U.S. patent application number 14/210945 was filed with the patent office on 2014-09-18 for motorless treadmill with large flywheel.
This patent application is currently assigned to Global Fitness Products, LLC. The applicant listed for this patent is Global Fitness Products, LLC. Invention is credited to Charles P. Kennedy.
Application Number | 20140274578 14/210945 |
Document ID | / |
Family ID | 51529702 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140274578 |
Kind Code |
A1 |
Kennedy; Charles P. |
September 18, 2014 |
Motorless Treadmill with Large Flywheel
Abstract
A motorless exercise treadmill has a flywheel of 7 to 10 inches
radius, weighing 40 to 60 pounds. The flywheel provides a fluid
motion for the belt when the brake system is engaged and smooth
transition through increasing or decreasing speeds. Inclination of
the treadmill is fixed at 9 to 20 degrees, which accommodates the
large size of the flywheel. Handle and other attachments of
different designs are provided so the user can exercise in various
positions with various resistance levels for developing specific
leg, core, arm and other muscles, not normally achievable on a
treadmill.
Inventors: |
Kennedy; Charles P.; (Moon,
PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Global Fitness Products, LLC |
Moon |
PA |
US |
|
|
Assignee: |
Global Fitness Products,
LLC
Moon
PA
|
Family ID: |
51529702 |
Appl. No.: |
14/210945 |
Filed: |
March 14, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61782998 |
Mar 14, 2013 |
|
|
|
61858854 |
Jul 26, 2013 |
|
|
|
Current U.S.
Class: |
482/54 |
Current CPC
Class: |
A63B 21/015 20130101;
A63B 22/02 20130101; A63B 21/4039 20151001; A63B 21/225 20130101;
A63B 69/345 20130101; A63B 69/0057 20130101; A63B 21/4033 20151001;
A63B 23/047 20130101 |
Class at
Publication: |
482/54 |
International
Class: |
A63B 22/02 20060101
A63B022/02; A63B 21/22 20060101 A63B021/22 |
Claims
1. A motorless treadmill comprising (a) a frame, (b) a high front
roller and a low rear roller held by said frame, (c) a continuous
treadmill belt in contact with said front and rear rollers, said
treadmill belt having an outer surface and an inner surface, said
inner surface in contact with said rollers, said rollers and said
treadmill belt defining an exercise surface inclined at a fixed
angle of 9 to 20 degrees from said low rear roller to said high
front roller, (d) a flywheel fixed to said front roller, said
flywheel having a radius of 7 to 10 inches and a perimeter weighted
mass of 40 to 60 pounds.
2. The motorless treadmill of claim 1 wherein said fixed angle of
inclination is in the range of 11 to 13 degrees.
3. The motorless treadmill of claim 1 including a brake operable by
a user on said treadmill, said brake including a brake pad for
contacting said flywheel.
4. The motorless treadmill of claim 1 wherein said mass of said
flywheel is 45 to 55 pounds,
5. The motorless treadmill of claim 1 wherein said flywheel
includes a brake for said flywheel, said brake including a brake
pad adapted to contact said flywheel and a screw adapted to move
said brake pad.
6. The motorless treadmill of claim 1 wherein said flywheel is
directly attached to said front roller so as to rotate with said
front roller.
7. The motorless treadmill of claim 1 wherein said flywheel has two
parts, said parts attached to opposite ends of the front roller,
each part thereof having a radius of at least 7 inches, said parts
each having a mass of at least 20 pounds.
8. The motorless treadmill of claim 1 including an elongated socket
mounted on the front of said frame, said elongated socket adapted
to receive and fix a shaft of one or more interchangeable accessory
positioners.
9. The motorless treadmill of claim 1 wherein said frame includes
stationary shoulders next to said exercise surface.
10. A motorless treadmill comprising (a) a treadmill frame
including a front end and a rear end, said frame including a
treadmill belt, a front roller on said front end, and a rear roller
on said rear end, said front and rear rollers for enabling said
treadmill belt to turn, said treadmill frame including at least one
front support member fixedly elevating said front roller at an
angle of 9 to 20 degrees from said rear roller, (b) an elongate
socket fixed to the front end of said frame, said socket being
adapted to receive and fix a shaft of one or more interchangeable
handles for grasping by a user to assume a variety of positions and
apply a variety of muscles by a user, and (c) a perimeter weighted
flywheel fixed to said front roller, said perimeter weighted
flywheel having a mass of 40 to 60 pounds.
