PANEL CONNECTION DEVICE TECHNICAL FIELD

[0001] The present invention relates to a device for connecting building panels. BACKGROUND ART

[0002] Panels are routinely used in the building industry. In particular, it is common for buildings to be constructed from pre-cast concrete panels, which are cast and cured in a factory (off-site) then transported to the building site, or tilt-up concrete panels, which are cast and cured at the building site (on-site) and then moved (tilted) into position. As the basic process for casting and curing a pre-cast or a tilt-up concrete panel is essentially the same, any reference within this specification to a pre-cast concrete panel is also a reference to a tilt-up concrete panel.

[0003] There are a number of devices and methods available for connecting pre-cast concrete panels in situ. A common method for connecting pre-cast concrete panels is to use a welded connection. However, this option involves on-site welding and is therefore relatively expensive and also time-consuming. In addition, welded joints are often stronger than necessary for the required load and consequently have no give during extremes of temperature (hot or cold) or during earth movement (such as natural subsidence, or more extremely, during an earth tremor or earthquake). As an external joint, welded joints are also susceptible to damage, such as rust, or in the case of a fire, melting. One way of avoiding the problem of rust is to recess the joint into the panel and grout over the welded joint, however, this adds to the overall costs, including costs for labour, time and materials.

[0004] Alternatively, pre-cast concrete panels can be connected using a bolted angle connection. The use of bolted channel connectors for joining pre-cast concrete panels has also become popular in recent times. Whilst a relatively inexpensive solution for connected pre-cast concrete panels, it is an external connection, and therefore visible but not aesthetically pleasing. Importantly, it is not particularly useful in load-bearing situations.

[0005] European patent publication no. EP 0 558 344 Al discloses apparatus for joining precast concrete units. The apparatus comprises a series of spaced tubular members which are flush with the end of the concrete unit with which they are associated. The tubular members are cast within the concrete unit at the time the unit is formed. In addition to the tubular members, the apparatus comprises insert members having internal and external threads and guide members. The apparatus further requires the use of bolts through the guide members to join the pre-cast concrete units.

[0006] Another option for connecting pre-cast concrete panels is to use flexible wire loops which contained in a box-like structure attached inside or along the side edges of each panel. This connection method requires the use of a reinforcing bar which passes through the loops and the bar and loops are then fully embedded in grout.

[0007] Grout tubes are a commonly used option for connecting pre-cast concrete panels to footings, and are therefore located at the bottom edge of panels. Typically, the grout tubes are set in the panel at the time of casting such that when the panel is in place, the tube is positioned over a reinforcement bar protruding from the footing, and then a grouting mixture (commonly non-shrink, high strength cement-based grout) is poured through a filling hole on the panel. The design of grout tubes is such that they are suited only for use as vertical connectors, not for horizontal connection of pre-cast concrete panels.

[0008] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

SUMMARY OF INVENTION

[0009] The present invention is directed to a device for connecting building products, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

[0010] With the foregoing in view, the present invention in one form, resides broadly in a device for joining a first building panel to an adjacent second building panel, the device including a first housing portion to be cast within one of the first building panel or the second building panel during formation of the panel, a second housing portion to be cast within the other of the first building panel or the second building panel during formation of the panel, the first housing portion including an elongate connection element and a drive mechanism within the panel but accessible from outside the panel after formation of the panel to extend the elongate connection element relative to the first housing portion, and the second housing portion including a receiving portion for receiving a part of the elongate connection element when driven there into.

[0011] The device of the present invention can be used for joining a variety of products used in the building industry. Products which can be joined by the device of the present invention include panels, columns and beams. Typically, these products are made from concrete, due to its strength, durability and versatility. In particular, the use of pre-cast concrete panels and pre-cast concrete columns provides for a relatively quick and cost-effective method of construction. Thus, the device of the invention can be used to join a pre-cast concrete panel to a pre-cast concrete column. The device of the invention can also be used to join a pre-cast concrete panel to another pre-cast concrete panel. Therefore, in particularly preferred embodiments, the first and second building panels are pre-cast concrete panels.

[0012] The first and second building panels can be joined in any desired orientation. For example, the first and second building panels can be joined such that the panels are oriented horizontally. That is, the top edge of one building panel is adjacent to the bottom edge of the other building panel. Alternatively, the first and second building panels can be joined such that the panels are oriented vertically, whereby the side edge of one building panel is adjacent to the side edge of another building panel.

[0013] Pre-cast concrete panels can be cast on-site or off-site. The concrete is poured into formwork and allowed to cure to the required level of strength. For the present invention, a first housing portion is positioned within the formwork of a first building panel, and a second housing portion is positioned within the formwork of a second building panel, which in use, will be positioned adjacent to the first building panel. The first and second housing portions can be positioned in any suitable location within the formwork for the first and second building panels. For example, a first housing portion can be positioned in the formwork of a first building panel that is intended for use as a wall at an edge that will ultimately be a side edge of the first building panel. A second housing portion would then be positioned in the formwork of a second building panel that is intended to be adjacent to the first building panel at an edge that will ultimately abut the side edge of the first building panel where the first housing portion is positioned.

