Self-adjusting Buffer Stop with Cam Lock Mechanism

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Solution Overview

Problem

Existing self-adjusting buffer devices for motor vehicle components, such as rear trunk lids, face issues with long-term retention due to clamping and adhesion-based prestressing methods, which can lead to instability and high manufacturing costs due to multiple separate parts.

Innovation Solution

A self-adjusting buffer device with a rod-shaped buffer head and base, featuring an annular ring that rotates to lock the buffer head in place, utilizing a cam effect and flexible tabs for precise adjustment and locking, eliminating the need for separate prestressing components and reducing manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If clamping and adhesion-based prestressing methods are used in existing self-adjusting buffer devices, then the buffer device can be assembled with multiple separate parts allowing adjustment, but the long-term retention stability deteriorates and manufacturing costs increase

Engineering Contradiction:
ImproveadjustabilityVSAvoidlong-term retention stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent merges the prestressing function and locking function into a single integrated cam mechanism. The cam profile geometry simultaneously provides the prestressing force through its inclined surface and the locked position through its engagement with the cam follower, eliminating the need for separate clamping and adhesion-based prestressing components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the clamping and adhesion-based mechanical system with a cam-based mechanical system. The cam mechanism uses geometric conversion of rotational motion into linear prestressing force, providing more reliable long-term retention without relying on friction-based adhesion that degrades over time.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If clamping and adhesion-based prestressing methods are used in existing self-adjusting buffer devices, then the buffer device can be assembled with multiple separate parts allowing adjustment, but manufacturing costs increase due to multiple separate parts

Engineering Contradiction:
ImproveadjustabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple functions (prestressing, locking, and positioning) into a single cam component, reducing the total number of parts that need to be manufactured, assembled, and quality-checked. This integration directly reduces manufacturing costs while preserving the self-adjusting capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cam mechanism serves multiple functions simultaneously: it provides the prestressing force, maintains the locked position, and allows for self-adjustment. This multi-functionality eliminates the need for separate dedicated components for each function, simplifying manufacturing.

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

3Stability of the object's composition

If the buffer head is locked in position using traditional methods, then the buffer head remains stable, but internal stresses cause fatigue and reduce anti-vibration performance

Engineering Contradiction:
Improvebuffer head position stabilityVSAvoidanti-vibration performance
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent replaces traditional clamping mechanisms that create internal stresses with a cam-based system. The cam mechanism applies external geometric constraints through the cam follower, maintaining position stability without inducing harmful internal stresses in the buffer head material.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The cam follower acts as an intermediary between the cam mechanism and the buffer head. It transfers the positioning force from the cam to the buffer head without creating concentrated stress points, thereby maintaining stability while preserving the buffer head's anti-vibration properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides a stable, long-term retention mechanism that maintains precision adjustment and anti-vibration performance without internal stresses, reducing fatigue and manufacturing costs while simplifying the assembly process.

Implementation Method 1

the outer annular surface of the ring is provided with a cam track defining a cam profile which co-operates with at least one cam follower provided on the upper edge of the bore

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 2

the ring comprising a lower edge defining a thrust ramp designed to, when the ring, produce a cam effect with the axial bore in a recess in the bottom of the base and allow the raising of the buffer head

Methodology Applied
Scientific EffectCam effect: Cam

Implementation Method 3

the grooves in the bore being intended to engage in the grooves of the rod-shaped buffer head which has the effect of increasing the friction forces while allowing relative movement by notch

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3058158B1Self-adjusting buffer stop device
Publication Date: 2020.06.03 A RAYMOND & CO SCS
  • EP3058158B1 patent drawingFigure 1~2
  • EP3058158B1 patent drawingFigure 3
  • EP3058158B1 patent drawingFigure 4~5

AI summary

The invention relates to a buffer device having a self-adjusting abutment, which includes a rod-shaped buffer head (5) which has a flat section over the length thereof and adjacent ridges or grooves (6) and a base (8) in which the rod-shaped buffer head can be inserted axially by notch. Said device also includes an annular ring (7) inserted axially in an axial bore of the base and having a lower edge defining a thrust ramp. The ring has a lower surface having a smooth band and an adjacent ridged band such that the rotating actuation of the ring causes the raising of the buffer head and the locking thereof in an axial position.