U.S. patent application number 16/910730 was filed with the patent office on 2020-10-08 for apparatus and methods for a vehicle shock absorber.
This patent application is currently assigned to Fox Factory, Inc.. The applicant listed for this patent is Fox Factory, Inc.. Invention is credited to Bryan Wesley Anderson, Mario Galasso, Dennis K. Wootten.
Application Number | 20200318705 16/910730 |
Document ID | / |
Family ID | 1000004915642 |
Filed Date | 2020-10-08 |
United States Patent
Application |
20200318705 |
Kind Code |
A1 |
Galasso; Mario ; et
al. |
October 8, 2020 |
APPARATUS AND METHODS FOR A VEHICLE SHOCK ABSORBER
Abstract
A method and apparatus for a vehicle shock absorber comprising a
main damper cylinder, a first reservoir and a second reservoir. One
embodiment includes a first operational mode where both reservoirs
are in fluid communication with the cylinder. In a second
operational mode, only one reservoir communicates with the cylinder
during fluid evacuation from the cylinder. In each mode, rebound
from either or both reservoirs may travel through a single,
user-adjustable metering device.
Inventors: |
Galasso; Mario; (Sandy Hook,
CT) ; Wootten; Dennis K.; (Milford, NH) ;
Anderson; Bryan Wesley; (Santa Cruz, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Fox Factory, Inc. |
Braselton |
GA |
US |
|
|
Assignee: |
Fox Factory, Inc.
Braselton
GA
|
Family ID: |
1000004915642 |
Appl. No.: |
16/910730 |
Filed: |
June 24, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16361954 |
Mar 22, 2019 |
10704640 |
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16910730 |
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15808645 |
Nov 9, 2017 |
10240655 |
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16361954 |
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14993861 |
Jan 12, 2016 |
9816578 |
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15808645 |
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14330850 |
Jul 14, 2014 |
9255620 |
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14993861 |
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12794219 |
Jun 4, 2010 |
8807542 |
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14330850 |
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61184763 |
Jun 5, 2009 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16F 9/065 20130101;
F16F 9/06 20130101 |
International
Class: |
F16F 9/06 20060101
F16F009/06 |
Claims
1. A shock absorber comprising: a main damper cylinder having a
variable volume portion with fluid therein; a first reservoir and a
second reservoir; a first fluid flow path extending from the
variable volume portion to a first valve; a second fluid flow path
extending from the first valve to the first reservoir; a third
fluid flow path extending from the first valve to the second
reservoir; a fourth fluid flow path extending between the first
reservoir and the second reservoir independent of the first, second
and third fluid flow paths, the fourth fluid flow path having a
fourth fluid flow path valve positioned therein to selectively open
and close the fourth fluid flow path, wherein the shock absorber is
operable in a first operational mode wherein fluid travels only
from the variable volume portion of the main damper cylinder to the
first reservoir utilizing the first fluid flow path and the second
fluid path and, fluid travels from the first reservoir to the
second reservoir utilizing only the fourth fluid flow path, said
shock absorber further operable in a second operational mode
wherein fluid travels from the variable volume portion of the main
damper cylinder to the second reservoir utilizing the first fluid
flow path and the third fluid flow path, said shock absorber
further operable in a third operational mode wherein said fluid is
prevented from travelling from said variable volume portion of said
main damper cylinder to said first reservoir and said fluid is also
prevented from travelling from said variable volume portion of said
main damper cylinder to said second reservoir; and user-accessible
controls coupled to said shock absorber, said user-accessible
controls for selecting between said first operational mode, said
second operational mode, and said third operational mode, wherein
said first operational mode is a full-travel mode, and said third
operational mode is a lock-out mode.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of and claims
the benefit of co-pending U.S. patent application Ser. No.
16/361,954, filed on Mar. 22, 2019, entitled "APPARATUS AND METHODS
FOR A VEHICLE SHOCK ABSORBER" by Mario Galasso et al., having
Attorney Docket No. FOX-0038US.CON4, which is incorporated herein,
in its entirety, by reference and is assigned to the assignee of
the present application.
