Patents by Inventor Marc H. Doolittle

Marc H. Doolittle 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: 5737995
    Abstract: A power steering control valve (22) includes inner and outer valve members (40 and 42) which are rotatable relative to each other. A force transmitting assembly (114) is operable to transmit force which resists relative rotation between the valve members. A pressure chamber (138) is connected in fluid communication with a pump (24) and controls operation of the force transmitting assembly (114). The pump (24) supplies fluid at a relatively high flow rate during operation of the pump at a low speed and supplies fluid at a relatively low flow rate during operation of the pump at a relatively high speed. A secondary valve assembly (170) is connected in fluid communication with the pressure chamber (138) and defines an orifice (182 or 184) through which pressure is vented from the pressure chamber. The secondary valve assembly (170) is operated in response to relative rotation between the inner and outer valve members (40 and 42).
    Type: Grant
    Filed: February 28, 1996
    Date of Patent: April 14, 1998
    Assignee: TRW Inc.
    Inventor: Marc H. Doolittle