Patents by Inventor Jean Piret

Jean Piret has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4294137
    Abstract: A transmission with a variator, notably for automotive vehicles, is disclosed. The transmission is constituted by a variator which can be disconnected by engaging a constant-ratio direct drive. The engagement system is an either-or device.
    Type: Grant
    Filed: March 16, 1979
    Date of Patent: October 13, 1981
    Assignee: Regie Nationale Des Usines Renault
    Inventors: Jean Piret, Michel Jallas
  • Patent number: 4030381
    Abstract: Hydraulic control device for automatic change-speed transmissions, especially for motor vehicles, which comprises a fluid reservoir, a pump supplied from said reservoir, a main pressure regulation valve determining the line pressure of the device and supplied from said pump, a hydraulic circuit connected to said main pressure regulation valve and feeding a series of hydraulic receivers through an assembly of auxiliary regulation valves associated with time-lag means, respectively, one of said valves being supplied through a cut-off valve, said device further comprising at least one delivery conduit supplying fluid to a group of hydraulic elements mainly consisting of a flap valve and a gauged orifice connected in parallel.
    Type: Grant
    Filed: June 3, 1976
    Date of Patent: June 21, 1977
    Assignee: Regie Nationale des Usines Renault
    Inventors: Andre Lalin, Jean Piret