DE8521694U1 - Anchors for embedding in heavy loads - Google Patents

Description

Mr A 38 314/bea

Siegfried Fricker

Wurmberger Str. 30-34 26. JüÜ 1985

7135 Wiernsheim

Anchor for encasing heavy loads in concrete.

The invention relates to an anchor for encasing in heavy loads, such as precast concrete components, according to the features of the preamble of claim 1.

For transporting heavy loads, particularly prefabricated concrete components such as prefabricated multi-layer panels, room cells, passage cladding, supports, parapet elements, etc., it is known to cast steel anchors into the prefabricated concrete component in such a way that the head of the anchor protrudes from the surface of the concrete component in order to engage a coupling part of the hoist. The head of the anchor is usually cast into the prefabricated concrete component in such a way that it lies in a recess provided in the prefabricated concrete component so that the anchor head does not protrude above the surface of the component. Transport anchors of this type are made from round or flat steel, with round steel transport anchors having a round head and foot that is upset to support the load. Anchors made of flat steel have a recess on the protruding head part, namely a hole for coupling the hoist. Its base, which is embedded in the concrete, is provided with a spreader in a common design to introduce the load into the concrete.

which is formed by cutting the sheet material in the base part and by bending the expansion legs created by the cutting in opposite directions. The manufacture of these anchors, which have been known for a long time, is, however, cross-sectionally dependent on the size of the section moments that occur, because depending on the load, the anchor must always have a sufficient cross-section to prevent the expansion legs from bending back under the effect of a load and thus tearing out the concreted anchor. It is therefore necessary when dimensioning such anchors with an expansion foot, to adhere to a minimum cross-section/in particular a minimum thickness specified for the intended load in order to counteract the risk of the anchor tearing out.

Round anchors with a widened base and flat anchors with bent expansion feet must also be cast into the precast concrete element with a load-dependent minimum installation depth. The greater the load to be absorbed, the deeper the base of the anchor must be anchored in the concrete element. In addition, the base with expansion attachments must be sufficiently deep when cast in concrete in order to create the greatest possible saddle load and thus a correspondingly large breakout cone in the concrete of the precast element. In addition, expansion anchors require a longer installation length from the outset, since the expansion of the base caused by separating the flat material impairs its strength, especially since the cut must be relatively deep in order to avoid excessive deformation of the expansion legs when bending.

For reasons of strength, it is also disadvantageous for thin precast concrete elements that both round anchors with a round expansion attachment in the foot and flat steel expansion anchors with offset, oppositely bent

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Expansion legs mean that the forces entering the precast concrete element via the anchor are not precisely directed into the concrete.

For thin precast concrete components, so-called two-hole anchors made of flat steel are also used, which are intended to ensure that the load is introduced deeper into the thin precast concrete component. The head part of such two-hole anchors is designed like round or flat anchors. In the foot part, on the other hand, there is a round or oval hole through which a so-called support iron is threaded before the concrete is cast in. This iron is located transversely to the longitudinal axis of the transport anchor and is intended to introduce the load forces into the depths of the precast concrete component on both sides over a relatively long path.

In order to be able to thread the additional iron quickly and easily before setting in concrete, the hole in the base of the two-hole anchor must have a sufficiently large amount of play. In addition, the additional iron must be long enough, namely up to 10 times the actual anchor length, to ensure secure anchoring. These requirements require a relatively high level of material and cost, especially since threading the additional iron separately requires an additional, relatively complicated work step.

The invention is based on the task of developing an anchor for precast concrete components of the type mentioned at the beginning in such a way that the forces to be introduced into the precast concrete component can be determined according to position and size and are optimally uniform and the anchor can be made shorter and thus more material-efficient compared to known anchors, in particular expansion anchors, of the same load level.

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and in which the saddle load of the concrete, which is effective on the expansion lugs located transversely to the anchor, can nevertheless be greater than with comparable known anchors, in which the saddle surfaces of the anchor provided on the expansion lugs can therefore be arranged comparatively deeper in the precast concrete component than with known expansion anchors, despite its shorter length.

According to the invention, this object is achieved in an expansion anchor of the type mentioned at the outset by the features of the characterizing part of claim 1.

The subclaims claim further advantageous embodiments as well as an alternative solution based on the same inventive concept.

