Capacitive Grip Sensor Housing for Hand-Held Power Tools
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Solution Overview
Problem
Existing hand-held power tools with capacitive sensors face limitations in sensor geometry, positioning, and wiring complexity, leading to durability issues and increased costs.
Innovation Solution
Integration of capacitive sensor elements made from conductive plastic within the tool's housing, eliminating the need for additional wires and using a printed circuit board for direct connection, with elastic or geometric spring structures ensuring stable contact over varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional PCB technologies and foil connectors are used for sensor elements, then electrical connection is achieved, but wiring complexity and device assembly difficulty increase
Solution Approach 1:
The sensor element is integrated directly into the housing structure, merging the sensor function with the housing. The connecting part of the sensor element is directly connected to the control element without requiring separate cables or wires, thus simplifying the wiring arrangement while maintaining connection reliability
Solution Approach 2:
The housing serves multiple functions: it provides structural support, electrical insulation, and integration of the sensor element. The insulating housing material is used to achieve insulation between the sensor element and outside, eliminating the need for additional insulation components
2Reliability
If sensor elements are mounted separately next to the sensitive surface, then sensor functionality is achieved, but assembly convenience and durability decrease
Solution Approach 1:
The sensor element is integrated into the housing during the housing manufacturing process, combining the sensor mounting function with the housing structure. This eliminates separate mounting steps and reduces assembly complexity while improving connection reliability through direct integration
Solution Approach 2:
The sensor element is pre-integrated into the housing structure during housing manufacturing, before final assembly. The connecting part is already positioned and connected to the control element, eliminating the need for separate wiring and mounting operations during final assembly
3Measurement precision
If conductive plastic with high conductivity is used for sensor element, then sensor sensitivity improves, but electromagnetic compatibility deteriorates
Solution Approach 1:
The resistivity of the conductive plastic is optimized to a specific range (100-10000 Ωcm) to achieve the right balance between sensor sensitivity and electromagnetic compatibility. This parameter optimization allows the sensor to detect capacitive changes while minimizing electromagnetic interference
4Reliability
If traditional wiring methods are used for sensor connection, then electrical connection is achieved, but durability and service life decrease due to cable arrangement faults
Solution Approach 1:
The vulnerable cable and wire connections are completely removed from the system. The sensor element is directly connected to the control element through integrated connecting parts, eliminating the cables that could cause faults and reduce service life
Solution Approach 2:
The sensor element and control element are integrated into a unified structure where the connecting part is directly connected to the control element. This eliminates separate cable connections that are prone to faults, improving durability and service life
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
Simplifies assembly, reduces failure rates, enhances durability, and optimizes costs by integrating capacitive sensor elements with the tool's housing, improving electromagnetic compatibility and sensor sensitivity.
Implementation Method 1
a power switch may be activated, and then a drive unit may be actuated via a switch actuated by a user. A capacitive sensor, for example, is arranged in a gripping part of a power tool and may detect a user's hand on the gripping part.
Data Source
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AI summary
A hand-held power tool, which comprises a housing, in which a drive unit and a control unit for controlling the drive unit are provided, the control unit being designed to have a control element, and at least one capacitive sensor element being provided, wherein the at least one sensor element is integrated in the housing, and comprises a connecting part exposed at an inner side of the housing, and the connecting part is directly connected to the control element. Thus, the at least one sensor element is integrated in the housing, and insulation performance of the power tool housing made of plastic is also used for achieving insulation between the sensor element and the outside. Moreover, the control element is connected between sensor elements, and extra cables or wires are not needed, simplifying a wiring arrangement in the housing; the structure is simple, device assembly is convenient, and faults caused by arranging cables or wires may further be prevented, improving the durability of the power tool.