Fluid flow transmission, especially for rail vehicles

Claim 1

IN A FLUID FLOW TRANSMISSION COMPRISING A HOUSING HAVING MOUNTED THEREIN AT LEAST TWO COAXIALLY ARRANGED FLUID FLOW MACHINES EACH COMPRISING A ROTATABLE PRIMARY WHEEL AND A ROTATABLE SECONDARY WHEEL, SAID FLUID FLOW MACHINES BEING OPERABLE IN THE SAME DIRECTION OF ROTATION AND BEING RESPECTIVELY DESIGNED FOR DIFFERENT VELOCITY RANGES AND BEING ADAPTED TO BE MADE EFFECTIVE AND INEFFECTIVE: A HOLLOW PRIMARY SHAFT HAVING SAID PRIMARY WHEELS CONNECTED THERETO FOR ROTATION THEREWITH, GEAR MEANS ADAPTED TO BE DRIVINGLY CONNECTED TO A PRIMARY MOVER AND INCLUDING A GEAR INTERPOSED BETWEEN TWO FLUID FLOW MACHINES AND DRIVINGLY CONNECTED TO SAID PRIMARY SHAFT, AND A SECONDARY SHAFT COMMON TO SAID SECONDARY WHEELS AND CONNECTED THERETO FOR ROTATION THEREWITH, SAID SECONDARY SHAFT EXTENDING THROUGH SAID PRIMARY SHAFT AND FROM ONE SIDE WALL OF THE HOUSING TO THE OPPOSITE SIDE WALL TO PERMIT POWER TAKE OFF AT BOTH ENDS OF THE SECONDARY SHAFT THROUGH THE RESPECTIVE SIDE WALLS OF THE HOUSING.