Forage harvester
BACKGROUND OF THE INVENTION 
     The present invention relates generally to crop harvesting machines and more particularly to a new and improved forage harvester machine. 
     The well known agricultural practice of forage harvesting consists of cutting either green or mature crop material into discrete particles and conveying them from the field to a storage silo where they undergo an acid fermentation to give them an agreeable flavor and to prevent spoilage. This operation, which is commonly referred to as an ensilage process, converts standing crop in the field to livestock feed, commonly referred to as silage. An essential piece of farm machinery used for producing silage is the forage harvester which is adapted to gather crop material from the field, cut it into small particles and then convey the cut crop material to a temporary storage bin or wagon. Harvesters of this type are either self-propelled or pulled by a tractor. Typically, forage harvesters have a rotary cutter of a generally cylindrical configuration with knives peripherally mounted to cooperate with a fixed shear bar for cutting material as it is passed across the surface of the bar. An optical perforated recutter screen is used under some conditions to reduce the size of the cut crop even further when desirable. 
     Many forage harvesters are provided with a blower to convey the cut crop to a wagon towed behind or along side the harvester for receiving the crop. In some prior art arrangements, cut crop material is transferred to the blower from the cutterhead by intermediate conveyor means such as an auger system. Single or side-by-side augers are used at right angles or parallel to the axis of the rotary cutter. Problems have been encountered in some instances with this type of mechanism when material accumulates unevenly along the augers and causes clogging. From a design standpoint, augers provide extra moving parts that are subject to wear and thereby reduce overall reliability and serviceability characteristics of the harvester. Furthermore, use of augers increases the power requirements of the harvester especially in crop material having high moisture content. 
     To overcome problems of this nature some prior art forage harvesters have been designated with cutterhead discharging material directly to the blower without intermediate conveying means. In these direct discharge machines the blower fan rotates about an axis horizontal to the ground. The blower unit receives material fed from the cutterhead directly to the fan blades which in turn convey the cut crop material upwardly through a spout and thence to a bin or wagon. To properly accommodate direct feed type upright blowers the blower spout, the operator&#39;s platform or other important components are undesirably offset from the path of travel in prior art self-propelled harvesters. This offset has been necessitated to provide proper clearance for the spout with respect to the many other bulky components of the harvester such as the engine, an operator&#39;s platform positioned to permit proper visibility, power transmission mechanisms, a fuel tank of a sufficient size to permit long periods of field operation, etc. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is a principal object of the present invention to provide a forage harvester having its operative components uniquely arranged in a simple, efficient and economical manner. 
     A more particular object, taking into consideration the presence of propulsion mechanisms and other required operating components on a self-propelled forage harvester, is to provide an improved combination of components which cooperatively operate in a manner not heretofore known. 
     In pursuance of these and other objects, the present invention contemplates new and improved forage harvester apparatus in which the blower unit is uniquely positioned in relation to other components to improve the overall efficiency and effectiveness of the harvester while permitting various other related advantages conducive to significant advances in the practice of forage harvesting. 
     In one embodiment the forage harvester comprises a longitudinally extending mobile frame supported by at least a pair of transversely spaced wheels. A cutterhead unit is mounted on the forward portion of the frame and includes a housing having an outlet for discharging cut crop rearwardly. Disposed within the cutterhead unit is a transverse shear bar in cooperative relationship with a generally cylindrical cutterhead for cutting crop material fed by a feeder mechanism mounted on the forward portion of the frame. Mounted rearwardly of the cutterhead is a blower unit including a housing having a crop inlet in communication with the outlet in the cutterhead unit. A fan is mounted in the blower housing having two or more blades rotatable about a generally longitudinal axis for blowing crop material upwardly and away from the forage harvester machine. The present invention particularly contemplates a blower mounted with its axis inclined upwardly and forwardly whereby the fan blades have paths of rotation extending below the cylindrical cutterhead to minimize the distance between the forwardly mounted shear bar and the fan to enhance the overall performance of the forage harvester. In those instances where a recutter screen is included among the components of the forage harvester the blower position of the present invention is especially advantageous as will become apparent from the following description. 
     The foregoing and other objects, features and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, in conjunction with the accompanying sheets of drawings wherein one principal embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for illustrative purposes and are not to be construed as defining the limits of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a self-propelled forage harvester showing a machine in which the present invention is embodied. 
     FIG. 2 is a partial plan view of the forage harvester shown in FIG. 1 taken along lines 2--2 of FIG. 1. 
