US 3618697 A
Abstract available in
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Description (OCR text may contain errors)
United States Patent  Inventors David Littmann;
} Gustav F. Machlup, both of Belmont, Mass.  Appl. No. 742,404  Filed July 3, 1968  Patented Nov. 9, 1971  Assignee Minnesota Mining and Manufacturing p y Village of Maplewood, Minn. Continuation-impart of application Ser. No. 643,728, June 5, 1967,'now abandoned.
 BINAURAL AND METHOD OF MAKING THE SAME 22 Claims, 34 Drawing Figs.
 U.S. Cl 181/24  Int. Cl. A61b 7/02  Field oISearch 181/24,23; 179/1; 138/177; 11/11  References Cited UNITED STATES PATENTS 8,591 12/1851 Marsh 181/24 1,585,407 5/1926 Morin 181/24 2,261,912 11/1941 Buente 138/177 2,458,884 1/ 1949 Volkmann 128/152 2,498,960 2/1950 Mullin 179/156 3,303,902 2/1967 Knott 181/23 3,437,172 4/1969 Allen 181/24 3,346,069 10/1967 Speelman 181/24 FOREIGN PATENTS 530.297 12/1940 Great Britain. v. l38/D1G. 11
Primary Examiner-Stephen J. Tomsky Attorney-Wolf. Greenfield & Sacks ABSTRACT: A stethoscope method of making a stethoscope binaural from an elongated resilient tubular member preferably having a symmetrical cross section comprising sliding a tubular T-shaped yoke onto the tubular member, then bending and setting the tubular member and T-shaped yoke in a jig into a substantially symmetrical U-shaped having two legs and a bight with one leg and the adjacent portion of the bight lying substantially in one plane and the other leg in its adjacent portion of the bight lying in a second plane intersecting the first at an angle of 150". A hole is formed in the tubular member through the base of the T-shaped yoke and a tubular retaining pin is inserted. A tube is then connected to the tubular pin of the binaural. in a preferred structure of the binaural there is provided a tubular homogenous mass of plastic having a cross-sectional configuration in which the thickness of the tubular wall is greater in a direction normal to the major plane of the stethoscope and in which the binaural is provided with a pair of legs and an interconnecting bight section continuous and integral with one another with the legs resiliently urged toward a normal untensioned position by the characteristics of the plastic material. A generally T-shaped member having a channel in the crossmember of the T and a tubular stem engages the bight of the binaural and provides means for connecting a flexible tube in turn connected to a chest piece.
PATENTEDuuv s I97| 3,618,697
sum 1 OF 6 WWW Y I a? 1 v F5570 M/VENIOR BINAURAL AND METHOD OF MAKING THE SAME The present application is a continuation in part of application Ser. No. 643,728 filed June 5, 1967. now abandoned.
BACKGROUND OF THE INVENTION The present invention relates generally to a binaural construction designed for use with medical stethoscopes.
Medical stethoscopes presently commercially available ordinarily are precision built instruments that are relatively expensive to manufacture. These expensive stethoscopes, however, are not adapted for aseptic procedures presently desired in treatment of most contagious diseases. Although doctors are quite careful to dispose of or sterilize mouth depressors, thermometers and other instruments when treating successive patients, they nevertheless ordinarily fail to use the same careful procedures with their stethoscope. This failure to maintain sterile procedures with respect to a stethoscope if probably due to the fact that this instrument is not disposable and cannot be autoclaved easily. Because of these factors there is a substantial need for a medical stethoscope which is either autoclavable or is relatively inexpensive to manufacture and consequently may be disposed of after a single use. Although there have been efforts to make plastic binaurals which are inexpensive these methods are not satisfactory for several reasons. First, some methods result in binaurals which are not capable of standing up under the considerable abuse to which they are normally subjected. Further, the methods practiced in manufacturing some of these devices are not particularly adapted for mass production purposes. In addition many binaurals made by earlier methods do not fit properly on a wearer's head and have a tendency to torque when worn. This latter problem is a difficulty of considerable importance for it all but eliminates the utility of plastic binaurals of the type described for any purpose other than toys. Torquing is intended to refer to the tendency of a binaural having legs and a bight formed of a single length of plastic tubing to twist about a vertical axis through the center of the bight in opposite directions when worn as a normal binaural.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a disposable binaural design for use in a medical stethoscope which is so inexpensive to manufacture that it may be disposed of after a single use in most ordinary medical practices. It is also an object of the present invention to provide a relatively inexpensive binaural for use as a medical stethoscope which is lightweight, easy to handle, and rugged. A further object of this invention is to provide a binaural for use in a stethoscope made entirely of plastic, and therefore not chilling, in which the bight of the binaural is provided with a reinforcing yoke on its outer surface having a generally T-shaped configuration with the yoke functioning in part to provide controlled flexibility and resiliency. A further object of the present invention is to provide a binaural having ear plugs attached to the ear tube ends of the binaural with the ear tubes formed of a flexible or deformable material designed to be flexed to readily conform with the shape of the wearers ear canal.
