Rear Impact Guard with Segmented Posts for Off-Center Crash Protection
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Solution Overview
Problem
Conventional rear impact guards for over-the-road trailers are inadequate in protecting against off-center impacts, particularly due to their design and weight constraints, which limits their effectiveness in minimizing crash severity while maintaining cost efficiency.
Innovation Solution
The design incorporates a rear impact guard with a bumper positioned below the rear bolster, featuring a pair of outboard posts and an inboard post, secured to the trailer frame with fasteners, along with lateral reinforcement members and corner gussets to enhance structural integrity and distribute impact loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rear impact guard design is used, then cost is reduced, but protection against off-center impacts is insufficient
Solution Approach 1:
The rear impact guard is divided into multiple independent posts (outboard posts and inboard posts) that are spaced apart laterally. Each post is independently secured to the trailer frame at multiple locations, allowing the structure to handle off-center impacts more effectively while maintaining modular simplicity for cost-effective manufacturing and installation.
Solution Approach 2:
The impact guard structure provides different levels of reinforcement at different lateral positions. The outboard posts are positioned at the extreme lateral edges to handle off-center impacts, while inboard posts provide additional support closer to the center. This localized reinforcement approach improves off-center impact protection without requiring uniform complexity throughout the entire structure.
2Strength
If additional reinforcement members are added, then structural integrity is improved, but weight increases
Solution Approach 1:
The lateral reinforcement members are pre-configured to extend from the trailer frame in specific geometric patterns that optimize strength-to-weight ratio. The members are positioned to leverage the existing trailer frame structure, providing maximum reinforcement with minimum additional material. The fastening system is designed to secure members at predetermined locations that maximize structural efficiency.
Solution Approach 2:
The reinforcement structure combines different material properties and configurations - the lateral reinforcement members work in conjunction with the vertical posts and the existing trailer frame to create a composite structural system. This composite approach distributes loads efficiently across multiple components, achieving high structural integrity without requiring any single component to be excessively heavy.
3Reliability
If multiple fastening points are used, then securement is improved, but installation time increases
Solution Approach 1:
The fastening system is segmented into multiple independent fastening points distributed along the length of each reinforcement member. Each fastening point can be installed independently, allowing for modular installation. The segmented approach provides multiple securement points for reliability while enabling parallel installation processes that reduce total installation time compared to a single complex fastening operation.
Solution Approach 2:
The reinforcement members are designed with self-aligning features and pre-drilled fastening holes that facilitate straightforward installation. The geometric configuration of the members allows them to self-position relative to the trailer frame, reducing the need for complex alignment procedures. This self-service design maintains high securement reliability through multiple fastening points while minimizing installation time through simplified installation procedures.
Data Source
AI summary
A trailer includes front and rear ends spaced in a longitudinal direction to define a cargo area. A frame includes a rear bolster extending in a transverse direction across the rear end below a bottom rear edge of the cargo area. Spaced rear frame posts extend upwardly from respective distal ends of the rear bolster. A rear impact guard includes a bumper extending transversely and spaced below the rear bolster, a pair of outboard posts extending between the bumper and the rear bolster adjacent the respective distal ends of the rear bolster, and at least one inboard post. Each of the outboard posts has a rearward-extending horizontal first flange and an upward-extending vertical second flange spaced forwardly of the first flange, these flanges including multiple apertures aligned with apertures in the trailer frame, each of the apertures accommodating a removable fastener securing the rear impact guard to the trailer frame.