Power Tool Guard Rotation Lock Mechanism
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Solution Overview
Problem
Existing hand-held power tool guards fail to securely position and lock in place, especially when subjected to high forces from rotating disk fragments, and do not comply with safety standards for angular positioning and fragment redirection.
Innovation Solution
The guard incorporates a rotation lock element interacting with a counter-element on the flange, creating a frictional and form-fit connection, allowing for secure angular positioning and redirection of fragments, with a design that includes a support surface on the hood body and a clamping device, enabling the guard to absorb large forces and maintain position without sliding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a guard is equipped with only a clamping device for fastening to the flange, then the guard can be easily installed and removed, but the guard cannot securely maintain its angular position and may slide during operation
Solution Approach 1:
The connection between guard and flange is segmented into two independent functional elements: a clamping device for radial fastening and a rotation lock element for angular positioning. This segmentation allows each element to perform its specific function optimally without interfering with the other, resolving the contradiction between ease of installation and angular position stability.
Solution Approach 2:
A rotation lock element is introduced as an intermediary component between the guard and the flange. This element mediates the angular positioning function, working in conjunction with the clamping device to achieve both easy installation and stable angular positioning. The rotation lock element translates the clamping force into precise angular positioning without requiring complex mechanisms.
2Device complexity
If the guard relies solely on frictional connection from the clamping device, then the structure remains simple, but the guard cannot absorb large forces from rotating disk fragments
Solution Approach 1:
The connection structure is segmented into a clamping function and a locking function, where the rotation lock element provides additional force absorption capability through form-fit engagement. This segmentation allows the system to handle large forces from disk fragments while maintaining overall structural simplicity.
Solution Approach 2:
The connection system combines two different connection mechanisms: frictional connection from the clamping device and form-fit connection from the rotation lock element. This composite connection approach enables the guard to absorb large forces while keeping the overall device complexity low, as both mechanisms use simple geometric features.
3Ease of manufacture
If the guard is designed without a rotation lock element, then the manufacturing process remains simple, but the guard cannot comply with safety standards for fragment redirection
Solution Approach 1:
The safety function is segmented into a dedicated rotation lock element that works together with the clamping device. This segmentation allows the safety standard compliance to be achieved through a simple geometric feature that can be easily manufactured, without complicating the overall manufacturing process.
Solution Approach 2:
The rotation lock element changes the angular position parameter of the guard relative to the flange, creating specific latching positions that ensure proper orientation for fragment redirection. This parameter change is achieved through simple geometric engagement that can be manufactured using conventional processes, maintaining ease of manufacture while ensuring safety standard compliance.
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 ensures the guard remains securely positioned, absorbing extreme forces and redirecting fragments safely away from the user, meeting safety standards by allowing rotation up to 90° and maintaining the desired position through latching profiles.
Implementation Method 1
The clamping produces a frictional connection between the flange and the guard, which fixes the guard in position and prevents it from rotating
Implementation Method 2
Screw connections or clamping levers are typically used to clamp the clamping element. The clamping produces a frictional connection between the flange and the guard
Data Source
AI summary
The invention relates to a protective hood for a hand tool, in particular for an electrical hand tool which has a support area for the attachment of a flange of the hand tool, and with a clamping device for fastening the protective hood to the flange as well as an anti-twist device to secure the angle position of the protective hood relative to the hand tool. It is provided that the support area (9) has at least one anti-twist device element (18) working in conjunction with at least one anti-twist device mating element (47) of the flange (34).