EP3569795B1 - Device for positioning a transport anchor - Google Patents

Description

The present invention relates to a combination of a lifting anchor and a device for positioning the lifting anchor in a formwork for a precast concrete part, the lifting anchor having an elongate anchor section which defines a longitudinal axis and a connecting section adjoining one end of the anchor section in the direction of the longitudinal axis , wherein the connecting section is a threaded section, the axis of which coincides with the longitudinal axis of the anchor section, the device having a recess body which can be connected in a sealed manner to the connecting section on one side and can be connected in a sealed manner directly to the inner wall of a formwork on a side remote from the connecting section is.

The invention also relates to a method for positioning lifting anchors in formwork for precast concrete parts and also precast concrete parts equipped with correspondingly positioned lifting anchors.

Devices for positioning transport anchors in formwork are known, for example, as so-called "nail plates". Such a known nailing plate typically has two parallel side faces, one of the side faces being provided with a projection for tight connection to the connecting section of a transport anchor. The attachment on the nailing plate is connected to the connecting section of a lifting anchor in such a way that the lifting anchor extends perpendicularly from one of the corresponding inner surfaces of the nailing plate into the interior of the formwork. This nail plate is then arranged with the opposite side on the inside of a formwork, namely where you want to have access to the lifting anchor in a precast concrete part, and fixed to the formwork.

For this purpose, the essentially plate-shaped plate is nailed to the formwork, for example. The lifting anchor then extends essentially perpendicularly to the inner surface of the formwork into the space that is later filled with concrete material. After the concrete has hardened and the formwork has been removed, the nailing plate is also torn off or removed separately if it is exposed on an outer surface of the precast concrete element. The connecting section of the lifting anchor, which was previously connected to the corresponding attachment on the nailing plate, is then accessible from the outside, so that appropriate attachment means for transporting the precast concrete part can be attached to the connecting section. The connecting section can take various forms and is designed, for example, as a ball head or as a sleeve with an internal thread, but could also be a threaded bolt with an external thread or some other connecting element. The anchor part is firmly connected to one end of the connecting section and consists, for example, of one or more wire rope sections or a wire rope loop. in all cases the anchor part is deliberately designed as an elongate element which can extend appropriately deep into the concrete and which defines a corresponding longitudinal axis. Instead of a wire rope, the transport anchor could also have a piece of reinforcing steel with a connecting sleeve or ball head attached to one end.

A precast concrete part, such as a wall element, usually has two such lifting anchors along an edge surface on either side of a center of gravity plane of the precast part and at a distance from one another. The distance between the transport anchors should prevent the precast concrete element from rocking and/or rotating on the crane hook. A threaded pin which is provided with a lifting eyelet or is attached directly to a suspension cable is then screwed into the threaded section of each of the transport anchors or, if the threaded section is an external thread, screwed onto it. In the case of eyelets, a transport rope is then attached so that a crane or crane hook connected to the rope can lift the precast concrete part.

In order to avoid an unnecessary length of the transport ropes, which could cause excessive vibrations and would also unnecessarily limit the available lifting height of a crane, the rope or ropes with which the connecting sections are connected to a crane hook via stops or eyes are as short as possible, which, with two lifting anchors simultaneously connected to the crane hook, leads to a corresponding deflection of the cable or cables relative to the relevant edge surface of the precast concrete part and relative to the longitudinal direction of the lifting anchor, depending on the distance between these lifting anchors.

As a result, in addition to the vertical load, transverse forces, ie forces acting transversely to the axis of the transport anchor, are transmitted from the support cable to the transport anchor, which in turn can lead to a partial breakout of the concrete surrounding the connecting section and impairs the load-bearing capacity of the transport anchor. The permissible pulling angles of the support cables relative to the surface of the finished part and also relative to the axis of the connecting section are therefore limited. Additional measures to avoid partial concrete failure, such as strengthening the concrete by inserting stirrups made of reinforcing steel with direct contact to the anchor, are otherwise absolutely necessary. Transport anchors are allowed on the Concrete parts should also not be arranged too close together, because otherwise the precast concrete part could very easily turn or deform and vibrate when it is hanging on the crane hook.

In practice, it can hardly be avoided that the transport ropes act at an angle relative to the surface of a precast concrete part that deviates significantly from the axis of the anchor section, which conventionally extends perpendicularly to the concrete surface, typically by a value of up to approx .30°.

