Runner Pin with Dual Grooves for Noise-Free Roller Connection

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Solution Overview

Problem

Existing furniture castors with retaining rings in blind holes experience axial and radial play, leading to wobbling and noise when rolling over uneven surfaces, and current solutions like complex guide pins with plastic bushes are prone to wear and increased production complexity.

Innovation Solution

A guide pin with at least two spaced annular grooves for elastic retaining rings, arranged in the upper and lower thirds of the protruding section, ensures a play-free connection by using open spring snap rings or O-rings, eliminating axial and radial movement and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single retaining ring is used in a blind hole, then the structure is simple, but axial and radial play occurs causing noise and wobbling

Engineering Contradiction:
Improvestructure simplicityVSAvoidnoise and wobbling
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the single retaining ring solution into multiple retaining rings (at least two) arranged at different positions along the guide pin. This segmentation allows each ring to constrain different degrees of freedom, with the first ring preventing axial movement and the second ring preventing radial movement, thereby eliminating noise and wobbling while maintaining structural simplicity.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If a complex guide pin with plastic bushing is used, then noise is suppressed, but production complexity increases and the bushing wears over time

Engineering Contradiction:
Improvenoise suppressionVSAvoidproduction complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the plastic bushing component from the system, replacing it with a simpler metal guide pin and multiple retaining rings configuration. This extraction removes the wear-prone plastic component while reducing production complexity, as the guide pin can be produced as a single integrated metal part without embedded bushings.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the durable but complex plastic bushing with simpler, potentially replaceable retaining rings. The retaining rings are easier and cheaper to manufacture and install, and if wear occurs, they can be replaced independently without replacing the entire guide pin assembly.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Manufacturing precision

If the retaining ring groove width is precisely coordinated with the wire diameter, then play-free connection is achieved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvegroove width coordinationVSAvoidproduction ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the geometric parameters of the retaining rings, specifically making them larger in size relative to the groove dimensions. This parameter change allows for a deliberate play-free fit where the retaining ring is slightly larger than the groove, creating interference fit that eliminates radial play while maintaining ease of manufacture through standard sizing relationships.

Inventive Principle:
Principle #35Parameter changes

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 simple, cost-effective, and durable noise-free connection by preventing wobbling and movement of the guide pin, reducing assembly force and maintaining a frictional connection without wear, thus minimizing noise when rolling over uneven surfaces.

Implementation Method 1

an elastic retaining ring which is compressed radially and clamps onto the guide pin

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a resilient retaining ring with a slightly larger diameter than the blind hole is arranged. The part of the running pin that protrudes beyond the housing is inserted into the blind hole, with the retaining ring being compressed radially

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP2237972B1Runner pin for a roller
Publication Date: 2013.03.20 GROSS & FROELICH GMBH & CO KG
  • EP2237972B1 patent drawingFigure 1~2

AI summary

The invention relates to a roller, in particular furniture roller, having a housing which is rotatably fastened, by means of a runner pin (10) arranged vertically in an opening of the housing, to an object (16) to be supported by the roller, wherein the runner pin (10) has a first section (20) which is arranged in the opening of the housing and a second section (12) which projects beyond the housing. To create, in a simple and cost-effective manner, a runner pin which permanently prevents an undesired generation of noise as a result of relative movements between the runner pin (10) and the object (16) to be supported, it is proposed according to the invention that at least two annular grooves (28, 28') are provided in that section (12) of the runner pin (10) which projects beyond the housing, in which annular grooves (28, 28') in each case one elastic retaining ring (30, 30') is arranged without play.