U.S. patent application number 14/625248 was filed with the patent office on 2016-08-18 for track-module bogie-suspension system.
This patent application is currently assigned to ATI, INC.. The applicant listed for this patent is ATI, Inc.. Invention is credited to Kenneth J. Juncker, Jamsheed Reshad, Timothy D. Stacy, Duane Tiede.
Application Number | 20160236733 14/625248 |
Document ID | / |
Family ID | 56620751 |
Filed Date | 2016-08-18 |
United States Patent
Application |
20160236733 |
Kind Code |
A1 |
Tiede; Duane ; et
al. |
August 18, 2016 |
TRACK-MODULE BOGIE-SUSPENSION SYSTEM
Abstract
Track-module bogie-suspension apparatus for attachment to a
track module having a frame, a drive wheel and an endless track.
The bogie-suspension apparatus comprises (a) a bogie assembly
having a bogie mount, at least one rotatable ground-engaging bogie
wheel thereon, and forward and rearward bogie-mount connections;
(b) first and second load- and ground-responsive suspension joints
spaced from one another in a forward/rearward direction; and (c)
leading and trailing suspension elements each having an upper end
and a lower end, the upper ends of the leading and trailing
suspension elements rotatably attached to the first and second
suspension joints, respectively, and the lower ends thereof
rotatably attached to the rearward and forward bogie-mount
connections, respectively.
Inventors: |
Tiede; Duane; (Naperville,
IL) ; Reshad; Jamsheed; (Newburgh, IN) ;
Stacy; Timothy D.; (Mt. Vernon, IN) ; Juncker;
Kenneth J.; (Mt. Vernon, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ATI, Inc. |
Mt. Vernon |
IN |
US |
|
|
Assignee: |
ATI, INC.
Mt. Vernon
IN
|
Family ID: |
56620751 |
Appl. No.: |
14/625248 |
Filed: |
February 18, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14625229 |
Feb 18, 2015 |
|
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14625248 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60G 2202/15 20130101;
B62D 55/112 20130101; B62D 55/104 20130101; B60G 11/27 20130101;
B62D 55/305 20130101; B62D 55/1125 20130101; B62D 55/0842 20130101;
B62D 55/14 20130101; B60G 5/01 20130101; B62D 55/10 20130101 |
International
Class: |
B62D 55/104 20060101
B62D055/104; B62D 55/10 20060101 B62D055/10; B60G 5/01 20060101
B60G005/01; B62D 55/14 20060101 B62D055/14; B60G 11/27 20060101
B60G011/27; B62D 55/112 20060101 B62D055/112; B62D 55/084 20060101
B62D055/084 |
Claims
1. (canceled)
2. The bogie-suspension apparatus of claim 33 further including a
third load- and ground-responsive suspension joint and wherein the
bogie assembly further includes a bogie-assembly arm rotatably
attached (a) at a bogie-assembly arm distal end to the third
suspension joint and (b) at a bogie-assembly arm proximal end to
the bogie mount.
3. The bogie-suspension apparatus of claim 2 further including
rotatable attachments of the leading and trailing suspension
elements at the first and second suspension joints, respectively,
which are configured to permit rotation having at least two
degrees-of-freedom, and the rearward and forward rotatable
bogie-mount connections are configured to permit rotation having at
least two degrees-of-freedom.
4. (canceled)
5. The bogie-suspension apparatus of claim 33 including at least
two leading bogie wheels and at least two trailing bogie wheels and
wherein the leading bogie axis rotates on a leading bogie roll axis
perpendicular thereto and the trailing bogie axis rotates on a
trailing bogie roll axis perpendicular thereto.
6. The bogie-suspension apparatus of claim 33 wherein the
bogie-mount forward and rearward portions are rotatably attached at
a third bogie-assembly axis.
7. The bogie-suspension apparatus of claim 33 wherein the bogie
mount further includes a bogie-mount middle portion having at least
one middle bogie wheel attached thereto at a middle bogie axis.
8. The bogie-suspension apparatus of claim 7 including at least two
leading bogie wheels, at least two trailing bogie wheels, and at
least two middle bogie wheels and wherein: the leading bogie axis
rotates on a leading bogie roll axis perpendicular thereto; the
middle bogie axis rotates on a middle bogie roll axis perpendicular
thereto; and the trailing bogie axis rotates on a trailing bogie
roll axis perpendicular thereto.
9. The bogie-suspension apparatus of claim 8 wherein the
bogie-mount forward and middle portions are rotatably attached at a
third bogie-assembly axis.
10. The bogie-suspension apparatus of claim 33 wherein the leading
and trailing suspension elements each include gas-filled components
to provide spring force.
11. The bogie-suspension apparatus of claim 10 wherein the leading
and trailing suspension elements each further include hydraulic
components.
12. The bogie-suspension apparatus of claim 11 wherein the leading
and trailing suspension elements are on a common hydraulic
circuit.
13. The bogie-suspension apparatus of claim 12 further including an
external accumulator hydraulically connected to the common
hydraulic circuit.
14. The bogie-suspension apparatus of claim 33 including plural
bogie wheels and wherein the bogie wheels have diameters which are
substantially the same as each other.
15. The bogie-suspension apparatus of claim 33 wherein the first
and second load- and ground-responsive suspension joints are
independently responsive to load and ground variations.
16. The bogie-suspension apparatus of claim 15 further including a
third load- and ground-responsive suspension joint and wherein the
bogie assembly further includes a bogie-assembly arm rotatably
attached (a) at a bogie-assembly arm distal end to the third
suspension joint and (b) at a bogie-assembly arm proximal end to
the bogie mount, the movement of the first and third suspension
joints being interdependent.
17. The bogie-suspension apparatus of claim 15 further including
rotatable attachments of the leading and trailing suspension
elements at the first and second suspension joints, respectively,
which are configured to permit rotation having at least two
degrees-of-freedom, and the rearward and forward rotatable
bogie-mount connections are configured to permit rotation having at
least two degrees-of-freedom.
18. (canceled)
19. The bogie-suspension apparatus of claim 15 including at least
two leading bogie wheels and at least two trailing bogie wheels and
wherein the leading bogie axis rotates on a leading bogie roll axis
perpendicular thereto and the trailing bogie axis rotates on a
trailing bogie roll axis perpendicular thereto.
20. The bogie-suspension apparatus of claim 15 wherein the
bogie-mount forward and rearward portions are rotatably attached at
a third bogie-assembly axis.
