Hydrodynamic drive and slipping clutch

Claim 1

A drive mechanism comprising: a torque converter including an input shell adapter to be driven by a prime mover, an impeller secured to said input shell and cooperating therewith to form an enclosed fluid space, a turbine disposed in the fluid space between said input shell and said impeller and cooperating with said impeller to form a toroidal fluid circuit, and an output hub connected to said turbine; a fluid operated friction clutch disposed between said turbine and said input shell, an engagement chamber formed between said clutch and said turbine, a disengagement chamber formed between said clutch and said input shell, and a plurality of compression spring means for providing a drive torque transmitting connection between said turbine and said output hub; variable opening passage means formed on said turbine and output hub for controlling fluid flow to said disengagement chamber in response to the torque transmitted through said spring means to effect an increasing engagement force on said clutch when the torque transmission through said spring means is above a predetermined value to limit the torque transmitted by said turbine and to limit the slip speed between said impeller and turbine, and output means drivingly connected to said clutch for delivering torque from said drive mechanism.