Variable Thread Lead Screws for Bond Stress Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing screw and threaded rod connections fail to achieve reliable and robust bonding under high loads due to maximum bond stress peaks, which can lead to failure, especially in applications like wooden structures where load distribution is critical.
Innovation Solution
A method and design for screws or threaded rods with a variable thread lead that creates internal stress, which counteracts the bond stress caused by external loading, reducing peak bond stress and enhancing the failure load capacity by optimizing the thread shape to match expected stress distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screw or threaded rod with constant thread lead is used, then the manufacturing is simple and standardized, but the bond stress distribution is uneven with maximum peaks that reduce connection reliability under high loads
Solution Approach 1:
The patent applies local quality by varying the thread lead along the longitudinal direction of the screw or threaded rod. Different sections of the thread have different lead values, creating a non-uniform thread pitch distribution. This allows the bond stress to be distributed more evenly along the connection length, reducing maximum stress peaks and improving connection reliability without requiring completely new fastener types
Solution Approach 2:
The patent changes the thread lead parameter from a constant value to a variable value along the longitudinal direction. By adjusting the thread lead parameter at different positions, the patent optimizes the bond stress distribution to reduce maximum stress peaks. This parameter variation approach maintains manufacturing feasibility while significantly improving connection performance under high loads
2Strength
If the thread lead is varied to optimize bond stress distribution, then the maximum bond stress peaks are reduced and load capacity increases, but the manufacturing complexity and production costs increase
Solution Approach 1:
The patent varies the thread lead parameter along the longitudinal direction to optimize bond stress distribution. This parameter change reduces maximum bond stress peaks and increases failure load capacity. The invention balances manufacturing complexity by providing specific guidance on thread lead variation ranges that achieve stress optimization while remaining producible with standard or slightly modified manufacturing processes
Solution Approach 2:
The patent applies local quality by implementing different thread lead values in different longitudinal sections of the screw or threaded rod. This allows optimization of bond stress distribution in critical high-stress regions while maintaining simpler thread configurations in lower-stress areas, thereby balancing manufacturing complexity with improved strength performance
3Reliability
If a variable thread lead design is implemented, then the bond stress distribution becomes more uniform and connection reliability improves, but the device complexity and design requirements increase
Solution Approach 1:
The patent applies local quality by varying the thread lead in specific longitudinal sections where stress concentration occurs. This targeted approach creates a more uniform bond stress distribution and improves connection reliability without requiring complete redesign of the entire thread structure, thus limiting the increase in device complexity to only the necessary regions
Solution Approach 2:
The patent changes the thread lead parameter to achieve more uniform bond stress distribution. By carefully selecting the range and pattern of parameter variation, the patent improves reliability while controlling design complexity through practical guidance on acceptable thread lead variation ranges and patterns
Data Source
AI summary
Method for reinforcing a component and/or for introducing force into a component using a screw or a threaded rod, wherein the screw or threaded rod has a thread with a variable thread lead, which thread creates an internal stress distribution, which is suitable to reduce at least one maximum in the bond stress occurring under loading of the component.