Coaxial Shear Wrench Layout for Balanced Torque and Tip Ejection
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Solution Overview
Problem
Shear wrench tools cause user fatigue due to the need to counteract the moment of force from the weight of the motor and transmission, and existing designs do not efficiently manage the removal of the sheared bolt tip.
Innovation Solution
A shear wrench tool with an electric motor, planetary gear transmission, and an output section where the first and second output sleeves rotate in opposite directions, balanced by a handle positioned at the tool's center of gravity, and an ejection mechanism for removing the sheared bolt tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a handle is provided at the rear of the tool, then the tool structure is simplified, but user fatigue increases due to the need to counteract the moment of force from the weight of the motor and transmission
Solution Approach 1:
The patent positions the handle at the center of gravity of the tool, creating a balanced structure where the handle acts as a counterweight to offset the moment of force generated by the motor and transmission components. This balance point positioning eliminates the need for users to exert additional counter-moment force with their wrists, thereby reducing user fatigue while maintaining structural simplicity
2Volume of moving object
If the motor, transmission and output section are arranged axially in sequence, then the tool achieves a compact coaxial design, but the removal of the sheared bolt tip becomes more difficult
Solution Approach 1:
The patent segments the output section into first and second output sleeves that can rotate in opposite directions relative to each other. This segmentation allows the second output sleeve to be independently manipulated for bolt tip removal while the first output sleeve continues to engage the nut, enabling easy removal of the sheared bolt tip without compromising the compact axial arrangement
Data Source
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AI summary
A shear wrench tool comprising an electric motor having a motor output shaft, a transmission having a plurality of planetary gear stages and an output section having first and second output sleeves the first output sleeve being configured for mating with a nut and the second output sleeve being configured for mating with a tip of a bolt to be sheared, wherein the electric motor is configured to provide torque via the transmission to the output section for causing the first and second output sleeves to be rotated in opposite directions relative to each other in use, and wherein the electric motor, the transmission and the output section are arranged in an axial sequence one after the other such that the first and second output sleeves circumferentially extend around the same axis that the motor output shaft and the planetary gear stages rotate about in use, thereby providing that the motor output shaft, the planetary gear stages and the first and second output sleeves are coaxial.