| 摘要 |
The felling head is operatively installed at the front end of a tractor vehicle, and used for debrushing a brush covered terrain. It comprises a rigid framework, from which downwardly depends a pair of flat, spaced-apart elongated skates that slidingly rest on the ground and support the framework over ground. A pair of discoid saw blades are rotatably supported by the frame, with a ground clearance of a few inches relative to the plane of the skates. The framework is hingedly attached to the tractor vehicle by of a pair of linked parallel parallelograms forced into a common pivotal displacement, each having four rigid bars hingedly attached to one another so as to form a parallelogram configuration. A pair of hydraulic cylinders act on the parallelograms and on the frame, so as to allow vertical linear movement of the frame and a distinct vertical pivotal movement thereof. Thus, when the tractor vehicle pushes the felling head over an uneven ground surface, the elongated skates will be forced under the load of the framework to flatly engage the ground surface, and concurrently the saw blades will be forced to remain parallel to the ground surface with a ground clearance. The felling head further comprises a vertical pivotal axle, to horizontally pivot the saw blades. Outwardly frontwardly divergent arms are provided to convergently bias incoming brush towards the central saw blades.
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