Captive Fastener Pin Retraction for Thread-Safe Locking
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Solution Overview
Problem
Captive fasteners have not kept pace with advancements in fastening systems, lacking durability and efficient mechanisms for locking pin operation.
Innovation Solution
A captive fastener design featuring multiple components, including a primary body, actuator, locking pins, biasing system, bushing, and actuator biasing member, where the actuator displaces to retract the locking pin from an extended to a retracted position, allowing relative rotation without interference with the thread pattern, and returns to bias the pin back to the extended position upon force removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the locking pin remains in extended position to maintain locking, then the fastener provides secure connection, but the thread pattern becomes damaged or interfered with
Solution Approach 1:
The locking pin is designed to be dynamically positionable between extended and retracted states. The actuator mechanism allows the pin to move from an extended position (where it engages the second component for secure connection) to a retracted position (where it clears the thread pattern). This dynamic positioning resolves the contradiction by enabling the system to switch between locking and non-interfering states as needed.
2Object-affected harmful factors
If the actuator is designed to retract the locking pin to avoid thread interference, then the thread pattern is protected, but the mechanism complexity increases
Solution Approach 1:
The actuator mechanism is integrated directly into the first component body, merging the actuation function with the existing structural elements. The biasing member is combined with the actuator assembly, eliminating the need for separate mounting structures. This integration reduces overall complexity while still providing the necessary pin retraction capability to protect the thread pattern.
Solution Approach 2:
The biasing member automatically returns the actuator to its initial position after the pin has been retracted, eliminating the need for manual reset mechanisms or additional control systems. The system self-regulates the pin position based on the presence or absence of applied force, reducing complexity while maintaining functional reliability.
3Reliability
If a biasing member is added to return the actuator to initial position, then the locking reliability is improved, but the device complexity increases
Solution Approach 1:
The biasing member creates a self-regulating system that automatically returns the actuator to its initial locked position when external force is removed. This self-service mechanism ensures reliable locking without requiring external control systems, motors, or additional actuators, thereby improving reliability while minimizing the increase in device complexity.
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
Enhances durability and operational efficiency by ensuring reliable locking and unlocking mechanisms without damaging the thread pattern, improving the overall performance and longevity of the fastener.
Implementation Method 1
The actuator biasing member returns the actuator to the actuator first position upon removal of the predetermined force
Implementation Method 2
allowing the biasing member to bias the pin away from the retracted position
Data Source
AI summary
A captive fastener having multiple components selectively biased to improve durability, including a primary body, an actuator, a plurality of locking pins, a biasing system, a bushing, and an actuator biasing member. Application of a predetermined force to an actuator proximal end longitudinally displaces the actuator from an actuator first position to an actuator second position and forces a cam leading edge against a biasing member to retract a pin from an extended position to a retracted position that does not interfere with a thread pattern formed in the fastener. The actuator biasing member returns the actuator to the actuator first position upon removal of the predetermined force allowing the biasing member to bias the pin away from the retracted position.