Note: Descriptions are shown in the official language in which they were submitted.
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A ZERO ROLL SUSPENSION SYSTEM
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of pending U.S. Patent
Application Serial No. 09/307,628 entitled "A Zero Roll Suspension System",
filed on May 7, 1999 and herein incorporated by rE?ference in its entirety.
S FIELD OF THE INVENTI~DN
The present invention relates genera:fly to a suspension system
for vehicles, and more particularly to a suspension system for controlling the
lateral roll of a vehicle during cornering and additionally for controlling
1 0 fore-aft movement, or pitch, commonly described as vehicle rise and squat,
caused by the inertia of the vehicle during acceleration and deceleration.
BACKGROUND OF THE INVIBNTION
I S Vehicle suspension characteristics generally determine ride
height, spring rates, caster, camber, toe-in, braking dive, acceleration
squat,
and cornering roll. Anti-roll suspension systems .are those in which forces
that tend to cause roll of the vehicle body with respect to the wheels about a
longitudinal axis are resisted by forces acting through or on the suspension
2 0 system. Vehicle suspension systems having anti-roll characteristics are
generally either 'active' suspensions using hydraulic actuators to adjust
suspension characteristics in response to sensed lateral acceleration, or more
commonly, suspensions that incorporate devices such as anti-roll or
stabilizer bars that have fixed suspension characteristics.
2S
Typical of an 'active' suspension sysfiem is U.S. Patent No.
4,865,347 for Actively Controlled Suspension System Anti-Roll Control,
issued to Fukushima et. al. on September 12, 1989, which describes a
suspension system having an anti-roll control loop in which the gain is
3 0 adjusted depending on the speed of the vehicle. The '347 suspension system
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utilizes acceleration sensors to detect lateral acceleration and pressure
control
valves to adjust hydraulic cylinders which vary the suspension character-
istics according to the speed of the vehicle.
U.S. Patent No. 4, 948,164 for Actively Controlled Suspension
System with Compensation of Delay in Phase in Control System, issued to
Hano et. al. on August 14, 1990, describes an actively controlled suspension
system which can compensate for phase delay caused in a control system and
load condition on the vehicle. The active suspension system described in the
1 0 '164 patent employs a plurality of acceleration :>ensors for detecting
lateral
acceleration. Based on the sensed acceleration, anti-rolling suspension
control signals are produced for controlling suspension characteristics of
left
and right-side suspension systems.
1 5 U.S. Patent No. 5,114,177 for Anti-Rolling Controlling System
for Automotive Active Suspension System With Road Friction Dependent
Variable Control Characteristics, issued to Fukunaga on May 19, 1992, is
directed to an active anti-rolling suspension control system having a means
for monitoring road friction conditions and a ameans for distributing xolling
2 0 moment between front suspension systems and rear suspension systems.
U.S. Patent No. 3,820,812 for Vehicle Suspension Systems,
issued to Stubbs, et. al. on June 28, 1974, is for an active anti-roll
suspension
control system for four-wheeled road vehicles that have variable-length
2 5 hydraulic struts acting in series with the front springs controlled by a
control
unit sensitive to lateral acceleration. The rear suspension anti-roll system
is
applied by hydraulic cylinders acting on the rear suspension independently of
the rear springs and controlled by the control 'units for the corresponding
front struts.
Active anti-roll suspension systems such as those described
above have the disadvantage of being relatively complex and have proved
too costly to implement in most vehicles. Anti-roll suspension systems with
fixed suspension characteristics, in which the .anti-roll damping forces do
not
3 5 vary with speed or direction, are also described in the prior art. U.S.
Patent
No. 4,573,702 for Anti-Pitch Suspension, issued to Klem on March 4; 1986, for
example, is for a vehicle suspension system designed to utilize lateral move-
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ment of the body of the vehicle relative to the wheels in order to control the
sway or roll of the vehicle body. The '702 suspension system utilizes springs
of various types to create an additional means to increase compression or
extension of conventional suspension pieces. The principle of the
invention may also be used to control dive during braking or squat during
acceleration.
U.S. Patent No. 5,074,582 for Vehicle Suspension System, issued
to Parsons on July 5, 1990, depicts a roll frame pivotally mounted transverse
1 0 of the vehicle, the roll frame having an arm at either end and a wishbone
pivotally supported on each arm. Each wishbone forms part of a linkage for
supporting a wheel of the vehicle.
U.S. Patent No. 4,143,887 for Independent Rear Suspension
1 5 System, issued to Williams on December 21, 1977, depicts a rear suspension
utilizing a torsion bar mounted between oppo;>itely disposed wheel carriers
and cooperable with laterally extending control arms for providing roll steer
characteristics for the rear wheels.
2 0 U.S: Patent Nos. 5,388,855 and 5,193;843 both entitled
Suspension System of a Vehicle and both issued to Yamamoto on May 24,
1994 and March 16, 1993; respectively, are directed to a double pivot type
suspension system to allow a wheel located radially inward in relation to a
turning circle to be turned more sharply than ;a wheel located radially
2 5 outward in relation to the turning circle.
U.S. Patent No. 5,415,427 for Wheel Suspension System, issued
to Sommerer et. al. on May 16, 1995, depicts a suspension system comprising
a wheel carrier supported on the body side by way of a spring strut. The
3 0 wheel carrier is guided by two individual Iinks forming an upper pivotal
connection and a lower pivotal connection between the wheel and the
vehicle body. The pivotal connections are arranged at different angles with
respect to the wheel contact plane and, viewed from the top, are arranged to
be crossed with respect to one another:
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U.S. Patent No. 4,406,479 for Veliicte Suspension Incorporating
Cross-Over Links, issued to Chalmers on September 27, 1983, is directed to a
suspension system for a vehicle having a pair of torque rods splayed or
outwardly angled relative to the longitudina~axis of the vehicle in which the
torque rods cross each other as viewed from the top and are flexibly
connected to the vehicle chassis at their inner ends.
