Abstract:
A vehicle suspension system with a variable geometry. A moveable suspension arm is 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 a mechanism 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 or displacement of the biasing/dampening mechanism to the total displacement of the suspension system relative to the vehicle chassis. A control mechanism is provided for activating the actuator mechanism.

Description:
This is a continuation of prior application Ser. No. 08/853,442, filed May 6, 1997 is now U.S. Pat. No. 6,032,752. 
    
    
     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&#39;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 vehicle. The suspension assembly has an elongated slide rail with a bottom track engaging portion defining a longitudinal axis. At least one suspension arm pivotally connects the vehicle chassis with the slide rail. A biasing/dampening mechanism urges the slide rail away from the vehicle chassis. The biasing/dampening mechanism has a first end operatively connected to the vehicle chassis at a first location and a second end operatively connected to the slide rail at a second location. An actuator mechanism operatively connects the second end of the biasing/dampening mechanism to the slide rail. The actuator mechanism includes 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 displacement of the biasing/dampening mechanism relative to the displacement of the slide rail. A control mechanism is provided for activating the actuator mechanism. The control mechanism may be a simple switch or a programmable logic controller activated by the rider. 
     The present invention is also directed to a method for adjusting the geometry of a suspension system on a vehicle. A moveable suspension arm is pivotally attached to a vehicle chassis. A biasing force is applied between the chassis and a first location on the moveable suspension arm using a biasing/dampening mechanism. A control mechanism signals the activation of an actuator mechanism when the vehicle is in a static or dynamic mode, whereby the location where the biasing force engages with the moveable suspension arm is displaced to a second location and the motion ratio of the biasing force to the moveable suspension arm is increased or decreased. 
     The vehicle may be a snowmobile, an all-terrain vehicle or a motor cycle. 
     The present invention is also directed to a method for powering an accessory using an electric power source in a vehicle&#39;s electric system. Unregulated alternating current up to a selected voltage level from the electric power source on the vehicle is converted to direct current. The direct current is directed to the accessory in series with the electric power source on the vehicle. Direct current from the accessory is converted to alternating current. The alternating current from the accessory is directed to the electric system on the vehicle. The accessory may be an electric motor, fuel injection system or a variety of other components. 
     Motion Ratio refers to the ratio of the displacement of a biasing/dampening mechanism (shock, damper and/or spring) divided by the total displacement of the suspension system relative to the vehicle chassis at a selected location. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a side view of a prior art suspension system for a snowmobile. 
     FIG. 2 is a perspective view of an exemplary suspension system according to the present invention. 
     FIG. 3 is a side view of an alternate snowmobile suspension system according to the present invention. 
     FIG. 4 is a schematic illustration of a second alternative snowmobile suspension system according to the present invention. 
     FIG. 5 is a schematic illustration of a suspension system according to the present invention for use on a motorcycle or bicycle. 
     FIG. 6 is a perspective view of a suspension system according to the present invention for use on an all terrain vehicle. 
     FIG. 7 is a schematic illustration of the control mechanism for the present suspension system. 
     FIG. 8 is an idealized illustration of the motion ratio of the present suspension system. 
     FIG. 9 is an idealized illustration of the motion ratio of a suspension system in which the biasing/dampening mechanism is displaced along the vehicle chassis. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 2 is a perspective view of an exemplary suspension system  50  according to the present invention. Although the suspension system  50  of FIG. 2 is configured for use on a snowmobile, it will be understood that the present invention may be utilized on a wide variety of recreational vehicles and that the embodiment of FIG. 2 is for illustration purposes only. 
     The suspension system  50  generally includes a pair of suspension arms  52  connected to a vehicle chassis (not shown) at an upper end  54 . The upper end  54  preferably is pivotally attached either directly to the vehicle chassis or through additional linkage. The lower end of the suspension arms  52  are engaged with a slide rail  56  through a slide block linkage mechanism  58 . Various slide block linkage mechanisms are further discussed in U.S. Pat. Nos. 5,370,198 (Karpik) and U.S. Pat. No. 5,265,692 (Mallette). 
     The slide rail  56  is biased away from the upper end  54  of the suspension arms  52  by a biasing/dampening mechanism  60 , The biasing/dampening mechanism  60  is pivotally mounted at a pivot joint  66  to the upper end  54 . The lower end of the biasing/dampening mechanism  60  is pivotally mounted at a pivot joint  68  attached to an actuator arm  70 . 
     The biasing/dampening mechanism in the present embodiment includes a shock absorber  62  and a spring  64 , although either component may be used without the other to form the biasing/dampening mechanism. Each component behaves differently to displacement. The spring  64  is displacement sensitive. For example, a spring may provide resistance of 100 lbs. for each inch of displacement. By increasing or decreasing the motion ratio of the spring relative to the suspension system, the amount the spring is displaced for a given displacement of the suspension system  50  may be adjusted. 
