WO1998012401A1

WO1998012401A1 - Void former

Info

Publication number: WO1998012401A1
Application number: PCT/AU1997/000612
Authority: WO
Inventors: Michael John Finlay; Steven Michael Giddings
Original assignee: Ramset Fasteners (Aust.) Pty. Limited
Priority date: 1996-09-20
Filing date: 1997-09-18
Publication date: 1998-03-26
Also published as: NZ334725A

Abstract

A void former for application to the head portion of a lifting anchor (4) prior to casting concrete around the anchor comprises a substantially rigid body (8) and a lid (16) applied to the body prior to application of the void former to the anchor. The lid has within the interior of the body at least one locking lug (18) for snap-in engagement with the head of the lifting anchor when the void former is applied thereto, the lid being attached to the body in such a manner that accidental release 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.

Description

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 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, the lifting anchors having an exposed lifting head or eye for attachment to a lifting 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 in 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 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, for example using a jack hammer, to form an adequate void around the anchor head sufficient to enable attachment of the lifting clutch.

According 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 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, said lid being secured to the body and the lid having within the body 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 housing 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 open upper end.

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 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-in engagement with the head of the lifting anchor when the void former is applied thereto, the lid being attached to the body in such a manner that accidental release 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 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 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 remove the lid from the body will result in 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 former in 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; 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 of the assembled void former;

Figure 6 is a transverse section of the void former, the section being taken on line A-A of Figure 5; and

Figure 7 is a longitudinal section 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 cooperation 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 side 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 lie 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 faces 14 of the anchor head portion and then snap into the eye 6 of the anchor head portion in order to lock the void former 2 to the head portion. The lower edge portion of the lid 16 when assembled to the body 8 abuts against a peripheral shoulder 20 at the upper end of 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 slurry into the void former 2 during casting. Secure attachment of the lid 16 to the body 8 is effected 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 lid 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. 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 in the moulding of lugs 24. The locking portions 27 of the peripheral lip 22 include at their upper edges, ribs 27a which fit into the cavities 28 in the lid 16 in order to close those cavities against entry of slurry into the void former during casting. It is to be noted that there is also an edge to edge engagement between the under surface of the lid 16 and the upper surface of the projecting 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 is applied to the lid 16, such as by a person standing on the void former 2, and which might otherwise result in deflection 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 cavities 30 within the central part of the lid 16 directly above the head of the anchor and these cavities 30 will also provide opportunity for visual inspection of 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 of the upstanding walls 12 in order to prevent penetration of slurry into the two outer zones 36 of the body 8 defined at the outer sides of the upstanding walls 12, as a result of passage of slurry via the cavities 30. The underside of the lid 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 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 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 mounting to an anchor 4, or alternatively, an assembly consisting of an anchor 3 with the void former 2 mounted thereon can be supplied. Removal of the void former 2 from the anchor 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 force to the 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 the former from the casting and the anchor on one side only, in which case the force is applied 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 recessed 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 circumstances, involve destruction of the lid 16 as it is necessary to penetrate the lid 16 with a tool, such as screw driver or pick to facilitate removal, and the removal process may also destroy the integrity of the locking system between the lid 16 and body 8. However this is not disadvantageous as void formers are traditionally designed for 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 of point loading as may arise if someone steps on the void former and which could result in entry of 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.

Claims

CLAIMS :-

1. 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 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 within the body 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 housing 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 open upper end.

2. A void former according to claim 1 , wherein the configuration is such that the lid is applied to the open upper end of the body whereby to close the open end prior to application of the void former to the head portion of a lifting anchor.

3. A void former according to claim 2, wherein the lid is secured to the upper end of the body by connection means operative to prevent accidental release of the lid from the body during usage.

4. A void former according to claim 2, wherein the lid is secured to the upper end of the body connection means which provides a connection sufficient to prevent release of the lid from the body by accidental application of a load as may arise from a person standing upon the void former during usage.

5. A void former according to claim 3 or claim 4, wherein the connection means between the lid and the body comprises a plurality of two-part fasteners of which one part is carried by the lid and the second part is carried by the body, the respective parts of the fasteners being arranged for snap-in engagement when the lid is applied to the upper end of the body.

6. A void former according to any one of the preceding claims, wherein the void former is locked to the anchor by locking lugs depending from an underside of the lid and engageable with a snap-in action with an eye in the head portion of the lifting anchor, the lugs being at opposite sides of the head portion when the head portion is within the body.

5 7. A void former according to claim 6, wherein the body of the void former includes a central cavity open at its underside for receiving the head portion of the anchor, the central cavity being bounded at each side by walls in the interior of the body and extending into engagement with the lid, the spacing between the walls corresponding substantially to the width of the head portion of the anchor whereby the walls co-operate with the head portion 10 of the anchor to locate the void former relative to the anchor.

8. A void former according to claim 7, wherein the walls include recessed portions for receiving the depending locking lugs.

15 9. A void former according to any one of the preceding claims, wherein a seal is provided between the periphery of the lid and the periphery of the upper end of the body to prevent ingress of concrete slurry into the interior of the body via the junction between the lid and body.

20 10. A void former according to any one of the preceding claims, wherein the lid includes moulding cavities adjacent its periphery, and the body has upstanding projections at its upper end portion which are received in the moulding cavities to close same against ingress of concrete slurry, the engagement of the projections in the moulding cavities also acting to reduce deformation of the lid when a point loading is applied to the lid.

25

11. A void former according to any one of the preceding claims, further comprising a rib structure on the underside of the lid to reinforce the lid against deformation under an applied point loading.

30 12. A void former according to any one of the preceding claims, wherein the connection between the lid and body and between the void former and anchor is such that removal of the void former from the anchor after casting requires application of leverage applied to the lid via a tool applied to the lid.

13. A void former according to claim 12, wherein the lid of the void former is able to be pierced by the leverage-applying tool as part of the removal process.

14. A void former according to claim 12 when dependent on claim 7, wherein the lid has at least one recess extending into the central cavity and the leverage-applying tool is engageable with the lid by penetration through the recess to engage the head portion of the anchor to facilitate removal.

15. 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 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-in engagement with the head of the lifting anchor when the void former is applied thereto, the lid being attached to the body in such a manner that accidental release 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.