Handheld Tool Housing Lever Pivot Axis Orientation

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Solution Overview

Problem

Existing hand-held tools face challenges in ergonomically arranging multiple operating elements due to the limitations of pivot axes aligned with the demolding direction of plastic housings, making it difficult to achieve an ergonomic layout and complicating assembly.

Innovation Solution

A housing part assembly that allows pivot axes of operating levers to be oriented differently from the demolding direction, using a holding device with a return spring and a shaft, enabling preassembly and easy attachment to the housing, thereby facilitating ergonomic arrangement and simplifying assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If pivot axes of operating levers are aligned with the demolding direction of the housing, then the housing production cost is reduced and assembly is simplified, but the ergonomic arrangement of multiple operating elements becomes difficult

Engineering Contradiction:
Improvehousing production costVSAvoidergonomic arrangement of operating elements
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The housing is divided into a first housing element and a second housing element that can be separated. The second housing element is removable from the first housing element, allowing the pivot axes of operating levers to be oriented in directions different from the demolding direction. This segmentation enables ergonomic arrangement of multiple operating elements while maintaining simple housing production through injection molding of individual elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A holding device is introduced as an intermediary component between the housing and the operating levers. The holding device includes a shaft that can be oriented at different angles relative to the demolding direction, allowing operating levers to be mounted with pivot axes in ergonomically optimal directions while the housing itself maintains its simple molded structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If multiple operating elements are arranged ergonomically with different pivot axis directions, then user interaction is improved, but the assembly complexity increases

Engineering Contradiction:
Improveergonomic arrangement of operating elementsVSAvoidassembly complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The holding device is designed to combine multiple operating elements with different pivot axis orientations into a single integrated assembly. This holding device can be pre-assembled with multiple levers and then attached as one unit to the housing, reducing the overall assembly complexity compared to mounting each lever separately with custom orientations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The holding device allows for preliminary assembly of operating elements before attachment to the housing. The shaft and operating levers can be pre-positioned and secured in the holding device with the correct ergonomic orientations, and then this pre-assembled unit is attached to the housing in a single operation, simplifying the overall assembly process.

Inventive Principle:
Principle #10Preliminary action

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

Enables an ergonomic arrangement of operating elements, improving user interaction, particularly with the thumb, and simplifies the assembly process by allowing preassembly of components, reducing assembly time and complexity.

Implementation Method 1

The assembly (8) comprises a return spring (13), the return spring (13) being arranged on the holding device (9) and being operatively connected to the lever (11)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4219083A1Housing part for a handheld tool and assembly for a housing part of a handheld tool
Publication Date: 2023.08.02 ANDREAS STIHL AG & CO KG
  • EP4219083A1 patent drawingFigure 1
  • EP4219083A1 patent drawingFigure 2
  • EP4219083A1 patent drawingFigure 3~4

AI summary

The invention relates to a housing part for a hand-held power tool with a base housing. The base housing comprises at least one first housing element with a demolding direction (6). Furthermore, the housing part comprises an assembly including a holding device (9) attached to the base housing (3), a lever (11) pivotably arranged on the holding device (9) about a pivot axis (12), and a switch (15) arranged on the holding device (9), wherein the lever (11) is operatively connected to the switch (15). The direction of the pivot axis (12) of the lever (11) and the demolding direction (6) of the first housing element (4) are different.