It is also an object of the present invention to provide an improved means and method of fabricating in commercial quantities binaurals for stethoscopes from tubing, preferably .of plastic. A further object of the present invention is to provide a method of fabricating binaurals especially designed for stethoscope use which are not likely to torque and which will withstand considerable abuse without leaking or otherwise becoming defective. A still further object of the present invention is to provide an improved binaural construction which is particularly adapted for a variety of uses including and preferably; stethoscopes. One further object of the present inventionis to provide a unique means and method of shaping a binaural for astethoscope to the particular shape found most appropriate for such binaurals. A still further object and advantage of the present invention is to provide a means and method of securely attaching a stem to the bight of a stethoscope binaural.
In one embodiment of the present invention there is provided a stethoscope binaural construction formed of an elongated tubular homogenous mass having a cross-sectional configuration with the cross-sectional diameter in one direction greater than a corresponding cross-sectional diameter normal thereto. The binaural is provided with a pair of legs and an interconnecting bight section continuous and integral with one another. The legs are resiliently maintained in or are urged toward a normal untensioned position against deforming forces at least in part by the characteristics of the mass forming the binaural and, if desired, to some extent by a reinforcing yoke having a T-shape in which the crossmember of the T engages the bight of the binaural.
In a modified form of the invention the legs of the binaural are integrally connected to a resilient yoke which functions in part as a spring member to maintain the legs of the binaural in generally a U-shaped configuration. Further features of the present invention provide improved yoke means for securing the binaural to the stem of the stethoscope.
In the preferred method of the present invention a T-shaped yoke is threaded onto an elongated resilient tubular member. The member is then bent and set into a U-shaped configuration having two legs and a bight with one leg and an adjacent portion of the bight lying substantially in one plane and the other leg and its adjacent portion of the bight lying in a second plane intersecting the first preferably at an angle of substantially 15. A hole is formed in the bight aligned with the stem of the yoke and a retaining pin is then forced through the stem and into the hole. In a modification of the method the U- shaped tubular member may be reformed with its legs in a crossover position. And while in this position a yoke is formed on the bight portion of a resilient material capable of normally retaining the legs in this crossover position. The yoke is formed with two legs molded over the bight and a stem having an opening extending longitudinally through it extending away from the center portion of the bight with the opening in the stem in fluid communication with the opening of the legs.
BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and advantages of the present invention will be more clearly understood when considered in conjunction with the accompanying drawings in which:
FIG. 1 is a partially cross-sectioned elevation of a binaural embodying the invention;
FIG. 2 is a top plan view of the binaural illustrated in FIG. 1;
FIG. 3 is a fragmentary cross-sectional detail of the ear tube and ear plug forming a portion of the invention;
FIG. 4 is an end view of the earplug illustrated in FIG. 3;
FIG. 5 is a cross-sectional view taken substantially along line 5-5 of FIG. 1;
FIG. 6 is a cross-sectional view taken substantially along the line 6-6 of FIG. 1;
FIG. 7 is a cross-sectional view taken substantially along line 77 ofFIG. 6;
FIG. 8 is a cross-sectional view taken along the line 8-8 of FIG. 1;
FIG. 9 is a cross-sectional view of a modification of a binaural illustrated in FIG. 1 taken substantially along a correspond ing line to that illustrated at 8-8 in FIG. 1;
FIG. 10 is a cross-sectional view of a still further modification taken along lines corresponding to line 8-8 of FIG. 1;
FIG. 11 is a plan view of a binaural in fragmentary cross section illustrating a modification of the invention;
FIG. 12 is a plan elevational view of a binaural illustrating a preferred embodiment of the invention;
FIG. 13 is a cross-sectional view taken along line 13-13 of FIG. 12;
FIG. 14 is a cross-sectional view taken along the line 14-14 of FIG. 12;
