Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02719296 2010-10-29
MULTI-STAGE TELESCOPIC SHOCK ABSORBER
FIELD
The present disclosure relates to suspension elements and shock absorbers,
such as
used in vehicle suspension systems, to dampen and smooth unwanted vibrations
and
shocks that occur as the vehicle travels over varying terrain.
SUMMARY
The present inventors have recognized that the prior art does not adequately
provide the suspension reaction forces desired when shock forces are applied
to the
vehicle component to which the suspension element or shock absorber is
mounted. The
present inventors endeavored to provide a multi-stage suspension element or
shock
absorber which provides spring and damping characteristics that will enhance
the ride
comfort, handling and ground holding capability of the vehicle when subjected
to
changeable driving conditions.
In one example disclosed herein, a multi-stage telescopic suspension element
includes first and second tubular shock bodies serially interconnected
together to provide
telescopic movement relative to one another. The shock bodies include a piston
arrangement slidably mounted therein to define a number of chambers each
containing at
least one of damping and spring elements for enabling damping of shock forces
applied to
the suspension element. One of the shock bodies has an end provided with a
piston which
is slidably mounted with respect to the other of the shock bodies, and an
internal floating
piston is slidably mounted with respect to the one of the shock bodies.
The multi-stage telescopic suspension element includes a first tubular shock
having
one end which is closed by a first end cap and an opposite end which is open.
A second
tubular shock body has one end provided with the piston which is slidably
mounted within
the first tubular shock body, and an opposite end closed by a second end cap.
The internal
floating piston is slidably mounted within the second tubular shock body
between the
piston and the second end cap. A first fluid chamber is defined by the first
tubular shock
body, the first end cap, the one end of the second tubular shock body and the
piston. A
second fluid chamber is defined by the second tubular shock body, the one end
of the
second tubular shock body and the internal floating piston. A spring chamber
is defined
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by the second tubular shock body, the internal floating piston and the second
end cap. The
second end cap includes an adapter and an end connector which is adjustably
mounted
relative to the adapter.
In another example disclosed herein, a multi-stage telescopic suspension
element
includes a plurality of tubular shock bodies serially interconnected to
provide telescopic
movement relative to one another. The shock bodies include a piston
arrangement
slidably mounted therein to define a number of chambers each containing at
least one of
damping and spring elements for enabling damping of shock forces applied to
the
suspension element.
The multi-stage telescopic suspension element includes a first tubular shock
body
having one end which is closed by a first end cap and an opposite end which is
open. A
second tubular shock body has one end provided with a first piston and an
opposite end
which is open. A third tubular shock body has one end provided with a second
piston and
an opposite end closed by a second end cap. The one end of the second shock
body is
slidably mounted within the first shock body, and the one end of the third
shock body is
slidably mounted within the second shock body. At least a first chamber is
defined by the
first shock body, the first end cap and the one end of the second shock body.
At least a
second chamber is defined by the second shock body, the one end of the second
shock
body and the one end of the third shock body. At least a third chamber is
defined by the
third shock body, the one end of the third shock body and the second end cap.
The first, second and third chambers each have a first fluid, a second fluid
and a
third fluid, respectively, and the first and second pistons are provided with
valve
arrangements for permitting fluid flow therethrough. The open end of the first
shock body
is in sealed relationship with an outer surface of the second shock body, and
an open end
of the second shock body is in sealed relationship with an outer surface of
the third shock
body. A first circumferential passage is defined by the one end of the second
shock body,
the opposite end of the first shock body, an inner surface of the first shock
body and an
outer surface of the second shock body. The outer surface of the second shock
body is
formed with openings therethrough that are in communication with the valve
arrangement
of the first piston and the first circumferential passage so that fluid is
transferable between
the first chamber and the first circumferential passage. The one end of the
second shock
body includes a separator plate located adjacent the first piston on the
second shock body
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for preventing fluid communication between the first and second chambers. A
second
circumferential passage is defined by the one end of the third shock body, the
opposite end
of the second shock body, an inner surface of the second shock body and an
outer surface
of the third shock body. An outer surface of the third shock body is formed
with openings
therethrough that are in communication with the valve arrangement of the
second piston
and the second circumferential passage so that fluid is transferable between
the second
chamber and the second circumferential passage. The valve arrangement of the
second
piston permits communication of fluid between the second and third chambers.
