Note: Descriptions are shown in the official language in which they were submitted.
CA 02247776 1998-09-25
STABILITY MAINTAINING SHOCK ABSORBING
BICYCLE FRONT FORK AND TRAILING ARM ASSEMBLY
FIELD OF THE INVENTION:
This invention relates to bicycle suspension systems and more particularly
to shock absorbing bicycle front fork and trailing arm assemblies for mounting
a
front wheel on a otherwise conventional bicycle.
BRIEF DESCRIPTION OF THE DRAWINGS~
The novel features which are believed to be characteristic of the present
invention, as to its structure, organization, use and method of operation,
together
with further objectives and advantages thereof, will be better understood from
the
following drawings in which a presently preferred embodiment of the invention
will
now be illustrated by way of example. It is expressly understood, however,
that the
drawings are for the purpose of illustration and description only and are not
intended as a definition of the limits of the invention. Embodiments of this
invention will now be described by way of example in association with the
accompanying drawings in which:
Figure 1 is a simplified pictorial representation of a conventional front
forks
with a bicycle wheel mounted thereon, and showing various geometrical
measurements;
Figure 2 is a simplified pictorial representation of a front portion of a
conventional bicycle frame and front forks, with a bicycle wheel mounted
thereon,
and showing the geometry involved therewith during turning of the front forks
and
wheel;
Figure 3 is a graph of the relative front projection versus the head angle of
various bicycles;
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CA 02247776 1998-09-25
Figure 4A is a side elevational view of a first preferred embodiment of the
stability maintaining shock absorbing bicycle front fork and trailing arm
assembly
of the present invention, in a normally extended configuration;
Figure 4B is a side elevational view similar to Figure SA, with the front fork
and trailing arm assembly in a compressed configuration;
Figure SA is a side elevational view of a second preferred embodiment of
the stability maintaining shock absorbing bicycle front fork and trailing arm
assembly of the present invention, in a normally extended configuration;
Figure SB is a side elevational view similar to Figure 6A, with the front fork
and trailing arm assembly in a compressed configuration; and
Figure 6 is a graph comparing the stability curves of both a conventional
telescopic front fork assembly and the front fork and trailing arm assembly of
the
present invention.
BACKGROUND OF THE INVENTION:
Bicycles have been known in the world for well over one hundred years.
The basic form and resulting function of bicycles were established very early
in the
development of the bicycle - that is to say that even most very early bicycles
comprised a frame, a non-steerable rear wheel powered by a crank arm type
pedal
linked to the rear wheel through a chain and sprocket assembly, and a
steerable
front wheel assembly including a front wheel rotatably mounted on a pair of
left and
right front forks. The front forks are joined together at a hub connected to
the
steering spindle. The steering spindle is pivotally mounted in a front frame
portion
for pivotal movement about a steering axis. The steerable front wheel assembly
is
controllable by means of a manually manipulable hand grip. This fundamental
form
and function is still found in virtually all conventional bicycles.
One feature that was included even on very early conventional bicycles is
that of forward curvature of the front forks, which forward curvature causes
the
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CA 02247776 1998-09-25
front forks to extend forwardly at their bottom ends to terminate at a point
ahead
of the steering axis of the bicycle. The reason for such forward extension of
the
front forks is to provide a front fork offset, as can be seen in Figure 1. The
front
fork offset y is defined as the perpendicular distance between the steering
axis and
the axis of rotation of the front wheel. The purpose of the front fork offset
is to
provide stability to the steering of a bicycle. The stability of the bicycle
is, in
essence, the measure of the tendency of the bicycle to remain controllable,
and
therefore rideable, during steering manoeuvres. It is generally accepted that
stability
may be expressed by the following relation:
w a2 [fl d]
aaaz, )a=o
wherein f is the frame height, d is the diameter of the front wheel (thereby
making
fld the relative frame height), a is the steering angle - or, in other words,
the angle
between the plane of the frame of the bicycle and the plane of the front wheel
- ,
and L is the lean angle - or, in other words, the angle between the plane of
the
frame and a vertical plane. Empirical evidence indicates that using this
relation,
bicycles tend to have good steering characteristics when ~, is between -1 and -
3. It
can be seen in Figure 2, that the lean angle L is affected by the front fork
offset.
Therefore, the stability is affected by the front fork offset.
