Background of the Invention
Stethoscopes are known having a double-headed body contact piece provided at one axial end thereof with a larger-diameter auscultation head and provided at the other axial end thereof with a smaller-diameter auscultation head. Typically, one head is for example used for auscultation of lower-frequency body sounds and the other for auscultation of higher-frequency body sounds.
In configurations where the body contact piece is provided with first and second acoustic connector portions which are respectively in acoustic communication with the first head and with the second head, the examining physician when he wishes to switch over from one auscultation head to the other can disconnect the stethoscope-tube attachment from one of the body contact piece's two acoustic connector portions and connect the tube attachment instead to the other acoustic connector portion, although this is of course inconvenient. The stethoscope-tube attachment may be of the single-acoustic-passage type leading from the selected acoustic connector portion of the body contact piece to a single earpiece which the physician wears on one ear during auscultation. Or else, a two-acoustic-passage stethoscope-tube attachment can be employed. The two acoustic-signal-transmitting passages of the latter are for example connected to the selected one of the body contact piece's two acoustic connector portions by means of a Y-type stethoscope-tube portion or by means of a Y-type connector fixture; the two acoustic-signal-transmitting passages of the stethoscope-tube attachment are then typically connected at their other ends to respective ones of the two earpieces of a binaural headset.
A further possibility is to provide the body contact piece with a single acoustic connector portion which acoustically communicates, internally of the body contact piece, with the ausculation chamber of a selected one of the two auscultation heads, the selection of one head or the other being performed by means of a manually activated switchover mechanism. In such case the body contact piece's single acoustic connector portion can, as before, be connected to a single-acoustic-passage stethoscope-tube attachment leading to a single earpiece, or can be connected via a Y-type tube portion or Y-type connector fixture to the two passages of a two-acoustic-passage stethoscope-tube attachment whose two acoustic-signal-transmitting passages lead to respective ones of the two earpieces of a binaural headset.
West German published patent application ("Offenlegungsschrift") No. 2 204 730 discloses a modification of the configuration set forth immediately above. Instead of the body contact piece having a single acoustic connector portion which acoustically communicates, internally of the body contact piece, with the selected one of the two auscultation heads, the body contact piece is provided with two acoustic connector portions, each connected to a respective passage of a two-acoustic-passage stethoscope-tube attachment. However, the two acoustic connector portions on the body contact piece are, internally of the latter, acoustically connected to each other. Accordingly, the use of two acoustic connector portions instead of a single acoustic connector portion merely serves to establish a conventional Y-junction for the two stethoscope-tube passages, namely now internally of the body contact piece, instead of establishing such Y-junction externally thereof by means of the conventional Y-type tube portion or Y-type connector fixture.
Summary of the Invention
It is a main object of the invention to provide a stethoscope having a double-headed body contact piece that is provided with an internal switchover mechanism of fundamentally different acoustical configuration than in the prior art.
In accordance with the invention the double-headed body contact piece of the stethoscope is provided with two acoustic connector portions, each connected or connectable to a respective acoustic-signal-transmitting passage of a two-acoustic-passage stethoscope-tube attachment. Furthermore, the body contact piece is provided with an externally activatable internal switchover mechanism which is designed in such a manner that, in one setting, it causes two distinguishable acoustic output signals to be produced, one such signal at one acoustic connector portion and the other such signal at the other acoustic connector portion, with these two distinguishable acoustic output signals being both furnished from one of the two heads of the double-headed body contact piece.
This configuration for the internal switchover mechanism of the body contact piece can be of particular advantage if one of the latter's two auscultation heads is a differential-auscultation head, for example a two-chamber auscultation head. In that event, when the switchover mechanism is moved to the setting which selects the differential-auscultation head, a first acoustic output signal is produced at the first acoustic connector portion of the body contact piece, furnished from one chamber of the differential head; and a distinguishable second acoustic output signal is produced at the other acoustic connector portion of the body contact piece, furnished from the differential head's other chamber. These two distinguishable acoustic signals are then transmitted via respective acoustic-signal-transmitting passages of a two-acoustic-passage stethoscope-tube attachment.
The other head of the double-headed body contact piece can for example be a non-differential auscultation head. In that event, the internal switchover mechanism of the body contact piece can be so designed that the two acoustic passages of the stethoscope-tube attachment receive identical acoustic output signals at both acoustic connector portions of the body contact piece.
