Grass Shears Handle Device Ergonomic Pivot Lever

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Solution Overview

Problem

Existing grass shears lack ergonomic design, leading to inefficient handling and precise edge cutting due to an unfavorable center of gravity and pivot lever arrangement.

Innovation Solution

The grass shears feature a handle device with a handle part extending from the rear end, positioned above the cutting plane, and a pivoted lever connected to the handle body, allowing for ergonomic grip and force application, with a force transmission element like a traction cable and deflection means to facilitate cutting of grass and small branches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the handle part is positioned close to the cutting plane for compact design, then the device complexity is reduced, but the center of gravity becomes unfavorable leading to poor ergonomics

Engineering Contradiction:

Improveergonomic gripVSAvoidhandle device structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The handle part is extended in the longitudinal direction away from the cutting plane, utilizing the longitudinal dimension to reposition the center of gravity. This dimensional extension allows the handle to be positioned optimally for ergonomic gripping while maintaining a relatively simple structural implementation through the base part connection.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Force

If the pivoting lever is positioned far from the pivot axis to increase actuating force, then the force application is improved, but the fingers are spaced further from the pivot axis reducing control precision

Engineering Contradiction:

Improveactuating forceVSAvoidcutting precision

Core Design Contradiction:

ForceVSMeasurement precision

Solution Approach 1:

The pivoting lever is designed to be movable relative to the handle part, allowing dynamic adjustment of its position. This enables the lever to be positioned optimally for each cutting operation, balancing force application and precision control as needed, rather than being fixed in a suboptimal position.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The actuation mechanism is divided into separate components: the pivoting lever for force application and the shearing blade for cutting. This segmentation allows independent optimization of each component's position and function, enabling the lever to be positioned for maximum force while the blade maintains precise cutting alignment.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If the handle part extends parallel to the cutting plane for ergonomic grip, then the center of gravity is optimized, but the angle with the cutting plane becomes unfavorable for certain cutting angles

Engineering Contradiction:

Improvehandle grip comfortVSAvoidcutting angle adaptability

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The handle device allows the handle part to be positioned at an optimized angle relative to the cutting plane, and the pivoting lever can be dynamically adjusted during operation. This dynamic capability enables adaptation to different cutting angles and user preferences while maintaining the ergonomically optimized handle position.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP2425706B1Grass shears with a handle device

Publication Date: 2016.09.21 HUSQVARNA AB

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AI summary

The blade drive (2) has a blade set (3) including a fixed blade (31) and a mobile blade (33), and a bearing device. The blade set is mounted by the bearing device in such a manner that it pivots about a rotational axis (D) oriented in a cutting direction parallel to a cutting plane (S). The rotational axis lies approximately in the cutting plane.