FOR USE THEREWITH

Priority Documents

[0001] The present application claims priority from Australian Provisional Application No. 2020901272 titled “BLOCK TRANSFER APPARATUS AND IMPROVED CLAMPING ASSEMBLY FOR USE THEREWITH” and filed on 22 April 2020, the content of which is hereby incorporated by reference in its entirety.

Background of the Invention

[0002] The present invention relates to a block transfer apparatus and improved clamping assembly for use therewith. In one particular example, the block transfer apparatus and clamping assembly is suitable for use by a robotic block laying machine.

Description of the Prior Art

[0003] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

[0004] Autonomous and semi-autonomous industrial robotic equipment is increasingly being used in outside work environments such as on construction sites, building sites, mining sites, and industrial sites. For example, WO 2007/076581 describes an automated brick laying system for constructing a building from a plurality of bricks comprising a robot provided with a brick laying and adhesive applying head, a measuring system, and a controller that provides control data to the robot to lay the bricks at predetermined locations. The measuring system measures in real time the position of the head and produces position data for the controller. The controller produces control data on the basis of a comparison between the position data and a predetermined or pre-programmed position of the head to lay a brick at a predetermined position for the building under construction. The controller can control the robot to construct the building in a course by course manner where the bricks are laid sequentially at their respective predetermined positions and where a complete course of bricks for the entire building is laid prior to laying of the bricks for the next course.

[0005] In one example of a robotic construction robot developed by the applicant there is provided a telescoping articulated boom that is mounted on a truck, and a conveying system that transports bricks along the boom to an end effector known as the layhead, which lays the bricks at predetermined locations. When the brick arrives at the layhead via the boom, it is clamped while adhesive is applied and then it is rotated 180 degrees and presented for pickup by a robot arm that places the brick at a desired location, preferably with sub-mm accuracy. When a brick is laid, it is assumed that the brick is held in a certain pose with respect to the robot arm. In order for the robot arm to place a brick at the desired location, it must pick up the brick in the correct location from the clamp.

[0006] One problem is that the exact location of the brick with respect to the clamp in the layhead is not accurately known. It may be translated or rotated slightly away from an ideal pickup location of the robot arm. A camera-based vision system may be used to determine the exact 6DOF location of the brick in space. However, this is a challenging task, as there are spatial constraints at the layhead to place cameras and sensors (without affecting the required functionality) and processing must be performed quickly (e.g. less than 2 seconds) to ensure rapid bricklaying. Further this task is made more difficult due to the varied range of outdoor conditions the robot is required to operate in - this includes temperatures ranging from 0- 50°C, rain, dust, wind as well as full daylight, twilight and dark night lighting conditions. This places significant demands on the vision system for determining the location of the brick to enable precise placement of the brick.

[0007] There is thus a need to develop an improved system for clamping a brick or block such that its location with respect to the clamp is known without requiring vision-based processing techniques, or to at least provide a useful alternative to existing systems. Summary of the Present Invention

[0008] In one broad form, an aspect of the present invention seeks to provide a block transfer apparatus for transferring a block between an upstream clamp of a block delivery system and a downstream clamp of the block delivery system, the block transfer apparatus including: a) a frame pivotally mounted to a support; and, b) a clamping assembly mounted to the frame and linearly extendable relative thereto, the clamping assembly including a pair of gripper jaws for clamping opposing sides of the block; wherein, the block transfer apparatus is configured to: i) receive a block from the upstream clamp, wherein the block is initially clamped in the gripper jaws in an approximate position; ii) rotate to a drop position whereby the gripper jaws release the block and allow it to self-datum onto first and second orthogonal datum surfaces to thereby register an end and top or bottom face of the block in corresponding first and second orthogonal planes; iii) re-clamp the block after the drop by applying a clamping force to opposing sides of the block so as to register the block against a third datum surface defining a third plane orthogonal to both the first and second planes to thereby datum the position of the block with respect to the clamping assembly; and, iv) present the block clamped in the datumed position for transfer to the downstream clamp.

[0009] In one embodiment, the first datum surface that registers an end of the block is provided as part of the clamping assembly at one of: a) a distal end of the gripper jaws; and, b) a proximal end of the gripper jaws to either the jaw or a jaw support structure.

[0010] In one embodiment, the second datum surface that registers a top or bottom surface of the block is at least one of: a) provided as part of the clamping assembly along an upper lengthwise extending edge of the gripper jaws; and, b) provided as part of the frame in the form of a lengthwise extending bar or plate mounted to the support that is parallel to the gripper jaws.

[0011] In one embodiment, the third datum surface is provided by a first of the two gripper jaws.

[0012] In one embodiment, the first gripper jaw has a pair of spaced apart first gripper pads rigidly attached to an inner surface of the jaw.

[0013] In one embodiment, the first gripper pads extend lengthwise along the first gripper jaw.

[0014] In one embodiment, a second of the two gripper jaws includes a plurality of second gripper pads attached to flexible finger members spaced apart along the length of the jaw that allow the pads to flex laterally and compensate for variations in flatness of the side of the block along its length.

[0015] In one embodiment, an at least one row of second gripper pads of the second gripper jaw is located approximately midway between the pair of spaced apart first gripper pads such that when a clamping force is applied to the block it is urged into planar alignment with the third datum surface.

[0016] In one embodiment, the gripper jaws are configured to accommodate blocks of varying length.

[0017] In one embodiment, the gripper jaws are configured to one of: a) clamp blocks of varying length at different pre-defined positions along the length of the gripper jaws; and, b) clamp blocks of varying length at the same position along the length of the gripper jaws.

[0018] In one embodiment, the drop position coincides with the clamping assembly being rotated to a relative angle to the ground of at least one of: a) between 30 to 60 degrees; b) between 35 to 55 degrees; c) between 40 to 50 degrees; and, d) approximately 45 degrees.

[0019] In one embodiment, the support comprises a distal end of a boom used for transferring blocks therealong.

[0020] In one embodiment, the upstream clamp forms part of a shuttle for delivering a block along the boom.

[0021] In one embodiment, the downstream clamp is an end effector of a robotic block placement arm that is programmed to place blocks during construction of a building structure.

[0022] In one embodiment, the block transfer apparatus includes a distance range sensor for use in determining the proximity between the clamping assembly and the block held by the upstream clamp.

[0023] In another broad form, an aspect of the present invention seeks to provide a block delivery system for delivering blocks for placement during construction of a building structure, the block delivery system including: a) a boom for transferring blocks therealong; b) an upstream clamp forming part of a shuttle that delivers blocks along the boom; c) a downstream clamp associated with an end effector of a robotic block placement arm that is programmed to place blocks during construction of the building structure; and, d) a block transfer apparatus for transferring a block between the upstream clamp and the downstream clamp, the block transfer apparatus including: i) a frame pivotally mounted to a distal end of the boom; and, ii) a clamping assembly mounted to the frame and linearly extendable relative thereto, the clamping assembly including a pair of gripper jaws for clamping opposing sides of the block; wherein, the block transfer apparatus is configured to:

(1) receive a block from the upstream clamp, wherein the block is initially clamped in the gripper jaws in an approximate position; (2) rotate to a drop position whereby the gripper jaws release the block and allow it to self-datum onto first and second orthogonal datum surfaces to thereby register an end and top or bottom face of the block in corresponding first and second orthogonal planes;

(3) re-clamp the block after the drop by applying a clamping force to opposing sides of the block so as to register the block against a third datum surface defining a third plane orthogonal to both the first and second planes to thereby datum the position of the block with respect to the clamping assembly; and,

(4) present the block clamped in the datumed position for transfer to the downstream clamp.

