Conical extension springs

Conical extension springs are specialized helical springs featuring tapered coils (a cone shape), designed to resist pulling forces in applications with limited space or a need for a progressive spring rate. This unique geometry allows for a compact solid height when fully compressed and provides enhanced stability.
Design and Function
The core function of a conical extension spring is to provide tension, similar to a cylindrical extension spring, but with key differences in performance characteristics.
Progressive Spring Rate: Due to the varying coil diameters, conical springs typically have a non-linear or progressive spring rate. This means the force required to stretch the spring increases as it extends, as different diameter coils engage sequentially.
Compactness and Telescoping: The tapered design allows the smaller diameter coils to nest or "telescope" within the larger ones under load. This results in a very low compressed height, which is an advantage in designs with limited axial space.
Enhanced Stability: The conical shape provides greater lateral stability and resistance to buckling under load compared to straight cylindrical springs, particularly beneficial in dynamic applications.
End Types: Like cylindrical extension springs, they feature various end configurations such as machine loops, crossover center loops, or threaded inserts for versatile attachment options.
Materials
Material selection is based on the operating environment, load demands, and temperature requirements. Common materials include:
High Carbon Steel (e.g., Music Wire): A common, economical choice offering high strength and durability, often used in high-stress applications in dry environments.
Stainless Steel (e.g., Type 302, 316, 17-7PH): Provides excellent corrosion resistance and performs well over a wide temperature range, making it suitable for medical, marine, or food processing applications.
Alloy Steels (e.g., Chrome Silicon): Offers superior strength, toughness, and fatigue resistance for heavy-duty and high-stress environments, such as automotive suspensions.
Specialty Alloys (e.g., Inconel, Beryllium Copper): Used for specific needs like non-magnetic properties, high electrical conductivity, or enhanced performance in extreme temperatures.
Common Applications
Conical extension springs are used in specialized applications where their unique properties offer distinct advantages over traditional springs.
Automotive Industry: Key components in suspension systems, seat adjustment mechanisms, and clutch mechanisms for vibration dampening and shock absorption.
Aerospace Engineering: Employed in latching systems, release mechanisms, and landing gear components where stability, reliability, and compact design are critical.
Medical Devices: Found in compact, precision-sensitive equipment such as autoinjectors, infusion pumps, and surgical tools.
Consumer Electronics: Their compact size makes them ideal for push buttons and battery contacts in everyday electronic devices.
Industrial Machinery: Used in presses, valves, and various load-bearing mechanisms for energy absorption and precise motion control.