Abstract:
A deployable running board mounted on an automotive vehicle to be laterally extendable so as to engage the ground during a rollover event to increase the rollover resistance of the vehicle. The running boards are connected to a pair of deployment members spaced longitudinally on the vehicle to provide a rapid extension of the running board. Each deployment member includes a telescopic piston that is slidably mounted within a cylinder and that compresses a spring between the piston and the cylinder. A latching mechanism secures the piston in a retracted stated until a rollover event is detected. Releasing the latching mechanism allows the piston to telescope laterally to move the attached running board outwardly of the vehicle to provide a pivot point that increases the static stability factor of the vehicle. The engagement of the extended running board also provides a resistance to the continued motion of the vehicle.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates generally to an extendable running board for use on an automotive vehicle and, more particularly, to a running board that is mounted for outward projection in the event of a rollover of the vehicle to increase rollover resistance by increasing the tipped-over angle at the unstable equilibrium. 
       BACKGROUND OF THE INVENTION 
       [0002]    Running boards are available on many automotive vehicles, such as pick-up trucks, and sport utility vehicles, to provide an easy ingress and egress to the vehicles. In some vehicles the running boards are fixed to the frame of the vehicle and are not intended to move in any direction. In other vehicles, the running board is movably mounted for selective positioning for the convenience of the user of the running board. For example a powered movement of the running boards is disclosed in U.S. Pat. No. 6,325,397, issued to David M. Pascoe, et al on Dec. 4, 2001. In this Pascoe patent, the running board is mounted on parallel linkages, which are coupled to an electric motor to effect a powered pivotal movement of the running board between a stored position and a deployed position. Other movable running boards are mechanically moved, such as is disclosed in U.S. Pat. No. 5,697,626, issued to Patrick K. McDonald, et al on Dec. 16, 1997, in which the running board is pivotally supported on the frame of the vehicle and vertically movable by a bell crank that pivotally moves the step portion of the running board. Such movable running boards are utilized solely for the purpose of providing convenient access between the ground and the passenger compartment of the vehicle. 
         [0003]    The static stability factor (SSF) of a vehicle is a parameter used by the NHTSA to determine the rollover propensity of an automotive vehicle. A typical passenger car exhibits an SSF in the range of 1.3 to 1.5 while larger vehicles, such as the SUV&#39;s may have an SSF value in the range of 1.0 to 1.3, due primarily to the higher location of the center of gravity. The SSF factor is calculated as half the track width divided by the height to the center of gravity of the vehicle. The static stability factor also reflects the tilt table ratio and the centrifugal acceleration per gravity of the vehicle required to pass the point of unstable static equilibrium. Therefore, an increase in the SSF would indicate an increase in the roll angle at which the vehicle would become unstable and roll over to the side of the vehicle. If the effects of the suspension of the vehicle were ignored, passenger cars can be rolled statically to an angle of typically up to 52.4 to 56.3 degrees, or be subject to static lateral accelerations up to 1.3 to 1.5 times the force of gravity before experiencing a rollover event. Pick-up trucks and SUV&#39;s have a higher center of gravity resulting in a roll angle of typically about 45 to 52.4 degrees before experiencing a rollover event. When a vehicle is swerved onto gravel or earth during a potential rollover event, an increase in the resistance to the vehicle&#39;s speed, roll, yawing and sliding would shorten the time needed to bring the vehicle under control and stability. 
         [0004]    In U.S. Pat. No. 1,231,531 granted on Jun. 26, 1917, to E. C. Shilling an automotive vehicle is equipped with a tilt prevention apparatus that is manually operated by pulling a lever to activate the device carried on the front and rear bumpers of the vehicle. The framework slides by gravity to the left or to the right of the vehicle to engage the ground in the event the vehicle goes into a ditch or the like. Similarly, U.S. Pat. No. 1,932,031, issued to S. Bellantese on Oct. 24, 1933, the vehicle carries a laterally shiftable apparatus that is mounted to the frame under the vehicle. The apparatus is activated directly by centrifugal force exerted while driving on a curve which overcomes a set of springs retaining the apparatus in a central position. 
