Rail Noise Insulation Fastener Tool-Free Snap-Fit Design
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Solution Overview
Problem
Existing noise insulation devices for rails require tools for bolt or screw fixation, leading to poor workability and interference with rail maintenance due to overhanging fastening portions.
Innovation Solution
A noise insulation device using a fastener formed of two interlocking fastening members with horizontal and rising portions, eliminating the need for tools and reducing the overhanging portion by fitting together in a re-attachable manner, allowing for secure fastening without bolts or screws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bolt fixation is used to fasten noise insulation members to the rail, then the fastening strength is improved, but a tool is required for installation and the stacked portion overhangs from the rail interfering with maintenance
Solution Approach 1:
The patent replaces the traditional bolt fixation mechanical system with a snap-fit mechanism. The fastening member includes a pressing portion that presses against the noise insulation member and a fitting portion that engages with a groove in the rail, eliminating the need for bolts and tools while maintaining secure fastening through geometric interlocking and elastic deformation of the pressing portion.
Solution Approach 2:
The fastening member is divided into distinct functional portions: a pressing portion for applying force to the noise insulation member, a fitting portion for engaging with the rail groove, and a connecting portion linking them. This segmentation allows each portion to be optimized for its specific function while working together as an integrated fastening system.
2Strength
If screw fixation is used to fasten noise insulation members to the rail, then the fastening strength is improved, but the workability deteriorates due to requiring tools and the process being tedious
Solution Approach 1:
The patent replaces the screw fixation system with a snap-fit mechanism where the fastening member's pressing portion elastically deforms to engage with the noise insulation member and lock in place through the fitting portion's groove engagement. This eliminates screws, nuts, and all associated tools, dramatically simplifying the installation process while maintaining secure fastening.
Solution Approach 2:
The fastening member is designed to self-fasten through its own elastic deformation. The pressing portion naturally applies force to engage with the noise insulation member, and the fitting portion automatically locks into the rail groove through geometric interlocking, requiring no external tools or additional fastening components.
3Strength
If a stacked portion for bolt fixation is provided, then the fastening strength is improved, but the overhanging portion interferes with rail maintenance
Solution Approach 1:
The patent replaces the bolt fixation system that requires an overhanging stacked portion with a snap-fit mechanism where the fastening member integrates smoothly with the rail profile. The fitting portion engages with a groove formed in the rail surface, allowing the fastening member to be flush with or recessed into the rail, eliminating the overhanging portion that interferes with maintenance activities.
Solution Approach 2:
The fitting portion is designed to engage with a groove in the rail through a dimensional relationship that allows the fastening member to sit flush with the rail surface. By utilizing the groove depth and the pressing portion's elastic deformation, the system achieves secure fastening without any portion protruding beyond the rail's outer surface profile.
Data Source
Figure 1
Figure 2~3
Figure 4(a)~4(d)
AI summary
A noise insulation device for a rail provided herein requires no tool for bolt fixation or screw fixation and is therefore capable of making works less tedious and less complex and solves a problem that a portion overhanging from the rail interferes with rail maintenance by reducing the overhanging portion. A noise insulation device 1 for a rail includes a first noise insulation member 2, a second noise insulation member 3, and a fastener 7. The fastener 7 is formed of a first fastening member 8 and a second fastening member 9. The first fastening member 8 has a horizontal portion 41 inserted under a lower surface of a rail bottom and a rising portion 42 provided so as to continue from an end of the horizontal portion 41 and fit to a sound insulation cover 13 of the first noise insulation member 2. The second fastening member 9 has a horizontal portion 51 inserted under the lower surface of the rail bottom and a rising portion 52 provided so as to continue from an end of the horizontal portion 51 and fit to a sound insulation cover 16 of the second noise insulation member. The first fastening member 8 and the second fastening member 9 are fit together in a re-attachable manner.