21. The bogie-suspension apparatus of claim 15 wherein the bogie
mount further includes a bogie-mount middle portion having at least
one middle bogie wheel attached thereto at a middle bogie axis.
22. The bogie-suspension apparatus of claim 21 including at least
two leading bogie wheels, at least two trailing bogie wheels, and
at least two middle bogie wheels and wherein: the leading bogie
axis rotates on a leading bogie roll axis perpendicular thereto;
the middle bogie axis rotates on a middle bogie roll axis
perpendicular thereto; and the trailing bogie axis rotates on a
trailing bogie roll axis perpendicular thereto.
23. The bogie-suspension apparatus of claim 22 wherein the
bogie-mount forward and middle portions are rotatably attached at a
third bogie-assembly axis.
24. The bogie-suspension apparatus of claim 33 wherein movements of
the first and second load- and ground-responsive suspension joints
are interdependent.
25. The bogie-suspension apparatus of claim 24 further including a
third load- and ground-responsive suspension joint and wherein the
bogie assembly further includes a bogie-assembly arm rotatably
attached (a) at a bogie-assembly arm distal end to the third
suspension joint and (b) at a bogie-assembly arm proximal end to
the bogie mount, the movement of the suspension joints being
interdependent.
26. The bogie-suspension apparatus of claim 24 further including
rotatable attachments of the leading and trailing suspension
elements at the first and second suspension joints, respectively,
which are configured to permit rotation having at least two
degrees-of-freedom, and the rearward and forward rotatable
bogie-mount connections are configured to permit rotation having at
least two degrees-of-freedom.
27. (canceled)
28. The bogie-suspension apparatus of claim 24 including at least
two leading bogie wheels and at least two trailing bogie wheels and
wherein the leading bogie axis rotates on a leading bogie roll axis
perpendicular thereto and the trailing bogie axis rotates on a
trailing bogie roll axis perpendicular thereto.
29. The bogie-suspension apparatus of claim 24 wherein the
bogie-mount forward and rearward portions are rotatably attached at
a third bogie-assembly axis.
30. The bogie-suspension apparatus of claim 24 wherein the bogie
mount further includes a bogie-mount middle portion having at least
one middle bogie wheel attached thereto at a middle bogie axis.
31. The bogie-suspension apparatus of claim 30 including at least
two leading bogie wheels, at least two trailing bogie wheels, and
at least two middle bogie wheels and wherein: the leading bogie
axis rotates on a leading bogie roll axis perpendicular thereto;
the middle bogie axis rotates on a middle bogie roll axis
perpendicular thereto; and the trailing bogie axis rotates on a
trailing bogie roll axis perpendicular thereto.
32. The bogie-suspension apparatus of claim 31 wherein the
bogie-mount forward and middle portions are rotatably attached at a
third bogie-assembly axis.
33. Track-module bogie-suspension apparatus for attachment to a
track module having a frame, a drive wheel and an endless track,
comprising: a bogie assembly having a bogie mount, at least one
leading bogie ground-engaging wheel and at least one trailing bogie
ground-engaging wheel thereon, and forward and rearward bogie-mount
connections, the bogie mount including: a bogie-mount forward
portion having the at least one leading bogie wheel rotatably
attached thereto at a leading bogie axis, the bogie-mount forward
portion including the forward bogie-mount connection; and a
bogie-mount rearward portion having the at least one trailing bogie
wheel rotatably attached thereto at a trailing bogie axis, the
bogie-mount rearward portion including the rearward bogie-mount
connection; first and second load- and ground-responsive suspension
joints spaced from one another in a forward/rearward direction; and
leading and trailing suspension elements each having an upper end
and a lower end, the upper ends of the leading and trailing
suspension elements rotatably attached to the first and second
suspension joints, respectively, and the lower ends thereof
rotatably attached to the rearward and forward bogie-mount
connections, respectively.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of application
Ser. No. 14/625,229 filed on Feb. 18, 2015, the contents of which
are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates generally to the field of vehicle
track-module systems of the type typically for use in place of
vehicle wheels and, more particularly, to track modules having
leading and trailing wheels and at least one load-supporting bogie
wheel between the leading and trailing wheels, all of which are
engaged by an endless track extending around the wheels to drive a
vehicle along the ground.
BACKGROUND OF THE INVENTION
[0003] Agricultural vehicles such as tractors, combines and the
like are commonly used in agricultural fields for a variety of
jobs, and construction vehicles and other large work vehicles are
used for many different jobs on a variety of ground surfaces.
Typically, these vehicles have large wheels with tires on which the
vehicles are supported on the ground. However, for improved
traction, vehicle track-module systems (or "track modules" or
track-module apparatus") are used in place of wheels with tires,
and such track-module systems provide a much larger ground-surface
engagement area supporting vehicle weight and tends to prevent
vehicles from becoming bogged down in mud or other soft ground
surfaces.
[0004] Among the challenges encountered in the use of vehicle
track-module apparatus is the need to distribute the load supported
by the track module among the various wheels. These loads are both
static and dynamic and may change during operation of the vehicle.
Loads change as the vehicle encounters uneven ground, as the
vehicle turns and as the slope of the ground being traversed
changes. Ideally, all wheels remain in contact with the ground
through the endless belt and share a portion of the load at all
times.
[0005] One track-module unit which is intended to distribute load
relatively evenly is disclosed in U.S. Pat. No. 7,628,235 (Satzler
et al.) owned by CLAAS Industrietechnik GmbH of Paderhorn, Germany.
A vehicle track roller unit is disclosed which has at least one
pivotable subframe and at least one further pivotable subframe, and
each of the subframes rotatably accommodates at least one land
wheel. At least one subframe is pivotably mounted on the vehicle,
and the at least one further subframe is pivotably mounted on the
at least one pivotable subframe.
[0006] Another vehicle track-module unit is disclosed in United
States Published Patent Application No. 2013/0154345 (Schultz et
al.) owned by CLAAS Selbstfahrende Erntemaschinen GmbH of
Harsewinkel, Germany. A vehicle track unit is disclosed which has a
plurality of supporting rollers arranged one behind the other in
the direction of travel of the vehicle and around which a belt is
wrapped. The rollers are adjusted by way of at least one actuator
between a first configuration, in which all supporting rollers are
loaded, and a second configuration, in which at least one outer
roller of the supporting rollers is relieved. An energy source
delivers drive energy required to adjust the configuration. An
energy accumulator is charged by the drive energy source and
connected to the actuator in order to provide the actuator with the
drive energy required to adjust the configuration.
