PORTABLE BATTERY-POWERED INSTRUMENT FOR VISUALIZING THE PERIPHERAL PULSE WAVEFORM AND PULSE RATE

• US 3,646,931 A
• Filed: 02/25/1970
• Issued: 03/07/1972
• Est. Priority Date: 02/25/1970
• Status: Expired due to Term

• Current Assignee: Donald J. Sass, Jerry A. Phelps
• Original Assignee: Donald J. Sass, Jerry A. Phelps
• Inventors: Phelps, Jerry A., Sass, Donald J.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/014,143
• Time in Patent Office: 741 Days
• Field of Search: 128/2.5A,2.5C,2.5M,2.5P,2.5Q,2.5R,2.5S,2.5T,2.5V,2.6F,2.06
• US Class Current: 600/502
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/339 Displays specially adapted therefor
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 5/7242 using integration

Abstract

A compact transistorized pulse detector comprising a strain gauge attached to a finger. The output signal is amplified an filtered to trigger a monostable multivibrator, which signal is then integrated to give a readout of the pulse rate on a meter. The pulse waveform is also visually displayed on a small, battery-powered CRT.

Claims

1. Apparatus for detecting the pulse of an individual comprising:

a strain gauge for producing electrical signals representative of the pulse waveform, said strain gauge adapted to be attached to a digit of said individual;

circuitry coupled to said strain gauge for modifying said signals;

a differentiator coupled to said circuitry for differentiating said modified signals to provide spike signals;

a monostable multivibrator coupled to said differentiator for producing a rectangular pulse for each spike signal;

an integrator coupled to said monostable multivibrator for integrating said rectangular pulses;

a first display means coupled to said integrator for indicating the pulse of said individual;

said circuitry comprising a Wheatstone bridge circuit, wherein said strain gauge is a miniature semiconductor and forms one arm of said Wheatstone bridge circuit whereby said bridge circuit transmits a pulse signal upon detection of a pulse by said strain gauge;

amplifier means coupled to said bridge circuit for amplifying said pulse signal;

filter means coupled to said amplifier for removing 60 Hz. interference;

a 1 Hz. low-pass filter coupled to said filter means for removing the dicrotic notch from the pulse waveform;

a level detector coupled to said low-pass filter for providing a step change in voltage for each pulse signal, said level detector also coupled to said differentiator;

an audible signal generator coupled to said level detector for audibly indicating each pulse signal detected by said strain gauge;

said first display means comprising a milliammeter; and

a second display means comprising a cathode-ray tube having a very small face size.