U.S. patent application number 12/827269 was filed with the patent office on 2012-01-05 for control system and vehicle incorporating same.
Invention is credited to Gary L. Nicholson, Clark S. Papke.
Application Number | 20120000172 12/827269 |
Document ID | / |
Family ID | 45398646 |
Filed Date | 2012-01-05 |
United States Patent
Application |
20120000172 |
Kind Code |
A1 |
Papke; Clark S. ; et
al. |
January 5, 2012 |
CONTROL SYSTEM AND VEHICLE INCORPORATING SAME
Abstract
A vehicle including a linkage-based motion control system for
varying a parameter (e.g., velocity) of the vehicle as a geometric
relationship between a vehicle input (e.g., velocity control lever)
and a vehicle output (e.g., drive train) is modified. In one
embodiment, the control system provides a linkage that allows a
fixed level of input applied to the control lever to produce a
repeatable output to a variable drive unit even as the drive unit
is moved relative to the control lever. In another embodiment, an
adjustable stop for use with setting a terminal position of a
control lever (e.g., a velocity control lever) is provided.
Accordingly, the maximum potential speed of the vehicle may be
adjusted (e.g., reduced) without altering the speed of the vehicle
engine.
Inventors: |
Papke; Clark S.; (Cortland,
NE) ; Nicholson; Gary L.; (Beatrice, NE) |
Family ID: |
45398646 |
Appl. No.: |
12/827269 |
Filed: |
June 30, 2010 |
Current U.S.
Class: |
56/14.7 ;
180/336 |
Current CPC
Class: |
A01D 34/82 20130101;
A01D 2034/6843 20130101 |
Class at
Publication: |
56/14.7 ;
180/336 |
International
Class: |
B60K 20/02 20060101
B60K020/02; A01D 34/00 20060101 A01D034/00 |
Claims
1. A vehicle, comprising: a chassis; a platform suspended from the
chassis; a platform displacement mechanism configured to move the
platform, relative to the chassis, between a first position and a
second position; a variable drive unit mounted to the platform and
comprising an input member movable, relative to a housing of the
drive unit, between a first position and a second position; a
control lever attached to the chassis and operatively connected to
the drive unit, the control lever configured to vary a position of
the input member relative to the housing, the control lever movable
incrementally between a first position corresponding to the first
position of the input member, and a second position corresponding
to the second position of the input member; and a control linkage
system comprising: a pivot link pivotally attached to the chassis
at a chassis pivot; a control link comprising: a first end
connected to the pivot link; and a second end connected to the
control lever; and a drive link comprising: a first end pivotally
connected to the pivot link at a first drive link pivot; and a
second end pivotally connected to the input member at a second
drive link pivot; wherein the linkage system is configured to
maintain, as the platform is moved between the first and second
positions, both the position of the input member relative to the
drive unit, and a position of the control link relative to the
chassis.
2. The vehicle of claim 1, further comprising a prime mover
operatively coupled to the drive unit to provide power to the
same.
3. The vehicle of claim 1, wherein the pivot link comprises: a
bellcrank including a first arm pivotally connected to the control
link; and a second arm defining the first drive link pivot.
4. The vehicle of claim 1, wherein the platform displacement
mechanism comprises a platform link pivotally attached to: the
chassis at a platform chassis pivot; and to the platform at a
platform attachment point, wherein a linear distance between the
platform chassis pivot and the platform attachment point is equal
to a linear distance between the first and second drive link
pivots.
5. The vehicle of claim 4, wherein a line extending between the
platform chassis pivot and the platform attachment point is
parallel to a line extending between the first and second drive
link pivots.
6. The vehicle of claim 1, wherein the input member is pivotable
about an input pivot of the housing of the drive unit, and wherein
a linear distance between the input pivot and the second drive link
pivot is equal to a linear distance between the chassis pivot and
the first drive link pivot.
7. The vehicle of claim 6, wherein a line extending between the
input pivot and the second drive link pivot is parallel to a line
extending between the chassis pivot and the first drive link
pivot.
8. A vehicle, comprising: a chassis supported by one or more drive
wheels; a platform suspended from the chassis; a platform lift
mechanism configured to raise and lower the platform, relative to
the chassis, between a first position and a second position; a
variable drive unit attached to the platform and comprising an
input arm movable, relative to a housing of the drive unit, between
a first position and a second position; a prime mover attached to
either the platform or the chassis and coupled to the drive unit to
provide power to the same; a control lever pivotally attached to
the chassis and operatively connected to the drive unit, the
control lever configured to vary a position of the input arm
relative to the housing of the drive unit, the control lever
movable incrementally between a first position corresponding to the
first position of the input arm, and a second position
corresponding to the second position of the input arm; and a drive
motion control linkage system comprising: a bellcrank pivotally
attached to the chassis at a chassis pivot, the bellcrank
comprising a first arm and a second arm; a control link having a
first end connected to the first arm at a control link pivot, and a
second end connected to the control lever; and a drive link
comprising: a first end pivotally connected to the second arm of
the bellcrank at a first drive link pivot; and a second end
pivotally connected to the input arm at a second drive link
pivot.
9. The vehicle of claim 8, wherein the drive motion control linkage
system is configured to maintain, as the platform is moved between
the first and second positions, both the position of the input arm
relative to the housing of the drive unit, and a position of the
control link relative to the chassis.
10. The vehicle of claim 8, wherein the platform further comprises
a lawn mower cutting deck.
11. The vehicle of claim 8, wherein incremental movement of the
control lever from the first position to the second position
results in corresponding incremental movement of the input arm,
relative to the housing of the drive unit, from the first position
to the second position regardless of whether the platform is in, or
is moving between, the first position, the second position, or any
intermediate position.
12. The vehicle of claim 8, wherein the drive motion control
linkage system, the variable drive unit, and the control lever are
associated with a first side of the vehicle, and the vehicle
further comprises a second drive motion control linkage system, a
second variable drive unit, and a second control lever associated
with a second opposite side of the chassis.
