed and the second formation urges the bricks into contact with the first formation such that the first formation defines the position of the course.

7. A mechanism according to any one of the preceding claims, mounted on a carriage for supporting and transporting said mechanism along the course.

8. A mechanism according to claim 7 wherein the carriage is adapted to follow a predetermined path adjacent the course.

9. A mechanism according to claim 7 or claim 8 wherein the carriage is mounted on wheels.

10. A mechanism according to any one of claims 7 to 9 wherein the carriage is self-propelled.

11. A mechanism according to any one of claims 7 to 10 wherein the carriage includes an arm extending from the carriage for supporting the aligning mechanism.

12. A mechanism according to claim 11 wherein the arm is configured to be raised and lowered.

13. A mechanism according to claim 11 or 12 wherein the arm includes a frame for mounting the mechanism to the arm and the frame is configured to move along the arm.

14. A mortar laying machine for use in constructing a brick wall, said machine including: a carriage; a mortar laying head for distributing mortar onto a course of bricks; and an aligning mechanism in accordance with any one of claims 1 to 6 for aligning the course, wherein said head and the aligning mechanism are mounted to the carriage.

15. A mortar laying machine in accordance with claim 14, wherein said carriage supports and transports said head and said mechanism along the course.

16. A mortar laying machine in accordance with any one of claims 14 to 15 wherein the carriage is mounted on wheels.

17. A mortar laying machine in accordance with any one of claims 14 to 16 wherein the carriage is self-propelled.

18. A mortar laying machine in accordance with any one of claims 14 to 17 wherein the carriage includes an arm extending from the carriage for supporting the mechanism and the head.

19. A mortar laying machine in accordance with claim 18 wherein the arm is configured to be raised and lowered.

20. A mortar laying machine in accordance with claim 19 wherein the arm includes a frame for mounting the mechanism and the head to the arm and wherein the frame is configured to move along the arm.

21. A mortar laying machine in accordance with any one of claims 14 to 20 wherein the mechanism and the head are configured such that the mechanism aligns the bricks in the course before the head distributes mortar onto the course.

22. A mortar laying machine in accordance with any one of claims 14 to 21 wherein the carriage follows a predetermined path adjacent the course.

23. A mortar laying machine in accordance with claim 22 including control and position sensing systems to maintain correct alignment of the course with respect to the path.

24. A mortar laying machine in accordance with any one of claims 14 to 23 wherein the mechanism is configured to dampen movement of the machine against the course.

25. A mortar laying machine in accordance with any one of claims 14 to 24 including twin-mounted mortar laying heads and twin mounted aligning apparatus for laying mortar on a pair of spaced apart brick courses simultaneously.

26. A brick placing machine for use in constructing a brick wall, said machine including: a carriage: a brick placing apparatus for placing bricks to form a course of bricks; and an aligning mechanism in accordance with any one of claims 1 to 6 for aligning the course, wherein said apparatus and said mechanism are mounted to the carriage.

27. A brick placing machine in accordance with claim 26, wherein said carriage supports and transports said apparatus and mechanism along the course.

28. A brick placing machine in accordance with any one of claims 26 to 27 wherein the carriage is mounted on wheels.

29. A brick placing machine in accordance with any one of claims 26 to 28 wherein the carriage is self-propelled.

30. A brick placing machine in accordance with any one of claims 26 to 29 wherein the carriage includes an arm extending from the carriage for supporting the mechanism and the apparatus.

31. A brick placing machine in accordance with claim 30 wherein the arm is configured to be raised and lowered.

32. A brick placing machine in accordance with claim 31 wherein the arm includes a frame for mounting the mechanism and the apparatus to the arm and the frame is configured to move along the arm.

33. A brick placing machine in accordance with any one of claims 26 to 32 wherein the apparatus and the mechanism are disposed such that the apparatus places the bricks in the course before the mechanism aligns the bricks.

34. A brick placing machine in accordance with any one of claims 26 to 33 wherein the carriage is adapted to follow a predetermined path adjacent the course.

35. A brick placing machine in accordance with claim 23 including control and position sensing systems to maintain correct alignment of the course with respect to the path.

36. A brick placing machine in accordance with any one of claims 26 to 35 wherein the mechanism is configured to dampen movement of the machine against the course.

37. A brick placing machine in accordance with any one of claims 26 to 36 including twin-mounted brick placing apparatus and twin mounted aligning apparatus for laying spaced apart brick courses simultaneously.

38. A brick placing machine in accordance with any one of claims 26 to 37 used in conjunction with a mortar laying machine in accordance with any one of claims 14 to 25.

39. A mortar laying head for a mortar laying machine for distributing mortar onto a course of bricks as the head moves along and above said course, said head including: an outlet box for distributing dry mortar mix onto the course and within each peφend j oint between the bricks of the course; and a spray for wetting the dry mortar mix.

40. A mortar laying head in accordance with claim 39 further including a spray for pre-wetting the bricks in the course before the mortar is distributed.

41. A mortar laying head in accordance with claim 40 wherein the pre-wetting spray pre-wets predetermined areas of the bricks .

42. A mortar laying head in accordance with claim 41 including a pair of pre- wetting sprays configured for pre-wetting an area of the course adjacent each respective top edge.

43. A mortar laying head in accordance with claim 41 or 42 including a centrally mounted pre-wetting spray configured to operate intermittently for pre-wetting an area within each peφend joint.

44. A mortar laying head in accordance with any one of claims 39 to 43 including side mounted jet sprays for wetting the dry mortar mix in the peφend joint.

45. A mortar laying head in accordance any one of claims 39 to 44 wherein the outlet box is connected via a feed tube to a hopper for supplying dry mortar mix.

46. A mortar laying head in accordance with claim 45 wherein compressed air is injected into the hopper, feed tube and outlet box to fluidize the dry mortar.

47. A mortar laying head in accordance with any one of claims 39 to 46 wherein the outlet box includes: front and rear walls; a pair of side walls; and a substantially open bottom from which the mortar is distributed.

48. A mortar laying head in accordance with claim 47 wherein a side wall includes a cut out portion in one of the side walls.

49. A mortar laying head in accordance with claim 48 wherein a door opens and closes the cut out portion depending on the cut-out location with respect to the peφend joint.