The concept of stability of a bicycle can perhaps be more readily understood
as expressed graphically in Figure 3, which relates the stability value ~ to
the
relative front projection of the axis of rotation of the front wheel as
compared to the
steering axis and the head angle. The stability value ~, is indicated for a
variety of
bicycles. The relative front projection of the axis of rotation of the front
wheel is
defined as the horizontal distance between the axis of rotation of the front
wheel
and the point at which the steering axis intersects a horizontal line passing
therethrough, divided by the diameter of the front wheel, as can be seen in
Figure
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CA 02247776 1998-09-25
4. As can be seen from Figure 3, most bicycles have a relative front
projection x
in the order of +0.1 and a stability value w between about -1 and -3. As can
be
discerned through Figures 1 and 4, the relative front projection is related to
the front
fork offset y and the head angle H, with the head angle is the angle between
the
ground and the steering axis. The head angle H and the relative front
projection x
therefore also affect the stability of a bicycle, since they are related to
the front fork
offset.
It would therefore seem reasonable that, in order to provide an extremely
safe bicycle, it would merely be a matter of increasing the stability of a
bicycle such
that the stability value ~, is between about perhaps -5 and -10. Such increase
in
stability could be accomplished simply by decreasing the front fork offset,
and
therefore the relative front projection, and/or decreasing the head angle;
however,
it has been found that it is necessary to have a relative front projection in
the order
of 0.05 to 0.10 and a head angle from about 72° to about 75° in
order to provide
suitable handling characteristics for a bicycle. In other words, in order to
have
reasonable stability and acceptable handling characteristics, the relative
front
projection and the head angle must fall within a certain range. Any variation
of the
front relative projection or head angle outside the above stated values will
compromise either the stability or the handling characteristics of a bicycle.
Most
conventional bicycles are fixed in terms of their head angle, relative front
projection,
and so on. Accordingly, their handling characteristics and stability are
predetermined. Some bicycles, however, such as more elaborate mountain
bicycles,
have shock absorbing front fork assemblies wherein the effective length of the
front
fork assembly necessarily changes. For instance, when the front wheel of a
bicycle
having a shock absorbing front fork assembly is raised off the ground and
subsequently impacts back on the ground, the front portion of the frame
continues
to move downwardly with respect to the front wheel for a few centimetres.
Accordingly, the effective height of the frame decreases temporarily.
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CA 02247776 1998-09-25
As can be seen from Figures 4A and 4B, or from Figures SA and SB, when
the frame height of a bicycle is decreased, that the head angle also
increases. As
can be seen in Figure 3, as indicated by arrow A, when the head angle is
increased,
the stability is decreased. It has been found that, in mountain bicycles
having a
front fork assembly with about five to seven and one half centimetres (two to
three
inches) of travel, the maximum change of head angle affects the stability of
the
bicycle only a minor amount; however, in mountain bicycles having a front fork
assembly with about fifteen centimetres (six inches) of travel, the maximum
change
in head angle significantly affects the stability of the bicycle. Such
significant
decrease in stability is potentially dangerous and must be compensated for. In
order
to maintain stability during full travel of a fork assembly with about fifteen
centimetres (six inches) of travel, it is possible to counteract the increase
in head
angle by correspondingly decreasing the relative front projection - or in
other words
the front fork offset - of the axis of rotation of the front wheel.
It is therefore an object of the present invention to provide a stability
maintaining shock absorbing bicycle front fork and trailing arm assembly for
mounting a front wheel on a conventional bicycle, which bicycle front fork and
trailing arm assembly is configured to such that the front fork offset
correspondingly
decreases with a decrease in the relative frame height of the bicycle due to a
corresponding compression of the front forks of the bicycle, thereby
maintaining
stable steering stable steering of the bicycle at all times.
It is therefore an object of the present invention to provide a stability
maintaining shock absorbing bicycle front fork and trailing arm assembly for
mounting a front wheel on a conventional bicycle, which bicycle front fork and
trailing arm assembly maintains stable steering stable steering of the bicycle
at all
times, even for compression of the front fork assembly of about fifteen
centimetres
(six inches), or even greater.
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CA 02247776 1998-09-25
DESCRIPTION OF THE PRIOR ART:
The following prior art references are known to the inventor:
~ United States Patent No. 3,954,284
~ United States Patent No. 5,413,368
~ United States Patent No. 5,427,208
~ United States Patent No. 5,429,380
~ United States Patent No. 5,431,426
~ United States Patent No. 5,445,401
~ United States Patent No. 5,449,155
~ United States Patent No. 5,456,480
~ United States Patent No. 5,462,302
These prior art patents disclose various kinds of suspension systems, fork
assemblies, and the like. It is not known in the prior art to accommodate a
compression of about fifteen centimetres (six inches) of a fork assembly while
compensating for the change in stability that follows such compression of the
front
forks in prior art devices.
