Nut Locking Assembly With Uniform Threads for Vibration Resistance
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Solution Overview
Problem
Existing locking devices with reverse-direction threads face difficulties in assembly and locking due to limited angle of rotation, making them difficult to mount and dismantle, and are prone to unlocking under vibrations.
Innovation Solution
The locking device features identical and constant thread pitches for all threads and tappings, with increased radial clearances and standardized ISO triangular profiles, allowing for a wider range of rotation and a visual marking system for correct locking, along with a positive locking mechanism using a washer for enhanced security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different pitches are used between the thread of the assembly 'ring/nut' and the threads of the 'screw/nut' and 'screw/ring' assemblies, then the ring can rotate relative to the nut over a fairly wide angle, but the assembly becomes difficult to mount and lock
Solution Approach 1:
The patent applies parameter changes by using identical and constant thread pitches for all threads and tappings (first, second, and third tappings), which resolves the contradiction between achieving wide rotation angle and ease of mounting. This uniform pitch parameter allows the ring to rotate freely relative to the nut while maintaining simple assembly procedures, eliminating the complexity introduced by varying pitches in prior art solutions.
2Adaptability or versatility
If finer or wider pitches are used, then the angle of rotation is increased, but the locking device becomes difficult to assemble and lock due to the limited angle constrained by the smallest pitch length
Solution Approach 1:
The patent changes the pitch parameter from variable (as in prior art) to identical and constant across all threads and tappings. This uniform pitch design eliminates the constraint where the smallest pitch limits the rotation angle, allowing full rotational freedom while simplifying the assembly process and reducing device complexity.
3Reliability
If the thread flanks are in contact, then the locking device is secured, but the device is prone to unlocking under vibrations
Solution Approach 1:
The patent extracts the locking function from the thread flank contact mechanism and implements it through a separate positive locking mechanism using a locking element (such as a locking washer or tab). This separation allows the thread flanks to maintain contact for load bearing while the dedicated locking element prevents vibration-induced unlocking, thereby improving reliability without compromising security.
Data Source
AI summary
The invention relates to a locking device (300) comprising: a shaft (24) comprising a first thread (22); and a nut (12) and a ring (13) to be assembled on the shaft; the nut comprising a first inner thread (18) defining a first radial clearance with the first thread of the shaft; the nut further comprising a second inner thread (20) in the opposite direction to the first inner thread, the ring (13) comprising a second thread (40) defining a second radial clearance with the second inner thread of the nut; the ring comprising a third inner thread (38) defining a third radial clearance with the first thread of the shaft. The inner threads and the first and second threads have an identical and constant thread pitch; and each of the second and third radial clearances is greater than the first radial clearance.