Ferrier double bow separator works on which principle?

The Ferrier separator is a convenient instrument for accomplishing separation. It is applied and stabilized with compound. The jackscrews of the separator are activated with the separator wrench to draw the teeth slightly apart, creating a maximum space of 0.25 to 0.5 mm. It is desirable to provide only this minimum separation and to remove the separator as soon as possible. Sturdevants operative dentistry 7th edition page e85 - e86