Union Nut Anti-Loosening Lock Ring Mechanism
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Solution Overview
Problem
Existing member joints, such as pipe and shaft joints, face issues with union nut loosening due to corotation during relative rotation, leading to complications in fixation and release, size enlargement, and durability concerns, especially under strong rotating forces.
Innovation Solution
A member joint design featuring a union nut with a lock ring and pinching pieces, where the lock ring has inwardly extending lock pawls that are elastically deformed to engage with projections on the nut, preventing loosening by pinching the pawls against the nut's trailing surface, and allowing easy detachment by sliding over the projections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a union nut is used to connect two members allowing relative rotation, then the connection is simple and allows rotation, but the union nut loosens due to corotation during rotation
Solution Approach 1:
The lock pawl is preliminarily positioned to engage with the projection on the first member before rotation occurs. This preliminary engagement prevents the union nut from corotating during relative rotation, eliminating the loosening problem while maintaining rotation capability
Solution Approach 2:
The lock pawl acts as an intermediary element between the union nut and the first member. It transfers the locking function from the union nut to a dedicated component, allowing the union nut to remain simple while providing reliable loosening prevention through the lock pawl's engagement with the projection
2Reliability
If a connecting pin is used to fix the union nut to prevent loosening, then loosening is prevented, but fixation and release become complicated
Solution Approach 1:
The lock pawl is designed as a movable component that can be elastically deformed. During normal operation, it automatically engages with the projection to prevent loosening. During release, it can be pushed by the pinching piece to disengage, providing dynamic adaptation between locking and releasing states without complicating the overall structure
Solution Approach 2:
The lock pawl automatically engages with the projection when the union nut is tightened, providing self-locking functionality. The elastic deformation of the lock pawl enables automatic engagement without requiring additional fixing operations, simplifying both fixation and release processes
3Reliability
If a ratchet gear structure is used to prevent loosening, then loosening is prevented, but the structure size enlarges
Solution Approach 1:
The complex ratchet gear mechanism is extracted and replaced with a simplified lock pawl-projection engagement system. The lock pawl engages with a simple projection on the first member, providing loosening prevention without requiring the intricate gear teeth structure, thereby maintaining a compact joint size
Solution Approach 2:
The locking mechanism transitions from a gear-based system to a pawl-based system with different geometric parameters. The lock pawl's inclination angle and elastic deformation characteristics enable effective locking with much smaller dimensions compared to ratchet gear teeth, reducing the overall joint volume
4Adaptability or versatility
If the lock pawl is designed to pass over projections during rotation, then rotation is allowed, but durability concerns arise under strong rotating forces
Solution Approach 1:
The lock pawl is preliminarily engaged with the projection to counteract the corotating force before it can cause loosening. By providing preliminary anti-action through the locking engagement, the system prevents the harmful corotation effect that would otherwise subject the lock pawl to repeated stress cycles and reduce its durability
Solution Approach 2:
The lock pawl is preliminarily positioned to engage with the projection, creating a stable locking state before rotation occurs. This preliminary engagement prevents the union nut from corotating, thereby eliminating the repeated engagement-disengagement cycles that would compromise the lock pawl's durability over time
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 effectively prevents union nut rotation in the loosening direction without using stop pins, simplifying fixation and release, maintaining structural integrity, and enhancing durability by dispersing load and reducing wear, thus ensuring reliable connection and relative rotation without enlarging the joint size.
Implementation Method 1
an inner periphery of the lock ring is provided with an inwardly extending lock pawl which is pressed by the projection when the lock ring is rotated so as to be elastically deformed and pass over the projection
Data Source
AI summary
A member joint, in which a great rotating force is inevitably transmitted to a union nut connecting two members at the time of relatively rotating both the members, is structured such as to reliably carry out corotation prevention of the union nut, without complicating fixation of the nut and releasing of the fixation and without causing enlargement in size and deterioration of durability of a connecting portion. In a member joint (10) connecting a first member (1) and a second member (2) by pinching a flange (6) provided in the second member (2) with respect to the first member (1) by a union nut (3), an outer periphery of the first member (1) is provided with a projection (7) having a leading surface (7a) and a trailing surface (7b), a lock ring (4) is rotatably attached to an open leading end portion of the union nut (3), an inner periphery of the lock ring (4) is provided with a lock pawl (9) which can pass over the projection (7) by being elastically deformed, the union nut (3) is provided with a pinching piece (8) which is engaged with the lock pawl (9), and a leading end side of the lock pawl (9) is pinched between the pinching piece (8) and the trailing surface (7b) when the union nut (3) screwed into a screwing end point rotates by itself in a loosening direction, whereby loosening of the union nut (3) is prevented.