Constant Force Springs (NEG'ATOR)

Constant Force Springs
How it Works
The NEG'ATOR constant force spring represents the most basic, yet most versatile, type of constant force extension spring. 

It is a prestressed flat strip of spring material which is formed into virtually constant radius coils around itself or on a drum.  When deflected, the spring material straightens as it leaves the drum. This straightened length of spring actually stores the spring’s energy through its tendency to assume its natural radius.

The Material
For high quality force springs Hunter Spring supply constant force springs made from 301 High Yield Stainless Steel. Other materials including Elgiloy, Inconel, or high-carbon steel can be used upon request for custom applications.

Key Features
- Low force gradient over entire deflection range
- Extremely long linear extensions possible
- Maximum force generated at initial deflection
- Permits smaller package size due to inherent compact size and light weight
- A variety of materials can be used
- Negative force or negative torque gradient achievable

Standard or Custom Springs
Hunter Spring can supply standard or custom constant force spring designs. Please click to view our Standard Spring Design Guides below.

Fatigue Life 20,000 Cycles Minimum
Fatigue Life 13,000 Cycles Minimum
Fatigue Life 2,500 Cycles Minimum

Our constant force springs can also be customized to have a negative force or negative torque gradient. For applications where limited space is a concern, springs can be wound together in a laminated assembly to multiply output force with minimal impact on spring size and fatigue life. 

Use the constant force spring design worksheet to specify your requirements and allow our Application Engineers to provide you with a design to meet your needs.

We invite you to consult us. We may well be able to formulate a custom solution that will surprise you with its efficiency and versatility.


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