US3614991A

US3614991A - Stethoscope chestpiece

Info

Publication number: US3614991A
Application number: US719927A
Authority: US
Inventors: Gustav F Machlup; David Littmann
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1968-04-09
Filing date: 1968-04-09
Publication date: 1971-10-26
Anticipated expiration: 1988-10-26
Also published as: GB1271093A; DE1916826B2; BR6802949D0; DE1916826A1; FR2005863A1

Abstract

A STETHOSCOPE CHESTPIECE CONSTRUCTION INCLUDING A DIAPHRAGM FORMED OF A FLAT THIN FLEXIBLE RESILIENT BODY HAVING AN INTEGRAL ANGULARLY FLARED LIP ABOUT ITS PERIPHERY ADAPTED TO SNAP OVER AND ENGAGE A COMPLEMENTARY SHOULDER IN THE BODY OF THE STETHOSCOPE HEAD. AN ANNULAR BEVELED SECTION ON THE INNER SURFACE OF THE DIAPHRAGM BODY ADJACENT THE LIP FUNCTIONS AS A CAM SURFACE IN CONJUNCTION WITH THE STETHOSCOPE HEAD BODY TO TENSION THE DIAPHRAGM BODY ACROSS THE HEAD. THE STETHOSCOPE HEAD IS FORMED OF A THIN PLASTIC HAVING REINFORCING RIBS ON ITS OUTER SURFACE AND AN INTEGRALLY FORMED OPENING FOR ATTACHMENT OF A BINAURAL TUBE.

Description

Oct. 26, 1971 H U ETAL 3,614,991

STETHOSCOPE CHESTPIECE Filed April 9, 196a United States Patent 3,614,991 STETHOSCOPE CHESTPIECE Gustav F. Machlup and David Littmann, Belmont, Mass., assignors to Minnesota Mining and Manufacturing Company, Maplewood Village, Ramsey County, Minn.

Filed Apr. 9, 1968, Ser. No. 719,927 Int. Cl. A61b 7/02 US. Cl. 181-24 7 Claims ABSTRACT OF THE DISCLOSURE A stethoscope chestpiece construction including a diaphragm formed of a flat thin flexible resilient body having an integral angularly flared lip about its periphery adapted to snap over and engage a complementary shoulder in the body of the stethoscope head. An annular beveled section on the inner surface of the diaphragm body adjacent the lip functions as a cam surface in conjunction with the stethoscope head body to tension the diaphragm body across the head. The stethoscope head is formed of a thin plastic having reinforcing ribs on its outer surface and an integrally formed opening for attachment of a binaural tube.

SUBJECT MATTER OF THE INVENTION The present invention relates to a stethoscope chestpiece having a body and diaphragm combination.

BACKGROUND OF THE INVENTION Most stethoscopes which are commercially available today are formed with a stethoscope body of metal to which is secured a flat diaphragm by a separate rim or securing means. These constructions are relatively expensive to make because the stethoscope chestpiece requires considerable machining. In addition, many stethoscopes of this type have diaphragms which have a tendency to separate from the body when the separable rim inadvertently loosens.

Further, presently available stethoscopes are not completely satisfactory for many medical applications. For example, it is desirable to have a stethoscope chestpiece which is so inexpensive that it is economically feasible to dispose of the chestpiece after a single use. Under these conditions, a doctor can throw away the chestpiece after examining a patient with a contagious disease. Further it is deirable to provide a stethoscope head with readily interchangeable diaphragms which permit the doctor to substitute one diaphragm for another depending upon the particular application for which the diaphragm is intended. A further object of the present invention is to provide a stethoscope chestpiece which is lighter than those heretofore available so that several chestpieces may be carried on ones person without inconvenience. It is also desirable to provide inexpensive non-chilling stethoscopes with as large a diaphragm as possible so as to assure maximum auditory reception.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the previously mentioned difficulties by providing a relatively inexpensive stethoscope chestpiece which is capable of being injection molded in large quantities at costs which are only a fraction of the costs of presently available commercial stethoscope chestpieces.

