Convertible Hand Tool Shear Assembly for Force-Speed Tradeoffs
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Solution Overview
Problem
Existing hand tools, such as outdoor shears and loppers, are limited in their ability to apply varying amounts of force and require repeated motions for cutting members of different thicknesses and densities, often necessitating separate tools for compound and single action applications.
Innovation Solution
A hand tool design that allows for a shear assembly to selectively articulate between compound and single action movements, enabling a user to switch between operating modes without disassembly, using a fastener system that pivots and locks the handles and cutting blade for different cutting actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hand tools are designed for compound action to apply greater force, then force application capability is improved, but cutting speed and efficiency for lighter members deteriorates
Solution Approach 1:
The hand tool incorporates a convertible linkage system that dynamically changes its mechanical configuration. The linkage can be repositioned between a compound action configuration (providing greater mechanical advantage for force-intensive cutting) and a single action configuration (providing faster cutting motion). This dynamic reconfigurability allows the tool to adapt its kinematic characteristics based on the specific cutting task, resolving the contradiction between force application capability and cutting speed.
2Productivity
If hand tools are designed for single action to enable quicker cutting, then cutting speed is improved, but force application capability for thicker members deteriorates
Solution Approach 1:
The convertible linkage system allows the user to reposition the linkage to switch between single action and compound action modes. In single action mode, the linkage configuration optimizes for speed and efficiency when cutting lighter members. When greater force is needed for thicker members, the linkage can be repositioned to engage compound action, providing the necessary mechanical advantage. This dynamic adaptability resolves the contradiction between cutting speed and force application capability.
3Adaptability or versatility
If separate hand tools are used for compound and single action applications, then versatility across different cutting scenarios is improved, but device complexity and number of tools required worsens
Solution Approach 1:
The hand tool is designed with a convertible linkage system that enables a single tool to perform both compound action and single action cutting operations. By incorporating repositionable linkages and adjustable connection points, the tool can be configured for different cutting scenarios, eliminating the need for users to maintain separate tools for different applications. This multi-functionality resolves the contradiction between versatility and device complexity by consolidating multiple functions into one tool.
Data Source
AI summary
A hand tool including a shear assembly is provided, including a first handle, a second handle including a cutting member, and a cutting blade. The cutting blade forms a first opening and a second opening. The first handle is attachable in a first operating mode to the cutting blade at the first opening via a first fastener. The first handle is attachable in a second operating mode to the cutting blade at the second opening via the first fastener. The cutting blade is attached in pivotal arrangement to the second handle via a second fastener.