Bolt Head Tensioning Assembly for Axial Force Detection
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Solution Overview
Problem
Existing methods for detecting and maintaining the tightening force of bolts after assembly are inadequate, as they primarily focus on the male thread portion and neglect axial force detection from the bolt head side, leading to potential loosening and increased risk of fatigue fracture.
Innovation Solution
A tensioning device that applies upward tension to a bolt through a connection member with a first male thread on the bolt head, utilizing a tensioning mechanism with a tension rod, bearing, and rotation mechanism, and a tension bearer to detect and maintain axial force, ensuring the bolt is tensioned from the head side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the male thread portion of the bolt protruding from the upper surface is subjected to tension to detect the transition point of the spring constant, then the tightening force can be detected, but the axial force detection from the head side of the bolt cannot be performed
Solution Approach 1:
The invention divides the bolt into two functional parts: the original male thread portion for fastening and a newly added first male thread portion on the bolt head for tensioning. This segmentation allows independent functions to be performed at different locations, enabling both tightening force detection and axial force detection from the head side simultaneously.
Solution Approach 2:
The invention adds a new dimension to the bolt structure by forming the first male thread portion on the outer circumferential surface of the bolt head, which is a different spatial location from the traditional male thread portion. This dimensional addition enables force application and detection from the head side without interfering with the original fastening function.
2Ease of operation
If a connection member with female thread portion is engaged with the first male thread portion on the bolt head, then the bolt can be tensioned from the head side, but the device complexity increases
Solution Approach 1:
The connection member is designed with dual functionality: it engages with the first male thread portion on the bolt head for tensioning operations and incorporates a second male thread portion that can engage with corresponding female threads. This multi-functionality allows a single component to perform multiple tasks, reducing the need for additional specialized parts and thereby limiting the increase in device complexity.
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
This solution allows for accurate detection and maintenance of axial force on the bolt, reducing the risk of loosening and improving the reliability of the fastening system by ensuring consistent tensioning force, thereby preventing fatigue fractures.
Implementation Method 1
a first male thread portion to be threadly engaged with a first female thread portion formed on an inner circumferential surface of a connection member hollow portion
Implementation Method 2
a second male thread portion formed on an outer circumferential surface of a convex portion... a second female thread portion to be threadly engaged with the second male thread portion
Implementation Method 3
a bearing which rotatably supports the tension rod around a vertically extending shaft portion
Implementation Method 4
a tensioning mechanism which tensions the bolt via the connection member while having the first male thread portion threadly engaged with the first female thread portion
Data Source
Figure 1
Figure 2(a)
Figure 2(b)
AI summary
[Problem to be Solved] To provide a tensioning device capable of tensioning a bolt from a bolt head side while suppressing increase in the number of components. [Solution] A tensioning device 1 is configured to apply upward tension to a bolt 10 fastened to a fastened member H. A first male thread portion 12a is formed on an outer circumferential surface of a head 12 of the bolt 10. 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 12a, a tensioning mechanism 3 for tensioning the bolt 10 via the connection member 2 in a state where the first male thread portion 12a 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.