Abstract:
An ear piece assembly ( 10, 100, 200, 300, 500, 600, 700, 800, 900, 1000 ) designed for a stethoscope or other headpiece, and configured to allow rotation of an ear tip ( 20, 120, 220, 320, 420, 520, 620 ) of the assembly about a central axis (relative to the rest of the assembly) and to allow limited off axis movement of the ear tip (relative to the rest of the assembly). In typical embodiments, the ear piece assembly is designed to fit a user&#39;s ear canal and stay in place during typical use without rotational or off axis movement of the ear tip relative to the ear canal, and to provide substantially more comfort to the user than would a headpiece with a conventional ear tip assembly, particularly for prolonged wearing by the user. Other aspects of the invention are a headpiece (e.g., a stethoscope headpiece) or stethoscope including an embodiment of the earpiece assembly, an ear piece housing body configured for use in an embodiment of the earpiece assembly, and an ear tip configured for use in an embodiment of the earpiece assembly.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an earpiece assembly of a headpiece, and to stethoscopes and other headpieces that include such an earpiece assembly. In a class of embodiments, the inventive earpiece assembly includes an ear tip portion (which directly interfaces with the user&#39;s ear canal) configured to be rotatable on axis (about the earpiece assembly&#39;s longitudinal axis) relative to the rest of the earpiece assembly and to have limited freedom to pivot off axis (about at least one axis that is perpendicular to the longitudinal axis) relative to the rest of the earpiece assembly. 
         [0003]    2. Background of the Invention 
         [0004]    Throughout this disclosure, including in the claims, the expressions “headset,” “headpiece,” and “head piece” are used as synonyms to denote an apparatus configured to be worn on or positioned against a user&#39;s head. Examples of headsets are the head pieces of stethoscopes (both acoustic (or passive) and active (e.g., electronic) stethoscopes), audio headphones (of the type that include a small loudspeaker for each ear, to make audible the output of a home or portable audio system), and telephone headsets (of the type including a microphone as well as a small loudspeaker for each ear or a single one placed in the lumen structure etc. as mentioned previously). 
         [0005]    Throughout this disclosure, including in the claims, the expression “ear piece assembly” (or “earpiece assembly” or “earpiece”) denotes a subassembly (or portion) of a head piece, intended and configured to be positioned in, or otherwise in direct contact with, an ear of the head piece&#39;s user. The expression “ear tip” (or “ear tip” portion) herein denotes an element or portion of an ear piece assembly that is intended and configured to be positioned in, or otherwise in direct contact with, an ear of the ear piece assembly&#39;s user, and assumes that the ear piece assembly includes at least one other element (or portion) that is not an ear tip. Examples of ear tips include the small loudspeakers (sometimes referred to as sound transducers) of a pair of audio headphones, and the soft ear tips (which generally do not contain transducers) of the head pieces of passive stethoscopes. 
         [0006]    Throughout this disclosure, including in the claims, the term “proximal” (with reference to a headpiece) denotes “toward” the center of the head of a user who wears the headpiece, and the term “distal” (with reference to a headpiece) denotes “away from” the center of the head of a user who wears the headpiece. Thus, a “proximal” portion (e.g., “proximal” end) of an earpiece assembly (or a subassembly of an earpiece assembly) denotes a portion of the assembly (or subassembly) located “toward” or relatively near to the center of the head of a user who wears a head piece including the assembly, and a “distal” portion (e.g., “distal” end) of an earpiece assembly (or a subassembly of an earpiece assembly) denotes a portion of the assembly (or subassembly) located “away from” or relatively far from to the center of the head of a user who wears a head piece including the assembly. An ear tip portion of an earpiece assembly is located at the proximal end of the assembly during use. 
         [0007]    Throughout this disclosure including in the claims, the expression “active” stethoscope (or “active” sound detection device) denotes a stethoscope (or sound detection device) that includes an acoustic transducer useful for converting acoustic waves (e.g., body sounds of interest) into another form of energy. 
         [0008]    Herein, the expression “electronic” stethoscope (or “electronic” sound detection device) denotes a stethoscope (or sound detection device) that includes an acoustic transducer useful for converting acoustic waves of interest (e.g., body sounds) into at least one electric signal. Also herein, the expression “passive” stethoscope (or “passive” sound detection device) denotes a stethoscope (or sound detection device) that does not include an acoustic transducer. 
         [0009]    Throughout this disclosure, including in the claims, each of the expressions “acoustic transducer” and “sound transducer” denotes a device for converting acoustic waves into another form of energy. For example, one type of acoustic transducer is a typical microphone configured to convert acoustic waves into an electrical signal. Another example of an acoustic transducer is a device configured to convert acoustic waves into electromagnetic waves (e.g., visible radiation or electromagnetic radiation whose wavelength or wavelengths is or are outside the visible range), and optionally also to convert the electromagnetic waves into an electrical signal. Acoustic transducers are sometimes referred to as sound pick-ups, and are sometime referred to herein simply as transducers. 
         [0010]    Throughout this disclosure including in the claims, the expression “axis” of an earpiece assembly (or ear tip), unless otherwise defined, generally assumes that the earpiece assembly (or ear tip) has a longitudinal axis and denotes the longitudinal axis of the earpiece assembly (or ear tip). For example, the axis of an earpiece assembly having generally cylindrical form is the assembly&#39;s central longitudinal axis. 
