Patents by Inventor Robert M. Berdahl

Robert M. Berdahl 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: 5044043
    Abstract: A drive control for a vehicle such as a floor scrubber, a floor sweeper, a pallet truck or the like, operated by a person walking or riding on a sulky behind it, includes first and second drive motors each arranged to drive a vehicle wheel. Manual means are provided whereby an operator by manipulation of a control may determine vehicle speed; forward and reverse direction; and turning right or left. A variable voltage is responsive to the operator's movements for providing an electrical signal representative of the desired speed in either the forward or reverse direction. Other movements by the operator of the control provide turning in the right or left direction. The means for detecting a turning control signal from the operator is effective to reduce the motor drive signal to the motor on the inside of the desired turn, from the level representative of the existing speed toward a no-speed level at a programmed rate.
    Type: Grant
    Filed: February 6, 1989
    Date of Patent: September 3, 1991
    Assignee: Tennant Company
    Inventors: Michael T. Basham, Robert M. Berdahl, Bruce E. Field
  • Patent number: 4825500
    Abstract: A drive control for a vehicle such as a floor scrubber, a floor sweeper, a pallet truck or the like, operated by a person walking or riding on a sulky behind it, includes first and second drive motors each arranged to drive a vehicle wheel. Manual means are provided whereby an operator by manipulation of a control may determine vehicle speed; forward and reverse direction; and turning right or left. A variable voltage is responsive to the operator's movements for providing an electrical signal representative of the desired speed in either the forward or reverse direction. Other movements by the operator of the control provide turning in the right or left direction. The means for detecting a turning control signal from the operator is effective to reduce the motor drive signal to the motor on the inside of the desired turn, from the level representative of the existing speed toward a no-speed level at a programmed rate.
    Type: Grant
    Filed: August 17, 1987
    Date of Patent: May 2, 1989
    Assignee: Tennant Company
    Inventors: Michael T. Basham, Robert M. Berdahl, Bruce F. Field
  • Patent number: 4709771
    Abstract: A drive control for a vehicle such as a floor scrubber, a floor sweeper, a pallet truck or the like, operated by a person walking or riding on a sulky behind it, includes first and second drive motors each arranged to drive a vehicle wheel. Manual means are provided whereby an operator by manipulation of a control may determine vehicle speed; forward and reverse direction; and turning right or left. A variable voltage is responsive to the operator's movements for providing an electrical signal representative of the desired speed in either the forward or reverse direction. Other movements by the operator of the control provide turning in the right or left direction. The means for detecting a turning control signal from the operator is effective to reduce the motor drive signal to the motor on the inside of the desired turn, from the level representative of the existing speed toward a no-speed level at a programmed rate.
    Type: Grant
    Filed: April 21, 1986
    Date of Patent: December 1, 1987
    Assignee: Tennant Company
    Inventors: Michael T. Basham, Robert M. Berdahl, Bruce E. Field