fig1 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 . fig2 shows a close up cutaway view of the ear 4 and ear canal entrance 3 with ear piece 10 ( of fig1 ) 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 fig2 which is parallel to the xz plane of fig3 ) can vary depending on the ear canal 3 entrance variations . fig3 is a diagram of the top view of the physician &# 39 ; s head 1 showing ear pieces 10 ( of fig1 and 2 ) in place . axes x and y ( in a horizontal plane ) are clearly shown in fig3 , whereas the vertical z axis is perpendicular to the plane of fig3 . 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 fig2 ( fig2 is in a plane parallel to the xz plane of fig3 ) 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 . fig7 illustrates an exemplary , typical stethoscope which includes an embodiment of the inventive ear pieces 10 ( also shown in above - described fig1 - 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 fig7 , 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 . fig8 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 . fig9 is a half sectional view of assembly 10 of fig8 , showing the internal parts of the assembled ear piece 10 . fig1 shows the parts of fig9 in an exploded view . referring to fig9 and fig1 , the structure of the ear piece 10 is shown . the entire assembly comprises the following : sound tube 11 , rear cover section 25 ( through which sound transducer vent hole 32 extends , as shown in fig1 ), sound transducer 24 ( with wires 31 attached to transducer terminals 30 ), and gasket 23 . optionally , transducer 24 is omitted . additionally , the assembly of fig9 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 . 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 fig1 ) 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 fig1 . 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 fig9 . fig1 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 fig1 , or in the down direction , as shown in fig1 . 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 fig1 and at point 42 in fig1 . 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 fig1 and 12 ) is limited to approximately ± 10 degrees ( the absolute magnitude of angle θ in fig1 and 12 , and also in fig1 , 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 . fig1 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 fig1 ), a sound transducer and gasket ( corresponding to transducer 24 and gasket 23 of fig1 ), ball joint unit 128 ( with a central through hole ), ear tip 320 , and main body section 122 . ear piece 100 of fig1 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 fig1 ) 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 fig1 ). in the fig1 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 fig1 ). as shown in fig1 , protrusion 129 also limits the off axis movement of ear tip 320 ( e . g ., at point 46 in fig1 ). the range of off axis pivoting motion of earpiece 320 ( relative to the ear piece assembly &# 39 ; s longitudinal axis , labeled “ x ” in fig1 ) is limited to approximately ± 10 degrees ( the absolute magnitude of angle θ in fig1 is approximately 10 degrees ). fig1 , 16 , and 17 show various configurations of the ear tip included in various embodiments of the invention . fig1 shows ear tip 20 ( also shown in fig9 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 . fig1 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 . fig1 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 fig1 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 . fig1 , 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 . referring to fig1 , 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 fig1 ). this creates a ball joint that is easy to push on and is adequate . referring to fig1 , 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 fig1 ). 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 . referring to fig2 , 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 fig1 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 . fig2 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 fig2 , 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 . referring to fig2 , 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 fig2 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 . in variations on the fig2 - 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 ). fig2 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 . fig2 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 ). fig2 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 ). fig2 , 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 ). fig2 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 . fig2 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 fig2 . 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 ). fig2 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 fig7 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 ). fig2 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 fig2 , 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 ). fig2 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 fig2 , 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 ). fig3 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 fig3 , 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 ). fig3 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 fig3 , 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 ). 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 fig2 and 22 ) are preferably made of plastic for cost reasons , but could alternatively be made of metal . 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 . 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 . 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 . 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 . 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 . 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 . 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 .
an ear piece assembly designed for a stethoscope or other headpiece , and configured to allow rotation of an ear tip of the assembly about a central axis and to allow limited off axis movement of the ear tip . 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 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 .