EP2185463A1

EP2185463A1 - Profile shape for a crane jib

Info

Publication number: EP2185463A1
Application number: EP08782838A
Authority: EP
Inventors: Eckhard Wimmer
Original assignee: Palfinger AG
Current assignee: Palfinger AG
Priority date: 2007-09-05
Filing date: 2008-08-29
Publication date: 2010-05-19
Also published as: CN101827776A; WO2009029968A1; BRPI0816409A2; CA2697304A1; MX2010002601A; RU2010112842A

Abstract

The invention relates to a crane jib for a crane, having a longitudinal axis and an imaginary contour line that extends in a transversal plane relative to an axis of symmetry (s) in an at least approximately mirror-symmetric manner, the contour line intersecting the axis of symmetry (s) in a first and a second point of intersection (S1, S2) and the contour line having an extremal point (E) with a maximum distance (e) from the axis of symmetry (s) between the first point of intersection (S1) and a center (M) that is equally interspaced from the first and the second point of intersection (S1, S2). The distance (d) of the contour line from the axis of symmetry (s) is smaller or equal 0.8 times the maximum distance (e) at approximately a fourth of the distance (D) between the first and the second point of intersection (S1, S2), starting from the second point of intersection (S2).

Description

Profile shape for a crane arm

The present invention relates to a crane arm for a crane, having a longitudinal axis and an imaginary contour line extending at least approximately mirror-symmetrically in a transverse plane with respect to an axis of symmetry, wherein the contour line intersects the symmetry axis in a first and a second intersection, and wherein the contour line between the first intersection and an equidistant from the first and the second intersection point center has a maximum point with maximum distance from the axis of symmetry.

Such a crane is shown, for example, in FIG. 13 of EP 583 552 B1.

This crane arm has the disadvantage that, in particular when installed in a boom system in the upper region of the crane arm an unfavorable force is applied. Furthermore, the production of such a crane arm is relatively expensive.

The object of the invention is to solve the discussed problems of the prior art.

This object is achieved by a crane arm with the features of claim 1.

Of course, due to the material thickness of the components forming it, a real crane arm has both an outer contour and an inner contour. The "imaginary contour line" refers to the outer contour of the crane arm.

For the purposes of this disclosure, centroid is understood to be the center of gravity of the entire area enclosed by the imaginary contour line (FIG. 1h). The term "area centroid" is therefore not to be understood in relation to the enclosed between the outer and inner contour surface.

By tapering the contour line upwards results in a favorable

Ratio of leg length to sheet thickness. By the invention, the use of thinner sheets is possible, as was the case in the prior art. The measures according to the invention cause further that the upper part of the crane arm as a whole for the introduction of force, in particular between the boom extensions when installed in a boom system, can be used.

Further advantageous embodiments are defined in the dependent claims.

The invention further relates to a boom system for a crane, wherein at least one boom and / or a boom extension are designed as a crane arm according to one of claims 1 to 20. Preferably, between one and twenty, preferably between five or ten boom extensions are provided. It is particularly preferred that more than five boom extensions are provided.

The invention further relates to a crane, in particular loading crane, with a crane arm according to one of the aforementioned embodiments or a boom system of the aforementioned type and a commercial vehicle equipped with such a crane.

Further advantages and details of the invention will become apparent from the figures and the associated description of the figures. Showing:

1a shows a first embodiment of the imaginary contour line of a crane arm according to the invention,

1b and 1c, the construction of a contour line (Fig. 1b) and the corresponding sheet metal construction (Fig. 1c) of an embodiment in which the circular arc-shaped portion ki is approximated by a polygon,

1d shows a boom system with three boom extensions according to FIG.

1b, Fig. 1e, the crane arm of FIGS. 1a to 1c, wherein the position of

Fig. 1f is a boom system with a boom extension, wherein the

Arrangement of bearing elements is shown

1g shows a boom system with a boom extension, wherein the arcuate section in the boom and the boom extension has been approximated by different polygons, 1h shows the crane arm according to FIGS. 1a to 1c and 1e, wherein the area to which the centroid of the area relates has been drawn by dash-dotted lines as a representative of all exemplary embodiments, FIG. 2 shows a second exemplary embodiment of the imaginary contour line of a crane arm according to the invention,

3 shows a third embodiment of the contour line of a crane arm according to the invention,

Fig. 4 is a perspective view of a boom system according to Fig. 1d and

Fig. 5 is a commercial vehicle with a crane according to the invention.