[0007] CLAAS also has its Lexion Terra Trac product line which
includes configurations which are intended to address some of these
challenges. However, none of these prior art systems includes all
of the elements of the present invention and meets the needs as
outlined above.
OBJECTS OF THE INVENTION
[0008] It is an object of this invention to provide track-module
bogie-suspension apparatus which has high load-supporting
capability while maintaining lower contact forces on the ground by
providing lower loading per axle from more even load
distribution.
[0009] Another object of this inventive track-module
bogie-suspension apparatus is to minimize the unsprung mass of
track-module apparatus.
[0010] Another object of the inventive vehicle track-module
bogie-suspension apparatus is to provide track-module
bogie-suspension apparatus which shares load changes between
axles.
[0011] Yet another object of the inventive vehicle track-module
bogie-suspension apparatus is to provide track-module apparatus in
which the load distribution on the wheels is independent of
vertical load.
[0012] Still another object of the inventive vehicle track-module
bogie-suspension apparatus is to provide track-module apparatus
which has independent roll-mode movement for all bogie axes.
[0013] An additional object of this invention is to provide
track-module bogie-suspension apparatus which includes an
articulating bogie assembly and which includes independent
accommodation of bogie roll motion.
[0014] These and other objects of the invention will be apparent
from the following descriptions and from the drawings.
BRIEF SUMMARY OF THE INVENTION
[0015] This invention is a track-module bogie-suspension apparatus
for attachment to a track module which includes a frame, a drive
wheel and an endless track. The inventive bogie-suspension
apparatus comprises: (1) a bogie assembly having a bogie mount, at
least one rotatable ground-engaging bogie wheel thereon, and
forward and rearward bogie-mount connections; (2) first and second
load- and ground-responsive suspension joints spaced from one
another in a forward/rearward direction; and (3) leading and
trailing suspension elements each having an upper end and a lower
end, the upper ends of the leading and trailing suspension elements
rotatably attached to the first and second suspension joints,
respectively, and the lower ends thereof rotatably attached to the
rearward and forward bogie-mount connections, respectively.
[0016] The term "suspension elements" as used herein refers to
components in the suspension system which provide spring force
and/or damping in the system.
[0017] The term "ground-engaging" as used herein with respect to a
wheel means that the wheel bears on the ground through the endless
track that engages the wheel under normal operating conditions.
[0018] The term "bogie wheel(s)" as used herein refers to one or
more wheels providing support for a vehicle in a middle
ground-engaging region of a track module, with other
ground-engaging support being provided rearward and/or forward of
the bogie wheels(s).
[0019] The term "therebetween" when referring to the position of
ground-engaging bogie wheels means that the bogie wheels are
positioned behind the leading ground-engaging wheel(s) and ahead of
the trailing ground-engaging wheel(s) along the direction of
travel. The term "idler" as used herein refers to wheel which is
not a driven wheel but turn only by virtue of its engagement with
the endless track.
[0020] The term "load- and ground-responsive" as used herein with
respect to suspension joints means that the above-ground positions
of such joints are variable, including with respect to the frame,
and depend on the contour of the ground under the track and on the
total loading on the track module, however caused.
[0021] The term "interdependent" as used herein in the describing
the movements of a set of load- and ground-responsive suspension
joints refers to the fact that the movement in one such joint
causes movements in all joints in the set. This interdependence may
be brought about by having rigid structures which connect such
interdependent suspension joints. The movements of such
interdependent joints are not necessarily in the same direction nor
of the same magnitude; these relationships depend on the structural
configurations connecting such suspension joints.
[0022] Certain preferred embodiments of the inventive
bogie-suspension apparatus of claim 1 further includes a third
load- and ground-responsive suspension joint, and the bogie
assembly further includes a bogie-assembly arm which is rotatably
attached (a) at a bogie-assembly arm distal end to the third
suspension joint and (b) at a bogie-assembly arm proximal end to
the bogie mount. In some of these embodiments, the rotatable
attachments of the leading and trailing suspension elements at the
first and second suspension joints, respectively, are configured to
permit rotation having at least two degrees-of-freedom, and the
rearward and forward rotatable bogie-mount connections are
configured to permit rotation having at least two
degrees-of-freedom.
[0023] In some preferred embodiments of the bogie-suspension
apparatus, the at least one bogie wheel includes at least one
leading bogie wheel and at least one trailing bogie wheel, and the
bogie mount includes (a) a bogie-mount forward portion which has
the at least one leading bogie wheel rotatably attached thereto at
a leading bogie axis, the bogie-mount forward portion including the
forward bogie-mount connection, and (b) a bogie-mount rearward
portion which has the at least one trailing bogie wheel rotatably
attached thereto at a trailing bogie axis, the bogie-mount rearward
portion including the rearward bogie-mount connection.
[0024] Certain preferred embodiments include at least two leading
bogie wheels and at least two trailing bogie wheels, the leading
bogie axis rotates on a leading bogie roll axis perpendicular
thereto, and the trailing bogie axis rotates on a trailing bogie
roll axis perpendicular thereto.
[0025] In some other embodiments, the bogie-mount forward and
rearward portions are rotatably attached at a third bogie-assembly
axis.
[0026] In some preferred embodiments, the bogie mount further
includes a bogie-mount middle portion which has at least one middle
bogie wheel attached thereto at a middle bogie axis. Some of these
embodiments include at least two leading bogie wheels, at least two
trailing bogie wheels, and at least two middle bogie wheels. In
these embodiments, (a) the leading bogie axis rotates on a leading
bogie roll axis perpendicular thereto, (b) the middle bogie axis
rotates on a middle bogie roll axis perpendicular thereto, and (c)
the trailing bogie axis rotates on a trailing bogie roll axis
perpendicular thereto. Further, in some of these embodiments, the
bogie-mount forward and middle portions are rotatably attached at a
third bogie-assembly axis.
[0027] In some highly-preferred embodiments of the inventive
bogie-suspension apparatus, the leading and trailing suspension
elements each include gas-filled components to provide spring
force. In some of these embodiments, the leading and trailing
suspension elements each further include hydraulic components, and
in some of these embodiments the leading and trailing suspension
elements are on a common hydraulic circuit. Also, some of these
embodiments include an external accumulator hydraulically which is
connected to the common hydraulic circuit.
[0028] In some embodiments which have plural bogie wheels, the
bogie wheels have diameters which are substantially the same as
each other.
[0029] In some highly-preferred embodiments, the first and second
load- and ground-responsive suspension joints are independently
responsive to load and ground variations. In some other
embodiments, the movements of the first and second load- and
ground-responsive suspension joints are interdependent.
