New Zealand No 334725 International No PCT/AU97/00612
TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION
Priority dates 20 09 1996,05 06 1997,09 07 19097,
Complete Specification Filed 18 09 1997 Classification (6) E04G15/04, E04C5/20 Publication date 29 September 1999 Journal No 1444
NEW ZEALAND PATENTS ACT 1953
COMPLETE SPECIFICATION
Title of Invention Void former
Name, address and nationality of applicant(s) as in international application form
RAMSET FASTENERS (AUST) PTY LIMITED, Maroondah Highway, Croydon North, Victoria 3136, Australia
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VOID FORMER
The present invention relates to a void former for forming a void or recess around the head of a lifting anchor incorporated into a concrete component such as panel or beam prior 5 to casting of the concrete
In the production of concrete components such as panels or beams it is often necessary to incorporate lifting anchors into the structure of the component prior to casting of the concrete, die lifting anchors having an exposed lifting head or eye for attachment to a lifting 10 clutch for lifting the component into position on the site Conventionally, a removable void former is placed on the head portion of the anchor prior to casting of the concrete and when the concrete has set the void former is removed so as to define within the surface of the concrete component a void around the head portion of the anchor for attachment of the lifting clutch
One current type of void former m widespread use is of two- part construction with the two parts being separate and assembled over the head of the anchor prior to casting, the two parts being connected along a vertical median plane In this type of void former, the two parts consist of relatively complex plastics mouldings and suffer from the disadvantage that 20 if the void former is accidentally stepped on prior to casting the load applied to the void former can cause the void former to open at the plane of connection of the two parts and to skew relative to the anchor Usually this skewing movement is not detected prior to casting, with the result that the void is not properly formed around the anchor head during casting, in this event, following removal of the void former after the concrete has set action is required, 25 for example using a jack hammer, to form an adequate void around the anchor head sufficient to enable attachment of the lifting clutch
Accordmg to the present invention there is provided a void former for application to the head portion of a lifting anchor prior to casting concrete around the anchor, said void 30 former including a body having an interior space for receiving the head portion of the anchor through an aperture in the underside of the body, and a lid closing an upper end of the body,
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said lid being secured to the body and the lid having within the body locking means engageable with the head portion of the anchor to lock the void former to the anchor, said body being formed as a plastics moulding having an open upper end, and the lid being formed as a plastics moulding and being applied to the open upper end of the body whereby to close 5 the open upper end
Still further according to the invention, there is provided a void former for application to the head portion of a lifting anchor prior to casting concrete around the anchor, said void former including a body having an interior space for receiving the head portion of the anchor 10 through an aperture in the underside of the body, and a lid closing an upper end of the body, said lid being secured to the body and the lid having locking means engageable with the head portion of the anchor within the body to lock the void former to the anchor, said body being formed as a plastics moulding having an open upper end, and the lid being formed as a plastics moulding and being applied to the open upper end of the body whereby to close the 15 open upper end prior to application to the anchor, and the locking means being such that application to the void former to the anchor with the lid already applied to the body causes the locking means to move into snap-m engagement with the anchor
Further according to the invention, there is provided a void former for application to 20 the head portion of a lifting anchor prior to casting concrete around the anchor, said void former including a substantially rigid body and a lid applied to the body prior to application of the void former to the anchor, the lid having within the interior of the body at least one locking lug for snap-m engagement with the head of the lifting anchor when the void former is applied thereto, the lid being attached to the body m such a manner that accidental release 25 of the lid therefrom is precluded, and the lid having sufficient flexibility to permit removal of the void former by leverage of the lid from the body by applying a tool to the lid
In the preferred embodiment of the invention, the body is of one-piece construction and the lid includes snap-action engagement means for releasable engagement with the eye of 30 the lifting anchor whereby to lock the anchor to the void former The lid is secured to the body prior to application to the anchor either by mechanical fastening means and/or by
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adhesive or a welded connection The form of connection between the lid and body is such as that although the lid is able to be removed from the body as part of the process of removing the void former from the anchor after the surrounding concrete has set, the lid cannot accidentally or easily be removed from the body, and the force and actions required to 5 remove the hd from the body will result m damage occurring to the lid and/or body
An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which
Figure 1 is a perspective view showing in a schematic manner a void foi mer in
rCT/AU97/00612
accordance with a preferred embodiment of the invention for application to the head portion of a lifting anchor,
Figure 2 is a perspective view showing the void former when applied to the anchor, 5 Figure 3 is a perspective view showing the body of the void former,
Figure 4 is a perspective view showing a lid of the void former prior to application to the body,
Figure 5 is a side view ot the assembled void former,
Figure 6 is a transverse seuion of the void former, the section being taken on lint A-A of Figure 5, and
Figure 7 is a longitudinal seLtion through the void former
In accordance with a preferred embodiment of the invention, the void former 2 is designed for use with a lifting anchor 4 having a head portion with a lifting eye 6 for cooperauon with a lifting clutch The void former 2 which fits over the head portion of the
anchor 4 comprises a hollow body 8 with a recess 10 in its underside and through which the head portion of the anchor 4 can extend Within the body 8, the recess 10 is bounded by transverse walls 12 which extend upwardly over the entire height of the body 8 and are adapted to engage the opposite bide faces 14 of the head portion of the anchor 4 to thereby locate the void former 2 relative to the head portion of the anchor 4 The open end of the