The differential-auscultation head may for example be the larger-diameter head of the double-headed body contact piece, and the non-differential auscultation head may be the smaller-diameter head thereof.
Preferably, the internal switchover mechanism of the stethoscope's body contact piece is a rotary mechanism that can be manually rotated from the exterior of the body contact piece. Such a configuration for the switchover mechanism is simple to operate manually and is very sturdy. Also, such a design is ergonomically advantageous, and the exterior of the body contact piece can for example be provided with simple markings or indicia to indicate the present setting of the switchover mechanism.
Preferably, the rotatable switchover mechanism has a planar axial end surface which is in sliding contact with the planar axial end surface of one of the two auscultation heads, or in sliding contact with the planar axial end surface of an intermediate member connected with one of the two heads. With such a configuration, the establishment and disestablishment of the various internal acoustical connections can be accomplished by registration or non-registration of acoustic passages which are provided in the rotary switchover mechanism and in such head or intermediate member and which extend to the plane of said planar axial end surfaces. Such a design tends to simplify the geometry of the acoustic connections established at such plane and, as a result, tends to greatly reduce losses in the strength or energy of the acoustic signals to be transmitted. Loss of signal strength or energy also tends to be minimized if the two acoustic connector portions for the stethoscope-tube attachment are provided on the rotating switchover mechanism, because the latter is located axially in between the two auscultation heads.
In a particularly preferred embodiment of the invention, the switchover mechanism has at least one first setting and at least one second setting. When the first setting is selected then, by means of passages internal to the body contact piece, the resulting acoustic connection leading from the single chamber of the non-differential head to the first acoustic connector portion, and the acoustic connection leading from the same chamber of the same head to the second acoustic connector portion, have geometries which are identical or else at least equivalent to each other (e.g. are mirror-symmetrical to each other) and furthermore have the same dimensions, so that these two acoustic connections be acoustically equivalent to each other. Likewise, when the second setting is selected, the resulting acoustic connecting leading from one of the two chambers of the differential-auscultation head to the first acoustic connector portion, and the acoustic connection leading from the other chamber of the differential head to the other acoustic connector portion, have geometries which are identical or at least equivalent to each other (e.g. mirror-symmetrical to each other) and furthermore have the same dimensions, so that these two acoustic connections likewise be acoustically equivalent to each other.
Further advantageous features of the invention will best be understood from the following description of a preferred embodiment when considered in conjunction with the accompanying drawing, and are also set forth in various ones of the dependent claims. It is noted that the preferred embodiment shown and described herein is offered merely in the sense of a concrete embodiment of the inventive concepts and for purposes of explanation and is not to be understood as constituting the only stethoscope design encompassed within the scope of the present invention.
Brief Description of the Drawing
FIG. 1 is a side view of the body contact piece of an exemplary embodying the present invention;
FIG. 2 is a top view looking down upon the body contact piece of FIG. 1, the two-acoustic-passage stethoscope-tube attachment be visible in this view;
FIG. 3 is a sectional view through the body contact piece, the section being taken along line III--III of FIG. 2, the switchover mechanism of the stethoscope being in part shown not sectioned;
FIG. 4 is an axial end view of the body contact piece, seen in the direction of arrow A in FIG. 3;
FIG. 5 is a analogous to FIG. 3, but showing the switchover mechanism in a setting thereof different from the one shown in FIG. 3;
FIG. 6 is a sectional view taken along section line VI--VI of FIG. 5;
FIG. 7 is a side view of the switchover mechanism's rotary switchover member, shown facing out of the picture plane with the same orientation as in FIGS. 3 and 5, and viewed in the direction of arrow B of FIG. 8;
FIG 8 is a sectional view, taken along section line VIII--VIII of FIG. 9;
FIG. 9 is a top axial end view of the rotary switchover member, as seen in the direction of arrow C of FIG. 8; and
FIG. 10 is a sectional view through the switchover member, taken along a sectioning plane that is parallel to and approximately midway between the two axial end faces of the switchover member.
Description of the Preferred Embodiment
FIGS. 1-3 depict the body contact piece of a stethoscope in accordance with the invention. As shown best in FIG. 2, the body contact piece 10 is acoustically connected to the two acoustic passages of a two-acoustic-passage stethoscope-tube attachment 11, 12. At the other end of stethoscope-tube attachment 11, 12 the latter's two acoustic passages are each acoustically connected to a respective one of the two earpieces of a (non-illustrated) binaural headset.
