WO2002053416A2

WO2002053416A2 - Hydroformed running board

Info

Publication number: WO2002053416A2
Application number: PCT/US2002/000192
Authority: WO
Inventors: Thomas W. Longo
Original assignee: MAGNA INTERNATIONAL Inc; Magna International Inc
Current assignee: MAGNA INTERNATIONAL Inc; Magna International Inc
Priority date: 2001-01-05
Filing date: 2002-01-03
Publication date: 2002-07-11
Anticipated expiration: 2003-07-05
Also published as: AU2002235298A1; WO2002053416A3

Abstract

A running board assembly for a motor vehicle includes a tubular hydroformed U-shaped running board (10) defining a central step portion (20) and a pair of leg portions (26) extending from respective junctures (28) at opposite ends of the step portion. A mounting assembly (16) is secured to the motor vehicle and is coupled to the running board. The running board is configured to be spaced vertically downwardly from and laterally outwardly from the vehicle undercarriage such that the step portion (20) of the running board can assist a person moving through a doorway of the vehicle. The running board can be movable between an extended position and a retracted position beneath the undercarriage. Also, the running board can have accessories mounted thereto; such as, lights, electrical outlets, and mud flaps.

Description

HYDROFORMED RUNNINGBOARD

This application claims the benefit of U.S. Provisional Application Serial No. 60/259,701, filed on January 5, 2001, the entire contents of which are hereby incorporated herein by reference thereto.

Field of the Invention

The present invention generally relates to motor vehicle parts and more particularly to running boards that are attached to motor vehicles for assisting passengers entering and exiting the vehicle.

Background of the Invention

Motor vehicles such as trucks, sports utility vehicles often position the floor of the passenger compartment at a height that makes entering and exiting the vehicle difficult. Many such high ground clearance vehicles have running boards to assist persons entering and exiting a doorway of the vehicle. A running board is a support structure positioned along side a vehicle doorway that provides a foothold below the level of the vehicle floor.

Generally, running boards are stationary step or bar structures rigidly mounted to the vehicle. Stationary running boards have many disadvantages. If, for example, a stationary running board is positioned far enough below the level of the vehicle floor to assist most passengers, the stationary running board reduces the vehicle ground clearance. If, on the other hand, the stationary running board is positioned high enough to maintain the desired vehicle ground clearance, the running board is positioned too high to help passengers enter or leave the vehicle comfortably and safely. Stationary running boards also increase the vehicle width.

Additionally, running boards typically include multiple parts that are fastened together and thus the manufacturing of typical running boards is complicated.

Summary of the Invention

The present invention is directed to a running board assembly for a motor vehicle that includes a tubular hydroformed U-shaped running board having an irregularly outwardly deformed tubular metallic wall defining a central step portion and a pair of leg portions extending from respective junctures at opposite ends of the step portion. The central step portion and the pair of leg portions are integrally formed as a unitary, one-piece member. A mounting assembly is secured to the motor vehicle and is coupled to the running board. The running board is configured to be spaced vertically downwardly from and laterally outwardly from the vehicle undercarriage so that the step portion of the running board can assist a person moving through a doorway of the vehicle. The running board is constructed and arranged such that the step portion provides an upwardly facing support surface to support a foot of the person moving through the doorway and such that the pair of leg portions provide attachment for connecting the running board to the mounting assembly.

A number of features can be hydroformed into the running board during the hydro forming process. For example, the support surface of the step portion of the running board can be hydroformed to include a series of hydrofonned ribs. The tubular construction of the running board provides an interior space for mounting several accessories, including several electrically powered accessories on the running board, and the tubular construction provides a passage way to accommodate electrical wiring that is in electrical communication with the vehicle electrical system. For example, a light assembly opening may be provided at a juncture of the running board to receive a lighting assembly mounted in the opening. The wires for the lighting assembly may be disposed within a tubular interior of the running board and extend outwardly of a free end a leg portion of the running board. The running board may include an electrical outlet opening and an electrical outlet assembly may be mounted in the outlet opening to provide an electrical outlet assembly on the outside of the vehicle. The wiring for the electrical outlet assembly may be connected to the vehicle's electrical system through electrical wires passing through the tubular interior of the running board and extending outwardly of a free end a leg portion of the running board. The tubular hydroformed running board may also include mud guard openings on a leg portion for mounting a mud guard assembly. These mud guard openings may be formed by hydropiercing and may be positioned to receive the fasteners required to mount the mud guard assembly to a leg portion of the running board such that when the running board is in its retracted storage position, a mud guard assembly is positioned to block foreign matter propelled by an adjacent wheel of the moving vehicle from hitting the vehicle. The tubular hydroformed construction and location of the nmning board also provide side impact protection for the vehicle occupants.

