Patents by Inventor DuWayne E. Kramer

DuWayne E. Kramer 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).

  • Publication number: 20070290492
    Abstract: A personal ability vehicle (PMV) includes a frame with front and rear subframes. A steering mechanism is mounted on the front subframe and includes a steering front wheel connected to a tiller. The rear subframe includes a suspension mount comprising a pair of rear support legs. An anti-tip suspension includes a pair of trailing arms each mounting a trailing wheel. Each trailing arm is pivotally mounted on a respective support leg whereby the suspension is inevitable through a limited range of motion about a transverse suspension pivotal axis. A pair of spring assemblies are attached to the trailing arms and are adapted for selectively engaging the support legs to provide a counter-rotational torque force around the suspension pivotal axis in order to resist backwards tipping of the PMV, for example, when it is ascending an inclined sloping surface. Relatively uniform proportional, weight distribution on said steering front, main and trailing wheels is maintained throughout a range of loads.
    Type: Application
    Filed: June 19, 2006
    Publication date: December 20, 2007
    Inventors: DuWayne E. Kramer, Brian W. Mellies
  • Patent number: 4834409
    Abstract: A personal mobility vehicle includes a main frame unit with front and back ends, both with wheels thereon, a steerable front wheel, an operator's seat and vehicle controls. A pair of spaced rear wheels are mounted at the back end of the vehicle and include moveably mounted axles supporting the rear wheels and connected to arms with mechanisms for selectively angularly moving the axles outwardly and inwardly of the main frame unit to vary wheel base and wheel track. A motor is connected to the wheel support structure for remotely varying the wheel base and wheel track. A separate drive motor is operatively connected to the wheels for movement of the vehicle.
    Type: Grant
    Filed: October 13, 1987
    Date of Patent: May 30, 1989
    Inventor: DuWayne E. Kramer
  • Patent number: 4570739
    Abstract: A personal mobility vehicle includes a floor pan with a rear drive unit at one end and a steerable front wheel at the other end. The drive unit is separable from the floor pan and includes spaced apart, differentially connected rear wheels, an electric motor, and belts and pulleys drivingly connecting the motor to a differential unit. The front wheel is steered by a tiller. A seat with a folding back is removably connected to the floor pan toward the pan rear end to concentrate the weight of the driver over the rear wheels to aid in traction. A brake is provided on the front wheel and is lockable for parking purposes. Each of the drive unit, seat unit, a battery, and a floor pan unit weighs less than thirty pounds such that the separated components can be easily lifted and manipulated for transportation of the vehicle between sites of use.
    Type: Grant
    Filed: September 29, 1983
    Date of Patent: February 18, 1986
    Assignee: Burke, Inc.
    Inventor: DuWayne E. Kramer