         [0011]    Throughout this disclosure including in the claims, the expression “bearing” is used in a broad sense to denote a first element (e.g., unit  28  of  FIG. 9 , unit  128  of  FIG. 13 , or element  529  of  FIG. 21 ) configured to support a second element (e.g., an ear tip) fitted onto the first element, such that the second element has freedom to rotate (“on axis,” where “axis” here denotes the first element&#39;s longitudinal axis) relative to the first element. Optionally also, the second element has freedom to pivot (“off axis”) relative to the first element. For example, one type of bearing is a ball joint unit (e.g., unit  28  of  FIG. 9  or  10 , or unit  128  of  FIG. 13 ) having a ball portion, and configured to support an ear tip fitted onto the ball portion, such that the ear tip has freedom to rotate (“on axis”) and freedom to pivot (“off axis”) relative to the ball portion. Another exemplary type of bearing is an element (e.g., element  529  of  FIG. 21 ) having a rotationally symmetric support portion (e.g., the partial conical end portion of element  529 ), said element being configured to support an ear tip that has been fitted onto it, such that the ear tip has freedom to rotate (“on axis”) relative to the support portion. 
         [0012]    Throughout this disclosure including in the claims, the herein used expressions “sound tube” or “tube”, unless otherwise defined, generally refers a formed tube or tubes that are an integral part of the head piece portion of a complete stethoscope or other head piece assembly. 
         [0013]    Stethoscopes are used by health care givers (primarily physicians, so that health care givers will be referred as such herein) to aid in the detection of body sounds for the purpose of diagnosing various symptoms such as heart beat anomalies or lung infections, etc. This procedure is commonly called auscultation. 
         [0014]    In a class of embodiments, the invention pertains to a stethoscope earpiece designed to be inserted into a user&#39;s outer ear canal for purposes of efficiently transmitting sound from a remote stethoscope chest piece placed on a patient&#39;s body to the user&#39;s ear. The sound transmission is usually accomplished by one of two methods. The first and most common method is to utilize tube structures called lumens to connect the chest piece to the two ear pieces. Stethoscopes implementing this method are commonly called “acoustic” stethoscopes. The second method is to use an electronic chest piece with various sound sensing devices such as microphones. The sound sensing devices in the chest piece work with an electronic amplifier which then drives miniature loudspeakers that are generally placed in the earpiece assembly. Wires are used in the lumen to connect the speakers to the amplifier in the chest piece. A miniature loudspeaker may also be placed in the lumen structure or chest piece itself. This is well known in the art. Stethoscopes implementing this method are commonly called “electronic” or “active” stethoscopes. 
         [0015]    Myriad devices are known in the art which attempt to improve the comfort and seal efficiency of stethoscope headpiece ear tips. Much of the art attempts to address the issues of ear tip softness, comfort of fit, ease of cleaning, etc. 
         [0016]    The outer ear is the most external portion of the ear. The outer ear includes the pinna (the flesh covered cartilage), the ear canal, and the most superficial layer of the ear drum (also called the tympanic membrane). Portions of the ear after the ear drum such as the middle ear etc. are blocked from access to the outside world. The axis of the ear canal does not converge to the lower center of the head on the same plane as the ear canal, but rather converges slightly upwards and forward towards the upper bridge of the nose. This forward bend is roughly 10 to 15 degrees from the head&#39;s sideways horizontal axis (the Y axis in  FIG. 3 ). 
         [0017]    This is the reason why all good quality stethoscopes have the ear tips bent at approximately 10 degrees off the center line of the head piece. When placing the stethoscope headpiece on his ears, the physician instinctively knows to point the ear piece portions forward toward his face, i.e. the 10 degree angle is toward the back of his head. This orientation is clearly shown in  FIG. 3 . 
         [0018]    The stethoscope ear tip generally fits into the distal portion of the ear canal, some 20 to 26 mm in length, whose proximal portion faces the ear drum. Depending on ear canal entry variations, the ear tip may penetrate 7 to 10 mm while deforming itself and the canal entry. Thus a seal is formed. 
         [0019]    Once so positioned (with a seal), the ear tip is not in the position to rotate freely because of deformation and being out-of-center with reference to the imaginary ear canal rotation axes and the axis of the stethoscope headpiece arms. This will be explained in more detail in the body of this teaching. 
         [0020]    Several devices which include rotatably mounted ear tips are described in the following references: 
         [0021]    U.S. Pat. No. 6,514,213, to Moteki et al., describes a ball bearing in an earpiece assembly for ease of rotation. However it does not address the off axis angular changes due to the ear canal being set at an angle; 
         [0022]    U.S. Pat. No. 5,002,151, to Oliveira et al., describes a ball and socket assembly, but in a fixed application designed for stationary hearing aids; 
         [0023]    U.S. Pat. No. 3,710,888, to Peart, describes a rotatable sleeve assembly, allowing rotation of the ear tip in one axis, but not allowing off axis angular movement. This patent also describes an ear piece assembly including a rotatable ball, allowing rotation of the ear tip only on axis. No significant off axis angular movement is possible due to the assembly&#39;s design; and 
         [0024]    U.S. Pat. No. 2,803,308, to Di Mattia, describes a rotatable sleeve assembly, allowing rotation of the ear tip in one axis. No off axis angular movement is possible. 
         [0025]    U.S. Pat. No. 5,002,151 (Oliveira) describes (with reference to that patent&#39;s FIG. 4a) a hearing aid ear piece including the above-mentioned ball and socket assembly. However, the hearing aid is a stationary hearing aid and the ear piece is designed to remain fixed during use. The ball and socket assembly is designed to allow the ear tip to be easily attached and detached from the rest of the hearing aid, and is said to be a substitute for a bayonet attachment assembly. Oliveira thus teaches interchangeable use of a bayonet or ball and socket assembly for fixedly (but removably) attaching an ear tip to a hearing aid. 