Brief Description of the Drawings

FIG. 1 is a perspective view of a running board assembly in accordance with one embodiment of the invention mounted on a vehicle shown in fragmentary view and illustrating the running board in an extended position;

FIG. 2 is a view similar to FIG. 1 except showing the running board in a retracted position;

FIG. 3 is a perspective view of the running board illustrated in FIGS. 1 and ?•

FIG. 4 shows the running board in the retracted position and shows a vehicle frame and a vehicle tire in broken lines;

FIG. 5 is a view similar to FIG. 4 except showing the running board in an intermediate position;

FIG. 6 is a view similar to FIG. 4 except showing the running board in the extended position;

FIG. 7 is a schematic view of a hydroforming die assembly with a tubular blank therein;

FIG. 8 is a perspective view similar to FIG. 2 but illustrating a running board assembly in accordance with additional embodiments of the invention; and

FIG. 9 is a cross-sectional view of the running board taken along line 9-9 of FIG. 8.

Detailed Description of the Preferred Embodiment and Best Mode

FIG. 1 is a perspective view of a power operated running board assembly 12 mounted on a motor vehicle 14. The running board assembly 12 includes a tubular hydroformed U-shaped running board 10 constructed according to one embodiment of the present invention and a power operated mounting assembly, generally designated 16. The mounting assembly 16 is secured to the motor vehicle 14 and can be operatively connected to the running board 10 to move the running board between a retracted position as is seen in FIG. 2 and a deployed or extended position as seen in FIG. 1. This movement can be understood from FIGS. 1, 2 and 4-6. More particularly, the mounting assembly 16 is operable to move the running board 10 between (a) a retracted position (see FIG. 2, for example) in which the running board 10 is positioned under the vehicle 14 and adjacent the vehicle undercarriage 18 and (b) a deployed position (see FIG. 1, for example) in which the running board 10 is spaced vertically downwardly from and laterally outwardly from the vehicle undercarriage 18 such that a step portion 20 of the running board 10 is positioned to provide a foothold to assist a person moving through a doorway 22 of the vehicle 14.

The construction of the tubular hydroformed U-shaped running board 10 is best understood from FIG. 3. The rumiing board has a central step portion 20 and a pair of integral leg portions 26 extending from respective junctures 28 at opposite ends of the step portion 24. The step portion 24 provides an upwardly facing support surface 30 to support a foot of the person moving through the doorway and the leg portions 26 provide attachment structure for operatively connecting the mounting assembly 16 to the running board 10. Preferably a central attachment structure 32 can be rigidly secured to the step portion 24 of the running board. The attachment structure 32 is a tubular structure made of a metallic material and can be secured to the running board by welding or other appropriate method. The exemplary attachment structure 32 has a substantially oval cross section and can be formed by any appropriate method including, for example, roll forming and seam welding. The attachment structure is optional and can be used to further operatively connect the mounting assembly 16 to the running board 10.

Because many of the structural features of the running board 10 are formed during the hydroforming operation that creates the running board, a preferred method of hydroforming the running board 10 will be considered first and a detailed consideration of the structure the running board 10 will be considered thereafter. A preferred hydroforming operation for forming the hydroformed rumiing board 10 can be understood from FIG. 7. The hydroformed member 10 is formed from a tubular blank 40. The blank 40 is constructed of a suitable metallic material and has a closed transverse cross section and open tubular ends. Preferably, each blank 40 is constructed of a stainless steel.

Each blank 40 may be formed by any suitable method. For example, a continuous strip of metallic material may be shaped by roll forming and seam welding into a straight tubular configuration having a closed transverse cross section, such as a circular or oval cross section. Alternatively, a continuous length of metallic tubing may be formed by extrusion. The continuous tubular structure may then cut be to the length required to form a running board 10.

