Exercise Control System

Abstract

An exercise measuring system in which a person's pulse rate while exercising is electronically detected and compared against a desired level. Pickup electrodes are strapped to the person's chest to pick up his pulse rate while he is exercising and this pulse rate is then fed to an electronic indicating device which compares it with a preset rate, or level. Deviations above or below this level are indicated by respective lights. Lights are also provided to respectively indicate when the user's pulse rate is maintained at the preset level and when the pulse rate has been maintained at the preset level for a predetermined length of time.

Parent Case Text

This application is a substitute for U.S. Patent Application Ser. No. 14,741 filed Feb. 24, 1970, a continuation of U.S. Patent Application Ser. No. 631,048 filed Apr. 14, 1967, both of which are now abandoned.

Description

This invention relates to a system for controlling the degree and duration of exercise of a person.

An object is to provide an exercising system including a machine, such as an "Exercycle" brand machine, and an electronic measurer by which a person can exert himself to any desired level as determined by a given pulse rate during exercising.

A more specific object is to indicate when a predetermined length of time a person exercises while his body sustains a given pulse rate has elapsed.

The present invention is suitable for use in evaluating and monitoring programmed exercise or conditioning regimes on the basis of pulse rate and not physical work loads. Thus a conditioned athlete may be able to give a higher work output than a person not used to exercise, and the present invention permits this to be taken into account. During exercising with the present system, a person is required to raise his pulse rate to a predetermined level and maintain this level for a prescribed period of time.

Direct indication of deviation from the person's predetermined desired cardiac rate is provided by a panel light flashing synchronously with his pulse. Negative or positive deviation of pulse rate from a pre-set level is indicated by two panel lights, marked "low" and "high" respectively. When the desired rate is attained, a third light flashes. The latter is positioned in the center between the "low" and "high" lights and is marked "desired." Thus, a decrease in pulse rate is indicated by the flashing of the "low" light, an increase in pulse rate is indicated by the flashing of the "high" light, while the correct pulse rate is indicated by the flashing of the "desired" light.

Before starting to exercise with the present system, a person straps pickup electrodes to his chest in the vicinity of his heart. These in turn are connected to the electronic measurer. Then, starting with a relaxed pulse rate, he begins to exercise on the machine more and more to raise his heart beat to a desired level. When this is attained the "desired" indicator light will flash, and continue to do so for as long as the desired rate (within a small range of deviation) is maintained. An elapsed time indicator, operating in conjunction with the rate counting circuitry is provided to give a quantitative measure of total time of exercise at the desired level.

A better understanding of the invention together with a fuller appreciation of its many advantages will best be gained from the following description given in conjunction with the accompanying drawings in which:

FIG. 1 shows an exercise measuring system embodying the invention;

FIG. 1A shows an enlarged detail of the pickup electrodes;

FIG. 2 is a logic diagram of the electronic measuring portion of the system; and

FIG. 3 is a schematic diagram of the electronic circuitry and time indicator.

The exercise measuring system 10 shown in FIG. 1 comprises an "Exercycle" brand exerciser 12, and an electronic console 14. The person riding the exerciser has strapped to his chest an electrode pad 16, with three, spaced apart electrodes 18 in direct contact with his skin. These electrodes are respectively connected by a "ground" wire and two "input" wires to the input 20 of the console.

The front panel of the console includes a calibrated knob 22 by which a given pulse rate per minute (from 40 to 210 ppm) can be set. When the person's pulse reaches this pre-set level, the "desired" light 24 on the console panel will start to flash. Below this level the "low" light 26 will indicate, and above the level, "high" light 28 will be turned on. On the panel to the right of the rate indicator lights is another calibrated knob 30 by which a given elapsed or running time at the desired pulse level can be dialed into the console. While this time is running, a fourth light 32 shines steadily; when the set time is up, this light goes out. The console of the system is turned on or off by a panel knob 34. Finally, a dial knob 36 will set the circuit to measure elapsed time only when the "desired" light is flashing, or alternatively when either the "desired" or "high" light is flashing.

FIG. 2 is a logic diagram of the electronic measurer showing in simplified form the various stages of the circuit. The first stage comprises a pulse amplifier 40, which is driven by the low level signals from the electrodes at input 20, and whose output of a much higher level is applied to a Schmitt trigger stage 42. The latter provides constant amplitude pulses whose repetition rate is controlled by the rate of pulses applied to input 20. The output of the Schmitt trigger is applied to a next stage 44 comprising a bi-stable multivibrator, which generates a square wave the frequency of which is one half that of the signals from the Schmitt trigger.

The multivibrator stage applies its output to a frequency counter 46 which generates a direct voltage proportional to the multivibrator frequency. The counter is capable of producing a change in voltage for only one pulse of a different repetition rate in a pulse train.

