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Title:
A SYSTEM FOR CONSTRUCTION OF A REBAR FIXING STRUCTURE
Document Type and Number:
WIPO Patent Application WO/2021/185980
Kind Code:
A1
Abstract:
A system for construction of a rebar fixing structure comprises at least one stackable building block having a predetermined height and comprising a connecting mechanism for interlocking with another building block to build a stack of building blocks. At least one building block further comprises rebar fixing means configured to releasably connect to a rebar and temporarily fix the rebar in a specific position.

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Inventors:
TROMMER MAX (NO)
HAUGENE DANIEL (NO)
Application Number:
PCT/EP2021/056982
Publication Date:
September 23, 2021
Filing Date:
March 18, 2021
Export Citation:
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Assignee:
REBARTEK AS (NO)
International Classes:
E04C5/20
Domestic Patent References:
WO2013074987A12013-05-23
WO2019048289A12019-03-14
WO2011141614A12011-11-17
WO2018208162A12018-11-15
Foreign References:
US3830032A1974-08-20
US20170320156A12017-11-09
AU2010353079A12012-11-08
US20080028718A12008-02-07
Attorney, Agent or Firm:
ONSAGERS AS (NO)
Download PDF:
Claims:
CLAIMS

1. System for construction of a rebar fixing structure comprising

- at least one stackable building block having a predetermined height and comprising a connecting mechanism for interlocking with another building block to build a stack of building blocks, where at least one building block further comprises rebar fixing means configured to releasably connect to a rebar and temporarily fix the rebar in a specific position.

2. System according to claim 1 comprising a workspace configured to be connected to the connecting mechanism of the building block. 3. System according to one of the above claims, where the workspace comprises a block storage area and a construction area.

4. System according to one of the above claims, where the connecting mechanism comprises a magnet.

5. System according to one of the above claims, where the connecting mechanism comprises slots arranged in the workspace.

6. System according to one of the above claims, where the rebar fixing means comprise at least one movable finger adapted to movable grip a rebar.

7. System according to one of the claims 1-5, where the rebar fixing means comprise a magnet. 8. System according to one of the above claims, comprising means for wireless signal communication and where the rebar fixing means comprises a signal processor configured to receive wireless signals and control the rebar fixing means to connect or disconnect.

9. System according to claim 8, where each of the rebar fixing means’ signal processor have allocated an individual address.

10. System according to one of the previous claims, where the rebar fixing means comprises a rechargeable or non-chargeable battery.

11. System according to one of the previous claims, comprising power cables connected to the rebar fixing means. 12. System according to one of the previous claims, comprising several building blocks where the height of the blocks is one of a number of predetermined heights.

13. System according to one of the previous claims, comprising a robot having a robotic arm and a tool, where the tool is configured to grip the building block and/or a rebar and move it to a desired position.

14. System according to one of the previous claims, comprising anchoring means for anchoring the building blocks.

15. System according to one of the claims 1-13, where the connecting mechanism comprises anchoring means.

Description:
A SYSTEM FOR CONSTRUCTION OF A REBAR FIXING STRUCTURE

The invention regards a system for construction of a rebar fixing structure.

Rebar (short for reinforcing bar) is a steel bar or mesh of steel wires used as a tension device in reinforced concrete and reinforced masonry structures to strengthen and aid the concrete under tension. Concrete is strong under compression but has weak tensile strength. Rebar significantly increases the tensile strength of the structure. Rebar's surface is typically "deformed" with ribs, lugs or indentations to promote a better bond with the concrete and reduce the risk of slippage. To reinforce large structures, there is a need to build rebar fixing structures, cages, corresponding to the concrete/masonry structure to be built.

Rebar cages are fabricated either on or off the project site, commonly with the help of hydraulic benders and shears. The rebars in the cages are joined together by spot welding, tying steel wire, sometimes using an electric rebar tier, or with mechanical connections.

Today it is known to use industrial robots to build rebar fixing structures. There are several advantages with using industrial robots for building the rebar fixing structures, e.g. they can be built quicker, cost of production can be lowered, and an improved control of quality can be achieved. In addition, if having the industrial robots placed on site, large rebar fixing structures can be built efficiently since the need for transportation of these large structures can be avoided.

By using industrial robots, it is also possible to increase the complexity of the rebar fixing structure without risking that production time and/or quality issues increase. More complex rebar fixing structures may e.g. result in that a plurality of different sizes can be used in order optimize the cost of production.

