Spring-Mounted Blade Assembly for Grass Cutting Robot Impact Management
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Solution Overview
Problem
Existing grass cutting mobile robots face challenges in safely navigating around obstacles without damaging their blades or actuators, as they lack effective mechanisms to manage impacts with non-mowable objects, leading to potential mechanical failure and inefficient cutting.
Innovation Solution
The mobile robot incorporates a blade assembly with spring-mounted blades that can rotate and move through angled slots within the housing, allowing them to retract and rise relative to the ground surface upon impact, reducing impulse force and enabling the robot to maneuver around objects, while a quick-release retention mechanism facilitates easy attachment and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the blades are rigidly mounted to rotate only about the drive axis, then the cutting performance is maintained, but the blades cannot withstand impact forces from non-mowable objects, leading to mechanical failure
Solution Approach 1:
The blade assembly allows the blades to dynamically adjust their orientation during operation. The blades are mounted to rotate about a mounting axis that is non-parallel to the drive axis, enabling them to tilt and absorb impact forces from obstacles while maintaining cutting functionality during normal operation.
Solution Approach 2:
The blade mounting mechanism is segmented into multiple rotational degrees of freedom. Each blade can rotate independently about the mounting axis, allowing individual blades to respond to impact forces separately rather than as a rigid unit, reducing stress transmission to the actuator.
2Reliability
If the blades are fixed in position, then the cutting efficiency is high, but the impulse force from impacts is transmitted directly to the actuator, causing potential damage
Solution Approach 1:
The blades are mounted on an angled axis relative to the drive axis, creating a dynamic mounting configuration. This allows the blades to tilt and move during impact events, distributing impulse forces over a longer duration and reducing peak forces transmitted to the actuator, while maintaining effective cutting positions during normal operation.
Solution Approach 2:
The angled mounting axis预先 configures the blade assembly to absorb impact forces through controlled movement. The geometry of the mounting arrangement is designed to convert sudden impact impulses into controlled rotational movements, cushioning the blow before it reaches the actuator.
3Reliability
If the blade assembly uses a complex retention mechanism for secure mounting, then the blades remain firmly attached during operation, but the attachment and detachment process becomes time-consuming
Solution Approach 1:
The retention mechanism is extracted and simplified to a quick-release system. The housing includes accessible push tabs that, when pressed, release the coupling latches to detach the blade assembly from the actuator. This extraction of the retention function into a simple, accessible mechanism reduces the time required for blade changes while maintaining secure attachment during operation.
Solution Approach 2:
The quick-release mechanism allows operators to easily attach and detach blade assemblies without requiring complex tools or procedures. The push-tab design enables intuitive operation where pressing the tabs automatically releases the coupling, making the blade change process self-explanatory and rapid.
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
This design reduces the risk of blade and actuator damage, enhances the robot's ability to navigate varied geometries, and improves cutting efficiency by distributing the force of impact over a longer duration, allowing for better control and reduced mechanical failure.
Implementation Method 1
The blade assembly includes two or more spring mounted blades, two or more springs, and a housing to hold the blades
Implementation Method 2
Each spring is configured to constrain movement of an associated one of the two or more blades
Implementation Method 3
a portion of each blade is configured to move within a corresponding slot towards the drive axis by rotating about the mounting axis of the blade
Data Source
AI summary
A grass cutting mobile robot includes a body and a blade assembly connected to the body and rotatable about a drive axis. The blade assembly includes blades, a housing to hold the blades, a coupling latch configured to lock the housing to a drive shaft of the mobile robot, and a spring that connects the blade to the coupling latch. The housing is configured for coupling to an actuator so that the housing is rotatable about a drive axis, and receives a shaft that connects the housing to the actuator. The shaft includes a groove or an undercut therein. The coupling latch is rotatable within the housing to move an engagement end towards, or away from the groove or undercut. The engagement end is positionable within the groove to lock the housing to the actuator.