EP3851616B1 - Transport anchor with strap - Google Patents

Description

The invention relates to a transport anchor, in particular for hollow walls or double or multiple concrete walls, each with opposing concrete shells according to claim 1. The invention also relates to a method for producing such a transport anchor according to claim 9.

It is, for example, from the product catalogue Bohr Gmbh: "Build something great", October 31, 2019 (2019-10-31), pages 1-195 or the one not yet published DE 10 2018 117 625 the same applicant known to use transport anchor (filigree anchor) for transporting and moving double walls. The transport anchor essentially comprises a clevis and a crossbar or a cross brace. The parallel, opposite ends of the load bracket serve as anchoring legs for embedding in concrete in a concrete shell. They are connected to one another by a center section of the yoke that is generally curved once or several times and are held apart or at a predetermined distance from one another by the cross brace. This is to prevent the anchoring legs from contracting and tearing out of the concrete shells when the wall is lifted. The cross brace is attached to the anchoring legs in a movable, displaceable manner or by means of welded connections or tacking, with the entire lifting bracket of the transport anchor being stiffened. A clevis comprising a clevis center section and the anchoring legs of the lifting anchor is often provided by bending rebar using a bending machine. A problem with such a manufacturing process is that the rebars used as the starting material are not always the same. Tolerances of the rebar exist with regard to the strength, the dimensions, in particular the diameter, the roundness and the dimensions of the ribs of the rebar. If these rebars are then processed into lifting anchors, each bent lifting anchor can have different external dimensions when measured afterwards. These deviations are amplified by manufacturing tolerances of the bending machine and temperature differences in the steel.

The distance between the two anchoring legs is particularly affected by these deviations, since the loose anchoring legs can easily be bent during production, storage, transport or installation of the lifting anchor in the precast concrete plant. These deviations in the outer dimensions of the lifting anchor are undesirable and problematic for installation and operational safety.

If, for example, the anchoring legs are further conically bent, i.e. the lifting anchor becomes wider towards the anchoring leg end sections, the concrete cover on the outside of the concrete double wall falls below the required minimum thickness. This can result in rust damage to the transport anchor. According to the installation instructions, the anchoring legs require a concrete cover of 10mm. Even a slight bending up of the anchoring leg, which results in a 1 mm increase in the distance between the end sections of the anchoring leg, reduces the concrete cover by a full 10%. If, on the other hand, the anchoring limbs are pressed together, the transport anchor becomes narrower towards the anchoring limb end sections and the distance between the anchoring limb end sections can be less than the length of the cross brace. Then there is a risk that the anchoring leg does not dip deep enough into the reinforcement cage and is consequently not anchored deep enough in the concrete. As a result, when transporting the double wall, there is a possibility that the transport anchor will not safely bear the load of the component and will tear out.

In the prior art, for example DE 10 2017 102 903 A1 from the same applicant, the lifting anchors for concrete double walls also have an additional cross brace on the anchoring leg end sections, which is welded to the anchoring legs in the area of the anchoring leg end sections.

the DE 10 2016 119352 A1 provides a lifting anchor with a where the cross brace is concrete. Finally, a fixing element can connect the anchor legs to one another, preferably by welding. This fixing element enables the anchoring legs to be shortened or prevents them from floating up.

The object of the invention is to improve the operational safety of the known transport anchor and to reduce the risk of errors during installation.

The lifting anchor specified in claim 1 and the manufacturing method specified in claim 9 for lifting anchors with a cross brace are proposed as a solution. Optional refinements of the invention result from the dependent claims.

• Einen Lastbügel mit mindestens zwei Verankerungsschenkeln, wobei mindestens ein Verankerungsschenkel je einer Betonschale oder Betonwand zuordenbar ist.
• Einen Lastbügel-Mittelabschnitt, über welchen die mindestens zwei Verankerungsschenkel miteinander verbunden sind, wobei mit dem Lastbügel-Mittelabschnitt externe Lastaufnahme- und/oder Transportmittel koppelbar oder in Eingriff bringbar sind.
• Mindestens eine Querstrebe oder sonstige Abstandhalteeinrichtung, welche zur Aufnahme von Druck- oder Zugbelastungen zwischen den Verankerungsschenkeln quer oder schräg bezüglich einer Längsrichtung des oder der Verankerungsschenkel oder einer Körperachse des Transportankers angeordnet ist.
• Mindestens eine erste Halteeinrichtung, wobei die erste Halteeinrichtung die mindestens zwei Verankerungsschenkel, vorzugsweise lösbar, umfasst.

