Knuckle Boom Crane Lateral Actuator Mounting
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Solution Overview
Problem
Conventional knuckle boom cranes for offshore applications have limitations in articulation angle and load capacity, particularly when hydraulic jacks are fully retracted or extended, due to their inherent design.
Innovation Solution
The design includes a knuckle boom with a main and terminal boom, each with lateral faces, and a downstream linear actuator fastened to one lateral face of the main boom and one of the terminal boom, providing an improved lever arm and increased articulation angle, and allowing enhanced load capacity by optimizing the buckling length and eliminating parasitic moments through universal and ball joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the downstream linear actuator is fastened between the opposite faces of the main boom and terminal boom, then the structure is simple, but the lever arm is reduced and articulation angle is limited to approximately 120°
Solution Approach 1:
The actuator is mounted on lateral faces of the booms rather than on opposite faces, changing the spatial dimension of attachment. This lateral mounting arrangement extends the lever arm perpendicular to the boom轴线, increasing the effective moment arm without requiring a more complex mounting structure
Solution Approach 2:
The actuator mounting creates an asymmetric configuration where the actuator is positioned on one side of the boom assembly rather than symmetrically between opposite faces. This asymmetric placement optimizes the lever arm geometry and enables greater articulation angles while maintaining structural simplicity
2Ease of manufacture
If the downstream linear actuator is fastened between opposite faces of the booms, then the mounting is straightforward, but the load capacity is reduced when the actuator is fully retracted or extended
Solution Approach 1:
By mounting the actuator on lateral faces rather than opposite faces, the load path is optimized. The lateral mounting position creates more favorable stress distribution and reduces bending moments on the actuator mounts, thereby increasing load capacity while keeping the mounting procedure straightforward
Solution Approach 2:
The invention changes the geometric parameters of the actuator mounting location and orientation. By positioning the actuator on lateral faces at specific distances from the articulation points, the mechanical advantage and structural strength are optimized for the full range of motion, including fully retracted and extended positions
3Volume of moving object
If conventional hydraulic jacks are used with standard articulation geometry, then the system is compact, but the articulation angle is limited to approximately 120°
Solution Approach 1:
The lateral mounting of the actuator creates an asymmetric geometry that allows the terminal boom to articulate through a wider angle range. The asymmetric placement of the actuator on lateral faces enables the boom to rotate beyond the conventional 120° limit while maintaining a compact overall assembly volume
Solution Approach 2:
The actuator mounting configuration allows for dynamic articulation through a wider range of angles. The lateral face mounting provides better mechanical leverage during the full range of motion, enabling the system to achieve and maintain stable articulation angles from approximately 30° to 150° while keeping the assembly compact
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the articulation angle and load capacity of the knuckle boom, particularly when the downstream linear actuator is fully retracted or extended, improving operational efficiency and stability.
Implementation Method 1
Such a configuration has in particular for interest to provide an improved lever arm between the main boom and the terminal boom
Implementation Method 2
the upstream assembly means in the form of a universal joint (also named cardan joint, hooke's joint or U-joint)
Implementation Method 3
to one of the lateral faces of said terminal boom through downstream assembly means in the form of a ball joint
Data Source
AI summary
Disclosed is a knuckle boom crane for offshore application, wherein the crane includes a knuckle boom, carried by a support structure and equipped with an operating unit. The knuckle boom includes a main boom and a terminal boom. The operating unit of the knuckle boom include at least one downstream linear actuator, arranged between the main boom and the terminal boom, for the rotational operation of the terminal boom about a downstream articulation axis. And the at least one downstream linear actuator is fastened to one of the lateral faces of the main boom and to one of the lateral faces of the terminal boom, in order to provide an improved lever arm between the main boom and the terminal boom.