Uses and Benefits of Barrel Springs
Barrel springs are a type of convex compression spring which can produce linear or nonlinear force. The top and bottom outer diameters of barrel springs are smaller than the center outer diameter.
Most barrel springs need to be custom made, our specialty spring division, Acxess Spring, is dedicated to creating all types of custom springs, including barrel compression springs. These springs vary based on wire diameter, diameter of the spring, and overall shapes.
The barrel springs we manufacture, range from a wire diameter of 0.006 inches to 0.100 inch. Barrel springs can be telescoping or non-telescoping in nature. Telescoping refers to a situation where the smaller coils go inside the larger coils when the spring is compressed. In the case of a spring that will be exposed and needs to have a certain aesthetic look we can also offer the option to quote a different finish on your barrel spring. Some of the options we can quote are zinc plating, gold zinc plating and nickel plating.
Barrel Springs Prevent Buckling
When a compression spring is 4 times as long as it is wide the spring will buckle when compressed. On a normal compression spring this can be prevented by placing the spring over a shaft or in a hole. If this is not a possibility you can use a barrel spring. The shape of a barrel spring, wider in the center than on the ends, allows for the pressure to be distributed differently and gives stability to a longer compression spring. You can see an example of this on the picture to the right. If you are interested to test this theory out, take a compression spring that is 4 times (or more) as long as it is wide and compress it down with your hand. When the pressure elevates too much the spring will buckle under the pressure causing the center of the spring to protrude outward and eventually shoot away from underneath the pressure.
Solid Height Reduction
A compression spring will produce force in a linear direction, which is appropriate for most designs where a barrel spring can be used. The issue with compression springs, however, is design restrictions can cause a solid height conflict. For example you need a spring to have a force that requires multiple coils, when compressed these coils will bind on top of each other to the point they can no longer be compressed. This is referred to as solid height, or compressed height. This may be an issue in your design. An alternative in the case is to use a barrel spring that will telescope the smaller coils on the top and bottom of the spring into the larger coils in the center of the spring, thus reducing the solid height.
Industries That Use Barrel Springs
Some of the industries that use barrel springs are the automotive industry, toy industry, drinking bottles where powder will be mixed with water, and the furniture industry.