Load transfer arrangement for a wooden component

Abstract

Load transfer arrangement (1) for a wood or wood-based material component (2), comprising a lifting fitting (6) embedded in a wood component (2) to be lifted, wherein the lifting fitting (6) is cylindrically plate-shaped with a first diameter (d), a thickness (t) and a cylindrical outer surface (f) with a cylinder axis (Z) and is embedded in a cylindrical recess (4) in the wood component (2), which has a second diameter (D) corresponding to the first diameter (d), a depth (T) at least corresponding to the thickness (t) and a cylindrical inner surface (F), wherein the lifting fitting (6) has a number of screw holes (8) extending in the thickness direction, through each of which a fastening screw (10) screwed into the wood component (2) extends, wherein the fastening screws (10) are arranged parallel to each other and in the direction of the cylinder axis (Z) of the lifting fitting (6),wherein the lifting fitting (6) has a fastening means (12) for connection to a lifting device, through which a vertical force (HV) acting in the direction of the cylinder axis (Z) of the lifting fitting (6) and a horizontal force (HH) acting transversely thereto can be introduced into the lifting fitting (6), wherein the vertical force (HV) can be introduced into the wooden component (2) through the fastening screws (10) and the horizontal force (HH) can be introduced completely or to a large extent from the outer surface (f) of the lifting fitting (6) via the inner surface (F) of the recess (4) into the wooden component (2).

Description

[0001] The invention relates to a load transmission arrangement for a wooden or wood-based component, comprising a lifting fitting embedded in a wooden component to be lifted, which is cylindrically plate-shaped with a first diameter, a thickness, and a cylindrical outer surface with a cylinder axis, and is embedded in a cylindrical recess in the wooden component, which has a second diameter corresponding to the first diameter, a depth corresponding at least to the thickness of the lifting fitting, and a cylindrical inner surface. The lifting fitting is provided with a number of screw holes extending in the thickness direction, through each of which a fastening screw screwed into the wooden component extends. The fastening screws are arranged parallel to one another and in the direction of the cylinder axis of the lifting fitting. The lifting fitting has a fastening means for connection to a lifting device.through which a vertical force acting in the direction of the cylinder axis of the lifting fitting and a horizontal force acting transversely thereto can be introduced into the lifting fitting, whereby the vertical force can be introduced into the wooden component through the fastening screws and the horizontal force can be introduced completely or for the most part from the outer surface of the lifting fitting via the inner surface of the recess into the wooden component.

[0002] The object of the invention is to create a load transfer assembly capable of absorbing large forces while minimizing shear stress on the fastening screws. The invention is particularly suitable for lifting heavy wooden components, but also for connecting loads that do not result from a lifting operation, for example, in components assembled using the load transfer assembly.

[0003] Due to the arrangement of the fastening screws in the direction of the cylinder axis of the lifting fitting and the precisely fitting recess and thus in the direction of the vertical force to be absorbed on the one hand and due to the perpendicular alignment of the outer surface of the lifting fitting and the inner surface of the recess in the wooden component and thus in the direction of the horizontal force to be absorbed on the other hand, in the event of a load the horizontal force is absorbed completely or almost exclusively by the surface pressure between parts of the outer surface of the lifting fitting and the inner surface of the recess, while the vertical force is absorbed exclusively by the fastening screws.This allows the fastening screws, as well as the size and diameter of the outer and inner surfaces, to be optimally adapted to the expected load components, ensuring that additional shear stress on the fastening screws is completely or almost completely avoided. A slight eccentricity of the vertical force with respect to the fastening screws is compensated by a correspondingly uneven tensile stress on the fastening screws.

[0004] It is possible that the cylindrical shape of the lifting fitting and the recess, seen in the direction of the cylinder axis, is not circular, but polygonal or polygonal with rounded corners.

[0005] The load transfer arrangement according to the invention is used in particular for lifting heavy wooden components, in other words for absorbing horizontal and vertical forces that are greater than 1 kN, 2 kN or 5 kN.

[0006] The first diameter can be at least 50 mm, 100 mm or 150 mm.

[0007] The thickness can be at least 5 mm, 10 mm, 15 mm or 20 mm.

[0008] The fastening screws can have a length of at least 50 mm, 100 mm, 150 mm or 200 mm.

[0009] The number of fastening screws can be at least 4, 5, 6, 7, 8, 9, 10, 11 or 12.

[0010] It is advantageous for the fastening screws to be arranged at equal mutual spacing over the lifting fitting and / or in an arrangement in which the fastening screws are arranged in a pattern whose centre of gravity is approximately at the centre of the fastening means.