11. The motorless treadmill of claim 10 fixed at an incline between
11 and 13 degrees and wherein said flywheel has a radius 7 to 10
inches.
12. The motorless treadmill of claim 10 including side rails
mounted on the sides of said frame.
13. The motorless treadmill of claim 10 including a screw operated
brake pad for said flywheel.
14. A motorless treadmill having a fixed inclination of 9 to 20
degrees comprising (a) a frame including a socket for receiving an
accessory shaft, and (b) a plurality of accessory shafts adapted to
fit securely in said socket and having handles deployed in various
orientations.
15. The motorless treadmill of claim 14 including a flywheel
adapted to provide inertial energy to said treadmill, said flywheel
having a radius of 7 to 10 inches and a perimeter weighted mass of
40 to 60 pounds.
16. The motorless treadmill of claim 14 wherein an accessory shaft
(b) has an arm rest.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the full benefit of U.S. Provisional
Application 61/782,998 filed Mar. 14, 2013 and U.S. Provisional
Application 61/858,854 filed Jul. 26, 2013, both of which are
hereby incorporated herein by reference in their entireties.
TECHNICAL FIELD
[0002] The invention relates to exercise treadmills. In particular,
it relates to motorless treadmills--that is, treadmills powered by
the user. Handle and other attachments of different designs are
provided so the user can exercise in various positions with various
resistance levels for developing specific leg, core, arm and other
muscles. A large flywheel of a particular design is arranged to
provide a fluid motion for the belt when the brake system is
engaged and smooth transition through increasing or decreasing
speeds. Inclination of the treadmill is fixed.
BACKGROUND OF THE INVENTION
[0003] Generally, treadmills are powered by a motor and are used
mainly for aerobic (cardiac) exercise such as walking and running,
but provide little or no possibility of simultaneous specific or
varied muscle strengthening regimes with resistance training. Some
elliptical machines are designed to strengthen leg muscles, but
must be further equipped if they are to exercise the arms, upper
body and other muscles. Equipping an exercise machine of any kind
with a motor adds significant cost, operating expense, liability,
and limited mobility. The art is in need of an affordable highly
versatile exercise machine.
SUMMARY OF THE INVENTION
[0004] The present invention is a manually powered inclined
treadmill with various levels of resistance. The conventional motor
is replaced with a large heavy weighted flywheel, obviating the
expense and maintenance necessitated by a motor. The motor is
replaced with a 40-60 pound flywheel having a large diameter and
other attributes explained below, which captures the energy of the
belt motion. The flywheel keeps the belt in motion, and maintains a
fluid motion through transitions of resistance and speed. A brake
effect may be applied to the flywheel at the discretion of the
user. The brake system when applied creates resistance on the
flywheel, enabling the user to enhance a strength profile. The
resistance to the flywheel is applied incrementally, affording the
user with a wide range of resistance levels. In order to generate
the desired moment of inertia, the large diameter flywheel must
contain a high percentage of its mass, or weight, toward its outer
edge. Since the user must use muscle power entirely to move the
inclined belt and the treadmill can have various levels of
resistance applied, he or she simulates actual incline climbing
more effectively than when the belt is powered by a motor, burning
more calories and effecting greater muscle stimulation.
[0005] The motorless, inclined treadmill is designed to be a
crossover between (that is, to incorporate the benefits of) an
inclined treadmill and an elliptical. It offers the cardio benefits
of a treadmill motion with the muscle stimulation of elliptical,
while enabling variable resistance levels and facilitating arm,
shoulder and upper body muscle development as well as providing
significant leg muscle challenges. It is equipped with multiple
vertical and horizontal hand stations so the user can position
himself or herself into various postures simulating an elliptical
motion, a football sled, or other regimes not readily available
with other types of exercise machines.
[0006] Solidly attached to the frame of my treadmill is an
elongated socket adapted to receive elongated stems or shafts for a
variety of handles and pressure surfaces which may be used at
different heights and with a wide variety of speed and
resistance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view showing an exerciser on the
treadmill using an arm rest attachment.
