NZ738091B2 - Stackable wall spacer for supporting reinforcement in concrete constructions - Google Patents

Abstract

Stackable wall spacer adapted for automated distribution using a feeder device and adapted to support a reinforcement grid, where the wall spacer comprises a plurality of leg sections each having a lower foot adapted to be placed on a mould surface for the concrete, where a plurality of wall spacers can be stacked in each other with the feet of one wall spacer extending into corresponding voids of a subsequent wall spacer, where the side wall of a leg section is parallel with the side wall of a leg section of a subsequent wall spacer. The advantage of the invention is that the wall spacers can be stacked in a space saving manner in each other, which allows a cost-efficient storage and transportation of wall spacers. The invention further allows for wall spacers that can be distributed by using a hand-held or automatic feeder device. Further, a reinforcement grid can be supported by a wall spacer regardless of the position of the spacer.

Description

STACKABLE WALL SPACER FOR SUPPORTING REINFORCEMENT IN CONCRETE CONSTRUCTIONS TECHNICAL FIELD The present invention relates to a stackable wall spacer adapted to be used for supporting reinforcement grids in concrete constructions. The stackable spacer may be adapted for automated distribution using a feeder device. The size and shape of the spacer is such that it will give reliable support to the reinforcement grid even if the spacers are placed randomly on the mould or form surface. The spacers can be distributed manually, by the use of a hand-held feeder device or by the use of a semi- automatic or automatic feeder device. Due to the fact that the positioning of the spacers is not critical, a cost-effective spacer is provided.

BACKGROUND ART Concrete constructions are normally provided with some kind of reinforcement to increase the strength and to prevent cracking. The reinforcement can be single reinforcement bars (rebars), reinforcement grids/meshes or different kinds of fibres or other. Most common are reinforcement grids/meshes made from reinforcement bars of steel when larger areas are to be covered. For smaller areas or as a complement to the grids, single reinforcement steel bars are often used.

To achieve the required properties in a construction, the reinforcement is placed at different heights. This height creates a concrete cover around the reinforcement in the finished construction. Reinforcement spacers are used to simplify the work of positioning the reinforcement at the prescribed height and to maintain it there through the process until the concrete has burned. The type of spacer used is influenced from e.g. regulations, demands from the users, the surrounding environment, natural resources or aesthetic opinions.

The concrete cover is defined as the smallest distance between the reinforcement material and the concrete surface of the completed construction. A concrete cover which differs from the requirements can negatively affect the strength and life cycle of a construction. The requirements on a concrete cover can be set by national regulations and may vary depending on type of construction and on the surrounding environment. One purpose of the concrete cover is to prevent moisture to reach the reinforcement steel, in order to avoid the negative effects corrosion has on the construction. Corrosion will, through its expansion, slowly break apart the nearby concrete, which causes more moisture to reach the steel which in turn accelerates the corrosion process. Over time this will weakens the construction strength.

To provide support for the reinforcement, reinforcement spacers are used.

These are often made from plastic and are designed to facilitate that the concrete fully embraces the reinforcement and the spacers. Air pockets in the final construction are not desirable and should be avoided. Depending on the shape of the spacer, it must be provided with some kind of apertures in order to provide escape ways for air to disappear when concrete is poured upon them.

Reinforcement spacers are made from different materials. Most common are spacers made from plastic, but steel, concrete and other materials are also used. Plastic spacers have several advantages compared to other materials, such as ease of handling, low weight and generally low price, the manufacturing process is fast and spacers can easily be formed to a desired shape. Concrete spacers can be used in most constructions.

However, the material makes them heavy and the design makes them more complicated to work with. They are primarily used when plastic is not allowed. Steel spacers are primarily used as spacers inside constructions, e.g. between two layers of reinforcement grids. Steel spacers are seldom used as an outer spacer closest to the outer concrete surface as this may cause corrosion problems.

