NZ583518A

NZ583518A - Void former

Info

Publication number: NZ583518A
Application number: NZ58351808A
Authority: NZ
Inventors: Robert Urquhart Connell
Original assignee: Itw Construction Systems Australia Pty Ltd
Priority date: 2007-11-28
Filing date: 2008-11-17
Publication date: 2011-06-30
Also published as: WO2009068969A3; AU2008243282B2; CN101910529B; TW200940792A; WO2009068969A8; NZ572850A; CN101910529A; AU2008243282A1; WO2009068969A2

Abstract

A void former for application to the head of a cast-in lifting anchor for a cast concrete component, the void former having an upstanding lip (6) around its upper face to define a shallow cavity which will fill with concrete during casting and which can easily be removed when the concrete has set. (62) Divided Out of 572850

Description

<div class="application article clearfix" id="description"> -1 - *10058806278* 583518 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Divided from New Zealand Patent Application No. 572850 filed on 28 November 2008 Davies Collison Cave Reference: 30926476 APPLICANT(S) ITW Construction Systems Australia Pty Ltd Our contact address is: Our address for service is: DAVIES COLLISON CAVE 1 Nicholson Street G.P.O. Box 4387QQ Melbourne 3000 Victoria, AUSTRALIA Telephone: 61 3 9254 2777 Facsimile 61 3 9254 2770 Email: maiI@davies.com.au DAVIES COLLISON CAVE c/- James & Wells Level 9, James & Wells Tower 56 Cawley Street Private Bag 11907 DX CP 34005 Ellerslie Auckland NEW ZEALAND INVENTION TITLE: Void former We, ITW Construction Systems Australia Pty Ltd hereby declare the invention for which we pray that a patent be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: [/ntcllectualTtope^ OFFICE OF fv.Z. 2 4 FEB 2010 Received C:\NRPortbl\DCC\PLB\2731855_l.DOC - 19/2/10 5 8 3 5 1 8 C:\NRPortbl\DCC\PLB\273l957_I.DOC- 19ATE * 2ERGEFOR2AT - la -VOID FORMER The present invention relates to a void former and more particularly to a void former for use with a cast-in lifting anchor for a concrete component. 5 Cast-in lifting anchors for concrete components such as panels or beams are installed together with the reinforcement prior to casting of the concrete. The anchor has a head designed for co-operation with the lifting equipment. The anchor head carries a removable void former which, when the concrete is cast, forms a recess within an outer surface of the 10 concrete component around the head, so that when the void former is removed the lifting equipment can engage the head within the recess. One current form of lifting anchor marketed under the trade mark SWIFTLIFT by the Reid Construction Systems division of the present applicants has a lifting head of pin head 15 shape. One existing form of void former for use with such an anchor is of moulded plastics in two parts which lock onto the head. This particular form of void former is designed for single usage only as its removal from the head when the concrete has set results in destruction of the void former. In order to remove the void former it is necessary firstly to chip concrete away from the upper face of the void former to expose the void 20 former and that may result in chipping away concrete on the adjacent part of the upper face of the component thereby requiring some remedial filling at a later stage. The void former is then prised away from the anchor head typically by means of a tool, usually a screwdriver, forced through the top of the void former. This usually requires a significant amount of force to be applied particularly when the void former is seated within a support 25 chair by which it was securely held during casting. According to the invention, there is provided a void former for application to the head of a cast-in lifting anchor for a cast concrete component, the void former having an upstanding lip around its upper face t© define a shallow cavity which will fill with concrete during 30 casting and which can easily be removed when the concrete has set. INTELLECTUAL PROPERTY OFFICE OF N.Z. 2 received C:\NRPoitbl\DCC\PLB\2731957_l.DOC- 19ATE * 2ERGEFOR2AT -2- A void former in accordance with a preferred embodiment of the invention is designed for co-operation with a screwdriver or similar tool in predetermined zones which enable the application of force by leverage against the anchor to facilitate removal. 5 Embodiments of the invention will now be described by way of example in which: Figure 1 is a perspective view showing a void former in accordance with a preferred embodiment of the invention assembled to a lifting anchor and mounted to a support chair; Figure 2 is a plan view corresponding to Figure 1; 10 Figure 3 is a end view corresponding to Figure 1; Figure 4 is a side view corresponding to Figure 1; Figure 5 is a schematic cross-section showing the void former engaged with the head of the anchor; Figure 6 is a plan view of one body part of the void former; 15 Figure 7 is an end view of the body part; Figure 8 is a perspective view of the body part; Figure 9 is a section on line B-B of Figure 7; Figure 10 is a view showing the interior structure of the body part; Figure 11 is a view similar to Figure 10 but to an enlarged scale; and 20 Figures 12 to 14 show schematically successive stages in the action of the screwdriver to remove the body part from the anchor head and chair. A void former in accordance with a preferred embodiment of the invention consists of two identical parts 2 of moulded plastics assembled together to fit around the head 4a of a 25 lifting anchor 4. The body of the void former formed by the two parts 2 is generally of hemispherical shape but with opposed sides of the body being flattened. The two parts are assembled together at a vertical plane which bisects those flattened sides. The void former has an upstanding lip 6 around its upper face to define a shallow cavity which will fill with concrete during casting and which can be easily removed when the concrete has set, 30 without chipping the concrete immediately surrounding the top of the void former. C:\NRPortbl\DCC\PLB\2731957_l.DOC- 19ATE * 2ERGEFOR2AT -3- The body part 2 of the void former and its internal structure is shown in detail in Figures 6 to 11. The anchor head 4a fits into a cavity 10 of corresponding cross-section formed between internal walls 12. 