[0030] Some highly-preferred embodiments also include a third load-
and ground-responsive suspension joint, and the bogie assembly
further includes a bogie-assembly arm rotatably attached (a) at a
bogie-assembly arm distal end to the third suspension joint and (b)
at a bogie-assembly arm proximal end to the bogie mount. In such
embodiments, the movements of the suspension joints are
interdependent.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1A is a perspective drawing of an embodiment of the
vehicle track-module apparatus of this invention.
[0032] FIG. 1B is a perspective drawing of the embodiment of FIG.
1A as viewed from the side opposite that shown in FIG. 1A.
[0033] FIG. 2 is a perspective drawing of portions of the
embodiment of the vehicle track-module apparatus of FIGS. 1A and
1B, illustrating the suspension linkage components without the
drive wheel, endless polymeric track, wheels, frame and suspension
elements.
[0034] FIG. 3 is an exploded perspective drawing of the embodiment
of FIGS. 1A and 1B.
[0035] FIG. 4 is a side-elevation drawing of the embodiment of
FIGS. 1A and 1B with the near set of idler and bogie wheels removed
to show the linkages.
[0036] FIG. 5 is side-elevation drawing of portions of the
embodiment of the vehicle track-module apparatus of FIGS. 1A and
1B, showing the suspension linkage components without the drive
wheel and the endless track and wheels.
[0037] FIG. 6A is a perspective drawing of the bogie mount portions
of the bogie assembly of the vehicle track-module apparatus of
FIGS. 1A and 1B.
[0038] FIG. 6B is a perspective drawing of the bogie mount of FIG.
6A showing the bogie-mount forward portion rotated with respect to
the bogie-mount rearward portion around the third bogie-assembly
axis.
[0039] FIGS. 7A-7F are side-elevation drawings of the embodiment of
FIGS. 1A and 1B illustrating the movement of the vehicle
track-module apparatus as it traverses over a small bump along its
path of travel. FIG. 7A shows the track-module apparatus just prior
to encountering the bump.
[0040] FIG. 7B shows the track-module apparatus with its leading
idler wheels over the bump.
[0041] FIG. 7C shows the track-module apparatus with its leading
bogie wheels over the bump.
[0042] FIG. 7D shows the track-module apparatus with its middle
bogie wheels over the bump.
[0043] FIG. 7E shows the track-module apparatus with its trailing
bogie wheels over the bump.
[0044] FIG. 7F shows the track-module apparatus with its trailing
idler wheels over the bump.
[0045] FIG. 8A is a side-elevation drawing of the embodiment of
FIGS. 1A and 1B illustrating the movement of the vehicle
track-module apparatus as it traverses an uphill path.
[0046] FIG. 8B is a side-elevation drawing of the embodiment of
FIGS. 1A and 1B illustrating the movement of the vehicle
track-module apparatus as it traverses a downhill path.
[0047] FIG. 9 is a schematic drawing of the leading and trailing
suspension elements in a hydraulic circuit.
[0048] FIG. 10 is a schematic diagram of the embodiment of FIGS. 1A
and 1B illustrating the supported load FL and the five resulting
wheel loads F1 through F5.
[0049] FIG. 11 is a side-elevation drawing (similar to FIG. 4) of a
first alternative embodiment of the vehicle track-module apparatus
of this invention. Such embodiment is similar to the embodiment of
FIG. 4 but includes only leading and trailing bogie wheels with
corresponding modifications to the components used in the
suspension system.
[0050] FIG. 12 is a side-elevation drawing (similar to FIG. 4) of a
second alternative embodiment of the vehicle track-module apparatus
of this invention. Such embodiment is similar to the embodiment of
FIG. 11 but does not include a tensioning element and the
leading-idler assembly includes only the leading idler wheel.
[0051] FIG. 13 is a side-elevation drawing (similar to FIG. 4) of a
third alternative embodiment of the vehicle track-module apparatus
of this invention. Such embodiment is similar to the embodiment of
FIG. 4 but does not include a tensioning element and the
leading-idler assembly includes only the leading idler wheel.
[0052] FIG. 14 is a side-elevation drawing (similar to FIG. 4) of a
fourth alternative embodiment of the vehicle track-module apparatus
of this invention. Such embodiment is similar to the embodiment of
FIG. 13 but does not include the third bogie-assembly axis.
[0053] FIG. 15A is side-elevation drawing of portions of the
embodiment of the vehicle track-module apparatus of FIG. 1 to
illustrate the detail of an end of the tensioning element.
[0054] FIG. 15B is a sectional view of FIG. 15A.
[0055] FIG. 15C is an enlargement of a portion of FIG. 15B
particularly showing an end of the tensioning element.
[0056] FIG. 16 is a table of reference numbers for the components
and other things illustrated in FIGS. 1A-15C and 17A-20 and for the
forces represented in the drawings.
[0057] FIG. 17A is a table of dimensions for an exemplary
track-module apparatus.
[0058] FIG. 17B is a set of five tables illustrating five different
sets of loads on the exemplary apparatus of FIG. 17A and the five
resulting load distributions.
[0059] FIG. 18 is perspective drawing of a fifth alternative
track-module embodiment that includes a bogie-suspension apparatus
in which the movements of the first and second load- and
ground-responsive suspension joints are interdependent.
[0060] FIG. 19 is a side elevation drawing of the embodiment of
FIG. 18.
DETAILED DESCRIPTIONS OF PREFERRED EMBODIMENTS
[0061] FIG. 1A is a perspective drawing of an embodiment 10 of the
vehicle track-module apparatus of this invention. (As referred to
herein, an embodiment of a track-module apparatus and the
track-module apparatus itself may be referred to using the same
reference number. Thus, for example, "embodiment 10" and
"track-module apparatus 10" refer to the same apparatus.)
Embodiment 10 includes a module frame 12, a drive wheel 14 which is
rotatable with respect to frame 12, the drive wheel having a drive
wheel axis 16, ground-engaging leading wheels 18 and
ground-engaging trailing wheels 20 and ground-engaging bogie wheels
56, 60 and 64, and an endless track 22 which extends around wheels
14, 18, 20, 56, 60 and 64 and is driven by its engagement with
drive wheel 14.
[0062] FIG. 1B is a perspective drawing of track-module apparatus
10 of FIG. 1A as viewed from the side opposite that shown in FIG.
1A. Referring to FIG. 1B, track-module apparatus 10 includes a
vehicle connection 11 at which track-module apparatus 10 is
attached to a vehicle and a drive gearbox 14g which receives power
from the vehicle through a drive power input shaft 14p.