13. The vehicle of claim 8, further comprising a stop bar
configured to limit movement of the control lever, the stop bar
pivotally attached to the chassis for pivoting between two
positions, wherein the stop bar is pivotable about a transverse
axis coincident with a pivot axis about which the control lever
pivots.
14. The vehicle of claim 13, wherein the stop bar further comprises
a lock mechanism configured to lock the stop bar at either of the
two positions or at a position intermediate the two positions.
15. The vehicle of claim 8, wherein the platform lift mechanism
comprises one or more platform bellcranks each pivotally attached
to: the chassis at a platform chassis pivot; and to the platform at
a platform pivot, wherein a linear distance between the platform
chassis pivot and the platform pivot is equal to a linear distance
between the first and second drive link pivots.
16. The vehicle of claim 15, wherein a line extending between the
platform chassis pivot and the platform pivot is parallel to a line
extending between the first and second drive link pivots.
17. The vehicle of claim 8, wherein the input arm is pivotable
about an input pivot of the housing of the drive unit, and wherein
a linear distance between the input pivot and the second drive link
pivot is equal to a linear distance between the chassis pivot and
the first drive link pivot.
18. The vehicle of claim 17, wherein a line extending between the
input pivot and the second drive link pivot is parallel to a line
extending between the chassis pivot and the first drive link
pivot.
19. A lawn mowing vehicle comprising: a chassis; transversely
opposing first and second drive wheels coupled to the chassis; a
platform suspended from the chassis; a platform lift mechanism
configured to move the platform between a first position and a
second position relative to the chassis; first and second variable
drive units attached to the platform and operatively coupled to the
first and second drive wheels, respectively, wherein each drive
unit comprises an input arm pivotable, about an input pivot of a
housing of the drive unit, between a first position and a second
position; a prime mover attached to either the platform or the
chassis and operatively coupled to both the first and second
variable drive units to provide power to the same; first and second
drive control levers pivotally attached to the chassis and coupled
to, and operable to independently vary a position of, the input arm
of the first and second variable drive units, respectively, each
control lever movable incrementally between a first position
corresponding to the first position of its respective input arm,
and a second position corresponding to the second position of its
respective input arm; and a drive motion control linkage system
comprising: first and second bellcranks each pivotally attached to
the chassis at a chassis pivot; first and second control links each
comprising: a first end connected to the first and second
bellcranks, respectively; and a second end connected to the first
and second drive control levers, respectively; and first and second
drive links each comprising: a first end pivotally connected, at a
first drive link pivot, to a second arm of the first and second
bellcranks, respectively, and a second end connected to the input
arm, at a second drive link pivot, of the first and second variable
drive units, respectively.
20. The vehicle of claim 19, further comprising a hydraulic wheel
motor associated with each of the first and second drive wheels,
each motor attached to the chassis and operatively connected to one
of the first and second variable drive units.
21. The vehicle of claim 19, wherein the drive motion control
linkage system is configured so that movement of the platform
between the first and second positions does not result in movement
of either: the first or second bellcranks relative to the chassis;
or the input arms of the first and second drive units relative to
the respective housings of the first and second drive units.
22. The vehicle of claim 19, wherein movement of the first drive
control lever from the first position to the second position
results in movement of the input arm of the first variable drive
unit from the first position to the second position regardless of
whether the platform is in, or is moving between, the first
position, the second position, or any intermediate position.
23. The vehicle of claim 19, wherein the platform lift mechanism
comprises one or more platform bellcranks each pivotally attached
to: the chassis at a platform chassis pivot; and to the platform at
a platform pivot, wherein a linear distance between the platform
chassis pivot and the platform pivot is equal to a linear distance
between the first and second drive link pivots of the first drive
link.
24. The vehicle of claim 23, wherein a line extending between the
platform chassis pivot and the platform pivot is parallel to a line
extending between the first and second drive link pivots of the
first drive link.
25. The vehicle of claim 19, wherein one or both of the first and
second drive links is curvilinear.
26. The vehicle of claim 19, further comprising an adjustable stop
bar positioned to form a stop surface for the first drive control
lever when the first drive control lever is in the second position,
the stop bar pivotally connected to the chassis for pivoting
between two positions about a pivot axis coincident with a pivot
axis of the first drive control lever.
27. The vehicle of claim 26, wherein the stop bar further comprises
a lock mechanism configured to lock the stop bar at either of the
two positions or at a position intermediate the two positions.
28. A vehicle comprising: a chassis; a control lever pivotally
attached to the chassis for pivoting about a pivot axis and
operable to vary a speed of a variable drive unit, the control
lever movable incrementally between a first position corresponding
to a first position of an input arm of the drive unit, and a second
position corresponding to a second position of the input arm; and a
stop bar positioned to form a stop surface for the control lever
when the control lever is in the second position, the stop bar
pivotally connected to the chassis for pivoting between two
positions about a pivot axis that is coincident with the pivot axis
of the control lever.
29. The vehicle of claim 28, wherein the stop bar further comprises
a lock mechanism configured to lock the stop bar at either of the
two positions or at a position intermediate the two positions.
30. The vehicle of claim 28, further comprising a lawn mower
cutting deck operatively attached to the chassis.
Description
TECHNICAL FIELD
[0001] Embodiments of the present invention relate generally to
motion control systems and, for example, to vehicles (e.g., lawn
mowers) and motion control systems for accommodating relative
movement between a working and a fixed portion of the vehicle.
BACKGROUND
[0002] Power vehicles for carrying out diverse tasks are known. For
instance, power lawn mowers are well known for use in turf and lawn
maintenance. Such mowers may range from small, walk-behind mowers
such as those used by homeowners, to professional grade riding
mowers adept at mowing larger areas. While embodiments of the
present invention may be directed to control systems for use with a
wide variety of power vehicles, it will, for the sake of brevity,
be described with respect to power riding or walk behind
mowers.
