Harvesters – Cutting – Rotating-cutting-disk type
Patent
1997-06-27
1999-07-06
Melius, Terry Lee
Harvesters
Cutting
Rotating-cutting-disk type
56295, 56DIG17, A01D 3473
Patent
active
059184507
DESCRIPTION:
BRIEF SUMMARY
FIELD OF INVENTION
This invention relates to a cutting blade (cutting geometry), having a plurality of recesses disposed along its cutting edge, which is resistant to dulling from ordinary use and that is particularly useful for replacement blades in rotary mowing equipment.
BACKGROUND OF THE INVENTION
Whether it be on replaceable blades or blades meant to be re-sharpened, e.g., a cutter bar for a sickle mower, every cutting edge has a relatively short useful life because the sharp cutting edge is worn or dulled whenever it collides with an obstacle. Eventually, the wear progresses to a point where the cutting edge no longer cuts, but rather knocks off (fractures) portions of the material the blade collides with.
Whether worn blades are to be replaced or sharpened, some dismantling and reassembly of the cutting machine is required. Those skilled in the art will appreciate how time-consuming frequent changing of the cutting blades can be.
German Patent DE-PS 221 144, describes a blade shape for replaceable blades for mowing equipment in which a number of grooves angularly disposed and lying parallel to one another are arranged on the bottom of the blade to provide a saw-like cutting edge.
As a result of wear, this blade's cutting edge becomes more saw-like with the result that sharpening is not necessary. That is to say, wear on the thin material in the area of the indentations creates a form of saw-teeth, as shown in FIG. 4 of the German Patent, which first grab the material to be cut, e.g., blades of grass, and then tear through them. Even though reference is made to a blade here, a saw is in fact what is described. The disadvantages of a saw are well-know: in the case of fresh green material, the blades are soon clogged with cutting debris, deformations can also result.
U.S. Pat. No. 3,382,654 describes a cutter bar for sickle mowers which is made of plastic. Plastic parts of lower wear-resistance are inserted in recesses on the cutting edge of this cutter bar. In contrast to the instant invention, these inserts form a continuous cutting edge when placed in their corresponding recesses and do not leave any areas of low thickness of material.
As a result of (uneven) wear on the plastic inserts having lower wear-resistance, the cutting edge creates a saw-tooth edge. As noted above, a disadvantage of saw-tooth cutting action is the accumulation of debris that blocks the cutting edge. It must also be stated that this prior art invention does not take into account the facts that the parts of low wear resistance are very quickly dulled, the final cutting is done by a sharp exposed point and that such devices are expensive to manufacture.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a cutting blade, e.g., blade sickle cutter bars, having improved wear-resistance and cutting performance, and that can be manufactured easily and inexpensively.
The present invention provides an improved cutting blade comprising a blade body including an upper surface and a cutting edge; and a plurality of recesses formed in the upper surface of the blade body so that the cutting edge is defined by a plurality thin sharp cutting regions each disposed between thick protective regions.
In the present invention, the full material (thick regions) acts as a protection for the sharp cutting edges (thin regions) therebetween. The transverse orientation of the cutting edge, i.e., not at an angle, is intended to avoid forming saw-like tips by wear. The thin cutting regions (recesses) remain sharp through the protection--left and right--of the thick (full material) regions.
It is recesses--not grooves--which present a constant thickness of material from behind, in order to form the sharp cutting regions in the best possible way across the entire width (see FIGS. 1 and 2).
The recesses are on the upper side of the blade, which also prevents grass from sliding along the cutting edge. The grass comes into contact with the upper edge of the blade and is held by the elevations, which makes the cut
REFERENCES:
patent: 3214896 (1965-11-01), Watkins et al.
patent: 5412873 (1995-05-01), Gibson
Kraemer-Maschinen U. Druckluftsysteme GmbH
Melius Terry Lee
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