In order to be able to build the rebar fixing structures, the industrial robots are equipped with tools for holding the rebars during the transport as well as during attachment of the rebar, as well as tools for attaching the rebar to other reinforcement bars by welding or tying.

Prior art comprises systems and methods for manufacturing rebar constructions using such robots and tools.

WO2019048289 describes a method for manufacturing a wooden construction of rod-like members. The method uses grippers connected to a vertical fastening plane arranged at an assembly table for holding the rod-like wooden members in position during assembly of the wooden construction. In one embodiment, the grippers are connected to the fastening plane by means of magnetism. The fastening plane can be made by assembling a number of modules, where the number of modules used determines the size of the fastening plane. It also discusses using a robot to place the rod-like members in the grippers.

WO201 1/141614 (AU2010353079) describes the use of robot-based system for building rebar fixing structures and specifically a tool that the robots can use for this purpose. The robotic arms hold and position the rebars during construction.

WO2018/208162 describes a method for providing temporary support for pipes, for example during construction of a pipeline section of end-to-end joined pipes. The method comprises temporarily supporting pipes on temporary support stack assemblies. The temporary support stack assembly is made by arranging substantially identical individual beams in multiple stacked horizontal layers.

US20080028718A1 describes a single use support system for in-situ construction of rebar structures. The support system is cast into the concrete structure. It also lacks fixing means needed for precise positioning. In-situ construction of rebar structures is less desirable than ex-situ prefabrication of rebar, as it happens on the critical path of the project. This system is expensive as the complete support system is cast into the structure, and the elements of the support system cannot be used for other structures.

One challenge to enable large scale ex-situ prefabrication is lack of flexible jig solutions. Rigid jig solutions are a major barrier for mass customized ex-situ prefabrication of rebar cages. Systems with little flexibility require significant human labor to adjust/adapt the jig to the next rebar structure.

There is thus a need for enhanced systems for fixing rebars in a specific position when using robotic arms that are more flexible than existing systems

The object of the invention is to provide a system for positioning rebars in specific positions for constructing a rebar fixing structure that solves the above-mentioned problems with prior art. Another object of this invention is to provide a system for assembling a rebar fixing structure that enable automatic ex-situ construction of rebar cages with robots. It is also an object of the invention to ensure that the elements of the system can be rapidly re-used for subsequent rebar fixing structures, even if the next rebar fixing structure substantially differs from the prior structure.

The object of the invention is achieved by means of the features of the patent claims.

In one embodiment, a system for construction of a rebar fixing structure comprises at least one stackable building block having a predetermined height and comprising a connecting mechanism for interlocking with another building block to build a stack of building blocks. The at least one building block further comprises rebar fixing means configured to releasably connect to a rebar and temporarily fix the rebar in a specific position.

When the system is used, the building blocks are stacked in a configuration that allows the rebars to be assembled in the desired structure. The rebars are temporarily fixed in position by means of the rebar fixing means. While the rebars are fixed in their positions, they are joined together to form a complete rebar cage, for example by means of welding. After the rebar cage has been formed, the fixing means release the rebars. The rebar cage can then be moved away from the rebar fixing structure and the building blocks can be re-used for producing a new, similar or different rebar cage.

In this document, the term temporarily fixed is thus used to describe that the rebars are fixed in a specific position only during the time needed for joining the rebars together to form the final rebar cage.

The invention will be described in more detail by means of examples and by reference to the accompanying figures.

Figure 1 illustrates an example of a system for construction of a rebar fixing structure.

Figure 2 illustrates one stage during the process of constructing a rebar fixing structure using a system according to the invention.

Figure 3 illustrates another stage during the process of constructing a rebar fixing structure.

Figure 4 illustrates another stage during the process of constructing a rebar fixing structure.

Figure 5 illustrates yet another stage during the process of constructing a rebar fixing structure.

Figure 6 illustrates an embodiment of a building block for use in a system for construction of a rebar fixing structure.

Figure 7 illustrates another embodiment of a building block for use in a system for construction of a rebar fixing structure.

Figure 8 illustrates an embodiment of a building block with rebar fixing means for use in a system for construction of a rebar fixing structure.

Figure 9 illustrates another embodiment of a building block with rebar fixing means for use in a system for construction of a rebar fixing structure Figure 10 illustrates another embodiment of a building block with rebar fixing means for use in a system for construction of a rebar fixing structure

Figure 11 illustrates another embodiment of a building block with rebar fixing means for use in a system for construction of a rebar fixing structure.