         [0026]      FIG. 4  is a cross section drawing of an earpiece described in the Moteki patent (U.S. Pat. No. 6,514,213) in which the inner race  6   b  of a ball bearing  5   a  is mounted on earpiece tube  8   a , while the outer race  6   c  is fastened to a hub  6   a  which in turn is fastened to the ear tip  7   a . This allows the ear tip to have free rotation about the ear piece axis as hub  6   a  rolls on balls  9   a  of bearing  5   a . No provision is made for earpiece off axis movement. 
         [0027]      FIG. 5  is a cross section drawing is shown of an earpiece described in the Peart patent (U.S. Pat. No. 3,710,888). This earpiece assembly uses a sleeve  5   b  screwed onto earpiece tube  8   b . A second sleeve  6   d  is slipped over and swaged over distal end (the left end, in  FIG. 5 ) of sleeve  5   b . The swaging is loose, allowing “on axis” rotation of sleeve  6   d  over sleeve  5   b  (relative to the center axis of tube  8   b ). Sleeve  6   d  is fastened to ear tip  7   b . This allows the ear tip  7   b  and sleeve  6   d  to rotate about the center axis of earpiece tube  8   b . No provision is made for off axis movement of ear tip  7   b  or sleeve  6   d.    
         [0028]      FIG. 6  is a cross section drawing of another earpiece described in the Peart patent. This earpiece assembly uses a ball  5   c  bonded onto earpiece tube  8   c . Ear tip  7   c  is placed over the ball  5   c , with freedom to rotate relative to ball  5   c  and tube  8   c  about the earpiece&#39;s longitudinal axis. Although the design allows “on axis” rotation of ear tip  7   c  (around the center longitudinal axis of tube  8   c ), the close fit of ear tip  7   c &#39;s distal portion  9   c  around tube  8   c  would prevent significant off axis pivoting of ear tip  7   c  relative to tube  8   c.    
         [0029]    Prevention of off axis pivoting of ear tip  7   c  was evidently a deliberate design of Peart in view of Peart&#39;s teaching at col. 1, lines 16-35, that although an ear tip could be mounted with unrestricted rotatability (about all axes) relative to the user&#39;s ear canal, restricted ear tip rotatability (rotatability only about an axis parallel to the ear canal&#39;s longitudinal axis) “suffices since it substantially eliminates, completely, tangential stress on the ear canal tissues. While this permits some stress to be exerted transverse to the axis of rotation, and along it, the usual movement of the stethoscope is not in such directions as would produce these types of stress, and, further, the ear canals are less vulnerable thereto.” The present inventor has recognized that this teaching of Peart is incorrect for a number of reasons, including the reason that, in some stethoscope users, the ear canal is very sensitive in all directions of stress and sustained pressure. The present inventor has addressed stethoscope user ear comfort issues in US Patent Application Publication No. 20090321196, published Dec. 31, 2009 (entitled Asymmetric Tension Adjustment Mechanism and Head Piece including Same), and the present invention addresses such comfort issues in a very different way to be described in detail below. 
         [0030]    Peart notes at col. 1, lines 21-27, that ear tips can be connected to sound tubes “by ball and socket joints, so that when the eartips are in place in the ear canals, the axis of rotation between sound tubes and eartips can have any angular orientations whatsoever.” However, Peart does not suggest that there should be any limitation on the range in which an ear tip should be allowed to rotate about any particular axis. In contrast, the present inventor has recognized that although, for practical use, a full range of axial (“on axis”) rotation of an ear tip can be allowed over the full range (i.e., by any amount from 0 to 360 degrees about the axis of an ear piece assembly to which the ear tip is mounted), and the ear tip should be allowed significant freedom to pivot off axis as well as on axis, the ear tip&#39;s off axis deviation should typically be limited to be not be more than about ten degrees (relative to the axis of the ear piece assembly). The reason for this is that if an ear tip moves (e.g., is bent) off axis too far, it becomes cumbersome to insert into the ear canal. Additionally, it can easily fall off its socket when inadvertently rubbed up against clothing, coat pockets, or other objects. 
         [0031]    Typical embodiments of the present invention achieve desirable (substantial, but limited) ear tip off axis rotatability, and substantial (preferably unlimited) “on axis” rotatability, by splitting up the functions of ear tip rotation and off axis movement restriction. This will be further explained in detail below. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0032]    In a class of embodiments, the invention is an ear piece assembly (e.g., an ear piece for a stethoscope headpiece) configured to achieve compound axis ear tip movement in either of two ways. In some embodiments, the ear piece assembly includes an ear tip mounted as an element of a ball and socket assembly so as to have a limited range of off-axis pivoting motion (and freedom to rotate on axis). In another class of embodiments, an ear piece is designed to rotate on a shaft around the ear piece axis, while flexing slightly in the any direction orthogonal to the ear piece axis. 
         [0033]    The ball and socket assembly&#39;s configuration lends itself to movement in any direction given the constraints of its ball mount and other external limiting devices. The ball and socket assembly is easy to insert and remove for cleaning and adjusts comfortably to various shapes and sizes of ear canal entry configurations. 
         [0034]    The ear piece assembly including a shaft and a flexing ear tip portion also works well, but its ear tip may be more complex to mold than is the ear tip of the ear piece with ball and socket assembly. 
         [0035]    In a class of embodiments, the inventive earpiece assembly includes an ear tip portion (which directly interfaces with the user&#39;s ear canal) configured to be rotatable on axis (about the earpiece assembly&#39;s longitudinal axis) relative to the rest of the earpiece assembly and to have limited freedom to pivot off axis (about at least one axis that is perpendicular to the longitudinal axis) relative to the rest of the earpiece assembly. 