         [0005]    In U.S. Pat. No. 5,931,499, granted on Aug. 3, 1999, to D. R. Sutherland, two pyrotechnically activated roll protection devices are disclosed. In one embodiment, laterally extending stabilizer beams are activated by a cylinder/piston with a pyrotechnic charge encased inside the wheel axle shafts. The second embodiment utilizes two pivoted beams attached to the vehicle body frame on each side to rotate about their vertical axes to attain laterally extending positions to prevent roll. Utilizing pyrotechnic charges is a costly design and packaging the cylinder/piston mechanism with squibs would be a significant challenge. Several embodiments of a rollover prevention device for trucks are disclosed in U.S. Pat. No. 6,588,799, granted to A. Sanchez on Jul. 8, 2003. In one embodiment, a laterally extendable arm slides by gravity until the ball on the end of the arm contacts the ground. In another embodiment, a vertically attached gear arm is pivoted at the top to a hollow arm. When the vehicle starts to roll, the hollow arm swings while engaging the gears and gets locked to prevent the vehicle from rolling. In still another embodiment, a sensor activates a vertically mounted piston mechanism that is fixed to the suspension system. The upper and lower pistons are driven by compressed air when roll is sensed to drive the lower piston to engage the ground and the upper piston to push the vehicle body back to a level position. 
         [0006]    An inertia-based sensor is disclosed in U.S. Pat. No. 5,684,456, granted to Joachim Walter on Nov. 4, 1997, in which a cube-shaped weight is balanced by flexible arms and two extension measurement elements. The measuring element produces an electrical quantity such as a change in resistance or voltage. An electrical circuit would then be able to detect the roll and activate a remote device to prevent the roll. In U.S. Pat. No. 6,202,488, issued on Mar. 20, 2001, to S. M. Cash, an optical sensor based on inertia is disclosed. Such a sensor could be connected to an electronic control module to activate safety devices such as seatbelts, air bags in the event of a rollover, which is defined as being when the vehicle has rolled more than 75 degrees. Another inertia-based sensor is disclosed in U.S. Pat. No. 5,744,872, granted on Apr. 28, 1998, to Gasper Cairo in which a steel ball is mounted in a cup to generate an electrical signal in conjunction with an opaque projector associated with the movement of the ball. 
         [0007]    It would be desirable to provide an apparatus that is operable to increase resistance of an automotive vehicle in conjunction with a deployment of the running boards mounted on the vehicle. It would also be desirable to provide a spring-loaded telescopic mechanism that would be operable to deploy the running boards into a position to increase resistance to rollovers. 
       SUMMARY OF THE INVENTION 
       [0008]    It is an object of this invention to overcome the aforementioned disadvantages of the known prior art by providing a deployable running board that can be positioned to increase the resistance of an automotive vehicle to a rollover. 
         [0009]    It is another object of this invention to provide a spring-loaded deployment apparatus for laterally moving a running board mounted on a vehicle into a ground-engaging position to increase the resistance of the vehicle to rollover. 
         [0010]    It is still another object of this invention to provide a multi-functional apparatus for an automotive vehicle that can be deployed in a rollover event to increase the resistance of the vehicle to rolling over. 
         [0011]    It is a feature of this invention to provide an extendable running board apparatus that can be positioned for engagement with the ground as the vehicle starts to roll over to increase the roll angle at which the vehicle becomes unstable. 
         [0012]    It is an advantage of this invention that the extension of the running board laterally from the vehicle provides a pivot point for the vehicle during a rollover event that increases the angle at which the vehicle rolls over. 
         [0013]    It is another advantage of this invention that the effective static stability factor of a vehicle in increased by the lateral extension of the running board. 
         [0014]    It is another feature of this invention to provide a spring-loaded deployment apparatus that will rapidly extend the position of a vehicle&#39;s running board laterally in the event of a rollover event. 
         [0015]    It is still another advantage of this invention that the running boards retain their normal position to provide the primary function of assisting access into the passenger compartment of the vehicle, except upon the occurrence of a rollover event. 
         [0016]    It is yet another object of this invention to provide a deployable structure that can engage the ground in the early stages of a rollover event to provide resistance to the motion of the vehicle, including forward motion. 
         [0017]    It is another feature of this invention that the engagement of a deployment running board with the surface of the ground increases resistance to the velocity of the vehicle, as well as yawing and sliding motions. 
         [0018]    It is still another advantage of this invention that the deployment of the running board to engage the surface of the ground will help stabilize the vehicle before becoming unstable during a rollover event. 