Although springs and anti-roll bars described in the prior art
reduce cornering roll, there is a trade-off between reduction in roll and the
1 0 smoothness of the ride. Spring and shock rates that increase the
smoothness
of the ride counteract the effect of the conventional anti-roll devices
described in the prior art. Moreover, such anti-roll devices do not
compensate for variations in weight distribution of the vehicle which can
also significantly affect rolling characteristics.
(3BTECTS AND SUMMARY OF 'CHE INVENTION
It is an object of the present invention to provide an economical
anti-roll suspension system for vehicles that reduces cornering roll,
2 0 acceleration squat and braking dive to nearly zero by using crossed
mechanical linkages that cancel rolling moments at each wheel.
It is another object of the preseni: invention to provide an
improved anti-roll suspension system that is independent of the weight
2 5 distribution of the vehicle.
It is yet another object of the present invention to provide an
anti-roll suspension system that can be easily modified to allow some frame/
body roll out of a corner such that the tops of alI wheels are cambered into
3 0 the corner to improve cornering grip.
It is a further object of the present invention to provide an anti-
roll suspension system that can be applied only to the front wheels of a
vehicle having a solid axle suspension in order to achieve reduced body roll.
It is a further object of the present invention to provide an
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anti-roll suspension system that does not require the use of a stabilizer or
anti-roll bar.
According to one embodiment of the present invention, a zero
roll suspension system is proposed for a vehicle including a vehicle frame
and a wheel assembly having an axis of rotation about which a wheel of said
wheel assembly rotates.
The suspension system includes a first crossing member and a
1 0 second crossing member which axe adapted to be fixed to the wheel assembly
and the vehicle frame so as to cross one another in superposition.
The present invention is directed towards an anti-roll apparatus
for vehicles that uses the load moment on the wheel of the vehicle, which is
1 5 generated by the cornering force at the point of contact between the tire
and
the road, to cancel out the rolling moment in t:he vehicle frame and body.
The device described herein may be utilized at each independently
suspended wheel assembly of a vehicle.
2 0 Conventional suspension systems have upper and lower
linkages which transmit forces from the wheel to the vehicle body, and
generally increase the roll of the vehicle durin~; cornering. The present
invention takes advantage of the fact that both the wheel moment and the
body roll moment are proportional to the cornering force. By orienting the
2 5 suspension links such that the links cross each other, the wheel load
moment opposes the rolling moment of the vehicle. The anti-roll effect of
the present invention can be increased or decreased by changing the vertical
distances between the linkage attachment points on the vehicle body and the
wheel, as will be hereinafter described.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a partial cross-sectional view of a zero roll suspension
system having perpendicular rotational and crossing axes, according to one
3 5 embodiment of the present invention.
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Fig. 2 is a partial cross-sectional view of a zero roll suspension
system having a pass through opening in one of the crossed links, according
to another embodiment of the present invention.
Fig. 2a partial perspective view of a linking mechanism,
according to the zero roll suspension system of Fig. 2.
Fig. 3 is a top, partial cross-sectional plan view of a zero roll
suspension system according to the zero roll suspension system of Fig. 2.
Fig. 4 is a partial cross-sectional view of the forces which interact
in the zero roll suspension system of Fig. 1.
Fig. 5 illustrates a free body diagram of the forces which interact
1 5 in the zero roll suspension system of Fig. 1.
Figs. 6a and 6b are partial cross-sectional views of an embodi-
ment of the present invention implemented on a front wheel drive vehicle.
2 0 Figs. 7a and 7b are partial cross-sectional views of an embodi-
ment of the present invention implemented an a rear wheel drive vehicle.
Figs. 8a and 8b are partial cross-sectional views of an embodi-
ment of the present invention implemented on a four wheel drive vehicle.
Figs 9a and 9b are partial cross-sectional views of an embodi-
ment of the present invention implemented in a vehicle having in hub
motors instead of a drive shaft.
3 0 Fig. 10 is a partial cross-sectional view of a zero roll suspension
system implemented in a rear wheel drive vehicle in which the drive shaft
acts as one of the crossed links, according to another embodiment of the
present invention.
3 5 Fig. 11 is a top, partial cross-sectional plan view of a zero roll
suspension system according to another embodiment of the present
invention in which the drive shaft acts as ones of the crossed links.
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Figs. 12a and 12b are schematic views of an embodiment of the
present invention implemented on a rear wheel drive vehicle in which the
drive shaft acts as one of the crossed links.
Fig. 13 is a partial cross-sectional view of a zero roll suspension
system having parallel rotational and crossing axes, according to another
embodiment of the present invention.
Fig. 14 is a top, partial cross-sectional plan view of a zero roll
1 0 suspension system according to the embodiment depicted in Fig. 13.
Fig. 15 is a partial cross-sectional view of a zero roll suspension
system having flexible, mufti-layered composiite elongated members,
according to another embodiment of the present invention.
IS
Fig. 16 is a partial cross-sectional view of a zero roll suspension
system having variable length elongated members, according to another
embodiment of the present invention.
2 0 Fig. 17 is a top, partial cross-sectional plan view of a zero roll
suspension system according to another embodiment of the present
invention in which a toe bar is incorporated.
DETAILED DESCRIPTION OF THE PRE1?ERRED EMBODIMENTS
Referring to Fig. 1, a suspension ;>ystem for controlling the
lateral roll of a vehicle during cornering, acco~°ding to one
embodiment of
the present invention, is generally designated by the reference numeral 10.
The suspension system 10 is adapted to be received by the body of a vehicle,
3 0 such as an automobile frame 12, having a wheel assembly 14, a spindle 16,
~
kingpin 18, and a spring and shock absorber assembly 20. The wheel
assembly 14 has an axis of rotation R about which a wheel of the wheel
assembly 14 rotates. The vehicle frame 12 may be of any automobile make or
model, such as but not limited to a pick-up truck, an utility truck, a three-
3 5 wheeled vehicle or a four-wheeled or more wheeled vehicle that tends to
rotate or roll during cornering.
