Patents Examined by M. Nelson Geary, III
  • Magnetically shielded electromagnetic acoustic transducer
    Patent number: 4956868
    Abstract: An electromagnetic transducer including a diaphragm mechanically connected to an armature, a coil wound tranversely around the armature, a permanent magnet adjacent the armature, and one or more additional magnetic members completing a magnetic circuit having a plane of symmetry longitudinally bisecting the armature, has a magnetic shield formed by two high-permeability casing halves joined together along a joint plane substantially concident with the plane of symmetry.
    Type: Grant
    Filed: October 26, 1989
    Date of Patent: September 11, 1990
    Assignee: Industrial Research Products, Inc.
    Inventor: Elmer V. Carlson