Abstract:
An accessing step, mounted on a vehicle having a bumper attached to the vehicle frame, comprises a step part and a mount assembly fixedly supported on the bumper and frame, mounting the step part for swinging movement from a first operative position in which the step part extends generally horizontally to a retracted second position pivoted upwardly to lie generally vertically adjacent the bumper. The mount assembly incorporates a lock device automatically operative between the mount assembly and step part for releasably locking the step part in the second position and automatically locking up to block the step part from downwardly swinging beyond a substantially horizontal position, while permitting the step part to be swung upwardly.

Description:
This invention relates to access steps which are movable from a first operative position in which the step extends generally horizontally to a second retracted storage position. 
     BACKGROUND OF THE INVENTION 
     While many prior art constructions of this type have been patented for use on the rear bumpers of vehicles such as trucks to facilitate access to the load bed of the truck, none of the previous designs have, to my knowledge, enjoyed any substantial material commercial success in the market place. 
     One of the principal reasons for this, in my view, has been the noise generated by the step assembly when the vehicle was driven over rough roads or rough terrain, because the step assembly was not locked in its several positions. Not only did the bouncing and jouncing encountered cause annoying rattling, with many such prior art constructions, it was possible for the step to swing down from retracted position when an undue bounce or jounce moved the step assembly sufficiently to cause it to move from retracted position. Prior art constructions, to my knowledge, were also not accommodatable to the downwardly curved bumpers now used on many vehicles. 
     SUMMARY OF THE INVENTION 
     Whereas applicant has a copending application for a step designed to be used with a bumper having a substantially flat rear face, and wherein the mount device permitting pivoting of the step operates to automatically provide gravity locking of the step in both its operative and storage positions, the present invention is directed to a step of different character. The present invention provides a pivotally mounted step with lockable connector mechanism between the step and the mount for the step, which locks up in both operative and retracted positions of the step. 
     One of the many objects of the present invention is to provide a bumper step assembly suitable for bumpers having vertically downwardly curved surfaces which is readily shiftable between a lower locked position of use and a retracted storage position adjacent to the inwardly curved vertical face of the bumper. 
     Another object of the invention is to provide a pivoted bumper step which is controlled by mechanism connecting the step and mount bracket, and which automatically locks up when the step reaches horizontal position to prevent further downward pivoting of the step and provide a rigid support platform for the step. 
     A further object of the invention is to provide a step or tread which is pivotal between its use and storage positions, while being connected to its mount by mechanism which locks to prevent swinging movement of the step downwardly beyond use position and while permitting the step to be readily flipped up to its storage position. 
     Still another object of the invention is to provide a step assembly of the character described wherein the mechanism connecting the step and its mount bracket automatically locks the step in its retracted storage position when the step moves to the storage position. 
     Another object of the invention is to provide a step assembly incorporating rigidifying brace mechanism for rigidly securing the step mount assembly to the vehicle frame. 
     A further object of the invention is to design a step assembly with a step which is prevented from contacting the bumper in both its use and storage positions. 
     Still another object of the invention is to provide a step which is stable and rigid in its lowered position of use. 
     Another object of the invention is to provide a very durable step which is relatively economical to manufacture and assemble, and which can be conveniently secured to the bumper or frame of an automotive vehicle such as a truck, camper, or trailer. 
     Still another object of the invention is to provide a bumper step which is safe and reliable in use and rugged in construction. 
     Other objects and advantages of the invention will become apparent with reference to the accompanying drawings and the accompanying descriptive matter. 
    
    
     GENERAL DESCRIPTION OF THE DRAWINGS 
     The presently preferred embodiment of the invention is disclosed in the following description and in the accompanying drawings, wherein: 
     FIG. 1 is a schematic, side elevational view showing the bumper step assembly fixed to the vehicle frame and bumper and disposed in the position of use, the chain lines illustrating the movement of the bumper step to the locked folded storage position; 
     FIG. 2 is a front elevational view thereof illustrating also the lateral position of the step assembly on the end of the bumper; 
     FIG. 3 is a fragmentary end elevational view thereof; 
     FIG. 4 is an inverse plan view of the bumper step assembly only; and 
     FIG. 5 is a schematic perspective elevational view of a typical pickup truck generally illustrating the position of the tailgate, bumper, and accessing step; the tailgate being shown in the down position. 