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The spring and shock absorber assembly 20 provides vertical
support for the wheel assembly 14 and the vehicle frame 12 while, as is
commonly known, the wheel assembly 14, the spindle 16 and the kingpin 18
are each integrally connected in a conventional manner so as to provide for
structural stability and control of the vehicle. The present embodiment of
Fig. 1 includes a crossed linking mechanism 22: which acts to connect the
wheel assembly 14 to the vehicle body 12. While the suspension system 10
will function with most vehicles, it should be readily apparent that the
actual
shape and size of various components will depend upon the size and weight
1 0 of the associated vehicle. It should be readily .apparent that while one
linking
mechanism 22 has been described, more than one linking mechanism may
be alternatively substituted without departing from the broader aspects of the
present invention, as will be described later.
1 5 Referring still to Fig. 1, the linking mechanism 22 of the present
invention reverses the moment, preferably at the wheel, to oppose the
rolling moment of the vehicle body 12 during cornering. The linking
mechanism 22 includes at least a first elongated member 24 and a second
elongated- member 26 which are oriented so as. to cross each other in
2 0 substantially parallel planes along a crossing axis C. It will be readily
apparent that the crossing axis C is not an axis, which defines predetermined,
fixed points along either the first elongated me?tuber 24 or the second
elongated member 26. The crossing axis C as seen in Fig. 1, may initially lie
above, below or on the rotational axis R , and will shift from this initial
2 5 position during operation of the present invention. Moreover, although
Fig.
1 illustrates the first elongated member 24 and the second elongated member
26 crossing one another in substantially parallel planes as viewed
horizontally , the present invention is not limited in this regard as the
first
elongated member 24 and the second elongated member 26 may have any
3 0 planar relationship between one another provided that when viewed
horizontally, the first elongated member 24 and the second elongated
member 2b cross in superposition.
As shown in Fig. 1, each elongated member, 24 and 2b
3 5 respectively, are additionally oriented so as to cross the rotational axis
R of
the wheel assembly 14. The present invention, however, is not limited in
this regard as the elongated members 24 and 2:6 may be oriented between the
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wheel assembly 14 and the vehicle frame 12 so that they cross one another at
a -location either above or below the rotational axis R as seen in Fig. 1.
Moreover, in the embodiment of Fig. 1, the crossing axis C of the elongated
members 24 and 26 is approximately perpendicular to the rotational axis R. It
will be readily apparent that the rotational axis R and the crossing axis C
are
not required to be at any predetermined angle to one another in order for the
beneficial aspects of the present invention to bE~ realize,i. That is, the
rotational axis R and the crossing axis C need not necessarily be approxi-
mately perpendicular, but rather they may be apt any angle to one another,
1 0 such as but not limited to approximately 0°, 45" or 90°,
given a specific
configuration of the connection points on the ~;~heel assembly 14 and vehicle
frame 12.
The first and second elongated members, 24 and 26 respectively,
1 5 may be formed from any substantially rigid material including but not
limited to metal, a metal-alloy, a composite material or the like. Moreover,
each of the first and second elongated member;>, 24 and 26 respectively, need
not be a single unitary element, but rather rnay be formed from a plurality of
mated elements. Preferably, the spring and shock absorber assembly 20 is
2 0 attached to either the first elongated member 2.4 or the second elongated
member 26 via rotatable pin joint 36, while also being anchored to the
vehicle body 12 via rotatable pin joint 38, as shown in Fig. 1. As is further
illustrated in Fig. 1, the linking mechanism 22 is fixed to the kingpin 18 at
connection points 32 and 28 in any conventional manner so as to enable the
2 5 linking mechanism 22 to be freely rotatable about connection points 32 and
28 during operation of the suspension system 10. Vl~hile connection between
the shock absorber 20 and either of the elongated members 24 and 26,
respectively, has been described and shown in Fig. 1, the present invention is
not limited in this regard as the shock absorber 20 may alternatively be
3 0 connected to either the spindle 16 or the kingpin 18 without departing
from
the broader aspects of the present invention.
The connection points on the vehicle body 30 and 34,
respectively, may be Located as shown at in Fig;. 2 or at other points of the
3 5 vehicle frame 12 however, in order to provide for a zero roll suspension
system, it is preferable that the connection points 30 and 34 be fixed to the
vehicle frame 12 at points on the vehicle frame 12 which are approximately
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horizontally co-planar to the connection points 32 and 28, respectively. In
addition, it is preferable that the connection points 32 and 28 are to be
rotatably fixed to the spindle 16 or the kingpin '.E8 so as to be
approximately
vertically co-planar with one another, while the connection points 30 and 34
are to be rotatably fixed to the vehicle frame 12 so as to be approximately
vertically co-planar with one another as well. Moreover, each of the
connection points, 30, 34, 32 and 28 respectively, may be fixed to the vehicle
frame 12, and the spindle 16 or the kingpin 18, in any conventional manner,
such as but not limited to a pin joint or a ball joint, provided that the
linking
1 0 mechanism 22 is freely rotatable about the connection points 30, 34, 32
and
28 during operation of the suspension system 7Ø By changing the vertical
distances between the connection points 32 andL 28, as well as between the
connection points 30 and 34, the roll reducing effect may be correspondingly
increased or decreased, as will be discussed in greater detail in relation to
1 5 Fig. 4.
The first elongated member 24 must be long enough to reach
between a first connection point 28 which, as discussed previously, may be
fixed to the kingpin 18 or the spindle 1&, and a second connection point 30
2 0 on the vehicle body or frame 12 in a substantially passive manner, that
is,
such that the first elongated member 24 does not cause any active stressing
on the vehicle body 12, the spindle 1b, the kingpin 18 or the second elongated
member 26. Similarly, the second elongated member 26 must be long
enough to reach between a first connection point 32, which may be on the
2 5 kingpin 18 or the spindle 16, and a second connection point 34, which may
be
on the vehicle body 12, in a largely passive manner, that is, such that the
second elongated member 26 does not cause any active stressing on the
vehicle body 12, the spindle 16, the kingpin 18 or the first elongated member
24. While the kingpin 18 or the spindle 16 has been described as the preferred
3 0 anchoring location for the linking mechanism 22, the present invention is
not limited in this regard as other, alternative anchoring locations may be
substituted so long as the linking mechanism 2'.2 is fixedly attached, on one
side thereof, to a portion of the wheel assemble 14 which remains
substantially stationary with respect to a turning motion of the wheel itself.
