Rail Fastening Base Plate With Replaceable Top-Access Dowel
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Solution Overview
Problem
Existing rail fastening systems for ballastless tracks face issues with dowels becoming loose due to buoyancy forces during concrete pouring, making maintenance and replacement difficult and costly, as dowels are locked in place from below and deep within the concrete.
Innovation Solution
A rail fastening system featuring a base plate with through-holes for dowel insertion from above, secured by a retaining contour, allowing for easy removal and replacement of dowels without damaging the concrete, using a threaded connection to ensure secure locking and prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the dowel is locked into the base plate from below and cast deep into the concrete, then the anchoring strength is improved, but the maintainability deteriorates as the base plate must be broken out of the concrete for any dowel removal
Solution Approach 1:
The invention divides the fastening system into separable components: the base plate remains anchored in the concrete while the dowel can be independently removed and replaced. The through-opening in the base plate allows the dowel to be accessed from above, enabling maintenance without destroying the concrete bed or the anchored base plate.
Solution Approach 2:
The dowel is extracted from the base plate structure as a separate, removable component. The through-opening allows the dowel to be taken out from the top side, separating the maintenance operation from the anchored base plate and concrete bed, thus enabling easy replacement without breaking out the concrete.
2Ease of manufacture
If the dowel is held by a spring-loaded retaining means introduced from the bearing surface, then the pre-mounting is secured, but the risk of dowel loosening due to buoyancy forces during concrete pouring increases
Solution Approach 1:
Instead of introducing the dowel from the bearing surface (bottom) as in prior art, the invention introduces the dowel from the opposite side - through the opening accessible from the top. This inversion allows the dowel to be secured against loosening during concrete pouring while maintaining pre-mounting capability.
Solution Approach 2:
The retaining contour is designed to preemptively counteract the buoyancy forces that will act on the dowel during concrete pouring. By providing a mechanical stop that prevents upward movement before the pouring occurs, the system anticipates and prevents the loosening problem.
3Ease of repair
If the opening is a through-hole in the thickness direction, then the dowel can be easily removed and replaced from above, but the structural integrity of the base plate may be compromised
Solution Approach 1:
The base plate is designed with a through-opening that segments the plate into two surfaces (mounting surface and bearing surface) while maintaining overall structural integrity. The opening is sized and positioned to allow dowel access without compromising the load-bearing capacity of the base plate.
Solution Approach 2:
The base plate has different properties in different locations: the opening provides local accessibility for dowel removal, while the surrounding material maintains structural integrity. The mounting surface and bearing surface retain their respective functions despite the presence of the through-opening.
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 system enhances reliability, maintainability, and durability by preventing dowel loosening during concrete pouring and allowing for tool-assisted removal without damaging the rail subsurface, reducing maintenance costs and structural damage.
Implementation Method 1
The dowel is introduced into the opening, is held in place by a retaining contour and projects in the thickness direction at least on one side beyond the base plate
Implementation Method 2
using a threaded connection to ensure secure locking
Implementation Method 3
During pouring, the concrete generates a buoyancy force which acts from below on the base plate and pushes it upwards. At the same time, the dowels are held in place by the concrete
Data Source
AI summary
Rail fastening system (1) for fastening a rail (2) to a rail subsurface, preferably for a ballastless track, comprising a base plate (10), preferably made of a plastic, and at least one dowel (20), wherein the base plate (10) has at least one opening (15), which completely penetrates the base plate (10) in the thickness direction, and the dowel (20) is introduced into the opening (15), is held therein by means of a retaining contour and projects in the thickness direction at least on one side beyond the base plate (10).