Vehicle Hood Latch Single-Stage Release Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current vehicle hood latch mechanisms require two separate operations to fully release the hood, which can be inconvenient and do not accommodate the increased lift needed for active pedestrian protection systems, and lack a mechanism to absorb striker overtravel during closing.
Innovation Solution
A vehicle hood latch system with a ratchet, pawl, double pull lever, and safety catch levers that allow for a single actuation from inside the vehicle to achieve multiple stages of release, providing visual confirmation of hood opening and absorbing striker overtravel through a biasing mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional two-stage manual release configuration is used, then the hood can be released completely, but the operation becomes inconvenient requiring the occupant to exit the vehicle and perform two different operations
Solution Approach 1:
The patent combines the safety catch lever and double pull lever into a single integrated mechanism. The safety catch lever is operably coupled to the double pull lever such that a single actuation of the double pull lever simultaneously releases both the primary latch and the safety catch, eliminating the need for separate operations and the requirement for the occupant to exit the vehicle.
Solution Approach 2:
The double pull lever serves multiple functions: it acts as both the primary release mechanism and the actuator for the safety catch lever. This multi-functional design allows a single component to perform what traditionally required two separate mechanisms, simplifying the overall system while maintaining safety features.
2Length of moving object
If normal opening lift mechanism is used, then the latch provides standard operation, but the lift height is insufficient for active pedestrian protection systems
Solution Approach 1:
The patent incorporates a biasing mechanism that provides dynamic force to the striker during hood opening. This biasing mechanism works in conjunction with the release mechanism to provide the additional lift height required for active pedestrian protection, allowing the hood to achieve greater opening distance than traditional static latch mechanisms.
3Ease of operation
If the latch mechanism is simplified for single-stage operation, then ease of operation improves, but the ability to accommodate positioning tolerances and absorb striker overtravel may be compromised
Solution Approach 1:
The patent employs a nested arrangement where the safety catch lever is integrated within the overall latch assembly, and the double pull lever is operably coupled to multiple components including the pawl and ratchet. This nested design allows the single-stage operation to reliably accommodate positioning tolerances and absorb striker overtravel while maintaining the simplified operation.
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 convenient, single-stage operation from inside the vehicle for hood release, enhanced safety through visual signaling, and effective absorption of striker overtravel during impact scenarios, improving pedestrian protection.
Implementation Method 1
a pawl mounted on the housing for pivoting about a second pivot axis and biased into engagement with the ratchet
Implementation Method 2
a mechanism to absorb striker over travel in closing direction while providing for normal closing operation, such as during impact situations
Data Source
AI summary
A vehicle hood latch and method of unlatching a vehicle hood is provided. The vehicle hood latch includes a housing; a ratchet pivotally mounted on the housing; a pawl pivotally mounted on the housing and biased into engagement with the ratchet; a pin fixed for conjoint movement with the pawl; a double pull lever operably mounted to the housing and having an abutment surface configured for operable engagement with the pin, and a primary safety catch lever operably mounted to the housing. The primary safety catch lever is configured to pivot from a locked first position to an unlocked second position. The primary safety catch lever moves from the first locked position to the second unlocked position in response to translational movement of the double pull lever caused by engagement of the pin with the abutment surface of the double pull lever.