Vehicle Hood Double-Pull Lock With Backup Safety Catch

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Solution Overview

Problem

Existing double-pull locks for vehicle hoods are prone to damage due to repeated actuation of the pawl, leading to potential unintentional unlocking, especially when the vehicle is in motion, as the spring of the pawl may get damaged or ejected from its seat.

Innovation Solution

A double-pull lock design with a safety catch mechanism where the pawl's spring is not constantly stressed, ensuring the lock remains closed when the spring is not functioning, incorporating a secondary spring system to maintain safety and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pawl is constantly stressed by a spring towards its locking position, then the lock can be reliably locked, but the spring may get damaged or ejected from its seat due to repeated actuation

Engineering Contradiction:

Improvelocking reliabilityVSAvoidspring service life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent introduces a secondary spring system that acts as a backup when the primary spring fails. This beforehand cushioning mechanism ensures that if the primary spring gets damaged or ejected, the secondary spring can still maintain the locking function, preventing complete system failure due to spring deterioration from repeated actuation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent changes the operational state of the pawl by introducing a control mechanism that allows the pawl to be held in the unlocked position without constant spring stress. This parameter change in the pawl's operational state reduces the cumulative stress on the spring, extending its service life while maintaining reliable locking when needed.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If the spring of the pawl is constantly stressed, then the lock can be actuated reliably, but the lock may open unintentionally when the spring is damaged or ejected

Engineering Contradiction:

Improveactuation reliabilityVSAvoidunintentional unlocking prevention

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The secondary spring system serves as a beforehand cushioning mechanism that takes over the function of the primary spring if it fails. This ensures that even if the primary spring is damaged or ejected, the lock cannot open unintentionally because the secondary spring maintains the necessary stress on the pawl to keep it in the locked position.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The secondary spring acts as an intermediary backup mechanism between the primary spring and the pawl. It mediates the force transmission to the pawl, ensuring continuous locking action even when the primary spring fails, thus preventing unintentional unlocking while maintaining actuation reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a safety catch is added to retain the striker in partial closing position, then safety is improved, but the device complexity increases

Engineering Contradiction:

Improvesafety retentionVSAvoidmechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The safety catch mechanism is designed to serve multiple functions: it retains the striker in partial closing position, provides backup locking if the primary spring fails, and maintains safety during normal operation. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while improving safety retention.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the safety retention function with the existing pawl and catch mechanism by integrating the secondary spring system into the same assembly. This merging of functions allows the safety catch to provide backup locking without requiring a completely separate mechanism, thus improving safety while minimizing the increase in device complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 ensures the lock remains securely closed when the primary spring fails, preventing unintentional unlocking, enhancing safety and reliability, and maintaining functionality even when the primary spring is damaged or ejected.

Implementation Method 1

the pawl of a double-pull lock is constantly stressed by a spring towards its locking position of the catch

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 2

incorporating a secondary spring system to maintain safety and reliability

Methodology Applied

Scientific EffectSpring: Spring

Data Source

PatentUS20260022593A1Double-pull lock with safety catch for a vehicle hood

Publication Date: 2026.01.22 CEBI ITALY SPA

AI summary

A lock for a vehicle hood includes a catch, a pawl and a safety catch hinged in a box. The safety catch has an actuation arm that abuts against an actuation pin of the pawl. A first spring pushes the pawl and a second spring pushes the safety catch. The second resultant force exerted by the second spring on the actuation arm of the safety catch is lower than the first resultant force exerted by the first spring on the actuation pin of the pawl.