Breakaway Tow Hook Assembly for Vehicle Safety
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Solution Overview
Problem
Rigidly mounted tow hooks on motor vehicles pose challenges in designing supplemental restraint systems, as they can activate airbags during low-speed impacts, requiring adjustments to ensure proper airbag deployment characteristics without interfering with towing functions.
Innovation Solution
A tow hook assembly with a mount bracket, support bracket, and fastener that allows the tow hook to break away from the vehicle upon a force less than that required to activate airbags, featuring a design where the tow hook moves opposite to the towing direction and is retained within the mount bracket, with a tab that deforms to facilitate this movement once a predetermined force is exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tow hook is rigidly mounted to the front bumper, then the towing function is ensured, but the airbag may be activated during low-speed impacts
Solution Approach 1:
The tow hook assembly is divided into separable components: the tow hook itself and the mount bracket attached to the vehicle. The mounting end of the tow hook can detach from the mount bracket during low-speed impacts, while remaining secure during normal towing operations. This segmentation allows the system to provide towing functionality when needed while preventing harmful airbag activation during minor collisions.
2Object-affected harmful factors
If the tow hook is made breakaway to prevent airbag activation, then airbag system operation is improved, but the towing function may be compromised
Solution Approach 1:
The mounting system transitions from a static rigid connection to a dynamic conditional connection. The tow hook remains firmly attached to the mount bracket during normal towing forces, but automatically detaches when impact forces exceed a predetermined threshold. This dynamic behavior ensures towing reliability under appropriate conditions while preventing airbag activation during excessive forces.
Solution Approach 2:
The system changes its mechanical connection parameter based on applied force magnitude. Under normal towing loads, the connection maintains full strength; under impact loads exceeding the threshold, the connection parameter changes to allow detachment. This parameter change enables the system to differentiate between legitimate towing forces and harmful impact forces.
3Ease of operation
If the tow hook protrudes from the bumper face, then towing accessibility is improved, but it becomes the initial contact point during impact
Solution Approach 1:
The mount bracket serves as an intermediary element between the vehicle structure and the tow hook. It provides a mounting platform that positions the tow hook for accessibility while incorporating force-absorbing characteristics. The bracket acts as a buffer that can deform or detach under impact, preventing direct force transmission to the airbag system while maintaining towing functionality.
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
Enables the tow hook to perform its towing function without affecting airbag deployment, ensuring the airbag system activates only during significant impacts, maintaining vehicle safety and operational integrity.
Implementation Method 1
the tab is positioned and dimensioned so as to be in front of the support bracket, and is engineered so that the tow hook will remain substantially in place until a force in a direction opposite to the towing direction exceeds a predetermined value that is less than the force required to deploy the vehicle air bags. Once the force exceeds this value, the tow hook moves in the direction opposite the towing direction and at least one of the tab and the support bracket is deformed so as to allow movement of the tow hook
Data Source
AI summary
A tow hook assembly that includes a mount bracket, a tow hook having a towing end and a mounting end extending axially along a towing direction and through the mount bracket, a support bracket positioned proximal to the towing end of the tow hook and configured to support the towing end of the tow hook, and a fastener attached to the mounting end of the tow hook. The tow hook assembly is attached between the frame rail and impact beam of a motor vehicle such that the motor vehicle may be towed by the tow hook assembly and such that the tow hook assembly will break away from the motor vehicle upon application of a force which is less than a force required to activate an airbag.