Drawer Pull-Out Guide With Overload-Decoupling Forced Control

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Solution Overview

Problem

Existing drawer slide systems with forced controls, such as rack and pinion arrangements, are prone to damage from overloading or mishandling, leading to non-synchronous movement and potential breakage.

Innovation Solution

Incorporation of an overload protection device that reversibly decouples the force flow when a predetermined threshold is exceeded, using mechanisms like self-switching clutches or ratchet wheels, to prevent damage and ensure slip-free movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a forced control (rack and pinion arrangement) is used to precisely control the relative movement of rails and carriages, then the synchronization and precision of movement is improved, but the risk of damage from overloading or mishandling increases

Engineering Contradiction:
Improvemovement synchronization precisionVSAvoidresistance to overload damage
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent incorporates an overload protection device (clutch mechanism) into the forced control system beforehand. This device includes a clutch disc, pressure plate, and spring arrangement that can reversibly decouple the synchronization wheel from the rack when excessive forces are detected, preventing damage to the precision components while maintaining normal synchronized operation under normal conditions

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

2Reliability

If the forced control components are made more robust to prevent damage, then the reliability under overload conditions is improved, but the complexity of the device increases

Engineering Contradiction:
Improveresistance to overload damageVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a clutch mechanism as an intermediary element between the synchronization wheel and the rack. This clutch acts as a mediator that can reversibly disconnect the force flow when overload occurs, protecting the precision components without requiring them to be inherently more robust. The clutch includes a clutch disc, pressure plate, and spring assembly that collectively provide the protection function

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the overload protection device is made more sensitive to detect excessive torque, then the protection effectiveness is improved, but the risk of false decoupling during normal operation increases

Engineering Contradiction:
Improveoverload detection accuracyVSAvoidnormal operation stability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent employs a spring-based clutch mechanism where the decoupling threshold is determined by the spring preload force. By carefully selecting the spring constant and preload, the system achieves optimal sensitivity - the spring compresses under normal operational variations without triggering decoupling, but releases to decouple the synchronization wheel when excessive torque is applied, providing reliable overload protection without false positives

Inventive Principle:
Principle #35Parameter changes

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 overload protection device effectively prevents damage to the forced control components by interrupting the power flow during excessive torque, allowing for safe reconnection when conditions return to normal, thus maintaining the integrity and functionality of the drawer slide system.

Implementation Method 1

the forced control has a synchronization wheel designed as a toothed wheel, which interacts with a running surface arranged or formed on the rails and/or with a running surface of a carriage that is slidably mounted between the rails

Methodology Applied
Scientific EffectRatchet mechanism: Ratchet

Implementation Method 2

the overload protection device has at least one—preferably self-switching—clutch, which decouples the forced control from a predetermined threshold value

Methodology Applied
Scientific EffectOverload protection via clutch:

Implementation Method 3

which decouples the forced control from a predetermined threshold value. In this context, for example, slipping clutches can be advantageously used, which interrupt the power flow reversibly without external influence when a defined torque is reached

Methodology Applied
Scientific EffectElastic energy storage: Spring

Data Source

PatentEP2608697B1Pull-out guide for drawers
Publication Date: 2014.01.08 JULIUS BLUM GMBH
  • EP2608697B1 patent drawingFigure 1
  • EP2608697B1 patent drawingFigure 2a~2d
  • EP2608697B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a pull-out guide (4) for drawers (3), comprising a body rail (5) to be fastened to a furniture body (2), a drawer rail (7) to be fastened to the drawer (3), and a center rail (6) movably mounted between the body rail (5) and the drawer rail (7), wherein the relative motion sequence of the rails (5, 6, 7) is determined by means of a forced control unit (10), wherein the forced control unit (10) has a synchronization wheel (9) designed as a gear wheel, which interacts with a running surface (5a, 5b) arranged or formed on the rails (5, 6, 7) and/or with a running surface (5a) of a carriage (12, 13), which is slidably mounted between the rails (5, 6, 7), wherein an overload protection mechanism (11) is provided, by means of which the forced control unit (10) of the rails (5, 6, 7) can be reversibly lifted.