Drawer Rail Gear Rack Mounting to Prevent Jamming

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Solution Overview

Problem

Existing rail systems for drawers often experience jamming due to the positive connection between the toothed rack and gearwheel, leading to undesired blocking of the drawer during normal use.

Innovation Solution

The toothed rack is mounted with limited vertical mobility, allowing it to pivot or bend relative to the rail, and is spring-mounted to give way in jamming situations, maintaining the form fit with the gearwheel while preventing tilting and jamming through a resilient or flexible connection, such as a film joint or adapter with an L-profile design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the toothed rack is rigidly connected to the rail, then the parallel guidance and synchronization are improved, but the risk of jamming increases due to the positive connection between toothed rack and gearwheel

Engineering Contradiction:
Improveparallel guidance precisionVSAvoidjamming resistance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The toothed rack is transformed from a rigid static component to a dynamic component capable of limited vertical movement. The resilient mounting allows the rack to adapt its position vertically, absorbing deviations and preventing jamming while maintaining engagement with the gearwheel during drawer movement

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The vertical position parameter of the toothed rack is made variable through resilient mounting. This allows the rack to change its vertical position dynamically during operation, accommodating tolerances and preventing the positive connection from causing jamming, while still maintaining sufficient engagement for synchronization

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the toothed rack is mounted with vertical mobility, then the jamming risk is reduced, but the synchronization precision may be compromised

Engineering Contradiction:
Improvejamming resistanceVSAvoidsynchronization precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The toothed rack is given partial vertical mobility - enough to prevent jamming but limited by the resilient mounting's characteristics. This partial action allows the rack to give way slightly in jamming situations while the elastic restoration force maintains sufficient engagement to preserve synchronization precision

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The resilient mounting acts as a beforehand cushioning element that absorbs potential jamming forces before they can cause blocking. The elastic deformation capacity provides a buffer that prevents the positive connection from leading to complete synchronization failure

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 solution enhances the running properties of the rail system by reducing the risk of jamming and ensuring smooth operation of the drawer, preventing tilting and maintaining precise parallel guidance.

Implementation Method 1

a resilient area (15) which allows the toothed rack (9) to pivot or bend relative to the rail (6) about an imaginary axis (A) running in the extension direction (13) of the rail (6), and thus to move with limited height

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The toothed rack is spring-mounted in the vertical direction, so that the toothed rack, which is spring-mounted in the vertical direction, can give way to the toothed wheel in any jamming situations, although the form fit between the toothed wheel and toothed rack is maintained

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP2515710B1Rail system for drawers
Publication Date: 2014.02.26 JULIUS BLUM GMBH
  • EP2515710B1 patent drawingFigure 1
  • EP2515710B1 patent drawingFigure 2a~2b
  • EP2515710B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a rail system (4) for drawers (3), comprising a body rail (6) to be fastened to a furniture body (2) and at least one drawer rail (7) that can be moved relative to the body rail (6), and comprising at least one gear rack (9) arranged on a rail (6, 7, 10) of the rail system (4), wherein the gear rack (9) can be pivoted or bent relative to the rail (6, 7, 10) to which said gear rack is fastened about an imaginary axis (A) extending in the pull-out direction (13) of the rail (6, 7, 10) and thus is mounted such that the gear rack can be moved vertically to a limited extent.