[0002] The U.S. application Ser. No. 16/361,954 is a continuation
application of and claims the benefit of U.S. patent application
Ser. No. 15/808,645, filed on Nov. 9, 2017, now U.S. Pat. No.
10,240,655, entitled "APPARATUS AND METHODS FORA VEHICLE SHOCK
ABSORBER" by Mario Galasso et al., having Attorney Docket No.
FOX-0038US.CON3, which is incorporated herein, in its entirety, by
reference and is assigned to the assignee of the present
application.
[0003] The U.S. application Ser. No. 15/808,645 is a continuation
application of and claims the benefit of co-pending U.S. patent
application Ser. No. 14/993,861, filed on Jan. 12, 2016, now U.S.
Pat. No. 9,816,578, entitled "APPARATUS AND METHODS FOR A VEHICLE
SHOCK ABSORBER" by Mario Galasso et al., having Attorney Docket No.
FOX-0038US.CON2, which is incorporated herein, in its entirety, by
reference and is assigned to the assignee of the present
application.
[0004] The U.S. application Ser. No. 14/993,861 is a continuation
application of and claims the benefit of U.S. patent application
Ser. No. 14/330,850, filed on Jul. 14, 2014, now U. S. Pat. No.
9,255,620, entitled "APPARATUS AND METHODS FOR A VEHICLE SHOCK
ABSORBER" by Mario Galasso et al., having Attorney Docket No.
FOX-0038US.CON, which is incorporated herein, in its entirety, by
reference and is assigned to the assignee of the present
application.
[0005] The U.S. application Ser. No. 14/330,850 application is a
continuation application of and claims the benefit of patented U.S.
patent application Ser. No. 12/794,219, filed on Jun. 4, 2010, now
U.S. Pat. No. 8,807,542, entitled "APPARATUS AND METHODS FOR A
VEHICLE SHOCK ABSORBER" by Mario Galasso et al., having Attorney
Docket No. FOXF/0038US, which is incorporated herein, in its
entirety, by reference and is assigned to the assignee of the
present application.
[0006] The U.S. Pat. No. 8,807,542 claims priority to and the
benefit of U.S. Provisional Patent Application 61/184,763 filed on
Jun. 5, 2009, entitled "METHODS AND APPARATUS FOR DUAL CHAMBER
SUSPENSION" by Mario Galasso et al., having Attorney Docket No.
FOXF/0038L, which is incorporated herein, in its entirety, by
reference and is assigned to the assignee of the present
application.
BACKGROUND OF THE INVENTION
Field of the Invention
[0007] Embodiments of the present invention generally relate to a
suspension system, more particularly, a shock absorber with
multiple reservoir chambers (IFPs), especially one permitting
selective communication between the reservoirs and a main damper
chamber.
Description of the Related Art
[0008] Integrated damper/spring vehicle shock absorbers often
include a damper body surrounded by a mechanical spring. The damper
consists of a piston and shaft telescopically mounted in a fluid
filled cylinder. The purpose of the damper is to control the speed
at which the shock absorber operates. The mechanical spring
provides resistance to shock events and may be a helically wound
spring that surrounds the damper body. Various integrated shock
absorber configurations are described in U.S. Pat. Nos. 5,044,614,
5,803,443, 5,553,836 and 7,293,764; each of which is herein
incorporated in its entirety by reference. A shock absorber of U.S.
Pat. No. 7,293,764 is shown herein as FIG. 1. As shown, the shock
absorber 10 comprises a damper assembly 15 consisting of a chamber
18 housing a piston (not shown) and rod 20 and a helical spring 25
disposed on the damper in a manner whereby the spring and damper
operate together. The shock absorber is attached via eyeholes 30,
35 to separate portions of a vehicle (not shown) and the shock
operates when there is relative movement between those
portions.
[0009] Various arrangements permit aspects of the shock absorber to
be adjusted or changed by an end user. For example, U.S. Pat. No.
5,044,614 ("614 patent") shows a damper body carrying a thread 42.
