US 6,763,571 B2Granted

Armature assembly for balanced moving armature magnetic transducer and method of locating and adjusting same

AssigneeTibbetts Industries, Inc.

InventorsGeorge C. Tibbetts, Joseph A. Sawyer

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Abstract

In a folded armature assembly the vibratory end portion of the armature is prelocatable both translationally and rotationally relative to the facing pole surfaces of the permanent magnetic flux means before attachment of the supported portion of the armature to said means. The armature has wings extending laterally from the supported portion to form therewith a connecting bridge portion, and the wings are formed to provide pads extending normal to the bridge. A magnet strap with attached magnets fits slidably between the pads, with a clearance from the bridge of the armature, to permit said locations before the parts are permanently attached. After attachment and with the magnets magnetized, the armature may be adjusted substantially in translation to magnetic center between the pole faces by appropriate plastic deformation of the bridge. In a preferred embodiment, an improved structure is provided for viscoelastic damping of the undesirable second natural resonant mode of the folded armature.

Claims4

Dependent claims

A method of assembling, locating and adjusting a folded armature with the permanent magnetic circuit elements of an electromagnetic transducer, comprising the steps of

forming and folding a flat sheet of armature material to form elongate, generally planar and spaced parallel supported and vibratory arms each joined at one end to the other by an integral connecting portion, and a pair of integral wings extending laterally from said supported arm and forming a bridge therewith, and folding the wings to form mutually parallel pads normal thereto,
attaching a pair of flat magnets in spaced parallel relation to the inner surfaces of a closed loop magnet strap,
slidably fitting the magnet strap between said pads with a clearance from said bridge and with said vibratory arm extending between said magnets,
slidably adjusting the position of the magnet strap on the pads to vary the position of said vibrating arm rotationally with respect to its parallelism to the magnets and translationally with respect its spacing therefrom, and
permanently attaching the magnet strap to said pads.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/346,590Filed 17 Jan 2003 · division
Priority: 8 Feb 2001
Published: US 2003/0138114 A124 Jul 2003
Granted: 20 Jul 2004
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

H04R 11/00
Transducers of moving-armature or moving-core type
H01H 49/00
Apparatus or processes specially adapted to the manufacture of relays or parts
H01H 50/30
Movable parts of magnetic circuits, e.g. armature: mechanical arrangements for preventing or damping vibration or shock, e.g. by balancing of armature
H01H 51/2245
Comprising pivotable armature, pivoting at extremity or bending point of armature: armature inside coil

Family

Application09/779,920Parent of this division · filed 8 Feb 2001
US 2003/0138114 A1Pre-grant publication · published 24 Jul 2003
US 6,526,153 B2Parent of this division
US 2002/0125972 A1Published application
US 6,763,571 B2This patent

From the US filing history. Foreign family members aren’t listed.