A first internal floating piston is slidably mounted within the first chamber
of the
first shock body between the first end cap and the one end of the second shock
body. A
first spring chamber is defined by the first shock body, the first end cap and
the first
internal floating piston. The first spring chamber contains a compressible
spring medium
such as a gas spring. A first damping chamber is defined by the first shock
body, the first
internal floating piston and the one end of the second shock body. The first
damping
chamber contains a hydraulic fluid. A second internal floating piston is
slidably mounted
in the third chamber of the third shock body between the one end of the third
shock body
and the second end cap. A second spring chamber is defined by the third shock
body, the
second internal floating piston and the second end cap. The second spring
chamber
contains a compressible spring medium such as a gas spring. A second damping
chamber
is defined by the third shock body, the one end of the third shock body and
the second
internal floating piston. A second damping chamber contains a hydraulic fluid.
The
second chamber defines a third damping chamber containing hydraulic fluid. The
first end
cap has a passageway for establishing a charge of gas in the first spring
chamber. The
second end cap has a passageway for establishing a charge of gas in the second
spring
chamber. At least one valve arrangement includes a fastener formed with a hole
therethrough which permits communication of fluid between a pair of the
chambers. At
least the first internal floating piston has a structure which defines a first
volume of the
first spring chamber when mounted in one position, and defines a second volume
of the
first spring chamber greater than the first volume when mounted in a second
position.
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BRIEF DESCRIPTION OF THE DRAWINGS
Fig. I is a sectional view of a first exemplary multi-stage telescopic shock
absorber
in an extended position;
Fig. 2 is a view similar to Fig. 1 showing the shock absorber in a partially
compressed position;
Fig. 3 is a view similar to Fig. 2 showing the shock absorber in a near fully
compressed position;
Fig. 4 is an exploded sectional view of the three stages of the shock absorber
shown in Figs. 1-3;
Fig. 5 is an exploded elevational view of the three stages of the shock
absorber
similar to Fig. 4;
Fig. 6 is an exploded sectional view of all of the components of the shock
absorber;
Fig. 7 is a partial perspective view of the second stage of the shock absorber
showing a front side of the first piston having valving washers;
Fig. 8 is a perspective view of a rear side of the first piston without
valving
washers;
Fig. 9 is a perspective view of the third stage of the shock absorber showing
a front
side of a second piston without valving washers;
Fig. 10 is a perspective view of a rear side of the second piston without
valving
washers;
Figs. 1 I-13 are sectional views of the shock absorber similar to Figs. 1-3
with
certain modifications made thereto; and
Figs. 14-16 are sectional views of a second exemplary shock absorber in
respective
extended, partially compressed and near fully compressed positions.
DETAILED DESCRIPTION
For purposes of promoting an understanding of the principles of the invention,
reference will now be made to the examples illustrated in the drawings and
described in
the following written specification. It is understood that no limitation to
the scope of the
invention is thereby intended. It is further understood that the present
invention includes
any alterations and modifications to the illustrated example and includes
further
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applications of the principles of the invention as would normally occur to one
skilled in
the art to which this invention pertains.
Overview
Referring now to the drawings, the present disclosure describes a multi-stage
suspension element in the form of a shock absorber 10 that is particularly
useful in, but not
limited to, a recreational vehicle, such as a snowmobile or all-terrain
vehicle (ATV),
which is typically subjected to travel over rough and varying terrain.
As seen in Figs. 1-5, the shock absorber 10 includes a first stage 12, a
second stage
14 and a third stage 16 telescopically interconnected together, and adapted to
be
positioned in a vehicle suspension for movement between extended and variably
compressed positions to absorb or dampen shocks and vibrations during vehicle
use.
The exemplary shock absorber 10 includes an arrangement of internal floating
pistons, pistons or valving members, chambers and passages for holding
hydraulic fluid or
gas. The shock absorber 10 illustrated is configured to act as a combination
spring and
damper, but may also act independently as a spring or damper. Opposite ends of
the shock
absorber 10 are provided with pivotal connection end caps which are adapted to
be
secured to various support elements such as located on the vehicle suspension.