Depending on the field of application, reinforcement spacers are divided into two main groups, foundation spacers and wall spacers. Foundation spacers are primarily used for positioning reinforcement in foundations/ ground plates, while wall spacers are primarily used for positioning reinforcement in walls, floors, joists and ceilings. The main difference is the type of underlying surfaces that they are intended to be used on.

Foundation spacers are designed to be used when the formwork surface is classified as soft and/or uneven, such as EPS (extruded polystyrene), a bedding of coarse sand, gravel, grit or other free-draining material or ground. The bearing surface of the spacer towards the ground has a relatively large area and often a large diameter to aid the spacer to stand stable on the ground and not to dig in to the ground/EPS or to tip over.

Since foundation spacers primarily are used for ground plates and foundations, the spacer bearing surface will point downward and will not be visible. Foundation spacers thus have no aesthetic significance. It is important that the base plate area of the foundation spacer is large enough not to punch the underlying surface and that it minimizes the risk of the foundation spacer tipping over.

Wall spacers are often designed with thin legs and/or small feet. The formwork surface is generally hard and even, being a mould, which helps to prevent the spacer to tip over or to cut through the surface. When the formwork is removed, the spacer feet are made visible. At a surface not further processed, these feet will show in the concrete surface, especially if they are large, which is not desirable. Therefore wall spacers are designed with minimal feet and are also nearly always coloured like the surrounding concrete. Low visibility is important.

Wall spacers are divided into different subgroups due to differences in design and the way they are used. One type is referred to as linear spacers. They are long and narrow. They support the reinforcement anywhere on its support area lengthwise and no exact positioning is thus required. Due to their length, up to 2 meters, they shorten the working time of placing the spacers. Another subgroup comprises small individual wall spacers of different designs. The size is most often a few centimetres in each direction, with different shapes that may e.g. be flat or circular. These are all manually fixed to the reinforcement. Another subgroup comprises circular or square grid spacers which are larger than a single mesh in a reinforcement grid. Like linear spacers, no exact positioning of the spacers is required and they are often used within the precast industry. Another subgroup comprises automated disc-shaped "wheel" spacers. They are often used in the precast industry, in fully automated production lines where the spacers are attached to rebars by an automatized mounting device. Also handheld mounting device can be used.

AU 2006100538 describes a linear wall spacer, having small feet adapted for the use as a wall spacer. A specific base segment can be attached to the feet, such that the spacer can be used as a foundation spacer. US 4942714 describes a linear wall spacer. US 2005005564 describes a stackable foundation spacer having an upper receiving section for fixedly retaining of a wire mesh or single reinforcement bars.

DE 2821078 describes a circular grid spacer for walls adapted for producing prefabricated modules, where the spacer can be placed randomly on the mould. With a diameter larger than a single square in a reinforcement grid, the spacer will always give support regardless of its position. DE 2809430 also describes a similar wall spacer that can be positioned randomly.

DE 7408515 shows different shapes of disc-shaped "wheel" spacers adapted for automated assembly of spacers on rebars, and also shows how the spacers are mounted to the rebars.

DE 4218573 describes a disc-shaped "wheel" spacer and equipment for automatically attach such spacers on reinforcement bars. Each spacer and the rebar must be in an exact position before any assembling is possible.

US 3830032 describes a modular spacer which is adapted to be attached to a reinforcement by hook arms. Two or more spacers can be placed on each other in order to provide spacers of different heights. Feet portions of a spacer can be inserted into corresponding holes of another spacer such that the spacers can be nested together. US 20080028718, US 4060954 and US 6089522 also describe modular spacers where two or more parts can be stacked on each other in order to provide spacers with different heights.

All these spacers are transported separately and are only stacked when in use. The stacked parts are further adapted to give a good hold, such that the parts do not separate easily.

There is thus room for an improved wall spacer.

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents or such sources of information is not to be construed as an admission that such documents or such sources of information, in any jurisdiction, are prior art or form part of the common general knowledge in the art.