         [0036]    Other aspects of the invention are a headpiece (e.g., a stethoscope headpiece) or stethoscope including any embodiment of the inventive earpiece assembly, an ear piece housing body configured for use in an embodiment of the inventive earpiece assembly, and an ear tip configured for use in an embodiment of the inventive earpiece assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]      FIG. 1  shows a partial perspective view of a stethoscope with an embodiment of the inventive ear piece placed on each ear of a physician. 
           [0038]      FIG. 2  shows a partial cut away view of a typical human ear with an embodiment of the inventive ear tip in place. 
           [0039]      FIG. 3  shows diagrammatically a top view of a physician&#39;s head (with an embodiment of the inventive ear tip placed on each ear of the physician) indicating X, Y and Z coordinates referred to herein. 
           [0040]    Each of  FIGS. 4 ,  5  and  6  is a cross-sectional view of a conventional stethoscope ear piece. 
           [0041]      FIG. 7  is a partial, elevational view of a stethoscope which includes a pair of ear pieces ( 10 ). Each of ear pieces  10  is designed in accordance with a first embodiment of the invention. 
           [0042]      FIG. 8  is a side elevational view of ear piece  10  (of  FIG. 7 ) showing the basic external structure of the first embodiment of the invention. 
           [0043]      FIG. 9  is a cross-sectional view, showing the basic internal structure of the first embodiment of the invention. 
           [0044]      FIG. 10  is an exploded view of the first embodiment of the present invention. 
           [0045]      FIG. 11  is a cross sectional view of an ear piece of the first embodiment of the inventive ear tip swiveling in a downward direction. 
           [0046]      FIG. 12  is a cross sectional view of an ear piece of the first embodiment of the inventive ear tip swiveling in an upward direction. 
           [0047]      FIG. 13  shows the basic internal structure of a second embodiment of the present invention. 
           [0048]      FIG. 14  is a cross sectional view of the second embodiment of the inventive ear tip, with the ear tip swiveling in a downward direction. 
           [0049]      FIGS. 15 ,  16  and  17  show various structures and compositions of embodiments of the ear tip section of the inventive ear piece. 
           [0050]      FIGS. 18 ,  19  and  20  show various dimensional variations and compositions of embodiments of the ear tip section of the inventive ear piece. 
           [0051]      FIG. 21  is a cross section of the basic internal structure of a third embodiment of the present invention. 
           [0052]      FIG. 22  is a cross section of the basic internal structure of the third embodiment of the invention with its ear tip portion flexing downward. 
           [0053]      FIG. 23  is a cross section of the basic internal structure of a fourth embodiment of the present invention. 
           [0054]      FIG. 24  is a cross section of the basic internal structure of the fourth embodiment of the invention with the ear tip portion swiveling in a downward direction. 
           [0055]      FIG. 25  is an exploded cross sectional view of the basic internal structure of a fifth embodiment of the present invention. 
           [0056]      FIG. 26  is an assembled cross section of the basic internal structure of the fifth embodiment of the invention. 
           [0057]      FIG. 27  is a cross section of the basic internal structure of a sixth embodiment of the present invention. 
           [0058]      FIG. 28  is a cross section of the basic internal structure of a seventh embodiment of the present invention. 
           [0059]      FIG. 29  is a cross section of the basic internal structure of an eighth embodiment of the present invention. 
           [0060]      FIG. 30  is a cross section of the basic internal structure of a ninth embodiment of the present invention. 
           [0061]      FIG. 31  is a cross section of the basic internal structure of a tenth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0062]      FIG. 1  is an illustration of a physician wearing a stethoscope of the present invention showing the position of the ear piece  10  attached to the metal tube portion  11 , which connects to plastic lumen  12 .  FIG. 2  shows a close up cutaway view of the ear  4  and ear canal entrance  3  with ear piece  10  (of  FIG. 1 ) in position. Note the distortion of ear piece  10 &#39;s ear tip portion  20  at the entrance of the ear canal  3 . This is normal for soft ear tips to affect proper sealing of the ear tip  20  to the ear canal entrance  3 . Note also the angle of entry of the ear piece  10  relative to the horizontal plane. This entry angle (in the vertical plane of  FIG. 2  which is parallel to the XZ plane of  FIG. 3 ) can vary depending on the ear canal  3  entrance variations. 
         [0063]      FIG. 3  is a diagram of the top view of the physician&#39;s head  1  showing ear pieces  10  (of  FIGS. 1 and 2 ) in place. Axes X and Y (in a horizontal plane) are clearly shown in  FIG. 3 , whereas the vertical Z axis is perpendicular to the plane of  FIG. 3 . Note that the ear piece  10  is oriented (as is typical) about 10 degrees off the Y axis (in the XY plane) towards the back of the physician&#39;s ear  4  and thus his head  1 . This angle (in the horizontal XY plane) is not the angle discussed with reference to  FIG. 2  ( FIG. 2  is in a plane parallel to the XZ plane of  FIG. 3 ) but is another angle. Since the ear canal  3  is not perfectly round and the ear tip  20  is deformed in the canal  3 , it is evident that the ear tip  20  needs to be free of movement and to sit in its position during use, while the body of the ear piece  10  with its tube  11  move both rotationally (typically 0-50 degrees from chest to top of head or so) about the earpiece axis and tangentially off axis some 5 to 10 degrees or so. This is limited freedom of motion is achieved in accordance with the present invention. 
         [0064]      FIG. 7  illustrates an exemplary, typical stethoscope which includes an embodiment of the inventive ear pieces  10  (also shown in above-described  FIGS. 1-3 ). The stethoscope comprises a head piece (comprising two ear pieces  10  mounted on sound tubes  11 ), a tube assembly (hollow flexible plastic lumens  12 , transition  13 , and lumen  14 ), and chest piece  15 . Sound tubes  11  are over molded with lumens  12 . The two lumens  12  join in a “y” transition  13  which then tapers to a single lumen  14 . The single lumen  14  finally fastens to the chest piece  15  which is used for detecting body sounds by the physician. In some embodiments, the invention is a head piece (e.g., the stethoscope head piece of  FIG. 7 , or another stethoscope head piece, or audio headphones, or a telephone headset, or another non-stethoscope head piece) including at least one ear piece designed in accordance with an embodiment of the invention. 
