An apparatus is presented for accurately calibrating ergometers so that the work rate produced by the particular ergometer being calibrated is accurate. The apparatus includes a dc motor which is coupled directly to the ergometer for rotating it at various speeds. Positioned on the shaft between the dc motor and the ergometer is a torque sensor and tachometer, which feed signals to a power computer for subsequent recording. A speed controller is utilized with the dc motor

Gause, R. L.

English

NASA Technical Reports Server

REPLY TO
ATTN OF: GP
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
WASHINGTON, D.C. 20546
JAN 2 9 1975
TO: KSI/Scientific & Technical Information Division
Attn: Miss Winnie M. Morgan
FROM: GP/Office of Assistant General
Counsel for Patent Matters
SUBJECT: Announcement of NASA-Owned U.S. Patents in STAR
In accordance with the procedures agreed upon by Code GP
and Code KSI, the attached NASA-owned U.S. Patent is being
forwarded for abstracting and announcement in NASA STAR.
The following information is provided:
U.S. Patent No.
 :
Government or
Corporate Employee
Supplementary Corporate
Source (if applicable)
NASA Patent Case No.
NOTE - If this patent covers an invention made by a corporate
employee of a NASA Contractor, the following is applicable:
YES /—/ NO
Pursuant to Section 305(a) of the National Aeronautics and
Space Act, the name of the Administrator of NASA appears on
the first page of the patent; however, the name of the actual
inventor (author) appears at the heading of column No. 1 of
the Specification, following the words "...with respect to
an invention of ..."
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Bonnie L. Woerher
Enclosure
https://ntrs.nasa.gov/search.jsp?R=19750007860 2020-03-19T20:54:25+00:00Z
States Patent [in 3,859,840
[45] Jan. 14, 1975
r<• -rj ERGOMETER CALIBRATOR
[75] Inventor: Raymond L. Cause, Huntsvilie, Ala.
[73] Assignee: The United States of America as
represented by the Administrator of
the National Aeronautics and Space
Administration, Washington, D.C.
[22] Filed: Oct. 31, 1973
[21] Appl. No.: 411,572
[52] U.S. Cl 73/1 R, 73/379
[51] Int. CI G01I 25/00
[58] Field of Search 73/1 R, 1 C, 379
[56] References Cited
UNITED STATES PATENTS
2,784,591 3/1957 Shoor 73/379
3,192,772 7/1965 Tarter 73/379
3,744,480 7/1973 Cause etal. . . . 73/379 X
Primary Examiner—Richard C. Queisser
Assistant Examiner—Frederick Shoon
Attorney, Agent, or Firm—Wayland H. Riggins; L. D.
Wofford, Jr.; John R. Manning
[57] ABSTRACT
An apparatus for accurately calibrating ergometers so
that the work rate produced by the particular ergome-
ter being calibrated is accurate. The apparatus in-
cludes a D.C. motor which is coupled directly to the
ergometer for rotating such at various speeds. Posi-
tioned on the shaft between the D.C. motor and the
ergometer is a torque 'sensor and tachometer, which
feeds signals to a power computer for subsequent re-
cording. A speed controller is utilized with the D.C.
motor.
3 Claims, 3 Drawing Figures
88
'42
74
72^4- '70 ^68
( N A S A ~ C a s e - M F S ~ 2 1 Q 4 5 ~ 1 ) E B G O M B T E R
C A L I B R A T O R Patent ( N A S A ) 5 p CSCL 1«B N75-15932
[Tnclas
08273
PATENTED JAN 141975 3,859.840
88
3,859,840
. 1 2
ERGOMETER CALIBRATOR chometer are fed into a power computer which com-
putes the wattage being used by the D.C. motor for ro-
ORIGIN OF THE INVENTION tati"8 the ° C Aerator fonning part of the ergome-UKI01IN Ui- 1 Hh IN VhN 1 ION .
