Crane Boom Asymmetric Triangular Cross-Section Nesting

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Solution Overview

Problem

Existing crane designs face challenges in reducing transport dimensions while maintaining torsional rigidity, with conventional methods either resulting in statically unfavorable and heavy booms or increasing weight and manufacturing costs with U-shaped or telescopic designs.

Innovation Solution

A crane boom with a modified triangular cross-section that allows two boom parts to be nested or pivoted, forming a right-angled or nearly right-angled triangle, enabling compact transport dimensions without compromising torsional resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the entire boom cross-section is reduced to meet road transport requirements, then transport dimensions are reduced, but the boom cross-section becomes statically unfavorable, heavier, and more elastic

Engineering Contradiction:
Improvetransport dimensionsVSAvoidboom cross-section strength
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The patent applies nesting by positioning one boom part inside another boom part during transport. The modified triangular cross-section with eccentric upper chord allows the booms to be nested compactly, reducing transport dimensions without requiring reduction of the boom cross-section itself, thereby maintaining structural strength.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent introduces asymmetry by modifying the triangular cross-section to have an eccentric upper chord that does not lie on the median line of the triangle. This asymmetric configuration enables the boom parts to be nested more compactly while maintaining favorable static properties and torsional rigidity.

Inventive Principle:
Principle #4Asymmetry

2Volume of moving object

If boom parts are pivoted relative to one another to reduce transport height, then transport height is reduced, but additional equipment components and effort are required

Engineering Contradiction:
Improvetransport heightVSAvoidequipment components
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

Instead of pivoting boom parts, the patent uses nesting where one boom part is positioned inside another. This eliminates the need for pivoting mechanisms, motors, and sliding drives, reducing device complexity while achieving compact transport dimensions.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Volume of moving object

If boom parts are designed as open U-shape to reduce transport height, then transport height is reduced, but boom weight and manufacturing cost increase

Engineering Contradiction:
Improvetransport heightVSAvoidboom weight
Core Design Contradiction:
Volume of moving objectVSWeight of moving object

Solution Approach 1:

The patent uses an asymmetric modified triangular cross-section with an eccentric upper chord instead of a symmetric U-shape. This asymmetric design enables compact nesting for transport while using fewer materials than the U-shape, thereby reducing boom weight and manufacturing cost.

Inventive Principle:
Principle #4Asymmetry

4Volume of moving object

If open U-shape boom parts are used to reduce transport dimensions, then transport dimensions are reduced, but torsional flexibility increases making them unsuitable for high wind speeds

Engineering Contradiction:
Improvetransport dimensionsVSAvoidtorsional resistance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent employs an asymmetric modified triangular cross-section with grating connections that maintain torsional rigidity. Unlike open U-shapes, this closed asymmetric triangular configuration provides excellent torsional resistance while still enabling compact nesting for transport.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent achieves compact transport dimensions through nesting of boom parts with the modified triangular cross-section, rather than relying on open U-shapes. This nesting approach allows the use of torsionally rigid closed sections while maintaining reduced transport dimensions.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP2976287B1Crane boom and crane
Publication Date: 2019.03.06 LIEBHERR WERK BIBERACH GMBH
  • EP2976287B1 patent drawingFigure 1~2
  • EP2976287B1 patent drawingFigure 3~4
  • EP2976287B1 patent drawingFigure 5~6

AI summary

The invention relates to a crane boom for a crane, said crane boom consisting of an upper beam and two lower beams which are connected to each other by means of latticework and form a triangular boom cross-section, the boom cross-section comprising, at least in sections, a triangular cross-sectional shape in which the upper beam extends eccentrically. The invention also relates to a crane having such a crane boom.