[0014] A building panel that will ultimately have adjacent building panels on both sides, that is, a central building panel, can be cast with a first housing portion on one side and a second housing portion on the opposite side. Alternatively, the central building panel can be cast with a first housing portion on one side and a further first housing portion on the opposite side. In this situation, the adjacent building panels would each require a second housing portion on the side that will ultimately abut the central building panel. Thus, each building panel can be cast with one or more housing portions, as long as the adjacent building panel has the appropriate housing portion to complement, so that when a pre-cast panel is placed in position, each first housing portion is paired with a second housing portion on an adjacent building panel. [0015] The first and second housing portions can be made from any suitable material. For ease of manufacture, and therefore to ensure the device of the present invention is price competitive, the first and second housing portions are preferably plastic. Any suitable process for the preparation of the first and second housing portions can be utilised. Preferably, the first and second housing portions are moulded plastic prepared by injection moulding.

[0016] The elongate connection element is preferably a cylindrically shaped element, such as a dowel pin. To provide strength to the connection between the building panels, preferably the elongate connection element is metal. Particularly preferably, the elongate connection element is steel.

[0017] Preferably, the elongate connection element is a steel rod which has surface irregularities. The surface irregularities can include any type of deformation to the surface of the steel rod, including transverse ridges or ribs. For example, the steel rod can be deformed reinforcing bar or can be a threaded steel rod. In embodiments where the steel rod is a threaded steel rod, the rod can be threaded along its entire length, or it can be threaded along a portion of its length. In those embodiments where the steel rod is threaded along only a portion of its length, the threaded portion is associated with the drive mechanism of the first housing portion, such that activation of the drive mechanism results in the steel rod being driven towards, and into, the second housing portion.

[0018] The elongate connection element is of a length such that it in use, it traverses a first housing portion in a first building panel and a second housing portion in an adjacent second building panel. During casting of a building panel comprising a first housing portion, the elongate connection element can be fully contained within the first housing portion, or the elongate connection element can be partially contained within the first housing portion, with a section of the elongate connection element protruding from the first housing portion.

[0019] The drive mechanism can be any suitable mechanism that acts upon the elongate connection element and causes it to extend relative to the first housing portion. For example, the drive mechanism can comprise one or more springs. The drive mechanism can be activated by any suitable means, dependent on the type of drive mechanism. For example, the drive mechanism can be activated by a source of compressed air, or a tool specific for the type of drive mechanism. Access to the drive mechanism to enable activation can be varied dependent on the type of drive mechanism. The drive mechanism can thus be accessed for activation via a hole on the surface of the building panel, or a hole or access point on a top edge, side edge or bottom edge of the panel. [0020] In a particularly preferred embodiment, the drive mechanism comprises at least one cog wheel which meshes with the threaded portion of the elongate connection element. Rotation of at least one cog wheel results in translation motion of the elongate connection element.

Rotation of the cog wheel can be effected via an access hole on the surface of the building panel formed during casting of the panel. A number of means for rotating an enclosed cog wheel are known. Preferably, the cog wheel has a central axis with a bore suitably shaped to accept and engage with a tool, which can be used to turn the cog wheel, and thus move the elongate connection element. In one embodiment, the cog wheel has a central axis with a hexagonally shaped bore into which a hex key can engage. In such an embodiment, a hex key can be inserted in the access hole of the building panel and turned, thereby effecting rotation of the cog wheel resulting in translation of the elongate connection element. In a particularly preferred embodiment, the cog wheel has a central axis with a square shaped bore into which a square key can engage. In this preferred embodiment, a square key can be inserted in the access hole of the building panel and turned, thereby effecting rotation of the cog wheel resulting in translation of the elongate connection element.

[0021] Optionally, translation of the elongate connection element is reversible. That is, the drive mechanism that results in translation of the elongate connection element so that it extends from the first housing portion into the second housing portion, can be reversed, so that the elongate connection element can be withdrawn from the second housing portion.

[0022] In an alternative aspect, the present invention provides a method of joining a first building panel to an adjacent second building panel, the method comprising casting a first housing portion within one of the first building panel or the second building panel during formation of the panel, casting a second housing portion within the other of the first building panel or the second building panel during formation of the panel, wherein the first housing portion includes an elongate connection element and a drive mechanism accessible from outside the panel after formation of the panel to extend the elongate connection element relative to the first housing portion, and wherein the second housing portion includes a receiving portion for receiving a part of the elongate connection element when driven there into, positioning the first building panel, positioning the second building panel adjacent to the first building panel, accessing the drive mechanism of the first housing portion and activating the drive mechanism to drive the elongate connection element towards and into the receiving portion of the second housing portion.

