Mobile Crane Pivotable Counterweight Radius Adjustment
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Solution Overview
Problem
Larger mobile cranes cannot transport and assemble counterweight devices on public roads due to size constraints, limiting the adjustability of counter-torque during operation and requiring complex assembly processes, which is inefficient and costly.
Innovation Solution
A mobile crane design with a pivotable counterweight device that adjusts the counterweight radius linearly relative to the upper carriage axis, using a combination of pivotable arms and coupling elements, allowing for flexible counter-torque adjustment without requiring additional space, and can be controlled via a hydraulic system for centralized operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the counterweight device is made larger to increase counter-torque, then the counter-torque increases, but the crane cannot be transported on public roads and requires complex assembly/disassembly
Solution Approach 1:
The counterweight device is divided into modular counterweight elements that can be selectively assembled on the counterweight base plate. This allows the crane to be configured with different counterweight masses as needed, and the modular structure enables easy assembly and disassembly for transport on public roads without requiring the entire counterweight device to be permanently attached.
Solution Approach 2:
The counterweight radius is made variable through a telescopic or adjustable support structure that allows the counterweight elements to be positioned at different radial distances from the upper carriage axis of rotation. This dynamic adjustment enables the counter-torque to be optimized for different lifting operations while maintaining a compact configuration for transport when counterweight elements are removed or repositioned.
2Device complexity
If the counterweight device is fixed in position to simplify structure, then the structure is simpler, but the counter-torque cannot be adjusted during operation
Solution Approach 1:
The support structure for the counterweight elements is designed to be adjustable rather than fixed, allowing the radial position of the counterweight elements to be changed during operation. This enables the operator to optimize the counter-torque by repositioning counterweight elements to different distances from the rotation axis as lifting requirements change, while maintaining a relatively simple overall structure.
Solution Approach 2:
The ballasting device serves multiple functions: it provides the lifting mechanism to raise counterweight elements onto the upper carriage, it positions the counterweight elements at various radial positions to adjust counter-torque, and it secures the counterweight elements during operation. This multi-functionality reduces the need for separate specialized mechanisms.
3Area of stationary object
If counterweight elements are positioned closer to the rotation axis to save space, then the space requirement is reduced, but the counter-torque decreases
Solution Approach 1:
The radial position of the counterweight elements is made variable, allowing them to be positioned closer to the rotation axis when space is constrained or farther from the axis when maximum counter-torque is needed. The adjustable support structure enables this dynamic repositioning during operation to optimize both space utilization and counter-torque generation as requirements change.
4Ease of operation
If the counterweight device is made detachable for transport, then transport on public roads is enabled, but the assembly process becomes more complex
Solution Approach 1:
The counterweight device is segmented into the counterweight base plate and separate counterweight elements that can be independently handled. The base plate remains permanently attached to the upper carriage with simplified mounting, while individual counterweight elements can be added or removed as needed. This segmentation enables transport on public roads with reduced counterweight configuration while minimizing assembly complexity through standardized connection interfaces.
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
Enables flexible adjustment of counter-torque during operation without needing additional space, simplifies assembly and transport, and optimizes the undercarriage design by allowing counterweight radius adjustment during operation rather than setup, improving operational efficiency and reducing complexity and cost.
Implementation Method 1
the ballasting device usually comprises one or more hydraulic ballasting cylinders that extend downwards, are brought into engagement with the connecting elements of the counterweight device and lift the counterweight device onto the upper carriage by retracting
Implementation Method 2
the counterweight applies a counter-torque to the load torque via a lever arm and therefore rotates with the upper carriage
Data Source
AI summary
A mobile crane comprising a moveable undercarriage, an upper carriage mounted on the undercarriage so as to rotate about a vertical upper carriage axis of rotation and having a ballasting device, and a counterweight device that can be coupled to the ballasting device and comprises a counterweight base plate and at least one connecting element extending from the counterweight base plate for lifting and coupling the counterweight device to the ballasting device. The first arm in the ballasted state is connected to the counterweight base plate via a pivotable coupling element, which is pivotably mounted relative to the first arm and the counterweight base plate in such a way that the counterweight base plate can be adjusted in a linear movement radially to the upper carriage axis of rotation by simultaneously pivoting the first arm and the coupling element.