Dual Mode Ratchet Pruner with Cam-Actuated Pawl

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Solution Overview

Problem

Ratchet pruners are inefficient for cutting thick or dried stalks, requiring multiple strokes and slowing down the pruning process, and gardeners often need to carry both regular and ratchet pruners to determine the appropriate tool based on resistance, which does not enhance work efficiency.

Innovation Solution

A dual mode cutting tool with a mode selection control mechanism that engages or disengages the ratchet mechanism via a cam-actuated pawl, allowing the pruner to operate in either multi-stage or single-stage cutting modes, depending on user preference, by rotating a lever to switch between modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a ratchet mechanism is used for cutting thick or dried stalks, then the cutting capability is improved, but the time required for pruning increases significantly

Engineering Contradiction:
Improvecutting capabilityVSAvoidpruning time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The pruner incorporates a mode selection mechanism that dynamically switches between ratchet mode (for thick/dried stalks requiring multiple strokes) and direct cutting mode (for green/soft stalks). The operator can adapt the cutting mechanism in real-time based on the resistance encountered, optimizing both cutting capability and time efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameter of the cutting mechanism from fixed (either ratchet or direct) to variable (switchable between modes). By altering the engagement state of the ratchet mechanism through mode selection, the system adapts its cutting characteristics to match the workpiece properties, resolving the time-loss issue while preserving cutting capability when needed.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If an operator carries both ordinary and ratchet pruners to handle different cutting conditions, then the adaptability is improved, but the device complexity and portability are worsened

Engineering Contradiction:
Improveadaptability to different cutting conditionsVSAvoidnumber of tools required
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pruner is designed with dual functionality, integrating both ratchet mechanism and direct cutting capability within a single tool. The mode selection control allows the same device to perform multiple cutting functions, eliminating the need to carry separate pruners for different cutting conditions while maintaining full adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges two previously separate tools (ordinary pruner and ratchet pruner) into a single unified device. By combining the cutting mechanisms and providing mode selection, the patent reduces the number of tools the operator must carry and manage, simplifying the system while preserving versatility.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If a ratchet mechanism is used for precise multi-stage cutting, then the control precision is improved, but the productivity decreases

Engineering Contradiction:
Improvecutting control precisionVSAvoidpruning speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system dynamically adjusts the cutting control mechanism based on operational needs. When high precision is required (multi-stage cutting of thick stalks), the ratchet mechanism provides controlled incremental movement. When speed is prioritized (cutting of soft stalks), the direct cutting mode eliminates ratchet constraints, allowing rapid single-stage cutting.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the control parameter from fixed precision (ratchet-only) to variable precision (switchable between precise multi-stage and rapid single-stage cutting). This allows the operator to optimize the balance between cutting control precision and productivity based on the specific pruning task at hand.

Inventive Principle:
Principle #35Parameter changes

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 faster and more efficient pruning by allowing the user to choose between multi-stage and single-stage cutting modes, reducing the time required to cut thick or dried stalks and improving overall pruning speed and efficiency.

Implementation Method 1

A dual mode cutting tool with a mode selection control mechanism that engages or disengages the ratchet mechanism via a cam-actuated pawl

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP2637493B1Dual mode ratchet pruners
Publication Date: 2016.03.30 WP INT PTY LTD
  • EP2637493B1 patent drawingFigure 1~2
  • EP2637493B1 patent drawingFigure 3
  • EP2637493B1 patent drawingFigure 4~5

AI summary

Pruners and loppers have dual mode operation in that the blade is closed with a single squeeze or with multiple squeezes and a rotatable selector selects the desired mode. The blade has a rocker arm with ratchet teeth formed in a window in the arm. The scissor handle has a radius arm which ends in a pawl which can engage the ratchet nearer the pivot axis of the blade or further from it.