5 The anchor with attached void former will normally be used with conjunction with a support chair 14 formed from metal bar onto which the void former clips at the head of the chair so that the anchor 4 is suspended from the void former in the manner shown in Figures 1 to 5. The void former is fastened to the head of the chair 14 by being clipped to the head when the void former is pushed downwardly onto the head. 10 After setting of the concrete following casting, removal of each body part 2 of the void former from the anchor head 4a and from the chair 14 to which it is clipped is effected by the penetration of a tool, preferably a screwdriver, through a predetermined entry zone 16 within the central part of the upper wall of the body part. This entry zone is clearly marked 15 on the upper face of the wall and may be defined by a depression of appropriate shape, the wall thickness being reduced within the depression so that it can easily be broken by the blade of the screwdriver. Figure 12 shows schematically the screwdriver 18 when it has first penetrated the entry zone 16. The screwdriver 18 is then pushed into the interior of the body part 2 with its shaft obliquely inclined as shown in Figure 13 so that the 20 screwdriver blade will engage the inner surface of the end wall of the body part in a predetermined zone. The body part is provided internally with parallel webs 20 (see Figure 11) aligned with the entry zone 16 so that when the screwdriver blade is forced through the entry zone into the interior of the body part it will lie between the webs 20 to ensure that the blade will be guided into the engagement zone 22 which lies between the 25 webs 20 at the inner surface of the body part and defined by wall portions of increased thickness to provide a strong bearing surface for the end of the screwdriver blade. In the embodiment shown the engagement zone 22 is of a ribbed construction which provides the increased wall thickness to carry the engagement force without the need to use significant amounts of plastic material. 30 It will be seen from Figures 12 and 13 that the entry zone 16 is positioned slightly inwardly C:\NRPortbI\DCC\PLB\2731957_1.DOC- 19ATB * 2ERGEFOR2AT -4- from the edge of the anchor head 4a so that when the screwdriver is directed obliquely with its blade contacting the engagement zone 22, the shaft of the screwdriver can engage the edge of the anchor head which will act as a fulcrum so that when the handle of the screwdriver is pushed downwardly, the screwdriver will pivot about that fulcrum so that its 5 blade will push upwardly against the engagement zone and swing the body part 2 upwardly so as to disengage it from the head of the chair and commence its removal from the anchor head. To facilitate this swinging movement, each of the two flattened sides of the body part 2 is formed with an outwardly projecting arcuate segment 26 which rests on an upper bar of the head of the chair as shown in Figure 4 to provide pivot points about which the 10 body part can swing during the initial part of the release movement. While it is necessary that the clipping system retains each body part 2 of the void former firmly to the head of the chair to prevent its dislodgement prior to and during casting, it is necessary that when the deliberate force is applied to the body part 2 to remove it in the 15 manner just described, the clipping system will not unduly impede that process. For this purpose the clipping system is formed by a single moulded clip 30 in the centre of the end wall of the body part 2. The clip, which is moulded integrally with the end wall, is shaped to engage a bar 14a of the head of the chair with a snap action when the void former with engaged anchor 4 is pushed downwardly into the chair 14. It will be seen from Figure 9 20 that the lower face 30a of the clip 30 is curved to permit its easy movement over the bar 14a of the chair so that the bar will seat into a part circular recess of corresponding section defined between upper and lower parts of the clip. It will also be observed that the lower part of the clip is of reduced wall thickness relative to that of the outer wall of the body part. As a result of this reduced wall thickness, when force is applied to remove the body 25 part upwardly in the manner described, that force will act to push the lower reduced wall thickness part of the clip into tight engagement with the bar 14a which will then cause collapse of and thereby destruction of, the lower clip part due to its reduced wall thickness to thereby enable the body part to easily release upwardly from the chair bar 14a. It is to be noted that as the under surface of the lower clip part is only gently curved, the initial 30 engagement of the clip with the bar 14a during assembly will not cause destruction of the clip. C:\NRPortbl\DCC\PLB\2731957_I.DOC- 19ATE * 2ERGEFOR2AT -5- After release of the first body part from the anchor head and chair in the manner described, the second body part is released in the same way. 5 Although the void former of the preferred embodiment illustrated herein is designed for use with an anchor head of pin head design, the invention is not confined to use with that specific type of anchor head and void formers embodying the principles of the invention can be designed for use with anchor heads of other type with appropriate modification to the internal structure of the body parts of the void former to suit the anchor head. 10 The present invention as defined in the claims relates to the passage of the lip around the upper face of the void former to define the shallow cavity which facilitates removal of concrete when set. It is to be understood that this concept is also applicable to other types of void former. 15 The embodiment has been described by way of example only and modifications are possible within the scope of the invention. Throughout this specification and claims which follow, unless the context requires 20 otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers. </div>

Claims

<div class="application article clearfix printTableText" id="claims"> C:\NRPortbI\DCC\PLB\2731957_l.DOC- 19ATE * 2ERGEFOR2AT -6- THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A void former for application to the head of a cast-in lifting anchor for a cast concrete component, the void former having an upstanding lip around its upper face to 5 define a shallow cavity which will fill with concrete during casting and which can easily be removed when the concrete has set.

2. A void former according to claim 1, comprising two substantially identical body parts engageable to the head of the anchor to enclose the head, each body part providing a 10 segment of the upper face and a segment of the upstanding lip.

3. A void former according to claim 2, wherein each body part includes on its outer surface an integrally moulded clip for engagement with a part of a chair by which the void former with lifting anchor depending therefrom can be supported from a casting base. 15

4. A void former according to claim 3, in combination with a said chair for supporting the void former and anchor from a casting base.

5. A void former according to any one of claims 1 to 4 having predetermined zones 20 for co-operation with a screwdriver or similar tool to enable release from the anchor after casting by leverage against the anchor. 'NTEncSSAk PROpERTV OFFICE OF N.Z. 2 4 FEB 2010 received </div>