A helical spring 18 surrounds the damper body. The compression in
the helical spring 18 may be pre-set by means of a nut 48 and a
lock nut 50. The nut 48 may be translated axially relative to the
body ("tube") 16 and thread 42 by rotating the nut 48 around the
threaded sleeve 42. Rotation of the nut 48 in a given direction
(e.g. clockwise as viewed from end 44 for a right hand thread 42)
will cause the nut to move toward the retainer clip 26 thereby
compressing spring 18 between the nut 48 and the retainer clip 26.
Once the spring 18 is in a desired state of compression, lock nut
50 is rotated, using a wrench, up against nut 48 and tightened in a
binding relation therewith.
[0010] Some shock absorbers utilize gas as a spring medium in place
of, or in addition to, mechanical springs. Gas spring type shock
absorbers, having integral dampers, are described in U.S. Pat. Nos.
6,135,434, 6,360,857 and 6,311,962, each of which is herein
incorporated in its entirety by reference. U.S. Pat. No. 6,360,857
shows a shock absorber having selectively adjustable damping
characteristics. U.S. Pat. No. 7,163,222, which is incorporated
herein in its entirety by reference, describes a gas sprung front
shock absorber for a bicycle (a "fork") having a selective "lock
out" and adjustable "blow off" function.
[0011] The spring mechanism (gas or mechanical) of some shock
absorbers is adjustable so that it can be preset to varying initial
states of compression. In some instances, the shock spring (gas or
mechanical) may comprise different stages having varying spring
rates thereby giving the overall shock absorber a compound spring
rate depending varying through the stroke length. In that way the
shock absorber can be adjusted to accommodate heavier or lighter
carried weight, or greater or lesser anticipated impact loads. In
vehicle applications, including motorcycle and bicycle applications
and particularly off-road applications, shock absorbers are
pre-adjusted to account for varying terrain and anticipated speeds
and jumps. Shocks are also adjusted according to certain rider
preferences (e.g. soft-firm).
[0012] A type of integrated spring I damper shock absorber, having
a gas spring, is shown in FIG. 28, for example, of U.S. Pat. No.
7,374,028, which is incorporated herein in its entirety by
reference. The shock shown in FIG. 28 of the '028 patent also
includes an "adjustable intensifier assembly 510." That intensifier
or "reservoir" accepts damping fluid from chamber 170 as the fluid
is displaced from that chamber by the incursion of rod 620 into
chamber 170 during a compression stroke of the shock. The
intensifier valve assembly regulates flow of damping fluid into and
out of the reservoir, and an embodiment of the valve assembly is
shown in FIG. 17 of the patent.
[0013] In some instances, reservoir portions of dampers are
separate components whereby a separate chamber is provided for
fluid expelled from the main chamber. A damper with such a remote
reservoir is illustrated in FIG. 9 of the '028 patent incorporated
herein. Other suspension systems use multiple, separate
reservoir-type chambers that divide the usable dampening capability
of the shock. In these designs, fluid is pushed from the main
dampening cylinder and with valving, the reservoir chambers are
utilized in various ways. By using one or both chambers, the travel
available in the shock can be determined by a user. Configurations
of multiple reservoir-type shocks are shown in U.S. Pat. No.
7,219,881, which is incorporated herein in its entirety by
reference. The presently available dual reservoir designs have
drawbacks. For example, utilization of both reservoirs is achieved
solely by use of two separate and distinct paths between the main
chamber and each of the reservoirs. Because each path has its own
metering devices, especially in the rebound direction, there is
always a potential of one of the reservoir chambers to lose fluid
and "crash" when the metering devices are set differently.
[0014] What is needed is a multiple reservoir suspension system
that ensures that each reservoir retains sufficient operating
fluid. What is needed is a multiple reservoir system having
simplified controls.
