Router Handle With Rotary Lock And Deflection Gear

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Solution Overview

Problem

Existing hand-held machine tools, such as routers, are uncomfortable and unsafe to hold due to the design of the rotary handle, which can lead to unintentional actuation and loss of control during operation.

Innovation Solution

A handle is fixed on the machine part and designed to be gripped parallel or inclined to the longitudinal direction, with a rotary handle at the end that is easily accessible for thumb operation, connected to a deflection gear for precise control of the locking mechanism, separating the functions of holding and locking and ensuring secure grip without accidental twisting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the handle and rotary handle are formed by a single part, then the device complexity is reduced, but the ease of operation deteriorates and reliability worsens due to unintentional actuation

Engineering Contradiction:
Improvestructure complexityVSAvoidhandling comfort
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The handle is divided into two separate functional components: a fixed handle for holding the machine tool and a rotary handle for actuating the locking mechanism. This segmentation allows the user to grip the fixed handle securely without risk of unintentional actuation, while the separate rotary handle provides dedicated control for locking and loosening operations.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the rotary handle is arranged on the end area of the tie rod, then the device complexity is reduced, but reliability worsens due to accidental twisting during movement

Engineering Contradiction:
Improvestructure complexityVSAvoidcontrol safety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The rotary handle is extracted from the tie rod structure and repositioned to be arranged on the fixed handle. This separation removes the hazard of accidental twisting from the tie rod area, while the rotary handle remains easily accessible on the handle for intentional actuation only.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If the handle runs parallel or inclined to the longitudinal direction, then the ease of operation improves for ergonomic gripping, but the device complexity increases due to deflection gear requirements

Engineering Contradiction:
Improvegripping comfortVSAvoidmechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

A deflection gear acts as an intermediary mechanism between the rotary handle and the tie rod. This intermediary allows the rotary handle to be positioned ergonomically on the handle while still transmitting the actuating force to the tie rod, resolving the conflict between ergonomic positioning and mechanical connectivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP1995028B1Machine tool, in particular router
Publication Date: 2014.01.15 FESTOOL GMBH
  • EP1995028B1 patent drawingFigure 1
  • EP1995028B1 patent drawingFigure 2
  • EP1995028B1 patent drawingFigure 3

AI summary

The tool has a handle (7) fixedly arranged at a machine part (5) and formed by a hand grip (9) that is enclosed by an operator. The hand grip runs parallel or inclined to a columned longitudinal direction (6) such that a rotary handle (14) of a locking device is arranged at a free end of the hand grip. The rotary handle is rotatable around a rotation axis line (15), is in impellent connection with a tie rod (18) by a reverse gear (20) e.g. bevel gear, and rotates the tie rod.