[0024] In another broad form, an aspect of the present invention seeks to provide a clamping assembly for clamping a block, the clamping assembly including a pair of gripper jaws including datum surfaces in first and second orthogonal planes to locate the block relative thereto, the clamping assembly configured to locate an end and top or bottom face of the block in the first and second orthogonal planes and then apply a clamping force to opposing sides of the block so as to locate the block in a third plane orthogonal to both the first and second planes to thereby datum the position of the block with respect to the clamping assembly.

[0025] In one embodiment, the datum surfaces form a V-shaped wedge into which the block is located.

[0026] In one embodiment, each gripper jaw includes at least one first datum surface extending at least partially between top and bottom surfaces of the gripper jaw and towards the opposing gripper jaw for locating an end of the block.

[0027] In one embodiment, the at least one first datum surface is provided by one of: a) a surface integral with each gripper jaw; and, b) a plate element mounted to a surface integral with each gripper jaw. [0028] In one embodiment, each gripper jaw includes at least one second datum surface that is parallel to a top or bottom surface of the gripper jaw and projects towards the opposing gripper jaw for locating the top or bottom surface of the block.

[0029] In one embodiment, the at least one second datum surface is provided by one of: a) the top or bottom surface of each gripper jaw; and, b) plate elements mounted to the top or bottom surfaces of each gripper jaw.

[0030] In one embodiment, the at least one second datum surface is discontinuous.

[0031] In one embodiment, the gripper jaws are configured to accommodate blocks of varying length.

[0032] In one embodiment, the gripper jaws are configured to clamp blocks of varying length at different pre-defmed positions along the length of the gripper jaws.

[0033] In one embodiment, each gripper jaw includes a plurality of first datum surfaces spaced apart along a lengthwise direction thereof.

[0034] In one embodiment, the plurality of spaced apart first datum surfaces are further stepped apart laterally with respect to each gripper jaw so as not to overlap in the lengthwise direction thereof.

[0035] In one embodiment, an end of blocks of varying length are each located on one of the plurality of first datum surfaces of each gripper jaw.

[0036] In one embodiment, a first of the pair of gripper jaws has a plurality of first gripper pads arranged to define the third plane for locating a side face of the block when clamped.

[0037] In one embodiment, a second of the pair of gripper jaws has a plurality of second gripper pads arranged co-linearly in a lengthwise direction thereof such that when a clamping force is applied to the block the plurality of second gripper pads act to urge the block into planar alignment with the third plane defined by the plurality of first gripper pads.

[0038] In one embodiment, the plurality of first gripper pads comprise a pair of spaced apart rows of first gripper pads extending in a lengthwise direction of the first gripper jaw and wherein the second gripper pads are located on the second gripper jaw approximately midway between the spaced apart rows of first gripper pads.

[0039] In one embodiment, the first and second gripper pads are arranged on stepped surfaces of each gripper jaw so that each different length of block clamped by the assembly is contacted by a different plurality of first and second gripper pads.

[0040] In one embodiment, any block clamped by the assembly will be in contact with at least four first gripper pads and at least two second gripper pads when a clamping force is applied.

[0041] In one embodiment, the block is allowed to drop into the wedge under gravity to locate onto the datum surfaces defining the first and second orthogonal planes.

[0042] In one embodiment, the clamping assembly is pivotable and the drop is performed when the gripper jaws have been pivoted to a relative angle to the ground of at least one of: a) between 30 to 60 degrees; b) between 35 to 55 degrees; c) between 40 to 50 degrees; and, d) approximately 45 degrees.

[0043] In one embodiment, the block is: a) initially clamped in the gripper jaws in an approximate position; b) rotated to a drop position whereby the gripper jaws release the block and allow it to drop into the wedge; and, c) re-clamped when the block is located in the wedge so that the block is located in a datumed position.

[0044] In another broad form, an aspect of the present in invention seeks to provide a block transfer apparatus for transferring a block between an upstream clamp of a block delivery system and a downstream clamp of the block delivery system, the block transfer apparatus including: a) a frame pivotally mounted to a support; and, b) a clamping assembly mounted to the frame and linearly extendable relative thereto, the clamping assembly including a pair of gripper jaws including datum surfaces in first and second orthogonal planes to locate the block relative thereto, wherein the clamping assembly is configured to at least: i) receive a block from the upstream clamp, wherein the block is initially clamped in the gripper jaws in an approximate position; ii) rotate to a drop position whereby the gripper jaws release the block and allow it to drop into a V-shaped wedge formed by the datum surfaces to thereby locate an end and top or bottom face of the block in the first and second orthogonal planes; iii) re-clamp the block after the drop by applying a clamping force to opposing sides of the block so as to locate the block in a third plane orthogonal to both the first and second planes to thereby datum the position of the block with respect to the clamping assembly. iv) present the block clamped in the datumed position for transfer to the downstream clamp.

[0045] In one embodiment, the support comprises a distal end of a boom used for transferring blocks therealong.

[0046] In one embodiment, the upstream clamp forms part of a shuttle for delivering a block along the boom.

[0047] In one embodiment, the downstream clamp is an end effector of a robotic block placement arm that is programmed to place blocks during construction of a building structure.

[0048] In one embodiment, the block transfer apparatus includes a distance range sensor for use in determining the proximity between the clamping assembly and the block held by the upstream clamp.

[0049] In yet a further broad form, an aspect of the present invention seeks to provide a block delivery system for delivering blocks for placement during construction of a building structure, the block delivery system including: a) a boom for transferring blocks therealong; b) an upstream clamp forming part of a shuttle that delivers blocks along the boom; c) a downstream clamp associated with an end effector of a robotic block placement arm that is programmed to place blocks during construction of the building structure; and, d) a block transfer apparatus for transferring a block between the upstream clamp and the downstream clamp, the block transfer apparatus including: i) a frame pivotally mounted to a distal end of the boom; and, ii) a clamping assembly mounted to the frame and linearly extendable relative thereto, the clamping assembly including a pair of gripper jaws including datum surfaces in first and second orthogonal planes to locate the block relative thereto, wherein the clamping assembly is configured to at least:

(1) receive a block from the upstream clamp, wherein the block is initially clamped in the gripper jaws in an approximate position;

(2) rotate to a drop position whereby the gripper jaws release the block and allow it to drop into a V-shaped wedge formed by the datum surfaces to thereby locate an end and top or bottom face of the block in the first and second orthogonal planes;

(3) re-clamp the block after the drop by applying a clamping force to opposing sides of the block so as to locate the block in a third plane orthogonal to both the first and second planes to thereby datum the position of the block with respect to the clamping assembly; and,

(4) present the block clamped in the datumed position for transfer to the downstream clamp.

[0050] It will be appreciated that the broad forms of the invention and their respective features can be used in conjunction and/or independently, and reference to separate broad forms is not intended to be limiting.

