US2369285A - Dipper tooth - Google Patents

Description

Feb. 13,1945.

A. W. DANIELS ET AL DIPPER TOOTH 4 Sheets-Sheet 1 Filed May 1, 1943 INVENTORS Feb.13, 1945. M L ETAL 2,369,285

DIPPER TOOTH Filed May 1, 1945 4 Sheets-Sheet 2 q/Zga Feb. 13, 1945. A. w. DANIELS ETAL DIPPER TOOTH Filed May 1, 1945 4 Sheets-$heet 5 Viz i112 [W 2 3 Feb. 13, 1945'. A w, 'DAMELS ET AL 2,369,285

PPPPPPPPP TH Filed May 1, 1943 4 Sheets-Sheet 4 Patented Feb. .13, 1945 Joseph P. Murtaugh, Oak Park, 111., assignors to Daniels-Murtaugh, Company, Cedar Rapids,

Iowa, a partnership Application May 1, 1943, Serial No. 485,272

1111 Claims. (o1. 37- 142) The teeth of steam shovel dippers and other power driven excavating implements wear down with surprising rapidity in spite of the fact that they are made of tough manganese steel and are hardened by the pounding which they receivein service. The abrasive nature of the service to which they are subjected is so severe that replacementoi the teeth is a substantial item in the cost of running an excavating implement.

For many years, it has been recognized that wear. They have tended to wear rounded along the bottom front edge until very soon the teeth would act like runners of a sled and. ride up on wFig. 2 is a side Fig.1; Fig. 3 is a fragmentary vertical sectional View taken. approximately on the line 3-3 of Fig. 1;

Figs. :4, 5 and 6 are side views of modified forms view of the structure shown in of1the rep1aceable points; i

the difiiculty arose not only from the amount of i wear but the shap to which the teeth would i stay sharp until it is worn back to the point A where repointing becomes desirable. Without turning the teeth upside down, they will last considerably longer than previous teeth even when the latter were turned upside down, and

during their entire life, they will be muchmore satisfactory than previous teeth. In fact, they may even be sharper almost to the end of their life than conventionalteeth when they. are new.

In general, this result is accomplished by providing a shape which, although providing adequate strength, causes the tooth to wear flat instead of rounded on its bottom front edge.

At the same time, this new shape facilitates welding new points to the old tooth, saving both time and welding rod. This results from the fact that the channel formed in the bottom of the tooth in order to balance the wear and produce the flat bottom or self-sharpening wearing effect Fig. 7 is a bottom view of the point shown in Fig. 6;, illustrating, however, optional features of shape for all 01 the illustrated points;

. Figs. 8, 9, 10 and 11, are views illustratinga modified form of the invention, Figs. -8 and 9 being perspective views showing the repointed. H

tooth respectively right side up and upside down, and Figs. 10 and 11, respectively, being side and bottom views of therepointer; l l

. Figs. 12, 13, 14 and 15 are viewsof another form of the inventioncorresponding respectively to Figs. 8 to 11;

Fig. 16 is a perspective view showing drag-line bucket equipped with teeth embodying the presentinvention, some; of them having been repointed.

Several forms of the invention have been chosen for illustration and description, in compliance with- Section 4888 of the Revised Statutes, but persons; skilled the art will. readily perceive other meansfor accomplishing the same results, and th claims are therefore to be construed as broadly as possible, consistent with the prior art.

' teeth maybe removably secured as illustrated or they may be ofany form. The particular form e illustrated is one including a body portion I2 need not be welded and intact forms a clear H demarkation to show the welder where to weld and where not to weld.

In one form of the invention, the repointer and the base portion of the tooth are provided with interfitting V-type parts which accuratelyposition the tooth for welding so thatthe teeth will be properly alinedin their digging function.

Additional objects and advantages of the invention will be apparent from the following de scription and from the drawingsin which:

Fig. 1 is abottom view of the embodiment of the invention chosen for illustration of the form. thereof at present preferred;

havingits upper and lower faces converging toward the point, and a shank portion I3 provided with a key slot l4 through which a key 15 (Fig.

The body portion includes wings l6,

sides. The base should be complementally shaped with clearances everywhere except .at

these converging surfaces. Thus, the tooth {will be rigidly held by the base, vertical shifting being prevented by the V engagement seen in a longitudinal vertical plane, and lateral shifting being prevented-bythe V engagement seen in a section perpendicular to the longitudinal axis of the tooth.

