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Title:
CAST-IN FITTINGS FOR CONCRETE COMPONENTS AND SUPPORT CHAIRS THEREFOR
Document Type and Number:
WIPO Patent Application WO/2014/185911
Kind Code:
A1
Abstract:
An assembly comprising a cast-in fitting for incorporation into a concrete component, and a chair for supporting the fitting at a required height from a casting bed, the fitting having a foot (6) supported by and engaged with the chair in such a manner that substantially the entire upper surface of the foot (6) is exposed for direct contact with the surrounding concrete.

Inventors:
BARRACLOUGH ANDREW SAUL (AU)
Application Number:
PCT/US2013/041315
Publication Date:
November 20, 2014
Filing Date:
May 16, 2013
Export Citation:
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Assignee:
ILLINOIS TOOL WORKS (US)
International Classes:
E04G21/14
Domestic Patent References:
WO1982001541A11982-05-13
Foreign References:
FR2695952A11994-03-25
US3878659A1975-04-22
US4580378A1986-04-08
DE19950675C12001-03-08
FR2587269A11987-03-20
Other References:
None
Attorney, Agent or Firm:
HAUPTMAN, Benjamin J. (Suite 1400Alexandria, Virginia, US)
Download PDF:
Claims:
THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An assembly comprising a cast-in fitting for incorporation into a concrete component, and a chair for supporting the fitting at a required height from a casting bed, the fitting having a foot supported by and engaged with the chair in such a manner that substantially the entire upper surface of the foot is exposed for direct contact with the surrounding concrete.

2. An assembly according to claim 1 , wherein the fitting is locked to the chair by resilient clipping means forming part of the chair and engageable with a part of the foot displaced from its upper surface.

3. An assembly according to claim 2, wherein the foot has at least one tab projecting radially outwardly from a peripheral edge of the foot for locking engagement with the chair.

4. An assembly according to claim 2, wherein a peripheral edge of the foot includes a circumferential lip or groove for locking engagement with the chair.

5. An assembly comprising a cast-in fitting for incorporation into a concrete component, and a chair for supporting the fitting at a required height from a casting bed, the fitting having a foot supported by and engaged with the chair in such a manner that substantially the entire upper surface of the foot is exposed for direct contact with the surrounding concrete, the foot being locked to the chair by a resilient clipping action.

6. An assembly according to claim 5, wherein the chair includes resilient clipping means, and the foot has at least one tab projecting radially outwardly from a peripheral edge of the foot, the tab being locked by the clipping means by placement of the foot on the chair and rotation of the foot about a longitudinal axis of the fitting to engage the tab with the clipping means.

7. An assembly according to claim 6, wherein the foot has two such tabs diametrically opposed.

8. A chair for use in an assembly according to claim 5, the chair having a base structure from which the foot of the fitting is supported, and downwardly-projecting legs by which the chair is supported from a casting bed, the base structure having an upwardly- open recess in which the foot is received, and resilient clipping means for locking the foot within the recess to retain the fitting to the chair, the recess being so configured that substantially no part of the base structure overlies the upper surface of the foot when in the locked condition.

9. A chair according to claim 8, wherein the resilient clipping means for locking the foot in the recess is adjacent an outer peripheral edge of the recess.

10. A cast-in fitting for use in an assembly according to claim 5, the fitting having a foot at its base and a stem extending upwardly from the foot for coupling to another component, the foot having at least one tab projecting radially outwardly from a peripheral edge thereof for locking engagement with resilient clipping means of the chair whereby substantially the entirety of the upper surface of the foot remains exposed when the fitting is locked to the chair.

1 1. A cast-in fitting according to claim 10, wherein the fitting is a lifting anchor.

12. A cast-in fitting according to claim 10, wherein the fitting is an internally-threaded ferrule.

13. A cast-in fitting for use in an assembly according to claim 5, the fitting having a foot at its base and a stem extending upwardly from the foot for coupling to another component, the foot having around its peripheral edge a lip or groove for engagement with resilient clipping means of the chair, the lip or groove being displaced from the upper surface of the foot so that substantially the entirety of the upper surface remains exposed when the fitting is locked to the chair.