DISCLOSURE OF INVENTION An object of the invention is therefore to provide an improved stackable wall spacer for supporting a reinforcement grid. A further object of the invention is to provide an improved stackable wall spacer which is adapted for automated distribution. An additional or alternative object of the invention is to at least provide the public with a useful choice.

The solution to the problem according to the invention is described in the claim 1 regarding the wall spacer. The other claims contain advantageous embodiments and further developments of the wall spacer.

In accordance with a first aspect, there is provided a stackable wall spacer adapted to be distributed randomly on a mould surface for support of a reinforcement grid, the wall spacer comprising: a central opening having a rim configured to interact with a release mechanism operating outwards from the body of a feeder device to be used for distribution of the wall spacer; and a circumferential body section having: an upper support surface which is flat and is situated in one plane and is adapted to support the reinforcement grid, at least one side wall spaced from the rim and extending between the upper support surface and a base of the body section, the base lying in another plane parallel to and spaced apart from the plane of the upper support surface, and a plurality of leg sections each having side walls spaced from the rim and a foot adapted to be placed on a mould surface for the concrete, wherein: an outer shape of the circumferential body section is larger than a mesh in the reinforcement grid that is to be supported; each of the side walls of each leg section defines a continuous surface that extends from the upper support surface to the foot, the continuous surface being inclined with respect to a vertical direction; and each leg section is provided with a void adapted to house a leg section of another wall spacer, such that a plurality of wall spacers can be stacked in each other with the leg sections of one wall spacer extending into the corresponding voids of a subsequent wall spacer, such that each of the side walls of each leg section is parallel with the side wall of each leg section of the subsequent wall spacer. In accordance with a second aspect, there is provided a stackable wall spacer adapted to be distributed randomly on a mould surface for support of a reinforcement grid, the wall spacer comprising: a central opening having a rim configured to interact with a release mechanism operating outwards from the body of a feeder device to be used for distribution of the wall spacer; and a circumferential body section having: an upper support surface which is flat and is situated in one plane and is adapted to support the reinforcement grid, a base lying in another plane parallel to and spaced apart from the plane of the upper support surface, and a plurality of leg sections each having side walls spaced from the rim and a foot adapted to be placed on a mould surface for the concrete, wherein: the outer shape of the circumferential body section is larger than a mesh in the reinforcement grid that is to be supported; the foot of each of the plurality of leg sections lies in a plane parallel to and spaced apart from the planes of the upper support surface and the base, such that the plane of the base is intermediate the planes of the upper support surface and the foot; each of the side walls of each leg section defines a continuous surface that extends from the upper support surface to the foot, the continuous surface being inclined with respect to a vertical direction; and each leg section is provided with a void adapted to house a leg section of another wall spacer, such that a plurality of wall spacers can be stacked in each other with the leg sections of one wall spacer extending into the corresponding voids of a subsequent wall spacer, such that each of the side walls of each leg section is parallel with the side wall of each leg section of the subsequent wall spacer.

In a stackable wall spacer adapted to support a reinforcement grid, where the wall spacer comprises a circumferential body section having an upper support surface adapted to support the reinforcement grid, and a plurality of leg sections each having a lower foot adapted to be placed on a mould surface for the concrete, where the outer shape of the circumferential body section is larger than a mesh in the reinforcement grid that is to be supported, the object of the invention is achieved in that each side wall (19) of a leg section (4) is inclined with respect to a vertical direction and that a leg section is provided with a void at an upper portion of a leg section, where the void is adapted to house a leg section of another wall spacer, such that a plurality of wall spacers can be stacked in each other with the feet sections of one wall spacer extending into the corresponding voids of a subsequent wall spacer, such that the side wall of a leg section is parallel with the side wall of a leg section of a subsequent wall spacer.

By this first embodiment of the wall spacer according to the invention, a wall spacer that can be stacked in a space efficient manner is provided.

