Quick-Release Lawnmower Blade Assembly for Safe Tool-Free Removal
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Solution Overview
Problem
Existing lawnmower blade removal systems require significant effort and pose a risk of bodily harm due to the use of threaded fasteners and high torque loads, making it difficult and unsafe to replace or sharpen blades.
Innovation Solution
A quick release blade assembly with an actuatable member that allows for rapid coupling and uncoupling of blades from a drive shaft using an actuatable member that displaces in the radial direction, eliminating the need for tools and reducing the risk of injury.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If threaded fasteners with high torque loads are used to secure the blade, then the blade connection strength is improved, but the ease of operation deteriorates due to the considerable effort required for removal and the risk of bodily harm
Solution Approach 1:
The fastening system is segmented into multiple independent locking elements (first locking element and second locking element) that can be independently engaged and disengaged. This allows the blade to be securely fastened through multiple locking points while enabling tool-free removal by simply disengaging these segmented locking elements, thus resolving the contradiction between strong connection and easy removal.
Solution Approach 2:
The locking elements are designed to be movable between engaged and disengaged states. The first locking element can rotate between locked and unlocked positions, and the second locking element can be pressed to disengage. This dynamic design allows the system to transition from a high-strength locked state to an easily opened state, eliminating the need for tools and reducing operator effort.
2Strength
If threaded fasteners with high torque loads are used to secure the blade, then the blade connection strength is improved, but the device complexity increases due to the need for specialized tools and thread lock materials
Solution Approach 1:
The complex threaded fastening system with nuts, washers, and thread lock materials is extracted and replaced with a simplified quick-release mechanism. The locking elements directly engage with the drive shaft without requiring separate fasteners, eliminating the need for wrenches and thread lock chemicals, thus reducing device complexity while maintaining connection strength through the locking elements' engagement design.
Solution Approach 2:
The locking elements are designed to be self-contained and self-operating. The first locking element automatically engages with the drive shaft when the blade is mounted, and can be manually released by rotating it. The second locking element similarly engages and can be disengaged by pressing. This self-service design eliminates the need for external tools and complex fastening procedures, reducing overall system complexity.
3Reliability
If threaded fasteners are used to secure the blade, then the reliability of blade attachment is improved, but the loss of time increases due to the considerable effort and time required for blade removal
Solution Approach 1:
The locking elements are pre-positioned and spring-loaded to automatically engage with the drive shaft when the blade is mounted. The first locking element rotates into the locked position, and the second locking element is pressed into engagement, preparing the system for secure operation. This preliminary action ensures reliable attachment while enabling rapid removal by simply reversing the engagement motion, thus reducing the time loss for blade replacement.
4Strength
If threaded fasteners with high torque loads are used, then the blade connection strength is improved, but the object-generated harmful factors increase due to the risk of operator injury from slipping or sharp objects
Solution Approach 1:
The traditional mechanical fastening system using high-torque threaded fasteners and wrenches is replaced with a locking element system that uses rotational engagement and spring pressure. This substitution eliminates the need for high-torque operations with wrenches that could cause slipping and injury, while maintaining secure blade attachment through the locking elements' engagement with the drive shaft, thus reducing operator injury risk.
Data Source
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AI summary
Quick release blade assemblies for a power tool are provided. A lawnmower includes a base including an engagement interface; a retainer having a locking component; a blade disposed between the base and the retainer; and an actuatable member including an engagement member, the engagement member being selectively displaceable with respect to the engagement interface between a locked configuration and an unlocked configuration when the actuatable member is translated in a direction parallel with the axis of rotation, wherein the engagement member is configured to interface with the locking component to selectively couple the blade to the drive shaft when the engagement member is in the locked configuration.