Steering Column Lever Breakaway Design
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Solution Overview
Problem
The existing steering column assembly levers are not designed to prevent injury to the driver in the event of a collision, as they can be impacted by the driver's legs and may cause harm due to their rigid structure and location.
Innovation Solution
A locking lever with a breakaway design featuring a connecting portion of reduced shear strength and a flexible tether that allows the lever to break away from the main body during impact, preventing the broken part from causing further injury by remaining attached through the tether.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lever is made rigid and positioned for convenient driver operation, then the lever provides a high quality feel and robust performance, but it creates a safety hazard by potentially injuring the driver during a collision
Solution Approach 1:
The lever is divided into a first portion (root part) and a second portion (end part with handle) connected by a connecting portion. The connecting portion has reduced shear strength compared to the adjacent portions, creating a designed breakaway point. This segmentation allows the lever to maintain rigidity during normal operation while enabling controlled fracture during impact to reduce injury risk.
Solution Approach 2:
The connecting portion is designed with different mechanical properties (lower shear strength) compared to the rest of the lever. This parameter change creates a weak link that preferentially fails under high impact loads while maintaining overall lever functionality during normal use. The tether attached to the broken end portion further modifies the system's mechanical behavior post-failure.
2Strength
If the lever is designed as a single rigid component, then it provides structural integrity and durability, but it becomes a projectile hazard during collision that can cause secondary injury
Solution Approach 1:
The lever is divided into a first portion (root part) and a second portion (end part with handle) connected by a connecting portion. The connecting portion has reduced shear strength compared to the adjacent portions, creating a designed breakaway point. This segmentation allows the lever to maintain rigidity during normal operation while enabling controlled fracture during impact to reduce injury risk.
Solution Approach 2:
A flexible tether is attached to the second portion of the lever to prevent it from becoming a free-flying projectile after breakaway. The tether acts as an intermediary that restrains the broken end portion, allowing it to move but preventing uncontrolled movement that could cause secondary injury to occupants.
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 breakaway design reduces the risk of driver injury during collisions by allowing the lever to detach safely and preventing the broken part from becoming a projectile within the vehicle, thus minimizing secondary injury risks.
Implementation Method 1
a connecting portion or region between the first portion and the second portion about which the second portion may preferentially breakaway from the first portion
Implementation Method 2
a flexible tether that prevents the second portion fully separating from the first portion after the lever has broken about the connection portion or region
Data Source
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AI summary
A locking lever for a clamp mechanism of a steering column assembly comprises a first portion, a second portion that extends from the first portion, and a connecting portion or region located between the first portion to the second portion about which the second portion will preferentially breakaway from the first portion in the event of an impact by an occupant of the vehicle on the second part, the lever further comprising a flexible tether that prevents the second portion fully separating from the first portion after the lever has broken about the connection portion or region.