[0008] FIG. 2 illustrates an exercise position on the treadmill
different from that of FIG. 1, employing a different front
attachment.
[0009] FIG. 3 shows the treadmill equipped for using the shoulders
to push.
[0010] FIG. 4 shows a front attachment that facilitates a forward
leaning position, enabling a longer stride.
[0011] FIG. 5 shows the braking device.
[0012] FIG. 6 is a graph showing speed change of the perimeter
weighted treadmill over a single stride at different speeds and at
various inclinations.
[0013] FIG. 7 is a graph showing force required to maintain a
constant speed at various inclinations.
[0014] FIGS. 8a to 8f illustrate the treadmill with separated
attachments.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Referring now to FIG. 1, the treadmill is seen to have a
continuous treadmill belt 1 forming a treadmill exercise surface 2
and supported by front roller 3 and back roller 4, which are
mounted in frame 5. Exercise surface 2 of treadmill belt 1 rides on
a support surface (not shown) as is known in the art. Frame 5 rests
on feet 14. Attachment support socket 6 is fixed to the front of
frame 5. Attachment socket 6 is hollow and may be cylindrical or
define a square or other cross section in order to receive snugly
the stem 7 of an accessory positioner 8. Accessory positioner 8 has
a particular shape and configuration, in this case including an arm
rest portion 15, but other, interchangeable, accessory positioners
may have different shapes and configuration as will be explained
below. Attachment socket 6 is provided with holes 9 so that pins 10
can pass through them and through complementary holes 11 on stem 7
and similar stems for other accessory positioners. As depicted in
FIG. 1, user 16 is resting her arms on arm rest portion 15 of
accessory positioner 8 and grasps handles 17. She is thus able to
exert significant forward thrust on the treadmill exercise surface
2. Front roller 3 is turned by the treadmill belt 1 and, since
flywheel 12 is fixed to front roller 3, the flywheel 12 will rotate
in a clockwise direction, as depicted. The significant moment of
inertia of the perimeter weighted flywheel soon assures a smooth
continuous movement of the treadmill belt 1. User 16 is able to
regulate the application of resistance to flywheel 12 by
manipulating resistance control 13 at any time.
[0016] Flywheel 12 is a perimeter weighted flywheel fixed to rotate
with front roller 3, the flywheel 12 having a radius of 7 to 10
inches and a mass of 40 to 60 pounds; in this case, it has a radius
of 8inches and a mass of 55 pounds.
[0017] For a flat disc of any thickness and even weight
distribution, there is a constant relationship between the
peripheral weight and the total weight. In Table 1, the
relationship is laid out:
[0018] Table 1--percent of weight in the periphery of a disc
flywheel of evenly distributed weight, measured at various
distances from the center, where r is the radius:
[0019] Outside 0.6r: 64%
[0020] Outside 0.7r: 51%
[0021] Outside 0.8r: 36%
[0022] Outside 0.9r: 19%
[0023] These percentages are true for a flywheel having evenly
distributed weight of any radius, but my invention calls for a
radius of 7 to 10 inches. This means, for example, that a plain,
evenly distributed mass flywheel of my minimum radius 7 will have
51% of its weight in the area outside 4.9 inches radius (0.7r). At
my maximum radius of 10 inches (as with a 7 inch disc), all of the
above percentages apply. My criteria also call for a mass of 40 to
60 pounds for the flywheel as a whole. Thus a 55 pound, 8 inch
flywheel will have 0.36.times.55, or 19.8, pounds in the area
defined by the outside (near the edge) 1.6 inches of radius; of
course it will satisfy all the other percentages of Table 1 also. A
flywheel of less than 7 inches radius will not have any mass at all
that far from its rotation center.
[0024] Persons skilled in the art will recognize that flywheels
need not be plain, evenly distributed discs. For example, they may
be hollowed out in the center or thin in various patterns, or may
be completely open in certain areas to define spokes or spoke-like
members. Such types of construction which may tend to reduce the
amount of weight near the center of the flywheel relative to that
near the perimeter are useful in my invention, so long as the total
weight and radius criteria are met. The flywheel should not be of a
shape or construction which distributes weight with an uneven bias
toward the center of the flywheel; it must be at least evenly
distributed or perimeter weighted. By "perimeter weighted" is meant
that the average of the centers of gravity for all radii is located
farther toward the perimeter than 0.5r, where r is the radius--that
is, the flywheel may have an uneven bias of weight toward the
periphery.
