U.S. patent number 3,869,121 [Application Number 05/376,873] was granted by the patent office on 1975-03-04 for proportioned resistance exercise servo system.
Invention is credited to Evan R. Flavell.
United States Patent |
3,869,121 |
Flavell |
March 4, 1975 |
PROPORTIONED RESISTANCE EXERCISE SERVO SYSTEM
Abstract
A proportional resistance exercise servo device. User
interfacing means is connected to a drive shaft so that the user
applies force to said drive shaft and vice versa. The device
applies braking force to the drive shaft as it is rotated in a
first direction by user-exerted force on the interfacing means, in
a braking mode; and it applies power to drive the drive shaft in a
second direction and thereby exerts force on the interfacing means,
in a power mode. Direction reversal means automatically stops the
braking at a first limit and thereafter applies power thereto, and
automatically stops the power at a second limit and thereafter
begins braking it. Both the braking and powering are programmed,
but feedback alters the program in accordance with the user's
performance. Acceleration and deceleration are controlled. Various
performance parameters are displayed or recorded.
Inventors: |
Flavell; Evan R. (Astoria,
OR) |
Family
ID: |
26954143 |
Appl.
No.: |
05/376,873 |
Filed: |
July 5, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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270219 |
Jul 10, 1972 |
|
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Current U.S.
Class: |
482/2; 482/902;
482/901 |
Current CPC
Class: |
A61B
5/22 (20130101); A63B 21/0058 (20130101); A63B
21/153 (20130101); A63B 2220/58 (20130101); Y10S
482/902 (20130101); A63B 2220/54 (20130101); A63B
2220/34 (20130101); Y10S 482/901 (20130101); A63B
21/0053 (20130101); A63B 2220/30 (20130101) |
Current International
Class: |
A63B
21/005 (20060101); A61B 5/22 (20060101); A63B
21/00 (20060101); A63B 24/00 (20060101); A63b
021/24 () |
Field of
Search: |
;273/72,73,79R,DIG.6
;128/25R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Marlo; George J.
Assistant Examiner: Taylor; Joseph R.
Attorney, Agent or Firm: Owen, Wickersham & Erickson
Parent Case Text
This is a division of application Ser. No. 270,219, filed July 10,
1972.
Claims
I claim:
1. An exercise device including in combination:
resistance means for providing in each of two opposite directions
exercise resistance proportioned to the force applied by the
user,
reversing means connected to said resistance means for causing said
resistance means to reciprocate automatically between two
predetermined limits, and
regulating means connected to said resistance means for applying
predetermined control of acceleration and deceleration to said
resistance means as it approaches and departs from each of said
limits at which the direction is automatically reversed.
2. An exercise apparatus including in combination:
resistance means for providing in each of two opposite directions
exercise resistance proportioned to the force applied by the user,
said resistance means comprising an electrical generator driven by
the user and generating an output current, a braking load across
said generator, and means for dissipating the current output of
said generator through said load, thereby providing dynamic braking
of said user-driven generator, and
reversing means connected to said resistance means for causing said
resistance means to reciprocate automatically between two
predetermined limits.
3. The exercise apparatus of claim 2 having means for proportioning
the degree of said dynamic braking to the speed of the
generator.
4. An exercise apparatus including in combination:
resistance means for providing in each of two opposite directions
exercise resistance proportioned to the force applied by the user,
said resistance means comprising a combination motor-generator
driven by the user and generating an output current across a load
resistance, and means for alternately powering said motor-generator
and dissipating its current output across its said load resistance
to provide dynamic braking of said motor generator, and
reversing means connected to said resistance means for causing said
resistance means to reciprocate automatically between two
predetermined limits.
5. The exercise apparatus of claim 4 having means for proportioning
said powering and dynamic braking to the speed of said
motor-generator.
6. An exercise apparatus comprising
a movable device adapted for driving relation with a user,
resistance means connected to said device for providing said device
with exercise resistance by supplying driving power to said device
in one direction of its movement and by supplying braking force to
said device in the opposite direction of its movement, and
means connected to said device for automatically reversing the
direction of movement of said device at each of two preset
limits.
7. The exercise apparatus of claim 6 having connected to said
device means for controlling the rates of acceleration and
deceleration of said device as it approaches each of said
limits.
8. A proportional resistance exercise device, including in
combination:
a drive shaft,
user interfacing means connected to said drive shaft in driving
relation thereto and through which the user applies force to said
drive shaft and vice versa,
braking means for applying braking force to said drive shaft as it
is moved in a first direction by user-exerted force on said
interfacing means, in a braking mode,
power means for applying power to drive said drive shaft in a
second direction and thereby to exert force on said interfacing
means, in a power mode,
limiter means operatively connected to said drive shaft for
limiting the movement of said shaft in said first direction to its
reaching a first limit and for limiting the movement of said shaft
in said second direction to its reaching a second limit, and
direction reversal means connected to said braking means, said
power means, and said limiter means for automatically ceasing to
apply said braking means to said drive shaft at said first limit
and thereafter applying said power means thereto and for
automatically ceasing to apply said power means to said drive shaft
at said second limit and thereafter applying said braking means
thereto.
9. The device of claim 8 having means for adjusting said limiter
means to change the location of each of said limits.
10. The device of claim 8 having feedback means sensing the force
applied by said user to said drive shaft via said interfacing
means, said feedback means being connected to said power means and
to said braking means for regulating the driving force applied to
said shaft during said power mode and the braking force applied
during said braking mode.
11. The device of claim 10 having
braking programming means connected to said braking means for
changing the braking force during said braking mode according to a
predetermined program, and
power programming means connected to said power means for changing
the power applied to said drive shaft during said power mode,
according to a predetermined program.
12. The device of claim 11 having feedback means connected to said
drive shaft for altering both said programming means during use
according to the force applied by the user to said drive shaft.
13. A proportional resistance exercise device, including in
combination:
a rotary drive shaft,
user interfacing means connected to said drive shaft in driving
relation thereto and through which the user applies force to rotate
said drive shaft in a first direction and which applies force to
act on the user in a second direction of rotation of said
shaft,
braking means for applying braking force to said drive shaft while
it is rotated in said first direction by user-exerted force on said
interfacing means, in a braking mode,
power means for applying power to rotate said drive shaft in said
second direction and thereby to exert force on said interfacing
means, in a power mode,
limiter means for limiting the rotation of said shaft in said first
direction to prevent rotation beyond a first limit and for limiting
the rotation of said shaft in said second direction to prevent
rotation beyond a second limit, and
direction reversal means for automatically ceasing to apply said
braking means to said drive shaft at said first limit and
immediately thereafter applying said power means thereto to move it
in said second direction and for automatically ceasing to apply
said power means to said drive shaft at said second limit and
immediately thereafter applying said braking means thereto while
enabling said shaft to rotate in said first direction.