    
    
     DETAILED DESCRIPTION 
     Referring now more particularly, first of all, to FIGS.  1 - 2  and  5  of the drawings, FIG. 5 depicts the rear end of a pickup truck PT on which the rear bumper, generally designated B, is mounted in a rearwardly protruding position on the vehicle frame, generally designated F. The bumper B extends rearwardly of and below the usual pivotal tailgate assembly TA. While considered useful with other vehicles as well, the invention is particularly concerned with providing an accessing step to be mounted on the rear bumper of full size pickup trucks having downwardly and forwardly curved lower portions. The present invention is particularly designed to be readily retrofitted to such vehicles, of which many millions have been sold over the years, and to be fitted to vehicles of this type which will be manufactured in the future. 
     The bumper B depicted includes a generally flat upper surface  10  with an upper pad  10   a  thereon, and has a rear generally vertical surface configuration, including a generally flat upper surface portion  10   b , and a lower downwardly curved portion  10   c , terminating in a forwardly extending flange surface  10   d . It is contemplated that a pair of the steps or step assemblies, generally designated S, are to be mounted on each rear bumper B, one adjacent each end of the bumper, as shown particularly in FIG.  2 . 
     Each bumper step assembly includes a mount or mount assembly, generally designated M, which includes an angular member  11  (FIG. 1) having an upper forwardly extending horizontal portion  11   a , a downwardly and rearwardly inclined portion  11   b , and a vertically extending lower flange portion  11   c . Brace bars  12  may be welded in position between the portions  11   a  and  11   c  as shown. A hex head bolt  13 , having a cylindrical shaft portion  13   a , captured in a round opening provided in the member  11  and a round opening  11   a  in bumper wall  10   d , extends through the wall portion  10   d  of the bumper and may be secured by an appropriate nut  13   b.    
     The mount M is also secured to the vehicle frame F by a brace assembly, generally designated BA, to further rigidify the mount M and provide an anti-tilt function useful, for example, when the weight of a user is not centrally applied to the step or step assembly, generally designated S. 
     The brace assembly includes a vertically extending strap  14  having an end  14   a  which may be secured by a hex head bolt or the like  15  having a cylindrical shaft portion  15   a  passing through an opening  14   b  in the portion  14   a  of the strap  14  and into the opening  15  provided in the frame member  16 . It may be fixed by a nut  17 . At its lower end  14   d , strap  14  is bolted as at  18  to an upstanding bracket  19  fixed to the portion  11   a  of the member  11  laterally centrally thereof. 
     To assure an anti-tilt, or anti-rock or twist function, a laterally extending bar  20  (FIG. 3) is provided in facial engagement with the bracket  19 , which as FIG. 3 shows, has one end engageable with the portion  11   a  of the mount as at “x”. The bolt  18 , which is anchored by a nut  18   a , passes through an opening  14   e  in the strap  14 , an opening  19   a  in the bracket  19 , and an opening  20   a  in bar  20 . At its other end, anti-twist bar  20  has a threaded socket  21  to which a threaded jam nut member  22  is fixed for reception of a threaded member or bolt  23  which is threaded in the nut  22  and can be manipulated to extend downwardly through the opening  21   a  in the socket portion  21  of bar  20  to engage the upper surface of the bumper flange portion  10   d  as shown in FIG. 3 at “y”. The brace structure described very safely and reliably fixes the step mount M in position. 
     Provided on the mount assembly M is a U-shaped pivot mount bracket, generally designated  24 , having downwardly and rearwardly extending ears or end walls  25  with pivot openings  26  therein. Pins  27 , which weld to the upper surface of the step or tread plate  28  of the step assembly S, are freely rotatable in the openings  26 . Alternatively, the pins  27  could be fixed to the ears  25  and bearings to receive them could be fixed to the tread plate  28 . 
     It will be observed that the tread plate or step portion  28  has a rearwardly and upwardly inclined terminal edge  28   a  for the purpose of deflecting the foot of a user inwardly and tending to prevent the foot from slipping off the step portion  28 . The tread plate  28  is also provided with raised tread pads  28   b  thereon in a suitable tread configuration. 
