U.S. patent application number 12/778030 was filed with the patent office on 2010-09-30 for self-propelled vehicle propelled by an elliptical drive train including foot retention.
This patent application is currently assigned to PT MOTION WORKS, INC.. Invention is credited to Bryan Pate, Brent Teal.
Application Number | 20100244399 12/778030 |
Document ID | / |
Family ID | 39416167 |
Filed Date | 2010-09-30 |
United States Patent
Application |
20100244399 |
Kind Code |
A1 |
Teal; Brent ; et
al. |
September 30, 2010 |
Self-Propelled Vehicle Propelled by an Elliptical Drive Train
Including Foot Retention
Abstract
An apparatus including a frame; a drive wheel coupled to the
frame; a first and second foot link operably coupled to drive wheel
to transfer power to said drive wheel so as to propel the
apparatus, each including a foot receiving portion for receiving an
operator's foot and a retention mechanism for retaining the
operator's foot on the foot receiving portion of the foot link.
Inventors: |
Teal; Brent; (Solana Beach,
CA) ; Pate; Bryan; (Atherton, CA) |
Correspondence
Address: |
PROCOPIO, CORY, HARGREAVES & SAVITCH LLP
525 B STREET, SUITE 2200
SAN DIEGO
CA
92101
US
|
Assignee: |
PT MOTION WORKS, INC.
Solana Beach
CA
|
Family ID: |
39416167 |
Appl. No.: |
12/778030 |
Filed: |
May 11, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11899100 |
Sep 4, 2007 |
7717446 |
|
|
12778030 |
|
|
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|
60860570 |
Nov 21, 2006 |
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Current U.S.
Class: |
280/221 |
Current CPC
Class: |
A63B 22/205 20130101;
B62M 1/26 20130101; B62K 3/002 20130101 |
Class at
Publication: |
280/221 |
International
Class: |
B62M 1/02 20060101
B62M001/02 |
Claims
1. An apparatus, comprising: a frame; a drive wheel coupled to the
frame; a first and second foot link operably coupled to drive wheel
to transfer power to said drive wheel so as to propel the
apparatus, each including a foot receiving portion for receiving an
operator's foot and a retention mechanism for retaining the
operator's foot on the foot receiving portion of the foot link.
2. The apparatus of claim 1, where the retention mechanism includes
a structure operable to engage a top surface of an operator's foot
situated on the foot receiving portion of the foot link.
3. The apparatus of claim 1, where the retention mechanism is fixed
in one location on the foot link.
4. The apparatus of claim 1, where the retention mechanism is
adjustable to allow for at least two repeatable positions of an
operator's foot on the foot receiving portion.
5. The apparatus of claim 1, where each foot link has a first and a
second end, and the foot receiving portion is located between the
first and second ends of its respective foot link.
6. An apparatus, comprising: a frame having a drive wheel rotatably
supported thereupon, and a first pivot axis defined thereupon; a
first and a second foot link, each having a first end, a second
end, a foot receiving portion defined thereupon, and a foot
retention mechanism operable to inhibit an operator's foot from
disengaging from the foot receiving portion of the foot link; a
coupler assembly which is in mechanical communication with said
pivot axis and with a first end of each of said first and second
foot links, said coupler assembly being operative to direct said
first ends of said foot links in an arcuate path of travel; a foot
link guide supported by said frame, said guide being operable to
engage a second end of each of said foot links, and to direct said
second ends along a reciprocating path of travel; a power transfer
linkage in mechanical communication with said coupler assembly and
with said drive wheel; whereby when the first end of one of said
foot links travels in said arcuate path and the second end of that
foot link travels in said reciprocal path, an operator's foot
supported thereupon travels in a generally elliptical path of
travel, and said power transfer linkage transfers power from said
coupler assembly to said drive wheel, so as to supply propulsive
power thereto.
7. The apparatus of claim 6, where the retention mechanism includes
a structure operable to engage a top surface of an operator's foot
situated on the foot receiving portion of the foot link.
8. The apparatus of claim 6, where the retention mechanism is fixed
in one location on the foot link.
9. The apparatus of claim 6, where the retention mechanism is
adjustable to allow for at least two repeatable positions of an
operator's foot on the foot receiving portion.
10. The apparatus of claim 6, where each foot receiving portion is
located between the first and second ends of its respective foot
link.
11. An apparatus, comprising: a frame having a drive wheel
rotatably supported thereupon, and a first pivot axis defined
thereupon; a first and a second foot link, each having a first end,
a second end, a foot receiving portion defined thereupon and a foot
retention mechanism operable to inhibit an operator's foot from
disengaging from the foot receiving portion of the foot link; a
coupler assembly which is in mechanical communication with said
pivot axis and with a first end of each of said first and second
foot links, said coupler assembly being operative to direct said
first ends of said foot links in an arcuate path of travel; a foot
link guide track supported by said frame, said foot link guide
track being operable to engage a second end of each of said foot
links, and to direct said second ends along a reciprocating path of
travel; a power transfer linkage in mechanical communication with
said coupler assembly and with said drive wheel; whereby when the
first end of one of said foot links travels in said arcuate path
and the second end of that foot link travels in said reciprocal
path, a user's foot supported thereupon travels in a generally
elliptical path of travel, and said power transfer linkage
transfers power from said coupler assembly to said drive wheel, so
as to supply propulsive power thereto.
12. The apparatus of claim 11, where the retention mechanism
includes a structure operable to engage a top surface of an
operator's foot situated on the foot receiving portion of the foot
link.
13. The apparatus of claim 11, where the retention mechanism is
fixed in one location on the foot link.
14. The apparatus of claim 11, where the retention mechanism is
adjustable to allow for at least two repeatable positions of an
operator's foot on the foot receiving portion.
15. The apparatus of claim 11, where each foot receiving portion is
located between the first and second ends of its respective foot
link.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No.
11/899,100 filed on Sep. 4, 2007 and claims priority to Provisional
Application Ser. No. 60/860,570, filed Nov. 21, 2006 under 35
U.S.C. 119(e). All of these applications are incorporated herein in
their entirety by this reference.
FIELD OF THE INVENTION
[0002] The present invention generally relates to bicycles. More
particularly, the invention concerns a bicycle having an elliptical
drive train.