The wall spacer is intended to be used to support reinforcement grids in concrete constructions when producing walls, floors, joists or ceilings using a mould or form. The size of the wall spacer is designed such that the wall spacer will always be able to support a reinforcement grid, i.e. the wall spacer will not be able to pass through the reinforcement grid. The shape of the wall spacer can be selected freely, as long as the outer dimensions of the upper support surface is larger than a mesh of the reinforcement grid in at least one direction. For a circular wall spacer, the diameter of the wall spacer must be larger than the width of a quadratic mesh in the reinforcement grid. For a quadratic wall spacer, a side wall of the wall spacer must be longer than the width of a quadratic mesh in the reinforcement grid. For a wall spacer having another shape, or for a reinforcement grid having rectangular meshes, the smallest width of the wall spacer in any direction must be wider than the smallest dimension of the mesh. In this way, the wall spacer will be able to support the reinforcement grid regardless of the relative position between the wall spacer and the reinforcement grid.

In order to be able to stack the wall spacers in each other with the same orientation, the leg sections must have inclined side walls with respect to a vertical direction and must be provided with a void, such that a leg section of one wall spacer can extend into the void of another wall spacer. When a first wall spacer is stacked with a second wall spacer, the side wall of a leg section of the first wall spacer will be parallel with a side wall of a corresponding leg section of the second wall spacer. Depending on the height of a wall spacer, i.e. on the length of a leg section, the side wall of a leg section of the first wall spacer will also be parallel with a side wall of a third stacked wall spacer. The inclination of a side wall of a leg section is here compared to a vertical direction. The wall spacer is intended to be used on horizontal surfaces, and the vertical direction is a direction perpendicular to the horizontal plane when the wall spacer is used.

The inclination of a side wall of a leg section is e.g. adapted to the height of the wall spacer and the thickness of a side wall, and is preferably in the range between 3 to 25 degrees. With a smaller inclination, several wall spacers cannot be stacked in each other, and with a greater inclination, the stability of the wall spacer and the strength of the leg sections are not optimal.

It is important that at least a part of a leg section extends into the void of a subsequent wall spacer, such that the side walls of the leg sections are parallel. In this way, the orientation of the wall spacers will be well defined which makes a stack of wall spacers easy to handle. A leg section of one wall spacer preferably extends into the void of a subsequent wall spacer with at least 30% of the height of the wall spacer, and may extend into the void of a subsequent wall spacer with at least 50% or more of the height, depending on the height of a wall spacer. The height of a wall spacer is the distance between the underside of a foot to the upper support surface.

Due to the size and shape of a wall spacer, the wall spacers can easily be embraced by concrete and they can be positioned randomly and can still support the reinforcement grid. Since the positioning of the spacers is not critical, the distribution of spacers can be made in a time-saving manner e.g. using a feeder device. Further, the wall spacers must not be attached to a reinforcement grid, which also save time. The shape of the wall spacer allows the spacers to be stacked in each other, which saves space during transportation and storage. Both manual and automated handling of the spacers is also facilitated.

In an advantageous development of the invention, the wall spacer comprises a central opening which is adapted to be used for an automated distribution of wall spacers. The central opening allows a stack of wall spacers to be inserted onto a hand-held feeder device through the central opening, where the feeder device comprises an elongated body. The wall spacers can be released one by one by operating a release mechanism in the feeder device. The feeder device operates outwards from the body of the feeder device, such that the feeder device holds and supports the wall spacers at a rim of the central opening. The rim of the central opening is preferably interconnected with the body section through a plurality of vertical connection walls. The use of connection walls provides an open wall spacer, which allows concrete to fill and surround the wall spacer.

In an advantageous development of the invention, the body section of the wall spacer comprises an outer side wall extending around the outer circumference of the wall spacer. In this way, the strength and the stability of the wall spacer is improved. The outer side wall is preferably provided with an outwards extending rim, which further improves the stability and the strength of the wall spacer, and by which the number of possible contact positions for the reinforcement grid is increased. The body section may also comprise an inner wall, preferably arranged adjacent the outer side wall. The outer and inner side walls are preferably interconnected by a plurality of vertical reinforcement walls, which connects the outer and inner walls to each other. In this way, the stability of the wall spacer is increased, and the reinforcement walls obviate the need for a bottom between the outer and inner side walls. In this way, the filling of concrete in and around the wall spacer is improved.

