NZ336490A - Corner connector and stepped aperture for concrete panels or tilt slabs, and void former for such connector - Google Patents

Abstract

A corner connection for use in a tilt-up concrete panel construction has a stepped void former which can be cast into one panel 15 adjacent an edge thereof, which when physically removed from the panel will leave a stepped aperture 16, providing an elongate slot 18 for the reception and adjustment of a threaded bolt 31. An adjacent panel 10 is provided with one or more threaded sockets 12 cast into an edge face 11 of the panel 10 so that the two panel can be abutted together and secured by a concealed bolt 31. A rectangular spacer washer 52A with an off-set hole 50A is provided between the two panels to allow for a joint space 35 to be filled with a suitable sealant.

Description

Patents Form # 5 new zealand Patents Act 1953 COMPLETE SPECIFICATION AFTER PROVISIONAL # : 336490/504174/504901 DATED : 29 June 1999, 28 April 2000, 02 June 2000 TITLE • Corner Connector I, HOLLINGS, Clegg James Address 15b Tower Hill, Whangaparaoa, New Zealand Nationality: A New Zealand citizen do hereby declare the invention for which I pray that a patent may be granted to me and the method by which it is to be performed, to be particularly described in and by the following statement • -1 - •; .■ > r t i n ii >s | 1 3 jI l . J PF05 JWp FEE CODE 1050 | _ _ _ _ , , _ _ ? | t FIELD The invention relates to building constructions, particularly building constructions involving tilt-up panels where two walls are to meet at right angles.

BACKGROUND Where buildings are constructed from cast concrete panels, typically of the tilt-up panel variety, the walls need to be connected together at right angles. In the case of the external walls various attempts have been made to provide corner connections, but these invariably make use of exposed metal brackets, which intrude on the interior space of the building or a panel needs to be shaped in a particular way to enable the metal bracket to be covered over 10 after attachment of the walls at right angles to one another.

OBJECT It is an object of this invention to provide an improved connection system for buildings, or one which will at least provide the public with a useful choice.

STATEMENT OF INVENTION In one aspect, the invention provides a method of connecting building panels to one another wherein an edge face of a first panel is abutted against the main face of a second panel, and wherein the first panel has one or more threaded sockets embedded in or along said edge face thereof, with the exposed ends of the threaded sockets facing towards the main face of the second panel, and the second panel is provided with at least one stepped aperture passing 20 through and aligned with one of said sockets in the first panel, and a threaded fastener passing there-through the second panel into engagement with the threaded socket to secure the second panel to the edge face of the first panel.

Preferably the building panels are concrete panels.

More preferably the aperture in the second panel is produced by casting the concrete panel 25 with one or more void formers positioned in the panel during the casting of the concrete, so that the one or more void formers can be removed once the concrete has set. More preferably T848ISP1 600/JP/ld 1 Q ' ' I J ^^4- L., _J pcrmypn these void formers are removed once the concrete has hardened or has cured for seven days or more. Preferably the void formers are physically removed, and it is thus preferred that the void formers have a slightly tapered shape to assist in physical ejection from the panel once it has hardened Preferably the aperture in the second panel is in the form of a first cavity and a second cavity, wherein the first cavity is larger than the second cavity to retain a washer, or the head of a bolt or the like.

Preferably the second cavity is in the form of an elongate slot capable of allowing a fastener such as a bolt to be moved up or down within the slot in order to assist in alignment of the 10 bolt with a threaded socket in the first panel.

In another aspect, the invention provides a void former for use in the method of this invention, said void former having a first member and a second member protruding therefrom, wherein said first member is a substantially box like shape, having a first face at substantially right angles to the central axis of the second member, and wherein the second 15 member is a substantially oblong shape having a minor axis approximately equivalent to the diameter of the bolt or the like to be used in the aperture once formed in the panel, and a major axis which is greater than a minor axis to allow movement of the bolt within the aperture, so formed to assist in aligning the bolt with a threaded socket in another panel.

Preferably the first member and the second member are tapered slightly to assist in removal 20 of the void former from a concrete panel once cast. More preferably the second member has a cross section which is approximately oval, preferably having a pair of straight sides, and preferably having semi-circular ends so that a cylindrical bolt or the like can be moved fully within the slot defined by the aperture after removal of the void former.

In another aspect, the invention provides a building in which at least two of the panels have 25 been connected together by the method of this invention.

More preferably the building is constructed using a tilt-up panel technique, with the tilt-up panels being used to form the walls of the building.