The blank 40 is preferably bent into a "U" shape prior to being placed in a hydroforming die assembly. Each leg portion 26 of the running board 10 preferably forms approximately a 90 degree angle with the central step portion 20 thereof. Because a 90 degree bend in the hydroformed member 10 is a relatively "sharp" bend (that is, a bend of greater than 30°) and requires a relatively sharp bend in the blank 40, the blank 40 can be bent according the teachings of U.S. Patent No. 5,953,945 entitled METHOD AND APPARATUS FOR WRINKLE-FREE HYDROFORMING OF ANGLED TUBULAR PARTS, hereby incorporated herein by reference in its entirety. The teachings of the '945 patent reference can be used to avoid wrinkle formation during the bending operation, particularly on the concave portion of each bend in a hydroformed part. A blank 40 may be bent in a computer numeric controlled ("CNC") bending machine prior to being placed in the die assembly or, alternatively, may be bent by stretch bending to achieve the "U" shape. The U-shaped blank 40 includes an essentially straight, longitudinally extending central portion 41 and a pair of legs 43 extending from opposite ends of the central portion 41. The juncture or "elbow" formed between the central portion 41 and each leg 43 defines a concave exterior surface portion 45 on one side thereof and a convex exterior surface portion 47 on an opposite side thereof. A suitable lubricant may be applied to the exterior of the blank 40 prior to placing it in the die assembly.

With reference again to FIG. 7, the U-shaped tubular blank 40 is then placed between the die halves 42, 44 of the die assembly 50 and the assembly is closed. The tubular blank 40 is preferably immersed in a fluid bath so that it is filled with hydroforming fluid. A hydroforming ram assembly 46, 48 is engaged with each end of the tubular blank 40 such that a ram member 52, 54 of each assembly 46, 48 seals a respective end of a tubular blank 40. The ram members 52, 54 include hydraulic intensifiers which can intensify the hydroforming fluid, thereby increasing the fluid pressure of the fluid within the blank 40 to outwardly deform tubular metallic wall, generally designated 56, of the tubular blank 40 into conformity with the die surfaces 58 of the die cavity (as disclosed in the '945 patent reference) to thereby form a hydroformed member having an exterior surface that is fixed into a predetermined regular or irregular (depending on the shape of the die cavity) configuration.

The tubular blank 40 may have, for example, an essentially circular cross section and an essentially uniform diameter prior to outward expansion during the hydroforming process. The hydroforming process may be computer controlled. The flow of the hydroforming fluid may be controlled to, in turn, control the manner in which the metallic material of the blank 40 "flows" (in a radial direction) or expands during the hydroforming process. Preferably, the expansion of the blank 40 is controlled during the hydroforming process so that the center section of the blank 40 can be expanded outwardly against the die surfaces to form the central step portion 20 of the running board 10 including a series of longitudinally extending ribs 60. It can be appreciated from FIG. 3 that the center section of the running board 10 expands only slightly (relative to the degree of expansion of the leg portions 26) during the hydroforming process. Preferably, the center portion of the blank 40 expands outwardly against the die surfaces of the die assembly and "locks" the center portion of the blank 40 to the adjacent surfaces of the die assembly before the leg portions of the blank 40 are fully expanded. The relatively larger degree of expansion of each leg portions 26 may then be achieved after the center portion of the blank 40 is locked onto the adjacent die surfaces, thus providing a larger cross section at each 90 degree bend as mentioned. The leg portions 26 can be used to mount the running board 10 to a vehicle and, as will become apparent, the enlarged interior spaces defined by the leg portions of the running board 10 may also be used to house a wide range of additional options (such as side lights, electrical outlets, electrical sensors, electrical wiring and so on) which may optionally be included in the running board 10. The relatively large cross sections of the leg portions (relative to the center portion of the running board 10) thus provide interior space and surface area for these options.