The end
caps move closer to each other when a shock force is applied to the shock
absorber, and
will normally move apart when the shock force is removed and a spring force is
provided.
Two reaction forces (when configured as a spring and a damper) will result
when a shock
force is applied as the second stage 14 will nest in the first stage 12, and
the third stage 16
will nest in the second stage 14. Relative displacement of the stages 12 and
14 is normally
dependent upon gas pressure in the first and third stages 12 and 16,
respectively.
Hydraulic fluid will flow through the valving pistons when stages 14 and 16
are displaced
into stages 12 and 14, respectively. The pistons are provided with valving
arrangements
that restrict hydraulic fluid flow and generate damping forces dependent upon
velocity.
Hydraulic fluid passed through the pistons is displaced into circumferential
passages and
fill volumes of certain damping chambers that reside between the internal
floating pistons
and the pistons to enable movement thereof. The floating pistons have gas
charges (or
other spring forces) preset in spring chambers on sides opposite the fill
volumes such that
a restoring force is created as the gas (or spring) is compressed. Upon
damping of the
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applied shock force, the restoring force will enable the stages 12, 14 and 16
to assume
their original extended position.
First Exemplary Embodiment
Referring now to Fig. 6, as well as Figs. 1-5, the first stage 12 of shock
absorber 10
is generally constructed of a metal such as aluminum in the form of a hollow,
tubular
cylindrical shaft 18 defining a first shock body. The shaft 18 has one end
provided with
external threads 20, and an opposite end 21 formed with a number of adjacently
disposed
circular recesses 22, 24, and 26. A first closed end cap 28 has a circular
recess 30 for
receiving and retaining a sealing O-ring 32 therein, and a hole 34 for
receiving a ball joint
36 retained in place by a snap ring 38. The end cap 28 has internal threads 40
that enable
the end cap 28 to be screwthreaded onto threads 20 and sealed by means of the
O-ring 32
on shaft 18. The end cap 28 also has a passageway 42 that opens into the
interior of shaft
18 and is in communication with a fill valve 44 (Fig. 5). Opposite the closed
end cap 28,
the circular recesses 22, 24 and 26, respectively, receive and retain a wear
ring 46, a quad
ring 48 and a wiper 50. A first internal floating piston 52 has an external
grooved surface
provided with a pair of wear rings 54, 56 positioned on opposite sides of a
fluid-sealing
quad ring 58. The internal floating piston 52 has an internal transverse wall
60 formed
with a throughhole 62, one side of which receives a first plug screw 64. The
internal
floating piston 52 is mounted for sliding and sealed movement back and forth
along the
inner surface of shaft 18.
The second stage 14 of shock absorber 10 is also preferably constructed of
aluminum and includes a hollow, tubular cylindrical shaft 66 defining a second
shock
body. The shaft 66 has a diameter which is smaller than the diameter of shaft
18, and has
a radially enlarged end 68 that defines a recess 70 that is provided
externally with a wear
ring 72 thereon. An outer surface of shaft 66 is formed with a number of
openings 74, and
a separator plate 76 with a central hole 78 extends across the interior of
shaft 66. A first
piston or valving element 80 has an O-ring 82 externally retained thereon and
is formed
therethrough with a bypass hole 83 and a central hole 84 which is aligned with
central hole
78 in separator plate 76.
As seen in Fig. 7, one side of piston 80 is formed with several circular holes
86 and
several slotted channels 88. As seen in Fig. 8, the other side of piston 80 is
formed with
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several slotted channels 90 in communication with holes 86 and several
circular holes 92
in communication with slotted channels 88. Each side of piston 80 includes a
number of
flexible washers or disks 94 which typically cover at least some of the holes
86, 92 and
channels 88, 90. The washers 94 are constructed to flex when a predetermined
amount of
pressure is applied thereto and, as will be appreciated hereafter, are used to
control fluid
flow during compression and extension of shock absorber 10. Washers 94 may
vary in
thickness and diameter to provide differing metering characteristics. The
piston 80 with
the washers 94 on each side thereof is positioned in the recess 70, and
retained in the
enlarged end 68 of shaft 66 adjacent separator plate 76 by a bolt 96 which is
passed
through holes 78 and 84 and receives lock nut 98 thereon. Together, the
openings 74,
holes 86, 92, the channels 88, 90 and the washers 94 define a valve
arrangement for
variably controlling fluid flow in the shock absorber 10.