     The shock absorber  62  is primarily speed sensitive. That is, the resistance provided by the shock absorber increases with the speed at which the shock absorber is displaced. In the case of fluid-based shock absorbers, drag of the fluid is proportional to velocity of the fluid squared so that the force versus velocity relationship of the shock absorber is parabolic. Doubling the displacement speed quadruples the resistance of the shock absorber. Shock absorbers tend to be more effective (provide greater resistance) at higher speeds. At a high motion ratio, the shock absorber is displaced over a greater length for a given vertical compression of the suspension system and hence its operational speed is increased with a corresponding increase in resistance. Similarly, at a lower motion ratio, the shock absorber is displaced over a shorter length for the same vertical displacement of the suspension system, and hence its operational speed is decreased with a corresponding decrease in resistance. Therefore, the present suspension system  50  with variable geometry is capable of adjusting both the speed of the shock absorber and the displacement of the spring. 
     A motor  72  is located along one side of the slide rail  56 . The motor  72  is connected to a bevel gear drive  74  by a drive shaft  76 . The bevel gear drive  74  is operatively connected to a threaded member  78  which engages the mating threaded portion of the actuator arm  70 . Rotation of the motor  72  causes the actuator arm  70  to move along the axis B. The actuator arm  70  and/or housing  90  are preferably beveled at their respective intersection locations to minimize accumulation of ice or debris. The motor preferably provides about 7.1 newton-meters to about 10.5 newton-meters of torque at 10 revolutions per minute, when the specified voltage and current are supplied. A suitable motor is a Bosch part no. 9000016040 available from Chief Enterprises located in Elmhurst, Ill. A variety of actuator mechanisms, such as hydraulic or pneumatic cylinders, may alternatively be used. Various actuators are disclosed in U.S. Pat. Nos. 4,756,517 (Kakimoto), 4,895,383 (Abe et al.), U.S. Pat. No. 4,911,466 (Blair), and U.S. Pat. No. 5,094,472 (Oyama et al.). 
     Movement of the actuator arm  70  along the axis B changes the motion ratio of the suspension system  50 . When the actuator arm  70  is in its most retracted position (closest to the bevel gear drive  74 ), the suspension system  50  is in a low motion ratio or soft configuration  80 . The biasing/dampening mechanism  60  will be at its lowest speed and displacement in the low motion ratio configuration  80 . As the actuator arm  70  extends away from the bevel gear drive  74 , the suspension system  50  moves through an intermediate motion ratio configuration  82  to a high motion ratio configuration  84 . In the high motion configuration  84 , the biasing/dampening mechanism is in its maximum speed and displacement. As discussed above, the configuration  84  provides the suspension system  50  with a high motion ratio when subjected to an input force C. The configuration  80  provides less resistance to vertical displacement of the suspension system  50  (low motion ratio) to the input force C. 
     Moving the lower end of the biasing/dampening mechanism  60  provides a greater change of mechanical advantage to the suspension system  50  than would be realized if the upper end were moved. That is, the greatest change in the motion ratio is effectuated by locating the moving end of the biasing/dampening mechanism on the slide rail, swing arm or other moving member. For example, the present actuator arm  70  has a range of motion of about 33 mm (1.3 inches), corresponding to a change of 7.3 cm (2.87 inches) in the vertical travel of the slide rail  56 . 
     The bevel gear drive  74  preferably includes an indicator, such as a magnet  86 , that is detectable by a detector  88  mounted to a housing  90  containing the bevel gear drive  74  and threaded member  78 . Control electronics  92  (see FIG. 7) is preferably a programmable logic controller for monitoring the detector  88  and counting the rotations of the bevel gear drive  74  so that the position of the actuator arm  70  can be displayed to the driver via a display  94  to the rider. A simple switch may be used in place of the control electronics  92 . A linear variable displacement transducer or a variety of other device may be used to sense the position of the actuator arm  70 . 
     In the event the control electronics  92  does not receive a pulse from the detector  88  for some period of time during which the motor  72  has been activated, the control electronics  92  assumes that the actuator arm  70  has reached a limit to its physical range of motion and subsequently terminates the power to the motor  72 . Similarly, if movement of the actuator arm  70  is blocked by ice or another obstruction, the control electronics  92  will sense the lack of movement and signal an error to the rider via the display device  94  and terminate the power to the motor  72 . Non-volatile memory is provided to store the last position until the vehicle is started again. 
