Vehicle Hood Latch with Double Pull Lever Actuation
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Solution Overview
Problem
Current vehicle hood latches require cumbersome and inconvenient operations for occupants to open, especially in situations requiring increased hood lift for pedestrian safety, as they necessitate manual actuation from both inside and outside the vehicle, and struggle with accommodating manufacturing tolerances.
Innovation Solution
A latch system with a housing, ratchet, pawl, and safety catch member that allows for double pull lever actuation from inside the vehicle to unlock the latch, incorporating linkages for automated and manual operation, and a blocking member to manage ratchet movement, enabling enhanced hood opening and safety catch engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional hood latch with safety catch lever is used, then the latch provides secure locking, but the occupant must perform two separate operations (internal handle pull and external safety catch release) to open the hood
Solution Approach 1:
The patent combines the safety catch lever and latch lever into a single integrated component. The safety catch lever is positioned such that when the occupant pulls the internal handle, the cable simultaneously actuates both the latch release and the safety catch lever, eliminating the need for a separate external manual release operation.
Solution Approach 2:
The integrated safety catch lever serves multiple functions: it acts as both the safety catch mechanism and the latch release lever. This multi-functional design allows a single component to perform what previously required two separate mechanisms, simplifying the overall operation while maintaining security.
2Ease of operation
If the safety catch lever is positioned on the front of the vehicle, then it is easily accessible from outside, but it requires manual direct actuation by reaching under the hood which is cumbersome
Solution Approach 1:
The internal handle pull mechanism is designed to automatically position and actuate the safety catch lever before the hood can be opened. By the time the occupant needs to open the hood, the safety catch lever has already been moved to the correct position and engaged, eliminating the need for the occupant to manually locate and actuate it.
Solution Approach 2:
The latch system is designed to automatically manage the safety catch lever through the cable linkage connected to the internal handle. When the occupant pulls the handle, the system self-actuates the safety catch lever without requiring any additional manual intervention, making the system serve itself.
3Length of moving object
If the latch requires two-stage actuation for normal operation, then it provides secure locking, but it cannot provide sufficient hood lift travel for active pedestrian protection systems
Solution Approach 1:
The patent incorporates a dynamic blocking member that can pivot between different positions. During normal operation, the blocking member restricts ratchet movement to provide secure locking. During pedestrian protection events, the increased force causes the blocking member to pivot, allowing the ratchet to travel further and enabling greater hood lift.
Solution Approach 2:
The latch mechanism allows the ratchet travel parameter to change based on the blocking member's position. Under normal conditions, the blocking member limits ratchet rotation to a small angle. Under pedestrian protection conditions, the blocking member pivots to allow significantly greater ratchet rotation, thereby increasing hood lift travel.
Data Source
AI summary
A latch for a vehicle hood and method of construction thereof is provided. The latch includes a housing; a ratchet pivotally mounted on the housing and a pawl pivotally mounted on the housing for pivoting between a first position in locked engagement with the ratchet and a second position out of locked engagement with the ratchet, with the pawl being biased into the first position. A pawl lever is pivotally mounted on the housing to engage the pawl and rotate the pawl from the first position to the second position. A double pull lever having an abutment surface is pivotally mounted on the pawl lever. A safety catch member is pivotally mounted on the housing, wherein the safety catch member selectively engages the abutment surface of the double pull lever to pivot the safety catch member from a locked first position to an unlocked second position.