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As utilized above with reference to the embodiment of Fig. 1,
and hereinafter in conjunction with alternativE> embodiments of the linking
mechanism according to the present invention, the terms 'cross', 'crosses',
'crossed' or 'crossing' represents the relative arrangement of the connection
points 28, 30, 32 and 34, or their equivalents in lFigs. 2-17, as viewed hori-
zontally. That is, if the connection point 28 of t:he elongated member 24 is
located vertically below the connection point 32 of the elongated member 26,
then the connection point 30 of the elongated member 24 must be oriented
vertically above the connection point 34 of the elongated member 26.
In operation, the suspension system 10 as illustrated in Fig. 1
acts to reverse the rolling load moment at the wheel of the vehicle and
transfers this reversed rolling load moment to the vehicle frame 22. The
rolling load moment is typically generated by t'.he force at the portion of
the
1 5 wheel contacting a travel surface during operation of the vehicle; such as
but
not limited to a cornering, acceleration or braking of the vehicle, or the
like.
Fig. 2 illustrates another embodiment of the zero roll suspen-
sion system of the present invention, generally designated by numeral 100.
2 0 While Fig. 1 depicts first and second single elongated members, 24 and 26
respectively, crossing in approximately parallel vertical planes, Fig. 2
illustrates the suspension system 100 wherein the linking mechanism 122
includes two, nested pairs of elongated members, 124/124' and 126/126',
respectively. The partial perspective view of F:ig. 2a more clearly
illustrates
2 5 the nested pairs of elongated members 124/129:' and 126/126' which
comprise
the linking mechanism 122 of the suspension system 100.
The two pairs of elongated members, 124 / 124' and T26/ 126'
respectively, physically intersect one another b~~ way of a pass-through
3 0 opening 137 defined between the outermost pair of elongated members
124/124'. It should be readily apparent that the pass-through 137 must be
fashioned so as to be somewhat larger in width than the width of the
elongated member pair which is situated within the pass-through 137. This
arrangement and size of the pass-through 137 allows for the compensating
3 5 movement of the pair of elongated members, l'~26 /126' respectively,
relative
to the outermost pair of elongated members 124/124'. In the embodiment
shown in Fig. 2, the crossing axis C of the two pairs of elongated members
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224/124' and 226/126' is approximately perpendicular to the rotational axis R,
however, as mentioned previously, this angular relationship is not critical to
the operation of the present invention and may be any angle, such as but not
limited to approximately 0°, 45° or 90°. it will lbe
readily apparent that the
two pairs of elongated members, 124/124' and 126/126' respectively, are
fashioned so as to minimize any frictional contact between one another,
wherein no contact at all is the preferred arrangement.
Fig. 3 illustrates a top, partial cross-sectional plan view of the
1 0 suspension system 100. As discussed above, the suspension system 100 is
such that the linking mechanism 122 includes two nested pairs of elongated
members, 124 / 124' and 126 / 126', respectively All four elongated members,
124, 124', 126 and 126', are shown as being fixed to the wheel assembly 114
and the vehicle body 112 in a manner similar to the discussion of the
1 5 suspension system 10 of Fig. 1. The first elongated members, 124 and 124'
respectively, are depicted as an outside link between the wheel assembly 214
and the vehicle frame 112, while the second pair of elongated members, 12G
and 126' respectively, are shown as an inside link between the wheel
assembly 214 and the vehicle frame 112 crossing the first pair of elongated
2 0 members, 124 and 124', in parallel vertical planes. This particular
arrange-
ment and number of stabilizing elongated members 124, 124', 226 and 226',
provides fox compensation of the rolling load moment of a cornering
vehicle, but with even greater stability and compensation capabilities than
the suspension system 10 of Fig. 1.
The orientation and interaction of forces with respect to the
embodiment illustrated in Fig. 1, and similar to the orientation and
interaction of forces as illustrated in further embodiments of the present
invention, are shown schematically in Figs. 4 and 5. Referring to Fig. 4, the
3 0 forces on a vehicle traveling forward (into the paper) and turning right
are
depicted. The lateral or radial acceleration on the frame of the vehicle 12
gives rise to force FAx which causes the vehicle to rotate or roll during
cornering. Friction between the wheel assembly 14 and the road creates a
cornering force shown as force vector WCx, t:he magnitude of which is
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determined by the weight and speed of the vehicle. For a four wheeled
vehicle with 1 /4 of the weight on each tire:
WCx = mass vehicle x lateral acceleration
4
Lateral forces that the elongated members, 24 and 26
respectively, apply to the connection points 32, 28, 30 and 34 are shown as
force vectors WAx, WBx, FCx and FDx respectively, where:
WBx = - FCx and
WAx = - FDx
Given distances d1 and d2, WBx can be calculated by summing
1 5 the moments of forces WCx and WBx about connection point 32:
~ M = 0 = (d1) WCx + (d2) WBx
Using the values thus determined for WCx and WBx, WAx can
2 0 be calculated by summing the force vectors in the x-direction:
~Fx=0=WCx-WBx+WAx
The roll canceling ability of the present invention can be
2 5 decreased by either increasing the distance d2, or by decreasing the
distance
(d4 + d~). Conversely, the roll canceling ability of the present invention can
be increased either by decreasing the distance d2, or increasing the distance
(d4 + d5). Accordingly, it is the vertical distances between the connection
points which primarily affect the roll canceling; ability of the present
3 0 invention, while any changes in the horizontal distances between the
connection points will primarily affect the cambering of the wheel during
operation of the vehicle.
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Referring to the free body diagram depicted in Fig. 5 and the
formula below, the body rolling moment MR is calculated about the projected
intersection of the elongated members 24, and 26 (unillustrated in Fig. 5)
which is midway between connection points 30 and 34.
~ MR = (d3) FAx - (d4) FCx -(d5) FDx
By selectively choosing the distance between connection points
30 and 34, the body roll moment can.be made to approach zero.
