Roto stepper exercise machine

An exercise machine designed to condition the lower body comprising a pair of foot receiving platforms which may be established to travel along circular paths following coordinates in all three spacial dimensions--longitudinal, lateral, and vertical. The circular paths which the foot platforms travel along may also be established to be coplanar, inclined, counter rotating, and overlapping; while constraining the foot platforms which cyclically travel along the path to remain mutually parallel and at constant lateral separation. A flywheel and/or frictional resisting means may be incorporated as desired.

BACKGROUND 
1. Field of Invention 
This invention pertains to an exercise machine, of a type designed to 
exercise lower body muscles. The resisting motion to which the lower body 
is subjected to when using this machine is unique, and may perhaps be best 
characterized as a combination of the resisting motions that would be 
experienced during the use of a bicycle, a stair stepper, and a skiing 
machine. 
2. Description of Prior Art 
The market is replete with exercise machines designed to exercise various 
muscle groups in the human body. Three popular categories of exercise 
machines designed to exercise the lower body are bicycle machines, stair 
steppers, and skiing machines. These machines have been successful because 
they offer an effective form of an aerobic, low impact exercise. 
Bicycle machines provide resistance to leg motion by causing two foot 
petals, which receive the feet of the user, to each resistively travel 
along a circular path, mutually in the same direction, about a coaxial, 
horizontal axis of rotation, while maintaining the pedals diametrically 
opposite and with constant lateral distance between them. 
Stair steppers provide resistance to leg motion such that work is performed 
during the unbending (or straightening) of each leg as two pedals or foot 
platforms are continuously and alternatively stepped upon and released. 
Skiing machines offer resistance to leg motion by allowing two foot 
platforms to alternately travel rearward with resistance and forward with 
minimal resistance in a linear side by side manner. During use, dependent 
upon the specific machine design, the two foot platforms may have to be 
continuously coordinated and synchronized by the user to be out of phase 
with each other by half of a cycle. 
OBJECTS AND ADVANTAGES OF THE PRESENT INVENTION 
This invention resistively subjects the lower body to a unique motion of 
greater complexity than any of the three categories of exercise machines 
described above. In terms of spatial geometry, each of the three 
categories of prior art machines described above may be referred to as two 
dimensional exercise machines; the bicycle machine with the pedals that 
rotate about a singular axis thereby causing the operators feet to move 
forward and back (longitudinal) for the first dimension, and up and down 
(vertical) for the second dimension; the stair stepper with the foot 
platforms which generally travel along an arcuate path about a singular, 
horizontal axis of pivotation, which causes the operators feet to move 
forward and back (longitudinal) to a minimal degree for the first 
dimension, and up and down (vertical) to a major degree for the second 
dimension; and the skiing machine with its linear, reciprocating foot 
platform motion that causes the feet to move forward and back 
(longitudinal) for the first and only direction. Thus, each of those 
machines only cause the foot platforms to move, at most, in two 
dimensions. The present invention uniquely operates the foot platforms in 
all three dimensions of spatial geometry, longitudinal, vertical, and 
transverse, thus enabling the user to exercise additional body muscles to 
achieve better results. The inventor, being a picture of fitness, 
recommends the use of this device as a challenging form of exercise. 
SUMMARY OF THE INVENTION 
In accordance with the preferred embodiment of this invention, two foot 
platform support members, each with their own distinct axis of rotation, 
has a foot platform rotatably installed at an outer end. The centerline 
distance between the axes of rotation of each of these foot platform 
support members, in conjunction with the magnitude of eccentricity of the 
foot platform support member outer ends, may be established to effect 
ideal operational characteristics. In the embodiments to be shown, the 
circular paths that the foot platforms are forced to travel along has been 
established to be overlapping, with minimal lateral separation, and with 
what the inventor considers to be the optimum diameter and inclination 
angle; but as the reader may surmise, these and other variables may be 
juggled to arrive at distinct operational characteristics. Additionally, a 
mechanical component may be incorporated upon this machine such that the 
two foot platforms are forced to remain parallel with respect to each 
other at all times. 
The overlapping circular paths that the foot platforms are forced to travel 
along are preferably inclined in order to establish the three dimensional 
operational characteristics. The platform support members, as in the case 
with the embodiments to be illustrated, may consist of tubular members 
bent at inner and outer distal ends to approximately thirty degrees. 
