Double Pull Vehicle Hood Latch with Two-Stage Pawl

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Solution Overview

Problem

Conventional vehicle hood latches require occupants to exit the vehicle and manually actuate a lever under the hood, which is inconvenient and may result in accidental complete opening of the hood.

Innovation Solution

A latch system incorporating a ratchet, pawl, release lever, and optional pawl lockout member, allowing for two-stage operation where the pawl can be driven from a primary locking to a secondary locking position and then to an unlocked position using a single handle actuation, eliminating the need for a separate underhood lever and preventing accidental full opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional two-stage latch system is used with a separate underhood lever, then the hood can be securely locked, but the operation becomes inconvenient requiring occupants to exit the vehicle

Engineering Contradiction:

Improvehood latch operation convenienceVSAvoidlatch system structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines the primary and secondary locking functions into a single integrated latch assembly. The pawl mechanism integrates both locking positions (first and second engagement positions with the ratchet) within one component, eliminating the need for a separate underhood lever and allowing both locking stages to be controlled from the interior handle alone.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single interior handle is designed to perform multiple functions: it can lock the hood in the primary closed position, transition to the secondary closed position, and fully unlock the hood all through one continuous pulling motion. This multi-functional design eliminates the need for separate control mechanisms for each stage.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If a conventional latch system is used, then the structure is simpler, but accidental complete opening of the hood may occur

Engineering Contradiction:

Improveaccidental opening preventionVSAvoidlatch system structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The latch system divides the locking function into two distinct stages: a first closed position with primary security and a second closed position with enhanced security. The ratchet is segmented with two separate engagement surfaces that can be selectively engaged by the pawl, creating progressive locking stages that prevent accidental full opening.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The latch system performs a preliminary locking action at the first closed position before requiring a deliberate second action to reach the second closed position. This staged approach ensures that the hood cannot accidentally transition from primary to fully open, as it requires two distinct intentional operations.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a two-stage locking mechanism is implemented, then accidental opening is prevented, but the operation becomes more complex requiring multiple steps

Engineering Contradiction:

Improveaccidental opening preventionVSAvoidhood latch operation convenience

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The release lever is designed with dynamic, continuous motion capability that allows it to traverse through both locking stages in a single uninterrupted pulling action. The lever's movement dynamically transitions the pawl from the first engagement position to the second engagement position and finally to the unlocked position, maintaining ease of operation despite the two-stage locking mechanism.

Inventive Principle:

Principle #15Dynamics

4Ease of operation

If the release lever has extended reach to operate both stages, then convenience is improved, but the risk of inadvertent full opening increases

Engineering Contradiction:

Improverelease lever accessibilityVSAvoidinadvertent opening prevention

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The latch system incorporates mechanical feedback through the ratchet-pawl engagement that provides tactile and positional confirmation at each stage. The pawl's engagement with the first and second engagement positions creates distinct mechanical states that feedback to the release lever, allowing the system to recognize when each stage is reached and preventing inadvertent progression to full opening.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11933086B2Double pull latch for closure panel such as hood

Publication Date: 2024.03.19 MAGNA CLOSURES INC

AI summary

In an aspect, a latch for a closure panel for a vehicle is provided, and includes a ratchet, pawl, release lever, and extension member. The ratchet is movable between a primary closed position, secondary closed position and open position. The pawl is movable between a primary locking position, secondary locking position and unlocking position. The release lever is movable between home and actuated positions. When the pawl is in the primary locking position the release lever has a selected amount of reach for driving the pawl to the secondary locking position during movement of the release lever to the actuated position. When the pawl is in the secondary locking position the extension member is movable to extend the reach of the release lever to drive the pawl from the secondary locking position to the unlocked position during movement of the release lever from the home position to the actuated position.