Retraction device for retracting a movable part of an item of furniture or domestic appliance into an end position

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Solution Overview

Problem

Existing retraction devices for movable parts in furniture and household appliances often result in material-damaging collisions when the activator is incorrectly positioned, and they require additional return springs for correct engagement, leading to a less flexible arrangement and difficulty in adding damping devices.

Innovation Solution

The retraction device incorporates a deflection section in the guideway and a shaped outer contour for the driver, allowing it to pivot back and engage the activator without an additional return spring, and includes a damping mechanism to control the retraction movement, ensuring correct engagement and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a retraction device uses a driver guided by guide pins in a guide track with an angled end section, then the driver can be released from the activator at the end position, but if the driver is already in the end position without activator engagement, a collision occurs causing material damage

Engineering Contradiction:
Improvecorrect engagement of driver with activatorVSAvoidmaterial-damaging collision
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The guide track includes a deflection section with a restoring torque mechanism that activates before the driver reaches the end position. This restoring torque gently guides the driver back to the engagement position, preventing harmful collisions with the activator by cushioning the correction process in advance

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

Solution Approach 2:

The deflection section creates a feedback mechanism where the guide track geometry itself provides a restoring force when the driver deviates from the correct engagement position. This passive feedback system automatically corrects misalignment without additional active components

Inventive Principle:
Principle #23Feedback

2Reliability

If an additional return spring is added to pivot the driver back to the engagement position, then correct engagement is ensured, but the device becomes more complex and flexible arrangement is reduced

Engineering Contradiction:
Improvecorrect engagement of driver with activatorVSAvoidnumber of spring elements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The guide track combines multiple functions: guiding the driver's linear movement, providing the restoring torque through its deflection section geometry, and enabling the pivoting motion. This merging of guidance and restoration functions into a single component eliminates the need for separate return springs

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The guide track is designed as a multi-functional element that simultaneously provides mechanical guidance, positional feedback, and restoring force generation. This universal component replaces what would traditionally require multiple separate elements including return springs

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If the retraction spring is coupled directly to the driver and guide track, then the driver can pivot back into position, but the arrangement of components becomes less flexible and damping device integration is difficult

Engineering Contradiction:
Improverestoring torque for driver positioningVSAvoidflexibility in component arrangement
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system is segmented into functionally independent modules: the guide track handles positioning and restoring torque, the coupling piece handles force transmission, and the damping device handles motion control. This segmentation allows each component to be optimized independently and facilitates flexible arrangement and integration of damping devices

Inventive Principle:
Principle #1Segmentation

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 allows the driver to correctly engage the activator even when positioned incorrectly, simplifying the device's construction and adding a damping function for controlled retraction, reducing mechanical resistance and noise.

Implementation Method 1

coupled to a power storage device, which is movable between an end position and a park position

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The guide track's clearance section for the driver and/or an outer contour of the driver are designed such that, when the driver pivots into position, it experiences a restoring torque from the energy storage device

Methodology Applied
Scientific EffectGeometry: Geometry

Implementation Method 3

includes a damping mechanism to control the retraction movement, ensuring correct engagement and flexibility

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP3675691B1Retraction device for retracting a movable part of an item of furniture or domestic appliance into an end position
Publication Date: 2021.12.29 HETTICH HEINZE GMBH & CO KG
  • EP3675691B1 patent drawingFigure 1a~1b
  • EP3675691B1 patent drawingFigure 2a~2b
  • EP3675691B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a retraction device (10) for retracting a movable part of an item of furniture or domestic appliance into an end position, said device having a driver (21), which is guided along a guide path (13), is coupled to a force accumulator, and is movable between an end position and a parked position, wherein - the guide path (13) has an angled end portion (132), into which the driver (12) drives via at least one guide pin (121, 122) in the parked position so as to release an activator (6) of the movable part, and wherein - the guide path (13) has an evasion portion (133), into which the driver (12) can pivot via the at least one guide pin (121, 122) in the end position so as to evade the activator (6). The evasion portion (133) and/or an outer contour of the driver (12) are designed according to the invention such that, as the driver (12) pivots in, the driver (12) experiences a restoring moment through the force accumulator. The invention also relates to an item of furniture or domestic appliance with a movable part, in particular a sliding door, which has at least one retraction device (10) of this kind for the movable part.