Patent Application
20090255758
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.
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.
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.
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.
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's access or grasping point 26.
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's platform 80 for an engine service and access catwalk and guardrails is provided at the rear end of the combine. Referring to
Referring to the drawings, somewhat out-of-order,
Handle assembly 20 is preferably U-shaped and is illustrated in
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.