The ram members 52, 54 may push axially inwardly on opposite ends of the blank 40 to create metal flow within the blank 40 during outward expansion. The fluid pressure and the axial pressure are independently controllable. Preferably, the ends of the tubular blank 40 are pushed axially inwardly during the hydroforming operation to maintain the wall thickness of the fully formed hydroformed member 10 within a predetermined range of the wall thickness of the initial tubular blank 40. Because each juncture defines an area in which the straight tubular blank is bent at approximately ninety degrees, the exterior surface of the blank has a concave surface portion 45 and a convex surface portion 47 on generally opposite sides of the blank 40. Preferably each ram member 52, 54 applies a force to the associated end of the blank 40 so as to create longitudinal flow of metallic material within the blank 40 to maintain a wall thickness of the blank within a predetermined range and preferably the ram members apply a greater amount of force to a portion of the blank which is longitudinally aligned with the convex surface portion of the tubular blank in comparison with the amount of force applied to a portion of the blank which is longitudinally aligned with the concave surface portion of the blank so as to create a greater amount of flow of metal material toward portions of the blank 40 that are adjacent the convex surface portion in comparison with portions of the blank adjacent the concave surface portion. This inhibits wrinkle formation in portions of the blank adjacent the concave surface portion as discussed in detail in the aforesaid '945 patent reference. The ram members 52, 54 may cooperate to replenish or maintain the wall thickness of the outwardly expanding wall portions of the blank 40 so that the wall thickness of the resulting hydroformed member is within about +/- 10% of the original wall thickness of the blank 40 (i.e., to compensate for wall thinning during diametric outward expansion of the tube). The tubular blank 40 expands into conformity with the surfaces 58 defining the hydroforming die cavity so as to irregularly outwardly expand the metallic wall 56 of the blank 40 into conformity with the surfaces 40 of the die assembly 50 to provide the metallic wall 56 with a shape corresponding to the running board 10. The shape of each die cavity used to form the running board 10 thus corresponds to the shape of the rumiing board 10.

If holes are to be formed in a hydroformed running board 10, the holes may be formed while the member 10 is in the die assembly during the hydroforming operation or may be formed after the hydroformed member is removed from the die assembly along with any other required further processing of the member 10. More particularly, holes may be formed during the hydroforming process in what is known as a hydropiercing operation. A hydropiercing operation is disclosed in U.S. Patent No. 5,460,026 which is hereby incorporated by reference in its entirety into the present application. Alternatively, holes or notches of various sizes and shapes may be cut (preferably using a laser) in the running board 10 after the hydroforming operation is completed.

It can be appreciated that, as a result of the expansion of the blank 40 during the hydroforming operation, the transverse cross section of the running board 10 varies along its length so that the central portion 20 of the running board 10 may have a relatively small, somewhat rectangular cross-section and each leg portion 26 may have a relatively large, substantially circular cross-section. Preferably, the ribs 60 extend longitudinally along the length of the central step portion 20 of the running board 10, but, it is contemplated to hydro form other step surface 30 configurations such as, for example, transversely extending ribs, a grid pattern of raised rectangles, and so on. It is also contemplated to hydroform the various portions 20, 26 of the running board 10 to have other cross sectional configurations (including other sizes and shapes). It can thus be understood that altering the cross- sectional configuration of this tubular hydroformed running board 10 can be accomplished without departing from the principles of the present invention.

Forming running boards by tubular hydroforming provides manufacturers with the ability to increase running board stiffness, dimensional stability, fatigue life, and crashworthiness over nonhydroformed running boards while reducing running board mass and cost. Hydroformed running boards have a relatively high strength for many reasons, in part because of their tubular construction and in part because of a plastic deformation of the wall of the blank 40 which may occur during the hydroforming process. More particularly, the outward expansion of the tubular metallic wall of the blank 40 during hydroforming caused by the fluid pressure within the blank 40 may create a work-hardening effect which unifoπnly hardens the metallic material of the blank. Thus, hydroformed parts offer increased crashworthiness in part because of the stiffness of the metallic wall thereof due to the work hardening effect and because the tubular cross section resists deformation better than open cross section parts. Running board crashworthiness is an important issue in vehicle design and construction because the present running board 110 may be mounted on each side of a vehicle and may extend longitudinally from the front wheel well to the rear wheel well of a high ground clearance vehicle such as an SUN, for example, along the vehicle undercarriage or rocker panel. Because the running board 10 is of tubular hydroformed construction and because of its position along a respective side of the vehicle, the running board 10 offers protection to vehicle occupants in the event of a vehicle side impact. Stacked tolerances (i.e., dimensional inaccuracies of a running board 10) are also reduced by hydroforming because of the greater dimensional accuracy of each hydroformed running board (relative to nonhydroformed parts, such as stamped parts, for example).