SUMMARY OF THE INVENTION:
In accordance with one aspect of the present invention, there is provided a
stability maintaining shock absorbing bicycle front fork and trailing arm
assembly
for mounting a front bicycle wheel on a conventional bicycle for rotation of
the
front bicycle wheel about a displaceable axis of rotation, wherein the bicycle
has a
steering spindle pivotally mounted in a front frame portion thereof for
pivotal
movement of the steering spindle about a steering axis. The variable length
shock
absorbing bicycle fork assembly comprises a hub member rigidly attached to the
steering spindle for pivotal movement therewith. Opposed left and right fork
members each having a top end and a bottom end, are rigidly attached adjacent
their
top ends to the hub member so as to depend therefrom. Left and right trailing
arms
are operatively mounted one on each of the left and right fork members,
respectively, for pivotal movement of each trailing arm about a common pivot
axis
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CA 02247776 1998-09-25
oriented generally parallel to the displaceable axis of rotation of the front
bicycle
wheel and generally perpendicular to the steering axis and disposed forwardly
of the
steering axis. Bicycle wheel mounting means are disposed one on each of the
left
and right trailing arms so as to permit mounting of a front bicycle wheel
thereon
such that the front bicycle wheel rotates about the displaceable axis of
rotation.
When the front bicycle wheel is mounted on the bicycle wheel mounting means on
the left and right trailing arms, the left and right trailing arms are
concurrently
pivotally movable between a forward position whereat the displaceable axis of
rotation of the front bicycle wheel mounted on the front fork and trailing arm
assembly is disposed forwardly of the steering axis and between the steering
axis
and the common pivot axis, and a trailing position whereat the displaceable
axis of
rotation of the front bicycle wheel mounted on the front fork and trailing arm
assembly is disposed closer to the steering axis than when in the forward
position
and is also displaced vertically closer to the common pivot axis than when in
the
forward position. Variable length shock absorbing means comprises an upper
component and a lower component. The upper and lower components are slidably
engaged one with the other for relative movement between an extended
configuration and a compressed configuration, with the upper component
securely
mounted on the hub member. A linkage arm having a top end and a bottom end,
is pivotally mounted at its bottom end to a selected one of the left and right
trailing
arms for pivotal movement about a linkage arm lower axis, and pivotally
mounted
at its top end to the lower component of the shock absorbing means for pivotal
movement about a linkage arm upper axis, with the linkage arm upper and lower
axes being substantially parallel to the displaceable axis of rotation. A
spring
biasing means is operatively mounted between the hub member and the selected
trailing arm having the linkage arm mounted thereon, so as to bias the shock
absorbing means to the extended configuration and to bias the left and right
trailing
arms to their respective forward positions.
CA 02247776 1998-09-25
In accordance with another aspect of the present invention, there is provided
a stability maintaining shock absorbing bicycle front fork and trailing arm
assembly
for mounting a front bicycle wheel on a conventional bicycle for rotation of
the
front bicycle wheel about a displaceable axis of rotation, wherein the bicycle
has a
steering spindle pivotally mounted in a front frame portion thereof for
pivotal
movement of the steering spindle about a steering axis. The variable length
shock
absorbing bicycle fork assembly comprises a hub member rigidly attached to the
steering spindle for pivotal movement therewith. Opposed left and right fork
members each having a top end and a bottom end, are rigidly attached adjacent
their
top ends to the hub member so as to depend therefrom. Left and right trailing
arms
are operatively mounted one on each of the left and right fork members,
respectively, for pivotal movement of each trailing arm about a common pivot
axis
oriented generally parallel to the displaceable axis of rotation of the front
bicycle
wheel and generally perpendicular to the steering axis and disposed forwardly
of the
1 S steering axis. Bicycle wheel mounting means are disposed one on each of
the left
and right trailing arms so as to permit mounting of a front bicycle wheel
thereon
such that the front bicycle wheel rotates about the displaceable axis of
rotation.
