A washer is a structural component used for fastening components of a structure. It is shaped like a small metal disc and has a hole in the center. It distributes the load of threaded fasteners to the nut and screw. It find many uses including use as a pre-load indication device, vibration reducing device, and a locking device. At times, it finds use as a spacer function.
The material used to make washers varies. So, one may have washers made of plastic, metal., rubber, and fiber. Other classifications include D-shaped, C-Washers, FAE washers, fender washers, shoulder and torque washers. The usual classification of these is plain, spring, and locking washers.
Structure of washers –
The plain washer is flat with a central hole. Its normal use is to transfer load from a screwed fastening. You can see all the offerings they have at the website of the Plain Washer Manufacturers. One may also use a plain washer when the hole is a larger diameter than the fixing nut. In this category we have the fender washer that is a flat washer with large outer diameter and a small inner hole. These are used with sheet metal so there is even distribution of the load. Since they are most commonly used in automobile fenders, they get the name fender washers.
One interesting type of washer is the spherical washer. This is a self-aligning nut. It has a one-radiused surface that must be used in conjunction with a mating nut. It will self-adjust to several degrees when there is a misalignment between the parts. Another flat washer is the penny washer. This is used in the UK and got its name because of its size that is equal to that of a penny.
Belleville washers have a conical shape. When they get deformed they give an axial thrust. They also go by the name of cupped spring washers and conical washers. See all specifications of this type on the website of the Spring Washers Manufacturers. The curved disc spring is just like the Belleville washer but it is curved only in one direction. So it has four points of contact. They only give a light pressure when deformed. Wave washers have a wave in the axial direction that gives a spring pressure when deformed. Again, wave washers do not give much force when deformed. In Germany, at times they find a use as a lock washer but it is not the preferred choice.
Shape of a Spring Washer
Under locking and spring washers, we have the split washer. Otherwise called a spring lock washer, it is made of a ring split at one point. It remains bent into a helical shape and it exerts spring force between the head and the substrate. This maintains the head hard against the substrate. It also keeps the bolt head hard against the nut causing more friction and resistance to rotation. Spring washers have a left-hand helix. So, they are ineffective on left hand threads and hardened surfaces.
Rubber and fiber washers are used in pipes for blocking the flow of water. They are used there because they have good capacity to stop water and they are not corrosive when they contact water.
A washer is a structural component used for fastening components of a structure. It is shaped like a small metal disc and has a hole in the center. It distributes the load of threaded fasteners to the nut and screw. Washers find many uses including use as a pre-load indication device, vibration reducing device, and a locking device. At times, it finds use as a spacer function.