Brief Description of the Drawings

[0051] Various examples and embodiments of the present invention will now be described with reference to the accompanying drawings, in which: -

[0052] Figure 1A is a perspective view of an example of a clamping assembly;

[0053] Figure IB is a further perspective view of the clamping assembly of Figure 1A; [0054] Figure 1C is a side view of the clamping assembly of Figure 1A;

[0055] Figure ID is atop view of the clamping assembly of Figure 1A;

[0056] Figure 2 is a perspective view of a block transfer apparatus incorporating the clamping assembly of Figures lA to ID;

[0057] Figure 3A is a schematic bottom view of a clamping assembly shown in use clamping a first block type;

[0058] Figure 3B is a schematic top view of the clamping assembly of Figure 3A;

[0059] Figure 3C is a sectional view of the clamping assembly taken through section A-A of Figure 3A;

[0060] Figure 4A is a schematic bottom view of a clamping assembly shown in use clamping a second block type;

[0061] Figure 4B is a schematic top view of the clamping assembly of Figure 4A;

[0062] Figure 4C is a sectional view of the clamping assembly taken through section B-B of Figure 4A;

[0063] Figure 5A is a schematic bottom view of a clamping assembly shown in use clamping a third block type;

[0064] Figure 5B is a schematic top view of the clamping assembly of Figure 5A;

[0065] Figure 5C is a sectional view of the clamping assembly taken through section C-C of Figure 5A;

[0066] Figure 6A is a schematic bottom view of a clamping assembly shown in use clamping a fourth block type;

[0067] Figure 6B is a schematic top view of the clamping assembly of Figure 6A; [0068] Figure 6C is a sectional view of the clamping assembly taken through section D-D of Figure 6A;

[0069] Figures 7A to 7Q provide a detailed sequence of schematic views of a block transfer apparatus illustrating controlled movements thereof;

[0070] Figure 8A is a perspective view of a further example of a block transfer apparatus;

[0071] Figure 8B is a further perspective view of the block transfer apparatus of Figure 8A;

[0072] Figure 8C is a top view of the block transfer apparatus of Figure 8A;

[0073] Figure 8D is a front view of the block transfer apparatus of Figure 8A;

[0074] Figures 9A to 9F provide a detailed sequence of schematic views of the block transfer apparatus of Figure 8A illustrating controlled movements thereof;

[0075] Figure 10A is a perspective view of a further example of a block transfer apparatus;

[0076] Figure 10B is a front view of the block transfer apparatus of Figure 10A;

[0077] Figure IOC is a further perspective view of the block transfer apparatus of Figure 10A; and,

[0078] Figures 11A to 11E provide a detailed sequence of schematic views of the block transfer apparatus of Figure 10A illustrating controlled movements thereof.

Detailed Description of the Preferred Embodiments

[0079] An example of a clamping assembly 10 for clamping a block will now be described with references to Figures 1A to ID.

[0080] The term "block" used herein is a piece of material, typically in the form of a polyhedron, such as a cuboid having six quadrilateral and more typically substantially rectangular faces. The block is typically made of a hard material and may include openings or recesses, such as cavities or the like. The block is configured to be used in constructing a structure, such as a building or the like and specific example blocks include bricks, besser blocks, concrete masonry units or similar.

[0081] In this example, the clamping assembly 10 includes a pair of gripper jaws 20, 30 including datum surfaces 21, 31 and 22, 32 in first and second orthogonal planes to locate the block relative thereto. The clamping assembly 10 is configured to locate an end and top or bottom face of the block in the first and second orthogonal planes and then apply a clamping force to opposing sides of the block so as to locate the block in a third plane orthogonal to both the first and second planes to thereby datum the position of the block with respect to the clamping assembly 10.

[0082] An advantage of the above-described clamping assembly 10 is its ability to provide a reliable and repeatable mechanical datum for the block it is clamping. This is particularly useful in a robotic system in which the clamping assembly may be used to clamp a block and transfer it for pick up by a robotic arm. As the position and orientation of the block is known relative to the clamping assembly, the block may be accurately transferred to the robotic arm and the robotic arm may be programmed to pick up the block from a precise location with respect to the clamping assembly. This enables a further clamp (i.e. end effector) of the robotic arm to pick up a block in the same position every time which is important to ensure that the block is placed accurately at its target destination. The ability to mechanically datum the block in the gripper jaws removes the need for a vision system to image the block in the clamping assembly in order to determine its precise 6DOF location. By eliminating the need for a camera-based vision system, the robotic block transfer system is made more reliable and efficient.

[0083] A number of further features will now be described.

[0084] In one example, the datum surfaces form a V-shaped wedge into which the block is located. This corresponds to the intersection of the X and Z planes in Figures 1C and ID. As will be described in further detail below, typically the block is allowed to drop into the wedge under the force of gravity when the clamping assembly is oriented at an acute angle, typically around 45 degrees to the ground. [0085] Typically, each gripper jaw includes at least one first datum surface extending at least partially between top and bottom surfaces of the gripper jaw and towards the opposing gripper jaw for locating an end of the block. The at least one first datum surface is provided by one of a surface integral with each gripper jaw or a plate element mounted to a surface integral with each gripper jaw. In an example configuration, a thin wear plate/strip, for example made from Steel or the like is fixed to the surface integral with each gripper jaw. These strips or inserts can be replaced periodically when the datum surface starts to wear and this obviates the need to replace the entire gripper jaw.

[0086] Further, each gripper jaw includes at least one second datum surface that is parallel to a top or bottom surface of the gripper jaw and projects towards the opposing gripper jaw for locating the top or bottom surface of the block. The at least one second datum surface is provided by one of the top or bottom surface of each gripper jaw or plate elements mounted to the top or bottom surfaces of each gripper jaw. It will be appreciated therefore that the datum surfaces could be surfaces machined into the body of each gripper jaw, whilst in other embodiments the datum surfaces may be provided by additional plate elements fixed to surfaces of the gripper jaw.

[0087] In one example, the at least one second datum surface is discontinuous. In this regard, the top or bottom surface of each gripper jaw and/or plate elements fixed thereto may be segmented so as to provide gaps suitable for a gripper of a robotic arm to grip the block whilst it is held by the clamping assembly to effect transfer to the robotic arm. It is to be appreciated that in order to datum the block in the at least one second datum plane contact with one or more surface segments or plate elements may be used. In some examples, depending on the length of block being clamped, more than one surface segment or plate element providing the second datum surface will be in contact with the block whereas for shorter blocks only one surface segment or plate element may contact the block.

[0088] The gripper jaws of the clamping assembly may therefore be configured to accommodate blocks of varying length. In one example, the jaws may accommodate one or more of a full-size block of length L, a three-quarter size block of length 0.75L, a half-size block of length 0.5L and a quarter-size block of length 0.25L. [0089] Typically, the gripper jaws are configured to clamp blocks of varying length at different pre-defmed positions along the length of the gripper jaws. In this regard, each gripper jaw may include a plurality of first datum surfaces spaced apart along a lengthwise direction thereof. The plurality of spaced apart first datum surfaces are typically further stepped apart laterally with respect to each gripper jaw so as not to overlap in the lengthwise direction thereof. In this arrangement, an end of blocks of varying length are each located on one of the plurality of first datum surfaces of each gripper jaw. Accordingly, when a particular block type is held by the clamping assembly in a datumed configuration, only one of the plurality of first datum surfaces will be in contact with the block.

[0090] The clamping method of the gripper jaws will now be described. Typically, a first of the pair of gripper jaws has a plurality of first gripper pads arranged to define the third plane for locating a side face of the block when clamped. The plurality of first gripper pads may be mounted onto an inner face of the first gripper jaw or into recesses formed therein such that the pads protrude slightly past the inner face. In one example, the plurality of first gripper pads comprise a pair of spaced apart rows of first gripper pads extending in a lengthwise direction of the first gripper jaw. In a preferred arrangement, at least four first gripper pads will contact a first side face of the block when clamping. Typically, this comprises two first gripper pads in the first row and two first gripper pads in the second row. This arrangement will provide four points of contact typically whereby the gripper pads in the first and second rows are equally spaced apart in the lengthwise direction.

[0091] A second of the pair of gripper jaws typically has a plurality of second gripper pads arranged co-linearly in a lengthwise direction thereof such that when a clamping force is applied to the block the plurality of second gripper pads act to urge the block into planar alignment with the third plane defined by the plurality of first gripper pads. In this regard, the second gripper pads are typically located on the second gripper jaw approximately midway between the spaced apart rows of first gripper pads. In this way, the line of action of the clamping force through the second gripper pads will be midway between the corresponding lines of action of the clamping force through the first gripper pads. This arrangement assists in providing planar alignment in the third plane (i.e. Y-plane) and prevents the block from being angularly misaligned in the jaws. [0092] The first and second gripper pads are arranged on stepped surfaces of each gripper jaw so that each different length of block clamped by the assembly is contacted by a different plurality of first and second gripper pads.

