Direct Fixation Fastener With Interlocking Eccentrics
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Solution Overview
Problem
Existing rail fastening systems face challenges with variability in substrate construction and attachment mechanisms that can shift or deform over time, leading to misalignment and vibration issues.
Innovation Solution
A direct fixation fastener with lateral positioners featuring eccentrics that interlock with a frame, allowing for angular adjustments and secure clamping to a substrate without direct contact, using an overmolded jacket for vibration attenuation and electrical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional direct fixation fasteners are used with fixed positioners, then the fastening structure is simple, but the fastener cannot accommodate substrate variations and attachment mechanism migration over time
Solution Approach 1:
The positioner is made adjustable through the eccentric mechanism, transforming a static fastening system into a dynamic one that can adapt to substrate variations and attachment mechanism migration over time
Solution Approach 2:
The eccentric mechanism is nested within the positioner bore, with the eccentric body containing an offset bore that receives the attachment mechanism, allowing compact integration of adjustment functionality within the existing fastener structure
2Adaptability or versatility
If adjustable positioners are added to accommodate substrate variations, then adaptability improves, but the device complexity increases
Solution Approach 1:
The eccentric mechanism utilizes asymmetric geometry where the offset bore is deliberately positioned away from the center of the eccentric body, enabling lateral adjustment through rotation while maintaining a relatively simple overall structure
Solution Approach 2:
The eccentric mechanism serves multiple functions: it provides lateral adjustment capability, maintains secure engagement through interlocking teeth and slots, and accommodates various attachment mechanism positions, reducing the need for additional specialized components
3Manufacturing precision
If eccentrics with interlocking teeth and slots are used for lateral adjustment, then adjustment precision and stability improve, but manufacturing complexity increases
Solution Approach 1:
The asymmetric offset bore design allows precise lateral positioning to be achieved through simple rotational adjustment of the eccentric body, where the offset distance directly determines the adjustment range without requiring complex machining operations
Solution Approach 2:
The interlocking teeth and slots divide the adjustment mechanism into discrete engagement points along the slot length, allowing precise positioning at multiple discrete locations while maintaining a relatively simple continuous slot geometry that is easy to manufacture
Data Source
AI summary
A direct fixation track rail fastener includes a fastener body having a top plate, a frame, and an overmolded jacket. A first and a second lateral positioner are positioned in positioner bores extending through the fastener body, and each includes an eccentric. The eccentrics include axially extending external teeth interlocked with axially extending slots within the positioner bores. In an aspect, the eccentrics are dual eccentrics each including tooth and slot interlocking arrangements with another eccentric or the frame.