BACKGROUND OF THE INVENTION
[0003] The most common human-powered vehicle is the bicycle. Use of
the bicycle for exercise, recreation, and transportation is
well-known. Operators of conventional bicycles are in a seated
position and pedal in an essentially circular motion to perform the
mechanical work necessary to propel the vehicle. During operation,
the operator's upper body is typically bent forward at the waist
and held in place by the muscles of the arms, shoulders, abdomen,
and lower back. This most common riding position is relatively
stressful. Bicycle riders often experience pain, discomfort, and/or
numbness in the pelvic region from sitting on the bicycle seat or
"saddle", and discomfort in the lower back, arms, and shoulders
from the bent-over riding position.
[0004] To alleviate the discomfort associated with prolonged use of
conventional bicycles, recumbent bicycles in which the operator
propels the bicycle from a reclined position are known. Although
recumbent bicycles alleviate much of the discomfort associated with
conventional bicycles, the reclined riding position makes these
vehicles less stable and more difficult to ride. The recumbent
bicycle is also limited as a commuter vehicle because the
low-to-the-ground configuration allows obstacles to easily obstruct
the operator's line of sight and makes him or her less visible to
other vehicles, cyclists, and pedestrians. In addition, because
operators of conventional and recumbent bicycles are seated, they
do not receive the musculoskeletal benefits of weight-bearing
exercise when operating these vehicles.
[0005] Therefore, there remains a need to overcome one or more of
the limitations in the above-described, existing art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 shows a perspective view of one embodiment of the
bicycle;
[0007] FIG. 2 shows a side elevation view of the bicycle of FIG. 1,
depicting schematically the elliptical pedaling profile;
[0008] FIG. 3 shows a side elevation view of the bicycle of FIG. 1,
depicting schematically an operator's zone;
[0009] FIG. 4 shows a perspective view of another embodiment of the
bicycle;
[0010] FIG. 5 shows a perspective view of yet another embodiment of
the bicycle;
[0011] FIG. 6 shows a perspective view of yet another embodiment of
the bicycle;
[0012] FIG. 7 shows a perspective view of yet another embodiment of
the bicycle that includes an adjustable guide track;
[0013] FIG. 8 shows a close-up perspective view of adjustable crank
arms that may be coupled to the bicycle;
[0014] FIG. 9A shows a perspective view of one embodiment of an
adjustable foot platform that may be coupled to the bicycle;
[0015] FIG. 9B shows a perspective view of another embodiment of an
adjustable foot platform that may be coupled to the bicycle;
[0016] FIGS. 10A-L show side elevation views of different
embodiments of load wheel retention devices that may be coupled to
the bicycle;
[0017] FIG. 11 shows a perspective view of one embodiment of an
adjustable steering tube that may be coupled to the bicycle;
[0018] FIG. 12 shows a perspective view of one embodiment of a
direct drive system that may be coupled to the bicycle;
[0019] FIG. 13A shows a perspective view of another embodiment of
the bicycle that includes a foldable frame;
[0020] FIG. 13B shows a perspective view of the bicycle depicted in
FIG. 13A after it has been folded; and
[0021] FIG. 14 shows a perspective view of yet another embodiment
of the bicycle.
[0022] It will be recognized that some or all of the Figures are
schematic representations for purposes of illustration and do not
necessarily depict the actual relative sizes or locations of the
elements shown. The Figures are provided for the purpose of
illustrating one or more embodiments of the bicycle with the
explicit understanding that they will not be used to limit the
scope or the meaning of the claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] In the following description, for the purposes of
explanation, numerous specific details are set forth in order to
provide a thorough understanding of the bicycle of the present
invention. It will be apparent, however, to one skilled in the art
that the bicycle may be practiced without some of these specific
details. For example, a variety of load wheel retention devices may
be employed. Throughout this description, the embodiments and
examples shown should be considered as exemplars, rather than as
limitations on the bicycle. That is, the following description
provides examples, and the accompanying drawings show various
examples for the purposes of illustration. However, these examples
should not be construed in a limiting sense as they are merely
intended to provide examples of the bicycle rather than to provide
an exhaustive list of all possible implementations of the
bicycle.
[0024] The present disclosure relates generally to human-powered
transportation, and more specifically to transport, exercise, and
recreational vehicles powered by an elliptical pedaling motion that
generally mimics the kinematics of walking or running. The
apparatus, of which one embodiment is a bicycle, described herein
provides an improved means of human-powered transportation that has
advantages over conventional bicycles, scooters, upright
step-cycles, and other human-powered vehicles.
[0025] As defined herein, a "bicycle" is every vehicle propelled,
at least in part, by human power in the form of feet, or hands,
acting upon pedals, having at least two wheels, except scooters and
similar devices (which are defined as vehicles operated by a foot
contacting the ground). The term "bicycle" also includes three and
four-wheeled human-powered vehicles.
[0026] More specifically, disclosed herein is a low cross-over
height bicycle powered by an elliptical pedaling motion that
generally mimics the kinematics of running or walking and provides
a means of human-powered transportation that has advantages over
conventional upright step-cycles, bicycles, and scooters. Also
disclosed herein are methods for enabling the operator to adjust
the pedaling profile of such a vehicle.
[0027] An upright step-cycle is known in the art, but has several
drawbacks. For example, the length of the wheelbase of several
upright step-cycles described limits the means by which they can be
transported in another vehicle, such as a passenger car, and
prevents them from being turned around on narrow bike paths or
streets without the operator dismounting the vehicles. Conventional
upright step-cycles also have sprockets and a chain positioned near
the operator. If contacted, these moving parts can damage the
operator's clothing and/or injure the operator. Furthermore,
conventional upright step-cycles have frames that position support
structures in the operator's zone, discussed in detail below. Frame
members located in the operator's zone are likely to injure the
operator if he or she contacts them while riding or during a fall.
Frame members located in the operator's zone also make mounting and
dismounting the vehicle more difficult.
[0028] In addition, conventional upright step-cycles lack several
features that could enable the operator to easily modify the
vehicle's pedaling profile and thereby allow a single vehicle to be
adjusted to accommodate a wide range of different sized riders. As
discussed above, the path of motion through which the operator's
foot travels while pedaling these vehicles is generally elliptical.
