Hydraulic Foundation Bolt Tensioner with Split Nut and Automatic Retraction
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Solution Overview
Problem
Conventional tensioning systems for foundation bolts are cumbersome, time-consuming, prone to accidents, and difficult to use on long bolts, often resulting in damage and inefficiency due to the need for multiple hydraulic jacks and manual threading, which can lead to variability in tension and potential injuries.
Innovation Solution
A novel foundation bolt tensioner featuring a cylindrical outer body with a sliding annular inner body and a split nut system that allows for efficient hydraulic tensioning, automatic retraction, and a threading ring for easy nut threading, reducing the need for manual effort and minimizing damage risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional tensioning systems with multiple hydraulic jacks and rigid plates are used, then foundation bolts can be tensioned, but the installation becomes cumbersome, time-consuming, and prone to accidents
Solution Approach 1:
The tensioning system is divided into modular components: a tensioning device with hydraulic cylinder, a separate reaction nut, and a foundation bolt interface. This segmentation allows each component to be optimized independently and simplifies installation by eliminating the need for multiple separate jacks and rigid plates, directly resolving the contradiction between reliability and complexity
Solution Approach 2:
The invention merges the functions of multiple hydraulic jacks, rigid plates, and reaction nuts into a single integrated tensioning device. The hydraulic cylinder directly engages the reaction nut which in turn engages the foundation bolt, combining what were previously separate components into one unified system that reduces installation complexity while maintaining tensioning reliability
2Reliability
If conventional tensioners are used on long foundation bolts, then tensioning can be applied, but manual threading of the reaction nut along the entire bolt length becomes particularly time-consuming
Solution Approach 1:
The reaction nut is pre-positioned on the foundation bolt at the optimal location before tensioning begins. The tensioning device is designed to engage this pre-positioned nut directly, eliminating the need to manually thread the nut along the entire length of the long foundation bolt. This preliminary positioning dramatically reduces threading time while maintaining the ability to apply reliable tension
Solution Approach 2:
The reaction nut serves as an intermediary component between the hydraulic cylinder and the foundation bolt. By engaging the nut rather than threading it along the bolt, the system uses this intermediate element to transfer force efficiently without requiring time-consuming manual threading operations, thus resolving the time loss issue while preserving tensioning capability
3Force
If foundation bolts are tensioned using conventional methods, then adequate tension can be achieved, but variability in jack installation and force generation may damage the rigid plate, bolt, or both
Solution Approach 1:
The tensioning device incorporates a feedback mechanism where the hydraulic cylinder's force application is directly coupled to the reaction nut engagement with the foundation bolt. This direct coupling provides immediate feedback on the actual tension being applied, allowing for precise control that prevents over-tensioning and eliminates the variability that caused damage in conventional multi-jack systems
Solution Approach 2:
The system is designed to be self-regulating through the direct mechanical coupling between the hydraulic cylinder, reaction nut, and foundation bolt. The geometry of the engagement surfaces and the hydraulic pressure control work together to automatically maintain safe tension levels, eliminating the need for external monitoring and prevention of the variability-induced damage that plagued conventional systems
4Reliability
If tensioning installations are made to handle long foundation bolts, then adequate tensioning is possible, but asymmetrical installation may cause one jack to disengage, resulting in damages and injuries
Solution Approach 1:
The tensioning device is designed with asymmetrical engagement features that adapt to the specific geometry of the foundation bolt and reaction nut interface. This controlled asymmetry ensures stable engagement even when installation conditions vary, preventing the disengagement that occurs in symmetrical multi-jack systems and thereby improving both effectiveness and safety
Solution Approach 2:
The single tensioning device is designed with universal engagement capabilities that work effectively with foundation bolts of various lengths and configurations. The reaction nut and hydraulic cylinder interface is designed to maintain stable engagement across different installation scenarios, eliminating the asymmetrical disengagement problems that arise in conventional multi-jack systems and improving overall operational safety
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
The solution significantly reduces the time and effort required to tension foundation bolts, enhances safety by minimizing manual handling and potential damage, and ensures consistent tensioning across multiple bolts, making the process more efficient and safer for operators.
Implementation Method 1
a spring-actuated inner body for automatic retraction
Implementation Method 2
efficient hydraulic tensioning
Data Source
AI summary
A tensioner for tensioning foundation bolts generally used in securing large utility towers is provided. The tensioner generally comprises a hollow outer body through which the foundation bolt can extend. The lower end of the body, which is adapted to abut onto the foundation surface from which the bolt extends, is provided with an opening allowing access to a foundation nut threaded onto the foundation bolt. The upper end of the outer body slidingly receives therein an inner body with which it defines an annular hydraulic piston, the inner body being configured with a seat portion for receiving and engaging a split nut mounted to the foundation bolt. Upon providing hydraulic fluid to the tensioner, the hydraulic piston urges the split nut, engaged to the foundation bolt, upwardly, thereby tensioning the foundation bolt. The load in the bolt is then maintained by threading down the foundation nut until it abuts onto the foundation surface.