Lopper With Adjustable Transmission Ratio For Branch Cutting
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Solution Overview
Problem
Existing loppers and pruning shears do not allow for a simple variation of the transmission ratio between the actuating means and the lopping assembly during the cutting process without interrupting the cutting movement or requiring changes at the lopping assembly itself.
Innovation Solution
The lopper design includes a latch connection between the actuating elements of the operating handle, allowing for a secondary transmission ratio to be engaged during the cutting process, enabling a change in the force exerted on the lopping assembly by moving the handle element further, thus adjusting the transmission ratio from 1:1 to 2:1 without interrupting the cutting motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed transmission ratio is used in the lopper, then the structure is simple and reliable, but the cutting force cannot be adapted to different branch thicknesses during the cutting process
Solution Approach 1:
The patent applies the dynamics principle by making the transmission ratio adjustable during operation. The actuating element can be moved along the pole to different positions, changing the transmission ratio dynamically based on the cutting requirements. This allows the lopper to adapt to different branch thicknesses without requiring complete disassembly or complex gear mechanisms, achieving versatility while maintaining relatively simple structure.
2Adaptability or versatility
If the transmission ratio is changed at the lopping assembly, then the adaptability to different cutting forces is improved, but the cutting movement must be interrupted and the lopper removed from the tree
Solution Approach 1:
The patent introduces an intermediary mechanism - the actuating element that can be independently positioned along the pole. This intermediary allows transmission ratio adjustment without affecting the lopping assembly directly. The user can adjust the actuating element position while the lopper remains engaged with the branch, eliminating the need to interrupt cutting or remove the tool from the workpiece.
3Length of moving object
If a telescopic pole is used to adapt to different heights, then the reachability is improved, but the structural complexity and stability may be reduced
Solution Approach 1:
The patent applies segmentation by dividing the pole into telescopic sections that can be extended or retracted to achieve different lengths. This segmented structure allows the pole to adapt to various heights while maintaining structural integrity through proper connection mechanisms between sections. The segmentation enables length adjustment without requiring a completely complex telescopic mechanism throughout the entire structure.
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 allows for efficient cutting of both thin and thicker branches without needing to remove the lopper from the tree, as the user can adjust the transmission ratio during use to manage varying cutting forces, ensuring consistent operation.
Implementation Method 1
resilient means
Implementation Method 2
pull cable drive having a first end attached to a crank lever connected to the movable knife
Implementation Method 3
block and tackle system
Data Source
AI summary
A lopper a lopping assembly mounted to an upper end of a pole, said lopping assembly includes a movable knife and a counter knife. The movable knife is connected via a first transmission and connection assembly to an operating assembly disposed at a lower end of the pole, which is configured to move the movable knife and/or the counter knife in a direction to one another. The operating assembly includes first and second actuating elements. The first actuating element is coupled to the first transmission and connection assembly and the second actuating element is coupled via a second transmission and connection assembly and releasable latching assembly to the first actuating element. Movement of the second actuating element away from the first actuation element causes, via the second transmission and connection assembly, a movement of the first actuating element in said first direction.