In the embodiments of the suspension systems 10 and 100, as
depicted in Figs. 1-3, the elongated members cross each other in parallel
vertical planes and connect the wheel assembly 14 to the vehicle frame 12. In
the suspension system 100 as depicted in Figs. 2-3, each of the two linking
1 5 mechanisms 122 has pairs of inside and outside elongated members, 124/124'
and 126/126'. respectively, rotatably fixed to the wheel assembly 114 and to
the
vehicle frame 112. As described previously, the outside links 124/124' are
attached to either the kingpin 118 or spindle 1116 at points 128 and to the
vehicle body 112 at points 130. The inside link, 126/126' are attached to
2 0 either the kingpin 118 or the spindle 116 at points.132, vertically above
or
below points 128, and to the vehicle body 112 ai: points 134, vertically above
or below points 130, such that the outside and inside links, 124/224' and
126/126' respectively, are arranged in a crossed pattern.
2 S Figs. ba and 6b illustrate a partial cross-sectional view of the
suspension system 10 of Fig. 1 being incorporated into a front wheel drive
vehicle 41. Fig. ba illustrates the front end of the front wheel drive vehicle
41, including a drive shaft 25 in relation to the linking mechanisms 22
affixed between each wheel assembly 14 and th.e vehicle frame 12. It should
3 0 be readily apparent that the drive shaft 25 does not interfere with the
application of the linking mechanisms 22 during the operation of the
suspension system 10 as described previously in conjunction with Fig. 1.
Fig. 6b illustrates the back end of the front wheel drive vehicle
3 5 41, including the linking mechanisms 22 affixed between each wheel
assembly 14 and the vehicle frame 12. While the linking mechanism 22,
including single elongated members 24 and 26, is shown as being affixed
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between each wheel assembly T4 and the vehicle frame 22 in the cross-
sectionai view of Figs. 6a and 6b, the present invention is not limited in
this
regard as pairs of linking mechanisms may be affixed at each wheel assembly
14 location, similar to the arrangement illustrated in Figs. 2-3, without
departing from the broader aspects of the present invention.
In a similar fashion to the application as shown in Figs. 6a and
6b, the linking mechanism 22 may be implemented at each wheel assembly
14 on a rear wheel drive vehicle 43, as depicted schematically in Figs. 7a and
1 0 7b. The linking mechanism 22 may also be implemented at each wheel
assembly 14 on a four-wheel drive vehicle 47 as shown in Figs. Sa and 8b, or
on a vehicle 51 having in hub motors as shown in Figs. 9a and 9b. While the
linking mechanism 22, including single elongated members 24 and 26, is
shown as being affixed between each wheel assembly 14 and the vehicle
1 5 frame 12 in the cross-sectional views of Figs. 7a, 7b, 8a, 8b, 9a and 9b,
the
present invention is not limited in this regard .as pairs of linking
mechanisms may be affixed at each wheel assembly 14 location, similar
to the arrangement illustrated in Figs. 2-3, without departing from the
broader aspects of the present invention.
An additional aspect of the present invention is the application
of a zero roll suspension system to only some of the wheel assembly
locations of a given vehicle, such as to the front or rear wheels only, while
the other wheel assembly locations are equipped with alternative suspension
2 5 systems, such as struts. When applied in this manner, although roll
cancellation may not be balanced, substantial compensation of the vehicle
roll encountered during cornering, acceleration and braking may still be
obtained.
3 0 Fig. 10 illustrates a partial cross-sectional view of yet another
embodiment of the suspension system of the present invention, generally
designated by reference numeral 200. The suspension system 200 utilizes a
drive shaft 225 to act as either one the two elongated members in linking
mechanism 222. The drive shaft 225 passes through the center of the spindle
3 5 216 and is attached thereto in a conventional r~ianner. The drive shaft
225 is
also connected to a fixed portion of a largely unillustrated drive train 244
in a
conventional manner. The draft shaft 225 provides structural support
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between the wheel assembly 214 and the vehicle body 212 and is substantially
co-axial with the rotational axis R of the wheel assembly 214. A shock
absorber 220 provides vertical support for the v~~heel assembly 214 and the
vehicle frame 212. Preferably, the shock absorber 220 is fixedly attached to a
single elongated member 224 via rotatable pin joint 236. It will be readily
appreciated that the shock absorber 220 may be of any type, such as but not
limited to a spring shock absorber, a gas shock absorber or a hydraulic shock
absorber, and further, that the shock absorber 2:>_0 may be fixed by the
rotatable
pin joint 236 to any point along the single elongated member 224, or to any
1 0 conventional location on the wheel assembly 214, including the spindle 216
and the kingpin 218, in dependence upon the particular suspension design of
a specific vehicle, without departing from the broader aspects of the present
invention.
I 5 Referring still to Fig. 10, the single elongated member 224 is
rotatably fixed to the kingpin 218 at a connection point 228 and to the
vehicle
body 212 at a connection point 230. The vertical orientation of these
connection points, 228 and 230 respectively, are functionally interchangeable
in that either may be located higher than the other with respect to the plane
2 0 of the driving surface 203, provided that the connection points, 228 and
230
respectively, are positioned such that the single elongated member 224 and
the drive shaft 225 are inclined with respect to one another so as to cross in
substantially parallel vertical planes along a crossing axis C.
2 5 Fig. 11 illustrates a top, partial crass-sectional view yet another
embodiment of a suspension system according to the present invention,
generally designated by the reference numeral 200'. The suspension system
200' is similar to the suspension system 200, illustrated in Fig. 10, in its
utilization of the drive shaft 225 as a support member. The suspension
3 0 system 200', however, utilizes a pair of two similarly inclined elongated
members, 224 and 224' respectively, situated an either planar side of the
drive shaft 225, as shown in Fig. 11, where the drive shaft 225 is shown as
the
inside link of the linking mechanism 222'. Th.e present embodiment,
therefore, contemplates including the pair of elongated members, 224 and
3 5 224' respectively, in a manner similar to the utilization of the two pairs
of
elongated members as shown and described in conjunction with Figs. 2-3.