[0025] Persons skilled in the art will also recognize that the
rollers or spindles on which the belt turns also have a modest
flywheel effect. As discussed above, flywheel 12 is attached or
fixed directly onto front roller 3 so they turn together. Although
the roller 3 has a modest flywheel effect, my criteria for the
flywheel do not consider it, nor do they consider that the center
of the flywheel may be open--that is, completely absent--so the end
of front roller 3 can be inserted into it as shown. Thus, a
flywheel meeting my criteria of 40 to 60 pounds and having a radius
of 7 to 10 inches will include such a flywheel.
[0026] The flywheel 12 may be in the form and placement illustrated
or may be split into two perimeter weighted flywheel parts, one on
each end of front roller 3, each having a radius of 7 to 10 inches
and each having half of a total of 40 to 60 pounds. I consider this
arrangement a single flywheel. In either case--whether the flywheel
12 is on one end of the roller or two, as shown or split, with one
part on each end of front roller 3, its large diameter is
accommodated by the overall inclination of the treadmill. As
indicated by the difference in length between front legs 18 and
rear legs 19, frame 5 and treadmill surface 2 are maintained at an
angle from 9 to 20 degrees. In the case of FIG. 1, the angle is 12
degrees, as an angle of 11 to 13 degrees is preferred. Side rails
20 are an optional safety feature.
[0027] In FIG. 2, unlike the stance of the user in FIG. 1, the
exerciser assumes a more upright position but grasps handles 21 of
attachment 22 which has been inserted into support socket 6,
secured by pins 10. Resistance control 13 of FIG. 1 has been
replaced by knob 30 for varying resistance on flywheel 12, as will
be further explained with reference to
[0028] FIG. 5. Otherwise the treadmill is identical to the one
depicted in FIG. 1, comprising frame 5, treadmill belt 1, and
flywheel 12. Front legs 18 and rear legs 19 are of different
lengths in order to provide a slope of 11 degrees for the treadmill
surface 2.
[0029] In FIG. 3, the basic treadmill is also similar to that of
FIGS. 1 and 2, comprising frame 5, treadmill belt 1, and flywheel
12. In this case, however, front legs 18 and rear legs 19 are of
different lengths in order to provide a slope of 13 degrees for the
treadmill surface 2. But also, attachment support 25 holds a
crosspiece 26 to which are attached two reinforced pads 27 adapted
for contact with the user's shoulders. Handles 28 in this case
extend downwardly and outwardly so the user can exert part of his
strength on them if desired. Insert 29 snugly receives attachment
support 25 at its upper end. Handles 28 are welded or otherwise
firmly attached to insert 29, which fits into attachment socket 6
in a manner similar to the way stem 7 fits into attachment socket 6
in FIG. 1. With an appropriate resistance adjustment applied
through brake bracket 13, the resultant "uphill" exertion simulates
a football exercise device. It should be noted that, since the
treadmill does not require electricity, it may be placed on an
athletic field or anywhere remote from an electrical outlet.
[0030] The user in FIG. 4 has chosen to employ insert 29 and its
handles 28 without using attachment support 25 or the reinforced
pads 27 of FIG. 3. She assumes a more forward leaning posture than
the user in FIG. 3, pushing only on the handles 28, and is able to
take longer strides than the user in FIG. 3, who has chosen to
exert the most force on reinforced pads 27. The treadmill of FIG. 4
is otherwise similar to the treadmills of FIGS. 1, 2, and 3,
comprising treadmill belt 1, frame 5, and flywheel 12. The fixed
inclination of the treadmill in FIG. 4 is 12 degrees.
[0031] Since it is an object of the invention to eliminate the
expense of a motor, it is important to understand the effect of the
fixed, rather steep, inclination of the treadmill. Not having a
motor, there is no way to change the inclination of the treadmill
using external power. Of course, one can simply prop up the front
of the treadmill by placing a temporary platform under front legs
18 if additional slope is desired. The invention does not require a
variable slope, but if for some reason one would want to
incorporate a motor to vary the slope, it could be accommodated
without changing the basic relationship between the size of the
flywheel and the slope of the treadmill.