It should be understood that all the figures are true to scale insofar as the lengths of the individual contour sections and the angles represented are shown in the correct relationship to one another. All angles refer to the degree, so that a full angle corresponds to 360 degrees. An acute angle is understood to mean an angle smaller than Va. Full angle. An obtuse angle is understood to mean an angle greater than% and less than V * full angle. An angle equal to% full angle is called the right angle.

Fig. 1a shows a first embodiment of the course of the imaginary contour line of the crane arm in a transverse plane of the crane arm. Transverse plane is understood to mean a plane which is pierced orthogonally by the longitudinal axis of the crane arm. All crane arms according to the invention have an axis of symmetry s arranged in the transversal plane, with respect to which the contour line of the crane arm in the transverse plane runs at least approximately mirror-symmetrically. In the event that the crane arm has the same cross-sectional shape over most or all of its longitudinal extent, this symmetry axis s represents the intersecting line of the transverse plane with the plane of symmetry (median plane) along the longitudinal axis. In all embodiments, the contour line intersects the symmetry axis s in a first one and a second intersection Si, S ₂ . The center point M arranged equidistant to the first and the second intersection point Si, S ₂ on the symmetry axis s represents the position of the half height of the crane arm in the transversal plane. Starting from midpoint M in the direction of the intersection point S ₂ , one finds himself in a region of Crane arm, which is loaded in operation mainly to train. The area of the crane arm lying between the midpoint M and the first intersection point S ₁ is subjected to essentially pressure during operation.

The course of the contour line of the crane arm shown in FIG. 1 has four sections ki, gi, g ₂ , g ₃ that can be distinguished from one another.

The section ki arranged in the region of the greatest pressure loading in operation has a circular arc shape since this cross-sectional shape, as known per se, has reduced compressive stresses and a reduction in the risk of buckling. It is sufficient if this section in the sense at least approximately circular arc-shaped, as it can be approximated by a polygon, as shown in Figures 1 b and 1c. The approximation of the arcuate section ^ by a polygonal line allows for easier production by folding the sheet metal forming the crane arm. Of course, however, a circular arc-shaped formation can be realized by means of a rolling process.

The circular arc-shaped section k: can also be approximately circular arc-shaped in the sense that it can be formed, for example, by one or more elliptical sections with a correspondingly low eccentricity. It would also be conceivable to form a circular-arc-shaped sections k 1 by a series of correspondingly short, straight-line, elliptical and / or circular-arc-shaped segments.

As shown in Fig. 1, it is particularly advantageous if the circular arc-shaped portion ki is formed as a quarter circle arc, that is, extends over an angle of approximately 90 degrees. This makes it possible to form the majority of the course of the contour line between the first intersection point Si and the center point M in the form of an arcuate section k-. Particularly preferred is the variant shown in Fig. 1, in which the center of curvature K of the circular arc portion ki is in the vicinity or on the axis of symmetry s and the center of curvature K of the circular arc portion ki between the first intersection Si and the center M is located. Unlike shown in Fig. 1, the circular arc-shaped portion k _t may well up to the first intersection S. ₁ extend. In this case, therefore, the entire contour line in the region of the intersection S ₁ and the center M is formed as a circular arc-shaped portion ki.

However, the embodiment shown in FIG. 1 is particularly preferred in which tangential to the circular arc-shaped section k, in the direction of the first

Intersection Si connects a third rectilinear section g ₃ , with the

Symmetry axis s an angle γ less than 90 degrees includes (here is the

Angle γ about 72 degrees). This results in a good weldability of the

Crane arm, a better clamping ability for welding through the obliquely meeting sections and the possibility of performing a longitudinal weld without additional edge preparation. Overall, there is a process-reliable

Education.

