Lifting Rigging with Constant Torque Springs for Yoke Stability
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Solution Overview
Problem
Lifting heavy and unwieldy loads in confined spaces using column-mounted slewing cranes is challenging due to the offset center of mass of T-shaped yokes, leading to tilting, oscillation, and potential damage or hazard, necessitating additional cranes or manual intervention, which increases costs and time.
Innovation Solution
A lifting rigging system with a weight-bearing assembly featuring constant torque springs and a calibrated yoke wire that stabilizes the yoke during initial lifting, ensuring it remains level by transferring its weight to the yoke wire before lifting the load off the ground, using a T-shaped yoke with hook and load lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a T-shaped yoke is used to lift heavy loads, then the lifting capacity is improved, but the yoke tilts and oscillates due to offset center of mass
Solution Approach 1:
A counterweight assembly is attached to the yoke at a position offset from the crane hook, comprising a spring element (constant torque spring) and a counterweight block. The spring element connects the counterweight block to the yoke, creating a counterbalancing moment that offsets the destabilizing effect of the yoke's offset center of mass. This allows the T-shaped yoke to maintain stability while lifting heavy loads.
Solution Approach 2:
The spring element is designed with specific mechanical properties (spring constant, pre-load) to provide the exact counterbalancing force needed. By adjusting the spring parameters and counterweight mass, the system achieves neutral equilibrium, transforming the yoke from an unstable configuration to a stable one during the lifting process.
2Stability of the object's composition
If two cranes are used to lift a single component, then the load stability is improved, but the overall cost and time consumption increase
Solution Approach 1:
The counterweight assembly acts as an intermediary mechanism between the single crane and the T-shaped yoke. It mediates the force transmission, providing the necessary counterbalancing moment that would otherwise require a second crane. This intermediary device enables stable lifting with a single crane, reducing system complexity.
Solution Approach 2:
The stabilizing function that would require a second crane is extracted and embodied in the counterweight assembly attached to the yoke. This separates the stabilization function from the need for additional lifting equipment, allowing a single crane to perform both lifting and stabilization functions.
3Stability of the object's composition
If a chain hoist is manually operated to keep the yoke balanced, then the yoke stability is improved, but the operational complexity and safety hazards increase
Solution Approach 1:
The counterweight assembly with the spring element provides automatic, passive counterbalancing. The spring element continuously exerts the counterbalancing force based on the yoke's position and load, without requiring manual operation or monitoring. The system self-regulates the balance, eliminating the need for technicians to manually operate chain hoists during the lifting process.
Solution Approach 2:
The spring element acts as an automatic intermediary mechanism that continuously adjusts the counterbalancing force as the yoke moves, replacing the need for manual intervention. This passive mechanical intermediary provides continuous stabilization without human involvement.
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 stable and safe lifting of heavy loads in confined spaces by maintaining the yoke horizontal and centered over the load's center of mass, reducing the need for multiple cranes and manual intervention, thus minimizing costs and hazards.
Implementation Method 1
a spring module comprising a number of constant torque springs
Implementation Method 2
the weight-bearing assembly is configured such that the fully-extended yoke wire bears the weight of the yoke
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention describes a lifting rigging (1) comprising a yoke (10) adapted for connection between a load (3) and a suspension point (20); and a weight-bearing assembly (14) mounted on the yoke (10), which weight-bearing assembly (14) comprises a spring module (140) comprising a number of constant torque springs (14S), and a yoke wire (141) with a first end adapted for connection to the suspension point (20) and a second end connected to the spring module (140) and adapted to wind the constant torque springs (14S) when the yoke wire (141) is subject to a pulling force (Fpull), and wherein the weight-bearing assembly (14) is configured such that the yoke wire (141) bears the weight of the yoke (10) when the lifting rigging (1) is suspended from the suspension point (20).