Switch Point Coupling Assembly for Fretting and Thermal Stress
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Solution Overview
Problem
Traditional switch point systems are prone to sudden breakage due to fretting and surface wear, and fail to efficiently compensate for thermal dimensional variations and misalignments, leading to increased tensions and breakages.
Innovation Solution
The proposed assembly includes a manoeuvre group with a coupling element connected to a manoeuvre hook through a sliding seat that allows for thermal expansion tolerance and residue removal, and a control group with a rotatable arm to ensure correct movement and reduce fretting, using a metal-plastic coupling with a nickel-chromium-molybdenum steel and Polyamide 66 combination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional rigid coupling systems are used to connect tie rods to blades, then structural strength is maintained, but fretting and surface wear occur leading to sudden breakage
Solution Approach 1:
The patent replaces rigid fixed connections with dynamic articulated connections using pivots and pins that allow controlled movement. The coupling element with pivot (point P) enables the leg to rotate and adjust during operation, transforming the static rigid structure into a dynamic system that can accommodate movements and reduce fretting between components.
Solution Approach 2:
The patent changes the physical state and properties of contact surfaces by introducing curved contact surfaces and spherical interfaces instead of flat rigid contacts. This parameter change in surface geometry allows for rolling motion and reduces sliding friction, thereby minimizing fretting and material removal at contact points.
2Manufacturing precision
If fixed connection points are used between coupling elements and blades, then positioning precision is achieved, but thermal expansion and contraction cause excessive tensions
Solution Approach 1:
The articulated connection with pivot points allows the coupling system to dynamically adjust to thermal expansions and contractions. The leg can rotate around the pivot, accommodating length variations of the blade due to thermal effects without generating excessive tensions, while still maintaining precise operational positioning.
Solution Approach 2:
The pivot point acts as an intermediary element between the fixed blade and the moving coupling elements. This mediator allows relative movement and absorbs thermal stresses, preventing the transmission of excessive forces through the entire structure while maintaining functional connectivity.
3Object-affected harmful factors
If closed coupling structures are used to protect internal components, then protection is provided, but residues and dirt accumulate accelerating wear
Solution Approach 1:
The patent extracts and removes the harmful accumulation of residues by designing open coupling structures where contact points are exposed to the external environment. The pivot connections and open joints allow dirt and wear particles to be washed away by passing trains rather than accumulating and accelerating fretting between components.
4Stability of the object's composition
If multiple rigid connection points are used to ensure stable blade movement, then movement stability is achieved, but the system cannot compensate for misalignments and distortions
Solution Approach 1:
The system uses multiple articulated connections with pivot points instead of rigid fixed connections. Each joint can rotate and adjust independently, allowing the structure to adapt to misalignments and distortions while maintaining stable overall movement. The degrees of freedom provided by each pivot enable the system to accommodate various operational conditions.
Solution Approach 2:
The coupling system is segmented into multiple independent articulated components (legs, pivots, coupling elements) rather than a single rigid structure. This segmentation allows each component to independently adjust to local misalignments while contributing to the overall stable movement of the blade through coordinated action of all segments.
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 significantly reduces fretting and internal tensions, allowing for greater translatability and compensation of thermal changes, thereby enhancing the durability and reliability of switch point systems.
Implementation Method 1
The sliding in the seat guarantees a certain tolerance to the length variations of the blade by means of the thermal excursions
Implementation Method 2
The seat (15) is further open on one part in such a way as to allow the fall outside of eventual external residues and/or fretting residues interposed in the connection
Implementation Method 3
The end (13) further presents a surface (17, 17') of contact with the sliding seat (15) which has a circular shape according to a section plane coinciding with the medium plane passing longitudinally along the length of the manoeuvre hook (10) and further a curve that develops in the direction of the longitudinal axis (300) of the end (13)
Data Source
Figure 1A~2A
Figure 1~2
Figure 3A
AI summary
The present invention concerns an assembly (1) of control and manoeuvre for moving and controlling the blades of a switch point. It comprises a group of manoeuvre (3) coupled with a group of control. The group of manoeuvre (3) comprises a coupling element (11) connected to a manoeuvre hook (10) through a seat (15) obtained at an end (14) of the coupling element (11) and into which an end (13) of the manoeuvre hook (10) engages slidingly and rotatably, the end (15) being open on one side in such a way as to allow the fall outside of eventual external residues and/or residues of fretting interposed in the connection and wherein the end (13) further presents, a surface (17) of contact with the sliding seat (15) which is substantially spherical.