Electric Torque Wrench With Isolated Strain Sensing
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Solution Overview
Problem
Conventional electric ratchet wrenches are limited by mechanical energy output and suffer from inaccurate torque readings due to strain gauge placement near the head portion, which is prone to collision and vibration, affecting structural integrity.
Innovation Solution
An electric torque wrench design with a strain sensor unit positioned away from the head portion, using a strain shaft and strain gauge to measure torque, integrated with a connection sleeve and moment arm sleeve for improved structural integrity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the strain gauge is placed near the head portion to detect torque force, then the torque reading accuracy is improved, but the strain gauge is affected by collision and vibrations which reduces reliability and may damage the strain gauge
Solution Approach 1:
The wrench is divided into functional segments: the head portion for contact with fasteners, the strain gauge portion for measurement, and the handle for operation. The strain gauge is positioned on the handle away from the head portion, separating the measurement function from the high-stress contact zone while maintaining measurement accuracy through proper mechanical coupling.
Solution Approach 2:
A strain gauge is introduced as an intermediary element that indirectly measures torque by detecting deformation in the handle or connecting structure, rather than placing it directly at the head portion. This intermediary approach allows torque measurement while protecting the strain gauge from direct exposure to collision and vibration.
2Measurement precision
If the strain gauge is placed near the head portion to detect torque force, then the torque reading accuracy is improved, but the deformability of the strain gauge weakens the structural integrity of the wrench
Solution Approach 1:
The wrench structure is segmented into a rigid head portion for applying force to fasteners and a separate measurement zone where the strain gauge is positioned on the handle. This segmentation allows the head to maintain high structural integrity while the handle provides the necessary deformability for strain gauge operation.
Solution Approach 2:
Different parts of the wrench have different mechanical properties optimized for their specific functions: the head portion is designed with high strength and rigidity for force application, while the handle or connecting structure has controlled deformability to enable strain gauge measurement without compromising overall structural integrity.
3Ease of operation
If a conventional electric ratchet wrench is used, then the tool is electrically powered and easy to operate, but the torque output is limited by the mechanical energy that can be provided by the electric motor
Solution Approach 1:
The patent merges the advantages of electric power (ease of operation, consistent power delivery) with the capabilities of a torque wrench (accurate torque measurement and control). The electric motor drives the mechanism while the strain gauge provides torque feedback, creating a hybrid tool that combines both functionalities.
Solution Approach 2:
The electric torque wrench serves multiple functions: it provides powered operation like an electric ratchet wrench, measures torque accurately like a torque wrench, and can control torque output through the strain gauge feedback system. This multi-functionality allows the single tool to replace both the electric ratchet wrench and the manual torque wrench.
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
Enhances torque reading accuracy and structural integrity by isolating the strain gauge from collision and vibration, allowing for precise torque measurement and increased mechanical power output.
Implementation Method 1
the strain gauge detects torque force via deformation and the strain gauge is place near the head portion which is the part that contacts the nuts and bolts, collision and vibrations may affect the accuracy of the torque readings
Data Source
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AI summary
An electric torque wrench includes a ratchet head unit (1), a wrench body unit (2), a drive output unit (3), an electric motor unit (4), a strain sensor unit (5), and a control unit (6). The wrench body (2) unit includes a connection sleeve (21) connected to the ratchet head unit (1). The drive output unit (3) includes a ratchet head driver (31). The electric motor unit (4) includes an electric motor (41) driving rotation of the ratchet head driver (31). The strain sensor unit (5) is mounted in the wrench body unit (2), and outputs a torque reading of an external force. The control unit (6) includes a display module (61) for displaying the torque reading, and a battery module (63). The strain sensor unit (5) is located between the electric motor (41) and the battery module (63).