 tef A speed controller is coupied between the output
The invention described herein was made by an em- 5 of the tachometer and the D.C. motor for enabling the
ployee of the United States Government, and made be motor to be rotated through a given range of speeds
manufactured and used by or for the Government for and holding the speed of the motor constant at the vari-
governmental purposes without the payment of any ous speeds. Thus, by comparing the output signal pro-
royalties thereon or therefor. duced by the apparatus with the output signal produced
BACKGROUND OF THE INVENTION ' ° by the er8ometer il can be determined if the ergometerHACK.UKUUINU ut- 1 Ht l lNVfcNUUN is accurately calibrated. The D.C. motor is mounted on
This invention relates generally to an apparatus for a carriage so that such can be readily maneuvered for
calibrating ergometers, and more particularly to an ap- coupling to the rotatable shaft of the ergometer.
paratus which generates electrical signals that can be Accordingly, it is a general object of the present in-
compared with the output of an ergometer so as to de- 15 vention to provide an improved apparatus for calibrat-
termine if such is producing accurate and true output ing ergometers over a predetermined speed range,
signals. • Another important object of the present invention is
Ergometers are used in controlled stressing, condi- to provide a relatively simple system capable of pro-
tioning or exercising of-people, and are presently being . ducing a dynamic calibration of an ergometer over a
utilized in many health institutions and exercising clin- 20 given speed load.
ics. In some situations, such as when a patient is exer- • Still another important object of the present inven-
cising as part of a recovery program associated with tion is to provide an apparatus for calibrating ergome-
heart disease, it is important to know the exact amount ters which can be readily maneuvered closely adjacent
of work that the patient is developing in peddling the an ergometer and attached thereto,
ergometer. One device designed specifically for use in 25 These and other objects and advantages of the inven-
exercising heart patients is disclosed in U.S. Pat. No. tion will become apparent upon reference to the fol-
3,744,480, granted to Raymond L. Gause, et al., on lowing specification, attendant claims and drawing.
July 10, 1973. Another instance where it is important „„„„,„„.*• ~ .,,. „
to know the exact amount of work required to peddle BRIEF DESCRIPTION OF THE DRAWING
an ergometer is in exercising astronauts while in outer 30 pjQ j js a perspective view of a conventional ergom-
space. It is important to record the work output of the eter having a calibration device constructed in accor-
astronauts so as to analyze such data to determine the dance with the present invention coupled thereto,
exact amount of exercise needed to maintain the astro- FIG. 2 is a block diagram of the calibration device
nauts in proper physical condition. It has been deter- constructed in accordance with the present invention,
mined that, if the astronauts do not receive sufficient 35 and
exercise while in a zero gravity condition for an ex- FIG. 3 is a block diagram illustrating the controls as-
tended period of time, they develop a calcium defi- sociated with the ergometer shown in FIG. 1.
''Store?* caTbe seen that it is very important that
the ergometer being utilized be accurately calibrated. 40
Heretofore, the ergometers were statically calibrated Referring first to FIG. 1 of the drawing, there is illus-
using lever arms and weights. Such a calibration is not trated an ergometer, generally designated by the refer-
practical in all situations due to the time consumed for ence. character 10 coupled to an apparatus, generally
the calibration. designed by the reference character 12, provided for
SUMMARY OF THF TNVFNTION calibrating the components of the ergometer so as to
SUMMARY OF THE INVENTION produce a true and accurate work output indication.
The invention is designed for providing a dynamic The ergometer 10 may be any conventional ergometer,
calibration over a given speed range for ergometers. and the particular one illustrated is that disclosed in
One such ergometer is disclosed in U.S. Pat. No. U.S. Pat. No. 3,744,480.
3,744,480 and includes peddles mounted on a rotatable The ergometer 10 includes a load module 14 which
shaft coupled to a D.C. generator. A variable resistance in normal operation is driven by bicycle-type peddles
load is utilized for varying the torque required to rotate mounted on a rotatable shaft 16. The load module 14,
the D.C. generator. A torque sensor and tachometer as seen in FIG. 3, includes a D.C. motor operated as a
are coupled to the shaft for sensing the rate of rotation generator 18 that has a variable load resistor 20 cou-
and the amount of torque used for rotating the shaft. pled thereto. The shaft 16 is coupled directly to the
The signals from the tachometer and torque sensor are shaft of the generator so that when the shaft 16 is ro-
fed into a multiplier for producing a D.C. signal indica- tated by peddling, such in turn, causes the generator to
live of the work required to peddle the ergometer. be rotated. The load applied to the generator can be
The apparatus constructed in accordance with the ,. varied by adjusting the resistor 20. Variable loading to
present invention includes a D.C. motor, which is cou- the generator 18 is effected by the electrical resistor
pled directly to the shaft upon which the peddles are 20, which can be switched on and off by a control cir-
used for rotating the ergometer. A torque sensor is cou- cuit 22 in accordance with pulses of varying widths,
pled to the shaft which produces a torque signal indi- The details of the control circuit 22 are described in the
eating the torque required to rotate the shaft. A ta- ^ above-mentioned U.S. Pat. No. 3,744,480, and is
chometer is also coupled to the shaft for generating an merely shown in block form in the subject application
electrical signal indicating the speed of rotation of the to set forth one particular ergometer that may be cali-
shaft. The signals from the torque sensor and the ta- brated by the subject invention.