Support bearings are installed at the inner ends of these tubular members 
to provide means for the tubes to rotate. During use, the two platform 
support members are preferably synchronized by connected mechanical 
components such that they are maintained out of phase with each other by 
one half of a cycle or 180 degrees in counter rotational directions. The 
simplest and least expensive means to ensure synchronization is to install 
a pair of intermeshing gears or toothed wheels onto the two platform 
support tubes, in proximity to the support bearings. If parallelism 
constancy between the two platform is desired, an optional foot platform 
orientation member, contained within each platform support tube, may be 
connected nonrotatably relative to the machine frame at an inner distal 
end, and nonrotatably at an outer distal end to each respective rotatably 
mounted foot platform. The method chosen to prevent the orientation member 
from rotating about its longitudinal axis must however allow pivotation or 
longitudinal angular misalignment at the distal end connections. The 
nonrotating foot platform orientation members employed within the platform 
support tube may for example consist of shafting with U-joints, flexible 
drive cable, flexible couplings, bevel or hinged gears, or a slotted or 
solid rigid bar with torque receiving members at each distal end. In order 
to provide inertial characteristics during operation, a mechanical 
flywheel, with its respective driven pulley, may be optionally installed 
remote from the platform support members, and belt or chain driven by a 
drive pulley secured at an inner end to one of the rotatable platform 
support members. If frictional resistance is desired, a fan may be used in 
place of the flywheel; or an adjustable friction brake may be installed to 
actuate upon the flywheel, the gears, or even directly upon the foot 
platform support tube. Additionally, if a mechanical flywheel is 
installed, an overrunning clutch may, for example, be located between a 
driven platform support member and the flywheel drive pulley so as to 
allow the operator to cease motion of the foot platforms without the 
consequence of having to exert force to stop the flywheel. It should be 
noted that by providing a bidirectional, mode convertible one way clutch 
to the flywheel, the user would be able to operate the foot platforms in 
either counter rotating direction. Of course, an artificial flywheel, such 
as electronic, would in many respects simplify the mechanism. 
In describing the three spatial dimensions (or albeit somewhat 
inaccurately: degrees of freedom) that the operator will experience, the 
first spatial dimension corresponds to the forward and back (longitudinal) 
motion as the foot pedals travel along their inclined circular paths. The 
magnitude of this first dimension is inversely proportional to the angle 
to which the plane defining the circular path has been inclined rearwardly 
from horizontal. The second spatial dimension corresponds to up and down 
(vertical) motion as the foot platforms travel along their inclined 
circular paths. The magnitude of this second dimension is directly 
proportional to the rearward inclination angle of the circular path plane, 
and as follows, would be zero if the path is level. The third and final 
spacial dimension corresponds to side to side (transverse) motion as the 
foot platforms travel along their circular path, and, because the path 
plane has not been inclined transversely, the magnitude of this third 
dimension is not a function of the degree to which the path angle has been 
rearwardly inclined. 
In describing how one would exercise with this machine, note that, unique 
to this machine, it is preferable from a balance and coordination aspect 
to have the foot platforms rotate at the same angular velocity, with 
respect to each other, in a counter rotating manner; although it would be 
possible to operate this machine if they rotate in the same direction. 
Within the counter rotating mode, two separate directional distinctions 
are possible; that which causes the foot platforms to pass down between 
the tubular axes of rotation, at the transverse center of the machine, or 
that which causes each of the foot platforms to pass down at their 
respective outer transverse side of the machine. Counter rotating the foot 
platforms such that they pass down at the transverse central region of the 
machine will ensure that the operator's feet will effortlessly remain 
situated on the foot platforms, without the necessity of foot straps and 
the like. Counter rotating the foot platforms such that they pass down at 
their respective outer transverse side of the machine may be desirable to 
work different muscles, and result in a more demanding exercise. It may 
also be noted that although this machine is illustrated with the intent 
that the operator face forward, a beneficial effect would also be derived 
if the foot platforms are alternatively designed to accommodate the user 
to stand facing rearward as well. Such a design modification may for 
example entail centralizing the optional foot straps, or providing means 
for the foot platforms to be longitudinally reversed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the figures, I have illustrated in FIG. 1 a front 
perspective view of the assembled machine, where foot platform 20, with 
heel stop 24, is shown to present a level platform upon which the 
operator's right foot is to be placed. The circular path 26, about which 
the right foot platform 20 will travel during operation, is inclined 
rearward sixty degrees from horizontal, and is represented with a dashed 
line. The right foot platform 20 is illustrated at its uppermost position 
along this travel path. The left foot platform 21 is illustrated at the 
lowermost position along its travel path. The tubular members supporting 
the foot platforms each consist of three portions; an outer thirty degree 
tubular elbow 30, an intermediate tube 40, and inner thirty degree tubular 
elbow 50. Housing side 14, housing shroud 12, and handle bar 10 encloses 
most of the mechanism, and enable the operator to safely operate the 
machine. It may be noted that the stationary handle bar may be replaced 
with handles which move under resistance, if an upper body workout is also 
desired. Such handles may for example pivot about an axis perpendicular to 
the side of the machine, and be bent such that the hand grips are located 
at a comfortable position to operate. Because various designs of upper 
body workout handles, poles, or cranks or levers are incorporated upon 
many different categories of exercise machines, the potential for 
including any one of them upon this machine is considered obvious. 