     FIG. 3 is a fragmentary side elevational view taken along lines 3--3 of FIG. 2. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the following description, right-hand and left-hand references are determined by facing the direction of travel of the forage harvester machine. 
     Referring to the drawings for a detailed description, a self-propelled forage harvester, generally designated by reference numeral 10, is shown in FIG. 1 to illustrate by way of example one type of equipment in which the present invention is embodied. The forage harvester 10 comprises a plurality of operative components mounted on a generally longitudinally extending frame 11 supported at its forward end by a pair of transversely spaced wheels 12 (only one shown, FIG. 1) and supported rearwardly by a pair of transversely spaced wheels 13 (only one shown, FIG. 1). 
     The frame comprises several integral members including opposing rear members 14 having forward ends terminating in a cross member 15. A pair of opposing forward members 16, 17 extend from cross member 15 with intermediate cross strut 18 and forward cross strut 20 completing the basic longitudinally extending frame. Mounted on the forward portion of the frame is a cutterhead unit 21 and just rearwardly thereof is a blower unit 22, both of which are directly below an operator control unit 23 in the form of an enclosed cab extending upwardly from a supporting platform 24. Operator control unit 23 is supported in a cantilever fashion by a pair of opposing support members 25,26 affixed to and extending upwardly and forwardly from frame cross member 15. Intermediate support members 27 are interposed between opposing forward members 16, 17 and cab support members 25,26. 
     Completely the general arrangement of typical components in forage harvesters of the self-propelled type is power unit 28 and associated fuel tank 30 (both shown in phantom) mounted within the general enclosure configuration rearwardly of the operator control unit 23. The power unit is drivingly coupled to the cutterhead unit and the blower unit and propels the harvester via means commonly known in the art including but not limited to transmission means, clutching means, drive reversing means, etc. Power and drive components are only schematically shown and are not meant to accurately depict a complete operative system. For example, a shaft 31 is simply shown as extending forwardly from power unit 28 to drive blower unit 22, whereas in practice it is common to utilize a reversing mechanism for the cutterhead and blower drives which would necessarily modify this direct connection. 
     Also shown in FIG. 1 is a rearwardly and upwardly extending spout 32 for conveying material away from the harvester, a spout support arm 33 extending from the roof of control unit 23, and cutterhead components mounted within side walls 35,36 (see FIG. 2) of a housing 34, including feeder mechanism 37, a shear bar assembly 38, a transfer chute 40 and a cutterhead 41. 
     More specifically, blower unit 22 includes a housing 42, transition 43 and spout 32. Within the housing a fan 44 is rotatably mounted for rotation about a shaft 45 which is inclined upwardly and forwardly. The inclined position of the blower unit is the very essence of this invention. Among other things, it provides improved operational relationship of the components of the harvester while enhancing the physical relationship. For example, spout 32 is disposed to clear platform 24 of the operator control unit 23 while permitting the lower end of the path of travel of the fan to extend below and forward of the rearmost portion of the path of travel of the cutterhead. This important relationship will be described in detail hereinbelow. 
     Now turning to FIGS. 2 and 3 where the components of cutterhead unit 21 are shown in detail, a cutterhead 41 of a conventional nature is depicted comprising a plurality of knives 46 mounted laterally on a series of side-by-side plate members 47. Cutterhead 41 rotates via shaft 48 journalled in side walls 35,36 of housing 34. Drive for the cutterhead is provided by a belt (not shown) in cooperative engagement with sheave 50 (FIG. 2) keyed to shaft 48. The drive for the cutterhead as mentioned above is provided by power unit 28, a detailed description of which is not essential for the purposes of the present invention. 
     The feeder mechanism 37 comprises upper feed rolls 51,52 and lower feed rolls 53,54, all of which are mounted for rotation about transverse axes in a standard manner between side wall members 35,36. Completing the cutterhead unit is shear bar assembly 38 consisting of a transverse bracket 55 (FIG. 3) affixed to forward cross strut 20. Secured to bracket 55 is a support block 56 on which is mounted shear bar 57 which is accessible through an opening in the side wall members permitting adjustment for precise positioning with respect to the cutting edges of knives 46. Adjustment of the shear bar is accomplished in a well known manner the details of which are not an essential part of this description. Attached to the shear bar assembly is a scraper member 58 mounted forward of the shear bar in cooperative relationship with the smooth surface of lower feed roll 54. Drive for the feed roll assembly is provided by input shaft 60 (FIG. 2) coupled to the power unit in a conventional manner (not shown). Motion is imparted to the feed rolls via a universal joint 61 and chain and sprocket assembly 62. 