Figure 12 and 13 illustrates an example of anchoring means for anchoring building blocks.

Figure 14 and 15 illustrates another example of anchoring means for anchoring building blocks.

Figure 1 illustrates an example of a system 10 for construction of a rebar fixing structure. The rebar fixing structure that is constructed by the system consists of an assembly of horizontal rebars 12 and vertical rebars 11 which are connected together to form the desired structure. To be able to connect the rebars as desired, the rebars are fixed in the dedicated positions by means of stackable building blocks 13. The building blocks 13 have a predetermined height and are stacked on top of each other to reach the height necessary for the rebar to be placed in the desired position in the structure. The system is in this example operated by robotic arm 14 and a tool 16. The tool 16 is adapted to grip and move the building blocks and/or the rebars. In one embodiment the same robotic tool can be used both to move the building block and the rebars, but the tool may be interchangeable in order to use specific tools for each element of the system. The building blocks 13 comprise a connecting mechanism for interlocking with another building block in order to provide a stack of building blocks where each block is securely connected to the block below and/or above itself. At least one of the building blocks, for example the uppermost block in each stack, comprises rebar fixing means 18, 19 configured to releasably connect to a rebar and temporarily fix the rebar in a specific position.

Figure la gives a closer look on the rebar fixing means 18, 19 on two building blocks 13. The building block 13 with horizontal rebar fixing means 18 connects to a horizontal rebar 12 and fixes it near its end where it joins a vertical rebar 11. The vertical rebar 11 is in turn connected and fixed in position by vertical rebar fixing means 19. As these rebars are held in fixed position by the rebar fixing means 18,

19, their ends can be joined to form an assembled rebar fixing structure. This process is done several times in order to achieve the structure illustrated in figure 1 or other more or less complex structures.

Figure 2 illustrates the system during operation in an early stage of construction.

The system comprises in this embodiment a workspace 17 where one section near one end works as a block storage area 20 for storing building blocks which are to be used for constructing the rebar fixing structure, and a construction area 21 where the construction is performed. The construction area and block storage area can in other embodiments be separate modules or units.

The workspace is configured to be connected to the building blocks 13 by means of the connecting mechanism. The connecting mechanism can in some embodiments comprise a magnet, for example by making the workspace 17 from a metal or having a metal surface, and the building blocks 13 comprising magnets. The magnets of the building blocks may be arranged at the bottom of the building blocks 13, or the complete building blocks may be magnetic. In one embodiment, the magnets are electromagnets. In other embodiments, the connecting mechanism comprises slots. For example, can the workspace comprise slots in a pattern and the building blocks 13 comprise complimentary shapes, either the shape of the building block itself or the building blocks 13 comprises protrusions which fits into the slots in the workspace. The slots and the corresponding protrusions may be any shape but is in one embodiment circular in order to enable rotation of the building blocks after connection.

In figure 2, there are arranged two rows of simple building blocks 13 and one row of building blocks 13 comprising rebar fixing means 18 in the block storage area 20. The robotic arm 14 reaches towards the block storage area 20, uses the tool 16 to grip one building block 13 and moves it to the construction area 21. In the figure, the robot is in process of building three stacks of building blocks 130, 131, 132, where so far one stack 132 comprises two building blocks, while the two other stacks comprise one building block each. The connecting mechanism can be configured in such a way that the robot can build the stacks autonomously, which enables a fully automatic system with little or no need for operators on site.

In the example in figure 2, the rebar fixing means 18 comprises two movable fingers arranged in a vertical position on the upper surface of some of the building blocks. These building blocks which comprises the rebar fixing means 18, will be positioned on the top of the stack when the stack has reached its desired height according to the predetermined rebar fixing structure. The rebar fixing means 18 will be described in more detail below.

In figure 3, the system is in a subsequent stage of construction. The robot 14 has now stacked more building blocks 13, such that the three stacks 130, 131 and 132 each comprise three building blocks, ie. the robotic arm 14, using the tool 16, has moved five more building blocks from the block storage area 20 to the construction area 21.

Figure 4 and 5 shows further subsequent stages of the construction process. In figure 4 the desired height for the rebar is reached and building blocks comprising rebar fixing means 18 are arranged on top of each stack 130, 131, 132, and a rebar 40 is connected to the rebar fixing means and fixed in place. In figure 5, there are built more stacks and rebars 50 are arranged at the top of the new stacks, perpendicular to the rebar 40.

