Railway Pantograph Interlock with Electrical and Pneumatic Key Sequencing

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Solution Overview

Problem

Existing high-voltage interlock systems for railway vehicles are not compatible with the new electric grounding switches on modern trains, requiring manual operations that complicate maintenance and pose safety risks.

Innovation Solution

A high-voltage interlock device and method that simultaneously cuts off the pantograph-raising circuit and main circuit breaker using electric grounding keys, followed by pneumatic circuit disconnection and safety key removal, ensuring safe non-electrified operations through a three-stage key interlock system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If manual operations are used with existing key interlock systems, then compatibility with new electric grounding switches is achieved, but maintenance complexity increases and safety risks arise

Engineering Contradiction:
Improvecompatibility with new electric grounding switchesVSAvoidmaintenance operation complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent replaces manual mechanical key operations with an automated control system. The key switch automatically controls the grounding switch and pneumatic valve through electrical circuits, eliminating the need for manual key rotation and coordination between multiple components. This substitution of mechanical manual operations with an automated electrical control system resolves the contradiction by maintaining compatibility while dramatically simplifying the operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system enables self-service automation where the key switch automatically triggers the grounding switch closure and pneumatic valve actuation without requiring manual intervention. The interlock logic is built into the circuit design, allowing the system to service itself through automatic sequence execution when the key is inserted or removed, thereby reducing operational complexity while maintaining full compatibility.

Inventive Principle:
Principle #25Self-service

2Reliability

If separate locking of pantograph pneumatic circuit and grounding switch is implemented, then comprehensive safety is achieved, but device complexity increases

Engineering Contradiction:
Improvehigh-voltage safety protectionVSAvoidinterlock system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the separate control of the grounding switch and pneumatic valve into a single integrated key switch mechanism. Both functions are controlled through one unified device with interconnected circuits, where the key switch simultaneously manages the electrical grounding and pneumatic isolation. This consolidation maintains comprehensive safety by preserving both protection functions while reducing the overall device complexity through integration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The key switch is designed as a universal multi-functional device that simultaneously controls multiple safety functions: it operates the grounding switch, actuates the pneumatic valve, and provides interlock protection. This single component performs what previously required multiple separate devices and manual coordination steps, thereby maintaining high-voltage safety while simplifying the interlock system structure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If multiple keys (Key A and Key B) are used for interlock operations, then safety interlocking is achieved, but ease of operation deteriorates

Engineering Contradiction:
Improvecircuit interlocking safetyVSAvoidmaintenance operation simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent combines the functions of multiple separate keys (Key A for grounding switch and Key B for interlock box) into a single unified key switch. This single key simultaneously controls both the grounding function and the pneumatic circuit isolation, eliminating the need for operators to manually coordinate multiple key operations. The circuit interlocking safety is maintained through integrated electrical connections that ensure both functions are activated together, while operational simplicity is dramatically improved by reducing the number of manual steps.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4682011A1High-voltage interlock device and high-voltage interlock method for railway vehicle, and railway vehicle
Publication Date: 2026.01.21 CRRC CHANGCHUN RAILWAY VEHICLES CO LTD
  • EP4682011A1 patent drawingFigure 1~3
  • EP4682011A1 patent drawingFigure 4~5
  • EP4682011A1 patent drawingFigure 6

AI summary

A high-voltage interlock device and high-voltage interlock method for a railway vehicle, and a railway vehicle. When an electric grounding key on a cab fault switch panel of the high-voltage interlock device is rotated to a locked position, a first-stage electric grounding key is unlocked; when the electric grounding key is inserted into a pantograph-lifting pneumatic circuit interlock box, and a first three-way valve handle (t1) is rotated to a pneumatic circuit cut-off position, a second-stage pneumatic circuit key is unlocked; and when the second-stage pneumatic circuit key is inserted into a locking device (300) and rotated, a converter box key (c) and a power supply box key (d) are unlocked. The high-voltage interlock method for a railway vehicle is applied to the high-voltage interlock device of a railway vehicle; and the railway vehicle comprises the high-voltage interlock device. In the device, double locking of circuits and pneumatic circuits is performed on a pantograph, such that the pantograph can be prevented from being electrified during maintenance, a main circuit breaker is prevented from being closed, a pantograph pneumatic circuit is prevented from being lifted during maintenance, and thus the operation for maintenance staff members is simplified, and the safety level of operation is improved.