       First Embodiment of the Present Invention 
       [0065]      FIG. 8  shows a complete ear piece assembly  10  according to a first embodiment of the present invention. It comprises a soft ear tip  20 , a main body  22  and a rear cover section  25 . Rear cover section  25  is rigidly fastened to sound tube  11 . Other parts of assembly  10  are not visible externally. 
         [0066]      FIG. 9  is a half sectional view of assembly  10  of  FIG. 8 , showing the internal parts of the assembled ear piece  10 .  FIG. 10  shows the parts of  FIG. 9  in an exploded view. Referring to  FIG. 9  and  FIG. 10 , the structure of the ear piece  10  is shown. The entire assembly comprises the following: 
         [0067]    sound tube  11 , rear cover section  25  (through which sound transducer vent hole  32  extends, as shown in  FIG. 10 ), sound transducer  24  (with wires  31  attached to transducer terminals  30 ), and gasket  23 . Optionally, transducer  24  is omitted. Additionally, the assembly of  FIGS. 9 and 10  includes ball joint unit  28  (with central through hole  26 ), ear tip  20 , and main body  22 . Optionally, a hole restrictor plug  29  is mounted in hole  26  to modify bass response of sound transducer  24 . Hole restrictor plug  29  is generally not used if the speaker (sound transducer)  24  is omitted as in the case of a passive acoustic stethoscope. At least one hole  32  is formed through the rear cover section  25  if a speaker is used. This is for purposes of back sound pressure venting. This is standard practice in the art and will not be shown in any of the other drawings although it may be present. 
         [0068]    During assembly, the sound tube  11  is inserted and bonded into rear cover section  25 , while wires  31  are passed through rear cover section  25  and sound tube  11 . Then, sound transducer  24  is fitted to the front portion of cover section  25 . Now ball joint unit  28  and gasket  23  are fitted against the front side (the side facing right in  FIG. 10 ) of cover section  25 . Next, all these are then inserted into rear section of main body  22  as shown by the dotted line and arrow facing right in  FIG. 10 . Finally, ear tip  20  is inserted onto the protruding ball of ball joint unit  28 . Preferably, spring clip  21  is positioned around ear tip  20  as shown, for increasing ear tip  20 &#39;s capability to remain in a held position against unit  28 &#39;s ball portion. As mentioned before the complete unit is shown in  FIG. 9 . 
         [0069]      FIGS. 11 and 12  illustrate the off axis movement of the ear tip  20 . The off axis pivoting movement of the ear tip  20  can be in the up direction, as shown in  FIG. 12 , or in the down direction, as shown in  FIG. 11 . Note that the proximal end portion (shroud section) of main body  22  defines a tubular cavity in which ear tip  20  can rotate (“on axis”) or pivot (“off axis”), but that the shroud section limits ear tip  20 &#39;s off axis movement at point  40  in  FIG. 11  and at point  42  in  FIG. 12 . Note also that ear tip  20  has a large diameter portion, and that the shroud section of main body  22  is configured to limit off axis angular movement of ear tip  20  relative to body  22  by engaging ear tip  20 &#39;s large diameter portion. The range of pivoting motion of ear tip  20  (relative to the ear piece assembly&#39;s longitudinal axis, labeled “X” in  FIGS. 11 and 12 ) is limited to approximately ±10 degrees (the absolute magnitude of angle θ in  FIGS. 11 and 12 , and also in  FIGS. 14 ,  22  and  24 , is approximately 10 degrees). Allowing the ear tip  20  limited freedom to move (pivot) off axis and yet not too far so as to be cumbersome to insert into the ear canal (or to rub off, etc.) is a key feature of a class of embodiments of the present invention. 
       Second Embodiment of the Present Invention 
       [0070]      FIG. 13  shows the internal structure of a second embodiment (ear piece  100 ) of the present invention. The entire assembly  100  comprises the following elements: sound tube  11 , a rear cover section (corresponding to rear cover section  25  of  FIG. 10 ), a sound transducer and gasket (corresponding to transducer  24  and gasket  23  of  FIG. 10 ), ball joint unit  128  (with a central through hole), ear tip  320 , and main body section  122 . Ear piece  100  of  FIG. 13  is similar to ear piece  10  of the first embodiment, but with its ball joint unit  128  having a hollow protrusion  129  (from its proximal end), said protrusion having a proximal opening  126 . The ear tip  320  has also been provided with a larger opening  130  (larger than the corresponding opening of ear tip  20  of  FIG. 10 ) to allow room for protrusion  129  to act as an off axis limiter for ear tip  320 . The main body section  122  can now be shorter in length or remain the same (relative to main body section  22  of  FIG. 10 ). In the  FIG. 13  embodiment, the off axis motion limitation is provided by both the main body section  122  and the protrusion  129 . The proximal end portion (shroud section) of main body section  122  defines a tubular cavity in which ear tip  320  can rotate (“on axis”) or pivot (“off axis”), but the shroud section limits this off axis movement (e.g., at point  146  in  FIG. 14 ). As shown in  FIG. 14 , protrusion  129  also limits the off axis movement of ear tip  320  (e.g., at point  46  in  FIG. 14 ). The range of off axis pivoting motion of earpiece  320  (relative to the ear piece assembly&#39;s longitudinal axis, labeled “X” in  FIG. 14 ) is limited to approximately ±10 degrees (the absolute magnitude of angle θ in  FIG. 14  is approximately 10 degrees). 