FIG. 15 is a bottom view of the embodiment illustrated in FIG. 12;
FIG. 16 is a cross-sectional detail of an earplug used in a preferred embodiment of the invention;
FIG. 17 is a bottom view of the earplug shown in FIG. 16;
FIG. 18 is a perspective view of a jig used in making the binaurals of the present invention in accordance with the preferred form of the invention;
FIG. 19 is a component of a yoke used in a modification of the invention;
FIG. 20 is a cross-sectional view taken along the line 20-20 of FIG. 19;
FIG. 21 is a plan view ofthe mating halfof FIG. 19;
FIG. 22 is a cross-sectional detail in an enlarged scale taken along line 22-22 of FIG. 21;
FIG. 23 is a cross-sectional detail taken in an enlarged scale along line 23-23 of FIG. 19;
FIG. 24 is a plan view of one half of mating components used in a modification of the invention and FIGS. 24a to 241 are respectively cross-sectional details taken along the corresponding lines 24a to 24i of FIG. 24 and FIG. 24x is a crosssectional enlargement of the portion of FIG. 24 shown by the dotted circle 24x.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 there is illustrated a binaural comprised of an elongated tubular homogenous mass of plastic material. Preferably the entire binaural construction herein described is made of a synthetic organic plastic material with the plastic material normally being nondeformable but flexible and resilient. A variety of suitable plastics may be used provided they impart the desired physical characteristics to the binaural. A suitable class of plastics includes, for example, plastics in the polypropylene family. The binaural consists primarily of legs 1 and 2 with a continuous and interconnecting bight section 3. The legs 1 and 2 and bight 3 are preferably formed of an extruded polypropylene tubing which is bent by known means on of heat into the shape generally described herein. In this arrangement the free ends of the legs 1 and 2 are bent respectively into ear tubes 4A and 4. The ear tubes 4A and 4 extend generally at a angle from the major plane of the stethoscope. The major plane of the stethoscope is defined for purposes of this disclosure as the plane of a flat surface upon which the stethoscope rests when laid on the surface in the position illustrated in FIG. 1 relevant to the paper of the drawmg.
The tubular cross section of the preferred embodiment is best illustrated in FIG. 8. In this arrangement, as viewed in FIG. 8, the vertical minor axis is shorter than the horizontal major axis with the hole 6 being circular. The greater amounts of mass formed in the wall of the tubular cross section, as illustrated at 7 and 8, extend the entire length of the legs and bight portion on the sides thereof and form integral and homogenous springlike members which normally tension or urge the legs toward a normal position, as illustrated in FIG. 1, against DEFORMING forces. Thus in a normal position the legs 1 and 2 cross each other at 10. When deformed so that the ear tubes 4A and 4 can be fitted into the wearer's ear, the legs 1 and 2 are spread apart to form an open U which, as a consequence of the characteristics of the plastic material used, provides and maintains a force which holds the ear tubes on the wearer's head during normal usage.
In the preferred cross-sectional embodiment illustrated in FIG. 8, a wide variety of cross-sectional configurations and dimensions may be used. A typical cross-sectional arrangement provides an inner dimension in the order of 0. I63 inches with a maximum outer diameter of 0.3 l8 inches and a minimum outer diameter of 0. l 90 inches. The hole or opening 6 through the tubular mass is preferably continuous along its entire length except for an opening 10' centrally located in the bight 3 with this opening directed outwardly in a direction opposite to the direction of the legs 1 and 2. A yoke or T-shaped member 11 having a crossmember l2 and stem 13 is secured to the bight 3 of the binaural. The crossmember 12 is channeled or grooved as best illustrated in FIG. 5, with sidewalls l5 and 16 of the channel extending more than about the bight 3 so as to provide a firm interengaging grip as illustrated in FIG. 5. The ends of this crossmeber are tapered in thickness from the inner ends 17, as illustrated in FIG. 7, to the outer ends 18. The crossmember 12 is preferably flared or curved to conform with the bight 3, as is illustrated in FIGS. 1 and 7. The stem of the yoke or T-shaped member is tubular with the tubular opening 20 extending from the bottom of the stem through the bottom of the cross member 12 and in alignment with the opening 10.