[0003] Power mowers typically incorporate a prime mover (e.g.,
internal combustion engine) and a variable, e.g., hydraulic, drive
system. The drive system may include left and right hydraulic
motors coupled to left and right drive wheels, respectively. Power
may be transmitted from the prime mover to the left and right
hydraulic motors, e.g., via one or more pumps, to drive the left
and right drive wheels independently. The rotational speed and
direction of each drive wheel may then be controlled by associated
drive control levers manipulated by an operator. By manipulating
the control levers independently, each drive wheel can be
separately driven forward or backwards at varying speeds. Thus, the
mower may be propelled forwardly or in reverse. By powering one
wheel in the forward direction and slowing, stopping, or powering
the opposite wheel in the reverse direction, the mower can execute
a turn.
[0004] With many conventional mowers, the engine and hydraulic
pumps are attached to a frame of the mower, while the cutting deck
is adjustably positionable at varying elevations relative to the
frame to provide for different cutting heights. While effective,
moving the cutting deck relative to the engine does have drawbacks.
For example, with a belt-powered cutting deck, it is desirable to
ensure that the fleeting angle (the belt angle formed between the
engine driving sheave and the driven sheave(s) of the cutting deck)
is maintained within an acceptable range as the deck moves up and
down to minimize belt separation and/or wear. Depending on the
distance between the engine and deck, the range of acceptable
fleeting angles may be limited.
[0005] Another issue with some mowers concerns positioning of the
drive control levers. For instance, each drive control lever may
generally be positioned between a neutral and a full forward (and a
full reverse) position. The levers are generally sized and
configured so that the operator may manipulate the levers over
their normal range of motion (e.g., from neutral to full forward)
without relocating his or her hands. In the full forward position,
the levers may be configured to rest against stationary stop bars.
Such a configuration permits the operator to hold the levers
against a fixed stop during normal operation, reducing potential
fatigue in the hands, wrists, and arms. The fixed stop may also
provide a degree of lever stability, minimizing inadvertent lever
movement as a result of vehicle motion.
[0006] While effective, this full forward position may result in a
vehicle speed in excess of what is desired for some mowing tasks.
To reduce the speed, the operator may back the control levers off
from the full forward position. Unfortunately, this technique may
prevent the operator from resting the levers against the fixed
stops. Alternatively, the engine throttle may be reduced. While
throttle reduction is effective at reducing maximum vehicle speed,
it also reduces the rotational speed of any attached implements,
e.g., the blades of the cutting deck. As a result, cutting
efficiency of the mower may be reduced.
SUMMARY
[0007] The present invention may overcome these and other issues
with prior art mowers by providing a vehicle (e.g., lawn mower)
having a chassis; a platform suspended from the chassis; and a
platform displacement mechanism configured to move the platform,
relative to the chassis, between a first position and a second
position. A variable drive unit is also provided and mounted to the
platform. The drive unit includes an input member movable, relative
to a housing of the drive unit, between a first position and a
second position. A control lever is attached to the chassis and
operatively connected to the drive unit. The control lever is
configured to vary a position of the input member relative to the
housing, wherein the control lever is movable incrementally between
a first position corresponding to the first position of the input
member, and a second position corresponding to the second position
of the input member. A control linkage system is also provided and
includes: a pivot link pivotally attached to the chassis at a
chassis pivot; and a control link. The control link includes: a
first end connected to the pivot link; and a second end connected
to the control lever. The linkage system also includes a drive link
having: a first end pivotally connected to the pivot link at a
first drive link pivot; and a second end pivotally connected to the
input member at a second drive link pivot. The linkage system is
configured to maintain, as the platform is moved between the first
and second positions, both the position of the input member
relative to the drive unit, and a position of the control link
relative to the chassis.
[0008] In another embodiment, a vehicle is provided and includes: a
chassis supported by one or more drive wheels; a platform suspended
from the chassis; a platform lift mechanism configured to raise and
lower the platform, relative to the chassis, between a first
position and a second position; and a variable drive unit attached
to the platform. The drive unit includes an input arm movable,
relative to a housing of the drive unit, between a first position
and a second position. A prime mover is attached to either the
platform or the chassis and coupled to the drive unit to provide
power to the same. A control lever is pivotally attached to the
chassis and operatively connected to the drive unit, wherein the
control lever is configured to vary a position of the input arm
relative to the housing of the drive unit. In one embodiment, the
control lever is movable incrementally between a first position
corresponding to the first position of the input arm, and a second
position corresponding to the second position of the input arm.
Also included is a drive motion control linkage system having a
bellcrank pivotally attached to the chassis at a chassis pivot,
wherein the bellcrank includes a first arm and a second arm. The
linkage system also includes: a control link having a first end
connected to the first arm at a control link pivot, and a second
end connected to the control lever; and a drive link. The drive
link includes: a first end pivotally connected to the second arm of
the bellcrank at a first drive link pivot; and a second end
pivotally connected to the input arm at a second drive link
pivot.
[0009] In yet another embodiment, a vehicle is provided that
includes: a chassis; and a control lever pivotally attached to the
chassis for pivoting about a pivot axis, the control lever operable
to vary a speed of a variable drive unit. The control lever is
movable incrementally between a first position corresponding to a
first position of an input arm of the drive unit, and a second
position corresponding to a second position of the input arm. The
vehicle further includes a stop bar positioned to form a stop
surface for the control lever when the control lever is in the
second position. The stop bar is pivotally connected to the chassis
for pivoting between two positions about a pivot axis that is
coincident with the pivot axis of the control lever.
[0010] The above summary is not intended to describe each
embodiment or every implementation of the present invention.
Rather, a more complete understanding of the invention will become
apparent and appreciated by reference to the following Detailed
Description of Exemplary Embodiments and claims in view of the
accompanying figures of the drawing.
BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWING
[0011] The present invention will be further described with
reference to the figures of the drawing, wherein:
[0012] FIG. 1 is a rear perspective view of an exemplary vehicle,
e.g., power walk-behind/stand-on mower, incorporating a control
system, e.g., motion control linkage system, and a platform lift
mechanism, in accordance with embodiments of the present invention,
the mower illustrated with a standing platform in a deployed
position;
[0013] FIG. 2 is a front perspective view of the mower of FIG. 1
illustrating an operator control area;
[0014] FIGS. 3A-3B (collectively referred to as FIG. 3) illustrate
portions of the exemplary platform lift mechanism of the mower of
FIGS. 1 and 2, wherein: FIG. 3A is a partial side elevation view of
the platform lift mechanism; and FIG. 3B is a perspective view of a
portion of the mechanism of FIG. 3A;
[0015] FIG. 4 is a side elevation view of the mower of FIGS. 1 and
2 with some structure removed to illustrate the platform lift
mechanism, the motion control linkage system, and the control
area;
[0016] FIG. 5 is an enlarged view of the control area of FIG.
4;
[0017] FIG. 6 is a partial perspective view of the mower of FIGS. 1
and 2 illustrating the motion control linkage system;
[0018] FIG. 7 is a partial enlarged side elevation view of the
mower of FIGS. 1 and 2 illustrating the platform in a first or
fully raised position, and the motion control linkage system in
both a first or neutral position (solid lines) and a second or
maximum forward position (broken lines);
[0019] FIG. 8 is a partial enlarged side elevation view similar to
FIG. 7 but with the platform shown in a second or fully lowered
position, and the motion control linkage system shown in the first
or neutral position;
[0020] FIG. 9 is a partial side elevation view of the control area
with a control lever shown in the first or neutral position and a
control lever stop bar shown in a first position "A"; and
[0021] FIG. 10 is a partial side elevation view of the control area
similar to FIG. 9 but with the control lever in the first or
neutral position and the control lever stop bar in a second
position "B."
[0022] The figures are rendered primarily for clarity and, as a
result, are not necessarily drawn to scale. Moreover, certain
structure (e.g., various chassis portions/components, fasteners,
bearings, cables, and hydraulic components (including but not
limited to: conduits; hoses; and fittings, etc.)) may be removed
from some or all of the views to better illustrate aspects of the
depicted embodiments, or where inclusion of such
structure/components is not necessary to an understanding of the
various embodiments of the invention. The removal of such
structure/components, however, is not to be interpreted as limiting
the scope of the invention in any way.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0023] In the following detailed description of illustrative
embodiments of the invention, reference is made to the accompanying
figures of the drawing which form a part hereof, and in which are
shown, by way of illustration, specific embodiments in which the
invention may be practiced. It is to be understood that other
embodiments may be utilized and structural changes may be made
without departing from the scope of the instant invention.
[0024] Embodiments of the present invention are generally directed
to vehicles such as lawn mowers and the like, and to motion control
systems for use with the same. Embodiments of the present invention
may include a linkage-based motion control system for accurately
adjusting a parameter (e.g., velocity) of the vehicle even as a
geometric relationship between an input (e.g., velocity control
lever) and an output (e.g., drive train) of the vehicle is
modified. As a result, the vehicle may respond to a given operator
input in a repeatable manner regardless of the vehicle's geometric
configuration.
[0025] While the exemplary motion control linkage system is
described and illustrated herein as a velocity control system,
alternative embodiments may address systems for controlling most
any parameter wherein a location of a control input may be varied
relative to the associated controlled device.
[0026] Other embodiments may further include an adjustable stop bar
for use with adjusting a terminal position of a control lever
(e.g., a velocity control lever). Accordingly, the maximum
potential speed of the vehicle may be adjusted without altering a
throttle setting of the vehicle.
[0027] FIG. 1 illustrates an exemplary self-propelled vehicle,
e.g., a walk-behind or ride-on lawn mowing vehicle 100 that may
incorporate a motion control linkage system 300 (see FIG. 4) in
accordance with one embodiment of the present invention. While, for
the sake of brevity, embodiments of the invention are herein
described with respect to a walk-behind/stand-on lawn mower
(hereinafter generically referred to merely as a "mower"), those of
skill in the art will realize that the invention is equally
applicable to other types of walk-behind, ride-behind (e.g., such
as those utilizing sulkies), and conventional ride-on mowers, as
well as to most any other walk-behind, ride-behind, or ride-on
self-propelled utility vehicle (e.g., aerator, snow blower,
blower/vacuum, spreader, etc.).
[0028] While the general construction of the mower 100 is not
necessarily central to an understanding of the invention (e.g.,
other mower configurations may be utilized without departing from
the scope of the invention), one configuration is now briefly
described. The mower 100 may also be, in some respects, similar to
the mowers described in U.S. patent application Ser No. 12/275,381,
the content of which is incorporated herein by reference in its
entirety.
[0029] FIGS. 1 and 2 illustrate the exemplary mower 100 having a
chassis 102 and a power source or prime mover, e.g., internal
combustion engine 104. A pair of transversely opposing, ground
engaging drive members, e.g., first and second drive wheels 106,
may be coupled for rotation to opposing sides of the chassis to
support and propel the mower 100 relative to a ground surface 103.
Each drive wheel 106 may be powered by its own hydraulic wheel
motor 107 (only right side motor 107b shown in FIG. 1) attached to
the chassis 102 that receives power from, at least in one
embodiment, its own variable drive unit, e.g., hydraulic drive unit
such as a hydraulic pump 110 (see FIGS. 4 and 6), that is itself
powered by the engine 104. While described herein as a hydraulic
drive unit, other embodiments may utilize other variable drive
units, e.g., electrical or mechanical systems, without departing
from the scope of the invention.
[0030] The pumps 110 and the engine 104 may be mounted or attached
to a platform 112 (see FIG. 4) that, as described in more detail
below, is suspended from, and movable relative to, the chassis 102
via a platform displacement, e.g., lift, mechanism. Alternatively,
one or both of the pumps engine could be attached to the chassis.