When the front bicycle wheel is mounted on the bicycle wheel mounting means on
the left and right trailing arms, the left and right trailing arms are
concurrently
pivotally movable between a forward position whereat the displaceable axis of
rotation of the front bicycle wheel mounted on the front fork and trailing arm
assembly is disposed forwardly of the steering axis and between the steering
axis
and the common pivot axis, and a trailing position whereat the displaceable
axis of
rotation of the front bicycle wheel mounted on the front fork and trailing arm
assembly is disposed closer to the steering axis than when in the forward
position
and is also displaced vertically closer to the common pivot axis than when in
the
forward position. A variable length shock absorbing linkage arm comprises an
upper component having a top end and a bottom end, and a lower component
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CA 02247776 1998-09-25
having a top end and a bottom end. The upper and lower components are slidably
engaged one with the other for relative movement between an extended
configuration and a compressed configuration, with the upper component
pivotally
mounted at its top end on the hub member for pivotal movement about a linkage
arm upper axis, and with the lower component being pivotally mounted at its
bottom end to a selected one of the left and right trailing arms for pivotal
movement
about a linkage arm lower axis, with the linkage arm upper and lower axes
being
substantially parallel to the displaceable axis of rotation. A spring biasing
means
is operatively mounted between the hub member and the selected trailing arm
having the linkage arm mounted thereon, so as to bias the shock absorbing
means
to the extended configuration and to bias the left and right trailing arms to
their
respective forward positions.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
Reference will now be made to Figures 3 through 6, in which first and
second preferred embodiments of the stability maintaining shock absorbing
bicycle
front fork and trailing arm assembly of the present invention, are discussed.
Reference is first made to Figures 4A and 4B, where a first preferred
embodiment of the stability maintaining shock absorbing bicycle front fork and
trailing arm assembly 20 is shown. The front fork and trailing arm assembly 20
is
for mounting a front bicycle wheel 22 on a conventional bicycle 24. The front
wheel 22 rotates about a displaceable axis of rotation R. The bicycle 24 has a
steering spindle 26 pivotally mounted in a front frame portion 28 thereof, for
pivotal
movement of the steering spindle 26 about a steering axis S.
The variable length shock absorbing bicycle front fork assembly 20
comprises a hub member 30 rigidly attached to the steering spindle 26, such as
by
means of welding, or other suitable means, for concurrent pivotal movement of
the
hub member 30 with the steering spindle 26. Opposed left and right fork
members
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40 each having a top end 42 and a bottom end 44, and being rigidly attached
adjacent their top ends 42 to the hub member 30 so as to depend therefrom, are
each rigidly attached to the hub member 30, by means of welding. Alternatively
they may be integrally formed one with the other, or by any other suitable
conventional fastening means. As shown, the left and right fork members 40 are
substantially identical one to the other. Accordingly, these and other
components
that are duplicated one on each side of the front bicycle wheel 22, are each
indicated by a single reference numeral, for the sake of clarity.
When the steering spindle 26 is turned by the handle bars (not shown) of the
bicycle 24, the hub member 30, the left and right fork members 40, and
ultimately
the front bicycle wheel 22 rotate therewith so as to permit steering of the
bicycle
24.
Left and right trailing arms 50 are pivotally mounted with one trailing arm
50 on each of the left and right fork members 40, respectively, by means of
conventional bolts 52 and co-operating nuts (not shown), or by any other
suitable
mounting means for pivotal movement of each trailing arm 50 about a common
pivot axis C. Each of the left and right trailing arms 50 is about 10 cm to 15
cm
long, with the distance along the trailing arms 50 from the common pivot axis
C to
the displaceable axis of rotation R being between about 5 cm and 15 cm -
typically,
about 10 to 15 cm - and preferably about 12 cm. The common pivot axis C is
oriented generally parallel to the displaceable axis of rotation R of the
front bicycle
wheel 22, and also oriented generally perpendicularly to the steering axis S.
The
common pivot axis C is also disposed forwardly of the steering axis S, so that
the
left and right trailing arms 50 can rotate rearwardly toward the steering axis
S, as
will be discussed in greater detail hereafter.