Preferably two such tilt-up panels are connected together by the method of this invention. »h . > l , ; Cr T848 ISP I 600/IP/Id j ^ 9 £<"-3 I ^ ~ r m ' 7? "*1 I Preferably a first panel is connected to a second panel to form a corner of the building or the corner of a room.

More preferably in this corner connection a spacing washer is provided on the threaded fastener to space the edge face of the first panel, slightly away from the main face of the 5 second panel By this means it is possible to form a joint space allowance which then can be filled with a sealant to weatherproof the joint. Typically such a joint space allowance is of the order of 15-20 mm.

In another aspect, the invention provides a kit-of-parts for the provision of a corner connection in tilt-up panels, the kit-of-parts including a void former as described above, a 10 threaded fastener, a threaded socket to be embedded in the edge face of one of the panels, and an apertured space to be fitted in the joint space between the panels.

In another aspect the invention provides a method of forming a reinforced concrete panel which comprises locating in spaced relation near to an edge of a mould for a concrete panel a plurality of void formers and locating around one or more of the void formers a U-shaped 15 portion of a reinforcement rod before pouring concrete into the mould.

In another aspect the invention provides a concrete panel made by the method of the preceding paragraph These and other aspects of this invention, which shall be considered in all its novel aspects, will become apparent from the following description, which is given by way of example 20 only, with reference to the accompanying drawings, in which: DRAWINGS Figure 1 is an exploded view of a preferred corner connection, Figure 2 illustrates an isometric view of a preferred void former, Figure 3 is a plan view of the void former of Figure 2, Figure 4 illustrates an example of a threaded socket for use with this invention, 4 Q i) M r I J W L* StW~ '•"'J' T848JSP1 600/J P/ld 1 C * "T Figure 5 shows an apertured space for use with this invention, Figure 6 illustrates part of a mould for a reinforced concrete panel with one void former in place and reinforcement rods located around it, and Figure 7 is a view of the void former and one of the associated reinforcements on a 5 larger scale Example 1 In Figure 1 a first panel 10 is shown by broken lines, and this panel has an edge face 11 in which a threaded socket 12 is embedded. The threaded socket is shown in more detail in Figure 4 discussed below. A second panel 15 is provided with a stepped aperture 16 passing 10 through the main faces of the panel 15 close to the end of the panel so that the stepped aperture 16 can be aligned with the position of the threaded socket 12 in panel 10.

This stepped aperture corresponds to the shape of the void former 20 shown in Figure 2 and Figure 3 It has a first main cavity 17 which is substantially box shaped, and has a larger cross sectional area than the shape of the second cavity 18 which is substantially oval in cross 15 section This oval portion extends from the first cavity through the remainder of the panel to an oval shaped opening on the main face 19 of the panel which is the face adjacent the edge face 11 of panel 10. A washer 30 is positioned in the first cavity 17, and preferably this is a rectangular or square steel washer, preferably galvanised, having an aperture capable of receiving a threaded bolt 31. The threaded bolt is long enough to pass through the second 20 cavity 18 into engagement with the threaded socket 12. The first cavity 17 is large enough to accommodate the head 32 of the bolt so that it can be tightened in situ, to secure the panel 15 to the edge face 11 of panel 10.

Before the bolt 31 is engaged with the threaded socket 12, it is preferable that a spacer 52A is positioned on the bolt, to make allowance for a joint space. Preferably this spacer 52A is 25 formed from a plastics material, and is relatively thick, typically of the order of 15 mm - 20 mm, and preferably the plastic material is somewhat resilient. As shown, the spacer 52A is m the form of a rectangular block 52A (and is discussed in more detail below with reference to Figure 5). , '' 1 - ^ .i I ; i. ^ i 19 jul i:j T848ISP1 600/JP/ld j I ~ ~ * ■ — —.j It is preferred that the spacer has a diameter somewhat less than the width of panel 10 so that the position of the spacer can be concealed by a suitable sealant inserted into the joint space 35 when the bolt 31 has been fully tightened into socket 12. By this means a suitable sealant can be inserted into the joint space to make the corner connection weatherproof. The internal 5 corner 36 can be plastered, or covered with an edge strip, or any other means to cover the joint space and the sealant.

The threaded socket 12 shown in Figure 4 can be a commercially available threaded socket, or can be especially made for use with this invention. Typically such a threaded socket has a cylindrical body 33, an anchoring flange 44 at one end thereof, and a transverse aperture 45, 10 near the anchoring flange 44, remote from the threaded end 47 of the socket. This aperture 45 can be used for the insertion of an anchoring pin or the like, which can be placed in the aperture 45 at the time that it is being cast into the panel, so that it is fully anchored in place. This anchoring pin has not been shown in Figure 1. Such an anchoring pin is optional.

