Abstract:
A truck ladder assembly for attachment to the underside of a truck trailer bed having a deployable ladder portion slidable from a folded storage position to an extended operational position in which the ladder portion defines a landing in spaced extended relation from the truck bed with extensible hand rails extending there from. The truck ladder is selectively secured to the underside of the trailer bed allowing for multiple repositioning and deployment of the ladder assembly.

Description:
BACKGROUND OF THE INVENTION 
   1. Technical Field 
   This device relates to truck ladders specifically ladders that are used to provide access to the truck trailer bed. Such trailer beds are located a substantial distance from the ground making access difficult without the aid of some sort of ladder. Many times truck drivers use makeshift ladders that they carry along with them that are used in all types of weather to climb up to the trailer bed. Such ladders are unstable and inherently unsafe accounting for many accidental injuries and falls. 
   2. Description of Prior Art 
   Prior art devices of this type have been developed to address the safety and ease of access issue by providing a number of portable and permanent ladder assemblies for use on truck trailers, see for example U.S. Pat. Nos. 4,139,078, 4,205,862, 5,024,292, 5,046,582, and 5,964,317. In U.S. Pat. No. 4,139,078 a ladder assembly is disclosed for use on a truck trailer having a rail and rung ladder with which is split in guide tracks up under the trailer and held by an elastic retaining strap when not in use. 
   U.S. Pat. No. 4,205,862 is directed to a truck ladder having a folding three rung portion that pivotally extends down from a support and mounting frame secured to the truck bed. 
   U.S. Pat. No. 5,024,292 illustrates a portable ladder assembly for truck trailers with mounting sleeves secured to the trailer into which telescopically extensible rail members are selectively secured, rungs extend between the rails and a ladder extension optionally extends there from. 
   U.S. Pat. No. 5,046,582 claims a portable ladder for truck cargo carrier assemblies in which multiple rung ladder portions pivotally extend from a hand rail portion which in turn is pivotally secured to the cargo opening of a truck trailer. 
   U.S. Pat. No. 5,964,317 shows a portable ladder for truck trailers having a single center rail with staggered oppositely disposed steps extending there from. A mounting bracket is selectively secured on the trailer bed surface with a central rail post secured thereto. The upper portion of the rail post that extends above the trailer surface acts as a hand rail of sorts. 
   Other prior art can be seen in Exhibit A in which a Chevron brand retractable ladder for tow trucks is shown having a pivotal adjustment ladder assembly. 
   In prior art Exhibit B a Pro Step Trucker brand ladder assembly is shown on the web page printout having a fixed open rail ladder which is hooked over the support edge of a truck trailer. A pair of ladder hand railing pivots to extend to an upstanding position. 
   SUMMARY OF THE INVENTION 
   A truck trailer ladder assembly of the invention includes an under mounted movable deployable access ladder having a support and storage position selectively secured to the underside of a trailer bed with a movable landing and folding ladder portion extending there from. The landing portion stores and supports the folded ladder and has a pair of folded full extension hand rails for safe and secure access up to and down from the truck trailer. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the ladder assembly of the invention in operable deployed position; 
       FIG. 2  is a side elevational view thereof; 
       FIG. 3  is a partial front elevational view thereof with the hand rails folded for storage sequence illustrated in broken lines; 
       FIG. 4  is a rear elevational view of the ladder assembly of the invention in open operable position; 
       FIG. 5  is a side elevational view in closed storage position on a portion of the trailer to which it is attached shown in broken lines; 
       FIG. 6  is an enlarged partial sectional view of a support bearing wheel slide assembly on lines  6 — 6  of  FIG. 1 ; 
       FIG. 7  is an enlarged partial side elevational view of the support bearing wheel slide assembly; 
       FIG. 8  is an enlarged side elevational view of the dual guide channel mounting member; 
       FIG. 9  is a side elevational view of an alternate form of the invention in which portions of the mounting assembly has been replaced with a slide pivot bracket; 
       FIG. 10  is a partial front elevational view thereof; 
       FIG. 11  is a partial perspective view of the slide bracket assembly illustrated in  FIGS. 9 and 10 ; 
       FIG. 12  is a side elevational view of an alternate form of a handrail assembly of the invention; 
       FIG. 13  is an enlarged partial end elevational view of the mounting assembly for the alternate handrails; 
       FIG. 14  is a partial side elevational view of the mounting plates for the alternate handrail assemblies; 
       FIG. 15  is a sectional view of an alternate handrail tubular member; and 
       FIG. 16  is an enlarged partial cross-sectional view of the mounting and support plate for the alternate handrail assembly. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1  of the drawings, a truck ladder assembly  10  of the invention can be seen having a fixed mounting support portion  11  and a movable ladder and storage support portion  12 . The fixed mounted support portion  11  has a pair of oppositely disposed apertured slide track members  13  and  14  interconnected to one another by a pair of upstanding cross bracket members  15  and  16  and an angle iron element  17  at one end thereof. The slide track members are of an elongated cross-sectionally T-shaped with a pair of elongated guide openings  19  and  20  in each respectively. Referring to  FIGS. 5 and 8  of the drawings, the respective guide slots  19  and  20  are vertically offset with respect to one another each with an enlarged end open portion at  19 A and  20 A respectively. The cross bracket member  16  has spaced offset opposing elongated upper lower flanges  16 A and  16 B for mounting purposes. The cross track member  15  has a pair of spaced parallel upstanding flanges  15 A and  15 B with respective right angularly extending mounting flanges  15 C and  15 D thereon. 
