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.

Abstract: The armature of an electromagnetic transducer, extending through the polarizing flux between opposing permanent magnet pole faces, is snubbed to limit its shock-induced excursions normal to the directions of its extent and of the flux field. Such snubbing helps to protect the armature from plastic damage and accompanying shift of magnetic balance of the transducer upon the occurrence of a strong mechanical shock in an arbitrary direction.

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.

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.

Abstract: The armature of an electromagnetic transducer, extending through the polarizing flux between opposing permanent magnet pole faces, is snubbed to limit its shock-induced excursions normal to the directions of its extent and of the flux field. Such snubbing helps to protect the armature from plastic damage and accompanying shift of magnetic balance of the transducer upon the occurrence of a strong mechanical shock in an arbitrary direction.

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.

Abstract: An electroacoustic assembly comprising a microphone having a diaphragm and supported on a face plate susceptible to vibratory effects. Vibration sensitivity is reduced by opposing the pressure effects on the diaphragm caused, on the one hand, by vibration of the assembly in the ambient air mass and by vibration of the air mass leading from the ambient air mass to the diaphragm, and on the other hand, by vibration of the effective mass of the diaphragm, generally augmented with additional mass, and including the effect of the internal air mass adjacent the diaphragm. Applications include hearing aids in which the microphone and its support are mechanically coupled to receiver components that may impart significant motion thereto.

Abstract: An electromechanical transducer having permanent magnet means forming a bias field in a region between poles, and a vibratable armature having a first part in that region. The armature has a second part extending from the first part substantially externally of that region. Magnetically permeable structure includes a portion opposing the second part across a transverse gap. The latter structure is included in a closed magnetic loop comprising said first and second parts, a working gap in said region and the transverse gap, and an electrical signal coil is threaded by the loop.

Abstract: An in-the-ear electroacoustic transducer is constructed to limit the effect of accretion of cerumen on acoustically active surfaces: to prevent cerumen from plugging passages for acoustical energy to the tympanic membrane and to facilitate the removal of cerumen from the transducer by the user. A casing has a hollow tubular wall, and diaphragm means is mounted to the casing near one end thereof, the casing being shaped for insertion in the ear to define a space generally bounded by the ear canal, the tympanic membrane and the diaphragm means. The diaphragm means has a flexible film surround, and stop means are provided to limit its movement inwardly of the casing. The transducer can be incorporated in or utilized as various hearing aids respectively adapted for different depths of insertion within the ear canal.

Abstract: An electromechanical magnetic transducer with a moving armature having (1) substantially pure translational adjustability, or (2) adjustability characterized by a substantially definite pre-chosen ratio of rotation to translation. The armature comprises an armature leg and an armature support yoke having plastically deformable yoke arms. A yoke arm comprises a pair of struts that are mutually inclined to provide a toggle-like action upon application of an adjusting force, such action opposing or enhancing the tendency of the support of the armature leg to rotate.

Abstract: Electrically conductive sheets comprising backplates for electret transducers are substantially encapsulated with hydrophobic electrically insulating coatings. The coatings are melt bonded to both faces of the sheets and to the edges of the sheet periphery. Likewise, the coatings are melt bonded to the interior edges of acoustic apertures in the sheets.

Abstract: A shielding enclosure for a magnetic flux producing device comprises inner and outer casings with closely fitting side walls. One or more leads extending from within the enclosure are laid down during assembly in a clearance slot or groove formed between the casing side walls, and thereafter threaded back out of the clearance slot or groove and extended through a closed aperture in the outer casing for terminal attachment.

Abstract: An electromechanical magnetic transducer with a moving armature that is adjustable relative to the working gap. The armature comprises an armature leg, crosspiece, and yoke arms, the adjustment being accomplished by inelastic distortion of the yoke arms. Substantially translational movement of the intrinsic position of the armature leg during adjustment is achieved by providing in each yoke arm one or more struts that undergo S-shaped distortion upon application of adjusting forces in appropriate directions. The structures are further adaptable for rotational adjustments of the armature leg in the gap.

Abstract: A transducer of the type converting between electrical and mechanical energy by means of the piezoelectric effect in a supported sheet of uniaxially oriented, electrically polarized thin high polymer film such as polyvinylidene fluoride, having surface electrodes thereon for connection to an electrical circuit. The transducer is characterized by an arrangement of the piezoelectric film into a series of elongate curved cylindrical segments of alternating sign of curvature, with the surface electrodes on the film being divided in selected locations between adjacent segments. A useful level of elastic stability is achieved without using a static pressure difference on the film, good electromechanical coupling is attained, and the individual transducer elements formed by the divided surface electrodes may be usefully interrelated electrically to substantially cancel even order harmonic distortion and enhance linearity of operation.