Motor vehicles – Special driving device – Portable track
Reexamination Certificate
2000-01-18
2001-05-29
Olszewski, Robert P. (Department: 2167)
Motor vehicles
Special driving device
Portable track
C180S193000
Reexamination Certificate
active
06237706
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for adjusting the range of calibration of a vehicle suspension system with respect to comfort, control, and load capacity from a remote location on the vehicle, and in particular, to a method and apparatus for dynamically changing the motion ratio of the biasing/dampening mechanism relative to the suspension system.
BACKGROUND OF THE INVENTION
Numerous types of vehicles are used for traveling over a variety of surfaces. For example, all terrain vehicles and snowmobiles may be used to traverse smooth roads, small to medium bumps, very large bumps, and frozen or unfrozen terrain all in a single excursion. To obtain the optimum ride quality for each set of conditions, a different ratio of travel between the vehicle and the biasing mechanism on the suspension system is required. The ratio of shock absorber and/or spring displacement divided by the total vertical displacement of the suspension system relative to the vehicle chassis at a selected location (hereinafter referred to as motion ratio) for optimum ride control varies greatly depending on the terrain conditions and speed at which the vehicle is traveling.
The importance of a proper motion ratio can be illustrated by the snowmobile
10
of FIG.
1
. The snowmobile
10
has a body frame or chassis
12
that mounts a seat
14
on an upper side thereof Seated on the snowmobile seat
14
, the driver manually steers the vehicle
10
by a handlebar assembly
18
that is secured to a steering shaft
20
that extends through a compartment
22
for the internal combustion engine
24
. The steering shaft
20
is operatively connected to a pair of steerable skis
28
through a steerable linkage preferably arranged so that the inside cornering ski
28
turns at a greater angle than the outside ski
28
so as to provide comfortable steering.
An endless track
16
driven by a main drive wheel
40
operatively connected to the internal combustion engine
24
rotates around a suspension system
26
. The suspension system
26
includes a slide rail
30
connected to the chassis
12
by a front suspension arm
32
and a rear suspension arm
34
. At least one biasing/dampening mechanism
36
is provided for biasing the slide rail
30
away from the chassis
12
. In the embodiment illustrated in
FIG. 1
, lower end
38
of the rear biasing/dampening mechanism
36
, is pivotally connected to the slide rail
30
through a mechanical adjustment mechanism (not shown) to provide for adjusting the location of the lower end
38
over a distance, and thus, adjusting the motion ratio. In one embodiment, adjustment of the lower end
38
is made within a slot
42
.
There is no easy way to adjust the motion ratio for a specific terrain without stopping the vehicle and manually making the adjustment. For example, in the context of the snowmobile of
FIG. 1
, the driver may move from a smooth, groomed trail to a very rough terrain. If the suspension has been delivering optimum ride quality on the smooth trail, the motion ratio may need to be increased to provide optimum ride quality on the rough terrain. For example, the vehicle will periodically bottom out at lower speeds than would otherwise be able to be maintained with a proper motion ratio. The driver is faced with a choice of either stopping the snowmobile and crawling under the chassis to make the adjustment or enduring the consequences of a less than optimum motion ratio.
A smooth and controlled ride over varied terrain is one of the most important handling qualities of snowmobiles, as well as a variety of other recreational vehicles. The suspending forces of the vehicle suspension system with regard to any bumps is directly affected by the speed of the shock absorber as well as the displacement of the biasing/dampening mechanism. Both of these factors are controlled by the motion ratio. The higher the motion ratio, the greater the resistance of the suspension system to vertical displacement during compression travel. The lower the motion ratio, the less resistance provided by the suspension system to vertical displacement on compression travel. All other parameters remaining the same, a motion ratio that is high enough to withstand bottoming of the chassis against the suspension system in rough terrain with large bumps will also deliver a rough, less comfortable ride on smoother terrain. In the opposite conditions, a motion ratio low enough to deliver a comfortable ride on smooth terrain will periodically bottom out on rough terrain.
U.S. Pat. No. 3,115,945 illustrates a chassis support apparatus having a pivotally mounted cushion cylinders that may be adjusted more and less vertical to adjust for heavy or light loads. The cushion cylinders are pivotally attached to a moveable pivot block that is engaged with a threaded transverse member rigidly mounted to the frame. Consequently, the adjustment mechanism is located on the frame.
SUMMARY OF THE INVENTION
The present invention relates to a method and apparatus for increasing the range of a suspension system's ride calibration with respect to comfort, control, and load capacity from a remote location on the vehicle through changing the motion ratio of one or more components of the vehicle suspension system.
In one embodiment, the present method and apparatus provide a change in the motion ratio of a biasing/dampening mechanism to the vehicle on a suspension system under the vehicle. Altering the motion ratio changes the speed and/or displacement of the biasing/dampening mechanism, and hence, altering the stiffness with which the suspension system isolates the vehicle from the terrain.
The vehicle suspension system with a variable geometry comprises a moveable suspension arm pivotally attached to a vehicle chassis. A biasing/dampening mechanism is operatively attached to the vehicle chassis at a first end. An actuator mechanism operatively connects the second end of the biasing/dampening mechanism to the moveable suspension arm. The actuator mechanism has means for moving the second end along at least one axis when the vehicle is in a static or dynamic mode to increase or decrease the motion ratio of the biasing/dampening mechanism relative to the moveable suspension arm. A control mechanism is provided for activating the actuator mechanism. The actuator mechanism is capable of increasing or decreasing the motion ratio of the biasing/dampening mechanism relative to the total displacement of the suspension system relative to the chassis.
In one embodiment, the actuator mechanism is pivotally connected to the moveable suspension arm. The actuator mechanism may be operatively connected to the second end of the biasing/dampening mechanism by a rocker arm and a pull rod. Consequently, it is possible to indirectly move the location of the second end of the biasing/dampening mechanism to the moveable suspension arm. The biasing/dampening mechanism may be a shock absorber and/or spring.
A sensor may be provided for sensing the location of the second end of the biasing/dampening mechanism when the vehicle is in the static or dynamic mode. A display is preferably provided for indicating the location of the second end of the biasing/dampening mechanism.
The actuator mechanism may be a hydraulic ram or a motor driven linkage mechanism. In one embodiment, the actuator mechanism comprises a mechanical linkage for displacing the second end of the biasing/dampening mechanism and an electric motor coupled to the mechanical linkage.
The electric motor may be connected in series to an electrical system on the vehicle. In one embodiment, a first power converter converts alternating current from the electric power source on the vehicle to direct current prior to the electric motor. A second power converter converts direct current from the motor to alternating current. The alternating current from the second power converter is directed back to the electrical system on the vehicle.
In one embodiment, the suspension system with a variable geometry suspends an endless track beneath a tracked
Karpik David J.
Karpik Gerard J.
Lehman Michael A.
Miers Scott A.
Cuff Michael
Faegre & Benson LLP
Fast Action Support Team, Inc.
Olszewski Robert P.
LandOfFree
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