3,859,840
3 ' • ' 4 •'- '..^
A tachometer 24 is coupled to the D.C. generator 18 shaft 82. Any suitable coupling device may be used for
by a. shaft diagrammatically illustrated by broken line coupling the shafts together.
26, and provides a speed output signal to one input of After the platform 68 has been maneuvered along-
a multiplier 28. A torque sensor 30 is mechanically side of the ergometer and coupled to the shaft 16 of the
connected to the shaft of the D.C. generator 18 for pro- 5 load module 14, a speed controller 86 located in a con-
viding a torque signal representative of the torque ap- trol housing 88 is adjusted to supply sufficient power
plied by the operator of the exercise machine 10. This from any suitable power supply, such as shown at 90 to
torque signal is applied to a second input of the multi- the D.C. motor 66. At the particular speed set on the
plier 28. The multiplier 28 provides a direct current speed controller, the torque sensor 76 generates an
output representative of the rate of work being pe- !0 electrical signal representing the torque produced by
formed by the exercise machine 10. Calibration of this the D.C. motor 66 in rotating the load module 14 of the
output by the operator is such that an output of 5 volts ergometer. The torque sensor may be any suitable con-
is representative of the work rate of 300 watts. This ventional torque sensor, such as the one shown in U.S.
output is indicated or read out by first converting it to Pat- No- 3,744,480, which incorporates strain gauges,
a pulse frequency proportional to a voltage by a D.C. 15 Tne torque signal is fed into a power computer 91. The
frequency converter 31,.and then applying the thus electrical signal produced by the tachometer 78 is also
converted output to a counter 32, which counts pulses fed to the power computer which may take the form of
for a predetermined period to derive a direct readout a multiplier that generates a direct current output rep-
in watts. The circuitry thus described associated with resentative of the rate of work being performed in ro-
the ergometer is represented in block form in FIG. 2 by 20 tatinS the load module of the ergometer. The analog
the block 34 entitled ergometer control and the block si8nal from the multiplier is fed directly to a conven-
36 labeled power output ' tional recorder, and is also fed to an analog-to-digital
Referring again to FIG. 1, the load module 14 is suit- converter whose output goes to digital readout unit on
ably mounted on brackets 38 carried on horizontal ,. the power computer. The signal produced by the power
frame members 40. The horizontal frame members are 25 computer 91 is compared with the output signal pro-
in turn supported on a rectangular base plate 42. Ex- duced by.the ergometer ,n order to determine if the er-
tending upwardly from the rectangular base plate 42 is 8ometer 1S callbrated properly. Before starting the call-
. a vertical column 44 that has a pivot joint 46 attached bration tests,-it is essent.al that the apparatus be prop-
thereto. A seat 48 is mounted on another vertical col-
 30
 er
'y Calibrated by conventional means, such as lever
umn 50, which is coupled to the pivot joint 46. Suitable arms and weights.
. . ,. . j u . .u .• i i A A j The output of the tachometer 78 is also fed back to
bracing 52 extends between the vertical column 44 and controller 86 so that a corrective signal can
another spaced vertical column 54 is earned adjacent
 fce fed Qver ,me 94 D c ^^ 66 for * _
the front portion of the ergometer. Extending upwardly .