         [0019]    It is yet another advantage of this invention that the running board deployment apparatus can be re-set to re-position the vehicle running boards to their normal position after being extended laterally to increase rollover resistance for the vehicle, in the case when the rollover was prevented and the parts were not damaged. 
         [0020]    It is still another feature of this invention that deployment apparatus can be positioned to extend the running board horizontally or angularly toward the ground. 
         [0021]    It is yet another feature of this invention that the deployment apparatus is formed of a telescopic piston mounted in a cylinder to be extendable therefrom by a spring compressed between the piston and the cylinder. 
         [0022]    It is a further advantage of this invention that the telescopic piston is latched into a retracted position corresponding to the normal position of the running board which is connected to the telescopic piston. 
         [0023]    It is a further feature of this invention that the latching mechanism is associated with an actuation device to trigger the release of the telescopic piston when a rollover event is detected. 
         [0024]    It is still a further feature of this invention that the roll angle at which a vehicle becomes unstable can be increased from approximately 50 degrees to greater than 70 degrees. 
         [0025]    It is still a further advantage of this invention that the lateral extension of the running board into engagement with the ground provides an additional resistance to motion to reduce speed, yawing and sliding. 
         [0026]    It is yet a further feature of this invention that the deployment apparatus can be activated by a mechanical apparatus, as well as an electronic apparatus. 
         [0027]    It is another feature of this invention that the latching mechanism includes two pairs of interacting pivoting members to control the release of the telescopic piston from the cylinder in which the telescopic piston is retracted. 
         [0028]    It is another advantage of this invention that the first pair of pivoted members is operable to prevent the second pair of pivoted members from moving to affect the release of the telescopic piston. 
         [0029]    It is still another feature of this invention that the telescopic piston is formed with latch members that project through openings in the back plate of the cylinder housing the telescopic piston to engage the latching mechanism. 
         [0030]    It is a further object of this invention to provide deployable running board that is laterally extendable to increase rollover resistance of a vehicle that is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple and effective in use. 
         [0031]    These and other objects, features and advantages are accomplished according to the instant invention by providing a deployable running board mounted on an automotive vehicle to be laterally extendable so as to engage the ground during a rollover event to increase the rollover resistance of the vehicle. The running boards are connected to a pair of deployment members spaced longitudinally on the vehicle to provide a rapid extension of the running board. Each deployment member includes a telescopic piston that is slidably mounted within a cylinder and that compresses a spring between the piston and the cylinder. A latching mechanism secures, the piston in a retracted stated until a rollover event is detected. Releasing the latching mechanism allows the piston to telescope laterally to move the attached running board outwardly of the vehicle to provide a pivot point that increases the static stability factor of the vehicle. The engagement of the extended running board also provides a resistance to the continued motion of the vehicle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]    The advantages of this invention will become apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein: 
           [0033]      FIG. 1  is a partial rear elevational view of an automotive vehicle having a laterally extendable running board coupled to a deployment apparatus according to the principles of the instant invention, the rear tire being broken away to better view the apparatus located between the front and rear tires, the laterally extended position of the running board being shown in phantom; 
           [0034]      FIG. 2  is a partial rear elevational view of an automotive vehicle having a second embodiment of an extendable running board incorporating the principles of the instant invention, the laterally extended position of the running board being shown in phantom; 
           [0035]      FIG. 3  is a schematic perspective view of the frame of the vehicle having a running board incorporating the principles of the instant invention supported thereon; 
           [0036]      FIG. 4  is a schematic perspective view of the vehicle frame depicted in  FIG. 3 , but showing the relative extended position of a first embodiment of the laterally extendable running board mounted on the left side of the frame; 
           [0037]      FIG. 5  is a schematic perspective view of the vehicle frame depicted in  FIG. 3 , but showing a second embodiment of the extendable running board, the left running board being shown in the extended position; 