body 8 is closed by a separate lid 16 having on its underside downwardly projecting lugs 18 which he within recessed portions 12a of the two transverse walls 12 When the void former 2 is pushed over the top of the head portion of the anchor 4, the lugs 18 move along the opposed side fates 14 of the anchor head poruon and then snap into the eye 6 of the anchor head portion in order to lock the void former 2 to the head portion
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FCT/AU97/00612
The lower edge portion of the lid 16 when assembled to the body 8 abuts against a peripheral shoulder 20 at the upper end ol the body 8, the shoulder 20 being bounded internally by an upstanding peripheral lip 22 which lies against the inner surface of the lower edge portion of the lid 16 in order to provide an effective seal against ingress of concrete 5 slurry into the void former 2 during casting Secure attachment of the lid 16 to the body 8 is eftected by snap-in engagement of lugs 24 on the inner surface of the lower edge portion of the lid 16 into locking apertures 26 formed within locking portions 27 of the peripheral lip 22 in the body 8
The outer edge portion 16a of the ltd 16 has in vertical extent a curvature which follows the vertical curvature of the body 8 in order to facilitate removal of the void former after casting
The lid 16 and body 8 are each formed by injection moulding in a suitable plastics 15 During the moulding of the lid 16, slot-like cavities 28 will be formed through the upper surface of the lid 16 directly above each of the locking lugs 24 for passage of tooling required m the moulding of lugs 24 The locking portions 27 of the peripheral lip 22 include at then upper edges, ribs 27a which fit into the cavities 28 in the lid 16 in order to close those caviLes against entry of slurry into the void former during casting It is to be noted that there 20 is also an edge to edge engagement between the under surface of the lid 16 and the upper surface of the projecung locking portions 27 adjacent the ribs 27a in order to minimize the risk of entry of a slurry which might penetrate between the ribs 27a and the cavities 28 In addition to closing the moulding cavities 28 in the lid 16, the engagement between the ribs 27a and the cavities 28 will act to minimize deformation of the lid 16 when a point loading 25 is applied to the lid 16, such as by a person standing on the void former 2, and which might otherwise result in dcflecuon of the edge of the lid 16 to an extent to cause disengagement of one or more of the locking lugs 24
The moulding of the depending locking lugs 18 also results in the formation of tool 30 cavities 30 within the central part ot the hd 16 directly above the head of the anchor and these
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cavities 30 will also provide opporlunity for visual inspection ol the anchor within the void former Adjacent these cavities 30, the underside of the lid 16 includes a pair of transverse ribs 31 which sit firmly against the upper edges ot the upstanding walls 12 in order to prevent penetration ot slurry into the two outer zones 36 of the body 8 defined at the outer sides of 5 the upstanding walls 12, as a result of passage of slurry via the cavities 30 The underside ot the hd 16 also includes inclined ribs 32 in the area between the transverse ribs 31 and which sit against the upper edge of the anchor 4 to provide firm support for the lid 16 from the head of the anchor 4 Further reinforcement for the lid 16 is provided by pairs of ribs 38 extending outwardly from the transverse ribs 31 to the end edges of the lid 16 It is, to be 10 noted that the ribs 38 are splayed in order to provide a large central area through which a removal tool such as a screw driver or pick can penetrate in order to facilitate removal of the void former 2 after casting as will be described
The void former 2 consisting of lid 16 and body 8 is supplied to the consumer as a 15 pre-assembled component The void former 2 is applied to an anchor simply by pushing the void former 2 over the head of the anchor 4 to which it will engage by a snap-in engagement of the lugs 18 within the eye 6 Either the void former 2 can be supplied to a consumer for mourning to an anchor 4, or alternatively, an assembly consisting of an anchor 3 with the void former 2 mounted thereon can be supplied Removal ot the void former 2 from the anchor 20 4 after casting can be achieved with or without removing the lid 16 which carries the locking lugs 18 In the simplest technique a screw driver or other elongate tool is inserted through one of the cavities 30, along the length of recessed portion 12a and into the region between the lower portion of wall 12 of recess 10 and the anchor 4 With the screw driver or other tool thus positioned the anchor 4 can be used as a fulcrum to apply the removal torce to the 25 void former via the lower portion of wall 12 It will be apparent that the direction of this force is generally tangential to the curve of body 8 This technique is thus particularly effective in removing the void former from the casting During the removal process the void former will generally yield sufficiently to be dislodged from the anchor merely by the application of the above force Alternatively, the application of the force may only loosen 30 the former from the casting and the anchor on one side only, in which case the force is
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-reapplied in the same manner to the other side of the void former to complete the removal In another approach the lid 16 can first be removed and the tool inserted into rccessed portion 12a and a force applied as described above
It is to be noted that due to the locking system provided between the lid 16 and body 8, when the lid 16 has been applied to the body 8 the lid 16 is not easily removable from the body 8 Removal of the lid 16 can only be achieved by "levering" the lid 16 from the body 8 and this may, in some circumstance';, involve destruction of the lid 16 as it is necessary to penetrate the hd 16 with a tool, such as screw driver or pick to facilitate removal, and the removal 10 process may also destroy the integrity ot the locking system between the lid 16 and body 8 However this is not disadvantageous as void formers are traditionally designed tor single usage only and the important consideration is that the lid 16 is very firmly secured to the body 8 and cannot accidentally be dislodged during usage, for example by application ot point loading as may arise if someone steps on the void former and which could result in entry ot 15 slurry into the void former which might then cause substantial difficulties in its subsequent removal It is, however, to be understood that depending on factors such as the relative flexibility of certain of the components removal of the lid 16 may not necessarily result in its destruction, although in all cases the lid is securely attached to the body and cannot accidentally be removed
The embodiment has been described by way of example only and modifications are possible within the scope of the invention
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