   Respective flanges  16 A and  15 C and  15 D provide mounting surfaces in which mounting apertures can be made to match particular configurations of the mounting environment on which they are to be attached to as will be described in greater detail hereinafter. 
   The movable ladder and storage support portion  12  has a pair of oppositely disposed frame members  21  and  22  interconnected to one another by a platform assembly  23 A. The platform assembly  23 A has a generally U-shaped inverted landing bracket  24 A secured between the frame members  21  and  22  along their respective upper edges  21 A and  22 A extending inwardly from their adjacent front perimeter edges  21 B and  22 B. 
   A pair of safety hand railing assemblies  23  and  24  are secured to and extend from oppositely disposed ends of the landing bracket  24 . Each of the hand rail assemblies  23  and  24  are pivotally secured to the landing bracket  24  by a respective mounting socket pairs  25  and  26  having tubular elements  27  extending there between from which extend a pair of spaced parallel tubular rail members  28  interconnected at their free end  29 . A second pair of tubular rail members  30  extend from a pivot sleeve  31  on the interconnected free end  29  of the hereinbefore described first rail member pair  28 . The hand rail arrangement allows for folding of the second rail members  30  down between the first rail members  28  as seen in broken lines in  FIG. 3  of the drawings. It will be seen that the mounting socket pair  26  is taller allowing the alternate folding of the first and second rail members  28  on one another in alternate fashion. Each of the frame members  21  and  22  are movably secured to the respective slide track members  13  and  14  by pairs of wheel bearing assemblies  32  as seen in  FIGS. 6 and 7  of the drawings. Each of the wheel bearing assemblies  32  have an H-shaped mounting bracket  32 A with an upper portion  32 B and lower portion  32 C. The upper portion  32 B has aligned apertures A therein with a bearing wheel  34  rotatably positioned on the axle  35  extending there through. The wheel bearing assemblies are positioned within the respective guide openings  19  and  20  as seen in  FIG. 2  of the drawings. The lower portion  32 C has multiple aligned apertures A therein for registration over the respective frame members  21  and  22  and correspondingly aligned apertures therein by multiple fasteners  33 . 
   It will be seen that the first set of wheel bearing assemblies  32  are secured to their respective frame elements  21  and  22  along their upper perimeter edges  21 A and  21 B inwardly from the respective back perimeter edges  21 C and  22 C and are aligned for engagement within respective guide slots  19  best seen in  FIG. 8  of the drawings. 
   Correspondingly, the second wheel bearing set  32  are secured to the respective frame elements  21  and  22  along their upper perimeter edges  21 A and  22 B so as to be registerable within the enlarged end opening area of the guide slots  20 . 
   A folding stair rail and rung assembly  36  extends from the ladder storage portion  12  having a pair of stair segments  37  and  38  each with spaced parallel rail members  39 A and  39 B and  40 A and  40 B with multiple rungs  41  there between. Each of the rail member pairs  39 A and  39 B and  40 A and  40 B are pivotally interconnected at their abutting ends by respective apertured pivot blocks  42  and  43 , best seen in  FIGS. 1 and 2  of the drawings. The rails  39 A and  39 B of the upper ladder segment  37  have a pair of longitudinally spaced guide bearing assemblies  44  and  45  extending respectively there from which are registerable within respective retraction guide slots  46  and  47  in the frame elements  21  and  22  as seen in  FIGS. 1–3  of the drawings. Each of the guide slots  46  and  47  extend in longitudinally spaced relation from the respective lower perimeter edges of the frame elements  21  and  22 . 
   The guide slots  46  and  47  are bifurcated at one end defining curved upstanding portions  48  and  49  respectively. 
   In use, the bearing assemblies  44  and  45  upon deployment are positioned in the bifurcated end portions  48  and  49  of the slots  46  and  47  as seen in  FIGS. 1 ,  2  and  5  of the drawings. 
   Alternately, to collapse and store the stair rail and rung assembly  36  the lower stair section  38  is pivoted upwardly and against the upper stair section  37  as seen in broken lines in  FIG. 5  of the drawings and positioned in horizontal storage alignment at  49  with the guide bearing assemblies  44  and  45  tracking within their respective guide slots  46  and  47  sliding the collapsed stair assembly back between the respective frame elements  21  and  22  for storage, shown in broken dotted lines in  FIG. 5  of the drawings. 
   To be stored, the handrail assemblies  23  and  24  have been folded down upon one another as hereinbefore described. 
   To complete the retraction and storage of the stair assembly, the frame elements  21  and  22  are then retracted under the support portion  11  by the respective wheel bearing assemblies  32  having been retracted back within the respective guide slot pairs  19  and  20  as hereinbefore described. 
   The support portion  11  of the truck ladder assembly  10  of the invention is secured under the trailer bed  41 A shown in broken lines in  FIG. 2  of the drawings by the respective engagement flanges  15 C and  15 D and  16 A for permanent mounting. 
   Referring now to  FIGS. 9 ,  10  and  11  of the drawings, an alternate movable slide mounting bracket assembly  51  can be seen. In applications where it is desirable to be able to rapidly reposition the truck ladder of the invention along the length of the trailer. An alternate mounting bracket assemblies  50  has a pair of mounting plates  52  interconnected to one another by a tubular element  53 , best seen in  FIG. 11 . Each of the mounting plates  52  has longitudinally spaced engagement notches  54  and  55  inwardly of the respective upper perimeter edges. Each of the notches  54  and  55  have a contoured L-shaped configuration for registration onto an existing ratchet mounting rail  58  extending from the underside of the trailer as will be well understood by those skilled in the art and graphically illustrated in  FIG. 11  of the drawings. 
   The fixed mounting support portion  11  of the ladder assembly  10  has been modified at  11 ′ with the removal of the upstanding cross-support members  15  and  16  and replaced by pairs of aligned spaced apertured lugs  59  and  60  welded transversely to the respective upper surfaces of the slide track members  13  and  14  as best seen in  FIG. 11  of the drawings. 
   In use, the slide mounting bracket assembly  51  is slid onto the end of the ratchet mounting rail  58  thus movably positioning the assembly  51  on the underside of the trailer. 
   The modified mounting support portion  11 ′ is then lifted up and pivotally secured to the respective apertured plates  52  by positioning same between the respective spaced apertured lug pairs  59  and  60  and held in place by respective pivot pins  61  and  62  there through. 
   Due to the balance of the alternate mounting bracket assembly  51  wherein the effective mass of the assembly is forward of the respective pivot points when deployed the assembly will pivot upwardly engaging the underside of the trailer assembly and thus become parallel there with. 
   Retaining latches  63  are used to selectively secure the ladder assembly in position extending through apertured flanges  16 A of the cross bracket  16  as hereinbefore described. 
   It will be evident from the above description that by releasing the latches  63  and pivoting the collapsed ladder assembly on the pivot pins it can then be slid along the ratchet mounting rail  58  to any position the user wishes and then locked in place by the above referred to latch configuration at its new location. 
   Referring now to  FIGS. 12–16  of the drawings, an alternate handrail configuration  70  can be seen positioned on the truck ladder assembly  10  of the invention. The alternate handrail  70  replaces the original handrails  23  and  24  and has a pair of elongated tubular rail members  71  slidable secured to respective frame members  21  and  22 . 
   Each of the tubular rail members  71  has an elongated slot  72  within one sidewall and a longitudinally spaced and aligned retaining notch at  73  extending inwardly from a base end  74  as best seen in  FIG. 15  of the drawings. 
   Referring to  FIGS. 13 and 14  of the drawings, each of the frame members  21  and  22  has a rectangular main rail mounting plate fitting  75  secured adjacent to the respective bifurcated slot portion  48 . The rail mounting plat fittings  75  each have a stop flange  75 A extending outwardly there from for engagement with the respective tubular member  71  and will be described in greater detail hereinafter. The mounting plate fittings  75  also have a pair of vertically spaced and aligned shoulder bolts  76 A and  76 B extending there from that are registerable respectively within the slot  72  and selectively in the notch  73  upon deployment. 
   Storage retainment plate fittings  77  having an engagement bolt  77 A extending there from are secured on the respective frame members  21  and  22  and horizontally aligned and spaced relation to the respective guide slots  46  and  47 . Pairs of U-shaped guide plates  78  are positioned between their respective plate fittings  75  and  77  for guiding registration and support of the tubular rail members  71  in storage and during deployment. Referring now to  FIGS. 12 and 14  it will be seen that the multiple mounting guide and support plate fittings  75 ,  77  and  78  hold the respective tubular rail members  71  in angularly disposed relation with the frame members  21  and  22  when not in use. 
   To use and deploy the handrail configuration  70 , each of the rail members  71  are slid longitudinally forward on the shoulder bolt  76 A and within the respective guide plate  78  with the engagement of the shoulder bolt  76 A in the slot  72  as shown in broken lines in  FIG. 12  of the drawings. The respective tubular rails  71  are then pivoted upwardly on said shoulder bolts  76 A to vertical use position at  79  against the respective stop flanges  75 A and then dropped down vertically onto the lower shoulder bolts  76 B within the retaining notches  73  as previously described. In this position, the respective handrail configuration  70  perform a similar function as that of the safety handrail assemblies  23  and  24 , but avoid ancillary issues of potential use conflicts in which it has been discovered when the handrail assemblies  23  and  24  are folded flat on top of the landing bracket  24  and not deployed act as a hindrance for the user to step thereon in certain situations. 
   There are also certain situations in which the user may not wish to deploy the handrail assemblies  23  and  24  as noted because of load configurations on the trailer bed and thus the alternate handrail configuration  70  are more practical in those applications. 
   While the foregoing description is illustrated and explanative of the invention, it will be evident to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.