The engine 104 may include an output shaft having a sheave (not
shown) that provides power to an input sheave 118 on each pump 110
via an endless belt 117 as represented in broken lines in FIG. 7.
In the illustrated embodiment, the platform 112 may be raised and
lowered between a first and a second position by the platform lift
mechanism.
[0031] As used herein, relative terms such as "left," "right,"
"fore," "forward," "aft," "rearward," "top," "bottom," "upper,"
"lower," "horizontal," "vertical," and the like are from the
perspective of one operating the mower 100 while the mower is in an
operating configuration, e.g., while the mower 100 is positioned
such that the wheels 106 and 108 rest upon the generally horizontal
ground surface 103 as shown in FIGS. 1 and 2. These terms are used
herein to simplify the description, however, and not to limit the
scope of the invention in any way.
[0032] Moreover, the suffixes "a" and "b" may be used throughout
this description to denote various left- and right-side
parts/features, respectively. However, in most pertinent respects,
the parts/features denoted with "a" and "b" suffixes are
substantially identical to, or mirror images of, one another. It is
understood that, unless otherwise noted, the description of an
individual part/feature (e.g., part/feature identified with an "a"
suffix) also applies to the opposing part/feature (e.g.,
part/feature identified with a "b" suffix). Similarly, the
description of a part/feature identified with no suffix may apply,
unless noted otherwise, to both the corresponding left and right
part/feature.
[0033] Operator controls, some of which are described below, may
permit independent control of the speed and direction of each drive
wheel 106 (e.g., each pump 110), allowing control of mower 100
speed and direction from either a walking or riding (e.g.,
standing) position generally behind the mower 100. A pair of front
swiveling caster wheels 108 (only right wheel visible in FIG. 1),
which may be connected to forwardly extending chassis rails, may
support the front of the mower 100 in rolling engagement with the
ground surface 103.
[0034] Although the illustrated mower has the drive wheels 106 in
the rear and caster wheels 108 in front, this configuration is not
limiting. For example, other embodiments may reverse the location
of the wheels, e.g., drive wheels in front and driven or passive
wheels in back. Moreover, other configurations may use different
wheel configurations altogether, e.g., a tri-wheel configuration.
Moreover, while the mower 100 is illustrated as incorporating a
hydraulic drive system, other drive systems, e.g., gear or pulley
driven systems, may also be utilized without departing from the
scope of the invention.
[0035] A lawn mower cutting deck 114 may be mounted to a lower side
of the platform 112 generally longitudinally between the drive
wheels 106 and the caster wheels 108. The cutting deck 114 may
include one or more cutting blades 115 (see, e.g., FIG. 4) as is
known in the art. The cutting blades may be operatively powered,
via spindles passing through to the deck, by a belt 116 (see also
FIG. 4) driven by the engine 104. During operation, power is
selectively delivered to the cutting deck 114, whereby the blades
115 rotate at a speed sufficient to sever grass and other
vegetation passing beneath the cutting deck.
[0036] The exemplary mower 100 may also include a standing platform
120 that may be moved between a deployed position as shown in FIGS.
1 and 2, and a stowed position (not shown). In the deployed
position, an operator may stand upon the standing platform 120
during vehicle operation. Alternatively, the standing platform 120
may be moved to the stowed position to accommodate the operator in
a walk-behind configuration.
[0037] As shown in FIG. 2, the mower 100 may further include an
operator control area 200. In the illustrated embodiment, the
control area 200 may include various operator controls that are
mounted to upwardly extending portions of the chassis 102 near the
rearward end of the mower such that the controls are located within
comfortable reach of the operator standing either behind the mower
or upon the platform 120.
[0038] The control area 200 may include any number of controls
necessary or beneficial to the operation of the mower 100. For
instance, a parking brake handle 202 (see FIG. 2) may selectively
activate a brake (e.g., brake members 122 shown in FIGS. 1 and 2)
when the mower is parked. Other controls, including for example, a
throttle lever to control the speed of the engine 104, engine
choke, hour meter, and PTO deck engagement control (to initiate and
terminate power delivery to the cutting blades of the mower deck
114) may also be provided. Still further, one or more control
levers, e.g., drive control levers 302a and 302b, may be provided.
The drive control levers 302 may be attached, e.g., pivotally
attached, to the chassis 102 and be configured to control the speed
and direction of the drive wheels 106a and 106b, respectively,
(e.g., via their associated pumps 110a and 110b) as described in
more detail below.
[0039] As shown in FIG. 3A, a platform displacement or lift
mechanism 220 may also be provided to permit the operator to move
(e.g., raise and lower) the platform 112, and thus the cutting deck
114, relative to the chassis 102 between at least a first and
second position. In the illustrated embodiment, the mechanism may
be manipulated by an adjustment lever 204 that is itself pivotally
attached to the chassis 102 at a pivot 222 near the control area
200. In the illustrated embodiment, the mower may further include a
pin, e.g., tethered pin 227 (see FIG. 2) operable to engage one of
many openings 226 formed in a plate 224 of the frame. To reposition
the lever 204 (and thus the platform 112), the lever may be
manually lifted upwardly to expose the opening 226 corresponding to
the desired platform height. Once the platform is located at or
slightly above the desired height, the pin 227 may be inserted into
the appropriate opening 226. By then releasing the lever 204, the
weight of the platform 112 may then rest against the pin to
maintain the platform at the desired height. While illustrated
herein as incorporating a manual platform lift mechanism, other
embodiments may substitute a powered, e.g., hydraulic or electric
lift mechanism, without departing from the scope of the
invention.
[0040] As used herein, the term "pivot" refers to most any
structure or feature that permits one component to pivot or rotate
relative to another. The pivots described and illustrated herein
may be configured in most any manner that permits such relative
motion. For instance, an axle, bolt, or shaft, optionally
surrounded by a bushing or bearing, may be used to form the pivot.