           [0038]      FIG. 6  is a schematic perspective view of the vehicle frame similar to that of  FIG. 3 , but depicted a third running board embodiment; 
           [0039]      FIG. 7  is a schematic perspective view of the vehicle frame of  FIG. 6  showing the left running board being laterally extended; 
           [0040]      FIG. 8  is a diagrammatic rear elevational view of an automotive vehicle, the center of gravity being depicted by the circled “X”; 
           [0041]      FIG. 9  is a diagrammatic rear elevational view of the prior art vehicle showing the maximum roll angle before the vehicle becomes unstable and rolls over on its side; 
           [0042]      FIG. 10  is a diagrammatic rear elevational view of a vehicle having a deployable running board incorporating the principles of the instant invention, the running board being depicted in a laterally extended position and engaging the surface of the ground; 
           [0043]      FIG. 11  is a diagrammatic rear elevational view of the vehicle depicted in  FIG. 10  showing the maximum roll angle before the vehicle becomes unstable and rolls over; 
           [0044]      FIG. 12  is a diagrammatic rear elevational view of a vehicle having a second embodiment of the deployable running board depicted in the laterally extended position where the running board engages the ground; 
           [0045]      FIG. 13  is a diagrammatic rear elevational view of the vehicle depicted in  FIG. 12  but showing the maximum roll angle before the vehicle becomes unstable and rolls over; 
           [0046]      FIG. 14  is a cross-sectional view through the deployment apparatus attached to the extendable running board, the piston being depicted in the retracted position compressing the spring between the piston and the cylinder slidably housing the piston, the latching mechanism being depicted in the latched position; 
           [0047]      FIG. 15  is a cross-sectional view of the deployment apparatus similar to that of  FIG. 14  but showing the piston telescopically extended to affect a lateral movement of the attached running board, the latching mechanism being depicted in the release position; 
           [0048]      FIG. 16  is a partial cross-sectional view of the deployment apparatus depicting an elevational view of the latching mechanism in the latched position; 
           [0049]      FIG. 17  is a partial cross-sectional view of the deployment apparatus depicting an elevational view of the latching mechanism in the release position, the latch members of the telescopic piston being shown as moving toward the extended position; 
           [0050]      FIG. 18  is a cross-sectional view of a mechanical actuation mechanism associated with the deployment apparatus, the actuation mechanism being shown in a neutral position; 
           [0051]      FIG. 19  is a cross-sectional view of the actuation mechanism shown in  FIG. 16  but tilted into an activating position; 
           [0052]      FIG. 20  is an enlarged detail view of a portion of the stop mechanism carried by the activation member to prevent separation of the activation member from the base member; 
           [0053]      FIG. 21  is a cross-sectional view similar to that of  FIG. 14 , but depicting an alternative embodiment of the deployment apparatus, the piston being depicted in the retracted position compressing the spring between the piston and the cylinder slidably housing the piston, the latching mechanism being depicted in the latched position; 
           [0054]      FIG. 22  is a cross-sectional view similar to that of  FIG. 15 , but depicting the deployment apparatus shown in  FIG. 21  with the piston partially telescopically extended, the full extension of the piston being shown in phantom; 
           [0055]      FIG. 23  is a partial cross-sectional view of the deployment apparatus depicting an elevational view of the stop mechanism as oriented when the piston is in the retracted position; 
           [0056]      FIG. 24  is a partial cross-sectional view of the deployment apparatus depicting an elevational view of the stop members when the piston has been halted at an intermediate position; and 
           [0057]      FIG. 25  is a partial cross-sectional view of the deployment apparatus depicting an elevational view of the stop members when the piston is fully extended. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0058]    Referring to  FIGS. 1-7 , an automotive vehicle utilizing a laterally extendable running board apparatus incorporating the principles of the instant invention can best be seen. The vehicle  10  is depicted as a sport utility vehicle; however, one of ordinary skill in the art will readily recognize that any vehicle  10  on which a running board can be mounted can utilize the instant invention, including sport utility vehicles, pick-up trucks, vans, mini-vans, and the like. Any left and right references used within this description are used as a matter of convenience and are determined by standing at the rear of the vehicle and facing the forward direction. The principles of the instant invention are applicable to many different types or configurations of running boards, three of which are depicted in a representative manner in  FIGS. 1-7 . 
