Pull-Out Guide Latch Cam for Absorbing Drawer Closure Impulses

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Solution Overview

Problem

Generic opening devices for pull-out guides face high stress and installation space restrictions due to the need to withstand high impulses during drawer closure, which requires reinforcing components of the latching mechanism.

Innovation Solution

A spring-loaded cam in the locking mechanism absorbs impulse peaks by yielding to pressure and then springing back, while a second energy accumulator further cushions these peaks without impairing the primary energy store's function, allowing the system to manage high forces without material reinforcement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the components of the latching mechanism are dimensioned to withstand high impulses during drawer closure, then the reliability and strength of the mechanism is improved, but the installation space required increases due to the need for reinforced components

Engineering Contradiction:
Improvewithstand high impulsesVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent introduces a cam with spring loading that is pre-configured to absorb impulse peaks before they reach the locking mechanism components. The spring-loaded cam yields to pressure during high-impulse events and then springs back, cushioning the shock in advance and protecting the locking pawl and other components from excessive stress without requiring them to be oversized or reinforced.

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

Solution Approach 2:

The spring-loaded cam acts as an intermediary element between the control element and the locking mechanism components. It mediates the force transmission by absorbing and dampening impulse peaks, allowing the locking mechanism to function reliably with smaller, less robust components that would otherwise be required to directly withstand the full force of hard drawer closure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the cam is spring-loaded to absorb impulse peaks, then the stress on locking mechanism components is reduced, but the device complexity increases due to the additional spring component

Engineering Contradiction:
Improvestress on componentsVSAvoidspring-loaded cam mechanism
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the spring loading directly into the cam structure, making the cam itself spring-loaded rather than adding a separate spring component. The spring is integrated into the cam's design, combining the cam's force transmission function with the spring's shock absorption function into a single unified component, thereby reducing overall device complexity while still providing impulse peak absorption.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a second energy accumulator is added to further cushion impulse peaks, then the reliability of the latching mechanism is improved, but the device complexity and number of components increases

Engineering Contradiction:
Improvecushion impulse peaksVSAvoidnumber of energy accumulators
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the energy absorption function into two distinct stages: the first energy accumulator (spring-loaded cam) handles normal impulse peaks during drawer closure, while the second energy accumulator specifically targets and cushions exceptional high-impulse events. This segmentation allows each energy accumulator to be optimized for its specific function, improving overall reliability without requiring a single oversized component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second energy accumulator is designed to activate only under exceptional conditions (hard drawer closure with heavy load), providing partial or excessive action only when needed. During normal operation, the first energy accumulator suffices, and the second remains inactive or minimally engaged, thereby adding reliability for extreme cases without significantly increasing complexity during routine use.

Inventive Principle:
Principle #16Partial or excessive action

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 effectively reduces stress on components and maintains the functionality of the pull-out guide by absorbing impulse peaks, thereby alleviating installation space constraints.

Implementation Method 1

the cam can yield to the pressure of the control element to a predetermined extent and then spring back into the starting position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a first force accumulator 12 fixed in the housing 7 of the latching mechanism, which exerts a force on a control element 13 coupled to the locking pawl 8

Methodology Applied
Scientific EffectMechanical energy storage: Mechanical Accumulator

Implementation Method 3

a second energy accumulator 10 is fixed in the housing of the latching mechanism, which holds the component in an end position pushed onto the housing, with the force exerted on the component by the second energy accumulator being greater than that of the first energy accumulator

Methodology Applied
Scientific EffectMechanical energy storage: Mechanical Accumulator

Data Source

PatentEP2266437B1Opening device for an extending guide and extending guide
Publication Date: 2014.12.24 PAUL HETTICH GMBH & CO KG
  • EP2266437B1 patent drawingFigure 1~2
  • EP2266437B1 patent drawingFigure 3a~3d
  • EP2266437B1 patent drawingFigure 4

AI summary

The device (3) has an engaging pawl (8) movable along a guidance unit or recess. An energy storage unit i.e. compression spring, is fixed in a housing (7) of an engagement mechanism. A control element is coupled with the engaging pawl and movable along a control curve. The control element is fixed against force of the energy storage unit by the engaging pawl in a closing position of a pull-out guidance unit. The control curve is fixed at the housing in a spring loaded manner. Another energy storage unit i.e. traction spring, is designed as a rubber part. An independent claim is also included for a pull-out guidance unit that comprises a running rail.