Opposite the radially enlarged end 68, the shaft 66 is provided with internal
threads
100, and a rubber sleeve or bumper 102 is positioned externally on shaft 66
outside
threads 100. A cap 104 with a central opening is formed with adjacent internal
recesses
106, 108, 110 for respectively receiving a wear ring 112, a quad ring 114, and
a wiper 116.
A laterally extending portion 117 of cap 104 has threads 118 formed externally
thereon
along with a groove 120 for receiving an O-ring 122. Cap 104 is screwthreaded
into
threads 100 of shaft 66 so that a radially enlarged portion of cap 104 abuts
an outer end of
rubber bumper 102 and an O-ring 122 provides a seal between the cap 104 and
the shaft
66. The radially enlarged end 68 of shaft 66 with its external wear rings 72
and internal
piston 80 is configured for sliding movement back and forth along the inner
surface of
shaft 18. The outer surface of shaft 66 slides back and forth along wear ring
46, quad ring
48 and wiper 50 so that it is in sealed relationship with the shaft 18.
The third stage 16 of shock absorber 10 is preferably constructed of aluminum
and
includes a hollow, tubular cylindrical shaft 124 defining a third shock body
which is
slidable through the cap 104. The shaft 124 has a diameter which is smaller
than the
diameter of shaft 66, and has a radially enlarged end 125 that is provided
internally with
threads 126 and externally with a groove 128 for receiving a wear ring 130. An
outer
surface of shaft 124 is formed with a series of openings 132 and an internal
recess 134 is
provided for retaining an O-ring 136. A second piston or valving element 138
has external
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threads 140 that are received in the internal threads 126 of shaft 124, and is
formed with a
central hole 142.
As seen in Fig. 9, one side of piston 138 is formed with several circular
holes 144
and several slotted channels 146. As seen in Fig. 10, the other side of piston
138 is formed
with several slotted channels 148 in communication with holes 144 and several
circular
holes 150 in communication with slotted channels 146. Each side of piston 138
includes
flexible washers or disks 152 which are comparable in structure and function
to disks 94.
A backup washer 154 is placed against the washer 152 on the other side of the
piston 138,
and has a central hole 156 aligned with central hole 142. A bolt 158 with a
bypass hole
160 formed longitudinally therethrough for metering fluid is passed through
the disks 152
and the holes 142 and 156, and threaded into a lock nut 162 positioned against
the backup
washer 154. Together openings 132, holes 144, 150, channels 146, 148 and
washers 152
define a valve arrangement for controlling fluid flow through the shock
absorber 10.
A second internal floating piston 164 is provided externally with a quad ring
166
and a wear ring 168. The internal floating piston 164 has a throughhole 170,
one side of
which receives a plug screw 172. Opposite the radially enlarged end 125, a
second closed
end cap 174 has an internal recess 176 for receiving a sealing 0-ring 178
therein, and
internal threads 180 which are screwthreaded onto the external threads 182 on
shaft 124.
End cap 174 is formed with a hole 184 similar to hole 34 for providing a
pivotal end
connection for the shock absorber 10 on the vehicle suspension. End cap 174
also is
provided with a fill valve 186 (Fig. 5) in communication with passageways 188
and 190
that open into the interior of shaft 124. The radially enlarged end 125 of
shaft 124 is
configured for sliding movement back and forth along the inner surface of
shaft 66. The
internal floating piston 164 is mounted for sliding and sealed movement back
and forth
along the inner surface of shaft 124. The outer surface of shaft 124 slides
back and forth
along wear ring 112, quad ring 114, and wiper 116.
In a typical use of the exemplary embodiment described above, the three stages
12,
14, 16 of the shock absorber 10 are slidably interconnected as shown in Figs.