Because, according to the invention, the expansion lugs are separate parts from the anchor with flat saddle surfaces that are held in a form-fitting manner in a recess in the anchor base, the actual anchor, consisting of the anchor base, anchor shaft and anchor head, and the expansion lugs can be manufactured in a simple and cost-effective manner, primarily by means of punching, pressing or forming, whereby the expansion lugs with their saddle surfaces can be optimally dimensioned and designed according to the shape, size and inclination to the longitudinal axis of the anchor in accordance with the stresses that occur. Since the anchor according to the invention is no longer tied to a minimum cross-section, in particular to a minimum thickness, like the known expansion anchor, less material is required for its manufacture than for the known expansion anchors of the same load level. The saddle surfaces of the expansion attachments can be designed so that the saddle surfaces are exactly symmetrical to the direction of the acting load force, since they are separate and no longer made by cutting into the anchor foot.

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Furthermore, since the expansion lugs are no longer bent, the risk of the expansion lugs falling back if the anchor is overloaded is also avoided.

The invention is explained in more detail below with reference to exemplary embodiments and the drawings. They show:

Fig. 2 for a round anchor in a known design,

Fig. 3 to 3b an anchor according to the invention, which consists of

flat steel, with Fig. 3 being a front view, Fig. 3a a side view and Fig. 3b a top view,

Fig. 4 the lower shaft and foot part of a

modified embodiment of an anchor made of flat material according to the invention,

Fig. 5 the anchor designed according to the invention according to Fig. 3, cast into a precast concrete component ,

Fig. 6, 6a another embodiment of an anchor according to the invention and 6b, which also consists of flat iron.

Fig. 1 shows a known flat iron anchor 1 with a head 3 and a receiving opening 3' for hanging a coupling part of the hoist, a shaft 4 and the foot 5. The foot 5 has spreading lugs 7 in the form of spread legs, which are bent apart after the foot has been cut. The foot with spreading lugs 7 is in a

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Precast concrete part 2 is encased in concrete; the surfaces facing the head 3 of the anchor form the saddle surfaces and the concrete mass located essentially above these saddle surfaces 6 is referred to as the break-out cone. The known round anchor design according to Fig. 2 is embedded in the relatively thin precast concrete component in such a way that the head 3 does not protrude beyond its upper edge ^21. The encased shaft 4 is followed by a round foot 5 which has expansion lugs 7 with saddle surfaces 6, 6' projecting laterally beyond the cross-section of the shaft. As a result of the round design of the foot part 5 with expansion lugs 7, identically designed expansion lugs with saddle surfaces are obtained in each longitudinal cross-section, so that the saddle load is distributed accordingly on all sides. When installed in relatively thin precast concrete elements, this has the disadvantage that the saddle forces enter the parallel longitudinal surfaces 2a of the precast concrete element over a relatively short distance. The lines shown show the relatively large breakout cone that occurs here and directly affects the side walls of the precast concrete element.

The embodiment of an anchor 1 according to the invention shown in Fig. 3 to 3b shows one made of flat iron. The anchor 1 has, in a known manner, an anchor head 3 with a receiving opening 3' for a coupling piece ψ of the lifting device, a shaft 4 and a foot 5 cast into the precast concrete part 2. In the foot 5 of the anchor there is a recess 8 in the form of a round hole, which is punched out of the flat material together with the recess 3 ^1. In this recess 8, cf. the embodiment according to Fig. 4, a part which is separate from the anchor 1 made of flat iron, namely a round bolt, is inserted, the expansion bolt projecting laterally beyond the cross section of the shaft 4.

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projections 7, 7 * with the flat, i.e., plain, saddle surfaces 6, 6 ¹ !or 6a, 6b in Fig. 4 pointing towards the anchor head 3 are formed in a pressing process after the round bolt has been inserted. The central section of the round bolt is mounted immovably in the recess 8 due to the wide, leaf-like design of the saddle surfaces 6, 6', whereby, in addition to the absolutely rigid connection between the round bolt and the foot 5 of the shaft, a deformation of the expansion projections 7, 7" or 7a, 7b can be provided in such a way that on both sides of the recess 8 a compressed, bead-like widening 15, 15' is formed in the form of annular projections 15 at least partially surrounding the recess 8.

As a result of this design, the expansion projections 7, 7 ^' protruding on both sides of the anchor foot 5 can be provided with saddle surfaces 6, 6', which in their geometric

shape and in its inclination to the longitudinal axis A-A i

in terms of the effective coupling forces, they can be designed in such a way that the position and size of the coupling forces and thus also the position and size of the breaking cone can be predetermined.

