Hand-Held Power Tool Mode-Setting Device with Detachable Coupling

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Solution Overview

Problem

Existing handheld power tools with mode setting devices face complexity in simple and safe operation due to the coupling of torque setting and gear shifting elements, which complicates gear changes and mode settings.

Innovation Solution

A detachable coupling mechanism between the torque setting element and the gear shifting element allows for automatic gear change with a single actuating element, enabling secure and uncomplicated operation by using a pivotably arranged coupling element interacting with a guide track on the housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the torque setting element and gear shifting element are permanently coupled, then the mode setting device is simple in structure, but the gear change operation becomes complicated and unsafe

Engineering Contradiction:
Improvemode setting device structureVSAvoidgear change operation
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The coupling element is designed to dynamically change its state between coupled and decoupled positions. During normal operation, the coupling element remains in the coupled position to transmit torque setting to gear shifting. During gear change, it automatically moves to the decoupled position to allow independent gear selection, thus adapting the system behavior to operational requirements

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The coupling element acts as an intermediary between the torque setting element and the gear shifting element. It mediates the torque setting input by conditionally transmitting it to the gear shifting mechanism - allowing transmission during normal operation but blocking it during gear changes, thus resolving the conflict between operational simplicity and safety

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the torque setting element and gear shifting element are permanently decoupled, then the gear change operation is simple and safe, but the device requires more components and becomes more complex

Engineering Contradiction:
Improvegear change operationVSAvoidmode setting device structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The coupling element merges the functions of torque setting and gear shifting control into a single integrated mechanism. By combining these two control functions through the coupling element, the patent avoids the need for completely separate control systems, thus reducing overall device complexity while maintaining operational simplicity and safety

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If a single actuating element is used for both torque setting and gear shifting, then the operation is simplified, but the coupling between torque setting and gear shifting becomes problematic

Engineering Contradiction:
Improveoperation simplicityVSAvoidcoupling reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The coupling element dynamically adjusts its engagement state based on operational context. It provides reliable coupling during normal torque setting and gear shifting operations, then automatically disengages during gear changes to prevent interference, thus maintaining both operational simplicity and coupling reliability

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3720659B1Hand-held power tool with a mode-setting device
Publication Date: 2023.06.07 ROBERT BOSCH GMBH
  • EP3720659B1 patent drawingFigure 1
  • EP3720659B1 patent drawingFigure 2~3
  • EP3720659B1 patent drawingFigure 4~5

AI summary

The invention relates to a hand-held power tool comprising a housing (110), in which a drive motor (120) and a transmission (150) that can be driven by the drive motor (120) in order to drive an output shaft (205) are arranged, wherein a mode-setting device (160) is provided which has at least one rotatable actuation element (240) for setting an operating mode, a torque-adjusting element (220) for adjusting a torque, and a gear changing element (230) for changing gears of the transmission (150). The torque adjusting element (220) and the gear changing element (230) are releasably coupled together during a gear changing process.