[0032] As indicated elsewhere herein, the flywheel should have an
outside diameter of 14 to 20 inches, and therefore the front of the
treadmill must be high enough for it to turn freely. As also
indicated elsewhere, its mass should be within a range of 40 to 60
pounds. Some of the effects of the heavy large-diameter, perimeter
weighted, flywheel are shown in the graphs in FIGS. 6 and 7. They
are based on an arbitrarily selected value of 24.5 kg (54.2 pounds)
for the flywheel assumed to be concentrated entirely in the form of
a torus. Where the radius of the torus from its center to the
middle of the ring on the other side is 0.2285 meter (9 inches) and
the radius within the torus body, or tube, is assumed to be zero,
applying the formula I=1/2mr.sup.2 where r is the radius of the
torus (taken from its center to the center of the cross section of
the torus tube, which is assumed to have a radius of zero), and m
is the mass of the torus, yields a mass moment of inertia I=0.64.
This number is used to develop the information in the following
paragraphs.
[0033] The exponential effect of the deliberately chosen long
radius of the flywheel results in an aggressive inertia. The
inertia created by the large perimeter weighted flywheel allows the
tread belt to move smoothly under heavy resistance by the braking
system. If such inertia is not created then the user would
experience a stop and start action of the tread belt while under
resistance by the braking system.
[0034] In a sense, all treadmills have fly wheels, motorized and
non motorized. Even where there is no device called a flywheel, the
rollers or spindles on which the belt turns store a certain amount
of energy as they are turned. It is a natural function of moving
the tread belt. But the previous designs of the flywheels have been
much smaller and weights are typically in the range of 10 to 18
pounds in wheels of smaller dimensions. My design is much
different. The size and weight differs but the function is the key.
My flywheel is designed to distribute a significant weight at
longer distances from the center and generally more than half way
to the edge, a technique which may be called "perimeter weighting."
The perimeter weighting, size of the OD (outside diameter) and
heavy weight all contribute to the principle of aggressive inertia
which I employ. The aggressive inertia drives the tread belt in a
way similar to a motorized driven unit. No other treadmill employs
my principle of aggressive inertia and perimeter weighting.
[0035] In FIG. 5, the mechanism of the brake is shown. Brake base
40 is mounted on pivot 41 and is integral to plate 42 through which
an elongate screw 43 passes. Brake pad 44 lines the concave surface
of brake base 40. Brake base 40 and brake pad 44 are positioned in
relation to pivot 41 and plate 42 so that the end of brake pad 44
nearest pivot 41 touches or almost touches the perimeter surface of
flywheel 12. The shaft 45 of elongate screw 43 passes through
bracket 13 and terminates in knob 30 when the brake is not
actuated. Bracket 13 and pivot 41 are fastened securely to frame 5
(not shown) in any suitable manner. Flywheel 12 is fixed to front
roller 3 as indicted in FIG. 1. To apply resistance to the flywheel
12, the user turns knob 30 clockwise to elevate plate 42, which
causes brake base 40 to urge brake pad 44 into increasing contact
with flywheel 12. Elongate screw 43 is made so that ten complete
clockwise rotations of knob 30 will fully apply brake pad 44 to
flywheel 12. The amount of resistance generated is generally
directly related to the turns of the knob 30. Resistance is reduced
by turning the knob 30 counterclockwise. Brake pad 44 may be made
of any suitable material offering some resilience and able to
tolerate the friction generated.
[0036] The effect of the aggressive inertia is graphically
illustrated in FIG. 6. FIG. 6 shows the percentage of speed change
for a single stride at two different speeds (a typical walking
speed and a typical running speed), over a wide range of slope. One
important thing to note here is what happens when the deck is
inclined at a slope steeper than 8.5 degrees, as in the present
invention. Basically, gravity is now assisting the user to the
point where the flywheel urges the belt to speed up. However, the
calculations of the graph are based only on the flywheel and a
hypothetical user. There is also present an inherent "drag" from
the contact of the belt on the rollers, the contact of the user's
feet on the belt (and the support surface under it), and the belt
tension both with and without the effect of the user's weight. The
user can easily achieve an equilibrium between the motion of the
belt and the force of his or her own stride, which can still vary
over a wide range of speed with or without application of the
brake. The user can, of course, hold onto the handles 17, 28 or
others, and/or can grasp side rails 20, while modifying his or her
stride if desired or deemed necessary; the user may also simply
step on the stationary sides of frame 5 next to the belt at any
time.
