Harvesters – Cutting – Hedge or plant-row trimmers
Reexamination Certificate
1999-07-09
2001-06-26
Pezzuto, Robert E. (Department: 3671)
Harvesters
Cutting
Hedge or plant-row trimmers
C056S255000, C056S503000
Reexamination Certificate
active
06250056
ABSTRACT:
This invention relates to pruning apparatus. It relates particularly but not exclusively to tractor mounted rotary blade pruning apparatus which is suitable for high speed pruning of vines, fruit trees and other vegetation.
Pruning is a necessary part of most commercial fruit and plant harvesting enterprises. Pruning at particular points in a plant's growth cycle results in optimised production of fruit or other harvestable plant matter.
There are several different ways in which pruning can be accomplished. It may be performed manually by means of shears or a slasher. This enables precise control of the regions which are to be pruned, but is very labour intensive and usually not viable for commercial activities.
There are various different types of motorised devices which are used in pruning. One type of device which can be used is a rotary saw, which consists of a disk with outwardly protruding teeth, rotating rapidly. However, rotary saws with their teeth protruding in all directions are relatively dangerous to operate, and they are not therefore the preferred choice for pruning operations. Moreover, a particular difficulty in pruning vegetation is that the vegetation tends to bend easily, and not to be brittle. Accordingly, a rotary saw or a conventional saw tends to push the material outside of the teeth, and the vegetation remains uncut unless the saw operates at particularly high speeds or there is some force applied causing the vegetation to enter the teeth of the saw.
It is possible to use a motor mower-type blade-and-disk arrangement for pruning purposes. In such an arrangement, substantially rectangular blades are moved rapidly in a circular motion by a disk, and they perform a slashing type operation on vegetation. However, the blades suffer the same problem as the teeth of a rotary saw, in that vegetation tends to bend around the sides of the path traced by the blades, rather than being cut by the blades unless it is directly forced into the path of the blades.
Another type of pruner, and perhaps the most common presently available type, consists of two blades, each of which has a number of rectangular teeth. One blade is held still, while the other blade is moved rapidly backwards and forwards in the direction of the length of the blades, so that the gaps between the rectangular teeth on the two respective blades are rapidly closed and opened in cutting actions. The relative scissor-type movement of two blades results in a much improved cutting efficiency. However, vegetation still tends to bend out of the path of the square teeth.
In an improved version of the linear motorised pruning device, the rectangular teeth are replaced with substantially triangular teeth. It has been found that this arrangement results in an improved cutting efficiency, because vegetation approaching the pruner is confronted by a point rather than the flat surface on the top of a rectangular tooth. However, there are inherent inefficiencies associated with driving a blade up and down in a piston-like manner. Maximum speed of operation is limited and various stresses are incurred through the abrupt motions. Moreover, when any of the teeth are broken, bent or otherwise damaged, it is generally necessary to replace the whole blade.
According to the present invention, there is provided a pruning machine, for pruning or trimming a row of vines or other plants, including
I. a first set of pruning apparatus including:
(a) a first mounting plate having a central axis and an outer edge;
(b) a first set of blades mounted on the first mounting plate and protruding outwardly from the outer edge;
(c) a second mounting plate having a central axis and an outer edge located close to the first mounting plate so that the respective central axes and outer edges substantially coincide; and
(d) a second set of blades mounted on the second mounting plate and protruding outwardly from the second mounting plate outer edge;
wherein in operation, the first set of blades rotates relative to the second set of blades so that scissor like cutting actions are formed between them;
and wherein the blades on the first mounting plate and/or the blades on the second mounting plate taper from a broader width at
the outer edge of the respective mounting plate to a narrower width at the point furthest from the central axis; and
II. a second set of pruning apparatus having the same features as the first set;
wherein the two sets of pruning apparatus are mounted side by side such that they form a cutting tool for cutting one side of the row of vines or other plants, the cutting tool having a length which is approximately the sum of the diameters of the first mounting plate on the first set of pruning apparatus and the second mounting plate on the second set of pruning apparatus.
The first mounting plate may be of any suitable shape and configuration. A preferred shape is a disk shape, but other shapes such as polygonal shapes, star shapes and cartwheel type shapes are also suitable. It is preferred that the first mounting plate be flat, although other shapes such as a bowl shape are also suitable.
The second mounting plate may be of any suitable shape and configuration. The preferred shapes and features are similar to those for the first mounting plate. The second mounting plate may be fixed while the first mounting plate rotates. Alternatively, the second mounting plate may rotate in a direction opposite to that in which the first mounting plate rotates. Where the second mounting plate is fixed, it may be semi-circular or some other shape which is not continuous in the full path of the rotating blades, because it is only necessary that fixed blades be provided at the locations at which cutting actually occurs.
The rotating mounting plates are preferably relatively heavy, so that they act as flywheels, applying a steady weighted force to enhance the cutting effect of the blades. This reduces the variability of load applied to the driving motor during cutting (high load when cutting thick vegetation, no load when not cutting), and results in reduced motor wear and an overall reduction in the power required of the motor. It also reduces the speed at which blades must rotate to cut vegetation effectively. As a result, suitable machines according to the present invention may be made using the standard hydraulics available on tractors, without requiring the use of an external power pack.
As a preferred feature, recesses may be provided in the first mounting plate for the attachment of blades, so that the faces of the mounting plates including the blades as presented to each other, are relatively smooth, ensuring smooth operation during rotation, and enabling the first set of blades to pass as close as possible to the second set of blades.
The blades in the first set and in the second set may be of any suitable shape and configuration. In the preferred configuration, all blades taper from a relatively broad width at the point at which the blades begin protruding outwardly from the mounting plate to a relatively narrow width or point at the part of the blade most distant from the mounting plate. In one preferred embodiment, the blades are triangular in shape, with the base of the triangle being fixed to the mounting plate and the apex of the triangle being the outer most part of the blade. In another embodiment, the blades may be of saw-tooth shape, being a triangular shape which has been distorted into a hook type or dorsal fin shape.
It is preferred although not essential that the blades on the second mounting plate be of the same shape as the blades on the first mounting plate. Nevertheless, it is possible, by way of example, for one set of blades to be substantially rectangular in shape while the other set is substantially triangular, or for one set to be substantially triangular and the other to be substantially saw-tooth in shape, or even for there to be variations in shape within a set.
It is preferred that the blades be easily removable and replaceable on the mounting plate. This has several advantages. One advantage is t
F & T Spagnolo PTY Ltd.
Kováacs Árpád F.
Oliff & Berridge PLC.
Pezzuto Robert E.
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