Flat steel anchor for a pre-cast concrete component

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Patent issued

01/12/1993

Inventor(s):	Fricker, Siegfried
Application	No. 07/839,571 filed on 02/19/1992
Current US Class	52/707, 52/712
Field of search	52/684, 52/689, 52/677, 52/707, 52/712, 52/685, 52/686, 52/687, 52/688, 52/689, 52/714
International Classes:	E04B 138
Examiners
Primary	Scherbel David A.
Secondary	Van Patten Michele A.
Attorney, agent or firm:	Robert W. Becker & Associates
US patent references	1917529, 2291157, 3623289, 3673753, 3788025, 4580378, 4831803, 4835933, 5042219
Foreign patents	4105337 (02/21/1991, DE)

A flat steel anchor for a pre-cast concrete component is comprised of ananchoring portion to be positioned within the concrete component and aconnecting portion protruding from the concrete component. The anchoringportion has lateral bars that enclose therebetween a first opening with afirst opening cross-section in a plane of the flat steel anchor. Thelateral bars are oppositely bent relative to one another and relative tothe plane of the flat steel anchor. The respective outer curved planes ofthe lateral bars form anchoring surfaces of the anchoring portion. Thefirst opening has a second opening cross-section in a plane perpendicularto the plane of the flat steel anchor defined by respective innercurvatures of the lateral bars. The connecting portion has a secondopening for receiving a lifting device.
BACKGROUND OF THE INVENTION
The present invention relates to a flat steel anchor for a pre-castconcrete component having an anchoring portion to be positioned within theconcrete component and a connecting portion protruding from the concretecomponent.
A flat steel anchor of the aforementioned kind is, for example, known fromU.S. Pat. No. 5,042,219. In this embodiment, the flat steel anchor isprovided with at least two sections within the anchoring portion which arehook-shaped and bent in opposite directions relative to one another.Viewed in the longitudinal direction of a reinforcement bar to beinserted, the two hook-shaped sections form essentially a closed shape.The known anchor provides sufficiently large anchoring surfaces for theconcrete and also a good connection with the reinforcement bar, however,the orientation of the flat steel anchor aIways depends on the directionin which the reinforcement bar extends.
It is therefore an object of the present invention to provide a flat steelanchor of the aforementioned kind which may be produced in a lessexpensive and simpler manner. Furthermore, in a preferred embodiment ofthe flat steel anchor the orientation of the anchor should not bedetermined by the position of the reinforcement bars.

What I claim is:
1. A flat steel anchor for a precast concrete component, said flat steelanchor comprising:
an anchoring portion to be positioned within the concrete component, saidanchoring portion having lateral bars that enclose therebetween a firstopening having a first opening cross-section in a plane of said flat steelanchor, said lateral bars being oppositely bent relative to one anotherand relative to said plane of said flat steel anchor, with respectiveouter curved planes of said lateral bars forming anchoring surfaces ofsaid anchoring portion, and with said first opening having a secondopening cross-section in a plane perpendicular to said plane of said flatsteel anchor defined by respective inner curvatures of said lateral bars;and
a connecting portion protruding from the concrete component, when saidanchoring portion is positioned within the concrete component, saidconnecting portion having a second opening for receiving a lifting device.
2. A flat steel anchor according to claim 1, wherein said lateral bars aresymmetrically bent with respect to said plane of said flat steel anchor.
3. A flat steel anchor according to claim 1, wherein said first opening isa stamped elongated hole having a longer dimension extending in adirection of a longitudinal axis of said flat steel anchor.
4. A flat steel anchor according to claim 3, wherein said stamped elongatedhole has a shorter dimension having a length of at least 0.3 times and atmost 0.6 times a length of said longer dimension.
5. A flat steel anchor according to claim 4, wherein said shorter dimensionhas a length of at least 0.35 times and at most 0.5 times a length of saidlonger dimension
6. A flat steel anchor according to claim 1, wherein a first distancebetween a free end of said anchoring portion and said first openingcorresponds at least to a second distance between a free end of saidconnecting portion and said second opening.
7. A flat steel anchor according to claim 6, wherein said first distance isgreater than a width of said lateral bars.
8. A flat steel anchor according to claim 1, wherein said second openingcross-section has a width corresponding at least approximately to a heightof said flat steel anchor.
9. A flat steel anchor according to claim 1, wherein said first openingcross-section is elliptical.
10. A flat steel anchor according to claim 1, wherein said first openingcross-section is oval.
11. A flat steel anchor according to claim 1, wherein said first openingcross-section is in the form of a slotted hole having parallel lateraledges and end sections in the form of semicircles.