When the running board 10 is constructed of a stainless-steel, the exterior of the running board 10 may be finished either before or after hydroforming to provide, for example, a brushed stainless steel finish or high luster stainless steel finish. The attachment structure 32 may be welded to a central portion of the step portion 20 of the running board 10 after the hydroforming operation. Preferably the attachment structure 32 is a tubular member and extends outwardly from the central portion 20 and is generally parallel to the leg portions 26 of the running board 10.

As best seen in FIG. 3, a light assembly opening 62 can be laser cut into each juncture 28 of the running board to provide an opening for an electrically powered light assembly to provide, for example, a corner end light, a side light or a rearward facing backup light on the running board 10. These lights could be visible in both the deployed and retracted positions of the hydroformed running board assembly. Preferably, a light assembly 64 (shown schematically) is installed in each opening 62 and a transparent or translucent plastic cover is disposed on the exterior of the running board 10 in covering relation to the light assembly on an outwardly facing portion of the associated juncture 28. Appropriate openings and lighting fixtures may also be provided for neon accent lighting and/or ground effect lighting.

As seen in FIG. 9, tread covers 65 can be secured over the ribs 60 to improve traction and/or the appearance of the running board 10. For example, colored accent treads (which may match the colored lighting and/or the color of the vehicle interior or exterior) may be provided on the hydroformed ribs 60 to cover and/or to enhance a hydroformed ribs effect. Colored accent treads, therefore, may be used to enhance the appearance of the vehicle and to complement the vehicle lighting as well as to increase user safety by increasing the frictional engagement between the user's foot and the running board 10. Tread covers 65 can take various forms and can be of any appropriate material, size, or shape. As an example, as illustrated in Fig. 9, the tread covers can be elastomeric to enhance traction.

The wiring (not shown) for the lighting assembly 64 (and for other applications) may extend through the tubular interior of the running board 10 and outwardly of the free end of the associated leg portion 26 of the running board. The wiring may be connected by, for example, a wiring harness to the vehicle electrical system.

An assembly opening 66 may be provided on the running board 10, preferably on an outwardly facing surface of a leg portion 26 (see FIG. 3, for example), to mount an electrical outlet assembly 67 (shown schematically) to provide, for example, 12 volt and/or 110 volt outlets (for example) on the vehicle. Electrical outlets are particularly useful when the running board 10 is mounted on a commercial vehicle, a camper, or similar vehicle. Preferably, the outlet opening 66 is covered by a weather proof cover member (not shown) that covers the electrical outlet opening and protects the electrical outlets from weather conditions when the cover member is closed. The outlet opening cover member may be spring biased into a closed, outlet-covering position and may have a peripheral rubber seal that seals the opening 66 in the closed position of the cover member.

As seen in FIG. 8, one or more mud guard assemblies and/or shields 69 may be attached to the running board 10. A mud guard 69 may be mounted to a forward leg portion of the running board in a position to block foreign matter propelled by an adjacent wheel of the moving vehicle from hitting the vehicle, particularly when the running board is in its retracted position, and/or from hitting the running board 10 itself.

An exemplary mounting assembly 16 is illustrated in FIGS. 4-6. The mounting assembly 16 includes a plurality of pairs of am s 70, 72 that are pivotally mounted between a frame 74 on the undercarriage of the vehicle 14 and the leg portions 26 and attachment structure 32 of the rumiing board 10. Only a single pair of arms 70, 72 (mounted to one leg portion 26) can be seen in FIGS. 4-6, but essentially identical pairs of arms can be mounted between the frame and the opposite leg portion of the running board and between the frame and the attachment structure 32 of the running board (see, for example, FIG. 3). The construction, mounting and operation of the pairs of arms that are not shown in FIGS. 4-6 are essentially identical to, and can be understood from, the pair of amis 70, 72 that are shown, however. A vehicle tire 73 is shown in broken lines in FIGS. 4-6.

The embodiment of the mounting assembly 16 shown and described is exemplary only and is intended to illustrate a preferred mam er in which the hydroformed running board 10 can be mounted on a representative high ground clearance motor vehicle and used to assist a passenger entering or exiting the vehicle. The particular mounting assembly 16 shown is not intended to limit the scope of the invention, however. It is contemplated to mount the running board in a fixed position on a respective side of a vehicle. It is also contemplated to movably mount the running board 10 on a high ground clearance vehicle for movement between deployed and storage positions using a wide range of mechanical, electromechanical, or hydromechanical mounting assemblies. For example, it is contemplated to mount the running board 10 to a vehicle by using any of the mounting assemblies shown and/or described in commonly assigned U.S. Patent Application Number 09/511,078, which application was filed on February 23, 2000 and is hereby incorporated by reference in its entirety into the present application.