     The pivoting of step portion  28  is controlled by a connector and lock assembly, generally designated C, which extends beneath the step  28  and connects the step portion  28  to the mount assembly, generally designated M. The connector assembly C is designed to automatically lock the step portion or step  28  in the pivotally raised storage position in which it is depicted by chain lines at  28 ′ in FIG.  1 . It further is designed to lock up and furnish a fixed platform on which the tread plate  28  is supported in horizontal position, when the plate  28  is released and swung down to the use position. 
     It will be noted that the mount assembly M has a pair of rearwardly extending ears, generally designated at  11   d , with openings  11   e  for receiving pins  29  on which a pair of elongate links  30  are pivotally received. At their upper ends, the links  30  are pivotally connected to a shorter link, generally designated  31 , by a pivotal shaft  32 . At its opposite end, the link  31  is pivotally connected as at  33  to a centrally dependent post  34 , which is fixed to the step portion or tread plate  28 . Also connected between the links  30 , rearwardly of the shaft  29 , is a spanning pin  35  which cooperates with a pin  36  fixed laterally centrally to the portion  11   b  of the mount member  11 . The hook ends of a coil spring  37  are hooked in the usual manner to encircle the pins  35  and  36  and secure the coil spring  37  between them. 
     Pivotally provided on the pin member  32  is a bale-shaped handle  38 , which is useful to release the step plate  28  when it is in the raised storage position shown at  28 ′. In this position of the links  30  and  31 , designated  30 ′ and  31 ′, and shown in chain lines, the links are in over center position and accordingly lock the tread plate  28  in this storage position. The spring  37 , which is in an extended tensily stressed condition in the solid line position shown in FIG. 1, operates when the tread plate  28  is raised upwardly a predetermined distance to pull the links  30  into the over center position and, at the same time, moves the tread plate  28  the final increment into the  28 ′ position. 
     THE OPERATION 
     With the step having reached the storage position at  28 ′ in the manner explained previously, it is only necessary when it is desired to use the step, to pull on the handle  38 , shown in the  38 ′ position in FIG. 1 rearwardly to move the pivot pin  33 , shown schematically at  33 ′, rearwardly beyond the position of parallelism of links  30  and  31  to unlock the locked position of the links. The step  28  will then descend under the influence of the forces of gravity toward the position in which it is shown in solid lines in FIG.  1 . As the shorter link  31  and longer links  30  swing downwardly, the link  31  moves from the position shown at  31 ′ beyond the position of parallelism with the link  30  and swings inwardly or forwardly in generally a 180 degree arc to a position in which it locks with respect to the links  30 . The locking occurs because any further pivoting of the link  31  would need to pivot the links  30  upwardly as opposed to permitting gravity to swing them downwardly. The center line distances between the pivot points  33 ′ and  32 ′ are chosen to accomplish a lock up of the links  30  and  31  constituting the connector lock C at a point where the step tread  28  extends substantially horizontally as FIG. 1 demonstrates. 
     To restore the step or step assembly S to its storage position once again, it is merely necessary to flip the end  28   a  of the treat plate  28  upwardly to a position in which the spring  37  takes over. The upward flipping movement, which is permitted by the links  30  and  31 , can be readily accomplished with the hands or with a foot, or may result from contact with another body as, for example, if the vehicle were inadvertently backed into something with the step assembly inadvertently in the down position. 
     METHOD OF MAKING 
     The step assembly described can be relatively simply manufactured and installed. Normally, the mount assembly M described is separately manufactured and the links  30  and  31  are mounted to it with the spring  37  unattached. The length of link  31  and the links  30  are predetermined such that they will relatively lock up in the relative angular positions indicated to form a base or platform for supporting the tread plate  28 , the only connection to the plate  28  being at the downwardly projecting lug projection  34 . The length of this projection  34  is also predetermined to dispose the link  31  in the desired position with respect to pin  32 . The next step in the process is to insert the pins  27  through the openings  26  and weld or otherwise fix them to the tread plate  28 . Then the mount M can be secured to the bumper and bumper frame by positioning and tightening down the bolts  13  and  15 . The laterally outboard bolt  23 , carried by the anti-twist or tilt bar  20 , is adjusted to fit with the particular bumper B before the bolt  18  is tightened down. Finally, spring  37  can be connected. 
     It is to be understood that the embodiments described are exemplary of various forms of the invention only and that the invention is defined in the appended claims which contemplate various modifications within the spirit and scope of the invention.