Crane Jib Profile Shape for Weldability

Solution Overview

Problem

The production of arcuate sections in crane arms is complex and prone to errors, affecting weldability and overall manufacturing reliability.

Innovation Solution

A crane arm design featuring an arcuate section that can be approximated by a polygon or formed through rolling, with specific angles and connections allowing for improved weldability and tensioning, enabling a reliable longitudinal weld seam without additional edge preparation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If an arcuate section is used in the crane arm contour line, then the structural strength and buckling resistance are improved, but the manufacturing complexity and production errors increase

Engineering Contradiction:

Improvestructural strengthVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The contour line is divided into distinct sections: an arcuate section for structural strength and rectilinear sections for simplified manufacturing. The arcuate section is segmented into multiple points (first, second, third points of intersection) that define its geometry through straight line connections, making it manufacturable while maintaining the curved shape's structural benefits.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs an arcuate (curved) section in the contour line to provide structural strength and resistance against buckling. The curvature is defined by specific geometric relationships between intersection points with the axis of symmetry, creating a balanced profile that combines curved structural benefits with straight-line manufacturing simplicity.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Stability of the object's composition

If the arcuate section is produced using traditional methods, then the structural integrity is maintained, but the weldability and production reliability deteriorate

Engineering Contradiction:

Improvestructural integrityVSAvoidproduction reliability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The contour line is divided into distinct sections: an arcuate section for structural strength and rectilinear sections for simplified manufacturing. The arcuate section is segmented into multiple points (first, second, third points of intersection) that define its geometry through straight line connections, making it manufacturable while maintaining the curved shape's structural benefits.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent specifies precise geometric parameters for the arcuate section, including the positions of intersection points with the axis of symmetry and the angles formed by the rectilinear sections. These parameter definitions enable consistent reproduction of the profile through standard manufacturing processes, improving production reliability while maintaining structural integrity.

Inventive Principle:

Principle #35Parameter changes

3Strength

If additional edge preparation is performed for welding, then the weld quality is improved, but the manufacturing time and process complexity increase

Engineering Contradiction:

Improveweld qualityVSAvoidmanufacturing time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The contour line is divided into distinct sections: an arcuate section for structural strength and rectilinear sections for simplified manufacturing. The arcuate section is segmented into multiple points (first, second, third points of intersection) that define its geometry through straight line connections, making it manufacturable while maintaining the curved shape's structural benefits.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The profile geometry is designed in advance with the arcuate and rectilinear sections arranged to provide inherent welding suitability. The specific angular relationships between sections are built into the design, allowing longitudinal weld seams to be executed directly without requiring additional edge preparation steps, thus saving manufacturing time while ensuring weld quality.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP2185462B1Profile shape for a crane jib

Publication Date: 2011.03.09 PALFINGER AG

Figure 1a~1d
Figure 1e~1f
Figure 1g~2

AI summary

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 having an at least approximately arcuate section (k1) between a center (M) that is equally interspaced from the first and second point of intersection (S1, S2) on the axis of symmetry (s) and the first point of intersection (S1), a first straight section being tangentially contiguous thereto in the direction of the second point of intersection (S2), the imaginary extension of which first straight section in the direction of the second point of intersection (S2) intersects the axis of symmetry (s) and forms an acute angle therewith. The invention is characterized in that a second straight section (g2) is tangentially contiguous to the approximately arcuate section (k1) in the direction of the first point of intersection (S1) and extends up to the axis of symmetry (s) and forms an angle (?) of less than 90 degree with said axis of symmetry in the first point of intersection (S1) in the interior of the surface enclosed by the contour line.