The arm 70 can include two links that are pivotally connected to each other and to the frame 74 and leg portion 26, respectively. The arm 72 is a single link pivotally mounted between the frame 74 of the vehicle and the leg portion 26 of the running board 10. The mounting assembly 16 further includes one or more movement generating assemblies 78 mounted between the frame 74 and the running board 10. Each of the movement generating assemblies 78 can be a cylinder assembly 78 such as an air cylinder or a hydraulic cylinder. A rod 80 of the air cylinder 78 can be moved outwardly of a piston 82 of the cylinder 78 to move the running board 10 between retracted (FIG. 4) and deployed (FIG. 6) positions. Alternatively, other mechanisms for mounting and moving the running board to the vehicle 14 are contemplated. For example, an electrical motor, may be provided to move the rumiing board 10 between deployed and retracted positions. It is contemplated to provide embodiments of the running board assembly in which the running board 10 has, essentially, two functional positions, the deployed position and the retracted position. Alternatively, it is contemplated to construct and control the running board assembly so that vertical height of the deployed running board can be adjusted through an operating range of adjusted operating positions to accommodate users of different heights. It is contemplated, for example, to control the cylinder 78 to provide either two position operation of the running board (that is, deployed and retracted positions) or, alternatively, to provide "continuous" operation such that the running board can be deployed in any position within a range of operating positions between the retracted and fully deployed positions.

It can be appreciated from FIG. 6 that when the running board is deployed, the support surface 30 is positioned to assist a person moving through the associated vehicle doorway and the side lighting is positioned to be clearly visible to someone behind, in front of, or along side of the vehicle. It can be appreciated from FIG. 4, that when the running board is retracted, the lights are still clearly visible and the running board is positioned high enough so that does not interfere with or substantially reduce the vehicle's ground clearance. It can also be appreciated that the running board 10, particularly when in its retracted position, can protect the side of the vehicle and the vehicle occupants from impact in the event of a collision with the side of the vehicle. An optional stop structure 88 rigidly mounted on the frame 74 may be provided which is positioned to abut the free ends of the leg portions 26 of the retracted running board 10 to help resist lateral movement of the running board in the event of a vehicle side impact.

The running board assembly can be controlled (by, for example, an appropriately programmed computer, micro-processor, or microcontroller) to operate in many ways. For example, the running board assembly can be controlled to move the running board into its deployed position when the adjacent vehicle door is open and to move the running board into its retracted storage position when the associated door is closed. Alternatively, the running board assembly may be controlled so as to deploy the running board when the vehicle transmission is in "park" and to retracted the running board and the vehicle is in drive, reverse or neutral. Each running board 10 may be controlled independently of the others or, alternatively, all rumiing boards may be controlled simultaneously. For example, if a computer controlled control system is used to deploy the running boards in response to the opening of a door, the computer may be programmed to deploy all running boards when any door is open, or, alternatively, may be programmed to deploy only the rumiing board associated with the open door.

The vehicle operator may be provided with manually operated control devices mounted on the vehicle or on a remote control device to control movement of running boards independently or all at once. Several warning systems may be used in conjunction with the running board assemblies. For example, an audible alarm and/or a dashboard warning light may be provided to warn the driver when a running board 16 is fully or partially deployed. A sensor system with a sensor 90 may also optionally be provided in each running board assembly to warn a vehicle operator when a person is standing on a running board. This feature can be particularly valuable on vehicles in which a person standing on a running board would be out of the driver's line of site when operating the vehicle. Sensor 90 can be any type of appropriate sensor; such as photo sensors or force sensors. In an alternate embodiment (not shown), the central attachment structure 32 can be integrally hydroformed together with the U-shaped blank 40. Specifically, a cut out hole can be formed in the blank 40 and a short tubular blank portion can be welded at one end in surrounding relative to the hole. As a result, fluid pressure can be used not only to expand the leg portions and central portion of the U-shaped blank, but also can be used to simultaneously expand the short tubular portion into a desired configuration for the central attachment structure 32. h this instance, a third hydroformed rear assembly can be used to seal the free end of the short tubular blank portion that is to foi attachment structure 32.