[0011] Preferably, the lifting fitting is completely accommodated in the recess. The depth of the recess can be at least 0.5, 1.0, 1.1, 1.2, 1.3, 1.4 or 1.5 times the thickness of the lifting fitting. Only partial accommodation of the lifting fitting in the recess is possible, in which case the lifting fitting protrudes from the recess with part of its thickness and can serve with the protruding part, for example, as a tenon for positioning and connecting to other components. The first diameter and the thickness of the lifting fitting can be so large that a surface pressure between the outer surface of the lifting fitting and the inner surface of the recess enables the transmission of a horizontal force of 2 kN or more without exceeding the standard load-bearing capacity of the wood. In addition, the required edge distances must be observed, i.e. the lateral orradial distance between the inner surface of the recess and an outer edge of the timber member or any opening in the timber member.

[0012] The fastening means can be an opening in the lifting fitting into which a lifting element can be inserted as a connecting means to a lifting device, e.g., a ball-and-socket lifting pin. The opening can be provided with an internal thread into which a lifting element provided with an eyelet can be screwed as a connecting means for inserting a lifting rope or hook, in particular a swivel lifting eyelet ("swivel hoist ring"). The wooden component can have a blind hole in the base of the recess in the area of ​​the opening so that the lifting element (connecting means) can be fully inserted.

[0013] Further advantages and features of the invention will become apparent from the following description of an embodiment, with reference to a drawing in which Fig. 1 shows a schematic plan view of a load transmission arrangement according to the invention, Fig. 2 a sectional view according to section line DD in Fig. 1 with two visible fastening screws, Fig. 3 an enlarged view according to Fig. 2 with four visible fastening screws, Fig. 4 shows a partially rectangular cutaway view of a load transmission arrangement with a lifting element or connecting means.

[0014] The load transmission arrangement 1 initially comprises a lifting force H ( Fig. 2) A wooden component 2 to be lifted, which in the example shown is glued together from a number of cuboid-shaped wooden elements 2a ("cross-laminated timber") and is provided with a cylindrical recess 4. Furthermore, the load transmission arrangement comprises a lifting fitting 6 embedded in the recess 4, which is cylindrically plate-shaped with a first diameter d, a thickness t, and a cylinder-shaped outer surface f with cylinder axis Z.

[0015] The recess 4 has a second diameter D corresponding to the first diameter d, a depth T corresponding at least to the thickness t and a cylinder jacket-shaped inner surface F, the cylinder axis of which coincides with the cylinder axis Z of the lifting fitting 6, apart from any manufacturing tolerances.

[0016] To avoid play, the lifting fitting 6 is inserted tightly into the recess 4, ie the first diameter d is practically identical to the second diameter D and, depending on the manufacturing possibilities, slightly smaller or even larger than this in order to ensure the tightest possible fit or even a press fit.

[0017] The lifting fitting 6 has a number of screw holes 8 that run in the thickness direction or in the direction of a cylinder axis Z of the cylindrical outer surface f of the lifting fitting 6. A fastening screw 10 extends through each screw hole 8, wherein the fastening screws 10 also extend parallel to the cylinder axis Z and are screwed into the wooden component 2. A flat underside 6a of the lifting fitting 6 rests firmly against a flat bottom 4a of the recess 4.

[0018] The lifting fitting 6 further comprises a fastening means for attaching a connecting element for connection to a lifting device. In the illustrated embodiment, the fastening means is formed by a central opening 12 with an internal thread 12a extending in the direction of the cylinder axis Z. A lifting element 14 provided with an eyelet is screwed into the opening 12 as a connecting means. This lifting element is a pivotable lifting eyelet ("swivel hoist ring"). The eyelet 16 of the lifting element 14 can serve for inserting a lifting rope or a hook or spreader element attached to a lifting rope.

[0019] The eyelet 16 is pivotally connected to a base body 18 of the lifting element 14 about a pivot axis s running transversely to the cylinder axis Z, so that the wooden component 2 can be lifted with the (see Fig.2) The lifting force H acting vertically upwards can assume any inclined position, depending on the center of gravity of the wooden component and, if applicable, the location of additional lifting points. A vertical force HV directed in the direction of the cylinder axis Z and, if applicable, a horizontal force HH directed perpendicular thereto are transmitted from the lifting element 14 to the lifting fitting 6, with the vertical force HV being introduced into the wooden component 2 by the fastening screws 10, and the horizontal force HH being introduced entirely or largely from the outer surface f of the lifting fitting 6 via the inner surface F of the recess 4 into the wooden component 2.