The invention relates to a transport anchor according to claim 1, in particular for cavity walls or double or multiple concrete walls, each with opposing concrete shells, the transport anchor having the following:

• A clevis with at least two anchoring legs, with at least one anchoring leg being assignable to a concrete shell or concrete wall.
• A central section of the shackle, via which the at least two anchoring legs are connected to one another, with external load handling and/or transport means being able to be coupled or engaged with the central section of the shackle.
• At least one transverse strut or other spacer device, which is arranged transversely or obliquely with respect to a longitudinal direction of the anchoring leg(s) or a body axis of the transport anchor to absorb pressure or tensile loads between the anchoring legs.
• At least one first holding device, wherein the first holding device comprises the at least two anchoring legs, preferably in a detachable manner.

To make things easier to understand, a lifting anchor with two anchoring legs, which connects two concrete shells of a double wall, is usually assumed below. A clevis typically has two anchoring legs, with one anchoring leg each being cast or capable of being cast for casting in a concrete shell or concrete wall of a double wall. The clevis center section is preferably located in a space between the opposing concrete shells. The crossbar can also be arranged in this intermediate space and absorbs the pressure and/or tensile forces when lifting or erecting the double wall on the transport anchor and thus stabilizes the transport anchor when the load is picked up. At the same time, the cross brace can be designed as a spacer device or other device for maintaining the distance between the anchoring legs. It is slidably or fixedly connected to the clevis and, in particular, keeps the anchoring legs of the clevis relative to one another at an exact distance that was set when the transport anchor was manufactured. A holding device, which also includes the anchoring legs of the transport anchor at at least two contact points, additionally stabilizes the individual sections of the load bracket and the cross brace in the load bracket. The desired shape of the lifting anchor set during manufacture can also be maintained during storage and installation, in particular through the interaction of the cross brace and holding device. This simplifies handling when installing the transport anchor in the double wall to be manufactured and increases installation safety. Releasable fastening means that the holding device can be removed without being destroyed before, after and/or during installation, or at least loses its holding power as a result of being destroyed.

The holding device preferably comprises or encompasses an anchoring leg assigned to a first concrete shell and an anchoring leg assigned to a second concrete shell.

Encompassing means that the holding device forms a form-fitting and/or frictional and/or material-locking holding connection with both anchoring legs, so that the anchoring legs are locked and fixed in a predetermined position relative to one another for installation. In this way, in particular in the interaction of the holding connection with the cross brace, it is prevented that the one clevis width specified for operational safety is not exceeded in the area of the anchoring legs. The required concrete cover on the outside of the double wall can thus be maintained and rust damage to the lifting anchor can be avoided. Furthermore, it is prevented that the distance between the anchoring legs falls below a predetermined value. As a result, a concrete cover is maintained in the space between the double wall and the anchoring legs are prevented from being torn out when the double wall is lifted or erected.

In a preferred embodiment of the invention, the holding device forms a frictional holding contact with the anchoring leg assigned to the first concrete shell and/or the anchoring leg assigned to the second concrete shell.

In the finished transport anchor, it is provided that the anchoring legs run essentially parallel. Nevertheless, during the manufacture of the clevis when pre-bending an extruded body, provision can initially be made for the anchoring legs to run more or less conically in relation to one another and open towards the anchoring leg end sections. In other words, the distance between the anchoring legs increases starting from the transition curves towards the leg end sections. After inserting and possibly fastening the cross brace, the anchoring leg end sections are pressed inwards, ie towards the body axis, so that the anchoring legs align parallel to one another or close towards the anchoring leg end sections. This creates a pretension in the load bracket, which can be permanently maintained for transport and/or installation by the frictional holding contacts of the holding device. Alternatively, the anchoring limbs are pressed further outwards by a suitable holding device, so that the distance between the anchoring limb end sections increases further. In this case, the preload can be maintained, for example, by a holding device (see Fig.2a ) which encompasses or surrounds the cross brace and the clevis middle section.

