A retaining ring is a unit of hardware that is designed to fit around a circular object, such as a pipe or tube. Once the ring is fastened to the object, it can be used to hold an item at a certain location along the length of the pipe, preventing it from sliding along the pipe's length. Retaining rings can also be used to fasten an object to a pipe, or to fasten the pipe itself in place, such as to a wall or ceiling. They are frequently used with plumbing pipes, but can also be found in vehicles, computers, tools and most kinds of machinery. These units are also known as snap rings, wire rings or circlips depending on the region and application.
Buyers can select from several different types of retaining rings depending on the project at hand. An E-ring has an open circle design, and is used in place of a closed retaining ring when space or access in limited. For example, an E-ring can be slid onto a pipe that is installed in the corner of a room, where two sides of the pipe are not accessible. This type of retaining ring gets its name from its open shape, which resembles the letter "E." Screws or bolts may be used with this type of ring to help hold it in place.
When the entire pipe or object is accessible, a closed retaining ring can be used. These rings may be completely closed in a loop, or shaped like a spiral, with overlapping ends. A closed retaining ring is often installed by sliding the ring over one end of the pipe, though some may be snapped on at different sections along the length of the pipe.
When compared to other types of fasteners, retaining rings are often considered fairly simple and easy to install. They are snapped or slid in place without the use of specialized tools, though care must be taken to use the right size ring for each specific application. To improve fit, the ring is often installed in a special groove, which is cut around the diameter of the pipe or object. A retaining ring that fits well into a groove is said to have good "cling." When the ring is not fit to the pipe, it will fit loosely and may even spin around, resulting in poor cling.
While size is an important consideration when selecting retaining rings, there are a number of other factors that should also be taken into account. Buyers must decide if they need an internal retaining ring, which fits inside a pipe or circular object, or an external ring, which fits around the outside of an object. One must also determine the load and tension that the ring will be subjected to. Thicker rings can typically withstand higher forces and loads, while thinner rings are for lighter loads and more delicate applications.