In fabricating this binaural the yoke or T-shaped member 11 is interengaged with the bight 3 before the hole 10' is formed in the bight. After the yoke is secured on the bight, as illustrated in FIG. 1, the hole 10' is drilled through the bight by a drill projecting upwardly through the stem 13.
The yoke may be suitably welded to the binaural tubing by any satisfactory bonding method such as R.F. induction heatmg.
The ear tubes 4A and 4 have secured at their extreme ends plugs 30. Each plug 30, which is best illustrated in FIG. 3, is formed of a resilient deformable thin wall tubular member. This plug may be formed of any suitable material such for example as polyethylene or rubber. The thickness of this tubular member forming the plugs 30 may vary but preferably is in the order of 0.010 to 0.015 inches. The plug is formed with an inner cylindrical segment 31 confonning and frictionally engaging the free end of the ear tube. Continuous with the inner cylindrical segment 31 is an outer frustoconic segment 33 with the segment 33 connected at its narrower end 34 to the outermost end of the inner cylindrical segment. The other end 35 of the frustoconic segment is free and spaced from the tubular segment. The tapered or frustoconic shape 35 is easily deformed to conform with the wearer's ears without any discomfort.
The binaural legs 1 and 2 and bight 3 may be extruded in a variety of shapes. Such shapes are illustrated in FIGS. 9 and 10. Thus, for example, in FIG. 9 the cross-sectional shape of FIG. 8 may be modified by providing side bulges 41 and 42 which are presumed to function much in the fashion as a spring to normally maintain the binaural in the shape of FIG. I when not under stress. FIG. 10 illustrates a further modification in which rectangular shapes are used to maintain a greater mass in one cross-sectional direction than another to effect a springlike action on the binaural. In this arrangement there is a greater mass on sides 43 and 44 which are also at the sides of the binaural.
Referring to FIG. 11 there is illustrated an arrangement in which the binaural 40 is formed with legs 41 and 42 integrally connected by a bight portion 43. These legs 41 and 42 and the integral bight 43 may be formed of the same material and with the same cross-sectional configuration as the embodiment illustrated in FIG. 1. The free ends, the legs 41 and 42 extend preferably in planes which lie in a 15 angle with respect to the major plane in the stethoscope. The ends of the legs 41 and 42 are provided with ear plugs 44 and 45 which may be similar to those hereafter or previously described. The integral legs 41, 42 and bight 43 are preferably shaped and set in the position illustrated in FIG. 11. A yoke generally illustrated at 45 is then formed about the bight 43 and adjacent ends of the legs 41 and 42. The yoke 45 is integrally formed with legs 46 and 47 interconnected by a bight portion 48. A stem 49 extends symmetrically downwardly from the bight 48. An opening 48A through the legs 46, 47 and bight 48 is preferably shaped and dimensioned to conform with and is engaged by the outer dimensions of the legs 41, 42 and bight 43. The opening through these legs 46, 47 and bight 48 freely communicates with the opening 488 through the stem 49. The yoke 45 is positioned snugly over the bight 43 and adjacent portions of legs 41 and 42 with an opening 50 in the bight 43 aligned with the opening in stem 49 to provide free fluid communication between the legs 41, 42 and internal portion of the stem 49.
The wall thickness of the legs 46 and 47 preferably should taper from a thickest portion adjacent the stem 49 to the thinnest portion at the free ends of legs 46 and 47. A gradual tapering 'of a thickness from 0.050 to 0.010 inches is satisfactory. This yoke 45 may be made of a variety of materials including for example,-the same type of materials of which the legs 41, 42 are formed. By tapering the legs 46 and 47 of the yoke as indicated, a greater spring action may be effected on the legs 41 and 42.
Referring now to FIGS. 12-17 inclusive there is illustrated a preferred embodiment of the present invention. In this arrangement the binaural is preferably formed with an elongated tubular member 51 shape to provide legs 52 and 53 integrally connected by a bight 54. The tubular member 51 is formed, preferably, with a wall having a nonuniform thickness. In the preferred embodiment the wall thickness which is illustrated in FIG. 14 has a major axis 56 and a minor axis 57 extending at right angles to one another. The major axis preferably should be in the order of magnitude of 50 to 100 percent greater than the minor axis and in a preferred embodiment the major axis 56 should have a length of 0.320 inches and the minor axis 0.190 inches. The hole or aperture 58 that extends longitudinally through the tubular member 51 is preferably circular in cross section and has a diameter in the order of magnitude of about 30 to 40 percent ofthe major axis. In the specific embodiment the diameter 58 is in the order of magnitude of 0.125 inches.
