Cutting Length Limiting Device for Portable Tools

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Solution Overview

Problem

Existing cutting length limiting devices for portable machine tools lack precision in maintaining a desired cutting length, especially when the cutting depth changes, and often require visual control, which can be inconvenient and imprecise.

Innovation Solution

A cutting length limiting device with a setting unit that adjusts the position of a stop element based on a set cutting depth, using a coupling element with a positive or non-positive connection to a guide unit, and includes a clamping unit for secure fixation, allowing for precise adjustment of the cutting length without visual control through tactile and acoustic feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a stop element is attached to a positive guide unit to limit cutting length, then the cutting length can be limited, but the precision in maintaining the desired cutting length deteriorates when cutting depth changes

Engineering Contradiction:
Improvecutting length precisionVSAvoidadaptability to cutting depth changes
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The stop element's position is made dynamically adjustable through the setting unit, which allows the operator to reposition the stop element based on the desired cutting depth. This dynamic adjustment capability ensures that the cutting length precision is maintained across different cutting depths, resolving the contradiction between precision and adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The setting unit enables changing the positional parameter of the stop element to correspond to different cutting depths. By adjusting the stop element's position parameter according to the cutting depth parameter, the system maintains precise cutting length control while adapting to various cutting depth requirements.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If visual control is used to maintain desired cutting length, then the cutting length can be monitored, but the convenience and precision of operation deteriorate

Engineering Contradiction:
Improvecutting length measurementVSAvoidoperational convenience
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The stop element provides tactile feedback to the operator when the cutting reaches the predetermined length. This feedback mechanism eliminates the need for continuous visual monitoring, allowing the operator to maintain precise cutting length control through tactile sensation alone, thereby improving ease of operation while preserving measurement precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The stop element automatically signals the operator when the cutting length is reached, without requiring active visual inspection. The system serves itself by providing inherent tactile feedback, freeing the operator from the burden of visual control and improving operational convenience while maintaining precision.

Inventive Principle:
Principle #25Self-service

3Device complexity

If the stop element position is fixed, then the device structure is simple, but the ability to adjust cutting length based on cutting depth changes deteriorates

Engineering Contradiction:
Improvedevice structureVSAvoidadjustability to cutting depth
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The setting unit introduces a controlled dynamic element that allows the stop element position to be adjusted according to cutting depth requirements. This minimal dynamic component enables adaptability without significantly increasing overall device complexity, as the adjustment mechanism is integrated into the existing stop unit structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The setting unit serves multiple functions: it adjusts the stop element position, corresponds to different cutting depths, and maintains cutting length precision. By consolidating these functions into a single integrated unit, the device achieves high adaptability without proportionally increasing complexity, as the same structural elements perform multiple roles.

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

Data Source

PatentEP2780140B1Device for limiting the length of a cut
Publication Date: 2015.07.29 ROBERT BOSCH GMBH
  • EP2780140B1 patent drawingFigure 1
  • EP2780140B1 patent drawingFigure 2
  • EP2780140B1 patent drawingFigure 3

AI summary

The invention relates to a device for limiting the length of a cut, to be used in portable machine tools (12), and comprising at least one stop unit (14) that has at least one stop element (18) which can be fixed to a force-feed unit (16). It is suggested that at least one adjustment unit (20) is provided to adjust a stop element (18) position which corresponds to a desired length of a cut, in accordance with a cut depth (T) that has been set.