Some people prefer this generally elliptical motion to the
generally circular motion used to propel a conventional or
recumbent bicycle because the generally elliptical motion more
closely mimics walking, running, or climbing and has been shown to
be a more effective means for strengthening the leg muscles than
cycling while avoiding much of the stress and impact generated by
running. However, because the pedaling motion mimics human
movement, operators with different anatomical dimensions will
generally require different pedaling profiles. Specifically, a
taller operator would likely require a pedaling profile with a
longer stride length than a shorter operator would. In addition, a
more aggressive operator might prefer a steeper foot platform
take-off angle so that he or she could generate more low-end
torque, while a less aggressive rider might prefer a flatter
pedaling profile to reduce foot and knee flexion during the pedal
stroke.
[0029] As discussed below, the shape of the pedal stroke is
generally determined by the length of the crank arms, the length of
the foot links, the location of the foot platforms on the foot
links, and the angle of the foot link guide tracks. Conventional
upright step-cycles lack easy methods for adjusting the length of
the crank arms and the location of the foot platforms. Enabling
operators to easily optimize the pedaling profile by adjusting
these aspects of the propulsion system would enhance the
functionality of an upright step-cycle.
[0030] Another form of human-powered transportation is the scooter.
Conventional scooters are operated in a standing position. The
operator propels a scooter forward by pushing one leg against the
ground in a rearward direction. Scooters have the advantage of
being more comfortable to ride than conventional bicycles without
many of the drawbacks of recumbent bicycles. Because the operator
of a scooter rides in an upright position, he or she does not
experience the numbness and pain caused by sitting on a seat or
saddle. In addition, the operator is less susceptible to shoulder
and lower back pain because he or she is not hunched over the
handlebars. As compared to a recumbent bicycle, the operator's
standing position reduces the likelihood that his or her line of
sight will be obstructed and makes him or her more visible to other
vehicles and pedestrians. A scooter is also more stable and easier
to ride than a recumbent bicycle, thereby reducing the frequency of
falling for unskilled operators. Moreover, riding a scooter is a
weight-bearing exercise that provides the operator with a means of
strengthening the leg muscles and bones that is not available to
operators of conventional and recumbent bicycles.
[0031] However, the scooter does have disadvantages. Although an
operator can travel longer distances at higher speeds on a scooter
than he or she generally could by walking or running, a scooter's
propulsion mechanism is not very efficient, especially when
compared to that of a conventional bicycle. As a result, scooters
are generally not used for business commuting, sustained exercise,
or for other applications that require long-distance or high-speed
travel.
[0032] Mechanical devices that improve the efficiency of
conventional scooters are known. A typical pedal-driven scooter is
propelled forward by the operator pumping one or two platforms up
and down. Although this mechanism can be a more efficient means of
propulsion than pushing backwards against the ground, it is not
ideal because it must be translated into rotational motion to
propel the vehicle forward. These mechanisms can also cause knee
injuries because of the operator's need to reverse his or her leg's
direction of motion at the top and bottom of each pedal stroke.
Therefore, the introduction of a more efficient and lower impact
scooter propulsion system would enhance the utility of pedal driven
scooters.
[0033] With reference now to the Figures, disclosed herein is an
operator-propelled vehicle in which rotation of left and right
crank arms causes the respective left and right foot platforms to
move along an elliptical path. The term "elliptical" with regard to
"elliptical pedaling motion" or "elliptical pedaling profile" or
"elliptical path" or "elliptical motion" is intended in a broad
sense to describe a closed path of motion having a relatively
longer first axis and a relatively shorter second axis (which
extends perpendicular to the first axis as in an ellipse).
[0034] The embodiments shown and described herein are generally
symmetrical about a vertical plane extending lengthwise. Reference
numerals are generally used to designate both the "right-hand" and
"left-hand" parts, and when reference is made to one or more parts
on only one side of the apparatus, it is to be understood that
corresponding part(s) may be disposed on the opposite side of the
apparatus. The portions of the frame that are intersected by the
plane of symmetry exist individually and thus, may not have any
"opposite side" counterparts. Also, to the extent that reference is
made to forward or rearward portions of the apparatus, it is to be
understood that the drive arm assembly is movable in either of two
opposite directions.
[0035] FIG. 1 shows a general embodiment of the apparatus, or
bicycle 100. The apparatus 100 generally includes a foot link
assembly 105 movably mounted on a frame, or frame structure 110, on
which a pair of wheels (front wheel 115, rear wheel 117) are
mounted. Generally, each foot link assembly 105 is moveably mounted
to the frame 110 at its forward end where it is slideably coupled
to a foot link guide track 255 and at its rearward end where it is
rotatably coupled to the crank assembly 215.
[0036] Generally, each foot link assembly 105 includes a foot link
205, each with a foot platform 210, and a load wheel 250. The foot
platforms 210 on which the operator stands are mounted on an upper
surface of each foot link 205 near a forward end of each foot link
205. Below each foot platform 210 near the frontal section of each
foot link is a load wheel 250 that contacts a sloping foot link
guide track 255. In the embodiment depicted in FIG. 1, two foot
link guide tracks 255 run parallel to each other on either side of
the longitudinal axis of the apparatus 100 and are integral with
the frame 110. The load wheel 250 and bearings are mounted to a
fixed axle to allow nearly frictionless linear motion of the foot
links 205 along the foot link guide tracks 255 and provide
rotational freedom of the foot links 205 with respect to the foot
link guide tracks 255.
[0037] As shown in FIG. 2, during pedaling, the operator (not
shown) uses his mass in a generally downward and rearward motion as
in walking or jogging to exert a force on the foot platforms 210
and thereby, the foot links 205. This force causes the load wheel
to roll down the slope of the foot link guide track 255 towards the
rear of the apparatus 100 and rotate the crank arms 235 about the
crank arm bearing 245, turning the drive sprocket 240. As with
conventional bicycles, rotating the drive sprocket 240 causes the
rear wheel sprocket 135 to rotate because they are linked by a
chain or belt 130. It will be appreciated that the chain or belt
130 may also comprise a rotating shaft or other drive means.
Rotating the rear wheel sprocket 135 causes the rear wheel 117 to
rotate because the rear wheel sprocket is attached to the rear
wheel hub 145. Rotating the rear wheel 117 provides motive force
that enables the apparatus 100 to move along a surface. The
apparatus 100 can employ a "fixed" or "free" rear wheel, as is
known in the art. The apparatus 100 can also employ a planetary
gear hub having different gear ratios, as manufactured by Shimano,
Sturmey-Archer and others.