[0063] In embodiment 10, leading wheels 18 are leading idler wheels
18, and trailing wheels 20 are trailing idler wheels 20. In some
embodiments of the track-module apparatus disclosed herein, it is
contemplated that a leading or trailing wheel may also function as
the drive wheel. Also in embodiment 10, endless track 22 is an
endless polymeric track 22. It is contemplated that endless track
22 may be constructed of a wide variety of materials and structures
including metallic components such as are presently known in some
tracked vehicles. The specific properties and materials of the
endless track are not central to the concepts of the track-module
configuration.
[0064] Bogie wheels 56 are leading bogie wheels, bogie wheels 60
are trailing bogie wheels, and bogie wheels 64 are middle bogie
wheels. Bogie wheels 56, 60 and 64 are part of a bogie assembly 46.
Embodiment 10 also includes a leading suspension arm 24, a trailing
suspension arm 34, a leading suspension element 68, a trailing
suspension element 70, and a tensioning element 106. Leading
suspension element 68 includes upper end 68U and a lower end 68L,
and trailing suspension element 70 includes an upper end 70U and a
lower end 70L. The upper-end and lower-end nomenclature and
reference number usage is specifically shown in FIGS. 4 and 18-19
and discussed with respect to the embodiment of FIGS. 18-19.
[0065] The direction of forward travel of the track module of
embodiment 10 (and other similar embodiments presented herein) is
defined by leading idler wheels 18 being ahead of trailing idler
wheels 20. FIG. 4 includes an arrow 122 indicating the direction of
travel applicable to all embodiments as defined by the leading and
trailing components of the embodiments.
[0066] FIGS. 2 through 6B illustrate track-module apparatus 10 and
various partial assemblies thereof in several views in order to
show more clearly the various aspects of track-module apparatus 10.
FIG. 2 is a perspective drawing of portions of track-module
apparatus 10, illustrating the several suspension linkage
components without drive wheel 14, track 22, leading idler wheels
18, trailing idler wheels 20, leading bogie wheels 56, trailing
bogie wheels 60, middle bogie wheels 64, frame 12, leading
suspension element 68, trailing suspension element 70, and
tensioning element 106. FIG. 3 is an exploded perspective drawing
of track-module apparatus 10.
[0067] FIG. 4 is a side-elevation drawing of track-module apparatus
10 with the near (in the drawing) set of idler wheels 18 and 20 and
bogie wheels 56, 60 and 64 removed to show the various elements of
embodiment 10 more clearly.
[0068] FIG. 5 is side-elevation drawing of portions of vehicle
track-module apparatus 10. Similar to FIG. 2, FIG. 5 illustrates
various components of apparatus 10 with some components not shown
to increase the visibility of other components.
[0069] FIGS. 6A and 6B are perspective drawings of the bogie mount
portions of bogie assembly 46 of vehicle track-module apparatus 10
without bogie wheels 56, 60 and 64. FIG. 6A illustrates bogie mount
48 oriented as if apparatus 10 were on a flat portion of the
ground. FIG. 6B illustrates bogie mount 48 as if apparatus 10 were
on uneven ground to illustrate some of the degrees-of-freedom
available in the configuration of bogie mount 48 of bogie assembly
46. Further description is presented below in this document.
[0070] The following description of track-module apparatus 10
refers to FIGS. 1A-6B together. Note that in all of the drawings, a
"+" symbol is used to indicate an axis of rotation. In general, as
used herein, the term "axis" pertains to a pivot joint which
includes the necessary bearing structure and other components to
permit rotation about such axis. As an example, drive wheel axis 16
about which drive wheel 14 rotates is indicated in FIG. 4 by a "+"
symbol. Portions of a bearing structure (not shown) which are
needed for drive wheel 14 to rotate around axis 16 are assumed to
be part of embodiment 10. In six instances within embodiment 10,
the "+" symbol indicates a pivot point which may provide more than
one degree-of-freedom of relative motion. This is indicated by (a)
the name including the word "pivot" rather than "axis" and (b) the
relevant reference number ending with the letter "p". These
instances are 82p, 84p, 86p, 88p, 112p and 116p. As described later
in this document, such higher number of degrees-of-freedom of
relative motion may be provided by the use of spherical bearings.
It should be understood that it is intended that in some
embodiments, such "pivots" may also simply be axes configured for
single degree-of-freedom rotation. The use of the term "pivot" is
not intended to limit the scope of the present invention to
multiple degrees-of-freedom motion at such locations within
embodiments having such pivots.
[0071] Leading suspension arm 24 is rotatably attached to frame 12
at a leading arm axis 26 and extends forward to a leading-arm
distal end 28 at which a leading-wheel assembly 30 is rotatably
attached. In apparatus 10, leading-wheel assembly 30 is also called
leading-idler assembly 30 since in apparatus 10, leading wheel 18
is leading idler wheel 18. Leading suspension arm 24 extends
rearwardly to a rearward suspension end 32. In similar fashion,
trailing suspension arm 34 is rotatably attached to frame 12 at a
trailing arm axis 36 and extends rearward to a trailing-arm distal
end 38 at which a trailing-wheel assembly 42 is attached. In
apparatus 10, trailing-wheel assembly 42 is also called
trailing-idler assembly 42 since in apparatus 10, trailing wheel 20
is trailing idler wheel 20.
[0072] In embodiment 10, trailing-idler assembly 42 primarily
comprises trailing idler wheels 20 which are rotatably attached at
a trailing-idler axis 118. Trailing suspension arm 34 extends
forwardly to a forward suspension end 40. In embodiment 10, leading
arm axis and trailing arm axis 36 are coincident and together form
suspension-arm axis 44. Such coincidence is not intended to be
limiting; other configurations of the track-module apparatus in
which leading arm axis 26 and trailing arm axis 36 are not
coincident are contemplated.
[0073] Suspension-arm axis 44 of embodiment 10 is shown as being
rearward of and below drive wheel axis 16 as defined by
direction-of-travel arrow 122 in FIG. 4. Such relative positioning
with respect to drive wheel axis 16 is not intended to be limiting;
other relative positions of leading arm axis 26 and trailing arm
axis 36 are contemplated for such track-module apparatus.
