Pulling Member Offset Angle for Pruning Tool Cable

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Solution Overview

Problem

Existing pruning tools with drive cable arrangements often suffer from cluttered cable configurations and complex kinematics, leading to inefficient pruning operations and potential obstructions during use.

Innovation Solution

A pruning tool with a drive cable arrangement where the pulling member has a gripping portion offset from the pole's longitudinal axis, forming an angle with the drive cable to prevent tilting and obstruction, and includes a coiling and uncoiling mechanism for ergonomic handling and storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the drive cable is routed close to the pole with a spooling arrangement, then the cable configuration becomes compact, but the cable may lie on the carrier causing clutter and obstruction during pruning operations

Engineering Contradiction:
Improvecable configuration compactnessVSAvoidcable obstruction and clutter
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the drive cable from the traditional spooling arrangement on the carrier and relocates it to a dedicated pulling member mounted on the pole. This separation removes the cable path from the carrier area, eliminating the clutter and obstruction problem while maintaining cable routing efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a pulling member as an intermediary component between the pole and the drive cable. This mediator provides a dedicated mounting structure for the cable, allowing it to be routed away from the carrier and preventing interference with pruning operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If a complex lever arrangement with multiple interdependent levers is used, then force multiplication is achieved, but the pruning kinematics becomes complex and difficult to operate

Engineering Contradiction:
Improveforce multiplicationVSAvoidpruning kinematics complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent replaces the complex mechanical lever arrangement with a cable-driven pulling mechanism. The drive cable transmits force directly from the pulling member to the cutting implement, eliminating the need for multiple interdependent levers while maintaining force multiplication through the cable tension system.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses a flexible drive cable instead of rigid lever connections. This flexible cable allows for simpler kinematics while transmitting the necessary forces, reducing the complexity of the mechanical system compared to rigid lever arrangements.

Inventive Principle:
Principle #30Flexible shells and thin films

3Volume of moving object

If the pulling member is mounted close to the pole surface, then the structure becomes compact, but the drive cable may be obstructed by the pole during actuation

Engineering Contradiction:
Improvepulling member compactnessVSAvoiddrive cable obstruction by pole
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent positions the pulling member and drive cable in a different spatial dimension relative to the pole, mounting the pulling member on the pole surface but routing the cable to clear the pole's longitudinal path. This dimensional arrangement prevents obstruction while maintaining structural compactness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Force

If the drive cable forms a large angle with the pole axis, then actuation force is improved, but the cable may tilt and cause obstruction or difficult actuation

Engineering Contradiction:
Improveactuation forceVSAvoidactuation smoothness
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent optimizes the angle parameter between the drive cable and pole axis, maintaining it at less than 20 degrees. This parameter optimization balances the actuation force requirements with smooth operation, preventing cable tilting and obstruction while ensuring sufficient cutting force is transmitted.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3065533B1Pulling member for pruning tool
Publication Date: 2018.04.18 HUSQVARNA AB
  • EP3065533B1 patent drawingFigure 1A
  • EP3065533B1 patent drawingFigure 1B
  • EP3065533B1 patent drawingFigure 2

AI summary

A tool (100) includes an implement (102) having at least one movable component (104) and a drive cable (126) attached to the at least one movable component at a first end (128) of the drive cable. Further, a pole (140) is coupled with the implement and a pulling member (142) is slidably mounted on the pole, wherein a second end (130) of the drive cable is coupled to the pulling member and a sliding movement of the pulling member is configured to actuate the at least one movable component of the implement through the drive cable. Further, the pulling member includes a gripping portion (143) having a gripping axis (GG') wherein the gripping axis is relatively offset to an outer surface (150) of the pole by a distance (O) and also, a first point of contact (148) of the drive cable with the pulling member from a direction of the implement is offset from the outer surface of the pole at a distance (O') close to the offset of the gripping axis. The drive cable extends along a line starting from the first point of contact towards the implement such that the drive cable forms an angle (α) equal to or less than 20 degrees at a second point of contact (135,135') relative to the longitudinal axis of the pole.