It can be understood that the embodiment of the power operated running board assembly shown and described herein is exemplary only and not intended to limit the scope of intention. It is contemplated for example, to provide hydroformed rumiing board assemblies for mounting on a wide range of type of vehicles including sports utility vehicles, vans, trucks, and height clearance of all types.

Thus, while the invention has been disclosed and described with reference with a limited number of embodiments, it will be apparent that variations and modifications may be made thereto without departure from the spirit and scope of the invention. Therefore, the following claims are intended to cover all such modifications, variations, and equivalents thereof in accordance with the principles and advantages noted herein.

Claims

WHAT IS CLAIMED IS:

1. A running board assembly for a motor vehicle comprising: a tubular hydroformed running board having an irregularly outwardly deformed tubular metallic wall defining a central step portion and a pair of leg portions extending from respective junctures at opposite ends of said step portion, said central step portion having an upwardly facing support surface, and said central step portion and said pair of leg portions being integrally formed as a unitary, one- piece, U-shaped member; and a mounting assembly coupled to each of said pair of leg portions, said mounting assembly being configured to be secured to the motor vehicle such that said running board is positioned in order to assist a person moving through a doorway of the vehicle, said mounting assembly and said running board being constructed and arranged to permit said upwardly facing support surface of said central step portion to support a foot of the person as the person uses said rumiing board to move through the doorway of the vehicle.

2. A running board assembly as defined in claim 1, wherein said mounting assembly includes linking elements for securing to the undercarriage and operatively connected to said running board, said linking elements being operable to move said running board, including said step portion, between (a) a retracted position beneath and adjacent to the undercarriage and (b) an extended position in which said running board is spaced vertically downwardly from and laterally outwardly from both said retracted position and from the undercarriage such that said step portion of said running board extends outwardly beyond the undercarriage and is positioned to assist a person moving through a doorway of the vehicle in said extended position.

A running board assembly as defined in claim 2, wherein said linking elements are operatively connected between each of said pair of leg portions of said running board and the undercarriage and wherein said mounting assembly further includes a cylinder operatively connected between the undercarriage and said rumiing board, said cylinder being operable to move said running board between the extended and retracted positions thereof.

4. A running board assembly as defined in claim 3, wherein said cylinder is a hydraulic cylinder.

5. A running board assembly as defined in claim 1, wherein said mounting assembly includes a central attachment structure secured to said step portion of said running board and to the undercarriage.

6. A running board assembly as defined in claim 1 , wherein said running board is outwardly expanded so as to define a series of ribs on said support surface of said step portion.

7. A running board assembly as defined in claim 1 , wherein each of said pair of leg portions forms approximately a ninety degree angle with said central step portion of said rumiing board.

8. A rumiing board assembly as defined in claim 1 wherein, said running board includes a light opening and a light assembly mounted in said light opening, said light assembly including wires disposed within a tubular interior of said running board.

9. A running board assembly as defined in claim 1 wherein, said running board further includes an electrical outlet opening and an electrical outlet mounted in said outlet opening, said electrical outlet including wires disposed within a tubular interior of said running board.

10. A running board assembly as defined in claim 1 wherein, said rumiing board further includes a mud guard assembly mounted to a leg portion of the running board.

11. A running board assembly as defined in claim 11 , wherein said mounting assembly further includes a sensor and alarm system that is activated when a person stands on said running board to warn a vehicle operator that a person is standing on said running board.

12. A running board assembly as defined in claim 1, wherein a transverse, cross-sectional height of each of said pair of leg portions is larger than a transverse, cross-sectional height of said central step portion.

13. A running board assembly, comprising: a vehicle having an undercarriage and a doorway; a tubular hydroformed running board having an irregularly outwardly deformed tubular metallic wall defining a central step portion and a pair of leg portions extending from respective junctures at opposite ends of said step portion, said central step portion having an upwardly facing support surface, and said central step portion and said pair of leg portions being integrally formed as a unitary, one- piece, LT-shaped member; and a mounting assembly attached to said undercarriage and to each of said pair of leg portions to connect said running board to said undercarriage adjacent said doorway of said vehicle, said mounting assembly positioning said running board spaced vertically downwardly from and laterally outwardly from said vehicle undercarriage such that said support surface of said running board extends away from said undercarriage sufficiently to assist a person moving through a doorway of the vehicle by permitting said upwardly facing support surface of said central step portion to support a foot of the person as the person uses said running board to move through said doorway of said vehicle.