     FIG. 3 is a schematic illustration of an alternate snowmobile suspension system  50 ′ according to the present invention. Suspension arm  52 ′ pivotally connects slide rail  56 ′ to a rocker arm  100 . The top edge of the rocker arm  100  is pivotally connected to a biasing/dampening mechanism  60 ′. The biasing/dampening mechanism  60 ′ may be a shock absorber  62 ′ and/or a spring  64 ′. The other end of the biasing/dampening mechanism  60 ′ is pivotally mounted to the chassis (not shown) through another rocker arm of the snowmobile. The lower end of the rocker arm  100  is pivotally mounted to a pull rod  102 . The other end of the pull rod  102  is pivotally engaged with the actuator arm  70 ′ on the actuator  72 ′, such as the motor described in FIG.  2 . The actuator arm  70 ′ moves along an axis B so as to displace the pull rod  102 ′. Extending the actuator arm  70 ′ causes the pull rod  102 ′ to rotate the rocker arm  100  in a counterclockwise direction. Retraction of the actuator arm  70 ′ rotates the rocker arm  100  in a clockwise direction. This rotational variation increases or decrease the speed and displacement of the biasing/dampening mechanism  60 ′. Increasing the speed and displacement of the biasing/dampening mechanism  60 ′ corresponds to a higher motion ratio configuration and a stiffening of the suspension system  50 ′. Similarly, retraction of the actuator arm  70 ′ causes the rocker arm  100  to rotate in a clockwise direction and the speed and displacement of the biasing/dampening mechanism  60 ′ to be increased. Decreasing the speed and displacement of the biasing/dampening mechanism  60 ′ corresponds to a lower motion ratio and a softer ride on the vehicle. 
     FIG. 4 is a schematic illustration of an alternate snowmobile suspension system  50 ″ according to the present invention. A biasing/dampening mechanism  60 ″ is attached either directly or via a linkage system to a slide rail  56 ″ at one end and an actuator arm  70 ″ at the other end. The actuator  72 ″ is preferably rigidly attached to the suspension arm  74 ″. The actuator arm extends and retracts along an axis B″ in response to the control electronics  92 . When the actuator arm  70 ″ is moved to the retracted position toward the actuator  72 ′, the speed and displacement of the biasing/dampening mechanism  60 ′ is reduced, resulting in a lower motion ratio. Correspondingly, as the actuator arm  70 ″ is extended away from the actuator  72 ″, the speed and displacement of the biasing/dampening mechanism  60 ″ is increased, corresponding to a higher motion ratio. 
     FIG. 5 is a schematic illustration of a suspension system  150  according to the present invention for use on a motorcycle or bicycle. The rear wheel  152  of the motorcycle is pivotally mounted to the frame  154  by frame member or swing arm  156 . The frame member  156  is attached to the frame  150  at pivoting joint  158 . The frame member  156  is biased downward by a biasing/dampening mechanism  160  which is pivotally attached to an upper portion of the frame at a location  162 . The lower portion of the biasing/dampening mechanism  160  is pivotally attached to an actuator arm  164  that can be displaced along an axis  166  by an actuator  168 . In the embodiment of FIG. 5, the actuator  168  is pivotally mounted to the frame member  156  at a location  170 . The position of the actuator  168  relative to the frame  154  is maintained by linkage  172 . Locating the actuator  168  on the swing arm  156  provides a greater variation in the mechanical advantage and greater change in the motion ratio than locating it proximate the location  162 . When the actuator arm  164  is retracted, the speed and displacement of the biasing/dampening mechanism  160  is reduced, resulting in a lower motion ratio and a softer ride. Correspondingly, as the actuator arm  164  is extended, the speed and displacement of the biasing/dampening mechanism  160  is increased, resulting in a higher motion ratio and a stiffer ride. 
     FIG. 6 is a perspective view of an exemplary suspension system  180  suitable for use in an all terrain vehicle (not shown). A swing arm or suspension member  182  is biased downwards away from the vehicle chassis  186  by a biasing/dampening mechanism  184 . The biasing/dampening mechanism  184  is pivotally mounted to the chassis  186  at one end and to an actuator arm  188  on an actuator  192  at the other end. The actuator  192  is preferably rigidly mounted to the swing arm  182 . The actuator arm  188  may be displaced along an axis  190  so as to change the speed and displacement of the biasing/dampening mechanism  184 . Locating the actuator  192  on the swing arm  182  provides a greater change in the mechanical advantage and a greater change in the motion ratio than locating it proximate the location  186 . 
     The present suspension system requires considerable power to alter the motion ratio during operation of the vehicle. While it would be possible to design an electric power source or other power source on a recreational vehicle with adequate capacity to operate the present suspension system or other components requiring considerable power such as a fuel injection system without a battery, retrofitting the present suspension system to an existing vehicle has proven somewhat problematic. For example, snowmobiles typically utilize a magneto for generating electric power for the lights, heaters, and ignition system. The magneto generates between about 20 volts AC during idling to 80 volts AC at high RPMs at about 3-10 amps. 