The ear tubes 52 and 53 extend generally at a angle from the major plane of the stethoscope. The major plane of the stethoscope is defined for purposes of FIG. 12 as a plane of a flat surface upon which the stethoscope rests when it is laid on the surface with the side 60 (FIG. 15) touching the surface. In this position the legs 52 and 53 will touch the surface in the areas generally illustrated at 61 and the bight portion 54 as well as the free ends 63 of the legs 52 and 53 will be remote from the surface. The main axis 56 is flared outwardly in opposing portions of the legs 52 and 53 as viewed in FIG. 12 looking downwardly at the binaural when it is resting on its major plane.
The yoke 65 is preferably formed of an injection molded relatively rigid plastic having sufficient structural rigidity to withstand substantial abuse and may be made of a wide variety of materials including for example, polypropylene plastic. The yoke 65 is formed with relatively short legs 66 and 67 connected integrally to a stem 68 with the legs 66 and 67 having a passage in fluid communication with a passage through the stem 68. The cross-sectional configuration of the passage through the legs 66 and 67 conforms to the outer cross-sectional configuration of the bight 54. The bight 54 snugly fits within and extends through the legs 66 and 67. An opening in the bottom of the bight 54 connects the interior of the legs 52 and 53 with the passage through the stem 6. A metal pin 70 is inserted in the stem 68 and extends into the bight 54. This pin 70 is formed with a tubular body 71 that is opened at either end. One end of the tubular body 71 is formed with an outwardly flared lip 72. This end of the body 71 is also formed with a longitudinally extending slot 73 which extends preferably at least one-third its length and in any event a distance sufiicient to permit portions of the lip 72 on opposite sides of the slot 73 to be resiliently compressed toward one another when the pin 70 is inserted within the yoke 65. The lip 72 is positioned within the bight 54 and has a shoulder 75 that engages the inner surface of the bight 54 thereby securely maintaining the pin 70 in engagement with the bight 54. The pin 70 is also provided with a peripheral outwardly extending flange 76 that is spaced fromthe lip 72 a distance sutficient to snugly engage the lower edge 77 of the stem 68 when the lip 72 is engaged with the inner surface of the bight 54. The portion of the tubular member 71 which projects from the flange 76 beyond stem 68 is designed to engage a flexible tube 79. This flexible tube 79 which may be of any convenient length, is connected at its other end in a conventional fashion to its chest piece. In this arrangement the inner diameter of the pin 70 is preferably in an order of magnitude about twice the thickness of the wall forming the tubular member 71.
The ear tips which are preferably used in the embodiment of FIG. 12 are best illustrated in FIGS. 16 and 17. In this arrangement the ear tip is fonned with an annular wall 80 about a passage 81. The passage 81 has a first section 81a which is oval in cross-sectional configuration and is dimensioned to snugly fit about the ends of the ends of the legs 52 and 53 in frictional engagement. This section 810 has a length which is preferably more than half the length of the ear tip. An ad jacent section 81b is preferably circular in cross section and forms a shoulder 81c with section 81a that is adapted to engage the extreme end of the legs 52 and 53. A section 81d continuous with section 81b may be flared outwardly as illustrated in FIG. 16. The outer surface 83 of the ear tip should be shaped to conform with the outer portion of the wearer's ear canal.
The stethoscope illustrated in the preferred embodiment of FIG. 12 may be fabricated utilizing a jig of the type illustrated in FIG. 18. In the fabrication of this stethoscope a length of tubing preferably extruded of polypropylene and having the cross-sectional configuration illustrated in FIG. 14, is cut to a selected length as for example, 17 It inches. This tubing is then heated to a temperature sutficient to render it workable.
lf'the material of which the tubing is fonned is polypropylene,
it may be preheated to a temperature of approximately 200 F. At this temperature the tubing is softened to the extent that permits it to be flexed or bent but does not close the longitudinal hole extending through it. After the tubing has been cut to a satisfactory length a yoke 65 is threaded onto this straight tubing and is centrally located wit respect to it. The yoke is threaded onto the tubing so that its stem 68 extends perpendicularly from the major axis 56 of the tubing.