14. The device of claim 13 having
braking programming means connected to said braking means for
changing the braking force during said braking mode according to a
predetermined program,
power programming means connected to said power means for changing
the power applied to said drive shaft during said power mode,
according to a predetermined program,
feedback means sensing the force applied by said user to said drive
shaft via said interfacing means, said feedback means being
connected to said power means and to said braking means for
regulating the driving force applied to said shaft during said
power mode and the braking force applied during said braking mode,
altering both said programming means during use according to the
force applied by the user to said drive shaft.
15. A proportioned resistance exercise servo system, including in
combination:
a rotary drive shaft,
user interfacing means connected to said drive shaft in driving
relation therewith, so that movement of the one results in movement
of the other,
position sensing means sensing the position of said drive
shaft,
powering means,
speed-reducing means connected to said powering means and connected
to said drive shaft for driving said shaft in a power mode,
braking means connected to said speed-reducing means for exerting a
braking force therethrough on said shaft in a braking mode,
mode reversal means connected to said position sensing means and to
said powering means and to said braking means for changing the
operation of said drive shaft from the power mode to the braking
mode at one position and for changing it from the braking mode to
the power mode at another position,
speed and direction sensing means connected to said speed reducing
means,
a speed and direction programmer connected to said mode reversing
means, and
comparing means for continuously comparing signals from said speed
and direction sensing means with signals from said speed and
direction programmer and connected to said power means and to said
braking means for changing instantaneously the power applied during
the power mode and to braking applied during the braking mode.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to improvements in
exercising apparatus. More particularly, it relates to a system
wherein the resistive force of the apparatus is proportioned to the
instantaneous capacity of the user and is presented to the user in
a reciprocating fashion with controlled acceleration and
deceleration and simultaneous display of performance
parameters.
The principle of progressive-resistance exercise, wherein the
induced demand on the human system is progressively increased as
that system, through natural physiological compensation, increases
its capacity to handle increased demands, has been known and relied
on to improve the strength, endurance, and flexibility of the human
system since the time of legendary Milo, who was said to have
introduced the principle by lifting a growing bull each day.
According to the legend, Milo's body compensated for the
progressively increasing demand placed upon it by the increasing
weight of the bull by increasing his strength accordingly.
Similarly, today's weightlifter progressively increases the weight
of the barbell he lifts, today's runner progressively increases his
distance and speed, and the patient in rehabilitation progressively
increases the range of movement of his damaged shoulder, each
manipulating his body's natural compensatory processes toward the
desired objective, increased strength, endurance, and flexibility,
respectively.
Since Milo's time, a variety of exercise devices has been
developed, each seeking to provide, in a more convenient
configuration than Milo's bull, a progressively increasable
exercise resistance, preferably also of sufficient versatility that
a variety of general and specialized exercises might be performed
on the same device. Barbells, dumbells, and weightpulley machines
are representative of such developments.
A significant disadvantage of these prior-art devices has been
that, although the resistance was adjustable from exercise to
exercise to compensate for variations in the capacity of the user,
once a specific resistance was chosen, it remained constant for
each of the immediately sequential repetitions of the exercise
performed. Thus, less than maximal demand was placed upon the
bodypart being exercised in all but the last performable
repetitions of the exercise. Better results would be obtained by an
exercise system that could progressively increase its resistance as
the body became stronger and, at the same time, change its
resistance to compensate for the variable, primarily decreasing
capacity of the user during the course of several sequential
repetitions, or several sequential sets of repetitions. Maximal
demand would be placed upon the bodypart being exercised during a
significantly increased proportion of the exercise time, and
exercise program efficiency, if not results as well, would be
significantly improved over what is realizable with fixed
resistance devices.
Fixed resistance devices suffer the further shortcoming of being
unable to compensate for variations in capacity existing during the
course of a full range of movement of a single repetition of an
exercise. It is common knowledge, for example, that during the
performance of the biceps curl, in which a weight is raised to the
shoulder about the axis of the elbow, it is characteristic of the
leverages involved that more load can be raised through certain
angles of this movement than others, that is, that one is stronger
at certain points in the movement than others. Thus, using a fixed
resistance device such as a dumbell for the movement, one
necessarily limits the magnitude of that resistance to the maximum
amount that can be moved at the weakest angle, and all other angles
are sub-maximally loaded. Again, better results would be obtained
by an exercise apparatus that could automatically vary the applied
exercise resistance as is appropriate to compensate for the
variations in capacity characteristic of human skeletal leverage
systems. Such apparatus would constitute a significant improvement
over existing fixed resistance approaches.
Mechanical exercise devices have been developed which provide a
varying resistance during the course of specific movements
according to a preset program establishing a specific proportion of
a fixed resistance as appropriate for each specific point in the
movement. The resistance at any single point, however, remains
fixed from repetition to repetition, and, therefore, although these
devices are an improvement over simple fixed resistance, they are
not as good as a device incorporating variable resistance within
each repetition, among repetitions and sets of repetitions, as well
as among exercises and exercise sessions.
The task of providing variable exercise resistance that would, even
approximately, compensate for so complexly varying a parameter as
the instantaneous capacity of the human system performing exercise
movements is clearly unobtainable except by servo system technology
incorporating a sensing of that instantaneous capacity as a control
means for the variable resistance.
The desired sort of variables resistance, herein termed
"proportioned" resistance, as this is most appropriately
descriptive of the technology involved, has been incorporated into
a variety of exercise apparatus of recent design and manufacture.
In these devices, proportioned resistance is conventionally
achieved as a by-product of regulated speed, and the regulated
speed is obtained through classical servo system means, wherein a
secondary feedback mechanism is employed to regulate the primary
powering or braking function. In one device, for example, a
centrifugally governed braking device regulates the speed of
rotation of an unwinding drum, around which is wrapped a cable to
which the user applies a pulling force to obtain exercise. The net
effect is that, once the device reaches regulated speed, the harder
the user pulls on the cable, the more resistance is afforded the
user by the device, and the exercise resistance is, therefore,
variable and is proportioned to the instantaneous capacity of the
user.
