Regular Tapered Springs
Tapered springs are a type of compression springs that differ in shape from the uniform cylindrical profile of typical helical coil compression springs. Tapered springs are also commonly referred to as Conical Springs because their outer diameter (OD) varies in size from one end to the other, giving the spring its conical shape. The large end of the tapered spring is referred to as the Large OD, while the small end is referred to as the Small OD.
Applications
Conical springs have a compact, telescoping compression profile, a high degree of stability under compression, and a variable spring rate, which together make them well-suited for variable, dynamic vibration loading applications and push-button components and other applications where space is limited, because the tapered coils allow the spring to nest into itself during compression.
Battery contacts in consumer electronics devices are one of the most recognizable deployments of tapered springs. Tapered springs serve as the primary electrical contact between the battery and the device, holding it securely during unpredictable dynamic loads and impacts because their broad base creates a stable, secure connection.
Key Specifications
A tapered spring’s key geometric properties include the Large Outer Diameter (Large OD) and Small Outer Diameter (Small OD), which are the largest and smallest circumferences of the helical coil. Other key tapered spring specifications include spring Material and Wire Diameter.
Furthermore, the Inside Diameter (ID) is critical for tapered springs that fit over a shaft or mandrel, as it represents the diameter of the Small OD’s internal surfaces.
All of these key specifications together dictate the tapered spring’s Maximum Load Capacity, Average Spring Rate, and the height of the tapered spring when fully compressed, denoted as the Solid Height. The solid height of a tapered spring may be as small as the thickness of a single wire diameter.
Benefits
The size difference between the tapered spring’s Large OD and Small OD means that during compression, adjacent active coils fit into each other in a telescoping manner, yielding an extremely compact solid height compared to traditional straight cylindrical helical coil compression springs.
As such, tapered springs are commonly used in space-constrained applications and in those that require additional stability and buckling resistance, as the large base provides good stability during both spring compression and relaxation.
Furthermore, tapered springs have progressive spring rates that increase as the spring is displaced closer to the larger helical coils, a desirable feature for vibration isolation equipment because it provides additional damping at large displacement magnitudes.
Finally, tapered springs can accommodate loads that are not consistent across a single design profile. For example, a tapered spring might be an excellent choice for shock absorption elements in automotive suspension systems because the suspension must be capable of handling a wide range of displacements as would be encountered during driving.