This process can continue until the desired construction is achieved. Figure 1 illustrates a further stage in the process.

When the rebars are fixed in their desired position, they can be joined by welding or other suitable means to form the final structure as described earlier in this document. When the rebar fixing structure is finalized, the rebar fixing means can release the rebars, the building blocks can be disconnected and disassembled and re used for a new rebar fixing structure. In this way, the system according to the invention is a flexible, reusable system which is suitable for construction of the rebar fixing structure at location remote from the building site.

Figures 6-11 illustrates different types of building blocks that can be used with the system according to the invention.

Figure 6 shows a basic building block 60. This embodiment comprises a cubic building block with a bottom surface 62, a top surface 61 and four side surfaces 63. The building block 60 has a height h and to achieve the desired height, a number of blocks adding up to the correct height are stacked onto each other. A magnet 64, 65 is arranged in the top and bottom surface 61, 62. The bottom magnets 65 can be used to lock the building block to a metal workspace and also to lock the building blocks to each other when they are stacked on top of each other. Locking knobs 66 are arranged in each corner at the top surface 61 and corresponding locking recesses 67 are arranged at the bottom surface corners. When the building blocks 60 are stacked on top of each other, the locking knobs 66 fits into the locking recesses 67, thus locking the blocks in correct position with respect to each other.

For any type of building block there may be provided groups of blocks with a specified number of predetermined heights. There will be provided several building blocks with each of the predetermined heights so that any desired height of a stack can be achieved by combining the correct building blocks.

Figure 7 shows another embodiment of a building block 70. Similar to the building block of figure 6, this embodiment comprises a cubic building block with a bottom surface 72, a top surface 71 and four side surfaces 73. There may also be arranged magnets 74, 75 in top and bottom 71, 72 respectably. In this embodiment there are electric connection points 76, 77 in the top and bottom 71, 72 that are internally electrically connected together by conductors 78 in the block 70. When the blocks are stacked and interlocked, the connection points in the bottom of one block connects to the connection points in the top of the other, providing an electric connection. This makes it possible to drive power and signals through the building blocks. The power and signals can be used to operate the rebar fixing means arranged on top of each stack of building blocks.

It should be noted that even if the examples show building blocks that are cubic, other shapes can be used such as cylindrical, elongated with six sides or other suitable form.

Figure 8 illustrates a building block 80 with rebar fixing means. The rebar fixing means are in this embodiment a magnet 82, more specifically an electromagnet that can be switched on and off by means of electricity fed by the cable 81. In other embodiments, the electromagnet can be powered by means of a battery. The battery may be changeable, or it may be chargeable.

When the electromagnet is switched on, the rebar 88, which is made of metal, is attracted to the building block and fixed in place. The positioning is achieved by means of the shape of the building block 80. The building block comprises a cradle 84 into which the rebar 88 is placed. The cradle 84 is in this embodiment semi circular, but may have other shapes such as triangular, polygonal or other suitable shape that provides a stable bed for the rebar.

When the rebar construction is finalized, the magnets can be switched off and the rebars released from the rebar fixing means. The building block stacks can be disassembled and re-used for another rebar fixing structure.

Figure 9 illustrates a building block 90 with another embodiment of rebar fixing means 91. The rebar fixing means 91 comprises in this embodiment two movable fingers 91, 93 which are adapted to move laterally so that they move towards each other in an inwards movement to grip and fix a rebar and move away from each other in an outwards movement to release the rebar. The fingers are controlled by a motor, pneumatics or other means (not shown) which in turn is powered by a power source such as battery or cable as described above for figure 8.

Figure 10 illustrates a building block 100 with yet another embodiment of rebar fixing means. The rebar fixing means comprises in this embodiment a hook or a single finger 101. The hook 101 is shaped as an arc and is pivotably connected to the building block at a hinge 103. The far end of the hook 101 fits into a locking recess 109 which is complimentary arc shaped and comprises a locking means such as a latch, a magnet or any suitable locking means. The building block 101 comprises a cradle 104, similar to the cradle 84 of figure 8, where the rebar is positioned. The hook 101 rotates over the rebar until its end is secured into the locking recess 109. The locking of the hook 101 in the locking recess fixes the rebar in the correct position. The hook can be controlled by a motor, pneumatics or other means (not shown) which in turn is powered by a power source such as battery or cable as described above for figure 8. All the embodiments illustrated in figures 8-10 comprises features of the building blocks in figure 6 and 7, such as bottom magnets 82, 92, 102 for locking the building block to a metal workspace and/or to lock the building blocks to other building blocks when they are stacked on top of each other. Locking knobs of building blocks below in a stack fits into the corresponding locking recesses 87, 97, 107arranged at the bottom surface corners, thus locking the blocks in correct position with respect to each other.