From the DE 23 39 265 a formwork arrangement is known for the production of an end formwork surface of a prestressed concrete body that adapts to the end faces of the stressing anchors of prestressed concrete reinforcements, comprising a formwork wall and a formwork body arrangement fastened to the concrete side of the formwork wall and adjustable relative to this and the end face of the stressing anchors, the formwork body arrangement being formed by two formwork bodies, the first of which in the installed position bears against the formwork wall with a flat sliding surface and on the opposite side has a sliding surface which is not parallel to the formwork wall, and the second of which has a sliding surface which cooperates with this sliding surface on one side and a flat non-parallel to the sliding surface Surface is provided on the concrete side facing away from the first formwork body, the first formwork body being rotatable relative to the formwork wall at least during the assembly process and the second formwork ngskörper at least during the assembly process according to the shape of the mutually adjacent sliding surfaces of the formwork body is displaceable or rotatable relative to the first formwork body.

In addition, from the U.S. 4,443,980 a recess body known with a base body and a cover, wherein the recess body allows an inclined mounting of a lifting anchor in relation to a surface of the precast concrete part.

The present invention is defined by claim 1 and, compared to this prior art, has set itself the goal of positioning lifting anchors in a precast concrete part in such a way that the transverse forces acting on the lifting anchor or its connecting section are significantly reduced and therefore wants a correspondingly improved device for Positioning of lifting anchors in a formwork for precast concrete parts and thus providing better positioning of the lifting anchors in the precast concrete parts.

With regard to the combination mentioned at the outset, this object is achieved in that the recess body has two flat surfaces lying opposite one another the two surfaces are inclined towards one another and are connected to one another by a circumferential edge surface, with the circumferential edge surface forming part of a rotationally symmetrical surface, with a threaded connector fitting the threaded section in the form of a threaded bolt with an external thread or a threaded sleeve with an internal thread being perpendicular to the recess body to the surface facing the threaded section and along an axis of the rotationally symmetrical surface formed by the edge surface, so that when the recess body is aligned in the assembly position, the longitudinal axis of the anchor section is at an angle of less than 90° to the surface of the recess body that is to be tightly connected to a formwork wall runs inclined, wherein the threaded connector has a thread axis, wherein the rotationally symmetrical surface has an axis of symmetry and the thread axis is equal to the axis of symmetry.

The axis of the anchor section, the longitudinal direction or axis of the transport anchor and the axis of a threaded section of the transport anchor are identical or coincide and are used synonymously here.

In the context of the present invention, the connection between the individual elements is referred to as tight if it is tight with respect to concrete or concrete laitance. There is a higher tightness requirement for the connection between the recess former and the connecting section of the transport anchor than for the connection of the recess former with the formwork wall, in which case the ingress of some cement laitance between the recess former and the inside of the formwork would not be a problem. However, a ball head or the thread of a threaded section should be protected from any contamination and exposure to concrete or concrete slurry in order to ensure a safe and functional connection with a lifting device.

Due to the inclination of the connecting section connected to the recess former, the device can be arranged within a precast concrete part in such a way that one of the surfaces of the recess former is tightly connected to the inside of the formwork or to another recess former located in between, while the anchor sections of adjacent transport anchors of a precast concrete element are inclined towards one another. i.e. that the axes of the anchor sections each run inclined in the direction of the other, adjacent transport anchor.

If both lifting anchors of the finished concrete part are then suspended from the same crane hook either with a continuous rope or via two separate ropes, the direction of pull of these ropes deviates from the direction of the axis of the lifting anchor by a smaller angle than in relation to a perpendicular to the concrete surface in question corresponds to the direction of the axis of the anchor section in conventionally installed lifting anchors. Specifically, the angle between the pulling direction of the transport rope with respect to the axial direction of the anchor portion is reduced by the inclination angle of the transport anchor adjusted by the transport anchor positioning device according to the present invention, compared to a standard arrangement of the transport anchor. The angle relative to the surface of the precast concrete part should be between 50° and 85°, preferably between 70° and 80° and in particular around 75°. Accordingly, the inclination of the axis of the anchor section relative to a perpendicular to the associated surface (from which the connecting section is accessible) is between 5° and 40°, preferably between 10° and 20° and in particular about 15°.

If suspension ropes are then used with a length that, with the given distance between the lifting anchors, leads to an angle between the suspension rope and a perpendicular to the concrete surface of about 30°, the axis of the anchor section of the lifting anchor bisects this angle and the difference between the pulling direction of the suspension rope and of the axis of the anchor section is then only 15° instead of 30°, so that the corresponding lateral force is significantly reduced.

The recess former is called as such because after the casting of a precast concrete part and before and possibly also after the removal of the formwork, it lies flush in a concrete surface from which it still has to be removed, so that afterwards a recess remains in the concrete surface, the volume of which previously occupied by the recess former and at the bottom of which the connecting portion of the transport anchor is accessible.