The heated tubing is then placed in a jig of the type illustrated in FIG. 18. This jig is preferably formed of metal and has two major faces and 91 lying in planes that diverge one from the other at an angle of 150, channels 92, 93 and 94 are formed in the surfaces 90 and 91. The channels 92 and 94 are formed respectively in the surfaces 90 and 91. These channels 92 and 94 are mirror images of each and are symmetrically arranged with respect to channel 93. Channel 93 extends longitudinally of the jig shown in FIG. 18 and defines the adjacent edges of the surfaces 90 and 91. The channels 92 and 94 have a cross-sectiona1 configuration along their major lengths such as to receive the tubing with the major axis 56 of the tubing in channel 92 perpendicular to surface 90 and the major axis 56 in tube in channel 94 perpendicular to surface 91. An enlarged portion of the channels 92, 94 is formed at their juncture as indicated at 98 with this enlarged portion designed to receive the yoke 65 which has previously been threaded onto the tubing. The enlargement 98 is formed with segments 99, 100 and 101 designed respectively to receive the legs 67, 66 and stem 68 in a relatively snug fit. The channel 93 opens to end 102 of the jig and is designed to permit access through the stem 68 to the bight 54 of the tubing when it is positioned within the jig.-
The tubing is inserted into the channels of the jig of FIG. 18 with one end of the tubing positioned at end 96 of channel 92 and the other end of the tubing positioned at end 97 of channel 94. The yoke 65 is positioned in the enlarged portion 98 with the stem 68 lying longitudinally in section 101. In order to position the tubing within these channels of the jig the tubing is heated to approximately 200 F. At this temperature the tubing will sofien sufficiently to permit it to work and bent into the configuration of the channels 92 and 94. After the tubing and yoke have been positioned in the jig the tubing is subjected to an increased amount of heat sufficient to set the tubing in the position defined by the channels 92 and 94. If the material of the tubing is propylene the material should be heated to 300 F. and maintained at this temperature for about 5 minutes. The temperature however, should not be raised to a point that will cause the material to flow and thereby deform the tubing. The temperature should also be sufficiently high to assure setting of the material in the position to which it is initially held by the channels 92, 94.
After the tubing has been set in the position in which it is held by the jig, it is cooled. A hole is then drilled in the tubing through the opening in the stem 68 of the yoke 65 so as to complete a fluid connection between the interior of the arms 52, 53 and the passage in the stem 68.
While the tubing and yoke are still in the jig, the pin 70 is inserted into the stem 68. This pin 70 is forced axially into the opening of the stem 68. When the pin 70 is forced into the stem 68 the leading end of the pin will be compressed as the slot 73 closes thus permitting the lips 72 to pass through the opening of the stem. The pin is forced into the stem 68 a sufficient distance as to permit the leading end of the pin to pass though the hole that was drilled in the tubing and into the interior of the tubing so that the lips 72 will engage the inner surface of the tubing. The flange 76 precisely controls the depth to which the pin may be inserted. Afier the pin has been inserted the partially assembled binaural is removed from the jig and is finished into a stethoscope or comparable instrument by attachment of the ear tips of the type illustrated in FIG. 16 to the free ends of the legs 52 and 53. The tubing 79 is frictionally engaged with the projecting end of the pin 71 and may have desired it be secured by a suitable means such for example by cement. The other end of the tubing 79 may be connected to a stethoscope chest piece or other instrument.
The stethoscope binaural illustrated in FIG. 12 is formed with the free ends of its legs 52 and 53 close to or substantially touching each other when in a normal untensioned position. It has been found that by proper selection of the material of which the tubing is formed, this shape provides adequate tension when the free ends are separated for placement in the wearer's ears. If desired, however, the techniques herein illustrated may be utilized to form a stethoscope in which the legs 52 and 53 crossover.
The present invention also contemplates fabricating a binaural with a yoke that is attached after the binaural has been shaped in the manner as previously described. In such an arrangement the yoke is formed of mating pairs which are attached to the bight of the binaural tube after the tube has been shaped. The yoke may comprise a male 110 and a female half 112 shown respectively in FIGS. 19 and 21. These halves each provide arcuately curved legs 113 and 114 having cross-sectional configurations which are semicircular. The opposite longitudinal edges of the leg 113 are provided with a longitudinally extending bead 115 illustrated in large form in FIG. 23. The opposite longitudinal edges of the legs 114 are formed with a female channel or recess 116 that is designed to mate with the bead 115. The two halves 110 and 112 may be snapped over the bight 54 of the tubular member and may be suitably secured together by cement or other means. A stem or tube 118 projects outwardly from and secured at one end within an opening formed by cutaway portions in the opposite legs I13 and 114.