Advantageously, the sections of the spreading lugs 7, T (Fig. 3 to 3b) or 7a, 7b (Fig. 4) formed by the inserted round bolt which are opposite the saddle surfaces 6, 6' (Fig. 3 to 3b) or 6a, 6b (Fig. 4), i.e. which face the lower end of the foot 5 with its lower edge 10, i.e. the surfaces 9, 9' or 9a, 9b _f opposite the saddle surfaces 6, 6' or 6a, 6b can also be designed as flat surfaces, i.e. as plane surfaces i.

As can be seen from the drawings, it is advisable to arrange the saddle surfaces symmetrically to the longitudinal centre axis

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A-A of the anchor in order to obtain precisely defined, uniform stresses on both sides of the longitudinal axis A-A of the anchor 1.

The intended flat pressing of the protruding expansion lugs 7, 7 ¹ of the round bolt inserted into the bore 8 thus advantageously creates a precisely definable, flat and sufficiently wide saddle surface 6, 6' or 6a, 6b, which, depending on the design of the anchor, can be manufactured in such a way in terms of size and shape that the saddle forces can be predetermined, i.e. defined. In comparison to a known expansion anchor with bent expansion legs and in comparison to the known two-hole anchor with retracted, round cross-section additional irons, an anchor according to the invention thus results in a wider, larger saddle surface and thus a considerably lower surface pressure, whereby the transverse forces caused by the bending of the expansion legs and the rounding of the additional iron, which cannot be precisely calculated in terms of size and position, are avoided, whereby the rigid positive connection between anchor 1 and inserted round bolt with transversely projecting saddle surfaces 7, T has created an absolutely stable anchoring that can be predetermined with regard to the forces that occur, compared to a threaded additional iron.

The deformation according to the invention of the bolt inserted in the base part 5 of the anchor 1 to form expansion lugs 7, ⁷¹ with flat saddle surfaces also results in the advantage that in the area in which the greatest load is effective, i.e. immediately next to the reveal of the hole 8, the cross section of the bolt inserted is unchanged, so that at this point a maximum cross section and thus sufficient strength of the cross bolt against the stresses occurring at this point

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It is advantageous if the saddle surfaces 6, 6' or 6a, 6b run at an obtuse angle OC to the longitudinal center axis AA, since then the saddle forces , which act as normal forces perpendicular to the saddle surface, are distributed over a larger spatial area, i.e. over a larger concrete mass, so that the concrete, which is less subject to tension than to compression, is less stressed when the precast concrete part is lifted. The expansion lugs 7, 7 ^' or 7a, 7b, seen in section through the longitudinal center axis AA, can have approximately the shape of a right-angled triangle or an approximate trapezoidal shape, in such a way that the cross-section increases in the direction of the recess 8, so that the expansion lugs each have their largest cross-section directly in this area.

In the embodiment shown in Fig. 4, the saddle surfaces 6a and 6b are inclined at an angle OC to the longitudinal axis AA, which is greater than the angle oC of the embodiment of Fig. 3 to 3b. In comparison to known expansion anchors, the anchor according to the invention can thus be concreted into the precast concrete component with less installation depth while maintaining the same strength, so that the anchor according to the invention, particularly in the embodiment according to Fig. 4, can have an even shorter overall length compared to known anchors and thus a corresponding saving in material. The design of the anchor according to the invention is particularly advantageous for relatively narrow or thin precast concrete components, since the saddle forces that occur can be directed due to the definable position and shape of the saddle surfaces 6, 6' or 6a, 6b in such a way that they are essentially in the direction defined by the

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thus of a narrow precast concrete component, so that ! the stress on the side walls shown in Fig. 2 jj. of a narrow precast concrete component are largely avoided.

% In the embodiment shown in Fig. 4, the surfaces 9a, 9b of the expansion lugs 7a, 7b facing away from the saddle surfaces 6a, 6b are also inclined differently than the saddle surfaces 6a, 6b in that the angle ΔQ} is smaller than the angle ΔC between the axis AA and a surface line of the saddle surfaces 6a, 6b. This results in a favorable, almost trapezoidal cross-sectional profile of the expansion lugs 7a, 7b with relatively strongly inclined saddle surfaces 6a, 6b with the advantage that the anchor as a whole can be kept even shorter with the same load.

In Fig. 5, an anchor of the embodiment according to Figs. 3 to 3b is shown installed in a relatively thin precast concrete component 2, wherein the head 3 of the anchor is inserted into a corresponding recess in the precast concrete component in such a way that the edges 2', ²¹ are above the anchor head. In the base part 5 of the anchor there is the recess 8 in which the round bolt is inserted symmetrically to the anchor 1.

