Angle Grinder Dust Shroud Cam Hinge Assembly

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Solution Overview

Problem

Conventional dust shrouds for angle grinders often leave parts of the grinding wheel exposed, failing to provide full protection and user safety, as they only partially cover the arcural portion, and lack a reliable mechanism for easily opening and closing the shroud door.

Innovation Solution

A hinge assembly with a cam/spring mechanism is used to securely attach a door member to a main structure, allowing the door to be biased into open or closed positions, ensuring full enclosure of the grinding wheel when closed and partial exposure when open, utilizing a compression spring and cam surfaces for axial movement and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a conventional dust shroud is used, then the structure is simple, but the grinding wheel is not fully protected and user safety is compromised

Engineering Contradiction:
Improveexposure to grinding wheelVSAvoidshroud structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The shroud is divided into a main body and a separate door member that can be opened and closed. This segmentation allows the grinding wheel to be fully enclosed when the door is closed, while still maintaining a relatively simple overall structure that can be opened for wheel changes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A hinge assembly with cam surfaces acts as an intermediary mechanism between the door member and main shroud body. This intermediary provides reliable opening and closing functionality while maintaining structural simplicity through standardized hinge components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a reliable opening and closing mechanism is added to the shroud, then user safety and operational convenience are improved, but the device complexity increases

Engineering Contradiction:
Improvedoor opening and closingVSAvoidhinge assembly
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The hinge assembly incorporates cam surfaces that dynamically adjust the door member's position during opening and closing operations. The cam surfaces provide automatic positioning and biasing forces that ease operation while the modular hinge design keeps the overall complexity manageable.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring-loaded cam mechanism provides automatic biasing forces that assist the user in opening and closing the door. The spring automatically returns the door to its proper position, reducing the manual effort required and improving ease of operation without requiring complex control systems.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If a cam/spring mechanism is used for the hinge assembly, then the door can be easily biased into open or closed positions, but the manufacturing complexity increases

Engineering Contradiction:
Improvedoor positioningVSAvoidhinge assembly
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The hinge assembly is segmented into separate components including the first hinge member, second hinge member, cam surfaces, and spring. This segmentation allows each component to be manufactured independently using standard machining processes, then assembled together, reducing overall manufacturing complexity despite the sophisticated functionality.

Inventive Principle:
Principle #1Segmentation

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 hinge assembly ensures the shroud door can be easily opened and closed, providing complete protection of the grinding wheel and user safety by fully enclosing the wheel when needed and allowing controlled exposure, enhancing user safety and operational convenience.

Implementation Method 1

a compression spring having two ends respectively engaging the first and the second hinge members. In an embodiment, the compression spring biases the first and second cam surfaces to engage one another

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

a first cam surface defined by a surface of the first hinge member and a second cam surface defined by a surface of the second hinge member and correspondingly engaging the first cam surface. In an embodiment, the first and second cam surfaces cause the second hinge member to move axially with respect to the first hinge member as the door member is rotated

Methodology Applied
Scientific EffectCam: Cam

Data Source

PatentEP2799184B1Angle grinder dust shroud
Publication Date: 2016.03.23 BLACK & DECKER CORP
  • EP2799184B1 patent drawingFigure 1
  • EP2799184B1 patent drawingFigure 2~3
  • EP2799184B1 patent drawingFigure 4~5

AI summary

A hinge assembly for attaching a door member to a main structure is provided. The hinge assembly, in an embodiment, includes a first hinge member securely attached to one of the door member or the main structure; a second hinge member securely attached to the other of the door member or the main structure and rotatably engaging the first hinge member; and a cam/spring assembly configured to bias the door member into an open or a closed position with respect to the main structure.