Helmet Swinging Insert Liner for Rotational and Translational Acceleration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional helmets fail to effectively reduce rotational acceleration and translational acceleration, particularly when impacts occur above the helmet's center of gravity, leading to diffuse axonal injuries due to shearing of brain axons.
Innovation Solution
A helmet design featuring a shock absorbing liner with a recessed portion for an insert liner, which includes a central support member and three peripheral support members, allowing the insert liner to tilt and swing, reducing rotational and translational accelerations through deformation and movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the outer shell and shock absorbing liner is increased to reduce maximum acceleration, then the protection performance is improved, but the rigidity of the top portion becomes excessively high making it difficult to absorb impact
Solution Approach 1:
The patent applies local quality by providing a recessed portion specifically in the top portion of the shock absorbing liner, while maintaining the overall thickness of the liner. This localized modification reduces the rigidity only where needed (top portion) without compromising the overall protection performance provided by the full-thickness liner in other regions.
Solution Approach 2:
The shock absorbing liner is segmented into two functional regions: the main body with full thickness for overall impact absorption, and the recessed portion with reduced thickness for reducing top portion rigidity. This segmentation allows different regions to serve different protective functions simultaneously.
2Reliability
If conventional insert liner structures are used to reduce top portion rigidity, then the translational acceleration is reduced, but the rotational acceleration propagates to the wearer's head causing diffuse axonal injury
Solution Approach 1:
The patent makes the insert liner dynamic by allowing it to swing freely within the recessed portion rather than fixing it rigidly. This dynamic capability enables the insert liner to move and tilt in response to rotational impacts, thereby absorbing rotational energy and preventing its propagation to the wearer's head.
Solution Approach 2:
The recessed portion is pre-configured to accommodate the insert liner's swinging motion. This preliminary structural arrangement ensures that when rotational impact occurs, the insert liner can immediately begin its swinging motion to mitigate rotational acceleration without requiring additional adaptive mechanisms.
3Reliability
If the insert liner is made with smaller density to reduce top portion rigidity, then the impact absorbability is maintained, but the volume of the insert liner must be increased which affects helmet size
Solution Approach 1:
Instead of reducing the density of the entire insert liner, the patent maintains the liner's density and instead creates a localized recessed portion with reduced thickness. This approach achieves the same rigidity reduction effect without increasing the overall volume of the insert liner material.
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 design effectively reduces both rotational and translational accelerations, enhancing safety by minimizing shearing forces on the brain, while maintaining comfort and stability.
Implementation Method 1
the shock absorbing liner functions to absorb, through a reduction in its thickness (i.e., compression), the impact energy propagated from the outer shell
Implementation Method 2
the insert liner tilts. That is, the insert liner moves with respect to the main body liner. At this time, the wearer's head in close contact with the insert liner also moves together with the insert liner, so rotational acceleration does not propagate to the inside of the head
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A helmet that can effectively reduce the rotational acceleration of an impact and at the same time also effectively reduce translational acceleration is provided. A helmet has an outer shell comprising a hard material and a shock absorbing liner (14) disposed inside the shell. The shock absorbing liner (14) comprises a main body liner (16), a recessed portion (30) provided at an inner surface of the main body liner (16), an insert liner (18) fitted into the recessed portion (30), and a central raised portion (42) (central support member) disposed between a bottom surface of the recessed portion (30) and a bottom surface of the insert liner (18). When the helmet receives an impact, the insert liner (18) swings about the central support member as a fulcrum, thereby reducing the impact.