EP0065519A1 - Detecteur d'impulsions - Google Patents

Detecteur d'impulsions

Info

Publication number
EP0065519A1
EP0065519A1 EP19810902176 EP81902176A EP0065519A1 EP 0065519 A1 EP0065519 A1 EP 0065519A1 EP 19810902176 EP19810902176 EP 19810902176 EP 81902176 A EP81902176 A EP 81902176A EP 0065519 A1 EP0065519 A1 EP 0065519A1
Authority
EP
European Patent Office
Prior art keywords
band
pulse
pulse detector
detector
metal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19810902176
Other languages
German (de)
English (en)
Inventor
Harry Lotman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0065519A1 publication Critical patent/EP0065519A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow
    • A61B5/024—Measuring pulse rate or heart rate
    • A61B5/02438—Measuring pulse rate or heart rate with portable devices, e.g. worn by the patient

Definitions

  • the present invention is directed towards a pulse detector and, more particularly, to a portable pulse detector which monitors the heart rate by the detection of pulses and provides a visual indication of the heart rate of the user.
  • Pulse detectors of the foregoing type are well known in the prior art. Such detectors generally include a pulse-detecting transducer for generating output signals representative of the patient's pulse, an electronic circuit for evaluating the patient's pulse rate and a display for providing a visual indication of the patient's pulse rate.
  • the prior art patents fall into two broad classes: those which detect the pulse of the patient using pressure transducers and those which detect the pulse of the patient using light transducers.
  • the foregoing class of patents is exemplified by U. S. Patent No. 3,426,747 which uses a pressure transducer which is biased against the radial artery of the patient and detects changes in the size of the radial artery resulting from the rush of blood therethrough.
  • the latter class of patents is exemplified by U. S. Patent No. 3,359,975 which uses a light transducer attached to the earlobe of the patient and detects the rush of blood through the earlobe.
  • prior art light transducer pulse detectors have not met with great commercial success since they generally must be attached to the earlobe of the patient and are therefore unattractive or must be placed against the finger of the patient and have not been particularly accurate.
  • Prior art pressure responsive pulse detectors are less obtrusive but have been unable to consistently provide an accurate pulse reading.
  • the inability of prior art pressure responsive pulse detectors to provide consistently accurate readings stems from the need to locate pressure transducers at a location corresponding to the radial artery, and the generation of noise signals resulting from movement of the wrist of the individual. It is a primary object of the present invention to overcome these drawbacks by providing a pressure responsive portable pulse sensor which need not be accurately placed over the radial artery and which is less sensitive to the generation of noise signals.
  • the present invention is directed towards a pulse detector comprising: a band having a generally hoop-like shape; hoop stress sensing means for detecting the tensing of said band and for generating a pulse signal each time said band is tensed by the pulse of a person wearing said band; and circuit means responsive to said pulse signals generated by said hoop stress sensing means for generating an output signal indicative of the value of the pulse of said person wearing said band.
  • the pulse detector takes the general form of a wristwatch having a casing housing both the hoop stress sensing means and the circuit means and an elastic band coupled to the casing.
  • the elastic band is adapted to fit tensively around the wrist of the wearer and is mechanically coupled to the hoop stress sensing means which is preferably a piezoelectric transducer.
  • the stored signals are read out of the memory at a high frequency which has the effect of compressing time and dilating frequency. As a result, the random noise components become widely separated in frequency leaving a predominant high frequency signal whose primary frequency (determined by the frequency of the pulse signals alone) is N times the frequency of the pulse signals.
  • a phase locked loop is utilized to determine the dominant frequency of the signal read out of the memory and for generating an output signal indicative thereof.
  • this signal is applied to an LCD (LIQUID CRYSTAL DISPLAY) display which provides a numerical indication of the pulse of the patient wearing the pulse detector.
  • LCD LIQUID CRYSTAL DISPLAY
  • FIG. 1 is a perspective of a pulse detector in accordance with the principles of the present invention.
  • Figure 2 is a side view, partially schematic and partially in section, of the pulse detector of Figure 1 with a modified wristband.
  • Figure 2A is a plan view taken along lines 2A-2A of Figure 2.
  • Figure 3 is a sectional view of a clasp forming part of the wristband illustrated in Figure 2.
  • Figure 4 is a block diagram of the pulse analysis circuit of Figure 2.
  • pulse detector 10 is similar in shape to a wristwatch and includes a casing 12 and an elastic band 14. As best illustrated in Figure 2, the casing 12 houses a piezoelectric transducer 16, a pulse analysis circuit 18 and an LCD display 20. Display 20 is visible through an opening 22 formed in the casing 12 and provides a visual indication of the patient's pulse. While this embodiment represents the preferred structure of the invention, it should be recognized that other embodiments may be employed without departing from the spirit or scope of the invention.