14. A cast-in fitting according to claim 13, wherein the fitting is a lifting anchor.

15. A cast-in fitting according to claim 13, wherein the fitting is an internally threaded ferrule.

Description:
CAST-IN FITTINGS FOR CONCRETE COMPONENTS AND SUPPORT CHAIRS

THEREFOR

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present invention relates to cast-in fittings for concrete components and more particularly, but not exclusively, to lifting anchors for cast concrete panels, and also to support chairs for such fittings.

2. Description of the Prior Art

[0002] Face lift anchors for incorporation into a concrete panel during casting thereof are typically provided to the user as an assembly consisting of the anchor coupled to a support chair by which the head of the anchor is supported at the required distance from the bed on which the panel is cast. One current form of facelift anchor comprises an enlarged foot at the base of the body of the anchor and which provides the substantive anchorage within the surrounding concrete. In some versions the foot is clipped onto a moulded plastic support chair which sits on the casting bed. Although a variety of clipping techniques can be used to attach the foot to the chair, the resulting configuration is such that in the assembled state when the anchor is clipped to the chair, there is a substantial coverage of the upper surface of the foot by the plastic clipping structure such as by an annular flange which overlies the upper surface of the foot. Investigations by the present inventor have determined that when the anchor is under lifting load, the high compressive loading applied between the upper surface of the foot and the overlying plastic layer formed by the annular flange or similar tends to fluidise or plasticise that layer thereby creating a void between the upper surface of the foot and the adjacent concrete and which tends to reduce the lifting capacity of the anchor.

[0003] Lifting capacities of anchors are conventionally determined by empirical testing methods and although the mode of interaction between the overlying plastic layer and the foot of the anchor as discussed above was not previously understood, steps were taken to ensure that anchors fulfilled the required load ratings. [0004] It is to be understood that although the above discussion is principally in relation to footed lifting anchors, the effects described are also applicable to other footed cast-in fittings such as footed ferrules.

SUMMARY OF THE INVENTION

[0005] Based on the understanding now acquired by the inventor, the present invention relates to modifications in foot design and clipping mechanisms for cooperation with the foot.

[0006] According to the present invention there is provided an assembly comprising a cast-in fitting for incorporation into a concrete component, and a chair for supporting the fitting at a required height from a casting bed, the fitting having a foot supported by and engaged with the chair in such a manner that substantially the entire upper surface of the foot is exposed for direct contact with the surrounding concrete.

[0007] In a preferred embodiment the fitting is locked to the chair by resilient clipping means forming part of the chair and engageable with a part of the foot displaced from its upper surface. In one form the foot has at least one tab projecting radially outwardly from a peripheral edge of the foot for locking engagement with the chair. In another form the foot includes a peripheral lip or groove for locking engagement with the chair.

[0008] The present invention also provides a chair for use in the assembly defined above.

[0009] The invention also provides a cast-in fitting for use in the assembly defined above.

[00010] In a preferred embodiment the fitting is a footed face lift anchor preferably produced by a hot drop forging operation. In another embodiment the fitting is an internally-threaded footed ferrule.

BRIEF DESCRIPTION OF THE DRAWINGS

[00011] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which.

[00012] Figures 1 to 5 are views of a preferred embodiment of a face lift anchor;

[00013] Figures 6 and 7 are views of a preferred embodiment of a plastic support chair for the anchor;

[00014] Figure 8 is a section on line A-A of Figure 6;

[00015] Figure 9 is an enlarged view of a detail B in Figure 8;

[00016] Figure 10 is a perspective view showing the anchor and chair prior to assembly;

[00017] Figure 1 1 is a perspective view showing the assembly of anchor and chair with the anchor locked thereto;

[00018] Figures 12 and 13 show alternative forms of locking structure for the foot of the anchor; and

[00019] Figure 14 shows the application of the invention to an internally-threaded ferrule.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[00020] Figures 1 to 5 of the accompanying drawings show a lifting anchor of generally plate-like form having a head 2 with an eye 4 for releasable engagement with a ring clutch of lifting equipment, and an enlarged foot 6 at the opposite end to the head. The foot 6 is of generally circular form with an upper surface 8 of generally conical form and it is that surface which carries the substantive loading at the commencement of lifting when the panel is being raised from the casting bed. Locking tabs 10 for cooperation with the chair subsequently to be described extend radially outwardly from the peripheral edge of the foot 6. In the embodiment shown there are two such tabs 10 diametrically opposed and having an arcuate outer edge but it is to be understood that there could be other than two such tabs, for example three or more tabs and their shape may be different to that shown. There could even be just a single tab of sufficient angular extent for locking interaction with a chair of appropriate design.

