Woodworking – Special-work machine – Combined
Patent
1983-10-25
1986-02-11
Bray, W. D.
Woodworking
Special-work machine
Combined
144 2Z, 144343, A01G 2308, A01G 2300
Patent
active
045693790
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to tree harvesters.
2. Description of the Prior Art
My earlier U.S. Pat. No. 4,416,311 discloses a tree harvester which enables two trees to be delimbed simultaneously.
The harvester described in such patent incorporates a main boom on the machine; a secondary boom, supporting the grapple and shear assemblies, telescopically mounted on the main boom; and a delimbing assembly movably mounted on the main boom and operable so that as the secondary boom is extended forwardly, the delimbing head moves rearwardly along the main boom at approximately the same speed.
This harvester has proved to have considerable advantages over previously known machines (examples of which include those described in Canadian Pat. Nos. 1,046,908 and 1,051,756 of Eaton Yale Ltd; U.S. Pat. No. 3,905,407 assigned to Clark Equipment Co.; Australian Pat. No. 496860 of Eaton Yale Ltd.; and Australian Pat. Nos. 474858 and 475520 of R. L. Windsor & Son Pty. Ltd.). However, it is considered that a number of improvements can be made to that harvester.
On that harvester, the secondary boom is extended e.g. 2-4 meters, to enable a length of e.g. 4.8 meters to be delimbed in each delimbing operation. In certain applications it is considered that this forward extension places the weight of the trees too far forward of the centre of gravity of the harvester, unbalancing it.
In another area, it has been found that where the grapples are holding two trees of markedly different diameters, the smaller tree may not be on the bottom knives of the delimbed head, reducing the effectiveness of the latter.
It is also considered that the scissor-type action of the shearing head does not cut the trees as cleanly as possible, especially when docking the trees to length.
In addition, the limited movement of the shear and grapple heads relative to the machine does not enable the harvester to harvest trees which have fallen or are leaning away from the harvester.
Finally, when de-limbing the upper sections of the trees, these sections are often not strong enough to enable the trees to be fed through the shear and grapple heads to enable them to be docked to length and so one length of timber from each tree may be wasted.
SUMMARY OF THE PRESENT INVENTION
It is an object of the present invention to provide a boom assembly for tree harvesters where the secondary boom supporting the grapple assembly does not have to be extended forwardly the same distance as the delimbing assembly moves rearwardly.
It is a preferred object of the present invention to provide a grapple assembly where the grapples are so arranged that the grapples align the centres of both trees in the same plane regardless of their respective diameters, so that both trees will be supported by the base plate of the delimbing head.
In a further preferred embodiment, the shears in the shearing head are fully floating and mounted on parallelogram-type links so that they cut transversely to the axis of the shears.
In a still further preferred embodiment, the shearing and grappler assembly are mounted on a support assembly which enables the assemblies to cut trees which are lying down or inclined longitudinally or laterally relative to the machine.
In a still further preferred embodiment, the grapple assembly is operable to lift delimbed trees and deposit them on a stack.
Other preferred objects of the present invention will become apparent from the following description.
In one aspect the present invention resides in a tree harvester including:
a main boom mounted on a prime mover;
a secondary boom telescopically mounted on the main boom and supporting a grapple assembly for gripping a tree trunk and a shear assembly for severing a tree trunk;
a delimbing gantry movably mounted on the main boom;
a delimbing assembly movably mounted on the delimbing gantry;
means to extend or retract the secondary boom relative to the main boom;
means to move the delimbing gantry relative to the main boom; and
means to simultaneously move the
REFERENCES:
patent: 3833034 (1974-09-01), Menzel et al.
patent: 3892266 (1975-07-01), Puna
patent: 3896862 (1975-07-01), Windsor
patent: 3905407 (1975-09-01), Guy et al.
patent: 3915211 (1975-10-01), Barwise
patent: 4416311 (1983-11-01), Gemmell-Murdoch
Bray W. D.
Murdoch Logging Industries Pty. Ltd.
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