[0093] In one example, any block clamped by the assembly will be in contact with at least four first gripper pads and at least two second gripper pads when a clamping force is applied. In other arrangements it may be possible to for a block to be in contact with only three first gripper pads and one second gripper pad.

[0094] It is to be understood that when a block is clamped by the above-described clamping assembly it may be held initially in an undatumed and unknown position. In order to datum the block in the jaws, typically the block is allowed to drop into the wedge under gravity to locate onto the datum surfaces defining the first and second orthogonal planes.

[0095] In order to effect this drop, typically the clamping assembly is pivotable (either directly or indirectly) and the drop is performed when the gripper jaws have been pivoted to a relative angle to the ground of at least one of: between 30 to 60 degrees; between 35 to 55 degrees; between 40 to 50 degrees; and, approximately 45 degrees. As the jaws must be opened in order to allow the block to drop, the angle is chosen for a particular block type to ensure that the block is not inadvertently dropped out of the clamping assembly.

[0096] In operation, in one example, the block is initially clamped in the gripper jaws in an approximate position. It is then rotated to a drop position whereby the gripper jaws release the block and allow it to drop into the wedge. The block is then re-clamped when it is located in the wedge so that the block is then clamped in a datumed position.

[0097] In another broad form there is provided a block transfer apparatus for transferring a block between an upstream clamp of a block delivery system and a downstream clamp of the block delivery system. The block transfer apparatus includes a frame pivotally mounted to a support; and, a clamping assembly mounted to the frame and linearly extendable relative thereto, the clamping assembly including a pair of gripper jaws including datum surfaces in first and second orthogonal planes to locate the block relative thereto. The clamping assembly is configured to at least: receive a block from the upstream clamp, wherein the block is initially clamped in the gripper jaws in an approximate position; rotate to a drop position whereby the gripper jaws release the block and allow it to drop into a V-shaped wedge formed by the datum surfaces to thereby locate an end and top or bottom face of the block in the first and second orthogonal planes; re-clamp the block after the drop by applying a clamping force to opposing sides of the block so as to locate the block in a third plane orthogonal to both the first and second planes to thereby datum the position of the block with respect to the clamping assembly. Finally, the block transfer apparatus presents the block clamped in the datumed position for transfer to the downstream clamp.

[0098] In one example, the support comprises a distal end of a boom used for transferring blocks therealong and the upstream clamp forms part of a shuttle for delivering a block along the boom.

[0099] The downstream clamp may be an end effector of a robotic block placement arm that is programmed to place blocks during construction of a building structure.

[0100] In some arrangements, the block transfer apparatus includes a distance range sensor for use in determining the proximity between the clamping assembly and the block held by the upstream clamp. Any suitable distance range sensing technology such as ultrasonic, laser etc may be used. Feedback from the distance sensor can be used to control the block transfer apparatus to pick up the block from the upstream clamp.

[0101] In a further broad form, there is provided a block delivery system for delivering blocks for placement during construction of a building structure. The block delivery system includes a boom for transferring blocks therealong; an upstream clamp forming part of a shuttle that delivers blocks along the boom; a downstream clamp associated with an end effector of a robotic block placement arm that is programmed to place blocks during construction of the building structure; and, a block transfer apparatus for transferring a block between the upstream clamp and the downstream clamp, the block transfer apparatus including: a frame pivotally mounted to a distal end of the boom; and, a clamping assembly mounted to the frame and linearly extendable relative thereto, the clamping assembly including a pair of gripper jaws including datum surfaces in first and second orthogonal planes to locate the block relative thereto, wherein the clamping assembly is configured to at least: receive a block from the upstream clamp, wherein the block is initially clamped in the gripper jaws in an approximate position; rotate to a drop position whereby the gripper jaws release the block and allow it to drop into a V-shaped wedge formed by the datum surfaces to thereby locate an end and top or bottom face of the block in the first and second orthogonal planes; re-clamp the block after the drop by applying a clamping force to opposing sides of the block so as to locate the block in a third plane orthogonal to both the first and second planes to thereby datum the position of the block with respect to the clamping assembly; and, present the block clamped in the datumed position for transfer to the downstream clamp.

[0102] Referring again to Figures 1A to ID, the clamping assembly 10 will be described in further detail. The clamping assembly 10 includes a frame 11 to which the gripper jaws 20, 30 are slidably mounted onto rails 14, 16 via bearing blocks or rail guides for linear movement in a lateral direction in order to open and close the jaws. The jaws 20, 30 are belt driven by a servo motor 17 that turns a lead screw 15 connecting the jaws to thereby move the jaws along the rails 14, 16 in order to apply and release a clamping force to a block. Further bearing blocks or rail guides 12, 13 are also mounted to one side of the frame 11 and these guides are engageable onto rails of a block transfer apparatus as will be described in further detail below.

[0103] As shown in Figures 1A and IB, first gripper jaw 20 includes two rows of spaced apart gripper pads 41, 42 along the length of the first griper jaw 20, whilst second gripper jaw 30 includes a single row of spaced apart gripper pads 43 along the length of second gripper jaw 30. These gripper pads exert a clamping force onto a block when clamped and are arranged so that the gripper pads 43 of the second gripper jaw 30 urge the block into planar alignment in a Y-plane defined by the gripper pads 41, 42 of the first gripper jaw 20 in contact with the block. In this regard, the single row of gripper pads 43 of the second gripper jaw 30 are typically located approximately midway between the height of the two rows defined respectively by gripper pads 41, 42 of the first gripper jaw 20. This arrangement prevents angular misalignment or twisting of the block in the jaws.

[0104] Each gripper jaw 20, 30 of the clamping assembly has a body extending in a lengthwise direction. In plan view, the gripper jaws 20, 30 each have a central portion 25, 35 and fore and aft portions 26, 36 and 27, 37 that are inwardly tapered from the central portion 25, 35 towards respective opposing ends of each jaw 20, 30. Internally, the body of each gripper jaw has a central recessed portion, from which the body defines a stepped profile in opposing directions towards respective ends of each jaw. The inner face of each jaw therefore defines a number of laterally stepped apart recessed portions, each defining a recessed inner surface and corresponding lip segment as will be described in further detail below with respect to the schematic views shown in Figures 3A to 3C, 4A to 4C, 5A to 5C and 6A to 6C.

[0105] In Figure ID, it is to be noted that the clamping assembly 10 includes a plurality of first datum surfaces 21, 31 that are stepped apart in a lengthwise direction of the gripper jaws 20, 30. Advantageously, this enables the clamping assembly 10 to be able to clamp and datum blocks of varying length which increases its utility. There may also be provided a plurality of second datum surfaces 22, 32 as shown that have gaps between them suitable for a clamp of a robot to grip the block whilst held by the clamping assembly 10 for transfer thereto.

[0106] An example of a block transfer apparatus 200 is provided in Figure 2. In this example, the block transfer apparatus 200 includes a lengthwise extending frame or bracket 210 to which the clamping assembly 10 is translatably mounted for linear extension and retraction therealong about rails 215, 216. The rail guides 12, 13 mounted to the frame 11 of the clamping assembly 10 receive the rails 215, 216 therein and the clamping assembly 10 is belt driven along the rails by servo motor 220. In use, the block transfer apparatus 200 is pivotally mounted to a support (such as a distal end of a boom) to enable controlled rotation about pivot axis P. In the example shown, the bracket 210 has structural cross bracing support 212 attached thereto and a pivot mount 213 is provided on this support. On the opposing side, a pivot mount 214 which may be in the form of a high precision reduction gearing is provided mounted to the bracket 210. Mounted beneath the bracket 210 is an adhesive applicator 230 for dispensing construction adhesive onto the block 1. In use, the block is translated beneath nozzles of the adhesive applicator in order to apply adhesive along a substantial length of the block surface. Further details of operation of the block transfer apparatus 200 are described below with references to Figures 7A to 7Q.

