Drawer Pull-Out Guide Geometry to Prevent Extension Droop

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Solution Overview

Problem

Drawer pull-out guides often cause drawers to drop when fully extended, leading to instability and requiring manual force to close, especially when loaded, resulting in a less aesthetically pleasing appearance.

Innovation Solution

The drawer pull-out guide features a catwalk with a horizontal first and second guide section connected by an inclined third section, where rolling elements of varying diameters are arranged one above the other, allowing the rear end to lower and the front end to raise, maintaining a horizontal rail alignment under load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional drawer pull-out guide is used, then the drawer can be pulled out and stored, but the drawer drops considerably when fully pulled out and does not remain balanced

Engineering Contradiction:
Improvedrawer pull-out operationVSAvoiddrawer balance
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The guide section transitions from a static horizontal configuration to a dynamic inclined configuration that actively compensates for drawer droop. The inclined guide section is designed with specific geometry to counteract gravitational effects on the rolling elements, maintaining drawer balance throughout the pull-out motion rather than relying on passive horizontal guidance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The guide section geometry is changed from horizontal to inclined at a predetermined angle. This parameter change in the guide section's orientation allows the rolling elements to follow a trajectory that compensates for drawer droop, transforming the mechanical behavior to maintain balance while preserving ease of operation.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the drawer is heavily loaded, then it can be stored, but the drawer requires additional manual forces to close and is more difficult to operate

Engineering Contradiction:
Improvedrawer load capacityVSAvoiddrawer closing effort
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The inclined guide section is designed to preemptively counteract the droop effect that occurs under heavy loads. By positioning the guide section at a predetermined angle, the system creates a mechanical advantage that offsets the additional weight, reducing the manual force required to close the drawer while maintaining full load capacity.

Inventive Principle:
Principle #9Preliminary anti-action

3Ease of operation

If the drawer lowers when fully pulled out, then it can be opened, but it conveys a lower-quality visual appearance

Engineering Contradiction:
Improvedrawer openingVSAvoiddrawer position stability
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The guide section transitions from a static horizontal configuration to a dynamic inclined configuration that actively compensates for drawer droop. The inclined guide section is designed with specific geometry to counteract gravitational effects on the rolling elements, maintaining drawer balance throughout the pull-out motion rather than relying on passive horizontal guidance.

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 design reduces drawer lowering, maintaining balance and ease of operation, while providing a higher-quality visual appearance by ensuring the drawer remains stable and easier to close.

Implementation Method 1

at least one carriage with at least four load-transmitting rolling elements being mounted between the rails, which run on a catwalk of a rail

Methodology Applied
Scientific EffectRolling: Roller

Data Source

PatentEP2506738B1Drawer pull-out guide
Publication Date: 2015.03.18 JULIUS BLUM GMBH
  • EP2506738B1 patent drawingFigure 1a~1b
  • EP2506738B1 patent drawingFigure 2
  • EP2506738B1 patent drawingFigure 3

AI summary

The invention relates to a drawer pull-out guide (4), comprising a body rail (5) to be fastened to a furniture body (2) and comprising at least one pull-out rail (6) slidably supported relative thereto, which is supported so as to be movable between a closed position and an open position, wherein at least one carriage (9) having at least four load-transmitting rolling elements (13a, 13b; 14a, 14b) is supported between the rails (5, 6), which rolling elements run on a runway (8) of a rail (5), wherein the runway (8) has a first substantially horizontal, straight guide section (8a) in the rear end area and a second substantially horizontal, straight guide section (8c) in the front end area, wherein the first and the second guide sections (8a, 8c) are interconnected by a third guide section (8b) that extends downward at an angle from the first (8a) to the second guide section (8c), wherein two rolling elements (13a, 13b, 14a, 14b) each are arranged one on top of the other in the first straight guide section (8a) and in the second straight guide section (8c) in the closed position, wherein of the rolling elements (13a, 13b) arranged one on top of the other in the first guide section (8a), the lower rolling element (13b) has a larger diameter than the upper rolling element (13a), and wherein in the second guide section (8c), the upper rolling element (14a) has a larger diameter than the lower rolling element (14b).