     Mounted on frame 11 rearwardly of cutterhead 41 is blower unit 22, referred to above. Blower housing 42, secured to intermediate cross strut 18, includes a generally cylindrical chamber in which fan 44 is journalled for rotation via shaft 45. Fan blades 63 and 64, attached to fan base plate 65, are adapted to receive crop material through an access opening 66 and convey it upwardly and through transition member 43 interposed between blower housing 42 and spout 32. The lower portion of blower housing 42 is below and foward of the path of travel of the cutterhead knives 46, the outline of which is shown in FIG. 3. Drive for fan 44 is provided via shaft 31 which transmits rotational force to shaft 45 via a universal 67 (FIG. 1) coupled to a gear box 68, shown in phantom. 
     Chute 40 is provided to guide crop from the cutterhead to access opening 66 in blower housing 42. This chute, pivotally attached to brackets 70,71 via support arms 73,74 includes a transverse support rib 75, side portions 76 and a base 77 formed to guide material downwardly and rearwardly to the opening in the blower housing. Chute 40 is releasably pivotable to an access position (shown in phantom in FIG. 3) for cleaning and service purposes. In its operative position chute 40 completes the enclosure formed by the cutterhead housing and the blower housing thus controlling communication between the cutterhead and blower units. 
     In operation, harvested crop material is guided to feeder mechanism 37 via a header such as a row crop unit or a windrow pickup unit, both of which are common in the art. A unit of the row crop type is shown in phantom in FIG. 1 for exemplary purposes. Crop material guided between opposing upper and lower feed rolls 51,52 and 53,54, respectively, is fed to shear bar assembly 38. Shear bar 56 is mounted to cooperate with knives 46 on cutterhead 41 to cut crop material in small particles and propel it downwardly and rearwardly within the enclosed cutterhead unit via chute 40 and thence into access opening 66 of blower unit 22. Cut material is thereupon engaged by fan base plate 65 and blades 63,64 which in turn propel it along a generally circular path and tangentially out through transition member 43, then to spout 32 and rearwardly to a trailing wagon which is not shown. In other arrangements the spout directs material to a wagon alongside the harvester or to a bin mounted on the harvester. 
     In some conditions, a recutter screen 78 is used in a conventional manner as an integral part of cutterhead unit 21. The screen 78, shown in phantom in FIG. 3, has perforations in varying sizes, the edges of which recut crop material as it is passed through the screen from the cutterhead to the blower. The velocity of material is diminished due to the interposed recutter screen. The recutter is only used under certain conditions, such as where corn kernels require cracking, or the particle lengths of the cut crop material is critical, etc. 
     The unique apparatus and particularly the position and relationship of the blower unit in the forage harvester discussed above provides many advantages. For example, the lower limit of the path of travel of the fan blades is forward of the upper limits of the path and the lower portion of the opening is under and forward of the periphery of the cutterhead, thus enhancing the effectiveness of the blower in that cut crop material is received more directly from the shear bar unit and thereby improving overall performance without affecting efficiency. Also, the unique positional relationship of the blower opening and fan with respect to the cutterhead unit improves material flow via a recutter screen (when used) which has a natural tendency to impede material passage, i.e., material flow is assisted by gravity and the shorter path enhances average crop particle velocity. 
     Furthermore, the unique combination discussed above provides advantages in that cab placement in the center and over the cutterhead in a more rearward position improves visibility of the forage harvester operator. The blower unit is inclined from a position below operator control unit 23 to a position to the rear of the cab, whereby the spout clears the lower rear portion of platform 24 of the operator control unit via a slight cutaway portion behind the control area. This reduces the exit angle of transition member 43 with respect to the frame and thereby permits a more gradual curvature in the spout to give more efficient delivery of material than heretofore experienced. 
     A still further and important advantage of the structure of the forage harvester apparatus described above is the ability to position the cab or operator control unit over the front axle. This provides important weight distribution characteristics which are critical in the design of self-propelled farm machinery which must be designed to operate in adverse field transport conditions. Also, with respect to weight distribution characteristics of the machine described is the ability to position the blower unit directly under the cab and thus likewise dispose weight over the front axle. 
     While the preferred structure in which the principles of the present invention have been incorporated is shown and described above, it is to be understood that the invention is not to be limited to the particular details, as shown and described above, but that, in fact, widely different means may be employed in the practice of the broader aspects of the invention.