Dual-Lever Load Indicator for Fastener Bore
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Solution Overview
Problem
Current fastener load indicating technologies are cumbersome, require skilled labor, are often unreliable, and are not suitable for smaller conventional fastener configurations, as they need enlarged heads or external components that are prone to environmental damage and calibration issues.
Innovation Solution
A dual-lever load indicating system is integrated within the fastener, where a first lever is connected at a lower internal pivot and a second lever at an upper internal pivot, providing amplified visual indication of load on a scale, reducing the required bore size and depth, and allowing for internal, sealed, and durable installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single pivot lever is used for visual load indication, then load amplification is achieved, but the bore depth and diameter must be significantly increased
Solution Approach 1:
The single lever system is segmented into two separate levers: a first lever that responds to fastener elongation and a second lever that provides the visual indication. This segmentation allows each lever to be smaller and fit within conventional fastener bores while collectively achieving the required amplification effect.
Solution Approach 2:
The indication mechanism is repositioned from an external location to an internal location within the fastener head. The second lever rotates within the bore to move an indicator along a scale, utilizing the internal three-dimensional space of the fastener head to achieve compact amplification without requiring external components.
2Ease of manufacture
If external indicators are used for load monitoring, then visual indication is provided, but the indicators are prone to environmental damage and calibration issues
Solution Approach 1:
The load indication function is merged with the internal structure of the fastener itself. The indicator system is integrated within the sealed fastener head, combining the structural integrity of the fastener with the indication mechanism to protect against environmental factors while maintaining visual accessibility through a window in the fastener head.
3Device complexity
If conventional fasteners are used without load indication, then simplicity is maintained, but monitoring of clamp load status is not possible
Solution Approach 1:
The fastener performs self-monitoring through the integrated lever system that automatically responds to changes in clamp load status. The levers are mechanically coupled to the fastener body, so any elongation or relaxation automatically moves the indicator without requiring external sensors, power sources, or complex electronics.
4Measurement precision
If enlarged fastener heads are used to accommodate single lever indicators, then load indication is achieved, but compatibility with smaller conventional fasteners is lost
Solution Approach 1:
The indication function is segmented across two levers with different functions, allowing the first lever to be compact and fit within small fastener bores, while the second lever provides the visual amplification through rotational movement within the same confined space.
Solution Approach 2:
The system utilizes rotational movement of the second lever within the fastener head to achieve visual amplification without requiring increased bore depth. The indicator moves along an arc path visible through a window, providing clear load indication within the constraints of conventional fastener dimensions.
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 enables continuous, accurate, and easy-to-calibrate visual monitoring of clamp load status during tightening and throughout the fastener's life, reducing the need for external equipment and skilled labor, while being compatible with smaller fastener configurations and resistant to environmental factors.
Implementation Method 1
the levers are configured and positioned within a fastener and cooperate to indicate the load on the fastener by amplification of the elongation experienced by the fastener
Data Source
AI summary
A load indicating insert visually displays fastener loading during tightening and use of a fastener. First and second levers are positioned by a connective cartridge substantially within a fastener bore to provide a compound. amplified indication of loading as a function of the elongation or deformation of the fastener. The first lever is connected at an internal pivot point of a cartridge with a lower end resting on an abutment within the fastener bore. As the abutment moves the first lever during elongation, the second lever moves relative to a visual loading scale. As the fastener is loaded and unloaded, varying elongation of the fastener causes displacement of the abutment and movement of the indicator back and forth along the load indicating scale.