SUMMARY OF THE INVENTION
[0015] The present invention generally relates to a vehicle shock
absorber comprising a main damper cylinder, a first reservoir and a
second reservoir (although the principles herein may be extended to
a third or more reservoirs as well). In one embodiment, a first
operational mode includes a fluid path between the cylinder,
optionally via a valve, and a first reservoir and then a path
between the first and a second reservoir. In a second operational
mode, a fluid path is utilized between the cylinder, optionally via
a valve, and one of the reservoirs, the path excluding the other
reservoir. Operation between the modes is user selectable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] So that the manner in which the above recited features can
be understood in detail, a more particular description may be had
by reference to embodiments, some of which are illustrated in the
appended drawings. It is to be noted, however, that the appended
drawings illustrate only typical embodiments of the invention and
are therefore not to be considered limiting of its scope, for the
invention may admit to other equally effective embodiments.
[0017] FIG. 1 is a perspective view of a shock absorber including a
damper and a spring.
[0018] FIG. 2 is a schematic view of a damper with two
reservoirs.
[0019] FIG. 3 is a section view of a Schrader-type valve.
[0020] FIG. 4 is a section view of a Schrader-type valve.
[0021] FIG. 5 is a section view of a Schrader-type valve.
[0022] FIG. 6 is a section view showing a damper cylinder with a
valve adjacent thereto and fluid paths between the damper cylinder
and valve.
[0023] FIG. 7 is a section view showing a valve and two reservoirs
with fluid paths therebetween in a "full-travel" mode of the shock
absorber.
[0024] FIG. 8 is a section view showing the valve and two
reservoirs with fluid paths therebetween in a "half-travel"
mode.
[0025] FIG. 9 is a section view showing a rebound pathway for fluid
between the reservoirs.
DETAILED DESCRIPTION
[0026] FIG. 2 is a schematic view of a shock absorber embodiment
100 that utilizes a main damper 125 and two reservoir chambers or
Internal Floating Piston chambers (IFPs) 300, 400. Unlike the shock
of FIG. 1, the shock embodiment of FIG. 2 operates as a "pull
shock", which means the shock absorber gets pulled in tension to an
extended condition as the suspension mechanism driving the shock
reacts to compressive forces caused by terrain irregularities
(bumps that compress the rear wheel toward the bicycle frame).
Whether or not a shock absorber extends or compresses in response
to compressive terrain features is a function of the suspension
linkage in which the shock is mounted. In one embodiment, the oil
chamber and gas chambers of the shock are in reversed placement
relative to the main piston and shaft seal end of the main
cylinder. With a "push shock", on the other hand, the shock
absorber gets pushed to a shorter condition as the suspension
mechanism driving the shock accommodates compressive terrain
irregularities. Other than appearance and reversed operation, the
principles of pull and push shocks remain substantially the same
and the embodiments described and claimed herein are equally
intended for both.
[0027] In one embodiment of the invention, a shock absorber is
operatively mounted between an unsprung portion of a bicycle, such
as the swing arm and rear axle, and a sprung portion of the bicycle
such as the frame. A representative example embodiment of shock
absorber derives from the shock absorber shown in FIG. 28 of, and
elsewhere in, U.S. Pat. No. 7,374,028 which is incorporated herein
by reference.
[0028] In the embodiment of FIG. 2, the main damper 125 has a
piston 180 mounted on a shaft 185. The piston 180 is solid without
the typical passages formed therethrough for the passage of fluid
from one side of the piston 180 to the other side (although in some
embodiments the piston may also include damping passages and
valving). The shaft and piston assembly is fitted into a main
cylinder 178. The cylinder is divided into a fluid (e.g. damping
fluid, oil) chamber 188 and compressible fluid or gas (e.g. air,
nitrogen) chamber 189 and this division is created by the solid
piston, which seals on its OD with a seal such as an O-ring seal
190. The shaft 185 is also sealed where it extends a bulkhead of
the main cylinder 178 with O-ring seal 186. When the shaft is
pulled, the air chamber 189 within the cylinder becomes bigger
(increases in volume) and the fluid chamber 188 within the cylinder
becomes smaller. Fluid is pushed by the piston from the fluid
chamber 188, through a compression damping circuit that includes a
valve 200, and into one or both of the two IFP chambers 300, 400,
as will be described herein. The first chamber 300 and second 400
IFP chambers are also each separated into a fluid chamber 301, 401
and an gas (e.g. air) chamber 302, 402 by a floating piston 305,
405 of each chamber 300, 400. In each case the floating piston is
sealed within the chamber by a suitable seal such as an O-ring seal
306, 406. As fluid moves from the main cylinder fluid chamber 188
into the fluid chambers 301, 401, the IFP chambers 301, 401
increase in volume at the expense of the gas chamber 302, 402
volumes (as the gas chambers decrease in volume by movement of the
floating pistons).
