Patents by Inventor David C. Mitchell

David C. Mitchell 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: 4254966
    Abstract: In this arrangement, the pitching, rolling and steering movements that take place between a motor car and a trailer are separately accommodated, with the pitching movements being accommodated by a horizontal transverse hinge structure arranged to be nearest the towing vehicle and comprising two relatively moving parts, motion therebetween occurring through an elastic member. A device is provided for stressing the elastic member in a variable and controlled manner whereby weight may be taken off the rear axle of the car to a desired extent and distributed to the front axle of the car and to the trailer axle. The rolling movements are accommodated by a stub-shaft at the front of the trailer, rotatably inserted into a longitudinally extending horizontal hole provided in the second of the above moving parts, and the steering movements are accommodated by an eye at the rear end of the stub-shaft, pivotally engaged in a fork-like member, carried by the trailer towbar, for motion about a vertical axis.
    Type: Grant
    Filed: July 5, 1979
    Date of Patent: March 10, 1981
    Inventor: David C. Mitchell
  • Patent number: 4142815
    Abstract: A concrete slab striker employs a counter-rotating roller to grade or strike off the surface of a freshly poured concrete slab while the concrete is still in the plastic state. An elongated roller is supported on a form bordering the concrete slab in engagement with the concrete surface. A manually movable support frame and pull device coupled to opposite ends of the roller allow workmen to pull the roller across the concrete slab. Simultaneously, the roller is rotated in a direction opposite to its direction of travel relative to the surface of the concrete slab. A thin coating of hardened concrete particles accumulates on the roller to impart a texturized surface to the concrete slab when cured.
    Type: Grant
    Filed: November 28, 1977
    Date of Patent: March 6, 1979
    Inventor: David C. Mitchell