[0038] One feature of the apparatus, or bicycle 100 is that the
pedaling motion described above results in the operator's foot
traveling in a shape that can be described as generally elliptical.
Propulsion using an elliptical pedaling motion, as opposed to an up
and down pedaling motion or a circular pedaling motion, has the
advantage of substantially emulating a natural human running or
walking motion. Further, an elliptical pedaling motion is a simpler
and more efficient means to rotate the rear wheel 117 than is, for
example, a vertical pumping motion. Moreover, the major axis of the
ellipse in an elliptical pedaling motion can be much longer than
the stroke length of a circular or vertical pumping pedaling
motion, allowing the operator to employ a larger number of muscle
groups over a longer range of motion during the pedal stroke than
he or she could employ in a circular or up and down pedaling
motion.
[0039] As shown in FIG. 2, dashed line E depicts the generally
elliptical path that the ball of the operator's foot would take
throughout the pedaling motion. The region where the ball of the
operator's foot contacts the foot platform 210 is labeled as item
F. The power stroke during forward motion is from front-to-back and
follows the lower half of the elliptical path E. As the operator's
foot moves rearward through the power stroke of the described
elliptical pedaling motion, the heel portion falls more quickly
than does the toe portion. The return stroke during forward motion
is from back-to-front and follows the upper half of the elliptical
path E. As the operator's foot moves forward through the return
stroke of the described elliptical pedaling motion, the heel
portion of the foot rises more quickly than does the toe
portion.
[0040] As illustrated in FIG. 2, the shape of the elliptical path E
is generally defined by the following parameters: (1) the length of
the major axis A; (2) the length of the minor axis B; and (3) the
major axis angle .gamma.. The length of the major axis A is
generally equal to the stride length of the pedaling motion. The
length of the minor axis B relative to the length of major axis A
generally determines the vertical lift of the operator's foot and
angular foot plantar-flexion throughout the pedaling motion.
Decreasing the ratio of A to B increases the vertical lift of the
operator's foot and increases the angular foot plantar-flexion.
Conversely, increasing the ratio of A to B reduces the vertical
lift of the operator's foot and decreases the angular foot
plantar-flexion. As the ratio of A to B approaches infinity, the
elliptical path E collapses into a straight line of length A and
eliminates the vertical lift altogether.
[0041] The major axis angle .gamma. of the ellipse reflects the
incline angle of the pedaling motion. A major axis angle .gamma. of
zero degrees emulates natural walking or running motion on flat
ground. Increasing the major axis angle .gamma. emulates natural
walking or running motion on an incline. Foot link guide track
angle .theta. is the angle of the foot link guide track 255 from
horizontal and is generally parallel with the major axis angle
.gamma..
[0042] The three parameters that govern the shape of the generally
elliptical pedaling path E (major axis A, minor axis B, and major
axis angle .gamma., discussed above) are generally a function of
the following frame and drive mechanism dimensions: crank arm
length C, foot link length D, crank pivot offset P, operator foot
offset J, and foot link guide track angle {tilde over (.theta.)}
Crank arm length C is the distance between the center of the crank
arm bearing 245 to the foot link bearing 220. Foot link length D is
the distance between the center of the load wheel 250 and the foot
link bearing 220. Operator foot offset J is the distance from the
center of the load wheel 250 to the region where the ball of the
operator's foot contacts the foot platform, point F. Foot link
guide track angle .theta. is the angle of the foot link guide track
255 from horizontal and is generally parallel with the major axis
angle .gamma.. As discussed below, modifying these parameters will
change the elliptical pedaling profile experienced by the
operator.
[0043] As illustrated in FIGS. 1-7, the frame, or frame structure
110 of the apparatus 100 can be comprised of a variety of
materials. FIG. 1 depicts one embodiment of the apparatus 100 in
which the frame 110 is comprised of a rigid tubular metal, such as
aluminum, steel, or titanium. As illustrated in FIG. 1, the frame
structure 110 includes a lower frame member and two foot link guide
tracks 255 that, in this embodiment, also act as structural frame
members. FIG. 5 depicts an embodiment of the apparatus 100 in which
the frame 110 is comprised of sheet metal, and in this embodiment,
one frame member may be the lower portion of the frame 110 (nearest
the ground) and a second frame member may be the foot link guide
track 255 that comprises an upper portion of the frame 110. FIG. 6
depicts an embodiment of the apparatus 100 in which the frame 110
is comprised of a graphite composite, and in this embodiment,
similar to the embodiment illustrated in FIG. 5, one frame member
may be the lower portion of the frame 110 (nearest the ground) and
a second frame member may be the foot link guide track 255 that
comprises an upper portion of the frame 110, even though the two
frame members may be formed together.
[0044] Other materials may also be used to construct the frame for
the apparatus, such as plastics, alloys, other metals, etc. The
frame 110 provides the structural rigidity necessary to support the
rider while he or she is operating the apparatus 100. The frame 110
also connects the movable portions of the apparatus 100 together
into a complete system.
[0045] One of the features common to all of the proposed
embodiments of apparatus 100 is a low cross-over height frame. As
defined herein, a frame has a low cross-over height if there are no
structural frame members positioned in the operator's zone. The
operator's zone is the area of space occupied by the operator when
riding the apparatus. One embodiment of the operator's zone is
illustrated in FIG. 3, and comprises an area defined by points K
and L, and line N. Point K is the aft-most position of the load
wheel 250, point L is the mid-point of travel of the load wheel
250, and line N is formed by a line that extends between the tops
of the front wheel 115 and rear wheel 117. During operation, the
load wheel 250 travels from a forward-most position 103 to a
rear-most, or aft-most position K. As shown in FIG. 3, the
mid-point of travel for the load wheel 250 is point L, which is
half the distance of the load wheel total distance of travel 107.
Put differently, the load wheel total distance of travel 107 is the
maximum stride length that an operator would be able to achieve,
and may range from about 14 inches to about 26 inches. As shown in
FIG. 3, the operator's zone extends from line N upwards, and is
bounded by two substantially vertical lines that extend from points
K and
[0046] L.