[0107] Referring now to Figures 3A to 3C, 4A to 4C, 5A to 5C and 6A to 6C, there are shown detailed schematic representations of a clamping assembly 100 for use in clamping various block types in a datumed position. In these figures, the nomenclature of first and second gripper jaws is the opposite of that used with respect to Figures 1A to ID.

[0108] In the below description, each gripper jaw of the clamping assembly has a body extending in a lengthwise direction. In plan view, the gripper jaws have a central portion and fore and aft portions that are inwardly tapered from the central portion towards respective opposing ends of each jaw. Internally, the body of each gripper jaw has a central recessed portion, from which the body defines a stepped profile in opposing directions towards respective ends of each jaw. The inner face of each jaw therefore defines a number of laterally stepped apart recessed portions, each defining a recessed inner surface and corresponding lip segment.

[0109] It is to be understood that at least some of the lips define the plurality of first datum surfaces spaced apart along a lengthwise direction of each jaw and stepped apart laterally so as not to overlap in the lengthwise direction thereof.

[0110] In Figures 3A to 3C, the clamping assembly 100 is shown clamping a quarter-length block 1 having a single core or cavity therethrough, although this is for purposes of illustration only.

[0111] In this arrangement, the block 1 is clamped in the central recessed portion of the jaws 110, 150 between first recessed inner surfaces 111, 151. The end face 3 of the block 1 is in contact with first lip segments 121, 161 that define first datum surfaces in the X-plane. In this example, first insert wear strips 140, 180 are fixed onto the corresponding first lip segments 121, 161 and the block 1 is held in contact with these strips. A top or bottom face 6 of the block 1 is in contact with plate elements 144, 184 that are fixed to the top surface of respective jaws 110, 150 proximate the central portion thereof. These plate elements 144, 184 project inwardly so as to at least partly extend above the central recessed portion of the jaws. The plate elements 144, 184 define second datum surfaces in the Z-plane and accordingly in the clamped configuration shown, the block 1 is datumed in the X and Z planes.

[0112] Respective sides 4 and 5 of the block 1 are clamped respectively by first gripper pads 130, 131 and 130’, 13 that are fixed proximal first recessed inner surface 111 of the first gripper jaw 110 and second gripper pads 170, 171 that are fixed proximal first recessed inner surface 151 of the second gripper jaw 150. As shown in Figure 3B, the first gripper pads are arranged in spaced apart rows with first gripper pads 130, 131 being in an upper row and first gripper pads 130’, 13 G being in a lower row so as to position first gripper pad 130 above first gripper pad 130’ and first gripper pad 131 above first gripper pad 13 G. The second gripper pads 170, 171 are arranged co-linearly in a single row that is centrally disposed between the two rows of first gripper pads.

[0113] In this way, when a clamping force is applied to the block 1, the plurality of second gripper pads 170, 171 act to urge the block into planar alignment with a third plane (the Y- plane) defined by the surfaces of the plurality of first gripper pads 130, 131, 130’, 13G. This arrangement of gripper pads prevents angular misalignment when the block is clamped as side face 4 of the block 1 has four points of contact and side face 5 has two points of contact disposed midway between the opposing points of contact on the other side. As such, in this configuration the position of the block 1 is datumed in the X, Y and Z planes relative to the clamping assembly 100.

[0114] In Figures 4A to 4C, the clamping assembly 100 is shown clamping a half-length block 1 having a two cores or cavities therethrough, although this is for purposes of illustration only.

[0115] In this arrangement, the block 1 is clamped by respective fore and aft portions of each gripper jaw 110, 150, between second recessed inner surfaces 112, 152 in the aft portion and second recessed inner surfaces 113, 153 in the fore portion. The end face 3 of the block 1 is in contact with second lip segments 123, 163 that define first datum surfaces in the X-plane. In this example, second insert wear strips 141, 181 are fixed onto the corresponding second lip segments 123, 163 and the block 1 is held in contact with these strips. A top or bottom face 6 of the block 1 is in contact with plate elements 145, 185 that are fixed to the top surface of respective fore portions of the gripper jaws 110, 150 so as to project inwardly past the second recessed inner surfaces 113, 153. In addition, the top or bottom face 6 of the block 1 is also in contact with plate elements 146, 186 that are fixed to the top surface of respective aft portions of the gripper jaws 110, 150 so as to project inwardly past the second recessed inner surfaces 112, 152. The plate elements 145, 146, 184, 186 define second datum surfaces in the Z-plane and accordingly in the clamped configuration shown, the block 1 is datumed in the X and Z planes.

[0116] Side 4 of the block 1 is clamped respectively by first gripper pads 132, 132’ that are fixed proximal second recessed inner surface 112 of the first gripper jaw 110 and first gripper pads 133, 133’ that are fixed proximal second recessed inner surface 113 of the first gripper jaw 110. Side 5 of the block 1 is clamped respectively by second gripper pad 172 that is fixed proximal second recessed inner surface 152 of the second gripper jaw 150, and second gripper pad 173, that is fixed proximal second recessed inner surface 153 of the second gripper jaw 150. The respective first and second gripper pads are arranged substantially as previous described, except spaced apart further in a lengthwise direction of the gripper jaws. As the block 1 is clamped, the plurality of second gripper pads 172, 173 act to urge the block into planar alignment with a third plane (the Y-plane) defined by the surfaces of the plurality of first gripper pads 132, 133, 132’, 133’. As such, in this configuration the position of the block 1 is datumed in the X, Y and Z planes relative to the clamping assembly 100.

[0117] In Figures 5 A to 5C, the clamping assembly 100 is shown clamping a three quarter- length block 1 having a three cores or cavities therethrough, although this is for purposes of illustration only.

[0118] In this arrangement, the block 1 is clamped by respective fore and aft portions of each gripper jaw 110, 150, between third recessed inner surfaces 114, 154 in the aft portion and third recessed inner surfaces 115, 155 in the fore portion. The end face 3 of the block 1 is in contact with third lip segments 125, 165 that define first datum surfaces in the X-plane. In this example, third insert wear strips 142, 182 are fixed onto the corresponding third lip segments 125, 165 and the block 1 is held in contact with these strips. A top or bottom face 6 of the block 1 is in contact with plate elements 145, 185 that are fixed to the top surface of respective fore portions of the gripper jaws 110, 150 so as to project inwardly past the third recessed inner surfaces 115, 155. In addition, the top or bottom face 6 of the block 1 is also in contact with plate elements 146, 186 that are fixed to the top surface of respective aft portions of the gripper jaws 110, 150 so as to project inwardly past the third recessed inner surfaces 114, 154. The plate elements 145, 146, 184, 186 define second datum surfaces in the Z-plane and accordingly in the clamped configuration shown, the block 1 is datumed in the X and Z planes.