[0074] Bogie assembly 46 includes two leading bogie wheels 56, two
middle bogie wheels 64, and two trailing bogie wheels 60. Bogie
assembly 46 also includes a bogie mount 48 which includes
bogie-mount forward portion 50, a bogie-mount middle portion 54, a
bogie-mount rearward portion 52, and a bogie-mount arm 102. Leading
bogie wheels 56 are rotatable with respect to bogie-mount forward
portion 50 around a leading bogie axis 58. In addition, leading
bogie axis 58 rotates through a limited range of angles about a
leading bogie roll axis 96 which is perpendicular to leading bogie
axis 58.
[0075] In a similar fashion, such relative rotational movement is
also provided for middle bogie wheels 64 and trailing bogie wheels
60. Middle bogie wheels 64 are rotatable with respect to
bogie-mount middle portion 54 around a middle bogie axis 66. Middle
bogie axis 66 rotates through a limited range of angles about a
middle bogie roll axis 100 which is perpendicular to middle bogie
axis 66. Trailing bogie wheels 60 are rotatable with respect to
bogie-mount rearward portion 52 around a trailing bogie axis 62.
Trailing bogie axis 62 rotates through a limited range of angles
about a trailing bogie roll axis 98 which is perpendicular to
trailing bogie axis 62.
[0076] Bogie mount 48 also includes bearings 96b, 100b and 98b,
configured as follows: (1) bearing 96b at leading bogie roll axis
96; (2) bearing 100b at middle bogie roll axis 100; and (3) bearing
98b at trailing bogie roll axis 98. Bogie assembly 46 also includes
a leading bogie axle assembly 96a to which leading bogie wheels 56
are rotatably attached, a middle bogie axle assembly 100a to which
middle bogie wheels 64 are rotatably attached, and a trailing bogie
axle assembly 98a to which trailing bogie wheels 60 are rotatably
attached. Bearings 96b, 100b and 98b are configured to permit bogie
axle assemblies 96a, 100a and 98a, respectively, to rotate on such
bearings around leading bogie roll axis 96, middle bogie roll axis
100 and trailing bogie roll axis 98, respectively. Leading bogie
roll axis 96 and trailing bogie roll axis 98 are indicated at
respective ends of bogie mount 48 in FIGS. 6A and 6B. Also in FIGS.
6A and 6B, middle bogie roll axis 100 is indicated by dotted lines
at middle bogie roll axis bearing 100b but should be understood to
be located internally in the center of bearing 100b, parallel to
such dotted lines and not on the surface of bearing 100b.
[0077] Bogie mount 48 of bogie assembly 46 is rotatably attached at
a first bogie-assembly axis 78 to leading suspension arm 24 at a
location along arm 24 between leading arm axis 26 and leading-arm
distal end 28 by a bogie-assembly arm 72 at a bogie-assembly arm
distal end 74. (First bogie-assembly axis 78 is also herein
referred to as third load- and ground-responsive suspension joint
78.) Bogie-assembly arm 72 also includes a bogie-assembly arm
proximal end 76 which is rotatably attached to a bogie-mount arm
102 of bogie mount 48 at a second-bogie-assembly axis 80.
[0078] Bogie mount 48 of bogie assembly 46 is also attached to
leading suspension arm 24 and trailing suspension arm 34 by
suspension elements 68 and 70. Leading suspension element 68 is
rotatably attached to rearward suspension end 32 of leading
suspension arm 24 at a leading suspension-element pivot 82p and is
rotatably attached to bogie-mount rearward portion 52 at a first
bogie-assembly pivot 84p at a rearward bogie-mount connection 92.
Trailing suspension element 70 is rotatably attached to forward
suspension end 40 of trailing suspension arm 34 at trailing
suspension-element pivot 86p and is rotatably attached to
bogie-mount forward portion 50 at a second bogie-assembly pivot 88p
at a forward bogie-mount connection 94.
[0079] Leading suspension-element pivot 82p is sometimes herein
referred to as first load- and ground-responsive suspension joint
82p, and trailing suspension-element pivot 86p is sometimes herein
referred to as second load- and ground-responsive suspension joint
86p. The term "load- and ground-responsive suspension joint" is
sometimes shortened to "suspension joint."
[0080] Within bogie mount 48 of bogie assembly 46 in track-module
apparatus 10, bogie-mount forward portion 50 and bogie-mount middle
portion 54 are rotatably attached at a third bogie-assembly axis
90.
[0081] Embodiment 10 includes a tensioning element 106 which
provides attachment between leading suspension arm 24 and
leading-idler assembly 30. Leading-idler assembly 30 includes
leading idler wheels 18 and a leading-idler axis 104 about which
leading idler wheels 18 rotate. Leading-idler assembly 30 also
includes a wheel linkage 120 at leading-idler axis 104; in
apparatus 10, wheel linkage 120 is idler linkage 120. Leading-arm
distal end 28 is rotatably attached to idler linkage 120 at an
idler offset axis 114 which is offset from leading-idler axis
104.
[0082] A tensioning-element first end 108 of tensioning element 106
is rotatably attached to leading suspension arm 24 at a proximal
tensioning pivot 112p at forward suspension end 40 between
leading-arm distal end 28 and suspension-arm axis 44. A
tensioning-element second end 110 is rotatably attached to
leading-idler assembly 30 at a distal tensioning pivot 116p offset
from leading-idler axis 104. Idler offset axis 114 is parallel to
leading-idler axis 104 and angularly displaced therearound such
that idler linkage 120 is a class 2 lever with idler offset axis
114 being the fulcrum thereof. Tension forces on track 22 are
provided through idler wheels 18 by tensioning element 106 through
the class 2 lever action of idler linkage 120 acted on by
tensioning element 106.
[0083] Suspension elements 68 and 70 and tensioning element 106 may
provide both spring and damping forces. In some embodiments, such
elements may be gas-filled and include a liquid-filled cavity to
provide both types of forces for the suspension system. Such
elements are well-known to those skilled in the art of vehicle
suspension. Further description of suspension elements 68 and 70 is
provided in the description of FIG. 9.
[0084] FIGS. 7A through 8B illustrate the kinematics of
track-module apparatus 10 under various operating conditions. Each
such drawing is a side-elevation illustration of apparatus 10 under
representative conditions to show the relative movement of the
components of apparatus 10 under such conditions. FIGS. 7A-7F
illustrate the movement of vehicle track-module apparatus 10 as it
traverses over a small bump 126 on the ground 124 along its path of
travel. FIG. 7A shows track-module apparatus 10 just prior to
encountering bump 126. FIG. 7B shows apparatus 10 with its leading
idler wheels 18 over bump 126. FIG. 7C shows apparatus 10 with
leading bogie wheels 18 over bump 126. FIG. 7D shows apparatus 10
with middle bogie wheels 64 over bump 126. FIG. 7E shows apparatus
10 with trailing bogie wheels 60 over bump 126. FIG. 7F shows
apparatus 10 with trailing idler wheels 20 over bump 126.