The body contact piece 10 includes a first, non-differential auscultation head 13 of smaller diameter at whose outer periphery is provided an annular groove 14 in which an O-ring 15 is secured, in order to be able to press the contact piece against the surface of a patient's body in sound-tight manner. The acoustic chamber 16 of this first auscultation head 13 merges into a central passage 17 from which latter, as shown in FIG. 5, two lateral passages 18 branch off. These two lateral passages 18 extend radially outwards through to the outer periphery of a cylindrical head-interconnecting portion 21. The latter near its bottom end 19 (FIG. 3) is permanently connected, e.g. by press-fitting, to a larger-diameter, second, differential-auscultation head 22, in order to establish a fixed relationship between the angular position of the smaller-diameter first head 13 and the angular position of the larger-diameter second head 22.
As shown in FIGS. 3 and 4, the second, differential-auscultation head 22 has two spherical or paraboidal acoustic chambers 23, 24, whose geometric centers or foci are spaced from each other more than ten millimeters. The two acoustic chambers 23, 24 of the larger-diameter, differential-auscultation head 22 pick up body sounds from two distinguishable auscultation locations. The shapes and arrangement of the two chambers 23, 24 are pictorially defined in FIGS. 3 and 4 and, inasmuch as differential-auscultation heads are in themselves well known in the art, need not be described in further detail herein. Acoustic-signal-transmitting passages 25, 26 lead from respective ones of the two acoustic chambers 23, 24 to a planar control surface 27 (FIG. 6) constituted by the back axial end face of second auscultation head 22. Control surface 27 is in addition provided with an annular groove 28 which accommodates an O-ring 29 made of polytetrafluoroethylene (PTFE). Similarly, the planar back axial end face 32 of first auscultation head 13 is provided with an annular groove 33 which accommodates an O-ring 34 made of PTFE. It will be understood that the grooves 28, 33 could be of other, i.e. non-circular, shapes. The O-rings 29, 34 serve chiefly to make the rotary sliding action of the axial end faces of an annular switchover member 37 between and against the two axial end surfaces 27 and 32 as low-friction and greased-seeming as possible. In addition, the O-rings 29, 34 prevent undesirable penetration of ambient sound into the interior of the auscultation heads and, conversely, prevent acoustic signal energy within the auscultation heads from escaping to the exterior as lost signal energy. The differential-auscultation head 22 is threaded at it external periphery so that a conventional diaphragm carrier with a diaphragm 41 can be screwed onto the head's front axial end. Additionally, the front axial end of head 22 is provided with an annular, planar support surface 39 for the diaphragm 41, to help retain the shape of the latter and prevent diaphragm deformation.
The rotary switchover member 37 is shown in detail in FIGS. 7-10. It is provided with first and second internally threaded, multi-diameter acoustic connector portions 46, 47 (FIGS. 7 and 10), the first and second acoustic connector portions 46, 47 receiving respective screwed-in tube connectors 44, 45 (see FIG. 2) and at their inward, smaller-diameter ends having the form of acoustic passages internal to the switchover member 37. These open into respective ones of two diametrically opposite axial passages 48, 49, communicating with the latter at a location roughly midway between the two axial end faces of the switchover member 37. The two axial passages 48, 49 extend all the way through from the one axial end face 54 to the other axial end face 55 of the switchover member 37, parallel to a cylindrical, central passage 50 internal to member 37. The diameter of central passage 50 approximately corresponds to the external diameter of the earlier-mentioned head-interconnecting portion 21, with the annular switchover member 37 being mounted on the head-interconnecting portion 21 in a manner permitting relative rotation between portion 21 and member 37. When such relative rotation is performed, the earlier-mentioned axial end faces, sliding in rotary fashion over each other, serve as control or valve surfaces
As shown in FIGS. 8 and 9, the through-passages 48, 49 communicate with central passage 50 via the intermediary of respective ones of the two short, radial passages 52 and 53. The angular width of each of the two radial passages 52, 53, measured at the periphery of central passage 50, is approximately 30.degree.. As can be seen in FIG. 9, the two short radial passages 52, 53 extend radially to join the central internal passage 50 with the two through-passages 48, 49. Likewise as shown in FIG. 9, each radial passage 52 or 53 is provided in the form of a surface recess in the axial end face 54 of switchover member 37, being recessed into such surface by an axial distance equal (as shown in FIG. 8) to a fraction of the axial length of the central internal passage 50, in this example approximately one-third the axial length of passage 50.