.- When the teeth of'Figs' l to 8 are originally sold, they may be-a single casting or forging, and

require a departure from smoothness.

the body portion I2 will be extended to the point. The contour of the original tooth may be approximately as shown for the composite tooth in Figs. 1 and 2 or it may be quite difierent. Of course, the top'and bottom converging faces of a new tooth would usually be smooth except insofar as special features of shape might After the point has been worn down on one side, the tooth may be turned over to wear the point down on the other side, although this is not usually necessary with the present invention.

When the tooth becomes worn to a point where it becomes unsatisfactory, a new point 2|, called a repointer, is welded thereto. Usually it will be necessary to trim the bodyportion l2 with a torch (burn it) to the proper shape to permit the welding. The new tooth is preferably provided with a guiding ridge 20 to serve as a pattern. The preferred shape that the body portion I 2 should have prior to welding is clearly shown in Fig. 2'. The tooth is burned straight across between pattern ridges 20.

It will be observed that the point 2| does not fit snugly around the end of the body portion [2. In fact, each of them is of generally convex configuration. The purpose of this is to give access for welding. Usually the portion 22 will be filled in by welding first, thus providing an integral structure from the center line of the tooth to the top face of the tooth. This entire gap will be filled in solidly as shown. Next, the portion 23 shown in Fig. 3 will be welded in all the way across the tooth. The provision of the groove 24 inthe underface of the tooth indicates to the welder the depth to which this weld 23 should be extended all the way across the tooth. Thereafter the portions 26 will :be'filled in by welding, thus providing a continuation of each rib 21 at the two sides of the groove 24. This method of welding provides a construction which has been found to have adequate strength for heavy duty excavating implements.

An even more important function of the groove 24 is in causing the tooth to wear sharp. It will be obvious that as the ribs 21 wear o1f,'the tooth will be considerably thinner than if-the channel 24 had been solid metal and the wear distributed all along this solid metal. From one standpoint, it might be said that the provision of channel 24 causes abalanoe in the wear of the'tooth so that it wears thinner at the rightspeed to keep step with its wearing shorter. The tooth cannot be made thinner initially for it-would not have adequate strength. The ribs 21 give 'adequate strength to the point although they wear down fast enough so that the tooth may be said 'to be self-sharpening. In short, the provision of the groove 24 extending to the tip of thetooth and of increasing width and depth rearwardly causes the vertical or upward diminution of the tooth to keep pace quite well with the rearward diminution, so that for aconsiderab'le period: of wear the thickness of the front end of the tooth is not excessive or, in other words,'-the toot stays reasonably sharp.

Having the tooth reduced in thicknessto keep step with its shortening may not be quite the whole story since teeth in the past have had a tendency to wear rounded to the shape of a sled runner. The present tooth largely avoids this and it is believed that there are two factors which contribute toward it, one .being the provision of the channel 24 and the ribs 21" and the other being the initial shaman-mg of the toothwitha the tooth is being slid forwardly in the digging operation. It should be borne in mind that one common use of drag-line buckets for example is to strip coal or other material from a rock strata.

As seen in Fig. 1, the front end portion 29 of j the ribs 2'! is considerably wider than the rearward portion of the ribs 21. This has been found to increase both the strength and the wearing qualities of the forward portion of the point without disadvantage, since the tooth remains sharp as this portion of the tooth wears. It is desirable to shape the ribs so that they will wear just'fast enough at each stage of wear to keep the tooth sharp.

Of course the exact shape which would be ideal from the standpoint .of wear might vary somewhat with the nature of the digging operation. All of the shapes shown have been found to be fairly satisfactory. Those shown in Figs. 10, .11, 14 and 15 are now preferred, it being noted that the width of the groove 24 at the up is approximately thirty percent of the width of the tooth at .the tip. Further back, where the ribs Z'lhave greater depth to wear down, the groove is relatively wider and hence the ribs relatively narrower.

The groove 24 is valuable from the standpoint of efficient use of metal as Well as from the standpoint of longer life. Even if the point became dull slightly faster with the groove 24 than without, there would still be the advantage of using fewer'pounds of point for a given number .of hours of operation .than if the groove 24 were not provided.

The groove 24 has been shown as continued into the body portion of the tooth as at 3|. is not necessary but avoids having a projection which might strike rocks as the tooth is moved forwardly. When new teeth are provided with a groove 24in casting, the groove will naturally be extended back fora gradual termination, as shown. However, when the tooth is not originallyso formed, it will be optional whether or not the continuation groove 3| is burned into the body portion.

