Crane Counterweight Fixing Device with Segmented Carrier Bar
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Solution Overview
Problem
Conventional counterweight fixing methods for cranes, especially slewing tower cranes with luffing jibs, are prone to noise nuisance and lack precision and safety due to sliding counterweights and require precise adaptation to individual crane models, leading to increased complexity and risk of counterweight blocks tipping or rotating during operation.
Innovation Solution
A counterweight fixing system featuring a carrier bar arranged at right angles to the counter jib with connecting struts and a transverse rail with recesses for plug-in pins, allowing counterweight blocks with a U-shaped cross-section to be hooked onto the carrier bar, providing generous tolerances and a locking mechanism to secure the plug-in pins, thus preventing rotation and ensuring stable attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If counterweights are laid into a basket on the counter jib, then the mounting process is simplified, but disturbing noises are generated due to movement of counterweights back and forth in the basket
Solution Approach 1:
The counterweight system is segmented into individual counterweight blocks that can be independently positioned and secured on the carrier bar, rather than placed as a collective mass in a basket. This segmentation allows each block to be firmly fixed in its designated position, eliminating the sliding and knocking movements that generate noise.
Solution Approach 2:
The patent introduces an intermediary fixing mechanism consisting of fixing elements with engagement portions that interact with corresponding features on the counterweight blocks. This intermediary system mediates between the counterweight blocks and the carrier bar, providing secure positioning that prevents movement and noise generation during operation.
2Reliability
If plug-in pins are used to hook counterweight blocks onto the counter jib with notches, then the attachment is more secure, but high precision is demanded during the mounting process
Solution Approach 1:
The patent changes the geometric parameters of the engagement interface between the fixing elements and counterweight blocks. The engagement portion of the fixing element is designed with specific dimensional relationships to the corresponding features on the counterweight blocks, creating a self-aligning connection that tolerates variations in positioning while maintaining secure attachment.
Solution Approach 2:
The fixing system incorporates dynamic adjustment capabilities where the fixing elements can be positioned at different locations along the carrier bar and the engagement portions can accommodate slight misalignments. This dynamic flexibility allows for reliable attachment without requiring high precision during the mounting process.
3Ease of operation
If counterweight blocks are allowed to have play in the direction of the longitudinal axis of the counter jib, then the demands for precision during mounting are reduced, but the plug-in pins perform partial rotation during angle changes generating noise
Solution Approach 1:
The patent extracts the rotational degree of freedom that causes noise by designing the engagement mechanism to constrain counterweight blocks against rotation. The fixing elements are specifically configured to prevent partial rotation during angle changes, removing this harmful motion while maintaining the desired play along the longitudinal axis for ease of mounting.
4Manufacturing precision
If the counterweight fixing system is precisely adapted to individual crane models, then the fit is optimal, but the complexity and number of different components increases
Solution Approach 1:
The patent designs the carrier bar, fixing elements, and counterweight blocks as universal components that can be applied across different crane models. The standardized interface and modular design allow the same component set to accommodate various crane configurations, eliminating the need for model-specific adaptations and reducing the total number of different components required.
Data Source
AI summary
Counterweight fixing device (1) for a crane, which is comparatively easy to install and can also be used in particular for cranes with a derricking jib, in which the derricking jib is rigidly connected to the mast (3), and at the same time provides a safe design without generating a high noise level during operation. The core principle of the design of the counterweight fixing device (1) is that the counterweight blocks (4) are simply suspended on a carrier bar (2), but the generation of noise is kept to a low level due to the suppression of the freedom of movement of the counterweight blocks (4).