Pretensioning Screw Diameter Ratio for High Compressive Force
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Solution Overview
Problem
Existing pretensioning elements with pressure screws have limited bracing forces, restricting their application range and effectiveness, especially under high industrial loads.
Innovation Solution
A pretensioning element pressure screw design featuring a fine thread with a favorable diameter ratio between threaded and unthreaded sections, combined with a hexalobular or external hexagonal engagement mechanism, allows for high compressive force transmission and efficient torque application, enabling broader application and reduced material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the outer diameter of the unthreaded shank section is increased to transmit high compressive forces, then the force transmission capability is improved, but the material usage and device complexity increase
Solution Approach 1:
The patent applies parameter changes by optimizing the diameter ratio between the unthreaded shank section and threaded section to a specific range (0.95-1.5). This precise parameter optimization allows the unthreaded section to transmit high compressive forces effectively while minimizing material usage. The fine thread design with shallow thread depth also contributes to this optimization by maintaining a large core diameter for torque transmission while using less material compared to standard threads.
Solution Approach 2:
The patent implements local quality by providing different structural characteristics in different sections of the pressure screw. The threaded section has a fine thread design with specific pitch and depth optimized for torque transmission, while the unthreaded shank section has a larger diameter optimized for compressive force transmission. This localized optimization of structural properties allows each section to perform its specific function efficiently without unnecessary material usage throughout the entire component.
2Power
If a fine thread with shallow thread depth is used to allow large core diameter for torque transmission, then the torque transmission capability is improved, but the thread strength may be reduced
Solution Approach 1:
The patent applies parameter changes by specifying precise parameters for the fine thread design, including thread pitch, thread depth, and core diameter. These parameters are optimized to achieve the right balance between torque transmission capability and thread strength. The shallow thread depth reduces material removal and maintains a larger core diameter for torque transmission, while the specific pitch and depth ratios ensure sufficient thread strength for the application requirements.
3Loss of substance
If the outer diameter of the unthreaded shank section is optimized to 1.0 times the threaded section diameter for material-saving production, then material usage is reduced, but the compressive force transmission capability may be limited
Solution Approach 1:
The patent resolves this contradiction by defining an optimized parameter range for the diameter ratio (0.95-1.5) rather than a single fixed value. This range allows flexibility to achieve both material efficiency and sufficient compressive force transmission depending on specific application requirements. The lower end of the range (1.0) provides material-saving production, while the upper end allows for enhanced force transmission when needed, with the fine thread design compensating for the reduced shank diameter.
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 design enables the transmission of high compressive forces, increases the range of applicable loads, and reduces moment stresses, allowing for smaller dimensions and lower production costs while maintaining high torque application efficiency.
Implementation Method 1
a threaded section with an outer diameter D extending from its first end 13
Implementation Method 2
The outer diameter dg of the non-threaded shank section 21 corresponds to 1.0 times the outer diameter D of the threaded section 16, thus enabling material-saving production of the preload pressure screw
Data Source
Figure 1~2
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Figure 5~6
AI summary
The invention relates to a pretensioning element pressure screw (11) having a shank (12) with a first end (13) and a second end (14) opposite the first end (13), wherein, proceeding from the first end (13), a threaded section (16) having an outer diameter (D) is provided, and, adjoining the threaded section (16), an unthreaded shank section (21) having an outer diameter (dg) is provided, which extends to the second end (14) of the shank (12). The pretensioning element pressure screw also has an engagement means (26) for the tool, which is provided at the first end (13) of the shank (12). The outer diameter (dg) of the unthreaded shank section (21) corresponds to 1.0 times the outer diameter (D) of the threaded section (16). The invention also relates to a pretensioning element and to a pretensioning screw body element having a plurality of such pretensioning element pressure screws (11).