Another object of the present invention is to provide a very inexpensive stethoscope chestpiece having equal or better auditory sensitivity than those heretofore available. A further object of the present invention is to provide an improved stethoscope chestpiece which may be made of two components only, in which one of the components "ice consists essentially of a diaphragm body with an integrally formed rim capable of being removably interengaged with the body of a stethoscope chestpiece. A still further object of the present invention is to provide an improved inexpensive disposable stethoscope chestpiece which is entirely non-chilling and rugged in character.

In the present invention there is provided a stethoscope chestpiece having a diaphragm formed of an integral diaphragm body and a peripheral rim with the rim adapted to engage a variety of stethoscope chestpiece bodies in such a manner as to stretch the diaphragm body across the stethoscope chestpiece body with sufiicient tension as to assure accurate sound reproduction. In a preferred form of the invention, the diaphragm is used in conjunction with an all plastic stethoscope chestpiece body formed of a thin plastic member and reinforced rims on its outer surface, with the stethoscope chestpiece body having a low flat contour and an integrally formed tubular extension adapted to be engaged by a tube of binaural or other tubular connection.

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 drawings in which:

FIG. 1 is a plan view of a stethoscope showing the invention in the preferred embodiment; and

FIG. 2. is an enlarged cross sectional view taken substantially along the line 22 of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, there is illustrated a stethoscope chestpiece construction which consists essentially of a stethoscope chestpiece body 1 and a diaphragm 2. Preferably the overall height of the chestpiece is about A". In the preferred embodiment both of these components which comprise the entire chestpiece are preferably made of an injection molded plastic. A variety of suitable plastics may be used. It is preferable to make the chestpiece body 1 of polypropylene of various. densities. Alternately high impact polyethylene and an acrylonitrile-butadienestyrene copolymer made by Marbon Chemical Co. under the trade name Cycolac may be used. It is preferable to make the diaphragm 2 of polypropylene. It may also be made of a commercial plastic sold as EEA, an ethylene ethyl acrylate made by Union Carbide Co. The diaphragm material should be more compliant with deflections of the body and tends to contact the body better than the chestpiece material which is relatively harder.

The diaphragm 2 is formed of a diaphragm body 3. The diaphragm has an overall dimension of to 1 /2" for pediatric stethoscopes and 1 /1 to 2%" for adult stethoscopes. The diaphragm body 3 is preferably a circula-r thin flexible resilient member. The thickness of the body 3 may vary depending upon the specific application desired and the particular material used in fabricating the diaphragm body. However, in order to be thin enough to have flexibility as defined herein, .008" to .011" for pediatric stethoscopes and .0109" to .016" for adult stethoscopes are usual. An annular angularly extending lip '4 is continuously formed about the periphery of the diaphragm body 3. This lip 4 is formed of a mass of material having an overall width from point 5 to point 6 which is considerably thicker than body 3. Preferably the thickness should be at least twice the thickness of the diaphragm body 3. This depending lip is preferably arcuate on its outer surface, as illustrated at 6, so as to provide a smooth surface when touched. The innersurface of lip 4 is formed with an undercut 7 adapted to engage a complementary shoulder 8 formed about the periphery of the stethoscope chestpiece body 1. Preferably the stethoscope body .1 is formed with a periphery having its lower surface 10 flared or bevelled slightly upwardly and away from the opening 11. The diaphragm body 3 is thus provided with an annular bevelled surface 14 which is complementary to the bevelled surface 110 of the stethoscope body 1. This annular bevelled surface 14 extends at an angle of 8 to a horizontal plane extending through the annular edge 15. The purpose of this surface 14 is to function as a cam surface which stretches or tightens the body 3 over opening "11 in the body 1. It also tends to bow the center of the body 3 outwardly into a convex configuration and prevents the diaphragm from collapsing inwardly into opening 11. The upper surface 16 of the shoulder 8 is engaged by the inwardly extending portion 17 of the lip 4.

