Abstract:
The compliance of a receiver tube for a hearing instrument may be enhanced by fabricating it as a composite assembly of a tube and a compliant insulator positioned between the tube and the receiver. The material of the insulator is selected such that it has a greater compliance than that of the tube.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is related to and claims the benefit of commonly-owned U.S. Provisional Application for Patent, Ser. No. 60/987,798, filed Nov. 14, 2007, and is also related to commonly-owned U.S. patent applications Ser. No. 10/610,449, filed Jun. 30, 2003, and titled “Feedback Reducing Receiver Mount and Assembly,” and No. 10/945,704, filed Se. 21, 2004, and titled “Feedback Reducing Receiver Mount and Assembly,” all incorporated herein by reference. 
     
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
       [0002]    A receiver tube for a hearing instrument receiver, the component that generates the sound heard by the user of the hearing instrument, connects the output of the receiver with the outside of the shell, conveying the sound from the receiver to the user&#39;s inner ear. To accommodate a wax guard and provide a secure attachment for the receiver, the receiver tube may be configured as a composite of a tube, a cup, an insulator, and a flange that mates with the receiver. An insulator fashioned from a compliant material minimizes vibration that may be induced into the shell by the action of the receiver. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]      FIG. 1  is a cross-sectional view of a composite receiver tube; 
           [0004]      FIGS. 2 and 3  are drawings of an insulator for a composite receiver tube; 
           [0005]      FIGS. 4 and 5  are drawings of a flange for a composite receiver tube; and 
           [0006]      FIG. 6  illustrates a composite receiver tube within a shell residing in the ear canal of the user. 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0007]    A composite receiver tube  10  for a hearing instrument receiver  20 , is shown in  FIG. 1 , with the receiver  20  drawn partially in phantom. The composite receiver tube  10  in  FIG. 1  comprises four elements: a tube  30 , a cup  40 , an insulator  50 , and a flange  70  that mates with the receiver  20 . The cup  40  and the flange  70  help facilitate the manufacturing and assembly of the composite receiver tube, but may be omitted. 
         [0008]    The tube  30 , the cup  40 , and the insulator  50  may have a circular cross section or a cross section of some other shape as desired. The flange  70  provides a physical or mounting interface between the insulator  50  and the receiver  20 . As shown in  FIGS. 1 and 4 , the flange  70  may have an optional curved section  72  conforming to the receiver  20 . The flange  70  may be secured to the receiver  20  with an adhesive or by spot-welding, or a combination of the two. 
         [0009]    The tube  30  may be fabricated from a synthetic material such as an elastomer or any other suitable material. One such elastomer is marketed by DuPont Dow Elastomers, L.L.C. under the trademark Viton. A Viton elastomer having a hardness rating of 50 on the Shore A scale will be suitable. 
         [0010]    The tube  30  resides in the cup  40 , which in turn resides in a recess  52  in the insulator  50 . The cup  40  may be fabricated from a metal such as steel or any other suitable material. As depicted here, the cup  40  and the conforming recess  52  are cylindrical, but they could easily assume a different shape. The tube  30  may be secured to the cup  40  with an adhesive. 
         [0011]    In addition to the recess  52  for the cup  40 , the insulator  50  has a sound channel  54  ( FIG. 2 ). As illustrated in  FIGS. 2 and 3 , the insulator  50  has a flared section  56  that widens out towards the flange  70 . The flared section  56  reduces the rigidity of the insulator  50  and increases the compliance of the insulator  50 . The flared section  56  may assume a variety of shapes, including conical, hyperboloidal (technically, one half of a hyperboloid), and paraboloidal. 
         [0012]    A facing  58  on the flared section  56  ( FIGS. 2 and 3 ) provides a surface which mates with the flange  70 . The facing  58  may have a curved surface  60  that conforms to the curved section  72  of the flange  70  ( FIG. 4 ), terminating in a lip  62 . An opening  74  in the flange  70  ( FIGS. 4 and 5 ) connects the sound channel  54  of the insulator  50  with the opening (not shown) of the receiver  20 . 
         [0013]    The insulator  50  may be fabricated in an injection-molding process, incorporating the cup  40  and the flange  70  during the process as appropriate. The insulator  50  may be made from a soft, rubber-like material such as a fluorosilicone having a hardness rating of 20-30 on the Shore A scale. Compared to the tube  30 , the insulator  50  exhibits greater compliance. As noted above, the compliant effect of the insulator  50  is further enhanced by the flared section  56 . 
         [0014]    If desired, the inner-ear side  64  of the insulator  50  could be connected directly to tube  30  while the receiver side  66  of the insulator  50  could be affixed directly to the receiver  20 , foregoing the cup  40  and the flange  70 , respectively. Where the cup  40  is omitted, the recess  52  on the inner-ear side  64  of the insulator  50  may be sized to the outer dimensions of the tube  30 . 
         [0015]    The composite receiver tube  10  and the receiver  20  are shown within a shell  80  (shown in phantom), residing in the user&#39;s ear canal  90  in  FIG. 6 . The tube  30  passes through the wall  82  of the shell  80 . Optional mounting brackets  100 , anchored within the shell  80  and attached to the insulator  50 , and supporting the composite receiver tube  10  within the shell  80 , are illustrated schematically. After the composite receiver tube  10  has been installed in the shell  80 , the end  32  of the tube  30  protruding from the shell  80  is typically trimmed flush with the outer surface  84  of the shell  80 .