Woodworking – Process – Mechanical cutting or shaping
Patent
1988-06-10
1990-01-30
Bray, W. Donald
Woodworking
Process
Mechanical cutting or shaping
831021, 83105, 144369, B27G 1908, B26D 708, B27B 528, B27B 100
Patent
active
048967084
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method and a device for cutting or slotting rigid material, in particular wood, having a modulus of elasticity of, preferably, approximately 50,000 to 400,000, in particular 80,000 to 150,000 kg/cm.sup.2, in which a gap of finite width is cut into the material by a narrow tool comprising cutting elements, in particular a circular saw blade, at a cutting speed of over 40 m/s, and in which after passage of the cutting element a timber section is lifted off the remainder of the material and bent out of the plane of the gap.
A method of the described type has been known before from German Utility Model No. 85 34 533.4.
It is a known fact that when used for working wood or for working other materials having a similar modulus of elasticity, which can be worked with high cutting speeds, circular saw blades are subjected to high thermal stresses in the area of their teeth.
However, the suggestions made heretofore for reducing the stresses acting on the teeth of circular saw blades focussed mainly on the possible reduction of the dynamic mechanical stresses. During sawing, considerable compression stresses are encountered in the teeth due to their contact with the material to be cut during the cutting operation. Consequently, numerous proposals have been made to compensate these compression stresses by tensile stresses which can be produced by giving the circular saw blade a particular shape, in particular by providing openings in the circular saw blade. An example of such an arrangement has been described by German laid open print (Offenlegungsschrift) No. 31 31 122.
From the before-mentioned German Utility Model No. 85 34 533, a circular saw with a minimum cutting gap has been known comprising a circular saw blade designed with segmental spokes and a load cell arranged at the center of the latter, for loading the individual segments in a defined manner. In addition, the circular saw blade is slightly conical in the area inwardly of the saw teeth so that the timber section, after having passed the teeth, runs up against this conical surface, thus being slightly bent away from the plane of the gap. However, the timber section still remains within the reach of the circular saw blade, resting on the conical surface of the circular saw blade over a considerable length. In this contact area, considerable frictional forces occur between the rotating conical area of the circular saw blade and the bent-off timber section. Given the rates of feed normally used today in wood-working on the one hand and the usual diameters of circular saw blades on the other hand, the time during which the bent-off timber section remains in contact with the conical surface of the known circular saw blade may well be in the range of up to one second. However, this leads to considerable mechanical stressing of the circular saw blade and of the drive and to considerable thermal loading of the circular saw blade and the wood--both circumstances being factors which, as one knows today, should never be neglected.
Now, it is the object of the present invention to improve a method and a device of the type described above so as to reduce in particular the thermal loading of the tools used.
This object is achieved according to the invention, in a method of the type described above, by the feature of bending the timber section off in such a manner that once the timber section has left the cutting elements, it is spaced a certain distance from the circular saw blade.
In a device of the type described above, this object is achieved according to the invention by an arrangement in which a separating element is arranged on at least one broad side of the circular saw blade, the edge of the said separating element adjoining the teeth of the circular saw blade and its surface being profiled in such a manner that it gets thicker towards the axis of the circular saw blade and flatter towards the teeth, said surface extending approximately tangentially to the sides of the teeth.
The object underlying the present invention is sol
REFERENCES:
patent: 700296 (1902-05-01), Brown
patent: 866975 (1907-09-01), Staley
patent: 1644961 (1927-10-01), Sultis et al.
patent: 1764183 (1930-06-01), Rhinevault
patent: 1952136 (1934-03-01), Muller
patent: 3448780 (1969-06-01), Hervey
patent: 3583450 (1971-06-01), Gunnerman
patent: 3623520 (1971-11-01), Neild
patent: 3884422 (1975-05-01), Weichel
patent: 4210051 (1980-07-01), Fingerle et al.
Bray W. Donald
Wurster u. Dietz GmbH u. Co.
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