Patents by Inventor Mark R. Schaefer

Mark R. Schaefer 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).

  • Dual voltage circuit tester
    Patent number: 6888341
    Abstract: A handheld dual voltage circuit tester, method and electronic circuit that quickly allows a technician to determine whether an automotive electrical system runs on a 12-14 volt circuit or 36-42 volt circuit. The tester may be used for automobiles having a single voltage electrical system, or automobiles with distinct electrical systems operating on one of a 12-14 volts circuit or a 36-42 volt circuit. The tester includes a screwdriver-type elongated handle and probe tip. The tester also includes electronic circuitry disposed within its handle, heat shrink tubing, a conductive spring assembly, a strain relief, a retractable coil cord, a ground clip and insulation that encloses the ground clip. The tester also includes electronic circuitry that emits light of a first color when a 12-14 volt circuit is sensed, and light of a second color when a 36-42 volt circuit is sensed.
    Type: Grant
    Filed: September 16, 2003
    Date of Patent: May 3, 2005
    Assignee: Snap-On Incorporated
    Inventors: Robert D. Johnson, Mark R. Schaefer, Daniel Mieczkowski
  • Quick system tester
    Patent number: D445703
    Type: Grant
    Filed: September 21, 2000
    Date of Patent: July 31, 2001
    Assignee: Snap-on Technologies, Inc.
    Inventors: Bruce W. Gaunt, Mark R. Schaefer
  • Cart-housing for automotive service equipment
    Patent number: D465895
    Type: Grant
    Filed: October 18, 2001
    Date of Patent: November 19, 2002
    Assignee: Snap-on Technologies, Inc.
    Inventors: Dean P. Pfefferle, Anwar Suharno, Craig F. Govekar, Michael M. Meeker, Larry G. Moller, Mark R. Schaefer