Power Lopper Attachment With Mid-Stroke Blade Return Mechanism

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Solution Overview

Problem

Existing electric loppers face issues with the upper cutter not returning to the open position promptly, especially when dealing with large items or before completing a cut, leading to inefficiencies and potential user inconvenience.

Innovation Solution

A lopper design incorporating a drive shaft, primary and secondary gears, a ratchet gear, engagement flags, and a dampened lag bolt mechanism that allows the cutting blade to automatically return to the open position upon trigger release, utilizing a mechanical system without reliance on electronics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the upper cutter is designed to fully close before returning to open position, then the cutting completeness is improved, but the operation flexibility deteriorates when dealing with large items

Engineering Contradiction:

Improvecutting completenessVSAvoidoperation flexibility

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent implements a dynamic return mechanism where the upper cutter can return to the open position at any point during the cutting stroke, not just after completing the cut. The trigger mechanism allows the user to interrupt the cutting cycle and return the blade to the open position mid-stroke, providing operational flexibility while maintaining cutting completeness when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The trigger mechanism provides real-time feedback to the user about the cutting blade's position and status. When the trigger is released, the system automatically detects and executes the return to open position, allowing the user to control the cutting process dynamically based on the size of the material being cut.

Inventive Principle:

Principle #23Feedback

2Productivity

If the upper cutter returns to open position automatically, then the productivity is improved, but the mechanism complexity increases

Engineering Contradiction:

Improvecutting efficiencyVSAvoidmechanism complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The upper cutter is designed to return to the open position automatically through a self-service mechanism driven by the trigger release action. The mechanical system uses the existing drive shaft and gear components to power the return motion, eliminating the need for separate electronic motors or complex control systems while maintaining high productivity.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces electronic control systems with a purely mechanical return mechanism. The drive shaft, primary gear, and secondary gear work together to provide the mechanical force needed for the upper cutter to return to the open position, simplifying the overall system while maintaining automated operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If a simple trigger mechanism is used, then the ease of operation is improved, but the reliability of automatic return deteriorates

Engineering Contradiction:

Improvetrigger operation simplicityVSAvoidautomatic return reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The trigger mechanism is designed to engage the upper cutter in a preliminary action before the actual cutting stroke begins. When the trigger is pulled, it immediately initiates the closing motion of the upper cutter, and when released, it automatically initiates the return to open position, ensuring reliable operation throughout the entire cutting cycle.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The trigger mechanism acts as an intermediary between the user's input and the upper cutter's motion. It translates the simple pull and release action into controlled mechanical motion through the drive shaft and gear system, ensuring that the automatic return function is reliably activated without requiring complex user input.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Ensures reliable and robust operation with the cutting blade returning to the open position automatically, enhancing user convenience and efficiency by allowing one cut per trigger pull.

Implementation Method 1

a dampened lag bolt slidably received within the lag groove to move relative to the secondary gear between a permissive position permitting the engagement flag to the unengaged position and a restrictive position holding the engagement flag in the engaged position

Methodology Applied

Scientific EffectDamping: Damping

Data Source

PatentUS20260053098A1Power lopper attachment

Publication Date: 2026.02.26 TECHTRONIC CORDLESS GP

AI summary

A lopper or lopper head attachment includes a primary gear, an engagement flag, and a dampened lag bolt. The primary gear may be in mechanical communication with a drive shaft. The secondary gear may be enmeshed with the primary gear, the secondary gear defining a lag groove. The engagement flag may be rotatably mounted to the secondary gear to move between an unengaged position and an engaged position. The dampened lag bolt may be received within the lag groove to move relative to the secondary gear between a permissive position permitting the engagement flag to the unengaged position and a restrictive position holding the engagement flag in the engaged position.