[0047] It will be appreciated that the operator's zone may extend
further forward or backward depending on the amount of forward and
rearward movement the operator must undertake when operating a
specific embodiment of the apparatus. For example, for some
embodiments, point L may be defined as the location of the ball of
the operator's foot when it is located at the forward extreme of
the pedal stroke (point 103) on the foot platform 210, and point K
may be defined as the heel of the operator's foot when it is on the
foot platform 210 and the load wheel 250 is at its aft-most
position. Similarly, it may be appreciated that for embodiments
where the front wheel 115 and the rear wheel 117 are small (have
diameters less than 20 inches), line N may be set at a given
distance off of the ground (approximately 26 inches) rather than
formed by a line that extends between the tops of the front wheel
115 and rear wheel 117.
[0048] FIGS. 1, 4, 5, 6, 7, 12, 13, and 14 depict several different
proposed embodiments, all of which have low cross-over height
frames 110. As shown in FIG. 3, generally, the frame 110 includes
truss members 112 and two foot link guide tracks 255. However, some
frame 110 embodiments, like those shown in FIGS. 5 and 6, do not
include truss members 112. Moreover, the foot link guide tracks 255
may be an integral component of the frame, as shown, for example,
in FIGS. 4-6. The individual guide tracks may also be integrated
together to form a single guide track, as depicted in FIG. 14.
[0049] Low cross-over height frames 110 are safer and more
convenient to use than conventional upright step-cycle or bicycle
frames. The low cross-over height design is safer because there are
no support structures in the operator's zone that could cause
injury during a fall or during riding. These frames are also more
stable to ride because they have a lower center of gravity. The low
cross-over height design also makes the apparatus 100 easier and
safer to mount and dismount because there are no support structures
in the operator's zone to step over or around when mounting or
dismounting. In addition, the low cross-over height makes the
apparatus 100 easier to maneuver in tight spaces because it enables
the operator to easily step across the apparatus 100, which
facilitates moving the apparatus 100 into and out of storage areas,
trains, buildings, and the like.
[0050] One consideration when designing low crossover-height frames
110 is stiffness in bending. Unlike conventional frames, a low
cross-over height frame 110 does not include a structural member
above the plane of the top of the wheels to provide stiffness in
bending. Because the frame 110 must support the dynamic weight of
the operator during riding, stiffness in bending is important not
only to prevent frame member failure, but also to improve pedaling
efficiency and handling.
[0051] The proposed embodiments have been designed to provide
sufficient frame 110 stiffness in bending. For example, the frame
100 design in FIG. 4 has a stiffness of approximately 2500 lbf/in.
When the embodiment depicted in FIG. 4 is subjected to a 200 pound
load in the center of the foot link guide tracks 255, the frame 110
will deflect no more than about 0.08 inches, thereby minimizing the
negative effects of frame flexing discussed above. This improved
stiffness in bending is achieved by several features contained in
the low cross-over height frame 110, including incorporation of the
foot link guide tracks 255 into the frame 110 as frame members, and
the use of truss members 112 to enhance stiffness.
[0052] As shown in several of the Figures, embodiments of the
apparatus 100 include a steering mechanism 120 that may comprise
handlebars 119, a steering wheel (not shown), or other steering
means. The steering mechanism 120 can be mounted upon a fixed or
adjustable steering extender 125 that extends upward from the frame
110. The steering mechanism 120 can be telescopically adjustable,
as well as adjustable forward and backward, and can incorporate a
pivot to provide rotational adjustability. One feature is that an
adjustable steering mechanism will permit easy and safe use by a
variety of operators having different heights and arm
dimensions.
[0053] FIG. 11 depicts a detailed view of one embodiment of a
telescoping steering mechanism. In this embodiment, the steering
extender 125 is held by a steering extender sleeve 126. The inside
diameter of the steering extender sleeve 126 is larger than the
outside diameter of both the front fork steer tube 127 and the
steering extender 125. In this embodiment, the front fork steer
tube 127 has been inserted into the bottom of the steering extender
sleeve 126 and is clamped to it by means of one or more fasteners
128, such as a bolt and nut, pin, clip or other means. In addition,
the steering extender 125 is inserted into the top of the steering
extender sleeve 126 and is clamped to it by means of another
fastener 128. The height of the steering mechanism 120 can be
adjusted by varying the position where the steering extender sleeve
126 clamps to the steering extender 125. FIGS. 13A-B depict a
steering tube assembly with both translational and rotational
adjustability.
[0054] As shown in FIGS. 1, 4, and 6, embodiments of the apparatus
100 can also incorporate a rear wheel cover 190. The purpose of the
rear wheel cover 190 is to prevent the operator's legs, feet,
clothing, and other objects from contacting the rear wheel 117. The
cover 190 can be made from metal, plastic, graphite composite,
fiberglass, or other materials. It can be attached to the frame by
bolts, welds, brazes, or other methods, or it can be an integrated
part of the frame 110 as shown in FIG. 6. To facilitate
transporting and maneuvering the apparatus 100 while walking, a
handle 191 can be attached to, or incorporated into, the rear wheel
cover 190, or a handle 191 can be attached to, or incorporated
into, the frame 110 and protrude through an opening in the rear
wheel cover 190.
[0055] FIG. 1 depicts a rear wheel cover 190 with a handle 191. The
handle 191 is integrated into the rear wheel cover 190 and the rear
wheel cover 190 is bolted to the frame 110. FIG. 4 depicts a rear
wheel cover 190 without a handle that is bolted to the frame 110.
FIG. 6 depicts a rear wheel cover 190 without a handle that is
integrated into a carbon fiber frame 110.
[0056] Referring now to FIGS. 10A-B, each foot link 205 can be
laterally constrained onto its respective foot link guide track 255
in a variety of ways. FIGS. 10A and 10B, which is a sectional view
about section M-M shown in FIG. 10A, and FIGS. 10C and 10F depict
one method of laterally constraining the foot link 205. In this
method, the load wheel 250 has a V-groove 305 that mates to the
counterpart geometry of a substantially diamond-shaped foot link
guide track 255. The top of the foot link guide track 255 fits into
the center of the groove of the load wheel 305, thereby laterally
constraining the foot link 205.
[0057] FIGS. 10D, 10i, 10J, and 10K depict a similar mechanism for
laterally constraining a foot link 205 onto a round or
tubular-shaped foot link guide track 255. In these embodiments, the
contact surface of the load wheel 250 has a concave shape that
mates with the counterpart geometry of the round foot link guide
track 255. The top of the foot link guide track 255 aligns with the
center of the load wheel 250 and the foot link 205 is laterally
constrained onto the foot link guide track 255 by the interface of
the concave load wheel 205 and the round tube comprising the foot
link guide track 255.
