US 3596724 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
United States Patent Inventor Appl. No.
Filed Patented Assignee Priority Karl Gunther Bechem Hagen, Germany June 7, 1968 Aug. 3, 1971 J. C. Soding & Halback KG Hagen, Germany June 9, 1967 Germany CUTTING ROLLER 5 Claims, 9 Drawing Figs.
Field of Search .Q.
................................................ EZlb 9/14,
E2lc 13/01 175/327,
References Cited UNITED STATES PATENTS Erickson Voigtlander..... Zublin Baker Bylund Robbins et a1.
Buell McElya et a1 Primary Examiner-David H. Brown Attorney-Owen. Wickersham & Erickson ABSTRACT! A cutting roller for use in rock-boring equipment and having two circumferentially extending parallel cutting ribs. Each rib is provided with a series of wear-resistant exchangeable inserts which protect the crown and flank surfaces of the rib against wear.
- Patented Aug. 3, 1971 5 Sheets-Sheet 1 lnyenlar: K, .G. BECHEM B5 jis i (won/ Patented Aug. 3, 1971 3,596,724
5 Sheets-Sheet 3 Fig. 5
lave/liar: K. e. BECHEM 8: OMIWJWZMA Zi Qiw flit/U Patented Aug. 3, 1971 3,596,724
5 Sheets-Sheet 4 lave/liar:
K. C. E .C H E M Patented Aug. 3, 1971 3,596,724
5 Sheets-Sheet 5 INVENTOR.
K. C. BE C H E M BY 4a,, MW
ATTORNEYS CUTTING ROLLER BACKGROUND OF INVENTION The invention relates to a cutting roller or bit for use in rock-boring equipment, of the type having at least one circumferentially extending cutting rib.
SUMMARY OF INVENTION It is an object of this invention to provide a cutting roller of this type, having a working life which is greater than has hitherto been attainable.
According to the present invention, the or each cutting rib is provided around its periphery with a series of exchangeable inserts of wear-resistant material, each insert being received within a recess and having working edges which are flush with or extend beyond the crown and flank surfaces of the rib with which it is associated.
The inserts, having greater wear-resistant properties than the ribs, ensure that the crown and flanks of the ribs are protected against wear. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shown a cutting roller provided with two cutting ribs, viewed in the radial direction;
FIG. 2 shows an axial partial section showing the ribs of the roller of FIG. I, with the roller in the working position and shown inclined to the borehole axis;
FIG. 3 shows an axial partial section through a cutting rib and insert prior to the fixing of the insert in its recess;
FIG. 4 shows a section taken on the line IV-IV of FIG. 3;
FIG. 5 is a view similar to FIG. 4 but shows a different embodiment of insert;
FIG. 6 shows a further embodiment of insert;
FIG. 7 is an axial section through a further embodiment of cutting roller;
FIG. 8 is a fragmentary view of a portion of cutting roller like that of FIG. 7 but somewhat modified; and
FIG. 9 is a view similar to FIG. 3 of a modified form of insert flush with the rib. DESCRIPTION OF PREFERRED EM- BODIMENTS The cutting roller represented in front elevation in FIG. 1 has a roller body R, whose outer periphery is provided with two parallel circumferentially extending cutting ribs 1. Fastened in each of the cutting ribs 1 is a series of circumferentially spaced radially projecting highly wear-resistant inserts 3, for example, made from carbide, preferably of sintered double carbides. The inserts 3 have, when considering sections taken radially through the tool body R and containing the axis thereof, cross-sectional profiles which correspond approximately to the profile of the cutting ribs 1, but which project somewhat beyond the flanks of the ribs and beyond the crown surfaces. If the working surfaces of the inserts, in the case of a new cutting roller, are flush with (FIG. 9) or extend beyond (FIG. 3) the surrounding material of the roller body, the material of the roller body present in the outer layer in the region of the inserts can, under the action of the pressure occurring during cutting or boring, also be compressed and thereby strengthened. By means of the shape of the inserts, the wearing zones on the cutting ribs I which are denoted by reference characters a, b and c in FIG. 1 are respectively protected by each individual insert.
The protection of the wearing zones on the cutting ribs by the inserts 3 is clearly shown in FIG. 2. In this figure the inserts 3 consisting of highly wear-resistant material are seen to be inserted radially into the cutting ribs and fastened in the ribs such as to project outwardly beyond the material at the crown and two flank surfaces of the cutting rib 1 which are subject to wear.
