Rotational and Axial Hammer Sensing for Power Tool Impact Timing

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Solution Overview

Problem

Existing power tools lack precise control over the impact mechanism components, leading to inefficiencies, increased vibrations, and reduced durability due to imprecise timing of hammer and anvil impacts.

Innovation Solution

Implementing sensors to detect the rotational and axial positions of the hammer and anvil within the power tool, allowing a controller to optimize the impact timing and adjust motor operation based on these positions, thereby enhancing energy transfer and reducing vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensors are implemented to detect hammer position, then impact timing precision is improved, but device complexity increases

Engineering Contradiction:
Improveimpact timing precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements feedback by using sensors to detect the position of the hammer and anvil, then using this information to control the motor and optimize impact timing. The controller continuously monitors component positions and adjusts motor operation in real-time to maximize energy transfer and minimize vibrations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces mechanical position-sensing methods with electronic sensors and digital control. Instead of using mechanical linkages or physical switches to detect position, the system uses electronic sensors to detect component positions and a controller to process this information and adjust motor operation.

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

2Productivity

If impact timing is optimized for maximum energy transfer, then productivity is improved, but stress on components increases

Engineering Contradiction:
ImproveproductivityVSAvoidcontact stress
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

The patent applies dynamics by continuously adjusting the impact timing based on real-time detection of component positions. The system optimizes the moment of impact to maximize energy transfer to the fastener while minimizing harmful vibrations and stress on the hammer and anvil. The controller dynamically modifies motor operation to achieve optimal impact conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes operational parameters by adjusting motor speed and timing based on detected component positions. The system modifies the timing and force of impacts to optimize energy transfer while reducing stress on components. This involves dynamically changing the operational parameters of the impact mechanism based on real-time feedback.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If sensor detection is added to monitor component positions, then reliability is improved, but manufacturing cost increases

Engineering Contradiction:
ImprovereliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent implements feedback by using sensors to detect the position of the hammer and anvil, then using this information to control the motor and optimize impact timing. The controller continuously monitors component positions and adjusts motor operation in real-time to maximize energy transfer and minimize vibrations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-diagnosis and self-adjustment by using sensor data to automatically optimize impact timing and detect potential issues. The controller monitors component positions and adjusts operation to prevent damage, reducing the need for external monitoring and maintenance.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3894137B1Power tool component position sensing
Publication Date: 2025.10.22 MILWAUKEE ELECTRIC TOOL CORP
  • EP3894137B1 patent drawingFigure 1
  • EP3894137B1 patent drawingFigure 2
  • EP3894137B1 patent drawingFigure 3

AI summary

Position sensing related to a component within a power tool. The component within the power tool is, for example, a hammer of an impact mechanism and can include one or more sensible features that allow a controller of the power tool to precisely determine the position, speed, and acceleration of the component. One or more sensors can be used to determine the rotational position of the hammer and the axial position of the hammer. The rotational position of the hammer can then be used to calculate, for example, rotational speed and acceleration of the hammer. With precise determinations of the rotational and axial position of the hammer, the controller of the power tool is able to precisely time the impact between the hammer and the anvil to optimize the impact between the hammer and the anvil (e.g., to maximize energy transfer between the hammer and the anvil).