The stethoscope has long been an important part of medical diagnostics. Examples of such diagnostic stethoscopes are disclosed in U.S. Pat. Nos. 4,440,258; Des. 277,890; 4,475,619 and 4,995,473 the entire contents of each of which are herein incorporated by reference.
An important element of the stethoscope from the user's point of view is the ear tips as they determine much of how comfortable the instrument will be perceived in use. It is also known that a good acoustic seal between the ear tip and the ear is of great importance. Small leaks to the atmosphere or sound blockages in that location may cause attenuation of the sound energy or sound quality that is ultimately delivered to the ear.
Drawing lesser attention perhaps, but also important is that such ear tips should be capable of being removed for cleaning. Once cleaned, the ear tips may be replaced on the ends of the eartubes. Many cycles of such removal and replacement should be withstood by ear tips, since wax secretions are detrimental to many elastomers, and since buildup at the ear tip my cause blockage of the sound path. Also, such buildup may provide a vector for spreading infection.
Coassigned U.S. Pat. Nos. 4,913,259 and 4,852,684 (both to Packard et al. and which are herein incorporated by reference) disclose a compressible ear tip and its use on a stethoscope. It shows a non-porous elastomeric ear tip having a shoulder. Commercial embodiments of the ear tips shown in these patents have been sold more than one year prior to the filing date of the present application by Minnesota Mining and Manufacturing Co. (3M) of St. Paul, Minn. for use with the 3M Littman.TM. Master Cardiology and the 3M Littmann.TM. Cardiology II stethoscopes.