The angle is preferably less than 80 degrees. Preferably, the angle γ is greater than 70 degrees.

In the embodiment shown in FIG. 1, the center of curvature K of the circular arc-shaped portion ki is located directly on the axis of symmetry s between the center M and the first intersection point S ₁ . Unlike shown, the point of curvature K can also be arranged slightly offset from the axis of symmetry s. However, it should preferably always be located in the region between the center M and the first intersection S ₁ .

The first rectilinear section gi adjoins the arcuate section ki in the direction of the second point of intersection S ₂ tangentially to the auxiliary circle illustrated in FIGS. 1 a and 1b, which extends over the major part of the contour path between the midpoint M and the second intersection point S. ₂ extends. By this long-drawn rectilinear training in the upper region of the crane arm and the resulting cross-sectional tapering a zone is formed, which is better than in the prior art for absorbing the tensile forces occurring here and the bearing forces in the arrangement in a boom system is suitable. The imaginary extension of g / gi of the straight portion (see Fig. 1b) includes with the axis of symmetry s ß an acute angle, which is approximately 18 degrees in the ^'embodiment shown. In general, the acute angle ß also in a range greater than 10 degrees, preferably greater than 15 degrees. In each case, an upper limit of 25 degrees is preferred, in order to rule out a flat course of the straight-line section Q ₁ .

In the exemplary embodiment according to FIG. 1, a second rectilinear section g ₂ adjoins the first rectilinear section gi, which runs up to the symmetry axis s and intersects it in the second intersection S ₂ . As can be seen in particular in Fig. 1c, it may be desirable for manufacturing reasons, if the second rectilinear portion g ₂ (unlike in Fig. 1a shown) not directly, but over a preferably curved formed further portion with the first rectilinear Section Q _{1 is} connected.

In the embodiment shown in FIG. 1, the second rectilinear section g ₂ with the axis of symmetry s an angle α, which is smaller than 90 degrees (in the embodiment of Fig. 1, the angle α is about 65 degrees). Particularly preferred is a range for the angle α less than 70 degrees. The angle α should, however, be greater than 60 degrees in this embodiment.

In a further embodiment according to FIG. 2, the second rectilinear section encloses a right angle with the axis of symmetry s.

The second rectilinear section g ₂ has the advantage that in this way in the area around the tip of the crane arm around a favorable local force introduction, as is done for example in the support of Gieitpaketen between each boom extensions is possible. The short leg length results in a favorable ratio between the sheet thickness and the leg length, so that a deformation of the crane arm in the upper area is prevented.

However, in principle, it would also be possible to form the contour profile in this area in the form of a second circular arc-shaped section k ₂ (see FIG. 3). However, this represents only a special variant of a more general idea, namely that the contour line ends in a rounding at the line of symmetry s. Alternatively to the illustrated embodiment of the rounding as a circular arc-shaped section k ₂ , the rounding could, for example, also be designed as an edging 7. In the embodiment according to FIG. 2, the imaginary contour line does not have a circular arc-shaped section K ₁ , but only rectilinear sections g ₁ , g ₂ , g ₃ , g ₄ .

More generally, for all embodiments of the crane according to the invention, it must be said that the centroid F, the area enclosed by the contour line in the transverse plane lies in a region between the center M and the first intersection S ₁ , ie below half the height of the crane arm. As a result, the cross-sectional concentration of the crane arm is displaced as possible in the pressure zone down, resulting in a lower compressive stress component.

As can be seen from the figures, the contour line of all exemplary embodiments between the first intersection point S ₁ and the second intersection point S _{2 has} an extreme point E with a maximum distance e from the axis of symmetry s. The distance D between the first intersection and the second intersection Si, S ₂ can be at least twice as large as the distance e. Preferably, the distance D is at least two and a half times as large, more preferably at least 2.75 times as large as the distance e. The distance D may each be less than three times the distance e.

It is inventively provided that the distance d of the contour line from the symmetry axis s at approximately (preferably exactly) a quarter of the distance D between the first and the second intersection S ₁ , S ₂ starting from the second intersection S _{2 is} less than or equal to 0.8 times the maximum distance e (preferably less than or equal to 0.7 times the maximum distance e). In this position it can be provided that the distance d is greater than 0.6 times the maximum distance e.