The stepped aperture in panel 11 is preferably created by a void former 20 as shown in 15 Figures 2 and 3. This void former has a first member 21 which is substantially box shaped, having a base 22 which is at right angles to a second member 23. The void former is preferably hollow and injection moulded from plastics material with a separate end cap which can be clipped into place to fully enclose the void during the pouring of the concrete.

Preferably the void former 20 is tapered from its outside bottom face 25 through to its top 20 most face 26 at the end of the second member 23. Thus, for example the first portion 21 is a substantially rectangular pyramidal shape having a taper of approximately 1-5°, more preferably a taper of approximately 2°.

Protruding from the face 22 of the first member 21 is a substantially oval second member 23. This has a major axis 24 and a minor axis 28. This allows the member 23 to form a slot in 25 the panel 11 to allow the bolt 31 to move up or down within the resulting slot. Preferably the minor axis 28 is slightly greater than the diameter of the bolt 31, and the major axis is at least 1.5 times the diameter of the bolt 31, and more preferably is approximately twice the diameter of the bolt 31 to enable the bolt to move up or down in the resulting slot (shown as a vertical slot in Figure 1) This relationship is shown schematically in Figure 3, which is a f; U ... „ 19 Jul Z;:J T848ISP1 600/IP/Id n S— » t — ! plan view of the void former of figure 2 onto which is superimposed the relative size of the bolt 31 and the relative size of the rectangular washer 30 both shown by broken lines. Figure 3 shows the tapered shape of the first member 21, although the slight tapering of the member 23 has been omitted for the purpose of illustrating the relative size of the bolt and washer 5 relative to the size of the void former 20.

Portion 23 preferably has a pair of flat sides 27 and semi circular ends 29 so that the bolt 31 can move fully from one end of the slot to the other (after removal of the void former).

The apertured spacer 52A is shown in Figure 5. This preferably has parallel end faces 39A, an off-set aperture 50A passing there-through and a thickness 51 of approximately 16 mm to 10 provide for the joint space. The rectangular spacer washer 52A with its off-set hole 50A is designed to be easily inserted by hand when the panels are held upright, so that a worker on a ladder or other support can push the spacer washer into the joint space 35 with a portion of the spacer protruding from the joint space. The worker then inserts the bolt (and washer 30) into the stepped aperture 16 and through hole 50A in the spacer washer, and into engagement 15 with the threaded socket 12. At this point he can let go of the spacer washer so that it swings down under its own weight - to hang substantially vertically within the joint space, suspended from the bolt It no longer protrudes from the joint space so that the sealant can fill the joint and conceal the bolt and spacer.

A suitable material for this spacer would be a resilient plastics material such as nylon, 20 polyurethane, or it could be formed from a resilient material such as rubber or neoprene. Preferably the material of the spacer is water resistant. It would also be possible to use a metal washer in place of the plastic washer, although this is less preferred because of the possibility of corrosion.

Example 2 Formwork 110 provides a mould into which concrete will be poured to make a panel, e.g. for a wall At spaced intervals along and near to one edge of the formwork void formers are located, one of which is illustrated at 111. As shown in Example 1 each void former is a hollow structure, preferably moulded from a cheap plastics material, having a first, box-like portion 112 opening to the floor of the mould 110 and a narrower, second portion 113 T848JSP1 600/IP/Id 19 „ul z;:o upstanding therefrom. The distal end of the narrower portion 113 is closed and in the example illustrated has a tell-tale 114 which, after the concrete is poured, will project from the concrete to assist in locating the void former in the finished panel.

In accordance with a feature of this invention the box-like portion 112 of each void former 5 has a height above the floor of the mould 110 similar to that of a succession of "bar stools" distributed elsewhere over the floor of the mould. In known manner these bar stools, one of which is shown at 118, support reinforcing rods 115, 116 and 117 above the floor of the mould 110 so that after the concrete is poured they will be located within the concrete more-or-less centrally of the finished panel The box like portions 112 of the void formers serve 10 the same purpose as the bar stools in supporting the reinforcing rods at the associated edge of the mould.

A longitudinal reinforcement 116 is supported at intervals along its length by bar stools such as 118. Across the reinforcement 116, and others (not shown) parallel to it, are laid U-shaped transverse reinforcements 115 and 117, the web portion 115A and 117A of each U-15 shaped reinforcement resting on the box-like portion 112 of an associated void former.

