The present invention relates to a separating-and support element for a tool holder for a surface milling machine.
Surface milling machines are used for the removal of rubber on runways and of road markings, and for the removal of surface coverings. The Swiss patent no. CH 687 445, by way of example, presents a surface milling machine of a small type. The actual tool holder is mostly constructed as a thread spool, to the flanges of which from two to eight shafts proceeding peripherally and in parallel to the core are generally attached, to which tools, such as small milling wheels, for example, can be mounted in a loose and rotatable manner. If the tool holder rotates, then the tools are externally held to the shafts by means of centrifugal force. If this tool holder is, during the rotary movement, brought near to a surface, the plane of which is positioned in parallel to the axis of the tool holder, then these tools strike on the surface to be processed or, first of all, onto elevations which are possibly present. This impact brings them into a rotating movement. The surface is processed with the force that is to be applied in order to overcome the inertia of the stationary tools. Irregularities are evened out and/or a thin layer of the surface is abraded away.
This impact-like stressing acts on the tools, shafts, tool holder, and drive unit of the surface milling machine. The more that this stressing is absorbed by suitable means, such as tools, shafts, and flanges of the tool holder, the less is the wear on the supports of the drive elements of the milling machine.
In order to additionally cushion the wear on the shafts, the shafts are supported on both of the flanges in a loosely rotatable manner. Frontal covers or other attachment means hold the shafts inside the flanges in which they are supported. The patent no. CH 1998 0067/98 proposes a tool holder of this type. Wear appears on both the tools and the shafts, as well as on the borings in the flanges in which the shafts are held.
In order, in the case of very hard applications, to support the shafts on the periphery of the flanges on which the tools are held, additional intermediate flanges are applied to the central tube, for example, as separating- and support elements. The shafts are thereby reinforced, and their service life is extended. The disadvantage that the positions of the tools on the shafts are predetermined by the flanges acting as separating- and support elements has to be accepted in return, however. If such a surface milling device is, during the milling, guided directly up to a surface, it leaves unprocessed corrugations behind at that point where the intermediate flanges are located. These intermediate flanges, by means of which better wear characteristics can be achieved, have the disadvantage that they act as separating- and support elements and no longer uniformly process the surface over the entire width of the tool holder. Such intermediate flanges are depicted, for example, in patent no. CH 687 445.
This fact is taken into account in other constructions through the fact that separating and support elements are, as so-called flange segments which each support one or more shafts, but not all shafts, however, are welded onto the central tube. These are positioned displaced along the length of the tool holder. By means of these flange segments, the disadvantage of the formation of corrugations is, to be sure, eliminated and the surface processed can be processed uniformly over the entire length of the tool holder, but dynamic disadvantages have to be accepted in return. Such types of tool holders provided with flange segments as separating- and support element must be balanced, since dynamic imbalances otherwise act on the support in a manner that promotes wear.
One additional disadvantage of these separating- and support elements (flange segments) welded solidly to the central tube is the predetermined fixed arrangement in which the tools must be mounted to the shafts. That is to say, it would be desirable for the user if, for individual applications, one pair, or three or more tools, could be mounted in succession one after another.
For applications with special tools, it is worthwhile to use few tools. This is also possible, in the tool holders with separating- and support elements described above, by means of intermediate disks between the tools and between the tools and flanges. In any event, possibilities are geometrically present. If neither intermediate flanges nor flange segments are present, then only a few tools can still be mounted by means of intermediate disks. In that casexe2x80x94because of the large unsupported lengths that arise on the shafts, and the imbalances that always arisexe2x80x94very great force peaks act on individual points of the shafts, and the wear is enormous. Even if separating- and support elements are present in the form of intermediate flanges and/or flange segments, the forces of the dynamic imbalances act on the shafts and support in a highly destructive manner.
The present invention now sets the task of improving the separating- and support elements for a tool holder of the type mentioned above in such a manner that, even if only individual tools are used, the dynamic imbalance of the tool holder still remains within acceptable limits, and the arrangement of the tools can be freely determined at the construction site each time in accordance with the requirements of the specific application.
Separating-and support elements for a tool holder with the characteristics of the present invention solve this task.