         [0071]      FIGS. 15 ,  16 , and  17  show various configurations of the ear tip included in various embodiments of the invention. 
         [0072]      FIG. 15  shows ear tip  20  (also shown in  FIGS. 9 and 10 ) with outer (proximal) opening  50 , inner opening  51 , partially spherical ball joint socket opening  52  (whose proximal side tapers toward opening  51 ), and a distal opening  53  (defined by angled entry surface  54 ) for receiving a ball joint. Ear tip  20  will typically be made of a soft material such as silicone so as to deform when placed into the ear canal. Because it is soft it is prone to falling off if handled roughly. To assist retention on an earpiece ball joint, tip  20  has a slot for receiving a split spring metal collar or hard plastic ring  21  which may be round in cross section. 
         [0073]      FIG. 16  shows an ear tip  120  with outer opening  60 , inner opening  61 , partially spherical ball joint socket opening  62  (whose proximal side tapers toward opening  61 ), and a distal opening  63  (defined by angled entry surface  64 ) for receiving a ball joint. This ear tip  120  will typically be made of a soft material such as silicone so as to deform when placed into the ear canal. Because it is soft it is prone to falling off if handled roughly. To assist retention on an earpiece ball joint, tip  120  has a slot for receiving a split spring plastic or metal collar  121  which is rectangular in cross section. 
         [0074]      FIG. 17  shows an ear tip ( 220  and  221 ) with outer opening  70 , inner opening  71 , partially spherical ball joint socket opening  72  (whose proximal side tapers toward opening  71 ), and a distal opening  73  (defined by angled entry surface  74 ) for receiving a ball joint. Portion  220  of this ear tip will typically be made of a soft material such as silicone so as to deform when placed into the ear canal. The ear tip of  FIG. 17  is a two part mold with a proximal portion  220  and a distal portion  221  (molded of a harder plastic material than is portion  220 ) to provide better holding on an earpiece ball joint. 
         [0075]      FIGS. 18 ,  19 , and  20  show various configurations of the ear tip distal openings  73 ,  83  and  93  of ear tips  420 ,  320 , and  220 / 221 , respectively. 
         [0076]    Referring to  FIG. 18 , the preferred diameter of the partially spherical ball joint socket opening  82  of ear tip  420  should generally be of the same diameter as the ball of the ball joint unit  28 . The smallest-diameter portion of opening  83  should generally be 0.7 times the diameter of the ball of unit  28  (illustrated as “x” dimension in  FIG. 18 ). This creates a ball joint that is easy to push on and is adequate. 
         [0077]    Referring to  FIG. 19 , the preferred diameter of the partially spherical ball joint socket opening  92  of ear tip  320  should generally be of the same diameter as the ball of the ball joint unit  328  (unit  328  differs from ball joint unit  28  by having a smaller diameter neck portion  330  and a smaller diameter central passage. The smallest-diameter portion of opening  93  can be 0.5 times the diameter of the ball of unit  328  (illustrated as “x” dimension in  FIG. 19 ). This creates a ball joint that is harder to push on and has better retention. However, the neck portion  330  of ball joint unit  328  can be rather flimsy and prone to breaking unless it is made of metal. The preferred material for all the ball joint units is plastic. Metal is more expensive. 
         [0078]    Referring to  FIG. 20 , the preferred diameter of the partially spherical ball joint socket opening  102  of ear tip  220 ,  221  should generally be of the same diameter as the ball of the ball joint unit  28 . The smallest-diameter portion of opening  73  should generally be 0.7 times the diameter of the ball of unit  28 . However as previously shown in  FIG. 17  this ear tip unit  220 ,  221  is molded with a harder distal portion  221 . In this case the dimension of the opening  73  is determined experimentally depending on the material used for distal portion  221 . Also the lubricity of the plastics used determines the ease of rotation and swiveling of the ball and socket assembly. Teflon for the ball portion has shown the best results. 
       Third Embodiment of the Present Invention 
       [0079]      FIGS. 21 and 22  show a cross sectional view of a third embodiment (ear piece assembly  200 ) of the present invention. Ear piece assembly  200  includes main body section  522  (whose proximal end portion  522 A defines a generally cylindrical shroud), bearing element  529  within section  522 , and ear tip  520  fitted onto element  529 . Ear piece assembly  200  uses neither a relatively long sleeve nor a ball and socket joint. It does use element  529 , which has a rather short hollow neck  530  and a hollow, partial conical (truncated conical), support portion  528  at its proximal end, in place of a ball joint unit. Referring to  FIG. 21 , ear tip  520  of assembly  200  is designed to both rotate (rotate “on axis” about the assembly&#39;s longitudinal axis) and swivel (flex “off axis” relative to the assembly&#39;s longitudinal axis) relative to element  529 . The sound seal is by a snug fitting of the ear tip&#39;s distal portion  524  to the neck  530  of element  529 . The ear tip  520  is ribbed at portion  550  (between distal portion  524  and the rest of ear tip  520 ). The ribbed shape of portion  550  provides further ease of flexing off axis. 
         [0080]    Referring to  FIG. 22 , ear tip  520  is shown in an off axis position. Off axis flexural pivoting movement of ear tip  520  (relative to element  529 ) is provided both by movement of ear tip  520 &#39;s flexible distal portion  524  relative to element  529  and by flexing of ribbed portion  550 . End portion  522 A of ear tip housing  522  defines a tubular cavity in which ear tip  520  can rotate (“on axis”) or pivot (“off axis”), but limits this off axis pivoting (e.g., as shown by shroud  522 A&#39;s engagement with ear tip  520  at location  560 ). Cavity  523  within housing  522  is shown empty in  FIGS. 21 and 22 . It can house a sound transducer assembly for active stethoscopes or be fitted with an appropriate plastic bushing if a passive acoustic stethoscope is used. 
