Railroad Switch Locking Bearing Screw Anti-Rotation Design
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Solution Overview
Problem
The existing methods for mounting a pawl lock on a railroad switch require high torque and alignment precision, leading to stress on components and potential twisting of the adjusting tongue, which can result in undesirable gaps between the tongue and the rail, potentially causing train wheel collisions.
Innovation Solution
A locking bearing screw with a spring assembly or an anti-rotation ring with external teeth is used to simplify the assembly process, allowing for a narrower torque range and easier alignment with a locking plate, reducing stress on components and preventing twisting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the locking clip screw is tightened with maximum torque and secured with a locking plate, then the locking bearing is firmly fixed to the adjusting tongue, but the high torque and alignment precision required cause stress on components and may lead to twisting of the adjusting tongue
Solution Approach 1:
The locking mechanism is divided into separate functional elements: a locking bearing screw for securing the locking bearing to the adjusting tongue, and a locking plate for additional reinforcement. This segmentation allows each component to be optimized independently, with the screw designed for controlled torque application and the plate providing distributed load bearing, thereby reducing stress concentration on individual components while maintaining firm locking.
2Strength
If the locking clip screw requires precise alignment with the locking plate hole, then the locking connection is secure, but the alignment precision requirement increases the complexity of the assembly process
Solution Approach 1:
The locking plate is pre-formed with a hole that is intentionally slightly larger than the screw head diameter, and the screw is designed with a head that can be inserted at various angles. This preliminary design feature allows the assembly to be initiated without precise alignment, and the locking action is completed through the engagement of the screw head with the plate hole during the tightening process, thereby simplifying the assembly operation while maintaining secure locking.
3Reliability
If the adjusting tongue is firmly connected to the rail via the locking pawl, then the tongue is held in position, but the connecting components are subjected to high forces that may cause twisting and lifting of the tongue from the rail
Solution Approach 1:
A locking bearing is introduced as an intermediary component between the adjusting tongue and the locking pawl. This bearing distributes the high forces from the pawl-rail connection across a larger area of the tongue and provides a stable mounting point. The bearing's structured design with a mounting hole and locking features allows it to withstand the forces without transmitting twisting moments to the tongue, thereby maintaining the stability of the tongue-rail connection while ensuring reliable positioning.
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
The solution enables a secure and stress-free mounting of the locking bearing with reduced torque requirements and improved alignment, preventing twisting and ensuring a stable connection between the adjusting tongue and the rail.
Implementation Method 1
a spring assembly (14) arranged between the foot and the screw head (13) of the locking bearing screw (11)
Implementation Method 2
a non-rotating ring with external teeth (16) surrounding the head (13) of the locking bearing screw (11)
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a~4d
AI summary
The lock bearing (7) has a lock bearing screw that penetrates a foot of a setting tongue (4) with a head. A locking device adapter encloses the head of lock bearing screw in an annular manner with an outer toothing. A safety plate (12) is provided with an inner toothing matched for receiving outer toothing of locking device adapter.