[0119] Side 4 of the block 1 is clamped respectively by first gripper pads 134, 134’ that are fixed proximal third recessed inner surface 114 of the first gripper jaw 110 and first gripper pads 135, 135’ that are fixed proximal third recessed inner surface 115 of the first gripper jaw 110. Side 5 of the block 1 is clamped respectively by second gripper pad 174 that is fixed proximal third recessed inner surface 154 of the second gripper jaw 150, and second gripper pad 175 that is fixed proximal third recessed inner surface 155 of the second gripper jaw 150. The respective first and second gripper pads are arranged substantially as previous described, except spaced apart further in a lengthwise direction of the gripper jaws than the previous examples. As the block 1 is clamped, the plurality of second gripper pads 174, 175 act to urge the block into planar alignment with a third plane (the Y-plane) defined by the surfaces of the plurality of first gripper pads 134, 135, 134’, 135’. As such, in this configuration the position of the block 1 is datumed in the X, Y and Z planes relative to the clamping assembly 100.

[0120] In Figures 6A to 6C, the clamping assembly 100 is shown clamping a full-length block 1 having a four cores or cavities therethrough, although this is for purposes of illustration only.

[0121] In this arrangement, the block 1 is clamped by respective fore and aft portions of each gripper jaw 110, 150, between fourth recessed inner surfaces 116, 156 in the aft portion and fourth recessed inner surfaces 117, 157 in the fore portion. The end face 3 of the block 1 is in contact with fourth lip segments 127, 167 that define first datum surfaces in the X-plane. In this example, fourth insert wear strips 143, 183 are fixed onto the corresponding fourth lip segments 127, 167 and the block 1 is held in contact with these strips. A top or bottom face 6 of the block 1 is in contact with plate elements 145, 185 that are fixed to the top surface of respective fore portions of the gripper jaws 110, 150 so as to project inwardly past the fourth recessed inner surfaces 117, 157. In addition, the top or bottom face 6 of the block 1 is also in contact with plate elements 146, 186 that are fixed to the top surface of respective aft portions of the gripper jaws 110, 150 so as to project inwardly past the fourth recessed inner surfaces 116, 156. The plate elements 145, 146, 184, 186 define second datum surfaces in the Z-plane and accordingly in the clamped configuration shown, the block 1 is datumed in the X and Z planes.

[0122] Side 4 of the block 1 is clamped respectively by first gripper pads 136, 136’ that are fixed proximal fourth recessed inner surface 116 of the first gripper jaw 110 and first gripper pads 137, 137’ that are fixed proximal fourth recessed inner surface 117 of the first gripper jaw 110. Side 5 of the block 1 is clamped respectively by second gripper pad 176 that is fixed proximal fourth recessed inner surface 156 of the second gripper jaw 150, and second gripper pad 177 that is fixed proximal fourth recessed inner surface 157 of the second gripper jaw 150. The respective first and second gripper pads are arranged substantially as previous described, except spaced apart further in a lengthwise direction of the gripper jaws than the previous examples. As the block 1 is clamped, the plurality of second gripper pads 176, 177 act to urge the block into planar alignment with a third plane (the Y -plane) defined by the surfaces of the plurality of first gripper pads 136, 137, 136’, 137’. As such, in this configuration the position of the block 1 is datumed in the X, Y and Z planes relative to the clamping assembly 100.

[0123] Referring now to Figures 7A to 7Q, the controlled operation of the block transfer apparatus 200 shall be described in the context of a block delivery system 300 for delivering blocks for placement during construction of a building structure.

[0124] In this example, operation of the block transfer between the downstream and upstream clamps 55, 80 of the block delivery system 300 via the block transfer apparatus 200 shall be described. In Figure 7A, a block 1 is being transferred to the downstream clamp 80 which is a robotic gripper of a robotic block placement arm (not shown). As soon as the downstream clamp 80 has gripped the block 1, the clamping assembly 10 of the block transfer apparatus 200 may release the block. In this block handover position, the block transfer apparatus 200 is in a horizontal orientation with the clamping assembly 10 fully extended in the longitudinal direction.

[0125] In Figure 7B, the block transfer apparatus 200 releases the block and begins to rotate away from the downstream clamp 80 about support 52 which is a mount at the distal end of boom 50, the support 52 defining a rotation or pivot axis about which the block transfer apparatus 200 is able to pivot. In this initial phase of rotation, the clamping assembly 10 remains at full extension.

[0126] In Figure 7C, as rotation of the block transfer apparatus 200 continues, the clamping assembly 10 begins to retract and move linearly along rails of the frame or bracket 210 of the block transfer apparatus 200. In Figure 7D, retraction of the clamping assembly 10 continues whilst the block transfer apparatus 200 is rotating and in this state the clamping assembly 10 is now retracted sufficiently to be within the envelope of the frame or bracket 210.

[0127] In Figure 7E, the clamping assembly 10 is shown fully retracted with respect to frame 210 as the block transfer apparatus 200 approaches a nearly vertical orientation. In Figure 7F, the block transfer apparatus 200 has rotated past vertical and the clamping assembly 10 has begun to extend away from its fully retracted position. In this state, the orientation of the clamping assembly 10 has “flipped” over from the initial orientation shown in Figure 7A.

[0128] The block transfer apparatus 200 continues rotation until the longitudinal axis of the frame 210 is aligned with the lengthwise direction of the boom 50 as shown in Figure 7F. In this state, the clamping assembly 10 is nearly fully extended so as to reach into the opening 51 of the distal end of the boom 50. Typically, there is a recess or cut-out in the underside portion of the distal end of the boom so that the block transfer apparatus 200 can enter the envelope of the boom without any physical clash. Depending on the size of the cut-out, the clamping assembly 10 may be able to reach full extension during rotation. Otherwise, the block transfer apparatus 200 rotates into alignment with the boom 50 first and then extends the clamping assembly 10 into the boom 50.

[0129] As shown in Figure 7H, the clamping assembly 10 is then fully extended into a position whereby it clamps a block held by the downstream clamp 55 disposed inside the boom 50. The downstream clamp 55 typically forms part of a shuttle mechanism that delivers blocks internally through the boom 50. Once the clamping assembly 10 has clamped the block, the downstream clamp 55 may release its grip of the block. It is to be understood that the position of the block with respect to the gripper jaws of the clamping assembly 10 is not precisely known at this stage. [0130] In Figures 71 and 7J, the clamping assembly 10 is shown beginning to retract away from its fully extended position whilst the frame 210 remains in alignment with the boom 50. In Figure 7J, the clamping assembly 10 has retracted sufficiently so that it is within the cut out portion of the underside of the distal end of the boom in a safe position for rotation of the block transfer apparatus 200 to begin.

[0131] In Figure 7K, the block transfer apparatus 200 is rotated to a horizontal orientation whilst the clamping assembly 10 remains in an extended state (retracted only a sufficient amount to clear the distal end of the boom upon exit thereof). An adhesive applicator (see Figure 2A) mounted to the block transfer apparatus 200 then begins dispensing adhesive onto an upper face of the block whilst the clamping assembly 10 retracts the block and thereby translates it linearly beneath nozzles of the adhesive applicator. Once the adhesive dispensing is complete and when the clamping assembly 10 is nearly fully retracted as shown in Figure 7L the block transfer apparatus 200 rotates to a drop position in which the block is datumed.

[0132] The drop position is shown in Figure 7M. In this example, the block transfer apparatus 200 and clamping assembly 10 are oriented at an angle to the ground of approximately 45 degrees. In this position, the clamping assembly 10 releases its clamp of the block and allows it to drop under gravity into the wedge 70 defined by the first and second datum surfaces as previously described which thereby datums the block in the clamping assembly 10 with respect to the X and Z planes as shown. Once the drop has been performed and the block is datumed in these planes, the gripper jaws of the clamping assembly 10 re clamp the block to thereby locate the block in a third plane orthogonal to both the first and second planes to thereby fully datum the position of the block with respect to the clamping assembly 10.