According to the invention, the holding device is designed as a band-like, preferably flexible and/or taut, holding band, for example a packaging band.

The retaining strap is wrapped around the load bracket in the area of the anchoring legs at least once so that the anchoring legs are gripped from behind. The tether comes to rest with the anchoring limbs on the area of the anchoring limbs facing away from the body axis and maintains a pretension in the clevis which may be necessary for the desired alignment of the anchoring limbs. The retaining strap can be designed as an inexpensive packaging strap, which can be removed by cutting at any installation step.

The anchoring limbs, in particular the anchoring limb end sections, are preferably fixed and/or locked by the holding device in a predetermined position of the anchoring limbs relative to one another.

A predetermined position means that, in particular in the area of the anchoring leg end sections, the width is neither exceeded nor fallen below a predetermined load bracket. This ensures that the penetration depth of the anchoring leg end sections into the concrete body of the concrete shell is maximum or corresponds to the desired amount. In particular, it is avoided that the anchoring leg distances in the area of the anchoring leg end sections are smaller than in the area of the cross brace or the transition curves and thus the transport anchor legs are not anchored deep enough in the concrete. The anchoring leg end sections remain precisely positioned by the holding device and the transport anchors can safely carry the load of the component.

In a preferred embodiment of the invention, the cross brace or other spacer device is attached to the anchoring leg or legs in a sliding manner and/or in frictional engagement.

This simplifies the connection or coupling of the cross brace to the anchoring legs, in that the string body of the anchoring leg is gripped by the cross brace by means of an axial sliding guide (i.e. in the longitudinal direction of the string body or anchoring leg) in the end regions of the cross brace with frictional engagement or static friction. A lateral or radial shifting or shifting of the extruded body is prevented by the opposing form fit within the sliding guide, which runs through the cross strut in its end regions, preferably transversely to its longitudinal direction. There is no longer any need for relatively complex welded joints or other materially bonded joints. For further features for the formation of a slidable cross brace and for their arrangement, reference is made to the not yet published application (file number: 10 2018 117 625.2 ) of the same applicant.

In an optional development, a transition curve is formed between the middle section of the shackle and the at least two anchoring legs, with the cross brace in the area of the transition curves passing through a second holding device, in particular by a second holding strap, is held, the first holding device spanning the at least two anchoring legs in the region of the anchoring leg end sections.

In the case of known lifting anchors, the anchoring legs usually transition into the middle section of the lifting anchor clevis via a transition curve, transition bend or transition kink. In combination with this, within the scope of an optional embodiment of the invention, the cross brace is positioned in such a way that it adjoins, abuts or bears against the curved transition area of the middle section of the yoke. So that there is no need for welding or any other joining method for a non-detachable connection, the position of the cross brace is fixed by compressive forces which are exerted by both anchoring legs on the two end regions of the cross brace, with the compressive forces being essentially parallel to the longitudinal axis of the cross brace and perpendicular facing the anchoring legs. The compressive force is provided by both anchoring legs being pressed in the direction of the body axis of the transport anchor and the resultant tensioning force or prestressing in the strand body of the load clip being permanently fixed by a holding device in the area of the anchoring leg end sections until the holding device is removed or destroyed. The first holding device is a holding strap that encircles the two anchoring legs, i.e. grasps around or behind them, and can prevent the pretension generated in the clevis from loosening again.

• Bereitstellen eines Lastbügel-Strangkörpers, vorzugsweise aus Betonrippenstahl, zur Herstellung des Lastbügels,
• Biegen oder Vorbiegen des Lastbügel-Strangkörpers zum Herstellen eines Lastbügels oder eines Lastbügelrohlings mit einer etwa U-förmigen Grundform unter Ausbildung von zwei Verankerungsschenkeln, einem zwischen den beiden Verankerungsschenkeln angeordneten Lastbügel-Mittelabschnitt und zwischen dem Lastbügel-Mittelabschnitt und den beiden Verankerungsschenkeln angeordneten Übergangskrümmungen,
• Einsetzen einer Querstrebe zwischen die Verankerungsschenkel, insbesondere zwischen die Übergangskrümmungen,
• Spannen eines ersten Haltebands oder einer sonstigen, vorzugsweise strangartigen, Halteeinrichtung, zur Lage-Festlegung der Verankerungsschenkel.