[0058] FIG. 10E depicts another method of laterally constraining a
foot link 205 onto a foot link guide track 255. This embodiment
uses a load wheel carrier 271 that is attached to each foot link
205. In the depicted embodiment, the load wheel carrier 271 holds
two load wheels 250. The load wheels 250 are set into the load
wheel carrier 271 at opposing angles. The interaction of each load
wheel 250 with the foot link guide track 255 results in the lateral
constraint of the attached foot link 205. Although a diamond shaped
foot link guide track 255 is depicted in FIG. 10E, this method
could also be used with round, tubular, or similarly shaped foot
link guide tracks 255.
[0059] The lateral constraining methods discussed above are
intended to prevent the foot link assembly from laterally
disengaging with, or "falling off" of, the foot link guide track
255. The list is not intended to be exhaustive. Its purpose is only
to illustrate a few of the many methods of restraining the foot
links 205 in the lateral direction.
[0060] In addition to lateral constraint, each foot link 205 may
also be retained in the normal direction (a direction generally
perpendicular to the foot link guide track 255). That is, each foot
link 205 may be restrained from "jumping off" the foot link guide
track 255. The foot links 205 could be subject to disengaging in
the normal direction whenever, for instance, the apparatus 100
travels over sharply undulating or rough terrain, or strikes an
obstacle. The retention methods discussed below are intended to
prevent the foot link assembly from disengaging with the foot link
guide track 255 in the normal direction during operation of the
apparatus 100. The list is not intended to be exhaustive. Its
purpose is only to illustrate a few of the many methods of
restraining the foot links 205 in the normal direction.
[0061] FIGS. 10A, 10B, 10C, 10D, 10E, 10F, and 10i depict a method
of normal retention in which one or more retaining links 605 holds
a retaining member 610 underneath a feature of the foot link guide
track 255, or the foot link guide track 255 itself. The interaction
of the retaining member 610 with the foot link guide track 255 or a
feature on the foot link guide track 255 prevents the load wheel
250 from disconnecting with the foot link guide track 255.
[0062] There are many ways to vary this method of retention,
including changing the shape, size, number or other characteristic
of the retaining links 605, changing the shape, size, number, or
other characteristic of the retaining member 610, changing the
shape, size, or number of foot link guide tracks 255, or changing
the shape, size, number, or other characteristics of features
connected to the foot link guide track 255 or frame 110. For
example, FIGS. 10F and 10i depict just two kinds of the many
features that could be attached to the foot link guide tracks 255
to facilitate retention. FIG. 10F depicts an eave-like structure,
and FIG. 10i depicts a rail-like structure. A variety of other
features could be employed for this purpose. Similarly, FIGS. 10A
and 10D depict different shapes of the retaining member 610. FIG.
10A shows a round member and FIG. 10D shows a cylindrical member.
In fact, the retaining member 610 could be any manner of bar, pin,
wheel, cable, or other mechanism that could serve to prevent the
load wheel 250 from disengaging with the guide track 255.
[0063] Moreover, the retaining link 605 or links can be designed to
either hold the retaining member 610 at a fixed distance from the
load wheel, or to allow for adjustment of that distance. FIGS. 10C,
10D and 10E depict retaining links 605 that hold the retaining
member 610 at a fixed distance. FIG. 10B depicts one embodiment of
a retaining link 605 in which a preloaded spring mechanism 630
holds the retaining member 610 in contact with the guide track 255
throughout the pedal stroke. The preloaded force can be adjusted by
rotating the set screws 615 and 620. This same system could also be
used to establish and then adjust a gap between the retaining
member 610 and the guide track 255, thereby preventing the
retaining member from contacting the guide track 255 except when
needed to prevent the load wheel from disengaging with the guide
track 255. Such a gap can be set by rotating the set screws 615 and
620. The gap can then be adjusted over time in the same manner to
compensate for wear of the load wheel 250. Again, the depictions
described herein are meant to be illustrative only, and the
apparatus 100 may include any number of variations and embodiments
relating to retention of the load wheel 250 to the foot link guide
track 255.
[0064] FIGS. 10G, 10H, 10J and 10K illustrate several embodiments
of an axle bar retention system. In this system, a retention member
is passed through the axle of the load wheel such that it protrudes
from one or both ends of the axle. The load wheel is constrained in
the normal direction by the interface of this retention member and
a structure attached to the frame 110. The retention member can be
any manner of pin, bolt, bar, or the like.
[0065] For example, as shown in FIGS. 10G and 10H, the axle
retention member 1010 protrudes from both sides of the load wheel
250. In FIG. 10G, each end of the axle retention member 1010 passes
through a slot 285 formed in the foot link guide track 255. The
interaction between the axle retention member 1010 and the slot 285
prevents the foot link 205 from disengaging with the foot link
guide track 255 in the normal direction. Similarly, in FIG. 10H,
each end of the axle retention member 1010 is positioned below a
ledge 280 included in the foot link guide track 255. The
interaction between the axle retention member 1010 and the ledge
280 prevents the foot link 205 from disengaging with the foot link
guide track 255 in the normal direction.
[0066] In FIGS. 10J and 10K, only one end of the axle retention
member 1010 protrudes from the load wheel 250. In FIG. 10J, the
protruding end of the axle retention member 1010 has a hole drilled
through it. The hole captures a securing member 287 that is
connected to the foot link guide tracks 255 or another part of the
frame 110. The securing member 287 can be any manner of rod, cable,
bar, or similar item. Similarly, in FIG. 10K, the axle retention
member 1010 is slotted to capture a securing member 287 that is
connected to the foot link guide tracks 255 or another part of the
frame 110. In both embodiments, the interaction between the
retention member 1010 and the securing member 287 prevents the foot
link 205 from disengaging with the foot link guide track 255 in the
normal direction.
[0067] FIG. 10L depicts an alternative embodiment that provides
both lateral and normal constraint. In this embodiment, the load
wheel 250 has been replaced by a linear bearing 1030. The linear
bearing 1030 is free to slide along the foot link guide track 255,
however the lower portion 1020 of the linear bearing 1030 captures
the foot link guide track 255, thereby preventing the foot link 205
from disengaging from the foot link guide track 255 in the lateral
or normal direction.