[0133] After the drop is complete and the block is re-clamped in the gripper jaws, the block transfer apparatus 200 commences further rotation at a safe speed as shown in Figure 7N. The block transfer apparatus 200 continues to rotate whilst the clamping assembly 10 is extended to the edge of the frame 210 as shown in Figure 70. Rotation speed is then decreased whilst the clamping assembly 10 continues to extend beyond the frame 210 as shown in Figure 7P. [0134] In Figure 7Q, the final stage of rotation of the block transfer apparatus 200 and extension of the clamping assembly 10 is completed resulting in the block being held out in a substantially horizontal position for transfer to the upstream clamp 80 as shown in Figure 7A. The cycle then repeats as further blocks are transferred by the block delivery system for laying by the robotic placement arm on a construction site in order to construct a building. It is to be noted that in the transfer position shown in Figure 7A, the clamping assembly 10 has been flipped 180 degrees from its orientation when adhesive was applied to the block in Figure 7L. As such the block is now oriented in the clamping assembly 100 such that the face with adhesive applied is now facing downward ready for laying.

[0135] A second example of a block transfer apparatus 500 shall now be described with reference to Figures 8A to 8D and 9A to 9F.

[0136] In this example, the block transfer apparatus 500 is for transferring a block 1 between an upstream clamp (not shown) of a block delivery system and a downstream clamp 80 of the block delivery system. The block transfer apparatus 500 includes a frame 510 pivotally mounted to a support and a clamping assembly 400 mounted to the frame 510 and linearly extendable relative thereto, the clamping assembly 400 including a pair of gripper jaws 420, 430 for clamping opposing sides of the block.

[0137] The block transfer apparatus 500 is configured to receive a block 1 from the upstream clamp, wherein the block 1 is initially clamped in the gripper jaws 420, 430 in an approximate position; rotate to a drop position whereby the gripper jaws 420, 430 release the block 1 and allow it to self-datum onto first and second orthogonal datum surfaces 424, 434 and 518 to thereby register an end and top or bottom face of the block in corresponding first and second orthogonal planes; re-clamp the block 1 after the drop by applying a clamping force to opposing sides of the block so as to register the block 1 against a third datum surface 422, 423 defining a third plane orthogonal to both the first and second planes to thereby datum the position of the block 1 with respect to the clamping assembly 400; and, present the block 1 clamped in the datumed position for transfer to the downstream clamp 80.

[0138] In this example, the clamping assembly 400 includes a frame 411 to which the gripper jaws 420, 430 are slidably mounted onto rails 441, 442 via bearing blocks or rail guides for linear movement in a lateral direction in order to open and close the jaws. The jaws 420, 430 may be belt driven by a servo motor that turns a lead screw 443 connecting the jaws to thereby move the jaws along the rails 441, 442 in order to apply and release a clamping force to a block.

[0139] The first gripper jaw 420 includes two rows of spaced apart gripper pads 422, 423 rigidly mounted to an inner face 421 along the length of the first gripper jaw 420, whilst the second gripper jaw 430 includes a single row of spaced apart gripper pads 431, 43 mounted to a distal end of flexible fingers or battens 432, 432’ along the length of second gripper jaw 430. The gripper pads exert a clamping force onto a block when clamped and are arranged so that the gripper pads 431, 43 G of the second gripper jaw 430 urge the block into planar alignment in a Y-plane defined by the gripper pads 422, 423 of the first gripper jaw 420 in contact with the block. In this regard, the single row of gripper pads 431, 43 G of the second gripper jaw 430 are typically located approximately midway between the height of the two rows defined respectively by gripper pads 422, 423 of the first gripper jaw 420. This arrangement prevents angular misalignment or twisting of the block in the jaws.

[0140] The flexible finger members or battens 432, 432’ spaced apart along the length of the second gripper jaw 430, allow the pads 431, 43 G to flex laterally and compensate for variations in flatness of the side of the block along its length (which may for instance be slightly bowed) as well as any lateral flex in the gripper jaws themselves. This ensures an equal clamping force is applied along the length of the block as each finger will flex to a different degree depending on the variation in flatness. Some of the flexible fingers 432’ are partially restrained by retaining clips 433 that act to pretension the finger members. Each flexible finger is located at its base into a recessed portion 436 of the second gripper jaw 430.

[0141] The block transfer apparatus 500 further includes a lengthwise extending frame 510 to which the clamping assembly 400 is translatably mounted for linear extension and retraction therealong about rails 515, 516. Rail guides or bearing blocks mounted to the frame 411 of the clamping assembly 400 receive the rails 515, 516 therein and the clamping assembly 400 is belt driven along the rails by servo motor 520. In use, the block transfer apparatus 500 is pivotally mounted to a support (such as a distal end of a boom) to enable controlled rotation about pivot axis P. In the example shown, the frame 510 has structural cross bracing support 512 attached thereto and a pivot mount 513 is provided on this support. On the opposing side, a pivot mount 514 which may be in the form of a high precision reduction gearing is provided mounted to the frame 510. Additionally, a datum bar or plate 517 is mounted to the structural support 512 so that it extends in a direction parallel to the lengthwise direction of the gripper jaws 420, 430. This datum bar 517 is used to datum the top or bottom face of the block as will be described in further detail below. In this example, the distal ends 424, 434 of the gripper jaws provide datum surfaces which register an end face of the block.

[0142] Referring now to Figures 9A to 9F, the controlled operation of the block transfer apparatus 500 shall be described in the context of a block delivery system for delivering blocks for placement during construction of a building structure.

[0143] In this example, operation of the block transfer between the downstream and upstream clamps of the block delivery system via the block transfer apparatus 500 shall be described.

[0144] In Figure 9A, the block transfer apparatus 500 is shown with its clamping assembly 400 extended out and reaching into a boom 50 to receive a block 1 from a downstream clamp (not shown) such as a shuttle clamp that runs along the boom element 50. In this example, the clamping assembly 400 has been rotated about axis 52 in a counter-clockwise direction through a recess or cut-out in the underside portion of the distal end of the boom so that the block transfer apparatus 500 can enter the envelope of the boom without any physical clash. Depending on the size of the cut-out, the clamping assembly 400 may be able to reach full extension during rotation. Otherwise, the block transfer apparatus 500 rotates into alignment with the boom 50 first and then extends the clamping assembly 400 into the boom 50. Once the clamping assembly 400 has clamped the block, the downstream clamp may release its grip of the block. It is to be understood that the position of the block with respect to the gripper jaws of the clamping assembly 400 is not precisely known at this stage.

[0145] In Figures 9B and 9C, the clamping assembly 400 is shown rotating out of the boom in a clockwise direction and starting to retract away from its fully extended position in preparation for the block datuming operation. In Figure 9D, when the block transfer apparatus 500 is in the drop position (oriented at an angle to the ground of approximately 45 degrees), the clamping assembly 400 releases its clamp of the block and allows it to drop under gravity so that the block self-datums onto first and second orthogonal datum surfaces (424, 434) and 518 to thereby register an end and top or bottom face of the block in corresponding first and second orthogonal planes. This datums the blocks with respect to the X and Z planes as depicted in Figures 8C and 8D. Once the drop has been performed and the block is datumed in these planes, the gripper jaws of the clamping assembly 400 re-clamp the block by applying a clamping force to opposing sides of the block so as to register the block against a third datum surface defining a third plane (Y plane) orthogonal to both the first and second planes to thereby datum the position of the block with respect to the clamping assembly 400.

[0146] After the drop is complete and the block is re-clamped in the gripper jaws, the block transfer apparatus 500 commences further rotation in a clockwise direction whilst concurrently extending the clamping assembly 400 out in a horizontal disposition as shown in Figure 9E. In this example, during extension, the block may be translated over a transfer adhesive applicator to apply adhesive to the bottom surface of the block. In this position, the block is held out for transfer to the upstream clamp 80 (e.g. end effector of robotic block placement arm) as shown in Figure 9F from which it is subsequently laid in position.

