A Constant force spring or Clock Spring is a roll of prestressed  strip which exerts a nearly constant restraining force to resist uncoiling. The force is constant because the change in radious of curvature is constant. This is true if the change in coil diameter, due to buildup is disregarded long extension capabillities,constant torque and virtual absence of inter coil friction have led many designers to specify constant force springs in such application as brush spring for motors, counter balance spring for window sashes and carriage return spring for typewriters. Constant force motor spring are used to drive mechanisms for timers, movie cameras and cable retractors Feature:- Accuracy Durable, Constant resistance, Hardend & Temper, High tensile Condition:- New Quality:- Good Usuage:- Industrial Advantages:- Easy to use Durability:- Long life Performance:- Optimum OD: 42 mm Width: 9.5 mm Thickness: 1.5 mm

A Constant force spring or Clock Spring is a roll of prestressed  strip which exerts a nearly constant restraining force to resist uncoiling. The force is constant because the change in radious of curvature is constant. This is true if the change in coil diameter, due to buildup is disregarded long extension capabillities,constant torque and virtual absence of inter coil friction have led many designers to specify constant force springs in such application as brush spring for motors, counter balance spring for window sashes and carriage return spring for typewriters. Constant force motor spring are used to drive mechanisms for timers, movie cameras and cable retractors Feature:- Accuracy Durable, Constant resistance, Hardend & Temper, High tensile Condition:- New Quality:- Good Usuage:- Industrial Advantages:- Easy to use Durability:- Long life Performance:- Optimum OD: 42 mm Width: 9.5 mm Thickness: 1.5 mm