As various pivot configurations are well known in the art, further
detail regarding these components as they relate to embodiments of
the present invention are not provided herein. Moreover, for
illustration purposes, a pivot may be identified in the figures by
pointing either to the general structure defining the pivot, or to
a pivot axis defined by the pivot.
[0041] As shown in the embodiment of FIGS. 3A and 3B, the lever 204
may be pivotally attached, at a distance offset from the pivot 222,
to a connecting rod 228. At a lower end, the connecting rod 228 may
be pivotally connected, via a pivot 229 (see also FIG. 3B), to a
rear platform link or bellcrank 230. The rear bellcrank is, in
turn, itself pivotally attached to the chassis 102 at a platform
chassis pivot 232. A first end 234 of the rear platform bellcrank
230 may be pivotally attached to a tie rod 236 extending forwardly
where it attaches to a first end 238 of a similar front platform
link or bellcrank 240. The front platform bellcrank 240 may also,
like the bellcrank 230, be pivotally attached to the chassis 102 at
a platform chassis pivot 242. A second end 244 of the front
platform bellcrank 240 and a second end 248 of the rear platform
bellcrank 230 may be pivotally attached to the platform 112 at a
platform attachment point, e.g., platform pivot 247. In the
illustrated embodiment, the front platform/deck bellcrank 240 may
utilize an intermediate bracket 246 as shown in FIG. 3A.
[0042] The front platform bellcrank 240 may be of the same size and
geometry as the rear platform bellcrank 230 and, as a result of the
tie rod 236, may be oriented similarly. Accordingly, movement of
the lever 204 downwardly (e.g., in the clockwise direction in FIG.
3A) may result in pivotal movement of the front and rear platform
bellcranks 230, 240 about the pivots 232 and 242, respectively, in
the clockwise direction, effectively lowering the platform 112 and
the deck 114. Conversely, raising the lever 204, e.g., pivoting it
in a counterclockwise direction about the pivot 222, results in
raising the platform 112 and deck 114.
[0043] As illustrated in FIG. 3B, the second end 248 of the rear
platform bellcrank 230 may support (e.g., be welded or otherwise
integral with or fixed to) a shaft 251 that extends transversely
across the mower 100. The shaft 251 may extend from the rear
platform bellcrank 230 through a transversely spaced link 249 and
through one or more brackets 254 (e.g., one on each side of the
platform) that support the platform 112. The brackets 254 may hang
on the shaft 251, thereby providing an effective pivoting
relationship (between the platform 112 and the bellcrank 230) about
the centerline of the shaft. The link 249 may, at a first end, be
welded to the shaft 251, and at its opposite end, connect to a
shaft that defines the pivot 229. On the opposite side of the mower
100, the shaft 251 may connect to a similar or identical mechanism
(e.g., to another front and rear platform bellcrank 230, 240, link
249, and another tie rod 236 (see FIGS. 3A and 3B)) on the opposite
side of the mower).
[0044] As a result of the described geometry, the platform 112 and
deck 114 may be attached and lifted relative to the chassis 102 at
four separate lift points. Moreover, the respective front and rear
platform bellcranks 230, 240 and tie rods 236 may form a 4-bar
linkage on each side of the mower 100 that keeps the platform 112
generally level at any selected elevation (even though described as
"level," the platform may be configured such that it is slightly
inclined (e.g., inclined forwardly) at all elevation settings).
[0045] To assist the operator with raising and lowering the
platform 112/deck 114, springs 250 may optionally be provided on
one or both sides of the mower 100. An upper end of each spring may
attach to the chassis 102 (see FIG. 1), while a lower end of each
spring may operatively connect to the lever arms(s) 230, e.g., it
may connect to a chain that is attached to an auxiliary lever arm
252. The lever arm 252 may be rigidly attached to (e.g., via a
connecting tube), but transversely offset from, the lever arm 230
as shown in FIG. 3B so that it pivots in unison with the rear
bellcrank.
[0046] Using the exemplary platform lift mechanism 220 described
and illustrated herein, the platform 112 may move through an arc
255 (see FIG. 3A) as it is raised and lowered. This arc may be
defined by a linear distance 256 between the platform chassis pivot
232 (or 242) and the platform attachment point/pivot 247 of the
respective platform bellcrank 230 (or 240). In the illustrated
embodiment, the distance 256 is identical for all (e.g., both front
and rear) platform bellcranks.
[0047] As described elsewhere herein, the engine 104, cutting deck
114, and hydraulic pumps 110 (see FIGS. 4 and 6) may all be
attached to the platform 112 and thus move up and down as the
platform lift system 220 is manipulated (see also FIGS. 7 and 8).
This may, as stated elsewhere herein, provide for relatively planar
belt 116 routing between these components, reducing belt wear and
potential belt roll-off that may occur in systems having greater
fleeting angles. However, as the hydraulic pumps 110 move relative
to the chassis 102 and thus to the control levers, a conventional
linkage may cause unintended movement of input arms 332 of the
pumps 110 (see, e.g., FIG. 7) merely as a result of platform
repositioning.
[0048] Motion control linkage systems in accordance with
embodiments of the present invention may, however, avoid these
problems, i.e., they may provide consistent and repeatable input to
the hydraulic pumps 110, for a given position of the respective
drive control levers 302, regardless of platform location. As a
result, consistent mower response may be provided.
[0049] As shown in FIGS. 1, 2, and 4, the exemplary motion control
linkage system 300 may include a first or left drive control lever
302a and a second or right drive control lever 302b pivotally
attached to the chassis 102. The control levers 302 may be
configured to pivot about a transverse horizontal axis 307 (see
FIG. 6) from a first or neutral position towards both a first or
forward stop bar 304, and a second or rearward stop bar 306. One or
both of the control levers 302 (e.g., 302b as shown in FIG. 2)
could be biased for pivotal outward movement (e.g., in a direction
309 about an axis generally parallel to a longitudinal axis of the
mower 100). Such a configuration may permit, upon pivotal inward
movement of the control lever 302b by the operator to the position
shown in FIGS. 1 and 2, activation of an operator presence switch
(not shown). As is recognized in the art, activation of the switch
may be requisite to activation of some of the mower subsystems.
