US 3712409 A
In a stethoscope of the type having a body with a pair of opposite cavities one of which is covered by a diaphragm, a switching pin is provided at right angle to the stethoscope axis which co-operates with a pair of coupling-out stubs. Both the stethoscope body and the switching pin are provided with passages through which one or the other of the cavities will be connected with the pair of coupling-out stubs. Thus, sounds or noises of higher frequency (treble) can be observed without absorption by deep sounds if the cavity with the diaphragm is placed on the observation surface since, then, deep sounds or noises of lower frequency are filtered out by the diaphragm. In the other position of the switching pin, the uncovered cavity of the body communicates with the pair of coupling-out stubs in which case sounds or noises of lower frequency (bass) can be observed. Obviously, in this case no filtering is necessary because deep sounds or noises absorb those of higher frequencies.
Description (OCR text may contain errors)
United States Patent [191 Kizakisz et a1.
 STETHOSCOPE  lnventorszlliasz Kizakisz, Budapest XVII; Vilmos Horvath, Budapest XV,
[ 1 Jan. 23, 1973 Primary Examiner-Stephen J. Tomsky Alt0rneyYoung & Thompson  ABSTRACT In a stethoscope of the type having a body with a pair of opposite cavities one of which is covered by a diaphragm, a switching pin is provided at right angle to the stethoscope axis which cooperates with a pair of coupling-out stubs. Both the stethoscope body and the switching pin are provided with passages through which one or the other of the cavities will be connected with the pair of coupling-out stubs. Thus, sounds or noises of higher frequency (treble) can be observed without absorption by deep sounds if the cavity with the diaphragm is placed on the observation surface since, then, deep sounds or noises of lower frequency are filtered out by the diaphragm. 1n the other position of the switching pin, the uncovered cavity of the body communicates with the pair of coupling-out stubs in which case sounds or noises of lower frequency (bass) can be observed. Obviously, in this case no filtering is necessary because deep sounds or noises absorb those of higher frequencies.
10 Claims, 11 Drawing Figures "J as PAIENIEDJAN23 1975 3,712 409 sum 2 or 2 STETIIOSCOPE This invention relates to stethoscopes or sensors which are used for observing sounds or noises of the heart, the lungs and the veins and which transmit such sounds or noises from an observed portion of a patients body into a yieldable tube and, there through, into the ear of an observer.
The known stethoscopes are suitable for observing of sound of noises within a relatively narrow range only such as the heart or the lungs or the veins and, therefore, their use is limited to the medical treatment of the respective part of the body. In order to eliminate such deficiency it has been suggested to employ stethoscopes having a pair of concave surfaces or cavities which may be employed in the whole frequency range of medical auscultation. The known suggestion is based on the acoustic phenomenon of high frequency sounds being suppressed by low frequency ones. Therefore, one of the concave surfaces or cavities of a stethoscope is-according to the known suggestioncovered by a diaphragm the purpose of which is an amplified transmission of higher frequencies-higher sounds-without distortion. Obviously, the diaphragm can be selected so as to filter out low frequency sounds. The other concave surface or cavity is open and is destined to transmit low frequency-deeper-sounds where the danger of absorption of high frequency sounds is of no significance any more. However, due to the necessity of switching over from one cavity to the other coupling-out of the sounds transmitted by the stethoscope has hitherto been effected by so-called single lead-outs which, at the same time, serve for switching over means. The single lead-outs have then been complemented by flexible Y-tubes by means of which the vibrations coupled out of the stethoscope have been subdivided and lead into the ears of an observer separately. A deficiency of such expedient, however, consists in the obligatory use of a Y-tube because it means a considerable, resistance against propagation of vibrations whereby stethoscope sensitivity has significantly' been decreased.
The main object of the present invention is to obviate the aforesaid deficiencies and the provision of a stethoscope which has, besides'double lead-outs, a pair of cavities and, thus, a required sensitivity in the whole frequency range of observation. .The basic idea of the invention is that such stethoscopes may be obtained if separate component parts are provided for couplingout and controlling respectively, in contrast to the known devices of a similar destination, as described above. For that purpose in addition to a pair of coupling-out stubs also a switching pin for alternately connecting the coupling-out stubs with the cavities is employed. This is rendered possible by that the stethoscope comprises, in a manner known per se, a shield in addition to its body. It has been found that both the pair of stubs and a hole guiding the switching pin can be provided for without intermingling with one another.