Figure 11 shows the rebar fixing means of figure 9 in use. The fixing means can be arranged in any position to provide suitable fixing of the rebar according to the specific rebar fixing structure configuration.

The rebar fixing means of the figure 9 and 10, as well as other embodiments comprises a motor for moving the fmgers/hook 91, 93, 101. The motor can be connected to or comprise a signal processor for receiving and processing signals to control the movement of the fmgers/hook and thus fix or release the rebars. There may be provided dedicated building blocks for each orientation, or the building blocks can be adapted for use in several positions. Figure 1 lb shows a building block 110 with rebar fixing means 111 and two magnets 112, 113 for connecting to another building block. In figure 11a, the same building block is arranged at the top of two stacks 114, 115 in two different orientations.

The system may comprise means for wireless signal communication and the signal processor can be configured to receive and/or send wireless signals and control the rebar fixing means to fix or release. In other embodiments, the building blocks may comprise cable ducts for signal and/or power cables and they may comprise contact points where signals and/or power can be transferred. Example of contact points is described in figure 7 above, but there may be other suitable embodiments of contact points, such as in the locking knobs and recesses etc.

In one embodiment, each of the rebar fixing means’ signal processor have allocated an individual address. This enables an operator or control software to control the individual fixing means during the construction process.

As described above, the building blocks comprise a connecting mechanism for interlocking with another building block in order to provide a stack of building blocks where each block is securely connected to the block below and/or above itself. Figures 12 to 15 shows two examples of anchoring means that can be used as connecting mechanisms alone or in combination with other connecting mechanisms.

The anchoring means shown in figure 12 and 13 uses a foldable anchor 121 that is connected to a wire 122. The wire may be a flexible wire or a rigid wire/rod. The building blocks in this embodiment comprises through holes 123 which are aligned in the stack 120 of building blocks. The workspace 124 comprises holes which can be aligned with the holes in the stack 120. The anchor 121 and wire 122 is inserted into the holes all the way through the stack 120 and the workspace 124, whereafter it unfolds below the workspace.

The anchor 121 comprises an unfolding mechanism that causes the unfolding. The unfolding mechanism could be realized in its simplest form by gravity. As long as no force is holding the anchor folded, it unfolds by default.

Figure 12a shows the anchor 121 directly prior to insertion into the stack 120. In figure 12b the anchor 121 has passed through the stack 120 and has started unfolding, while in figure 12c the anchor is fully unfolded. In order to anchor the stack 120 to the workspace 124, the wire is pulled upwards through the stack by means of a tensioning mechanism such as a spring, motor etc. When the wire has been tensioned sufficiently, the anchor and wire hold the stack 120 firmly in place at the workspace 124.

Figure 13a and 13b shows the situation of figures 12a and 12d in perspective view. In figure 13b, the tension has been applied and the wire 122 has been fixed in place with the desired tension.

For disassembly, the anchor 121 has to be folded together and drawn up. The folding together can happen for example through a second wire, that when pulled folds the anchor together. Alternatively, the wire holding the anchor can be released on the top and fall down.

Figure 14 and 15 illustrates another example of anchoring means for anchoring a stack of building blocks. This embodiment uses a solid (non-foldable) anchor 141.

In this alternative, the anchor 141 is inserted from the top, and the tensioning wire 142 is inserted into and through the through hole in the center of the stack 140 of building blocks.

The wire 142 is then caught under the workspace and inserted into a tensioning mechanism. 143. Figure 14a to 14e illustrates the steps of this process.

Figure 15a and 15b shows the situation of figures 13a and 13c in perspective view.

The tensioning mechanism 143 can be mounted under the workspace. The wire may be flexible, and the tensioning mechanism can be arranged in other locations, if it benefits the operation of the system. The tension mechanism 143 may also be used in the embodiment shown in figure 12 and 13. Other tension mechanisms may for example be a manually operated winch with a handle that can or cannot be removed, a motorized winch, gravity by using heavy weights or a combination of the above.