Yet, although existing proportioned resistance exercise devices do
provide the presumed optimum variable and progressive exercise
resistance via servo means, they are believed to be universally
lacking in one or more additional elements believed equally
essential components of an optimally integrated proportioned
resistance exercise system.
For one thing, proportioned resistance for exercise purposes is
most effectively provided in a reciprocating fashion such that
eccentric muscular contractions (as when a weight is lowered from
the shoulder in a biceps curl) and concentric contractions (as when
the weight is raised to the shoulder in the same exercise) are both
made against a proportioned resistance in a continuous alternating
sequence. The necessity of this operating characteristic derives
from the apparent physiological fact that significant muscle
recovery occurs in a very short period of relaxation (a few
seconds), and, assuming that the desired objective of an efficient
exercise system is to exhaust a muscle's capacity in the shortest
practical elapsed time, any allowed period of relaxation in an
exercise movement serves to diminish the cumulative exercise effect
of the present repetition upon subsequent ones. Also, while it
would seem possible and practical to devise a system that would
totally exhaust a muscle's capacity in a single, uni-directional
repitition, thereby eliminating the necessity of a reciprocating
action, this uni-directional approach is believed not to produce
optimum results.
Thus, to obtain a reciprocating operation characteristic, in
addition to a speed-regulating feedback mechanism to produce
proportioned resistance, the desired exercise system must
incorporate a second servo loop, wherein the immediate position of
the device respective to presettable limits designating a specific
desired range of movement and the immediate direction of movement
of the device combine to initiate an automatic reversal in that
direction of movement at the specific desired positions. Such an
automatic reversal mechanism not only provides the required
reciprocating action, but also does so without distracting the
concentration of the user upon his primary exercise purpose, the
importance of which will subsequently be outlined, as would occur
were the reversals controlled by the user himself, and without the
participation of an attendant, as might otherwise be necessary in a
physiotherapeutic situation.
As may already be apparent from the discussions above, the
described regulated-speed approach to providing a proportioned
exercise resistance suffers the imperfection of responding not to
the user's absolute instantaneous capacity, but rather, to his
apparent capacity, because the resistance is controlled by the
amount of force the user exerts upon the mechanism. It will be
recalled that the net characteristic operation of this indirect
approach is that the harder the user pulls on the apparatus, the
harder the apparatus pulls against him. Conversely, should the user
exercise with less than maximal effort, less than maximal opposing
resistance is afforded him by the device, and less than optimum
results are achieved. Thus, it is important that the user
concentrate as totally as is practical upon exerting maximal effort
throughout all exercise movements.
In order for the user to control adequately the intensity of his
effort, it is essential to the function of an optimized
proportioned resistance exercise servo system that a third servo
loop be incorporated, wherein the user himself as an integral
component is presented with a display of certain performance
parameters such as force, work, or power, in comparison to which he
manipulates the level of intensity of his immediate efforts, and
thereby the response of the total system, and the ultimate results
of his exercise endeavors. It is implicit here that such
manipulation might, in fact, be at some prescribed sub-maximal
level to achieve certain objectives such as increased endurance, or
at maximal level to achieve certain other objectives such as
increased strength.
In the performance of conventional fixed resistance exercise
movements, the subject maintains control of the movement
acceleration and deceleration rates at the points of reversal of
direction of movement and change between concentric and eccentric
muscular contractions by varying the intensity of the contractions
at these points. In an automatically reciprocating system such as
that described herein, however, the user cannot effectively control
these rates, which must be limited to avoid possible injury
resulting from the mechanical shock loads so imposed upon him by
the apparatus, without significantly diminishing the effectiveness
of the exercise movement. For example, in the performance of
several sequential and continuous biceps curl movements, at the
points of direction of movement reversal from eccentric to
concentric contractions, that is, at the "bottom" of the movement,
such an apparatus as that so far described would afford the user
essentially no resistance other than the inertia and friction
inherent therein, as the system would be in a transitional state at
this point wherein neither braking nor powering is being applied,
deceleration of the present direction and subsequent acceleration
in the opposite direction would be virtually instantaneous, and
potentially injurious mechanical shock loads would be imposed upon
the user. The same, but reciprocal, phenomenon would occur at the
"top" reversal point.
To limit these mechanical shocks, the user would be required to
reduce the intensity of the force he applies to the device to some
sub-maximal level. Since this is contrary to the design objectives
of an optimized proportioned resistance exercise servo system, a
fourth servo loop must be incorporated, wherein the rates of
deceleration and acceleration of the system at the direction of
movement reversal points is sensed and compared to desired rates,
and the rates themselves are thereby controlled through the
appropriate application of compensatory powering or braking within
the system during the transitional periods.
Therefore, among the objects of the present invention are the
provisions of an exercise servo system wherein:
a. A variable exercise resistance is provided that is proportioned
to the apparent instantaneous capacity of the user via feedback
regulated speed control means;
b. This proportioned exercise resistance is provided during both
eccentric and concentric muscular contractions with controlled
relaxation periods in a continuous automatic reciprocating fashion
over an adjustable range of movement;
c. Performance feedback is provided to the user indicating the
intensity of his efforts and allowing his accurate manipulation
thereof; and
d. Rates of acceleration and deceleration at points of reversal or
direction of movement are controlled independent of the force
loading of the system.
These objects are accomplished through servo system techniques
employing automatic sensing and feedback control of system motion
parameters, namely, direction, position, speed, and force.
SUMMARY OF THE INVENTION
To obtain exercise from a system of the present invention, the user
attaches himself and applies force to an interfacing means. For
example, the interfacing means may be a bar, to the ends of which
are affixed one end of each of two cables, the other ends of which
are wrapped around two drums spaced the length of the exercise bar
apart and mounted upon a single driveshaft. It should be understood
here that alternative interfacing means of force transmission such
as levers, etc., are equally suited to the purpose of translating
exercise movements into system drive shaft rotation; the
bar-cable-drum approach is cited for its similarity to conventional
barbell fixed-resistance exercise methodology.
The system drive shaft to which the user applies force via this
interfacing means, is itself attached to a powering and a braking
means, alternately operated in powering and braking modes, with
feedback speed regulation, over a preset range of number of
driveshaft revolutions, and consequent length of cable travel and
range of exercise movement.
