Cable-Driven Lopping Shear Mechanism for Reduced Complexity
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Solution Overview
Problem
Existing cutting tools for pruning, such as loppers, face manufacturing complexity, maintenance issues, tangling of rope systems, reliability concerns, and limited force increase due to complex pulley and eccentric wheel mechanisms.
Innovation Solution
A lopping shear design featuring a pruning head with a blade and counter-blade mechanism utilizing a lever principle, internal wheels with different diameters to enhance cutting force, and a telescopic rod system with guided grooves to simplify maintenance and reduce jamming risks, along with an electrical motor and pulley system for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a complex pulley and rope system is used to increase applied force, then the force multiplication is achieved, but the manufacturing complexity and maintenance difficulty increase
Solution Approach 1:
The patent replaces the complex mechanical pulley and rope system with a cable-driven mechanism that uses a drum and cable arrangement. This substitution simplifies the overall mechanical complexity while maintaining the force multiplication capability through the cable tensioning system and drum mechanism.
Solution Approach 2:
The patent changes the mechanical parameters by using a cable-driven system with a drum instead of multiple pulleys. This parameter change reduces the number of moving parts and simplifies the force transmission mechanism while achieving the same or better force multiplication effect.
2Length of moving object
If a telescopic system with multiple channels and coils is used, then the reach is extended, but the rope tangling and maintenance problems increase
Solution Approach 1:
The patent extracts the rope system from the complex multi-channel telescopic mechanism and implements a separate, simplified cable-driven telescopic system. This extraction eliminates the tangling issues associated with ropes running through multiple channels and coils, while maintaining the telescopic extension capability.
Solution Approach 2:
The patent segments the telescopic system into distinct sections with guiding grooves and supports that prevent cable tangling. Each section has dedicated guiding elements that ensure smooth cable movement during extension and retraction, eliminating the jamming problems of integrated multi-channel systems.
3Force
If a chain-driven mechanism is used, then the force transmission is effective, but the maintenance requirements and lubrication needs increase
Solution Approach 1:
The patent substitutes the chain-driven mechanism with a cable-driven system. This substitution eliminates the need for chain lubrication and reduces maintenance requirements, while the cable tensioning system maintains effective force transmission through the drum and cable arrangement.
4Force
If eccentric wheels and lever systems are used to increase force, then the force multiplication is achieved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent replaces the eccentric wheel and lever system with a cable-driven mechanism using a drum and cable arrangement. This substitution simplifies manufacturing by eliminating the need for precision eccentric wheel fabrication and complex lever linkages, while maintaining force multiplication through cable tensioning.
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 solution provides a reliable, easy-to-maintain lopping shear with increased cutting force, reduced operator fatigue, and improved safety by simplifying the mechanism and enhancing the force application efficiency.
Implementation Method 1
side extension of the orthogonal blade with respect to the cutting surface: said extension forms the arm of a lever suitable for increasing the retraction force exerted by the operator on the cutting point
Implementation Method 2
a return elastic means (18) for the return to the open position
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Lopping shear or lopper of the scissor type provided with a pruning head (29) comprising a blade (1) and a counter-blade (2) supported by a blade-support (3) placed on a support (8) of the pruning head (29), in which the pruning head is provided with a movement device (9, 12, 19) intended to control a reciprocal closing movement of blade and counter-blade from an open position to a closed position for cutting a piece placed in the opening formed by blade and counterblade, comprising an electrical driving system (13, 21, 27) with return means (10, 11) of a rope or belt (22).