Patent ID: 8627657

Claim:
Hydrostatic transmission apparatus for a vehicle having at least two drive members disposed one after the other in the direction of travel of said vehicle, the apparatus comprising a main hydraulic pump having two orifices, two main ducts that are respectively a feed main duct and a discharge main duct, first and second hydraulic motors connected to the main pump for the purpose of driving respective ones of said first and second drive members, and a link selector, at least the first hydraulic motor being a dual motor made up of two elementary motors, a series link existing between the first elementary motor of said first hydraulic motor and the second hydraulic motor, the link selector being suitable for taking up a first position in which a series loop including said series link coexists with a direct loop including a direct link linking at least the second elementary motor of the first hydraulic motor to the two respective orifices of the main pump, and a second position in which at least one of said direct and series loops is bypassed by a bypass link, the apparatus further comprising a constriction valve suitable for being activated to restrict the flow of fluid through said bypass link, and a controller for controlling the constriction valve, as a function of the stroke of a control member.