[0037] The data for FIG. 6 were calculated using an average body
weight of 175 pounds and speeds of 3 miles per hour walking and 8
miles per hour running. Note that the inclination angle affects the
percent change of speed more dramatically at a walking speed than
it does at a running speed. This may seem counterintuitive, but the
running speed value is higher to begin with. The user will find
that, with or without the appropriate application of the braking
mechanism, the belt motion will nevertheless be both challenging
and smooth. At a fixed slope of 12 degrees, for example, the
flywheel and braking mechanism are designed to provide a full range
of resistance and speeds.
[0038] FIG. 7 shows graphically the additional force required to
maintain a constant speed over the course of one stride, once the
treadmill has achieved the desired speed. Positive values indicate
additional force needed from the user; negative values indicate
that additional belt resistance is needed, Note that deck angles
higher than 8.5 degrees again show the need for additional
resistance. Steady resistance is easily provided by the brake
system. Again, the calculations do not include factors of friction
from the belt or other sources.
[0039] The versatility of the invention is illustrated in FIGS. 8a
to 8f. The basic treadmill comprising frame 5, treadmill belt 1,
and flywheel 12 is seen without attachments in FIG. 8a. Attachment
socket 6 is empty, ready for one of the attachments, but it is not
necessary for a user to install one. Lift handles 50 and rollers 51
are provided so the treadmill can readily be moved. FIG. 8a shows
knob 30 for controlling resistance by means of elongated screw 43
as shown in FIG. 5, but it may be replaced by levered resistance
control 13 (FIG. 8b) as shown in FIG. 1. Each of the attachments
shown in FIGS. 8c, 8d, and 8e has a stem 7 sized for secure
insertion into attachment socket 6 and adjustable for height using
pins 10. FIG. 8d shows a sled pad attachment. FIG. 8e is a forearm
attachment having an arm rest portion 15. The shoulder harness
attachment of FIG. 8c in this case has an intermediate collar 60
for handles 28. The steer's horn attachment of FIG. 8f has an
elongated socket 61 able to receive and fasten onto a shaft (not
shown) extending from attachment socket 6. Other types of
attachments may be designed and easily attached to the
treadmill.
[0040] This unit is eco-friendly, requires no external power and is
made of recycled steel. The incline is fixed at an optimal position
for cardio and muscle development. It has a wide range of
resistance, features a raised textured belt surface, and includes
various front hand stations (attachments) that are adjustable to
suit the user, particularly as to height.
[0041] Thus it is seen that my invention includes a motorless
treadmill comprising (a) a frame, (b) a high front roller and a low
rear roller held by the frame, (c) a continuous treadmill belt in
contact with the front and rear rollers, the treadmill belt having
an outer surface and an inner surface, the inner surface in contact
with the rollers, the rollers and the treadmill belt defining an
exercise surface inclined at a fixed angle of 9 to 20 degrees from
the low rear roller to the high front roller, (d) a flywheel fixed
to the front roller, the flywheel having a radius of 7 to 10 inches
and a perimeter weighted mass of 40 to 60 pounds.
[0042] My invention also includes a motorless treadmill comprising
(a) a treadmill frame including a front end and a rear end, the
frame including a treadmill belt, a front roller on the front end,
and a rear roller on the rear end, the front and rear rollers for
enabling the treadmill belt to turn, the treadmill frame including
at least one front support member fixedly elevating the front
roller at an angle of 9 to 20 degrees from the rear roller, (b) an
elongate socket fixed to the front end of the frame, the socket
being adapted to receive and fix a shaft of one or more
interchangeable handles for grasping by a user to assume a variety
of positions and apply a variety of muscles by a user, and (c) a
perimeter weighted flywheel fixed to the front roller, the
perimeter weighted flywheel having a mass of 40 to 60 pounds.
[0043] And, in another aspect, my invention includes a motorless
treadmill having a fixed inclination of 9 to 20 degrees comprising
(a) a frame including a socket for receiving an accessory shaft,
and (b) a plurality of accessory shafts adapted to fit securely in
said socket and having handles deployed in various
orientations.
* * * * *