In an advantageous development of the invention, the outer shape of the wall spacer is quadratic. By using a symmetric shape, the handling of the wall spacer is simplified.

In an advantageous development of the invention, the outer shape of the wall spacer comprises three parts having a dividing angle of 120 degrees.

With such a shape, the stability of the wall spacer is improved. Further, the amount of material required for the wall spacer is reduced.

In an advantageous development of the invention, a leg section is circular and conical. In this way, the leg of one wall spacer will fit inside a corresponding leg of another wall spacer. In this way, a plurality of wall spacers can be stacked where the side walls of corresponding leg sections are parallel. Since each leg extends into a corresponding leg of another wall spacer, all wall spacers will be stacked with the same orientation. This simplifies the transport and storage of the wall spacers, and simplifies the distribution of wall spacers using a feeder device. It is also possible that a leg section comprises at least two perpendicular straight walls. The straight walls are also inclined with respect to a vertical direction, such that a leg section of a wall spacer can extend into a corresponding leg section of another wall spacer when the wall spacers are stacked in each other. The side walls of corresponding leg sections will be parallel and are arranged next to each other, such that the outer side wall of a wall spacer bears on or is very close to the inner side wall of a subsequent wall spacer. If ridges are used to define the vertical spacing of stacked wall spacers, the side walls may not bear on each other completely, but will be very close to each other, and the side walls of some leg sections may bear on each other. The advantage of using ridges is that the wall spacers will not "stick" to each other. This will also be influenced by the inclination angle of the side wall and the side wall thickness.

In an advantageous development of the invention, the wall spacer comprises a plurality of ridges arranged on the outer and/or inner side wall adapted to bear on the upper support surface of another wall spacer when several wall spacers are stacked. In this way, the wall spacers will not stick to each other when they are stacked, such that they can easily be separated one by one when they are distributed by a feeder device.

Further, a well-defined vertical interval for the stacked spacers is obtained.

A well-defined vertical interval between stacked wall spacers is important, and is preferably between 8-30 mm.

In an advantageous development of the invention, the wall spacer is further provided with a number of upward protruding pins, adapted to prevent a wall spacer from being dispositioned by the concrete when a large quantity of concrete is poured into a mould. With the protruding pins, the wall spacer will stay in the selected position. A recess is preferably arranged in the outer side wall of the body section below a pin, such that the pin can extend into a recess when two wall spacers are stacked in each other.

BRIEF DESCRIPTION OF DRAWINGS The invention will be described in greater detail in the following, with reference to the embodiments that are shown in the attached drawings, in which Fig. 1 shows a first embodiment of a wall spacer according to the invention, Fig. 2 shows a development of a wall spacer according to the invention, Fig. 3 shows another development of a wall spacer according to the invention, Fig. 4 shows a plurality of wall spacers according to the invention supporting a reinforcement grid, Fig. 5 shows a stack of wall spacers according to the invention, and Fig. 6 shows a cross-section of a stack of wall spacers according to the invention.

MODES FOR CARRYING OUT THE INVENTION The embodiments of the invention with further developments described in the following are to be regarded only as examples and are in no way to limit the scope of the protection provided by the

Claims (17)

