Reversible Grass Cutting Head for Dual Rotation Brush Cutters

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing grass cutting heads require separate versions for brush cutters rotating clockwise and counter-clockwise due to asymmetrically shaped teeth and projections, limiting their versatility and increasing manufacturing and sales costs.

Innovation Solution

A grass cutting head design featuring a reversible element with two series of teeth that can be alternately positioned to allow rotation in one direction while preventing it in the opposite direction, enabling the head to be used on brush cutters with either rotation direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the teeth and projections are shaped with an inclined surface to allow manual rotation of the spool, then winding of the line is enabled, but angular locking between spool and housing is ensured only in one direction of rotation

Engineering Contradiction:

Improvemanual winding capabilityVSAvoidcompatibility with both rotation directions

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The housing is divided into a fixed portion and a reversible portion that can be rotated 180 degrees. The reversible portion contains the teeth that engage with projections on the spool. By segmenting the housing this way, the patent enables adaptation to different rotation directions while maintaining the winding function through the inclined surfaces on the teeth.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The reversible portion of the housing is made dynamically adjustable, allowing it to be rotated 180 degrees to change the orientation of the teeth. This dynamic reconfiguration enables the same head to work with brush cutters rotating in either clockwise or counter-clockwise direction, while the inclined surfaces on the teeth continuously provide the winding function regardless of rotation direction.

Inventive Principle:

Principle #15Dynamics

2Reliability

If separate head versions are produced for right and left rotation brush cutters, then proper functionality is ensured, but manufacturing complexity and inventory requirements increase

Engineering Contradiction:

Improvefunctional compatibilityVSAvoidnumber of head versions

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a universal head design where a single head version can function with both right-rotating and left-rotating brush cutters. The reversible portion with rotatable teeth configuration allows the same head to adapt to different rotation directions, eliminating the need for separate head versions and reducing manufacturing complexity while maintaining full functional compatibility.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If a single head design is used for both rotation directions, then manufacturing and inventory are simplified, but proper locking and winding function cannot be ensured for both directions

Engineering Contradiction:

Improvenumber of head versionsVSAvoidlocking function

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

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 design allows the head to be used on both clockwise and counter-clockwise rotating brush cutters, reducing manufacturing and sales complexities while ensuring proper functionality, thereby increasing market reach and user compatibility.

Implementation Method 1

an elastic member elastically stresses the spool with respect to the housing

Methodology Applied

Scientific EffectElastic stress: Elasticity

Implementation Method 2

a delivery of limited quantities of line towards the outside of the head thanks to the effect of the centrifugal force which acts on the members formed by the head during the rotation

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2273867B1A line-type grass cutting head which can be alternatively used on machines with left or right rotation

Publication Date: 2016.01.06 ARNETOLI MOTOR

Figure 1~2
Figure 3~4
Figure 5~6

AI summary

The head comprises a housing (3a, 3B) for a winding spool (7) for winding the cutting line (F), provided with projections (15, 19) cooperating with teeth (17, 21) integral with the housing. The teeth and the projections are arranged in such a way so as to allow a stepped rotation of the spool with respect to the housing, when said spool is translated alternatively in opposite directions parallel to the axis of the head. The head comprises a first series of teeth and a second series of teeth (21 A, 21 B) which can be used alternatively and which are suitable each to allow the rotation of the spool (7) in one direction and to prevent the rotation in the opposite direction with respect to the housing.