Impedance Control Device for Power Tool Safety
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Solution Overview
Problem
Existing safety devices for motorized tools, such as electric secateurs and circular saws, face challenges with discomfort from wired connections and risks of cutting these connections, while also struggling to reliably detect user contact with moving blades to prevent injuries.
Innovation Solution
A control device with a manually actuated control member featuring impedance meter interfaces, including insulated manual contact electrodes, to detect user presence and prevent accidental contact with the tool's active member by triggering an emergency stop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wired connections are used to detect user contact with the tool, then safety detection capability is improved, but user comfort deteriorates and connection reliability worsens due to cutting risks
Solution Approach 1:
The patent extracts the safety detection function from external wired connections and relocates it directly into the tool's control device. The impedance meter interface and contact electrodes are integrated into the control member, eliminating the need for separate wired connections between conductive clothing and the tool, thereby maintaining safety detection capability while improving user comfort and connection reliability
Solution Approach 2:
The control member is designed to serve multiple functions: it acts as both the operating control interface for tool activation and as the impedance meter interface for safety detection. The contact electrodes on the control member detect user contact while the control member itself operates the tool, combining safety and operational functions in a single component
2Reliability
If contact electrodes are placed on the control member, then detection reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the contact electrodes with the control member structure. The first and second contact electrodes are positioned on opposite sides of the control member, utilizing the existing control member geometry rather than adding separate detection components. This integration maintains detection reliability while minimizing increases in device complexity
Solution Approach 2:
The control member simultaneously serves as the operating interface for tool control and as the detection interface for safety monitoring. By making the control member multi-functional, the patent avoids adding separate detection devices, thereby maintaining simplicity while achieving reliable detection
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
The solution provides a more ergonomic and reliable safety mechanism that effectively prevents injuries by detecting user contact and automatically stopping the tool, reducing discomfort and connection risks.
Implementation Method 1
an impedance meter interface sensitive to a contact of a user with the control member, including a first manual contact electrode and a second manual contact electrode
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5C
AI summary
The invention relates to a control device (10) for a power tool and a power tool (12) provided with the control device. The control device (10) comprises i - an operation control interface (128) which is provided with a manually operated controller (130), - an impedance-measuring safety interface (131), wherein the impedance-measuring interface comprises a first manual contact electrode (132) and a second manual contact electrode (134) which are electrically isolated from each other, and wherein the manual contact electrodes (132, 134) are provided on the controller (130) and extend over a manual bearing surface of the controller. The invention is suitable for controlling and ensuring the safe use of power tools, especially electrical tools, such as pruning shears.