FIG. 3 depicts the body contact piece with the jointly rotatable auscultation heads 13, 22 in one angular setting relative to the switchover member 37. In this angular setting, the two diametrically opposite, radially extending passages 18 in head-interconnecting portion 21 do not register with the two diametrically opposite, radially extending passages 52, 53 in switchover member 37. In this setting, the diameter joining the two passages 18 is located perpendicular to the diameter joining the two passages 52, 53, and the radially outer ends of the two passages 18 of head-interconnecting portion 21 are sealed closed by the peripheral surface of the central passage 50 of switchover member 37. As a result, no acoustic connection is established between the auscultation chamber 16 of smaller-diameter head 13 and the acoustic connector portions 46, 47.
On the other hand, in this FIG. 3 setting, each of the two chambers 23, 24 of larger-diameter head 22 is acoustically connected to a respective one of the two acoustic connector portions 46, 47, as follows: Axial passage 25 in head 22 register with the axial passage 48 in switchover member 37, these two axial passages being of substantially identical diameter, thereby establishing communication between chamber 23 and passage 48. Axial passage 48, in turn (and as shown in FIG. 10) is permanently in acoustic communication with the acoustic connector portion 46 of switchover member 37, the acoustic connector portion 46 being in permanent communication with stethoscope-tube end portion 11 (compare FIG. 2). Similarly, axial passage 26 in larger-diameter head 22 registers with axial passage 49 of switchover member 37, thereby connecting the chamber 24 to passage 49, and (as shown in FIG. 10), axial passage 49 of switchover member 37 is in permanent communication with acoustic connector portion 47 of member 37, portion 47 being in permanent communication with stethoscope-tube end portion 12.
In this way, the examining physician hears in one of his two earpieces the body sounds as picked up by chamber 23, whereas in his other earpiece the body sounds as picked up by chamber 24, so that the two-chamber head 22 enables him to perform a differential auscultation.
FIG. 5 depicts the body contact piece with the jointly rotatable auscultation heads 13, 22 shown in a different angular setting relative to the switchover member 37. In this angular setting, the two diametrically opposite, axially extending passages 25, 26 of larger-diameter head 22 are not in register with the two axially extending, diametrically opposite passages 48, 49 in switchover member 37; instead the axial passages 25, 26 of head 22 are sealed closed at their rear ends by the axial end face 55 of switchover member 37 (numeral 55 is shown in e.g. FIG. 8). On the other hand, in this FIG. 5 setting, the two radially extending, diametrically opposite passages 18 in head-interconnecting portion 21 register with respective ones of the two short radially extending, diametrically opposite passages 52, 53 of switchover member 37, thus establishing an acoustic connection between chamber 16 of head 13 and the control passages 52, 53. Because the passages 52, 53 (as shown in FIG. 9) permanently communicate with the two axial passages 48, 49 in switchover member 37, and because the two axial passages 48, 49 are in permanent communication with the acoustic connector portions 46 and 47, it follows that the chamber 16 of auscultation head 13 is now in acoustic communication with both stethoscope-tube end portions 11 and 12 (shown in FIG. 2). In this situation, the examining physician hears the body sounds picked up by chamber 16 in both his two earpieces, and identically in the two earpieces, i e., without any differential action. In FIG. 5, the two arrows 60 indicate how the self-same body sounds picked up by chamber 16 are split and pass through the lateral passages 18, then through the short radially extending passages 52, 53, from there into the two axially extending through-passages 48, 49 (shown only by broken lines), and from the latter to the two acoustic connector portions 46, 47 (compare FIG. 7) of switchover member 37.
In this way, depending upon the angular setting of the jointly rotatable auscultation heads 13, 22 and the switchover member 37 relative to each other, there is established, either.
(1) an acoustic connection leading from the single chamber 16 of the first, non-differential head 13 to the first acoustic connector portion 46, and another acoustic connection leading from the same head chamber 16 to the second acoustic connector portion 47; or
(2) an acoustic connection leading from one chamber 23 of the pair of chambers 23, 24 of the second, differential-auscultation head 22 to the first acoustic connector portion 46, and another acoustic connection leading from the other chamber 24 of the head 22 to the second acoustic connector portion 47.
