Cutting tooth for earthworking

Details Cutting tooth for earthworking Cutting tooth for earthworking

1998-11-12

2001-08-07

Bagnell, David (Department: 3673)

Mining or in situ disintegration of hard material

Cutter tooth or tooth head

Endless-chain type head

C299S108000, C299S11200T, C037S465000

Reexamination Certificate

active

06270164

ABSTRACT:

RELATED APPLICATIONS
This application claims priority from German Utility Model Application No. 297 20 261.8 filed Nov. 14, 1997, which is incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates to a cutting tooth to be fitted in a cutting-tooth holder of an earthworking appliance.
Such an earthworking appliance may, for example, be a cutting wheel or a cutter chain which is used, in civil engineering, in diaphragm wall cutting appliances for producing diaphragm walls. The cutting teeth in each case comprise tooth root and cutter and are fitted on the earthworking appliance with the aid of cutting-tooth holders.
During operation, the cutting teeth are moved in the cutting direction, i.e. in the circumferential direction of the cutting wheel or in the running direction of the cutter chain. On the flank which faces in the respective direction of movement, the cutting teeth therefore have a cutter. On the one hand, the cutter penetrates into the earth lying in front of it in the particular cutting direction, and on the other hand the actual cutting advance is achieved by moving the cutting wheel or the cutter chain in the plane of rotation of the cutting wheel or of revolution of the cutter chain. The advance side, which faces in the direction of advance, of the cutting tooth is thus pressed against the earth in accordance with the cutting advance.
BACKGROUND OF THE INVENTION
DE-U 87 15 141 has disclosed a cutting tooth which, on the flank facing in the cutting direction, has a cutter which is mounted ahead of a cutter-support region, as seen in the cutting direction. The cutter axis is inclined slightly in the cutting direction. On the advance side, which faces in the direction of advance, the cutter-support region is flush with one end of the cutter, and in the area lying in the opposite direction to the cutting direction, is drawn down toward the tooth root by way of an arch which is slightly convex when seen from the side.
As a result of the cutting advance component of the movement of the cutting tooth, that edge of the cutter which faces in the cutting advance direction and the adjoining part of the cutter-support region are pressed against the earth and consequently are gradually ground down to assume a flatter shape. In the process, a surface which has been ground down essentially perpendicular to the cutting advance direction is produced in this part of the cutter-support region. Since the cutter-support region is drawn down toward the tooth root in the opposite direction to the cutting direction, this surface increases in size as the cutting tooth becomes increasingly worn. The result of this is that the cutting advance becomes ever more difficult as the wear to the cutting tooth increases, since an increasingly large “blunt” surface has to be pressed against the earth. In the cutting advance direction, only the outer edge of the cutter, as seen in the cutting direction, has a cutting function. The adjoining surface is pressed flat against the earth.
SUMMARY OF THE INVENTION
The invention is therefore based on the object of designing a cutting tooth which is to be fitted in a cutting-tooth holder of an earthworking appliance and has at least one cutter mounted ahead of a cutter-support region, as seen in the cutting direction, in such a manner that it allows an effective cutting advance combined with a simple design even with a ground-down advance side facing in the cutting advance direction.
This object is achieved for a cutting tooth of the generic type by the fact that the size of the cross-sectional areas of the cutter-support region which run perpendicular to the cutting advance direction and intersect the at least one cutting edge remains approximately constant in at least one area which is delimited by in each case two such cross-sectional areas.
As a result, while maintaining a simple design of the cutting tooth, the advance side, which is pressed against the earth, of the cutting tooth is not significantly increased in size when the cutting tooth has been ground down to such an extent that it has a cross-sectional area which remains approximately constant as the wear continues.
Consequently, a basic principle of the invention consists in providing the cutter-support region with a shape in which, in the individual cross-sectional planes parallel to the advance side, length and width are adapted to one another and depend on one another in such a way that the surfaces are identical in all the cross-sectional planes.
As a result of the cutting advance conditions being facilitated, the cutting tooth according to the invention leads to considerable savings on energy since the force which is to be applied in order to advance the cutter does not, as was previously the case, increase substantially as the level of wear increases. Furthermore, there is a considerable saving on materials, since the cutting tooth according to the invention only has to be replaced after a considerably greater level of wear has taken place. Furthermore, the cutting tooth according to the invention is extremely simple to produce.
According to an advantageous embodiment, the cutter-support region has, on the advance side, a step which is directed approximately parallel to the at least one cutting edge, the cutter-support region, which is oriented in the opposite direction to the cutting direction, being drawn down toward the tooth root. If, as a result of wear, the cutting tooth is ground down to as far as this step at its edge of the step which lies toward the cutting advance direction, the cross-sectional area running perpendicular to the cutting advance direction, on the advance side of the cutting tooth, is not increased in size during further use of the cutting tooth until the cutting tooth has been ground down over the entire height of the step. This step, which is extremely simple to produce, therefore results in extremely good conditions for the cutting advance.
According to a further advantageous embodiment, the cutter-support region has an elongate indent, which runs in the cutting direction, in the region of each of the side flanks. Therefore, a web which runs longitudinally in the cutting direction remains between these two indents. This measure too results in that surface area of the ground-down cutting tooth which is to be pressed against the earth increasing only slightly as the level of wear increases. When the surface of the cutting tooth reaches those ends of the indents which lie in the cutting direction, the cutting-tooth surface limit which lies in the opposite direction to the cutting direction merely moves along the steeply falling limit line of the indents which lies in the cutting direction and along the web. The width of the web is clearly considerably less than that of the overall cutting tooth, so that it contributes to the surface of the cutting tooth only to an insignificant extent. The advantageous embodiment presented here results in a very efficient level of support for the cutter-support region lying in the cutting direction and for the cutters despite the indents.
Good results are achieved if the indents continue to as far as that side of the cutting tooth which lies in the opposite direction to the cutting direction. As a result, its resistance as the cutting tooth moves in the cutting direction is kept very low.
An alternative advantageous embodiment consists in providing an indent in the cutter-support region over the entire width of the side facing in the cutting advance direction and in designing the side flanks in the form of a wedge, in such a manner that they are directed toward one another, in the form of a wedge, in the opposite direction to the cutting direction. As a result, in cases in which the support of the cutter-support region facing in the cutting direction and of the cutter in the cutting direction is not critical, it is possible to avoid an increase in the force required for the cutting advance movement in a particularly effective manner.
In this embodiment too, the indent is advantageously continued to as far as th

Affiliated with

Also associated with

Rating

Cutting tooth for earthworking does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Cutting tooth for earthworking, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cutting tooth for earthworking will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2457760