     FIG. 7 is a schematic illustration of one approach to maximizing the power output from the magneto on an existing recreational vehicle. Rather than powering the motor  72  of the present vehicle suspension system  50  in parallel with the heaters  202  and lights  204  of the vehicle, motor  72  is arranged in series upstream of the electrical components on the vehicle to receive raw power directly from the magneto  206  before power is provided to the other electrical components on the vehicle. 
     When the rider engages the switch  96 , the controller  92  activates a toggle switch  208  to divert alternating current directly from the recreational vehicle&#39;s magneto/electric generator  206 . The alternating current is converted to DC current in an A-to-D converter  210 . The direct current is routed through a directional relay  213  in parallel with a voltage regulator  211  to the motor  72  to operate the motor at about 18 V DC . The relay  213  switches the motor  72  in and out with the standard electrical system on the vehicle. A capacitor in the range of about 1500 μF is provided in the motor to reduce voltage fluctuations. The remaining current is then converted back to AC by a D-to-A converter  212  and directed to supply the rest of the vehicle&#39;s electrical requirements. By prioritizing power distribution, 18 V DC  at 8 amps is available to the motor  72  from a system that typically provide only 12 V AC . The present method and apparatus for diverting power directly from the vehicle&#39;s electrical system makes it possible to power other components, such as fuel injection systems using existing power sources. 
     The motor  72  drives the actuator arm in the chosen direction to vary the motion ratio of the suspension system. The controller  92  continues to direct power to the motor  72  until the detector  88  indicates the desired motion ratio has been attained or the actuator arm  70  has stopped moving for some period of time. When the controller  92  deactivates the motor  72 , power from the magneto  206  is redirected to the recreational vehicle&#39;s normal electrical system by switch  208 . 
     EXAMPLE 
     FIGS. 8 and 9 show idealized suspension systems to schematically illustrate the advantage of locating the actuator on the moving frame member or swing arm, rather than on the fixed frame or chassis of the vehicle. For purposes of the illustration, the swing arms had a length of 201.5 mm. The swing arm  250  is permitted to pivot about location  252  through an arc of 45°; 22.5° above and below horizontal, corresponding to a suspension travel distance of 154.2 mm. The active end of the biasing/dampening mechanism  254  was displaced 33 mm from vertical. For purposes of this analysis, the active end of the biasing/dampening mechanism is at location zero when in the vertical configuration and at 33 mm when fully displaced. Motion ratio was defined as the displacement of the biasing/dampening mechanism/ total displacement of the suspension system. 
     FIG. 8 is a schematic illustration of an exemplary motion ratio for a suspension system according to the present invention. The displacement of the biasing/dampening mechanism takes place along segment  256  of the moving portion of the suspension system, in this case, along the swing arm  250 . When the biasing/dampening mechanism is in a vertical configuration, the compressed length  254 A of the biasing/dampening mechanism is about 139.26 mm and the extended length  254 B of the biasing/dampening mechanism is about  240 . 38  mm. At a displacement of 33 mm from vertical, the compressed length  254 C of the biasing/dampening mechanism is about 130.25 mm and the extended length  254 D of the biasing/dampening mechanism is about 254.84 mm. 
     The motion ratio for the vertical configuration (soft ride) was calculated at about 65.5 ((240.38−139.26)/154.2=65.5). The motion ratio for the displaced configuration (firm ride) was calculated at about 80.7 ((254.84−130.25)/154.2=80.7). The percentage change of the motion ratio as a result of 33 mm of displacement along the swing arm  250  was about 23%. 
     FIG. 9 is a schematic illustration of a suspension system in which the biasing/dampening mechanism  260  is displaced along segment  262  on the chassis or frame of the vehicle, rather than on the swing arm  250 . When in a vertical configuration, the compressed length  260 A of the biasing/dampening mechanism is about 128.46 mm and the extended length  260 B is about 254.84 mm. At a displacement of 33 mm from vertical, the compressed length  260 C of the biasing/dampening mechanism is about 132.63 mm and the extended length  254 D is about 256.97 mm. 
     The motion ratio for the vertical or firm configuration was calculated at about 81.9 ((254.84−128.46)/154.2=81.9). The motion ratio for the displaced or soft configuration was calculated at about 80.8 ((256.97−132.63)/154.2=80.8). The percentage change of the motion ratio as a result of 33 mm of displacement along the chassis was about 1.3%. Therefore, in spite of the risk of environmental contamination or damage, there is a significant advantage in locating the mechanism for displacing the biasing/dampening mechanism along the moving portion of the suspension system, such as on the swing arm. 
     Patents and patent applications disclosed herein, including those cited in the background of the invention, are hereby incorporated by reference. Other embodiments of the invention are possible. It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.