Nuts self-locking - reliable connection without Grover washers and lockwashers

Spontaneous unwinding of threaded joints entails the danger of premature failure of a wide variety of machines and mechanisms. The Grover washer effectively prevents this undesirable phenomenon, but it has its drawbacks. Firstly, it is an extra assembly unit, and secondly, it can simply be forgotten by another disassembly.

How to do without Grover puck

The old way is to screw the lock nut, that is, one more nut, wrapped over the main one. This method is effective, but not always applicable, especially in cases where the weight of a machine or mechanism is important, for example, in aviation or space-rocket technology.

In order to improve the performance of almost all branches of engineering, nuts were invented self-locking, that is, those with which vibration and other mechanical vibrations are at fault.

There are several ways to achieve this result.

Different types of self-locking nuts

The first method of improving the stability of the threaded joint is to make the mounting parts so that the nuts self-locking during screwing are tested on the windings with elastic deformations, which is provided by the so-called "interference", i.e., a positive tolerance providing increased friction during tightening.

Similar deformations can be achieved also with a multi-step cutting of the nut and bolt. With each next turn, this difference will increase the force required to disassemble the assembly, which eliminates arbitrary self-development.

There is also a nut self-locking with a nylon ring, through which the mechanical braking of any of their course after screwing. The elastic polymer insert also acts as an additional damper, i.e., a damper for mechanical vibrations, which also positively affects the reliability of the threaded joint.

The tool for solving the problem is also a thickening in the lower part with a special notch creating an increased friction after it is pressed against the surface of the fixed part. Such self-locking nuts are easy to recognize, they differ significantly in appearance from their usual hexahedral counterparts.

Original solutions

There are other ways to prevent undesirable and untimely unscrewing. For joints that do not experience significant mechanical loads during operation, steel -stamped self-locking nuts can be used, which create an increased resistance in the reverse motion due to the springing properties of the material of manufacture.

It is also possible to use additional gear rims fixed to the bottom of the fastener. Strengthening friction at the points of contact, the protrusions securely fix its position.

Despite the variety of shapes, any fastener is manufactured according to state and international standards, including a self-locking nut. GOST 5915-70 and DIN 985 are the documents regulating their size (they come with metric and inch threads) and the material (ordinary, alloy or stainless steel).