Summarily, the invention is concerned with a stethoscope comprising, in a manner known per se, a body, an open cavity in said body, a hollow shield forming an extension of the-body in a direction opposite to said open cavity, a diaphragm closing the cavity in said shield, and an axial hole connecting both cavities through said body. In accordance with the main feature of the invention, the body comprises a pair of couplingout stubs and a switching pin at right angle to its axis, both coupling-out stubs being connected through the switching pin with said axial hole while the switching pin is provided with passages for connecting said cavities alternately with one of the coupling-out stubs in extreme positions of the switching pin.
With an arrangement according to the invention, it is possible to accommodate the coupling-out stubs and the switching pin in the body of the stethoscope without particular machining difficulties and in consideration of strength characteristics. Moreover, by means of a simple axial displacement of the switching pin, it is possible to determine which of both cavities of the stethoscope be connected with the coupling-out stubs without the necessity to perform any assembly or rearrangement work. The pair of coupling-out stubs may have a twin tube connected directly to them through which vibrations caused by sounds or noises picked up by the stethoscope will be transmitted to their destination place without any attenuation due to subdivision.
Further details of the present invention will be described by taking reference to the accompanying drawings which show, by way of example, an embodiment of the stethoscope according to the invention and in which:
FIG. 1 is a side elevational view partly in section.
FIGS. la and 1b show each a detail on a relatively larger scale.
FIG. 2 illustrates a sectional view taken along the line II-Il of FIG. 1.
. FIG. 3 represents a longitudinal sectional view of a detail.
FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 3.
FIG. 5 represents a cross-sectional view taken along the line V--V of FIG. 3. I
FIGS. 6 to 9 are cross-sectional views showing various operational positions.
In the drawing, reference numeral 10 designates the body of a stethoscope according to the invention comprising an open cavity 12. Opposite to this open cavity 12, that is to the left in FIG. 1, a hollow shield 14 is provided which forms an extension of body 10 and the cavity of which is referred to by reference character 16. The cavity 16 in shield 14 is closed by a diaphragm 18. Both cavities l2 and 16 are connected with one another through the body 10 by a hole 22 arranged in axial direction 20.
In compliance with the main feature of the invention, the body 10 comprises, at right angle to its axis 20, and in radial direction, a pair of coupling-out stubs 24 and 26, and a switching pin 28. The axes of the couplingout stubs 24 and 26 as well as of the switching pin 28 are referred to by reference numerals 30, 32 and 34, respectively. Both coupling-out stubs 24 and 26 are connected through the switching pin 28 with an axial bore 22 while the switching pin 28 comprises passages which connect the cavities l2 and 16 alternately with one of the coupling-out stubs 24 and 26 as will be described hereinafter in closer details.
With the represented embodiment, the switching pin 28 is provided with a pair of radial blind holes 36 and 38 which open in mutually opposite directions as will the right and blind hole 38 opens to the left as regards the' drawing. Both blind holes 36 and 38 are, in addition, mutually spaced along the axis 34 of switching pin 28. Moreover, they are connected with one another by means of an axial groove 40 which opens towards the coupling-out stubs 24 and 26, as goes forth particularly from FIG. 2. It will be seen that the blind holes 36 and 38 are confined by simple cylindrical surfaces which open into the groove 40 and may be easily machined in the switching pin 28.
Furthe'rmore,with the represented exemplified embodiment, the switching pin 28 is guided in a hole 42 which is formed in the body of the stethoscope between the cavities 12 and 16. The switching pin 28 may be displaced in the hole 42 between a pair of extreme positions each of which is illustrated in FIGS. 6 and 7 or 8 and 9, respectively.