In a variant of the invention, the recess body is designed as a nail plate, which has two opposite surfaces, which are not parallel to one another, but are preferably inclined relative to one another at an angle of 15°±5°.

The surface of the recess body facing the connecting section has a receiving element that fits the connecting section, namely a threaded socket. Depending on whether the threaded section of the transport anchor has an internal thread or an external thread, the threaded socket on the recess body is either a threaded bolt with an external thread or a threaded sleeve with an internal thread.

In the invention, the recess former has two opposite planar surfaces which are inclined towards each other and connected to each other by a peripheral edge surface.

The peripheral edge surface forms part of a rotationally symmetrical surface, because this means that the recess former can be rotated in the recess formed in the concrete and can therefore be more easily removed from this recess. The rotationally symmetrical surface is expediently a spherical surface or a conical surface, but the edge surface on the recess body is generally no longer rotationally symmetrical since it can have a varying width along its circumference.

The recess body has a threaded socket, which extends along the axis of the rotationally symmetrical surface defined by the edge surface, so that it can be easily unscrewed from a threaded section on the transport anchor by rotating the entire recess body. Since the recess in the concrete also reproduces the edge surface of the recess former and the thread axis of the threaded section and the threaded socket on the recess former is at the same time the axis of symmetry of the associated surface of revolution, the recess former can be rotated in the concrete recess and the recess former can thus be detached from the threaded section.

To this end, it is also expedient if the recess body also has an actuating element for releasing the threaded section of the transport anchor. For example, the upper surface of a nail plate could have a recess in the form of a hexagon socket, which makes it possible to rotate the recess body using a tool (Allen key) inserted into the hexagon socket and thus detach it from the threaded section.

Furthermore, it is expedient if the recess body has a marking which indicates the level of a maximum angle between the upper surface and the lower surface of the nailing plate. In this way, it is easier to position the recess former on a formwork in the desired direction, ie with maximum inclination in the direction of an adjacent transport anchor.

Finally, the present invention also relates to a method for producing a corresponding concrete part according to claim 6, in which the threaded section of a concrete part is fastened in a sealed manner to a surface of a recess body such that after a sealed direct or indirect connection of the recess body to the associated formwork wall, the axis of the Threaded section runs inclined relative to a perpendicular to the formwork wall. The transport anchor is positioned using the means or recess bodies described above. the formwork wall referred to here is always the part of the formwork on which the recess former lies tightly

The method for producing a precast concrete part with at least one cast-in transport anchor, which has an anchor section and an adjoining connecting section, is characterized in particular in that a combination according to one of Claims 1 to 5 is used to fix the transport anchor in a formwork for the precast concrete part in to position an alignment relative to a surface of the precast concrete part such that the axis of the transport anchor runs inclined relative to a perpendicular to the surface of the precast concrete part.

In a further embodiment of the method it is provided that at least two lifting anchors are positioned in the formwork in such a way that the axes of the threaded sections of two lifting anchors are inclined towards one another.

A precast concrete part with at least one surface on which transport anchors concreted into the precast concrete part are accessible is characterized in that the relevant surface of the precast concrete part has at least one recess which has a base surface inclined at an angle to the surface, from which a connecting section of a transport anchor is accessible, wherein the longitudinal axis of the transport anchor or the anchor part thereof extends perpendicularly to the base of the recess.

The base of a recess in this surface, which is inclined relative to a surface of a precast concrete part and from which a lifting anchor extends perpendicularly to the base into the concrete, is a characteristic for the use of the positioning device according to the invention and the products produced with it. The inclination of the base of the recess relative to the respective surface is in principle arbitrarily selectable and can be between, for example between 5° and 50° can be selected at will, but an angle between 10° and 20°, in particular 15°, has proven to be very useful for most applications.

In particular, according to one embodiment, it is provided that at least one surface of the precast concrete part has at least two recesses, the base areas of which are inclined in opposite directions and towards one another.

Furthermore, according to one embodiment, the threaded section is a threaded sleeve whose free end face is flush with the bottom of the recess.

Figur 1

schematisch eine Seitenansicht eines Betonfertigteils mit darin unter einem Neigungswinkel angeordneten Transportankern,

Figur 2

eine Transportsituation mit einem Tragseil an einem Kranhaken,

Figur 3

eine Transportsituation mit Aufhängung an einem Tragbalken,

Figur 4

einen Nagelteller gemäß einer Ausführungsform der Erfindung in einer Ansicht von unten,

Figur 5

eine Schnittansicht des Nageltellers aus Figur 4 gemäß der Schnittlinie V-V,

Figur 6

eine Ansicht auf den Nagelteller nach Figur 4 von oben,

Figur 7

eine weitere schematische Ansicht eines Abschnitts eines Betonfertigteils mit zwei verschiedenen Aussparungskörpern,

Figur 8

eine perspektivische Ansicht der Ausführungsform gemäß Figur 7, und

Figur 9

einen mit dem Gewindestutzen eines Nageltellers verschraubten Transportanker.