[0023] Following activation of the drive mechanism to drive the elongate connection element into the receiving portion of the second housing portion, any voids in the first and second housing portions can be filled with a packing material. The use of a packing material not only acts to secure the elongate connection element in a position bridging the first and second housing portions, but also adds to the strength of the join between the first and second building panels. The packing material can be any suitable material, such as concrete, a grouting mixture, mortar, asphalt or a resin. In particularly preferred embodiments, the packing material is concrete or a grouting mixture.

[0024] Preferably, the second housing portion comprises a liquid-impermeable barrier extending across the receiving portion. The liquid-impermeable barrier acts to contain the packing material and prevent excess packing material leaking from around the elongate connection element. The liquid-impermeable barrier can be made from any suitable material, and preferably, is made from a chemically non-reactive material. The liquid-impermeable barrier can thus be a foam-based seal that can be punctured by the elongate connection element, as the elongate connection element is driven into the second housing portion.

[0025] The first and second housing portions preferably each have an inlet through which packing material can be passed into any voids within the first and second housing portions once the building panels have been joined. The inlets are accessible from the outside of each panel.

[0026] The inlets are in fluid communication with the first and second housing portions. The inlets can therefore be on the surface of each panel adjacent to the first and second housing portions. Alternatively, the inlets can be on an edge of each panel. Thus, an inlet in fluid communication with a housing portion, could be present on an upper edge of a panel, or an inlet could be present on a side edge of a panel. Advantageously, these alternative positions for the inlets leave the surface finish of each panel intact, without the need to fill and cover up any inlets.

[0027] Preferably, the first and second housing further comprise overflow holes which egress to the outside of the panel. The overflow holes provide a means for air in the voids to exit the first and second housing portions as the packing material is passed into the voids, so that no air remains in the housing portions. Any air remaining would result in a weaker join.

[0028] Preferably, the overflow holes egress to the region between the joined panels. This provides a visual cue that no air remains in the housings, but does not result in any excess packing material which flows through the overflow holes spoiling the surface faces of the building panels. [0029] In an alternative embodiment, only the first housing portion has an inlet through which packing material can be passed into any voids within the first and second housing portions once the building panels have been joined. The inlet is accessible from the outside of a panel. The inlet can be on the surface of a panel adjacent to the first housing portion. Alternatively, the inlet can be on an upper edge, or a side edge of the panel.

[0030] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

BRIEF DESCRIPTION OF DRAWINGS

[0031] Various embodiments of the invention will be described with reference to the following Figures, in which:

[0032] Figure 1 shows internal and external features of first and second housing portions of a device according to one embodiment of the present invention;

[0033] Figure 2 shows internal and external features of first and second housing portions of a device according to the embodiment of Figure 1 , with the elongate connection element positioned in the receiving portion of the second housing portion;

[0034] Figure 3 shows formwork with first and second housing portions of the device of Figures 1 and 2 held in place;

[0035] Figure 4 shows a second housing portion of the device of Figures 1 and 2;

[0036] Figure 5 shows the second housing portion of Figure 4 held in place in formwork with reinforcing bars;

[0037] Figure 6 shows the formwork of Figure 5 in the process of filling with concrete;

[0038] Figure 7 shows the formwork of Figure 6 filled with concrete;

[0039] Figure 8 shows the completed panel of Figure 7 with the second housing portion of Figure 4 cast within the panel;

[0040] Figure 9 shows the access hole for a first housing portion of the device of Figures 1 and 2 which has been cast within a panel;

[0041] Figure 10 illustrates a square key inserted into the access hole of Figure 9; [0042] Figure 11 shows two panels which have been joined using the first and second housing portions of the device of Figures 1 and 2;

[0043] Figure 12 shows the voids of a housing portion of a device of the present invention being filled with packing material;

[0044] Figure 13 shows packing material from the overflow holes; and

[0045] Figure 14 shows panels that have been joined using a device according to an embodiment of the present invention.

[0046] Preferred features, embodiments and variations of the invention may be discerned from the following Description which provides sufficient information for those skilled in the art to perform the invention. The Description is not to be regarded as limiting the scope of the preceding Summary of Invention in any way.

DESCRIPTION OF EMBODIMENTS

[0047] Similar features are numbered similarly throughout the Figures.

[0048] Referring firstly to Figure 1, there is shown an exploded image of a device according to one embodiment of the present invention. Internal and external features of a first housing portion 10 and a second housing portion 12 can be seen. Specifically, the first housing portion 10 comprises an upper casing 10a and a lower casing 10b. Within the lower casing 10b of the first housing portion 10, is positioned a threaded steel rod 14. The threaded steel rod 14 is associated with a drive gear 18 such that the drive gear 18 engages with the thread of the threaded steel rod 14. The drive gear 18 has a square shaped bore which can be accessed from the exterior of the panel when the device is in situ.

