Drawer Pull Lever Coupling for Low-Force Retraction

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Solution Overview

Problem

Existing drawer retraction mechanisms require significant user effort, especially for voluminous and heavily loaded drawers, due to the tensioning of the driver or tension lever against spring force.

Innovation Solution

A pull lever with at least two coupling points or a movable coupling point that can be positioned differently along its length, allowing for efficient coupling and decoupling with the drawer or rail during opening and closing, enabling the energy accumulator to be charged with lower forces and providing a smoother retraction process by distributing the pull-in force directly to the drawer rail.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single coupling point is used on the driver, then the structure is simple, but significant user effort is required to tension the driver against spring force during opening

Engineering Contradiction:
Improveuser effort during openingVSAvoiddriver structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The driver is divided into two separate coupling points (first coupling point and second coupling point) spaced apart along its length. During opening, the first coupling point engages with the middle rail while the second coupling point remains disengaged, allowing the driver to be tensioned with lower force. During closing, the second coupling point engages with the drawer rail to apply the full retraction force.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the driver tensions against spring force during opening, then the drawer can be opened, but considerable user effort is required especially for voluminous and heavily loaded drawers

Engineering Contradiction:
Improveeffort to open drawerVSAvoiduser force during opening
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The opening process is divided into two stages: first, the middle rail is pulled out and engages the first coupling point, which tensions the driver with lower force; second, the drawer rail is pulled out and engages the second coupling point, which then tensions the driver against the full spring force. This preliminary engagement with the first coupling point reduces the initial effort required.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the pull-in force is applied directly to the drawer rail during closing, then the retraction is smoother and more controlled, but the coupling mechanism becomes more complex

Engineering Contradiction:
Improvesmoothness of retractionVSAvoidcoupling mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

Different coupling points are optimized for different functions: the first coupling point is designed for low-force engagement with the middle rail during opening, while the second coupling point is designed for high-force engagement with the drawer rail during closing. This local specialization allows each coupling point to be simple in its specific function while the overall system achieves smooth, controlled retraction.

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

Reduces the initial retraction force required, making it easier to open and close drawers, and allows for a more controlled and damped movement, enhancing user experience by minimizing the feeling of the drawer being pulled out of their hand during retraction.

Implementation Method 1

a driver (10) which can be acted upon by an energy accumulator (18) for applying force to the movable furniture part (3) or the rail (6) of the drawer pull-out guide (4)

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP2464258B1Pull-in or pull-out device for moving a movable furniture part
Publication Date: 2016.07.20 JULIUS BLUM GMBH
  • EP2464258B1 patent drawingFigure 1
  • EP2464258B1 patent drawingFigure 2
  • EP2464258B1 patent drawingFigure 3a~3c

AI summary

The invention relates to a pull-in or pull-out device (9) for moving a movable furniture part (3) or for moving a rail (6, 7) of a drawer pull-out guide (4) relative to a furniture body (2), comprising a tappet (10) for applying force to the movable furniture part (3) or to the rail (6, 7) of the drawer pull-out guide (4), to which tappet force is or can be applied by means of a force accumulator (18), the tappet (10) having a pulling lever (15), which can be detachably coupled to the movable furniture part (3) or to the rail (6, 7) of the drawer pull-out guide (4), the pull-in or pull-out device being characterized in that the pulling lever (15) has either at least two coupling points (16a, 16b) or a coupling point (25) that is movable between two positions for detachably coupling the pulling lever (15) to the movable furniture part (3) or to the rail (6, 7) of the drawer pull-out guide (4), either the at least two coupling points (16a, 16b) or the two positions between which the movable coupling point (25) can be moved being arranged at a distance from each other along the length of the pulling lever (15).