Auto-Retracting Utility Knife Blade Mechanism
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Solution Overview
Problem
Existing utility knives pose a risk of injury due to exposed blades and are not versatile enough to cut various materials of different thicknesses and shapes, such as corrugated board, as they require multiple specialized knives and can damage products during cutting.
Innovation Solution
A knife with an auto-retracting cutting blade mechanism, featuring a handle with a blade shuttle and transmission system that automatically retracts the blade into a safe position after disengagement from a workpiece, allowing for adjustable blade extension and reduced user effort, while minimizing exposure and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the blade is exposed for cutting operation, then cutting capability is improved, but user safety deteriorates due to risk of injury
Solution Approach 1:
The blade is automatically retracted to a concealed position upon disengagement from the workpiece through a spring-loaded mechanism. This preliminary action of retraction occurs automatically after cutting, eliminating the need for manual blade retraction and ensuring the blade is concealed during non-operational periods to prevent user injury while maintaining exposure during cutting operations.
2Manufacturing precision
If the blade extension is fixed for specific material, then cutting precision for that material is improved, but adaptability to different materials deteriorates
Solution Approach 1:
The blade extension distance is made adjustable through a mechanism that allows the blade to be positioned at multiple extension distances from the aperture. Users can select different blade extension distances based on the specific material and thickness requirements, enabling the same knife to adapt to various materials including single wall, twin wall, and triple wall corrugated board while maintaining optimal cutting precision for each material type.
3Ease of operation
If the blade extends deeper for thick materials, then cutting capability for thick materials is improved, but product damage risk deteriorates
Solution Approach 1:
The adjustable blade extension mechanism allows users to precisely control the blade extension distance to match the specific thickness of the material being cut. For thick materials like triple wall corrugated board, the blade can be extended further to ensure complete penetration, while for thinner materials, the extension is reduced to prevent over-penetration and product damage, thus adapting the cutting depth to each specific application.
4Device complexity
If manual blade retraction is required, then device complexity is reduced, but user safety and convenience deteriorate
Solution Approach 1:
The spring-loaded automatic retraction mechanism performs the blade retraction function automatically upon disengagement from the workpiece. The spring force engages to pull the blade back to the concealed position without requiring any manual intervention from the user. This self-service retraction system enhances user safety by ensuring the blade is always concealed during non-operational periods, eliminating the risk of injury from forgotten blade retraction while adding minimal complexity to the overall device.
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 auto-retracting mechanism enhances safety by preventing blade exposure, allows for multiple depths of cut, reduces user effort, and extends blade life by minimizing friction, ensuring cleaner cuts and reducing the risk of injury and product damage.
Implementation Method 1
The first spring may be coupled to the trigger and may be adapted to direct the lever to engage the blade shuttle in the first extended position and the second extended position and rotate the lever to disengage the lever and the blade shuttle in the cutting position
Implementation Method 2
The second spring may be coupled to the handle and the blade shuttle and may be adapted to automatically retract the blade shuttle from the cutting position to the rest position
Implementation Method 3
The third spring may be adapted to act between the handle and the trigger and cooperate with the first and second springs to maintain a substantially constant force magnitude required to actuate the trigger and maintain the trigger in the actuated position
Data Source
AI summary
A knife includes a handle enclosing one or more of a blade, a blade shuttle, a transmission, and a trigger, where the handle includes a blade aperture. The blade shuttle is longitudinally moveable relative to the handle from a rest position to a first extended position and the blade shuttle is moveable longitudinally from the first extended position to a cutting position when the blade is engaged in a workpiece. The blade shuttle is automatically retracted from the cutting position to the rest position when the blade is disengaged from the workpiece. The blade is detachably secured within the blade shuttle and protrudes a first distance through the blade aperture at the first extended position. The blade is extended from the first distance a substantially fixed length when engaged in the workpiece. The blade is adapted to automatically retract within the handle when disengaged from the workpiece.