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In accordance with the previous embodiments of the present invention, the
elongated members, 224 and 224' respectively, a:re rotatably fixed between the
vehicle frame 222 and either the spindle 216 or the kingpin 218 on the wheel
assembly 214.
As shown in Figs. 12a and 12b, , the linking mechanisms, 22 and
222 respectively, are implemented on each of th.e four wheel assemblies 214
of a vehicle 241. Vehicle 241 may be either a front wheel drive vehicle or a
rear wheel drive vehicle wherein Fig. 12a illustrates those wheel assemblies
1 0 214 which are not actively driven in the front or rear wheel drive vehicle
241, and Fig. 12b illustrates those wheel assemblies 214 which utilize a drive
shaft 225 and are actively driven in the front or rear wheel drive vehicle
241.
In the suspension system integrated into the wheel assemblies 214 shown in
Fig. 12b, the drive shaft 225 serves as one of the elongated members crossing
1 5 elongated member 224 to form the crossed linking mechanisms, 222 or 222'
respectively, illustrated in Figs. i0 or 11. Moreover, Fig. 12a illustrates
those
wheel assemblies 214 which do not utilize a drive shaft 225, but rather
utilize
the linking mechanisms, 22 or 122 respectively, affixed between each wheel
assembly 214 and the vehicle frame 212 in arrangements as previously
2 0 described in relation to Figs. 1-3.
More specifically, Fig. 12b illustrafies one end of the vehicle 241
including the linking mechanisms 222 or 222', shown in Figs. 10 and 11,
affixed between each wheel assembly 214 and the vehicle frame 212, wherein
2 5 the drive shaft 225 provides structural support between the wheel assembly
214 and the vehicle body 212. It should be readily apparent that the drive
shaft 225 does not interfere with the application of the linking mechanisms
222 or 222' during the operation of the suspensiion system 200 or 200'.
3 0 The embodiments of the present invention as illustrated in
Figs. 1-12b have shown various specific arrangements a zero roll suspension
system, as well as disclosing how various specific designs of such a zero roll
suspension system may be combined to accommodate differing vehicle types
and desired ride characteristics. As is evident in the embodiments shown in
3 5 Figs. 1-12b, the linking mechanism between the wheel assembly and the
vehicle frame have been shown for illustration purposes as having a
crossing axis C -which is oriented approximately perpendicular to the
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rotational axis R of the wheel assembly. In the alternative, Fig. 13
illustrates
yet another embodiment of a zero roll suspension system, designated by the
reference numeral 300, wherein the linking mechanism between the wheel
assembly and the vehicle frame has a crossing axis C which is oriented
approximately parallel to the rotational axis R of the wheel assembly 314. It
will be readily apparent that the rotational axis R and the crossing axis C
are
not required to be at any predetermined angle to one another in order for the
beneficial aspects of the present invention to be realized. That is, the
rotational axis R and the crossing axis C need not necessarily be
1 0 approximately parallel, but rather may be at an,y angle to one another,
such as
but not limited to approximately 0°, 45° or 90°, given a
specific configuration
of the connection points on the wheel assembly 314 and vehicle frame 312.
More specifically, the suspension system 300 is adapted to be
1 5 received by the body of a vehicle, such as an automobile frame 312, having
a
wheel assembly 314, a spindle 316, a kingpin 318, and a spring and shock
absorber assembly 320. The wheel assembly 314 has an axis of rotation R
about which a wheel of the wheel assembly 314 rotates. The vehicle frame
312 may be of any automobile make or model, .a pick-up truck, an utility
2 0 truck, a three-wheeled, a four-wheeled or more wheeled vehicle that tends
to
rotate or roll, during cornering.
The spring and shock absorber assembly 320 provides vertical
support for the wheel assembly 324 and the vehicle frame 312 while, as is
2 5 commonly known, the wheel assembly 314, the spindle 316 and the kingpin
318 are each integrally connected in a conventional manner so as to provide
for structural stability and control of the vehicle. While the suspension
system 300 will function with most vehicles, it should be readily apparent
that the actual size of various components will depend upon the size and
3 0 weight of the associated vehicle. It should be readily apparent that while
one
linking mechanism 322 has been described, more than one linking
mechanism may be alternatively substituted without departing from the
broader aspects of the present invention, as will be described later.
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Referring still to Fig. 13, the linking mechanism 322 of the
present invention reverses the moment, preferably at the wheel, to oppose
the rolling moment of the vehicle body 312 during cornering. The linking
mechanism 322 includes at least a first elongated member 324 and a second
elongated member 326 which are oriented so as to cross each other in parallel
planes along a crossing axis C. Each elongated member, 324 and 326
respectively, are additionally oriented so as to cross the rotational axis R
of
the wheel assembly 314. The present invention, however, is not limited in
this regard as the elongated members 324 and 326 may be oriented between
1 0 the wheel assembly 314 and the vehicle frame 312 so that they cross one
another at a location either above or below the rotational axis R as seen in
Fig. 13. Moreover, in the embodiment of Fig. 1~~, the crossing axis C of the
elongated members 324 and 326 is approximately parallel to the rotational
axis R. It will be readily apparent that the rotational axis 1Z and the
crossing
i 5 axis C are not required to be at any predetermined angle to one anather in
order for the beneficial aspects of the present invention to be realized. As
noted above, the rotational axis R and the crossiing axis C need not
necessarily be approximately parallel, but rather they may be at any angle to
one another given a specific configuration of the connection points on the
2 0 wheel assembly 314 and vehicle frame 312.
The first and second elongated members 324 and 32b may be
formed from a metal, a metal-alloy or the like, provided they remain
substantially rigid. Preferably, the spring and srEOCk absorber assembly 320
2 5 is attached to either the first elongated member 324 or the second
elongated
member 326 via rotatable pin joint 336, while alLso being anchored to the
vehicle body 312 via rotatable pin joint 338. As is further illustrated in
Fig.
13, the linking mechanism 322 is fixed to the kingpin 318 at connection
points 332 and 328 in any conventional manner so as to enable the linking
3 0 mechanism 322 to be freely rotatable about connection points 332 and 328
during operation of the suspension system 300. While connection between
the shock absorber 320 and either of the elongated members, 324 and 326
respectively, has been described and shown in :Eig. 13, the present invention
is not limited in this regard as the shock absorber 320 may alternatively be
3 5 rotatably fixed to either the spindle 316 or the kingpin 318 without
departing
from the broader aspects of the present invention.