14. A running board assembly as defined in claim 13, wherein said mounting assembly includes linking elements secured to said undercarriage and operatively connected to said running board, said linking elements being operable to move said running board, including said step portion, between (a) a retracted position beneath and adjacent to said undercarriage and (b) an extended position in which said running board is spaced vertically downwardly from and laterally outwardly from both said retracted position and from said undercarriage such that said step portion of said running board extends outwardly beyond said undercarriage and is positioned to assist a person moving through said doorway of said vehicle in said extended position.

15. A running board assembly as defined in claim 14, wherein said linking elements are operatively connected between each leg portion of said running board and said undercarriage and wherein said mounting assembly further includes a cylinder operatively connected between said undercarriage and said running board, said cylinder being operable to move said running board between said extended and retracted positions.

16. A running board assembly as defined in claim 15, wherein said cylinder is a hydraulic cylinder.

17. A running board assembly as defined in claim 13, wherein said mounting assembly includes a central attachment structure secured to said step portion of said running board and to said undercarriage.

18. A iming board assembly as defined in claim 13, wherein, said running board further includes a mud guard assembly mounted to one of said pair of leg portions of said running board and positioned adjacent a tire of said vehicle.

19. A method of forming a running board assembly comprising: forming a tubular hydroformed running board by a method comprising, providing a U-shaped tubular metallic blank having a tubular metallic wall, said blank having a pair of tubular legs extending from junctures at opposite ends of a tubular central portion of the blank; placing said U-shaped tubular metallic blank into a die cavity of a die assembly, the die cavity having die surfaces, and providing a high pressure fluid into an interior of the blank to expand the metallic wall of the central portion of the blank outwardly into conformity with the surfaces of said die cavity to define a longitudinally extending central step portion of the running board and a pair of leg portions of the rumiing board; and mounting the running board below and adjacent a doorway of a vehicle such that the step portion of the rumiing board provides an upwardly facing support surface to support a foot of the person moving through the doorway.

20. A method of forming a running board assembly as defined in claim 19, wherein, mounting the running board includes mounting the rumiing board for movement between (a) a retracted position in which the running board is positioned under the vehicle and adjacent the vehicle undercarriage and (b) a deployed position in which the running board is spaced vertically downwardly from and laterally outwardly from the vehicle undercarriage such that the step portion of the rumiing board is positioned to assist in a person moving through a doorway of the vehicle.

21. A method of forming a running board assembly as defined in claim 19, wherein, the method of forming the running board further comprising, after providing the high pressure fluid, applying force to at least one end of the blank so as to create a longitudinal flow of metallic material within the blank to maintain a wall thickness of the blank within a predetermined range and so as to apply a greater amount of force to a portion of the blank that is longitudinally aligned with a convex surface portion of the blank relative to the amount of force applied to a portion of the blank that is longitudinally aligned with a concave surface portion of the blank to thereby create a greater flow of metallic material toward portions of the blank adjacent the convex surface relative to portion of the blank adjacent the concave surface portion to thereby inhibit wrinkle formation at the portions of the blank adjacent the concave surface portion.

22. A method of forming a running board assembly as defined in claim 19, wherein the method of forming the running board includes forming each leg portion of the running board in an angle of approximately 90 degrees with respect to the longitudinal extent of the step portion.

23. A method of forming a running board assembly as defined in claim 19, wherein the method of forming the running board includes forming the step portion of the running board with a plurality of longitudinally extending ribs and wherein the leg portions of the running board have larger cross sections than the step portion.

24. A method of forming a running board assembly as defined in claim 19, wherein, the method of forming the running board includes prior to mounting the running board on the vehicle, forming a light assembly opening in a juncture between one of the pair of legs of the running board and the step portion and installing a light assembly in said light assembly opening for subsequent electrical communication with the vehicle power supply.

25. A method of forming a running board assembly as defined in claim 19, wherein, the method of forming the rumiing board includes prior to mounting the running board on a vehicle, forming an electrical outlet assembly opening in a juncture between one of the pair of leg portions of the running board and the step portion and installing an electrical outlet assembly in the electrical outlet assembly opening for subsequent electrical communication with a vehicle power supply.