US2033594A - Scarifier tooth - Google Patents

Description

March 10, 1936.

's. M. sToopY SCARIFIEEAIUTTOOTH Filed Sept. 24, 1951 2 Sheets-Sheet l IP75. Z.

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AT TUENEYS- March 10, 1936. s. M. STOODY SCARIFIER TOOTH Filed Sept. 24, 1931 2 Sheets-Sheet 2 NVENTUE- ,3. .SOd

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Patented Mar. 10, 1936 UNITED STATES PATENT OFFICE SCARIFIER TOOTH tion of California Application September 24, 1931, Serial No. 564,858

'7 Claims.

This invention relates to improvements in scarifying teeth, such as those used upon road scrapers, rooters, steam shovel buckets, and analogous constructions.

. It is becoming common practice to apply pieces of a hard abrasive substance to the forward sides of scarifier teeth used on road scrapers, rooters, steam shovel buckets and the like. Such pieces for example may be tungsten carbide or their equivalent and are frequently applied to the tooth by means of a welding rod, such as is disclosed in United States Letters Patent Nos. 1,757,601 and 1,803,875, wherein the pieces of tungsten carbide are enclosed within a mild steel tube. During the welding operation the mild steel tube forms a matrix metal deposited on the body of the tooth and fused thereto in which the pieces of abrasive are embedded. When conventional forms of scarifier teeth have this hard facing applied thereto several difficulties are frequently encountered. Many types of scarifier teeth are either circular or rectangular in cross-section or may have other shapes which provide a relatively thick body of steel having on its forward face the deposit of matrix metal containing the hard abrasive pieces. These teeth are frequently sharpened to a chisel point in their initial construction and if they are of other designs they frequently have a relatively thin bottom edge. When they start to cut, the chisel point or thin edge frequently becomes red hot, due to friction, and the steel body near the point approaches a forging temperature. The heat softens the steel sufficiently so that the pieces of tungsten carbide, or other hard abrasive, on the thin edge or chisel point are forced or carried rearwardly through the softened metal. These pieces on the point, therefore, become lost without having accomplished a great deal of cutting. Following this action in which the point or thin edge is quickly worn, there usually is a short period of fairly good wear and good cutting. Theoretically as the body of the scarifier tooth is formed of steel, which is much softer than the pieces of tungsten carbide, it should wear away faster than the tungsten carbide and cause the scarifier tooth to be self-sharpening. However, when the scarifier tooth is cylindrical in form or has a rectangular cross-section, or has a relatively thick body of other shape, the large mass of steel behind the deposit of abrasive is too large to be worn away fast enough to accomplish the self-sharpening action. Consequently it frequently occurs that this relatively large body of steel behind the abrasive is worn into a rounded heel on the bottom of the tooth. When the rounded heel is formed it merely rubs and prevents cutting. A great deal of friction is created and the tooth has a tendency to chatter. The pieces of tungsten carbide under these conditions cannot cut effec- 5 tively and instead of being worn off are frequently knocked off and lost.

It is an object of the present invention to provide an improved scarifier tooth having a protecting hard abrasive substance onits forward side and which is so designed that the formation of the rounded heel is effectively prevented. In this way the body of the tooth is caused to wear away practically uniformly at a rate faster than the hard abrasive substance wears. As a result, the rounded heel does not form and the scarifier tooth is self-sharpening. The chattering of the tooth is prevented and the length of life of the tooth is materially prolonged in that each piece of abrasive is caused to wear away completely without being subject to the danger of being knocked off and lost.

Another object of the invention is to provide a scarifier tooth, or analogous construction, which has an initial sharp point so designed that the pieces of tungsten carbide on the point will be efiectively backed by steel so that they cannot be forced through the steel and lost.

It has been proposed to design a scarifier tooth for road scrapers and analogous constructions in which the tooth has a body somewhat similar to the conventional plow. When a tooth of this design has a hard facing applied to its forward face, only a relatively small period of satisfactory wear is possible. This is due to the fact that the body of the tooth is not of uniform cross-sectional shape and area. It gradually increases in size and shape from bottom to top of the scarifying end. Consequently when the tooth becomes badlyworn, the upper portion of the body being larger and thicker is apt to wear into the form of a rounded heel with the incidental disadvantages above mentioned. In such construction whenever the scarifying endof the tooth becomes badly worn it is necessary to either rebuild the tooth or to junk it. The designs of such type of teeth also are disadvantageous in that the bottom of the body is usually too thin to prevent the pieces of tungsten carbide from being carried through the steel when heated to a forging temperature.

Another object of the present invention is to provide an improved scarifier tooth which is of uniform cross-sectional shape and area so that its cutting action and wearing action will be identical throughout the complete scarifying end 55 of the tooth. In other words the cutting and wearing of the tooth will be substantially the same when the tooth first starts cutting as when it has become badly worn.