[0085] FIG. 8A is a side-elevation drawing of track-module
apparatus 10 illustrating apparatus 10 as it traverses an uphill
portion 128 of ground 124. Similarly, FIG. 8B is a side-elevation
drawing of apparatus 10 illustrating apparatus 10 as it traverses a
downhill portion 130 of ground 124. Each of the drawings of FIGS.
7A through 8B illustrate idler wheels 18 and 20 and bogie wheels
56, 60 and 64 all in contact with ground 124 in order to support
some portion of the loads on apparatus 10.
[0086] FIG. 9 is a schematic drawing of leading suspension element
68 and trailing suspension element 70 in a hydraulic circuit 134.
Suspension elements 68 and 70 each include cylinders hydraulic 136
containing hydraulic fluid 144 and gas-filled cylinders 138
containing gas 146 separated by pistons 140. Hydraulic cylinders
136 and gas-filled cylinders 138 are movably sealed for relative
movement by seals 142, and gas-filled cylinders 138 and pistons 140
are movably sealed for relative movement by another set of seals
142 such that the volumes of hydraulic fluid 144 and gas 146 may
both change under loads which are applied across suspension
elements 68 and 70. In such components, gas 146 is typically
nitrogen but other gases may be used.
[0087] Hydraulic cylinders 136 are interconnected by a hydraulic
conduit 148 placing suspension elements 68 and 70 in a common
hydraulic circuit such that the pressures in suspension elements 68
and 70 are equal. Gas 146 in gas-filled cylinders 138 enables
suspension elements 68 and 70 to provide spring forces to the
suspension system of apparatus 10 while hydraulic fluid 144 flowing
through hydraulic conduit 148 enables suspension elements 68 and 70
to provide damping forces to the suspension system of apparatus
10.
[0088] Hydraulic circuit 134 also includes an external accumulator
150 connected to hydraulic conduit 148 by an accumulator conduit
156. Accumulator 150 includes both hydraulic fluid 144 and gas 146
in sealed separation from one another by an accumulator piston 152
movably sealed within accumulator 150 by accumulator seal 154. Gas
146 within accumulator 150 provides additional spring force to the
suspension system of apparatus 10 while hydraulic fluid 144 flowing
through accumulator conduit 156 and hydraulic conduit 148 provides
additional damping force to suspension system of apparatus 10.
[0089] Suspension elements 68 and 70 and tensioning element 106 may
provide suspension forces which are variable. For example, the
damping forces may depend on the direction of the movement
(extension or contraction) of the element in order to provide a
specific desired suspension performance.
[0090] The operation of the components of hydraulic circuit 134 are
well-known to those skilled in mechanical systems. FIG. 9 is
intended only to be schematic. For example, the functions of
accumulator piston 152 and accumulator seal 154 may be provided by
a membrane, a bladder or other similar component. In similar
fashion, the components of suspension elements 68 and 70 may also
be different from those described above while providing similar
operation of suspension elements 68 and 70.
[0091] FIG. 10 is a schematic diagram of the embodiment of FIGS. 1A
and 1B, illustrating a supported load FL and a set of five
resulting wheel loads F1 through F5. The load on leading wheels 18
is referred to as F1; the load on leading bogie wheels 56 is
referred to as F2; the load on middle bogie wheels 64 is referred
to as F3; the load on trailing bogie wheels 60 is referred to as
F4; and the load on trailing wheels 20 is referred to as F5. Since
all of supported load FL acts on suspension-arm axis 44, FIG. 10
shows FL at such location in the schematic diagram of FIG. 10.
[0092] The load FL supported by track-module apparatus 10 may have
both vertical and horizontal components depending on the specific
operational situation. These include at least the following: (a)
the portion of the vehicle weight supported by apparatus 10; (b)
pulling forces when the vehicle is pulling a load; and (c) braking
forces which in an emergency braking situation may be quite high.
Also, of course, each of the resulting forces F1 through F5 may
also have both vertical and horizontal components, and all of these
forces vary with the slope of the ground being traversed.
[0093] FIGS. 11 through 14 are side-elevation drawings (similar to
FIG. 4) illustrating several alternative embodiments 10a through
10d, respectively, of the vehicle track-module apparatus. In each
of FIGS. 11-14, the same reference numbers are used for components
similar to those of track-module apparatus 10.
[0094] FIG. 11 is a side-elevation drawing (similar to FIG. 4) of a
first alternative embodiment 10a of the vehicle track-module
apparatus. Embodiment 10a is similar to embodiment 10 except that
middle bogie wheels 64 have been eliminated with corresponding
changes in other components to accommodate such modification. A
track module similar to first alternative embodiment 10a may be
used to reduce complexity and cost when compared to embodiment 10
and/or may be used when the distance between the leading and
trailing wheels needs to be shorter than is provided by embodiment
10.
[0095] FIG. 12 is a side-elevation drawing (similar to FIG. 4) of a
second alternative embodiment 10b of the vehicle track-module
apparatus. Embodiment 10b is similar to first alternative
embodiment 10a except that tensioning element 106 has been
eliminated and leading-idler assembly 30 primarily includes only
leading idler wheels 18. A track module similar to second
alternative embodiment 10b may be used to reduce complexity and
cost when compared to embodiment 10. Similar to first embodiment
10a, second embodiment 10b may also provide a shorter distance
between the leading and trailing wheels if such a configuration is
desirable.
[0096] FIG. 13 is a side-elevation drawing (similar to FIG. 4) of a
third alternative embodiment 10c of the vehicle track-module
apparatus. Embodiment 10c is similar to embodiment 10 except that
tensioning element 106 has been eliminated and leading-idler
assembly 30 primarily includes only leading idler wheels 18. A
track module similar to third alternative embodiment 10c may be
used to reduce complexity and cost when compared to embodiment
10.
[0097] FIG. 14 is a side-elevation drawing (similar to FIG. 4) of a
fourth alternative embodiment 10d of the vehicle track-module
apparatus. Embodiment 10d is similar to third alternative
embodiment 10c except that third bogie-assembly axis 90 has been
eliminated with corresponding changes in other components to
accommodate such modification. A track module similar to fourth
alternative embodiment 10d may be used to reduce complexity and
cost when compared to embodiment 10. In the case of fourth
embodiment 10d, a degree-of-freedom within bogie assembly 46 has
been removed; under certain operational conditions such as travel
mainly on generally even terrain, this reduction in compliance may
be acceptable.
