Frederick U Nelson

US Patent:

42001692, Apr 29, 1980

Filed:

Oct 16, 1978

Appl. No.:

5/951375

Inventors:

Robert D. MacDonald - Stillwater MN
Frederick W. Nelson - Cottage Grove MN

Assignee:

Minnesota Mining and Manufacturing Company - Saint Paul MN

International Classification:

A61B 702

US Classification:

181131

Abstract:

This invention relates to a stethoscope having improved acoustical properties. The improvement comprises twin, smooth-walled sound pathways extending from the chestpiece to the ear tips which are free of sound leakage and each pathway has a constant diameter along its entire length.

US Patent:

42390893, Dec 16, 1980

Filed:

Aug 9, 1979

Appl. No.:

6/065146

Inventors:

Frederick W. Nelson - Cottage Grove MN

Assignee:

Minnesota Mining and Manufacturing Company - Saint Paul MN

International Classification:

A61B 702

US Classification:

181131

Abstract:

A two-microphone stethoscope chestpiece is dislcosed wherein the locking mechanism for securing the shaft within the body of the chestpiece against axial movement and the indexing mechanism for aligning the shaft with the selected microphone are combined into a single spring having a C-shaped portion and a leg extending axially from one end thereof. The spring is positioned partially within grooves in the shaft and partially within corresponding slots in chestpiece body. Upon rotation of the shaft, the leg portion of the spring clicks into one of two opposed slots in the chestpiece body and secures the shaft in proper alignment with the selected microphone.