Patents by Inventor Steven A. Hallstrom

Steven A. Hallstrom 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: 6513648
    Abstract: The container of a mobile cargo trailer is provided with a reciprocating slat type conveyor floor in which the elongated slats are supported at their lateral edges on V-shaped bearings which are mounted on Y-shaped supports integral with sub-deck sections on the container bottom and joined together with watertight seals. Three cross beams are connected to different groups of the slats and are coupled to hydraulic cylinders located outwardly of the front end of the container and in horizontal alignment with the slats. The cylinders are coupled to a hydraulic fluid pressure source through an arrangement of control valves to effect movement of the group of slats simultaneously in a load moving direction and sequentially in the opposite, slat-retracting direction, with interengaging abutments on the cross drives arranged for moving one of the cross drives and its slats by hydraulic power applied only to the other two cross drive cylinders.
    Type: Grant
    Filed: November 6, 2000
    Date of Patent: February 4, 2003
    Inventors: Olof A. Hallstrom, Steven A. Hallstrom, Daniel C. Hallstrom
  • Patent number: 5490441
    Abstract: A fluid pressure piston-cylinder drive unit is reciprocated automatically by coupling the opposite ends of the cylinder through delivery conduits to a source of fluid pressure and exhaust through a switching valve in which a longitudinally reciprocative spool has a pair of passageways which reversibly couple one end of the cylinder to the source of fluid pressure and the other end of the cylinder to an exhaust conduit. The opposite ends of the switching valve contain shift pistons each of which engages an end of the spool through a coil spring. The shift pistons abut the opposite ends of an elongated rod which extends freely through a bore in the spool. Bypass conduits couple the opposite ends of the cylinder through the delivery conduits one to each end of the valve body such that fluid pressure in one delivery conduit from the source is coupled to one end of the valve body while exhaust fluid pressure from the other delivery conduit is coupled to the other end of the valve body.
    Type: Grant
    Filed: November 14, 1994
    Date of Patent: February 13, 1996
    Inventors: Olof A. Hallstrom, Steven A. Hallstrom, Daniel C. Hallstrom