[0050] The control levers 302 may also be biased to the
intermediate, neutral position between the two stop bars 304 and
306 for mower operation as shown in FIGS. 1, 2 and 4. Each control
lever 302 may be movable between at least the first or neutral
position (shown in FIG. 4), which corresponds to a first or zero
forward velocity of its respective drive wheel 106/pump 110, and an
second or engaged position (abutting the forward stop bar 304),
which corresponds to a second or maximum forward velocity of its
respective drive wheel/pump. Stated another way, each control lever
302 may independently vary a velocity of its respective drive wheel
106 incrementally between a first or zero forward velocity and a
second or predetermined maximum forward velocity without varying
the engine throttle. Each lever 302 may additionally be movable to
a third position (abutting the rear stop bar 306) corresponding to
a third or predetermined maximum reverse velocity of its respective
drive wheel. In the illustrated embodiment, the neutral position of
the control levers 302 may be located more closely to the rearward
stop bar 306 to provide a greater range of movement for forward
travel.
[0051] FIG. 5 illustrates an enlarged partial view of the control
area of FIG. 4. As illustrated in this view, each control lever 302
may pivot relative to the chassis 102 at the transverse horizontal
axis 307 (see also FIG. 6) defined by a pivot 308. Each control
lever 302 may also include a secondary lever arm 310 (which is
offset from the pivot 308) that pivotally receives an upper end of
a control link 312 at a pivot 313. The control link 312 may be
segmented and include an adjustment mechanism 314 to lengthen or
shorten the control link after installation. As one can appreciate
from FIG. 5, movement of the control lever 302 towards the forward
stop bar 304 (or towards the rear stop 306) results in movement of
the control link upwardly (or downwardly) as indicated by the
arrows in this view.
[0052] FIG. 6 illustrates a perspective view of the motion control
linkage system 300. The platform 112 and the pumps 110 are also
illustrated in this view. However, various other structures, e.g.,
engine 104 and most of the chassis 102, are removed for visibility.
As this view illustrates, the control system 300 may include
independent linkage systems for each side of the mower 100, e.g.,
for each control lever 302 and its associated pump 110. While the
system 300 is illustrated in the figures as including dual
mechanisms to independently control the drive wheel 106 on each
side of the mower 100, control systems for alternate applications
may utilize a single linkage without departing from the scope of
the invention.
[0053] FIG. 7 is an enlarged view of a portion of the mower of FIG.
4. This view illustrates a lower portion of one side of the control
linkage system 300 that operatively connects one control link 312
(e.g., link 312b) to its respective pump 110 (e.g., pump 110b). As
shown in this view, a pivot link, e.g., bellcrank 316, may be
pivotally attached to the chassis 102 at a chassis pivot 318 for
pivoting about a horizontal transverse axis 320 (see FIG. 6). Each
bellcrank 316 may include a first arm defining a first end 322 that
is offset from the chassis pivot 318. The first arm of the
bellcrank may be pivotally connected to a proximal end of the
control link 312 at a control link pivot 324. The bellcrank 316 may
also include a second arm defining a second end 326 pivotally
connected to a first end 327 of a drive link 328 at a first drive
link pivot 330. A second end 329 of the drive link 328 may
pivotally connect to a distal end of the pump input member or arm
332 at a second drive link pivot 334. The input arm 332 may move,
e.g., pivot, about an input pivot 333 relative to a housing of the
pump, thereby repositioning an internal swashplate within the pump
to alter the flow of hydraulic fluid delivered to the respective
wheel motor 107 (see also FIG. 1). In the illustrated embodiment,
the drive link may be curvilinear in shape to better accommodate
the mower configuration. However, other shapes, e.g., straight, are
certainly possible without departing from the scope of the
invention.
[0054] The solid line representation of the drive link 328 and
bellcrank 316 in FIG. 7 represents the geometry of the system 300
when the drive control lever 302 is in the first or neutral
position (see solid line representation of the control lever 302 in
FIG. 5). Conversely, the broken line representation of the drive
link 328 and bellcrank 316 in FIG. 7 represents the geometry of the
system 300 when the drive control lever 302 is in the second or
engaged position (see broken line representation of the control
lever 302 in FIG. 5). Thus, movement of the control levers 302 may
vary a position of the respective pump input arm 332 relative to
the pump housing. For instance, as is evident in FIG. 7,
incremental movement of the drive control lever 302 from the first
or neutral position to the second or engaged position causes the
pump input arm 332 (to which the drive link 328 is attached) to
pivot, relative to the pump housing, from a first or pump neutral
position (wherein the pump input arm is approximately vertical,
e.g., about 12 o'clock in FIG. 7), to an adjustable second or
maximum position (wherein the pump input arm is rotated slightly
clockwise in FIG. 7, e.g., to about one o'clock as shown in broken
lines). This relationship between control levers 302 and their
respective input arms 332 exists regardless of whether the platform
is in (or is moving between) the first position, the second
position or any intermediate position.
[0055] FIG. 8 is a view similar to FIG. 7, but with the platform
112 shown at its second or lowest position (as opposed to the first
or highest position shown in FIG. 7) and the drive control lever
302/system 300 shown in the neutral position. The platform height
adjustment may be accommodated as described elsewhere herein, e.g.,
with the lift mechanism 220 illustrated in FIGS. 3A-3B. Once again,
as the platform 112 and deck 114 move from the elevation of FIG. 7
to the elevation of FIG. 8, movement occurs along the arc 255
defined by the distance 256 of each of the bellcranks 230 and 240
(see also FIG. 3A). Moreover, as the platform/cutting deck move,
each drive link 328 may pivot about the first drive link pivot 330
from the position shown in solid lines in FIG. 7 to the position
shown in FIG. 8.
