Land vehicles – Body elevation or tilt – Terrain slope compensation
Reexamination Certificate
1999-06-11
2001-01-16
English, Peter C. (Department: 3619)
Land vehicles
Body elevation or tilt
Terrain slope compensation
C180S041000, C144S004100, C144S034100, C414S687000
Reexamination Certificate
active
06173973
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a mechanism that connects a boom swing-house of a forestry machine to the frame of the ground engaging carriage of the machine, and more particularly to such a mechanism which is operated so as to level the swing-house in uneven or sloping terrain.
2. Discussion of the Prior Art
Forestry machines, such as feller bunchers for harvesting standing trees, are well known. In one type of feller buncher, a saw head which is used to sever the tree is mounted at the end of a boom which has its other end mounted to a turntable so as to be pivotable about a lateral axis relative to the turntable. The turntable is mounted to a turntable support so as to be pivotable about a vertical axis (when the support is vertical). A carriage which can have tracks or wheels for conveying the turntable support has a frame to which the turntable support is mounted by a leveling mechanism. The leveling mechanism is operable to vary the position and orientation of the turntable support relative to the carriage, depending upon the slope of the terrain and the orientation of the carriage on the terrain. For example, if trees are being cut on a hillside, the machine will typically be driven onto the hillside so the trees are within reach of the boom and the leveling mechanism adjusted so as to make the axis of the turntable generally vertical. The center of gravity of the swing-house assembly, which includes the boom (with cutting head attached), the engine of the machine and the operator cab, which are mounted on the turntable, should be positioned relative to the carriage so that the machine does not tip forward or backward when the tree is cut and its weight comes to rest on the butt plate of the head.
Such a mechanism may be made using linkages and hydraulic cylinders for moving the linkages as described in U.S. Pat. No. 4,679,803. In that mechanism, one set of links is provided forwardly and another set is provided rearwardly, and hydraulic cylinders connect the links both laterally and longitudinally to tilt the turntable relative to the carriage both about a lateral axis and a longitudinal axis. Other mechanisms for positioning and orienting the swing-house assembly relative to the carriage are also discussed in U.S. Pat. No. 4,679,803.
Another consideration in a forestry machine is machine height. This is important because these machines are oftentimes transported over the road. If the machine is too high in its shipping position, it will not make it under bridges or other underpasses, or may otherwise exceed the legal height limit of the road. Thus, the need for a leveling mechanism, which adds to the height of the machine, competes against providing a machine which can be transported over the road.
SUMMARY OF THE INVENTION
The invention provides a feller buncher with a leveling mechanism which can be operated over a broad angle range on both sides of a parallel position in which the turntable major axis is parallel to the carriage axis. In addition, a leveling mechanism of the invention does not sacrifice ground clearance of the carriage to provide a lower minimum height of the feller buncher.
The invention accomplishes this by providing two pivotal links for connecting the turntable support to the frame of the carriage but provides that one link is shorter than the other. Preferably, both links are connected to the carriage closer to one end than to the other, and the link closest to the one end is shorter than the other link. This arrangement permits rotating the turntable forwardly about a lateral axis relative to the carriage to a relatively high angle. In this position, since the turntable is rotatable relative to the turntable support about the turntable axis by 360°, the boom of the machine can be operated in front of the carriage, in back of the carriage, or to either side at any angular position.
When cutting or otherwise processing a tree uphill from the machine, the boom with attached feller buncher head or other implement is positioned either in front of or behind the carriage. When processing a tree downhill from the machine, in order to maintain a favorable position of the center of gravity of the machine which resists tipping of the machine downhill, the front of the machine is pointed uphill and the turntable is preferably tilted forwardly, so that its axis, which is ordinarily adjusted to be approximately vertical, is directed uphill of the carriage axis.
This construction also permits tilting the turntable support rearwardly, which serves to lower the transport height of the machine.
In another preferred aspect, a pair of hydraulic cylinders are provided for adjusting the position of the turntable support relative to the carriage. The cylinders extend between the turntable support and the frame of the carriage. The lower ends of the cylinders are pivotally connected to the frame rearward of the lower ends of both links, and the upper ends of the cylinders are laterally spaced apart on opposite sides of the center of the turntable and forwardly of the rearward link. Simultaneous and equal changes in length of the cylinders result in rotating the turntable about a lateral axis. Differential changes in length of the two cylinders result in rotating the turntable about a turntable minor axis to tilt the turntable support about a generally longitudinal axis. Thereby, the pair of hydraulic cylinders can be used to pivot the swing-house assembly forwardly and rearwardly from the parallel position and also to tilt the swing-house assembly from side to side.
Other objects and advantages of the invention will be apparent from the detailed description and drawings.
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“New FBs Madill Launches 2200s at Forest Expo” by Jim Stirling,Logging&Sawmilling Journal; Apr. 1998; pp. 89-90.
English Peter C.
Quarles & Brady LLP
Timberjack Inc.
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