Insulating Wedge Derails Crane Shoe to Cut Power
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Solution Overview
Problem
Existing bridge crane safety devices are inadequate in preventing operators from moving the crane outside the designated operating zone, leading to unintended movement and potential safety hazards.
Innovation Solution
A shoe derailment device with a wedge head made of electrically insulating material is positioned outside the operating zone along the conductor rail assembly, derailing the conductor shoe assembly and interrupting electrical power to the crane's motors when it moves beyond the zone, ensuring the crane stops operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If operator training is used to maintain crane movement within operating zone, then operational flexibility is maintained, but safety reliability deteriorates due to human error
Solution Approach 1:
The conductor shoe assembly acts as an intermediary mechanical element that physically connects the bridge crane to the conductor rail assembly. When the bridge crane moves outside the operating zone, the conductor shoe assembly is derailed from the conductor rail assembly by the shoe derailment device, automatically interrupting electrical power supply without requiring operator intervention or complex control systems.
Solution Approach 2:
The patent replaces operator-based manual control (human decision-making) with a mechanical safety system consisting of the shoe derailment device, wedge head, and conductor shoe assembly. This mechanical substitution eliminates human error while maintaining operational flexibility through the automatic nature of the derailing mechanism.
2Reliability
If shoe derailment device is positioned outside operating zone, then safety reliability is improved by automatic power interruption, but device complexity increases
Solution Approach 1:
The shoe derailment device is integrated with the existing conductor rail assembly infrastructure. The conductor shoe assembly, which already exists for power transmission, serves dual purposes: normal electrical contact within the operating zone and automatic derailing when the bridge crane exits the zone. This merging eliminates the need for separate, complex safety systems.
Solution Approach 2:
The conductor shoe assembly performs multiple functions: it provides electrical power transmission during normal operation and acts as a mechanical derailing element when the bridge crane moves outside the operating zone. The shoe derailment device with its wedge head and insulating body serves both as a positional limit and an electrical isolation mechanism, reducing overall system complexity.
3Reliability
If conductor shoe assembly is derailed using electrically insulating material, then electrical power interruption is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The shoe derailment device uses electrically insulating material specifically at the critical interface where the conductor shoe assembly contacts the wedge head. This localized application of insulating properties ensures reliable electrical power interruption only where needed, while the rest of the system maintains standard manufacturing tolerances. The insulating body with wedge head creates a precise mechanical and electrical boundary at the operating zone limit.
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
Effectively prevents the crane from moving outside the predetermined operating zone by automatically shutting off electrical power, enhancing safety by ensuring the crane remains within designated limits.
Implementation Method 1
a shoe derailment device having a wedge head provided at a longitudinal end of a body made of an electrically insulating material
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
The shoe derailment device for use in derailing a conductor shoe assembly of a bridge crane from a conductor rail assembly generally has a wedge head provided at a longitudinal end of a body made of an electrically insulating material, the shoe derailment device being securable to the conductor rail assembly in a derailment position in which the shoe derailment device is positioned outside an operating zone of the bridge crane, with the wedge head facing the operating zone in a manner that if the conductor shoe assembly is moved outside the operating zone, into the area occupied by the shoe derailment device, the conductor shoe assembly is derailed from the conductor rail assembly as the conductor shoe assembly engages the wedge head and is maintained in a derailed state by the electrically insulating material when the conductor shoe assembly is engaged with the body.