1-3. With
end cap 28 unscrewed from shaft 18, and the open end of shaft 18 oriented
upwardly, the
internal floating piston 52 with plug screw 64 removed is positioned within
shaft 18. The
internal floating piston 52 will have a frictional fit with the inner surface
of the shaft 18.
A viscous damping fluid in the form of a hydraulic fluid or oil is poured into
the open end
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of vertically oriented shaft 18 such that oil will pass via throughhole 62
into a first
damping chamber A defined by the shock body 18, internal floating piston 52
and the
piston 80. Plug screw 64 is inserted in throughhole 62, and any excess oil is
removed
from the interior of shaft 18 to the left of internal floating piston 52. End
cap 28 is
screwthreaded and sealed onto the threads 20 of shaft so that a first spring
chamber B is
defined by the shock body 18, the end cap 28 and the internal floating piston
52.
With end cap 174 unscrewed from shaft 124 and the open end of shaft 124
oriented
upwardly, the internal floating piston 164 with plug screw 172 removed is
positioned
within shaft 124. The internal floating piston 164 will have a frictional fit
with the inner
surface of shaft 124. A damping fluid in the form of a hydraulic fluid or oil
is poured into
the open end of vertically oriented shaft 124 such that the oil will pass via
throughhole 170
into a second damping chamber C defined by the shock body 124, the internal
floating
piston 164 and the piston 138. Plug screw 172 is inserted in throughhole 170,
and any
excess oil is removed from the interior of shaft 124 to the right of internal
fluid piston 164.
End cap 174 is screwthreaded and sealed onto threads 182 of shaft 124 so that
a second
spring chamber D is defined by the shock body 124, the internal floating
piston 164, and
the end cap 174. A third damping chamber E is defined by the shock body 66,
the
separator plate 76 and the piston 138 in the end 128 of the shaft 124. The
third damping
chamber E is in communication with oil in damping chamber C by virtue of the
valve
arrangement in piston 138 and the bypass hole 160 in bolt 158. Separator plate
76 with
bolt 96 inserted therethrough prevents any communication between damping
chambers A
and E. In addition, upon compression of shock absorber 10 as seen in Figs. 2
and 3, a first
circumferential damping passage F is defined by the inner surface and the end
21 of shaft
18, and the outer surface and the end 68 of shaft 66. Damping passage F is in
communication with openings 74 formed in shaft 66 and oil in damping chamber A
which
can pass through piston 80. A second circumferential damping passage G is
defined by
the inner surface of shaft 66 and the outer surface and end 128 of shaft 124
and the portion
117 of cap 104. Damping passage G is in communication with the openings 132
formed
in shaft 124 and oil in damping chamber E will pass through piston 138. Spring
chambers
B and D are charged appropriately via fill valves 44, 186 with a compressible
medium in
the form of a gas spring, such as a CO2, air or nitrogen, to provide a desired
return or
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rebound force following compression and retraction of the second and third
stages 14 and
16, respectively.
Fig. 1 illustrates a shock absorber in a fully extended position without any
shock
force applied thereto. Figs. 2 and 3 depict the successive compression and
damping of the
second and third stages 14 and 16 when a shock force is applied to the shock
absorber 10.
During compression, the piston 80 slides to the left within the shock body 18
against the
oil in damping chamber A causing internal floating piston 52 to move towards
end cap 28
and compressing gas in the spring chamber B. As the piston 80 slides to the
left, some of
the oil in damping chamber A is transferred through the valve arrangement for
piston 80
including the openings 74 of shaft 66 and flows into the circumferential
passage F. As
piston 138 moves to the left within the shock body 66, some of the oil in
damping
chamber E passes through the valve arrangement for piston 138 including the
bypass hole
160 into damping chamber C pushing internal floating piston 164 to the right
towards end
cap 174 and compressing the gas in spring chamber D. Simultaneously, some of
the oil in
damping chamber E also flows through the openings 132 on shaft 124 and into
circumferential passage G. When the shock force has been dampened, the shock
absorber
10 assumes the substantially fully compressed position depicted in Fig. 3. It
should be
appreciated that metal-to-metal contact with the end 21 of shock body 18 and
the cap 104
of shock body 66 is prevented by the rubber bumper 102.