Referring now to FIG. 2, a frontal perspective view is illustrated of most 
of the portions of the mechanism that would be visible, if the housing of 
the machine was to be removed. Right foot platform 20 and left foot 
platform 21 are each shown oriented at the three o'clock position. Because 
each of the rotating platform support members rotates about their 
respective tube support bearings 60, and because the counter rotating 
gears 70 are in mesh with one another, as right foot platform 20 moves 
upward, left foot platform 21 will simultaneously move downward. Gear hub 
75 secures gear 70 in a fixedly manner to inner tubular elbow 50. It may 
be noted that, if gears or toothed wheels are employed to provide the 
means to cause the platform support members to synchronously counter 
rotate, they may be constructed of plastic due to low torque requirements. 
Furthermore, although a pair of gears are illustrated, it would be obvious 
to the reader that any number of gear pairs would establish the same 
counter rotational action. Continuing now, flywheel drive pulley 80 is 
fixedly secured to inner tubular elbow 50, and drives flywheel driven 
pulley 85. Flywheel 90 is rotationally secured by flywheel shaft 92, said 
shaft being rotatably secured at one end by flywheel bearing 94. Flywheel 
drive member 82 may an endless `V` belt, a timing belt, or a roller chain. 
Flywheel drive pulley 80 may therefore alternatively be of a sprocket 
design. As indicated earlier, the installation of a flywheel may be 
considered optional. 
Continuing with FIG. 2, a hidden set of tube support bearings are installed 
away from the viewer, on the opposite side of the counter rotating gears 
70. Also, any optional mechanisms contained within the tubular support, or 
protruding out of and/or attached to each distal end of the tubular 
supports are not illustrated. 
Directing the reader's attention to FIG. 3, a side plan view is shown of 
the assembled machine. Handle bar 10 is secured to housing side 14 to 
provide a hand grip surface for safety purposes. Right foot platform 20 is 
shown as it would appear in this view if it was oriented at the twelve 
o'clock position, while left foot platform 21 is oriented at the six 
o'clock position. Both foot platforms are of a design which locates the 
platform rotational axis above the foot contact area with respect to 
gravity. This allows the foot platforms to hang in a downward position if 
platform orientation members are not provided. Intermediate tube 40 is 
threaded into outer tubular elbow 30 and also into inner tubular elbow 50. 
Referring now to FIG. 4, a side view is again shown, but in this view the 
right foot platform 18, as well as the left foot platform, are orientated 
at the three o'clock position. The left foot platform is therefore hidden 
from this view. Connected to right foot platform 18, and protruding out of 
outer thirty degree elbow 30 is outer synchronous shaft 25. Outer 
synchronous shaft 25 is maintained nonrotatable relative to the machine 
frame, and also nonrotatably relative to foot platform 18, and therefore 
maintains constant orientation of its respective foot platform as the foot 
platform travels along its circular path. It may be noted that if it is 
desired to make the inclination angle of the paths of the foot platforms 
adjustable, the function of the orientation members is unchanged. A foot 
platform orientation member is required with the design of the foot 
platform illustrated in this figure because the design of the foot 
platform illustrated in this figure is such that the foot platform 18 
rotational axis is positioned below the foot platform foot contact area 
with respect to gravity. Foot platform orientation members are not 
required if the platform rotational axis is positioned above the foot 
platform foot contact area. Intermediate tube 40, outer tubular elbow 30, 
and inner tubular elbow 50 assemble to form the platform support member. 