1. A stackable wall spacer adapted to be distributed randomly on a mould surface for support of a reinforcement grid, the wall spacer comprising: a central opening having a rim configured to interact with a release 5 mechanism operating outwards from the body of a feeder device to be used for distribution of the wall spacer; and a circumferential body section having: an upper support surface which is flat and is situated in one plane and is adapted to support the reinforcement grid, at least one side wall spaced from the rim and extending between the upper support surface 10 and a base of the body section, the base lying in another plane parallel to and spaced apart from the plane of the upper support surface, and a plurality of leg sections each having side walls spaced from the rim and a foot adapted to be placed on a mould surface for the concrete, wherein: an outer shape of the circumferential body section is larger than a mesh in 15 the reinforcement grid that is to be supported; each of the side walls of each leg section defines a continuous surface that extends from the upper support surface to the foot, the continuous surface being inclined with respect to a vertical direction; and each leg section is provided with a void adapted to house a leg section of another wall spacer, such that a plurality 20 of wall spacers can be stacked in each other with the leg sections of one wall spacer extending into the corresponding voids of a subsequent wall spacer, such that each of the side walls of each leg section is parallel with the side wall of each leg section of the subsequent wall spacer.

2. A stackable wall spacer according to claim 1, wherein a leg section 25 extends into the void of a subsequent wall spacer with at least 30% of the height of the wall spacer.

3. A stackable wall spacer according to claim 1, wherein the side walls of each of the plurality of leg sections is inclined with an angle between 3 and 25 degrees in relation to the vertical direction. 30

4. A stackable wall spacer according to claim 1, wherein the at least one side wall of the body section comprises an outer wall extending along the outer circumference of the wall spacer.

5. A stackable wall spacer according to claim 4, wherein the at least one side wall of the body section comprises an inner wall arranged between 35 the outer wall and the central opening.

6. A stackable wall spacer according to claim 5, wherein the inner wall and the outer wall are interconnected by reinforcement walls.

7. A stackable wall spacer according to claim 1, wherein the outer shape of the wall spacer is quadratic. 25

8. A stackable wall spacer according to claim 1, wherein the outer shape of the wall spacer is circular.

9. A stackable wall spacer according to claim 1, wherein the outer shape of the wall spacer comprises three parts having a dividing angle of 120 5 degrees.

10. A stackable wall spacer according to claim 1, wherein each of the plurality of leg sections is circular and conical.

11. A stackable wall spacer according to claim 1, wherein each of the plurality of leg sections comprises at least two straight walls. 10

12. A stackable wall spacer according to claim 1, wherein each of the plurality of leg sections comprises a plurality of feet.

13. A stackable wall spacer according to claim 1, wherein the rim is interconnected with the body section through connection walls.

14. A stackable wall spacer according to claim 1, wherein: the wall spacer 15 comprises a plurality of ridges arranged at an upper portion of the leg sections; and a ridge is adapted to bear on the upper support surface of another wall spacer when several wall spacers are stacked in each other.

15. A stackable wall spacer according to claim 1, wherein the wall spacer comprises a plurality of upward protruding pins arranged at the upper 20 support surface.

16. A stackable wall spacer adapted to be distributed randomly on a mould surface for support of a reinforcement grid, the wall spacer comprising: a central opening having a rim configured to interact with a release mechanism operating outwards from the body of a feeder device to be 25 used for distribution of the wall spacer; and a circumferential body section having: an upper support surface which is flat and is situated in one plane and is adapted to support the reinforcement grid, a base lying in another plane parallel to and spaced apart from the plane of the upper support surface, and a plurality of leg sections each having side walls spaced from 30 the rim and a foot adapted to be placed on a mould surface for the concrete, wherein: the outer shape of the circumferential body section is larger than a mesh in the reinforcement grid that is to be supported; the foot of each of the plurality of leg sections lies in a plane parallel to and spaced apart from the planes of the upper support surface and the base, 35 such that the plane of the base is intermediate the planes of the upper support surface and the foot; each of the side walls of each leg section defines a continuous surface that extends from the upper support surface to the foot, the continuous surface being inclined with respect to a vertical 26 direction; and each leg section is provided with a void adapted to house a leg section of another wall spacer, such that a plurality of wall spacers can be stacked in each other with the leg sections of one wall spacer extending into the corresponding voids of a subsequent wall spacer, such 5 that each of the side walls of each leg section is parallel with the side wall of each leg section of the subsequent wall spacer.

17. A stackable wall spacer according to claim 1, substantially as herein described with reference to any embodiment disclosed