Thermoplastic Elastomer Hitch Step Impact Absorption
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Solution Overview
Problem
Existing hitch steps, typically made of metal, add significant weight to vehicles and are not effective in absorbing the impact of rear-end collisions due to their limited ability to absorb forces rather than transmit them.
Innovation Solution
A hitch step injection-molded from a thermoplastic polymer compound, specifically a stiff thermoplastic elastomer, which is designed to absorb energy from rear-end collisions while supporting vertical loads without unacceptable deformation, using a structure with thin walls and internal support members to enhance flexibility and impact absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a hitch step is made of metal to withstand vertical loads, then strength and load-bearing capability are improved, but weight increases considerably
Solution Approach 1:
The patent changes the material parameter from metal to thermoplastic polymer, fundamentally altering the weight-to-strength ratio. The polymer material achieves sufficient load-bearing capability while dramatically reducing weight compared to metal construction.
Solution Approach 2:
The patent employs a composite structure combining thermoplastic polymer material with an open-cell foam core. This composite construction provides both the necessary strength for load-bearing and the weight reduction benefits of polymer materials, while the foam core adds energy absorption capabilities.
2Stability of the object's composition
If a hitch step is made of metal to ensure structural rigidity, then deformation resistance is improved, but impact absorption capability deteriorates
Solution Approach 1:
The patent applies different material properties to different regions of the hitch step. The outer shell uses thermoplastic polymer for rigidity and deformation resistance, while the internal foam core provides energy absorption. This local differentiation allows simultaneous achievement of both deformation resistance and impact absorption.
Solution Approach 2:
The foam core is pre-positioned within the polymer structure to provide cushioning before impact occurs. This beforehand cushioning arrangement allows the structure to absorb impact energy through controlled deformation of the foam, protecting the vehicle from rear-end collisions.
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 thermoplastic elastomer hitch step effectively absorbs rear-end collision forces, providing improved safety and reducing vehicle weight by utilizing its elastic properties to absorb impact energy rather than transmitting it to the vehicle.
Implementation Method 1
a relatively stiff thermoplastic elastomer (TPE) that is capable of absorbing energy from a rear-end collision
Implementation Method 2
exhibits excellent elastic memory... capable of absorbing energy from a rear-end collision
Data Source
AI summary
A trailer hitch step, integrally injection-molded of a thermoplastic polymer compound, is capable of accepting a predetermined off-axis vertical load without an objectionable degree of torsional displacement, while capable of absorbing energy from rear impacts.