Independent invention protection is claimed for a method according to claim 9 for producing a lifting anchor, in particular a lifting anchor in one of the described embodiments. The procedure is characterized by the following steps:

• Provision of a shackle string body, preferably made of rebar, for the production of the shackle,
• Bending or pre-bending the shackle string body to produce a shackle or a shackle blank with an approximately U-shaped basic shape while forming two anchoring legs, a shackle middle section arranged between the two anchoring legs and transition curves arranged between the middle section of the clevis and the two anchoring legs,
• Insertion of a cross brace between the anchoring legs, in particular between the transition bends,
• Tensioning of a first retaining strap or another, preferably strand-like, retaining device to fix the position of the anchoring legs.

By attaching the tether in a late and/or final manufacturing step, manufacturing tolerances when bending and/or pre-bending the extruded body and inserting the cross brace can be compensated for, which simplifies manufacturing and increases the quality of the lifting anchor manufactured with it. The cross brace can be held in the yoke by frictional retaining contacts and/or joining methods such as welding. Preferably, after or during the insertion of the cross strut, a second retaining strap or other retaining device is tensioned to fix the position of the cross strut in contact with the cross strut and the clevis blank and/or the clevis.

The cross brace is held in a predetermined position, preferably in the region of the transition curves, by the second retaining strap. As a result, additional joining methods for fastening the cross brace can be omitted. The tensioning force of the retaining strap resulting from the tensioning process presses the cross brace in the area of the transition curves against the middle section of the yoke. This creates a holding force of the transition curves on the cross brace, which prevents the cross brace from slipping sideways or radially in the transport anchor.

• vor oder während dem Spannen eines ersten Haltebands oder einer sonstigen Halteeinrichtung die beiden Verankerungsschenkel unter Ausbildung einer Vorspannung in dem Lastbügelrohling in eine, vorzugsweise reibschlüssige, Anlage mit der Querstrebe bewegt werden und
• zur Lage-Festlegung der Verankerungsschenkel in dieser Anlage das erste Halteband um die Verankerungsschenkel gespannt wird.

The method according to the invention has the further steps that

• before or during the tensioning of a first retaining strap or other retaining device, the two anchoring legs are moved into a, preferably frictionally engaged, contact with the transverse strut while forming a pretension in the load bar blank and
• to determine the position of the anchoring leg in this system, the first retaining strap is stretched around the anchoring leg.

The frictional contact is preferably realized at two contact points between the two end areas of the cross brace and the anchoring legs, in particular in the area of the transition curves, that is to say in the straight area of the attachment triangle for the attachment means. Since the blank clevis has previously been manufactured in such a way that the distance between the anchoring legs increases towards the end sections of the anchoring limbs, the realization of the contact contacts results in a pretension in the clevis. This pretension can be fixed, for example, by tightly wrapping the load bracket in the area of the anchoring leg with a packing tape.

• Figur 1 und 2a den Transportanker in je einer beispielhaften Ausführungsform aus dem Stand der Technik in einer perspektivischen Ansicht;
• Figuren 2b-2c den Transportanker in zwei beispielhaften erfindungsgemäßen Ausführungsformen in einer perspektivischen Ansicht.

Further details, features and effects based on the invention result from the following description of three exemplary embodiments of the invention and from the drawings. The drawings show in:

• figure 1 and 2a the transport anchor in an exemplary embodiment from the prior art in a perspective view;
• Figures 2b-2c the transport anchor in two exemplary embodiments according to the invention in a perspective view.

