Motor Vehicle Door Latch Leg Spring Storage

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Solution Overview

Problem

Motor vehicle door latches with spring-impinged storage elements often require repeated operation to open due to issues like frost, as the pawl may not fully disengage from the catch, leading to incomplete opening of the door or flap, increasing effort and cost.

Innovation Solution

A leg spring storage element is anchored in the latch housing with one leg and maintains the pawl in an elevated position until the catch is fully open, featuring a stop on the other leg that interacts with the pawl to prevent re-engagement into a ratchet position, combining the functions of a spring and storage element into a single component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional storage element is used to maintain the pawl in the storage position, then functional safety is improved, but device complexity and cost increase

Engineering Contradiction:
Improvefunctional safetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the storage element and the spring into a single integrated component called a 'leg spring'. This leg spring has one leg anchored in the latch housing and another leg that acts as the storage element maintaining the pawl in the storage position. By merging these two previously separate components into one, the patent reduces device complexity and construction costs while maintaining the functional safety of keeping the pawl elevated during the opening process.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If the pawl is maintained in the storage position during opening, then reliability is improved, but the structure becomes more complex

Engineering Contradiction:
Improveprevention of incomplete openingVSAvoidstructure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the spring and storage element into a single leg spring component, reducing structural complexity while maintaining the reliability function of preventing incomplete opening. The leg spring's design with one anchored leg and one pawl-maintaining leg achieves the same functional result as separate components would provide, but with fewer parts and simpler construction.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a separate spring and storage element are used, then functional safety is ensured, but manufacturing cost increases

Engineering Contradiction:
Improvefunctional safetyVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent reduces manufacturing cost by consolidating the spring and storage element into a single leg spring component. This integration reduces the number of parts that need to be manufactured, assembled, and quality-checked, thereby lowering production costs while maintaining functional safety through the stop-protrusion mechanism that prevents re-engagement of the pawl with the catch.

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

This design reduces construction and cost while ensuring functional safety by maintaining the pawl in a storage position until the catch is fully open, preventing re-engagement and facilitating complete opening of the door or flap.

Implementation Method 1

a spring-impinged storage element which is designed as a leg spring with one leg 8b anchored in the latch housing and with the other leg 8a maintaining the pawl (3) in the elevated position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The leg spring (8) has two legs (8a, 8b) and a wound central section to which the legs are connected

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3577292B1Motor vehicle door latch
Publication Date: 2021.09.15 KIEKERT AG
  • EP3577292B1 patent drawingFigure 1
  • EP3577292B1 patent drawingFigure 2
  • EP3577292B1 patent drawingFigure 3

AI summary

The object of the present invention is a motor vehicle door latch which is equipped with a locking mechanism (2, 3) predominantly consisting of a catch (2) and a pawl (3). Furthermore, a spring-impinged storage element (8) is provided for which maintains the pawl (3) in an elevated storage position during an opening process of the locking mechanism (2, 3) until the catch (2) is opened. According to the invention, the spring-impinged storage element (8) is formed as a leg spring (8) which is anchored in the latch with its one leg (8b) and with its other leg (8a) in the storage position maintains the pawl (3) in the elevated position and is braced on the catch (2) to this end.