Interchangeable Blade Assembly with Movable Cover

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Solution Overview

Problem

Existing power tools with interchangeable cutting or trimming elements often require users to handle greasy internal components and moving parts during blade changes, leading to exposure and potential contamination, and they suffer from unnecessary part duplication and increased storage space due to integrated housing elements.

Innovation Solution

A power tool design featuring a tool housing with a movable cover that allows for tool-less attachment and detachment of blade assemblies, using a snap-fit mechanism with flexible members and guide elements to protect users from internal components and simplify blade changes, while ensuring secure retention and alignment with the drive assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If users manually handle blade assemblies during changes, then blade replacement can be performed, but users are exposed to grease and internal components leading to contamination risk

Engineering Contradiction:
Improveblade replacement processVSAvoiduser exposure to grease and internal components
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a removable cover assembly as an intermediary component between the user and the drive assembly. This cover assembly includes a cover body that can be removed from the tool housing, allowing users to access and replace blade assemblies without directly exposing their hands to grease and internal components. The cover assembly acts as a protective barrier that mediates the interaction between the user and the contaminated internal parts.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If integrated housing elements are used for each blade set, then blade retention is achieved, but part duplication increases and storage space is consumed

Engineering Contradiction:
Improveblade retentionVSAvoidpart duplication
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a universal cover assembly that can accommodate multiple different blade assemblies through a standardized interface. Instead of having dedicated housing elements for each blade type, the single cover assembly serves multiple functions: it retains various blade assemblies, protects the drive assembly, and provides a unified removal mechanism. This multi-functional design eliminates part duplication while maintaining reliable blade retention.

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

3Adaptability or versatility

If blade assemblies are completely detached from the tool, then blade interchangeability is achieved, but user protection from moving parts and grease is lost

Engineering Contradiction:
Improveblade interchangeabilityVSAvoidexposure to moving parts and grease
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the tool into distinct functional components: the tool housing containing the drive assembly, the removable cover assembly, and the interchangeable blade assemblies. This segmentation allows the cover assembly to be removed for blade changes while maintaining a protective barrier. The modular design enables blade interchangeability while the cover assembly continues to protect users from moving parts and grease during the replacement process.

Inventive Principle:
Principle #1Segmentation

4Manufacturing precision

If manual coupling of blade assembly to drive assembly is required, then direct connection is achieved, but operation complexity and time increase

Engineering Contradiction:
Improveblade alignment with drive assemblyVSAvoidblade replacement time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent implements a self-aligning mechanism where the cover assembly includes guide features that automatically align the blade assembly with the drive assembly during insertion. The blade assembly is designed to self-position within the cover assembly, eliminating the need for manual alignment by the user. When the cover assembly is reattached to the tool housing, the blade assembly is automatically positioned correctly, reducing replacement time while maintaining precision.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2286659B1Power tool having an interchangeable blade assembly and method for interchanging the blade assembly
Publication Date: 2018.05.30 ROBERT BOSCH GMBH
  • EP2286659B1 patent drawingFigure 1
  • EP2286659B1 patent drawingFigure 2
  • EP2286659B1 patent drawingFigure 3

AI summary

A power tool (10) having a housing (32), a blade assembly (12), a drive assembly within the housing (32) for driving the blade assembly (12), and a cover (38) that is coupled to the power tool (10) and is movable between at least two positions, wherein the blade assembly (12) is fixedly retained by the power tool (10) when the cover (38) is in a first position and is detachable from the power tool (10) when the cover (38) is in a second position and wherein the cover (38) has tool-less means (60,62,74) for coupling the blade assembly (12) to the cover (38) when the cover (38) is in the second position.