Rotary Fastener Torque Limiting Stop Element
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Solution Overview
Problem
Existing rotary fasteners lack a mechanism to consistently and independently prestress components with a specified connection force, often requiring specialized mounting means and risking overtightening or insufficient bracing force.
Innovation Solution
A rotary fastener design featuring a stop element that can be connected to a threaded shank in a form-fitting or non-positive manner, allowing for a defined torque threshold that limits the connection force, ensuring the bracing force remains within a maximum value by enabling relative rotation between the stop element and the threaded shaft when excessive torque is applied, and incorporating an axial stop to prevent axial movement limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rotary fastener is screwed in completely without torque limitation, then the connection force between components increases, but the risk of overtightening and component damage increases
Solution Approach 1:
The patent incorporates a stop element with a defined torque threshold that预先 limits the maximum connection force before overtightening can occur. This preliminary action prevents component damage by establishing a safety mechanism that activates during the fastening process itself, rather than requiring post-assembly inspection or adjustment.
Solution Approach 2:
The stop element provides real-time feedback during the screwing process by mechanically limiting torque transmission when the defined torque threshold is reached. This feedback mechanism allows the assembly process to self-regulate, preventing excessive force application and ensuring optimal connection force without requiring external monitoring or control systems.
2Reliability
If a torque limitation mechanism is added to the rotary fastener, then overtightening is prevented, but the device complexity increases
Solution Approach 1:
The stop element is integrated directly into the rotary fastener structure, merging the torque limitation function with the fastening mechanism itself. This consolidation eliminates the need for separate torque control devices or assembly means, achieving reliable overtightening prevention while maintaining simple fastener construction.
Solution Approach 2:
The stop element automatically activates when the defined torque threshold is reached, providing self-regulating torque limitation without requiring external control systems, specialized assembly tools, or complex mechanisms. The fastener serves its own torque control function through the inherent mechanical design of the stop element connection.
3Strength
If the stop element is firmly connected to the threaded shank, then the connection force is maximized, but the ability to release at defined torque is lost
Solution Approach 1:
The connection between the stop element and threaded shank is designed with dynamic characteristics that allow it to behave differently under different torque conditions. During normal operation, the connection provides sufficient strength for load-bearing, but when the defined torque threshold is exceeded, the connection allows relative rotation to occur, enabling torque release and preventing overtightening.
Solution Approach 2:
The frictional connection parameters between the stop element and threaded shank are specifically designed to change behavior at the defined torque threshold. The friction force maintains the stop element firmly connected during normal operation, but releases at the precise torque level needed to limit connection force, providing both strength and torque release capability through parameter-based control.
4Ease of operation
If the rotary fastener is designed for tool-independent assembly, then ease of operation improves, but control over connection force decreases
Solution Approach 1:
The rotary fastener with integrated stop element performs its own torque control function without requiring specialized assembly tools or externally controlled assembly means. The defined torque threshold is built into the fastener itself through the stop element connection, allowing anyone to achieve precise connection force control through simple manual or automated screwing operations.
Solution Approach 2:
The stop element provides inherent feedback during assembly that automatically limits connection force to the defined maximum value. This feedback mechanism works regardless of the assembly method used, ensuring consistent connection force control whether assembled by hand, power tool, or automated system, while maintaining ease of operation.
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 design ensures a tool-independent, overtightening-proof connection force that is consistently optimal, preventing accidental detachment and allowing for secure fastening of components with varying thicknesses, while maintaining a controlled bracing force between the first and second components.
Implementation Method 1
due to the frictional forces occurring on the contact surfaces between the stop element and the at least one component, a the stop element is generated relative to the threaded shaft decelerating force
Data Source
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AI summary
The present invention relates to a rotary fastener (10) for installing a first component (12) on a second component (14), comprising a threaded shaft (16) and a abutment element (18), which can be or is connected to the threaded shaft (16) for conjoint rotation, wherein the installed rotary fastener (10) produces a connecting force between the abutment element (18) and the first component (12) and/or between the abutment element and the second component (14). According to the invention, the abutment element (18) can be or is connected to the threaded shaft (16) in a form- and/or force-fitting manner in such a way that the connection between the abutment element (18) and the threaded shaft (16) can be released at a defined torque, wherein the connecting force is limited by the defined torque, and wherein the defined torque is greater than a torque threshold value.