A still further modification of the present invention is illustrated in FIG. 24. In this arrangement the binaural is formed in a two-piece construction with one of the pieces illustrated in FIG. 24. The piece not shown is a mating piece designed to mate with the piece shown in FIG. 24 along its entire length to form a complete binaural. The piece shown in FIG. 24 has leg segments 154 and 155 connected by a bight segment 156 car tip segments I57 and 158 are integrally formed at the ends of the segments I54 and 155 respectively. A stem segment 160 is connected to and integrally formed with bight section 156. The cross-sectional configurations of the various sections illustrated in FIG. 24 are shown respectively in FIGS. 24a to 241. It will be noted that the cross-sectional configurations illustrated in FIGS. 24a, b, c, d, e all have projecting beads or ribs 170 along one or both sides as illustrated. When a mating half is placed in facing relation and the two mating halves are subject to a conventional ultrasonic-sealing process, the beads 170 will fuse into the opposite surface and provide a permanent interengagement. The beads are formed only on onehalf of the edges of the component illustrated in FIG. 24 leaving smooth the leg segment I55 and one half of the stem segment I60 thus providing a smooth surface against which the bead 170 may rest when they are placed in facing engagement for ultrasonic sealing.
After the two halves are joined as described, the legs which are formed from the leg segments 154, 155 are bent so that they lie in planes that intersect at an angle of 150". This may be effected by heating the members which have been joined ultrasonically to a temperature sufficient to permit the binaural to be worked but not high enough to cause deformation. And if polypropylene is used as the material, a temperature in the order of 300 F. should be satisfactory.
The embodiment illustrated in FIG. 24 may also be made in several additional segments wherein the leg segments I54 and 155 are formed separately from and independently of the bight. The bight in turn may be integrally formed as a yoke adapted to receive the assembled legs 154 and 155.
In a further modification of this invention a tubing is formed and shaped in a jig of the type described in FIG. 18 except that no yoke is attached to the tubing before its shaping. Thereafter a pin is inserted through the wall of the tubing extending downwardly from the bight. The tube is then dipped in a hot dip of a suitable plastic whereby the bight portion of the tube and the inserted pin are coated with the molten plastic to form an integral yoke. The pin is thereafter removed from the stem of the yoke. yoke. A suitable material for such dip may comprise the material which hardens upon cooling into a flexible and preferably resilient material. Suitable rubber latex and resins may be used.
What is claimed is:
l. A binaural construction formed of an elongated tubular homogenous plastic mass having a cross-sectional configuration wherein one cross-sectional axis is greater than a corresponding cross-sectional axis normal thereto, said binaural having a pair of rigid legs and an interconnecting bight section continuous and integral with said legs, means for resiliently tensioning said legs toward a normal untensioned position against deforming forces with said last-mentioned means formed at least in part by the characteristics of said mass, a tubular stem, and means securing said stem to said bight with the passages defined by said tubular mass and said tubular stem in fluid communication, said securing means including a tubular body with one wall defining said tubular body coaxial with and engaging an annular surface at one end of said tubular stem, said tubular body having an end projecting from said one end of said tubular stem into engagement with said bight with a portion of said one end of said tubular body extending angularly from the axis thereof into locking relation with said bight.
2. A binaural construction formed of an elongated tubular homogenous plastic mass having a cross-sectional configuration wherein one cross-sectional axis is greater than a corresponding cross-sectional axis normal thereto, said binaural having a pair of rigid legs and an interconnecting bight section continuous and integral with said legs, means for resiliently tensioning said legs toward a normal untensioned position against deforming forces with said last mentioned means at least in part by the characteristics of said mass, wherein a wall formed by said tubular cross section is nonuniform in thickness, and at least in part defines said means for resiliently tensioning said legs, a tubular stem, and means securing said stem to said bight with the passages defined by said tubular mass and said tubular stem in fluid communication.
3. A binaural as set forth in claim 2 wherein said wall is continuous along its length except for a portion in said bight wherein a hole extends therethrough in a direction away from the direction of said legs.
4. A binaural set forth in claim 3 wherein the thicker portions of said walls extend in directions substantially normal to a plane passing through both of said legs of said binaural.