Thus, for example, in performance of the standard barbell curl, as
the user raises the bar to his shoulders, the cable unwinds from
around the drum and turns the driveshaft, to which, during this
concentric contraction, a braking device provides a proportioned
resistance via feedback speed regulation means. At the top of the
movement, that is, when the user has raised the bar to his
shoulders, the system applies increased braking to halt the upward
movement of the bar at a controlled deceleration rate, and then
switches to a powered mode with controlled acceleration and
feedback regulated speed, rewinding the cable on the drum against
the resistance of the user's eccentric contractions, until the
bottom of the movement is reached. At this point, again with
controlled deceleration and acceleration, the system reverses again
into the braking mode, and the cycle is repeated for the desired
number of repetitions to obtain the specific exercise
objective.
Throughout the above movements, or preferably at the end of each
repetition or half-repetition, selected exercise parameters such as
force, work, power, speed, and/or time may be displayed to the user
such that he may accordingly control the rate and intensity of his
exercise efforts.
Thus the system provides a proportioned exercise resistance through
feedback regulated speed control over a preset (adjustable) range
of movement in an automatic reciprocating fashion with controlled
acceleration and deceleration at points of direction of movement
reversal with performance feedback to the user.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a functional block diagram of a proportional resistance
exercise servo system embodying the principles of the invention.
Arrows in solid lines indicate the direction of force flow and
arrows in broken lines indicate the direction of signal flow.
FIG. 2 is a view in elevation of a preferred embodiment of a
proportioned resistance exercise servo system incorporating the
system of FIG. 1.
FIG. 3 is an enlarged view in elevation of a portion of FIG. 2
showing in more detail the powering-braking-sensing module.
FIG. 4 is a view in section along the line 4--4 showing the disc of
the optical tachometer.
FIG. 5 is an enlarged elevational view in detail of the control box
and performance display of FIG. 2.
FIG. 6 is a circuit diagram, part elemental and partly block of the
position sensing and mode reversal portions of the system of FIG.
2.
FIG. 7 is a functional schematic, largely block-type, diagram of a
speed and direction programmer used in the device of FIG. 2.
FIG. 8 is a simplified schematic diagram of the proportional
braking system of the FIG. 2 device.
FIG. 9 is a functional schematic diagram of an accumulative work
performance display, forming a part of the FIG. 2 device.
DESCRIPTION OF A PREFERRED EMBODIMENT
FIG. 1 shows a functional diagram of a proportioned resistance
exercise servo system embodying the principles of the invention.
The integrated feedback loops include the user himself and provide
a controlled exercise resistance in proportion to the amount of
force exerted by the user. This proportioned resistance is provided
over a selected range of movement in a reciprocating fashion, that
is, both through concentric and eccentric contractions of the body
part being exercised, with controlled acceleration and deceleration
at points of direction of movement reversal, and simultaneous
display of performance parameters.
A user 10 is coupled via a user interfacing means 11 (such as a
lever arm or a bar attached to a cable and drum) to a driveshaft
12. Also attached to the driveshaft 12 is a position sensing means
13, for example, limit switches, an optical encoder, or a
potentiometer. Electrical signals from the position sensing means
13 are read by mode reversal circuitry 14 as to appropriate
direction of rotation of the driveshaft 12. For example, assuming
that the driveshaft 12 has rotated clockwise to the limit preset in
the mode reversal circuitry 14, this fact is indicated electrically
by the position sensing means 13 and the mode reversal circuitry 14
then sends an electrical signal to a speed and direction programmar
15 to initiate counterclockwise rotation of the driveshaft 12,
until the preset limit in that direction had been reached, at which
point, the direction of driveshaft 12 rotation is again reversed,
providing the settable reciprocating motion characteristic of the
system. Thus the speed and direction programmer 15 serves as a
command for direction of rotation of the driveshaft 12. The speed
and direction programmer 15 combines this mode of operation command
with a variable speed program contained within its electronic
memory (or externally introduced) to control acceleration,
deceleration and speed variables.
The combined speed and direction signals thus produced by the speed
and direction programmer 15 are sent on as reference signals to a
comparator 16. The comparator 16 compares these reference signals
from the speed and direction programmer 15 with electrical signals
from a speed and direction sensing means 17, which may, if desired
be coupled to the system driveshaft 12 via a speed reducer 18, and
generates error signals in proportion to any difference between
actual system speed and direction of rotation and the electrical
"instructions" of the speed and direction programmer 15.
The error signals from the comparator 16 serve as commands for the
powering means 19, such as an electric servomotor, and braking
means 20, such as an electromagnetic brake, to initiate the
appropriate compensatory action, that is, via intermediate
transmission components, namely, the speed reducer 18, as required,
such as a gearbox, belt and pulley, or chain and sprocket drive, to
apply to the driveshaft 12 powering and/or braking forces of the
appropriate magnitude and direction to correct for speed and
direction of rotation errors and thereby maintain the total system
in equilibrium. Thus, proportioned resistance is provided to the
user 10, as the system speed is feedback regulated and therefore
instantaneously responsive to varying exercise force applied to the
driveshaft 12 during both concentric and eccentric muscular
contractions. Although the speed and direction sensing means 17 is
shown in this functional diagram coupled to the speed reducer 18,
it might just as feasibly be coupled to other system components
such as the powering means 19, braking means 20, or the driveshaft
12.
Completing the primary system servo loop so far described is a
performance display means 21, wherein the energy either supplied or
dissipated in the above compensatory process is translated into an
appropriate display of force, work, and/or power. This serves as
feedback to the user of the results of his exercise efforts, and
might be presented on cathode ray, matrix, analog, digital, or
printout display, as appropriate for specific performance
objectives. These performance measurement parameters might also be
recorded and stored for subsequent utilization in progress
assessment.
The performance display means 21 is shown in this diagram as
coupled to the driveshaft 12 via a torque sensing means 22, but it
might just as suitably be coupled also to the speed reducer 18 or
to the powering means 19 or to the braking means 20. Clearly,
measurement and display of complex performance parameters such as
power of the user would require integration of inputs from several
system components, including the torque sensing means 22, the
position sensing means 13, and the speed and direction sensing
means 17, as well as independent external sources such as a time
clock.
It should be noted that although the general frame of reference of
the above description of the functional diagram presented in FIG. 1
has been electrical in nature, forces and signals of mechanical
and/or hydraulic (fluidic) form might as effectively be utilized
throughout, or in combination, as required to optimally perform the
functions described herein. Note also that the arrows in solid
lines show the directions of force flow, while the arrows in broken
lines show the directions of signal flow.
FIG. 2 shows a preferred embodiment of a proportioned resistance
exercise servo system incorporating the principles and functions
outlined in the more generalized functional diagram of FIG. 1.