 {he D c motor at a ^^ d After t|uj er_
from the vertical column 54 and coupled thereto by a 35
 g<fmeter has been calibrated for OI£ particular speed,
pivot joint 56, is still another column 58 into which fhe d controller is adjusted to va^ious e(£ and
handle bars 60 are suitably carried. Positioned on top
 the pr0cess js repeated
of the handle bars 60 is a console 62 having a front
 Qne advantage of the apparatus constructed in ac-
panel 64-which includes appropriate meters and con-
 cordance with the ent invention over conventional
trols sufficient to enable the operator to observe the 40
 static ,oad calibrating systems is that'the accuracy of
performance and work output, while peddling the load •
 such is not affected by heat generated by the ,oad mod.
module 14.
 ule smce tne DC. motor 66 is generally heated at the
The apparatus constructed. in accordance with the
 same rate
present invention is designed to give a dynamic calibra-
 While a preferred embodiment of the invention has
tion over a given sPeed range of the ergometer, and in- 45 begn described using specific terms, such description is
eludes a D.C. motor 66 which is mounted on a steel for illustrative purposes only, and it is to be understood
platform 68. The steel
 Platform has wheels 70 mounted tnat changes and variations may be made without de-
on the bottom thereof so that the apparatus can be parting from the spirit or scope of the following claims,
readily maneuvered adjacent the ergometer. Vertically what is claimed is:
adjustable bolts 72 extend through threaded holes in 50 i. An apparatus for providing a dynamic calibration
the corners of the platform 68 so such can be screwed over a given speed range for an ergometer having a ro-
downwardly in order to raise the wheels 70 off of the tatable shaft coupled to a D.C. generator, a variable re-
supporting platform. Disc-shaped washers 74 are car- sistance load coupled to said generator, a first torque
ried on the bottom of the bolts. When the bolts are • sensor sensing the torque required to rotate said shaft,
screwed downwardly lifting the wheels 70 off of the 55
 a first tachometer for sensing the rate of rotation of said
floor such holds the supporting platform 68 in a fixed shaft, and means coupled to said first torque sensor and
position on the floor. said first tachometer for generating an electrical signal
The D.C. motor 66 has a shaft 74 extending out- representing the work being performed by the ergome-
wardly therefrom to which a torque sensor 76 and a ta- ter, said apparatus comprising:
chometer 78 are coupled in a conventional manner.
 a. a D.C. motor adapted to be coupled to said shaft
The torque sensor 76 and tachometer 78 are suitably for rotating said shaft;
supported ih an upwardly extending U-shaped member b. a second torque sensor coupled to said shaft pro-
80. Extending out the other side of the U-shaped mem- ducing a torque signal indicating the torque re-
ber 80 is a shaft 82, which is coupled by means of a ,- quired to rotate said shaft;
coupler 84 to the shaft 16 of the ergometer. It is noted c. a second tachometer coupled to said shaft generat-
that the peddles of the ergometer 10 have been re- ing an electrical signal indicating the speed of rota-
moved for enabling the coupling of the shaft 16 to the tion of the shaft;
3,859,840
d. means coupled to said second torque sensor and
said second tachometer for generating an electrical
signal indicating the work being performed by said
D.C. motor in rotating said shaft;
e. a speed controller coupled to said D.C. motor for 5
causing said D.C. motor to be rotated at predeter-
mined speeds, and
f. a feedback circuit coupled between said second ta-
chometer and said speed controller supplying a sig-
nal to said speed controller so as to maintain the to
rate of rotation of said D.C. motor constant for a
predetermined setting of said speed controller, •
whereby by comparing the electrical signal repre-
senting work generated by said ergometer with said
electrical signal of said apparatus at various speeds 15
of rotation of said shafts it can be determined if
said ergometer requres calibration.
2. The apparatus as set forth in claim 1 further com-
prising:
a. a carriage supported on a surface;
b. means for mounting said D.C. motor on said car-
riage;
c. said D.C. motor having a rotatable shaft extending
outwardly therefrom, and
d. a mechanical coupling connecting said shaft of
said D.C. motor to said shaft of said D.C. genera-
tor.
3. The apparatus as set forth in claim 2 further com-
prising:
a. rotatable wheels supporting said carriage for en-
abling said carriage to be maneuvered adjacent
said ergometer, and
b. adjustable vertically extending legs carried by said
carriage for engaging said surface to lock said car-
riage in position.
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Ergometer calibrator

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