[0056] In the embodiment illustrated in FIGS. 7 and 8, the drive
link 328 has an effective length 336 (e.g., linear distance
measured between the first and second drive link pivots 330 and
334) that is equal to the effective length 256 of the platform
bellcranks. Moreover, a line 257 (see FIG. 8) extending between
each platform chassis pivot 232 and its associated platform pivot
247 may be parallel to a line 258 extending between the first and
second drive link pivots 330 and 334.
[0057] Furthermore, as illustrated in FIG. 8, a linear distance 337
between the input pivot 333 and the second drive link pivot 334 may
be equal to a linear distance 338 between the chassis pivot 318 and
the first drive link pivot 330, while a line 260 extending between
the input pivot 333 and the second drive link pivot 334 may be
parallel to a line 262 extending between the chassis pivot 318 and
the first drive link pivot 330.
[0058] As a result of this geometry, the drive link 328 may
accommodate pivoting of the platform 112 without imparting any
unintended displacement to the input arm 332 of the pump. Thus, the
platform 112/cutting deck 114 may be moved to any available height
without altering the position of the pump input arm 332. The
linkage system may therefore maintain, as the platform 112 is moved
between its first and second positions, both the position of the
input member 332 relative to the drive unit 110, and a position of
the control link 312 (as well as the control lever 302) relative to
the chassis 102.
[0059] While the control system is shown only in the neutral
position in FIG. 8, the same result may occur regardless of the
position of the drive control lever 302. For instance, placement of
the drive control lever 302 in the second (e.g., forward) or
engaged position (broken lines in FIG. 5) with the platform 112 at
its lowest setting as shown in FIG. 8 would result in positioning
the pump input arm 332 in the same location as it is positioned
when the platform is at its highest setting (see broken line
rendering in FIG. 7). In fact, the platform 112 could even be
repositioned during operation (while the control handles remain in
a given position) without any effect on pump configuration/mower
speed.
[0060] In some embodiments, the motion control linkage system 300
may further include a velocity limiting mechanism, an exemplary
embodiment of which will now be described with reference to FIGS. 9
and 10. Generally speaking, the velocity limiting mechanism permits
the operator to limit or adjust a maximum potential forward
velocity of the mower (the speed resulting when the levers 302 are
resting against the forward stop bar 304) without varying the
engine throttle.
[0061] In the illustrated embodiment, the velocity limiting
mechanism is configured as a selectively pivotable forward stop bar
304 defining a stop surface against which the drive control levers
may rest when in the second or engaged position. When in a first or
maximum potential velocity position "A", the forward stop bar 304
is positioned at a first distance from the drive control lever 302
(when the latter is in the neutral position) as shown in FIG. 9. In
a second or reduced maximum potential velocity position "B", the
forward stop bar 304 is positioned at a second distance from the
drive control lever 302 that is less than the first distance as
shown in FIG. 10.
[0062] As a result, when the operator wants to reduce the potential
maximum speed of the mower (e.g., to conduct operator training or
to address cut quality under various mowing conditions) but still
wishes to maintain optimal engine speed and/or the comfort
associated with holding the drive control levers against the fixed
stop bar 304, the forward stop can be repositioned as shown in FIG.
10 (or repositioned to any intermediate position). Repositioning
the forward stop from position A of FIG. 9 to position B of FIG. 10
may, in one embodiment, reduce the maximum potential speed of the
mower (for a given throttle setting) from a first maximum vehicle
speed setting, e.g., about eight miles/hour, to a second or reduced
maximum vehicle speed setting, e.g., about four miles/hour.
[0063] In one embodiment, the forward stop bar 304 is pivotally
attached to the mower chassis 102 for pivoting about a transverse
pivot axis that is coincident with the pivot axis 307 (see FIG. 6)
of the drive control levers 302. As a result, the stop bar 304,
independent of its position, stays within the same arc of rotation
as that in which the levers 302 move. Accordingly, each drive
control lever 302 contacts the stop bar 304 at the same location
regardless of the stop bar position. By avoiding all but movement
about a common axis for both the drive control levers 302 and the
stop bar 304, comfortable and repeatable positioning of the drive
control levers relative to the stop bar is maintained.
[0064] While not illustrated herein, the stop bar 304 could be
split such that a separate stop bar is provided for each of the
drive control levers 302. Moreover, the mower 100 could also
include a rear stop bar (not shown) to adjust the maximum rearward
velocity of the mower (e.g., the maximum rearward velocity
resulting from pulling the drive control levers to a fully aft
position).
[0065] The velocity limiting mechanism may also include a lock
mechanism to secure the forward stop bar 304 in place. In one
embodiment, the forward stop bar 304 includes a bracket 340 that
sits along one or both sides of the chassis 102. The bracket may
define a slot 342 through which a clamp 344 passes and threads to
the chassis 102. By loosening the clamp 344, the forward stop bar
304 may pivot within the confines defined by the clamp sitting
within the slot 342. By tightening the clamp 344, the stop bar may
be locked in position A of FIG. 9, position B of FIG. 10, or any
intermediate position. The slot 342 may include detents or the like
to indicate discrete locations, or may permit generally infinite
positioning.
[0066] Embodiments of the instant application may therefore provide
a motion control system and vehicle incorporating the same. Control
systems configured in accordance with embodiments of the present
invention may include a linkage for accurately adjusting a
parameter (e.g., velocity) of the vehicle even as a geometric
relationship between an input (e.g., velocity control lever) and an
output (e.g., drive train) of the vehicle is modified. Other
embodiments may further address velocity limiting mechanisms,
illustrative embodiments of which are described herein, that may be
used in conjunction with, or independently of, the exemplary motion
control system.
[0067] Illustrative embodiments of this invention are discussed and
reference has been made to possible variations within the scope of
this invention. These and other variations, combinations, and
modifications in the invention will be apparent to those skilled in
the art without departing from the scope of the invention, and it
should be understood that this invention is not limited to the
illustrative embodiments set forth herein. Accordingly, the
invention is to be limited only by the claims provided below and
equivalents thereof.
* * * * *