Servomotor Gearshift Unit for Automatic Hammer Mode Switching

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Solution Overview

Problem

Existing hand-held power tools lack a convenient and reliable method for fully automatic activation or deactivation of the hammer mechanism, requiring manual operation and lacking flexibility in switching between non-impact and impact modes.

Innovation Solution

A hand-held power tool with a drive unit featuring a servomotor that activates the hammer mechanism, allowing for automatic switching between non-impact and impact modes, coupled with a transmission system that enables gear shifting between different operating modes, including screwing, drilling, and percussion drilling, using a switching unit with a servomotor and a position detection system for precise mode control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a manually operable switching element is used to activate/deactivate the percussion mechanism, then the device complexity is reduced, but the ease of operation is worsened due to lack of automatic mode switching

Engineering Contradiction:
Improveautomatic mode switchingVSAvoidswitching unit with servomotor
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The switching unit automatically detects the required operating mode based on the inserted tool type and switches between non-impact and impact modes without manual intervention. The system serves itself by monitoring tool characteristics and autonomously selecting the appropriate operating mode, eliminating the need for manual switching operations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical switching with an automated system that uses a servomotor driven by an actuating motor. This substitution of mechanical manual operation with an automated motor-driven switching mechanism enables automatic mode transitions based on detected tool characteristics.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If manual operation is required for switching between non-impact and impact modes, then the device complexity is reduced, but the productivity is worsened due to additional manual steps

Engineering Contradiction:
Improveoperational efficiencyVSAvoidautomated switching unit
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The switching unit automatically detects the required operating mode based on the inserted tool type and switches between non-impact and impact modes without manual intervention. The system serves itself by monitoring tool characteristics and autonomously selecting the appropriate operating mode, eliminating the need for manual switching operations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary detection of the inserted tool's characteristics before operation begins. By detecting tool type and pre-determining the required operating mode in advance, the system prepares the appropriate mode automatically, eliminating the need for manual switching during operation and improving overall productivity.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If a servomotor is added for automatic hammer mechanism activation, then the ease of operation is improved, but the weight of the moving object increases

Engineering Contradiction:
Improveautomatic hammer activationVSAvoidhand-held power tool weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The patent introduces a switching unit as an intermediary component that includes a servomotor driven by an actuating motor. This intermediary mechanism enables automatic activation and deactivation of the hammer mechanism by translating rotational motion into linear displacement of a switching element, providing automated control while distributing the weight impact across multiple components.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 convenient and safe activation/deactivation of the hammer mechanism and seamless switching between operating modes, enhancing user experience and operational flexibility by automating mode transitions and providing precise control through a user-friendly interface.

Implementation Method 1

The servomotor is designed to convert a rotary movement into a linear movement of the actuatable switching element required to activate or deactivate the hammer mechanism

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

the activation element has an inclined plane for the axial displacement of the at least one deactivation element

Methodology Applied
Scientific EffectInclined plane mechanism: Inclined Plane

Data Source

PatentEP3389946B1Hand-held power tool with a gearshift unit
Publication Date: 2020.02.19 ROBERT BOSCH GMBH
  • EP3389946B1 patent drawingFigure 1
  • EP3389946B1 patent drawingFigure 2
  • EP3389946B1 patent drawingFigure 3

AI summary

In a hand-held power tool with a drive unit for driving a working tool in at least one non-percussive mode of operation, wherein the drive unit comprises a percussion mechanism (260) for the percussive operation of the working tool in an associated percussion mode, and the drive unit is associated with a gearshift unit (205) for shifting the drive unit between the at least one non-percussive mode of operation and the associated percussion mode, the gearshift unit (205) is associated with a servomotor (282) designed to actuate, when it is activated in the non-percussive mode of operation, the percussion mechanism (260) by switching the drive unit from the at least one non-percussive mode of operation into the associated percussion mode.