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The connection points on the vehicle body 330 and 334,
respectively, may be located as shown at in Fig. 13 or at other points of the
vehicle frame 312, however, it is preferable that the connection points 330
and 334 be fixed to the vehicle frame 312 at points on the vehicle frame 322
S which are approximately horizontally co-planar to the connection points 332
and 328, respectively. In addition, it is preferable that the connection
points
332 and 328 are to be rotatably fixed to either the spindle 316 or the kingpin
318 so as to be approximately vertically co-planar with one another, while it
is preferable that the connection points 330 and 334 are to be rotatably fixed
to
1 0 the vehicle frame 322 so as to be approximately vertically co-planar with
one
another as well. Moreover, each of the connection points, 330, 334, 332 and
328 respectively, may be fixed to the wheel assembly 314, including either
the spindle 316 or the kingpin 318, and to the vE~hicle frame 322 in any
conventional mariner, such as but not limited to a pin joint or a ball joint,
1 S provided that the linking mechanism 322 is freely rotatable about the
connection points 330, 334, 332 and 328 during operation of the suspension
system 300. It will be readily apparent that by changing the vertical
distances
between the connection points 332 and 328, as v~~ell as between the connection
points 330 and 334, the roll reducing effect may l'oe correspondingly
increased
2 0 or decreased.
The first elongated member 324 must be long enough to reach
between a first connection point 328 which, as discussed previously, may be
fixed to the kingpin 328 or the spindle 316, and a second connection point 330
2 S on the vehicle body or frame 312 in a substantially passive manner, that
is,
such that the first elongated member 324 does not cause any active stressing
on the vehicle body 312, the spindle 316, the kingpin 318 or the second
elongated member 326. Similarly, the second elongated member 326 must be
Iong enough to reach between a first connection point 332, which may be on
3 0 the kingpin 318 or the spindle 316, and a second connection point 334,
which
may be on the vehicle body 312, in a largely pas:>ive manner, that is, such
that
the second elongated member 326 does not cause any active stressing on the
vehicle body 312, the spindle 316, the kingpin 318 or the first elongated
member 324. While the kingpin 318 or the spindle 316 has been described as
3 S the preferred anchoring location for the linking mechanism 322, the
present
invention is not limited in this regard as other, alternative anchoring
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locations may be substituted so long as the linking mechanism 322 are fixedly
attached to a portion of the wheel assembly 314 which remains substantially
stationary with respect to a turning motion of t:he wheel itself.
In operation, the suspension system 300 as illustrated in Fig. I3
acts to reverse the rolling load moment at the wheel of the vehicle and
transfers this reversed rolling Load moment to the vehicle frame 312. The
rolling load moment is typically generated by the force at the portion of the
wheel contacting a travel surface during operation of the vehicle, such as but
1 0 not limited to a cornering, acceleration or braking of the vehicle, or the
like.
Fig. 14 illustrates a partial cross-sectional plan view of the
suspension system 300 of Fig. 13 being incorporated into a vehicle 341, such
as but not limited to a front wheel drive vehicle, a rear wheel drive vehicle
1 5 or a four wheel drive vehicle. Fig. 14 illustrates the linking mechanisms
322
affixed between each wheel assembly 314 and the vehicle frame 312 in a
manner as discussed above in conjunction with. Fig. I3. While only a single
linking mechanism 322 is shown as being affixed between each wheel
assembly 314 and the vehicle frame 312 in the cross-sectional plan view of
2 0 Fig. 14, the present invention is not limited in this regard as pairs of
linking
mechanisms may be affixed at each wheel assembly 314 location, similar to
the arrangement illustrated in Figs: 2-3, without departing from the broader
aspects of the present invention.
2 5 As discussed above, Figs. 1-1g of the present invention are
concerned with a plurality of specifically oriented elongated members,
preferably formed from any substantially rigid material including but not
limited to metal, a metal-alloy, a composite material or the like. Moreover,
as was also discussed, each of the elongated members need not be a single
3 0 unitary element, but rather may be formed frorn a plurality of mated
elements. Figs. 15 and 16 illustrate two specific' examples of alternative
design embodiments of the elongated members capable of being utilized in
each of the foregoing configurations as depicted in Figs. 1-14.
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Fig. 15 illustrates a zero roll suspension system 400 adapted to be
received by the body of a vehicle, such as an automobile frame 412, having a
wheel assembly 414, a spindle 416 and a kingpin 418. A crossed linking
mechanism 422 acts to connect the wheel assembly 414 to the vehicle body
412 . It should be readily apparent that while one linking mechanism 422
has been described, more than one linking mechanism may be alternatively
substituted without departing from the broader aspects of the present
invention, as has been described in conjunctior,~ with the embodiments of
Figs. 1-14.
Referring still to Fig. 15, the linking mechanism 422 of the
present invention reverses the moment, preferably at the wheel, to oppose
the rolling moment of the vehicle body 412 during cornering. The linking
mechanism 422 includes a first elongated member 424 which crosses a second
1 5 elongated member 426 and performs shock and. springing functions in
addition to the zero roll attributes discussed previously. The first and
second
elongated members of this type, 424 and 426 respectively, are preferably
formed as flexible members, such as but not limited to multi-layered
composite, elongated members having alternating layers of composite fibers
2 0 and energy dampening elastomeric materials. While Fig. 15 depicts the
matched connection points 432 and 428 as being rotatably fixed to the kingpin
418 and the matched connection points 430 and 434 as being non-rotatably
fixed to the vehicle frame 412, the present invention is not limited in this
regard. The matched connection points 430 and 434 may alternatively be
2 5 rotatably fixed to the vehicle frame 412 so long as the matched connection
points 432 and 428 are non-rotatably fixed to either the spindle 41b or the
kingpin 418.