         [0081]    In variations on the  FIG. 21-22  embodiment, element  529  is replaced by another bearing element having a rotationally symmetric support portion (e.g., a rotationally symmetric support portion having a shape other than the shape of partial conical end portion  528  of element  529 ), said bearing element being configured to support an ear tip that has been fitted onto it such that the ear tip has freedom to rotate (“on axis,” where “axis” here denotes the axis of symmetry of the support portion) relative to the support portion. The ear tip should also have freedom to flex (“off axis”) relative to the support portion (and relative to an ear tip housing in which the bearing element is positioned). 
       Fourth Embodiment of the Present Invention 
       [0082]      FIGS. 23 and 24  show a cross sectional view of a fourth embodiment (ear piece assembly  300 ) of the present invention. Ear piece assembly  300  includes main body  322  (whose proximal end portion  324  defines a generally cylindrical shroud), element  628  rotatably mounted within body  322 , and ear tip  620  attached (fastened or molded) onto element  628 . 
         [0083]      FIG. 23  shows a one piece molded housing  322  with a partial socket  323 . Element  628  has a ball shaped proximal end, and is hollow (with an elongated shaft extending through it). When the ball shaped end portion of element  628  is pressed into the socket portion  323 , it forms a rotating and swiveling ear piece assembly. If desired, an optional sealing “O” ring  360  provides a better acoustic seal between element  628  and main body  322 . Although this sample embodiment is useful in an acoustic stethoscope, those in the art will appreciated that it could also be designed for provision of an acoustic transducer (e.g., for use in an active stethoscope). 
         [0084]      FIG. 24  shows ear piece assembly  300  with ear piece  620  in an off axis position. Limitation of off axis pivoting of ear tip  620  is provided by shroud  324  of body  322  (as shown by shroud  324 &#39;s engagement with ear tip  620  at location  350 ). 
       Fifth Embodiment of the Present Invention 
       [0085]      FIGS. 25 ,  26  and  27  show a cross sectional view of a fifth embodiment (ear piece assembly  500 ) of the present invention. Ear piece assembly  500  includes main body (housing)  422  (whose distal end is attached to sound tube  11  and whose proximal end portion defines a generally cylindrical shroud), and ball joint unit  428  and ear tip  120  rotatably mounted within body  422  (with ear tip  120  attached to the ball end of unit  428 ). 
         [0086]      FIG. 25  shows a cross sectional exploded view of ear piece assembly  500 . In this exemplary embodiment, housing  422  is a one piece unit (once again having a capability of also housing a sound transducer). As shown, however, plastic bushing  421  is shown within housing  422  in a position for engaging distal flange  449  of unit  428 , so as to allow on axis of rotation of unit  428  (with ear tip  120  fixedly attached thereto) relative to bushing  421  and housing  422 . Ear tip housing  422  is provided with an inclined, inner very slight conical surface  447  for engaging the distal end portion of ear tip  120 . This conical incline is preferably only about 2 to 3 degrees (relative to assembly  500 &#39;s longitudinal axis). Immediately distal to surface  447  is a slightly larger diameter portion  448  of housing  422 , designed to receive flange  449  of ball joint unit  428  (to snap unit  428  into housing  422 ). Portion  448  has an edge surface  451  at the intersection of portion  448  with surface  447 . 
         [0087]      FIG. 26  shows assembly  500  when it has been assembled. Note that sharply stepped edge surface  451  of housing  422  retains the ball joint unit  428 . Ear tip  120  has been inserted over the ball end of unit  428  (with the ball end of unit  428  retained within a corresponding inner socket portion of ear tip  120  as shown in  FIG. 26 . Operation of assembly  500  is identical to that of other ear piece assemblies described and shown herein. Limitation of off axis pivoting of ear tip  120  is provided by the proximal shroud portion of housing  422  (the shroud engages ear tip  120  at the each limit of the off axis pivoting). 
       Sixth Embodiment of the Present Invention 
       [0088]      FIG. 27  shows a cross sectional view of a sixth embodiment (ear piece assembly  600 ) of the invention. Assembly  600  includes a fully molded housing and ball unit  622 . Unit  622  functions as both an ear tip housing and a ball section, with the ear tip housing and ball sections integrated together as one unit. Ear tip  120  is simply pushed on to the ball end of unit  622 . This is the simplest unit designed for passive acoustic applications. Electronic, or active, stethoscopes can also use ear piece assemblies of this design if a sound transducer is placed elsewhere in the sound path, such as in the area  13  of  FIG. 7  for example. This has been done many times in the art. With appropriate plastic injection molding techniques, this one piece unit could be designed to hold a sound transducer also (e.g., if sound tube  11 , for example, is modified for a larger diameter at its proximal end). In this case, unit  622  could have a distal portion with a hole large enough to hold a sound transducer and the modified tube  11 . Operation of assembly  600  is identical to that of other ear piece assemblies described and shown herein. Limitation of off axis pivoting of ear tip  120  is provided by the proximal shroud portion of unit  622  (the shroud engages ear tip  120  at the each limit of the off axis pivoting). 
       Seventh Embodiment of the Present Invention 
       [0089]      FIG. 28  shows a cross sectional view of a seventh embodiment (ear piece assembly  700 ) of the invention. Assembly  700  can be employed for retro-fitting a common type of commercial stethoscope. Referring to  FIG. 28 , assembly  700  includes ear tip housing  722  fitted with a threaded distal portion  723  configured to receive threaded proximal portion  724  of sound tube  111  (so that housing  722  can be screwed onto the proximal end of tube  111 ). Fitted into the proximal end of housing  722  is ball joint unit  28  which receives ear tip  120 . Limitation of off axis pivoting of ear tip  120  is provided by the proximal shroud portion of housing  722  (the shroud engages ear tip  120  at the each limit of the off axis pivoting). 