5. A binaural as set forth in claim 4 wherein the ear tube ends of said binaurals extend at an angle of substantially 15 from a major plane, said major plane being defined as a plane of a flat surface upon which said binaural rests when laid upon said surface with both legs in contact therewith.
6. A binaural as set forth in claim wherein said means securing said stem includes, a yoke of generally a T-shaped configuration with the crossmember of the T channelled to conform and engage said bight over said hole, and the stem of said T-shaped configuration is tubular.
7. A binaural as set forth in claim 6 wherein the wall thickness of said crossmember tapers from thick to thin in a direction away from said stem.
8. A binaural construction formed of a pair of nonparallel, plastic legs interconnected by a plastic bight and a flexible tube operatively engaged with said bight, said legs and bight comprising an elongated, integral, continuous, tubular, homogenous, rigid mass having a nonuniform, cross-sectional shape and a composition resiliently resistive to deforming forces, said flexible tube formed of an elongated, flexible, tubular member with means interconnecting the interior of said flexible tube and bight, and one of said legs and an adjacent portion of said bight lying substantially in a plane intersecting at an angle a second plane with said other leg and portion of said bight adjacent thereto lying substantially in said second plane.
9. A binaural construction as set forth in claim 8 wherein said means interconnecting said flexible tube and bight is fonned of material more rigid than said flexible tube and bight.
10. A binaural comprising a U-shaped, tubular plastic member an a flexible tube extending from and in fluid communication with said U-shaped member, and said U-shaped tubular member having a bight portion formed of a rigid, homogeneous mass having resilient characteristics exhibiting springlike action such as to resist deflection of the legs of said U-shape from a selected nonparallel position by deflecting forces, said tubular member having at least one surface which is noncircular in cross section with two orthogonally related nonequal dimensions, the larger of the two dimensions lying in a planesubstantially normal to a plane containing the legs of said U-shaped member, whereby said binaural may be secured with said legs exerting pressure on opposite sides of a user's head, and means connecting said flexible tube to said U- shaped tubular member.
ll. A binaural as set forth in claim 10 wherein said tubular member is formed of an integral, continuous single piece of material integrally and continuously formed.
12. A binaural as set forth in claim 11 wherein said bight portion and legs are formed of a continuous single member having a tubular passage with a noncircular cross section.
13. A binaural as set forth in claim 10 wherein said legs have an outer surface with a noncircular cross section.
14. A binaural as set forth in claim 10 wherein said bight and said legs are formed of a continuous length of plastic material having a noncircular cross section, and said means connecting said flexible tube to said U-shaped tubular member comprises a yoke having two yoke legs and a yoke stem with said yoke legs interengaging said, tubular member and said yoke stem interengaging said flexible tube 15. A binaural as set forth in claim 14 wherein said yoke is formed of a material of greater rigidity and resilience than said tubular member.
16. A binaural as set forth in claim 10 wherein the outer surface of said tubularmember is oval in cross-sectional configuration.
17. A binaural as set forth in claim 16 having car tips coaxially secured to the ends of said legs of said tubular member and having an opening in facing engagement with the ends of said legs, said openings of said car tips having an oval cross section.
18. A binaural as set forth in claim 10 wherein said means connecting said flexible tube to said U-shaped tubular member comprises a tubular insert having one end engaging said flexible tube and the other end extending into said bight portion.
19. A binaural as set forth in claim 18 wherein said other end of said tubular insert is formed with an outwardly flared lip eng g the inner wall of said bight.
20. manure] as set forth in claim 19 wherein said insert is formed of metal and said insert extends into and is coaxial with said stem.
21. A binaural construction formed of a pair of nonparallel, plastic legs interconnected by a plastic bight and a tubular stem extending angularly from said bight, said legs and bight comprising an elongated, integral, continuous, tubular, homogeneous, rigid mass having a nonuniform, cross-see tional shape and a composition resiliently resistive to deforming forces, said stem fonned of an elongated, flexible, tubular member with means interconnecting the interior of said stem and bight, said tubular member having an outer surface that is oval in cross-sectional configuration and an inner surface that is circular in cross-sectional configuration, and one of said legs and an adjacent portion of said bight lying substantially in a plane intersecting at an angle a second plane with said other leg and portion of said bight adjacent thereto lying substantially in said second plane.
22. A binaural as set forth in claim 21 wherein the major axis of said oval configuration extends angularly from the major plane of said binaural.