Garden Tool Selector Mechanism for Safe Handle Rotation

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Solution Overview

Problem

Existing gardening and land maintenance devices lack mechanisms to ensure safe operation by preventing accidental rotation of the cutting tool during handling, which can lead to unsafe conditions and reduced effectiveness of maintenance operations.

Innovation Solution

A device with a selector mechanism that allows or prohibits angular movement between the housing and handle, featuring a coupling element and control portion to limit movement of the drive control, ensuring safe operation by preventing accidental activation of the cutting tool during handle rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the handle is allowed to rotate freely relative to the housing to enable comfortable positioning, then the ease of operation is improved, but the safety deteriorates due to risk of accidental cutting tool activation during rotation

Engineering Contradiction:
Improveease of positioningVSAvoidsafety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a dynamic locking mechanism where the selector can be moved between locked and unlocked positions. When locked, the handle is fixed relative to the housing; when unlocked, the handle can rotate freely. This dynamic state change allows the system to switch between safety (locked during operation) and ease of positioning (unlocked during handling), resolving the contradiction between these two requirements.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the drive control is made movable to allow speed variation, then the ease of operation is improved, but the reliability deteriorates due to potential accidental activation

Engineering Contradiction:
Improveease of controlVSAvoidsafety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The selector acts as an intermediary mechanism between the user and the drive control. It mediates the state of the system by controlling whether the drive control can move. When the selector is in the locked position, it prevents the drive control from moving, thereby preventing accidental activation. When unlocked, the drive control can be moved for speed adjustment. This intermediary mechanism resolves the contradiction by controlling the conditions under which the drive control becomes movable.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4477059A1Device for maintenance of a land or garden
Publication Date: 2024.12.18 STIGA S P A IN BREVE ANCHE ST SPA
  • EP4477059A1 patent drawingFigure 1
  • EP4477059A1 patent drawingFigure 2
  • EP4477059A1 patent drawingFigure 3

AI summary

The present invention relates to a device for the maintenance of land or a garden, which comprises a housing (4) housing a motor (3) connected to a work tool (2) and a handle (5) connected to the housing and configured to allow a user to manoeuvre the device. The device further comprises a selector (6) carried by the handle (5) and configurable between a locked position in which it engages the housing to fix it angularly to the handle, and a released position in which it disengages the housing to allow an angular movement thereof relative to the handle. The selector (6), during the movement between the locked position and the released position and vice versa, is configured to limit the movement, relative to the motor, of a drive control (7) intended to control the operations of the motor itself.