The method of operation of the tool is apparent from FIG. 2. The cutting roller R is rotated about an axis which is inclined downwards with regard to. the borehole axis, which axis is located to the right of FIG. 2. The rock forming the borehole bottom 2 of the bore is thereby undercut and stripped in steps as soon as the cutting ribs 1 armed with the inserts 3 have penetrated, for instance by the extent d. The new bottom of the borehole then extends approximately on the line 4. Since the cutting ribs and the highly wear-resistant inserts are comparatively narrow as compared with the width of the borehole 2, a favorable relationship between stripped and ground rock emerges.
In accordance with FIGS. 3 and 4, the inserts 3 are arranged in the cutting ribs 1 in recesses 5, which are formed initially with greater cross-sectional dimensions than the corresponding dimensions of the inserts. The cross section of each insert increases from its working surface to its root 3a. In one method, the fastening of the insert 3 in the recess 5 is effected by displacing, tamping, pressing or otherwise deforming the material of the cutting rib bordering the recess 5 against the insert in the direction indicated by arrows in FIG. 3. In this way the insert is effectively embedded until the insert itself and the cutting rib in which it is embedded are completely worn away.
Similarly, as shown in FIG. 4 the insert 3 is safeguarded against stresses acting axially of the roller. The section tangential to the cutting roller represented in FIG. 4 on the level of the line IV-IV of FIG. 3 shows that central portion 3b of the insert is thicker than the portions lying close to the flanks of the cutting rib. If, therefore, the material of the cutting rib is displaced against the insert 3 in the direction indicated by the arrows in FIG. 4, the insert is safeguarded against stresses acting axially of the roller, i.e. transversely of the rib.
It is known that, upon boring, large transverse forces acting radially of the borehole are applied to the inserts. These forces can, depending on the rock to be bored, be directed radially outwardly or inwardly of the borehole. Frequently forces directed radially inwardly occur, because particularly those inserts running on the greatest radius with their outwardly lying working surfaces on the borehole wall meet on their outer surface a greater resistance than the more or less exposed inner working surfaces.
In the case of hard rock, in which the working surfaces turned to the borehole center are almost entirely exposed, forces occur which seek to tilt the inserts inwardly about their tip. By this means, forces directed inwardly radially of the borehole also arise. On the other hand, in the case of soft, possibly viscous rock, it can happen that the resistances which act on the two lateral working surfaces of an insert are approximately of equal magnitude. Then the insert tends, with the cutting roller axis tilted, to give way radially outwardly, so that correspondingly directed transverse forces have to be absorbed by the anchorage.
In order to increase the effectiveness of the fastening of the inserts against transverse forces active in one direction only, the inserts can instead have the cross-sectional shape shown in FIG. 5. The insert 3c represented in a section tangential to the cutting roller (which corresponds with that in FIG. 4) tapers towards the lateral working surface at the bottom of the figure more sharply than towards the other working surface lying at the top in the figure. More material of the roller body can thereby be displaced into the recess 5 in the regions 5a than in the remaining regions. The insert 3c is therefore particularly reliably safeguarded against transverse forces which seek to displace it towards the bottom or the figure.
A safeguard against the transverse forces directed radially of the borehole which occur upon boring can be achieved by means of the insert represented in FIG. 6. In FIG. 6, the insert 3 is provided on its root side with an extension 3a projecting into the roller body. The recess receiving the insert 3 is correspondingly depressed to receive the extension 3d. The insert is, in this way, effectively locked in position against such transverse forces directed radially of the borehole, and these forces acting on the insert 3 are thereby transmitted to the roller body. The extension 3d can be rounded or sharp-edged in profile.
As previously described, the inserts can be fastened in position in their respective recesses by displacing the material bordering on the recesses 5 against the side faces of the inserts by externally applied foreces. In this way, compression and thereby strengthening of the material of the rib is obtained. This compression increases during boring, because of the forces acting on the ribs during the boring operation.