A bicycle wheel mounting means comprising a pair of mounting sockets 60
disposed one on each of the left and right trailing arms 50, permits mounting
of the
front bicycle wheel 22 on the left and right trailing arms 50 by means of an
axle 23
CA 02247776 1998-09-25
and co-operating nuts 25. Typically, an oversize axle is employed. The front
bicycle wheel 22 is mounted on the left and right trailing arms 50 such that
the
front bicycle wheel 22 rotates about the displaceable axis of rotation R. It
can be
seen that the displaceable axis of rotation R moves as the left and right
trailing arms
50 pivot about their common pivot axis C. When the front wheel 22 is mounted
on
the left and right trailing arms 50, the left and right trailing arms 50 are
concurrently
pivotally moveable between a forward position as shown in Figure 4A, and a
trailing position as shown in Figure 4B. When the left and right trailing arms
are
in their respective forward positions, the displaceable axis of rotation R of
the front
bicycle wheel 22 mounted on the front fork and trailing arm assembly 20 is
disposed forwardly of the steering axis S by a distance of between about 2 cm
to
8 cm, and preferably about 5 cm. Further, the displaceable axis of rotation R
of the
front bicycle wheel 22 is between the steering axis S and the common pivot
axis C,
when the left and right trailing arms 50 are in their forward position. When
the left
and right trailing arms are in their respective trailing positions, the
displaceable axis
of rotation R of the front bicycle wheel 22 mounted on the front fork and
trailing
arm assembly 20 is disposed closer to the steering axis S, and preferably very
near
or even on the steering axis S, than is the case when the left and right
trailing arms
50 are in their respective forward positions. The displaceable axis of
rotation R is
also displaced vertically closer to the common pivot axis when the left and
right
trailing arms 50 are in their respective trailing positions than when in their
respective forward positions.
The left and right trailing arms 50 are disposed along a main axis M, which
main axis M extends from, and passes through, the common pivot axis C to the
displaceable axis of rotation R. In the preferred embodiment, the main axis M
of
the left and right trailing arms 50 is disposed at an angle of about 5°
with respect
the horizontal, when the left and right trailing arms 50 are in their
respective trailing
positions.
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CA 02247776 1998-09-25
A variable length shock absorbing means 70, comprising an upper
component 72 securely attached to the hub member 30 and a lower component 74
depending from the upper component 72. The upper component 72 and the lower
component 74 are slidably engaged one with the other for relative movement
between an extended configuration, as can be seen in Figure 4A, and a
compressed
configuration, as can be seen in Figure 4B. In the preferred embodiment, the
lower
component 74 of the variable length shock absorbing means 70 can travel with
respect to the upper component 72 by a distance of slightly greater than 15
cm, as
dictated by the necessity of a suspension system of a bicycle, such as a
mountain
bicycle, to absorb severe impact during riding. The variable length shock
absorbing
means 70 further comprises a fluidic damper 76 operatively disposed between
the
upper component 72 and the lower component 74, so as to provide a physical
resistance to the relative movement of the upper component 72 and the lower
component 74 between their extended configuration and their compressed
configuration.
A linkage arm 80 having a top end 82 and a bottom end 84, is pivotally
mounted at its bottom end 84 to a selected one of the left and right trailing
arms 40
by conventional mounting means such as a bolt 81 extending through apertures
(not
shown) in the selected one of the left and right trailing arms 50 and the
linkage arm
80, retained therein by a co-operating nut (not shown). The linkage arm 80 is
thereby pivotally mounted for pivotal movement about a linkage arm lower axis
B,
as the left and right trailing arms SO pivot about their common pivot axis C.
Preferably, the aperture disposed on the selected one of the left and right
trailing
arms 50, and therefore the linkage arm lower axis B, is positioned between the
common pivot axis C and the displaceable axis of rotation R.
The linkage arm 80 is also pivotally mounted at its top end 82 to the lower
component 74 of the variable length shock absorbing means 70 for pivotal
movement about a linkage arm upper axis U, with such pivotal movement
occurring
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CA 02247776 1998-09-25
when the left and right trailing arms 50 pivot about their common pivot axis
C. It
can be seen in Figures 4A and 4B that the linkage arm upper axis B and the
linkage
arm lower axis U are substantially parallel to the displaceable axis of
rotation R.
Such pivotal mounting of the linkage arm 80 at its top end 82 to the lower
component 74 of the variable length shock absorbing means 70 and at its bottom
end 84 to the selected one of the left and right trailing arms 50, permits the
necessary angular movement of the linkage arm 80 with respect to the variable
length shock absorbing means 70, so as to accommodate the pivotal movement of
the left and right trailing arms 50 when the front bicycle wheel 22 is forced
upwardly during riding of the bicycle 24. Such angular movement of the linkage
arm 80 permits the necessary travel of 15 cm, or even more, of the lower
component 74 with respect to the upper component 72, as required to absorb
large
bumps, as will be discussed in greater detail hereafter.