In the embodiment shown in Fig. 1, the extreme point E between the center M and the first intersection S _{1 is} approximately at the height of the center of curvature K. In the course shown in Fig. 1a, the contour line has only a single extreme point E, the means both in the direction of the first point of intersection S ₁ and in the direction of the second point of intersection S ₂ decreases starting from the extreme point E, the width of the crane arm. At the approach Of course, all points of the polygon section through which the circular arc-shaped section ki is approximated in the region of the extreme point E have this maximum distance e.

Starting from the auxiliary circle with the radius r illustrated in FIG. 1a, the exemplary embodiment according to FIG. 1 has a profile width b according to b.about.2r, a profile height D according to D3r and a profile width bi above according to bi.sub.r. These particularly advantageous dimensions can be provided quite generally in crane arms according to the invention.

1e shows for the embodiment of FIG. 1, the position of the centroid F between the center M and the first intersection point S ₁ on the axis of symmetry s. The centroid F refers to the area shown in phantom in FIG. 1h, ie to the entire area which is enclosed by the imaginary contour line (corresponding to the outer contour).

In Fig. 1f, a boom system 5 is shown with a boom extension, in addition, the storage of the boom system 5 via a bearing element 1 and the bearing of the boom extension in the boom via bearing elements 2 is shown. Of course, the embodiment shown is purely exemplary in relation to the number of boom extensions shown. The same bearing elements can be used with boom systems 5 with any number of boom extensions.

In the embodiment according to FIG. 1g, two crane arms are shown, which are, for example, a boom extension arranged in a boom. Of importance is that the circular arc-shaped section ki is approximated by different polygons. The internal cross-sectional profile has fewer bends in the region of the circular-arc-shaped portion, which may be advantageous in particular for small profiles due to production.

The production of a crane arm according to the invention can be carried out, for example, such that the crane arm is formed from two shells, which are formed in mirror image to each other and wherein one of the shells in each case corresponds to one of the embodiments. The two shells can be in the area of the first Embodiments corresponds. The two shells can be connected, for example welded, in the region of the first point of intersection S ₁ and of the second point of intersection S ₂ .

However, it is particularly preferably provided to produce the crane arm at least along a portion of its longitudinal extension of a single sheet, which is suitably shaped and then closed along a single line (for example, welded). This line can run, for example, in the area of the first intersection point Si or of the second intersection point S ₂ .

The shaping of the sheets can be done in a known manner or by folding and / or rolling and, for example, welding.

If different wall thicknesses are required, the outer contour should preferably remain the same and the sheet thickness should be applied inwards.

FIG. 4 shows by way of example a boom system 5 with a boom extension arranged in a boom.

FIG. 5 shows by way of example a commercial vehicle 3 on which a crane 4 according to the invention is arranged. The crane 4 has a boom system 5 according to the invention, it being possible for the individual boom extensions to be moved telescopically relative to one another via thrust cylinders 6. Of course, the telescopic movability can also be ensured by other drive means. In the rear region of the commercial vehicle 3, for example, an unrepresented charging structure could be arranged.

Claims

claims:

Crane crane for a crane, with a longitudinal axis and a transversely in relation to an axis of symmetry at least approximately mirror-symmetrical and at least partially rectilinear imaginary contour line, wherein the contour line intersects the axis of symmetry in a first and a second intersection, and wherein the contour line between the first intersection and a center equidistant from the first and second intersections

Having extremal point with maximum distance from the axis of symmetry, characterized in that the distance (d) of the contour line from the symmetry axis (s) at about a quarter of the distance (D) between the first and the second intersection point (S ₁ , S ₂ ) starting from the second intersection (S ₂ ) is less than or equal to 0.8 times the maximum distance (e).

2. Crane arm according to claim 1, characterized in that the centroid (F) of the enclosed by the contour line in the transverse plane surface between the first intersection (Si) and the center (M).