Particularly the reinforcement 117, which is only slightly wider than the portion 113 of the void former, will tend to prevent displacement of the void former when concrete is poured into the mould 1110 The web portions 115 A and 117A of the transverse reinforcements will both prevent the void former migrating to a position too close to the edge of the panel. This 20 would be undesirable because the resulting void, if close enough to the edge, would encourage concrete between the void and edge to crumble.

As described in Example 1, the hollow plastics void former 111 may be knocked out of the void which it has formed in the set concrete, or it may be destroyed or simply deformed when a bolt (not shown) is subsequently passed through the void to engage a threaded collar 25 embedded in an edge of another panel (not shown) to which the panel with the voids is to be connected. In either event, the resulting stepped aperture in the concrete panel is reinforced by its associated U-shaped bar embedded in the concrete which helps to prevent pull-out of the bolt if an excessive load is placed on the corner connection. i li 1 1 LwLLv IWI. • • ' L. t i Ui t "C.- Of I- i 1 9 J VjL i.wv/j ; T848JSP1 600/JP/ld p( r f. t \ >z ~s IN USE In use, panel 10 can be cast with a number of the threaded sockets 12 situated in the end face 11 During casting, the threaded socket will be provided with an end cap such as a plastic end cap to prevent the introduction of concrete into the threaded portion of the socket (the 5 threaded portion typically being a blind threaded portion, so that there is no connection between aperture 45 and the threaded portion 47). The threaded socket can be supported on appropriate supports as the panel is being cast, or can be connected to the form work on the edge of the panel In order to cast panel 11, the void formers 20 are placed in a line adjacent one edge of the 10 required panel 11 at the required spacings in order to coincide as closely as possible with the position of the threaded sockets 12. The panel 11 will be cast flat, within appropriate form work. The void formers can be adhered to the casting base by an appropriate light adhesive, light enough that the void former will remain withm the panel once it is lifted off the casting surface and stacked or left to cure. They can be adhered either way up, though they have been 15 designed to be adhered with the end cap attached to the floor of the mould space. They can also be held in place by the U-bars of Example 2.

The panels 10 and 11 can then be lifted into position on the building, by appropriate lifting means (in tilt-up panel construction these panels are large, and are typically lifted into position by having high bolts or the like cast into the panels during manufacture, to enable a 20 crane to lift the panels by tilting them from the horizontal to the vertical position).

Before the panels are connected together, the void formers preferably need to be removed from panel 11. Because of their construction, the void formers can be physically ejected by driving them out with a pin, and a hammer or the like. The removal of the void formers will typically take place after the panel has been lifted into the vertical position, but before the 25 panel has been moved close to panel 10.

When panel 15 is in place, close to but not abutting against panel 10, the bolts 31, washers 30 and spacers 52A can be positioned so that bolt 31 would pass through panel 15 with the threaded portion of the bolt protruding from the face of panel 15 which faces towards the edge face 11 of panel 10. Because the void former leaves an elongate vertical slot as shown 1Q MM J JwL L^J J t S — — i < • ~ r in Figure 1 when the panel is in the vertical position, the bolt 31 could be moved up or down within that slot to align it with the now exposed threaded socket 12. Any end caps or coverings on the end of the sockets will have been removed by this time. The bolt 31 can then be secured to the threaded socket 12 to form a tight corner connection.

Although Figure 1 only shows one such aperture 16, and one such threaded socket 12 it will be appreciated that a number of these sockets and corresponding apertures will be provided in the two panels to provide a secure connection between the two vertical panels forming a corner of a room, or a corner of the building Figure 1 shows only an external corner of the building, so that the joint space 35 can then be filled with a suitable sealer, in order to 10 weatherproof the corner. The internal corner of the building can then be plastered or the like to conceal the sealant Similarly the external corner of the building can be plastered or covered over, and the outer cavity 17 of the stepped aperture can be covered by a suitable sealant or by a moulded end cap It will be appreciated that the invention can be used in any edge connection between panels 15 ma building construction It is most preferred for a corner connection between two vertical panels, but it could be used where an internal panel butts up against another internal panel not necessarily at the edge of one of the panels (i.e. where one panel provides a divider between two room spaces). Although shown as a connection between two vertical panels, it will be appreciated that the invention can also be used in other orientations, for example a 20 wall could be connected to a pre-cast floor or the like.

