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Springs - What is a Negator Constant Force Spring

The Neg’ator extension spring represents the most basic, yet most versatile, type of constant force spring. It is a prestressed flat strip of spring material which is formed into virtually constant radius coils around itself 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 full rated load of the spring is reached after being deflected to a length equal to 1.25 times its diameter. Thereafter, it maintains a relatively constant force regardless of extension length. Load is basically determined by the thickness and width of the material and the diameter of the coil.

Fatigue life of Negator springs ranges from 2,500 cycles to over a million cycles depending upon the load and size of the spring

Working deflections of 50 times the drum diameter can be achieved. A wide variety of mounting configurations can be used such as cavity mounts, multiple spring mounts etc., depending on the application.

End connections can also be varied to fit the design situation. 

Special Features – Neg’ator Springs
- 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. 
- Variety of materials can be used. 

Hunter Spring’s experienced engineers can help you select a spring design to meet your space, life cycle, load and operation requirements.

Request more information to see how we can help you with a Neg’ator spring solution.