[0147] A third example of a block transfer apparatus 700 shall now be described with reference to Figures 10A to IOC and 11A to 1 IE.

[0148] In this example, the block transfer apparatus 700 is for transferring a block 1 between an upstream clamp of a block delivery system and a downstream clamp of the block delivery system as previously described. The block transfer apparatus 700 includes a frame 710 pivotally mounted to a support and a clamping assembly 600 mounted to the frame 710 and linearly extendable relative thereto, the clamping assembly 600 including a pair of gripper jaws 620, 630 for clamping opposing sides of the block.

[0149] The block transfer apparatus 700 is configured to receive a block 1 from the upstream clamp, wherein the block 1 is initially clamped in the gripper jaws 620, 630 in an approximate position; rotate to a drop position whereby the gripper jaws 620, 630 release the block 1 and allow it to self-datum onto first and second orthogonal datum surfaces 626, 718 to thereby register an end and top or bottom face of the block in corresponding first and second orthogonal planes; re-clamp the block 1 after the drop by applying a clamping force to opposing sides of the block so as to register the block 1 against a third datum surface 622, 623 defining a third plane orthogonal to both the first and second planes to thereby datum the position of the block 1 with respect to the clamping assembly 600; and, present the block 1 clamped in the datumed position for transfer to the downstream clamp.

[0150] In this example, the clamping assembly 600 includes a frame 611 to which the gripper jaws 620, 630 are slidably mounted onto rails 641, 642 via bearing blocks or rail guides for linear movement in a lateral direction in order to open and close the jaws. The jaws 620, 630 may be belt driven by a servo motor that turns a lead screw 643 connecting the jaws to thereby move the jaws along the rails 641, 642 in order to apply and release a clamping force to a block.

[0151] The first gripper jaw 620 includes two rows of spaced apart gripper pads 622, 623 rigidly mounted to an inner face 621 along the length of the first gripper jaw 620, whilst the second gripper jaw 630 includes two rows of spaced apart gripper pads 632, 634 mounted to a distal end of flexible fingers or battens 633,635 along the length of second gripper jaw 630. The gripper pads exert a clamping force onto a block when clamped and are arranged so that the gripper pads 632, 634 of the second gripper jaw 630 urge the block into planar alignment in the third datum plane defined by the gripper pads 622, 623 of the first gripper jaw 620 in contact with the block. In this regard, the two rows of gripper pads 632, 634 of the second gripper jaw 630 are close together and are typically located approximately midway between the height of the two rows defined respectively by gripper pads 622, 623 of the first gripper jaw 420. This arrangement prevents angular misalignment or twisting of the block in the jaws.

[0152] The flexible finger members or battens 633, 635 spaced apart along the length of the second gripper jaw 430, allow the pads 634, 636 to flex laterally and compensate for variations in flatness of the side of the block along its length (which may for instance be slightly bowed). This ensures an equal clamping force is applied along the length of the block as each finger will flex to a different degree depending on the variation in flatness. Each flexible finger is located at its base into a respective upper and lower cap 636, 637 mounted along respective top and bottom edges of the second gripper jaw 430 so as to pretension the gripper pads. In this arrangement, the gripper pads 432, 434 alternate in position between the first and second rows.

[0153] The block transfer apparatus 700 further includes a lengthwise extending frame 710 to which the clamping assembly 600 is translatably mounted for linear extension and retraction therealong about rails 715, 716. Rail guides or bearing blocks mounted to the frame 611 of the clamping assembly 600 receive the rails 715, 716 therein and the clamping assembly 600 is belt driven along the rails by a servo motor. In use, the block transfer apparatus 700 is pivotally mounted to a support (such as a distal end of a boom) to enable controlled rotation about pivot axis P. In the example shown, the frame 710 has U-shaped support 712 mounted to the frame 710 to which a datum bar or plate 717 is mounted so that it extends in a direction parallel to the lengthwise direction of the gripper jaws 620, 630. This datum bar 717 is used to datum the top or bottom face of the block as will be described in further detail below. In this example, a datum bracket 626 is mounted to a proximate end of the support structure of gripper jaw 620 and this bracket provides a datum surface which registers an end face of the block. In other examples, another datum bracket 626 could be installed in a similar manner in association with gripper jaw 630.

[0154] Referring now to Figures 11A to 11E, the controlled operation of the block transfer apparatus 700 shall be described in the context of a block delivery system for delivering blocks for placement during construction of a building structure.

[0155] In this example, operation of the block transfer between the downstream and upstream clamps of the block delivery system via the block transfer apparatus 700 shall be described.

[0156] In Figure 11A, the block transfer apparatus 700 is shown with its clamping assembly 600 extended out and reaching into a boom 50’ to receive a block 1 from a downstream clamp 55’ such as a shuttle clamp that runs along the boom element 55’. In this example, the clamping assembly 600 has been rotated about axis 52’ in a clockwise direction through a recess or cut-out in the topside portion of the distal end of the boom so that the block transfer apparatus 700 can enter the envelope of the boom without any physical clash. Depending on the size of the cut-out, the clamping assembly 600 may be able to reach full extension during rotation. Otherwise, the block transfer apparatus 700 rotates into alignment with the boom 50’ first and then extends the clamping assembly 600 into the boom 50’. Once the clamping assembly 600 has clamped the block, the downstream clamp 55’ may release its grip of the block. It is to be understood that the position of the block with respect to the gripper jaws of the clamping assembly 600 is not precisely known at this stage.

[0157] In Figure 11B, the clamping assembly 600 is shown rotating out of the boom in a counter-clockwise direction and starting to retract away from its fully extended position in preparation for the block datuming operation. In Figure 11C, when the block transfer apparatus 700 is in the drop position (oriented at an angle to the ground of approximately 45 degrees), the clamping assembly 600 releases its clamp of the block and allows it to drop under gravity so that the block self-datums onto first and second orthogonal datum surfaces 626 and 718 to thereby register an end and top or bottom face of the block in corresponding first and second orthogonal planes. Once the drop has been performed and the block is datumed in these planes, the gripper jaws of the clamping assembly 600 re-clamp the block by applying a clamping force to opposing sides of the block so as to register the block against a third datum surface defining a third plane orthogonal to both the first and second planes to thereby datum the position of the block with respect to the clamping assembly 600.

[0158] After the drop is complete and the block is re-clamped in the gripper jaws, the block transfer apparatus 700 commences further rotation in a counter clockwise direction whilst concurrently extending the clamping assembly 600 out in a horizontal disposition as shown in Figures 11D and 11E. In this example, during extension, the block may be translated over a transfer adhesive applicator to apply adhesive to the bottom surface of the block. In this position, the block is held out for transfer to the upstream clamp (not shown).

[0159] In at least one example, the above -described clamping assembly provides a reliable and repeatable means to datum a position of a block being clamped relative thereto. In a robotic system, this enables the clamping assembly or block transfer apparatus to which it may be mounted to present a block for transfer to a robotic arm in a known position and orientation. This mechanical system for self-datuming a block enables confidence in the geometric block position and orientation without requiring a camera-based vision system to image the block in the clamping assembly and determine the pose thereof which has inherent limitations in outdoor operating environments in which vibration, light and inconsistent block geometry can cause issues.

[0160] Throughout this specification and claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers. As used herein and unless otherwise stated, the term "approximately" means ±20%.

[0161] Persons skilled in the art will appreciate that numerous variations and modifications will become apparent. All such variations and modifications which become apparent to persons skilled in the art, should be considered to fall within the spirit and scope that the invention broadly appearing before described.