Preferably, displacements of the switching pin 28 between the aforesaid-extreme positions will preferably be braked since, otherwise, the switching pin 28 may glide from one extreme position into the other one unintentionally. With the represented embodiment, suchbraking is warranted by loading the switching pin 28 by a ball 46 accommodated in a blind hole 44 and biased by a spring 48 so that the ball 46 engages an axial nest 50 which is provided at the opposite side of the switching pin 28 as regards the axial groove 40 as goesforth particularly from FIG. 3. 1
With the represented embodiment, there are assembly holes 52 and 54 between the nest 50 and the blind holes 36 and 38, respectively, illustrated particularly in FIGS. 4 and 5. The assembly holes 52 and 54 permit to push back the spring loaded ball 46 into blind hole 44 in the body 10 whereupon the switching pin'28 may be removed from its hole 42. On the other hand, when the switching pin 28 is pushed into hole 42 and is displaced inwardly while the ball 46 is pushed back against biasing spring 48, the ball 46 will gradually jump into nest 50 whereby the switching pin 28 is, in addition to being braked, also secured against falling out.
It will be seenthat the blind hole 44 which accommodates the spring 48 biasing the ball 46 is coaxially arranged with one of the coupling-out stubs 24 and 26, more particularly, in the instant case with the axis 32 of the coupling-out stub 26. Such arrangement permits that the hole for receiving the coupling-out stub 28 and the hole 44 for receiving the ball 46 may be manufactured by employing one and the same setting for both operations. The coupling-out stubs 24 and 26 are fixed in the body 10 by means of tight fit. This most simple connection is permitted by the essentially radial arrangement according to the invention of the coupling-out stubs, displacement of which may be dispensed with for the purpose of switching over performed now by the switching pin 28. Nevertheless, the coupling-out stubs 24 and 26 might be fixed, e.g., by means of threaded connection as well if necessary.
Furthermore, as goes forth from FIGS. 1 and 2, the shield 14 comprising the cavity 16 is of circular shape and the cavity 16 itself has a spherical surface. The diaphragm 18 covering the cavity 16' of the shield 14 is held down by a ring 56 threadedly engaging shield 14. The open cavity 12 has a yieldable funnel 58 connected to it which forms with its inner surface an extension of the cavity 12. According to test results, such stethoscope results in excellent acoustic conditions. At the same time, it permits to employ recent manufacturing methods (cold working) without cutting operations.
The yieldable funnel 58 is connected with a peripheral groove 60 of the body 10 and is supported by cylindrical surfaces 62 and 64 at both sides of groove 60, and by a shoulder 66 of the body 10. Such details are illustrated in FIG. In on a relatively larger scale. The advantage of such arrangement consists in the simple geometrical form of the fixing surfaces and their easy manufacturing ability due to such forms.
It will be seen from FIG. 1 that the diaphragm 18 closing the cavity 16 of the shield 14 and its support surface 14a have a ring 68 of circular cross-section inserted between them the details of which are shownin FIG. 1b on a relatively larger scale. The diaphragm 18 is constantly tightened thereby. A further advantage consists in improving the acoustic conditions of the device as has been proved by test results.
Preferably, the ring 68 of circular cross-sectional area will protrudefrom the support surface 14a even in assembled position since, thereby, also the diaphragm 18 will protrude from the front surface of the ring 56 so that'it can be placed along its whole surface on a patients body the advantage of which is obvious. For this purpose, the diaphragm 18 is provided with a bent down brim 18a.
The coupling-out stubs 24 and 26 may have a yieldable twin pipe 70 connected to them the bifurcated extremities of which are pushed each on one coupling-out stub 24 and 26 as shown in FIG. 2. As has been mentioned, the yieldable twin pipe 70 as such serves for considerably decreasing the resistance against acoustic waves whereby the sensitivity of the stethoscope becomes significantly increased. From a manufacturing point of view, the pipe does not entail any difficulties while its yieldability is big enough not to impede medical examination. a
coupling-out stubs 24 and 26 whereby a complete stethoscope is obtained and rendered serviceable.
If higher frequency noises, viz. high'soundsare to be observed, the stethoscope is placed with its cavity 16 covered by the diaphragm 18 on the patients body while the switching pin 28 is displaced into its position shown in FIGS. 1 and 2 where the blind hole 38 occupies its position in the axis 20 of the stethoscope. Then, the cavity 16 is connected through hole 22, blind hole 38 and groove 40 with the coupling-out stubs 26 so that sound vibrations picked up by the diaphragm 18 will be transmitted into twin tube 70. Such position is shown in FIGS. 6 and 7 where switching pin 28 and holes 36, 38 and 40 in the body 10 are illustrated on a relatively larger scale.
