Furniture Guide Rail Geometry for Stable Pinion Engagement

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Solution Overview

Problem

Existing guide units for movable furniture elements face challenges in maintaining reliable and convenient operation under varying loads, particularly due to increased friction and potential misalignment of guide rails during extension and insertion, which can lead to synchronization issues and wear.

Innovation Solution

The guide unit incorporates engagement rails with a head line that increases in distance from the guide rail's running surface as the furniture element is pulled out, ensuring consistent engagement of the rotary element and reducing leverage forces that cause misalignment, along with a center rail with converging running surfaces to mitigate tilting and stress on rails.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the guide rails are arranged parallel to each other in a pushed-in position, then the guide unit operates smoothly when inserted, but the engagement of the rotary element in the engagement rails deteriorates when the furniture element is pulled out due to tilting of the guide rails

Engineering Contradiction:
Improveengagement reliabilityVSAvoidparallel arrangement stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies the dynamics principle by making the head line distance dynamic rather than fixed. The distance between the head line of the engagement rail and the running surface of the guide rail increases as the furniture element is pulled out, compensating for the tilting of guide rails and maintaining consistent engagement of the rotary element throughout the movement range.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the geometric parameter of the engagement rail by designing the head line at an angle to the running surface. This parameter change allows the distance to vary with displacement, ensuring that the rotary element maintains proper engagement even as the guide rails tilt during extension and insertion.

Inventive Principle:
Principle #35Parameter changes

2Force

If bearing means are moved back and forth during extension and insertion, then friction is reduced, but the displacement of bearing means causes disturbance in the parallel arrangement of guide rails

Engineering Contradiction:
Improvefriction reductionVSAvoidparallel arrangement stability
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The patent introduces the engagement rail with the angled head line as an intermediary element that mediates between the moving bearing means and the guide rails. This intermediary compensates for the disturbances caused by bearing means displacement, maintaining the functional relationship between components despite the loss of perfect parallel arrangement.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the head line distance increases with displacement, then engagement of the rotary element is maintained under varying loads, but the guide rail geometry becomes more complex

Engineering Contradiction:
Improveengagement consistencyVSAvoidguide rail geometry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by modifying only the specific geometric feature of the engagement rail (the head line angle) rather than redesigning the entire guide rail system. This localized modification achieves the desired engagement consistency while minimizing overall system complexity.

Inventive Principle:
Principle #3Local quality

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 enhances the reliability and durability of the guide unit by maintaining secure engagement of the rotary element and reducing wear, while minimizing the risk of collisions and automatic extension issues, ensuring smooth and synchronized movement under different loads.

Implementation Method 1

bearing means acting between the guide rails which reduce friction

Methodology Applied
Scientific EffectRolling friction reduction: Roller

Implementation Method 2

a rotary element which engages in at least one engagement rail

Methodology Applied
Scientific EffectGear engagement: Gear

Data Source

PatentEP2422650B1Guide unit for a moveable furniture element
Publication Date: 2016.05.11 GRASS GMBH
  • EP2422650B1 patent drawingFigure 1~2
  • EP2422650B1 patent drawingFigure 3~5

AI summary

The unit (1) has bearing units acting among a body rail (10), a center rail (11) and an excerpt rail (12), and engaging rails (4, 5) provided in installed condition during movement of a movable furniture element along opposite directions. A pinion (2) is engaged into one of the engaging rails, where the engaging, body, center and excerpt rails are coupled with each other. A head line exhibits distance to a running surface on an engaging side of the engaging rails, where the distance is increased depending on a shift of the furniture element against a retracted position.