The figures are merely of an exemplary nature and serve only to understand the invention. The same elements are provided with the same reference numbers.

figure 1 shows a transport anchor from the prior art with a clevis 100 made of highly ductile rebar, and a cross brace 200 made of a steel tube that is pressed flat in its end areas 201 . In the case of the one-piece yoke 100 with an approximately U-shaped basic shape, its rectilinear, parallel, opposite end sections each form an anchoring leg 101, which merges into a central section 103 of the yoke via a transition curve 102 in each case. The yoke middle section 103 connects the two anchoring legs 101, with the yoke middle section 103 external load bearing and/or means of transport, for example crane hooks (not shown), can be coupled or engaged. A body axis 107 of the transport anchor can essentially correspond to an axis of symmetry of the transport anchor, the clevis 100 and/or a mirror axis between the anchor legs 101 . The ends of the anchoring legs 101 facing away from the central section 103 of the yoke, the end sections 104 of the anchoring limbs, run parallel to one another, so that the width 105 of the yoke in the area of the end sections of the anchoring limb 104 corresponds to the width of the yoke 105 in the area of the transition curve 102. A predetermined anchoring leg distance 106, ie the distance between the anchoring legs 101, should not be undershot. The cross strut 200 is designed in its end areas 201 at the same time with guide recesses 202, in which the respective ribbed steel strand body of the anchoring leg 101 is accommodated with frictional engagement and slidingly displaceable against a frictional force. In the figure 1 The arrangement shown is further provided with a holding device 300 in the form of a relatively wide packaging tape 301a, which is wrapped around the middle part of the yoke center section 103 and around a cross brace middle section 203 in order to hold the cross brace 200 and the clevis 100 in a certain relative position to one another. The wide side of the packaging tape that is visible to the outside can be used as an information carrier for the reproduction of various information 303 .

Figure 2a shows a lifting anchor, in contrast to the lifting anchor according to FIG figure 1 the packaging tape or the retaining tape 301 is wound with tension around the middle part of the middle section 103 of the bracket and around the middle section of the cross brace 203, so that a frictional holding contact 304 is formed with the cross brace 200 and a frictional holding contact is formed with the middle section of the load bow 103 and the cross brace 200 in the region of the transition curves 102, a frictional contact 150 with the load bracket 100 is realized. The frictional contact 150 also contributes to keeping the anchoring legs 101 of the load clip 100 in a specific position relative to one another.

Figure 2b shows a transport anchor with a first retaining strap 302 in the area of the anchoring limbs 101, in particular in the area of the anchoring limb end sections 104. During the manufacture of the clevis 100 when pre-bending an extruded body, the anchoring legs 101 are preferably initially aligned in such a way that the distance 106 between the anchoring legs 101 increases, starting from the transition curves 102 towards the end sections 104 of the legs. After inserting the cross brace 200, the anchoring leg end sections 104 are pressed inwards, ie towards the body axis 107, so that the anchoring legs 101 run parallel and contact contacts 150 are formed between the cross brace 200 and the transition curves 102. This creates a pretension in the yoke 101, which can be permanently maintained by the frictional holding contacts 304 of the holding device 300 for transport and/or installation. The first tether 302 is wound tightly at least once around the clevis 100 on the outside in the area of the anchoring legs 101, so that the anchoring legs 101 are gripped from behind. The tether 302 forms holding contacts 304 on a region of the respective anchoring leg 101 facing away from the body axis 107 and maintains the pretension in the clevis 100 , the pretension being necessary for the anchoring limb 101 to rest 150 on the cross brace 200 .

Figure 2c combines the tether 301 out Figure 2a and the first tether 302 off Figure 2b . By attaching the second tether 301, the subsequent assembly of the first tether 302 is facilitated, in particular for a manual assembly of the first tether 302. A total of four friction-locking holding contacts 304 are provided by two holding straps 301, 302, which hold the transport anchor in the desired position and ensure installation in accordance with the installation instructions. Instead of packaging tapes, for example, adhesive tapes can also be used. In addition, retaining straps 301, 302 can also be tightened in the transport anchor.

