Fingertip pulse wave sensor

• US 4,971,062 A
• Filed: 03/28/1989
• Issued: 11/20/1990
• Est. Priority Date: 09/24/1988
• Status: Expired due to Fees

• Current Assignee: Misawa Homes Institute of Research & Development
• Original Assignee: Misawa Homes Institute of Research & Development
• Inventors: Ito, Shoji, Hasebe, Noboru
• Primary Examiner(s): Hindenburg, Max
• Assistant Examiner(s): LACYK, JOHN P
• Application Number:
  US07/329,579
• Time in Patent Office: 602 Days
• Field of Search: 128/664-677, 128/632-633, 128/672, 128/677, 128/686, 128/687-690
• US Class Current: 600/473
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure

Abstract

A fingertip pulse wave sensor includes a fingertip cushion supporting member having a fingertip cushion supporting surface, and a nail supporting member having a nail supporting surface which is disposed in opposed relationship with the fingertip cushion supporting surface at an interval smaller than the standard thickness of fingertips. Either of the fingertip cushion supporting member of the nail supporting member is fixed, and the other of the fingertip cushion supporting member and the nail supporting member is hinged. The hinged fingertip cushion supporting member or nail supporting member is urged in the direction in which they are moved to each other by an elastic body which is capable of applying a substantially fixed amount of pressure with respect to the variations in the pivot stroke caused by the variations in the thickness of the fingertips resting on the fingertip cushion supporting member. The fingertip pulse wave sensor also includes a light-emitting element which is disposed on either of the fingertip cushion supporting surface and the nail supporting surface, and a light-receiving element which is disposed on the other of the fingertip cushion supporting surface and the nail supporting surface.

Claims

1. A fingertip pulse wave sensor, comprising:

a casing;

fingertip cushion supporting member hinged relative to said casing and having a fingertip cushion supporting surface;

a nail supporting member fixed relative to said casing and having a nail supporting surface which is disposed in opposed relationship with said fingertip cushion supporting surface at a distance smaller than the standard thickness of fingertips;

a rotatable shaft coupled to the fingertip cushion supporting member;

elastic means for urging said hinged fingertip cushion supporting member toward said nail supporting surface in such a manner that the pressure applied by said elastic means becomes substantially constant with respect to the variations in the pivot stroke caused by the variations in the thickness of said fingertips resting on said fingertip cushion supporting member, the elastic means including one of a constant-load spiral spring and coil spring having one end mounted to the rotatable shaft and another end engaging the casing;

a light-emitting element disposed on either of said fingertip cushion supporting surface and said nail supporting surface; and

a light-receiving element disposed on the other of said fingertip cushion supporting surface and said nail supporting surface.

2. A fingertip pulse wave sensor, comprising:

a casing;

fingertip cushion supporting member fixed relative to said casing and having a fingertip cushion supporting surface;

a nail supporting member hinged relative to said casing and having a nail supporting surface which is disposed in opposed relationship with said fingertip cushion supporting surface at a distance smaller than the standard thickness of fingertips;

a pivot pin mounted on the nail supporting member;

elastic means for urging said hinged nail supporting member toward said fingertip cushion supporting surface in such a manner that the pressure applied by said elastic means becomes substantially constant with respect to the variations in the pivot stroke caused by the variations in the thickness of said fingertips resting on said fingertip cushion supporting member, the elastic means including one of a constant-load spiral spring and a constant-load coil spring, said one of the spiral spring and coil spring having one end mounted to the pivot pin and another end engaging the nail supporting member;

a light-emitting element disposed on either on said fingertip cushion supporting surface and said nail supporting surface; and

a light-receiving element disposed on the other of said fingertip cushion supporting surface and said nail supporting surface.