What is an Extension Spring?

Extension springs store energy and exert a pulling force between two mechanisms. When mechanisms separate, the extension spring tries to bring them together again. Extension springs use round wire to create a close-wound design with initial tension.

How Extension Springs Work

An extension spring’s ends attach between two mechanisms. The extension springs hooks and loops store and absorb energy. Through hooks or loops, an extension spring provides return force to connected mechanisms.

Tightly wound extension springs typically sit in the no-load position. More stress in the end hooks—as opposed to the spring body—limits the performance of extension springs.

Applications of Extension Springs

Extension springs use a variety of hook or loop end configurations to fit specific functions. Extension spring ends include threaded inserts, extended twist loops, crossover center loops, hooks, expanded eyes, reduced eyes, rectangular ends and teardrop-shaped ends.

Modify the length of hooks and the spring body distance for customized extension spring fits and functions.

Find extension springs in a variety of everyday items, from garage doors to tools to washing machines to toys. The variety in size makes extension springs versatile as they are used in small medical devices and off-road machinery. 

Common applications of extension springs include:

Car interiors and exteriors

Garage door assemblies

Vise-grip pliers

Carburetors

Trampolines

Washing devices

Farm machinery

Toys

Extension Spring Types and Designs

Extension springs use a variety of hook or loop end configurations to fit specific functions. Extension spring ends include threaded inserts, extended twist loops, crossover center loops, hooks, expanded eyes, reduced eyes, rectangular ends and teardrop-shaped ends.

Modify the length of hooks and the spring body distance for customized extension spring fits and functions.

Custom Extension Springs

Hongyi manufactures made-to-order extension springs for OEMs. Our custom spring manufacturing capabilities include:

Extension springs with a wire diameter of .010″ up to .250″A variety of ends, including twist, German hooks, cross center, side loops, flat stock hooks and extended hooks. An array of material types including stainless steel, music wire, hard drawn and more. Custom extension spring designs to match your specific requirements and tensions. We have the expertise and latest equipment to design and manufacture your next extension spring order.