Tow Hook Assembly Crush Box Collision Force Management

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Solution Overview

Problem

Conventional tow hooks often damage vehicle components during front or side collisions due to their attachment points, leading to potential injury and structural damage.

Innovation Solution

The design of a tow hook assembly featuring a crush box with a support section and a connector section, along with a tow hook body and attachment member, positioned to absorb and distribute collision forces, reducing damage by allowing the tow hook to deform and extend vertically during a collision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the tow hook is fixed to the vehicle at connection points to remain attached during towing, then the tow hook can perform its towing function, but the tow hook may damage vehicle parts during front end or side collision

Engineering Contradiction:

Improvetow hook attachment reliabilityVSAvoiddamage to vehicle parts during collision

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The tow hook assembly is divided into a fixed mounting structure (crush box attached to vehicle frame) and a movable tow hook component. The tow hook can pivot and deform independently from the vehicle frame, allowing it to absorb collision forces without transmitting them to vulnerable vehicle parts.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The design allows the tow hook to deform and pivot during collision, converting the harmful impact force into beneficial deformation work. The crush box and tow hook body are designed to deform in a controlled manner, absorbing collision energy and redirecting forces away from vulnerable vehicle components.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Strength

If the tow hook is made rigid to maintain structural integrity during towing, then the tow hook can withstand towing forces, but the tow hook cannot deform to reduce impact during collision

Engineering Contradiction:

Improvetow hook structural strengthVSAvoidimpact force during collision

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The tow hook is designed with dynamic characteristics, allowing it to pivot and deform during collision while maintaining structural integrity during normal towing. The connection between the tow hook body and crush box enables controlled movement, transforming the rigid structure into a semi-rigid system that can adapt to impact forces.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The effective stiffness of the tow hook assembly changes based on operating conditions. During normal towing, the structure remains rigid for strength. During collision, the tow hook can pivot and deform, effectively reducing its stiffness to absorb impact energy and reduce transmitted forces.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If the tow hook is positioned to extend forward for towing functionality, then the tow hook can engage with towing equipment, but the tow hook directly transmits collision force to vehicle components

Engineering Contradiction:

Improvetow hook engagement capabilityVSAvoidforce transmission to vehicle components

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The crush box acts as an intermediary between the vehicle frame and the tow hook body. It provides a mounting structure that allows the tow hook to extend forward for towing while decoupling the direct force transmission path to the vehicle frame during collision.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This configuration minimizes damage to vehicle components and reduces the risk of injury by absorbing collision forces, allowing the tow hook to deform and extend vertically, thereby reducing the impact on other parts of the vehicle and external barriers.

Implementation Method 1

allowing the tow hook to deform and extend vertically during a collision

Methodology Applied

Scientific EffectDeformation: Deformation

Implementation Method 2

absorb collision forces, allowing the tow hook to deform

Methodology Applied

Scientific EffectEnergy absorption: Absorption (physical)

Data Source

PatentUS20240227475A9Tow hook assemblies and vehicles including same

Publication Date: 2024.07.11 TOYOTA JIDOSHA KK

AI summary

A tow hook assembly including a crush box and a tow hook. The crush box includes a support section having a first end and an opposite second end, the tubular support section extending in a vehicle longitudinal direction, and a connector section provided at the first end of the tubular support section, the connector section including a face plate extending in a vehicle vertical direction perpendicular to the vehicle longitudinal direction, and an upper plate extending from an upper end of the face plate in the vehicle longitudinal direction. The tow hook includes a body having a first portion provided on an upper surface of the upper plate and extending parallel to the upper plate, and an attachment member extending at an oblique angle from the first portion.