A rebound action follows the aforementioned compression of the shock absorber
10. During the rebound action, the gas compressed in spring chambers B and D
will
resiliently expand against internal floating pistons 52 and 164 causing the
shock absorber
to extend and return to the initial precompressed condition shown in Fig. 1.
As was the
case during compression, oil within the shock absorber will pass in a reverse
direction
through the pistons 80 and 138 as well as the openings 74 and 132 for return
to damping
chambers A, C and E.
It should be understood that damping in the shock absorber 10 may be changed
such as by providing different valve arrangements for the pistons 80 and 138,
by varying
the diameter of the hole 160 in bolt 158 or by altering the number and size of
the openings
74 and 132 in the shafts 66 and 124, respectively. The greater the degree to
which the
flow of damping fluid is restricted, the greater the damping forces that are
provided by the
shock absorber 10. Accordingly, a "soft" stroking action is afforded when the
flow of
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damping fluid in the shock absorber is relatively unrestricted. By contrast, a
"stiffer"
stroking action is obtained when there is increased restriction in the flow of
damping fluid
in the shock absorber 10.
Similarly, it should be appreciated that the rebound action in the shock
absorber 10
may be constructed to provide different return forces by varying the preset
gas pressures in
the spring chambers B and D. If desired, the volume of spring chamber B may be
enlarged such as by reversing the orientation of the interior floating piston
52 within shock
body 18. The enlargement of spring chamber B has been shown to provide a more
linear
spring rate for the rebound action of the shock absorber 10. It should also be
understood
that either or both of the spring chambers B and D could be alternatively
charged by using
one or more remote reservoirs that could include an internal floating piston.
Although the
exemplary embodiment utilizes a gas spring in each of the spring chambers B
and D, the
shock absorber 10 could also be suitably configured with a mechanical,
electrical,
magnetic or alternative spring.
It is contemplated that the three stage shock absorber 10 described herein may
have
more or less stages and that the lengths and diameters of the stages may be
varied in size
as desired for a particular application. Likewise, the shock absorber 10 may
be
constructed with fewer or greater than the internal floating pistons 52, 164,
the pistons 80
and 138, the chambers A, B, C, D, E and the passages F and G as described
above. If
desired, the shock absorber 10 may be constructed without the internal
floating pistons 52
and 164 thereby creating chambers between the piston 80 and the end cap 28,
and the
piston 138 and the end cap 174 which may be filled with oil and gas thereby
creating an
emulsion shock absorber.
Figs. 11-13 are similar in structure and function to the first exemplary
embodiment
described above except for the following modifications which are made to ease
machining
and assembly and improve versatility of the shock absorber 10. Separator plate
76 which
is formed integrally across the interior of shaft 66 adjacent end 68, as shown
in Figs. 1-6,
is replaced by a separate and non-integral separator plate 76a having a
central hole 78a.
Bolt 96 passes through hole 78a and hole 84 of piston 80 and receives lock nut
98 to
maintain separator plate 76a tightly against washer 94 and piston 80. When
fixed in place,
the separator plate 76a has a peripheral surface which is sealed against the
interior surface
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of hollow tubular shaft 66 by an O-ring 192 positioned in a groove formed in
the
peripheral surface.
The end cap 174 shown in Figs. 1-6 is replaced by a two piece assembly
comprised
of an adapter 194 and an end connector 196. Adapter 194 is grooved for
receiving a
sealing O-ring 178a therein, and is provided on an inner end thereof with
threads 198
which are screwthreaded onto external threads 182 of shaft 124. Adapter 194 is
formed
with a fill valve 200 having a passageway 202 that opens into the interior of
shaft 124 to
selectively charge chamber D with a compressible medium. Adapter 194 is
further formed
with an internal recess 204 that is internally threaded to receive threads 206
on an
extension 208 of the end connector 196. The end connector 196 is provided with
a ball
joint 210 and has a hole 212 for providing a pivotal end connection for the
shock absorber
10. The end connector 196 can vary in size and can be threadably adjusted as
desired to
change the length of the shock absorber 10 without disassembly thereof A lock
nut 214 is
threadably engaged on the extension 208 to lock the end connector 196 relative
to the
adapter 194.
