Patents by Inventor Helmut Tobel

Helmut Tobel 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).

  • Cylinder lock with warning of entry and drilling attempts
    Patent number: 4262506
    Abstract: A device for detecting entry or drilling attempts into cylinder locks. One or more housing bores not corresponding to core bores when the lock is in a neutral position having spring biased tripping pins connected to an alarm or indicator system and operable when an entry attempt is made not using a proper key or after having drilled-out the tumbler or tumbler and cylinder pins. The tripping pins detect the rotated cylinder having a space in the cylinder bore due an improperly made key or due to the cylinder bore having previously been emptied by the drilling operation.
    Type: Grant
    Filed: April 24, 1978
    Date of Patent: April 21, 1981
    Assignee: Zeiss Ikon Ag Goerzwerk
    Inventor: Helmut Tobel