Air Cushion Table With Variable Duct Geometry For Lightweight Workpiece Support

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Solution Overview

Problem

Air cushion tables in woodworking machines struggle to reliably support workpieces with low surface load, as they require valve actuation to trigger the air cushion, which can be difficult for small or lightweight pieces and may lead to contamination and blockage issues.

Innovation Solution

The air cushion table design features air outlet ducts with a constant lower section and a wider upper section, eliminating the need for pin-actuated valves by increasing the air bearing surface without expanding the air outlet channel flow, allowing for more outlets and reduced power consumption, while minimizing clogging risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pin-actuated valves are used in air outlet openings, then contamination and blockage of air-conducting areas can be prevented, but workpieces with low surface load cannot reliably open the valve and trigger the air cushion

Engineering Contradiction:
Improveair cushion activationVSAvoidvalve actuation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention extracts and eliminates the pin-actuated valve mechanism from the air outlet openings. By removing this mechanical activation component, the system allows workpieces of any weight to directly trigger the air cushion through their presence alone, eliminating the activation problem for lightweight pieces while maintaining contamination protection through the duct design itself

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The air outlet duct with its specific geometry (narrow lower section, wider upper section) serves as an intermediary structure that replaces the valve mechanism. It mediates between the compressed air supply and the workpiece by creating a flow resistance that generates sufficient air pressure to lift even lightweight workpieces without requiring mechanical valve actuation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Area of stationary object

If the number of air outlet openings is increased, then the air bearing surface is increased and low surface load workpieces can be supported, but the installation effort and costs increase

Engineering Contradiction:
Improveair bearing surfaceVSAvoidinstallation effort
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The invention segments the air outlet system into multiple individual air outlet ducts, each with its own optimized geometry. This segmentation allows each duct to independently generate sufficient air pressure to support workpieces, enabling the system to handle lightweight pieces effectively while the modular nature of segmented ducts simplifies installation compared to alternative designs

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The air outlet ducts exhibit local quality variations along their length - a narrow lower section for flow control and a wider upper section for pressure generation. This localized geometric optimization allows each duct to function effectively as a standalone air bearing element, enabling increased number of outlets without proportionally increasing complexity

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If the flow cross section of air outlet channels is expanded to increase air volume flow, then more air can be supplied to support workpieces, but the installation effort and power consumption increase

Engineering Contradiction:
Improveair volume flowVSAvoidpower consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by stationary object

Solution Approach 1:

The invention changes the geometric parameters of the air outlet ducts by creating a non-uniform cross-section along the flow direction. The transition from a narrow lower section to a wider upper section optimizes the air flow characteristics, generating sufficient air volume and pressure to support workpieces without requiring a proportional increase in overall flow cross-section or power consumption

Inventive Principle:
Principle #35Parameter changes

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 enables the support of workpieces with low surface load without valve actuation, reduces installation effort and costs, and minimizes the risk of surface damage and clogging, while maintaining load capacity and efficient airflow.

Implementation Method 1

a compressed air source, which provides a volume flow of preferably compressed air

Methodology Applied
Scientific EffectCompressed air:

Implementation Method 2

The workpiece then floats on an air cushion and can easily be moved horizontally above the support surface

Methodology Applied
Scientific EffectAir cushion: Air Lubrication

Implementation Method 3

A first, lower section has a constant cross section and represents a defined flow resistance

Methodology Applied
Scientific EffectFlow resistance:

Data Source

PatentEP2251127B1Wood processing machine with air cushion table
Publication Date: 2015.04.08 WILHELM ALTENDORF GMBH & CO KG
  • EP2251127B1 patent drawingFigure 1
  • EP2251127B1 patent drawingFigure 2
  • EP2251127B1 patent drawingFigure 3

AI summary

The airbearing table has an air supply opening, an upper bearing surface (11) with multiple air outlet openings, and an air distributor for connecting the air supply opening with the multiple air outlet openings (20). The air distributor is connected with each air outlet opening over an air outlet channel which extends from the air distributor to the air outlet openings and which has a section lying below the upper bearing surface.