The shape of the tooth shown in Figs. .1 to 3 is at present the preferred shape. The radius of longitudinal curvature of the faces 32 is about eight to ten inches, although it is'not at all objectionable for .the upper face to be flat. The face 33 inside the groove has been illustrated as being fiat at the front portion and then curved from there rearwardly. The various teeth are drawn approximately to scale. Of course, the size and shape of point will depend somewhat on the shape and size of the tooth for whichit is designed, and in any event variations may be This takes place. ures, the repointer may be weldedto thebase first 2,369,285 21 have a flattaper 38 instead of a curved con Each of these features, the forwardly widened point and the flatly tapered rib, isoptour.

tional with the different shapes of vertical cross section shown. l i

The repointer could of course be a little thicker at its rear end than has been shown sothat it would correspond in thickness more to an extension of the body 12, indicated by the dotted lines 4|. However, it is preferred tohave the repointer slightly slimmer than the distance between the lines 4! so that the projecting ridge 42 will form a transverse guide for burning oif the tooth to receive a new repointer. A new tooth is preferably of the same shape as the repointed toothhere shown soas to provide guide ridge [42 as well asthe demarcation or ridge 2t. Even if ridge d2 should be worn 01f slightly before a repointer was applied, the wear would produce a visibleguide line.

In the form of tooth shown in Figs, 8 to 11, means is provided for correctly positioning the all of the teeth will be properly aligned. The proper alignment of the various teeth on a dipper is desirable partly to insure the self-sharpening wear of the teeth so that the dig line will be i straight and horizontal. The latter reason is tooth repointer on its base during welding so that especially important where a rock strata is being stripped of coal since it is desirable to clean the "coal from the rock as thoroughlyas possible.

As is perhaps most clearly seen in Fig. 8, the

tooth base 5! is provided on each side with a small recess 52, the top and bottom faces of which converge slightly rearwardly to form a V-shaped notch. The repointer 53 is provided with correspondingly shaped tongues 54. Because of their V-type of engagement with the recesses 52, the tongues 54 accurately align the repointer 53 with thebasefil.

This not only positions the repointer accurately but also holds it while the welding process As in the case of the previous figalong the bottom as at 5% and then along the top as at 58, or vice versa.

Usually the base 5: will be suppliedwith the recess 52 cast therein and the repointers 53 will,

of course, always be formed by casting or otherwise with the tongues 5 3 there-on when they are to be used with the base 5!. Of course if bases 5! having the recess 52 therein are not available, such recesses can be cut in old worn teeth with a cutting torch.

In Figs. 12 to 15, another form of repointer has been shown which has an advantage of simplified welding. The welding is simplified be-. cause although it extends over longer lines, there is no plane of cleavage and the welded bead may be much thinner.

In this instance, therepointer BI is provided with rearwardly diverging legs Gland 63. The leg 63 is provided with an, opening 64 therethrough which serves the dual purpose of continuing the groove 24 and permitting access, to.

align the repointer and help hold it in position for welding. l l l l The legs 62 and 63 do a large shareof holding the repointer. on the base and since there is no plane of cleavage, a minimum of welding will be sufficient. To a lesser'extent, this same advantage is'obtained in the structures of Figs. 8 to 11 since the tongues 54 interrupt the plane of cleavage which would be present without said tongues and to the extent of theirstrength reduce the amount of welding necessary.

From the foregoing it is seen that a tooth point-shape is provided which makes the tooth self-shapeningin wear, and makes it sufiiciently" strong to withstand heavy duty. Furthermore tooth repointers (preferably of this shape) and methods of welding the same to the tooth base have been provided which effect a tremendous saving in metal as compared to replacement of the teeth, which may be welded so easily that the cost of welding is much less than heretofore, and

which in the preferred forms are self-aligning prior to welding. V i Fig. 16. shows another invention ofapplicants which may be described here very briefly since it is a divisible invention and will be the subject of another application. Thisrefers to the shape of the drag-linebucket 6|. An important feature is that the foremost parts of the bucket are heavy hitch plates 62. The tips 63 of these hitch plates extend beyond the mounting facili-.

ties for hitch links 64 so as to serve as bumpers when the bucket is dropped to th ground in dumped position (front end first). The hitch links 64 automatically fold in so that the chain connected to them will not be injured. The arch 66 rises vertically from apoint forward of the teeth but rearward of the bumpers 63 so that it rarely strikes the ground. Furthermore, its center portion 61 is shaped to be approximately aligned with the direction "of movement of the bucket in being dropped so that if it does strike it will strike fully edgewise and hence not be caved in. The balance of the bucket is exceptional. 1 l l i We claim: 1. A tooth repointer for excavating implements and thelike, having upper and lower faces con verging forwardly toward the tip and having a longitudinally extending groove of such dimensions that innormal use of the point the upward diminution of the point will keep pace with the rearward diminution sumciently closely to maintain reasonable sharpness of the tooth asit wears rearwardly a substantial distance from the original tip, the downwardly exposed face within the groove being approximately parallel to the upper faceof the point for approximately at least one inch rearwardly from the tip of the point, and the groove widening rearwardly from the tip as it deepens, said repointer-being convexly shaped on its rear end to facilitate welding it "to a base tooth portion, and said groove being open at the rear end, thus demarking anarea which neednot be welded.

