Pivotable Hedge Trimmer Handles and Mechanical Blade Stop

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Solution Overview

Problem

Conventional hedge trimmers have fixed cutting planes and handles, limiting ergonomic adjustments for different cutting situations, particularly when transitioning between horizontal and vertical cuts, and lack efficient mechanical shift actuation for power distribution and safety.

Innovation Solution

The hedge trimmer design features pivotable front and rear handles connected to the handle housing, allowing optimal adjustment between cutting positions, and a mechanical shift actuation transmission system using a rotary axis with a locking pin for instantaneous blade stoppage upon handle release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the motor unit is permanently installed in the handle housing with fixed cutting plane, then the structure is simple and stable, but the adaptability to different cutting situations is limited

Engineering Contradiction:
Improveadaptability to different cutting situationsVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The motor unit is made pivotable relative to the handle housing about a lateral axis, allowing the cutting plane to be dynamically adjusted between horizontal and vertical positions. This dynamic arrangement enables the same device to adapt to different cutting situations without requiring multiple separate devices or complex reconfiguration mechanisms.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the handles are fixed relative to the motor unit, then the structural stability is high, but the ergonomic handling for different cutting situations is limited

Engineering Contradiction:
Improveergonomic handlingVSAvoidhandle arrangement complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The front and rear handles are made pivotable relative to the handle housing, allowing them to be dynamically adjusted to optimal positions for different cutting situations. The pivotable rear handle can be positioned for horizontal or vertical cutting, while the front handle can be adjusted for ergonomic support during various operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The handle system is segmented into independently pivotable front and rear handles, each capable of adjustment relative to the housing. This segmentation allows each handle to be optimized for specific ergonomic requirements during different cutting operations.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If the motor unit is positioned to enable horizontal cutting, then horizontal cut capability is improved, but vertical cut capability is compromised

Engineering Contradiction:
Improvecutting direction versatilityVSAvoidmotor unit positioning complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The motor unit is mounted on a pivotable carrier that can be rotated about a lateral axis, allowing the cutting plane to be dynamically oriented for either horizontal or vertical cutting. This single dynamic positioning mechanism replaces the need for multiple fixed motor units or complex reconfiguration systems.

Inventive Principle:
Principle #15Dynamics

4Reliability

If mechanical shift actuation transmission is implemented, then the reliability of instantaneous stoppage is improved, but the device complexity increases

Engineering Contradiction:
Improveinstantaneous stoppage reliabilityVSAvoidactuation transmission complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A mechanical linkage with a locking pin serves as an intermediary mechanism between the handle actuation and the motor switch. When the handle is released, the spring-driven locking pin engages with the transmission gear to mechanically ensure instantaneous stoppage of the blades, providing reliable feedback control.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses the handle's own movement (or lack thereof) to automatically trigger the stoppage mechanism through the mechanical linkage and spring-driven locking pin, eliminating the need for separate electronic sensors or complex control systems.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP1733612B1Hedge trimmer
Publication Date: 2008.04.09 WOLF GERATE GMBH
  • EP1733612B1 patent drawingFigure 1
  • EP1733612B1 patent drawingFigure 2
  • EP1733612B1 patent drawingFigure 3

AI summary

The hedge trimmer has a front grasp (12) and a back grasp (14) having grasp housings (10). Between the grasps, blades (26) are provided and connected to a transmission (24) propelled by an electric motor (22). The grasp housing is provided as bridge and carries between its bridge arms (18, 20) a crankshaft housing with the blades supported and adjusted over joints (19, 20) with their axis X-X aligning with one another.