Here, an exercise bar 30, a pair of bearings 31, a pair of cables
32, and a pair of drums 33 comprise the interfacing means 11
between the user 10 (who stands on a platform 34 and applies force
to the exercise bar 30) and the system's driveshaft 35, a specific
embodiment of the driveshaft 12. The driveshaft 35 is supported by
and is free to rotate within a pair of pillow blocks 36.
The driveshaft 35 is coupled to a gearbox 37, which performs the
speed reduction and torque increasing function of the speed reducer
18. Also coupled to the gearbox 37 are a multi-turn potentiometer
38, which is used as the position sensing means 13, a permanent
magnet servo motor 39, which is used as both the powering means 19
and the braking means 20, a tachometer/generator 40, and, contained
within the motor mounting flange, an optical tachometer 41, which
corresponds to the member 22 in FIG. 1 and is more clearly shown in
a subsequent figure, used to supply speed sensing as input to a
performance display 42, corresponding to the member 21 in FIG.
1.
Also shown is a control box 43 which contains control, regulation,
and power supply circuitry to fulfill mode reversal, speed and
direction programming, comparator, and performance parameter
integration functional requirements (of elements 14, 15, 16, and 17
in FIG. 1), and the circuit to the box 43 is detailed in subsequent
figures and descriptions. Powering, braking, sensing, and display
components are connected to the control box with electrical cables
44.
Proper and effective utilization of the apparatus will be apparent
to those skilled in the art who study this figure and prior and
subsequent figures and descriptions contained herein. The specific
apparatus described is but one of numerous practical embodiments of
the four servo functions considered essential to an optimized
exercise servo system, namely, proportioned resistance, automatic
reciprocating action, controlled acceleration and deceleration, and
performance feedback. Certain of the specific approaches contained
in this apparatus are believed to be unique in the state of the
art, and these approaches, particularly, are further detailed in
this description of the preferred embodiment of the apparatus.
FIG. 3 shows in detail the system gearbox 37 and associated
components, comprising a powering-braking-sensing module. A
positive traction belt 45 is shown coupling the driveshaft 35 to
the multi-turn potentiometer 38. Also, the details of the optical
tachometer 41 are shown. A disc 46 is mounted upon a servomotor
shaft 47. Near the circumference of this disc 46 and concentric
about its axis of rotation are a number of suitably spaced holes
46a, as shown in FIG. 4. As the disc 46 rotates, these holes 46a
consecutively appear between a light source 48 and a photodetector
49. As the holes in the disc 46 pass between these components, a
series of pulses is generated by the photodetector 49 proportionate
in number to the amount of rotation of the servomotor shaft 47,
and, therefore, proportionate to the distance of travel of the
exercise bar 30. The frequency of these pulses is a measure of
system distance of movement as well as speed, and is used as one
parameter in the performance readout system outlined in subsequent
figures. The components shown in FIG. 3 comprise the complete
assemblage of powering, braking, and sensing functions of this
embodiment of my new proportioned resistance exercise servo system,
fulfilling all of these functional requirements herein considered
essential.
FIG. 5 shows in more detail the system control box 43 and the
performance display 42. Both would usually be located remote from
the remainder of the system but connected to it via electrical
cables 44. For example, the control box 43 may be placed to one
side of the user, such that he can conveniently make adjustments
between exercises, while the performance display 42 may be located
in front of him such that he can observe performance parameter
readout while exercising.
As shown here, the performance display 42 is configured so as to
present an accumulative measurement of amount of work done in
"scoreboard" fashion. Digital indicators 50 and 51 alternately
display and hold a numerical count proportional to the amount of
work done in the just-completed repetition. As shown in FIG. 5,
twenty-three units of work have been done in the previous
repetition, whereas none have been done in the current one. An
indicator 52 shows that 812 units of work have been done in this
"set" (several sequential repetitions) of the exercise. An
indicator 53 displays the same parameter for several sequential
"sets", and an indicator 54 shows the same for several sequential
exercises.
Push buttons 52a, 53a, and 54a are provided on the control box 43
for the user to reset the three digital indicators 52, 53, and 54
at the end of each set, exercise, and session, respectively. The
"rep" digital indicators 50 and 51 reset automatically at the
beginning of alternate repetitions of an exercise.
On the control box 43, digital indicators 56, 57, and 58 display
uppermost point of reversal, present position, and lowermost point
of reversal, respectively. Thus, after once establishing an optimum
range of movement for a particular exercise, the user may
repeatably "dial" the appropriate settings into the system at
subsequent exercise sessions. This is accomplished with range
setting potentiometers 59 and 60. A master switch 61 connects and
disconnects the system to the power line. The speed of upward
movement of the exercise bar 30, its downward movement, and its
rate of acceleration and deceleration at points of direction
reversal are controlled respectively with speed and acceleration
settings potentiometers 62, 63, and 64, respectively. Additional
controls and indicators may be included as required, such as force
limitation, elapsed time, speed and range of movement programming,
etc., or, controls may be eliminated through the incorporation of
automatic programming means, such as magnetic cards, computer
memory, etc., if desired.
FIG. 6 shows a functional schematic diagram of position sensing and
mode reversal circuitry. The multi-turn potentiometer 38 is
attached to the system drive shaft 35, and rotates with it; its
setting is therefore dependent upon the position of the exercise
bar 30, and it serves as a position sensing means in the
system.
The output of this potentiometer 38 is compared to the outputs of
two reference potentiometers, the range setting potentiometers 59
and 60, by an upper limit comparator 65 and a lower limit
comparator 66, respectively, both standard voltage comparator
units. Thus, as the exercise bar 30 approaches its preset upper
limit, the upper limit comparator 65 sends an electrical signal to
a switching logic circuit 67, which initiates through a memory
element 68 a command at a mode reversal output 69 for reversal of
direction of driveshaft rotation. The same thing occurs via the
lower limit comparator 66 as the exercise bar 30 approaches its
preset lower limit, and the required automatic reciprocating
movement of the exercise bar 30 is thereby accomplished.
The switching logic 67 is configured by well-known means such that
the position sensing potentiometer 38 setting must be higher than
both the upper and lower limits before reversal into a downward
movement of the bar 30 is initiated, as it is possible to set the
lower limit above the upper limit, which case must yield no mode
reversal. The memory element 68 holds the system in one of the two
operating modes (upward or downward movement of the exercise bar
30) until the automatic mode reversal command is received from the
switching logic 67.
The mode reversal output 69 is connected to the input of a speed
and direction programmer, diagrammed in FIG. 7. The implementation
of the details of these circuits is well known among those skilled
in the art of electronic technology.
