Hand-Held Power Tool Housing With Pressure-Based Speed Control
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Solution Overview
Problem
Hand-held power tools with high single impact energy and low dead weight face challenges in applying and engaging tools to a workpiece due to reaction forces and vibrations, which are not effectively addressed by existing technologies.
Innovation Solution
A hand-held power tool design featuring a decoupled housing with movable elements and a magnetic field sensor to detect spacing, allowing for motor speed adjustment based on user pressing force, thereby improving tool application and reducing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the hand-held power tool has high single impact energy and low dead weight, then the tool is more maneuverable and easier to handle, but the tool experiences greater reaction forces and vibrations that make application and engagement problematic
Solution Approach 1:
The housing elements are made movable relative to each other through the magnetic coupling mechanism, allowing the system to dynamically adapt to reaction forces during operation. The first housing element can move independently from the second housing element, enabling the tool to absorb and manage impact reactions without transmitting all forces to the user's hand, thus maintaining ease of operation while preserving low dead weight.
Solution Approach 2:
The magnetic field acts as an intermediary coupling mechanism between the two housing elements. This magnetic coupling provides a flexible connection that transmits necessary structural forces while allowing relative movement to accommodate reaction forces. The magnetic field sensor serves as an intermediary detection system that monitors the spacing and enables controlled response to operational conditions.
2Object-affected harmful factors
If the housing elements are mechanically decoupled to reduce vibrations, then the handle experiences fewer vibrational movements, but the structural integrity and force transmission may be compromised
Solution Approach 1:
The patent replaces traditional mechanical coupling (screws, bolts, rigid connections) with a magnetic field-based coupling system. This substitution allows the housing elements to remain structurally integrated through magnetic attraction while permitting controlled relative movement. The magnetic coupling provides both structural integrity and vibration isolation, as the magnetic field can transmit forces while allowing the housing elements to move independently under impact loads.
Solution Approach 2:
The magnetic coupling strength can be dynamically adjusted by changing the spacing between the housing elements, which in turn changes the magnetic field intensity. When vibration reduction is needed, the elements move apart slightly, reducing magnetic coupling strength and allowing independent movement. When structural integrity is needed, the elements come closer, increasing magnetic coupling strength. This dynamic parameter adjustment resolves the contradiction between vibration reduction and structural integrity.
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 easier and more intuitive operation by adjusting motor speed according to user pressure, reducing tool slippage and vibrations, and ensuring reliable engagement with the workpiece.
Implementation Method 1
a magnetic field sensor for detecting a spacing between the first housing element and the second housing element
Data Source
AI summary
The hand-held power tool (1) includes a housing (8), which has a first housing element (9) and a second housing element (10), wherein the first housing element (9) and the second housing element (10) are decoupled from one another and are movable relative to one another. The hand-held power tool (1) furthermore includes a tool holder (2) and a motor (4) for rotational and/or percussive driving of the tool holder (2). Furthermore, the hand-held power tool (1) has a magnetic field sensor (16) for detecting a spacing (L) between the first housing element (9) and the second housing element (10). Moreover, the hand-held power tool (1) includes a control device (18) for setting a motor speed of the motor (4) in accordance with the detected spacing (L).