[0029] In use, gas pressure in the gas chamber 189 of the main
cylinder 178 is adjustable using a fill valve 155. Gas pressure in
the IFPs 300, 400 is also user-adjustable. As shown in one
embodiment of FIG. 2, the gas volumes 302, 402 of the IFPs are in
fluid communication with a single fill valve 315 via a
communication path 311. In one embodiment, another valve 500
adjacent the fill valve 315, or integral therewith, is a
Schrader-type valve for filling the first and second IFP air
chambers 302, 402 to an equal pressure and then subsequently
maintaining isolation of chambers 302 and 402 one from the other
during use. The Schrader valve includes an axially movable stem
member depressible to communicate with the first chamber through a
first port and further depressible to communicate with the first
and second chambers through a second port. In this manner, a single
volume can be filled or preferably, both volumes, 302, 402 can be
filled to an equal pressure in a single action by the user. Such an
arrangement is shown and described in detail (see FIGS. 11, 12, 13)
in Patent Application Publication No. US 2009/0236807 A1, assigned
to the owner of the present invention, and that publication is
incorporated herein by reference in its entirety.
[0030] In one embodiment utilizing the Schrader-type valve, the
first 302 and second 402 volumes are filled by introducing
pressure, from a suitable gas pump or other source of pressurized
gas, into the gas fill valve 315 which includes or operates with,
or is replaced by, a Schrader -type valve 500 as shown in FIGS.
3-5. Referring to FIG. 3, the valve 500 is designed to fill both of
the first and second volumes with pressurized gas from the single
valve body 510. In FIG. 3, the valve is closed with no
communication of air therethrough.
[0031] In one aspect a valve stem 520 is connected through a valve
core 525 to a primary fill valve 530 such that axial movement of
the spring loaded valve stem 520 causes an opening of the primary
fill valve 530 and axial movement of a valve pusher stem 535.
Sufficient axial movement of the valve pusher stem 535 closes a gap
540 until the valve pusher stem 535 contacts the second chamber
fill valve stem 545. Following such closure of the gap 540, further
movement of the valve pusher stem 535 moves the second fill valve
stem 545 and correspondingly separates the second fill valve 550
from a valve seat. The design ensures that sufficient axial
movement of the valve stem 520 opens the primary fill valve 530 and
further movement of the valve stem subsequently opens the second
fill valve 550.
[0032] FIG. 4 illustrates a Schrader-type valve 500 with the valve
stem 520 depressed and primary fill valve 530 open. In this
position, pressurized air communicates through the valve 530 and to
exit 560 formed in valve body 510 which preferably leads to the
first gas volume 302. FIG. 5 illustrates the Schrader-type valve
500 with valve 530 open and gap 540 closed. Further, the second
fill valve stem 545 has been axially depressed to open secondary
fill valve 550. With the components of the Schrader-type valve in
the position shown in FIG. 5, the first and second volumes 302, 402
can be filled simultaneously. Gap 540 can be sized to determine
operative characteristics of the valve 500. For example, a gap of
0.050'' in one embodiment leaves a gap of sufficient width that
second chamber is not inadvertently filled along with the first
chamber.
[0033] The valve stem 520 may be moved either mechanically, by a
probe on a pressure fitting (not shown) of a pressurized gas
source, or solely by the introduction of pressurized gas into the
fill valve body 510 wherein the pressurized gas acts over the
surface area (i.e. piston area) of the primary fill valve 530. In
one embodiment, the dimension of the gap 540 is set such that
movement of the valve stem 520 and primary fill valve 530, caused
solely by the introduction of pressure, is not sufficient under
normal operating pressures to close the gap 540 between the valve
pusher stem 535 and the secondary fill valve stem 545.
