Richard E Hunt

US Patent:

44436670, Apr 17, 1984

Filed:

Jan 11, 1982

Appl. No.:

6/338231

Inventors:

Richard M. Hunt - Indianapolis IN

Assignee:

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

International Classification:

H04R 1100

US Classification:

179115R

Abstract:

An electromagnetic transducer is disclosed that includes a pole assembly (110) comprising a central pole piece (112) upstanding from a back plate (114). A coil assembly (120) is disposed about the central pole piece (112) and rests on the back plate (114). In addition, an inverted cup-shaped permanent magnet (130) having a central opening (132) in its base (131) is positioned so that the wall (134) of the magnet circumscribes the coil assembly (120) and rests on the back plate (114). The rim of the central opening (132) in the base (131) of the permanent magnet (130) is spaced from and encircles the upper end of the central pole piece (112). Also the wall (134) of the permanent magnet (130) is of a height that the upper surface of the base (131) lies in essentially the same plane as the upper surface of the pole piece (112). A central armature (222) is supported by a nonmagnetic diaphragm (221) so as to be positioned above and spaced from the central pole piece (112). The armature (222) lies in a plane that is essentially parallel to the plane of the upper surface of the pole piece (112), and the armature is of a size that it overlaps the portion of the base (131) of the permanent magnet (130) immediately adjacent to the central opening (132).

US Patent:

44254822, Jan 10, 1984

Filed:

Mar 8, 1982

Appl. No.:

6/355937

Inventors:

Chester M. Bordelon - Shreveport LA
Richard M. Hunt - Indianapolis IN
Robert A. Wheeler - Shreveport LA

Assignee:

Western Electric Company - New York NY

International Classification:

H04R 900

US Classification:

179120

Abstract:

The disclosure relates to a ring armature electroacoustic transducer adapted for use as the receiver for telephone sets and for other purposes. The exemplary embodiment comprises the following elements coaxial about a common vertical axis: (a) a cylindrical ring permanent magnet (15) of Fe-Cr-Co material, (b) an annular disc upper pole piece (20) seated on magnet 15 and having at its inner margin a downwardly salient annular boss (30) providing an upper pole tip, (c) a lower pole piece (35) providing an annular lower pole tip (37) and aflange (36) coupling such tip (37) to the bottom of the magnet, (d) an armature support (40) within the magnet (15), (e) an annular disc armature (50) seated on the support (40), (f) a diaphragm (60) on the armature (50), and (g) a terminal plate (45) supporting such elements. The armature (50) is seated on a circular edge (90) on the support (40). The support (40), lower pole piece (35) and plate (45) form a unitary structure.