       Eighth Embodiment of the Present Invention 
       [0090]      FIG. 29  shows a cross sectional view of an eighth embodiment (ear piece assembly  800 ) of the invention. Assembly  800  can be employed for retro-fitting a second common type of commercial stethoscope. Referring to  FIG. 29 , assembly  800  includes ear tip housing  822  fitted with a second style portion  823  configured to receive second style proximal portion  824  of sound tube  211  (so that housing  822  can be attached onto the proximal end of tube  211 ). Fitted into proximal end of housing  822  is ball joint unit  28  which receives ear tip  120 . Limitation of off axis pivoting of ear tip  120  is provided by the proximal shroud portion of housing  822  (the shroud engages ear tip  120  at the each limit of the off axis pivoting). 
       Ninth Embodiment of the Present Invention 
       [0091]      FIG. 30  shows a cross sectional view of a ninth embodiment (ear piece assembly  900 ) of the invention. Assembly  900  can be employed for retro-fitting a third common type of commercial stethoscope. Referring to  FIG. 30 , assembly  900  includes ear tip housing  922  fitted with a third style portion  923  configured to receive third style proximal portion  924  of sound tube  311  (so that housing  922  can be attached onto the proximal end of tube  311 ). Proximal ball joint portion unit  928  of housing  922  receives ear tip  120 . Limitation of off axis pivoting of ear tip  120  is provided by the proximal shroud portion  929  of housing  922  (shroud  929  engages ear tip  120  at the each limit of the off axis pivoting). 
       Tenth Embodiment of the Present Invention 
       [0092]      FIG. 31  shows a cross sectional view of a tenth embodiment (ear piece assembly  1000 ) of the invention. Assembly  1000  can be employed for retro-fitting a fourth common type of commercial stethoscope. Referring to  FIG. 31 , assembly  1000  includes ear tip housing  1022  fitted with a fourth style portion  1023  configured to receive fourth style proximal portion  1024  of sound tube  411  (so that housing  1022  can be attached onto the proximal end of tube  411 ). Proximal ball joint portion unit  1028  of housing  1022  receives ear tip  120 . Limitation of off axis pivoting of ear tip  120  is provided by the proximal shroud portion  1029  of housing  1022  (shroud  1029  engages ear tip  120  at the each limit of the off axis pivoting). 
         [0093]    The materials available for the present invention are many. For example typical embodiments of the ear piece housing can be metal (e.g., aluminum) or plastic (e.g., polycarbonate or nylon). Typical embodiments of the ear tip can be silicone or polyurethane or another soft material. Typical embodiments of the ball joint can be made of any suitable plastic or metal. Teflon has been used successfully for the ball joint. Typical embodiments the rotating and swivel unit (e.g., element  529  of  FIGS. 21 and 22 ) are preferably made of plastic for cost reasons, but could alternatively be made of metal. 
         [0094]    In embodiments in which the ear piece housing has a main housing section, the main housing section can be made as one uniform piece, or as several pieces coupled together, and can be made of any of various materials (e.g., plastic, metal, or a composite material. 
         [0095]    Some embodiments of the invention are or include a ball joint unit, said ball joint unit including: a flange shaped distal section with a hole through axial center for sound propagation; a short cylindrical shaft center section with a hole through axial center for sound propagation; and a ball proximal section with a hole through axial center for sound propagation, where the holes from the distal end of said flange section through to the proximal end of said ball section are generally one through hole. 
         [0096]    Some embodiments of the invention are or include a ball joint unit, said ball joint unit including: a flange shaped distal section with a hole through axial center for sound propagation; a short cylindrical shaft center section with a hole through axial center for sound propagation; a ball central section with a hole through axial center for sound propagation; and a tubular section affixed to said proximal end of ball central section with a hole through axial center for sound propagation, wherein the holes from the distal end of said flange section through to the proximal end of said tubular section are generally one through hole. 
         [0097]    Some embodiments of the invention are or include a conical (e.g., blunt or truncated conical) ended shaft unit, said conical ended shaft unit including: a flange shaped distal section with a hole through axial center for sound propagation; a short cylindrical shaft center section with a hole through axial center for sound propagation; and a blunt conical proximal section with the lesser diameter of said conical section facing the proximal direction with a hole through axial center for sound propagation, wherein the larger diameter conical section faces in the distal direction, the larger diameter conical section is substantially larger in diameter than the shaft section, the smaller diameter conical section is approximately the same diameter as the shaft section, and the holes from the distal end of said flange section through to the proximal end of said conical section are generally one through hole. 
         [0098]    The present invention is universally applicable to most existing stethoscopes and dictation headsets on the market, and is also useful to implement ear piece assemblies of other headsets. 
         [0099]    In terms of limiting the off axis movement of the ear tip (of the inventive assembly) and its tendencies to be rubbed off during use or stuffing into a pocket on a surgical gown, for example, the present inventor has not limited his scope of possible design variations. Rather he has presented in this teaching some of the most practical designs. Key to the teaching of this disclosure is ear tip&#39;s freedom to undergo limited “off axis” movement (and preferably also, free “on axis” rotation). Those of ordinary skill in the art could readily devise other means to limit “off axis” movement and provide ear tip retention, given the teaching of this disclosure. 
         [0100]    Although the descriptions above contain many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Thus the scope of the invention should be determined by the appended claims and their legal equivalents rather than by the examples provided.