Another object of the invention is to provide a scarifier tooth, the scarifying end of which is substantially V shaped in cross-section, having a hard abrasive material mounted on the apex thereof and having protective side facings extending rearwardly on the sides of the scarifying end. These side facings not only protect the body of the tooth. preserving a good support for the abresive on the apex, but they also serve to form sharp edges on the bottoms of the sides of the tooth which will facilitate penetrating, that is the entering action of the scarifier tooth into the road or the formation as the case may be.

Still a further object of the invention is to provide a novel construction of scarifier tooth or steam shovel bucket tooth having an abrasive mounted on the forward side of the tooth and to provide a novel construction assisting in anchoring the abrasive to the tooth so that it cannot be easily knocked off.

With the foregoing and other objects in view, which will be made manifest in the following detailed description, and specifically pointed out in the appended claims, reference is bad to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Fig. 1 is a side elevation of a scarifier tooth such as is employed on road scrapers embodying the invention, parts being broken away'and shown in vertical section.

Fig. 2 is a sectional view taken substantially upon the line 22 upon Figure 1.

Fig. 3 is a view similar to Figure 1 illustrating a slightly modified form of scraper tooth.

Fig; 4 is a sectional viewsimilar to Figure. 2 illustrating a slight modification.

Fig. 5 is another view in side elevation of another modification, parts being broken away and shown in vertical section.

Fig. 6 is a sectional view illustrating a detail of construction which may be employed.

Fig. 7 is a partial perspective view illustrating another modified form embodying the invention.

Fig. 8 is a sectional view through a steam shovel bucket illustrating the invention as having been incorporated in a steam shovel bucket tooth.

Fig. 9 is a sectional view through the steam shovel bucket tooth.

Referring to the accompanying drawings, wherein similar reference characters designate similar parts throughout, the scarifier tooth illustrated in Figure l is of the double ended type, either of which ends may be employed. It consists of a shank l0 having an upper scarifying end II and a lower scarifying end 12. The lower scarlfying end, which is the one being used, extends downwardly and forwardly a considerable distance from the lower end of the shank so that it encounters the horizontal, forming an angle of approximately 48 therewith. This angle may vary under different circumstances but preferably is between 35 and 55 degrees. As clearly shown on Figure 2, the scarifying end is V shaped in cross-section having rearwardly divergent sides 13 and I4 defined from each other by a groove I5 which extends the complete length of the scarifying end. On the apex or forward side of the tooth there is formed a groove IS within which there is deposited as by welding a relatively heavy deposit of hard facing or abrasive II. This deposit is preferably produced by using a welding rod as disclosed in prior United States Patents Nos. 1,757,601 and 1,803,875. Any other suitable manner or suitable abrasive may be employed if so desired. When the mentioned welding rod is used, a mild steel matrix is deposited in the groove 16 in which particles of a hard substance; such as tungsten carbide indicated at I8, are embedded. This deposit extends upwardly the complete length of the scarifying end and the facing preferably continues a short distance up on the forward side of the shank as indicated at l 9. In the preferred form of construction a relatively thin facing 20 extends rearwardly along the sides l3 and M. This facing may extend entirely to the rear end of each side l3 and M but this is not essential and the side facings 20 may extend only partially over the sides l3 and I4 as shown. It will be noted that the body of the scarifying tooth provides a certain thickness of steel behind the heavy forward hard facing at IT. The thickness of the steel at this point is much less than the overall width or depth of the scarifying end. Likewise the thickness from front to back through the sides l3 and I4 is approximately equal to the thickness of the tooth between grooves l5 and l 6 so that there is practically a uniform thickness of steel behind the hard facings I1 and 20. With this construction the tooth tapers forwardly and has a very hard abrasive forward edge on the apex. As the back of the tooth is removed in forming the groove I5, there is no large body of steel behind the abrasive in groove 16 to form the rounded heel. Wear of the body of the tooth is practically uniform both at the center of the tooth and over the sides l3 so that the tooth will be in effect self-sharpening, wearing away faster than the hard facings l1 and 20. Each scarifying end is uniform in cross-sectional shape and area from bottom to top so that there will be substantially the same cutting and wearing action taking place when the scarifier tooth is originally used as when it has become badly worn. The thick backing behind the very bottom of the hard facing I1 is sufficient to prevent pieces of tungsten carbide from being driven through the body and becoming lost even in the event that the tooth becomes red hot during use. As the body of the tooth can wear away equally behind the side facings 20, these side facings will form sharp edges on the sides of the tooth which facilitate penetration or the entering of the tooth into the road.

In the modification shown in Figure 1, when one scarifying end is completely worn away, the tooth can be reversed to use the other scarifying end. Some forms of road scraping machines, however, are so designed as to be incapable of using a double ended tooth and for this purpose a single ended tooth as shown in Figure 3 is provided, having a shank 25 and a single scarifying end 26, which is of the same construction as that previously described in conjunction with scarifying end l2. scarifying tooth may be straight. Such a tooth is indicated in Figure 5 having a straignt shank 30 in alignment with the two scarifying ends illustrated at 3| and 32. These scarifying ends are likewise similar to the scarifying end I 2.

