EP2185461B1 - Profile shape for a crane jib - Google Patents

Description

The present invention relates to a crane arm having the features of the preamble of claim 1.

A crane arm with some features of the preamble of claim 1 is shown for example in FIG EP 583 552 B1 shown.

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.

A crane arm with the features of the preamble of claim 1 is from the DE 23 17 595 A1 out.

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 the center of gravity of the entire area enclosed by the imaginary contour line (FIG. Fig. 2 ) Understood. The term "centroid" should therefore not be understood in relation to the enclosed between the outer and inner contour surface.

The measures according to the invention cause the crane arm can be made of a single sheet. The upper part of the crane arm can be used as a whole for the introduction of force, in particular between the boom extensions when installed in a boom system. By rejuvenating the contour line At the top, there is a favorable ratio of Schehkellänge to sheet thickness. By the invention, the use of thinner sheets is possible, as was the case in the prior art.

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 9. Preferably, between one and twenty, preferably between five or ten boom extensions are provided. It is particularly preferred that more than five Auslegerrverlängerungen are provided.

Fig. 1 a

ein erstes Ausführungsbeispiel der gedachten Konturlinie eines enfindungsgemäßen Kranarms,

Fig. 1b und 1c

die Konstruktion einer Konturlinie (Fig. 1 b) und die entsprechende Blechkonstruktion (Fig. 1c) eines Ausführungsbeispiels, bei welchem der kreisbogenförmige Abschnitt k₁ durch einen Polygonzug angenähert ist,

Fig. 1 d

einen Auslegersystem mit drei Auslegerverlängerungen gemäß Fig. 1b,

Fig. 1 e

den Kranarm nach den Fig. 1a bis 1c, wobei die Lage des Flächenschwerpunktes eingezeichnet ist,

Fig. 1f f

ein Auslegersystem mit einer Auslegerverlängerung, wobei die Anordnung von Lagerelementen gezeigt ist,

Fig. 1g

ein Auslegersystem mit einer Auslegerverlängerung, wobei der kreisbogenförmige Abschnitt im Ausleger und der Auslegerverlängerung durch unterschiedliche Polygone angenähert wurde,

Fig. 2

den Kranarm nach den Fig. 1a bis 1c und 1e, wobei stellvertretend für alle Ausführungsbeispiele jene Fläche, auf die sich der Flächenschwerpunkt bezieht, strichpunktiert eingezeichnet wurde,

Fig. 3

ein zweites Ausführungsbeispiel der Konturlinie eines nicht beanspruchten Kranarms,

Fig. 4

die perspektivische Ansicht eines Auslegersystems gemäß Fig. 1d und

Fig. 5

ein Nutzfahrzeug mit einem erfindungsgemäßen Kran.

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.

Fig. 1 a

A first embodiment of the imaginary contour line of an inventive crane arm,

Fig. 1b and 1c

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

Fig. 1 d

a boom system with three boom extensions according to Fig. 1b .

Fig. 1 e

the crane arm after the Fig. 1a to 1c , where the position of the centroid is indicated,

Fig. 1f f

a boom system with a boom extension, the arrangement of bearing elements being shown

Fig. 1g

a boom system with a boom extension, wherein the arcuate section in the boom and the boom extension was approximated by different polygons,

Fig. 2

the crane arm after the Fig. 1a to 1c and 1e , wherein, representative of all embodiments, that surface on the the area center of gravity is referenced, has been drawn in dotted lines,

Fig. 3

A second embodiment of the contour line of an unclaimed crane arm,

Fig. 4

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

Fig. 5

a commercial vehicle with a crane according to the invention.

It should be understood that all 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 ¼ full angle. An obtuse angle is understood to mean an angle greater than ¼ and less than ½ full angle. An angle equal to ¼ 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 S ₁ , S ₂ . The center point M arranged equidistant to the first and the second intersection point S ₁ , S ₂ on the symmetry axis s represents the position of the half height of the crane arm in the transversal plane. Starting from the midpoint M in the direction of the intersection point S ₂ , one finds himself in an area of the 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 S1 is subjected essentially to pressure during operation.

The in Fig. 1 illustrated course of the contour line of the crane arm has four mutually distinguishable sections k ₁ , g ₁ , g ₂ , g ₃ .

