When researching some of the different types of washers used in the aerospace industry, you may come across lock washers. They are fasteners used to distribute the load of a threaded bolt. Lock washers, however, go one step further. While all washers offer load distribution, lock washers live up to their namesake by “locking” in place. The end result is resistance to loosening.
What Are Lock Washers?
As shown in the adjacent photo, lock washers are circular-shaped fasteners. They are available in different styles. Some of them are split. Known as split lock washers, they are cut or split open. Other lock washers have inner- or outer-facing teeth.
Traditional washers, of course, aren’t available in these same styles. Traditional washers simply consist of a metal ring. They aren’t cut or split open, nor do they feature teeth. These alternative styles allow lock washers to prevent the bolts with which they are used from loosening. Even when exposed to vibrations, bolts will remain in place when secured with a lock washer.
How Lock Washers Work
You might be wondering how lock washers work exactly? While they are available in different styles, they all work in a similar way. When installed, lock washers exert a downward force towards the surface of the object in which they are installed. This force helps to secure the bolt in the respective object so that it doesn’t loosen.
Lock washers are essentially springs. They may not have the same coiled design as standard springs, but their operation is the same. Lock washers can store mechanical energy while simultaneously exerting a force due to this mechanical energy.
Lock washers are typically used with a nut. You can slide a lock washer over the exposed shank of a bolt. You can then secure it with a nut. Twisting a nut onto the shank will cause it to press against the lock washer. The lock washer will then exert a downward force that prevents the bolt from loosening.
Not all washers consist of a solid ring of metal. Some of them are cut or split open, whereas others have inner- or outer-facing teeth. Washers in one of these alternative styles are known as lock washers. Lock washers are designed to protect bolts from loosening. In aerospace applications, bolts are oftentimes exposed to vibrations. Lock washers won’t eliminate vibrations. Nonetheless, they can protect bolts from loosening when exposed to vibrations.