  • the band 14 could be adapted to fit around the neck of the patient and/or the pulse analysis and display circuits can be located at a remote location and could contain time keeping and out of limits visual and/or audio alarm functions as well.
  • the band 14 is connected to a thin disc 24 so that tensive forces produce a bending moment on disc 24.
  • the piezoelectric transducer 16 mounted on the disc 24 is responsive to the bending moment.
  • the disc sits on a pedestal 25 located on the bottom of case 12.
  • the band 14 extends through openings 26 and 28 in case 12 and is attached to the disc 24 off the plane of the disc 24 so that tensive forces bend the disc about the pedestal that is acting as a fulcrum.
  • the pedestal 25 may be formed of rubber which is bonded to both disc 24 and the case 12.
  • band 14 When band 14 is placed around the wrist of the patient, the band 14 assumes a generally oval shape.
  • the enlarged circumference of the patient's wrist tends to stretch wristband 14 circum ferentially and thereby stress the same.
  • This circumferential stress is referred to herein a "hoop stress”.
  • This stress is transmitted to disc 24 and is detected by piezoelectric transducer 16 which generates output signals indicative thereof.
  • the output signals generated by transducer 16 are of two primary types: relatively constant frequency pulses generated in response to each heartbeat of the patient and relatively random pulses (noise) generated as a result of movement of the patient's wrist. These signals take the general form illustrated at 30 in Figure 4. These pulses are applied to pulse analysis cir cuit 18 which evaluates the same and generates an outputsignal indicative of the pulse rate of the individual wearing pulse detector 10.
  • pulse analysis circuit 18 A block diagram of pulse analysis circuit 18 is set forth in Figure 4 and will be described in further detail below. As should be apparent from the foregoing, the ability of the pulse analysis circuit 18 to accurately determine the pulse rate of the patient is determined in part by the sensitivity of the transducer 16 to variations in the circumference of the patient's wrist.
  • the sensitivity of transducer 16 is, in turn, a function of the degree of mechanical coupling between the band 14 and the patient's wrist. If the band 14 is too loosely coupled to the wrist of patient, small changes in the diameter of the patient's wrist will cause little or no increase in the tensive forces in wristband 14. If the band 14 is too tightly connected to the patient's wrist, it could stop the flow of blood through the radial artery and thereby effectively remove the pulse from the wrist. Accordingly, the tightness of the band 14 should be adjusted to a level between these two extremes. Yet another factor effecting the quality of the output signal generated by transducer 16 is the tensile sensitivity of disc 24. Thus, the disc 24 may have a certain range of tensile forces in which its dimensions are most highly effected by changes in tension. The median tension placed on disc 24 by wristband 14 should be within a desired sensitivity range of disc 24.
  • wristband 14 is divided into two halves 14a and 14b.
  • Band half 14a is soldered to casing 30 at 31 while band half 14b is releasably coupled to casing 12 by releasable clamp 32.
  • Clamp 32 includes a cylindrical stop 34 which is biased into contact with band end 14b by compression spring 36.
  • a pair of cam followers 38 (Fig. 2) extend from opposite axial sides of stop 34 and extend through respective cam slots 40 located on either side of casing 30.
  • band half 14b When band half 14b is moved to the left as viewed in Figures 2 and 3, stop 34 is biased towards the base 42 of housing 30 thereby pinching band half 14b and preventing further movement to the left. As a result of the foregoing, band half 14b is freely movable into casing 30 but cannot be freely moved out of casing 30. If the patient wishes to remove band half 14b from casing 30, he will grasp the handles 44 connected to the end of either cam follower 38 and pull hold stop 34 up and to the right as viewed in Figure 3. As a result, band half 14b will no longer be pinched between stop 34 and base 42 and may be freely withdrawn from casing 30.
  • pulse analysis circuit 18 receives an input signal 30 from input transducer 16.
  • Input signal 30 includes both the pulse signals generated in response to the flow of blood through the patient's radial artery and noise signals responsive to various factors such as the movement of the patient's wrist.
  • the pulse signals have a relatively uniform frequency f while the noise signals are quite random.
  • the fundamental frequency of signal 30 is the pulse frequency f.
  • the output of transducer 16 is applied to a band pass filter 46 which preferably passes a range of between .5 and 4 Hertz, although other ranges may be used.
  • Filter circuit 46 serves to remove a significant portion of the noise from the input signal 30. A substantial amount of noise does, however, remain in this signal.
  • A/D converter 50 converts the analog signal at its input to a digital signal (preferably a four bit BCD signal) which is applied to input lines 58 of recirculating memory 52.
  • Memory 52 is an N stage shift register (N being an integer greater than 1) which stores N four bit digital signals representative of the shape of the input signal 30 over the last several seconds.
  • memory 52 is a sixty-four stage memory which may be formed of four parallel sixty-four bit shift registers. Appropriate shift registers are manufactured by RCA under the product denation CD4031A.