The arranged in the region of the largest in the operating pressure load section k ₁ is arc-shaped, as this cross-sectional shape, as is known, has reduced compressive stresses and reduction of Beulgefährdung. It is sufficient if this section is in the sense at least approximately circular arc-shaped, as it can be approximated by a polygon, as in the Fig. 1b and 1c is shown. The approximation of the circular arc-shaped portion k ₁ 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 ₁ 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 section k ₁ by a series of correspondingly short, straight-line, elliptical and / or circular-arc-shaped segments.

As in Fig. 1 illustrated, it is particularly advantageous if the circular arc-shaped portion k _{1 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 S ₁ and the center M in the form of a circular arc-shaped portion k ₁ . Particularly preferred is the in Fig. 1 illustrated variant in which the center of curvature K of the circular arc-shaped portion k _{1 is} in the vicinity or on the axis of symmetry s and the center of curvature K of the circular arc-shaped portion k ₁ between the first intersection S ₁ and the center M is located. Unlike in Fig. 1 illustrated, the circular arc-shaped portion k ₁ may well extend to the first intersection point S ₁ . In this case, therefore, the entire contour line in the region of the intersection S ₁ and the point M is formed as a circular arc-shaped portion k ₁ .

However, particularly preferred is the in Fig. 1 illustrated embodiment in which tangentially to the circular arc-shaped portion k ₁ in the direction of the first intersection S _1, a third rectilinear section g ₃ connects, which includes with the axis of symmetry s an angle γ smaller than 90 degrees. (here the angle γ is about 72 degrees). This results in a good weldability of the crane arm, better Spannbarkeit for welding through the obliquely meeting sections and the possibility of performing a longitudinal weld without additional edge preparation. Overall, a process-reliable training results.

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

In the in the Fig. 1 illustrated embodiment, the center of curvature K of the circular arc-shaped portion k _{1 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 always be in the area between the center M and the first intersection S ₁ .

At the circular arc-shaped portion k ₁ connects in the direction of the second point of intersection S ₂ tangentially to the in Fig. 1a and 1b illustrated auxiliary circle of the first rectilinear section g ₁ , which extends over the majority of the contour curve between the center M and the second intersection S ₂ . 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 g _{1 of} the rectilinear portion g ₁ (see Fig. 1b ) encloses an acute angle β with the symmetry axis s, which is approximately 18 degrees in the exemplary embodiment shown. In general, the acute angle β can also be 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 g ₁ .

In the embodiment according to Fig. 1 Close to the first rectilinear section g ₁ directly to a second rectilinear section g ₂ , which extends to the axis of symmetry s, there ends in an edging 7 and this intersects in the second intersection S ₂ . As this particular in Fig. 1c can be seen, it may be desirable for manufacturing reasons, if the second rectilinear section g ₂ (unlike in Fig. 1a shown) not directly, but is connected via a preferably curved formed further portion with the first rectilinear portion g ₁ .

At the in Fig. 1 illustrated embodiment, 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 the 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.

The second rectilinear portion g ₂ , which ends in a curve in the form of a Kantung 7, has the advantage that thereby in the area around the top of the crane arm around a favorable local force introduction, such as in the support of Gleitpaketen between each boom extensions takes place. 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 is prevented in the upper area.

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 Fig. 3 ) _. Such training does not form part of the invention. However, this represents only a special variant of the more general idea, namely that the contour line ends in a rounding at the symmetry line s. As an alternative 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, as in FIG Fig. 1 shown.

More generally, for all embodiments of the crane according to the invention, it must be said that the centroid F, of the area enclosed by the contour line in the transverse plane, lies in a region between the plane Center M and the first intersection S ₁ , that is below half the height of the crane arm is located. 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 S ₁ , 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, particularly preferably 2.75 times as large as the distance e. The distance D may each be less than three times the distance e.

It can be provided that the distance d of the contour line from the symmetry axis s at approximately one 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 is.

At the in Fig. 1 illustrated embodiment, 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 in Fig. 1a the course shown has the contour line only a single extreme point E, that is, 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. When approaching the arcuate portion k ₁ by a polygon, as in Fig. 1c Of course, all the points of the polygon section through which the circular arc-shaped section k _{1 is} approximated in the region of the extreme point E exhibit this maximum distance e.

