Cutlery – Powered planer
Reexamination Certificate
1999-10-26
2001-06-26
Watts, Douglas D (Department: 3724)
Cutlery
Powered planer
C144S230000, C144S241000
Reexamination Certificate
active
06249982
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention is based on a manual planing machine, a planer shaft, a planer knife and a spacer strip respectively.
DE-OS 91 52 65 discloses a planing machine with a cutter head or planer shaft whose elongated planer knives extend over the width of the planer shaft and can be clamped by clamping wedges which are carried by the planer shaft and are actuated by centrifugal force. The known planing machine is suitable only for clamping large-volume planer knives. The considerably smaller and thinner carbide mini reversible tips, e.g., in the standard size of 1.1 mm thickness and 5.5 mm height, cannot be clamped in any definite position in the known planing machines because they have a volume and mass roughly ten times smaller than the large-volume planer knives. The large-volume planer knife cannot be economically produced from carbide due to its large dimensions because the cost of carbide is very high, so that only high-speed steel planer knives of lesser stability and quality are considered for the known planers.
EP 01 17 991 discloses a planing machine with a planer shaft formed of profile disks, wherein a clamping wedge actuated by centrifugal force is arranged in the longitudinal groove of the planer shaft. This planer shaft is also not suitable for receiving mini reversible tips, but only for conventional high-power high-speed steel knives with an approximate thickness of 3 mm and a height of 11.5 mm. These would also be just as uneconomical as carbide knives in terms of construction.
Patent FR 2 477 460 discloses a clamping device at a planer shaft for large-volume rusticating planer knives with a corrugated cutter which, alternatively, can also receive dual-cutting straight mini reversible tips. For this purpose, a shavings or chip rejecting part is inserted in a longitudinal groove of the planer shaft, wherein this chip rejecting part is supported at the groove flank located in front of the planer knife in the direction of rotation and clamps the planer knife against the other groove flank. The chip rejecter has, on its side facing radially outward, a corrugated profile corresponding to the large-volume rusticating cutter profile.
If a mini reversible tip is to be clamped instead of the rusticating planer knife, clamping cannot be carried out exclusively by the clamping wedge, but rather an additional clamping body is needed which clamps itself—and, in so doing, also the mini reversible tip—between the clamping wedge and the outer groove flank.
Clamping wedges of the type mentioned above are complicated to produce and are accordingly expensive. Further, the rusticating knife clamping wedge must be exchanged with standard clamping wedges with a straight chip rejecting part when using straight planer knives because of the corrugated chip rejecting part. This complicates the exchanging of planer knives and, moreover, requires special storage for the different clamping wedges.
The corrugated chip rejecting part is necessary for limiting chip thickness because the maximum chip thickness in rusticating planer knives is appreciably thicker than in straight planer knives. This is because the thinnest chips generated by the corrugation troughs of the cutter must also still have a sufficient thickness for high surface quality. Therefore, the minimum chip thickness in rusticating knives is adapted to the minimum chip thickness of straight planer knives, wherein the maximum chip thickness must be about one millimeter thicker than the minimum chip thickness for the rusticated texture to be visually effective.
Since the risk of a back-kick increases with the chip thickness when working with the planer, the chip thickness is limited to a maximum 1.1 mm.
SUMMARY OF THE INVENTION
The planing machine, planer shaft, planer knife and spacer strip according to the invention have the advantage over the prior art that rusticating planer knives according to the invention can be clamped in the same manner as mini reversible tips in their standard clamping devices, so that there is no manufacturing cost for special outfitting for rusticating knives.
By refashioning series-produced mini reversible tip blanks with a thickness of 1.1 mm and a height of 5.5 mm as rusticating knives, they can be clamped with conventional screw clamping means, but can also be clamped by means of centrifugal force. Due to the fact that the constructional size is reduced by a factor of 10 compared with conventional high-speed steel rusticating knives, carbide rusticating knives can, for the first time, be produced inexpensively with a service life approximately ten-times longer than that of previous rusticating knives. Because of their small dimensions, the rusticating planer knives according to the invention have the advantage over previous large-volume rusticating planer knives that they save considerable weight.
A chip rejecting part for limiting chip thickness can be inserted in an additional, easily produced longitudinal groove of the planer shaft as a plastic strip without increasing weight. Therefore, the planer shafts, according to the invention, with centrifugal force clamping for mini reversible tips are suitable for producing rustically textured workpiece surfaces without resulting in substantially higher production costs than for previous planer shafts for straight dual-cutter mini reversible tips or for other straight planer knives.
A rusticating knife which is particularly simple to produce from mini reversible tips and, in addition, can be positioned radially in a particularly exact manner relative to the planer shaft, and in which changes in position brought about by clamping are eliminated is provided in that the planer knife carries only one effective cutter with corrugation troughs and corrugation crests, wherein the troughs lie on a common first straight line having the same parallel spacing relative to their back groove as straight standard cutters of conventional mini reversible tips relative to their back groove, and the crests lie on a common second straight line which extends 0.5 mm to 1.5 mm above the first straight line, and in that the planer knife carries a flattened contact edge instead of a second cutter at its side located opposite from the first cutter for support at the radial stop of the planer shaft, wherein the parallel spacing of the contact edge relative to the back groove is 0.5 to 1.5 mm smaller than the parallel spacing between the back groove and the opposite corrugation troughs. Therefore, the manual planers according to the invention can be produced more simply, more economically and so as to be more efficient. This advantage is also provided in that the planer knife with the corrugated cutter is 1.1 mm thick, 5.5 mm high and as wide as the planer shaft and is preferably made of carbide.
The planing machine and planer shaft are lighter and can be produced in a simpler manner in that another longitudinal slot is arranged parallel in front of the first longitudinal slot for receiving a spacer strip for limiting chip thickness.
The spacer strip can be arranged at the planer shaft so as to prevent its loss in that the longitudinal slot for receiving the spacer strip has a cross-shaped cross section with at least one shoulder recess. Compared with previous planer shafts, the spacer strip which is made of plastic results in reduced weight because the additional longitudinal slot reduces the mass of the planer shaft more than the spacer strip increases the total mass of the planer shaft.
Due to the fact that the outer edge of the spacer strip projecting over the outer contour of the planer shaft is corrugated and extends along a flight diameter which is 1 mm smaller than the cutter of the planer knife, its function as a chip thickness limiter is ensured. A slot closure which extends flush with the outer contour of the planer shaft and which is alternatively adjustable for limiting chip thickness is provided in that the edge of the spacer strip located opposite from the outer edge with the corrugated contour has a straight contour. Further, the spacer str
Robert & Bosch GmbH
Striker Michael J.
Watts Douglas D
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