Section line 6--6, taken at a central plane of the tubular platform 
support members will reveal additional detail in FIG. 6. 
Referring now to FIG. 5A through FIG. 5H, front perspective views are shown 
of the machine as the right foot platform and left foot platform 20 and 21 
respectively, are moved along their counter rotational circular travel 
paths in increments of forty-five degrees. Starting with FIG. 5A, both 
foot platforms are oriented at the three o'clock position. FIG. 5B shows 
the right foot platform at the one thirty o'clock position, while the left 
foot platform is shown at the four thirty o'clock position. FIG. 5C 
illustrates the right foot platform at the twelve o'clock position or at 
zero degrees, while the left foot platform has moved 180 degrees to the 
six o'clock position. Referring now to FIG. 5D, the right foot platform 
has moved to the ten thirty o'clock position, and the left foot platform 
has moved to the seven thirty o'clock position. Continuing now with FIG. 
5E, both foot platforms are oriented at the nine o'clock position or at 
270 degrees. Directing attention now to FIG. 5F, and counter rotating the 
foot platforms along their respective circular paths an additional 
forty-five degrees, we have the right foot platform shown at the seven 
thirty o'clock position, while the left foot platform is shown at the ten 
thirty o'clock position. Referring now to FIG. 5G, the right foot platform 
has moved to the six o'clock position, while the left foot platform has 
moved to the twelve o'clock position, and concluding at FIG. 5H where the 
right foot platform is positioned at the four thirty-o'clock position, and 
the left foot platform has moved to the one thirty o'clock position, at 
which point the cycle is about to repeat. It is significant to note, from 
a desirable operational characteristic, that at all times throughout this 
cycle, the traverse distance between the foot platforms remains constant. 
Directing attention now to FIG. 6, a cross sectional view is shown taken 
along section line 6--6 in FIG. 4. Right and left foot platforms 17 and 18 
respectively are threaded at foot platform threads 26 to receive foot 
platform shaft 25. Foot platform shaft 25, although allowed to travel 
along the circular path of the foot platforms, does not rotate about its 
own longitudinal axis with respect to the stationary machine frame, and 
thus always maintains constant rotational orientation relative to the 
frame or housing of the machine. The outer distal end of outer tubular 
elbow 30 has a combination roller and thrust bearing 28 pressed thereupon. 
Shaft collar 27 locks the inner race of thrust bearing 28 to foot platform 
shaft 25. Fixed to foot platform shaft 25 by foot platform shaft pin 32 is 
outer synchro shaft 34. Foot platform shaft needle bearing 33 provides 
additional radial support during the cantilevered load applied to the foot 
platforms during machine operation. Outer U-joint 36 is pinned to outer 
synchro shaft 34, and is also pinned to intermediate synchro shaft 42. 
Intermediate tube 40 is threaded to outer tubular elbow 30 at outer end 
thread interface 38, and is also threaded to inner tubular elbow 50 at 
inner end thread interface 39. Intermediate synchro shaft 42 is connected 
to inner synchro shaft 52 at inner U-joint 56. Typically, a standard 
u-joint is suitable for an angular misalignment of thirty degrees, but if 
more severe misalignment is desired, double u-joints may be advisable. 
Also note that this figure depicts the correct installation orientation of 
u-joints when utilized for this type of application in that the connecting 
shafts are in the same plane and the joints are arranged to operate at 
equal angles with the bearing pins of the yokes on the intermediate shaft 
42 in line with each other. 
Continuing with FIG. 6, frame structural member 16 secures tube support 
bearings 60 at each proximate side of the pair of counter rotating gears 
70. Inner synchro shafts 52 are fixed to stationary bar 86 by bar pins 85. 
Sleeve hub 54 is pressed into inner distal end of right inner tubular 
elbow 50 to support a one way overrunning clutch 82 of flywheel drive 
pulley 80. Inner synchro shafts 52 are guided out of inner tubular elbows 
50 on the right at inner synchro needle bearing 84, and on the left at 
inner synchro ball roller bearing 68. 
