What Spring Technology Do We Use?
From everyday consumer products to industrial equipment, springs are universal in all kinds of machines. Disassemble anything involving a mechanism and chances are, there is spring technology inside. Every spring comes with its own behavioural and design characteristics that must be considered depending on the project.
As spring technology engineering has advanced due to advances in design software, we are better equipped to create sophisticated products that reduce the likelihood of negative applications to performance and reliability to product development projects.
To learn more about the types of spring technology we use every day, read more below.
Types of springs and their applications
The most common way to identify and classify springs is in terms of how load is applied to them. Ordinary spring technology you might be familiar with includes:
l Compression springs – these are designed to operate with a compressive load and can be found in spring mattresses, shock absorbers, retractable pens and mechanical pencils.
l Torsion springs – this type of spring technology is designed to operate with twisting force (torque) in products like mouse traps and clothespins. Torsion springs obey an analogous version of Hooke’s Law (F=k*0, where 0 is an angle).
l Extension springs – these springs are designed to operate with a tensile load, meaning how well they can withstand longitudinal stress without breaking. These can be found in garage door mechanisms, luggage scales and slinkies and can also be referred to as tension springs.
Each of these types of spring technology can be further characterised by the relationship between the force applied to a spring and its resulting displacement. Within these, there are three classes of springs which include constant force, variable rate and linear (also known as constant rate) spring technology.
Constant force springs
Constant force springs which are also known as clock springs require almost the same force, no matter the length of the extension. This type of spring is usually a coiled ribbon of spring steel used in counterbalancing applications such as height adjustment for monitors as well as clocks.
Variable rate springs
This type of spring technology is a cone-shaped compression spring, most commonly found in battery boxes. Variable rate springs don’t have the same spring rate throughout their axial length and have progressive or more abrupt changes in the spring rate.
Furthermore, the fully compressed height can reach as low as one wire diameter whilst having the benefit of being less prone to buckling as well as being laterally stable.
Linear springs
Linear springs obey Hooke’s Law (F=k*x), meaning that the force needed to compress or extend this spring by distance X is proportional to the distance, as long as the force doesn’t exceed the elasticity limit of the spring.
In which case, the ‘K’ in Hooke’s Law is the ‘spring rate’ which stays constant no matter the deflection because they are the same diameter from top to bottom – this is why this type of spring technology is also referred to as constant rate springs.
Linear springs are excellent for applications where a constant load is required such as counterbalances, gym equipment, hairdryers, door closers, electric motors, appliances and other long-motion functions.
Spring manufacturing
Not only can we classify spring technology by how the load is applied to them, but they can also be categorised by how they are manufactured. A spring that comes to the majority of people’s minds is most likely a metal coil spring (also known as a helical spring) – but there are many other types. Even elastic bands can be considered variable rate springs as they hold mechanical energy too.
Flat springs
Flat spring technology comes in a variety of shapes and sizes which need to be treated for shape memory. Examples of coiled flat springs include volute springs and clock springs. Additionally, spring washers and retainer clips are also examples of flat springs.
Flat springs are ideally suitable in applications where there’s limited space or the spring can be used as part of the mounting assembly and can be made for many design applications.
Machined springs
Machined and die spring technology is used for heavy-duty applications and are engineered to have spring characteristics whilst providing precise performance as extensions, lateral transition, compression, torsion or lateral bending spring.
Coil springs
Coil springs function and serve three basic purposes – storing energy to release it, absorbing shock or maintaining a force between two surfaces. If too much force is applied, the spring can be stretched beyond its limit which can cause permanent distortion.
The spiral, coiled shape is easily recognisable which means it can be used to push, pull or support almost anything. Springs that come off the coiling machines don’t have springy properties and need to be heated to a high temperature (500 degrees Fahrenheit or more) to relieve stress before they can be properly shaped.
Molded springs
Plastic or composite springs can be commonly found in corrosive environments like medical and marine applications as well as the food production industry. Due to creep (spring fatigue), they can only be used intermittently. Compared to metal springs, they are relatively new to the space and supply is not as generous.