Vehicle Tailgate Lock Spring Support for Snow Load

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Solution Overview

Problem

Existing vehicle tailgate locks can be hindered by external loads like snow, causing the torsion spring's insufficient force to open the rotary latch, leading to premature pawl closure and repeated unlocking processes.

Innovation Solution

A lock design where the leg spring's first leg forms a support section that engages with a counter bearing on the pawl or actuating lever, keeping the pawl raised until the rotary latch reaches its open position, allowing the torsion spring to perform a dual function of opening the latch and holding the pawl in the raised position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pawl is held raised using a separate mechanism, then the snow load function is achieved, but the device complexity increases

Engineering Contradiction:
Improvesnow load functionVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the snow load holding function into the existing leg spring by forming a support section on one of its legs. This support section engages with a counter-bearing on the pawl or actuating lever to maintain the pawl in the raised position during snow load conditions, eliminating the need for a separate holding mechanism and reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The leg spring is designed to perform multiple functions: it provides the restoring force for the rotary latch, and through its support section, it also holds the pawl in the raised position during snow load conditions. This multi-functionality reduces the total number of components needed in the lock mechanism.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If the torsion spring force is increased to open the rotary latch under snow load, then the opening reliability improves, but the device complexity and manufacturing costs increase

Engineering Contradiction:
Improvelatch opening under loadVSAvoidmanufacturing costs
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The support section acting as an intermediary mechanical element engages with the counter-bearing to provide a mechanical holding function. This allows the existing torsion spring to maintain its original force characteristics while the support section mechanism ensures the pawl remains raised during snow load conditions, avoiding the need to increase spring force.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the pawl closes prematurely, then the locking function is restored, but the lock cannot be opened under snow load

Engineering Contradiction:
Improvelock openingVSAvoidpawl position stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The support section is designed to engage with the counter-bearing before the rotary latch reaches its fully open position. This preliminary engagement holds the pawl in the raised position in advance, preventing premature closure and ensuring the latch can complete its opening motion even under snow load conditions.

Inventive Principle:
Principle #10Preliminary action

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

This design simplifies the lock's construction, reduces components, enhances reliability, and prevents premature pawl closure, ensuring the lock can be opened even under external loads without repeated unlocking attempts.

Implementation Method 1

a torsion spring, against the restoring force of which the rotary latch can be rotated from its open position into its closed position

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Implementation Method 2

a leg spring (16), in particular a torsion spring, acting on the rotary latch (10) with a spring force

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3604722B1Lock
Publication Date: 2021.01.06 WITTE AUTOMOTIVE GMBH
  • EP3604722B1 patent drawingFigure 1~2
  • EP3604722B1 patent drawingFigure 3~4

AI summary

The invention relates to a lock, in particular for a tailgate of a motor vehicle, comprising a rotary latch rotatable about a pivot axis between an open position and a closed position, a pawl which engages with the rotary latch in its closed position and can be released from it to release the rotary latch, and a torsion spring against whose restoring force the rotary latch can be rotated from its open position to its closed position, wherein a first leg of the torsion spring forms a support section which can be brought into engagement with a counter bearing formed on the pawl or on an actuating lever cooperating with the pawl by releasing the pawl from the rotary latch in order to hold the pawl in a raised position, wherein the engagement between the support section and the counter bearing can be released by rotating the rotary latch from the closed position to the open position.