Telescopic rail

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Solution Overview

Problem

Conventional telescopic rails require complex design to accommodate movable rolling element cages, increasing design requirements and friction during displacement movements.

Innovation Solution

Fixing the rolling element cage to the first rail element allows rolling elements to perform a sliding movement relative to the first rail and a rolling or sliding movement relative to the second rail, reducing overall friction and simplifying design requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the rolling element cage is made movable relative to both rail elements to ensure even distribution of rolling elements, then the rolling elements can be evenly distributed, but the design complexity increases significantly

Engineering Contradiction:
Improveeven distribution of rolling elementsVSAvoiddesign requirements for rail elements and rolling element cage
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of making the rolling element cage movable relative to both rail elements as in conventional designs, the patent fixes the rolling element cage to the first rail element. This inversion of the conventional approach eliminates the complexity of ensuring relative movement while still achieving functional requirements through sliding movement of rolling elements on the first rail element's running surface.

Inventive Principle:
Principle #13The other way round (Inversion)

2Object-affected harmful factors

If rolling elements are arranged to roll against each other on rail surfaces to reduce friction, then displacement movement friction is reduced, but the rolling element cage must be movable relative to both rail elements simultaneously

Engineering Contradiction:
Improvefriction during displacement movementVSAvoiddesign requirements for relative movement
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies different movement modes to different locations: rolling elements perform sliding movement on the first rail element's running surface and rolling movement on the second rail element's running surface. This local differentiation allows friction reduction through rolling where applicable while simplifying the overall design by fixing the cage to the first rail element.

Inventive Principle:
Principle #3Local quality

3Device complexity

If the rolling element cage is fixed to the first rail element, then design requirements are reduced, but rolling elements must slide on the first rail element's running surface

Engineering Contradiction:
Improvedesign requirements for rail elements and rolling element cageVSAvoidfriction between rolling elements and first rail element
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent accepts sliding movement (higher friction) on the first rail element's running surface in exchange for design simplification, while compensating by implementing rolling movement on the second rail element's running surface. This local differentiation of movement modes balances the trade-off between design complexity and friction reduction.

Inventive Principle:
Principle #3Local quality

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 configuration reduces overall friction during displacement and simplifies the design by eliminating the need for relative movement of the rolling element cage with respect to both rail elements, while allowing for effective lubrication and integration of braking mechanisms.

Implementation Method 1

the roller bodies perform a sliding movement relative to the running surfaces of the first rail element and the rolling bodies perform a sliding movement relative to the running surfaces of the second rail element. Depending on the level of friction between the rolling elements and the rolling element cage and between the rolling elements and the running surfaces of the first rail element, the rolling elements will slide relative to the running surfaces of the second rail element or will roll on the running surfaces of the second rail element.

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3724526B1Telescopic rail
Publication Date: 2021.09.15 ACCURIDE INTERNATIONAL GMBH
  • EP3724526B1 patent drawingFigure 1
  • EP3724526B1 patent drawingFigure 2
  • EP3724526B1 patent drawingFigure 3

AI summary

The invention relates to a telescopic rail comprising a first rail element with two running surfaces, a second rail element with two running surfaces, at least one rolling element cage for positioning a plurality of rolling elements, and a plurality of rolling elements which are received on the rolling element cage. Sections of the rolling element cage together with the rolling elements are arranged between the running surfaces of the first and second rail element such that the first rail element and the second rail element can be moved linearly relative to each other in a pull-out direction. The rolling element cage fixes the position of each rolling element in the pull-out direction relative to the rolling element cage. Such telescopic rails have the disadvantage that the rail elements and the rolling element cages must all be designed to be movable relative to one another. Therefore, the invention proposes a telescopic rail in which the rolling element cage is secured to the first rail element such that the rolling elements carry out a sliding movement relative to the running surfaces of the first rail element, and the rolling elements carry out a sliding movement relative to the running surfaces of the second rail element or roll on the running surfaces of the second rail element.