FIG. 7 is a functional schematic diagram of a speed and direction
programmer, including circuitry for control of acceleration and
deceleration rates. In this particular example, the desired
"program" is to alternately rotate the system driveshaft 35
clockwise and counterclockwise at independently adjustable speeds
in each direction with a single adjustable linear
deceleration/acceleration rate at points of direction of rotation
reversal.
This is accomplished with a latching digital up/down counter 70, an
up/down toggle input 69a of which is continuous with the mode
reversal output 69 of the mode reversal circuitry of FIG. 5. The
up/down counter 70 either counts up to a maximum or down to a
minimum depending upon the signal at its toggle input 69a at a rate
established by the R-C time constant of the
acceleration-deceleration setting potentiometer 64 and a timing
capacitor 71, which are components of a free-running multivibrator
72. Thus, when the mode-reversal circuitry so commands, the output
of a digital-to-analog converter 73, which is connected to, and
performs an integration function upon, the several outputs of the
up/down counter 70, advances gradually from a maximum value to a
minimum value, or vice-versa, and holds that value until another
reversal is initiated.
The output of the digital-to-analog converter 73 is clamped by
clamping diodes 74 and 74a at specific values set by the upward and
downward (clockwise and counterclockwise) speed setting
potentiometers 62 and 63, which are independently adjustable. These
speed setting potentiometers thus limit the excursion of voltage
output of the digital-to-analog converter 73 about a voltage midway
between maximum and minimum, which point is considered "null", that
is, a command established such that the system does not move in
either direction.
Thus, a speed and direction output 75 makes electrical excursions
about a "null" value at an adjustable rate between adjustable
limits, serving as a combined speed and direction command for
system operation. This output is used as a reference signal against
which the output of the system tachometer generator 40 (speed and
direction sensing means) is compared by the system comparator 16,
which initiates the appropriate system compensatory response
(powering or braking) to maintain equilibrium. The implementation
of the details of this circuitry is well known among those skilled
in the art.
FIG. 8 shows a simplified schematic diagram of the utilization of a
generator as a proportioned braking means. As was noted in the
description of FIG. 2, above, this embodiment of the invention
utilizes a single permanent-magnet type servomotor as both a
powering and a braking means. Since a very particular sort of
braking, namely, proportioned braking, is required in a
Proportioned Resistance Exercise Servo System, the specific
approach, namely, feedback shunt regulation, is outlined in FIG.
8.
Here, the servomotor 39 and the tachometer/generator 40 are coupled
to the same output shaft 47. As rotating force is applied to the
shaft 47, presumably, in this case, by the user 10 in his exercise
efforts, both the servomotor 39 and the tachometer/generator 40
behave as generators. As the speed of rotation of the shaft 47
increases, the voltage output of the tachometer/generator 40 also
increases, approaching a value established in a voltage reference
element 76, the functional analog of the output of the speed and
direction programmer outlined in FIG. 7. As this voltage reference
value is approached, current begins to flow through a series
resistance 77 and a shunt element 78, in this case,
Darlington-connected power transistors. The shunt element 78 shunts
away the current being generated by the servomotor 39 in
proportion, therefore, to the speed of rotation of the shaft 47,
and a proportioned dynamic braking feedback speed regulation is
thereby accomplished. The regulation speed may be adjusted by
varying the voltage reference value of the voltage reference
element 76. The implementation of the details of this circuitry is
well known to those skilled in the art.
FIG. 9 shows a functional schematic diagram of an accumulative work
performance display incorporated in the subject exercise servo
system to provide to the user 10 feedback information regarding the
results of his exercise efforts, such that he may manipulate those
efforts in the utilization of the apparatus toward desired
objectives. In this particular embodiment, the torque sensing means
is the DC permanent-magnet servomotor 39 itself, as both when
behaving as a powering device (motor) and a braking device
(generator), the torque is proportional to the amount of current
flowing through the servomotor 39. This current is measured as a
voltage drop across a current sensing resistor 79 in both the
powering and braking modes, as the servomotor 39 is being either
proportionately driven by conventional feedback regulated powering
circuitry 80 or proportionately shunted (as outlined in FIG. 8) by
feedback regulated braking circuitry 80. It should be noted here
that, as indicated in the description of FIG. 1, effective
measurement of work performance is not contingent upon this
specific approach to torque sensing; a variety of means such as
strain gauges, spring deflection devices, etc., might suitably
substitute for the direct current measurement approach outlined
here.
The electrical measurement of system torque thus obtained is
integrated with a measurement of distance of system movement in the
following manner: a multivibrator 81 generates a continuous and
constant frequency of pulses as long as its oscillations are not
inhibited by a comparator 82. These pulses are counted, divided,
and displayed by the digital indicator 52. It should be noted that
in the interest of simplicity, only one of the indicators shown in
FIG. 4 is shown here, in this case the "set" indicator. All of the
several indicators display appropriate combinations of counts of
the output of the same multivibrator 81.
In addition to being counted by the indicator 52 the output pulses
of the multivibrator 81 are also counted by a digital counter 83,
the several outputs of which are converted to an analog voltage by
a digital-to-analog converter 84, that is, an analog voltage is
presented to the comparator 82 that is proportional to the number
of pulses generated by the multivibrator 81. The multivibrator 81
pulses are counted, accumulated, and displayed by the indicator 52
until an analog voltage is developed at the output of the digital
to analog converter 84 that is equal to the voltage developed
across the current sensing resistor 79, at which time the
comparator 82 output changes state and inhibits further oscillation
of the multivibrator 81. Thus, a display appears on the indicator
52 that is proportional to the system torque, or the force applied
by the user.
In the description of FIG. 3, an optical tachometer 41 was
described having a light source 48, a disc 46 rotating on the motor
shaft 47, and a photodetector 49, in this case a phototransistor.
The photodetector 49 develops pulses across a series resistance 85
that are proportional in number to the distance of movement of the
exercise bar. These pulses are used to "reset" the digital counter
83, periodically "enabling" the inhibited multivibrator 81 for
another series of counts as outlined above. Thus, during each
specific small increment of movement of the exercise bar, the force
applied to the bar (system torque) is measured once, and the
product of force and distance (work) is accumulatively displayed on
the indicator 52. The implementation of the details of this
circuitry is well known among those skilled in the art.