In the illustrated embodiment it is particularly advantageous that the two acoustic connections set forth at (1) above are, although not geometrically identical, at least geometrically equivalent to each other and, furthermore, have the same dimensions so as to be acoustically equivalent to each other. Likewise, the two acoustic connections set forth at (2) above are, although not geometrically identical, at least geometrically equivalent to each other and, furthermore, have the same dimensions so as to be likewise acoustically equivalent to each other.
This is achieved in the illustrated embodiment because the two acoustic connections set forth at (1) above are mirror-symmetrical to each other with respect to a symmetry plane that (as considered in e.g. FIG. 10) is a horizontal diametral plane (i.e. a diametral plane which is located equidistant between the two acoustic connector portions 46, 47. Likewise, the two acoustic connections set forth at (2) above are mirror-symmetrical to each other with respect to this symmetry plane.
It will be understood, however, that such acoustic equivalence can be established by an arrangement of internal passages different from the particular arrangement of internal passages employed in the particular embodiment described and shown herein.
As indicated in FIG. 1, indicia 61 can be provided on the body contact piece 10 to indicate to the user which of the two heads 13, 22 is presently in acoustic communication with the two tube end portions 11, 12. However, in actual use, the physician will often place the desired one of the two heads 13, 22 against the surface of the patient's body and then, without considering the indicia 61, will merely rotate the switchover member 37 until he begins to hear body sounds. To facilitate selection of settings, the switchover member 37 can click into place in any of four different angular settings. The click action is achieved by means of a blind bore 65 (see FIG. 8) provided in switchover member 37, the bore 65 accommodating a click ball 67 biased by a spring 66. The back axial end face 32 of the non-differential head 13 is provided with four recesses 68 spaced one from the next by 90.degree., two of these recesses 68 being visible in each of FIGS. 3 and 5. When switchover member 37 is rotated to one of its four possible angular settings, spring-biased click ball 67 enters into the corresponding recess 68 and with a definite but limited force resists further rotation of member 37.
Summarizing, in the exemplary embodiment illustrated herein, the switchover member 37, in combination with (see FIG. 8) the blind bore 65 formed therein and containing the biasing spring 66 for the click ball 67, constitutes a switchover mechanism. Switchover mechanism 37, 65-67 is operative for establishing acoustic connections from predetermined ones of the auscultation chambers 16 and 23, 24 to the acoustic connector portions 46, 47; for acoustically isolating the acoustic connector portions 46, 47 from predetermined ones of the auscultation chambers 16 and 23, 24; and for acoustically isolating each chamber 23 and 24 of the pair of chambers 23, 24 of the second head 22 from the single chamber 16 of the first head 13. More particularly, in the exemplary embodiment depicted herein, switchover mechanism 37, 65-67 has two settings. In its first setting, the switchover mechanism establishes acoustic connections (from 17 to 18 to 52 to 48; and also, from 17 to 18 to 53 to 49) from the single chamber 16 of the first, non-differential auscultation head 13 to both the first and the second acoustic connector portions 46, 47, while acoustically isolating the single chamber 16 of the first auscultation head 13 from each one of the pair of chambers 23, 24 of the second auscultation head 22. In contrast, in its second setting, switchover mechanism 37, 65-67 establishes an acoustic connection (between 25 and 48) from one chamber 23 of the pair of chambers 23, 24 of the second auscultation head 22 to one acoustic connector portion 46 of the two acoustic connector portions 46, 47 and an acoustic connection (between 26 and 49) from the other chamber 24 of the pair of chambers 23, 24 of the second head 22 to the other acoustic connector portion 47 of the two acoustic connector portions 46,47, while acoustically isolating each one of the pair of chambers 23, 24 of the second head 22 from the single chamber 16 of the first auscultation head 13.
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of stethoscope constructions differing from the type discussed above.
While the invention has been illustrated and described as embodied in a stethoscope comprising a double-headed body contact piece having a non-differential auscultation head not provided with a diaphragm and a differential-auscultation head provided with an acoustic diaphragm, it is not intended to be limited to the particular details shown, since various modifications and structural changes may be made without departing in any way from the scope and spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying present knowledge, readily adapt it for various applications without omitting features or aspects that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.