Referring now to FIG. 7, a cross sectional view of a tubular support member 
is shown which utilizes flexible cable as the foot platform orienting 
member. Right and left foot platforms 20 and 21 respectively are of the 
design illustrated in figure one. Foot platform tubular support members 
110 each have two sweeping bends which result in the inner and outer 
distal ends of each of the tubular support members to become offset and 
parallel. Flexible cable 102 is secured to foot platform shaft 22 at 
sleeve 118. Sleeve needle bearing 115 provides additional support for foot 
platform shaft 22. Frame 16 houses tubular support bearings 60, and the 
overrunning clutch bearing 82 allows the flywheel drive pulley 80 to free 
wheel in one direction thus permitting the operator to cease motion while 
the optional flywheel coasts to a gradual stop. Counter rotating gears 70 
are secured to tubular support member 110 by a press fit, or by the 
utilization of set screws, eccentric collars, and the like. In order to 
provide for the smoothest operation, cable coating 103 may be provided 
wherever the cable is in contact with the interior surface of rotating 
tubular support member 110. The selection of the foot platforms 20 and 21, 
which have rotational axes above the foot contact area with respect to 
gravity, minimize operation difficulties which may be experienced due to 
windup of the cable as caused by torsion. 
Directing attention now to FIG. 8, a platform support member with an 
accompanying foot platform is shown in a perspective view. Tubular member 
120 has a pair of needle bearings 125 at each distal end, and are housed 
at the inner distal end within a machine frame structural member, and at 
the outer distal end within foot platform 130 inner shroud 131. Foot 
platform 130 also has incorporated upon it a top foot loop 132 to assist 
in maintaining foot placement onto the foot platform. 
Referring now to FIG. 9, a cross section of the assembly shown in FIG. 8 is 
illustrated. Tubular member 120 is rotatably supported at its inner end 
with needle bearings 125, and rotatably supports the foot platform 130 at 
inner shroud 131. Rocker joint 140 is a unique design which will receive 
and allow angular misalignment of a square profiled foot platform 
orientation shaft 135 in order to maintain constant orientation of the 
foot platform 130. The rocker joint 140 in proximity to the inner end of 
tubular member 120 is nonrotatably attached to a machine stationary 
structural member or the machine frame, and the rocker joint in proximity 
to the outer end of tubular member 120 is nonrotatably attached to the 
foot platform 130, thus the foot platform will maintain constant 
rotational orientation with respect to the machine frame as the foot 
platform rotates and travels along its circular path. 
Continuing, and directing attention now to FIG. 10, the square profiled 
foot platform orientation shaft 135 is shown engaged with rocker joints 
140 at each distal end, and is shown passing through each of the rocker 
joints during the design angular misalignment of thirty degrees. The 
incorporation of a polygonal cross sectioned orientation shaft enables the 
rocker joints to be of a compact design; however, due to the use of a 
rigid bar as the orientation shaft, the internal diameter of the platform 
support member is dictated by geometrical considerations as the shaft 
pivots about its inner end within the platform support member's tubular 
bends. By so enlarging the internal diameter of these foot platform 
support members, manufacturing costs can be reduced because each support 
member need not be a threaded assembly. 
Referring now to the rocker joint 140 illustrated in FIG. 11, the tapered 
surface 142 is oriented at an angle of thirty degrees with respect to the 
longitudinal axis of the joint. This will allow thirty degrees of angular 
misalignment with the square profiled orientation shaft. Arcuate edge 143 
is circular in definition as viewed in the direction of the longitudinal 
axis of the joint. 
Continuing now with FIG. 12, an alternative design of the torque 
transmitting elements at one distal end of the orientation member is 
illustrated in an enlarged perspective view. This design is similar to 
constant velocity (CV) joints used in the automotive industry and may be 
one of the preferred versions due to low manufacturing expense. Foot 
platform orientation shaft 144 transmits torque to the foot platform at 
the shaft distal end at cross piece 145. Cross piece 145, arbitrarily 
shown configured as a `T`, as opposed to a triadic or quadripartite 
arrangement, is nonrotatably connected to foot platform orientation shaft 
144, and forcibly engages cup groove side 147 while performing its 
function of maintaining constant orientation of the foot platforms. Foot 
platform orientation shaft 144 does not rotate about its own longitudinal 
axis, although it is allowed of course to pivot in proximity to its inner 
distal end as the foot platform travels along its circular path. Cup 
groove bottom 146 may be allowed to make sliding contact with cross piece 
145. In order to nonrotatably secure the cup or torque receiving member to 
a foot platform, bolt holes 149 may be provided. 
