Captive Panel Fastener Installation Head Assembly
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Solution Overview
Problem
Existing manual tools for installing captive panel fasteners in aircraft require excessive and uncontrolled manual pressure, leading to repetitive motion injuries, inconsistent fastener flaring, and potential tool malfunction due to work hardening during multiple strokes.
Innovation Solution
A head assembly for fastener installation tools that applies a predetermined outer axial compressive force to an anvil for flaring and a predetermined inner axial tensile force to a bushing for retention, allowing for a single controlled stroke installation of captive panel fasteners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual pressure is applied to flare the fastener end, then the fastener can be installed, but the pressure is uncontrolled and inconsistent leading to work hardening and potential malfunction
Solution Approach 1:
The patent transforms the manual, uncontrolled pressure application into a controlled, predetermined force application through the spring mechanism. The spring constant and pre-compression distance are designed to provide the exact force needed for proper fastener flaring without excessive pressure that would cause work hardening and malfunction.
Solution Approach 2:
The spring mechanism automatically applies the correct amount of pressure through its inherent elastic properties. The system self-regulates the force applied to the fastener end, eliminating the need for operator judgment and ensuring consistent, appropriate pressure application without manual intervention.
2Ease of operation
If longer handles are added to increase mechanical advantage, then less manual pressure is required, but access to tight airframe spaces is prevented
Solution Approach 1:
The patent replaces the manual mechanical advantage system (long handles requiring two-handed operation) with an elastic spring mechanism that stores and releases energy automatically. This substitution eliminates the need for long handles while still providing sufficient force through the spring's elastic potential energy.
Solution Approach 2:
The spring mechanism operates through periodic compression and expansion cycles. The operator compresses the spring during insertion, storing energy, and then releases it during the flaring action. This periodic energy storage and release provides the necessary force without requiring long handles or two-handed operation.
3Reliability
If multiple strokes are used to ensure proper flaring, then the fastener can be securely installed, but the fastener undergoes work hardening that can cause breakage
Solution Approach 1:
The spring mechanism is pre-compressed during fastener insertion, storing elastic energy in advance. When the fastener reaches its final position, the spring automatically releases this stored energy to apply the exact amount of force needed for proper flaring in a single controlled action, eliminating the need for multiple strokes that would cause work hardening.
4Adaptability or versatility
If hand-operated tools are used for repetitive fastener installation, then flexibility is maintained, but repetitive motion injuries occur
Solution Approach 1:
The spring mechanism performs the force-intensive flaring action automatically through its elastic recovery, requiring minimal operator effort. The operator simply inserts the fastener and releases the trigger, allowing the spring to complete the installation work. This eliminates repetitive strain on the operator's hands and forearms while maintaining the flexibility of hand-held tool 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
The solution enables consistent and controlled installation of captive panel fasteners with reduced risk of injury and tool failure, ensuring proper flaring and retention with a single tool stroke, improving access and efficiency in tight spaces.
Implementation Method 1
a spring having an undeformed position and a pre-compressed position a predetermined distance apart for applying a predetermined outer axial compressive force to the anvil
Implementation Method 2
a tension member for applying a predetermined inner axial tensile force to the bushing
Data Source
AI summary
An installation head for use with captive panel fasteners. The head is adapted for mounting onto a conventional fastener installation tool that can apply a predetermined outer axial compressive force distributed about a predetermined inner axial tensile force. The pulling head transfers the outer axial compressive force to an inner axial compressive force delivered to a flaring anvil, while at the same time transferring the inner axial tensile force to an outer axial tensile force delivered to an internally threaded bushing that accommodates the threaded shank of a captive panel fastener. Using the tool and the installation head to apply the predetermined axial tensile and compressive forces, captive panel fasteners can be reliably installed using a single tool stroke.