If sounds 'of lower frequency, that is of deeper range are to be observed, absorption phenomena may be disregarded and therefore filtering would be unnecessary. Thus, the stethoscope is placed on the patients body with its open cavity 12 without diaphragm. At the same time, however, switching pin 28 is axially displaced in the direction of arrow 74 (upwards in FIG. 1)
In operation, the twin pipe 70 is connected to the whereby blind hole 36 coincides with axis which means that cavity 12 is connected with the couplingout stubs 24 and 26 through hole 22, blind hole 36 and groove 40. Such position is illustrated in FIGS. 8 and 9.
In order to replace diaphragm 18 it is only necessary to screw off ring 56. Ring 68 may be replaced in a similar manner.
If the switching pin 28 has to be removed from the stethoscope, it is caused to occupy its position shown in FIG. 2 where the ball 46 is pushed by means of a needle-like instrument through the coupling-out stub 26, groove 40, blind hole 38 and hole 54 (FIG. 5) against spring 48 into blind hole 44. Then, a slight axial dis placement (downwards in FIG. 2 which is the direction of arrow 76 opposite to the direction of arrow 74) already prevents that removal of switching pin 28 be locked by the ball 46 which would engage nest 50.
A replacement of funnel 58 may be obtained by means of simple deformation in a manner known per se.
It will be clear from what has been said above that manufacturing and operation or use of double cavity or double funnel stethoscopes are rendered extraordinarily simple as regards both technology and operation by simplifying the function of the coupling-out stubs and by employing a switching pin independent therefrom. Thereby, the personal strength of the observer is husbanded. In addition, the duration of examination will become shorter which is a considerable advantage as regards the patient.
What is claimed is:
1. A stethoscope comprising a body having a pair of cavities therein that open outwardly in opposite directions, one of said cavities being covered by a diaphragm, there being an axial hole through said body interconnecting said cavities, means on said body for connecting stethoscope tubing to said body in a direction transverse to said hole, a switching pin mounted for sliding movement lengthwise of itself in said body, said pin having passage means therein such that in one position of said pin one of said cavities communicates through said hole and through said passage means with said connecting means, while in another position of said pin the other of said cavities communicates through said hole and through said passage means with said connecting means.
2. A stethoscope as claimed in claim 1, said passage means including a pair of radially extending blind holes in said pin that are spaced apart lengthwise of said pin and that open through said pin in opposite directions for selective communication with one of said cavities depending on the position of said pin, and a groove extending lengthwise of said pin and interconnecting said blind holes and opening toward said connecting means.
3. A stethoscope as claimed in claim 2, said pin having a second groove therein opposite and parallel to the first-mentioned groove, and a spring-biased ball disposed in said second groove to brake the sliding movement of said pin.
4. A stethoscope as claimed in claim 3, there being assembly holes extending between said blind holes and said second groove.
5. A stethoscope as claimed in claim 3, the biasing spring of said ball being disposed in a blind hole in said body, said blind hole being coaxial with said connecting ii f li stethoscope as claimed in claim 1, said connecting means comprising a short nozzle force-fitted in said body.
7. A stethoscope as claimed in claim 1, said cavities being part spherical, a ring screw-threadedly connected to the margins of said one cavity releasably to secure said diaphragm thereon, the other cavity being rimmed with an annular yieldable member which forms an extension of the side walls of said other cavity.
8. A stethoscope as claimed in claim 7, said annular yieldable member having an internal flange that is releasably retained in an annular outwardly opening groove in said body surrounding said other cavity, said yieldable member engaging cylindrical surfaces at both sides of said groove and engaging an annular abutment shoulder on said body.
9. A stethoscope as claimed in claim 7, and a second ring of circular cross section disposed between said diaphragm and the rim of said one cavity, said second ring protruding from said rim, said diaphragm being bent down about said ring against said rim and held thereagainst by the first-mentioned ring.
10. A stethoscope as claimed in claim 1, and a flexible tube releasably connected to said connecting means.
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