Alternatively, the inserts may be bonded in position in the recesses, by soldering, welding or the use of an adhesive, so as to be exchangeable or replaceable. At the beginning of boring, the material of the roller body is displaced into the still open recesses and compressed in the regions bordering on the inserts. Synthetic resins are available which act as adhesives and which have strength properties which are not inferior to those of steel. These adhesive materials have the further advantage of being comparatively elastic, so that, when used to bond the inserts in position, they can be used to accommodate the effects of shocks, which act to an extraordinarily high degree on the cutting ribs and inserts when working in rock. Irrespective of whether the adhesive properties of synthetic resins of the above-mentioned type are exploited or not, the arrangement of elastic layers supporting the inserts can be extremely advantageous as shown in FIG. 7. In FIG. 7, the roller body R has ribs 1 which receive inserts 3 having wedgeshaped projections 3f to ensure positive connection. Opposite them there are corresponding working surfaces. An elastic layer 6 of synthetic resin is also provided, which may, if desired, act as the sole connection means, cementing the adjoining parts together. lfan alternative means of connecting the parts is employed as is FIG. 8, the synthetic resin layers 6 and 7 merely have the task of forming an elastic intermediate layer which cushions the shocks encountered in use and at least partly converts them in an elastic type of deformation. It is also possible to provide an elastic intermediate layer of this kind in the shape of members, for instance a conical bush 8, between the shaft 9 and the main body part S of the roller. This in no way exhausts the possibilities for employing elastic intermediate layers of this kind, which can be provided wherever they are able to develop the specified advantageous and other effects. These further advantages consist in a substantial increase in the life of the tool not only because, through the cushioning of the shocks a good protection of the inserts consisting of wear-resistant materials ensues, but above all, because the useful life of the mounting itself is increased. In this respect, to be understood by "wear-resistant" materials are those which are more wear-resistant than the material surrounding them.
When the inserts are bonded in position by an adhesive or by solder from which the insert is readily releasable, the inserts may be easily replaced after they have sustained a given amount of wear.
By virtue of the installation of the resilient connecting elements, in operation each cutting roller is essentially stressed tightly independently of the support for the body.
An important feature is the arrangement of the cutting teeth consisting of tungsten carbides between the other teeth of the cutting rollers, which are intended to produce large holes, furrows, trenches and tunnels in rock, whereby it is thus a question of drilling, cutting and milling work. The wear-resistant inserts protect the lateral flanks and the crown surfaces of the teeth consisting of the base material of the cutting rollers, so that the useful life of the cutting, boring and milling tools is increased several times.
To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.
1. A cutting roller for use in rock-boring equipment and comprising at least one circumferentially extending rib having an axially flattened crown surface lying between two sloping flank surfaces and being formed with a series of circumferentially spaced recesses in said crown and flank surfaces, and
a plurality of inserts of wear resistant material, each insert having a crown surface between two flank surfaces and being received within a respective said recess and having its said crown and flank surfaces respectively extending out at least as far radially as the crown and flank surfaces of the rib,
each said recess having substantially planar parallel axial walls and a flat bottom wall, and the cross section of each insert increasing from its working edge toward its root and having a rounded bottom surface at its root,
whereby the material of said rib can, under the action of the pressure occurring during cutting, be compressed and thereby strengthened. 2. A cutting roller as claimed in claim 5 wherein the inserts have convexly curved side surfaces, with one side surface substantially larger than the other and are curved on the axially extending sides.
3. A cutting roller for use in rock boring equipment and comprising at least one circumferentially extending rib having an axially flattened crown surface lying between two sloping flank surfaces and being formed with a series of circumferentially spaced recesses in said crown and flank surfaces, and g a plurality of inserts of wear-resistant material each insert having a crown surface between two flank surfaces and being received within a respective said recess and having its said crown and flank surfaces respectively extending out at least as far radially as the crown and flank surfaces of the rib,
each said recess having substantially planar parallel axial walls and a bottom wall, the inserts having convexly curved side surfaces, with one side surface substantially larger than the other and being curved on the axially ex tending sides,
having in each of said recesses a central depression, and said inserts each having a central rounded projection received in said depression, so that each insert is held in a formlocking manner, so that forces applied during use to the inserts are absorbed by the roller.
4. A cutting roller for use in rock-boring equipment and comprising at least one circumferentially extending rib having an axially flattened crown surface lying between two sloping flank surfaces and being formed with a series of circumferentially spaced recesses in said crown and flank surfaces, and
a plurality of inserts of wear-resistant material, each insert having a crown surface between two flank surfaces and being received within a respective said recess and having its said crown and flank surfaces respectively extending out at least as far radially as the crown and flank surfaces of the rib,
each said rib being an annular member and being resiliently supported on a sleeve of said roller, which in turn is resiliently supported on a conical bush, each resilient support being by means of elastic layers,
whereby the material of said rib can, under the action of the pressure occurring during cutting, be compressed and thereby strengthened.
5. A cutting roller as claimed in claim 4, wherein other elastic layers also bond the ribs to the roller.
32 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 3 596 724 Dated Agggs; 3 192 1 Karl Giinther Bechem Patent No.
Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Col. 3, line 2, "foreces" should read forces line 28, "is" should read in Col. 4, line 20, "5"
should read l Signed and sealed this 28th day of March 1972.
EDWARD M.FLETUHER, JR. Atteating Officer ROBERT GOTTSCHALK Commissioner of Paten ts