3. crane arm according to claim 1 or 2, characterized in that the contour line has a rectilinear portion (gθ whose imaginary extension (g /) in the direction of the second point of intersection (S ₂ ) intersects the axis of symmetry (s) and with this an acute angle (β).

4. crane arm according to one of claims 1 to 3, characterized in that the contour line between the first intersection (S ₁ ) and the center (M) at least partially an at least approximately circular arc-shaped

Section (k-0).

5. crane arm according to claim 4, characterized in that the center of curvature (K) of the circular arc-shaped portion (k _t ) is on or in the vicinity of the axis of symmetry.

6. crane arm according to claim 4 or 5, characterized in that the center of curvature (K) of the circular arc-shaped portion (k-i) between the first intersection (Si) and the center (M) is located.

7. crane arm according to ^' claim 6, characterized in that the first rectilinear portion (gi) as a tangential continuation of the circular arc-shaped portion (k-0 is formed.

8. crane arm according to one of claims 1 to 7, characterized in that the

Contour line in a second section, starting with the second intersection (S ₂ ) and extending away from the axis of symmetry (s) has a second rectilinear portion (g2).

9. crane arm according to claim 8, characterized in that the second rectilinear portion (g ₂ ) forms a right angle with the axis of symmetry (s).

10. crane arm according to claim 8, characterized in that the second rectilinear portion (g ₂ ) at an angle less than 90 degrees with the

Symmetry axis (s).

Crane crane according to one of claims 8 to 10, characterized in that the second rectilinear section (g ₂ ) is connected directly to the first rectilinear section (g-0).

12. crane arm according to one of claims 8 to 10, characterized in that the second rectilinear portion (g ₂ ) via at least one - preferably curved - formed further portion with the first rectilinear portion (g-0 is connected.

13. crane arm according to one of claims 4 to 12, characterized in that tangentially to the circular arc-shaped portion (ki) in the direction of the first point of intersection (Si), a third rectilinear portion (g ₃ ) connects, with the axis of symmetry (s) a Angle (γ) less than 90 degrees.

14. crane arm according to one of claims 1 to 13, characterized in that the circular arc-shaped portion (ki) is approximated by a polygon.

15. crane arm according to one of claims 1 to 14, characterized in that the crane arm has the same cross-sectional shape at least over a major part of its longitudinal extent.

16. crane arm according to one of claims 1 to 15, characterized in that the contour line in the direction of the second intersection point (S ₂ ) at least from the last third of the distance (D) between the first and the second intersection point (S ₁ , S ₂ ) rejuvenated.

17. crane arm according to one of claims 1 to 16, characterized in that the taper of the contour line continues to the second intersection (S ₂ ) and ends in a curve at the line of symmetry (s).

18. crane arm according to one of claims 1 to 17, characterized in that the crane arm consists of at least one sheet and the plate thickness of all sections (ki, k ₂ , gi, g ₂ , g ₃ , 9, ₄ ) of the crane arm in the transverse plane at least substantially the same size.

19. Crane arm according to one of claims 1 to 18, characterized in that the crane arm consists of two shells, which are mirror images of each other and - preferably in the region of the first point of intersection (S ₁ ) and the second point of intersection (S ₂ ) - interconnected are.

20. Crane arm according to one of claims 1 to 18, characterized in that the crane arm at least along a portion of its longitudinal extent consists of a single sheet which is closed along a single line, preferably in the region of the first intersection (Si) or of the second Intersection (S ₂ ) runs.

21. jib system for a crane, characterized in that at least one boom and / or a boom extension are designed as a crane arm according to one of claims 1 to 20.

22. Jib system according to claim 21, characterized in that between one and twenty, preferably between five and ten boom extensions are provided.

23. Jib system according to claim 21, characterized in that more than five boom extensions are provided.

24. A boom system according to any one of claims 21 to 23, characterized in that the shapes of the contour line of the boom and the contour lines of all boom extensions - if necessary, except for the degree of approximation of circular arcs by polygons - are the same.

25. Crane, in particular loading crane, characterized by a crane arm according to one of claims 1 to 20 or a boom system (5) according to one of claims 21 to 24.

26. Utility vehicle (3) with a crane (4) according to claim 25.