Control apparatus for rotatable gearbox on crop harvester by Isabella

A gearbox receives rotational power from the drive line and transmits it to the operable components. The gearbox, mounted on the crop harvesting header in the vicinity of said longitudinal centerline forwardly of the first generally vertical pivot axis, is journaled for rotation about a second generally vertical pivot axis. A unique electrical control system effects rotational movement of the gearbox in concert with the pivotal movement of the tongue to maintain appropriate alignment between the tongue and the gearbox.

A crop harvester having a wheeled frame with a tongue pivotally connected to the frame in the vicinity of a longitudinal centerline. The tongue, rotatable about a first generally vertical pivot axis, is swingable between extreme left and right positions on opposing sides of the longitudinal centerline with its distal end adapted for connection to a prime mover. A drive line transmits rotational power from the prime mover. A crop harvesting header, suspended from the frame in a forward disposition, includes operable components for engaging and processing crop material as the harvester is pulled over a field of standing crop.

Pull type harvesting implements have been utilized for various harvesting operations for many years. These harvesting implements, supported primarily by ground engaging wheels, are made in a variety of configurations, but normally include components supported on a transverse frame to which is connected a pivotal draft member, commonly called a drawbar or draft tongue. For convenience, any draft member discussed in the following description will be referred to as a tongue.

In pull type harvesters, the tongue extends forwardly of the transverse frame for attachment to a prime mover, such as a tractor, which pulls the implement and provides operative power for various harvesting components supported by the main frame. For example, if the implement is a mower-conditioner, cutting and conditioning components mounted on the frame require operative power, which is provided mechanically or hydraulically by the tractor. Hydraulic drive systems are costly and have been fraught with operational problems, not the least of which is power limitations when large implements are involved. Thus, in light of such problems implement designers have turned to the use of a mechanical drive line between the tractor and the harvester.

This patent discloses a central gearbox mounted on the header such that the gearbox is movable relative to the implement frame. The gearbox is rotatable about a vertical axis so that the input shaft into the gearbox can generally follow the pivotal movement of the tongue, which pivots about a rearwardly located vertical axis. This eliminates the occurrence of sharp angles at the gear box under conditions where the tongue swings between its extreme angular positions.

To accomplish the coordinated movement of the rotation of the gearbox with the pivotal movement of the tongue, the '859 patent discloses a telescoping steering mechanism that interconnects the tongue and the gearbox such that the gearbox is rotated in response to swinging movement of the tongue relative to the implement frame. The telescopic action of the steering mechanism is operable to accommodate the changes in distance of the respective connecting points of the telescoping mechanism between the tongue and the gearbox, i.e., as the tongue swings from side to side, the distance changes between the different horizontally spaced pivot axes of the tongue and the gearbox. The telescopic action of the steering mechanism, along with a horizontal pivot or gimble, also allows the steering mechanism to follow the vertical movement of the header relative to the tongue without restricting movement of the header or the tongue.

This telescopic steering mechanism, as taught by the '859 patent, suffers from operational problems associated with vibration due to the loosely fitting telescopic parts and wear of the sliding parts. The implement, as can be seen in the drawings of the '859 patent, is provided with a rotatable cutting mechanism and a crop conditioning mechanism, which are typical of harvester components. The operation of harvesting components, such as these, provides a substantial amount of vibration within the implement. Since the steering mechanism is loosely constructed to permit the necessary relative pivotal movements of the header and the tongue, operational vibrations are not uncommon, leading to noise and wear in other elements and parts of the harvester. Furthermore, the looseness of the elements and the sliding action therebetween also cause substantial wear in the steering mechanism itself, resulting in increased likelihood of malfunction, or even worse, failure leading to costly downtime.

Additionally, the mechanism of the '859 patent is subject to side forces from the torque applied to the gearbox by the drive mechanism and the cutterbar forces within the crop harvesting header on which the rotatable gearbox is mounted. These external forces place a side load on the steering mechanism linkage and can result in a binding of the telescoping tubes forming the linkage, which results in a thrust load on the gearbox and the connecting apparatus, particularly when the header rises and the telescopic tubes telescope together. These telescoping tubes also present a hinge-like degree of freedom which can contribute further to vibrations in the implement.

With prior art mechanical telescoping systems, the gearbox was steered to a point on the tongue, resulting in the gearbox pivot angle always exceeding the tongue pivot angle. In the instant invention, the gearbox angle can be selected for optimum value, i.e., it can understeer, steer equally, or oversteer the tongue. Experience by applicants has demonstrated that optimum conditions are realized when the gearbox is steered equally with the tongue, resulting in equal angles in the secondary PTO with minimal gearbox rotation.

Zhongyi Hydraulic Motor Company is a professional engaged in gearbox,radial piston motor,axial piston motor,piston motor,slewing transmission,danfoss motor,hydraulic orbital motor,hydraulic steering,hydraulic steering unit,hydraulic winch. All products are strictly tested before delivery by testing bench and comprehensive testing facilities to ensure the quality.

Article Source: http://www.earticlesonline.com/Article/Control-apparatus-for-rotatable-gearbox-on-crop-harvester/860679

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