Cutting – Cutting motion of tool has component in direction of moving... – Orbital motion of cutting blade
Reexamination Certificate
1999-07-28
2001-06-12
Peterson, Kenneth E. (Department: 3724)
Cutting
Cutting motion of tool has component in direction of moving...
Orbital motion of cutting blade
C083S344000, C083S506000, C083S347000
Reexamination Certificate
active
06244148
ABSTRACT:
The present disclosure relates to the subject matter disclosed in German patent application No. 198 34 104.0 of Jul. 29, 1998, the entire specification of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
The invention relates to a cutting device comprising a machine frame, an anvil drum mounted on the machine frame for rotation about an axis of rotation and having an anvil surface, a cutting tool mounted on the machine frame for rotation about an axis of rotation and having a cutter cooperating with the anvil surface in such a way that in successive rotary positions, respectively successive cutter sections stand in an operative position with successive anvil surface sections in order to cut a material passing through between cutting tool and anvil drum, the cutter being of such construction that different cutting forces occur when different cutter sections cooperate with corresponding anvil surface sections.
Such cutting devices are known from the prior art. The standard procedure with these is that the cutting tool is advanced towards the anvil drum to such an extent that even when the forces required for the cutting are at a maximum an adequate cutting action is still achieved.
However, this solution has the disadvantage that the cutters undergo very great wear in those areas in which lower cutting forces occur, and, in all, the cutting tool has only a relatively short service life.
The object underlying the invention is, therefore, to so improve a cutting device of the generic kind that the cutting tool has as long a service life as possible.
SUMMARY OF THE INVENTION
This object is accomplished with a cutting device of the kind described at the outset, in accordance with the invention, in that the cutting tool and the anvil drum are pretensioned in a direction towards each other with a pretensioning force, in that by means of at least one supporting ring arranged in a rotationally fixed manner relative to the cutting tool, the cutting tool is supported via successive supporting ring sections on successive supporting surface sections arranged in a rotationally fixed manner relative to the anvil drum, and the respectively operative supporting ring section acts on the respectively operative supporting surface section with a bearing force corresponding approximately to the difference between pretensioning force and cutting force, and in that the supporting ring is of such construction in the respectively operative supporting ring section applying the bearing force relative to the operative cutter section corresponding to this supporting ring section that the supporting ring holds the cutter section standing in the operative position at a defined spacing from the corresponding operative anvil surface section with the varying bearing force respectively resulting from approximately the difference between pretensioning force and cutting force.
The gist of the inventive solution is thus to be seen in the fact that the supporting effect of the supporting ring with a bearing force varying inversely to the varying cutting force is to be so adapted to the radial extent of the cutter sections with respect to the axis of rotation that in spite of the varying bearing force, the supporting ring holds the operative cutter sections essentially in a defined spacing range from the corresponding anvil surface sections, the spacing range being selected such that an adequate cutting action still always occurs. This is preferably a spacing range which is in the order of magnitude of less than several hundred micrometers, preferably less than one hundred micrometers.
Here it is to be assumed that the supporting ring, even if it is made of steel, will owing to the bearing force undergo deformation in the radial direction, i.e., that the radial extent of the supporting ring in relation to the axis of rotation will decrease, and the varying bearing force will result in the decrease in the radial extent of the supporting ring not being constant, but likewise varying with the varying bearing force.
These changes in the supporting ring caused by the varying bearing force are, in accordance with the invention, to be brought into line with the cutter.
If, for example, one assumes that the cutter with its cutter edges has an essentially constant radial extent with respect to the axis of rotation, there are several compensation possibilities with an appropriately designed supporting ring, and these possibilities are also usable with cutter edges which do not have an essentially constant radial extent.
One possibility is to impart a varying elasticity to the respectively successive supporting ring sections.
Such a varying elasticity could, for example, be realized by the material elasticity of the supporting ring being of directly varying design, for example, due to changes in material or structure, which can, for example, be realized by diffusing elements into the structure of the supporting ring.
Another possibility consists in imparting to the supporting ring a variable elasticity due to variation of shape. Such a variation in shape makes provision for the supporting ring to be made from material with homogeneous elasticity properties, but for the elasticity of the supporting ring to also be variable by variation of the shape of the supporting ring. For example, it is possible to achieve such a shape elasticity by the supporting ring having a variation in the cross-sectional area with respect to its cross-sectional areas extending perpendicularly to the azimuthal direction.
It is, for example, possible to produce such a variation of the cross-sectional area by providing a supporting ring with a constant cross section and making suitable recesses therein.
A particularly simple possibility of achieving such a cross-sectional variation is for the supporting ring to have a varying shape in a direction transverse to the radial direction and transverse to the azimuthal direction. Such a variation in shape can, for example, be realized by making recesses extending in this direction in the supporting ring, which is otherwise of constant cross section.
Such recesses can be expediently made as, for example, recesses starting from an outer edge and extending transversely to the azimuthal direction.
A further alternative solution enabling, in particular, a direct compensation of the deformation of the supporting ring in the radial direction which varies in accordance with the varying bearing force makes provision for the supporting ring to have a varying radial extent with respect to the axis of rotation. It is thus possible to deviate from the cylindrical surface, for example, due to a flattening or a recess to that extent to which the radial deformation of the supporting ring changes with varying bearing force. For example, the flattening or recess is of such dimensions in the radial direction that this change in the radial direction just compensates the change by which the supporting ring is deformed to a lesser extent when the bearing force changes from the maximum value towards the minimum value.
A further alternative of the inventive solution makes provision for the supporting ring to maintain a homogeneous material elasticity and an unchanged shape, and for the decrease in the deformation of the supporting ring during the transition from maximum bearing force to minimum bearing force to be taken into account by the cutter sections operative at minimum bearing force having a larger extent in the radial direction than the cutter sections with which the bearing force is maximum and the cutting force minimum.
Very different solutions are conceivable for the arrangement and construction of the supporting ring. For example, it is conceivable to provide the supporting ring as a separate ring which sits alongside the cutting tool, but the precision of the supporting action by the supporting ring relative to the cutting tool is then problematic. For this reason, provision is preferably made for the supporting ring to be seated on the cutting tool and for the supporting ring on account of a joint ma
Aichele Werkzeuge GmbH
Choi Stephen
Lipsitz Barry R.
Peterson Kenneth E.
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