         [0059]    The running board  15  is supported from the frame  12  of the vehicle  10  and is typically positioned on both the left and right sides of the vehicle  10  to provide assistance for the ingress and egress of the passenger compartment P of the vehicle  10 . The principle of the instant invention is to cause a deployment of the running board  15  laterally outwardly relative to the vehicle  10  to change the pivot point about which the vehicle  10  turns during a rollover event. The principles of the invention are reflected in  FIGS. 8-13 . In  FIGS. 8 and 9 , the typical prior art situation is depicted in which the stable vehicle  10  in  FIG. 8  is subjected to forces that tip the vehicle  10  about the pivot point  12  defined as the engagement of the outer edge of the tire with the surface of the ground G. When a line passing vertically through the center of gravity  11  is aligned with the pivot point  12 , the vehicle  10  becomes unstable and will roll over on its side, as is depicted in  FIG. 9 . The maximum roll angle  13  is defined as the angle at which the vehicle  10  tilts relative to the normal position shown in  FIG. 8 . In the typical prior art situation, this maximum roll angle is normally in the range of 45-52 degrees, depending on the height and configuration of the vehicle  10 . 
         [0060]    In  FIGS. 10 and 11 , the running board  15  is extended laterally to change the position of the pivot point  14  laterally outwardly to be located where the extended running board  15  engages the surface of the ground G. As reflected in  FIG. 11 , the maximum roll angle  13  increases to approximately 70 degrees. Depending on the size and configuration of the vehicle  10 , the running board  15  would engage the surface of the ground G to establish the pivot point  14  when the vehicle  10  tilts to an angle of about 30 degrees. Accordingly, the extended running board  15  increases the resistance of the vehicle  10  to a rollover event by increasing the maximum roll angle  13  at which the vehicle  10  loses stability. 
         [0061]    A slightly different embodiment of the deployable running board  15  is reflected in  FIGS. 12 and 13 . In this embodiment, the running board is deployed outwardly and downwardly so that the extended running board  15  engages the ground G sooner than in the embodiment depicted in  FIGS. 10 and 11  to establish the pivot point  14 . As depicted in  FIG. 12 , the vehicle  10 , depending on size and configuration, would engage the running board  15  into the ground G when the vehicle  10  has tilted approximately 17 degrees, as compared to approximately 30 degrees for the embodiment depicted in  FIG. 10 . Since the engagement of the running board  15  with the ground G also establishes a resistance to continued motion of the vehicle  10 , i.e. the engaged running board  15  would tend to reduce the vehicle&#39;s velocity, yawing and sliding movement, the earlier engagement of the downwardly angled, extended running board  15  can help stabilize the vehicle  10  before reaching the maximum roll angle. With the pivot point  14  being slightly closer to the vehicle  10 , given the same amount of movement of the running board  15 , the maximum roll angle  13  is reduced to approximately 65 degrees; however, this maximum roll angle is still greater than is found in the typical prior art situation depicted in  FIGS. 8 and 9 . 
         [0062]    The static stability factor (SSF) of a vehicle is computed by the dividing half of the vehicle&#39;s transverse width by the height of the center of gravity above the surface of the ground. Thus, SSF=T/2 H. By extending the position of the pivot point  14  for the vehicle outboard of the tire, the effective transverse width of the vehicle is increased by the distance from the pivot point  12  at the outer edge of the tire to the pivot point  14  at the point of contact of the extended running board  15  with the ground G. Since the value of T is increased in the above formula, the value of the effective SSF is similarly increased. 
         [0063]    Referring now to  FIGS. 1-7 , the deployable running board  15  can best be seen. The running board  15  is supported from the frame of the vehicle  10  in a manner to allow the outward movement thereof The running board  15  can have a fixed base member  16  and a movable member  18  mounted on the fixed base member and its support brackets, but movable relative thereto. The support of the movable member  18  on the fixed base member  16  allows the running board  15  to support a person getting in or out of the passenger compartment of the vehicle  10 . The outer beam of the movable member  18  can be comprised of a sled runner type beam or individual pads attached to the outer end,  14  of the telescopic members  20 . One skilled in the art will readily recognize that other support configurations for the running board  15  are possible to allow the function of support for ingress and egress for the vehicle, while allowing the running board  15  to be deployed laterally outwardly in the event of a rollover. A deployment apparatus  20  is attached to the movable member  18  of the running board  15  to affect the laterally outward movement thereof when a rollover event is sensed. An actuation mechanism  40  is operatively associated with the deployment apparatus  30  to cause the deployment of the movable member  16 . 
