Abstract:
A forester harvester has a house frame mounted on a base assembly and rotatable relative thereto about an axis of rotation. A boom is mounted on the house frame at a location radially offset from the axis of rotation. A cab is mounted on the house frame adjacent the boom and as forward as possible without protruding beyond the tail swing circumference of the house frame. A motor is mounted on the house frame rearward of the boom and the cab.

Description:
FIELD OF THE INVENTION 
     The present invention relates to methods and apparatus for maneuvering a vehicle through a forest and harvesting select trees within the forest. 
     BACKGROUND OF THE INVENTION 
     Recognized as a valuable resources forests are the source of constant tension between ecological concerns and ongoing needs for timber and other wood products. As a result, forest management is a serious business, and methods are practiced to conserve existing forests, improve harvesting methods, and provide for future harvesting needs. One such method involves thinning of an existing forest. The objective of thinning is to remove some trees while causing minimal damage to the surrounding environments including the underlying earth and the neighboring trees. Improvements that decrease ecological damage and/or increase production serve the interests of both the tree-hugger and the tree-cutter. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved forest harvester which is sized and configured to maneuver through a forest and harvest select trees. Additional features and/or advantages of the present invention may become more apparent from the detailed description which follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     With reference to the Figures of the Drawings wherein like numerals represent like parts and assemblies throughout the several views, 
     FIG. 1 is a top view of a forest harvester constructed according to the principles of the present invention (with some hidden lines shown); 
     FIG. 2 is a side view of the forest harvester of FIG. 1 (with some hidden lines shown); 
     FIG. 3 is a diagrammatic top view of a prior art forest harvester; 
     FIG. 4 is a diagrammatic top view of an innovative modification to the prior art forest harvester of FIG. 3; and 
     FIG. 5 is a diagrammatic top view of an innovative modification to the modified forest harvester of FIG. 4. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention involves a reorganization of tree harvester assemblies or components in order to improve visibility for an operator of the harvester Such reorganization may involve reconfiguration of one or more such assemblies or components as well. However, in order to fairly illustrate the advantages of the present invention (by means of an &#34;apples to apples&#34; comparison) the following description references assemblies and components of like size and shape on both a prior art harvester designated as 90 in FIG. 3 and a harvester constructed according to the principles of the present invention and designated as 100 in FIGS. 1-2 and 5. 
     The harvester 100 generally includes a ground engaging base 110, a house frame or upper frame 120, and a boom or harvesting arm 150. The ground engaging base 110 includes continuous or looped treads 111 and 112 which are operable to traverse a ground surface 99 in a manner known in the art. The length of the base 110, as measured parallel to the treads 111 and 112, is approximately twelve feet on the preferred embodiment. The width of the base 110, as measured perpendicular to the treads 111 and 112, is approximately eight and one-half feet on the preferred embodiment. The treads 111 and 112 constitute a relatively reliable and environmentally friendly way to traverse the floor of a forests. As compared to wheels, the treads 111 and 112 are less vulnerable on uneven ground and better distribute the weight of the harvester 100, particularly when supported on a mat of limbs and brush. 
     As shown in FIG. 2, the house frame 120 rotates about a vertical axis V relative to the ground engaging base 110, and the boom 150 pivots about a horizontal axis Z relative to the house frame 120. The horizontal axis Z is disposed rearward of the vertical axis V. The boom 150 supports a harvesting head or tool 160 which is operable to cut trees in a manner known in the art. 
     The house frame 120 extends laterally (parallel to the line W in FIG. 1) between a left side 121 and a right side 122, and longitudinally (perpendicular to the line W in FIG. 1) between a rear end 124 and a front end 126. In addition to supporting the boom 150, the house frame 120 generally includes a cab 130 and a tail portion 140. The rear end 124 of the house frame 120, which coincides with the rear end of the tail portion 140, defines a radially outermost portion of the upper frame 120 (relative to axis V). When the house frame 120 rotates relative to the base 110 about axis V, the rear end 124 defines a tail swing circumference or maximum acceptable circumference 144 at a radius of approximately five feet from the axis V. 