[0068] As discussed above, there are several ways to modify the
elliptical pedaling profile of the apparatus 100. One method is to
change the location of the ball of the operator's foot (identified
as location F in FIGS. 2, and 9A-B) with respect to the load wheel
250 or the first end of each foot link 205. Referring now to FIGS.
9A-B, the first end of the foot link 205 is the end of the foot
link 205 that is directly adjacent to the load wheel 250, and the
second end of the foot link 205 is the end of the foot link 205
that is directly adjacent to the foot link bearing 220 (shown in
FIG. 1). Modifying the location of the operator's foot 121 relative
to the load wheel 250 or the first end of the foot link 205 changes
the operator foot offset (identified as distance J in FIGS. 2 and
9A-B). To achieve a flatter and more eccentric pedaling profile,
the operator can position his or her foot closer to the first end
of each foot link 205. Alternatively, by positioning his or her
foot further away from the first end of the foot link 205, the
operator can create a more circular and less eccentric pedaling
profile. Because the distance between the operator's foot 121 and
the load wheel 250 or first end of each foot link 205 influences
the pedaling profile, the repeatability of adjustments to this
distance ensures that the operator can experience the desired
pedaling profile.
[0069] There are a variety of ways to enable the operator to
repeatably modify the position of his or her foot relative to the
first end of the foot link 205. FIG. 9A depicts one method. In this
embodiment, each foot platform designates a single position for an
operator's foot 121. The interface between each foot platform 210
and its respective foot link 205 is adjustable such that the foot
platforms 210 can be attached onto the foot links 205 at different
distances from the first ends of the foot links 205. The attachment
method in this embodiment is a pair of releasable clamps 905 that
connect each foot platform 210 to its respective foot link 205.
This mechanism enables the operator to adjust each foot platform to
achieve a repeatable placement of his or her foot relative to the
first end of each foot link. In addition, each foot platform 210
could also include one or more securing elements 910 such as ridges
or straps to prevent the operator's foot 121 from unintentionally
disengaging from the foot platform 210. It will be appreciated that
the securing elements 910 can take many equivalent forms, such as
baskets, clips, bumps, cleats, or the like. In addition, index
lines (not shown) could be incorporated into the foot link 205 to
facilitate more accurate and repeatable positioning of the foot
platforms 210 relative to the first end of the foot link 205.
[0070] There are additional ways to create a repeatable adjustable
interface between the foot platforms 210 and foot links 205. For
example, a repeatable interface could also be created by a series
of mounting holes in the foot links 205 and/or the foot platforms
210 that allow for different mounting positions of the foot
platform 210 along the foot link 205.
[0071] FIG. 9B depicts an alternative method for enabling the
operator to repeatably change the position of his or her foot
relative to the first end of each foot link 205. In this
embodiment, the foot platform 210 is large enough to permit the
operator to change the position of his or her foot relative to the
first end of the foot link 205 without moving the foot platform
210. The foot platform 210 includes one or more foot locators 920
to enable the repeatable use of the various foot positions on the
foot platform 210. The foot locators 920 could include features
such as cleats, bumps, ridges, or the like. Each foot platform 210
could also include securing elements 910 as discussed in connection
with FIG. 9A.
[0072] As discussed above, another method for adjusting the
pedaling profile is modifying the length of the crank arms 235. As
shown in FIGS. 1 and 8, the crank assembly 215 includes a crank
extender 230 rotatably connected to the second end of the foot link
205 at the foot link bearing 220. The crank assembly 215 also
includes a crank drive arm 235 rotatably connected at the crank arm
bearing 245 to a drive sprocket 240. As shown in FIG. 2, Circle R,
shown as a dashed line, is generated by rotating the crank assembly
215 around the crank arm bearing 245. The distance between the
center of the crank arm bearing 245 and the center of the foot link
bearing 220 is crank arm length C. Shortening crank arm length C
will shorten the stride length A. Correspondingly, increasing crank
arm length C will increase stride length A. Therefore, adjustments
in crank arm length C can be made to modify stride length A to
allow operators of different stature to adjust the apparatus 100 to
suit their individual dimensions.
[0073] There are many ways to modify the length of the crank arms
235. FIG. 8 depicts one method for making the crank assembly 215
adjustable. This method employs a slot-bolt assembly 810 where the
crank extender 230 includes a slot 270 and the crank drive arm 235
includes apertures configured to receive crank fasteners 275 that
can locate the crank drive arm 235 at any position along slot 270.
The crank extender 230 can thereby telescope, or adjust its length
with respect to the crank drive arm 235.
[0074] There are additional ways to make the crank assembly 215
adjustable. For example, the slot-bolt assembly 810 discussed above
can be replaced by a clamp with pins that can clamp the crank
extender 230 to the crank drive arm 235 at various positions.
Another embodiment may make the crank assembly 215 adjustable by
incorporating a series of holes in the crank extender 230 or the
crank drive arm 235, or both. In such an embodiment, the length of
the crank drive 235 arms may be modified by changing which holes
are used to fasten the crank extender 230 to the crank drive arm
235.
[0075] As discussed above, and again with reference to FIG. 2,
crank arm length C is a significant factor that determines major
axis length A, which approximately equals the stride length of a
given pedaling profile. For a rider of average height and body
dimensions, as the stride length shrinks below approximately 17
inches, the rider's ability to transfer power to the apparatus 100
for purposes of acceleration and climbing becomes reduced. As a
result, while embodiments with stride lengths generally less than
about 17 inches may be appropriate for a small percentage of
operators, the vast majority of riders will desire stride lengths
longer than 17 inches to achieve sufficient pedaling efficiency.
Embodiments of the apparatus 100 presented herein can accommodate
stride lengths in excess of 23 inches.
[0076] As the stride length increases, it may be desirable to
increase the wheelbase W as shown in FIG. 2. For a low cross-over
height frame 110, the longer the wheelbase W, the more difficult it
is to maintain an appropriate level of bending stiffness, yet a
wheelbase W that is significantly longer than conventional bicycles
is desirable. For example, a conventional bicycle may have a
wheelbase of about 40 inches, but embodiments of the present
invention may have a wheelbase W that may range from about 55
inches to about 65 inches. As discussed above, embodiments of the
apparatus 100 include a frame 110 having a sufficient bending
stiffness to accommodate a stride length beyond 23 inches.