Fig. 16 illustrates a zero roll suspension system 500 according to
3 0 another embodiment of the present invention. The zero roll suspension
system 500 is adapted to be received by the body of a vehicle, such as an
automobile frame 512, having a wheel assembly 514, a spindle 516, a kingpin
518 and a spring and shock assembly 520. A crossed linking mechanism 522
acts to connect the wheel assembly 514 to the vehicle body 512 . It should be
3 5 readily apparent that while one linking mechanism 522 has been described,
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more than one linking mechanism may be alternatively substituted without
departing from the broader aspects of the present invention, as has been
described in conjunction with the embodiments of Figs. 1-14.
Referring still to Fig. 16, the linking mechanism 522 of the
present invention reverses the moment, preferalbly at the wheel, to oppose
the rolling moment of the vehicle body 512 during cornering. The linking
mechanism 522 includes a first elongated member 524 which crosses a second
elongated member 526 and performs the zero roll attributes discussed
1 0 previously. The first and second elongated members of this type, 524 and
526
respectively, are preferably formed as variable length elongated members,
such as but not limited to hydraulic or pneumatic cylinders. While Fig. 16
depicts both of the elongated members, 524 and 526 respectively, as being
variable length members the present invention is not limited in this regard
1 5 as only one of the elongated members, 524 and Gi26 respectively, may alter-
natively be a variable length member without departing from the broader
aspects of the present invention. The connection points 532, 528, 530 and 534
of the elongated members 524 and 526 are configured to be rotatably fixed
between the vehicle frame 512 and either the spindle 516 or the kingpin 518
2 0 in any conventional manner, such as but riot limited to a pin joint or a
ball
joint, provided that the linking mechanism 522 is freely rotatable about the
connection points 532, 528, 530 and 534 during operation of the suspension
system 500.
2 5 The suspension system 500 advani;ageously optimizes tire
camber, grip and other road handling characteristics of a vehicle when one or
both of the elongated members 524 and 526 are selectively lengthened during
cornering, braking or accelerating. This may be achieved by elongating one of
the elongated members 524 and 526 when the spring and shock assembly 520
3 0 is compressed.
In view of the foregoing, the present invention contemplates a
zero roll suspension system that reduces cornering roll, acceleration squat
and braking dive to nearly zero through the use of crossed mechanical
3 5 linkages that cancel the rolling moments at each wheel location.
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Fig. 17 illustrates a top, partial crass-sectional view yet another
embodiment of a suspension system according to the present invention,
generally designated by the reference numeral 600. The suspension system
600 is similar to the suspension systems illustrai:ed in Figs. 1-16, however
the
suspension system 600 additionally includes a toe control bar 650 which
assists in maintaining the wheel assembly 614 in a proper drive orientation.
A linking mechanism 622 includes a pair of crossing members, 624 and 626
respectively, in close association with a drive shaft 625. The crossing
members 624 and 626 are rotatably fixed between the vehicle frame 612
i 0 and either the spindle 616 or the kingpin 618 on the wheel assembly 614
so as to cross one another in superposition The toe control bar 650 is like-
wise fixed between the vehicle frame 612 and either the spindle 61b or the
kingpin 628 on the wheel assembly 614 in any conventional manner,
such as but not limited to a ball joint, so as to allow for a wide range of
I 5 movement of the toe control bar 650. The toe control bar 650 is preferably
oriented so as to be aligned with either one of the crossing members; 624
and 626 respectively, thereby providing the greatest amount of control over
the wheel assembly 614.
2 0 While the suspension system 600 as depicted in Fig. 17 has been
described as including a crossed pair of crossing members, 624 and 626
respectively, which are rotatably fixed between the wheel assembly 614 and
the vehicle frame 612, the present invention is :not limited in this regard.
The crossing members 624 and 626 may be alternatively fixed between the
2 5 wheel assembly 614 and the vehicle frame 612 i:n a manner as described in
conjunction with Figs. 15 and 16, depending upon the particular structural
nature of the crossing members 624 and 626. Moreover, the arrangement of
the crossing members 624 and 626 with respect to the drive shaft 625 and the
toe control bar 650 may also be altered from the position indicated in Fig.
17,
3 0 provided that the crossing members 624 and 626 cross one another in
superposition and the tae control bar 650, when viewed horizontally, is
substantially aligned with one of crossing members 624 and 626. A pair of
elongated members may alternatively be substituted for each of the crossing
members 624 and 626, as has been discussed in conjunction with the
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previously disclosed embodiments of the present invention. The suspension
system 600 of Fig. 17 is primarily concerned with the role and orientation of
the toe control bar 650 and may be implemented in conjunction with the
wheel assemblies of Figs. 1-16 with or without the drive shaft 625.
It will be readily apparent to one o~f ordinary skill in the art that
attributes of the embodiments as depicted in Fi~;s. 1-17 may be interchanged
with one another without departing from the broader aspects of the present
invention.
As discussed previously, a major aspect of the present invention
is that the location of the connections points for the linking mechanism may
be varied, provided that the elongated members of the linking mechanism
remain crossed, so as to allow a desired amount of vehicle frame roll. Slight
1 5 adjustments in the specific location of these connection points provide
for
the cambering by the wheels into a corner to thereby improve the cornering
grip of a vehicle so equipped. Moreover, although the elongated members of
the linking mechanism, including the various embodiments thereof, may
cross one another in parallel planes as viewed horizontally , the present
2 0 invention is not limited in this regard as the elongated members may have
any planar relationship between one another provided that when viewed
horizontally, the elongated members cross in superposition.
Another major aspect of the present invention is that the
2 5 rotational axis of the wheel assembly and the crossing axis of the linking
mechanism are not required to be at any predetermined angle to one another
in order for the beneficial aspects of the present invention to be realized.
That is, the rotational axis and the crossing axis need not necessarily be
either
approximately perpendicular or approximately parallel, but rather they may
3 0 be at any angle to one another given a specific configuration of the
connection points on the wheel assembly and vehicle frame.
Although the present invention h.as been illustrated and
described with reference to preferred embodiments, it will be appreciated by
3 5 those of ordinary skill in the art, that various modifications to this
invention
may be made without departing from the spirit and scope of the invention.
