Rail Vehicle Retractable Step Winter Ice Prevention
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Solution Overview
Problem
Sliding step arrangements for rail vehicles, when mounted below the car body, are not suitable for winter conditions due to freezing issues caused by snow and ice, leading to sluggish mechanisms and the need for fixed steps, which are less comfortable and pose safety concerns.
Innovation Solution
The sliding step arrangement incorporates a motor-driven mechanism with variable power output, where high power is initially applied to break through ice and snow, followed by reduced power for the remaining travel path, and includes a heating device, obstacle detection, and sealing features to prevent icing and ensure reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the sliding step arrangement is mounted below the car body to minimize space usage, then the space utilization is improved, but the mechanism becomes susceptible to freezing and ice accumulation in winter conditions
Solution Approach 1:
The heating device is activated before the sliding step mechanism operates in winter conditions to prevent ice and snow from accumulating on the step surface and rails, thereby maintaining reliability without requiring the mechanism to be relocated from its space-efficient position below the car body
Solution Approach 2:
The high power phase of the motor is activated at the beginning of the step's movement to break through any ice or snow accumulation that may have formed, ensuring the mechanism can reliably initiate movement even in freezing conditions
2Reliability
If fixed steps are mounted to ensure winter suitability, then the winter operability is improved, but the vehicle limit is exceeded and safety concerns arise
Solution Approach 1:
The mechanical fixed step system is replaced with a motor-driven sliding step mechanism that uses controlled force application (high power phase) to overcome ice and snow resistance, allowing the step to be retractable and compliant with vehicle width limits while maintaining winter operability
3Reliability
If high power is continuously applied to break ice and snow, then the winter operability is improved, but the energy consumption increases
Solution Approach 1:
The motor's power delivery is segmented into two distinct phases: a high power phase at the beginning of movement to break through ice and snow accumulation, and a standard power phase for the remainder of the travel path, thereby providing ice-breaking capability only when necessary and reducing overall energy consumption
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
This solution ensures the sliding step arrangement remains operational and safe in extreme winter conditions by effectively breaking ice and snow, preventing freezing, and maintaining functionality without exceeding vehicle limits.
Implementation Method 1
EP 1 386 818 A discloses a sliding step arrangement with a heater for the step surface
Implementation Method 2
DE 20 2006 017 930 U1 also discloses a loading ramp for a bus, the top of which is provided with a heating mat in order to keep the ramp free of ice under winter conditions
Data Source
Figure 1
Figure 2a~2b
AI summary
The invention relates to a retractable step arrangement (1) for a rail vehicle having a housing (2), which can be fastened to a car body of the rail vehicle and which has a housing opening (2a), and having a step (3), which is movably supported in the housing (2) in an initial position (I) and which can be extended through the housing opening (2a) from the initial position (I) into at least one final position (II, II') in an extension direction (A) and which can be retracted from the at least one final position (II, II') into the initial position (I) against the extension direction (A). In order to ensure the winter suitability even under extreme conditions, the invention proposes that the retractable step arrangement (1) comprise at least one means (4, 9, 10, 11a, 11b, 12, 13) for preventing the step (3) from becoming frozen in place.