Abstract:
A balanced receiver providing significantly reduced vibration is disclosed. The balanced receiver comprises a closed loop operably attached between an armature and a diaphragm. The effective moving mass of the diaphragm is designed to match the effective moving mass of the armature. The closed loop facilitates the balancing of the motion of the diaphragm and the motion of the armature, thus reducing the vibration of the receiver.

Description:
RELATED APPLICATIONS 
   This application is a continuation-in-part of U.S. patent application entitled, “Vibration Balanced Receiver,” Ser. No. 09/479,134, filed Jan. 7, 2000 now abandoned. 

   TECHNICAL FIELD 
   The present invention relates to receivers and more particularly to a vibration balanced receiver for a hearing aid. 
   BACKGROUND OF THE INVENTION 
   Hearing aids have greatly contributed to the quality of life for those individuals with auditory problems. Technological advancements in this field continue to improve the reception, wearing comfort, life span and power efficiency of the hearing aid. In addition, several different hearing aid styles are available to choose from, i.e., behind the ear, in the ear, in the canal and completely in the canal. 
   The hearing aid is comprised of several components. One important component of the hearing aid is the receiver. The receiver is designed to utilize moving parts to generate acoustic energy in the ear canal of the individual using the hearing aid. Due to the motion of some of the parts within the receiver assembly, unintended vibrations may be transmitted through the receiver housing to the case of the hearing aid. In many situations, these vibrations are detrimental to the performance of the hearing aid. 
   The present invention is provided to solve these and other problems. 
   SUMMARY OF THE INVENTION 
   Generally stated, this invention sets forth a method and an apparatus for reducing vibration in hearing aid receiver assemblies associated with the movement of the armature-diaphragm assembly and the resulting reactionary forces. It is an object of this invention to provide a balanced receiver with significantly reduced vibration. 
   In accordance with the present invention, the receiver comprises a closed loop having an opposing first and a second expanded regions. An armature is operably attached to the first expanded region and a diaphragm is operably attached to the second expanded region. An effective moving mass of the armature is substantially equal to an effective moving mass of the diaphragm. 
   Another aspect of the present invention described above further includes the closed loop having an opposing first and a second regions. A first portion of the closed loop is adjacent the first expanded region and the first region, a second portion of the closed loop is adjacent the first region and the second expanded region, a third portion of the closed loop is adjacent the second expanded region and the second region and a fourth portion of the closed loop is adjacent the second region and the first expanded region, wherein all four portions of the closed loop are of equal length. 
   Yet a further aspect of the present inventions described above comprises a quadrilateral for the closed loop. The armature is operably attached near the first expanded region; and the diaphragm is operably attached near the second expanded region. 
   According to another aspect, the present invention comprises an elliptical-like shaped spring having a first and a second axis. A diaphragm is operably attached to the elliptical-like shaped spring near the intersection of a distal end of the second axis of the elliptical-like shaped spring. An armature is operably attached to the elliptical-like shaped spring near a proximate end of the second axis of the elliptical-like shaped spring. An effective moving mass of the armature is substantially equal to an effective moving mass of the diaphragm. 
   A further aspect of the invention involves a method of reducing the vibration of a receiver by providing an armature, a diaphragm and a closed loop having opposing first and second expanded regions. The armature is operably attached to the closed loop near a first expanded region and the diaphragm is operably attached to the closed loop near a second expanded region. The closed loop further having an opposing first and second regions, wherein the first and second regions are constrained from movement in a direction substantially parallel to an axis intersecting the opposing first and second expanded regions. 
   Yet another further aspect of the present invention involves a method of reducing the vibration of a receiver by providing an armature, a diaphragm and an elliptical-like shaped spring having a first and a second axis. The diaphragm is operably attached to the elliptical-like shaped spring near a distal end of the second axis of the elliptical-like shaped spring. The armature is operably attached to the elliptical-like shaped spring near the proximate end of the second axis of the elliptical-like shaped spring. The spring is constrained near a distal end of the first axis—a first region; and a proximate end of the first axis—a second region, wherein movement of the first and second regions in a direction parallel to the second axis is prevented. 
   Other advantages and aspects of the present invention will become apparent upon reading the following description of the drawings and detailed description of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the receiver; 
       FIG. 2  is a front view of the receiver of  FIG. 1 ; 
       FIG. 3  is an alternative embodiment of the closed loop of  FIG. 1 ; 
       FIG. 4  is a front view of an alternative embodiment of the present invention; 
       FIG. 5  is a front view of an alternative embodiment of the present invention; and, 
       FIG. 6  is a partial perspective view of a closed loop comprised of a strap. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated. 