When the user desires to perform a standard barbell curl, he turns
on the master switch 61 and preselects the desired range of
movement by adjusting the range setting potentiometers 59 and 60
while viewing the digital indicators 56 and 58 until these indicate
numerically the upper and lower reversal points desired. He also
preselects the desired speed of movement and acceleration and
deceleration rates by adjusting the potentiometers 62, 63 and 64,
as required. Assuming that this is the first of several sets and
exercises to be performed in the exercise session, the user resets
all of the digital performance indicators 50, 51, 52, 53 and 54 by
depressing the pushbuttons 52a, 53a, and 54a. Having made these
required settings, the user stands erect upon the platform 34,
grips the exercise bar 30 with hands spaced equidistant from its
center, and begins the exercise by applying concentric contractions
of the biceps muscles to raise the exercise bar 30 to shoulder
level. (It is assumed here that, at the start of the exercise, the
exercise bar 30 rests at some point lower than shoulder level, or
the upper limit set point, as, during the course of adjustment of
the range setting potentiometers 59 and 60 previous to beginning
the exercise, should the exercise bar 30 have rested above the
upper limit set point, power would have been applied through the
system to bring the exercise bar 30 below that point.)
The force of the concentric contractions of the user's biceps
muscles is transmitted to the cables 32 through the bearings 31
attached to the exercise bar 30. This force applied to the cables
32 unwinds them from the drums 33, applying rotational torque to
the system driveshaft 35 and therefore simultaneously the servo
motor 39, the tachometer-generator 40, the optical tachometer 41,
and the position sensing potentiometer 38 via the gearbox 37, and
causing all of these components to rotate.
When the force applied by the user is sufficient to cause these
system components to rotate at the preselected speed, the voltage
output of the tachometer-generator 40 turns on the shunt element 78
across the output of the servomotor 39, now behaving as a
generator, thereby applying a dynamic braking force in oposition to
and in proportion to the force applied by the user, such that the
preselected speed is not exceeded. Thus, a proportioned exercise
resistance is provided against the concentric contractions of the
user's biceps muscles as he raises the exercise bar 30 toward his
shoulders and the upper limit setpoint at the preset regulation
speed.
While the user is raising the exercise bar 30 to shoulder level,
the performance display 42 accumulates counts on the digital
indicators 50, 52, 53 and 54, but not on the digital indicator 51
which is in a "hold" mode, at a rate proportionate to the product
of distance of movement and applied force, that is, in proportion
to the amount of work being done by the user. To monitor his
instantaneous efforts, the user observes the rate of count
accumulation, these counts being derived through the digital
integration of electrical signals from the current sensing resistor
79, which are proportional to the applied force, and the optical
tachometer 41, which are proportional to the distance of
movement.
When the user has moved the exercise bar 30 to the upper limit set
point, which presumably coincides with shoulder level, the voltage
output of the position sensing potentiometer 38 just exceeds that
of the upper limit range setting potentiometer 59, and this
difference is sensed by the upper limit comparator 65, which via
the switching logic 67 and memory element 68 causes the up-down
counter 70 to count down at a rate preset by the acceleration
setting potentiometer 64. The digital-to-analog converter 73
converts the output of the descending up-down counter 70 to a
descending analog voltage, the voltage reference 76 in the braking
circuitry.
Assuming that the system driveshaft 35 is still rotating at the
preset regulation speed, it can be seen that the difference between
the output of the tachometer-generator 40 and the voltage reference
76 thus becomes progressively larger, turning on the shunt element
78 more strongly and increasing the dynamic braking forces so
applied to gradually, at the rate preset in the
acceleration-deceleration rate setting potentiometer 64, declerate
the upward movement of the exercise bar 30.
As the exercise bar 30 and thus the driveshaft 35 and other system
rotating components decelerate in the present direction, it can be
seen that a reduced speed in the present direction is reached,
below which shunted current braking becomes ineffectual. At this
point, signaled by a consequent increasing difference between the
outputs of the tachometer-generator 40 and the digital-to-analog
converter 73, the system comparator 16 applies power to the servo
motor 39 to cause it to continue to apply gradually increasing
braking forces in a "plugging" mode until rotation in the present
direction ceases, and then to gradually increase speed of rotation
in the opposite direction until the limit preset with the downward
speed setting potentionmeter 63 is achieved, at which speed the
output of the digital-to-analog converter 73 has ceased its
downward excursion and the system functions to maintain the output
of the tachometer-generator 40 at a constant level in the new
direction.
Thus, while the user's biceps muscles have continued to apply force
to the exercise bar 30 beyond the upper limit set point, the system
has "overpowered" him, gradually halting the upward movement of the
exercise bar 30, reversing its direction of movement, and gradually
increasing its rate of movement downward until the preset
regulation speed in that direction is achieved. In the downward
direction, proportioned power is continuously applied to the
servomotor 39, winding the cables 32 upon the drums 33 attached to
the driveshaft 35, and pulling the exercise bar 30 downward at
regulation speed against the forces of eccentric contractions of
the biceps muscles applied by the user in an upward direction. The
harder the user pulls against the downward movement of the exercise
bar 30, the more power is applied by the system to maintain preset
regulation speed, and thus a proportioned exercise resistance is
provided against the user's efforts.
During this downward movement, the user may monitor his efforts on
the performance display 42 upon which is presented a continuing
accumulation of the amount of work being done on all but the one
digital indicator 51.
When the exercise bar 30, now moving in a downward direction,
reaches the lower limit set point, previously set with the lower
limit range setting potentiometer 60, which presumably concides
with a point in the biceps curl movement at which the arms are
nearly fully extended downward, the voltage output of the position
sensing potentiometer 38 drops just below that of the lower limit
range setting potentiometer 60, and this difference is sensed by
the lower limit comparator 66, which, via the switching logic 67
and the memory element 68 causes the up-down counter 70 to count up
at the rate preset with the acceleration potentiometer 64, and the
digital-to-analog converter 73 converts the output of the ascending
up-down counter 70 to an ascending analog voltage, the voltage
reference for the system comprator 16. This process is identical to
that which previously occurred at the upper limit point of reversal
of direction of movement, except in reverse; that is, in proportion
to the force being applied by the user, when the exercise bar 30
reaches the lower limit point of reversal, power is gradually
removed and then braking is applied, first strongly, and then
gradually diminishing until the exercise bar 30 is again moving
upward at the preset regulation speed, thus effecting a re-reversal
of direction of movement with controlled deceleration in the
present downward direction and controlled acceleration in the new
(original, upward) direction.
