Movable Blade Guard for Robot Lawnmower Safety
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Solution Overview
Problem
Robot lawnmowers pose a risk of user contact with blades during manual interaction, as the blades are positioned close to the lateral sides, increasing the likelihood of accidental contact and reducing cutting efficiency due to wider spacing.
Innovation Solution
The implementation of movable blade guards mounted to the chassis and bumper, which rotate inwardly and outwardly to prevent user contact with the blades and adjust position to avoid objects, allowing the blades to be positioned closer to the lateral sides without increasing the risk of user interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If blades are positioned closer to lateral sides, then cutting efficiency is improved, but user safety deteriorates due to increased risk of contact
Solution Approach 1:
The blade guard is designed as a movable component that can rotate between an outward position (when not in use) and an inward position (when needed for protection). This dynamic positioning allows the guard to be out of the way during cutting operations, maximizing blade access and cutting efficiency, while automatically moving inward when objects approach, thereby preventing user contact with the blades.
Solution Approach 2:
The blade guard acts as an intermediary barrier between the user and the blades. It is mounted on the chassis between the user's potential contact point and the rotating blades, physically blocking direct access while allowing the blades to remain positioned close to the lateral sides for optimal cutting performance.
2Object-affected harmful factors
If blade guard is positioned inward, then user safety is improved, but cutting swath width is reduced
Solution Approach 1:
The blade guard rotates inward only when necessary for protection, rather than remaining in a fixed inward position. This allows the cutting blades to maintain their optimal position close to the lateral sides for maximum swath width during normal operation, while the guard dynamically moves inward only when objects approach, thus preserving cutting efficiency while providing safety.
3Adaptability or versatility
If blade guard is made movable, then adaptability is improved, but device complexity increases
Solution Approach 1:
The blade guard is mounted on a rotation mechanism that allows it to move between outward and inward positions. This simple rotational degree of freedom provides the necessary adaptability to respond to approaching objects while keeping the overall mechanism relatively straightforward and manageable.
Solution Approach 2:
The blade guard is equipped with a bump sensor that automatically detects approaching objects and triggers the guard to rotate inward for protection. This self-service capability eliminates the need for complex manual control systems, using the sensor's detection to automatically activate the protective motion through the mounted rotation mechanism.
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 blade guards effectively prevent user contact with the blades during manual handling and enable the blades to be positioned closer to the lateral sides, enhancing cutting efficiency by allowing a wider cutting swath while maintaining safety.
Implementation Method 1
The extension springs, for example, mount the first blade guard to the first lateral side of the chassis such that the extension springs are twisted in a first direction when the first blade guard is rotated toward the one or more blades of the cutting assembly. The extension springs, for example, mount the first blade guard to the first lateral side of the chassis such that the extension springs are twisted in a second direction when the first blade guard is rotated away from the one or more blades of the cutting assembly. The extension springs, for example, mount the first blade guard to the first lateral side of the chassis such that the extension springs are bent when the first blade guard translates away from the lawn and recedes into the chassis.
Data Source
Figure 1
Figure 2A~2C
Figure 3A
AI summary
An autonomous robot lawnmower includes a chassis, a drive supporting the chassis above a lawn and configured to maneuver the robot lawnmower about the lawn, and a motorized lawn cutting assembly including one or more blades. The robot lawnmower further includes a first blade guard movably mounted to a first lateral side of the chassis and extending from the chassis toward the lawn, and a second blade guard movably mounted to a second lateral side of the chassis and extending from the chassis toward the lawn.