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1st, such that the expansion projections 7, T protruding from both sides of the anchor 1 with their saddle surfaces 6, 6' are of equal length. It can be seen that the saddle surfaces 6, 6" in the precast concrete part 2 have a precisely defined position and by a desired large inclination of the saddle surfaces the saddle forces are essentially in the area of the anchor and a correspondingly large break-up cone exists in the middle area of the precast concrete part. Because the saddle surfaces 6, 6 ¹

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or 6ä, 6b run at an angle away from the recess 8/ the expansion projections 7, 7' or 7a, 7b lying transversely to the anchor 1 are subjected to less bending stress than if the intended inclination of the saddle surfaces did not exist. A greater inclination of the saddle surfaces 6a, 6b as shown in Fig. 4 has the advantage that the height of the saddle load can be increased by the amount of the retraction of the saddle surfaces 6a, 6b, whereby with the same overall length of the anchor in comparison to the design according to Figs. 3 to 3b with the same length of the anchor, the effective installation depth is functionally increased.

Figures 6, 6a and 6b show another embodiment of the anchor according to the invention. Instead of a central hole 8 in the base part 5 of the anchor, the base is provided with groove-like recesses 8 ¹ , 8" at two opposite points, into which the expansion lugs 7c, 7d of a preferably square flat piece 11 are pressed in a form-fitting manner. The expansion lugs 7c, 7d are thus formed directly by the flat iron piece 11. The flat iron piece 11 advantageously has a recess 12 corresponding to the cross-section of the anchor base 5, with the material of this flat iron piece 11 projecting beyond the outer contour of the anchor base on all sides forming the saddle surfaces 6a _f 6d, 6e and 6f. In order to secure the flat iron piece 11 in an absolutely form-fitting manner in the groove-shaped, preferably rectangular recesses 8 ¹ , 8" on the opposite edges of the base 5, the two opposite middle sections 13, 13· are on the flat sides of the anchor 1 are deformed in an approximately V-shape towards the lower edge 10' of the anchor, whereby in order to achieve the symmetrical position of the saddle forces, the apex 14 of the deformed central section

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This results in an anchor which, like the embodiment according to Fig. 3 to 3b, also has the advantage of a definable saddle surface which, like the embodiment according to Fig. 3 to 3b, can be designed to be inclined downwards. Another advantage here _is that the saddle surfaces 6a, 6d and 6c as well as 6f, see Fig. 6b, surround the cross-section of the flat anchor 1 on all sides, so that the position and size of the saddle surfaces can be precisely predetermined depending on the load ratio.

The V-shaped deformation in the direction of the lower edge 10' of the anchor in the area of the two opposite middle sections 13 and 13· also has the advantage that the direction of the load force can be precisely specified by this design.

The saddle surfaces can be provided with an incline in the design according to Fig. 6 to 6b as well as in the design according to Fig. 3 to 3b, such that the saddle surfaces are directed in a preferred direction, namely perpendicular to the longitudinal center plane of the anchor. This makes it possible to ensure that the saddle forces, particularly in the case of narrow precast concrete components, run essentially parallel to the long sides of such a narrow component and that forces directed transversely to these long sides, which can lead to the precast concrete component breaking out sideways, are largely avoided.

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The manufacture of the anchor according to the invention, which in the preferred design consists of only two flat iron parts, is simple and inexpensive due to the low material requirements and the simple processing. Of course, it is expedient to provide the recess 8 or 8* with a sufficient distance from the lower edge or 10' so that the tensile forces occurring here can be absorbed with sufficient safety at the base of the anchor.

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Claims (1)