2. A tooth repointer for excavating implements and the like, having upper and lowerfaces converging forwardly toward the tip and having a longitudinally extending groove of such dime'nsions thatin normal use of the point the upward diminution of the point will keep pace with the rearward diminution suificiently closely to maintain reasonable sharpness of the tooth as it wears the tooth base 66 isproperlyshaped it willbe observed that the legs Bland 63 will properly rearwardly a substantial distance from'the original tip, said repointer being convexly shaped on.

its rear end to facilitate Welding it'to a base tooth portion, and said groove being open at the rear end, thusdemarking an area which need not be welded. i

3. A tooth for excavating implements and the like including opposedfaces converging forward- 1y toward a tip to form a point, and having contour changes forming demarcations rearwardly of the pointadapted to serve as guides for burning, off the point along a path which will leave a convex surface on the'front end of the remainder of the tooth appropriate for welding theretoa repointer having a convex rear face.

4. A tooth repointer for excavating implements and the like, having upper and lower faces converging forwardly toward the tip and havinga longitudinally extending groove of such ;dimen- ,sions that in normal use of the point the upward diminution of the point will keep pace with the I rearward diminution sufficiently closely to maintain reasonable sharpness of the toothas it wears rearwardly a substantial distance from the original tip, and the tip of the tooth sloping downwardly and forwardly substantially to the bottom of the tooth whereby the tooth is self-shapening as it wears, said repointer being convexly shaped on its rear end to facilitate welding mm a base tooth portion, and said groove being open at the rear end, thus demarking an area which need not be welded. and a tongue formed on the rear of the repointer with rearwardly converging faces to fit in a correspondingly shaped pocket of a member to which it is to be welded to properly align the repointer thereon.

5. A tooth repointer for excavating implements and the like, having upper and lower faces converging forwardly toward the tip and having a longitudinally extendinggroove of such dimensions'that in normal use of the point the upward diminution of the point will keep pace with the rearward diminution sufiiciently closely to maintain reasonable sharpness of the tooth as it wears rearwardly a substantial distance from the origbeing convexly shaped on its rear end to facilitate of a suitable metal for tooth points, shaped to form a tooth point, with opposed faces two of which converge toward the front end, and having rear face portions converging from opposed faces approximately to an intermediate point to permit access for welding between the said rear aeeaess faces andthe generally convex end of the body portion of a tooth, and a tongue formed on the rear of the repointer with rearwardly converging faces to fit in a correspondingly shaped pocketof a member to which it is to be welded toproperly align the repointer thereon.

7. A tooth repointer for excavating implements and the like, havin upper and lower faces converging forwardly toward the tip and having at least one longitudinally extending groove in the lower face extending, at one longitudinal position, over half the width of the tooth and approx imately half the thickness of the tooth, and including legs diverging rearwardly to fitover a correspondingly shaped tooth base portion for welding thereto, said groove forming an opening through one leg to give access to welding near the tip of the nose. l

8. A tooth repointer for excavating implements and the like, having upper and lower faces converging forwardly toward the tip and having a longitudinally extending groove, said repointer welding it to a base tooth portion, and said groove being open at the rearend, thus demarking an area which need not be welded.

'9. Atooth for excavating implements and the like, including a base and arepointer welded thereto and having upper and lower faces con-- verging forwardly toward the tip and having a longitudinally extending groove, said repointer and base being convexly shaped on their adjacent ends to facilitate welding them together, and said groove being open at the rear end of the repointer, thus demarking an area which need not be welded.

10. A tooth for excavating implements and the like including a base having a generally convex end, and a repointer comprising a block of a suitable metal for tooth points, shaped to form a tooth point, with opposed faces two of which converge toward the front end, and having rear face portions converging rearwardly from op- .posed faces approximately to. an intermediate point to permit access for welding between the said rear faces and the generally convex end of the base, and a tongue formed on the rear of the repointer with rearwardly converging faces and fitting in a correspondingly shaped pocket in the base, said tooth being welded to the base in the f alignment determined by said tongue and pocket.

11. A tooth base for excavating implements and the like having a convex end adapted to have a repointer Welded thereto and having asmall pocket in a forward portion of the end with rearwardly converging faces to fit a V-shaped tongue on the rear of the repointer which is to be welded to the base to properly align the repointer on the .base.

ARTHUR W. DANIELS. JOSEPH P. MURTAUGH.

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