BRIEF DESCRIPTION OF THE DRAWINGS
This object, and other objects and advantages of the present invention,will appear more clearly from the following specification in conjunctionwith the accompanying drawings, in which:
FIG. 1 is a perspective view of an inventive flat steel anchor;
FIG. 2 is a side view of the flat steel anchor of FIG. 1;
FIGS. 3a, 3b are respective plan views of an inventive flat steel anchorwith varying openings within the anchoring portion;
FIG. 4 shows a flat steel anchor according to FIG. 1 with a reinforcementbar guided through the opening;
FIG. 5 shows an inventive flat steel anchor with two crossed reinforcementbars;
FIG. 6 shows a flat steel anchor of the present invention with threereinforcement bars arranged in different planes; and
FIG. 7 shows a section of a concrete tube with an inventive flat steelanchor cast therein.
SUMMARY OF THE INVENTION
The flat steel anchor of the present invention is primarily characterizedby an anchoring portion to be positioned within the concrete component,the anchoring portion having lateral bars that enclose therebetween afirst opening having a first opening cross-section in a plane of the flatsteel anchor, the lateral bars being oppositely bent relative to oneanother and relative to the plane of the flat steel anchor with respectiveouter curved planes of the lateral bars forming anchoring surfaces of theanchoring portion, and with the first opening having a second openingcross-section in a plane perpendicular to the plane of the flat steelanchor defined by respective inner curvatures of the lateral bars; and aconnecting portion protruding from the concrete component, when theanchoring portion is positioned within the concrete component, theconnecting portion having a second opening for receiving a lifting device.
The essential advantages of the present invention are that the flat steelanchor, within its anchoring portion, forms a closed triangle of forceswhich may withstand extremely high loads. Furthermore, only very simplestamping steps need to be carried out in order to produce the anchor.Thus, a precise mass production with simple means is possible. It shouldalso be mentioned that the inventive flat steel anchor may be used with orwithout reinforcement bars since the anchoring surfaces, within certainlimits, may also transmit the anchoring forces. Furthermore, thearrangement or orientation of the flat steel anchor within the concretecomponent is entirely independent of the extension of the reinforcementbars if they are provided for the interaction with the flat steel anchor.
In order to uniformly distribute the load over the anchoring surfaces andevenly transmit the forces of the flat steel anchor into the concretecomponent, it is advantageous to bend the bars symmetrically with respectto the plane of the flat steel anchor. Preferably, the first opening is astamped elongated hole having a longer dimension extending in a directionof a longitudinal axis of the flat steel anchor. Due to the elongatedshape of the first opening the lateral bars have a corresponding length sothat bending of the lateral bars is possible without creating too strong atensile stress within the material.
In order to ensure a secure load distribution within the anchoring portionfor a respective load, it is furthermore suggested in another embodimentof the present invention that the first distance between a free end of theanchoring portion and the first opening corresponds at least to a seconddistance between a free end of the connecting portion and the secondopening. Furthermore, it is expedient that the first distance be greaterthan a width of the lateral bars.
Due to the inventive shape of the first opening within the anchoringportion of the flat steel anchor, it is possible to guide one or morereinforcement bars through the opening in any direction desired. To ensurethat during the embedding into the concrete the flat steel anchor issecurely held at a respective reinforcement bar extending in the plane ofthe flat steel anchor perpendicular to the height of the anchor, thesecond opening cross-section of the first opening should be embodied suchthat the flat steel anchor encloses the reinforcement bar in aform-locking manner. For the purpose of obtaining such a cross-section itis expedient that the second cross-section has a width which correspondsat least approximately to the height of the flat steel anchor. For thepurpose of guiding a plurality of reinforcement bars through the commonopening within the anchoring portion in a simple manner, it is suggestedthat the stamped elongated hole has a shorter dimension of a length of atleast 0.3 times and at most 0.6 times the length of the longer dimension.Preferably, the shorter dimension has a length of at least 0.35 times andat most 0.5 times a length of the longer dimension. In this connection, itis suggested that the shorter dimension of the elongated hole is notsubstantially greater than the diameter of the reinforcement bars.
The first opening cross-section, corresponding to the plan view of the flatsteel anchor, may be oval or elliptical. It is especially preferred thatthe opening, respectively, the first opening cross-section, in the planview of the flat steel anchor has the form of a slotted hole havingparallel lateral edges and end sections in the form of semicircles.
DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention will now be described in detail with the aid ofseveral specific embodiments utilizing FIGS. 1 through 7.
The flat steel anchor 1 represented in FIG. 1 is comprised of a connectingportion 2 having a second opening 3 for receiving a lifting device, whichis not represented in the drawing. The flat steel anchor 1 furthercomprises an anchoring portion 4 which is, for example, embedded in apre-cast concrete component The anchoring portion 4 is provided with afirst opening 5 bordered by lateral bars 6 and 7. The lateral bars 6 and 7extend parallel to a longitudinal axis 8 of the flat steel anchor 1.However, the lateral bars 6, 7 are bent relative to the plane of the flatsteel anchor 1 in opposite directions, i.e., relative to the center planeof the flat steel anchor the lateral bar 6 is bent in a downward directionand the lateral bar 7 is bent in an upward direction. Due to this bendingof the lateral bars 6, 7, the opening 5 has, besides a first cross-sectionin the plane of the flat steel anchor (flat extension) a second openingcross-section in a plane perpendicular to the first-mentioned plane of theflat steel anchor. Furthermore, the bending of the lateral bars 6 and 7provides anchoring surfaces 9 and 10 for the concrete. The anchoringsurfaces 9 and 10 are arranged symmetrically with respect to thelongitudinal axis 8 and are therefore suited to evenly distribute forcesunder load.
FIG. 2 shows a side view of the flat steel anchor 1 with the connectingportion 2, the anchoring portion 4 and the first and second openings 3 and5. From this side view, the opposite bending direction of the lateral bars6 and 7 with their anchoring surfaces 9 and 10 is obvious. The opening 5,in the direction of the plane perpendicular to the first plane (flatextension) of the flat steel anchor, has a second opening cross-sectionwith an inner width W which, in the example of FIG. 2, is slightly greaterthan the height D of the flat steel anchor. This second openingcross-section allows a reinforcement bar to be guided through the openingin a plane that is parallel to the plane (flat extension) of the flatsteel anchor.
FIGS. 3a and 3b represent respectively a plan view of a flat steel anchor 1whereby the flat steel anchor of FIG. 3a is provided with a slotted hole51 with two parallel lateral edges 11 and end sections in the form ofsemicircles 12 and whereby the anchor of FIG. 3b is provided with an ovalopening 5". In the connecting portion 2 the opening 3, provided forreceiving a hook or a similar means, is spaced a distance S from the freeend of the flat steel anchor 1. The opening 5', respectively, 5" isprovided with a longer dimension that extends in the longitudinaldirection of the flat steel anchor 1 and a shorter dimension which extendsperpendicular to the first dimension 1. The length of the shorterdimension L in FIG. 3a corresponds to 0.35 times the length of the longerdimension L. The shorter dimension L in FIG. 3b corresponds to 0.5 timesthe length of the longer dimension L. The width of the lateral bars 6 and7 is designated by the letter B. The distance A of the opening 5',respectively, 5" from the free ends of the anchoring portion 4 should atleast correspond to the distance S. In the embodiment shown, the distanceA is slightly greater than the distance S.
FIG. 4 represents a flat steel anchor 1 in a perspective view according toFIG. 1, however, a reinforcement bar 13 is guided through the opening 5.Reference numerals in FIG. 4 which are identical to reference numerals inFIG. 1 correspond to identical parts.
FIG. 5 shows a flat steel anchor 1 with two straight reinforcement bars 14and 15 guided through the opening 5. The reinforcement bar 14 extendsperpendicular to the plane (flat extension) of the flat steel anchor andthe reinforcement bar 15 extends in the plane (flat extension) of the flatsteel anchor whereby the reinforcement bar 15 rests within the bentportions of the lateral bars 6 and 7. Due to the crossed arrangement ofthe reinforcement bars 14 and 15, the flat steel anchor 1 is positionedduring the embedding into the concrete such that an additional securing ofits position is no longer required.
Finally, in a further embodiment according to FIG. 6, a third reinforcementbar 16 is provided. Due to this measure a more favorable forcedistribution within the pre-cast concrete component during lifting by alifting device is achieved.
FIG. 7 shows a cross-sectional view of a section of a concrete tube with anembedded flat steel anchor 1. The connecting portion 2 protrudes from asemi-spherical depression 18 in the surface of the concrete tube 17 sothat the second opening 3 within the connecting portion 2 is easilyaccessible. The anchoring portion 4 is embedded in the concrete tube andtwo reinforcement bars 19 and 20 extend through the opening 5 within theanchoring portion 4. The reinforcement bar 19 is arranged in the plane(flat extension) of the flat steel anchor and the reinforcement bar 20extends in the form of an arc that corresponds to the curvature of theconcrete tube 17 so that it penetrates the opening 5 at a right anglerelative to the plane (flat extension) of the flat steel anchor 1.
The present invention is, of course, in no way restricted to the specificdisclosure of the specification and drawings, but also encompasses anymodifications within the scope of the appended claims.