Abstract: The invention described in this specification relates to a hydrodynamic torque converter transmission of the type including two or more torque converter units connected in parallel between the input and output shafts and provided with means for interrupting the torque transfer through one or more of said units. One or more torque converters in the transmission is or are arranged with one bladed component thereof such as the pump or turbine blades selectively releasable from or engageable with an input shaft or an output shaft respectively whereby different driving conditions are obtained by engaging and disengaging the drive through different torque converters.

Abstract: A rotatable driving connection in which a plurality of abutments on one rotating part engage corresponding generally radial slots on the other rotating part with resilient material between each abutment and the contacting surfaces of its respective slot. The abutments are arranged in pairs of groups, the resultant of the forces of one group being perpendicular to the resultant of the other group. A leaf spring may be associated with each abutment to maintain contact between the resilient material and the walls of the slot and to prevent backlash. The area of contact between the resilient material and the walls of the slot varies in relation to the force transmitted by the connection.