         [0064]    Different representative configurations of the running board  15  are shown in  FIGS. 3-7 . In  FIGS. 3 and 4 , a full sled type of running board  15  is shown in which the entire running board  15  is mounted on the deployment apparatus  20  and is extended outwardly thereby. A central support  19  may be required provide additional support for the running board  15 . In  FIG. 5 , only the outer rail portion  18  of the running board  15  is laterally movable with respect to the inboard fixed portion  16 . In  FIGS. 6 and 7 , the running board  15  is a rail-type of running board and is move easily movable in a lateral direction. This rail-type of running board  15  is particularly adaptable for use in the alternative configuration in which the running board  15  is moved outwardly and downwardly, as will be described in greater detail below. 
         [0065]    The deployment apparatus  20  is best seen in  FIGS. 14-17 . Preferably, the deployment apparatus  20  is formed of a telescopic assembly that includes a base member  21  and an extendable activation member  22 . Preferably, a spring  25  is compressed between the activation member  22  and the base member  21  to spring-load the activation member  22  for deployment. The shape of the deployment apparatus  20  can be cylindrical, rectangular, or any other shape conducive to telescopic movement. Anti-friction members  24 , such as Teflon or polymer spacers, are optionally used between the base member  21  and the activation member  22  to facilitate the rapid telescopic extension of the activation member  22 . A latching mechanism  30  is mounted at the end of the base member  21  to cause a release of the activation member  22  when a rollover event is sensed. The running board  15 , or the extendable portion  18  thereof, is connected to the activation member  22  so as to be extendable therewith. 
         [0066]    The latching mechanism  30  is mounted on the end of the base member  21  by axially extending mounts  26 . The activation member  22  includes a pair of axially extending arms  23  that project through openings in the end plate  29  of the base member  21  to extend along the mounts  26  for engagement by the latching mechanism  30  through an opening  23   a . The latching mechanism  30  is formed of a latch member  31  pivotally supported in each respective mount  26  and including a keeper member  32  positionable within the opening  23   a . The keeper member  32  is formed with a cam surface  33  directed inwardly toward the center of the end plate  29  so that the force exerted by the spring  25  is operable to move the keeper member  32  out of the opening  23   a  when released. The distal end of the keeper member  32  is formed with a curved pocket  34  to receive the locking end  36  of the trip member  35 . 
         [0067]    A trip member  35  is also pivotally supported in each respective mount  26  and is formed with a locking end  36  and a trip end  37  on opposing sides of the pivotal mount, with the trip end  37  being inboard of the locking end  36 . The locking end  36  fits into the pocket  34  of the corresponding latch member  31 . Since the spring force exerted on the keeper member  32  urges the latch member  31  outwardly out of the opening  23   a  in the arm  23 , the pocket  34  is urged into engagement with the locking end  36  of the trip member  35  to freeze both the latch member  31  and the trip member  35  into a secured position, as is depicted in  FIG. 16 , with the trip ends  37  of the respective trip members  35  being oriented in general transverse alignment and in close proximity to one another. The spring force on the latch member  31  fixes the locking end  36  within the pocket  34  which prevents the latch member  31  from moving out of the opening  23   a . With the keeper member  32  in interference with the arm  23 , the activation member  22  is restrained in the retracted position, as depicted in  FIG. 14 . 
         [0068]    The latching mechanism  30  is actuated by an apparatus, such as a solenoid  39  connected to an electronic roll sensor  38 , or other mechanical device  40 , which will be described in greater detail below, to force a movement of the trip ends  37  of the trip members  35 , as is depicted in  FIGS. 15 and 17 . The forced movement of the trip ends  37  results in a pivotal movement of the trip members  35  to move the locking ends  36  out of engagement with the corresponding pockets  34 . Without the trip members  35  preventing the latch members  31  from pivotally moving, the force exerted on the keeper members  32  by the spring  25  on the cam surfaces  33  pops the keeper members  32  out of the openings  23   a  and frees the activation member  22  to extend outwardly from the base member  21 . Because of the strength of the spring  25 , the telescopic projection of the activation member  22  is fairly rapid. With the running board  15  connected to the activation members  22 , the extension of the activation members  22  results in a lateral movement of the running board  15  connected thereto, as is depicted in  FIGS. 1 and 2  in phantom. 
         [0069]    One skilled in the art will recognize that the latching mechanism  30  can also be formed with a single latch member (not shown) on each respective mount  26  without a separate trip arm. In such a configuration, the latch members could be restrained in the locking position by a solenoid, or other device that can be energized by a sensor to cause the latch members (not shown) to pivot outwardly to affect release of the activation member  22 . 
