Harvesters – Motorized harvester – Including driven air-blower unit
Patent
1985-10-21
1987-07-14
Johnson, Richard J.
Harvesters
Motorized harvester
Including driven air-blower unit
56255, 56 174, 56 172, A01D 3484
Patent
active
046793836
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a power operated machine which is useful for cutting grass, for example for edging an area of lawn.
BACKGROUND OF THE INVENTION
Power operated lawn edgers have been proposed heretofore, and in some instances they rely upon blades which rotate about a horizontal axis which is transverse to the direction of movement of the implement. This arrangement works particularly well but requires considerable power input, and the object of this invention is to provide a much simpler device which requires less power input, but is nevertheless effective both in the cutting of grass and the disposing of it.
One of the problems which is encountered with lawnmowers and lawn-edging machines is the tendency for impact of grass, stones, grit and the like to cause blunting of the cutter blades, and one object of this invention is to provide improvements whereby this effect is less than with some prior art machines. Another problem which is encountered is that if the blades are driven about a horizontal axis, for example, they can encounter unyielding substrates and cause considerable damage, and another object of the invention is to provide improvements whereby the likelihood of such damage is substantially reduced.
BRIEF SUMMARY OF THE INVENTION
Briefly, in this invention a lawn edger has a motor arranged with a vertical axis of rotation, a fan and cutter assembly within a hollow frame, the cutter blades being below the fan blades and extending not only radially outwardly from the axis of rotation but also axially downwardly so that they slope towards the cutting edges, and cutting is effected over a small segment of the periphery of the cutting blades, for example, by tilting the lawn edger to one side.
More specifically, the invention consists of a lawn edger comprising a hollow frame, ground engaging wheels supporting the frame, a motor carried by the frame having a rotor with a vertical axis of rotation, a fan and cutter assembly within the hollow frame, said fan and cutter assembly comprising a plurality of fan blades which extend outwardly from the axis of rotation, and a plurality of cutting blades beneath the fan blades and which extend axially downwardly and radially outwardly from the axis of rotation, and means coupling the rotor to the fan and cutter assembly for driving the latter.
Since cutting is effected over a small segment, there is a gradual lead into and out of the cutting zone by the blades as they traverse their path of travel and this does much towards limiting the damage to blades due to encountering unyielding obstructions. Furthermore, the under surfaces of the blades will abrade against the substrate with which they co-operate and this provides a "self-sharpening" action.
Notwithstanding the above however it is still possible for damage to occur and in an embodiment of the invention this damage is further reduced by having the blades sufficiently flexible and resilient that they are deflectable upwardly against the underside of respective fan blades, or hinged and springloaded downwardly. The cutter blades can for example be of spring steel strip or can be of a moulded polymeric material such as polyurethane.
Heretofore lawn edgers have usually been constructed to be supported by at least three wheels, but is is desirable with this invention that an edger can be tilted in any direction, and in one embodiment of the invention there is a ground wheel located on the axis of rotation, and a pair of half wheels on a transverse axle rearwardly thereof, the half wheels being movable together to constitute a single wheel, or being separable to constitute two transversely spaced wheels. When the half wheels are together the edger can be tilted transversely as well as in a fore and aft direction, and when they are separated the machine can be stably supported by three ground engaging surfaces.
A DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
An embodiment of the invention is described hereunder with reference to and is illustrated in the accompanying drawings in which
FIG.
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Johnson Richard J.
Sheehan Robert Douglas
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