  • Memory 52 is operable in two modes: an input mode and a recirculate mode.
  • memory 52 applies the four bit signal appearing on lines 58 to the first stage of memory 52 each time a clock signal CL1 is applied to the clock input CL of memory 52.
  • the recirculate mode the four bit digital signal appearing on output lines 60 of memory 52 is applied to the first stage of memory 52 each time the clock signal CL1 is applied to clock input CL of memory 52.
  • each of the four bit words stored in memory 52 are shifted one stage towards the output whenever a clock signal CL1 is applied to the clock input CL of memory 52.
  • System clock 54 generates clock signals CL1, CL2 and CL3 which may, for example, have frequency of 1092, 1.066 and 68 Hz, respectively.
  • System clock 54 may include a crystal oscillator and an appropriate set of digital counters for generating the desired signals.
  • Memory control counter 56 is an N+1 counter whose count increases by one each time a new clock pulse CL1 is applied to its count input CL.
  • the output of counter 56 is at a binary "1" level whenever its count is full (i.e., it has received N+1 clock pulses) and is at the binary "0" level at all other times.
  • the count in counter 56 is reset to 1 responsive to the next clock pulse applied thereto.
  • the output of counter 56 is at the binary "0" level for N consecutive clock pulses and at the binary "1" level for one clock pulse.
  • Memory 52 operates in the input mode whenever a binary "1" is applied to its MODE input and operates in a recirculate mode whenever a binary "0" is applied thereto.
  • D/A converter 62 converts the digital signals appearing on output lines 60 of memory 52 to an analog signal having a shape substantially identical to the shape of input signal 30 but having a frequency 64 times as great. This signal is applied to band pass filter 64 which serves to remove extraneous frequency components from the signal appearing at the output of D/A converter 62.
  • band pass filter 64 serves to remove extraneous frequency components from the signal appearing at the output of D/A converter 62.
  • phase locked loop 64 will have a fundamental frequency 64f which is 64 times greater than the fundamental frequency f (the pulse frequency of the patient) of the input signal 30
  • This signal is applied to a phase locked loop 66 which generates an output signal whose frequency is equal to the fundamental frequency (64f) of the output of filter 64.
  • any suitable phase locked loop may be used, one such circuit is manufactured by RCA under the product designation CD4046.
  • phase locked loop 66 By adding appropriate external components (resistors and capacitors) to phase locked loop 66, it is possible to limit the range of output signals generated by phase locked loop 66 to a particular frequency band. It is preferred that this frequency band correspond to the frequency band of band pass filter 64.
  • phase locked loop 66 has a frequency 64f which is substantially independent of frequency components of the input circuit 30 which are attributable to noise.
  • This output is applied to a counter 68 which is preferably, but not necessarily, a three digit BCD counter.
  • the count in counter 68 is increased at a rate determined by the frequency of the output of phase locked loop 66 whenever a binary "1" is applied to its enable input ENB.
  • the enable input ENB of counter 68 receives the clock signal CL2 generated by system clock 54.
  • clock signal CL2 preferably has a frequency of 1.066Hz which will enable counter 68 for 15/16 ths of a second.
  • the clock signal CL2 is also applied to one shot 70 which generates a single pulse at its output responsive to each clock pulse CL2.
  • the pulse appearing at the output of one shot 70 is applied to one shot 72 which also generates a single pulse which clears the count in counter 68.
  • the count in counter 68 is equal to the pulse rate in pulses per minute of the patient wearing pulse detector 10 at the instant one shot 70 produces an output pulse.
  • the pulse generated by one shot 70 is applied to the latch input LT of latch and decoder LCD display driver circuit 74.
  • Driver circuit 74 latches the signal appearing at the output of counter 68 responsive to the pulse generated by one shot 70. Accordingly, driver circuit generates a three digit BCD signal corresponding to the pulse rate of the patient.
  • driver circuit 74 is comprised of three parallel latch and decoder LCD display driver circuits manufactured by RCA under the product designation CD4543.
  • Display 20 is preferably a three digit LCD display manufactured by Beckman under the product designation 708-6-2.
  • Driver circuit 74 and display 20 are enabled by the clock pulses CL3 generated by system clock 30 which preferably has a frequency of 68Hz. If desired, an alarm circuitry can be added to pulse analysis circuit 18 to alert the patient that his pulse rate is too high or too low.
  • the output of counter 68 can be coupled to a pair of comparators one of which compares the output of counter 68 to a predetermined minimum pulse rate (e.g., 35 pulses per minutes) and the other of which compares the output of counter 68 to a predetermined maximum pulse rate (e.g., 150 pulses per minute).
  • the output of both counters can be coupled to an alarm circuit which goes off whenever the first counter determines that the actual pulse rate is below the predetermined minimum count and whenever the second count er determines that the pulse rate is above the predetermined maximum pulse rate .
  • means for example , a pair of potentiometers