As a modified form of construction, there is illustrated in Figure 4 the cross-section of a scarifying end which is V shaped having a center portion 35 in the apex of which there is provided a groove 36. This groove is filled with a hard facing 31 similar to the hard facing 11. However, this construction is shown as having the side In other types of machines the facings omitted. It is possible under certain conthan facing I! this facing wears away somewhat faster than facing l1 and will bring about a uniform even wear of the tooth.

- In certain forms of construction the tooth must be very heavily faced. This is particularly true when the tooth happens to be quite large. For this purpose the scarifying end is given a V shape cross-section illustrated at on Figure 6 and on the apex there are formed a series of relatively deep grooves 4|. These grooves .are shown as being deeper than they are wide. Additional grooves 42 may be formed on' the sides which are somewhat shallower. These grooves are filled with the hard facing 43 and a coat or layer of the hard facing may be applied to the sides and over the apex. The purpose of this construction is as follows. If groove I6 is too large it is possible for the facing to be knocked out or gouged out of the groove in doing very heavy work. Where the construction illustrated in Figure 6 is employed, the hard facing may be broken off but because of the very deep grooves the hard facing cannot be completely removed therefrom. Consequently even in the event that the hard facing is chipped away some hard facing remains to cut effectively.

The large areas on the sides of the grooves likewise greatly facilitate the forming of a good adhesive bond between the deposit and the body of the tooth.

In Figure 'I there is illustrated another form of construction designed for heavy work. In this construction the tooth has a V shaped scarifying end, the apex having a groove 45. Pins 46 are cast integral with the body of the tooth and are deposited within thisgroove. These pins may be arranged in a row or may be staggered. Smaller pins 41 may be cast on the sides. When the hard facing is welded on it is welded around these pins and over them. Their presence assists greatly in anchoring the hard facing to the tooth.

In Figures 8 and 9 the invention is illustrated as having been incorporated on a tooth for steam shovel buckets. A conventional steam shovel bucket is indicated at 50 having teeth applied thereto, each tooth having a shank 5| which is bifurcated as indicated at 52- Bolt holes 53 permit the insertion of bolts 54 for attaching the tooth to the bucket. The scarifying end of the tooth extends downwardly and forwardly and is V shaped in cross-section. The scarifying end indicated at'55 is illustrated as beingof the same construction as the scarifying end l2. However,

it may be of the design illustrated in either Figure 4, 6 or 7, if desired. It hasbeen found that a steam shovel bucket tooth constructed in the manner illustrated lasts materially longer than the conventional steam shovel bucket teeth now in general use. Furthermore the end of the tooth remains sharp due to the self-sharpening action which is taking place during wear. This scarifying end of the steam shovel bucket tooth is likewise of uniform section throughout a substantial portion of its length to cause the wear to be uniform and'to prevent the formation of a rounded heel during any period of its wear.

While the various forms of construction illustrate the tooth as having a groove on its apex, the

presence of the groove is not absolutely essential. In some instances the groove may be omitted and merely a heavy coating of hard facing applied to the apex. The groove is preferable, however, due to the fact that it facilitates welding the hard facing onto the tooth and also has the tendency to prevent the hard facing from being knocked off.

Various changes may be made in the details of construction without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:

1. A scarifler tooth for road scrapers and the like having a scarifler end of uniform cross-sectional shape and area, the center of the scarifying end being arrangedjoremost, and the sides ex tending rearwardly therefrom, the front to back thicknesses of the center and the sides being approximately equal, pieces of a hard abrasive mounted in a groove on the forward side of the center portion, and 'a coating of abrasive extending partially toward the rear of the sides, said coating being thinner than the pieces of abrasive in the groove.

2. A scarifler tooth having a, series of grooves on its forward side, at least some of the grooves being deeper than wide, and a hard abrasive substance filling said grooves.

3. A scarifier tooth having projecting pins on its forward side, and an abrasive substance deposited over and around said pins so as to be anchored to the tooth thereby.

4. A scarifier tooth having a longitudinally extending groove'in its leading edge, wearing material in said groove and on those faces of the tooth which are adjacent the groove, said wearing material comprising tungsten-carbide particles and a binder integrally fused to the tooth.

-5. A scarifler tooth or the like comprising a longitudinally extending body having forwardly converging sides converging toward its center, there being a plurality of longitudinally extending grooves formed in the body on the forward side thereof between the forwardly converging sides, and a protective facing comprising pieces of a hard substance such as tungsten carbide .embedded in a matrix metal filling the grooves, the matrix metal being fused tothe body of the tooth.

6. A scarifier tooth or the like comprising a longitudinally extending body having forwardly converging sides converging toward its center, there being a plurality of longitudinally extending grooves formed in the body on the forward side thereof between the forwardly converging sides, and a protective facing comprising pieces of a hard substance such as tungsten carbide embedded in a matrix metal filling the grooves, the matrix metal being fused to the body of the tooth,

the facings in adjacent grooves being connected forward side of the body between said forwardly 'canverging sides, and a protective facing filling said groove and extending rearwardly on the forwardly converging sides, said facing comprising a hard substance embedded in a matrix metal, the matrix metal being fused to the body of the tooth.

SHELLEY M. STOODY.

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