Further advantages, features and application possibilities of the present invention become clear on the basis of the following description of a preferred embodiment and the associated figures. Show it:

figure 1

a schematic side view of a precast concrete part with lifting anchors arranged therein at an angle of inclination,

figure 2

a transport situation with a carrying rope on a crane hook,

figure 3

a transport situation with suspension on a supporting beam,

figure 4

a nail plate according to an embodiment of the invention in a view from below,

figure 5

a sectional view of the nail plate figure 4 according to the section line VV,

figure 6

a view of the nail plate figure 4 from above,

figure 7

a further schematic view of a section of a precast concrete part with two different recess formers,

figure 8

a perspective view of the embodiment according to FIG figure 7 , and

figure 9

a transport anchor screwed to the threaded socket of a nailing plate.

According to figure 1 one can see a precast concrete part 30, which is designed, for example, in the form of a plate-shaped wall element, which has a (in figure 1 not directly visible) peripheral edge surface 32 has. The positions of two lifting anchors 20 , which consist of an anchor section 22 and a threaded sleeve 21 ′ attached to one end of the anchor section 22 , can also be seen in the precast concrete part 30 , indicated by dashed lines. The anchor sections 22 are elongated parts such as wire ropes, wire rope loops or sections of reinforcing bars, which are firmly connected (e.g. pressed and/or welded) at one end to a threaded sleeve 21' and essentially extend along an imaginary extension of the Thread or the thread axis 50 extend (see figure 9 ). The transport anchors 20 thus define a longitudinal direction, namely that of the thread axis 50, which is also the longitudinal axis of the anchor part.

The angle of inclination of the lifting anchor 1, whose longitudinal direction is defined by the extent of the axis 50 of the threaded section 21', is 15° in relation to a perpendicular to the edge surface 32 in the figures. in the in figure 2 In the carrying situation shown with a rope 40, both ends of which are directly or indirectly connected to the threaded sleeves 21', the carrying ropes run at an angle of 30° relative to a vertical on the edge surface 32. The direction of pull of the carrying ropes is therefore opposite to the longitudinal direction of the lifting anchor 20 only inclined by 15°.

The pulling direction (60° to the edge surface 32) can be determined in advance by selecting a specific cable length and specifying a specific distance between the lifting anchors and the edge surface 32.

figure 3 FIG. 12 shows another possible transport situation, in which a carrying beam 41 is used, so that the corresponding carrying cables 40 extend perpendicularly to the upper edge surface 32 of the precast concrete part 30. FIG.

Here, too, the carrying cables 40 run at an angle of only 15° relative to the axial direction of the threaded section, so that only very small transverse forces occur in this carrying situation.

the Figures 4 to 6 show a nailing plate 11 designed for the corresponding inclination of the lifting anchor. figure 4 shows the lower surface 4 with the threaded socket 3 and an edge surface 6 forming part of a conical surface in a plan view from below. The axis of the conical surface 6 coincides with the axis 50 of the threaded socket 3 . The lower surface 4 and the edge surface 6 can also be seen in figure 5 , as well as the upper surface 5, the nail holes 9, via which the nail plate is attached to a formwork and the actuating element 7, which in this case is designed as a hexagon socket. In the plan view from above according to figure 6 you can also see a marking 8 on the surface 5, here in the form of an arrow, which shows in which direction and in which plane the axis of the threaded section attached to the nailing plate runs inclined at a maximum angle relative to the upper surface 5, which in the cutting plane according to figure 5 recognizable angle of 15° between sides 4 and 5.

figure 7 shows a variant of the present invention that works with two recess formers 11, 12, with the recess former 11' being a hemispherical shell, in the center of which the spherical head section of a transport anchor 20 is accommodated essentially symmetrically, with the surface of a shuttering board having the edge surface 32 limited, a wedge 12 rests with a surface 17, while the opposite wedge surface 16, which in turn is inclined by about 15° relative to the wedge surface 17, forms a contact surface for the recess body 11'. It is also possible in this way for the transport anchor 20 to run inclined at an angle of, in this case, 15° relative to a perpendicular to the edge surface.

the figure 8 shows the arrangement according to figure 7 again in a perspective view, with the wedge 17 forming a recess 31 which has a base area inclined relative to the edge surface 32, with the recess body 11' being arranged in the bottom of the recess 31, which is tightly connected to the ball head section 21" and this Protects the head section 21" of the transport anchor 20 from the ingress of concrete or concrete milk in the area of the ball head.