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Cardiology (AREA)
  • Biomedical Technology (AREA)
  • Medical Informatics (AREA)
  • Biophysics (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Physiology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Physics & Mathematics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)

Abstract

Detecteur d'impulsions portatif (10). Le detecteur d'impulsions (10) comprend une bande (14) ayant la forme d'un anneau et est concu pour s'adapter autour du poignet de l'usager. Un circuit de detection des contraintes de l'anneau (16) detecte la tension de la bande et produit un signal pulse a chaque fois que la bande est tendue par l'impulsion d'une personne portant la bande. Un circuit d'evaluation des impulsions (18) sensible aux signaux d'impulsions produit un signal de sortie indiquant la valeur de la frequence du pouls de la personne portant la bande.
EP19810902176 1980-09-11 1981-07-27 Detecteur d'impulsions Withdrawn EP0065519A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US18617980A 1980-09-11 1980-09-11
US186179 1980-09-11

Publications (1)

Publication Number Publication Date
EP0065519A1 true EP0065519A1 (fr) 1982-12-01

Family

ID=22683943

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19810902176 Withdrawn EP0065519A1 (fr) 1980-09-11 1981-07-27 Detecteur d'impulsions

Country Status (2)

Country Link
EP (1) EP0065519A1 (fr)
WO (1) WO1982000950A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4909260A (en) * 1987-12-03 1990-03-20 American Health Products, Inc. Portable belt monitor of physiological functions and sensors therefor
EP3241491B1 (fr) * 2014-12-30 2021-05-26 Arnuxon Pharm-sci Co. , Ltd. Sangle de santé intelligente

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3154067A (en) * 1961-10-11 1964-10-27 Robert L Gannon Body function sensor
US4038976A (en) * 1975-03-14 1977-08-02 Hardy Frank M Pulse indicator
US4058118A (en) * 1976-03-19 1977-11-15 Bunker Ramo Corporation Pulse counter
US4185621A (en) * 1977-10-28 1980-01-29 Triad, Inc. Body parameter display incorporating a battery charger
US4202350A (en) * 1978-05-15 1980-05-13 Walton Charles A Device for measuring pulse, breathing and running rate for joggers

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8200950A1 *

Also Published As

Publication number Publication date
WO1982000950A1 (fr) 1982-04-01

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