   To improve the performance of a hearing aid, a receiver  10  can be designed to minimize or eliminate vibration within the receiver assembly. The receiver assembly  10  is illustrated in the  FIGS. 1 and 2 . The receiver  10  includes an armature  12  and a diaphragm  14 . The armature  12  and the diaphragm  14  are both operably attached to a closed loop  16 , preferably a pantograph. The closed loop  16 , i.e., quadrilateral, serves as a connection between the diaphragm  14  and the armature  12 . The quadrilateral structure  16  consists of an opposing first and second expanded regions  16   a ,  16   b  and an opposing first and second regions  16   c ,  16   d . In addition to the regions  16   a , (expanded)  16   b , (expanded)  16   c ,  16   d , there are four portions, or sides  16   e ,  16   f ,  16   g ,  16   h.  The first portion  16   e  is adjacent the first expanded region  16   a  and the first  16   c  region. The second portion  16   f  is adjacent the first region  16   c  and second expanded  16   b  region. The third portion  16   g  is adjacent the second expanded region  16   b  and the second region  16   d . The fourth portion  16   h  is adjacent the second region  16   d  and the first expanded  16   a  region. The armature  12  is operably attached to the quadrilateral structure  16  near the first expanded region  16   a . The diaphragm  14  is operably attached to the quadrilateral structure  16  near the opposing expanded region  16   b.    
   Alternatively, the structure of the closed loop  16  can be an elliptical-like shape and having an ellipticity of varying deviations. The elliptical-like shape comprising the structure of an elongated circle, oval, ellipse, hexagon, octagon or sphere. 
   The diaphragm  14  is preferably designed to have the same effective moving mass as the effective moving mass of the armature  12 . Opposing regions  16   c  and  16   d  of the quadrilateral structure  16  are constrained by a bracket  18 , thus preventing movement of the opposing regions  16   c  and  16   d  in a direction parallel to an axis (not shown) intersecting the opposing expanded regions  16   a ,  16   b . Movement by the armature  12  is accompanied by an opposing movement of the diaphragm  14 , thus the opposing motions of the armature  12  and diaphragm  14  work to effectively negate a relocation of the center of gravity within the receiver  10 . A movement inward, toward the center of the closed loop  16 , of the armature  12  causes an outward movement, away from the center of the closed loop, of the restrained regions  16   c ,  16   d  and thus, cause an inward movement of the diaphragm  14 . Preferably, the four portions  16   e ,  16   f ,  16   g,    16   h  are straight segments that allow for better transfer of motion through the quadrilateral structure  16 . 
     FIG. 6  depicts a partial view of the closed loop  16  as a strap having a thickness, T, ranging from 5×10 −4  to 3×10 −3  inch and a width, W, ranging from 10×10 −3  to 20×10 −3  inch. Preferably, the strap has a thickness of 5×10 −4  inch and a width between 10×10 −3  to 20×10 −3  inch. Alternatively, the closed loop  16  can be comprised of a wire, e.g., stainless steel, etc., having a diameter ranging from 2.0×10 −3  to 5.0×10 −3  inch. The strap experiences less maximum stress during operation of the pantograph  16  as compared to the wire. Thus, the receiver  10  can be operated at a higher output before material fatigue becomes a concern. 
   Increasing or decreasing the motion transfer by the quadrilateral structure assembly  16  can be accomplished by varying the length of the first  16   e  and fourth  16   h  portions in relation to the length of the second  16   f  and third  16   g  portions. See  FIG. 3 . For instance, increasing the length of the first  16   e  and fourth portion  16   h  to be equal to each other and greater then the length of the second  16   f  and third  16   g  portion, will, for the motion of region  16   a , increase the motion of the quadrilateral structure  16  assembly at region  16   b.    
   An alternative embodiment incorporates a spring  20  in place of the quadrilateral structure  16  as shown in  FIG. 4 . The spring  20  has a first axis  22  and a second axis  24  (shown in phantom). The diaphragm  14  is operably attached to the spring  20  near a distal end of the second axis  24  and an armature  12  is operably attached to the spring  20  near a proximate end of the second axis  24 . 
   It is further contemplated by this invention that an elliptical-like shaped spring  26  be used. The spring  26  can be an ellipse or a variation thereof. See  FIG. 5 . A first axis  22  divides the spring  26  into two members  28 ,  30 . The length of one member  28  is longer or shorter than the length of the other member  30 . This embodiment is similar to the previously mentioned embodiment of the quadrilateral structure  16  having first  16   e  and fourth  16   h  portions of substantially equal and longer (or shorter) length than the length of the second  16   f  and third  16   g  portions. Analogous to the embodiment of the quadrilateral structure  16 , the motion of the elliptical-like shaped spring  26  may be increased (or decreased) by differing the lengths of the members  28 ,  30 . 
   While specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention and the scope of protection is only limited by the scope of the accompanying claims.