Collapsible Tow Bar Assembly for Pedestrian Safety
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Solution Overview
Problem
Existing fixed tow bar assemblies for vehicles are non-deformable, posing challenges in compliance with modern pedestrian safety regulations during collisions, as they do not meet the geometric and deformable requirements of modern bumpers.
Innovation Solution
A tow bar assembly with a collapsible connecting device that includes a cylindrical spacer sleeve and an elastic locking split pin, allowing the tow hook to retract when a thrust action exceeds a predefined value, ensuring compliance with pedestrian safety regulations by severing when excessive force is applied, thus enabling the hook to detach from the load-bearing structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixed tow bar assembly is used, then the towing stability is maintained, but the pedestrian safety compliance deteriorates due to non-deformability during collision
Solution Approach 1:
The tow bar assembly transitions from a static fixed connection to a dynamic collapsible connection. The connecting device includes a collapsible section that can deform rearward upon forward impact, transforming the rigid structure into a dynamic one that adapts its rigidity based on the applied force direction and magnitude.
Solution Approach 2:
The connecting device changes its structural parameters under load. When a thrust action exceeding a predefined value is applied, the collapsible section deforms, changing the geometric and mechanical properties of the tow bar assembly to comply with pedestrian safety regulations while maintaining towing stability under normal conditions.
2Object-affected harmful factors
If a collapsible connecting device is used, then the pedestrian safety compliance is improved, but the towing stability deteriorates due to potential detachment under excessive force
Solution Approach 1:
The connecting device is divided into distinct functional sections: a permanent attachment device for secure mounting and a collapsible section for energy absorption. This segmentation allows the permanent attachment to maintain towing stability while the collapsible section provides safety compliance during collisions.
Solution Approach 2:
The collapsible section is designed to remain rigid under normal towing forces to maintain stability, but dynamically collapses when subjected to excessive thrust forces during pedestrian collisions, thus providing conditional stability that satisfies both towing and safety requirements.
3Ease of manufacture
If the elastic locking split pin is used, then the detachment mechanism is simplified, but the manufacturing precision deteriorates due to the need for precise fit between the pin and through hole
Solution Approach 1:
The elastic locking split pin is designed as a simple, inexpensive component that can be easily manufactured and replaced. Its simplicity in design and manufacturing is prioritized, accepting that precise fit is achieved through standard elastic locking mechanisms rather than high-precision custom fittings.
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 tow bar assembly provides stability during towing while ensuring compliance with pedestrian safety regulations by allowing the tow hook to retract under excessive force, preventing damage to pedestrians in collisions and maintaining structural integrity.
Implementation Method 1
an elastic locking split pin, which has a shaped arm straddling the sleeve and a straight arm inserted into a hole through the sleeve coaxially to the hole through the wall
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A tow bar assembly (5) is coupled to a load-bearing structure (3) of a vehicle (1), the assembly having a coupling end portion (8) of a device for towing the vehicle and a connecting device (13) for connecting the coupling end portion (8) to the load-bearing structure (3); the connecting device (13) having two attachment assemblies (33) (34) arranged on opposite sides of a pillar wall (3A) of the load-bearing structure (3) to attach the coupling end portion (8) to the load-bearing structure (3) when the vehicle (1) is towed and a collapsible attachment device (15) configured to enable the coupling end portion (8) to retract in relation to the load-bearing structure (3) when a thrust action, opposing the towing action and of a lower intensity than the towing action, is exerted on the coupling end portion (8).