[00021] A chair designed for use with the anchor is shown in Figures 6 to 1 1. The chair comprises a base structure 20 having downwardly-projecting legs 22 by which the chair is supported from the casting bed. In the embodiment shown the legs 22 are of generally tubular form open at their upper ends, with foot portions 24 of reduced diameter at their lower ends and of a size to engage into the open upper ends of the legs of a like chair whereby two such chairs can be stacked in order to increase the height of the anchor above the casting bed. Although this is a preferred characteristic, it is not essential. The base structure includes a cylindrical recess 26 in which the foot 6 of the anchor is received and supported. The recess has radial extensions 28 shaped to receive the tabs 10 when the anchor is initially assembled to the chair. Those extensions lead into undercut recesses 30 in the periphery of the recess 26 whereby following initial location of the foot 6 in the recess 26, rotation of the anchor will then to engage each tab 10 in its corresponding recess and as a consequence the anchor is retained to the chair against axial movement. Rotation of the tabs 10 into their engaged positions within the undercut recesses 30 also results in locking of the foot in that configuration by means of a clipping mechanism which prevents rotation in the release direction. In the embodiment shown the clipping mechanism comprises a single spring clip 32 which interacts just one of the tabs 10 and which is sufficient to prevent reverse rotation of the entire foot. In the specific embodiment shown the spring clip 32 is formed by a resilient base of the extension 28 into which the tab 10 is received when the anchor is initially assembled to the chair and in that condition the tab 10 depresses the clip 32. Subsequent rotation of the tab 10 out of the extension 28 and into the adjacent undercut recess 30 results in release of the clip 32 which then moves into a position in which it blocks the tab against release rotation out of the recess.

[00022] It is to be understood that the particular form of clipping mechanism is not critical and a variety of other mechanisms could be incorporated as part of the structure of the chair to lock the foot against release. It is however important to note that the locking interaction between the anchor and chair does not result in coverage of the conical upper surface 8 of the foot 6 by part of the chair whereby the entirety of that surface will be in direct engagement with the surrounding concrete and this is enabled by the fact that engagement of the anchor with the chair takes place away from that surface by the tabs projecting from the edge of the foot and their interaction with the undercut recesses. The locked condition of the anchor to the chair is shown in Figure 1 1 which clearly illustrates the exposure of the upper conical surface 8 of the foot 6.

[00023] As a consequence of the direct engagement between the concrete and upper conical surface of the foot, a higher effective lifting capacity is able to be achieved in comparison with the same anchor in which a plastic interface exists between that surface and the concrete. A consequence of this is that to meet a required lifting capacity, the size of the anchor can be reduced in relation to comparable current anchors thereby reducing material costs.

[00024] It is to be understood that it is not essential that locking engagement of the foot with the chair is achieved by a rotational action. For example, a practical alternative would be to incorporate a spring clip in the wall of each extension for receiving the tabs whereby when the anchor is mounted to the chair the tabs are immediately retained within the extensions after passage past the spring clips which thereby prevent removal of the anchor.

[00025] In a further alternative which achieves a locking action whilst ensuring that the upper conical surface of the foot remains fully exposed, the peripheral edge of the foot is formed with a continuous lip or a continuous groove engaged by a suitable clipping mechanism when the anchor is engaged with the chair. Figure 12 shows the foot 6 with a continuous lip 40, and Figure 13 shows the foot 6 with a continuous groove 42.

[00026] The anchor can be fabricated in one piece in a hot drop forging operation or by other suitable techniques such as casting or sintering. The head of the anchor could be configured differently to that shown for use with alternative lifting systems.

[00027] The chair including the clipping mechanism which is formed integrally with the remainder of the chair is preferably formed as a one-piece plastic moulding.

[00028] The invention is not limited in its applicability just to concrete lifting anchors but can extend also to other cast-in fittings such as internally-threaded footed ferrules (see Figure 14) which are subject to comparable loading situations within the concrete component.