Patents by Inventor Calvin D. Stringer

Calvin D. Stringer 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).

  • Steerable, self-powered shopping cart towing apparatus and method for making same
    Patent number: 5573078
    Abstract: A steerable, self-powered device for use in towing and guiding a plurality of shopping carts attached together in a line from one location to another is disclosed which has a pair of electrically driven wheels located in the rear thereof, and a single wheel located in the front thereof for use in steering the towing and guiding device. The towing and guiding device is small and low to the ground, and includes a retaining mechanism which may be attached to the line of shopping carts by connection to the bottom front cross-bar of the front-most shopping cart in the line of shopping carts. The towing and guiding device is powered by one or more batteries, and in the preferred embodiment includes a battery charger and a retractable cord to supply power to the battery charger.
    Type: Grant
    Filed: June 23, 1995
    Date of Patent: November 12, 1996
    Inventors: Calvin R. Stringer, Calvin D. Stringer