Retraction Device with Moving Damper Housing for Extension Guides

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Solution Overview

Problem

Existing retraction devices for pull-out guides face challenges in improving the spring characteristic and reducing size while maintaining effective operation.

Innovation Solution

The retraction device features a latching hook with a through-opening for the piston rod, allowing the free piston rod end to be loosely attached or supported, and a spring attached to both the housing and coupling element, synchronizing movement with the locking hook and damper housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the spring is attached to the housing and coupling element with the locking hook having a through-opening for the piston rod, then the spring characteristic is enhanced and device size is reduced, but the structural complexity increases

Engineering Contradiction:
Improvespring characteristicVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the spring attachment points directly onto the housing and coupling element, eliminating the need for separate spring holders or mounting brackets. The locking hook with integrated through-opening serves multiple functions: it provides the mechanical linkage between damper housing and coupling element, and simultaneously serves as the attachment point for the spring. This merging of functions reduces the number of separate components while enhancing the spring characteristic through optimized force transmission.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The piston rod passes through the locking hook, creating a nested configuration where the locking hook is effectively nested within the damper assembly. The spring is then attached to external features of the housing and coupling element, creating a compact nested arrangement where multiple components occupy overlapping spatial volumes. This nesting reduces the overall device size while maintaining functional integrity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Volume of moving object

If the locking hook is coupled to the damper housing via piston rod through a through-opening, then the device size is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvedevice sizeVSAvoidmanufacturing precision
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The locking hook is designed as a multi-functional component that simultaneously serves as: (1) the mechanical coupling element between damper housing and coupling element, (2) the guide for the piston rod, (3) the attachment point for the spring, and (4) the structural element that transmits retraction forces. This multi-functionality reduces the need for separate dedicated components, thereby reducing overall device size while concentrating precision requirements into a single well-defined component geometry.

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

3Ease of manufacture

If the free piston rod end is loosely supported on the housing, then the ease of assembly is improved, but the stability of the connection decreases

Engineering Contradiction:
Improveease of assemblyVSAvoidconnection stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent employs a dynamic support arrangement where the free piston rod end is loosely supported on the housing rather than rigidly fixed. This allows the connection to adapt dynamically during operation: during assembly and normal operation, the loose support facilitates easy installation and accommodates manufacturing tolerances; during high-force retraction events, the rigid coupling through the locking hook and spring provides sufficient stability. The system transitions between compliance and rigidity based on operational conditions.

Inventive Principle:
Principle #15Dynamics

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 configuration enhances the spring characteristic and reduces the device's size, enabling efficient and synchronized movement of the locking hook and damper housing, improving the retraction mechanism's performance.

Implementation Method 1

a spring which biases the detent hook into the retracted end position

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

a damper for damping the retraction movement of the detent hook into the retracted end position

Methodology Applied
Scientific EffectDamping: Damping

Implementation Method 3

a damper for damping the retraction movement of the detent hook into the retracted end position

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3865002B1Closing device with a moving damper housing
Publication Date: 2023.09.06 HAEFELE SE & CO KG
  • EP3865002B1 patent drawingFigure 1a~1b
  • EP3865002B1 patent drawingFigure 2~3
  • EP3865002B1 patent drawingFigure 4~5

AI summary

In a retraction device (1) for an extension guide with a housing (2), with a detent hook (7) which is slidably guided in the housing (2) between a retracted end position and a tensioned end position, with a spring (18) which biases the detent hook (7) into the retracted end position, and with a damper (3) for damping the retraction movement of the detent hook (7) into the retracted end position, wherein the damper (3) has a damper housing (4) and a piston rod (5) slidably guided therein, the free piston rod end (6) of which protrudes from the damper housing (4) and is biased in the direction away from the damper housing (4), it is provided according to the invention that the detent hook (7) is pivotably mounted on a coupling element (13) which is linearly displaceable in the housing (2), in particular parallel to the detent hook (7).and that the free piston rod end (6) is supported on the housing (2) and a side (4a) of the damper housing (4) facing away from the free piston rod end (6) is supported on the coupling element (13).