Adjustable Pivot Cutting Tool Resolving Force Speed Trade-off
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Solution Overview
Problem
Conventional cutting tools with a single pivot point struggle to switch between greater cutting force and speed while maintaining symmetric handle movement, affecting efficiency when cutting thick or thin branches.
Innovation Solution
A cutting tool with three pivot points and a fourth adjustable pivot point allows users to change the lever length by switching the fourth pivot point closer to the handles for faster speed or farther for greater force, maintaining symmetric handle movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the pivot point is located farther from the handles, then greater cutting force is achieved, but cutting speed decreases
Solution Approach 1:
The invention makes the pivot point location dynamic rather than fixed. The handle assembly can pivot relative to the blade assembly at different positions along the blade, allowing the user to adjust the pivot point location based on whether cutting force or speed is the priority for the current task.
Solution Approach 2:
The invention changes the geometric parameter of the pivot point location. By providing multiple possible pivot locations along the blade and allowing selection among them, the system can optimize the lever arm length to change between force and speed characteristics.
2Speed
If the pivot point is located closer to the handles, then faster cutting speed is achieved, but cutting force decreases
Solution Approach 1:
The invention makes the pivot point location dynamic rather than fixed. The handle assembly can pivot relative to the blade assembly at different positions along the blade, allowing the user to adjust the pivot point location based on whether cutting force or speed is the priority for the current task.
Solution Approach 2:
The invention changes the geometric parameter of the pivot point location. By providing multiple possible pivot locations along the blade and allowing selection among them, the system can optimize the lever arm length to change between force and speed characteristics.
3Speed
If gears are used to increase turning speed, then speed advantage is obtained, but symmetric handle movement is lost
Solution Approach 1:
The invention removes the gear mechanism entirely from the system. Instead of using gears to modify speed, it uses a purely geometric solution with multiple pivot points that naturally provides speed variation through lever arm length changes while preserving symmetric handle movement.
Solution Approach 2:
The invention changes the geometric parameter of the pivot point location to achieve speed variation. By moving the pivot point closer to or farther from the handles, the system obtains speed advantage or force advantage respectively, without introducing asymmetric mechanical elements like gears.
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
Enables efficient cutting of both thick and thin branches with symmetric arm motion, reducing user fatigue and improving targeting accuracy by adjusting the lever length dynamically.
Implementation Method 1
The cutting tool is based on the idea of comprising three pivot points and a fourth changeable pivot point... The user can switch the fourth pivot point further from the handles when cutting thick branches for greater cutting force and closer to the handles when cutting thin branches for faster speed
Data Source
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AI summary
A cutting tool, comprising a first blade (5) having a cutting edge, a second blade (6) having a cutting edge, and pivotally connected to the first blade at a first pivot point (7). A first handle (1) is pivotally connected to the first blade (5) at a second pivot point (8), a second handle (2) is pivotally connected to the second blade (6) at a third pivot point (9), the first handle (1) is pivotally connected to the second handle (2) at an adjustable fourth pivot point (11), and the cutting tool further comprises a switch arrangement (10) comprising a switch (12) allowing a user to change location of the fourth pivot point (11) from a proximal pivot point (11a) to a distal pivot point (11b).