     The tail portion 140 includes tanks 141 and 142 for storing hydraulic fluid and fuel, respectively. The tail portion 140 is made of 2&#34; plate steel and functions as a counterweight to the boom 150 and tool 160. The rear wall of the tail portion 140 is curved to coincide with the maximum acceptable circumference 144. A motor 148 is mounted on the house frame 120, forward of the tanks 141 and 142 and rearward of the cab 130 and the boom 150. 
     The cab 130 provides an enclosure sized and configured to accommodate a person B and the controls needed to operate the apparatus 100. The front wall 136 of the cab 130 is upwardly and forwardly inclined relative to the ground surface 99. The outside edge of the front wall 136 is disposed at the maximum acceptable circumference 144 relative to the vertical axis V. A seat 139 is provided in the cab 130 and disposed forward of the horizontal axis Z. When the person B sits on the seat 139, he is intersected by a plane containing lateral line W and vertical axis V, and the center of his head occupies a position H. 
     Significant portions of the front and side walls of the cab 130 are transparent to allow the person B to see to the front and each side of the apparatus 100. The ability to see to the right side of the apparatus 100 (toward the tread 112) is one advantage of the present invention vis-a-vis the prior art and is discussed in greater detail below. 
     FIG. 3 shows what a prior art harvester 90 might look like if provided with components of similar size and shape and disposed within the same maximum acceptable circumference as the preferred embodiment 100 of the present invention. In particular, the boom 150 is centered relative to the center line C (and the treads 111 and 112), and the cab 130 is forced to occupy the position shown (with corner 133 just inside the circumference 144), and the motor 148 is forced to occupy the position shown (to the right of the boom 150). The boom 150 is shown in a configuration extending vertically upward to an intermediate pivot point, and then forward and downward to the tool 160. In FIG. 4, the line X indicates the forward edge of the vertical portion of the boom 150. From the perspective or vantage point H of a person seated in the cab 130, the lines S1 and S2 indicate the limits or boundaries of vision to the right of the tool 160 (at an elevation greater than that of the motor 148), and the lines S1 and S3 indicate the limits or boundaries of vision to the right of the tool 160 (at the elevation of the motor 148 and below). 
     FIG. 4 shows a modification to the harvester 90. In particular, the boom 150 is offset one foot to the right of the center line C (toward the right tread 112), as measured between the lines C and O. The resulting gap between the boom 150 and the cab 130 allows the latter to move to the right and forward to the position shown with reference to the preferred embodiment 100 in FIG. 5 (with the corner 133 just inside the circumference 144). The lateral offset is one foot (the same as the boom 150), and the forward movement is measured between the lines D and P, where the former indicates the location of the forward wall of the cab 130 on the prior art apparatus 90, and the latter indicates the location of the forward wall of the cab 130 on the preferred embodiment 100. The forward movement of the cab 130 allows the motor 148 to be relocated on the tail portion 140 of the frame 120 and thereby contributes to counterweight or offset the weight of the boom 150 and tool 160. 
     From the same relative vantage point H inside the cab 130, a person&#39;s range of vision to the right (at any elevation due to the relocation of the engine 148) is bounded by lines T1 and T2 (the latter generally coinciding with the boom edge X). In other words, a person seated in the preferred embodiment 100, has greater visibility and can see directly to the right side of the apparatus 100. As a result of this arrangement of components, an operator of the harvester 100 can see more of his surroundings and more capably and carefully maneuver the apparatus 100 in and about a forest. 
     The present invention has been described with reference to a preferred embodiment and a particular application. Recognizing that the foregoing description will allow those skilled in the art to recognize additional embodiments and applications, the scope of the present invention should be construed to include all such variations.