[0098] FIG. 15A is side-elevation drawing of portions of vehicle
track-module apparatus 10 to illustrate the detail of
tensioning-element first end 108 of tensioning element 106. FIG.
15B is a sectional view (section A-A) as indicated in FIG. 15A.
Section A-A passes through proximal tensioning pivot 112p at the
rotatable attachment between tensioning element 106 and leading
suspension arm 24.
[0099] FIG. 15C is a further enlargement of a portion of FIG. 15B
to show even more detail of proximal tensioning pivot 112p. As
described above, certain pivot points within apparatus 10 involve
structures which provide more than one degree-of-freedom of
rotation. In the naming convention used herein, the word "pivot" is
used for such more than one degree-of-freedom connections. Within
apparatus 10, these include 82p, 84p, 86p, 88p, 112p and 116p, and
FIGS. 15A-15C are used to illustrate one such pivot. In embodiment
10, all such pivots are spherical bearings as is shown for pivot
112p.
[0100] Referring to FIG. 15C, proximal tensioning pivot 112p
includes a spherical bearing which includes a ball 112b which
rotates in a socket 112s on leading suspension arm 24. A mechanical
connector 112c holds ball 112c in socket 112s.
[0101] By using the inventive structure of the various embodiments
of track-module apparatus disclosed herein and by selecting the
dimensions of the various components, a track-module designer is
able to set the load distribution on the ground-engaging wheels to
meet the requirements of a particular vehicle application. For
example, it may be desirable to have the leading or trailing wheels
take somewhat different percentages of the load on the vehicle. And
often it is desirable, when the apparatus has more than one
bogie-wheel axle, to have each of the bogie-wheel axles support
substantially the same vehicle load. A set of linkage dimensions
can be chosen to distribute the load supported by the bogies as
desired.
[0102] Kinematic analysis methods well-known to those skilled in
the art of mechanical systems can be used to evaluate the
load-distribution performance of a specific set of linkage
dimensions in apparatus 10. In the example described below and in
FIGS. 17A and 17B, such analysis was used to compute the load
distribution under a set of different load conditions. Referring to
the schematic diagram of FIG. 10, the dimensions are represented by
the following notation. A horizontal dimension includes the letter
"H" followed by two reference numbers separated by a colon. Thus,
H44:118 is the horizontal distance from suspension axis 44 to
trailing-idler axis 118. The letter "V" indicates a vertical
dimension, and the letter "D" a diameter. FIG. 17A summarizes a set
of dimensions for a representative configuration of track-module
apparatus 10 with suspension elements 68 and 70 in common hydraulic
circuit 134.
[0103] FIG. 17B summarizes the results of analysis of the
representative example of FIG. 17A. As can be seen, in this
example, the loads F2, F3 and F4 on bogie wheels 56, 64 and 60,
respectively, are and remain evenly distributed among the bogie
wheels, and the addition of various portions of the total loading
from vehicle weight, track tension, braking and pull cause very
modest changes to the load distribution percentages.
[0104] The power source for the track-module apparatus is not
limited to a rotating power shaft of the vehicle. Other
power-source configurations are contemplated, such as a hydraulic
motor or other power source on the vehicle or a mechanical,
hydraulic or other power source directly mounted on the apparatus
itself.
[0105] FIG. 18 is perspective drawing of a fifth alternative
track-module embodiment 200. FIG. 19 is a side elevation drawing of
the track-module embodiment 200. Track-module embodiment 200
includes many of the same components as track-module apparatus 10
as shown in FIGS. 1-6B, and thus FIGS. 18 and 19 do not repeat many
reference numbers from these previous figures. Only those
components which are different from previously-described
embodiments and certain others for clarity of description are
marked with reference numbers.
[0106] As in previous track-apparatus embodiments, embodiment 200
includes bogie-suspension apparatus which includes bogie assembly
46, leading suspension element 68, and trailing suspension element
70. Bogie assembly 46 includes bogie mount 48 and a plurality of
bogie wheels (56, 60 and 64 in embodiment 200). Bogie-mount 48
includes bogie-mount arm 102, bogie-mount forward portion 50,
bogie-mount rearward portion 52, and bogie-mount middle portion 54.
Embodiment 200 also includes axes and pivots as previously
described in other embodiments in this document.
[0107] Track-module embodiment 200 differs from all of the
previously-described embodiments of track-module apparatus in that
movements of leading suspension element upper end 68U at first
suspension joint 82p and trailing suspension element upper end 70U
at second suspension joint 86p are interdependent. Such
interdependence is brought about by track-module apparatus 200
including unitary leading and trailing idler arms 202 (unitary
structure 202). The unitary character of such arm structure is
indicated by reference number 202 on both leading and trailing
portions of unitary structure 202. As best seen in FIG. 18, the
leading and trailing portions of the unitary structure 202 are
rigidly connected to form a single structure with leading and
trailing portions rotatably attached to frame 12 at suspension-arm
axis 44. Since first suspension joint 82p and second suspension
joint 86p are on opposite sides of unitary structure 202 with
respect to suspension arm axis 44, upward movement of one of the
suspension joints occurs with downward movement of the other. The
relative magnitudes of the movements are determined by the
distances of each suspension joint from suspension-arm axis 44.
[0108] Leading suspension element lower end 68L at first
bogie-assembly pivot 84p and trailing suspension element lower end
70L at second bogie-assembly pivot 88p connect bogie mount 48 at
rearward bogie-mount connection 92 and forward bogie-mount
connection 94, respectively.
[0109] In embodiment 200, bogie assembly 46 includes third load-
and ground-responsive suspension joint 78 which is rotatably
attached to unitary structure 202 and thus movements of suspension
joint 78 and first and second suspension joints are all
interdependent. In embodiment 200 as in the previously-described
embodiments, suspension joint 78 only transmits lateral forces
between unitary structure 202 and bogie assembly 46.
[0110] In embodiment 200, first and second suspension joints 82p
and 86p and first and second bogie-assembly pivots 84p and 88p all
utilize spherical bearings as previously described. Although single
degree-of-freedom bearings may also be used, but it is preferred
that these joints/pivots each provide a plurality of rotational
degrees-of-freedom.
[0111] While the principles of this invention are shown and
described here in connection with specific embodiments, it is to be
understood that such embodiments are by way of example and are not
limiting.
* * * * *