Starting from the in Fig. 1a shown auxiliary circle with the radius r, the embodiment according to Fig. 1 a profile width b according to b ~2r, a profile height D according to D -3r and a profile width above b ₁ according to b ₁ -r on. This particular Advantageous dimensions can be provided quite generally in crane arms according to the invention.

The Fig. 1e shows for the embodiment of Fig. 1 the position of the centroid F between the center M and the first intersection S ₁ on the axis of symmetry s. The centroid F refers to the in Fig. 2 dash-dotted area, ie on the entire surface, 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, wherein 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 illustrated embodiment is meant to be 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 is for example a boom extension arranged in a boom. Of importance is that the arcuate section k ₁ 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 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 would be particularly preferred to provide the crane arm, at least along a portion of its longitudinal extent, from a single sheet which is suitably shaped and subsequently closed along a single line (for example, welded) is. This line can run, for example, in the area of the first intersection point S ₁ 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.

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

In Fig. 5 By way of example, a commercial vehicle 3 is shown 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 (13)

1. A crane boom for a crane (4) having a longitudinal axis and a notional contour line which extends in a transverse plane relative to an axis of symmetry (s) in at least approximately mirror-symmetrical relationship and is of a straight configuration at least portion-wise, wherein the contour line intersects the axis of symmetry (s) at a first and a second intersection point (S₁, S₂) and narrows in the direction of the second intersection point (S₂) at least before the last third of the spacing between the first and second intersection points (S₁, S₂), wherein the narrowing of the contour line continues to the second intersection point (S₂) and ends in a rounded configuration at the line of symmetry (s), wherein the contour line between the first intersection point (S₁) and a center point (M) arranged equidistantly relative to the first and second intersection points (S₁, S₂) has at least partially an at least approximately arcuate portion (k₁) which is preferably in the form of a quarter-circle arc and that the center point of curvature (K) of the arcuate portion (k₁) is on or in the proximity of the axis of symmetry (s) and is preferably between the first intersection point (S₁) and the center point (M), and wherein the contour line has a straight portion (g₁) whose notional extension (g₁) in the direction of the second intersection point (S₂) intersects the axis of symmetry (S) at an angle (β), characterized in that a second straight portion (g₂) which ends in the rounded configuration adjoins the first straight portion (g₁).
2. A crane boom as set forth in claim 1, characterised in that the rounded configuration is in the form of an edge configuration (7).
3. A crane boom as set forth in claim 1 or 2, characterised in that either the second straight portion (g₂) directly adjoins the first straight portion (g₁) or that the second straight portion (g₂) is connected with the first straight portion (g₁) via a preferably curved further portion.
4. A crane boom as set forth in claim 3, characterised in that the acute angle (β) is greater than 10 degrees, preferably greater than 15 degrees and preferably smaller than 25 degrees.
5. A crane boom as set forth in one of claims 1 through 4, characterised in that the straight portion (g₁) is in the form of a tangential extension of the arcuate portion (k₁).
6. A crane boom as set forth in one of claims 1 through 5, characterised in that the arcuate portion (k₁) is approximated by a polygon.
7. A crane boom as set forth in one of claims 1 through 6, characterised in that the crane boom comprises at least one metal sheet and the metal sheet thickness of all portions (k₁, k₂, g₁, g₂, g₃) of the crane arm in the transverse plane is at least substantially equal in magnitude.
8. A crane boom as set forth in one of claims 1 through 7, characterised in that the crane boom comprises two shells which are shaped in mirror-image relationship with each other and are joined to each other - preferably in the region of the first intersection point (S₁) and the second intersection point (S₂).
9. A crane boom as set forth in one of claims 1 through 7, characterised in that the crane boom at least along a portion of its longitudinal extent comprises a single metal sheet which is closed along a single line which extends preferably in the region of the first intersection point (S₁) or the second intersection point (S₂).
10. A jib system for a crane, characterised in that at least one jib and/or jib extension is in the form of a crane boom as set forth in one of claims 1 through 9.
11. A jib system as set forth in claim 10, characterised in that the shapes of the contour line of the jib and the contour lines of all jib extensions are the same - possibly except for the degree of approximation of circular arcs by polygons.
12. A crane, in particular a loading crane, characterised by a crane boom as set forth in one of claims 1 through 9 or a jib system (5) as set forth in claim 10 or 11.
13. A utility vehicle (3) having a crane (4) as set forth in claim 12.

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