VARIATIONS The void former 20 is preferably formed from a plastics material, which is strong enough to enable the void former to be used on a building site, without undue damage during casting of the panels, but at the same time is formed a material which is relatively low cost, and is 25 preferably water resistant. The most preferred material for the void former is a plastics material, such that the void former could be injection moulded, blow moulded, or mass produced in some other convenient way. If the void formers are injection moulded or blow t '' ' " *" v 1 1 L r~ i M 4- ' "1 I 19 ,ol :::J T848ISP1 600/JP/ld moulded it is preferred that they are provided with a tell-tale 55 or other flexible protrusion from end face 26, enabling their position to be readily located after the panel has been cured. Such a tell-tale facilitates the visual location of the void formers enabling them to be quickly located and removed Preferred materials for the void former would be nylon, or 5 polyurethane, although it is believed that a wide variety of plastics materials could be used, including recycled plastics material. It may also be possible to create the void formers out a meltable material, such that they could be melted or burnt out of the concrete after the panel has cured. This however is less preferred than a material which is tough enough to be physically ejected from the panel after the panel has been cured. For economy of material it 10 is preferable that the void formers are hollow but in some cases it may be practical to make them from a solid material (as our initial prototypes were machined from solid blocks). If the void formers are solid or hollow then they can be physically removed once the concrete has set If they are hollow, it may be convenient in some cases to leave the void former in place and pierce its ends to allow the bolt to pass through the void former.

The spacer washer could be formed of shapes other than rectangular (e.g. a circular washer) but we have found that a generally rectangular shape with an off-set hole is advantageous when it comes to inserting the spacer into the joint space.

Other means for reinforcing the stepped aperture other than the U-bars could be used Finally, various alterations or modifications may be made to the foregoing without departing 20 from the scope of this invention. i 19 2:; I T848JSP1 600/JP/ld .

Claims (10)

WHAT WE CLAIM IS: 33

1. A method of connecting cast concrete building panels to one another wherein an edge face of a first panel is abutted against a main face of a second panel, and wherein the first panel has one or more threaded sockets embedded in or along said edge face thereof, with the exposed ends of the threaded sockets facing towards the main face of the second panel, and the second panel is provided with at least one aperture passing through and aligned with one of said sockets in the first panel,, said aperture being stepped within the panel with said aperture having a narrow portion opening onto the main face of the second panel and a wider portion accessible from the opposite face of the second panel and a threaded fastener provided through the aperture into engagement with the threaded socket to secure the second panel to the edge face of the first panel.

2. A method of connecting concrete building panels to one another as claimed in claim 1, wherein the aperture in the second panel is produced by casting the concrete panel with one or more stepped void formers positioned in the panel during the casting of the concrete, so that the one or more void formers either (a) can be removed once the concrete has set or (b) can be left in place if the stepped void formers are hollow.

3 A method of connecting concrete building panels to one another as claimed in claim 2, wherein the stepped void formers are removed once the concrete has hardened.

4. A method of connecting concrete building panels to one another as claimed in any preceding claim wherein the narrow portion of the aperture is in the form of an elongate slot capable of allowing a fastener such as a bolt to be moved up or down within the slot in order to assist in alignment of the bolt with a threaded socket in the first panel. INTELLECTUAL PROPERTY OFFICE OF NZ. 2 3 FEB 2001 T848J SPl /JP/ds received - 13 - 33 6 490

5. A void former capable of being cast in concrete for use in the method of this invention, said void former having a first member and a second member protruding therefrom, wherein said first member is a substantially box like shape, having a first face at substantially right angles to the central axis of the second member, and wherein the second member is a substantially oblong shape having a minor axis approximately equivalent to the diameter of the bolt or the like to be used in the aperture once formed in the panel, and a major axis which is greater than the minor axis to allow movement of the bolt within the aperture so formed, to assist in aligning the bolt with a threaded socket in another panel.

6. A void former as claimed in claim 5 wherein the void former is a hollow member.

7. A void former as claimed in claim 5 or 6 wherein the first member and the second member are tapered slightly to assist in removal of the void former from a concrete panel once cast.

8. A void former as claimed in claim 7 wherein the second member has a cross section which is approximately oval, having a pair of straight sides, and having semi-circular ends so that a cylindrical bolt or the like can be moved fully within the slot defined by the aperture after removal of the void former.

9. A concrete panel having at least one aperture passing there-through and capable of being aligned with a socket in another panel,, said aperture being stepped within the panel with said aperture and having a narrow portion opening onto the main face of the second panel and a wider portion accessible from the opposite face of the second panel to allow a threaded fastener provided through the aperture into engagement socket to secure the second panel to the edge face of the first panel. T848JSPl/JP/ds with the threaded INTELLECTUAL PROPERTY OFFICE OF NZ. 2 3 FEB 2001 received - 14-

10. A building in which at least two concrete panels have been connected together by the method as claimed in any one of claims 1 to 4. INTELLECTUAL PROPERTY OFFICE OF N.Z. 2 3 FEB 2001 received T848JSPl/JP/ds