Correspondingly, only the primary fill valve 530 is opened allowing
pressurized gas to be introduced into the first volume 302.
Movement sufficient to close the gap 540 and open secondary fill
valve 550 may be induced by a gas fill fitting (not shown)
connected to the fill gas pressure source and having a protrusion
or "stinger" in it that is dimensioned to move the valve stem a
sufficient distance to close the gap and open the secondary fill
valve 550. Alternatively, a fitting may be used without a stinger
and the valve stem 520 may be moved by gas pressure from the fill
gas pressure source. At certain lower velocities (based on lower
fill gas pressures or introduction rates) the movement of the valve
stem will be insufficient to open the secondary chamber fill valve
and only the first volume will be filled. Conversely the respective
porting of the valve assembly can be reversed (not shown) so that
initial movement of the valve stem opens the second fill valve and
further movement closes the gap and opens the primary fill
valve.
[0034] Optionally, a mechanical probe, attached to a pressure hose
fitting (not shown) for example, is used to move the valve stem
520. The length of the probe is sufficient to open the primary fill
valve 530, close the gap 540, cause movement of the valve pusher
stem 535 and secondary fill valve stem 545 and thereby open the
secondary fill valve 550. Correspondingly, pressurized gas flows
into the first volume 302 as previously described and also through
the open secondary fill valve 350, permitting flow into the second
volume 402.
[0035] In operation, the IFP gas pressure acts as the shock
absorber main spring in one embodiment tending to resist extension
of the "pull" shock, thereby providing a spring function for the
shock absorber 100, while the main cylinder air chamber 189 acts as
a shock absorber "negative spring" for the "pull" shock, tending to
resist compression thereof and, by user adjustment, aiding in
tailoring of gas spring curves by the user. The embodiment of FIG.
2 is designed whereby gas pressure in IFP cylinders 300, 400 will
bias the piston 180 towards the closed end of the main cylinder
178.
[0036] In one embodiment valve 200 permits operation of the shock
absorber of FIG. 2 in three different settings: full-travel,
half-travel and lock out. The system is intended to be
user-operable whereby the operator of the vehicle can shift the
valve 200 between the three functions. In the full-travel setting,
the oil is pushed by the piston 180 from the main cylinder 178 and
along a path that is shown on schematic FIG. 2 as 150. The fluid
extends through valve 200 to first IFP 300 and then, via a separate
and direct communication path 160, to IFP 400. This setting makes
both IFP gas chambers (and volumes) 302, 402 available as gas
springs in operation of the shock absorber. Further, the fluid is
transferred, during both extension and compression of the shock,
along a path that includes the damping fluid reservoirs in series.
Because of that, all of the reservoir damping liquid is available
during the full stroke of the shock absorber on every stroke.
Damping fluid communication directly between reservoirs ensures
that the reservoirs remain relatively equalized (or at a known and
predetermined operational differential) during operation and are
not subject to unplanned and detrimental fluid fill fluctuations.
Additionally, the sequential operation permits any metering of
fluid to be performed at a single location so that there is no need
(although optionally there may still be) to meter the fluid
separately in each IFP reservoir.
[0037] In a second compression setting (e.g. "half-travel mode"),
shown by path 151 of FIG. 2, oil flow to the first IFP chamber 300
is blocked at valve 200, causing all the pushed oil to flow into
the second IFP chamber 400 and therefore changing the effective
spring rate of the system (increasing the spring rate by decreasing
the available IFP gas volume but therefore decreasing the available
shock travel). The practical result of this half-travel setting is
a stiffer-acting shock absorber.
[0038] A third compression setting includes the full closure of
valve 200, effectively blocking oil flow to both IFP chambers 300,
400 and resulting in a shock absorber that is hydraulically locked
out. The third setting is especially useful to prevent operation of
the shock absorber in conditions when its operation is unnecessary
or unwanted by a user. The valve 200 may include a "blow off" or
pressure relief feature (optionally user adjustable) so that even
when "locked out" the shock absorber may move in response to
overpressure thereby avoiding damage to the shock or vehicle or
user.