It should be noted that alternative designs may be substituted for the 
designs illustrating the foot platform orientation members. One such 
design, which would accomplish the same result, would be to employ an oval 
or noncircular shaft member, which would be received by an oval or 
noncircular female joint suitably chamfered to allow the designed shaft 
angular misalignment. Another such design which may be favored due to low 
manufacturing cost would involve longitudinally slotting the shaft at a 
distal end, and loosely passing through it a torque pin secured rigidly to 
the interior walls of a collar or sleeve (or torque receiving member) into 
which the slotted shaft end is inserted. Because multiple designs of the 
foot platform orientation member are thereby possible, only four of such 
are illustrated. 
Directing attention now to FIG. 13, a perspective view is illustrated, 
operationally deployed, of a collapsible design of this invention. Base 
frame 154 is locked to housing 150 in the downward position, and handle 
bar 152 is locked in the upward position. Foot platforms 130 are oriented 
to the three o'clock position. If desired, frictional resisting means and 
a mechanical flywheel, or simply an electronic flywheel, may easily be 
incorporated within the physical constraints of housing 158. 
Referring to FIG. 14, a perspective view of the collapsible embodiment is 
shown collapsed for storage or portability. Prior to collapsing, the foot 
platforms 130 are oriented to the three o'clock position (or nine o'clock 
position), and then the handle bar 152 is folded down to a stop. The base 
frame 154 may in turn be pivoted up to its stop, and then all three 
components locked together to facilitate transport or storage. 
Directing attention now finally to FIG. 15, an embodiment is illustrated 
which shows some of the mechanics if sprockets (or toothed pulleys or 
toothed wheels) with an accompanying flexible, endless component such as a 
timing belt or roller chain is utilized. It may be noted that employing a 
belt as the counter rotational ensuring element readily enables the center 
line spacing of the sprockets to be adjusted, and thus by also providing 
adjustability of the length of the platform support members, the 
theoretical `three degrees of freedom` is more closely approximated. 
Continuing with FIG. 15, double sided timing belt 164 will engage around 
sprockets 160 such that counter rotation of the pulleys occurs. Idle 
pulley 162, illustrated with side flanges to prevent the belt from 
`walking off`, need not have teeth present; and establishes a 
noninterfering route of the timing belt to the flywheel/fan pulley 166. 
The combination flywheel/fan provides both the characteristic angular 
momentum of a flywheel due to the weighted circumference 168, and the 
movement of air during rotation at fan blades 170. It may be of interest 
that the inherent design of this machine uniquely lends itself for the 
installation of a fan which is directed toward the operator, a distinction 
from other categories of exercise machines which utilize a fan for the 
motion resisting component. If additional rotational resistance is 
desired, an adjustable band brake may be installed to tighten against the 
weighted circumference 168. As indicated earlier, a roller chain may be 
substituted for a timing belt, and routed about sprockets secured to each 
platform support member in much the same manner. Some other less well 
known analogous components involve gear drive chains, gear drive belts, 
cable chain, synchronous cable with synchronous cable pulleys, and 3-D 
belt with 3-D pulleys. 
Counter rotation of the platform support members could also be ensured by 
incorporating complicated epicyclic gearing (a gear system involving 
planetary and sun gears), or tapered gears in order to establish the path 
in which each of the foot platforms travel along to lie in separate, 
inclined planes with respect to each other. In the latter case, the 
rotational axes of the tubular support members would be nonparallel. Also, 
in discussing additional coupling means to ensure counter rotation of the 
two platform support members, a multiple link system, with its 
accompanying cranks and rocking arms, may be utilized which gould offer 
both durability and quiet operation. 
It should be reemphasized that mechanical synchronization of the platform 
support members, although highly desirable, is not absolutely mandatory, 
therefore enabling the employment of additional flexible, endless 
components such as toothless flat belts, V-belts, diamond cross sectioned 
profiled belts; or even round belts which in the latter case may be 
allowed to cross between pulleys. 
This concludes the description of the invention, and while the above 
description contains many specificities, these should not be construed as 
limitations on the scope of the invention, but rather as an 
exemplification of several of the preferred embodiments there of. 
Accordingly, the scope of the invention should not only be determined by 
the text discussion and the embodiments illustrated, but also by the 
appended claims and their legal equivalents.