         [0070]    To prevent the activation member  22  from completely separating from the base member  21 , the deployment apparatus  20  also incorporates a stop mechanism  45 , best seen in  FIGS. 14 ,  15  and  20 , that prevents the separation of the activation member  22 . Preferably, the stop member  45  is a spring-loaded pin  46  retained within a housing  47  capturing a spring  48  to extend the pin  46  through a hole  49  in the base member  21  when the pin  46  becomes aligned therewith upon extension of the activation member  22  from the base member  21 . The housing  47  could be carried by the base member  21  on the outside surface thereof so that the spring-loaded pin  46  extends through an opening (not shown) formed in the activation member  22 . However, because of the desire to provide a deployment apparatus  20  that can be reset, as is described in greater detail below, the housing is better positioned internally of the activation member  22 . 
         [0071]    An alternative embodiment of the stop mechanism  45  is shown in  FIGS. 21-25 . Instead of the spring-loaded pin  46  having a detent ball that projects through holes  49  in the base member  21 , the pin  46  is formed with a cam surface  45   a  that causes the pin  46  to retract into the activation member  22  when the activation member  22  is moving outwardly. The base member  21  is formed with at least one pair of intermediate openings  49   a  between the respective ends of the base member  21 , and preferably two pairs of intermediate openings  49   a . If the spring-loaded pins  46  pop into the intermediate opening  49   a  while the activation member  22  is being deployed outwardly from the base member  21 , the engagement between the cam surface  45   a  and the perimeter of the intermediate opening  49   a  causes the pin  46  to retract into the base member  21  so as to not be restrictive to the deployment of the activation member  22 . At the end of the base member  21 , a stop block  28  is attached to the interior of the base member  21  to be engagable with a corresponding retainer block  27  affixed to the exterior side of the activation member  22  and positioned to interfere with the stop block  28 . Thus, when the activation member  22  is fully deployed, the interference between the retainer member  27  and the stop block  28  prevents the activation member  22  from becoming disengaged from the base member  21 . 
         [0072]    The pins  46 , however, are operable to prevent the activation member  22  from being retracted back into the base member  21 . Since the cam surface  45   a  is only located on one side of the pin  46 , the exertion of a force on the activation member  22  to urge the activation member  22  back into the base member  21  is countered by the extension of the pin  46  into the hole  49 ,  49   a  with which the pin  46  is engaged. Thus, if the running board  15  encounters an object, such as a curb, that prevents the full deployment of the attached activation member  22  from the base member  21 , the pins  46  will not have reached the end openings  49  to lock the activation member  22  in place on the base member  21 . Accordingly, the activation member  22  can slide inwardly relative to the base member  21  until the pins  46  align with an intermediate opening  49   a , at which time the pins  46  will extend through the intermediate opening  49   a  and prevent any further retraction of the activation member  22  into the base member  21 . Then, if the obstacle becomes non-interfering, the activation member  22  is free to fully extend to the end of the base member  21  where the pins  46  will extend through the openings  49  and lock the activation membe into place. Retraction of the pins  46  would be accomplished substantially the same as is described above with the first embodiment described above. 
         [0073]    An alternative orientation of the deployment apparatus  20  is depicted best in  FIG. 2  and represented in  FIGS. 12 and 13 . Instead of mounting the deployment apparatus  20  in a horizontal orientation, as is depicted in  FIG. 1 , for example, the deployment apparatus  20  is positioned at an angle to horizontal so that the extension of the activation member  22  will be outwardly and downwardly toward the ground. As is noted above with respect to  FIGS. 12 and 13 , this angular orientation of the deployment apparatus  20  places the pivot point  14  a little closer to the vehicle  10  than the horizontal orientation would create, but still increases the effective transverse width of the vehicle  10  and the corresponding SSF value. The benefit of the angular acceleration is that the tipping points  14  will touch the ground earlier than a horizontally placed equal length deployment apparatus. This will result in acting an early counter balancing force to prevent complete rollover. One skilled in the art will recognize that the sloped or angular orientation of the deployment apparatus  20  can reduce the length of the deployment apparatus  20  as the amount of movement toward the ground G would preferably be less than needed for a horizontal extension of the running board  15 . 
