Hedge Trimmer Tapping Body Waved Edge Dirt Prevention

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Solution Overview

Problem

Existing hedge trimmer heads with 'tap and go' mechanisms suffer from dirt penetration into the casing due to vacuum effects during rotation, leading to mechanical obstruction and reduced functionality.

Innovation Solution

A tapping body with a projecting edge having a waved or stepped profile is integrated into the design, which surrounds the side portion concentrically and protrudes radially, effectively preventing dirt entry by increasing pressure and reducing aerodynamic noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a slot is maintained between the edge of the lower opening and the outer surface of the tapping body to ensure clearance, then the tapping body can move freely to enable the 'tap and go' mechanism, but dirt enters the casing through the slot during rotation causing mechanical obstruction

Engineering Contradiction:
Improvetapping body movementVSAvoiddirt penetration
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A flexible seal element is introduced between the tapping body and the casing to close the slot during rotation. The seal element can deform to accommodate the tapping body's movement while maintaining contact to prevent dirt ingress, thus resolving the contradiction between free movement and dirt protection.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The seal element acts as an intermediary between the tapping body and the external environment. It mediates by allowing the tapping body to move freely while simultaneously blocking the slot to prevent dirt from entering the casing during rotation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the tapping body is pressed against the ground to release the anchoring device, then the reel can rotate to unwind the cutting wire, but strong vacuum is produced during head rotation that attracts dirt into the casing

Engineering Contradiction:
Improvereel rotationVSAvoiddirt attraction
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The flexible seal element closes the slot between the tapping body and casing during rotation, preventing the vacuum effect from attracting dirt into the casing while still allowing the reel to rotate freely for wire unwinding.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The seal element converts the harmful vacuum effect into a beneficial sealed environment. By sealing the slot, the vacuum is contained and can no longer attract external dirt, while the internal mechanism continues to function normally.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Object-affected harmful factors

If a seal is added to prevent dirt from entering the casing, then dirt penetration is blocked, but the mechanism complexity increases

Engineering Contradiction:
Improvedirt preventionVSAvoidsealing mechanism
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

A simple flexible seal element is used instead of complex sealing mechanisms. The seal's flexibility allows it to accommodate the tapping body's movement while maintaining a closed slot, providing effective dirt prevention with minimal added complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The flexible seal element is self-adjusting and requires no additional actuation or control mechanisms. It automatically maintains contact to seal the slot while accommodating the tapping body's movement, thus preventing dirt ingress without increasing operational complexity.

Inventive Principle:
Principle #25Self-service

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 prevents dirt from entering the casing, maintaining the functionality of the 'tap and go' mechanism while reducing noise and aerodynamic effects, thus ensuring continuous operation without mechanical obstruction.

Implementation Method 1

effectively preventing dirt entry by increasing pressure

Methodology Applied
Scientific EffectPressure increase: Pressure Increase

Implementation Method 2

During rotation of the head occurring relative to said slot, a strong vacuum is produced which attracts dirt inside the casing

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP3011821B1A tapping body for a head for an edge trimmer and a head for an edge trimmer
Publication Date: 2020.01.22 TECOMEC
  • EP3011821B1 patent drawingFigure 1~1a
  • EP3011821B1 patent drawingFigure 2~2a
  • EP3011821B1 patent drawingFigure 3~3a

AI summary

A tapping body for a head for hedge trimmer comprising a lower portion (2), destined to be tapped or pressed onto the ground, and a side portion (3) which is so structured as to be arranged through a lower opening (11) of a casing (10) of the head; a projecting edge (4), which protrudes externally to the side portion (3) and is provided with a lower waved profile (41).