Cutlery – Cutting tools – Saw
Patent
1992-11-13
1994-06-14
Bray, W. Donald
Cutlery
Cutting tools
Saw
30390, 144 2Z, 144343, B27B 1700, B27B 900
Patent
active
053198565
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The object of this invention is a pruning device which allows for upright pruning of standing trees. Said pruning device comprises a shaft, one end of said shaft having a support which is articulatably joined to said shaft; a rotatable cutting blade; a cutting support device which is fixed parallel to the cutting blade for leaning the upright pruning device against a tree when cutting its branches; and a power source coupled to and rotating the cutting blade.
DESCRIPTION OF RELATED ART
The branches of trees in their growing stage are pruned off in order to obtain knotless and better raw-material from sawed timber. Conventional upright pruning of trees takes place by sawing with either a manually operated saw at the end of a shaft, or by different power equipped chain, circular or back and forth moving saws. When using a manually operated saw, problems still exist, for instance the slow working speed and the heaviness of the work, caused by the uncomfortable working position, and being accentuated by the pruning of branches located very high up. Also, when using a manual saw, the risk of branch breaking is large, which often damages the branch or tree trunk.
With the help of motor driven pruning devices, branches are more easily pruned, however poor maneuverability is still a problem, and the results of the work are inaccurate. With pruning devices of the present invention, branches can still be cut off too close to the trunk of the tree, damaging the trunk of the tree. When using conventional pruning devices, the length of the remaining stub of a branch varies considerably, depending upon the person performing the pruning operation and the prevailing pruning conditions, however no consistently even work is achieved.
An objective of the present invention is to bring forth a pruning device which eliminates some of the disadvantages of the conventional pruning devices. In particular, a purpose of the present invention is a pruning device which does not damage the trunk of a tree and the length of the stub of the branch remaining can be adjusted in advance of its cutting. Further, an aim of the present invention is to bring forward a pruning device which is uncomplicated in its structure and easy to operate.
Another object of the invention is achieved by a pruning device which is characterized by that which has been presented in the claims.
Another object of the invention is achieved by a pruning device, which has at one end of a shaft an articulated turning joint fastening a support, on which the cutting blade is fastened. A cutting support device is attached which is adjustable in the direction parallel to the axis of the cutting blade, in order to enable adjustment of the distance between the trunk of the tree and the cutting blade. When using a pruning device in accordance with the present invention, the pruning device is placed at the branch of the tree in such a way that the cutting support device is placed against the trunk of the tree, and the cutting blade of the pruning device is moved against the branch of the tree. When cutting a branch of the tree, the cutting support device is moved the cutting blade in accordance with the trunk of the tree, whereby a certain distance is maintained between the cutting blade and the tree trunk. The distance between the cutting blade and the cutting support device is adjustable, whereby the length of the remaining stub of the branch is easily predetermined. A device in accordance with the present invention is easy to operate because it is unnecessary to place the pruning device with such accuracy in relation to the branch of the tree, as must be done with conventional devices. Another advantage is in the fact that sawing performed in accordance with the present invention is performed from below upwards, whereas the branch to be cut is not torn off. Experiments have shown about a 30 percent higher speed has been achieved with pruning devices of the present inventions and the damage to the trees has been about 50 percent less compared
REFERENCES:
patent: 3373489 (1968-03-01), Giles
patent: 4006528 (1977-02-01), Katsuya
patent: 4658506 (1987-04-01), Nilsson
patent: 4726118 (1988-02-01), Mattson, et al.
patent: 4827617 (1989-05-01), Shepherd
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