Handle Operating Lever Geometry for Ergonomic Finger Actuation
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Solution Overview
Problem
Existing hand-guided motorized working apparatuses, such as gardening and forestry tools, face challenges in providing comfortable and ergonomic actuation of operating elements, often requiring axial displacement or pivoting about a pivot axis parallel to the handle shank, which can lead to reduced user comfort and efficiency.
Innovation Solution
The operating device features a pivot operating lever actuated by a finger, with a finger rest region that extends along the outer side of the operating element receiving region, having a bent and/or angled course with both circumferential and axial direction components, allowing for comfortable and variable actuation by pivoting about a pivot axis perpendicular or oblique to the handle shank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the operating element is actuated by axial displacement or pivoting about a pivot axis parallel to the handle shank, then the operating mechanism is simple, but the user comfort and ease of operation deteriorates
Solution Approach 1:
The patent introduces a new dimension to the operating mechanism by allowing the operating element to pivot about a pivot axis that is oblique or perpendicular to the handle shank axis, rather than being constrained to axial displacement or pivoting about an axis parallel to the handle shank. This dimensional change in the pivot axis orientation enables more natural finger movement and improved ergonomics while maintaining mechanical simplicity through the single-pivot design
2Ease of operation
If the finger rest region has a straight course, then the manufacturing is simple, but the ease of operation deteriorates due to reduced actuation flexibility
Solution Approach 1:
The patent applies curvature to the finger rest region by designing it with a bent or angled course instead of a straight configuration. This curved geometry follows the natural arc of finger movement during actuation, providing multiple contact points and improved ergonomics. The curvature is implemented through standard bending or angling of the finger rest region, which remains manufacturable using conventional processes while significantly enhancing operational flexibility
3Productivity
If the pivot axis is parallel to the handle shank axis, then the mechanical structure is simple, but the actuation force required increases reducing efficiency
Solution Approach 1:
The patent changes the orientation parameter of the pivot axis from being parallel to the handle shank axis to being oblique or perpendicular to it. This parameter change in the pivot axis angle optimizes the mechanical advantage during actuation, allowing the user's finger to apply force more effectively. The oblique or perpendicular orientation creates a more favorable moment arm geometry, reducing the actuation force required while maintaining structural simplicity
Data Source
AI summary
A hand-guided motorized working apparatus and an operating device for the apparatus are provided. The operating device has a handle shank configured to be hand-gripped, an operating element receiving region adjoining the handle shank, and an operating unit which acts on the apparatus operation and includes an operating element which is held movably on the operating element receiving region for actuation by a finger of a hand gripping the handle shank, and has a finger rest region extending along an outer side of the operating element receiving region. In the operating device, the operating element is a pivot operating lever which is held on the operating element receiving region so as to be pivotable about a pivot axis, wherein the pivot axis extends with a main direction component perpendicular to a shank longitudinal axis of the handle shank, and wherein the finger rest region, in a longitudinal extension along the outer side of the operating element receiving region, has a bent and/or angled course with a circumferential direction component and an axial direction component.