Blood pressure measuring apparatus

• US 4,947,855 A
• Filed: 02/16/1989
• Issued: 08/14/1990
• Est. Priority Date: 02/20/1989
• Status: Expired due to Term

• Current Assignee: Omron Healthcare Company Limited (Omron Corporation)
• Original Assignee: Colin Electronics Co., Ltd.
• Inventors: Harada, Chikao, Yokoe, Hifumi
• Primary Examiner(s): Howell, Kyle L.
• Application Number:
  US07/310,898
• Time in Patent Office: 544 Days
• Field of Search: 128/672, 128/677, 128/687-690
• US Class Current: 600/485
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure

Abstract

A blood pressure measuring apparatus having a housing detachably set on a body surface of a subject, a pressure sensor accommodated in the housing such that the pressure sensor is opposed to the body surface when the housing is set on the body surface, the pressure sensor being pressed against the body surface so as to detect pulse wave produced from an arterial vessel of the subject, the pressure sensor generating pulse wave signal representing the detected pulse wave, a pressing device for pressing the pressure sensor against the body surface, and a control device for determining blood pressure in the arterial vessel based on the pulse wave signal supplied from the pressure sensor, the pressing means and the control means being accommodated in the housing.

Claims

1. A blood pressure measuring apparatus comprising:

a housing detachably set on a body surface of a subject;

a cylindrical member accommodated in said housing;

a pressure sensor secured to one of axial ends of said cylindrical member, said pressure sensor being opposed to said body surface when said housing is set on said body surface, said pressure sensor being pressed against said body surface so as to detect pulse wave produced from an arterial vessel of said subject, said pressure sensor generating a pulse wave signal representing the detected pulse wave;

pressing means for pressing said pressure sensor against said body surface by moving said cylindrical member toward said body surface, said pressing means comprising (a) an externally threaded member secured to said housing and having an axis, said axis being substantially perpendicular to said body surface when said housing is set on said body surface, (b) an internally threaded member engaged with said externally threaded member and having a multiplicity of outer teeth formed in an outer circumference thereof, (c) a motor having an output shaft, and (d) a pinion secured to said output shaft of said motor and engaged with said outer teeth of said internally threaded member, the other axial end of said cylindrical member being fitted on said externally threaded member and engaged with said internally threaded member such that said cylindrical member is coaxial with said externally and internally threaded members,

said pressing means further comprising (e) a means for guiding said cylindrical member along said axis of said externally threaded member without causing rotation of said cylindrical member about said axis, and (f) a means for permitting said internally threaded member to be rotated relative to said cylindrical member on said externally threaded member and thereby be moved together with said cylindrical member along said axis, whereby said pressure sensor secured to said cylindrical member is moved along said axis toward or away from said body surface without rotation of said pressure sensor about said axis when said motor is operated and consequently said internally threaded member is rotated on said externally threaded member and thereby is moved along said axis;

control means for determining an optimum pressing force of said pressing means based on said pulse wave signal, and controlling said pressing means to press said pressure sensor against said body surface with said optimum pressing force, said controlling means determining a blood pressure in said arterial vessel based on the pulse wave signal supplied from said pressure sensor pressed with said optimum pressing force; and

said pressing means and said control means being accommodated in said housing.

2. The apparatus as set forth in claim 1, further comprising a display device for displaying said blood pressure, said display device being provided on one of opposite outer surfaces of said housing, the other of said opposite outer surfaces being opposed to said body surface when said housing is set on said body surface.

3. The apparatus as set forth in claim 1, wherein said pressure sensor includes:

a semiconductor chip; and

a plurality of pressure-sensitive semiconductor elements arranged along a line on said semiconductor chip, each of said semiconductor elements generating the pulse wave signal.

4. The apparatus as set forth in claim 3, wherein said control means selects one of said plurality of pressure-sensitive semiconductor elements which is located right above said arterial vessel, said control means monitoring said blood pressure of said subject based on the pulse wave signal from the selected semiconductor element.

5. The apparatus as set forth in claim 1, wherein said control means controls the pressing force of said pressing means applied to said pressure sensor, by changing the operation amount of said motor based on said pulse wave signal from said pressure sensor.