The direct voltage produced by the frequency counter is, in effect, compared against a settable reference voltage; deviation on the low side of the desired pulse rate results in the flashing of the "low" indicator light 26, deviation on the high side results in lighting of the "high" light 28, while approximate matching of the levels results in the flashing of the "desired" light 24. To this end, the output of frequency counter 46 in FIG. 2 is applied to a lamp pulser stage 48 which drives a selected one of the three indicator lights.

Connected to lamp pulser 48 is a totalizer stage 50 which, while the "desired" light is actuated, measures total elapsed time, the length of time to be measured being settable by panel knob 30 previously described.

FIG. 3 shows the complete details of the circuitry shown in logic form in FIG. 2. For convenience, the various stages enumerated in FIG. 2 have been enclosed in dotted outlines and given corresponding reference numerals in FIG. 3. Amplifier 40 in FIG. 3 has input 20 comprising the three terminals 60, 61, and 62, which are connected to respective ones of electrodes 18. Terminals 60 and 62 connect to transistors 64 and 66 which are differentially connected, and terminal 61 is a neutral point, or ground, with respect to terminals 60 and 62. This arrangement allows a balanced input and provides a degree of common mode rejection of noise and unwanted signals. The output of transistors 64 and 66 is amplified by a transistor 68 and then by a transistor 70. Thus, a 2 millivolt signal at terminals 60, 62 produces about a two volt signal at the output of transistor 70.

Schmitt trigger stage 42 includes a transistor 72 and a transistor 74. The former is biased to saturation while the latter is cut off. When a negative pulse from transistor 70 is applied to the base of transistor 72, it turns off and transistor 74 turns on and is clamped into saturation for as long as transistor 72 is off. This produces at the output of transistor 74 a constant amplitude pulse whose width is the base width of the pulse from amplifier stage 40.

The constant amplitude pulse from trigger stage 42 is differentiated through a coupling capacitor 76 and the spikes are applied to a pair of steering diodes 78 and 79 in multivibrator stage 44. One or the other of these diodes conducts, depending upon which of the transistors 80 and 82 is then conducting. Assuming that transistor 80 and diode 78 are at the moment conducting, a negative going spike of voltage from capacitor 76 will turn off transistor 80, which in turn will cause transistor 82 to turn on. The next negative spike from capacitor 76 will turn off transistor 82 and turn on transistor 80, and so on. Thus the multivibrator produces a square wave whose frequency is directly proportional to one half the pulse rate from electrodes 18.

Frequency counter stage 46 includes two silicon controlled rectifiers (SCRs) 84 and 86 respectively connected to the outputs of multivibrator transistors 80 and 82. SCR 84, when triggered on, discharges a storage capacitor 90; similarly SCR 86 is arranged to discharge an identical storage capacitor 92. These capacitors are charged through respective diodes 94 and 96 from a constant current source including a transistor 98.

Assume that in the multivibrator transistor 80 now goes off and transistor 82 goes on. A positive pulse from transistor 82 will be applied to the gate of SCR 86. This turns the latter on and discharges capacitor 92. When the discharge current falls below the minimum "hold on" current of SCR 86, it will then turn off. Capacitor 92 will now begin to charge through its diode 96 and in so doing will reverse bias diode 94 (assuming a charge on capacitor 90 from the previous cycle) thereby stopping the charging of capacitor 90. Capacitor 92 will charge according to the relation V = TI .div. C, where V is voltage, T is time, I is current, and C is capacity. Both current and capacity are constant and so voltage is a linear function of time. In similar fashion, when SCR 84 is turned on, capacitor 90 will be discharged and will stop the charging of capacitor 92. The voltages on these two capacitors in their non-charging states are thus a linear function of the switching rate of the multivibrator. Connected in the constant current source in series with transistor 98 is an adjustable resistor 100, whose setting is controlled by the PPM knob 22 on the panel of the console. This setting also controls the levels of the voltages on capacitors 90 and 92.

Capacitors 90 and 92 are connected to the base of a transistor 102 in lamp pulser stage 48 via respective ones of diodes 104 and 106 and a resistor 107. These diodes alternately sense the more positive of the voltages on capacitors 90 and 92 and transfer this voltage to the base of transistor 102, which is connected as an emitter-follower with a gain of unity. Connected to transistor 102 are transistors 110 and 112 which are arranged as a differential pair connected as shown to a Zener reference diode 114. When the voltage from counter stage 46 rises above or falls below a level determined by Zener diode 114, transistor 110 or 112 will conduct.

Connected to transistor 110 is an amplifer transistor 116 which is connected via a lead 118 to the gate of an SCR 120. The latter is in series with its anode "high" indicator lamp 28. Similarly, transistor 112 is connected to an amplifier transistor 122 which via lead 124 controls an SCR 126. This has in series with itself "low" indicator lamp 26. Next to SCR 126 is a third SCR 128 which is in series with "desired" lamp 24.

