Rail Screw Coupling Groove Retaining Ring
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Solution Overview
Problem
Existing screw coupling systems for rail vehicles face issues with unscrewing protection, including heat-induced material changes, complex manufacturing processes, and accidental loosening of locking mechanisms, which can lead to damage and safety risks.
Innovation Solution
A screw coupling system with a groove-based unscrewing lock featuring a locking ring and a retaining ring that is radially positioned and closed over its circumference, preventing the locking ring from sliding out and requiring no material connection to the threaded rod, thus avoiding heat input and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a washer is welded to the end of the threaded rod, then unscrewing protection is achieved, but heat is introduced into the threaded rod causing adverse structural changes and requiring extensive preparation and specially trained welders
Solution Approach 1:
A groove is introduced as an intermediary structure in the threaded rod, into which a retaining ring is placed. This groove-based system provides unscrewing protection without requiring welding, thus avoiding heat input and structural changes in the threaded rod while simplifying the manufacturing process.
Solution Approach 2:
The welding process is replaced with a mechanical retention system. Instead of welding a washer to the threaded rod, a retaining ring is mechanically held in place within a groove through friction and geometric constraints, eliminating the need for thermal joining and specialized welders.
2Reliability
If a cotter pin or roll pin is used as anti-screw device, then unscrewing protection is provided, but there is a risk that the anti-screw device will accidentally be released from its holder
Solution Approach 1:
The retaining ring is nested within the groove of the threaded rod, with the groove acting as a containment structure. This nested arrangement ensures that the retaining ring remains securely in place and cannot accidentally be released, while still providing effective unscrewing protection.
Solution Approach 2:
The groove serves as an intermediary structure that holds the retaining ring in place. This intermediate feature provides a reliable retention mechanism that prevents accidental release of the anti-screw device while maintaining its protective function.
3Reliability
If a spring-loaded ring is used as anti-screw device, then unscrewing protection is achieved, but a moment acting on the spring-loaded ring may push it out of the groove
Solution Approach 1:
The groove is designed as a precise intermediary structure that accommodates the retaining ring. The geometric constraints of the groove prevent the ring from being pushed out, providing stable retention without requiring complex spring mechanisms.
Solution Approach 2:
The spring-loaded mechanism is replaced with a passive retaining ring held in place by the groove geometry. This substitution eliminates the risk of the ring being pushed out by moments while maintaining effective unscrewing protection through simple mechanical retention.
4Strength
If the threaded rod is made of high-strength tempered steel, then strength is improved, but heat from welding can lead to adverse structural changes in the threaded rod material
Solution Approach 1:
The welding process is replaced with a mechanical retention system using a groove and retaining ring. This substitution eliminates heat input during assembly, preserving the structural integrity and material properties of the high-strength tempered steel threaded rod.
Solution Approach 2:
The groove-based retention system acts as an intermediary that provides unscrewing protection without requiring thermal joining. This approach allows the threaded rod to maintain its high-strength tempered steel properties without adverse structural changes from welding heat.
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a screw coupling for coupling two rail vehicles, comprising a threaded rod which has a respective coupling element in the region of each of the axial ends of the threaded rod. At least one of the coupling elements or both coupling elements is/are screwed onto an outer thread of the threaded rod, and the threaded rod can be rotated in order to thereby vary the distance between the two coupling elements. The screw coupling also comprises at least one unscrewing protection mechanism at the threaded rod axial end on which the coupling element is screwed, said unscrewing protection mechanism blocking the coupling element from unscrewing over the axial end of the threaded rod, and the unscrewing protection mechanism comprises a groove which extends at least over a section of the circumference of the threaded rod and into which a securing ring protruding radially out of the groove is inserted, wherein the circumference of the securing ring is interrupted at least at one location. The screw coupling according to the invention is characterized in that a holding ring with a closed circumference is arranged on the securing ring radially outwards, said holding ring enclosing the entire circumference of the securing ring.