AU751863B2

AU751863B2 - Lifting anchors

Info

Publication number: AU751863B2
Application number: AU94225/98A
Authority: AU
Inventors: Ian Moffitt
Original assignee: Cetram Pty Ltd
Current assignee: Illinois Tool Works Inc
Priority date: 1997-12-04
Filing date: 1998-11-30
Publication date: 2002-08-29
Anticipated expiration: 2018-11-30
Also published as: AU9422598A

Description

-1- Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

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Name of Applicant: RAMT FS A IME Actual Inventors: Address for Service: MOFFITT, Ian DAVIES COLLISON CAVE, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

"Lifting anchors" Invention Title: Details of Associated Provisional Application(s) No(s): PP0712/97 filed 4 December, 1997 The following statement is a full description of this invention, including the best method of performing it known to us: IP AUSTRALIA

RECEIVED

3 0 NOV 1998 Q:\OPER\RSH\LIFTING.329 30/11/98;;

MELBOURNE

P:\OPER\RSH\PPOI72-9.CAP -21/5/02 -2- LIFTING ANCHORS The present invention relates to lifting anchors of the type intended to be incorporated into a concrete component prior to casting to provide a lifting point by which the component can be lifted during subsequent erection.

Concrete lifting systems for so-called edge-lift or tilt-lift of concrete panels, beams, columns, and the like involve the use of lifting anchors incorporated into the component during casting, with the head of the anchor being encased within a removable or disposable hollow void former to form within the surface of the component a recess within which the head of the anchor lies for coupling to a releasable lifting clutch. One commonly used form of lifting clutch is a ring clutch having an arcuate locking bolt received within an eye in the exposed head of the lifting anchor within the recess.

:Concrete lifting systems require the use of different types of anchor suited for different °.i components, loads, and type of lift. One previously proposed lifting anchor comprises opposed •.parallel legs of generally sinuous form extending from the head portion. The anchor is cut from a metal plate using non-contact high energy cutting means such as a laser beam or plasma arc.

The head portion of the lifting anchor is then subjected to a pressing or stamping operation to form the lifting eye for receiving the bolt of the ring clutch. The need to subsequently process the cut anchor in a pressing or stamping step to form the lifting eye adds to the manufacturing .costs.

According to the present invention, there is provided a lifting anchor for embedment into a concrete component, said lifting anchor having a head portion with an eye for receiving a locking bolt of a lifting clutch and generally parallel legs extending from the head portion, wherein the anchor is cut from metal plate material using a high energy non-contact cutter, said eye also being cut within the head portion by the cutter, wherein the entire anchor including the eye is cut in a continuous cutting process using the cutter whereby a slot is formed between the eye and an edge of the head portion, the slot extending from a lower part of the eye to a lower snd edge of the head portion in a direction approximately parallel to the axes of the two legs.

P:\OPER\RSH\PP0712-9.CAP 21/5/02 -3- Further according to the present invention, there is provided a lifting anchor for embedment into a concrete component, said lifting anchor having a head portion with an eye for receiving part of a lifting system releasably attached to the anchor, generally parallel legs extending from the head portion, and a slot extending between the eye and a lower end edge of the head portion approximately parallel to the axes of the two legs, wherein the anchor is cut from metal plate material using a high energy non-contact cutter, said eye and said slot also being cut within the head portion by the cutter.

An embodiment of the invention will now been described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a lifting anchor in accordance with the preferred embodiment of the invention; and Figures 2 and 3 are views similar to Figure 1 but showing anchors with alternative profiles of lifting eye and associated slot leading to an end edge of the head portion of the anchor.

As shown in Figure 1 of the accompanying drawings, a lifting anchor for use in a concrete lifting system of the general type discussed earlier comprises a head portion 2 designed for co-operation with a lifting clutch, the head portion having a lifting eye 4 for receiving the locking bolt of the clutch. Opposed parallel legs 6 of generally sinuous profile project from the head portion, the legs 6 being embedded within the concrete component in order to form a firm anchorage with the component. The anchor is cut from metal plate using a plasma arc cutter, a laser cutter or other high energy non-contact cutting method. In this anchor the cutter not only cuts the basic profile of the anchor out of the plate in a continuous cutting operation, but also cuts out the lifting eye 4 in the head portion 2 of the anchor during oooo• go P:\OPER\RSH\PP0712-9.CAP 25/11/98 -4part of the continuous cutting operation. As a result of this, during the cutting process the cutter cuts into the lower part of the head portion 2 during its passage into and from the central part in which the eye 4 is cut thereby forming a slot 8 extending between the base of the eye 4 and the base of the head portion 2, the slot 8 extending in a direction approximately parallel to the axes of the legs 6. The presence of this slot does not result in inacceptable weakening of the head portion but, rather, it has been found to provide improved performance of the anchor. The relevant Australian Standards require lifting anchors to have a degree of ductility at failure loads so that an operator will see an extension of the anchor at such loads giving the impression of the anchor pulling out of the concrete so that immediate steps can 10 be taken before a potentially dangerous lifting situation is reached. The incorporation of the

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Sslot 8 results in the formation of two discrete head sections at either side of the slot which 00.. oi00 provides for improved ductility of the head portion at failure loads. As a result of the see improved ductility the head portion will be subject to greater elongation at failure loads and which will be more easily discernible by the operator thereby allowing corrective action to 0 15 be taken sooner.

The forming of the lifting eye by a cutting step as part of the continuous cutting of the anchor from the metal plate simplifies manufacture and reduces manufacturing costs as the anchor can then be produced essentially as a one-step process.

Figures 2 and 3 illustrate alternative forms of profile for the lifting eye and associated slot leading to the base of the head portion.

Throughout this specification and claims which follow, unless the context requires 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.

The embodiments have been described by way of example only and modifications are possible within the scope of the invention.

Claims

1. A lifting anchor for embedment into a concrete component, said lifting anchor having a head portion with an eye for receiving a locking bolt of a lifting clutch and generally parallel legs extending from the head portion, wherein the anchor is cut from metal plate material using a high energy non-contact cutter, said eye also being cut within the head portion by the cutter, wherein the entire anchor including the eye is cut in a continuous cutting process using the cutter whereby a slot is formed between the eye and an edge of the head portion, the slot extending from a lower part of the eye to a lower end edge of the head portion in a direction approximately parallel to the axes of the two legs.

2. A lifting anchor for embedment into a concrete component, said lifting anchor having a head portion with an eye for receiving part of a lifting system releasably attached to the anchor, generally parallel legs extending from the head portion, and a slot extending between the eye and a lower end edge of the head portion approximately parallel to the axes of the two o legs, wherein the anchor is cut from metal plate material using a high energy non-contact cutter, •.said eye and said slot also being cut within the head portion by the cutter.

3. A lifting anchor according to claim 1 or claim 2, wherein the legs each have a generally sinuous profile. S°

4. A lifting anchor substantially as hereinbefore described with reference to the accompanying drawings. DATED this 21st day of May 2002 CETRAM PTY LIMITED By its Patent Attorneys: DAVIES COLLISON CAVE