Shear Wrench Pre-Shear Control for Tension Bolt Adjustment
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Solution Overview
Problem
Existing shear wrench tools cannot be easily removed from tension control bolts and nuts without shearing the bolt tip due to high friction, making it difficult to adjust the position of workpieces after initial tightening.
Innovation Solution
A shear wrench tool with a DC brushless motor and controller that allows for a pre-shear mode, where the tool can tighten nuts without shearing the bolt tip, enabling easy removal and adjustment of workpieces before permanent fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shear wrench tool is used to tighten the nut on the tension control bolt, then the fastening torque is achieved, but the tool cannot be removed from the bolt and nut due to high friction
Solution Approach 1:
The patent applies preliminary action by introducing a breakaway tip that is designed to shear off at a predetermined torque level. This tip is attached to the fastening tool and transfers torque to the nut during tightening. Once the predetermined torque is reached, the tip shears off, automatically releasing the tool from the workpiece. This preliminary design of a sacrificial torque-transfer element solves the problem of tool removal after achieving the required fastening torque.
Solution Approach 2:
The patent extracts the torque transfer function from the main tool body by using a separate, removable breakaway tip. This tip is designed to be consumed or removed after serving its purpose of transferring torque. By separating the torque transfer mechanism into a disposable tip, the main tool is freed from the workpiece after the tip shears off, enabling easy removal and reuse of the expensive tool while the inexpensive tip is discarded.
2Reliability
If the nut is fully tightened on the tension control bolt, then the workpiece is permanently fixed, but the workpiece position cannot be adjusted
Solution Approach 1:
The patent applies partial action by using a breakaway tip with a predetermined shear torque that is set to a specific value. The tip is designed to transfer torque up to this predetermined level and then fail, preventing excessive torque application. This allows the user to achieve sufficient tightening for permanent fixation without over-tightening, and the controlled failure of the tip provides a clear indication that the fastening process is complete.
Solution Approach 2:
The patent changes the physical state of the breakaway tip from intact to sheared off as a result of reaching the predetermined torque. This parameter change (from connected to disconnected) provides a clear visual and physical indication that the fastening operation is complete. The tip transitions from a torque-transfer state to a failed state, signaling to the operator that the required torque has been achieved and the tool can be removed.
3Reliability
If the breakaway tip is designed to shear at high torque, then permanent fixation is achieved, but the tool cannot be removed for workpiece adjustment
Solution Approach 1:
The patent applies preliminary action by pre-setting the breakaway tip with a specific shear torque value that corresponds to the required permanent fixation torque. The tip is manufactured with this predetermined failure point, so when the fastening operation reaches this torque level, the tip automatically shears off. This preliminary design eliminates the need for the operator to estimate or calculate the exact torque required for permanent fixation, providing a reliable and repeatable fastening process.
Solution Approach 2:
The patent uses a disposable breakaway tip that is inexpensive compared to the main fastening tool. The tip is designed to be consumed after a single use, shearing off at the predetermined torque to release the tool. This allows the expensive tool to be removed and reused for adjusting workpiece positions, while the inexpensive tip is discarded. The disposable nature of the tip enables multiple adjustment cycles without replacing the entire tool, reducing overall time and cost.
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 the user to install and adjust workpieces correctly by allowing partial tightening of nuts on tension control bolts, facilitating precise alignment before final fixation.
Implementation Method 1
a DC brushless motor (112) and a controller (126) which is configured to control operation of the DC brushless motor (112)
Data Source
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AI summary
A shear wrench tool comprising: a motor; a transmission operatively connected to the motor; a first socket arranged to engage a tip of a bolt to be sheared; and a second socket arranged to engage a nut threaded on the bolt; wherein the first and second sockets are operatively connected to the transmission and rotate in opposite directions relative to each other when the motor provides a torque to the transmission; and wherein the motor can be driven in both forwards and reverse directions.