[0039] In some embodiments, the three compression settings
described are selectable via user-accessible controls mounted
adjacent components of the shock absorber 100 or remotely (with
appropriate signal communication to the shock absorber such as
cable, wire, or wireless with servo motors). For example, in one
embodiment, a knob is adjustable between three positions
corresponding to the full-travel, half-travel and lock out
modes/positions described herein. In addition to the compression
settings described, the shock absorber of the embodiment described
also permits adjustment of operation in a rebound stroke (e.g.
adjustment of rebound damping). In the first and second settings,
the IFP gas pressure in 302, 402 pushes fluid out of the IFP
chambers 300, 400 and back into the main cylinder fluid chamber 188
as the piston 180 is moved in a rebound direction (shown as arrow
153). Each IFP has an externally adjustable valve 303, 403 that
allows the rebound flowing fluid to be metered, resulting in
different rebound fluid flow speeds. In one embodiment, the rebound
fluid is divided between the adjustable valves and factory set
shims (not shown). The valves 303, 403 permit a user to change the
operational aspects of the IFPs for proper suspension depending on,
among other things, road/trail conditions and loads. In each
setting, both IFP cylinder oil chambers 301, 401 flow their rebound
flow oil back to the main cylinder 178 through one common rebound
adjustor valve and flow path. For example, in full-travel mode, all
rebound fluid travels through and can be adjusted at valve 303 of
IFP 300. In half-travel mode, all fluid travels back towards the
main damper 125 via valve 403 of IFP 400.
[0040] Explaining the operation of some embodiments in more detail,
the movement of oil flow out of the main cylinder oil chamber 188
(compression flow shown as arrow 152) and oil back into the main
cylinder oil chamber 188 (rebound flow 153) will be elaborated upon
by example. In the first compression setting (full-travel mode) and
under compression flow, oil will flow into the first IFP 300.
Referring to FIG. 2 the full-travel mode flow path 150 comprises
nodes 1-5 of FIG. 2. The IFP oil chambers 301, 401 will communicate
with one another via fluid path 160 (nodes 4-5 including valve 322)
connecting them. This fluid path includes valve 322 that allows
flow to communicate in both directions between the IFP oil chambers
300, 400 when the shock is set in this first, full-travel
compression setting. The compression damping and the rebound
damping in the full-travel compression setting will each be unique
to this setting as the compression oil flow and rebound oil flow
are directed into and out of only one of the IFP chambers (IFP 300
via node 3) upstream of the fluid path 160 that permits both IFP
chambers to communicate. A rebound adjustor valve 303 provided in
path 3-2 controls and adjusts the rebound flow for this full-travel
setting. Shimmed or valved (shims being an example valve type)
compression and shimmed or valved rebound damping (not shown) are
also provided in path 3-2 specifically for the full-travel
setting.
[0041] When the shock is set to the half-travel setting,
compression flow is directed to second IFP 400 along path 151 as
shown in FIG. 2. Note that only the gas IFP 400 is compressed
because the IFP gas chambers are isolated from each other. Valve
322 in fluid path160 is closed in this setting in the direction of
IFP 400 to 300. A low speed rebound adjustor 403 is provided in
path 151 to control low speed rebound damping for this second
compression setting condition, and distinct shimmed compression
damping (not shown) and rebound damping are provided in path 151
specifically for this second, half-travel setting. Compression flow
is now directed only into IFP 400 and rebound flow is supplied only
from IFP 400. While the operation is described utilizing the IFPs
300, 400 in a particular manner it will be understood that the
chambers 300, 400 could be reversed in function and sequencing.
[0042] The described embodiment provides half or full-travel
operation and in each case, the rebound flow of fluid moves in a
single path and is metered at a single location, thus avoiding a
problem of prior art arrangements that leads one IFP crashing
because it receives less fluid than it expels due to unequal
metering.
[0043] FIGS. 6-9 are section views showing portions of a suspension
system that include some of the embodiments described herein. FIGS.
