Bolt Tensioning Through a Threaded Washer for Accurate Axial Force Detection
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Solution Overview
Problem
The existing methods for detecting the tightening force of bolts often result in axial force detection errors due to insufficient circumferential length of the thread portion, leading to plastic deformation and inaccurate measurements.
Innovation Solution
A tensioning device that engages the female thread portion with a washer's outer circumferential male thread portion, allowing for accurate axial force detection by applying tension through the washer, which reduces the risk of plastic deformation and enhances measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the tensioning member is threadly engaged with the bolt shaft portion, then the bolt can be tensioned for detection, but the insufficient circumferential length of the thread portion causes plastic deformation and increases axial force detection error
Solution Approach 1:
A washer with a male thread portion is introduced as an intermediary component between the tensioning device and the bolt. The washer's larger diameter provides sufficient circumferential thread length for reliable engagement, preventing plastic deformation while enabling accurate axial force detection through the connection member's female thread portion.
2Reliability
If the bolt shaft diameter is small and extension length is short, then the bolt structure remains compact, but the thread engagement length becomes insufficient leading to detection errors
Solution Approach 1:
The detection system is segmented into separate functional components: the washer provides thread engagement, the connection member provides force transmission and detection, and the bolt provides fastening. This segmentation allows the washer to have sufficient thread engagement length independent of the bolt's dimensions, ensuring reliable detection without requiring extended bolt shaft length.
Data Source
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AI summary
[Problem to be Solved] To reduce an error of an axial force detection or the like by tensioning a bolt with a tensioning device threadly engaged with a part of the bolt, which is different from a shaft portion of the bolt. [Solution] A tensioning device 1 is configured to apply upward tension to a bolt 10 fastened to a fastened member H, and insertedly fitted with a washer 11. A first male thread portion 11a is formed on an outer circumferential surface of the washer 11. The tensioning device includes a connection member 2 having a first female thread portion 21a1 to be threadly engaged with the first male thread portion 11a, a tensioning mechanism 3 for tensioning the connection member 2 in a state where the first male thread portion 11a is threadly engaged with the first female thread portion 21a1, and a tension bearer 4 which is disposed around an outer circumference of the connection member 2, and bears a reaction force applied from the fastened member H in tensioning performed by the tensioning mechanism 3.