After their completion, all concrete parts shown here have one or more recesses 31 on at least one of their edge surfaces 30, the base area of which, which is defined by the fact that it offers access to a connecting section of a transport anchor, is inclined relative to the edge surface 32, with the longitudinal axis 50 of the transport anchor runs perpendicular to the base of the recess.

figure 9 finally shows a transport anchor 20 with a threaded portion 21' and the anchor portion 22, which extends along the axis 50 of the anchor portion, which is at the same time the axis of the threaded portion 21', the anchor portion being made of a wire rope, for example or a wire rope loop, or parallel ropes pressed into a sleeve at the lower end, or a round bar with a swaged base at the end, or straight or corrugated reinforcing steel. The threaded section 21' is screwed onto a threaded socket 3 of a recess body 11, specifically in the form of a nailing plate 11, the threaded socket 3 of the nailing plate 11 extending with its axis perpendicular to the lower surface 4 of the nailing plate 11, which in turn faces the upper surface 5 of the nailing plate 11 is inclined by approx. 15°. Thus, the axis 50 of the threaded portion 21 'of the lifting anchor 20 is inclined relative to a perpendicular to the surface 5, which in turn is flush in a plane with the corresponding edge surface 32 of a precast concrete part.

Claims (7)

1. Combination of a transport anchor (20) and a device for positioning the transport anchor (20) in a formwork for a precast concrete part (30), wherein the transport anchor (20) has an elongate anchor portion (22), which defines a longitudinal axis (50), and a connection portion (21') adjoining one end of the anchor portion (22) in the direction of the longitudinal axis, wherein the connection portion (21) is a threaded portion (21'), the axis of which coincides with the longitudinal axis (50) of the anchor portion (22), wherein the device has a recess unit (1, 11), which can be connected on one side (4) to the connection portion (21') in a sealed manner and on a side (5, 25) facing away from the connection portion (21') can be connected directly to the inner wall of a formwork in a sealing manner, wherein the recess unit has two flat surfaces (4, 5) lying opposite one another, wherein the two surfaces (4, 5) are inclined relative to one another and connected to one another by a circumferential edge surface (6), wherein the circumferential edge surface (6) forms a part of a rotationally symmetrical surface, wherein the surface of the recess unit (1, 11) facing the threaded portion has a threaded connector (3) fitting the threaded portion (21'), wherein the threaded connector (3) is formed as a threaded bolt with an external thread or a threaded sleeve with an internal thread, wherein the threaded connector extends from the recess unit (1, 11) perpendicular to the surface (4) facing the threaded portion (21') and along an axis (50') of the rotationally symmetrical surface formed by the edge surface (6), with the result that in the case of a recess unit (1) aligned in an installation position the longitudinal axis (50) of the anchor portion (22) runs inclined at an angle of less than 90° to the surface (5, 15, 25) of the recess unit (1, 11, 12) to be connected in a sealing manner to a formwork wall, wherein the threaded connector (3) has a thread axis, wherein the rotationally symmetrical surface has an axis of symmetry and wherein the thread axis is identical to the axis of symmetry.
2. Combination according to claim 1, characterized in that the angle is between 50° and 85°, preferably between 70° and 80° and in particular approximately 75°.
3. Combination according to one of the preceding claims, characterized in that the recess unit (1) is formed as a nailing plate (1), which has two surfaces (4, 5) lying opposite one another which are inclined at an angle of 15° +/- 5° relative to one another.
4. Combination according to one of the preceding claims, characterized in that the rotationally symmetrical surface (6) is a spherical or conical surface (6).
5. Combination according to one of the preceding claims, characterized in that the recess unit (1) has a marking (8), which indicates the direction of a maximum angle between the upper surface (5) and the lower surface (4) of the nailing plate (1), and/or the recess unit has an actuating element (7) for releasing the connection portion of the transport anchor.
6. Method for producing a precast concrete part with at least one cast-in transport anchor (20), which has a connection portion and, adjoining that, an anchor portion (22), characterized in that a combination according to one of claims 1 to 5 is used in order to position the transport anchor (20) in a formwork for the precast concrete part in an alignment relative to a surface of the precast concrete part such that the axis of the anchor portion of the transport anchor runs inclined relative to a perpendicular to the surface of the precast concrete part.
7. Method according to claim 6, characterized in that at least two transport anchors are positioned in the formwork such that the axes of the anchor portions of in each case two transport anchors are inclined towards one another.

Images