Constant Force Spring


Constant-force springs are a very special variety of extension spring.

They consist of a spiral of strip material with built-in curvature so that each turn of the strip wraps tightly on its inner neighbor.

When the strip is extended (deflected) the inherent stress resists the loading force, just as in a common extension spring, but at a nearly constant (zero) rate.

The constant force spring is well suited to long extensions with no load build up. In use, the spring is usually mounted with the ID tightly wrapped on a drum and the free end attached to the loading force, such as in a counterbalance application. The relationship can be reversed, however, with the free end mounted stationary and the spring itself providing the working force, as with carbon brushes in electrical apparatus.


Be sure to allow at least 1.1/2 cols of material on the drum at full extension. The spring ID will wrap tightly on the drum so that in most applications no fastening method on the drum is required.


Type 301 stainless steel.

Specialty Springs


Custom Products

We manufacture and do custom design springs according to your requirements. To inquire, please contact / email us .

List of products that we custom design and manufacture:

Compression, torsion, extension, flat, garter, serpentine, power, volute, constant-force and torqued coil springs

Spring Washers 
Belleville, slotted, curved, dished, wave, star and finger washers

Metal Parts 
Engineered stampings, wire forms, square and shaped wire parts, snap rings, spring-tension fasteners

Assemblies/Special Springs 
Complex wire and strip forms assembled from purchased and in-house manufactured parts