Hand-Held Milling Machine Transverse Drive Eccentric Pendulum

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing hand-held milling machines experience significant reaction forces during the milling of elongated holes, leading to potential 'tearing' and unclean holes, especially when using dowels with elongated cross-sections, as the machine must be manually moved back and forth, causing uneven milling paths.

Innovation Solution

The milling machine incorporates a transverse drive device with an eccentric mechanism and adjustable pendulum axles, allowing for a controlled, adjustable amplitude of the pivoting movement of the output shaft, which reduces manual intervention and maintains a consistent feed movement, thereby minimizing reaction forces and ensuring cleaner elongated holes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the milling machine is moved back and forth manually during milling, then the slot can be milled, but reaction forces increase causing the machine to jerk and produce unclean slots

Engineering Contradiction:
Improveslot cleanlinessVSAvoidreaction forces
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The patent applies dynamics by making the pendulum axis position adjustable during operation. The actuating element allows the user to change the pendulum axis position along the pendulum lever, which dynamically changes the amplitude of the reciprocating pivoting movement of the output shaft. This dynamic adjustment capability enables optimization of the milling process for different slot lengths and material conditions, reducing reaction forces and preventing machine jerking while maintaining clean slot production.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the amplitude of reciprocating pivoting motion is adjusted by pivoting the pendulum axis on an adjusting lever, then slot length can be varied, but the structure becomes complex and prone to malfunctions

Engineering Contradiction:
Improveslot length adjustmentVSAvoidadjustment mechanism structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements parameter changes by providing multiple discrete pendulum axis positions along the pendulum lever. Instead of continuous adjustment, the actuating element selects from several predetermined positions, each corresponding to a specific amplitude of reciprocating motion. This discretized approach achieves versatile slot length adjustment while significantly simplifying the mechanical structure and reducing the risk of malfunctions compared to continuous adjustment mechanisms.

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 solution allows for a quieter and more precise milling process by maintaining an uninterrupted feed movement, reducing the amplitude of reaction forces and ensuring the milling tool moves in a consistent zigzag path, resulting in cleaner and more accurate elongated holes.

Implementation Method 1

a transverse drive device, which includes an eccentric device controlling the pivoting movement and driven by the drive motor

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Implementation Method 2

with a pendulum lever mounted to pivot about a pendulum axis, which is in pivoting connection with the output shaft

Methodology Applied
Scientific EffectPendulum motion: Pendulum

Data Source

PatentEP1757415B1Milling machine
Publication Date: 2009.01.21 FESTOOL GMBH
  • EP1757415B1 patent drawingFigure 1
  • EP1757415B1 patent drawingFigure 2~4
  • EP1757415B1 patent drawingFigure 3~6

AI summary

A swing lever (57) is provided with multiple shaft bodies (71,72,73) with intermeshing sprocket wheels (78,79,80). One of the shaft bodies (72) is coupled to an operating member (65). The shaft bodies and their operating parts (81,82,83) rotate relative to each other so that when the operating member is in different rotational positions, one respective other operating part forms the swing axel (58).