Gear continuously variable transmission or toothed CVT represents the planetary mechanism in which wheels form the closed kinematic chain in the form of closed contour. Gear CVT has constant engagement of wheels and secures the variable transfer ratio which depends on the torque. The transfer works automatically without any control system. Gear CVT has been created by inventors intuitively as essentially new mechanism having two degrees of freedom. Action of such mechanism could not be described theoretically on the basis of the existing theory of mechanisms with one degree of freedom. Numerous researches and numerical checks have allowed to formulate the main differences gear CVT from existing mechanisms and to describe theoretically its work.

The main difference of transfer is defined by presence of the closed contour. The new theoretical approach provides the analysis of equilibrium of separate links and the subsequent association of the received equations. Essentially new theoretical substantiation gear CVT has been executed on the basis of mechanics laws.

However long time the transmission was considered efficient only in the presence of an internal friction or additional resistance on one of wheels. Only recently it has been proved that the closed contour possesses unique property. Energy circulation in a contour creates the additional constraint which provides definability of the kinematic chain motion. There was a theoretical substantiation of gear continuously variable transfer as definable mechanical system with ideal constraints.

The developed theory is the tool of the analysis and synthesis of essentially new kind of transfers-the stepless gear transmissions adapting for variable technological loading.

The developed theory of force adaptation in the mechanics allows using the found effect of force adaptation for creation of basic new highly effective systems in various branches of techniques.

Let's list main routes of use of adaptive transmissions:
automatic mechanical gear box for easy and heavy transport techniques, adaptive drive of a drawing bench, adaptive drive of a lathe, adaptive motor-wheel, adaptive drive of transport cart, adaptive drive of manipulator, adaptive vibrating drive, adaptive tackle purchase, adaptive drive of sport techniques, automatic self-controlled electric drive, adaptive drive of electric motor car, adaptive drive of wind turbine, adaptive drive of piston of the hydro cylinder.