Drawer Slide Latch Mechanism for Stable Full-Open Position

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Solution Overview

Problem

Existing automatic displacement mechanisms for pull-out furniture parts often fail to reliably reach the fully open end position without accidental closure due to excessive acceleration and impact, and lack effective solutions for maintaining the open position.

Innovation Solution

The mechanism is redesigned to operate in the opposite direction of movement by placing the latch housing at the end of the outer rail and the driver on the middle rail or running rail, with optional damping devices to control the spring's effect, ensuring smooth transition to the fully open position and preventing accidental closure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a preloaded spring is used to automatically retract the drawer when approaching the fully pushed-in position, then the drawer can be automatically closed and prevented from accidental opening, but excessive acceleration and impact occur during the retraction process

Engineering Contradiction:

Improveautomatic closing functionVSAvoidexcessive acceleration and impact

Core Design Contradiction:

Extent of automationVSObject-affected harmful factors

Solution Approach 1:

A damping device is integrated into the latch housing to provide beforehand cushioning for the spring-driven retraction process. The damping device includes a damping element that is compressed during drawer opening and then releases to control the retraction speed, preventing excessive acceleration and impact while maintaining the automatic closing function.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The damping device acts as an intermediary between the preloaded spring and the drawer, mediating the force transmission. The damping element controls the spring's retraction force, transforming the harsh direct spring action into a controlled, gradual movement that avoids impact while preserving the automatic closing capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If the drawer is opened too forcefully to reach the fully open end position, then the drawer can be opened quickly, but the reaction force of the impact causes the drawer to be partially closed again

Engineering Contradiction:

Improveopening speedVSAvoidability to maintain open position

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The latch component is designed to engage with the driver at a predetermined position before the fully open end position is reached. This preliminary engagement action occurs automatically when the drawer approaches the open position, latching the drawer in place before any rebound can occur, thus maintaining reliability despite high opening speeds.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The latch mechanism operates automatically without user intervention. As the drawer is pulled open, the driver on the running rail automatically engages the latch component in the latch housing at the correct moment, causing the latch to pivot and lock the drawer in the open position, preventing rebound closure.

Inventive Principle:

Principle #25Self-service

3Reliability

If a latch component is added to fix the drawer in the fully open position, then accidental closure can be prevented, but the device complexity increases

Engineering Contradiction:

Improveability to maintain open positionVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The latch component serves multiple functions: it automatically engages to prevent rebound closure when the drawer is opened forcefully, maintains the drawer in the fully open position to prevent accidental closure, and works seamlessly with the existing spring-driven automatic closing mechanism. This multi-functionality achieves reliable open position maintenance without significantly increasing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The latch mechanism is integrated into the existing automatic displacement mechanism structure. The latch housing is positioned on the guide rail and works in coordination with the driver on the running rail, merging the latching function with the existing spring and driver components rather than adding a completely separate system.

Inventive Principle:

Principle #5Merging (Combining)

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 design allows for automatic and controlled opening of pull-out furniture parts to their full extent, reducing the risk of accidental closure and maintaining the open position effectively, while minimizing impact and ensuring smooth operation.

Implementation Method 1

a spring arrangement with an elongated coil spring is provided, which is prestressed in the compressed state and has a first end and a second end

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 2

Some of the known automatic retractors are already provided with damping devices

Methodology Applied

Scientific EffectDamping: Damping

Data Source

PatentEP1743550B1Displacement device for furniture extensions, in particular drawers

Publication Date: 2008.03.26 ALFIT AKTIENGES

Figure 1~3
Figure 4~7
Figure 8~10

AI summary

Sliding device (22) has a catch housing (24), which is provided in the end area of the respective outermost rail (16,20) whereby the end region is attached in the opening position of the drawable furniture part. The attachment is provided in the area of the other outermost rail, which is near to the end area approaching opening position, or of the central rail.