6-7, for example illustrate the flow of fluid within the shock in
full-travel mode whereby both of the IFPs 300, 400 are utilized in
the operation. FIG. 8 illustrates fluid flow in half-travel mode,
wherein only one of the IFPs (400) is utilized.
[0044] FIG. 6 shows the path of fluid between the main damper 125
and valve 200, which in the case of FIG. 6, is a spool valve (e.g.
in one embodiment a single valve member having multiple functions)
with a central shaft 205 for directing fluid in a variety of
different directions depending upon the axial location of the shaft
205 relative to the valve body and ports 220, 225 (FIG. 7)
connecting the valve to the IFPs 300, 400. In FIG. 6, a port 201 is
visible for providing fluid communication between the main damper
125 and valve 200. In each FIG. 6-9, fluid travel in a compression
mode of the damper is shown by a solid line/arrow 230 while fluid
travel in the rebound mode is shown by a dotted line/arrow 235. In
FIG. 6, solid line 230 illustrates the path of fluid during a
compression stroke as fluid leaves the damper 125 and moves into
the valve 200 from which it will travel to both IFPs 300, 400. FIG.
7 corresponds to FIG. 6 and shows fluid travel 230 from a port 220
in the spool valve 200 directly to a first IFP 300. A separate path
230a is utilized to carry fluid from IFP 300 to IFP 400 through
path 160 which in the embodiment of FIG. 7, is included in spool
valve 200. In the embodiment shown in the section views, valve 322,
controlling fluid flow in flow path 160 (FIG. 2) is also
incorporated into the spool valve 200 and the path of fluid through
that path is determined by a setting of the valve.
[0045] Following the path of the dotted line 235, it will be
appreciated that a portion of the fluid 235a traveling out of
(rebounding) IFP 300 can be metered by rebound needle valve 303
(FIG. 2) that is adjustable by a user via adjustment knob 255
accessible at an upper end of the IFP 300. Another portion of the
rebound fluid 235 is metered by shims (not shown).
[0046] FIG. 8 is a section view of the spool valve 200 and the IPOs
300, 400 and illustrates the half-travel mode when only a single
IFP 400 is utilized by the system. As shown in the Figure, fluid
travel between the valve and IFP 400 while IF 300 is not utilized.
In the half-travel mode, only the gas spring portion of one IFP 400
is used and the system therefore operates with stiffer
characteristics. Of note is the rebound path of the fluid (dotted
line 235) wherein a portion of the fluid travels through another
needle-type valve 403 (FIG. 2) that is adjustable via knob 256,
thereby permitting the rebound characteristics of the shock to be
user-adjusted in the half-travel mode.
[0047] FIG. 9 is another section view showing both IFPs and the
previously discussed fluid path between them (valve C) having a
one-way characteristic in which fluid may travel from IFP 300 to
IFP 400 in half-travel mode of operation. The feature permits fluid
in a non-used IFP to move to the other IFP so it can be utilized in
operation of the shock absorber.
[0048] The forgoing description and the Figures illustrate and
teach a shock absorber using one or more of multiple IFPs to
provide differing and adjustable amounts of a spring function when
the shock absorber operates. In a dual IFP reservoir embodiment one
mode provides that two IFPs are used in a sequential manner whereby
the fluid travels a path between them from one to the next. In a
rebound stroke of the shock absorber the fluid travels back along
the same or similar path, thereby providing a single point of
metering and avoiding some drawbacks of earlier designs, most
notably the possibility of an IFP locking up due to expulsion of
all of its fluid due to differing amounts of metering of the
rebound fluid. In one embodiment the flow path between reservoirs
includes a one way flowing check valve disposed to check fluid flow
entering the reservoir unused during half travel mode but allowing
fluid to flow from that cylinder to the half travel damping
reservoir. In that way, any fluid trapped in the unselected
cylinder while changing from full travel to half travel can freely
flow back to the main cylinder, or otherwise into the selected
damping circuit, as needed but no new fluid will be introduced into
the unselected reservoir during half travel operation. It is
noteworthy that several other flow options and combinations are
available in the shown embodiments.
[0049] While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
* * * * *