Vehicle Seat Locking Device with Clamping Eccentric

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing vehicle seat locking devices require significant installation space and are heavy, lacking an efficient mechanism for both locking and unlocking with adequate force distribution.

Innovation Solution

A locking device design featuring a prestressed compression spring supporting a clamping eccentric, which exerts a closing moment on the pawl during locking and ejects the counter-element with high force during unlocking, optimized by lever arm ratios for balanced forces and reduced installation space, along with a pivoting unlocking mechanism and catch eccentric for crash support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional locking device with separate locking and ejection mechanisms is used, then reliable locking is achieved, but installation space increases and weight increases

Engineering Contradiction:
Improvelocking reliabilityVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent combines the locking function and ejection function into a single integrated mechanism. The clamping eccentric serves dual purposes: it provides locking through the pawl-clamping surface interaction and enables ejection by pivoting to disengage the pawl from the counter-element. This merging of functions eliminates the need for separate locking and ejection mechanisms, thereby reducing installation space while maintaining reliable locking.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The clamping eccentric is designed as a multi-functional component that performs both locking and ejection operations. By rotating about the first axis, it alternately engages the pawl for locking and disengages it for ejection. This universal component approach allows a single part to fulfill multiple functions that traditionally required separate mechanisms, reducing overall device complexity and space requirements.

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

2Force

If high ejection force is required for unlocking, then reliable unlocking is achieved, but locking forces increase and installation space increases

Engineering Contradiction:
Improveejection forceVSAvoidinstallation space
Core Design Contradiction:
ForceVSArea of stationary object

Solution Approach 1:

The patent employs eccentric geometry in the clamping eccentric component, which rotates about an axis offset from its geometric center. This curved, asymmetric shape creates varying leverage ratios during rotation: when positioned to eject, it provides high mechanical advantage for generating strong ejection force with minimal space; when positioned to lock, it maintains secure engagement. The eccentric curvature allows force amplification without requiring additional space or complex mechanisms.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If the clamping eccentric is spring-loaded into locking position, then self-locking is achieved, but device complexity increases

Engineering Contradiction:
Improveself-locking capabilityVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The compression spring automatically biases the clamping eccentric into its locking position, enabling self-locking without requiring external actuation or complex control systems. The spring continuously applies force to maintain engagement between the pawl and clamping surface, ensuring the locking function is passively maintained. This self-service mechanism reduces device complexity by eliminating the need for additional locking actuators or control logic while enhancing reliability through automatic engagement.

Inventive Principle:
Principle #25Self-service

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 solution achieves a compact, lightweight locking device with high ejection force and low locking forces, reducing installation space and preventing rattling noises through balanced torque and force distribution, while ensuring secure locking and easy unlocking.

Implementation Method 1

a prestressed compression spring being provided which is supported at one end on an arm of the clamping eccentric, spring-loading it into its locking position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a first lever arm L1 between the point of application of the compression spring on the pawl and the second axis can be greater than a second lever arm L2 between the point of application of the compression spring on the clamping eccentric and the first axis

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP2704919B1Locking device and vehicle seat
Publication Date: 2018.03.21 ADIENT LUXEMBOURG HLDG SARL
  • EP2704919B1 patent drawingFigure 1
  • EP2704919B1 patent drawingFigure 2
  • EP2704919B1 patent drawingFigure 3

AI summary

The invention relates to a locking device for a vehicle seat, in particular a motor vehicle seat, with a latch (9) which is mounted pivotably about a second axis (3') and is intended for locking a counter element, with a clamping eccentric (6) which is mounted pivotably about a first axis (2') parallel to the second axis (3') and, by interaction with a first functional surface (34) of the latch (9), secures a locked state of the latch (9), wherein, in the locked state, the clamping eccentric (6) acts in a spring-loaded manner on the first functional surface (34) via a clamping surface (23), wherein the clamping eccentric (6) is moveable from the locking position thereof into the unlocking position thereof, and wherein a pretensioned compression spring (36) is provided, said compression spring being supported at one end thereof on an arm of the clamping eccentric (6) in a manner spring-loading the latter into the locking position thereof and, at the other end thereof, acting upon the latch (9) in the unlocking direction.