Rotary Impact Tool PCB Sensing for Non-Contact Anvil Detection
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Solution Overview
Problem
Existing rotary impact tools face challenges in accurately detecting and controlling the rotational position and impact frequency of the anvil and hammer components, leading to inefficiencies in torque and speed control.
Innovation Solution
Incorporation of a printed circuit board assembly with sensors to detect anvil rotation and hammer translation, positioned to maintain an axial gap from the anvil to prevent contact and interference, allowing precise control through a controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are positioned close to the anvil for detection, then measurement precision is improved, but the risk of contact and interference increases
Solution Approach 1:
The patent introduces a non-contact sensor (optical or magnetic sensor) as an intermediary to detect anvil rotation without physical contact. The sensor is positioned to face the anvil lug through a gap, using optical or magnetic fields to detect rotational position and impact events, thereby eliminating mechanical contact while maintaining measurement precision
Solution Approach 2:
The patent replaces mechanical contact-based sensing with non-contact sensing mechanisms. Instead of using mechanical switches or contact-based sensors that would interfere with the high-speed impacting components, the invention uses optical sensors or magnetic sensors that detect anvil rotation and hammer impacts through electromagnetic or optical fields without physical contact
2Device complexity
If contact-based sensing is used for detecting anvil rotation, then device complexity is reduced, but measurement reliability deteriorates due to wear and interference
Solution Approach 1:
The patent substitutes mechanical contact-based sensing systems with non-contact optical or magnetic sensing systems. This eliminates wear, friction, and contact interference that would reduce reliability over time, while the optical or magnetic detection methods provide consistent and reliable measurement of anvil rotation and impact events
Solution Approach 2:
The non-contact sensor acts as an intermediary that detects anvil rotation and hammer impacts without being affected by the high-force mechanical environment. The optical or magnetic field-based detection method isolates the sensing mechanism from the harsh operating conditions, improving long-term reliability
3Device complexity
If the printed circuit board assembly is positioned close to the anvil for compact design, then device complexity is reduced, but manufacturing precision requirements increase to avoid contact
Solution Approach 1:
The non-contact sensor design creates a functional gap between the PCB assembly and the anvil that serves as a built-in protective feature. This gap, combined with the use of optical or magnetic fields as intermediaries, allows the PCB to be positioned relatively close to the anvil without risk of contact, reducing overall device complexity while maintaining manufacturing feasibility
Solution Approach 2:
The optical or magnetic detection field acts as an intermediary that allows the sensor to be positioned on the PCB assembly without requiring extremely tight manufacturing tolerances. The non-contact nature of the sensing mechanism provides a buffer zone that accommodates normal manufacturing variations
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 precise control of impact frequency and rotational speed, enhancing the tool's performance and efficiency by accurately measuring and adjusting torque and speed settings.
Implementation Method 1
a printed circuit board assembly including an anvil sensor that is configured to detect rotation of the anvil
Implementation Method 2
a second printed circuit board assembly including a hammer sensor configured to detect at least one selected from a group consisting of: (a) translation of the hammer; (b) rotation of the hammer; and (c) occurrence of an impact between the hammer and the anvil
Implementation Method 3
a drive assembly for converting a continuous torque input from the motor to consecutive rotational impacts upon a workpiece
Data Source
Figure 1
Figure 2
Figure 2A~3
AI summary
A rotary impact tool includes a motor housing, an electric motor supported in the motor housing, and a drive assembly for converting a continuous torque input from the motor to consecutive rotational impacts upon a workpiece. The drive assembly includes an anvil including an anvil lug and a hammer that is both rotationally and axially movable relative to the anvil. The hammer includes a hammer lug for imparting the consecutive rotational impacts upon the anvil lug. The rotary impact tool further comprises a printed circuit board assembly including a sensor that is configured to detect rotation of the anvil. The printed circuit board assembly is spaced from the anvil to define an axial gap therebetween.