A spring biasing means 90 in the form of a coil spring is mounted between
the upper component 72 and the lower component 74 of the variable length shock
absorbing means 70, so as to bias the variable length shock absorbing means 70
to
its extended configuration, and thereby also bias the left and right trailing
arms 50
to their respective forward positions.
In use, it is necessary that the suspension of the bicycle 24, especially the
stability maintaining shock absorbing bicycle front fork and trailing arm
assembly
20, permit vertical travel of the displaceable axis of rotation R of the front
bicycle
wheel 22, such that the change in vertical distance between the displaceable
axis of
rotation R and a fixed point on the hub member 30 is decreasable by at least
15 cm,
when the left and right trailing arms are pivotally moved from their
respective
forward positions to their respective trailing positions, as indicated by
arrow C, such
as when a bump is encountered by the front wheel 22. The left and right
trailing
arms 50 are pivotally moved from their forward position, as can be seen in
Figure
4A, to their trailing position, as can be seen in Figure 4B, whereat the
displaceable
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CA 02247776 1998-09-25
axis of rotation R is near or on the steering axis S. Also, the linkage arm 80
is
pivotally moved so as to pivot in a direction indicated by arrow D about the
linkage
arm upper axis U. Further, the linkage arm 80 pushes upwardly on the lower
component 74 of the variable length shock absorbing means 70, which shock
absorbing means 70 is forced to its compressed configuration, so as to absorb
the
impact of the relative upward movement of the front bicycle wheel 22. The
angle
H of the steering axis S is correspondingly increased, by a few degrees, when
the
front bicycle wheel 22 is in the position as shown in Figure 4B. Accordingly,
as
can be seen in Figure 3, at arrow A, the potential stability of the bicycle 24
would
decrease. Quite unexpectedly, in order to compensate for this potential
decrease in
stability, the movement of the left and right trailing arms 50 permits the
displaceable
axis of rotation R to be near the steering axis S, which decreases the front
fork
offset X. As can be seen in Figure 3, at arrow E, decreasing the relative
front
projection X compensates for the potential loss of stability due to the change
in head
angle, thereby allowing the bicycle 24 to remain stable. Such pivotal movement
of
the left and right trailing arms 50 to provide sufficient decrease in the
relative front
projection X, for large decreases (in the order of 15 cm) in the vertical
distance
between the displaceable axis of rotation R and a fixed point on the hub
member
30 can only be accomplished by means of a linkage arm 80 that pivots at both
its
bottom end 84 and its top end 82.
In a second preferred embodiment, as is shown in Figures SA and SB, a
variable length shock absorbing linkage arm 100 can replace the variable
length
shock absorbing means 70 and the linkage arm 80 of the first preferred
embodiment
of Figures 4A and 4B. The variable length shock absorbing linkage arm 100
comprises an upper component 102 having a top end 104 and a bottom end 106,
and a lower component 108 having a top end 110 and a bottom end 112. The upper
component 102 and the lower component 108 are slidably engaged one with the
other for relative movement between an extended configuration and a compressed
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CA 02247776 1998-09-25
configuration. The upper component 102 is pivotally mounted at its top end 104
on the hub member 30 for pivotal movement about a linkage arm upper axis U.
The lower component 108 is pivotally mounted at its bottom end 112 to a
selected
one of the left and right trailing arms 50, for pivotal movement about a
linkage arm
lower axis B. The linkage arm upper axis U and linkage arm lower axis B are
substantially parallel to the displaceable axis of rotation R. In a manner
similar to
that of the first preferred embodiment, the variable length shock absorbing
linkage
arm 100 further comprises a fluidic damper 114 operatively disposed between
the
upper component 102 and the lower component 108. Preferably, the vertical
distance between the displaceable axis of rotation R and a fixed point F on
the hub
member 30 is decreasable by at least 15 cm, when the left and right trailing
arms
move from their respective forward positions to their respective trailing
positions,
by means of compression of the variable length shock absorbing linkage arm
100.
The stability of a bicycle having the stability maintaining shock absorbing
bicycle front fork and trailing arm assembly 20, is maintained throughout
movement
of the left and right trailing arms 50 from their respective forward positions
to their
respective trailing positions, as is shown by curve G in Figure 6, as compared
to a
conventional telescopic front fork bicycle, as is shown by curve N in Figure
6.
Other modifications and alterations may be used in the design and
manufacture of the apparatus of the present invention without departing from
the
spirit and scope of the accompanying claims.