Once the lower limit reversal has been completed, the system again
functions in the shunt regulation mode as outlined above, providing
a proportioned exercise resistance against the concentric
contractions of the user's biceps muscles as he exerts effort to
move the exercise bar 30 upward again toward the upper limit set
point. It may be seen, therefore, that the system operates in a
continuous reciprocating fashion between the upper and lower limit
set points as long as the user exerts, or is capable of exerting,
sufficient upward force on the exercise bar 30 to move the system
in the upward direction to the upper limit set point.
It will be recalled that during both the upward and downward
movements of the first repetition of the biceps curl described
above, a display of the amount of work being done has been
accumulating on all of the digital indicators 50, 52, 53 and 54 of
the performance display 42, but not on the digital indicator 51,
which has been on "hold", is reset to zero and "enabled", while the
other "rep" indicator is placed on "hold" for the duration of the
next complete repetition. At the present point, then, after the
completion of the first repetition, the digital indicator 50
displays the amount of work done in the first repetition, against
which the user may compare the amount of work he is doing in the
second repetition, which is now accumulating on the other "rep"
digital indicator 51. The other digital indicators 52, 53, and 54
continue to accumulate the sum of all repetitions.
At the end of the second repetition, the first "rep" digital
indicator 50 will reset to zero, "enable", and begin accumulating
the amount of work done in the third repetition, while the other
"Rep" digital indicator 51 will retain the amount of work done in
the second repetition for comparison purposes. Thus, the "rep"
digital indicators 50 and 51 alternately accumulate and hold a
display of the amount of work done in the present and previous
repetitions of the exercise, respectively, while the other digital
indicators 52, 53, and 54 accumulate and display the sum of the
amount of work done in all repetitions.
Assume that the user has established for himself the objective of
completing three sets of the biceps curl exercise at this session,
with a specific period of rest between sets, with maximal effort,
known from previous experience to yield a peak of about 100 "units"
of work in a single repetition, to be exerted in all repetitions,
and with repetitions to be continued in each set until exhaustion,
and with the overall goal of accumulating a total of 2000 "units"
of work for the exercise. During each repetition of the first set,
he observes the alternating rep displays and attempts to maximize
his effort such that each repetition's total exceeds 100 units, if
possible, or, at least, exceeds the previous repetition as total.
Muscle fatigue, of course, prohibits his accomplishing this in all
repetitions, and he might, for example, accumulate these totals for
the first set: 80, 88, 103, 92, 97, 66, 41, 38, 17, 10, 12, 8.
Thus, in the 12 sequential repetitions of the first set of biceps
curls, he has totaled 652 "units" of work, just under one-third of
his total objective for the exercise, and this total is displayed
on the "set", "exercise", and "session" digital indicators 52, 53,
and 54. During his rest period, he pushes the "set" display reset
pushbutton 55 on the control box 43 to reset the "set" digital
indicator 52 to zero (the "exercise" and "session" digital
indicators 53 and 54 retain the 652 count) and contemplates the
obvious implication of his first set performance namely, that if he
is to achieve the overall objective of a total of 2000 units, he
will have to try significantly harder in his second set than he did
in the first, as he knows from prior experience that the third set
will yield far less than one-third of the total for the exercise,
due to the limitations imposed by fatigue.
At the end of the second set, the "set" digital indicator 52 will
display his total for the second set only, while the "exercise" and
"session" digital indicators 53 and 54 will display the total of
both sets. Again, between sets, the user will reset the "set"
indicator 52 to zero. At the end of the third set, the "set"
digital indicator 52 will display his total for the third set only,
while the "exercise" and "session" digital indicators 53 and 54
will display the total for all sets.
Since at the end of the third set, the user will have completed all
desired sets of the barbell curl, he will "reset" both the "set"
and "exercise" digital indicators 52 and 53 in preparation for the
next exercise, possibly after recording his performance data on a
chart for future reference and progress assessment. It should be
noted here that other, or supplementary means of performance
parameter display and recording might be well suited for
application here. For example, a digital printer or computer memory
might record the totals for each repeition, set, exercise, and/or
session for reference and analysis. Thus, it may be seen that the
performance display 42 described herein serves simultaneously to
permit the user to analyze the results of his efforts and to
motivate himself toward the accomplishment of specific exercise
objectives. It should be noted here, however, that the objectives
cited are for example only; a variety of objectives are possible
with the system, including specific sub-maximal amounts of work per
repetition, specific or maximal totals for limited numbers of sets,
varying periods of rest between sets or repetitions, varying speeds
and ranges of movement, etc.
Let us now suppose that the user desires to perform the regular
knee-bend as his second and final exercise in this session. Having
previously determined the desired speed, acceleration, and range of
movement for this exercise, he adjusts the appropriate
potentiometers 59, 60, 62, 63, and 64 on the control box 43, stands
upon the platform 34, bends his knees, places the exercise bar 30
across his shoulders behind his neck, and, keeping his back as
straight as possible, straightens his legs to stand erect, exerting
an upward force on the exercise bar 30. In this exercise, the
system functions in the same manner as outlined for the barbell
curl, providing the appropriate amount of resistance throughout the
movement, with the upper reversal of movement occurring when the
body comes erect, and the lower reversal occurring when the thighs
are approximately parallel to the platform 34. Again, the user
observes the performance display 42 during the performance of the
exercise and adjusts his efforts toward certain desired objectives,
resetting the "set" digital indicator 52 between sets.
At the end of his several sets of knee-bends, the user may observe
and record his cumulative work total for this exercise on the
"exercise" digital indicator 53, as well as for both his curls and
knee-bends on the "session" digital indicator 54. After "resetting"
the "set" and "exercise" digital indicators 52 and 53, the user
might go on to perform any number of desired exercises in the
session in similar fashion. The "session" digital indicator 54
might be reset to accumulate the amount of work done in any
sequential group of exercises, "cancelling out" those previously
completed. Clearly, alternative performance indicating systems
might be devised, for example, to accommodate several users using a
single apparatus simultaneously, as it is common practice for two
or more "training partners" to utilize the same apparatus, one
exercising while the other is resting.
The specific exercises described above are cited for example only;
the apparatus is well suited to a variety of common exercises such
as standing press, rowing, bench press, calf raises, etc. as well
as highly specialized exercises, some of which require additional
or alternate user-interfacing means.
To those skilled in the art to which this invention relates, many
changes in construction and widely differing embodiments and
applications of the invention will suggest themselves without
departing from the spirit and scope of the invention. The
disclosures and the description herein are purely illustrative and
are not intended to be in any sense limiting.
* * * * *