Pull-out guide
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Solution Overview
Problem
Pull-out guides for furniture lack effective and targeted lubrication, leading to issues such as foreign object and dirt impairments, uneven lubricant distribution, and excessive grease application, which affects running quality and function.
Innovation Solution
A pull-out guide with a rolling element cage made of a lubricant-containing material that diffuses lubricant to the moving surfaces, ensuring continuous lubrication and preventing excess lubricant from reaching non-contact surfaces, using processes like pressure impregnation and porous bodies to store and release lubricant as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grease is applied during manufacture, then the rolling elements are lubricated, but the lubrication is removed unintentionally and metering is difficult
Solution Approach 1:
The rolling element cage is pre-lubricated during manufacture with a precise amount of lubricant. This preliminary lubrication action ensures that the rolling elements receive the exact needed lubrication dose during assembly, preventing both insufficient and excessive lubrication while maintaining reliability throughout the product lifecycle.
Solution Approach 2:
The pull-out guide is designed with lubricant reservoirs and distribution channels that enable the system to automatically replenish lubricant to the rolling elements during operation. This self-service mechanism ensures continuous lubrication without external intervention, maintaining reliable lubrication retention while eliminating the need for manual reapplication.
2Reliability
If excess grease is applied, then the surfaces are covered, but material intensity increases and running quality deteriorates
Solution Approach 1:
The lubrication system is designed to deliver lubricant precisely where it is needed - directly to the contact surfaces of the rolling elements through targeted distribution channels. This local quality approach ensures complete surface coverage at the critical interfaces while minimizing grease consumption by preventing application to non-contact surfaces.
Solution Approach 2:
Instead of applying lubricant to all surfaces, the system applies lubricant partially - only to the specific contact surfaces of the rolling elements. This partial action approach achieves sufficient surface coverage for reliable lubrication while significantly reducing overall grease consumption and preventing the negative effects of excess lubricant.
3Device complexity
If the pull-out guide is not sealed, then the structure is simple, but foreign objects and dirt cause impairments
Solution Approach 1:
The pull-out guide incorporates sealing elements in the form of flexible lips or films that prevent dirt and foreign objects from entering the lubrication system. These thin film seals provide effective contamination protection while maintaining relatively simple device complexity, as they can be integrated into the existing structure without major redesign.
4Ease of manufacture
If lubricant is applied once during manufacture, then the process is simple, but the lubrication is not continuous over time
Solution Approach 1:
The rolling element cage is pre-lubricated during manufacture with a precise amount of lubricant. This preliminary lubrication action ensures that the rolling elements receive the exact needed lubrication dose during assembly, preventing both insufficient and excessive lubrication while maintaining reliability throughout the product lifecycle.
Solution Approach 2:
The pull-out guide is designed with lubricant reservoirs and distribution channels that enable the system to automatically replenish lubricant to the rolling elements during operation. This self-service mechanism ensures continuous lubrication without external intervention, maintaining reliable lubrication retention while eliminating the need for manual reapplication.
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 provides optimal lubrication behavior over a wide temperature range, ensuring smooth operation from -40°C to over 400°C, reducing material intensity and maintaining lubrication throughout the guide's service life, while preventing dirt ingress and allowing for precise lubricant metering.
Implementation Method 1
Diffusion is based on the intrinsic thermal motion of particles. Particles can be atoms, molecules or charge carriers. In the present case it is about lubricant molecules. A macroscopic mass transport is caused by the fact that, in the case of non-uniform distribution, statistically more particles move from the area of high concentration to the area of lower concentration than vice versa.
Implementation Method 2
The material containing lubricant is a porous body made of sintered material or plastic, in which oil is stored as a lubricant. The stored oil can flow through capillaries or specially designed channels. Like a sponge, the body can absorb lubricant and then gradually release it again when the pull-out guide is actuated.
Data Source
Figure 1
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Figure 3
AI summary
A drawer slide (1) for furniture comprises a guide rail (2) mountable on a furniture carcass and at least one running rail (3, 4) mounted on the guide rail (2) so as to be movable via rolling elements (5), wherein the rolling elements (5) are mounted in a rolling element cage (10) which consists at least partially of a lubricant-containing material. The rolling element cage (10) has a plurality of pockets (13) in each of which a rolling element holder (11) made of lubricant-containing material with a rolling element (5) is inserted. This allows for precise metering of the lubricant over a long period of time.