Cam-and-Groove Coupling Retention in Unlocked Position
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Solution Overview
Problem
Conventional cam-and-groove couplings fail to securely retain the male part when the locking arm is in the unlocked position, leading to potential fluid spillage and safety risks due to low friction, and existing modifications can complicate manufacturing and weaken the coupling over time.
Innovation Solution
A modified cam-and-groove coupling design featuring a female part with a cylindrical annular wall and a male part with a circumferentially formed groove and longitudinally recessed channels, allowing the cam to slide along the groove and channels to retain the male part in both locked and unlocked positions, with optional stop and alignment markings for secure engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional cam-and-groove coupling is used with locking arm in unlocked position, then the coupling structure is simple, but the male part may accidentally withdraw due to low friction retention
Solution Approach 1:
The groove on the male part is segmented into multiple sections: a first groove section for cam engagement in the locked position, and a second groove section that provides retention in the unlocked position. This segmentation allows the groove to perform different functions at different operational states without adding complex external components.
Solution Approach 2:
The groove is designed with varying radial depths, creating a three-dimensional profile with a first groove section at a first radial depth and a second groove section at a second radial depth. This dimensional variation enables the cam to engage differently at different radial positions, providing both locked and unlocked retention functions.
2Reliability
If pin and channel modifications are added to retain male part, then retention reliability improves, but manufacturing complexity increases and stress concentrations are created
Solution Approach 1:
The groove structure serves multiple functions: it provides cam engagement in the locked position, retention in the unlocked position, and guidance during insertion and withdrawal. By making the groove multi-functional, the design eliminates the need for separate pins and channels, reducing manufacturing complexity while maintaining reliability.
Solution Approach 2:
The invention merges the retention function (previously requiring separate pins or channels) with the existing groove structure. The groove is redesigned to incorporate both locking and retention features, combining multiple functions into a single integrated component that reduces overall device complexity.
3Reliability
If pin and channel are added to improve retention, then male part retention improves, but the coupling may deform or weaken with repeated use
Solution Approach 1:
The groove has different radial depths at different sections, creating local variations in engagement quality. The first groove section provides deep engagement for locking, while the second groove section provides shallower engagement for retention. This local quality variation optimizes both functions without requiring additional components that could weaken the coupling.
4Device complexity
If cam engages groove only through friction, then the coupling structure is simple, but fluid pressure or weight can overcome friction and cause separation
Solution Approach 1:
The groove is segmented into a first groove section for primary locking engagement and a second groove section for secondary retention engagement. This segmentation creates multiple engagement points that collectively provide sufficient retention force to counteract fluid pressure and weight without increasing structural 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
The design ensures the male part is securely retained in the female part in both locked and unlocked positions, preventing accidental separation and enhancing safety and durability by maintaining engagement without additional stress concentrations.
Implementation Method 1
the male part is retained in the female part only by relatively low friction between the two parts
Data Source
AI summary
A coupling device for fluid lines includes a female part having a rotatable locking arm with a cam, and a male part defining a longitudinal channel and a circumferential groove on its external surface, The male part is inserted into the female part by rotating the locking arm to its unlocked position, aligning the longitudinal channel with the cam, and sliding the cam within the longitudinal channel. The male part is locked into the female part by rotating the cam within the circumferential groove away from the longitudinal channel, and rotating the locking arm into its locked position so that the cam protrudes further into the circumferential groove. Even when the locking arm is rotated to its unlocked position, the cam engages the circumferential groove to retain the male part within the female part unless the cam is rotated within the circumferential groove into alignment with the longitudinal channel.