Second Exemplary Embodiment
Referring now to Figs. 14-16, the present disclosure further contemplates a
two
stage shock absorber 10' having a hollow tubular cylindrical shaft 216
defining a first
shock body. One end of shaft 216 has a closed end cap 218 and an opposite end
of shaft
216 has an open cap 220 for slidably receiving a hollow tubular cylindrical
shaft 222
defining a second shock body. The shaft 222 has an outer surface formed with a
series of
openings 224, and has a radially enlarged end 226 provided with a piston or
valve element
228. Opposite sides of the piston 228 include flexible washers and disks 230
and a backup
washer 232 which are comparable in structure and function to disks 94 and 152.
A bolt
234 with a bypass hole 236 formed longitudinally therethrough for metering
fluid is
passed through piston 228, disks 230 and washer 232 and threaded into a lock
nut 238. An
internal floating piston 240 having a plug screw 242 is mounted for sliding
and sealed
movement back and forth along the inner surface of shaft 222. Opposite the
radially
enlarged end 226, the shaft 222 has an open end 244 closed by a second end cap
defined
by the adapter 194 and end connector 196 as described above.
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A first fluid damping chamber H is defined by the shock body 216, the end cap
218
and the end 226 of the shock body 222 having piston 228 mounted therein. A
second fluid
damping chamber I is defined by the shock body 222, the end 226 of the shock
body 222
having piston 228 mounted therein and internal floating piston 240. A spring
chamber J is
defined by the shock body 222, the internal floating piston 240 and the second
end cap
defined by adapter 194 and end connector 196. As seen in Figs. 15 and 16, a
circumferential damping passage K is defined by the inner surface and end cap
220 of
shock body 216 and the outer surface and end 226 of the shock body 222.
Damping
passage K is in communication with openings 224 formed in shock body 222 and
damping
fluid, such as oil, provided in damping chamber H which can pass through
piston 228 and
washers 230. Damping chamber I is designed to receive damping fluid, such as
oil, and
spring chamber J is charged appropriately via fill valve 200 with a
compressible medium
in the form of a gas spring, such as C02, air or nitrogen, to provide a
desired return or
rebound force following compression and retraction of the two stage shock
absorber 10'.
Fig. 14 illustrates shock absorber 10' in a fully extended position without
any
shock force applied thereto. Figs. 15 and 16 depict the successive compression
and
damping when a shock force is applied to the shock absorber 10'. During
compression,
the piston 228 slides to the left within the shock body 216 against the oil in
damping
chamber H. As the piston 228 slides to the left, some of the oil in damping
chamber H is
transferred through the valve arrangement for piston 228 including the
openings 224 of
shock body 222 and flows into circumferential damping passage K.
Simultaneously, some
of the oil in damping chamber H passes through the piston 228 including the
bypass hole
236 into damping chamber I pushing internal floating piston 240 to the right
towards
adapter 194 and compressing the gas in spring chamber J. When the shock force
has been
dampened, the shock absorber 10' assumes the substantially fully compressed
piston
depicted in Fig. 16.
A rebound action follows the aforementioned compression of shock absorber 10'.
During the rebound action, gas in spring chamber J will resiliently expand
against internal
floating piston 240 causing the shock absorber 10' to extend and return to the
condition
shown in Fig. 14. Oil within the shock absorber 10' will pass in a reverse
direction from
damping chamber I and passage K through the piston 228 and openings 224 for
return to
damping chamber H.
13
CA 02719296 2010-10-29
This written description uses examples to disclose the invention, including
the best
mode, and also to enable any person skilled in the art to make and use the
invention. The
patentable scope of the invention is defined by the claims, and may include
other examples
that occur to those skilled in the art. Such other examples are intended to be
within the
scope of the claims, if they have structural elements that do not differ from
the literal
language of the claims, or if they include equivalent structural elements in
substantial
differences from the literal language of the claims.
Various alternatives and embodiments are contemplated as being within the
scope
of the following claims, particularly pointing out and distinctly claiming the
subject matter
regarded as the invention.
14