[0077] Alternative embodiments of the apparatus 100 can incorporate
additional features, such as a direct drive propulsion mechanism,
adjustable guide tracks, and/or foldability. FIG. 12 depicts an
embodiment of the apparatus that employs a direct drive propulsion
system. In this embodiment, the crank arms 235 are connected
directly to the hub 1210 by means of bearings (not shown) mounted
in the frame 110, through which passes a linkage from each crank
arm 235 to the hub 1210. This alternative embodiment alleviates the
need for a chain and sprockets. This embodiment could incorporate a
gearing system in the crank-to-hub-wheel linkage that could allow
the rear wheel to rotate more quickly than the crank arms. Such a
gearing system could provide a fixed input-output ratio, or could
allow for one of a series of gears to be selected by the operator.
In addition, the rear wheel 117 could be enlarged to allow the
operator to achieve a greater rate of speed for each completed
pedal stroke.
[0078] FIG. 7 depicts a low cross-over height frame 110 with
adjustable foot link guide tracks 255. The forward end of each foot
link guide track 255 is attached to a foot link guide track support
705 by the use of a rotary bearing 710, so that the forward end of
the foot link guide track 255 can rotate about the foot link guide
track support 705. Each foot link guide track support 705 is
attached to its respective side of a collar 715 by the use of a
bolt and low friction washers, or other suitable means. The collar
715 can be clamped to the downtube 725 at various locations by
means of bolts or other fasteners. The low friction washers allow
each foot link guide track support 705 to rotate about the bolt.
The rearward or second end of each foot link guide track 255 is
attached to the frame by the use of a rotary bearing 720.
Unclamping the collar 715 allows the operator to slide the collar
715 along the downtube 725, thereby adjusting the angle of the foot
link guide tracks 255. As discussed below, changing the angle of
the foot link guide tracks 255 modifies the elliptical pedaling
profile experienced by the operator.
[0079] FIGS. 13A and 13B depict an embodiment of the apparatus 100
that can be folded to facilitate transport or storage in small
spaces. In this embodiment of a foldable apparatus 100, the
apparatus 100 is folded according to following procedure. First,
the foot link retainer 610 on each foot link assembly 105 is
released from the guide track 255 by removing a pin (not shown).
Next, each foot link assembly 105 is rotated about its respective
foot link bearing 220 towards the rear wheel 117 approximately one
hundred eighty (180) degrees. Next, the coupling 1340 on each side
of the apparatus is released. Each foot link guide track 255 is
then rotated downwards about guide track pivot 1330. Next, the
crank assembly 215 is rotated forward about pivot 1320 until the
rear wheel 117 passes through the frame 110. Next, each guide track
255 is rotated upwards about guide track pivot 1330. Then the crank
assembly 215 is rotated until the right crank arm 235 points to the
rear, as depicted in FIG. 13B. At that point, each foot link 205
may be strapped to the adjacent crank arm extender 230. The right
foot link assembly 105 is then positioned on top of the front fork
127 and the left foot link assembly 105 is positioned on top of the
axle of the rear wheel 117. Next, the steering assembly pivot 1310
is released and the steering extender sleeve 126 is rotated
rearward. The steering extender sleeve 126 is then locked in place
at steering assembly pivot 1310 as depicted in FIG. 13B. Once
locked, the steering extender sleeve 126 may be used as a handle to
carry or help direct the path of travel for the folded apparatus
100. FIG. 13B depicts the results of following the folding
procedure described above.
[0080] In addition, the apparatus 100 can include gearing. Gearing
can be implemented through techniques known in the art, including a
series of different sized sprockets attached to the rear wheel 117
and selected by a derailleur, or a single rear sprocket connected
to a hub that contains a series of gears inside of it which enable
the hub to produce a variety of input-to-output ratios. This
embodiment could incorporate techniques known in the art to permit
the operator to select gears. This could include mounting a shift
lever on the steering mechanism 120 as is known in the art. The
apparatus 100 can also include a fixed gear system with no
freewheel on the rear wheel 117.
[0081] The apparatus can also include mechanisms to retard motion,
such as rim or disc braking systems known in the art. These
mechanisms can be located on the front and/or rear wheels. The
braking mechanisms can be actuated by, for example, a hinged handle
or other structure mounted on the handlebars to which the brake
cables or some other mechanism are connected, as is known in the
art. In addition, the apparatus can include other attributes that
are commonly incorporated onto other human powered vehicles, such
as reflectors, lights, bottle cages, etc.
[0082] It is to be noticed that the term "comprising", used in the
claims, should not be interpreted as being limitative to the means
listed thereafter. Thus, the scope of the expression "a device
comprising means A and B" should not be limited to devices
consisting only of components A and B. It means that with respect
to the present invention, the only relevant components of the
device are A and B. Moreover, the components A and B should not be
limited to a specific relationship or form; instead, they can be
integrated together into a single structure or can operate
independently.
[0083] Similarly, it is to be noticed that the term "coupled", also
used in the claims, should not be interpreted as being limitative
to direct connections only. Thus, the scope of the expression "a
device A coupled to a device B" should not be limited to devices or
systems wherein device A is directly connected to device B. It
means that there exists a path between A and B which may be a path
including other devices or means. In addition, "coupled" does not
necessarily mean "in a fixed position or relationship" as "coupled"
may include a moveable, rotatable or other type of connection that
allows relative movement between A and B. Finally, "coupled" may
also include "integral" where device A and device B are fabricated
as an integral component or single structure.
[0084] Thus, it is seen that a bicycle is provided. One skilled in
the art will appreciate that the bicycle of the present invention
can be practiced by other than the above-described embodiments,
which are presented in this description for purposes of
illustration and not of limitation. The specification and drawings
are not intended to limit the exclusionary scope of this patent
document. It is noted that various equivalents for the particular
embodiments discussed in this description may practice the
invention as well. That is, while the bicycle has been described in
conjunction with specific embodiments, it is evident that many
alternatives, modifications, permutations and variations will
become apparent to those of ordinary skill in the art in light of
the foregoing description. Accordingly, it is intended that the
bicycle embrace all such alternatives, modifications and variations
as fall within the scope of the appended claims.
* * * * *