[0020] This has the advantage that the fastening screws 10 are exposed to no or almost no shear stress, since the horizontal force is transferred exclusively or for the most part into the wooden component via the outer surface of the lifting fitting and the inner surface of the recess (“hole bearing”). List of reference symbols 1 load transfer arrangement 2 wooden component 2a wooden element 4 recess 4a Floor 6 Lifting fitting 6a bottom 8 screw holes 10 fixing screws 12 Opening (fastening means) 12a internal thread 14 Lifting element (connecting device, e.g. lifting swivel) 16 eyelets 18 basic bodies d first diameter t thickness f outer surface D second diameter T Depth F inner surface Z cylinder axis s swivel axis H lifting capacity HV vertical force HH horizontal force

Claims

[1] Load transmission arrangement (1) for a wooden or wood-based component (2), comprising a lifting fitting (6) embedded in a wooden component (2) to be lifted, wherein the lifting fitting (6) is cylindrically plate-shaped with a first diameter (d), a thickness (t), and a cylindrical outer surface (f) with a cylinder axis (Z), and is embedded in a cylindrical recess (4) in the wooden component (2), which recess has a second diameter (D) corresponding to the first diameter (d), a depth (T) corresponding at least to the thickness (t), and a cylindrical inner surface (F), wherein the lifting fitting (6) has a number of screw holes (8) extending in the thickness direction, through each of which a fastening screw (10) screwed into the wooden component (2) extends, wherein the fastening screws (10) are arranged parallel to one another and in the direction of the cylinder axis (Z) of the lifting fitting (6),wherein the lifting fitting (6) has a fastening means (12) for connection to a lifting device, by means of which a vertical force (HV) acting in the direction of the cylinder axis (Z) of the lifting fitting (6) and a horizontal force (HH) acting transversely thereto can be introduced into the lifting fitting (6), wherein the vertical force (HV) can be introduced into the wooden component (2) by the fastening screws (10) and the horizontal force (HH) can be introduced completely or for the most part from the outer surface (f) of the lifting fitting (6) via the inner surface (F) of the recess (4) into the wooden component (2). [2] Load transfer arrangement according to claim 1, characterized by that the horizontal force (HH) and / or the vertical force (HV) is greater than 1 kN, 2 kN or 5 kN. [3] Load transfer arrangement according to claim 1 or 2, characterized by that the lifting fitting (6) is partially or completely accommodated in the recess (4). [4] Load transfer arrangement according to one of the preceding claims, characterized by that the depth (T) of the recess (4) is at least 0.5 times, 1 times, 1.1 times, 1.2 times, 1.3 times, 1.4 times or 1.5 times the thickness (t) of the lifting fitting (6). [5] Load transfer arrangement according to one of the preceding claims, characterized by that the first diameter (d) and the thickness (t) of the lifting fitting (6) are so large that the surface pressure between the outer surface (f) of the lifting fitting (6) and the inner surface (F) of the recess (4) does not exceed the standard-compliant maximum load-bearing capacity of the timber component at a horizontal force of more than 2 kN and the required edge distances are observed. [6] Load transfer arrangement according to one of the preceding claims, characterized by that the first diameter (d) is at least 50 mm, 100 mm or 150 mm. [7] Load transfer arrangement according to one of the preceding claims, characterized by that the thickness (t) is at least 5 mm, 10 mm, 15 mm or 20 mm. [8] Load transfer arrangement according to one of the preceding claims, characterized by that the fastening screws (10) have a length of at least 50 mm, 100 mm, 150 mm or 200 mm. [9] Load transfer arrangement according to one of the preceding claims, characterized by that the number of fastening screws (10) is at least 4, 5, 6, 7, 8, 9, 10, 11 or 12. [10] Load transfer arrangement according to one of the preceding claims, characterized by that the fastening screws are arranged at the same distance from one another or distributed over the lifting fitting (6). [11] Load transfer arrangement according to one of the preceding claims, characterized bythat the fastening means (12) is an opening in the lifting fitting (6) for receiving a lifting element (14) as a connecting means with the lifting device, which can be provided with an internal thread (12a) into which a lifting element (14) provided with an eyelet (16) can be screwed, in particular a pivotable lifting eyelet (“ball head anchor”, “swivel hoist ring”). [12] Load transfer arrangement according to one of the preceding claims, characterized by that the cylindrical shape of the lifting fitting (6) and the recess (4) viewed in the direction of the cylinder axis (Z) is not circular, but polygonal or polygonal with rounded corners. [13] Load transfer arrangement according to claim 11 or 12, characterized by that the wooden component (2) has a blind hole in a base (4a) of the recess (4) in the region of the opening (12) so that the lifting element (14) or connecting means can be fully inserted. [14] Load transfer arrangement according to one of the preceding claims, characterized by that a connecting means is held on the fastening means (12), which is a bolt or other suitable connecting means customary in building construction, which serves to connect static loads in a building, i.e. not only for lifting or transporting a wooden component.

Images