The three indicator lamps are connected via a common lead 130 to the output of an SCR 132, whose gate is triggered by signals from the multivibrator. The anode of SCR 132 is supplied with D.C. pulsating at power line frequency via lead 134 from the power supply 136. Thus, whichever indicator lamp is on flashes at the pulse rate output of multivibrator 44.

As mentioned previously SCRs 120 and 126 are respectively turned on by transistors 116 and 122. The pulsating current from SCR 132 automatically turns off the SCRs and allows them to be again turned on by their respective control transistors. SCR 128 is controlled via a lead 138 from a transistor 140. The latter is allowed to turn on when neither of SCRs 120 and 126 is being turned on. Thus "desired" lamp 24 automatically lights when lamps 26 and 28 go out.

Whenever SCR 128 is turned on, an adjacent transistor 142 is also turned on. This energizes a relay coil 144 which in turn closes a switch 146 in the totalizer stage 50. Switch 146 is in series with a timing motor 148 and another switch 150. The latter is controlled by a rotary cam 152 driven by the motor and settable by panel knob 30. When switches 146 and 150 are closed, motor 148 runs, and simultaneously running lamp 32 is lighted. After a pre-set time, cam 152 opens switch 150 and stops the motor.

Elements of the circuit in FIG. 3 which have not been described in detail will be readily understood by those skilled in the art. The above description is intended in illustration and not in limitation of the invention. Various changes in the embodiment set forth may occur to those skilled in the art.

Claims

We claim:

1. An exercise control system adapted for use with means for a person to exercise on, comprising, means for detecting his actual pulse, means for converting the detected pulse rate to a first electrical signal proportional to said detected pulse rate, means for setting and producing a reference electrical signal proportional to a single desired pulse rate, and means for comparing said first electrical signal to said reference signal and for indicating deviation on either the low side or the high side of said desired pulse rate, said comparing and indicating means having no connection to said exercising means.

2. An exercise control system as defined in claim 1 wherein said converting means produces a pulsating signal and includes wave forming and shaping means connected to the output of said detecting means for forming a pulsating square wave whose repetition rate is proportional to the detected pulse rate and means for converting said square wave to said electrical signal, said signal comprising, a d.c. voltage proportional to said detected pulse rate, said setting means being adapted to produce a reference signal comprising a preset reference voltage, said means to indicate deviation including two lamps operatively connected to said comparing means for providing respective light signals proportional to the actual pulse rate, when said d.c. voltage is lower than said reference voltage, and when it is higher than said reference voltage.

3. An exercise control system as defined in claim 2 wherein said indicating means includes a third lamp adapted to produce a light signal when said d.c. voltage matches said reference voltage.

4. The exercise control system as defined in claim 2 in further combination with timing means operatively connected to said comparing and indicating means for actuation thereby when said d.c. voltage matches said reference voltage, including means for indicating the termination of a preselected time period during which said d.c. voltage matches said reference voltage.

5. An exercise control system of the character described including, an electronic transducer to detect a person's pulse rate while exercising and to provide a signal proportional to the pulse rate, said transducer comprising electrode means to sense a person's heart beat, wave forming means to convert the pulse so detected into a repetitive wave whose repetition rate is determined by the frequency of said pulses, and means to convert said repetitive wave into a variable d.c. voltage signal the level of which is proportional to said repetition rate, said system further including comparing means, operatively connected to said means to convert, for comparing said variable d.c. voltage with a predetermined voltage value, and three switch means including "desired," "high," and "low" circuits which respectively control "desired," "high," and "low" indicators, said switch means being operatively connected to said comparing means for selective actuation in response to said comparing means in accordance with whether a said voltage signal is above, below or equal to said predetermined voltage value.

6. The exercise control system in claim 5 wherein said wave forming means includes a Schmitt trigger followed by a bystable multivibrator, and said switch means includes three switch SCR's and a fourth SCR operatively connected with said first three which supplies them with pulsating direct voltage to automatically extinguish any SCR after it is on, said comparing means including means for actuating a particular one of said switch SCR's depending on the ratios of the variable d.c. voltage produced by said means to convert to said predetermined voltage value.

7. An exercise monitoring system comprising, an exercising machine on which a person can exercise at varying levels of exertion, means to detect his pulse rate, and electronic means to convert his pulse rate into light signals proportional to his pulse rate, said electronic means having means for setting a single desired pulse rate and means operatively connected to said setting means and said detecting means for comparing said desired pulse rate with the detected pulse rate and for producing a light signal when said detected pulse rate is at said desired rate, and timing means for indicating that said desired pulse rate has been maintained at the desired level for an indicated time period.

8. An exercise monitoring system as defined in claim 7, wherein a moving part thereof includes means for stopping said timing means after a settable elapsed time.