[0049] The second housing portion 12 comprising an upper casing 12a and a lower casing 12b. The second housing portion 12 has a foam seal 20 which the threaded steel rod 14 will break through to enter the receiving portion 22 of the second housing portion 12. The second housing portion 12 has an inlet 24 through which packing material can be passed to fill any voids within the first and second housing portions 10, 12 when the device is in situ. Excess packing material exits the device through overflow hole 26.

[0050] Internal and external features of first and second housing portions 10, 12 of a device according to the embodiment of Figure 1, with the threaded steel rod 14 positioned in the receiving portion 22 of the second housing portion 12 are shown in Figure 2. The device is shown in an exploded format so that the features can be better seen. Specifically, there is shown a first housing portion having an upper casing 10a and a lower casing 10b. Within the lower casing 10b is positioned a threaded steel rod 14. The threaded steel rod 14 is associated with a drive gear 18 such that the drive gear 18 engages with the thread of the threaded steel rod 14. The drive gear 18 has a square shaped bore which can be accessed from the exterior of the panel when the device is in situ. A square key 28 is positioned within the bore of the drive gear 18 and has been turned such that the threaded steel rod 14 has punctured the foam seal 20 of the second housing portion lower casing 12b and entered the receiving portion 22.

[0051] Figure 3 shows formwork 30 with first and second housing portions 10, 12 of the device of Figures 1 and 2 held in place, prior to casting a concrete panel.

[0052] A second housing portion 12 of the device of Figures 1 and 2 is shown in Figure 4. The second housing portion 12 is fitted with double-sided tape 32 to hold it in position in the formwork prior to casting a concrete panel.

[0053] Figure 5 shows a second housing portion 12 held in place in formwork with reinforcing bars, prior to casting a concrete panel. The second housing portion 12 is positioned against the edge of the formwork, so that it will be against the edge of the concrete panel.

[0054] In Figure 6, there is shown formwork for the casting of a concrete panel, in the process of filling the formwork with concrete. A second housing portion 12 of a device according to the present invention is positioned against an edge of the formwork.

[0055] Figure 7 shows the formwork of Figure 6 filled with concrete. An inlet 24 for filling voids within the device can be seen on the surface of the concrete.

[0056] A cast concrete panel 34 with a second housing portion 12 according to an embodiment of the invention is shown in Figure 8. The second housing portion 12 is positioned on the edge of the concrete panel 34, such that the foam seal 20 is accessible to an elongate connection element of a first housing portion of a second concrete panel.

[0057] An access hole 36 through which a square key can be inserted for operating the drive mechanism of a first housing portion which has been cast within a concrete panel 34 is shown in Figure 9. The first housing portion was cast within the panel 34 with a plug 38, to prevent concrete entering the first housing portion during casting of the panel 34. Once the panel 34 is cured and ready for use, the plug 38 can be removed to enable access to the drive mechanism for joining the concrete panel 34 to another panel. [0058] Figure 10 illustrates a square key 28 inserted into the access hole 36 of a concrete panel 34. Turning the square key 28 activates the drive mechanism of the first housing portion within the concrete panel 34.

[0059] Figure 11 shows two panels 34, 34a which have been joined using a device according to the present invention. A first housing portion has been cast in panel 34 and a second housing portion has been cast in panel 34a. An access hole 36 on panel 34 allowed for access to the drive mechanism of the first housing portion to drive the threaded steel rod 14 into the receiving portion of a second housing portion cast in panel 34a.

[0060] Figure 12 shows the voids of a device of the present invention being filled with grout. Two panels 34, 34a have been joined using a device according to the present invention. A grout gun 40 is positioned in the inlet 24 of the second housing portion to enable any voids within the first and second housing portions to be filled with grout.

[0061 ] Detail of the join between two concrete panels 34, 34a which have been joined is shown in Figure 13. The threaded steel rod 14 joining the panels 34, 34a can be seen between the panels. Overflow grout 42 from the overflow hole 26 is also visible, as a visual indicator that the voids within the first and second housing portions have been filled.

[0062] Figure 14 shows panels 34, 34a, 34b that have been joined using a device according to an embodiment of the present invention (marked with dashed lines 44). Temporary clamps 46 hold the panels in place until the grout sets.

[0063] It can thus be seen that the present invention provides a device that enables building panels to be joined efficiently, rapidly and safely. Advantageously, the device is cast within the panels and therefore does not detract from the aesthetics of the panels.

[0064] Reference throughout this specification to One embodiment' or 'an embodiment' means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases 'in one embodiment' or 'in an embodiment' in various places throughout this specification are not necessarily all referring to the same embodiment.

Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[0065] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.