# US 4,129,124 A · Pulse-rate indicator

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- Number: US 4,129,124 A
- Document ID: US4129124A
- Status: Granted
- Kind: A
- Application number: 05/767,623
- Filed: 1977-02-10
- Granted: 1978-12-12
- Earliest claimed: 1976-03-23
- Assignees: Elektro-Apparatebau Olten AG
- Inventors: Rene A. Thalmann
- Web page: https://patentgrep.com/patent/US4129124A

## CPC

- A61B 5/681: {Wristwatch-type devices}
- A61B 5/02416: {using photoplethysmograph signals, e.g. generated by infrared radiation (A61B5/14552 takes precedence)}
- A61B 5/02438: {with portable devices, e.g. worn by the patient}
- A61B 2560/029: adapted for auto-initiation
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A pulse-rate indicator having electro-optical means for converting pulse beats into electric measuring pulses, means for generating a number of timing pulses derived from measuring pulses, means for calculating the pulse-rate from the number of timing pulses, means for displaying the pulse-rate, and a pushbutton for rendering the indicator operative, the electro-optical means being disposed in the pushbutton for generating the electric measuring pulses as a function of the perfusion of blood in a human fingertip pressing upon the pushbutton.

## Claims

### Claim 1

A pulse rate indicator of the type having a current supply circuit, means for converting pulse beats into electric measuring pulses, and a pushbutton for operating said indicator, the improvement comprising a casing to which a strap is attached for mounting the casing on the wrist of the wearer, said pushbutton being mounted on said casing, said current supply circuit including a switch that is located in said casing and that is operable in response to depression of said pushbutton to close the circuit thereto, a measuring circuit located in said casing for ascertaining the pulse rate per minute based on a predetermined number of said electric measuring pulses, digital indicating means located in said casing and responsive to said measuring circuit for visually displaying the pulse rate per minute as ascertained by said measuring circuit, electro-optical means located in said pushbutton and being responsive to contact of a human fingertip therewith for generating said electric measuring pulses as a function of the perfusion of blood in said fingertip, said pushbutton having spaced recesses formed therein over which said fingertip is placed during the pulse measuring operation, said electro-optical means including a light source disposed in one of said recesses and a photosensitive element disposed in the other of said recesses, and means for controlling the pressure applied by said fingertip to said pushbutton so that sufficient pressure is applied to said pushbutton to close said switch and so that the pressure of the fingertip is limited in order to obtain a proper measurement of the perfusion of blood therein.

### Claim 2 (depends on 1)

A pulse rate indicator as claimed in claim 1, said controlling means including a depression formed in said casing, through which said pushbutton extends, the configuration of said depression being generally concave and corresponding to the shape of the human fingertip for the accommodation thereof, wherein said depression limits the inward movement of said fingertip to provide for closing of said switch and for proper measurement of the perfusion of blood in said fingertip by said electro-optical means and measuring circuit.