Patents by Inventor Keith D. Rapp

Keith D. Rapp 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).

  • Calculator driving and battery pack recharging circuit
    Patent number: 4140957
    Abstract: A circuit to conveniently and safely drive an electronic calculator from a source of ac power or, alternately, from either one of a plurality of disposable batteries or a unique, rechargeable battery pack. The present circuit includes an arrangement of contact means particularly positioned in a predetermined relationship within the battery compartment of the calculator and on the rechargeable battery pack. When disposable batteries are deposited inside the battery compartment of the calculator and an ac adapter accessory is connected to provide power to the calculator, the disposable batteries are electrically isolated from the ac source. However, when the rechargeable battery pack is deposited inside the battery compartment of the calculator and the ac adapter is connected to provide power to the calculator, the battery pack is recharged.
    Type: Grant
    Filed: June 20, 1977
    Date of Patent: February 20, 1979
    Assignee: Rockwell International Corporation
    Inventor: Keith D. Rapp