The stethoscope body 1 is preferably formed of a relatively thin wall 10 of plastic material with the wall 10 having a thickness in the order of magnitude of approximately two or three times the thickness of the diaphragm body 3. In addition the outer surface 18- of the body 1 is formed with a plurality of ribs 19 that extend radially outwardly from a center portion 20 on the outer surface of body .1. The center portion 20 is preferably located away from the center of the body 1 and close to the periphery as illustrated in FIG. 1. The height of these ribs 19 may be approximately equal to the thickness of the body 10 as illustrated in FIG. 2.

Integrally formed with the body .1 is a tubular extension 22. This tubular extension 22 has a central opening 23 which extends into the opening 11. The other end of the tubular extension 22 may be connected by frictionally inserting it into a standard flexible rubber or rubber-like tube 24 which may form a portion of a binaural or other suitable mechanism for conveying sound waves.

The diaphragm body 3 may be easily removed from the body 1 and replaced with other diaphragms by simply forcing the annular lip 4 away from the interengaging shoulder 8 and by replacing it by simple snap on pressure of another diaphragm body 2. In this fashion a doctor or other stethoscope user may readily substitute different style or thickness diaphragm bodies 2 on the stethoscope head. If desired the entire head may be removed from the tube 24 since it is merely secured to the tube 24 by frictional interengagement.

Some time it is desirable to firmly position a stethoscope chestpiece on a patients body especially for the purpose of monitoring apical heart sounds during an operation. The present invention of a disposable diaphragm with an integral rim offers an inexpensive opportunity to fix the chestpieces position by covering the outer surface of the diaphragm body 3 with a double sided pressure sensitive adhesive strip or film, as illustrated in somewhat schematic form at 3A. After use the sticky diaphragm may be disposed of and replaced inexpensively and easily.

What is claimed is: p

1. In a stethoscope chest piece construction, a'diaphragm comprising:

a flat, circular, flexible body and a rim integrally formed about the periphery of said body and projecting angularly from one surface of said body, said rim having a cross sectional configuration pro viding a width greater than the thickness of said body,

a smooth outer surface and an undercut formed at the surface of said rim adjacent said one surface, said undercut adapted to engage the periphery of the body of a stethoscope chest piece,

wherein said one surface is an angularly bevelled surface adjacent said undercut, said bevelled surface being remote from the center of said diaphragm body and adapted to engage a bevelled surface of a stethoscope chest piece body complementary thereto.

2. The stethoscope chest piece construction of claim-1 wherein said rim is flexible.

3. The stethoscope chest piece construction of claim 1 having a stethoscope body formed of a wall having. a thickness greater than the thickness of said diaphragm body and having a periphery defining an opening, and said periphery of said stethoscope body having an annular shoulder adapted to be engaged by said rim under: cut.

4. The stethoscope chest piece construction of claim 3 wherein said wall is formed with a plurality of ribs on one surface extending radially from a common point.

5. The stethoscope chest piece construction of claim 4 having a tubular extension integrally formed with said wall and extending outwardly of said one surface of said wall.

6. The stethoscope chest piece construction of claim 1 wherein said one surface has a pressure-sensitive adhesive material secured thereto with said pressure-sensitive material adapted to secure said chest piece to a persons body.

7. A stethoscope chest piece construction of claim 5 wherein said annular shoulder is formed with an annular peripheral wall of greater diameter in a plane remote from said diaphragm body than in a plane closer thereto and said undercut comprises a radial recess in the inner surface of said rim having a configuration shape to receive said annular shoulder.

References Cited UNITED STATES PATENTS- 1,157,428 10/1915 Sheppard 18l24 1,845,795 2/1932 Joseph 18124 2,614,646 10/1952 Eaton 18-1-24 3,470,975 10/1969 Haiken l81-24 872,448 12/1907 Penhallow 18l---24 2,893,507 7/ 1959 Friedman 181-24 FOREIGN PATENTS 1,208,208 9/1959 France 18124 STEPHEN J. TOMSKY, Primary Examiner