         [0074]    Preferably, each running board  15  would be attached to a pair of deployment apparatus  20  spaced fore-and-aft on the running board  15 . Extension of the running board  15  would require activation of both deployment apparatuses  20 . The running board  15  on both sides of the vehicle  10  would be similarly equipped. While the sensor  38  can be operable to activate only the running board on the low side of the vehicle, sometimes the vehicle will bounce back to roll over the other side, which could happen during certain maneuvers, whereupon the sensor  38  will then activate the deployment apparatus  20  on the opposite side of the vehicle  10  to extend that running board  15  as well. 
         [0075]    Once activated, the mechanically operable deployment apparatus  20  can be reset, provided that the components thereof have not been damaged in a manner that would prevent the resetting and subsequent operation of the deployment apparatus  20  in a proper manner. To reset the deployment apparatus, the pin  46  is pushed back into the housing  47  while the activation member  22  is slightly retracted into the base member  21  against the spring  25  so that the spring-loaded pin  46 , which preferably is provided with a ball at the tip thereof to facilitate movement thereof along the base member  21 , will ride on the interior surface of the base member  21  until becoming aligned with the opening  49 . The activation member  22  is then pushed completely back into the base member  21  until the arms  23  extend through the openings in the end plate  29  of the base member  21  such that the keeper members  32  are aligned with the openings  23   a . While restraining the activation member  22  against the spring  25 , the latching mechanism  30  is reset by pushing the keeper member  32  into the opening  23   a  and the trip members are re-aligned so that the locking ends  46  are positioned in the pockets  34  of the latch members  31 . The deployment apparatus is then reset for subsequent deployment as described above. 
         [0076]    Referring now to  FIGS. 1 ,  2 ,  18  and  19 , an actuation mechanism  40  is shown to provide a simple mechanical sensing and actuation operation based on inertia for use with the deployment apparatus  20 . The actuation mechanism includes a transversely extending tube  41  that extends from a contiguous location at one deployment apparatus  20  on one side of the vehicle  10  to the deployment apparatus  20  on the opposing side of the vehicle  10 . Midway between the two opposing deployment apparatuses  20 , the tube  41  is formed with a cup  42  that houses a ball  44 . The cup  42  is shaped to retain the ball  44  unless the vehicle  10  tilts to a pre-selected roll angle, as represented in  FIG. 19 , whereupon the ball is released from the cup  42  and rolls by gravity down the inclined tube  42  until the ball  44  strikes the trip ends  37  of the trip members  35  causing the trip members  35  to pivot and release the latch members  31 . The ball  44  has been found to be of sufficient size and weight to affect a pivoting of the trip members  35  when the ball is formed of steel and has a diameter of one-half inch. Accordingly, the tube  41  and the cup  42  would require a configuration to match the size and shape of the ball  44  to permit a free movement thereof. 
         [0077]    In operation, the vehicle  10  begins to incur a roll over event, tipping to one side as is represented in  FIG. 10 . Once the vehicle  10  has reached a roll angle sufficient to dislodge the ball  44  from the cup  42 , the ball  44  rolls at the speed induced by gravity to the deployment apparatus  20  on the lower side of the vehicle  10  until impacting the trip members  35 . The pivotal movement of the trip members  35  releases the latch members  31  allowing the activation member  22  to extend telescopically from the base member  21  until stopped by the spring-loaded stop members  45  interengaging the activation and base members  22 ,  21 . Once the activation members  22  are extended, the running board  15  is moved laterally outwardly by virtue of the connection thereof with the outboard ends of the activation members  22 . 
         [0078]    Once extended and engaged with the surface of the ground G, the running boards  15  serve to retard the forward velocity of the vehicle  10  and restrict any yawing and sliding movement of the vehicle  10 . Depending on the severity of the forces associated with the rollover event being incurred, the engagement of the extended running board  15  with the ground might be satisfactory to halt some rollover motion of the vehicle  10 . In the event the vehicle  10  continues to roll over, the point of engagement of the running board  15  with the ground G creates a pivot point  14  that is outboard of the tires and, thus, enables the vehicle  10  to continue through a roll angle that is greater than the maximum roll angle associated with a pivot point at the tire, before becoming unstable and rolling onto the side of the vehicle  10 . 
         [0079]    It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention.