Abstract:
A novel rear deck service ladder and handle assembly for combine harvesters is disclosed having integral latching and height adjustment features.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to devices and methods for accessing the engine servicing platforms of combine harvesters, and it particularly relates to latches and handle assemblies for using such ladders at the rear of a combine. 
       BACKGROUND ART 
       [0002]    A variety of different ladders are presently known to provide access between the ground and the engine service platform of a combine. Folding ladders incorporating spring biased over-centering linkages to hold the ladders in stowed or closed positions without the need of a separate latching mechanism, have been known since 1978 from U.S. Pat. No. 4,131,293 by Kindle. However, typical ladders for combines remain relatively short, on the order of three to five steps, and typically the ladders simply swing or pivot from deployed position into a position for storage. Additionally, several folding step arrangements are in the prior art. Also ladders that fold into or against a vehicle body are known, and there are known embodiments utilizing tracks to align a ladder into a storage hold. 
         [0003]    However, there are certain recent model combines which have functional drawbacks inhibiting the deployment of ladders at the extreme rear end of the combine. Principally, among these drawbacks, is the difficulty of accommodating the discharge of straw and other M.O.G. (material other than grain) at the rear of the combine. That is, the ladder must be stored while also allowing ample room for the discharging straw and M.O.G. to flow freely, without being obstructed by the ladder. For purposes of homologation, the ladder, when deployed, must be long enough to extend beyond the discharge opening. Also, prior art ladders do not accommodate variations in vehicle height resulting from variation in the tire package. Furthermore, the ladders, when in the storage position at the rear, will accumulate straw and M.O.G. discharge, which subsequently spills onto the operator when he manually deploys the ladder into the service position. Also, the secondary mechanisms for positioning the access ladders in either the storage or working positions, such as push/pull cables or linkages would typically be inaccessible and unreliable at the rear of the combine. 
         [0004]    An adjustable handle and latching mechanism, for positively positioning rear ladders, that would be reliable and accessible, would provide an unexpected advancement in combine harvester design, while satisfying a longfelt need for rearwardly accessing combine harvester engine service platforms, when there is a discharge port located at the rear of the combine. 
       SUMMARY OF THE INVENTION 
       [0005]    The above-described drawbacks and others which will be apparent to those skilled in the art are overcome by a ladder assembly  40  that features a storage latch  23  whose release actuation  63  is integrated into its handle assembly  20 . A handle arm  27  of handle assembly  20 , attached to a rotatable bracket  21 , when lifted, rotates the bracket  21 , via a curved slot and stop button  53 , into contacting a latch  23  having a release lever  60  biased by a tension spring  62 , allowing adequate travel for a protrusion  63  on the bracket  21  to slowly actuate release, while maintaining secure feel for the operator when latching and unlatching the ladder during deployment from its storage position. Trim panels  50 , on the combine, protect the handle  20  for the ladder  40  deployment from varying heights, and allow modifying an individual ladder&#39;s access or grasping point  26 . 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a left side perspective of the rear access platform and ladder assembly of a combine incorporating the present invention; 
           [0007]      FIG. 2  is a perspective view of a “prior art” combine having its access ladder on the right-hand side of the combine; 
           [0008]      FIG. 3  is a perspective view of a combine showing the rear access ladder of the present invention in its stored position; 
           [0009]      FIG. 4  is a left side view of the handle assembly of the present invention in its stored position; 
           [0010]      FIG. 5  is a left side view of the handle assembly of  FIG. 4  rotated 5-15° in direction A so as to trip the release of the ladder but prior to unfolding its bottom portion; 
           [0011]      FIG. 6  shows a left side view of the positioning of the handle assembly of the present invention as it is adjusted to the desired height; 
           [0012]      FIG. 7  is a perspective close-up view of a latch mechanism for the present invention; 
           [0013]      FIG. 8  shows a left side view of the combined ladder and handle assemblies of the present invention when the ladder is in the stored position; 
           [0014]      FIG. 9  is a left side view of the combined assembly of  FIG. 8  as it is initially moved toward full deployment; 
           [0015]      FIG. 10  is a left side view of the combined assembly fully deployed but before the ladder&#39;s lower section is deployed; and 
           [0016]      FIG. 11  is a left side perspective of the combined assembly fully deployed. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    Referring generally to the accompanying drawings, the invention disclosed herein can be illustrated on an agricultural vehicle such as the combine shown generally as  10 . The combine will typically include the customary chassis or body side walls, and wheels. An operator&#39;s platform  80  for an engine service and access catwalk and guardrails is provided at the rear end of the combine. Referring to  FIG. 1 , the rear access ladder assembly  40  of the present invention is integrally stored in upright fashion on the rear access platform  80  so as to define a movable extension of the handrails. This configuration is in contrast to the prior art access ladder  400  configuration as shown in  FIG. 2  which is located on the right-hand side of the engine service platform  80 . 
         [0018]    Referring to the drawings, somewhat out-of-order,  FIGS. 8 ,  9 ,  10  and  11 , illustrate a progression from  FIG. 8 , where the rear access ladder assembly  40  of the platform  80  is fully stowed away, to  FIG. 9  where the ladder  40  is partially deployed into service, to  FIG. 10  where the ladder assembly  40  is more advanced into service, and finally  FIG. 11  where ladder assembly  40  is fully deployed and unfolded. Ladder assembly  40  comprises two hinged portions  41  and  42 . Ladder portion  41  defines a longer upper portion of ladder  40 , which portion  41  is slidingly engaged at its top end rollers  44  to move up and down along two handrails of ladder  40 . Trim panel attachment  50  attaches to the bridge plates  28  and  28 ′. 
         [0019]    Handle assembly  20  is preferably U-shaped and is illustrated in  FIGS. 4 ,  5 ,  6  and  7 . Referring now to  FIG. 4 , a storage latch mechanism  23  cooperates with the release actuation contact  63  which is integrated into pivot bracket  21 , which bracket supports handle assembly  20  that extends downward therefrom. The bracket  21  is rotatably fitted flush against bridge plate  28  and rotates about pivot point  22  via slot  51  until stop notch  53  stops said rotation. There is a similar bracket assembly  21 ′ rotatably fitted onto bridge plate  28 ′. Thus, handle  20  if rotated for about 5°-15° in accordance with directional arrow A, its protrusion  63  creates contact with latch member  23 , at latch release lever  60 , to release said latch  23  against the bias of tension spring  62  (see  FIG. 7 ), and in turn to release ladder assembly  40  from its secure storage position. The rotational movement is constrained by virtue of a curved slot  51  which guides the back end of pivot bracket  21  about stop notch  53  and against a tension spring  200 . This movement provides adequate travel so that the stop notch element  53  of bridge plate  28  which is stationary within the slot while also maintaining a firm, secure station for handle  20  when being gripped by the operator at grasp point  26 . Handle  20  features multiple height positions  20  by virtue of spring loaded pin  70  that can be moved into either of several holes  25  in pivot bracket  21  or in a sleeve  201  attached to said bracket  21  and, said height positioning of handle  20  working against the tension of spring  200 . Pivot bracket  21  rotates around its pivot point  22  by way of said pivot point  22  being a pin or the like fixed into bridge plates  28 / 28 ′ to support the handle  20  position between trim member  50  and ladder  40 . Handle assembly  20  has a vertical arms  27  and  27 ′, which arm  27  is the portion of handle assembly  20  extending up through sleeve  201  on pivot bracket  21  on the left side of the handle  20  assembly.  FIG. 7  shows jaw member  24  of latch  23  and serves as a secondary device having the primary function of positively securing and positioning ladder  40  in either the storage or working (deployed) position. A duplicate pivot plate  21 ′ is rotatably fixed on a bridge plate  28 ′ fixed opposite of bridge plate  28  connecting or bridging the ladder assembly  40  and trim  50 . 
         [0020]    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. Accordingly, the following claims are intended to protect the invention broadly as well as in the specific form shown.