Reference List

100

load bracket

101

anchoring legs

102

transition curvature

103

Central section of the shackle or central section of the shackle

104

anchor leg end sections

105

yoke width

106

anchor leg spacing

107

Body axis, in particular axis of symmetry

150

System, in particular frictional system contact

200

cross brace

201

End area, especially flattened

202

guide recess

203

Crossbar center section

300

holding device

301

Second retaining strap, in particular packaging strap

302

First retaining strap, in particular packaging strap

303

information

304

Retaining contact, in particular frictionally

Claims (11)

1. A transportation anchor, in particular for hollow walls or double or multiple concrete walls, each with opposing concrete shells, wherein the transportation anchor has the following:

   - a clevis (100) with at least two anchoring limbs (101), wherein at least one anchoring limb (101) can be assigned to a concrete shell or concrete wall,

   - a clevis centre section (103), via which the at least two anchoring limbs (101) are connected to one another, wherein external load-bearing and/or transport means can be coupled to or brought into engagement with the clevis centre section (103),

   - at least one stabiliser bar (200) or other spacer device, which is arranged to absorb pressure or tensile stresses between the anchoring limbs (101), transverse or inclined in respect of a longitudinal axis of the anchoring limb(s) (101) or a body axis (107) of the transportation anchor,

   - at least one first holding device (300) which is formed as a ribbon-shaped strap (302),

   characterised in that
   the first strap (302) comprises the at least two anchoring limbs (101).
2. The transportation anchor according to claim 1,
   characterised in that
   at least one second holding device (300) is formed as a ribbon-shaped second strap (301) and comprises the clevis centre section (103) and the stabiliser bar (200).
3. The transportation anchor according to one of claims 1 or 2,
   characterised in that
   the strap(s) (301, 302) is (are) formed to be flexible or taut.
4. The transportation anchor according to one of the preceding claims,
   characterised in that
   the first strap (302) comprises an anchoring limb (101) which can be assigned to a first concrete shell and an anchoring limb (101) which can be assigned to a second concrete shell.
5. The transportation anchor according to the preceding claim,
   characterised in that
   the first strap (302) forms a friction-locked holding contact (304) with the anchoring limb (101) which can be assigned to the first concrete shell and the anchoring limb (101) which can be assigned to the second concrete shell.
6. The transportation anchor according to one of the preceding claims,
   characterised in that
   the anchoring limbs (101), in particular the anchoring limb end sections (104), are fixed and/or locked in a predetermined position relative to one another by the first strap (302).
7. The transportation anchor according to one of the preceding claims,
   characterised in that
   the stabiliser bar (200) or other spacer device is attached to the anchoring limb(s) (101) in a manner which can be displaced in sliding motion, and/or in friction-locking attachment (150).
8. The transportation anchor according to claim 7,
   characterised in that
   a transition curve (102) is formed between the clevis centre section (103) and the at least two anchoring limbs (101) respectively, wherein the stabiliser bar (200) is held in the region of the transition curves (102) by the first strap (302), wherein the first strap spans the at least two anchoring limbs (101) in the region of the anchoring limb end sections (104).
9. A method for producing a transportation anchor, in particular a transportation anchor according to one of claims 1-8,
   with the following steps:

   - providing a clevis strand body, preferably made of concrete ribbed steel, for producing the clevis (100),

   - bending, or pre-bending, the clevis strand body to produce a clevis (100) or a clevis blank with an approximately U-shaped basic form, forming

   ∘ at least two anchoring limbs (101),

   ∘ a clevis centre section (103) arranged between the two anchoring limbs (101), and

   ∘ transition curves (102) arranged between the clevis centre section (103) and the two anchoring limbs (101),

   - inserting a stabiliser bar (200) between the anchoring limbs (101), in particular between the transition curves (102),

   - tensioning a first strap (302) to fix the position of the anchoring limbs (101), wherein,

   ∘ before or during tensioning of the first strap (302), the two anchoring limbs (101) are moved into an attachment (150) with the stabiliser bar (200) by forming a pretension in the clevis blank,

   ∘ to fix the position of the anchoring limbs (101) in this attachment (150), the first strap (302) is tensioned about the anchoring limbs (101).
10. The method according to claim 9,
    characterised in that
    the attachment (150) between clevis blank and stabiliser bars (200) is friction-locked.
11. The method according to one of claims 9 or 10,
    characterised in that
    after inserting the stabiliser bars (200), a second strap (301) or any holding device (300) is tensioned with the stabiliser bar (200) and the clevis blank or the clevis (100) to fix the position of the stabiliser bars (200) in the attachment (304).

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