Patents by Inventor Colin John McKenzie Henry

Colin John McKenzie Henry 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).

  • Temperature control circuit for a hand held soldering tool
    Patent number: 3943326
    Abstract: In an electrical soldering iron having a soldering tip which is heatable to a predetermined operating temperature by means of an electrical heater element and in which electrical heating and control circuits are provided to supply electric current to the heater element in response to predetermined changes in temperature of the soldering tip an electrically conducting sensing element is operatively connected with the soldering tip having a resistance which varies directly with changes in its temperature. The heating circuit has a controlled rectifier as a switch and the control circuit is adapted to regulate said controlled rectifier to open and close the heating circuit in response to a predetermined change in the resistance of the sensing element. The control circuit includes a bridge circuit in which a bias compensating diode is connected to compensate for bias of the controlled rectifier.
    Type: Grant
    Filed: November 23, 1973
    Date of Patent: March 9, 1976
    Assignee: Royel International Pty. Ltd.
    Inventor: Colin John McKenzie Henry