.!3.fimi'9!i. . W. to| stutigwi t..: Mr. A 38 314/bea &rgr; Siegfried Pricker Kurntoerger Str. 30-34 26JUH198S Wiernsheim Claims 1. Anchor for setting in concrete in heavy loads, such as precast concrete components, comprising an anchor head (3) provided with a recess (3 ¹ ) for coupling a lifting device, an anchor shaft (4) and an anchor foot (5) to be set in concrete in the precast concrete component (2), with spreading lugs (7) projecting laterally beyond the cross-section of the shaft (4) with saddle surfaces (6) for the load forces to be absorbed, in which at least the anchor foot (5) has a shape deviating from the circular cross-section, characterized in that the expansion lugs (7, 7'; 7a, 7b; 7c, 7d) are parts separate from the anchor (1) with flat saddle surfaces (6, 6"; 6a, 6b; 6c, 6d) which are fastened with positive locking in a recess (8; 8 ¹ ) located in the anchor foot (5). 2. Anchor according to claim 1, in which the anchor head, shaft and foot consist of flat iron, characterized in that the expansion lugs (7, 7'; i| 7a, 7b) are connected by a round bolt with the diameter the recess (8) are formed, which is held in a form-fitting manner with its central section in the recess (8) and whose spreading projections (7, 7 ¹ ; 7a, 7b) projecting on both sides of the anchor foot (5) form flat -2- s. &ogr;&trade;-> Saddle surfaces (6, 6 ¹ ; 6a, 6b) are deformed. 3. Anchor according to claim 1 or 2, characterized by a deformation of the expansion lugs (7, ^7e ; 7a, 7b), in which the round bolt for locking in the anchor (1) has a compressed, bead-like widening (15, 15') on both sides of the recess (8). 4. Anchor according to one of claims 1 to 3, characterized in that the surfaces (9, 9 ¹ or 9a, 9b) of the spreading lugs (7, 7'; 7a, 7b; 7c, 7d) opposite the saddle surfaces (6, 6 ¹ ; 6a, 6b; 6c, 6d) are designed as flat surfaces. 5. Anchor according to one of claims 1 to 4, characterized in that the saddle surfaces (6, 6'; 6a, 6b; 6c, 6d) are arranged symmetrically to the longitudinal center axis (A-A) of the anchor (1). 6. Anchor according to one of claims 1 to 5, characterized in that the saddle surfaces (6, 6a, 6b) are inclined at an obtuse angle (OC) to the longitudinal center axis (A-A). 7. Anchor according to one of claims 1 to 6, characterized in that the expansion lugs (7, 7'; 7a, 7b) have approximately the shape of a right-angled triangle or an approximate trapezoidal shape when viewed in section through the longitudinal center axis (A-A). 6. Anchor according to one of claims 1 to 7, characterized in that, in addition to the saddle surfaces (6a, 6b; Fig. 4), the surfaces facing away from them (9a, 9b) form an obtuse angle (OCM) with the central axis (A-A) il ti t» f« t I I I I t t * · ttt II ti« I · 1 · · < I Hl ti ·! »itt ·«! ti 11 «II · · I I Ut tt ti · which is smaller than the angle (CC) between the axis (A-A) and the associated saddle surfaces (6a, 6b). 9. Anchor according to one of claims 1 to 8, characterized in that the saddle surfaces (6, 6') are widened outwards, preferably approximately leaf-like (Fig. 3b). 10. Anchor according to one of claims 1 to 9, characterized in that the recess (8, 8') is arranged at a sufficient distance from the lower edge (10) of the anchor (1). If 1. Anchor according to one of claims 1, 4 or 5, characterized in that the foot (5) of the anchor (1) has groove-like recesses (8', 8") at at least two opposite locations, into which expansion lugs (7c, 7d) are pressed in a form-fitting manner. 12. Anchor according to claim 11, characterized in that the spreading lugs (7c, 7d) are formed by a flat iron piece (11) (Fig. 6). 13. Anchor according to claim 11 or 12, wherein the anchor consists of a flat iron, characterized in that the flat iron piece (11) has a recess (12) corresponding to the cross section of the anchor foot (5), and that the material of the flat iron piece (11) projecting on all sides beyond the outer contours of the anchor foot forms saddle surfaces (6a, 6d; 6e, 6£) (Fig. 6b). «# »44* »4 i &igr;« ,t | i » I « » <A &iacgr; til ti. Ht · 4 «·! · 111 «I <*» leea tt» it it &igr; 14. Anchor according to one of claims 11 to 13, characterized in that for the positive anchoring of the flat iron piece (11) in the groove-shaped edge recesses (8 ¹ , 8 ⁿ ) its middle sections (13, 13') are deformed approximately V-shaped towards the lower edge (10·) of the anchor (1). 15. Anchor according to one of claims 11 to 14, characterized in that the apex (14) of the deformed central sections (13, 13') lies in the longitudinal central axis (A-A) of the anchor (1) (Fig. 6). 16. Anchor according to one of claims 1 to 15, characterized in that the anchor and the expansion attachments consist of separate, preferably rectangular flat iron and are finally manufactured by means of punching, pressing or forming.