Definition: A helical spring who’s coils are open thus having pitch in between them.
Open coil helical springs are known as compression springs. There are several types of compression springs and they are identified by the customization of the coil diameters within the body; meaning that some types of compression springs have different shapes due to the coil diameters within their body being different. The different types of open coil helical springs are conical springs, barrel springs (concave), and barbell springs (convex). Magazine springs can also be considered open coil springs but since their coils are oval or rectangular shaped, they are not considered helical. The different open coil helical spring types specified above may take part in many applications. Below you will be provided with the open coil helical spring types and specifications on what they are used for and in which applications you might be able to find them.
Compression springs are the most common and economical type of spring. Their coils are helical and they have a cylindrical shape which allows them to be installed into round holes or over shafts. You are able to find this type of open coil spring in medical devices such as auto-injectors as well as every day devices like a ball point pen.
Conical springs are coil springs whose coils form a tapered shape since the coil diameters are reduced/increase toward the other end of the spring. These springs may be designed to perform a telescope effect which incredibly reduces solid height. They also provide stability when you have a spring with a high slenderness ratio. You may find these springs in battery compartments. They are great for connectivity and, due to the telescope effect, you’re able to completely insert the battery.
Barrel springs are open coil compression springs with adjusted diameters. These springs’ coils are larger towards the center, giving the spring a convex barrel shape. They are used in applications which require for the spring to have stability or to reduce the solid height. You might see them in home appliances for they make great handles. Barbell Springs, on the other hand, are springs whose coil diameters decrease towards the center. They’re also used to reduce solid height and to provide stability.