Pivotable Transverse Stop for Dowel Milling Cutter Jamming

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Solution Overview

Problem

Previous cross stop devices in hand-held power tools are prone to jamming due to dirt accumulation and are difficult to clean, especially in their longitudinally adjustable holes.

Innovation Solution

A pivotable transverse stop device is designed with a pivoting mechanism that allows easy cleaning and is less prone to soiling, featuring a transverse stop pawl that can swing out of the front stop surface, with spring-loaded and lockable components for precise positioning and easy exchange, and an anti-loss device to prevent misplacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a longitudinally adjustable transverse stop device is used, then the transverse distance can be adjusted, but the device is prone to jamming due to dirt accumulation in the adjustment holes

Engineering Contradiction:
Improveadjustability of transverse distanceVSAvoidjamming resistance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The transverse stop device is changed from a longitudinally adjustable mechanism to a pivotable mechanism. The stop device can swing between a retracted position (where it is aligned with or behind the front stop surface) and a protruding position (where it defines the transverse distance). This dynamic pivoting motion allows dirt to be easily shaken out and prevents accumulation in fixed adjustment holes, thereby improving reliability while maintaining adjustability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Instead of adjusting the stop device longitudinally along the axis of the tool, the invention inverts the adjustment mechanism by allowing the stop device to pivot sideways. The adjustment is achieved through rotational movement around a pivot point rather than linear movement through holes, which eliminates the jamming problem associated with dirty holes.

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

2Ease of operation

If a pivoting transverse stop device is used, then cleaning is easier and jamming is reduced, but additional components like pivot bearings and locking mechanisms are required

Engineering Contradiction:
Improvecleaning easeVSAvoidnumber of components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The pivot bearing is integrated into the housing structure, and the locking mechanism is incorporated as part of the existing stop device assembly. The pivot axis is formed by a bearing element that is nested within the housing, eliminating the need for separate external mounting structures. This nesting approach reduces overall device complexity while enabling the pivoting functionality.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Manufacturing precision

If the transverse stop device protrudes in front of the front stop surface, then it can define transverse distances, but it may get into recesses in the workpiece

Engineering Contradiction:
Improvetransverse distance accuracyVSAvoidrisk of getting stuck in recesses
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The stop device dynamically changes its position relative to the front stop surface. In the protruding position, it extends beyond the front surface to define the transverse distance for accurate positioning. When not in use or when approaching a workpiece with recesses, it can be retracted to align with or behind the front surface, eliminating the risk of getting stuck in recesses.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The pivoting mechanism allows the operator to anticipate potential problems by retracting the stop device before contacting workpieces with recesses. The ability to switch between protruding and retracted positions provides preliminary protection against the harmful effect of getting stuck, allowing the operator to adapt to different workpiece geometries.

Inventive Principle:
Principle #9Preliminary anti-action

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

The solution reduces the risk of jamming and maintains dimensional accuracy by allowing easy cleaning and precise adjustment of transverse distances, ensuring smooth operation and adaptability to different dimensions.

Implementation Method 1

The at least one transverse stop device is expediently spring-loaded into the stop position. The cross stop device then pivots automatically into the stop position.

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP2090411B1Hand tool machine
Publication Date: 2010.08.18 FESTOOL GMBH
  • EP2090411B1 patent drawingFigure 1~3
  • EP2090411B1 patent drawingFigure 2

AI summary

The tool (10) i.e. dowel milling cutter (11), has cross-aligning stop devices (25a, 25b) with cross-aligning stops (26) for lateral contact at a work piece transverse side (27) to determine a transverse distance (48) between the transverse side and a recess (31) in a work piece (24). The devices are moved between stop and resting positions, in which the devices preside and do not preside over a front stop surface (20), respectively. The devices are mounted at a pivoting bearing (47) with respect to the surface in a displaceable manner.