Eccentric Disc Sanders for Uniform Workpiece Grinding

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Solution Overview

Problem

Existing through-feed grinding machines using disc sanders struggle to cover the entire width of flat workpieces efficiently due to the need for multiple sanders arranged at a distance, leading to unsatisfactory grinding results and high costs, as well as potential damage from centrifugal force and inhomogeneous sanding patterns.

Innovation Solution

A through-feed grinding machine design where adjacent disc sanders are attached eccentrically to their spindles, allowing their cutting circles to overlap and be driven by a single motor, eliminating the need for oscillating movements and additional rows, and incorporating an additional staggered row of grinding tools for comprehensive coverage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple disc sanders are arranged close together, then the workpiece can be ground more comprehensively, but the abrasive flaps collide and damage each other due to centrifugal force

Engineering Contradiction:
Improvegrinding coverageVSAvoidabrasive flap integrity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The disc sanders are mounted on an oscillating mechanism that moves them transversely during operation. This dynamic positioning allows the sanders to cover a wider area without requiring permanent close spacing, preventing abrasive flap collision while maintaining comprehensive grinding coverage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention adds a transverse oscillation dimension to the traditional linear arrangement of disc sanders. By oscillating the sanders back and forth perpendicular to the feed direction, the system achieves broader coverage without increasing the number of sanders or reducing spacing, thus avoiding centrifugal force conflicts.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If disc sanders are arranged in two rows or with oscillating movement, then the workpiece surface is better covered, but the device becomes very expensive and complex

Engineering Contradiction:
Improvesanding pattern uniformityVSAvoidnumber of rotating parts
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

A single oscillating mechanism serves multiple functions: it positions all disc sanders simultaneously, creates the sanding pattern, and replaces the need for multiple independent positioning systems. This multi-functionality reduces overall device complexity while achieving uniform sanding coverage.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention combines multiple disc sanders into a single oscillating assembly rather than using separate mounting mechanisms for each sander. This merging of functions reduces the number of individual components and simplifies the overall structure while maintaining comprehensive surface coverage.

Inventive Principle:
Principle #5Merging (Combining)

3Area of stationary object

If oscillating movement is used to improve coverage, then the grinding result suffers because the relative speed approaches zero in the oscillation area

Engineering Contradiction:
Improveprocessed areaVSAvoidgrinding quality
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The oscillating mechanism performs periodic back-and-forth movements that continuously bring fresh abrasive flaps into contact with the workpiece surface. This periodic action ensures that even though the oscillation speed is low, the continuous renewal of abrasive contact maintains grinding quality while expanding processed area.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses controlled oscillation dynamics where the amplitude and frequency are optimized to maintain sufficient relative speed between abrasive and workpiece. The oscillating motion creates dynamic grinding paths that cover more area without reducing grinding effectiveness, as the motion is designed to maintain productive contact speeds.

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 ensures uniform grinding over the entire width of the workpiece with improved results and reduced manufacturing costs, avoiding collisions and ensuring every area is ground with consistent intensity.

Implementation Method 1

disc sanders (20) attached eccentrically to said spindles (18) and with said spindles (18) and disc sanders (20) rotating around a vertical axis (24)

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 2

disc sanders (20) attached eccentrically to said spindles (18)... by attaching the disk sander off-center on the spindle, the circle of motion of the disk sander can be enlarged

Methodology Applied
Scientific EffectEccentric rotation: Eccentric

Implementation Method 3

adjacent grinding tools are driven by a belt, in particular a toothed belt

Methodology Applied
Scientific EffectBelt friction: Friction

Data Source

PatentEP1743737B1Flow path sanding machine for processing a plane workpiece surface
Publication Date: 2009.01.28 JAKOB LOWER INH VON SCHUMANN
  • EP1743737B1 patent drawingFigure 1
  • EP1743737B1 patent drawingFigure 2
  • EP1743737B1 patent drawingFigure 3

AI summary

The grinding machine has at least two rotating grinding tool is, rotating about a vertical axis (24), a spindle (18) rotating round the same axis, and the plate grinder (20) on the spindle. The grinding tools are arranged in a row transversely to the feed direction of the workpiece (10, 12). At least one plate grinder is fitted eccentrically to its spindle.