Guide Tube Handle Locking Layout for Ergonomic Motor Control

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Solution Overview

Problem

Existing hand-held work devices lack an ergonomic and compact design for their control elements, leading to inefficient force transmission and potential unintentional activation.

Innovation Solution

The second control element is pivotably mounted about a second pivot axis that lies in a plane perpendicular to the fourth pivot axis, allowing for ergonomic operation and effective force transmission, while the third control element acts on a holding element to maintain the second control element's actuated position, decoupling their movements for ergonomic and simple operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple control elements are provided for different functions, then the device functionality is improved, but the device complexity increases

Engineering Contradiction:
Improvedevice functionalityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple control functions into a single integrated control element that can perform switching, dimming, and locking operations. This merging approach maintains device functionality while reducing the number of separate components, thereby simplifying the overall device structure and reducing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control element is designed with multi-functionality, capable of performing multiple operations including switching the drive motor on/off, adjusting light output through dimming, and engaging/disengaging the locking device. This universal design allows one component to replace several specialized components, reducing device complexity while maintaining versatility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a locking device is added to secure the control element, then the reliability is improved, but the device complexity increases

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking device is designed to be automatically engaged or disengaged based on the position of the control element itself. When the control element is in a specific position (such as being pulled out or rotated to a certain angle), the locking mechanism automatically activates or deactivates without requiring separate control inputs. This self-service approach enhances reliability by ensuring the control element is secured when needed while avoiding the complexity of additional control systems.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the control element can be pulled out for easier actuation, then the ease of operation is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveease of operationVSAvoidmanufacturing precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The control element is designed with dynamic positioning capability, allowing it to be pulled out or extended from the handle body for easier actuation. This dynamic configuration provides mechanical advantage and improved ergonomics for the user. The design incorporates tolerances and adjustment mechanisms that accommodate manufacturing variations, ensuring reliable operation without requiring extremely tight manufacturing precision.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4434687B1Hand-held work device with a guide tube
Publication Date: 2026.04.29 ANDREAS STIHL AG & CO KG
  • EP4434687B1 patent drawingFigure 1~2
  • EP4434687B1 patent drawingFigure 3~5
  • EP4434687B1 patent drawingFigure 6~9

AI summary

A hand-held tool comprises a drive motor (4), at least one tool (23) driven by the drive motor (4), and at least one handle (5). A first control element (11), a second control element (12), and a third control element (13) are pivotally mounted on the handle (5). The first control element (11) is designed to control the drive motor (4) and is pivotally mounted about a first pivot axis (14). The second control element (12) is pivotally mounted about a second pivot axis (15). A locking device (30) is provided which, in a release position (31) of the locking device (30), releases the first control element (11) for operation of the drive motor (4) and, in a locked position (32) of the locking device (30), locks the first control element (11) for operation of the drive motor (4).The locking device (30) is adjustable between the release position (31) and the locked position (32) via the second control element (12). The third control element (13) is pivotally mounted about a third pivot axis (16). In its actuated position (45), the third control element (13) holds the second control element (12) in its actuated position via a retaining element (24). The retaining element (24) is pivotally mounted about a fourth pivot axis (25). The second pivot axis (15) lies in a plane (28) that is perpendicular to the fourth pivot axis (25).