Furniture Drawer Ejection Device with Segmented Deceleration Path

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Solution Overview

Problem

Existing drive devices for movable furniture parts, such as drawers, face issues with high acceleration during ejection due to springs designed for loaded states, leading to hard impacts and increased energy consumption during closing, as damping devices are active during ejection and require additional user effort to tension the energy store.

Innovation Solution

A drive device with a carriage and driver that accelerates the movable furniture part over a first distance, then decelerates it over a second distance using controlled braking forces, with a control element that moves relative to the driver and carriage, allowing for optimized operating forces and reduced material stress during closing, featuring a guideway with angled sections to manage friction and locking noises.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If springs are designed for loaded state, then ejection force is sufficient for heavy drawers, but acceleration becomes excessively large for empty drawers causing hard impact

Engineering Contradiction:
Improveejection forceVSAvoidhard impact
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The ejection path is segmented into two distinct phases: a first path where the movable furniture part is accelerated by the spring force, and a second path where only the driver moves relative to the slide while the furniture part is decelerated. This segmentation allows different force regimes to apply at different stages, resolving the contradiction between needing high force for loading and avoiding impact for empty states.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling between the driver and slide is made dynamic through the control element, which can transition between coupled and decoupled states. During the first path, the control element couples the driver to the slide for acceleration; during the second path, it decouples them to allow independent motion and apply braking forces. This dynamic coupling adapts the system behavior to the actual load conditions.

Inventive Principle:
Principle #15Dynamics

2Speed

If damping device is active during ejection, then opening speed is controlled, but energy is drawn from spring storage unit increasing user effort during closing

Engineering Contradiction:
Improveopening speedVSAvoiduser effort during closing
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The damping action is applied periodically rather than continuously - specifically during the second path of the ejection stroke when the driver moves relative to the slide. This timed application of damping controls opening speed at the critical phase near full extension while minimizing energy consumption throughout the entire cycle, reducing the effort needed during closing.

Inventive Principle:
Principle #19Periodic action

3Use of energy by moving object

If driver is coupled to slide throughout closing movement, then energy storage device is tensioned efficiently, but control element cannot engage locking mechanism quietly

Engineering Contradiction:
Improvetensioning efficiencyVSAvoidlocking noises
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The closing movement is segmented into two distinct phases: a first path where the driver moves the slide against spring force for efficient tensioning, and a second path where the control element decouples and moves independently to engage the locking mechanism. This segmentation allows the locking action to occur separately from the high-force tensioning phase, enabling quiet engagement without compromising tensioning efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control element acts as an intermediary between the driver and the locking mechanism. It receives motion from the driver during the first path, then independently executes the locking engagement during the second path. This intermediary function allows the locking mechanism to be activated with minimal force and noise while the main driving forces are already being applied to the slide.

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 smoother operation by reducing braking forces during opening, preventing hard impacts, and minimizing user effort by allowing self-closing mechanisms to handle the furniture part, resulting in quieter and more efficient handling of movable furniture parts.

Implementation Method 1

a power storage device (22), which can be coupled to a movable furniture part (3) via a driver (12), wherein, upon unlocking of the ejection device (6), the movable furniture part (3) is accelerated from an over-press or closed position

Methodology Applied
Scientific EffectSpring energy storage: Spring

Implementation Method 2

The guide track (16) is oriented at an angle to the direction of action of the energy storage device (22), in which a pin (42) is guided. The pin (42) can then be moved in the guide track (16) to slowly move the control element (40) into the detent position

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3484325B1Drive device for a movable furniture part and method for closing a movable furniture part
Publication Date: 2020.09.02 PAUL HETTICH GMBH & CO KG
  • EP3484325B1 patent drawingFigure 1
  • EP3484325B1 patent drawingFigure 2
  • EP3484325B1 patent drawingFigure 3

AI summary

The invention relates to a drive device for a movable furniture part (3), in particular a drawer, which drive device comprises an ejection device (6), which has a slide (30), which is preloaded by a force accumulator (22) and which can be coupled to a movable furniture part (3) by means of a driver element (12), wherein, when the ejection device (6) is unlocked, the movable furniture part (3) is accelerated from an overpressing position or closed position over a first travel distance in an opening direction by means of the slide (30) and the driver element (12) and the movable furniture part (3) can be moved over a second travel distance after the first travel distance, at which second travel distance the driver element (12) can be moved relative to the slide (30), wherein, during a closing movement, the driver element (12) moves over a third travel distance against the force of the force accumulator (22) and the driver element (12) is coupled to the slide (30) by means of a control element (40) along the third travel distance, which control element can be moved relative to the driver element (12) along a fourth travel distance until a closed position is reached.